Resin molded body, production method and apparatus of the same, and means for giving improvement of fluidity of molten resin

Abstract

To provide a means for producing a foamed molded body free from or small in reduction of physical characteristics, and having a clean and smooth surface in foam molding of a resin including an ester structure.SOLUTION: A production method of a resin molded article includes: a process of increasing fluidity of a molten resin by putting a liquid to a molding resin in a heating cylinder when melting and kneading a molding material so that the liquid vaporizes to become vapor by a temperature of a heating cylinder and molten resin, and dissolving under pressure or / and finely dispersing the vapor of the liquid by physical strength such as screw rotation in a process of charging a molding material comprising a thermoplastic resin as a main constituent in a molding machine heating cylinder, and melting and kneading (including plasticizing, and measuring) the molding material; and a process of filling the molten resin increased in fluidity inside a cavity.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present invention relates to a resin injection foam molding process in which foam molding is performed using a gaseous or / and (in the present invention, "or / and" can also be read as "at least one or more"), liquid or / and, solid foaming agent at 23°C and 1 atmosphere of pressure, i.e., NPT, The mold structure is either two-plate or three-plate or more, and the cavity is filled with foamable resin, followed by molding back and / or core back to provide a means for obtaining a foamed molded product with a high expansion ratio. "Gaseous, gaseous" refers to the gaseous state, "liquid, liquid" refers to the liquid state, and "solid state" refers to the solid state, and all refer to the state in NPT. [Background technology]

[0002] Patent Document 1 describes a foam molding method in which a molding material consisting of a resin (plastic) and a foaming agent is shot into a mold in which an insert is placed, leaving an unfilled portion, and the unfilled portion is filled by the expansion force caused by the foaming of the foaming agent. The resin consists of a base resin and a low molecular weight resin of the same type as the base resin but with a lower molecular weight than the base resin. Patent document 2 explains the Gas Counter Pressure (GCP) method, a method for suppressing swirl marks (foam stripes, abbreviated as "SM") that occur on the surface during foam molding, and its mold structure, and describes the use of a U-shaped O-ring and a weighted O-ring. Patent Document 4 describes and fully explains foam molding using a liquid, but does not specifically show, in examples, that water is the only foaming agent useful for foam molding of polymer alloys of PC and PC-based resins, or that the use of a foam nucleating agent to make foam cells finer. Patent Documents 4, 5, 6, and 7 describe a means for sealing an ejector pin with a load type O-ring, but do not describe a specific means for fixing an inclined pin for a slide core using a nest or the like, and further fixing the nest with a bolt to seal the rod of the inclined core with a load type O-ring. Patent Documents 4, 5, 6, and 7 explain the means of increasing the expansion ratio using a mold back and a core back, but in a mold with a structure of three or more plates, the expansion ratio cannot be increased unless the PL is opened first. There is no description of a structure in which the PL must be forced to open first by using a spring or the like. In addition, there is no description of a mold structure in which the stripper plate is opened first, the pin gate is cut, the PL is opened, and mold back and core back are performed (executed), in which a spring or the like is inserted in both the stripper plate and the PL to allow the PL to move back a certain amount (distance). Patent Documents 4, 5, 6, and 7 show a die structure using two sets of ejector plates, a plate on which ejector pins, which are extrusion shafts, are arranged, and an ejector plate on which an outer cylinder that retreats before fluid pressurization is arranged, as a die device for pressure molding. In pressure molding, if gas gets into the molded product, it is no good, and it is shown that the outer cylinder is retreated before fluid pressurization to create a space so that the pressurized fluid can enter the gap between the mold and the resin, and the pressure of the pressurized fluid is dispersed and it does not become hollow, but it is not shown that in so-called hollow molding, in which the pressurized fluid is poured into the molded product to create a hollow section and pressurized from within the hollow section, the pressurized fluid inside the hollow section is no longer necessary after sufficient pressurization, and the means of eliminating the residual pressure by retreating the gas injection pin (the fluid pressurization pin that forms a hollow section inside, the pin used for fluid pressurization) and exhausting the residual pressure all at once in order to completely eliminate the residual pressure, which is a problem in blow molding, can be easily and reliably solved. Mitsubishi Gas Chemical Company, Inc. has shown a gas injection nozzle structure (Simpless Nozzle) equipped with a hydraulic cylinder for blow molding, but the hydraulic cylinder gets in the way and gas cannot be injected at the desired location.Also, when gas injection from multiple locations is required, the installation of the ejector pins on the mold is greatly restricted by the gas injection nozzle equipped with the hydraulic cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-103919 [Patent Document 2] Japanese Patent Application Publication No. 11-216748 [Patent Document 3] International Publication No. 2003 / 026357 [Patent Document 4] International Application No. PCT / JP2015 / 062611 [Patent Document 5] International Application No. PCT / JP2015 / 069216 [Patent Document 6] International Application No. PCT / JP2016 / 086380 [Patent Document 7] International Application No. PCT / JP2020 / 15536 DISCLOSURE OF THEINVENTION

[0004] (Problem to be solved by the invention) The objective of the present invention is to obtain a foam-molded product with a high expansion ratio by filling the cavity with a foamable resin, followed by mold-backing and core-backing to open the cavity. (Means for solving the problem)

[0005] The mold is equipped with a mechanism (pre-mold opening mechanism, mold opening mechanism, mold opening mechanism) that forcibly opens the PL of the mold when mold back or core back is performed.

[0006] (composition) The first invention described above involves the process of putting resin into the heating barrel of a molding machine and melting the resin (heating it to melt it), then adding (injecting into the heating barrel) a volume-controlled amount of a substance that shows liquid at a temperature of 23°C and a pressure of 1 atmosphere (atm, 76 mmHg, 1013 hectopascals) to the molten resin (resin in the melting zone of the screw) that has been compressed to increase the density of the molten resin (resin in the compression zone of the screw), and vaporizing it depending on the heating temperature and the temperature of the resin. The vapor (gas) is pressurized and dissolved in the molten resin by the force of the screw rotation and / or finely dispersed, which reduces the viscosity of the molten resin and improves its fluidity. Molten resin with improved fluidity has lower flow resistance when filling the cavity, making molding easier (filling can be done at low pressure). The viscosity of the molten resin is reduced by the gas produced by vaporizing the liquid, and the molten resin with improved fluidity is filled into the cavity by providing a cushioning amount to the screw (providing a cushioning amount so that resin dwell pressure can be applied after filling). After filling, resin dwell pressure is applied using the screw to crush the foam layer and foam cells, and increase the density of the molten resin. Although liquid is used, as shown in Patent Document 4 and other documents, liquid acts as a foaming agent, so using resin dwell pressure is effective in obtaining molded products that do not foam, do not have a foam layer, and do not have foam cells. In addition, high-pressure GCP, blow molding, and pressure molding can also crush the foam layer and foam cells, and foaming gas, liquid, etc. are pushed out of the molded product. The molded product obtained in this way has almost no difference in weight from the molded product molded without using liquid. Since the fluidity is increased, the transmission of resin dwell pressure is sufficient. In some cases, the product may be heavier than when no liquid is used. Such weight changes depending on the resin holding pressure.

[0007] In some cases, liquid and, if necessary, gas may be used in combination to increase fluidity. Conventional molding conditions for injection foam molding (filling into the cavity) are such that, in the case of hydraulic machines, no holding pressure is used, so the screw is generally pushed all the way to its forward end. If necessary, to avoid the reaction during filling {the screw is returned by the pressure (reaction force) of the molten resin filled in the cavity}, a weak holding pressure is applied for a short period of time, around 0.5 seconds, after the screw has been pushed all the way, and the screw is stopped in place to stabilize the amount of molten resin filled into the cavity and stabilize the foaming. The electric motor pushes the screw all the way to the VP switching position, and then, if necessary, the screw is stopped once to stabilize the filling amount. In this invention, neither the hydraulic machine nor the electric motor pushes the screw all the way, but instead, as in conventional general molding, a sufficient cushion amount, for example, about 20% of the product weight, is provided, and the molten resin containing the liquid and gas is filled into the cavity, and the resin is then held at sufficient pressure and for a sufficient period of time. For example, the liquid is used to eliminate sink marks, which are defects in appearance, which is a major difference (distinction) from conventional injection foam molding. In other words, the present invention is a general molding process using a resin with a significantly improved fluidity and a reduced viscosity of the molten resin by using a liquid or the like. Although the above liquids are used to increase the fluidity of molten resin, the fluidity can also be increased by simply applying fine embossing or ceramic coating such as TiN, CrN, WC, or DLC to the surface of the mold, i.e., the surface that comes into contact with the molten resin (not only the fixed side of the design surface, but also the movable side of the non-design surface), so if this is done at the same time as using the above liquids and gases, the fluidity will be further improved by a synergistic effect. It is preferable to use a shut-off nozzle to prevent snot. It has been explained that the liquid is put into the heating barrel, but it is also possible to provide an inlet for injecting the liquid into the nozzle, inject the liquid at the injection stage of the molten resin, and pressurize it to melt it and finely disperse it to increase the fluidity of the molten resin.

[0008] (Difference between foam molding and general molding.) When thermoplastic resin is heated and melted in a heating cylinder, it becomes molten and has fluidity. This is now called the "molten state", or "a state that has fluidity or has been made to have fluidity", "a state that can flow", or "a state that has been heated and melted and has fluidity or has been made to have fluidity". In the heating cylinder, the molten resin is subject to back pressure and other pressures, so the density of the molten resin is somewhat high. When the molten resin in the heating cylinder starts to be injected (filled) into the cavity, the molten resin filled in the cavity is released from the pressures, such as the back pressure and filling pressure, that are applied to the molten resin during the filling process. If the molten resin is filled to the fullest in this state (assuming that the volume of the cavity and the volume of the molten resin are the same) and then cooled and solidified in the cavity, the volume of the molten resin will decrease by about 5% for styrene-based resins such as ABS and about 10% for olefin-based resins such as PP when it is cooled and solidified. This is called molding shrinkage, and as a result of molding shrinkage, a defect in appearance called "sink" occurs in the molded product. To eliminate this sink and obtain a molded product with a clean surface and smooth, inconspicuous sink marks, a process called resin holding is generally carried out, in which the screw of the molding machine is used to fill the cavity with more molten resin than was filled (the amount equivalent to the volumetric shrinkage, for example, 5% or more for ABS), increasing the density of the resin and eliminating the sink marks (this is the "resin holding" process). Naturally, the higher the pressure of the holding pressure, the higher the density of the resin and the fewer sink marks, but burrs will form on the PL, etc. When resin holding pressure is applied, the density of the resin near the gate is high and the density of the resin at the end of the flow is low. If the pressure of the resin holding pressure is increased, this difference becomes large, and as a result, the internal stress of the molded product increases, and the warping and deformation of the molded product becomes large. The inventor previously observed mass production of automobile parts using a high resin holding pressure of 100 MPa. Unless the pressure is increased to this level, it is not possible to eliminate sink marks caused by ribs or other components in some molded products.

[0009] If so, in order to minimize the pressure retention effect between the gate vicinity and the end of the flow, if the melting temperature of the resin is increased, the fluidity will increase (improve), and the pressure retention effect will reach the end of the flow, but if the temperature of the molten resin is increased, the density of the resin in the molten state will become lower, so the sink marks will be larger compared to the molded product before the temperature of the molten resin was increased. Also, the time required for cooling and solidification will be longer, which will reduce productivity.

[0010] In that case, as a means of increasing the fluidity of the resin without raising the resin temperature, the resin can be improved or modified using flow aids, flow improvers, low molecular weight resins, etc., as described below. However, in this case, an increase in the unit price of the resin cannot be avoided by using additives to the resin, and improving or modifying the resin with additives, etc., reduces the physical and chemical properties of the resin, resulting in a decrease in the strength of the molded product.

[0011] (Method of improving the fluidity of resin by using liquid.) The inventors have previously applied for a foam molding method using a liquid (International Application No. PCT / JP2015 / 062611, including Patent Document 4), but instead of using a liquid as a foaming agent as shown in Patent Document 4, if a volatile, vaporizable, low-boiling liquid is added to the resin in the melting stage in the heating cylinder, the molten resin, the liquid acts as a fluidity improver. They have found that the fluidity of the molten resin can be greatly improved without raising the temperature of the molten resin or using additives. Moreover, they have found that the liquid can be squeezed out of the molded product by using a dwell pressure, which is about the same as the dwell pressure used during general molding, without using a high dwell pressure. By using a liquid, they have solved the above-mentioned problems when the melting temperature is increased, the economic problems when additives are used, and problems such as deterioration of physical properties.

[0012] Patent Document 4 and other documents also describe resin dwell pressure in injection molding in which foaming is imparted using a liquid. This has the risk of the screw being returned by the pressure of the foamable resin filled in the cavity. When the screw is returned by the reaction of the foamable resin filled in the cavity {the force of the foamable resin filled in the cavity (the foaming force of the filled foamable resin, the reaction force of the foamable resin trying to return inside the screw, etc.)}, the variation in weight of the foamed molded product increases, resulting in short molds, overpacking, etc. In the case of foam molding, if a dwell pressure of about 30% of the resin dwell pressure used conventionally is applied for about 0.5 seconds after the cavity is filled to the brim with the foamable resin (the stage of completion of filling pressure and temporary pressure), the screw will not be returned, and a foamed molded product with a stable weight can be obtained. If a dwell pressure of several seconds, or in some cases several tens of seconds, is applied at a high pressure similar to that of general molding as in the present invention, the foamed core formed by the liquid will be crushed. Since the purpose is to crush the resin, high pressure (pressure that increases the density of the resin) is applied for a long time {so that the action and effect of the resin holding pressure is fully transmitted (acts) on the molten resin in the cavity.} In other words, there is a difference in the purpose and process of the holding pressure, and this is where Patent Document 4 and other documents differ from the present invention. This invention uses a liquid foaming agent, but is characterized by not foaming the resin. Patent Document 4 and other documents say that the screw is stopped at the forward end, but in this invention, resin holding pressure is applied after filling, so a cushion amount is left during filling.

[0013] Patent Document 4 and others describe the Gas Counter Pressure method (GCP method, or simply "GCP"). This describes the means, steps of eliminating swirl marks in foam molding and obtaining a foam molded product with a clean and smooth surface. In the present invention, the fluidity of the molten resin is improved, and the swirl marks caused by the liquid (or silver streaks caused by the use of the liquid) are eliminated, and this is similar to the case of undried ABS, which will be described later. In order to eliminate swirl marks caused by the liquid (silver streaks caused by the use of the liquid) and obtain a general molded product with a clean and smooth surface without liquid or silver streaks on the surface due to other reasons, it is necessary to use GCP. In this case, the pressure of the GCP may be higher than 1 MPa in the examples of Patent Documents 4 and 5, since it does not matter if the internal foam cells are crushed by the pressure of the GCP. When compressed air molding is used in combination, the foam cells are crushed by the high-pressure gas injected into the gap between the resin and the mold, and the product becomes solid (does not have a foam layer). Therefore, the steps, objectives, and actions and effects of the GCP of the present invention are different from those of the present invention. However, the purpose of applying embossing to prevent raindrops (i.e. trapping the gas in the GCP) remains the same.

[0014] If the fluidity is increased by the liquid, the packing pressure is reduced and the internal stress of the molded product is reduced. As a result, a general molded product is obtained with little warping or deformation but without an internal foam layer. If the fluidity is increased by the liquid, the resin packing pressure (through the spool, runner, and gate) is reduced, so the difference in the packing effect between the vicinity of the gate and the end of the flow (the difference in the packing pressure transmitted) is reduced. As a result, there is less flash on the PL near the gate and on other PL. By using liquid to increase the fluidity of resin, the resistance to filling the cavity is reduced. The resin holding pressure is also reduced, which results in a reduction in the clamping force. This allows large molded products to be processed using a molding machine with a smaller clamping force, resulting in energy savings.

[0015] As mentioned above, once the liquid in the molten resin has completed its role of improving fluidity (when the molten resin has finished filling the cavity), the liquid is squeezed out by the resin holding pressure and does not remain in the molded product. The strength of a general molded product obtained in this way is no different from that of a general molded product made using general resin that has not been modified to improve fluidity. On the contrary, the density of the resin is increased even more, so a molded product with high strength can also be obtained. This is also a difference from foam molding in Patent Document 4 and the like. The foam cells inside the foam molding are actually sink marks generated inside. In other words, foam molding is a molding method that moves sink marks to the inside. In foam molding products such as ABS and HIPS, if there are swirl marks on the surface, the impact strength decreases by about 60% to 70%. Even if a skin layer is formed on the surface using GCP (Gas Counter Pressure), the impact strength decreases by about 30%. Even in foam molding in which foam residue does not remain in the molded product using liquid, since it is foam molding, the physical properties are significantly reduced even with only the weight reduction (weight reduction of 5 wt.%) by not using holding pressure. The strength of a general molded product using resin holding pressure and a general molded product that does not have foam cells inside, which is not foam molding using resin holding pressure, by increasing the fluidity using liquid, is approximately the same. This is the invention of improving fluidity using liquid of the present invention, and the inventor asserts that these differences from Patent Document 4 and the like are the novelty and inventive step of the present invention. The liquid injected into the heating cylinder to increase the fluidity of the molten resin in the heating cylinder may be one type, or a mixture of several types of liquids.

[0016] Not only liquids but also gases may be used in combination (when gases are used in combination in the present invention, it is expressed as "liquids and gases in combination as necessary", "liquids and gases in combination as necessary", or simply "liquids and gases", since the present invention asserts that gases can be used in combination with liquids). Here, the "stage" of melt kneading refers to the stage at which the molding material starts to melt due to the heat of a heater or the like provided in the heating barrel, for example, the stage at which about half is melted, the stage at which it is almost melted, or the stage at which it is completely melted. The "process of filling the cavity" refers to the process of filling the cavity (molding space) with the molten resin, and refers to any of the stages at which filling begins, or the stage at which about 80% of the cavity volume is filled, or the stage at which filling is almost completed, or the stage at which filling is completed (for example, the completion of the primary pressure in an injection molding machine).

[0017] The "process of increasing the density of the resin" generally refers to filling the cavity with molten resin and then applying a resin dwell pressure using a screw, as well as blow molding, a means of pressurizing the molten resin from the inside using a gas at atmospheric pressure or higher, compressed air molding, in which the gas is introduced into the gap between the resin and the mold and pressure is applied from the outside of the resin, and compression molding using the mold clamping mechanism of the molding machine. In some cases, these methods may be used in combination.

[0018] In order to stabilize the resin holding pressure, the inventor has determined that there are two types of molding machines: one with a specification (program) that allows the time (t1) for filling the cavity with molten resin to be set independently of the time (t2) for resin holding pressure (secondary pressure, tertiary pressure, etc.), and another with a specification that controls t=t1+t2, the total time of t1 and t2. To stabilize the action and effect of holding pressure every time (shot), it is preferable to be able to set t1 and t2 separately. Of course, it is also possible to control the total time t=t1+t2.

[0019] (Action and effect) Because the fluidity of the resin is increased, there is less resistance to filling the cavity. The pressure holding effect is also increased, making it possible to fill the cavity and hold the resin at a lower pressure than in regular molding. This is superior to the pressure holding effect in regular molding that does not use liquids or gases, and even at low pressure holding there are fewer sink marks and less flash such as PL. Furthermore, because the pressure setting for resin holding is low, the resulting molded product has less warping and deformation than regular molded products. Since the filling resistance is reduced, the resin holding pressure can be reduced, and the clamping force can be reduced, which results in the processing of molded products with large projected areas using injection molding machines with small clamping force (small size). This has the effect of reducing processing costs and saving energy. For molding resins with low fluidity such as super engineering plastics and molding materials containing inorganic fillers, the range of molding condition settings is expanded, and molding processing becomes easier by using molten resins with improved fluidity by using gas as necessary to turn them into liquids.

[0020] (composition) The second invention described in claim 2 shows a process of filling a cavity with molten resin whose fluidity has been increased by using a liquid or the like, and then applying a resin dwell pressure to increase the density of the resin.

[0021] (Action and effect) In the second invention described in claim 2, a cavity is filled with molten resin whose viscosity has been reduced and whose fluidity has been increased by using a liquid or the like, and since the fluidity of the molten resin is increased by the liquid or the like without increasing the melting temperature, when a resin holding pressure is applied after filling, the effect of transmitting the resin holding pressure is enhanced, and the action and effect of the resin holding pressure are higher than when the fluidity is not increased. If more resin holding pressure than necessary is used in an attempt to eliminate sink marks, the molded product will have significant warpage. Using high holding pressure will increase the occurrence of burrs in the PL and shorten the life of the mold. Using high resin holding pressure naturally requires high mold clamping force, which requires a larger molding machine, which is not economical. Molded products processed using resin with increased fluidity solve the above problems.

[0022] (composition) The third invention described above uses the liquid of the first invention described above, and also gas if necessary, to fill the cavity with molten resin whose fluidity has been increased by injecting a high-pressure gas into the molded product to create a hollow space inside the molded product using the gas, and pressurizes the internal hollow space. In addition, the molten resin may be pressurized from the inside by simultaneously applying pressure to the resin from the outside. Compressed air molding may also be used if necessary.

[0023] (Action and effect) The third invention described above shows the manufacture of hollow molded products. In the case of hollow molding, when the viscosity of the molten resin decreases (fluidity improves; in the case of molten resin with high fluidity), the pressure of the injected gas is reduced, and as a result, the internal stress decreases, resulting in a hollow molded product with high dimensional accuracy and little warping or deformation.

[0024] (composition) The fourth invention described above uses the liquid of the first invention described above, and also gas if necessary, to fill the cavity with molten resin whose fluidity has been increased, and introduces a high-pressure gas into the gap between the mold and the molten resin, pressurizing the molten resin from outside with the gas to increase the density of the resin. At this time, resin pressure holding and blow molding are also used if necessary.

[0025] (Action and effect) The fourth invention described above shows the manufacture of pressure-molded products. In the case of pressure-molding, when the viscosity of the molten resin decreases, gas at high pressure easily enters the gap between the resin and the mold. Also, the action and effect of the gas (compressed air) with high pressure compressing from one side of the molten resin in the cavity (generally the movable side of the non-garment surface) to the other decorative surface (generally the fixed side) becomes stronger, so the transferability to the mold increases. When a highly fluid molten resin is used, the gas pressure of the pressure-molding can be reduced, resulting in a pressure-molded product with less warping and deformation. Furthermore, the transferability can be further improved by using resin pressure retention in combination. If necessary, hollow molding may also be used.

[0026] (composition) The fifth invention described in claim 5 is based on the inventions described in claims 1 to 4, and uses a sealed mold to pressurize the inside of the mold at atmospheric pressure or higher (by applying a GCP process), and fills the mold with molten resin whose fluidity has been increased by using a liquid, and if necessary, a gas in combination.

[0027] (Action and effect) The fifth invention is based on the inventions described in claims 1 to 4, and uses a GCP process in which the inside of a sealed mold is pressurized (pressurized) to atmospheric pressure or higher beforehand, and then fills the mold with molten resin with increased fluidity using a liquid and, if necessary, gas, in the mold, resulting in molded products, blow molded products, and compressed air molded products with clean, smooth surfaces free of swirl marks (foam stripes) caused by vaporized liquid and gas. When the fluidity of the molten resin is high, even a low-pressure GCP (pressurization, pressurization inside the mold) makes it possible to process molded products with fewer or no swirl marks.

[0028] (composition) In the ninth invention described in claim 9, liquid is first injected from an injection port on the side closest to the hopper provided on the heating cylinder of the molding machine, the viscosity of the molten resin is reduced by the vapor of the liquid, and then gas is injected from another injection port into the molten resin containing the vapor of the liquid. This order is not limited to injection molding and can also be implemented in extrusion molding machines. In order to prevent the liquid vapor and gas from escaping to the hopper side through the screw, a backflow prevention ring (check valve) is provided at the rear {behind the injection port for injecting the liquid, escaping (leaking) to the hopper side}, and this structure is not limited to the screw of an injection molding machine, but can also be implemented in the screw of an extrusion molding machine.

[0029] (Action and effect) In the ninth invention described in claim 9, liquid is first injected into the molten resin in the heating cylinder, and the vapor of the evaporated liquid lowers the melt viscosity of the molten resin. Gas is then injected into the molten resin with this reduced viscosity. Compared to when liquid is injected first, the viscosity of the molten resin is lowered, so the gas easily enters, and because the viscosity is low, the gas easily dissolves or finely disperses in the molten resin due to the back pressure and the force of the screw rotation.

[0030] In claim 9, a backflow prevention ring is provided at the rear to prevent the foaming gas from escaping (leaking) from the hopper at the rear. The backflow prevention ring is used to send the metered and plasticized molten resin to the front of the screw to prepare for injection. In the case of foam molding, foaming is imparted (added) using a foaming agent that is liquid, gas, or solid, so that the foaming force does not cause the resin to return to the screw side again (there is no need to worry about the resin returning due to the foaming force during metering because back pressure is applied, but after metering is completed and before the start of filling, when the resin is stored in front of the heating barrel, there is a risk of the resin returning to the screw due to the foaming force). In addition to the backflow prevention ring at the rear of the screw, a backflow prevention ring is also provided at the rear of the screw head to prevent the resin from backflowing to the screw side during injection. It is desirable to stop the screw once at the final stage of plasticization and metering, rotate it in reverse, and completely close the backflow prevention ring at the rear of the screw head.

[0031] (Action and effect) By providing backflow prevention rings 239, 240 at the rear of the screw, the liquid vapor that is put into the heating cylinder at the metering and plasticization stage and vaporized by the temperature of the heating cylinder and the temperature of the molten resin does not escape to the hopper, so the foaming power is stabilized. In particular, in the case of gas, it is easy for the liquid to escape to the hopper, so it is better to provide this backflow prevention ring. In the case of liquid, the liquid is introduced in the compression zone, where the resin is melted and wrapped around the screw, and the molten resin wrapped around the screw acts as the backflow prevention rings 239, 240. There is no problem with providing this backflow prevention ring. When gas and liquid are used together in this invention, the liquid is injected first, and then the gas.

[0032] Immediately after the metering is completed, there is a short delay, the screw is rotated slightly in the reverse direction, and the front backflow prevention ring 235 is closed. This prevents the molten resin, which has been given foaming properties by the liquid, gas, or solid, from flowing back toward the screw, so the weight of the molded product is stabilized. As mentioned above, this provides the effect of stabilizing the resin holding pressure.

[0033] (composition) In claim 10, if a molding resin containing resin additives such as inorganic and organic fillers, powders, and bulks (e.g., paper pulp, paper pieces, etc.) mixed therein for the purpose of improving the physical properties of the resin is simply molded, the resin additives will appear on the surface of the molded product, making it unsuitable for use in molded products and parts that require good appearance. It has been confirmed that when the resin additive is added to a resin with high fluidity, inorganic and organic matter sinks more than when a resin with low fluidity is used. By using a gas, if necessary, in combination with a liquid to improve fluidity, it is possible to prevent the resin additive from floating on the surface. Furthermore, by performing (adding) GCP, the resin additive is contained within the molded product, and a clean, smooth molded product can be obtained with no floating of the resin additive on the surface. This is the result of increasing the fluidity of the molten resin with a liquid and / or gas, and by increasing the fluidity of the molten resin, we have discovered a new action and effect: the resin additive sinks when GC is added. The resin additive acts as a foam nucleating agent, so inorganic and organic matter sinks due to the GCP. By using gas as needed in addition to the liquid, the fluidity is improved, and due to the synergistic effect with GCP, the surface of the molded product is clean and smooth, with no floating of the resin additives.

[0034] (Action and effect) As mentioned above, adding gas to the liquid, if necessary, into the molten resin increases the fluidity of the molten resin, and when a resin with high fluidity is used, the effect of GCP is increased and there is no floating of the resin additive. The inventor used PP containing 20 wt.% talc and ethanol in the range of 1.5 wt.% to 2.5 wt.% as a blowing agent, and when GCP was not performed, talc floating was still confirmed on the surface of the molded product, although it was less than in the case of general molding. In the case of GCP using air at a pressure of 1 MPa, there was no talc floating at all, and the surface was clean and smooth. The talc content was increased to 40 wt.% and 60 wt.%, but the GCP effect was sufficient and there was no talc floating in either case. In the case of polyamide containing 50 wt.% glass fiber, the result of using 1 wt.% city water as the liquid showed an improvement in the fluidity of the liquid and an improvement in the floating of the glass fiber surface with GCP.

[0035] In molded products in which the resin additive has been sufficiently sunk, the adhesion of the paint film improves, and even after 240 hours of SST (salt spray test), there is no occurrence of blisters in the paint film due to the presence of the resin additive on the surface.

[0036] In this way, it was confirmed that using liquid, and if necessary gas, in combination to increase fluidity and to improve molding processability using GCP has a significant effect.

[0037] It was confirmed that the GCP pressure can be significantly reduced when the fluidity is increased by about 2 wt.% ethanol or propanol compared to the GCP pressure required to eliminate swirl marks and obtain a smooth, clean surface for a general molded product or foam molded product when the same resin is used and the fluidity is high (resin that has not been liquidized to increase fluidity). GCP is effective in suppressing silver in general molding and swirl marks in foam molding, but it can be a nuisance when filling the cavity with molten resin as it can cause discoloration and burning of the resin, so a lower GCP pressure is better.

[0038] The inventor separately machined and installed a dulmage-shaped high-mixing part between the screw head and the screw body of a conventional injection molding machine (an extrusion molding machine is also acceptable). This makes the screw longer (L / D becomes larger), which is convenient for using more liquid, and gas in combination if necessary. However, it is obvious that this will not fit in the heater barrel as is, so the inventor machined and installed a spacer (a part that extends the heater barrel) between the nozzle head and the heater barrel, long enough to accommodate the dulmage. It is also possible to drill holes in this spacer and introduce liquid or gas through them, so there is no need to bother drilling holes in the heater barrel. In this way, by incorporating Dulmage into the tip of the screw, it is possible to eliminate problems such as discoloration and burning of the resin due to high mixing and high compression, which was a concern with screws that had Dulmage incorporated into only part of the screw in the past, by incorporating it into the front part of the screw, these problems can be eliminated.

[0039] One of the main features of this invention is to apply a dwell pressure to eliminate foam cells. In this case, the weight loss (weight loss) when using liquid, and if necessary gas, is preferably within 5wt.% of the weight of a general molded product. This 5wt.% was based on the 94UL standard.

[0040] The "resin molded product" in the above claims refers to a molded product made of a resin whose main component is a thermoplastic resin, which contains reinforcing agents such as inorganic and organic substances, and other additives. The term "said mold device" refers to a sealing mold, a blow molding mold, or a pressure molding mold for implementing the GCP described in this invention. The term "molding equipment" refers to the injection molding machine, extrusion molding machine, blow molding, and compressed air molding equipment described in this invention, such as nitrogen gas separation equipment, gas compression equipment, gas injection equipment, and GCP equipment.

[0041] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] (Definition of terms) First, the terms used in the present invention are defined. The term "process" refers to the flow of work or the process. One process consists of multiple operations and procedures, and generally indicates a large framework. In other words, a process is a term that indicates dividing the progress and procedures of things and work step by step, and is a process of sequentially performing a series of operations necessary to achieve a certain goal. Also, "process" has a meaning in the order and progress of work. The "work" in "process" indicates the work of creating something, and the "procedure" indicates the path or the course.

[0043] The term "mold cavity" refers to the space filled with a resin having foamability or / and a non-foamable resin in injection molding, block molding, or casting molding. Also, "inside the cavity" refers to the inside, space, or volume of the mold cavity. The term "cavity" is a synonym for "mold space". In fact, in injection molding, when the first mold (generally indicating the fixed-side mold) and the second mold (generally indicating the movable-side mold) are combined, the space defined by the first mold and the second mold is formed. This space is the space filled with a foamable resin or / and a non-foamable resin, and is sometimes simply referred to as the "cavity". The ejector pin mainly refers to the ejector pin provided on the second mold, but in addition, it also includes inclined pins of slide cores, kicker pins, etc.

[0044] In addition to the injection molding exemplified above, the present invention can also be implemented by die devising in sheet extrusion (extrusion), profile extrusion molding, blow molding, etc.

[0045] The term "injection" refers to filling, injecting, or the process of filling the mold cavity with a resin having foamability or / and a non-foamable resin. The term "extrusion" refers to continuously performing extrusion molding of a heat-melted foamable resin or / and a non-foamable resin through a die. This includes a method of mixing a non-foaming resin and a foaming resin in the extruder nozzle (mixing them together and calling it mixed) to give them foamability, and a method like the Niho Method of mixing a liquid, and if necessary a gas, with the heated and molten resin in the extruder nozzle to give them foamability. Of course, the Niho Method is also an effective method for injection foam molding.

[0046] "Blow" refers to the technique of placing a parison in a mold and pressurizing it with air or other gas from inside the parison to form it. If the parison is made of foam resin, this is blow molding using foam resin.

[0047] "Filling" refers to filling the mold cavity with foamed resin and / or non-foamed resin in processes such as injection molding and block molding. Filling an amount less than the volume of the mold cavity is called a short shot or short mold, filling an amount equal to the volume is called a full shot or full pack, and filling an amount greater than the volume is called an overshot or overpack. In order to reduce sink marks or improve transferability (UP, UP, Up), if pressure is applied to the resin from the molding machine heater barrel after the full shot, this invention clearly indicates that pressure is used. In the case of block molding, the distinction between non-pressurized and pressurized is made clear, such as non-pressurized after filling and pressurized after filling. "Pressurization" refers to applying a fluid pressurized to the resin at atmospheric pressure or higher.

[0048] "Resin in the heating cylinder" refers to thermoplastic resin in a solid (solid) state such as pellets, bulk, or powder before being heated and melted, in the middle of being plasticized, or in a molten state after plasticization is complete.

[0049] The properties of "foaming agents" can be gas, liquid, or solid, and are broadly classified into physical and chemical foaming agents, each of which can be inorganic or organic. Gases include inert gases such as nitrogen gas, carbon dioxide (CO2), rare gases such as helium and argon, and flammable gases such as hydrogen, and these are used alone or as mixed gases (mixed fluids). Liquid foaming agents refer to substances that are liquid at NTP (Natural Temperature Pressure, Natural Temperature and Pressure, Normal Temperature Pressure, Normal Temperature and Pressure = temperature of 23°C and pressure of 1 atmosphere (1 atm, 760 mmHg)), and include monohydric alcohols such as ethanol (EtOH) and propanol (mainly isopropanol, iso-PrOH in this invention), dihydric or higher alcohols, ethers, esters, ketones, etc., vaporizable substances such as distilled water, ion-exchanged water, city water (tap water), and well water, sodium bicarbonate water, sodium citrate water, etc. that use these substances as solvents, and liquefied carbon dioxide gas (liquid carbon dioxide) liquefied by pressurization and cooling, etc. Solids include inorganic thermal decomposition types of chemical foaming agents such as hydrogen carbonates, carbonates, nitrites, hydrogen compounds, carboxylic acids, and carboxylates. Microballoons (macroballoons, microballoons) such as Advancel (trade name), copper sulfate containing structural water {copper sulfate pentahydrate, (now called "hydrate" rather than the concept of "crystal water"), of course, these 5 moles of structural water also vaporize in the heating cylinder at the temperature of the heating cylinder and the temperature of the molten resin heated and melted, and the water vapor acts as a foaming gas.}, silica gel soaked in water to be hydrated, ABS soaked in water for a long time, for example about 6 hours, and the surface moisture is removed by centrifugation or the like to be hydrated (ABS), PC and PC-based resins (PC / ABS in this case) soaked in water like ABS, and soaked in water to be hydrated can also be used as foaming agents because the moisture vaporizes in the heating cylinder like the structural water and functions as a foaming agent. These are examples of water, but it is not limited to water, and organic solvents such as alcohol may also be used.Although it is an extreme example, rice that has been soaked in water to absorb moisture can also be used as a foaming agent. Of course, solid carbon dioxide (dry ice) is also a solid foaming agent. When dry ice is mixed with pellets and placed in a hopper and then in the heating cylinder, the dry ice vaporizes immediately and the vaporized carbon dioxide escapes from the hopper, so a plug (such as a back melter) must be placed in the hopper during plasticization and measurement to prevent the carbon dioxide from escaping. Alternatively, a preferred method is to drill a hole in the heating cylinder and use a mechanism such as a feed screw to measure the amount and steadily add a fixed amount to the molten resin.

[0050] Inorganic thermal decomposition type blowing agents include hydrogen carbonates and carbonates such as sodium hydrogen carbonate, potassium hydrogen carbonate, and lithium hydrogen carbonate (Li) as mentioned above, while organic thermal decomposition type blowing agents include azo compounds, hydrazine derivatives, semicarbazide compounds, azide compounds, nitroso compounds, and triazole compounds, and reactive types include isocyanate compounds. Examples include ADCA {azo di(di) carboxylic acid amide}, HDCA (hydro dicarboxylic acid amide), azo dicarboxylate (ADCA Ba salt), HDCA Ba salt, DPT (dinitroso pentamethylenetetramine), OBSH {P-P'-oxybis(benzenesulfonylhydrazide)}, and AIBN (azo bis isobutyronitrile) (listed above). Details of blowing agents and foam molding are described in Various Polymers and Foam Molding Technology, published by the Technical Information Association in August 1993. In the case of carbonates or bicarbonates (alkali metals or alkaline earth metals), an equivalent amount (neutralization reaction with a basic carbonate or bicarbonate) of a weakly acidic substance such as citric acid or disodium citrate may be used in combination.

[0051] When using a liquid as a foaming agent for thermoplastic resin, the optimal volume (vol.) for the weight (wt.) of the molded product is measured (weighed) and injected into the thermoplastic resin in the heating barrel all at once or continuously, and vaporized or / and thermally decomposed or / and chemically reacted depending on the temperature of the heating barrel and inside the heating barrel, the temperature of the molten thermoplastic resin in the heating barrel, or / and the temperature of the nozzle, or / and the temperature of the mold, to generate a foaming gas useful (effective) for foam molding. The temperature of the liquid to be injected is room temperature, but it may be heated if necessary to shorten the time until vaporization. The pressure of the liquid may be increased to a level higher than the pressure that can be injected into the heating barrel, raising the boiling point before injection.

[0052] The generated gas is finely dispersed and / or pressurized and dissolved in the molten resin in the heated barrel by the physical force of the metering stage and the physical force of the filling stage, and the thermoplastic resin in the heated barrel becomes a foamable thermoplastic resin. This can be filled into the mold cavity to produce a molded product with a foamed structure. In other words, "foam molding" refers to the process of obtaining a foamed structure by filling a mold with resin that has been given foamability by dispersing and / or dissolving (including pressurized dissolving) a foaming gas into the resin in the heated barrel. Note that in the case of extrusion, a die is used instead of a mold.

[0053] "Giving foamability to molten resin" means that in the case of gas {gas (e.g. nitrogen gas)}, large lumps of foaming gas (nitrogen gas) are dispersed by the force of screw rotation, and pressurized melting by back pressure, or / and finely dispersed in molten resin. In the case of liquid, foaming gas is generated by vaporization, thermal decomposition, etc. depending on the temperature inside the heating cylinder and the temperature of the molten resin, and the foaming gas is dispersed by the force of screw rotation, and pressurized melting by back pressure, or / and finely dispersed in molten resin. In the case of solid foaming agents, it means that foaming gas generated by chemical reaction is dispersed by the force of screw rotation, and pressurized melting by back pressure, or / and finely dispersed in molten resin. In the case of micro (macro, micro) balloons, it also means that the generated foaming gas is dispersed by the force of screw rotation, and pressurized melting by back pressure, or / and finely dispersed in molten resin. It is desirable for the screw to have a high rotation torque and a high rotation speed. Increasing the back pressure improves the mixing ability and the dispersion of the foaming gas. This includes cases where the nozzle has an inlet for the gas foaming agent, an inlet for the liquid foaming agent, and where the heated and melted foamable resin is mixed with the non-foamable resin. If necessary, the screw may have a dulmage or the like.

[0054] The liquid injection port is preferably located 2D (twice the screw diameter) to 6D (six times the screw diameter) from the tip of the screw, not including the screw head, but the liquid can be injected at any other position, 2D or less, or even behind 6D, to impart foamability to the molten resin in the heating barrel. Depending on the combination of resin and liquid, an injection port can be provided in the nozzle and the liquid can be injected at the time of injection, causing the liquid to penetrate into the molten resin due to the injection pressure and impart foamability to the molten resin. In this case, it is advisable to provide a mixing nozzle or the like and inject the liquid from the rear of the mixing nozzle (53rd embodiment).

[0055] "Foaming" refers to the state where the foaming gas is suppressed by external pressure, such as the GCP (outer GCP), back pressure, injection pressure, etc. (compressed into the resin and finely dispersed in a small volume, or / and pressurized and dissolved), and the volume of the foaming gas in the resin increases, or / and the foaming gas that was pressurized and dissolved becomes gas, when the external pressure is reduced or eliminated. "Foaming" also refers to the process in which a foamable thermoplastic resin is extruded from a heating cylinder and foams, or the process in which a foaming gas is generated by the vaporization, thermal decomposition, or chemical reaction of a liquid or solid foaming agent.

[0056] "Foaming" refers to the process of finely dispersing and / or pressurizing and dissolving foaming gas in a molten thermoplastic resin, and then lowering the pressure to form foam cells inside and / or on the surface of the thermoplastic resin {The foam cells (bubbles) that appear on the surface are swirl marks.} In the case of thermosetting resins, the foaming agent is heated, vaporized, thermally decomposed, and chemically reacts to generate foaming gas, which forms foam cells inside and / or on the surface of the thermosetting resin. Molded products with foam layers inside and / or outside due to foaming in this way are called foam molded products or foam structures.

[0057] "Foamable resin" refers to a thermoplastic resin or thermosetting resin in a molten state in which a foaming gas useful for foam molding has been finely dispersed and / or dissolved under pressure. In other words, "foamable resin" refers to a thermoplastic resin or thermosetting resin containing a gaseous foaming agent, a liquid foaming agent, or a solid foaming agent. In the present invention, the state of the resin is described as "a thermoplastic resin having foamability in a molten state," "a thermoplastic resin containing a foaming agent, or a thermosetting resin containing a foaming agent," and the state of the resin is described as accurately as possible, such as the fact that the resin has foamability, that the resin contains a gaseous foaming agent, a liquid foaming agent, or a solid foaming agent. Note that the foaming agent may be a combination of liquid and solid, a combination of gas and solid, or several types of gas alone. In the case of a liquid, a mixture of alcohol and water may be used.

[0058] "Foam-molded products" refer to resin-molded products that have discontinuous foam cells inside, and are produced by molding foamable thermoplastic resins or thermosetting resins. The average size of the foam cells is 5,000 μm {microns (μ), micrometers (μm)} or less. In the present invention, foam-molded products are also considered to be foam-molded products when hollow parts and foam cells are mixed in a hollow molding process using foamable resins.

[0059] "Combined use" also refers to using or combining something with another thing. For example, one molding process method can be effective, but it can also be used in combination with another method, creating a synergistic effect or improving one or / and both effects. Foaming agents may also be used in combination with several types rather than alone. Liquid, gaseous, and solid foaming agents may also be used in combination.

[0060] "Foaming assistant" refers to a substance used to lower the decomposition temperature of the foaming agent or to promote the decomposition of the foaming agent. Examples of foaming assistants for organic foaming agents include zinc stearate, barium stearate, metal soap, urea (which has the effect of lowering the decomposition temperature of ADCA), zinc oxide, etc. Inorganic and organic acids (such as citric acid and sodium hydrogen citrate) used to decompose carbonates and hydrogen carbonates can also be considered foaming assistants. However, in the case of PC-based resins, there is a risk of decomposition, so it is necessary to check in advance whether the physical properties will be reduced by adding each substance. In particular, basic oxides (another word for metal oxides) such as CaO, BaO, and Cs2O have a high risk of decomposing the PC in PC-based resins.

[0061] (Foam nucleating agent for PC resins, foam nucleating agent) "Foaming (foaming) nucleating agents, bubble nucleating agents" are substances that are mixed with the resin and foaming agent to be molded in order to form fine foam cells. Foaming nucleating agents utilize the difference in specific heat between the molten resin and the foaming nucleating agent to create small sinks (spaces) at the boundary between the molten resin and the foaming nucleating agent, and foaming begins with these sinks as nuclei (the sinks = the starting point where foaming gas gathers in a small space and foaming gas gathers and foaming begins), forming foam cells. In this way, foaming nucleating agents utilize temperature differences {(differences in specific heat, differences in the rate of heating, differences in the rate of cooling) (when the foaming nucleating agent is heated, its temperature becomes higher than the surrounding molten resin, or conversely, when it becomes lower)} to bring about the action and effect of finely dividing foam cells. Examples of foam nucleating agents include metal powders such as aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), iron (Fe), copper (Cu), silver (Ag), W (tungsten), and Cr (chromium), non-metal powders such as silicon (Si) and germanium (Ge), and oxides, nitrides, and carbides of these metals.

[0062] In addition, flame retardants can also be foam nucleating agents, and provide the action and effect of foam nucleating agents. Halogen-based flame retardants, such as brominated epoxy, phosphate-based flame retardants, such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl di-2,6-xylenyl phosphate, non-halogen phosphate esters, such as DAIGUARD-1000 (trade name) and aromatic condensed phosphate esters, such as CR-7335 (trade name), CR-741 (trade name), and aromatic condensed phosphate esters, such as PX-200 (trade name). Examples of such phosphate esters include non-halogen phosphate esters represented by {TMCPP (trade name)} and tris(tribrimoneopentyl) phosphate {CR-900 (trade name)}, halogen-containing phosphate esters represented by {CR-504L (trade name)}, {CR-570 (trade name)}, and {DAIGUARD-540 (trade name)}, and non-halogen condensed phosphate esters represented by {DAIGUARD-580 (trade name)}, {DAIGUARD-880 (trade name)}, and {DAIGUARD-850 (trade name)}.

[0063] In addition, fine particles of fluorine-containing resins such as polytetrafluoroethylene (tetrafluoride) (abbreviation: PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (abbreviation: PFA), tetrafluoroethylene-hexafluoropropylene copolymer (4.6-fluoride) (abbreviation: FEP), tetrafluoroethylene-ethylene copolymer (abbreviation: ETFE), polyvinylidene fluoride (difluoride) (abbreviation: PVDF), polychlorotrifluoroethylene (trifluoride) (abbreviation: PCTFE), and chlorotrifluoroethylene-ethylene copolymer (abbreviation: ECTFE), which are used in combination with the above flame retardants, also act as foam nucleating agents. Metal particles with nano-sized particles also act as foam nucleating agents.

[0064] For example, when water is used as a blowing agent, the foam cells are smaller in ABS than in AS. When comparing PS and HIPS, the foam cells are smaller in HIPS, just like ABS. This is because the rubber (graft rubber) made by graft copolymerizing acrylonitrile and styrene with butadiene blended in the resin has an island-sea structure dotted like islands in a sea of ​​AS, and this graft rubber acts as a foam nucleating agent. It has been confirmed that the foam cells are smaller with PC / ABS than with PC alone. This is because the specific heat of each polymer is different, and minute contractions occur at the interface and boundary regions, resulting in the action and effect of the foam nucleating agent. The above foam nucleating agents can be used alone, or two or more types can be mixed together as necessary.

[0065] A foaming agent useful for foam molding of PC resin is a gas such as nitrogen gas or carbon dioxide gas that is injected into the heating barrel during metering to impart foamability to the plasticized and melted molten resin in the heating barrel. Similarly to the gas, water is introduced into the heating barrel and vaporized by the heat (thermal energy, temperature) of the heating barrel and / or the heat (thermal energy, temperature) of the molten resin that has been heated and melted, and then finely dispersed in the molten resin in the heating barrel to impart foamability. As mentioned above, foam nucleating agents can be used alone or in combination of two or more types.

[0066] In the case of PC resin, the foam nucleating agent may act as a catalyst to accelerate the decomposition of PC resin, or the foam nucleating agent itself may decompose the PC resin. In particular, when water is used to foam PC resin, a substance that does not hydrolyze PC resin is selected.

[0067] Examples of useful foam nucleating agents in the foam molding of PC resin include light diffusing agents such as silver oxide, aluminum oxide, silicon dioxide, and silicon carbide, which do not decompose PC and do not cause a decrease in physical properties. As a result of extensive research by the inventors, the content ratio of the components in the foam nucleating agent of the present invention is preferably 40 to 60 parts by weight of aluminum oxide, 20 to 40 parts by weight of silver oxide, 1 to 10 parts by weight of silicon dioxide, and 1 to 10 parts by weight of silicon carbide. The particle size of the components other than silver oxide is preferably 30 μm or less in order to be blended with PC resin. If it exceeds 30 μm, it cannot be uniformly dispersed in the resin and sufficient light diffusing effect cannot be obtained, which is not preferable. More preferably, it is 100 nm to 10 μm. These components may be commercially available or may be synthesized to any particle size. Also, those with a large particle size may be crushed. The synthesis method is not particularly limited.

[0068] Silver oxide is useful as a foam nucleating agent for PC resins, and promising alternatives to silver oxide include Cu2O, ZnO, Al2O3, MgO, TiO2, ZrO2, V2O3, V2O5, tungsten oxide, FeO, Fe2O3, manganese oxide, chromium oxide, cobalt oxide, nickel oxide, In oxide, indium (In) tin (Ti) oxide, germanium oxide, tin oxide, lead oxide, corundum, carborundum, Al2O3·MgO (spinel), WC (tungsten carbide), TiN (titanium nitride), and CrN (chromium nitride).

[0069] On the other hand, for example, carbonates such as calcium carbonate (Ca), magnesium carbonate (Mg), and barium carbonate (Ba), sulfates such as calcium sulfate and barium sulfate, and alkali metal salts of organic acids, especially monosodium dihydrogen citrate and monopotassium dihydrogen citrate, act as effective foam nucleating agents, but there is concern about the decomposition of PC. Helical D (a calcium-containing inorganic filler made by Shiraishi Calcium) also acts as a foam nucleating agent. The above foaming assistants such as zinc stearate, barium stearate, and metal soaps also act as foam nucleating agents. Glass fiber, glass beads, carbon fiber, carbon powders such as Ketjen Black and Acetylene Black, and carbon nanotubes (CNTs) also act as foam nucleating agents. Metal powders are also acceptable. Nanomaterials from Adachi Shinsangyo Co., Ltd. can also be used as foam nucleating agents. Resin additives, such as pigments, also act as foam nucleating agents.

[0070] {Particle size of foam nucleating agent (particle size)} If the particle size of the foam nucleating agent is fine, it can be uniformly dispersed in the resin and the size of the foam cells can be made uniform. Although it depends on the foam nucleating agent used, it is generally 250 μm (micrometer, micron) or less, preferably 100 μm or less, and considering uniform dispersion, 50 μm or less is preferable. Even finer particles of 100 nm (nanometer) to 10 μm are better.

[0071] (Use of foam nucleating agents) The foam nucleating agent used may be one type (single), or two or more types may be mixed together (composite use). The particle size may also be the same, or even if a single type is used, different particle sizes may be used. When using multiple types, the particle sizes of the foam nucleating agents may be the same or different.

[0072] (Master batch of foam nucleating agent) Useful foam nucleating agents for use in foam molding of PC resins include metal oxides and metal carbides. These foam nucleating agents are mixed (dispersed) in the resin before use, but if the foaming agent is liquid, it is mixed with the liquid before use. A foam nucleating agent with a high concentration (content of foam nucleating agent) may be produced in the pellets of the resin to be foamed and used as a master batch. When there are several types of foam nucleating agents, each of them (meaning one type of substance in this invention) may be made into a master batch of foam nucleating agent, and the master batch of each foam nucleating agent may be mixed with the pellets of the resin to be foamed and used. A master batch of foam nucleating agent may be produced by heating and melting and kneading (for example, melting and kneading using an extruder, or pelletizing using a pelletizer), but a master batch of foam nucleating agent can also be produced by supporting it on the surface of the pellets of the resin to be foamed as described in PCT / JP2020 / 15536.

[0073] "Mix ratio" is expressed as the ratio of the weight (wt.) or volume (vol.) of the foam nucleating agent master batch to the weight or volume of the resin to be molded, assuming that the weight (wt.) or volume (vol.) of the foam nucleating agent master batch is 1. It is expressed as the ratio (weight ratio) of the foam nucleating agent master batch contained in the resin to be foam molded (weight is generally used). For example, it is 2 wt. (weight)% or 2 vol. (volume, volume)% relative to the resin. It is expressed as 2:100 (or 1:50, or 1 / 50), or 2 wt.%, 2 vol.%, etc. When a liquid foaming agent is used, it is expressed as the volume (vol.) relative to the weight (wt.) or volume of the resin.

[0074] (Amount of foam nucleating agent added) The amount of foaming nucleating agent added can be within the range that does not affect the physical properties of the resin and allows for acceptable deterioration of the physical properties. The amount added varies depending on the resin to be foamed and also on the foaming gas that imparts foaming (for example, nitrogen gas or carbon dioxide gas may be used alone, or a composite gas may be made by mixing the various foaming gases, such as nitrogen gas, carbon monoxide, carbon dioxide gas, and water vapor). The amount of foam nucleating agent to be added to the resin to be foamed is 0.001 to 10 parts by weight per 100 parts by weight of resin. If the amount of foam nucleating agent is less than 0.001 part by weight, the particle size of the foam cells will be large. On the other hand, if the amount of foam nucleating agent added is large, the foam cells will become finer and the foaming power will be strong. In order to eliminate the swirl marks that occur on the surface of the GCP and obtain a foam molded product with a clean surface and smooth appearance, the type and pressure of the gas used (the inventor uses air at a pressure of 1.4 MPa, taking into consideration economical reasons and ease of foam molding) is generally changed. It is possible to suppress swirl marks by increasing the pressure of the GCP. If carbon dioxide gas is used instead of air, the carbon dioxide gas will dissolve into the flow front of the molten resin to which foaming properties have been added and the swirl marks will be reduced. For reference, GCP using carbon dioxide gas will produce a clean surface even in the case of non-foaming resin. Composite materials such as glass fiber also have the effect of sinking the glass fiber.

[0075] [Polycarbonate resin, polycarbonate ester {polycarbonate (PC)}] The PC used in the present invention will be described below. PC is a polycarbonate produced using bisphenol A and phosgene or di(di)phenyl carbonate as raw materials. When carbonyl chloride is used, it is polymerized by interfacial condensation polymerization. When diphenyl carbonate is used, it is synthesized by polymerization through ester exchange. There are no particular limitations on the PC, and any known resin can be used. For example, a resin obtained by reacting an aromatic dihydroxy compound with phosgene or a carbonate diester by a melting method or solution method can be used. Representative examples of aromatic dihydroxy compounds include 2,2-bis(4-hydroxyphenyl)propane (=bisphenol A), 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)sulfide, and bis(4-hydroxyphenyl)sulfone. Among these, bisphenol A is particularly preferred and is widely used. In the present invention, in addition to the widely used bisphenol A-based PC, PC produced using other dihydric phenols can also be used.

[0076] Furthermore, trivalent or higher phenolic compounds such as those shown below may be used in combination. Trivalent or higher phenolic compounds include phloroglucin, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene, 2,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane, and 2,2-bis-[4,4-(4,4-dihydroxydiphenyl)-cyclohexyl]-propane.

[0077] The viscosity average molecular weight of the PC used in the present invention is 1,000 to 100,000. More preferably, it is 10,000 to 50,000. When producing such PC, a molecular weight regulator, a catalyst, etc. can be used as necessary. The PC resin may be used alone or in a suitable mixture of two or more kinds.

[0078] (Regarding the production of PC resin compositions) The method for producing the PC resin composition containing the foam nucleating agent of the present invention is not particularly limited, but a preferred method for producing the resin composition of the present invention is a method of melt-kneading each component using a multi-screw extruder such as a twin-screw extruder. A representative example of a twin-screw extruder is ZSK (trade name, manufactured by Werner and Pfleiderer). Specific examples of similar types include TEX {trade name, manufactured by Japan Steel Works, Ltd.}, TEM {trade name, manufactured by Toshiba Machine Co., Ltd.}, and KTX {trade name, manufactured by Kobe Steel, Ltd.}. Other specific examples include melt-kneaders such as FCM (trade name, manufactured by Farrel), Ko-Kneader (trade name, manufactured by Buss), and DSM (trade name, manufactured by Krauss-Maffei).

[0079] (Purpose and meaning of foaming PC resin) PC is a resin whose impact strength is highly dependent on thickness. For example, the impact strength of solid (general, general) molded products with a thickness of 5mm or 6mm is lower than that of ABS. However, if the thickness is reduced to 1mm or 2mm, the impact strength becomes extremely high. It has been confirmed that if 0.2mm PC is laminated, it will not break even if a large impact is applied. If this is the case, it is possible to obtain a PC foam structure with sufficient impact strength by foaming it using water, which does not affect the physical properties of PC, as a foaming agent, making an expanded core such as a mold back or core back, increasing the foaming ratio and forming thin PC foam cells on the surface and inside. This is the purpose of the foaming molding of PC and resins mainly composed of PC described in this invention. PC is often used in polymer alloys with other resins, such as ABS, but in this case, PC also has a thin layer in the ABS, so it is possible to use water as a foaming agent for foaming molding of PC / ABS, PC / PS, PC / HIPS, etc.

[0080] (Method of increasing the expansion ratio of PC resin) Water is used as the foaming agent, and the resin that has been given foaming properties in the heating cylinder of the molding machine is filled into the cavity. After filling, the mold is moved back a predetermined distance (generally the movable mold is moved back. In other words, the PL is opened a predetermined distance). The detailed process is shown below. The mold is closed, and the foamable resin is filled into the cavity. The mold is opened a predetermined distance at the same time as filling, or with a slight delay after filling. At this time, the molded product expands due to the foaming force of the foamable resin. In addition, when the inside is made hollow (inner GCP) {in hollow molding using foamable resin, high-pressure nitrogen gas or the like is injected from the nozzle of the molding machine, or / and from the runner, or / and directly into the molded product, and the inside is expanded by the force of the fluid} {especially in the core-back shown in Figures 11, 12, 13, and 14, the PL is vertically cut off, so there is little flash even if the mold is opened widely. However, when the expansion ratio is extremely increased to 2, 5, or 10 times, the foaming power alone is not enough to transfer the foam to the mold, and if the foam is cored back as it is, the molded product will separate from the mold, and the mold reproducibility will decrease. As a result, a foamed product with a high expansion ratio cannot be obtained. In foam molding using an outer GCP, the mold reproducibility is further decreased, so a foamed product with a high expansion ratio and a clean, smooth surface cannot be obtained. To solve this problem, the inventor also performed hollow molding (inner GCP) using a foamable resin and confirmed that sufficient mold reproducibility was obtained. It was also confirmed that a foamed product with a clean, smooth surface and a high expansion ratio can be obtained by using an outer GCP to perform hollow molding (inner GCP) on a foamable resin, followed by mold backing and core backing. Once cooling and solidification is complete, a pressurized fluid (also called a "high pressure fluid" or "compressed fluid") is placed inside the molded product. Generally, gas compressed to above atmospheric pressure is used, but liquid can also be used. The main gases are air, nitrogen, and carbon dioxide, either alone or in combination. The main liquid is water, but it can also be used at higher temperatures, such as 40°C, 50°C, 90°C, and even 100°C, where the pressure is high enough that it can remain liquid.), the pressurized fluid is exhausted, the pressure is lowered to a level where the internal pressure will not cause the foam to expand or burst, and the mold is opened to remove the foam molded product. At this time, in a three-plate mold, if the PL is opened a certain distance in advance, the stripper plate will not open even if the PL is opened as is, and the spool runner cannot be removed, so the mold must incorporate a mechanism that allows the stripper plate to open later, even if the PL is opened first. Furthermore, the software that controls the mold back and core back can be implemented by exchanging signals with the molding machine using an external sequencer (PLC, a controller box using a PLC), or the software that performs these operations can be added (written) to a PLC (a PLC with programs written into it that control opening and closing the mold, injection, etc.) built into the molding machine.

[0081] The method for feeding the foam nucleating agent and the PC resin of the present invention to the extruder is not particularly limited, but the following method is a typical example. (1) A method in which the foam nucleating agent of the present invention and a PC resin are supplied independently to an extruder. (2) A method in which the foam nucleating agent of the present invention and the PC resin additive are premixed in a mixer such as a super mixer, and then the mixture is fed to an extruder.

[0082] The method is not limited to the above, and a resin may be produced after mixing an arbitrary amount of the foam nucleating agent with the raw material PC. The method for producing the PC resin composition is not limited at all. The PC resin composition containing the foam nucleating agent of the present invention can also be used for foam molding in the form of various profile extrusion molded products, sheets, films, etc. by extrusion molding. Furthermore, it can be molded into a heat shrink tube by applying a specific stretching operation. Furthermore, it can be molded into a molded product by rotational molding or blow molding. It can also be molded from flame-retardant PC resin compositions (resins made flame-retardant by adding flame retardants and flame retardant assistants) and resins with added minerals such as glass fiber to increase rigidity. These molded products can also be subjected to various surface treatments such as painting and plating.

[0083] Among PC-based resins, polymer alloys and polymer blends that contain PC as the main component include PC / PET (polyethylene terephthalate), PC / PBT (polybutylene terephthalate), PC / ABS (acrylic-nitrile-styrene graft terpolymer in which acrylic-nitrile and styrene are graft copolymerized onto butadiene, and AS (copolymer of acrylic-nitrile and styrene)), PC / AES, PC / AAS, PC / ASA, PC / PS (polystyrene), PC / PP (polypropylene, polymethylvinyl), PC / PE (polyethylene, polyvinyl hydrogen), PC / vinyl chloride (polyvinyl chloride, PVC), and PC / PPO. In foam molding, if the foam nucleating agent is not selected correctly, the original physical properties of PC will not be exhibited. Water is a useful blowing agent for foam molding of PC resins, but when PET or PBT is included in a polymer alloy or polymer blend mainly composed of PC, the ester resins such as PET decompose and the physical properties decrease significantly. In the case of polyamide (PA), hydrolysis hardly occurs at all.

[0084] "Compatibility" refers to the property of thermoplastic resins to mix at the molecular level when each resin is heated and melted; for example, AS is compatible with ABS, and PS (polystyrene) and HIPS (high impact polystyrene) are compatible with PPO (polyphenylene oxide) and PPE (polyphenylene ether). In this invention, PPO and PPE are treated as the same substance and referred to as "PPO." PPO that is modified or denatured (mixed to form a blended polymer or polymer alloy) with HIPS and / or PS, as well as PP, ABS, and PA, is called modified-PPO, modified-PPO, or m-PPO.

[0085] "Compatibility" refers to a situation where one resin is not compatible with the other and is dispersed in the other, forming an island structure or other structure. For example, rubber B in ABS {a polymer (polymer) in which butadiene rubber is graft-copolymerized with acrylonitrile (vinyl cyanide) and styrene (vinyl phenylate)} shows compatibility with AS. When they are compatible, there is no or only a small decrease in physical properties.

[0086] {Compatibilizer} When manufacturing polymer alloys and polymer blends, such as PC / PET, PC / PBT, PC / AS, PC / ABS, PC / PS, and PC / HIPS, which have PC as the main component, a compatibilizer is used as necessary. Examples of compatibilizers used for these purposes include those sold by Nippon Oil & Fats. If the amount of compatibilizer added is small, the resin will not be compatible (miscible) enough and the physical and chemical properties of the resin will not be fully exhibited. If too much is added, the physical properties will decrease significantly, so it is desirable to add an amount that has little effect on the physical properties relative to the weight of the PC.

[0087] (Suitable for painting) In the case of PC resin molded products, if the internal stress (internal distortion) is high, the paint solvent (thinner) will cause microcracks and the high impact strength of PC will not be exhibited. In the foam molding of this invention, the molding is a cut-off molding that does not use a dwell pressure as in the case of injection molding, so there is little internal stress. Even if painting is applied in this state, there will be less deterioration in physical properties due to cracking than in molded products with high internal stress caused by high dwell pressure. If the product is further annealed for about 2 hours to remove the internal stress, the deterioration in physical properties (such as cracking) due to microcracks will be further reduced.

[0088] (Example of foam molding of PC resin) When performing foam molding of PC-based resins, as is clear from Comparative Example 1 (foaming agent used was sodium bicarbonate), Comparative Example 2 (foaming agent used was ADCA), and Comparative Example 3 (foaming agent used was ethanol) described below, the properties of PC (high impact strength = does not break easily) are not exhibited at all in the foam molding of PC. However, as shown in Example 1, it was confirmed that if water (chemical name is "hydrogen oxide, dihydrogen monoxide", chemical formula is "H2O") is used as the foaming agent, the deterioration of the physical properties of PC is small.

[0089] (Outer GCP) Using water as the foaming agent, water was injected into the heating barrel of the injection molding machine through the liquid injection device and the injection port on the heating barrel shown in Fig. 1, Fig. 4, and Fig. 5 of PCT / JP2015 / 062611 to perform foam molding. Swirl marks due to the water foaming agent were generated on the surface of the foam molded product. When GCP was performed using 1.4 MPa air and the nozzle shown in Fig. 20 to Fig. 22 of PCT / JP2015 / 062611, the sealed mold for GCP shown in Fig. 23 and Fig. 25, and the GCP device shown in Fig. 24, it was confirmed that it was possible to produce foam molded products that had no swirl marks on the surface, had a clean, smooth skin layer, and had a fine foam layer inside.

[0090] (Undercut Treatment) When the molded product has an undercut (protruding part) shape as shown in Figures 17 and 18, a mechanical slide using a slide core (outer slide core method), tilted core method (tilt pin), hydraulics, pneumatics, rack and pinion, ball screw, etc. is used. In Figure 17, reference number 57 indicates the undercut part, and the arrow at reference number 58 indicates the slide direction. In this case, an angular pin is used, and by linking the opening and closing of the mold with the opening and closing of the slide, it is possible to process the undercut (processing molded products with undercut shapes). Since the amount of movement of the slide is determined by the angle of the angular pin, in some cases a new part such as a slide stopper that stops the slide from going down too far is installed. If the undercut portion indicated by reference number 57 (shown as a hole in Fig. 17) is long, a slide core using hydraulics or the like is used. Reference number 55 indicates the cross section of the product (cross section of the cavity), and 61 is the PL of the mold (the parting surface, parting portion, the surface where the movable side mold and the fixed side mold come together, the space defined by the joining of the fixed side mold and the movable side mold is the "cavity").

[0091] In the case of Fig. 18, the undercut treatment of reference number 59 is mainly performed by the inclined core method. Reference number 60 indicates the direction of the slide. Reference number 56 indicates the cross section of the product, and reference number 61 is the PL of the mold.

[0092] (Sealing mold) First, we will explain the structure of the sealing mold for GCP, which is an effective means of eliminating the swirl marks that occur on the surface during foam molding used in this invention and obtaining foam molded products with a smooth surface. There are two types of sealing mold structures: one that surrounds the ejector mechanism with a spacer block (mold structure), and one that seals each ejector pin with an L-shaped, U-shaped weighted O-ring, or a U-shaped (concave) O-ring (mold structure). Figure 19 shows the structure of a sealing mold using an ejector box, in which the spacer block (74) is integrated into a single structure shaped like the Japanese katakana character "ro" and houses and seals the ejector mechanism. Reference number 62 is a spool bush, which is sealed with an O-ring (64). Reference number 63 is a mounting plate on the fixed (cavity) side, and an O-ring 65 is installed between the mounting plate and the fixed mold plate (104) to seal. Reference number 89 is a fixed side insert that forms a cavity, reference number 61 is a PL, and an O-ring (69) is placed (installed) on the PL. Reference numbers 55 and 56 are cavities that are filled with molten resin. Reference number 70 is a movable (core) mold plate, in which an insert (92) is installed. The insert is fixed by bolts (not shown) or the like. The pressurized air and pressurized fluid in the cavity also enter and exit through the gap (the mating surface) of the insert (92). Reference number 87 is a receiving plate. Reference number 72 is an O-ring that seals between the movable mold plate (reference number 70) and reference number 87, reference number 73 is an O-ring that seals the gap between reference number 87 and reference number 74 (a spacer block processed into the shape of the Japanese katakana character "ロ" to enclose and seal the ejector mechanism), which completes reference number 75, an ejector box structure (a mold structure that encloses the ejector mechanism in a space for sealing purposes). Since the ejector pins are sealed by the ejector box, there is no need to seal each of the ejector pins (reference number 67). Reference number 76 is an ejector plate (upper) that fixes the ejector pins, and reference number 77 is an ejector plate (lower) that fixes the ejector pins. Reference number 80 is a mounting plate on the movable side, and reference number 79 is an O-ring installed in the gap between reference number 80 and reference number 74. Reference number 82 is an ejector rod hole, and an O-ring indicated by reference number 81 is assembled at the bottom of reference number 77 to seal when the mold is closed and the ejector plate is moved back by a return pin (not shown) or the like.

[0093] The O-rings with numbers 64, 65, 69, 72, 73, 79, and 81 are commercially available and are made of NBR (nitrile butadiene rubber), silicone rubber, urethane rubber, etc. These O-rings are used by carving a groove into which they are fitted, but there is a risk that the surfaces fixing the O-rings with numbers 69 and 81 will come apart when the mold is opened and the molded product is extruded, resulting in the O-ring coming out of the groove. Therefore, the inventor has devised a tapered end mill to make the grooves with numbers 69 and 81 into dovetail grooves (shapes in which the top is narrower than the bottom in cross section) so that the O-rings will not come out of the groove even if the plate comes apart.

[0094] Next, the gas circuit for pressurizing the inside of the mold {mainly air compressed to atmospheric pressure or higher is used, but in some cases nitrogen gas, carbon dioxide gas, or a mixture of these gases is used.} is explained. Reference number 88 is a circuit that puts compressed air (gas, pressurized fluid in a broad sense) into the bottom of the fixed side insert, and pressurizes the inside of the cavities 55, 56 from the gap (not shown) between the fixed side insert (reference number 89) and reference number 104 (fixed side mold plate), and the inventor calls this L3 (pressurized air into the cavity from the fixed side). During filling of the cavity with foamable resin or non-foamable resin, after filling is completed, and after a certain time has passed since filling is completed, the compressed air in the mold is exhausted to the atmosphere through the same circuit. Reference number 66 is an arrow that indicates the flow of compressed air in the mold, and in order to show that the pressurization and exhaustion in the mold are performed through the same circuit, both the beginning (start point) and the end (end point) are illustrated as arrows. Reference number 90 is a circuit that pressurizes the cavity 55 and reference number 56 from PL, and reference number 91 indicates the flow direction of the pressurized fluid (for example, gas). Reference numbers 90 and 91 are called L2 and are pressurized fluid (for example, gas) circuits that pressurize the cavity from PL and exhaust it. Reference number 95 is a compressed air fluid (gas) circuit that pressurizes the inside of the ejector box of reference number 75 by drilling a hole in reference number 74 and exhausts it. Reference number 96 is an arrow (the start point and the end point are also indicated by arrows, as with L3) that indicates the flow of compressed air fluid (gas) in the ejector box. When the inside of the ejector box is compressed, for example, gas (compressed air) in the ejector box pressurizes the inside of the cavity (reference numbers 55 and 56) through the gaps of the ejector pins and the gaps of the insert, and in the present invention, this is called L1. When the ejector box is vented after the molten resin is filled, the pressure inside the ejector box decreases, and as a result, the pressure inside the cavity decreases.

[0095] The ejector box structure has a simple sealing method and a high sealing effect, but the ejector box is larger in volume than the cavity, and a large amount of air is required to pressurize a mold sealed with the ejector box structure. Moreover, it takes time to pressurize the mold, which results in economic problems such as the extra air costs and time required for pressurization, resulting in a longer molding cycle.

[0096] FIG. 20 explains a means for sealing the ejector pin to solve the problem of FIG. 19. The difference between FIG. 19 and FIG. 20 is that the ejector mechanism is enclosed by the "R" shape of reference number 74, but the ejector pin is sealed by the weighted O-ring of reference number 103, so the spacer block of reference number 105 can be of a normal shape. As a result, the O-rings of reference numbers 79 and 81 are not necessary. Reference number 93 pressurizes the cavities 55 and 56 through the gap between the bottom of the movable insert and the ejector pin. Reference number 94 is an arrow indicating the flow of the compressed air and exhaust fluid (gas), and corresponds to L1 in FIG. 19. Reference number 101 is a seal plate into which reference number 103 is fitted and fixed. A groove may be dug directly into the seal plate 101 to insert reference number 103, or the seal plate may be inserted to insert reference number 103. The seal for the inclined pin shown in Figure 24 requires that the weighted O-ring 103 be installed parallel to the axis of the inclined pin, so it is better to use a nested O-ring. Number 102 is an O-ring installed in the gap between the receiving plate 87 and the seal plate 101. The movable side is very different, but the differences between the PL and fixed side seals and the like in Figures 19 and 20 are not great.

[0097] Figure 21 shows the mold structure when processing the undercut shape of reference number 57 shown in Figure 17 with a slide core. Reference number 69 is the O-ring of PL, and reference number 97 is the guide pin or guide post, which is provided outside of reference number 69. Reference number 98 is a fluid (gas) circuit provided in PL to pressurize the insides of reference numbers 55 and 56, reference number 184 is an outlet for blowing out compressed air from the compressed air circuit of reference number 90L2, which is connected to reference number 98 and also to reference number 90 as shown in Figure 22. Reference number 99 is an arrow showing the flow of compressed air and exhaust air of reference number 98. Reference number 68 is the slide core, and reference number 78 is a hole into which the angular pin fits. The slide core of reference number 68 must be placed inside the O-ring of PL of reference number 69 in order to be sealed. The mating surface of the slide (PL surface of the slide) also needs to be sealed (not shown) with an O-ring on the outside of the product shape in the same way as reference number 69. FIG. 21 is a front view of the cavity in FIG. 19 and FIG.

[0098] Figure 22 is a cross-sectional view of the cavity in Figures 19 and 20, where reference number 184 is the L2 circuit, reference number 98 is the L2 fluid (gas) circuit (groove) provided in the PL of the mold, and the inventor has set the cross-sectional shape to, for example, a width (width, width, width) of about 5 mm to 10 mm and a depth of about 1 mm to 3 mm. Reference number 100 is a vent, which is a circuit for pressurizing and exhausting air to 55 and 56 of the cavity, and is provided at regular intervals {pitch interval of 20 mm to 50 mm)} like a comb shape, rather than being provided all around. The width is about 5 mm to 10 mm, and the depth varies depending on the molten resin, but for resins with high fluidity such as PP, it is about 0.03 mm in consideration of the risk of burrs, for ABS it is about 0.05 mm to 0.1 mm, and for modified PPO, PC, etc., which do not have high fluidity, the risk of burrs is low and it is acceptable to have a depth of 0.1 mm or more.

[0099] FIG. 23 shows a means (mold structure) for treating the undercut of reference number 59. In the case of such a shape, an inclined core is used. Reference number 107 is an inclined core. The movable side including the movable side mold plate of reference number 70 moves back, and the PL of reference number 61 is opened. When the ejector rod (not shown) provided in the molding machine is pushed, the ejector plate (ejector plate) composed of reference numbers 77 and 78 is pushed forward, and the ejector pin of reference number 70 and the shaft of reference number 108 are also pushed out as shown by the arrows (reference numbers 109 and 110). As a result, the resin filled in reference number 56 (a molded product that has been cooled and solidified) is pushed out. The inclined core of reference number 107 moves in the direction of the arrow of reference number 111 (perpendicular to the opening and closing direction of the mold in FIG. 23). The molded product moves relative to the inclined core 107 as indicated by reference numeral 112, and the undercut indicated by reference numeral 59 comes out of the mold, allowing the molded product to be removed. In FIG. 23, the load type O-rings 103 and 106 are arranged facing the cavity, but if they are arranged in the opposite direction, a mold structure can be created in which the cavity is made into a vacuum (meaning a reduced pressure below atmospheric pressure) for molding.

[0100] FIG. 24 shows that when there are multiple inclined cores that cross closely with each other, it is difficult for the weighted O-ring to seal adequately with only one seal plate. In such a case, sealing is possible by using multiple seal plates (FIG. 24 shows the use of two plates, reference numbers 101 and 116).

[0101] The outer GCP "pressurizes" or "pressurizes" the inside of the mold (cavity, molding space). "GCP pressurization," "GCP pressurization," and "applying a GCP" are synonymous with using gas to increase the pressure inside the mold before filling it with molten resin. Also, "exhaust." "Exhausting a GCP" is synonymous with venting the gas that has pressurized the inside of the mold into the atmosphere during or after filling with molten resin, lowering the pressure inside the mold and causing foaming. Sometimes a vacuum is used.

[0102] (Hollow molding) When using a pressurized fluid injection pin (Figure 29) consisting of an ejector pin (Figure 27) and an ejector sleeve pin (Figure 28) to perform hollow molding of non-foaming resin, the problem is the speed of exhausting the pressurized fluid from inside the molded product. Since the injection is originally at high pressure and is put into the molten resin in the cavity, the injection pressure is constant and the injection speed is not a big problem. In the case of exhaust, the pressurized fluid in the hollow part must be exhausted to reference number 122 through a narrow gap (about 0.01mm to 0.08mm) as shown in Figures 27, 28, and 29. As the exhaust progresses, the pressure in the hollow part of the molded product decreases, making it difficult to exhaust, and the exhaust speed slows down. If the pressurized fluid in the hollow part is not exhausted sufficiently and completely, when the mold is opened, the residual pressure inside the hollow part causes the molded product to swell and burst. To solve this problem, a mold with an ejector plate (B) consisting of reference numbers 117 and 118 (Figure 25) is used. Before the resin is filled, the ejector plate (B) is advanced by a stepped ejector rod, and non-foaming resin and foaming resin are filled. During the resin filling process and after filling is completed, pressurized fluid is injected from reference number 121, and the inside of the molded product is hollowed out through the pressurized fluid injection pin at reference number 120 (assembled in Figures 27 and 28). After hollowing out, the exhaust valve of the hollow molding device is opened to exhaust the pressurized fluid that was put into the hollow, and once the pressure has dropped, the ejector plate (B) is moved backwards {; this is possible by lowering the ejector rod. Springs, gas springs, etc. are installed in the ejector plate (B), and when the ejector rod is lowered, the force of the springs, etc. forces the ejector plate (B) down.}, the tip of the pressurized fluid injection pin 120 separates from the boss 123 (provided for the purpose of directing the pressurized fluid into the molten resin) that surrounds the tip of the pressurized fluid injection pin of the molded product, creating a space, which is then exhausted all at once. In Figure 25, the ejector pin 67 penetrates the ejector plate (B).

[0103] This is an effective method for foam molding products with high expansion ratios using foamable resins, and for thermoplastic elastomers with low resin rigidity. When molding foam moldings with expansion ratios of 2x, 3x, 5x, or even higher, the cavity is filled with foamable resin that has been given foaming properties using a liquid, gas, or solid foaming agent (either alone or in combination), making the inside hollow. With pressure still applied to the hollow, the mold is returned and the core is returned, venting the pressurized fluid in the hollow, and the pressurized fluid pressurizing pin is retracted {the ejector plate (B) is retracted.} The pressure in the hollow is suddenly reduced, and foaming begins toward the inside. In the case of molded back as shown in Figures 11 and 12, the foaming ratio must be about 2 times or there is a risk of flashing. In the case of core back as shown in Figures 13 and 14, there is no risk of flashing. An outer GCP may also be used.

[0104] (Method of avoiding defects such as swelling and bursting during blow molding) The filling of the cavity with the molten resin starts (the injection start signal is output), and during the filling, or immediately after the filling is completed, or after a predetermined delay time has passed, the injection valve of the blow molding device is opened to start the hollowing of the molten resin. After the predetermined time for opening the injection valve (called the "injection time" in this invention) is completed, the pressurized fluid is trapped in the hollow. This is called the "retention time" in this invention. After the retention time is completed, the exhaust valve of the blow molding device is opened and the pressurized fluid in the hollow is exhausted to the atmosphere. After the time is up on a timer that is started (triggered) by the start of exhaust, the ejector plate (B) is moved backward until no swelling or burst occurs due to the pressurized fluid in the hollow, and after cooling and solidification are completed, the mold is opened and the molded product is removed. The mold in Figure 25 shows a sealed mold of GCP specifications, but in the case of blow molding using non-foaming resin, sealing is not necessary, and there is no need to seal the PL, etc. as shown in Figure 36. Of course, if the mold in Figure 25 is used without using GCP, the function of the mold will be the same as that in Figure 36.

[0105] (Compressed Air Molding) When performing mold backing and core backing, the mold release reproducibility decreases at that stage when separating from the mold. Therefore, pressurize from the inside (hollow molding) and perform mold backing and core backing in a state where it is sufficiently adhered to the mold. Separately, a non-foaming resin or a foamed resin with high mold reproducibility can be obtained by using a means of injecting a pressurized fluid into the gap between the molten resin and the mold and performing mold backing and core backing while applying pressure to the opposite side of the fluid pressurizing surface with the pressure of the pressurized fluid. Note that hollow molding and pressure air molding can be used in combination. In this case, there are cases where the pressure of the pressurized fluid for forming the hollow molding (referred to as "H pressure" in the present invention) and the pressure of the pressurized fluid for performing the pressure air molding (referred to as "P pressure" in the present invention) are such that P pressure > H pressure, P pressure = H pressure, and P pressure < H pressure, and the size of the hollow part formation changes in each case. When using this combination of hollow molding and pressure air molding, it becomes possible to control the size of the hollow part in a PP hollow molded product that was difficult with only hollow molding.

[0106] (Mold structure for pressure air molding) Figure 26 shows the structure of the mold used in compressed air molding. Reference number 125 is a pressurized fluid pressurizing pin (Figure 32), which is made by additional processing of the ejector pin (Figure 30) and the ejector sleeve (Figure 31). The pressurized fluid pressurizing pin is installed between the ejectors because the pressure used is high. It is assumed that the strength of the ejector and the strength of the bolts assembling the ejector plate will not be enough if pressurized fluid is injected, so the inventor installed a plate at reference number 133 on the movable side mounting plate at reference number 80, and fixed with sufficient strength by pressing it down with the die plate (not shown) of the molding machine and the spacer block 105, so that it can withstand the pressure of the pressurized fluid. Reference number 127 is a load type O-ring that seals the gap between reference number 125 and reference number 127. Reference number 128 is a seal plate for installing (fixing) reference number 127, and an O-ring at reference number 102 is installed between reference number 87 and reference number 101 as necessary. Number 126 (also an additionally processed part of the ejector sleeve) is placed in number 129 ejector plate (upper) and number 130 ejector plate (lower). The ejector plate (C) consisting of numbers 129 and 130 moves with the ejector rod as shown by the arrow of number 130. Before the resin is filled, the ejector plate (C) is in the forward position. When the resin is filled into numbers 55 and 56 and the ejector plate (C) is moved backward immediately after filling is completed or after a short delay, number 126 also moves backward, creating a small space in number 135. Pressurized fluid is poured into this space from number 132, and the pressurized fluid reaches number 135 through the gap between the outer tube and core (inner core) of number 125, enters the gap between the resin and the mold, and pressurizes the resin with the pressure of the pressurized fluid. The ejector plate (C) is moved backwards to create a space, disperse the pressure, and fill the resin so that it does not become hollow, as mentioned above. If the resin does not become hollow due to compressed air molding, this mechanism does not need to be provided. Although not shown in the figure, the tip of reference number 135, and if necessary, the surrounding area, can also be embossed on the surface where the compressed air is applied, so that the resin does not become hollow, but enters the gap between the resin and the mold, and the embossing creates a wedge effect. The pressurized fluid equipment used for pressure molding can be the same as that used for blow molding (the same equipment can be used for both blow molding and pressure molding. If this equipment is used to feed pressurized nitrogen gas or carbon dioxide gas (the pressure should be higher than the pressure of the molten resin inside the heater barrel) into the compression zone of the heater barrel instead of into a mold, it is also easy to implement Mucel (product name?) or AMOTEC (product name?), and in this case the program can be written into the molding machine's PLC.).

[0107] (Mold back, core back, outer GCP, inner GCP) In this invention, the GCP in which the inside of the mold is pressurized in advance using the sealed mold shown in Figure 26 is called the outer GCP, and the blow molding using foamable resin is called the inner GCP. When the inner GCP is used, by performing core backing (which is difficult to implement with mold backing due to problems such as burrs and leakage of the pressurized fluid to the outside), it is possible to greatly expand the cavity, and a foam molded product with an even higher expansion ratio can be obtained than with mold backing. When mold-back or core-back is performed using an inner GCP, mold-back or core-back begins at the same time as the pressurized fluid starts to be injected into the molten resin, or after the injection has started and a certain time has elapsed, or when the injection valve is closed and the hollow molding (in this case, the inner GCP) program reaches the hold time, or during the hold time, or when the hold time is completed and the exhaust valve is opened and exhaust begins.

[0108] (GCP) By programming the GCP for the blow molding, mold back, and core back, it is possible to create a smooth foam molded product with a large expansion ratio and a clean surface free of swirl marks. The GCP issues a command to the GCP device that the mold is closed, and pressurizes the inside of the mold (the entire mold including the cavity, in a sealed mold as shown in Figure 25, etc.). In this pressurized state, the cavity is filled with foamable resin that has been given foaming properties. During or immediately after filling is complete, or after filling is complete, the pressure valve of the GCP device is closed and the exhaust valve is opened to release the compressed air inside the mold.

[0109] A separate controller (with a built-in PLC) is set up for the molding programs that operate the blow molding, compressed air molding, mold bag, core bag and GCP devices, and the molding machine receives signals to command the controller and sends them to the controller. It is also common for the controller to output signals to the molding machine and exchange them (meaning that they operate with each other's signals), but the molding machine originally has a PLC (sequencer), so if you write in programs such as blow molding, compressed air molding, GCP, mold bag, core bag and liquid foaming agent, a signal to start metering to the liquid injection device to start injection into the heating barrel, stop liquid injection when the injection time is up or when metering is completed, set the liquid injection position during metering in advance, start liquid injection when the screw passes that position, and stop liquid injection when the screw passes a preset liquid injection stop position, then there is no need to retrieve troublesome signals or use an external controller. It is also possible to write a program to seal the hopper with nitrogen (a means of injecting nitrogen gas into the hopper to prevent discoloration and burning), or to start injecting nitrogen gas into the hopper when measurement starts and stop the nitrogen gas when measurement stops. Nitrogen gas can also be continuously injected into the hopper by changing the switch on the molding machine screen. It is also possible to perform intermittent injection in relation to measurement, such as starting nitrogen sealing when measurement starts and sealing with nitrogen gas when measurement is completed.

[0110] In the molding method using pressurized fluids exemplified by the pressurized gas and pressurized liquid explained in this invention, when controlling a GCP device, a blow molding device, a compressed air molding device, a liquid injector, etc., there are two cases: when each device is operated by writing a program into a PLC (sequencer) in the control panel of the molding machine, and when these devices are operated by writing a program into a PLC in a controller installed separately outside for the purpose of operating these devices, signals are exchanged between the molding machines, and these devices are operated. Each case will be explained in detail below.

[0111] (Injection of liquids and, if necessary, gas) (When writing to the molding machine's PLC) The molding machine software is explained below for injecting gas and / or liquid into the heating barrel to give foaming properties to the molten resin in the plasticization stage. The program written into the molding machine's PLC software first starts metering, and when a certain amount of time has elapsed from 0 seconds (the delay time can be set as desired), the valve (reference number 161) of the externally provided liquid and / or gas injection device (Fig. 35) is opened and the liquid is injected, for example, into the initial location of the compression zone in the heating barrel of the molding machine. The liquid is vaporized by the temperature of the heating barrel and the temperature of the molten resin, and is pressurized and dissolved and finely dispersed in the molten resin in the heating barrel by the back pressure during metering and the pressure applied to the molten resin in the heating barrel. The gas (nitrogen gas, carbon dioxide gas, etc.) is pressurized and dissolved and finely dispersed in the molten resin as it is.

[0112] Injection can be stopped when the screw passes a preset position. Alternatively, the start time for injection can be preset, and the start of injection can be treated as a zero start, and injection can be stopped when the time is up (end). The amount of injection can be constant, but if the screw rotation speed changes, the amount of resin plasticized will naturally change, so the injection amount (plunger pump discharge amount) may be synchronized with the screw rotation speed as necessary.

[0113] (For external controllers) When using an external controller rather than writing a program for injecting gas and / or liquid into the molding machine's PLC, signals are exchanged between the molding machine and the controller. The injection molding machine sends a signal to the external controller that it has started metering. The controller, upon receiving the signal, arbitrarily sets a fixed delay time from 0 seconds, and when the time is up, begins injecting the gas and / or liquid into the heating barrel. When the screw passes a stop position arbitrarily set on the molding machine, it outputs a signal to the controller, and upon receiving that signal, the controller stops injecting the gas and / or liquid. The program is reset by this stop signal.

[0114] In injection control by time control, the controller that receives a signal to start injection has a timer that can be set arbitrarily, sets the arbitrary injection time, and stops the injection when the injection time is up. For synchronization with the screw rotation speed, the screw rotation speed is output as a continuous signal to the controller, and upon receiving this signal, the controller controls the gas and / or liquid injection device to change the injection amount.

[0115] In the case of liquids, which are incompressible substances (volume changes little due to pressure), the injection volume can be easily controlled by changing the speed at which the plunger pump piston is pushed, for example the rotation speed of a rack and pinion motor or servo motor, while in the case of gases, which are compressible substances (volume changes much due to pressure), the injection volume is controlled using an automatically opening and closing needle valve, etc. In some cases, multiple injection machines are used, and the controller is installed with one program for each injection machine so that it can receive signal output and input from the molding machine.

[0116] (Compressed air at GCP) (When writing to the molding machine's PLC) Figure 34 is a schematic diagram showing an overview of GCP measures. Reference number 151 is the air pressure valve, and reference number 154 is the exhaust valve. When writing a GCP program into the molding machine, reference number 151 is opened after an arbitrarily set time has elapsed from 0 seconds upon receiving a mold closing completion signal, and the inside of the sealing mold is pressurized (pre-pressurized) to a pressure equal to or higher than atmospheric pressure. An arbitrarily set timer is used for the time to pressurize the inside of the mold, and after the time is up, the molding machine starts filling the cavity with foamable resin or non-foamable resin. In some cases, the air pressure inside the mold is measured using a pressure sensor, and filling starts when the pre-set pressure is reached.

[0117] (Compressed air at GCP) (For external controllers) When the GCP program is not written in the molding machine's PLC and an external controller is used to control the GCP device shown in Figure 34, the molding machine outputs a mold clamping completion signal to the external controller. Upon receiving this signal, the controller opens the GCP device (reference number 151) and pressurizes the inside of the mold. After the time for pressurizing the inside of the mold, which is preset in the controller, is up, the controller outputs an injection start signal to the molding machine, and upon receiving this signal, the molding machine starts filling the cavity with molten resin. Alternatively, if the controller confirms that a pressure sensor that monitors the compressed air pressure installed in the mold has reached a preset pressure, the controller outputs an injection start signal to the molding machine, and upon receiving this signal, the molding machine starts filling.

[0118] (GCP exhaust) (When writing to the molding machine's PLC) The compressed air in the mold can be exhausted during filling (at any position of the screw), after filling is completed, or after a certain time has passed after filling is completed. In the case of a molding machine, the exhaust valve 154 is opened to exhaust the compressed air in the mold when the screw position is set to the PLC, or after a time set arbitrarily from 0 seconds has passed.

[0119] (GCP exhaust) (For external controllers) When exhausting using an external controller rather than the PLC inside the molding machine, the molding machine outputs an exhaust signal to the controller. For exhausting during filling, an exhaust signal is output to the controller when the screw passes a position that is set arbitrarily, and for exhausting after injection is complete, an injection completion (primary pressure completion or secondary pressure completion) signal is output. Upon receiving this signal, the controller starts an internal timer, and after a set time has elapsed from 0 seconds, the exhaust valve 154 is opened to exhaust air.

[0120] {Mold back, core back} (When writing to the molding machine's PLC) The foaming ratio is increased by retracting the mold (usually the movable mold) a set distance at the start of exhausting compressed air, during exhausting, or after a set time has elapsed from 0 seconds after exhausting is complete. When using the molding machine's PLC, this is performed at the start of exhausting selected, during exhausting, or after a set time has elapsed from 0 seconds after exhausting is complete. When operating with pressure, the mold starts to retract when the pressure gauge installed on the mold reaches a preset pressure (the set exhaust pressure).

[0121] {Mold back, core back (mold recession)} (When using an external controller) When an external controller is used, as soon as exhaust starts, a signal to retract the mold is sent to the molding machine, causing the mold to retract (the mold retracts at the same time as exhaust starts). Or a timer starts when exhaust starts, and when the timer is up, a signal to retract the mold is sent to the molding machine, causing the mold to retract (the mold retracts during exhaust). In some cases, a timer starts when the controller starts exhausting, and when exhaust is sufficiently complete, a signal to retract the mold is sent to the molding machine, causing the mold to retract (the mold retracts after exhaust is complete). It is also possible to have a timer in the molding machine PLC, rather than in the controller. In this case, a signal to start the exhaust timer is output. To monitor the pressure and cause the mold to retract, a signal to retract the mold is sent to the molding machine when the air pressure drops to the set pressure, and the mold is retracted after an arbitrarily set time has elapsed from 0 seconds after receiving that signal.

[0122] The above example shows the case where there is only one GCP device, but if multiple devices are used (L1, L2, L3: L1 = space under the movable insert or space such as the ejector box, L2 = cavity, L3 = space under the fixed insert), prepare the same number of programs for pressurizing and exhausting the air inside the mold, whether in the molding machine's PLC or in the controller. There are also cases where L1, L2, and L3 are exhausted with one GCP device. When pressurizing and exhausting air using a pressure gauge, the main pressure is the cavity pressure, but other pressures are also acceptable. The mold retreat is a means of increasing the volume of the cavity and increasing the foaming ratio.

[0123] (Pressurized fluid injection, retention, and evacuation during blow molding) (When writing to the molding machine's PLC) Hollow molding (including inner GCP) is a molding method in which, using the device shown in Figure 35, gas (such as air, nitrogen gas, carbon dioxide gas, etc.) at atmospheric pressure or higher is injected into the molten resin in the cavity during or after filling of the cavity with foamable or non-foamable resin, for example, using a pressurized fluid injection pin (120), to make the inside hollow, or liquid (such as heated water) pressurized to a high pressure (high pressure) is injected to make the inside hollow. The hollow molding program written into the PLC of the molding machine can be used in two ways: when the screw passes a position arbitrarily set in advance, the pressurized fluid injection valve (161) is opened to inject pressurized fluid (pressurized fluid injection during filling, pressurized fluid injection during filling), or when pressurized fluid is injected immediately after filling is completed or after an arbitrarily set time has elapsed from 0 seconds (pressurized fluid injection after filling is completed). The injection pressure is set using a regulator (165). The injection time is arbitrarily set (called the "injection time"). After the injection time is complete, injection valve 161 closes, and the time for which the pressurized fluid is trapped inside the mold (called the "retention time") is set as desired. After the retention time is complete, exhaust valve 163 is opened and the pressurized fluid inside the hollow is exhausted to the atmosphere. The pressure of the pressurized fluid is rarely fluctuated during blow molding, but in cases where a profile of the pressure of the pressurized fluid to be injected is to be drawn, for example by initially injecting at high pressure, then lowering the pressure of the pressurized fluid to be injected and then raising it again, the pressure of the pressurized fluid to be injected is measured, and this pressure is fed back to the molding machine's PLC, and the injection pressure is controlled using reference number 165, a needle-type regulator (pressure adjustment valve) that is capable of automatic pressure adjustment.

[0124] When the molding machine retracts the ejector plate (B) consisting of the numbers 117 and 118 at the start of the atmospheric release (the timer starts counting) or after a certain time has elapsed from the start of the counting (this time can also be set to any time), the number 120 also retracts, so the pressurized fluid in the hollow part is completely exhausted and no residual pressure remains, and the problem of bulging and bursting is solved even when the mold is opened. Furthermore, number 120 must be at the forward end before the next resin is filled.

[0125] (Pressurized fluid injection, retention, and evacuation during blow molding) (For external controllers) When using an external controller to operate the equipment in Figure 35, a separate controller is provided to control this equipment, and signals are output and input from the molding machine, interfaced with the controller to operate the equipment in Figure 35 and perform blow molding. The timing of pressurized fluid injection is during the resin filling and after the filling is completed. In the case of during the filling, when the screw passes a predetermined position, the molding machine outputs a signal to the controller to command the pressurized fluid injection. The controller receives this signal and opens the injection valve 161 to start injecting the pressurized fluid into the molten resin. The time for injecting the pressurized fluid is set by a timer installed in the controller, and when the time is up, the valve 161 is closed to confine the pressurized fluid inside the hollow. The inventors call this the "retention time". The length of the retention time is set by a timer installed in the PLC in the controller, which can be set at will. After the retention timer is up, the valve 163 is opened and the pressurized fluid inside the hollow is exhausted to the atmosphere. The exhaust time (called the "release time", "exhaust time", etc.) is set by a timer installed in the PLC, making it possible to set the time at will. When the atmospheric release begins (the timer starts counting), or after a certain amount of time has passed since the start of the count (this time can also be set arbitrarily), or when the atmospheric release timer finishes counting, an ejector plate retraction signal is sent to the molding machine, and when the molding machine receives this signal and retracts the ejector plate (B) consisting of numbers 117 and 118, number 120 also retracts, so the pressurized fluid in the hollow part is completely exhausted and no residual pressure remains, and the problem of bulging and bursting is solved even when the mold is opened. Furthermore, number 120 must be at the forward end before the next resin is filled.

[0126] (Compressed Air Molding) (When writing to the molding machine's PLC) In blow molding, pressurized fluid is injected into the resin filled in the cavity. In compressed air molding, the pressure (force) of the pressurized fluid is inserted into the gap between the molten resin filled in the cavity and the mold, improving the transferability to the opposite surface. The equipment used is that shown in Figure 35, and the mold is that shown in Figure 26. The timing for jetting the pressurized fluid is either during filling, after filling is complete, or a short time after filling is complete, just like with blow molding {If multiple pieces of equipment in Figure 35 are used, prepare a program for each piece and set the best pressurization time (timing) for each.} The settings for the subsequent holding time and exhaust time are almost the same as with blow molding.

[0127] In compressed air molding, the cooling and solidification speed slows down when the mold temperature is increased, so the transfer effect of the pressurized fluid is increased. In this case, in order to prevent the pressurized fluid from entering the molten resin (inside) instead of entering the gap between the resin and the mold, resulting in a hollow molding, the ejector plate (C) consisting of the ejector plate (129) and the ejector plate (130) is moved back during the resin filling process and before the pressurized fluid is ejected after the filling process is completed, creating a small space where the pressurized fluid is ejected, and the pressurized fluid is ejected into that space. The ejector plate (C) consisting of the ejector plate (129) and the ejector plate (C) is moved back during the resin filling process and before the pressurized fluid is ejected after the filling process is completed, the pressurized fluid is ejected into that space. The ejection of the ejector plate (C) consists of the ejector plate (129) and the ejector plate (C) consists of the ejector plate (130) is moved back when the cavity is filled with molten resin and a certain amount of time has passed from 0 seconds (the time can be set arbitrarily). This operation is performed by a program written in the PLC in the molding machine.

[0128] (Compressed Air Molding) (For external controllers) When an external controller is used for compressed air molding without writing a program in the PLC of the molding machine, the process is almost the same as that of the blow molding. The retraction of the reference number 126 is performed by sending a retraction signal from the molding machine to the controller, and the timer in the controller retracts the machine after a certain time has elapsed from 0 seconds after starting. After the timer has timed out, the reference number 161 is opened and compressed air molding is started. After the compressed air time has elapsed, the valve 161 closes, trapping and holding the pressurized fluid, and when the holding timer has finished, the exhaust timer starts counting and the exhaust valve of the reference number 163 is opened to release the pressurized fluid into the atmosphere. When the release of the pressurized fluid is completed (time-out for atmospheric release is completed), the controller sends a mold-opening permission signal to the molding machine, and the molding machine receives this signal, and when various conditions such as the completion of the cooling time are met, the mold is opened and the molded product is removed. The molding machine sends a mold-opening signal to the controller and resets the controller program. Note that the reference number 126 must be at the forward end before the next resin is filled.

[0129] (manual) Since a series of operations such as injecting liquid, stopping, opening valve 151, opening valve 154, opening valve 161, and opening valve 163 must be performed manually, a manual switch is provided on the PLC of the molding machine, and, if an external controller is used, on the external controller. When an external controller is installed, signals must be exchanged between the molding machine's PLC and the external controller's PLC, which makes the programs for both complicated. It is simpler and more economical to write programs for these liquids, and gas injection if necessary, GCP, blow molding, compressed air molding, etc., into the molding machine's PLC. Furthermore, when implementing these programs as combined operations, signal exchange becomes complicated, so it is recommended to use the molding machine's PLC rather than an external controller.

[0130] The following will be described using comparative examples, examples, and embodiments. Comparative Example 1

[0131] Linear aromatic PC resin (Teijin Chemical Co., Ltd., Panlite-L1225WP) of natural color (transparent) was dehumidified and dried for 2 hours at 80℃ in advance, and mixed with 0.7wt.% of sodium bicarbonate (NaHCO3), an inorganic chemical foaming agent, which is a white powder because it is a raw powder. The mold shown in Figures 1 and 2 (top plate thickness is 2mm) was used for foam molding without GCP using a 180-ton injection molding machine made by Toyo Machinery and Metal Co., Ltd. The surface temperature of the mold during molding was about 45℃ on both the fixed (cavity) side and the movable (core) side, and the molten resin temperature was 260℃. The screw of the injection molding machine was cut off at the forward end without using pressure retention, and there was a slight short mold (no chipping of the shape (short mold, short shot)).} and subjected to injection molding to obtain a foamed molded product using sodium bicarbonate as a foaming agent. The surface of the foam-molded product obtained had swirl marks because GCP had not been implemented. In order to check its strength, the molded product was placed on the floor and a person weighing 75 kg slowly put his entire weight on it from above. As a result, it was confirmed that the strength of the original PC was completely lost and that it was as brittle as shrimp rice crackers, and foam-molded PC products using sodium bicarbonate as a foaming agent cannot withstand normal use. Sodium bicarbonate as a foaming agent is not suitable for foam-molding PC. Comparative Example 2

[0132] In Comparative Example 2, the sodium bicarbonate foaming agent used in Comparative Example 1 was changed to ADCA (yellow powder in nature) an organic chemical foaming agent. The amount added was 0.35 wt.%, half the 0.7 wt.% of sodium bicarbonate. The mold, injection molding machine, and molding conditions used were otherwise the same. The obtained molded product was loaded and checked for strength in the same way as in Comparative Example 1, but like Comparative Example 1, it had no strength, and PC molded products using ADCA as a foaming agent cannot withstand use like normal PC molded products. ADCA as a foaming agent is not suitable for PC foam molding. Comparative Example 3

[0133] Using the liquid injection device shown in FIG. 1 of PCT / JP2015 / 062611 and the injection port provided in the heating barrel (shown in FIG. 4 and FIG. 5 of PCT / JP2015 / 062611), a certain amount of ethanol (chemical formula is C2H5OH) was continuously injected at the beginning of the compression zone of the screw in the heating barrel with respect to the weight of the molded product (a value measured at one time) from the start of metering to the end of metering, and foamability was imparted to the plasticized molten resin using ethanol (the ethanol vapor was vaporized in the heating barrel and pressure-dissolved and / or finely dispersed in the molten resin melt-kneaded during metering). A foam-molded product was obtained in the same manner as in Comparative Example 1 and Comparative Example 2. A load was applied to check the strength in the same manner as in Comparative Example 1 and Comparative Example 2, but there was no strength as in Comparative Example 1 and Comparative Example 2, and the PC foam-molded product using ethanol as the foaming agent was not usable. Ethanol as a foaming agent is not suitable for PC foam molding. The same can be done using isopropanol (C3H7OH) instead of ethanol, but alcohol is not suitable for use in the production of PC foam molded products.

[0134] Unlike the PC, the ABS foam molded products, m-PPO (PS or HIPS modified, PA modified, PP modified), PP foam molded products, and 6-nylon foam molded products using the ethanol (EtOH) and isopropanol (IPA) mentioned above show almost no deterioration in physical properties. It is presumed that the molecular structure of the PC changes (becomes lower molecular weight) as a result of the attack by the vapor of ethanol and IPA that reaches a supercritical state inside the heating cylinder, causing a deterioration in physical properties. For the same reason, the foam molded products using PET and PBT with ethanol and IPA also show a significant deterioration in physical properties. Comparative Example 4

[0135] In the above Comparative Examples 1, 2, and 3, no GCP was applied (no use was made), and therefore swirl marks were generated on the surface of each foam-molded product. GCP was applied using the nozzles shown in Figs. 20 to 22 of the document PCT / JP2015 / 062611, the seal mold sealed for GCP shown in Figs. 23 and 25, and the GCP device shown in Fig. 24 (the gas used was 1.4 MPa air compressed by a reciprocating type compressor. In the present invention, the seal mold shown in Figs. 20 and 21 and the GCP device shown in Fig. 15 were used). Foam molding was performed, and a foam-molded product was obtained that had a clean, smooth skin layer without swirl marks on the surface and fine foam cells (foam layer) inside. However, the strength was confirmed in the same manner as in Comparative Examples 1, 2, and 3, and the strength was significantly reduced as in Comparative Examples 1, 2, and 3. EXAMPLES

[0136] While searching for a foaming agent for PC resin from the above Comparative Examples 1 to 4, undried PC (linear aromatic PC resin {Teijin Chemicals Co., Ltd., Panlite-L1225WP}) resin pellets (water absorption rate is about 0.1 wt.%) were molded without using the foaming agent sodium bicarbonate in Comparative Example 1. As a result, several voids caused by the moisture in the resin (moisture that had originally been absorbed) were generated in the spool, runner, and molded product. However, the molded product using this undried PC did not experience a decrease in strength. From this, the inventor hypothesized that water could be used for foam molding of PC, and found the possibility and effectiveness of water from the results of preliminary experiments. After intensive research, the inventor confirmed the fact that water is effective for foam molding of PC resins, and broadly ester resins, and completed the present invention.

[0137] In Comparative Example 3, foam molding was performed using 0.5 wt. % water (distilled water, ion-exchanged water, tap water, city water) instead of ethanol. As a result, as shown in Figure 3, the foam cells are large at several mm (millimeters). However, when water is used as the foaming agent, there is no deterioration in physical properties as with ethanol, and no cracks occur even when loaded. The physical properties of the PC foam-molded product are fully maintained, and water is an effective foaming agent for obtaining a foam-molded product that is fully usable as a PC molded product. EXAMPLES

[0138] (foaming nucleating agent) 100 parts by weight of linear aromatic PC resin (Teijin Chemical Co., Ltd., Panlite-L1225WP) was mixed uniformly with 5 parts by weight of aluminum oxide using a tumbler, and the mixture was fed into a vented twin-screw extruder to produce a pellet-shaped resin composition, which was designated as A001, a master batch containing 5 parts by weight of aluminum oxide as a foam nucleating agent.

[0139] Similarly, a foam nucleating agent master batch B001 was prepared containing 5 parts by weight of silver oxide instead of aluminum oxide.

[0140] Similarly, a foam nucleating agent master batch C001 was prepared containing 5 parts by weight of silicon dioxide instead of aluminum oxide.

[0141] Similarly, a foam nucleating agent master batch D001 was prepared containing 5 parts by weight of silicon carbide instead of aluminum oxide. EXAMPLES

[0142] In Example 1, since no foam nucleating agent was used, the foam cells were large and coarse, but in Example 2, the action and effect of each of the foam nucleating agents aluminum oxide, silver oxide, silicon dioxide, and silicon carbide was confirmed to determine whether the foam cells could be made finer. Panlite-L1225WP was mixed with 5 parts of foam nucleating agents, Masterbatch A001, Masterbatch B001, Masterbatch C001, and Masterbatch D001 (mixing ratio = 100:5), and water (distilled water was used) was injected into the heating cylinder at a volume of 0.4 vol.% of the resin volume under the same conditions as in Comparative Example 1, to obtain a PC foam-molded product using water as a foaming agent. The injection foam-molded product obtained in this Example 3 had a foam structure with fine foam cells due to the action and effect of the foam nucleating agents, A001, B001, C001, and D001, respectively. From the results of Example 3, the foam nucleating agents contained in Masterbatch A001, Masterbatch B001, Masterbatch C001, and Masterbatch D001 in PC, which are substances that refine the foam cells in foam molding, have sufficiently refined the foam cells. The foam moldings obtained containing the foam nucleating agents aluminum oxide, silver oxide, silicon dioxide, and silicon carbide were loaded in the same manner as in Comparative Example 1 to check their strength, and it was found that the inclusion of the foam nucleating agents aluminum oxide, silver oxide, silicon dioxide, and silicon carbide caused almost no deterioration in the physical properties of PC. Of course, the influence of the foaming agent water on the deterioration of physical properties was hardly observed. EXAMPLES

[0143] When the GCP described in Comparative Example 4 was applied to Example 3, a foam-molded product was obtained that had a clean and smooth skin layer without swirl marks on the surface and foam cells of about 50 μm or less inside. EXAMPLES

[0144] In the above-mentioned Examples 3 and 4, the foam nucleating agents Masterbatch A001, Masterbatch B001, Masterbatch C001, and Masterbatch D001 were used separately and alone, but the amount of foam nucleating agent was mixed and used by mixing two or more kinds of master batches, such as 5, A001 2.5 and B001 2.5, or A001 2.5 and C001 2.5, as in the examples. In the case of three types of foam nucleating agents, A001, B001, and C001, the mixing ratio was 5, or when all of A001, B001, C001, and D001 were used, the action and effect of each foam nucleating agent was fully exerted, and it was confirmed that the foam cells were finer. Naturally, the more the amount of foam nucleating agent added, the finer the foam cells, and the less the amount added, the coarser the foam cells. Because it is a master batch, the desired foam cell size can be achieved by controlling the amount added, whether it is large or small. When implementing GCP, the optimum amount can be found by checking whether or not swirl marks occur on the surface (adding more foam nucleating agent makes the foam cells finer, but the foaming power increases and swirl marks occur on the surface. In this case, by increasing the GCP pressure or using carbon dioxide gas in the GCP, a clean, smooth foam molding can be produced with a surface free of swirl marks). EXAMPLES

[0145] Can the present foam nucleating agents, aluminum oxide, silver oxide, silicon dioxide, and silicon carbide, refine the foam cells not only with PC alone but also with PC-based resins? As a result of confirming the usefulness of using water as a foaming agent, the methods of Examples 2 to 4 were carried out in the same manner for all of the molding materials shown below, and the results showed that it was effective. The resins used were PC / ABS, PC / PS (polystyrene), PC / PVC (vinyl chloride, polyvinyl chloride), PC / polyamide (PA), etc. When using water as a foaming agent with PC-based resins, distilled water is preferable, but ion-exchanged water is also acceptable. City water or well water can be used, but calcium ions (Ca 2+ ), magnesium ion (Mg 2+The presence of ), accelerates the decomposition of PC, so it is preferable for the total hardness (total concentration of calcium ions and magnesium ions) to be 100 ppm or less (water), and even better to have it at 35 ppm. Although foam nucleating agents also have an effect on PC / PET, PC / PBT, and PC / PEN (polyethylene naphthalate), as mentioned above, these resins hydrolyze in the case of PET, PBT, and PEN, resulting in a significant decrease in physical properties. These foam nucleating agents are not limited to PC resins, but can also be used as foam nucleating agents for styrene resins such as ABS and HIPS, olefin resins such as PP, nylon resins, and vinyl resins such as PVC. EXAMPLES

[0146] During plasticization and weighing of Sumika Polycarbonate Co., Ltd.'s PC {SD Polyca (product name) 301-15 (grade)}, 0.5 wt.% of ion-exchanged water was injected from the start of weighing to the end of weighing, relative to the weight of the molded product (weight of the molten resin in the heating barrel) shown in Figures 1 and 2, and vaporized in the heating barrel, imparting foamability to the heated and melted PC resin, resulting in the molded product shown in Figure 3. Since no foam nucleating agent was mixed into the molded product obtained, the foam cells were coarse and large, about 2 mm to 5 mm, but there was no deterioration in physical properties as with baking soda, ADCA, or ethanol, and the original physical properties of PC were displayed (Figure 3).

[0147] Immediately after the GCP was evacuated, the movable mold was moved back 1 mm, and the mold back was performed 1 mm from the plate thickness of 2 mm immediately after the GCP was evacuated, increasing the foaming ratio. The pressure applied to the molded product by the resin was reduced by the mold back, and as a result, the foam cells grew to 10 mm, and in some places reached 20 mm (Fig. 4). Despite the molded product having such large foam cells, the inside of the mold was pressurized to 1 MPa using the GCP device shown in Fig. 15, and water was used under pressure to impart foaming properties to the above-mentioned PC resin molded product. The surface was clean and smooth, with no swirl marks at all (Fig. 4). Furthermore, the surface of the molded product, such as that shown in Figure 4, is textured to prevent the raindrop phenomenon, a problem specific to GCP.

[0148] GCP was performed with air at a pressure of 1 MPa, and a foamed molded product with a clean and smooth surface was obtained. However, since no foam nucleating agent was added, the foam cells were very large (size (diameter) was about 5 mm, and in some places was more than 5 mm) (Fig. 3, Fig. 4). EXAMPLES

[0149] When Sumika Polycarbonate Co., Ltd.'s PC {SD Polyca (product name) SI8000L (grade)} was foamed with ion-exchanged water in the same way, ultra-fine foam cells were obtained. When GCP was performed with the same air at a pressure of 1 MPa, the foaming power was too strong and it was not possible to push the swirl marks on the surface. In the above Example 7, only 301-15 was used, so the foam cells were coarse and large, but by using (mixing) SI8000L, the foam cells were refined, and it was confirmed that the swirl marks on the surface could be somewhat suppressed by GCP. 70 parts of 301-15 pellets were mixed with 30 parts of SI8000L pellets, and the components in SI8000L were used as a foam nucleating agent. Compared to Figures 3 and 4, the foam cells were refined, and it was visually confirmed that foam cells of 1 mm or less were uniformly distributed inside the molded product (Figure 5). The foam nucleating agent used in this example was a light diffusing agent. EXAMPLES

[0150] A mixed resin of 80 parts of 301-15 pellets and 20 parts of SI8000L pellets was foamed in the same manner using ion-exchanged water. GCP was performed in the same manner as in Examples 7 and 8, and although the number of swirl marks on the surface was further reduced compared to Example 8, a clean, smooth foamed product without swirl marks could not be obtained. EXAMPLES

[0151] Example 10 is a case where the mixing ratio of Example 9 is changed, and the mixing ratio is 90 parts of 301-15 and 10 parts of SI8000L. As a result, the swirl marks on the surface disappeared with GCP using 1 MPa air (the gas used was compressed by a compressor at a pressure of about 1 to 1.2 MPa), and a PC foam-molded product with a clean, smooth surface and fine and clean foam cells was obtained. It was confirmed that the strength of the foam-molded product obtained was sufficient. Figure 5 (photo) shows that in this Example 8, the core side was retreated by 0.5 mm after exhausting the GCP, increasing the foaming ratio {(2 mm + 0.5 mm (mold retreat amount = mold opening distance) ÷ 2 mm (initial plate thickness) = 1.25 (volume expansion of 25 vol.%). The diameter of the foam cells is about 1 mm and exists throughout the molded product. Due to the action and effect of the GCP, the surface of the molded product is clean and smooth without any swirl marks. EXAMPLES

[0152] A polymer alloy of PC and ABS manufactured by Sumika Polycarbonate Co., Ltd. {SD Polyca (product name) IM6011 (grade)} was foam-molded using ion-exchanged water in the same manner as in Example 7. The GCP was air and the pressure was 1 MPa. The PC / ABS ("PC / ABS" means a polymer alloy of PC and ABS) used in this Example 11 was black in color, and the pigment acted as a foam nucleating agent, resulting in a fine foam layer inside and a clean, smooth foam-molded product with no swirl marks on the surface. When ethanol was used as a comparative example, the physical properties were decreased. From this, it is concluded that water is also an effective blowing agent for PC-based polymer alloys. EXAMPLES

[0153] In this Example 12, the resin used in Example 11 was confirmed to be that of another company. Instead of IM6011, PC / ABS {Techniace (product name) T-251T-15 (grade)} from Nippon A&L Co., Ltd. was used. The obtained foam molded product had a smooth surface and fine foam cells inside, similar to Example 11. When ethanol was used as a comparative example, the physical properties were reduced. From this, it is judged that water is also effective as a foaming agent for PC-based polymer alloys. EXAMPLES

[0154] A polymer alloy of PC and PET (polyethylene terephthalate) {SD Polyca (product name) IM401-18 (grade)} manufactured by Sumika Polycarbonate Co., Ltd. was used and foamed with ion-exchanged water in the same manner as in Example 7, but the physical properties of PC / PET were not observed at all, and it was assumed that this was due to hydrolysis of PET. PET is used for cosmetic containers. When this cosmetic PET resin is foamed with alcohol, no deterioration in physical properties is observed. EXAMPLES

[0155] The inclined pins shown in Figures 23 and 24 were sealed with a load type O-ring, and the load type O-ring 106 was fixed with a nest 113 in a sealing mold. After confirming that there were no leaks, air was used as the gas and a pressure of 1.4 MPa was applied in the GCP device shown in Figure 15, and this sealing mold was used for foam molding using PP as the molding resin and a liquid mixture of ethanol and tap water in a 4:6 ratio as the foaming agent, and a smooth foam molded product with a clean surface without swirl marks was obtained. Generally, the GCP is air using a reciprocating or screw type compressor, but nitrogen gas is used if discoloration or burning occurs with air. If carbon dioxide gas is used, the carbon dioxide gas will enter the tip of the molten resin filled in the cavity and improve the fluidity. The gas used in the GCP is not limited to one type, but can be a composite gas such as air and nitrogen gas, air and carbon dioxide gas, or air, nitrogen gas and carbon dioxide gas. The pressure of the GCP varies depending on the foaming agent that gives the molten resin foamability, the type and amount of foaming gas, the resin that gives foamability, and the temperature of the resin. The GCP is a useful means to suppress foaming and eliminate swirl marks, but the gas in the mold is a troublesome and hindrance (object, person) when filling the resin, so if it is possible to suppress swirl marks, it is better to have a low pressure GCP that is an obstacle. The pressure of the GCP of the present invention is a high pressure, i.e., it is sufficient if it is greater than atmospheric pressure to suppress swirl marks. In the case of general foam molding, the GCP pressure is preferably in the range of 0.5 MPa to 2.5 MPa. If it is less than 0.5 MPa, it is not possible to suppress swirl marks and obtain a clean, smooth surface. If it is 2.5 MPa, the foam cells will be crushed by the GCP pressure (pressure of compressed air), and a foam layer will not be formed inside, so it is not preferable. In the case of foam molding, the GCP pressure should be about 0.5 MPa to 2.5 MPa. If the goal is to eliminate silver during general molding using non-dried materials, a pressure of 0.5 MPa may be possible.

[0156] When increasing fluidity by injecting liquid without foaming, the resin is held under pressure from the injection molding machine to crush the foam cells and prevent foaming (a foam layer is not formed), so the GCP pressure is sufficient as long as there are no swirl marks on the surface of the molded product. There are no restrictions on the GCP pressure as long as there are no short molds, discoloration, or burns caused by filling with molten resin. If necessary, a high pressure of 2.5 MPa or more is acceptable, and in some cases a pressure of 0.5 MPa or less is also acceptable.

[0157] ABS absorbs moisture (water) at about 0.4wt.% and 0.6wt.%. PP containing talc also absorbs moisture at about 0.2wt.% to 0.8wt.%, so drying is required before molding as a measure against silver (silver streaks). However, if a sealed mold is used and a GCP (pressurizing the mold in advance) of about 1MPa is applied inside the mold, it is possible to obtain molded products with a beautiful surface without silver even with the ABS or PP containing talc without drying. By using a GCP, there is no need to dry the ABS as a measure against silver, and there is an economic effect of saving electricity (saving electricity, saving electric energy, saving energy). There is no need to increase the pressure of the GCP more than necessary if silver does not occur. The silver prevention measures for the above-mentioned materials that do not require drying are not limited to ABS, and other materials can be used as well. EXAMPLES

[0158] The inclined pin shown in Figures 23 and 24 was sealed with a load type O-ring, and the load type O-ring 106 was fixed with a die insert 113, and the seal mold was subjected to pressure molding at a pressure of 30 MPa using the blow molding and pressure molding device shown in Figure 35. There was no leakage of pressurized fluid from the shaft (reference number 108) of the inclined core, and it was confirmed that the action and effect of fluid pressurization was sufficient. The molding materials used were PP and ABS. EXAMPLES

[0159] In the mold shown in Figure 25, the resin was PP, and the foaming agent was a mixed solution of water and ethanol 4:6 shown in Example 14. The GCP (to be precise, outer GCP) of Example 14 was performed, and the surface of the foamed molded product was clean and smooth with no swirl marks on the surface. Inner GCP (hollow molding using foamable resin) was performed from the inside at a pressure of 30 MPa. When the internal pressure was sufficient, the pin 120 was retracted, the pressure inside the hollow part was suddenly reduced, and foaming was performed toward the inside. After cooling and solidification were completed, the mold was opened, but no swelling or bursting was observed. The effectiveness of retracting the pin 120 was confirmed even in the inner GCP using foamable resin according to this Example 16. EXAMPLES

[0160] Using the mold shown in Fig. 36, blow molding was performed with the HIPS injection device shown in Fig. 35. In order to eliminate the residual pressure in the hollow, the pin 120 was retracted, the pressure inside the hollow was suddenly reduced, and the mold was then opened, but no swelling or bursting due to the residual pressure in the hollow was observed. This Example 17 confirmed the effectiveness of retracting the pin 120 even in blow molding using a non-foaming resin. EXAMPLES

[0161] The inclined cores (reference numbers 10.7, 108, etc.) shown in Fig. 23 were inserted into the mold shown in Fig. 20, with the load-type O-ring 106 held down by a nest as shown by reference number 113 in Fig. 23. Using this mold, the above-mentioned Examples 1 to 15 were carried out, and it was confirmed that the sealing of the inclined cores was also possible as shown in Fig. 23. Furthermore, using the mold of Example 18, pressure molding was carried out at a nitrogen gas pressure of 30 MPa, and it was confirmed that the mold using the nesting structure to seal the inclined cores was sufficiently pressure-resistant to pressure molding, and had sufficient sealing properties. EXAMPLES

[0162] Example 18 is a mold in which the inclined pins in FIG. 23 are sealed, whereas Example 19 is a sealed mold in which multiple inclined cores and ejector pins are sealed with a load-type O-ring 106 and fixed with a nest 113 as shown in FIG. 24. It has been confirmed that this sealed mold is fully capable of mass production by foam molding using the GCP in Example 18 and compressed air molding. EXAMPLES

[0163] Figure 7 shows an IC tray mold with six pin gates of about φ4 mm on the product surface (reference number 4 is the IC tray cavity). In this case, instead of opening the PL first, reference number 8 was opened and the pin gates were cut, and then the PL was opened and molded back to increase the expansion ratio. ABS and modified PPO (PP modified with PPO) were used for the resin, and foam molding was performed to obtain a foam molded product with a weight reduction of about 30% (about 10% of the amount not using pressure holding, as this is foam molding, and about 20% of the mold expansion due to mold back). It was also confirmed that a GCP of 1.2 MPa was used with air to obtain a foam molded product with a clean surface and a smooth surface without swirl marks. Since IC trays require high dimensional accuracy and little warpage, foam molding and blow molding, which do not use dwell pressure and are molded at low dwell pressure, are good. Foam molding uses a foaming agent, which can be liquid, gas, or solid. Considering the risk of foaming residue in the foam-molded IC tray affecting the IC, gases such as nitrogen gas and carbon dioxide gas, which do not leave foaming residue, or alcohols such as ethanol and IPA, and water are good. Foam molding and blow molding also require less than half the clamping force compared to conventional solid molding, so in addition to stack molding, multiple molded products with the shape of the molded product processed on the same PL surface, and multiple molded products of different types can also be implemented. In fact, the IC tray in Figure 7 (Figure 10 is the IC tray processed in Figure 7) is 135 mm long, 315 mm wide, and 8 mm thick, and in normal molding it is processed using an injection molding machine with a clamping force of 180 tons, with a single mold. However, in foam molding, the required clamping force is at most 80 tons, so a two-cavity process was used in which two of the same IC trays are processed into one mold, or a two-cavity process was used in which two IC trays of different shapes are processed into one mold, and an IC tray with satisfactory quality and little warping or deformation was obtained. EXAMPLES

[0164] A gas injection pin was attached to the fixed side of the runner in Figure 7, and the nitrogen gas was increased to 20 MPa. After filling the cavity with non-foaming resin, gas was immediately injected for 5 seconds to form a hollow section. The gas was then trapped (retained) in the hollow section for 10 seconds, vented, and a hollow molded product with a hollow ratio of 8% (compared to the weight of general molding) was obtained. EXAMPLES

[0165] In the above-mentioned Example 22, a hollow was formed after filling the cavity with a non-foamable resin, but in this Example 22, the mold was retreated by 0.2 mm (mold back) while injecting high pressure gas, resulting in a hollow ratio of nearly 20%. Note that the same experiment was carried out with a foamable resin that had been given foamability using ethanol in Examples 21 and 22, verifying that hollow molding is possible even when a foamable resin is used. EXAMPLES

[0166] Mats that are attached to the floor of an automobile are made of rubber and thermoplastic elastomer (TPE), and in this Example 22, foam molding was performed using elastomer. The foaming agents used were Advancel (trade name) and Expancel (trade name) with medium air bubbles, a master batch with 20 wt.% ADCA supported on the surface of an olefin-based elastomer (TPV), a master batch with 20 wt.% sodium bicarbonate supported on the surface of an olefin-based elastomer (TPV), and ethanol as a liquid foaming agent. It was confirmed that it was possible to foam an olefin-based elastomer using any of the foaming agents. Similarly, foaming was possible with TPS and TPU. It was confirmed that the physical properties of ester-based TPC decreased with both solid and liquid foaming agents, and only nitrogen gas was used for foaming of TPC. TPE is broadly divided into seven categories, including the above-mentioned TPV, TPA, TPC, TPO, TPS, TPU, TPV, and TPZ, and is further divided into 32 categories based on the difference between the hard segment and the soft segment. This Example 22 was explained using an automobile mat as an example, but it is presumed that foam molding is possible for all molded products using TPE. Of course, foam molding alone will cause swirl marks on the surface, so we performed GCP with TPV and TPS using air at a pressure of 1MPa, and obtained a foam structure with no swirl marks on the outside and fine foam cells inside. If the GCP traps air and causes raindrops, open the mold by about 0.1mm to 0.2mm after exhausting the GCP to smoothly exhaust the compressed air in the gap between the resin and the mold. Furthermore, if the inside of the mold is vacuumed after exhausting, raindrops can be reduced even further.

[0167] Using an 850-ton injection molding machine manufactured by Toyo Machinery & Metals Co., Ltd., foam molding was performed using an olefin-based thermoplastic elastomer (hereinafter referred to as material "A"). The foaming agents used were sodium bicarbonate and ADCA. First, the results of foam molding using sodium bicarbonate are explained. A foaming agent master batch was produced by supporting 20 wt.% of sodium bicarbonate on the pellet surface of material A. Material A was blended so that the content of sodium bicarbonate alone in material A was 0.5 wt.%, and foam molding was performed at the melting temperature of material A, 215°C. The obtained foam molded product had no swirl marks on the surface and a foam layer was confirmed inside, but the foaming power of sodium bicarbonate was insufficient and sink marks were generated. ADCA was used instead of sodium bicarbonate, and the ADCA content was 0.25 wt.%, half that of sodium bicarbonate, and a smooth foam molded product with a clean surface without swirl marks was obtained even without GCP, just like in the case of sodium bicarbonate. The foam cells inside were a mixture of fine and coarse (large) ones. We judged that the large foam cells were due to a lack of foaming agent, and increased the ADCA to 0.5wt.%, resulting in fewer coarse foam cells, but no swirl marks on the surface. The initial thickness of the molded product was 3mm, and after filling was completed, the mold was molded back 0.2mm to increase the foaming ratio. Next, a hole was made in the place where liquid can be injected into the heating barrel of the molding machine {close to the compression zone of the screw; in foam molding using liquid, if alcohol or other substances are put into the heating barrel, it will vaporize all at once. It is better to have the molten resin wrapped around the screw and seal it so that the vaporized steam does not leak into the hopper. A liquid injection port is provided in front of the place where the molten resin is wrapped around the screw (towards the nozzle).}, and ethanol is poured in from there, and the vaporized, plasticized, and weighed material A is given foaming properties, and foam molding is performed. As a result, unlike the above cases of baking soda and ADCA, swirl marks are generated on the surface. The difference in the occurrence of swirl marks is that in the case of chemical foaming agents, when the foaming agent master batch is mixed with material A and fed into the heating cylinder from the hopper, some of the foaming agent immediately decomposes thermally and generates foaming gas. Most of the foaming gas generated in thermoplastic resins such as PP and ABS is finely dispersed and dissolved in the resin, and only a small amount escapes to the hopper side, so the foaming resin filled in the cavity has sufficient foaming power, and many swirl marks occur on the surface.On the other hand, with material A, the resin plasticized and melted at a slow rate, and in the case of the chemical foaming agents sodium bicarbonate and ADCA, the decomposition rate of the chemical foaming agent was faster than the plasticization rate of material A, and most of the foaming gas escaped into the hopper, so the desired foaming power could not be imparted to material A, and so foaming was not very strong (there was less foaming gas and in smaller quantities. The foaming power was weak), and so the occurrence of swirl marks was hardly observed. On the other hand, with alcohol, the foaming agent ethanol was added to the resin near the compression zone (to the molten resin) after melting was completed, so many swirl marks occurred. The above material A was mixed with 5 wt.% calcium carbonate as a foam nucleating agent.

[0168] Since the foaming agent used in material A is supported on the surface of the pellets of material A, it is better to use a foaming agent that has been melted and kneaded to contain the foaming agent inside. It is better to plug the heating cylinder after feeding the material containing the foaming agent master batch from the hopper into the heating cylinder so that the foaming gas does not escape to the hopper side. Example 23 was explained using an automobile mat, but the embodiment can be applied to all foam-molded products molded with TPE, not just mats.

[0169] In practice, a mold for an automobile floor mat was used, the TPE to be foamed was TPV, the foaming agent was a solution of maleic acid-modified PP for the TPV, and the foaming agent master batch was used in which the TPV surface was supported with 20 wt.% sodium bicarbonate. The surface of the TPV was used as the carrier resin. As a result of molding, fine foam cells were confirmed in about 60% of the area starting from the gate, but foaming was not possible at the flow end (the end of the molded product). No foam cells were confirmed. This is the result of the foaming gas (carbon dioxide gas, water vapor) generated by sodium bicarbonate escaping from the hopper. It is recommended to provide a check valve at the rear of the screw as shown in reference number 239 in Figure 53 and seal it so that the foaming gas does not escape from the hopper. An injection molding machine with reference number 239 (a molding machine with a screw for the Mucell specification in this example) was actually used.

[0170] In the case of TPE such as TPV, in addition to using the blowing agent master batch mentioned above, if the pellets of TPE to be foamed are supported with, for example, maleic acid-modified PP, the dispersion of the foaming gas improves and uniform foam cells are formed even at the edge of the molded product. Of course, you can use ADCA, or a liquid such as alcohol, or use it in combination with the blowing agent master batch mentioned above, and you can use a screw with the number 239.

[0171] In the case of TPV foam molding, a GCP with a pressure of about 1MPa is used to obtain a smooth TPV foam molding product with a clean surface without swirl marks. Whether using a solid foaming agent such as baking soda or ADCA, or a liquid foaming agent such as water or alcohol, a screw with number 239 makes it difficult for the foaming gas to escape from the hopper. In the case of extrusion molding, a screw with a structure equivalent to 239 can also be used. With a screw that does not have number 239, the vaporized gas from moisture in the resin and residual monomers escapes from the hopper, but with number 239, it is difficult to escape, and silver is generated. In this case, the screw should be replaced or GCP should be implemented. EXAMPLES

[0172] In Example 23, a master batch of a foaming agent in which ADCA or sodium bicarbonate was supported on the surface of material A to be foamed was used. In this Example 24, a master batch was not used, and pellets of material A containing 0.25 wt. of ADCA were produced in advance in the granulation (pelletization) process (stage) of material A. The ADCA-containing pellets were used in the injection molding machine and mold used in Example 23. As a result, a foam-molded product of material A with an even higher expansion ratio than that of Example 23 was obtained.

[0173] A similar experiment was carried out using 0.5 wt. % sodium bicarbonate instead of ADCA, and it was confirmed that the expansion ratio was also higher than in Example 23. The reason why the expansion ratio is higher than that of the method of Example 23 is that when the TPE of material A is melted, for example, ABS, PP, etc., the viscosity drops quickly when melted, and the foaming gases such as nitrogen gas, carbon dioxide gas, and water vapor can be included in the resin (finely dispersed in the molten resin, dissolved under pressure, etc.), but in the case of material A, the viscosity does not drop so quickly even when melted, so most of the foaming gas generated by the thermal decomposition of the foaming agents such as ADCA and baking soda escapes from the hopper. In Example 24, the necessary amount of foaming agents such as ADCA and baking soda are kneaded into material A, so that when material A melts, heat is applied to the foaming agent for the first time and it starts to decompose thermally, making it easier to include a lot of foaming gas in material A, and as a result, sufficient foaming can be achieved even with a small amount of foaming agent. In this Example 24, ADCA and baking soda are shown, but it is also possible to carry out the method with DPT, other hydrogen carbonates (Li, Na, K, Rb, Ca, Mg, etc.) and air spheres. Of course, in this case, if a GCP is used, swirl marks can be suppressed. Naturally, in order to further improve the kneading ability, it is possible to use dulmage or to design the flights so that they have high kneading ability. EXAMPLES

[0174] (Confirmation of improved liquidity.) The inventors confirmed that injecting 1.5 vol.% of ethanol into PP nearly doubles its fluidity. Using a 1,300-ton injection molding machine, when 1.5 vol.% of ethanol was injected into an actual 3D mass production mold (the housing of the office automation equipment used in the 55th embodiment), the PP resin Novatec BC03B {MFR (MI value) = 30g / 10min} showed approximately the same fluidity as the same PP BC06C (MFR = 60g / 10min). This result confirmed that the fluidity of the styrene-based resin ABS was also greatly improved using the same mold. EXAMPLES

[0175] When PP containing 60% by weight of talc was foamed using 1.5% ethanol, the talc was able to sink into the molded product at a pressure of about 1 MPa, and no floating of the talc was observed on the surface of the foamed product. When alcohol was used in this molding experiment, the position at which it was switched to VP changed significantly, and it was confirmed that the action and effect of improving fluidity with ethanol was significant. When resin with increased fluidity using ethanol was filled into the cavity instead of foam molding, and sufficient resin holding pressure was applied from the molding machine screw, the action and effect of improved fluidity was confirmed, but swirl marks {not the foam stripes of foam molding, but silver streaks caused by ethanol} appeared on the surface. Furthermore, floating of the talc added to the resin was also confirmed. It is also possible to sink the talc with IPA.

[0176] At this time, GCP was carried out using air at a pressure of 1 MPa, and as a result, a foam-molded product was obtained with a clean, smooth surface that was free of silver and talc lifting. Even when sufficient holding pressure is applied from the screw to crush the internal cells and produce a general molded product, the fluidity is higher than in the case of foam molding (this is natural since holding pressure from the screw is used), and by using GCP, a smooth general molded product can be obtained with a clean surface that is free of silver and talc lifting. Furthermore, if a solid foaming agent, such as ADCA or bicarbonate, is used, the fluidity improves slightly, but not as much as with liquids. It has been confirmed that the fluidity improves when gases such as MU-CEL and SOFIT are used, but even in this case, it is not as good as with liquids. In the case of Amotech, carbon dioxide gas is used, so a certain degree of improvement in fluidity can be expected, but not as good as with liquids. Handling carbon dioxide gas requires complex and expensive equipment, and equipment using liquids is superior in terms of both initial and running costs.

[0177] The screws that can be used in this invention can be any screw that is capable of general molding, but it can also be a screw with a dulmage like the MUUSEL, a screw with two compression zones like the Soffit screw, or a long screw with an L / D of 28 or 26. In foam molding using gas such as the MUUSEL, a check valve is provided at the rear of the screw to prevent the gas from escaping to the hopper side. Since the liquid is injected into the molten resin, the molten resin behind the part where the liquid is injected acts as a check valve. In the case of a screw with a check valve, the liquid vapor does not escape to the hopper side, so it is possible to pour the liquid into semi-molten resin.

[0178] In the case of foam molding, the process of filling the cavity with molten resin is completed by pushing (stopping) the screw all the way to the forward end. It is also possible to stop midway without stopping. In the case of a hydraulic machine, the process was stopped to stabilize the weight of the filling, but with an electric motor, it is also possible to stop midway without stopping. Also, after filling the foamable resin, the screw is retreated, or / and a dummy shape [see the figures in Patent Documents 1 to 7, and the book "Preparation for mass production of foam molding, blow molding, and compressed air molding, and explanation of specific means for reducing environmental impact" by Yasutoshi Suzuki and Minoru Shinbo, published by S&T Publishing Co., Ltd. on October 20, 2022.] is given and filled with a short mold, etc., to reduce the pressure of the molten resin in the cavity and make it easier to foam. In other words, in the case of foam molding, it is necessary to devise a way to reduce the pressure of the foamable resin filled in the cavity as quickly as possible. To facilitate foaming, the resin temperature and mold temperature should be set higher, as this will slow down the cooling and solidification rate inside the mold, making foaming easier. If the resin temperature and mold temperature are set higher, the surface skin layer will be thinner when GCP is used.

[0179] On the other hand, we will explain the method of using a liquid to increase fluidity and perform general molding. As mentioned above, the substance that increases fluidity is a substance that is liquid at 1 atmosphere (atm) and 23°C, and since it is not intended for foaming, it is a liquid that does not need to vaporize in the heating cylinder or not. In other words, unlike in the case of foaming molding, there is no need to take the boiling point into consideration. From the viewpoint of usability, if you want to improve the fluidity, it is better to vaporize it and dissolve it in the molten resin under pressure (by the back pressure during metering) or finely disperse it. In this way, the molten resin is filled into the cavity with foaming properties, and a cushion amount is given. The resin is held under pressure from the screw in the same way as in general molding, or part or all of the mold is compressed to increase the density of the resin, so that the foam cells are crushed by the pressure, and the foaming gas for the purpose of forming the foam cells is squeezed out of the molten resin by pressure such as these resin holding pressures. Since foam cells are not formed, the GCP pressure can be high. It does not matter if the foam cells are crushed by the GCP pressure. Here, the purpose of the GPC is to eliminate swirl marks and to sink additives, so there is no need to balance the pressure to not interfere with the formation of internal foam cells as in foam molding. Since the fluidity differs depending on the resin, the amount and type of liquid to be injected will differ. There is no need to increase the pressure of the GCP more than necessary, and the lower the pressure, the less likely it is to cause a hindrance to the filling of the molten resin, which can cause short molds, discoloration, and burning. Naturally, if the fluidity is increased by the liquid, the filling pressure can be reduced, and large molded products can be molded at low pressure, so a small molding machine can be used, which is economical. Lowering the filling pressure also reduces the residual stress inside the molded product, resulting in molded products with less warping and deformation. In the case of resins with high fluidity, the transferability to the mold is improved. In the case of crystalline resins such as olefin-based resins such as PP, the cooling and solidification speed at the stage of contacting the mold surface is faster than non-crystalline ABS, HIPA, etc., so the GCP pressure can be set lower.

[0180] It has been confirmed that if carbon dioxide gas is used in the GCP, the gas dissolves from the tip of the flow, further improving fluidity. Amotech has reported that using carbon dioxide gas as a foaming agent increases fluidity, but it does not have the same effect as liquid. Carbon dioxide gas and liquid can also be used together. Since medium air foams such as Advancel use organic solvents, it has been confirmed through experiments that the fluidity is higher than that of baking soda, ADCA, etc. Commercially available medium air foam master batches of foaming agents are manufactured using an extruder, but they can also be supported on PP, ABS, etc. using maleic acid modified PP varnish (solution) or styrene modified acrylic resin varnish (solution).

[0181] In order to improve the fluidity, it is a good idea to apply texture to the non-decorative surface as well. In addition to texture, coatings such as TiN, CrN, and DLC may be applied. Of course, texture and coating may be used together.

[0182] Using a resin with high fluidity allows the pressure of the gas injected into the molten resin filled in the cavity that forms the hollow during hollow molding (injection hollow molding) to be reduced. With molten resin with high fluidity, the hollow part is formed at lower pressure, resulting in a hollow molded product with less warping and deformation. Reducing the pressure of the gas injected into the molded product allows for a hollow molded product with high dimensional accuracy. Using a resin with high fluidity reduces or eliminates hesitation marks, a defect unique to hollow molding, resulting in a hollow molded product with a clean surface.

[0183] In the case of compressed air molding (injection compressed air molding), using molten resin with increased fluidity reduces the melt viscosity, improving transferability to the mold. In the case of compressed air molding, transfer to the mold can be improved by inserting high pressure gas between the resin and the mold (also called "gas pressure holding"), and by using both gas pressure and resin pressure holding. In this case too, the gas pressurizing effect is greater when the resin temperature is set higher, and the Kanabata temperature is also set higher. The gas pressurizing effect is even greater in heat and cool methods, such as BSM using high frequency induction heating. In the case of compressed air molding, it is very effective when a printed film is placed in the mold first for molding transfer.

[0184] In the case of resins whose fluidity has been increased by using a liquid, it is possible to improve the transferability to a mold even in general molding. Resins with high fluidity have the effect of improving the transferability to a mold.

[0185] To increase the fluidity of resin, it is mixed with low molecular weight resin, or polymer alloy or polymer blend with other resin. Fluidity improvers such as wax, stearic acid, and stearates are used, but the unit price of the resin increases, making it uneconomical, and the deterioration of the physical properties of the resin is unavoidable due to these additives. In the case of liquids, they are squeezed out of the molded product due to resin pressure retention, so they do not affect the physical properties of the resin. Also, the liquids used are not expensive, so there is little or no economic problem such as a large increase in the resin unit price. Office equipment and other products require high flame retardancy such as V0-5VA or B, and are increasingly being made thinner in order to reduce the amount of resin used. For thin-walled molded products using this type of resin, molding machines with large mold clamping forces are used, and molding is carried out at high pressure and high speed, but problems such as burrs on the PL and a short mold life occur. For molded products to be painted, higher pressure and long dwell times are used to eliminate sink marks. In this case, too, these issues can be easily resolved by using resin with increased fluidity using a liquid, and all at once these issues are resolved. EXAMPLES

[0186] It was shown that the fluidity of molten resin is greatly improved when a large amount of liquid is injected. However, if molding is performed in this state, no matter how much the resin holding pressure or mold temperature is increased, swirl marks will appear on the surface and a molded product with a clean, smooth surface cannot be obtained. If a GCP is used, swirl marks can be eliminated. It was confirmed that when the GCP in the mold is used to vent the pressurized gas in one go and molten resin with increased fluidity is used, there are fewer short molds compared to when a GCP is not used. It is believed that this is because the GCP creates negative pressure in the mold in a short time, reducing the number of short molds. In Fig. 61, an aspirator is attached to the mold, and the pressure in the mold is made negative by using the process of exhausting the compressed air in the mold. Numeral 279 indicates the seal mold for GCP shown in Fig. 20, etc., and compressed air is applied to the mold by opening valve 280. Numeral 281 indicates the compressed air that is put into the mold, and numeral 282 indicates the compressed air circuit provided in the mold. Numeral 283 indicates the flow direction of the gas that first pressurizes the mold, and the mold is pressurized, and the valve 280 is closed during or after the filling of the resin that has been given foaming properties by liquid or the like or the resin that has been enhanced in fluidity is completed, and the check valve 284 is forcibly opened. Numeral 285 is indicated inside 284. A ball check valve is inserted, and 285 is normally closed by a spring (not shown) provided inside. A signal to open (exhaust) the compressed air inside the mold is transmitted to the hydraulic and pneumatic cylinder 286, and when the rod rod 287 connected to the cylinder is pushed, 285 is pushed up, and the compressed air is exhausted to the atmosphere from the aspirator 288. Due to the flow of exhaust gas from this exhaust gas, part of the compressed air inside the mold is drawn into 293, creating negative pressure inside the mold. 290 indicates the flow of the exhausted compressed air, 291 indicates part of the compressed air that passes through the aspirator 288 and creates negative pressure, and 292 indicates part of the compressed air inside the mold that is sucked in by the aspirator 288. The device 294 is an aspirator. When the compressed air inside the mold is passed through 295 and exhausted from 296, negative pressure is generated inside 294, and the gas is sucked into 294 from 297. The sucked gas is exhausted to the outside together with 296.

[0187] For example, molding materials such as ABS are dried at 80℃ for about an hour to avoid defects in appearance such as silver, but if GCP is used, beautiful molded products without silver can be obtained even when molding general materials without drying and improving fluidity using liquid. If foam molding is not performed, there is no need to worry about the foam cells being crushed by the pressure of the GCP, so the GCP can be high pressure, such as 1MPa, 2MPa, or even more. Being able to mold without drying saves electricity and reduces carbon dioxide gas. EXAMPLES

[0188] We confirmed a method of cleaning the inside of the heating cylinder by putting liquid into it and vaporizing it. When changing from black PP to white PP, purging materials (cleaning agents) such as Asaclean (trade name) and Z Clean (trade name) are generally used, but these purging agents are expensive, which is an economic problem, and there is also the problem of the purging agent remaining behind. It is also known to add a small amount of chemical foaming agent, such as baking soda, ADCA, or DPT, to the purging agent to increase the cleaning effect through its foaming power, but there is a problem of the foaming agent residue remaining behind in the heating cylinder.

[0189] In Example 28, it was confirmed that the cleaning effect is higher than that of the commercially available purging agent by using a small amount of liquid when changing materials and colors, without using the commercially available purging agent. When measuring, liquid such as alcohol or water is poured into the liquid injection port during foam molding using the liquid of the present invention, and vaporized by the temperature of the heating barrel and the temperature of the molten resin, and the molten resin is purged with foaming properties. At this time, the pressure inside the heating barrel increases due to the gas vaporized from the liquid, so the cleaning effect is enhanced. When the same operation (start of measuring, liquid injection, completion of measuring, liquid injection stop, injection, etc.) is repeated, a high cleaning effect was confirmed. When a liquid made by mixing IPA and water in a 1:1 ratio is used in the heating barrel at 2 wt.% relative to the amount of measured resin. When changing the color of the PP from black to white, the amount of white PP used was less than half that of the resin to be molded next (white PP). Unlike baking soda, ADCA, etc., when only liquid is used, there is no foaming residue, so there is no problem of undecomposed foaming agent or foaming residue remaining inside the heater barrel or nozzle.

[0190] The liquid used for cleaning can be just alcohol such as ethanol or IPA, but it can also be alcohol mixed with water. Adding a small amount of surfactant (ionic, nonionic, anionic, cationic, amphoteric, nonionic), such as sodium alkylbenzene sulfonate (soda) (the abbreviation is the same as for resin, "ABS"), to alcohol or a mixture of alcohol and water has a cleaning effect. The cleaning effect can be further enhanced by adding sodium bicarbonate and dissolving it in water. In this case, since the sodium bicarbonate is dissolved in water, there is little sodium bicarbonate or sodium carbonate, a decomposition product of sodium bicarbonate, remaining inside the heating tube and in the nozzle.

[0191] Of course, the liquid may be used in combination with the commercially available purging agent, which has the economical effect of reducing the amount of the commercially available purging agent used.

[0192] Since this is a purge, it is okay if the nozzle is open and drooling. In the case of a hot runner, cleaning (purging) with a liquid that leaves no foaming agent residue is good for cleaning the inside of the manifold and nozzle, and for subsequent resin replacement. Although only liquids have been explained, gases that leave no foaming agent residue can also be used. Good gases include nitrogen gas, carbon dioxide gas, liquefied carbon dioxide gas, and dry ice. A combination of gas and liquid is also good. To further enhance the cleaning effect, there is a method of using resins with added glass fiber or talc, such as AS with glass fiber, or high-viscosity resins such as PC in combination with liquid to enhance the cleaning effect.

[0193] If liquid is injected into the molten resin in the nozzle during injection and vaporized by the heat of the nozzle, the nozzle can be easily cleaned. Of course, gas can also be used. However, it has been confirmed that liquid has a higher cleaning effect than gas. Example 28 was explained using an injection molding machine, but it is not limited to injection molding machines, and can also be used for purging and color changing of extruders, etc. To clean (purge) the inside of the hot runner, a liquid and / or gas inlet (with the same structure as the injection port on the heater barrel) is provided on the manifold and the hot runner can be purged by injecting liquid and / or gas there. Apart from purging by injecting liquid and / or gas from the manifold, if liquid and / or gas is injected from the nozzle of the injection molding machine, the action and effect will not be much different from injection from the manifold. In addition, by injecting liquid and / or gas directly into the manifold of the hot runner like this, the inside of the hot runner can be cleaned with liquid and / or gas. Naturally, if the resin is filled into the cavity, foam molding will occur, but if the foam cells are crushed using a holding pressure, it becomes general molding, which can also be expected to improve the fluidity of the molten resin using liquid and / or gas. In the case of a mold with a hot runner, there is a method for injecting liquid and / or gas into the manifold. EXAMPLES

[0194] As interest in environmental issues grows, the demand for energy saving in resin processing is also increasing. In this Example 29, a resin that is not dried (drying-less, resin processing is performed as is without drying at all) is used, and appearance defects such as silvering occur on the surface of the molded product due to not drying, the moisture on the surface and inside of the resin, and the volatile components of the resin (solvents used in the resin manufacturing stage, resin monomers, dimers, trimers, etc.). The above-mentioned silvering problem can be solved by using a GCP with an appropriate pressure.

[0195] Even in general molding (in this invention, after filling the cavity with molten resin, the volume that is reduced by cooling and solidification is pushed in with an appropriate pressure, which is called "resin holding pressure", and molding processing methods that use this resin holding pressure are called general molding, general processing, solid molding, solid processing, etc.), it has been confirmed that the use of GCP eliminates the silver caused by the moisture and volatile components, and makes the surface of the molded product clean and smooth. This experiment demonstrated that by using GCP, defects such as silver on the surface of molded products can be eliminated even when using a molding material that does not require drying.

[0196] For example, if ABS (Clarastic GA501 (product name and grade) manufactured by Nippon A&L Co., Ltd.) is molded without drying, the moisture absorbed by the ABS resin pellets will cause silver to appear on the surface of the molded powder, making it unsuitable for use in exterior parts. Even if the product is painted, the silver on the surface of the molded product will significantly reduce the adhesion of the paint film, which is a problem. By performing GCP using a sealed mold as shown in Figures 1 and 2 (sealing means can be either a means for sealing the ejector pin or an ejector box structure. Figures 1 and 2 show the ejector box specifications), it is possible to obtain ABS molded products with a good appearance and no silvering, even without drying.

[0197] The ABS (which has absorbed water) that had been stored in a warehouse for about 3 months was used in a general molding process without GCP using the GCP specification sealing mold shown in Figures 1 and 2. As a result, a lot of silver was generated on the surface of the molded product, resulting in a poor appearance and not meeting the customer's requirements.

[0198] Next, the air compressed inside the mold by a compressor was used to pressurize (pressurize, pressurize) the pressure inside the mold to about 0.8 MPa using the GCP device shown in Figure 15, and the undried ABS was filled into the cavity. At the same time as filling was complete (resin dwell pressure is applied from the heating barrel, but in this case this was done after the primary pressure was completed), the compressed air (GCP) air inside the mold was released into the atmosphere. Resin dwell pressure continued to be applied even after the compressed air was released. There was absolutely no silver generation on the surface of the ABS molded product obtained through this process, and the surface of the molded product was clean, smooth and of good quality, fully satisfying customer requirements.

[0199] Next, the ABS was immersed in tap water for 12 hours, and absorbed water until it was saturated (about 0.5wt% water was absorbed). The absorbed ABS was scooped up and placed in a fine net for dehydration. As a result, the ABS contained about 0.5wt% water. When the absorbed ABS was molded in the same manner using the molds shown in Figures 1 and 2, a lot of silver was generated on the surface of the molded product due to the absorption of water inside the ABS. Next, GCP was performed with a pressure of 1MPa, and as a result, no silver was generated on the surface of the molded product. This (general molding processing using materials that have been immersed in water and absorbed water) shows that if the GCP method is used, the material is not dried (without drying) and the molding process is performed as is, and there are no defects such as silver on the appearance caused by moisture, and this Example 29 demonstrates that molding processing is possible without drying the molding material by using a seal mold and the GCP method.

[0200] Other than ABS, it was confirmed that even with non-drying HIPS {Toyo Styrol H450 (product name and grade) manufactured by Toyo Styrene Co., Ltd.}, modified PPO(E) {NORYL SE90 (product name and grade) manufactured by SHPP Japan LLC (formerly Sabic Japan LLC)}, PC {SD Polyca 301-22 (product name and grade) manufactured by Sumika Polycarbonate Co., Ltd.}, PCABS {Techniace PAX-1439 (product name and grade) manufactured by Nippon A&L Co., Ltd.}, and PP {Sumitomo Noblen AW564 and Z744 (both product names and grades) manufactured by Sumitomo Chemical Co., Ltd.}, the surface of the molded product obtained by GCP (if GCP is implemented) is free of any defects such as silver, and can be made beautiful and smooth.

[0201] Although not shown, the mold of FIG. 44 incorporates specifications for carrying out the pressure molding shown in FIG. 26 and specifications for carrying out the blow molding of FIG. Using the mold shown in Figure 44, the ABS, HIPS, modified PPO(E), PC, PC / ABS, and PP were subjected to GCP at 1 MPa without drying each of them, and blow molding was carried out. Pressure molding was also carried out. Furthermore, blow molding and pressure molding were carried out simultaneously, and it was confirmed that the silver disappeared.

[0202] Air is generally used as a GCP, but in the case of materials that cause discoloration or burning, discoloration and burning can be prevented by using nitrogen gas instead of compressed air (it is sufficient to simply lower the oxygen concentration in the compressed air to 15 vol% or less, for example).It has been confirmed that when carbon dioxide gas (a mixture of compressed air and carbon dioxide gas is also possible) is used as a GCP, the carbon dioxide gas dissolves into the molten resin filled in the mold cavity from the flow front, improving the fluidity of the molten resin. We carried out blow molding with ABS and HIPS, which have improved fluidity by using liquid. We also carried out pressure molding. We also carried out a combination of blow molding and pressure molding.

[0203] (Embodiment 1) From Comparative Examples 1 to 4 and Examples 1 to 5, it can be seen that if a PC resin is used, and water is used as a foaming agent and aluminum oxide, silver oxide, silicon dioxide, or silicon carbide is used as a foaming nucleating agent, it can be carried out not only with an injection molding machine but also with extrusion molding, and if the foamable resin coming out of the die (extruded) is passed through a gas (which can be air, nitrogen gas, or carbon dioxide gas) with a pressure of 0.6 MPa or more, and the principles and means of GCP are also applied to extrusion molding, it is possible to suppress foaming on the surface and achieve extrusion molding without swirl marks.

[0204] (Embodiment 2) In Examples 1 to 5 and in Embodiment 1, it has been described that water is used as the foaming agent, but even in the case of Musel, Amotech, and Sofit (product name?), which are foam molding products using gases such as nitrogen gas and carbon dioxide gas, the foam nucleating agents such as aluminum oxide, silver oxide, silicon dioxide, and silicon carbide exemplified in this invention use PC-based resins, and the action and effect of the foam nucleating agent is fully exerted when implemented in injection molding, extrusion molding, and blow molding.

[0205] (Embodiment 3) The present invention adds to and asserts that the present invention encompasses all of the parts involved in foam molding (GCP devices, sealing molds, molding machines, and ancillary equipment such as shut-off nozzles) contained in PCT / JP2015 / 062611, PCT / JP2015 / 069216, PCT / JP2016 / 086380, and PCT / JP2020 / 015536.

[0206] (Embodiment 4) In the foam molding of PC resins, the foaming agent used in the examples of this invention is water, and there are many other foam nucleating agents that can be used other than aluminum oxide, silver oxide, silicon dioxide, and silicon carbide, as long as they do not decompose PC. Mix wet PC (water-absorbed PC) with another foam nucleating agent (spread it on the PC surface with a small amount of water), and use an injection molding machine to mold test pieces to check for any significant decrease in physical properties (decomposition of PC). If there is no significant decrease in physical properties, it can be judged to be a usable foam nucleating agent.

[0207] (Embodiment 5) (Methods for increasing foaming ratio) In foam molding, the means for increasing the expansion ratio include increasing the amount of foaming agent added to increase the foaming power of the resin, filling the cavity with foamable resin and expanding a part of the mold to reduce the pressure of the filled foamable resin to make foaming easier, lowering the screw to reduce the pressure of the foamable resin to make foaming easier, and opening the mold to increase the expansion ratio. When opening the mold, the mold structure can be either flat parting (mold structure shown in Figures 11 and 12, movable side mold retraction movement) or vertical parting (mold structure shown in Figures 13 and 14, movable side mold retraction movement). The former is called mold back and the latter is called core back, and they are distinguished in this invention. When the mold back is opened widely, there is a risk of flash occurring on the PL, so it is not opened very widely. In the case of core back, there is less risk of flash occurring on the PL, so a molded product with a large expansion ratio can be obtained.

[0208] (Molding equipment) This embodiment 5 can be implemented in either mold back or core back. There are two-plate and three-plate injection molds (mold structure). When mold back or core back is performed with a two-plate mold, the movable die plate of the injection molding machine is moved back a predetermined amount (distance) to expand the cavity (mold, cavity) and increase the foaming ratio. In general injection molding, when a three-plate mold is opened, if the PL opens first, it may be difficult to open the stripper plate (the sweeper plate for the spool runner), so it is common to provide a PL lock mechanism for the PL and open the fixed mold plate and stripper plate first. However, even if the movable die plate of the injection molding machine is moved back with this mold structure, the stripper plate opens due to the PL lock, and mold back or core back is not achieved. As a means of solving this problem, the inventor does not use a PL lock, but instead fits a spring or urethane rubber into the PL, and by moving the movable die plate back a predetermined distance, the spring or urethane rubber will always open the PL first, allowing mold back and core back. A gas spring can be used instead of a spring or urethane rubber. A hydraulic cylinder or pneumatic cylinder can also be used. The inventor called this a "first mold opening mechanism, first mold opening mechanism." After the mold back and core back are performed to increase the foaming ratio, and cooling and solidification are completed inside the mold, the die plate is lowered (retracted) to remove the foam molded product, but since there is no PL lock, the stripper plate does not move and the spool runner does not leave the mold. At this point, the inventor pulls the movable mold and the stripper plate using a pull ring, pull bolt (rod), chain, or chain, etc., and uses the mold opening to move the stripper plate and remove the spool runner from the mold (mold release). Measures are taken to ensure that tension rings, chains, and other fasteners do not break or snap when the mold is opened (for example, a spring is installed in the tension bolt). In addition to directly connecting the movable die and the stripper plate with a tension ring or the like, the movable die and the fixed die may be connected with a tension ring or the like, and the fixed die and the stripper plate may be connected with a tension ring or the like. Figures 6 and 7 show a three-plate type that uses the above-mentioned tension ring, but in the case of a two-plate type, a spring, urethane, etc. can also be installed on the PL, and if installed, the mold back and core back can assist in retracting the mold.

[0209] This mold structure can also be implemented in the case of GCP. It is also effective for molds with a back-chamfer structure (a mold structure of three or more plates) (such as stack molds), and just like with three-plate molds, springs, urethane rubber, etc. can be installed on the PL of each product surface so that they always open first when the die plate retracts. In this case, if a seal mold is used, GCP can be performed and a foam molded product with a clean surface without swirl marks and a smooth GCP with a high foaming ratio can be obtained. The mechanism for opening the PL first can also be implemented in a mold with a built-in hot runner. In this case, it is preferable for the hot runner to have an opening and closing mechanism (valve) such as a spring or needle type.

[0210] In the case of stack molding, generally, horizontal injection molding machines are also possible, but when injecting foamable resin from PL, injection molding machines with vertical clamping mechanism and horizontal injection mechanism (generally called vertical injection molding machines) are used. In this case, for stack molding of PL injection, shut-off nozzles with spring-type or needle-type opening and closing mechanisms are used. In this way, for foam molding products suitable for stack molding, the foam molding process is an effective means of increasing productivity, especially for flat shapes (flat plate shapes, shapes close to flat plates) such as IC trays used to transport semiconductors in semiconductor manufacturing plants. In the case of IC trays, conductivity is required, so conductive carbons such as Ketjen Black and acetylene black, carbon nanotubes (CNTs), etc. are added. Polymer alloys mainly composed of m-PPO and PC resins with high heat resistance are used for molding. PC resins may be used alone, and the type of resin is not important as long as the heat resistance requirement is met.

[0211] Usually, foam molding does not use holding pressure, or if it does, it is for a short time, so there is no need to precisely balance the filling of each molded product (cavity). It is sufficient to fill the cavity almost to the brim with foamable resin, or more than 70 of a cavity's volume being 100. A short mold is acceptable since mold back and core back will be used. Even if it exceeds 100, mold back and core back will occur, so the final volume will never exceed 100. Each cavity is filled with foamable resin at approximately the same time (the filling conditions are the same), but separate filling using sequential control is also acceptable.

[0212] The foam molding performed in this embodiment 5 is foam molding using an injection molding machine, and the properties of the substance that gives the resin foamability, the so-called foaming agent, can be applied to all of the following foam molding techniques: techniques that use gaseous substances, for example, compressed gas such as Mucel or Amotec, liquefied carbon dioxide, techniques that use liquid substances such as alcohol or water in NPT, microballoons, macroballoons, microballoons, bicarbonates such as baking soda, azo compounds such as ADCA, and nitroso compounds such as DPT.

[0213] In the case of IC trays, if a chemical foaming agent is used, there is a risk that the foaming gas and foaming residue will have a negative effect on the IC and the plated legs of the IC, so it is necessary to check thoroughly. There is no problem with foaming molding using gas or liquid, as the foaming residue will not be mixed into the molded product. In fact, the inventor used a mold for IC trays shown in Figure 10 (photo), m-PPO containing acetylene black as the molding resin, and water, ethanol, propanol, a mixture of water containing 40 wt.% ethanol, a mixture of water containing 40 wt.% propanol, and a mixture of ethanol and propanol in a 1:1 ratio as the foaming agent. Approximately 1 wt.% of the resin (molded product) was placed in a heating cylinder, vaporized to become a foaming resin, and foaming molding was performed without GCP, resulting in a weight reduction of about 6 to 10%. When GCP was used, the weight reduction was about 5 to 8%. The impact strength of each molded product was approximately 70% lower without GCP and only 25% lower with GCP, assuming the impact strength of the solid (solid, general, solid, general) molded product to be 100. The above examples were performed with m-PPO, but similar results are expected with PC resins. In this case, water is the most suitable blowing agent. In terms of heat resistance and cost, the molding material suitable for IC trays is preferably a conductive resin whose main component is m-PPO or PC resin, and when the heat resistance requirement is not so high, a conductive resin whose main component is a styrene resin such as ABS may also be used.

[0214] As a result of molding back 25% of the plate thickness (wall thickness) of the molded product, molded products without GCP and with GCP were obtained, with a weight reduction of about 25%. In this case, the impact strength of the molded product was further reduced, but this can be solved by adding graft rubber (a binary copolymer in which styrene is graft-copolymerized with butadiene rubber) contained in m-PPO in advance, assuming a decrease in impact strength. It is also possible to increase impact strength by increasing the particle size of the rubber, and in this case, using graft rubber with a different particle size will further improve impact strength. After the mold has been backed up, the mold can be closed a little again to compress it. After this, the mold must be opened and the molded product must be brought to the movable side (the side pushed out by the ejector pin), but depending on the shape, it may be taken to the fixed side. In this case, undercut or texture the side of the movable mold to ensure that it is brought to the movable side in a balanced manner.

[0215] The impact strength can be further improved by using EPDM {ethylene rubber (ethylene-propylene-diene monomer)} instead of butadiene rubber. EPDM has a much higher thermal stability than butadiene rubber, and m-PPO using EPDM graft rubber has high recyclability (there is little deterioration in physical and mechanical properties even if it is repeatedly recycled and subjected to heat history). When manufacturing m-PPO, PPO and rubber grafted with PS are melt-kneaded, but using a reduced volume of discarded polystyrene foam (the component is PS, and it is possible to use it because it is foamed using pentane, which does not leave a foaming residue), instead of PS, can contribute to reducing the environmental load. If necessary, a general foam nucleating agent or the foam nucleating agent of the PC resin described in this invention may be used. Since IC trays are made by mixing conductive materials such as acetylene black into m-PPO, acetylene black also acts as a foam nucleating agent. PC resin may be used instead of m-PPO.

[0216] Using the mold shown in Figure 10, a resin made by giving electrical conductivity to PC{SD Polycarbonate (product name) 301-15 (grade) instead of m-PPO was foam-molded using ion-exchanged water, and it was confirmed that foam-molding was possible in the same way as m-PPO, and that weight reduction was also possible. The conductive carbons such as Ketjen black and acetylene black, which impart electrical conductivity, acted as bubble nucleating agents. Trials with CNT also showed that CNT also acted as a foam nucleating agent, and therefore these conductive materials that impart conductivity are effective as foam nucleating agents for molded products that require conductivity, such as IC trays, and can therefore be used satisfactorily.

[0217] (Embodiment 6) In addition to mold backs and core backs, breathing (expanding) cores and dummy shapes are used to facilitate foaming. First, we will explain the expansion core. Figures 37 and 38 show an example of a dummy shape (a throw-away shape, a throw-away cavity) with a shutter. The shape is the opposite of a submarine gate. When resin is filled in the inside of reference number 4 and part or all of reference number 172 is filled with resin (Figure 37), the rod rod connected to the ejector plate of the mold reference number 168 retracts (Figure 38) immediately or after a certain period of time has passed. At that time, reference number 173 appears. Reference number 137 is connected to the dummy shape 171 from the gate reference number 170, so the molten resin in reference number 4, which has pressure (residual pressure), flows into reference number 171 through reference number 172, reference number 173, and reference number 170, and as a result, the pressure of the resin in reference number 4 decreases, making it easier to foam. Reference number 168 is a mechanism that moves using an ejector rod (for forward movement) and a spring (for backward movement) built into the mold, for example, in the same way as ejector plates (B) and (C). If ejector plates (B) and (C) are built into the mold, reference number 168 may be a new ejector plate (D). Ejector plate (D) may have a two-plate structure, one above the other, like (B) and (C), but it can also be a single plate since it is simply provided with a pin. Figures 37 and 38 show the reverse structure of a submarine gate (closed at first), but reference number 170 can also be implemented with other shapes.

[0218] (Embodiment 7) By using this rod structure and mechanism, automatic gate cutting can be easily performed in foam molding, blow molding, and pressure molding that do not use pressure holding. Figures 39, 40, and 41 show the structure of automatic gate cutting. Reference number 175 is the gate of the molded product of reference number 4, and its shape is a loading gate (Figure 39). Resin is filled into reference number 4, and immediately or after a certain period of time, when the rod rod connected to the ejector plate of the mold of reference number 177 advances, reference number 175 is pushed into the molded product of reference number 4 (Figure 40). As a result, the spool runner and gate are separated from the molded product 4 (Figure 41). In this case, there is no limit to the height or width of the gate, and in the case of a wide gate, a plate wider than the gate width can be used, with the tip of reference number 177 adjusted to the gate width. In blow molding and pressure molding, automatic gate cutting prevents backflow of the pressurized fluid injected into the spool runner. There are no restrictions on gate width for automatic gate cutting in foam molding, blow molding, pressure molding, etc., and the latitude of molding conditions is greatly expanded. Since holding pressure is not used in foam molding, blow molding, and pressure molding, and even if it is used, it is only for a short time, automatic gate cutting shown in Figures 39 to 41 can be easily implemented.

[0219] Next, we will show a method for reducing the pressure of the molten resin filled in the cavity to facilitate foaming in foam molding using a dummy shape (a throwaway cavity) without a shutter. In Figure 42, the shapes indicated by 181 and 182 are dummy shapes connected by reference number 180. Part of the dummy shape is filled with resin (reference number 181), and the part indicated by reference number 182 is actually filled, which is a so-called short mold, so the pressure of the filled resin in reference number 4 is reduced and foaming occurs easily, resulting in a foam molded product with a high expansion ratio.

[0220] In the case of blow molding and pressure molding, the dummy shape indicated by reference number 183 must be fully filled (fill the space of 183 with resin). In the case of blow molding, the pressurized fluid put into the molded product advances toward the part with low pressure, so if reference number 183 is a short mold like reference numbers 181 and 182, the pressurized fluid will escape from there and sufficient hollow space cannot be formed. Pressure molding is a molding method in which pressurized fluid is put into the gap between the resin and the mold and the other side is pressurized with that pressure. In this case, too, if reference number 183 is a short mold, the pressurized fluid will escape from the end of the short mold, so sufficient pressurization effect cannot be expected. The dummy shapes indicated by reference numbers 181, 182, and 183 are more suitable for the purpose of reducing pressure if they take a longer time to cool and solidify, so the thickness of this part is often made two or three times thicker than the thickness of reference number 4.

[0221] (Embodiment 8) Super engineering plastics such as PPS (polyphenylene sulfide), PES (polyethersulfone), and PEI (polyetherimide) are thermoplastic resins with high melting temperatures. When foam molding is performed using low boiling point solvents such as ethanol (ignition point temperature at 1 atm is about 400°C), iso-propanol, and hydrocarbons such as alkanes as foaming agents, if the ignition point of these liquids is higher than the temperature of the molten resin, there is a risk of fire, and discoloration and burning of the resin are expected. In other words, nitrogen gas replacement is performed in the hopper. Also, if air is used for the outer GCP, the temperature of the resin is still high, and if the temperature rises further due to adiabatic compression, discoloration and burning of the resin are a concern, pressurize with inert nitrogen gas instead of air. Carbon dioxide is fine.

[0222] (Embodiment 9) Foaming agents that are insoluble in water or alcohol, such as ADCA powder and HDCA powder, will precipitate (sediment) if simply placed in water or alcohol, due to their low viscosity. In order to slow down the rate of precipitation as much as possible, a varnish with increased viscosity is used in combination. If the resin to be foamed is PP, a solvent-based or water-based varnish for maleic acid-modified PP is used. If the resin to be foamed is ABS, for example, a varnish made from AS or ABS using a solvent (e.g., n-butanone) is used, and if the resin to be foamed is HIPS, a varnish made from PS or HIPS in the same manner as AS or ABS is used. In the case of styrene-modified acrylic resin varnish, both ABS and HIPS can be used. If a low-boiling point solvent is used, the inside of the hopper is replaced with an inert gas as shown in embodiment 8.

[0223] (Embodiment 10) The water holes (cooling circuits) of the mold used in the present invention will be described. Generally, water holes are drilled using a gun drill, but they are straight and curved (the distance from the molded product is uneven), so the heat exchange rate is not very high. By using heat bonding {Yamatec Co., Ltd. 3-3-5 Mizuho-cho, Nishitama-gun, Tokyo 190-1232 TEL: 042-557-5660} and heat melt bonding, a water circuit with a high heat exchange rate can be created. Specifically, an optimal cooling circuit is created on the surface, for example, with a milling cutter or by electric discharge machining. This is called the first insert. Next, a insert with a shape to cover the first insert is machined. This is called the second insert, and the first insert is covered with the second insert, and the surfaces are joined using heat bonding or the like to create a curved water circuit inside. The shape of the insert and the optimal flow path of the water hole are designed (calculated) in advance using CAD or the like. A water circuit is created in the hexahedral first mold before the insert is shaped, and also in the hexahedral second mold as necessary, and then a hexahedral body with a water circuit inside can be made by heat bonding. This hexahedral body can then be used to machine the shape designed in advance using CAD using conventional means. The reason why the first insert and the second insert are made hexahedral is that the bonding strength is increased if the bonding surfaces have as high a surface accuracy as possible (for example, polished surfaces are better than milled surfaces). Although a hexahedral shape is used in the tenth embodiment, the shape is not limited to this.

[0224] (Embodiment 11) (Liquid foaming agent that generates nitrogen gas) Compounds that generate nitrogen gas with high foaming power include azides such as sodium azide (NaN3), azo compounds such as ADCA, and nitrosates such as DPT. Inorganic sodium azide is water-soluble, but NaN3 begins to decompose when dissolved in water, so aqueous solutions of sodium azide cannot be stored for long periods and are therefore not suitable as liquid foaming agents. ADCA derivatives that are soluble in alcohol include esters of ADCA, such as ADCA diethyl {DEAD(CH 10 There is a DEAD (N2O4) which can be used as a liquid foaming agent. ADCA isodipropyl (DIAD) is also soluble in ethanol, and an alcohol solution of DIAD can be used as a liquid foaming agent in the same way as the alcohol solution of DEAD mentioned above. Simply putting ADCA powder in alcohol such as ethanol and pulverizing it using a mill or the like will create a slurry, which can be used as a liquid foaming agent that generates nitrogen gas in the foaming gas containing ADCA.

[0225] Polyvinyl alcohol (PVAL) is compatible with thermoplastic resins due to its molecular structure. Polyvinyl butyral (PVB) is a thermoplastic resin that exhibits high adhesion to glass, metal, ceramics, etc., and is compatible with thermoplastic resins. Both (PVAL, PVB) can be used to create a highly viscous liquid using alcohol and water, so if ADCA powder is dispersed in these, it becomes a slurry containing ADCA, which becomes a liquid foaming agent.

[0226] If maleic acid-modified PP varnish is thickened and ADCA powder is suspended, it becomes a liquid blowing agent for PP, and if ADCA powder is suspended in styrene-modified acrylic resin varnish, it becomes a liquid blowing agent for styrene-based resins such as HIPS and ABS. To thicken these maleic acid-modified PP solutions and styrene-modified acrylic resins with ADCA slurries, the thickener carboxymethyl cellulose (CMC) can be used. In addition to ADCA, air bubbles can also be dispersed. Naturally, inorganic hydrogen carbonates such as sodium bicarbonate can also be used. Cellulose nanofibers (CNF) can also be added to thicken the mixture. CNF also acts as a foam nucleating agent in foam molding.

[0227] The chemical structure of ADCA shows that two molecules of urea can be combined. When combined with urea, this substance may become water-soluble, since urea is water-soluble. If it is water-soluble, it can be used as a liquid foaming agent, and it will decompose thermally in the same way as ADCA, generating nitrogen foaming gas.

[0228] (Embodiment 12) In the two-cavity, paired molding of Example 20, the foamable resin may be filled into each cavity at once, or may be filled separately. The method of filling the paired molding and separate filling is described below. Let us assume that the molded products are A and B, and the amount of resin to be filled into A and B is measured in advance. First, the molded product A is filled, and the gate is switched to fill B. When A and B have finished cooling and solidifying, the mold is opened and each molded product is removed at the same time. First, the amount of molded product A is measured and filled into the cavity of A. After filling is completed, the amount of molded product B is measured again, and the gate is switched to fill B. When A and B have finished cooling and solidifying, the mold is opened and each molded product is removed at the same time. When this molding method is used, the mold clamping (mold closing), cooling inside the mold, mold opening, and ejection (molded product extrusion) are common, so the molding cycle is increased and productivity is improved. This method can also be implemented in the case of the blow molding of Example 21 and Example 22. After filling the cavity with foamable resin or non-foamable resin, the mold is closed and compressed, and then mold back or core back may be performed as necessary. The IC tray shape can be used as a so-called cassette mold, which allows the inserts of the molded product to be replaced while the mold is still attached to the molding machine in order to reduce mold costs. In this way, when switching between A and B molding, in addition to the mechanism for switching the gate, a valve-gate type hot runner can be used to open and close the valves respectively. This filling for switching between A and B is performed by a program in the molding machine's sequencer.

[0229] The foam nucleating agent for PC resin explained in this invention is used for extrusion foam molding using PC resin. The foaming agent used in this case is most preferably liquid water.

[0230] (Embodiment 13) The thirteenth embodiment shows the main problems of plastic recycling and the means of solving them. There are many technical challenges in plastic recycling, but the main ones are "color recycling", "restoring or maintaining physical properties", "reproducing dimensions", and "sorting". First, we will explain "color recycling". Plastics have low mechanical strength, but they are characterized by being inexpensive and mass-produced, and being able to be colored freely. This ability to be colored freely means that plastic products of various colors are offered on the market, so the color problem, that is, color reproduction, is one of the challenges that prevent plastic recycling from progressing. There are two means of recycling this color. One method is to collect only objects (molded products) of the same color, wash them, crush them, mix the crushed material with virgin pellets or powdered objects, re-pelletize them, and obtain a molding material with a certain amount of recycled material mixed in (about 10wt.% to 50wt.%). In this way, colors can be reproduced, but it is a means of recycling only plastic molded products of a specified color.

[0231] (Cleaning Method) Molded products collected from the market are often dirty and have been photodegraded by ultraviolet rays and other factors, resulting in discoloration. In such cases, the photodegraded parts (mainly the surface) are removed using shot blasting or other methods. The molded products are washed by placing them in water and scrubbing them with hands, or by inserting an ultrasonic vibrator and performing ultrasonic cleaning.

[0232] When a molded product is crushed in a crusher, sound is produced. A wet crusher is a crusher that utilizes this sound. When crushing is performed while injecting water or underwater, sound is produced (generated), and this sound is transmitted underwater, and dirt on the molded product surface is washed away by physical force (sound waves).

[0233] (Recycling colors using paint) When there are molded products of various colors, they are not color-sorted, but are crushed as they are, and the molding material is pelletized as necessary. The molding material is then molded as it is in the various colors, and the surfaces of the molded products obtained by molding the various colors can be painted to recycle them into molded products of the desired color. When using paint for coloring (decorative paint, cover mark paint), for example, if the resin that makes up the molded product is ABS, HIPS, or modified PPO, paint whose main component is styrene-modified acrylic resin that is compatible (soluble) with the resin that makes up the molded product is used. When a molded product with a coating film painted using the above-mentioned compatible paint is recycled, the coating film is not separated or peeled off, but is crushed with the coating film still attached, and if necessary, when the molded product is molded using pelletized molding material, the styrene-modified acrylic resin, which is the main component of the coating film, is compatible with the resin that makes up the molded product and melts into the resin at the pelletizing stage and / or the heating and melting stage of remolding, so there is less deterioration in the physical properties of the resin caused by the coating film mixing.

[0234] Since the styrene-modified acrylic resin is a resin that exhibits thermoplasticity, paints using this resin have low chemical resistance, and the coating film peels off in a rubbing test using alcohol, for example. When chemical resistance is required, paints whose main component is urethane resin (the urethane resin in the coating is thermosetting, while styrene-modified acrylic resin is thermoplastic) are often used, and although it is best to separate and peel off the coating of painted molded products that have been painted with paints whose main component is urethane resin, if the coating is not separated or peeled off and the product is pulverized with the coating still on, and then refined (for example, to an average particle size of 1,000μm or less, preferably 100μm or less) using an extruder capable of high-intensity kneading such as a twin-screw extruder or kneader, then the physical properties will not decrease significantly even if the urethane coating is mixed into the molding resin. In some cases, there may be no decrease compared to thermoplastic styrene-modified acrylic resin (in the case of styrene-modified acrylic resin, the dyes and pigments in the coating melt during the pelletizing and remolding stages, migrating into the resin and reducing the physical properties of the resin, but in the case of urethane resin, since it does not melt, the dyes and pigments in the coating remain in the coating and do not migrate into the resin, so there is less decrease in the physical properties of the resin).

[0235] The extruder with strong kneading may be a single screw, but preferably a multi-screw extruder (two or more) with one or several screws with dulmage. The screws may rotate in the same direction, but to improve kneading and refine the urethane coating, it is better to rotate them in opposite directions. PP is used extensively in automobile parts, so to paint PP molded products, a primer treatment is first performed using maleic acid-modified PP, and then a paint using a thermosetting urethane resin is used.

[0236] (Restoration of physical properties) In order to improve the physical properties of styrene resins such as ABS and HIPS, rubber that has been grafted with the resin components to be blended is blended. We will explain using ABS. ABS is a blend polymer made by blending (mixing) AS resin, which is a copolymer of A (vinyl cyanide) and S (vinyl phenylate), with a tertiary graft copolymer of A, S, and butadiene rubber, which is a graft copolymer of A and S grafted onto butadiene rubber. When ABS is molded, crushed, and remolded, the butadiene rubber in the tertiary graft copolymer of A, S, and butadiene rubber (brown butadiene rubber) undergoes thermal degradation and loses its rubber properties. As a result, repeated recycling reduces the physical properties of the resin, such as impact strength. The deteriorated physical properties of the resin can be restored by mixing in new grafted butadiene rubber. If the addition of grafted butadiene rubber reduces the rigidity of the resin, AS resin is mixed in to balance the resin and then recycled.

[0237] (Thermal properties of blowing agents) Here, we will discuss foaming agents suitable for recycling. Among solid foaming agents, inorganic foaming agents, such as bicarbonates typified by sodium bicarbonate, are thermally decomposed in the heating cylinder, and absorb heat when generating foaming gas. This is a so-called endothermic reaction. In the present invention, these are called "endothermic foaming agents". On the other hand, the thermal decomposition of organic foaming agents typified by ADCA and DPT is an exothermic reaction, and these are called "exothermic foaming agents". In the case of liquid foaming agents typified by water, alcohol, and hydrocarbon, the liquid is vaporized into gas in the heating cylinder by the heat, thermal energy, and / or temperature (heat, thermal energy) of the heating cylinder. These liquid foaming agents are "endothermic foaming agents". In foam molding using gas such as MU-CELL, AMOTECH, and SOFIT, there is no phase change, so they are neither endothermic nor exothermic foaming agents. Therefore, endothermic foaming agents do not apply thermal energy to the molten resin in the heating cylinder, and as a result, the physical properties of the resin are not reduced by the thermal action of the foaming agent. Heat-generating foaming agents cause significant thermal damage to resin, as evidenced by discoloration and burning of foam-molded products when DPT and other similar agents are used.

[0238] Therefore, when plastic recycling is repeated, endothermic foaming agents are better than exothermic foaming agents, considering the thermal damage to the molten resin. However, solid foaming agents are not suitable for plastic recycling due to the problem of undecomposed foaming agent and foaming agent residues in the foam molded product. Gas and liquid foaming agents are suitable for plastic recycling because there are no residues, but only liquid foaming agents can produce foam molded products with a clean, smooth surface at a GCP of about 1 MPa. Liquid foaming agents are optimal for plastic recycling. Moreover, since liquid foaming agents are endothermic, they do not cause thermal damage to the molten resin. It has been stated in this invention that the use of liquid improves fluidity. By lowering the melting temperature of the molten resin (such as the temperature setting of the heater in the heating barrel), foam molding can be performed at a lower temperature, which has the effect of preventing thermal stress and damage to the molten resin and reducing thermal deterioration. In addition, being able to perform molding even at a lower melting temperature naturally reduces carbon dioxide emissions.

[0239] The above content is not limited to foam molding, and the same can be said about improving fluidity using the liquid of the present invention (technical content). In other words, the fluidity of the liquid can be greatly improved. As with the above-mentioned foam molding, the molded product does not contain any residue caused by the liquid, and other actions and effects such as lowering the resin temperature during molding can be expected. Note that this content can be implemented not only in injection molding, but also in extrusion molding and other moldings.

[0240] (Maintaining physical properties) ABS has low weather (light) resistance due to butadiene rubber. AAS (ASA) and AES, which use acrylic rubber (AR) and ethylene propylene rubber (EPM, EPDM) instead of butadiene rubber, do not experience significant deterioration in physical properties like ABS, even if recycled repeatedly. As a simple means of confirming recyclability, the inventors used an injection molding machine equipped with a shut-off nozzle, set all zone temperatures to 220°C, and set the temperature of the molten resin to 250°C, melted and mixed the resin, and allowed it to remain in the heating barrel for 30 to 60 minutes to apply thermal stress to the molten resin in the heating barrel. After a specified time (e.g., 30 minutes) had passed, the resin was purged, the purged mass was submerged in water to cool, and the purged mass that had been cooled was crushed, and the crushed material was used to mold test pieces for evaluating physical properties, and the physical properties were evaluated (this means is called the "thermal degradation test" in this invention). As a result, the Izod impact strength was 0% to 5% for AES and less than 10% for AAS, but a significant decrease of more than 50% was confirmed in the case of ABS.

[0241] Similarly, in the case of PE (polyethylene), the retention test showed almost no decrease in Izod impact strength, which was almost the same as that of virgin material, and no significant decrease in physical properties was confirmed. PE has high thermal stability and can be said to be a resin suitable for recycling.

[0242] In the case of PP (polypropylene), based on its molecular structure, there is syndiotactic PP, isotactic PP, and atactic PP. Furthermore, the catalysts used during polymerization include Ziegler-Natta catalysts and metallocene catalysts. When thermal degradation tests were conducted on each of these, the reduction in Izod impact strength was only about 5% for all types of PP, and it was concluded that PP has high heat resistance and is a resin suitable for recycling.

[0243] Just as the surface of a molded product is always wet by absorbing moisture from the air, a permanently antistatic resin made by mixing polyetheresteramide with ABS (Toray Industries, Inc.'s PAREL (product name)) showed a drop in Izod impact strength of nearly 90% in heat degradation tests, so PAREL is not a suitable resin for recycling.

[0244] (Recycling aid) "Recycling aids" are materials and additives that restore recycled materials to their original physical properties. Resins that are added for the purpose of modifying properties to give them different properties are also recycling aids. For example, the impact strength of ABS decreases when recycled. In this case, adding half the same ABS can restore some of the physical properties. ABS, which is developed to reduce the impact of recycled materials, and the aforementioned AS are both recycling aids. AES has high thermal stability, so if AES collected from the market is mixed with recycled ABS, the physical properties of the ABS can be restored. In this case, AES is also a recycling aid in the broad sense, and HIPS, which is used to modify EPS, is also a recycling aid. In this way, the original resin and resin additives are defined as recycling aids in this invention. Paints used to restore color (such as cover marking molded products to a different color) are also recycling aids.

[0245] (Maintain dimensions) When recycled resin is subjected to heat history, some of the molecular chains are broken and become low molecular weight.Otherwise, if a recycling aid is added to restore the physical properties, the fluidity of the molten resin changes, so in injection molding, with the general injection molding method (a molding process in which molten resin is filled into the cavity and then pressure is applied to eliminate defects in the molded product such as sink marks), there is a large variation in dimensions (variation in molding shrinkage rate) and the dimensions are not stable like when virgin materials are used, and in the case of recycled materials, there is a large variation in dimensions and they are not stable. To solve this problem, if the molding methods that do not use pressure holding are used, such as foam molding (injection foam molding), blow molding (injection blow molding), and pressure molding (injection pressure molding), and if the main components (molecular structure) of the resin to be molded are the same, the molding shrinkage rate of the recycled material will be roughly the same as when foam molding, blow molding, or pressure molding is performed using virgin material, so when recycling, it is better to use foam molding, blow molding, or pressure molding rather than general molding.

[0246] When recycled materials (referring to either or both of the spools and runners at the molding site, defective moldings crushed and pelletized as necessary, and plastic moldings collected from the market) are mixed in, the fluidity changes, and in general molding, the effect of resin holding pressure changes. (When recycled materials are mixed in, the fluidity increases, so the effect of resin holding pressure is greater at the same pressure compared to virgin materials. There are differences such as larger warping and deformation, and higher molding shrinkage. This varies depending on the mixing rate of recycled materials and the recycling history {number of times recycled (number of turns)}.) When using molding materials that contain recycled materials, in order to reduce the difference in the above-mentioned holding pressure effect, if a liquid is used to increase the fluidity as explained in this invention, the holding pressure effect of the resin can be reduced regardless of whether the recycled content is high or low. (When the fluidity increases, the pressure applied by resin holding pressure is approximately the same regardless of whether the resin molecular chain is long or short.) This stabilizes molding.

[0247] (Sorting) When recycling, complete recycling is not possible unless it is possible to accurately determine what resin is used in the molded product to be recycled and what types and amounts of additives are blended into that resin. Below we will provide a detailed and concrete explanation of the preparations that need to be made in advance for recycling (sorting).

[0248] First, we will explain the resin that is the main component of the molded product, using ABS as an example. As mentioned above, ABS is a blend polymer, or polymer alloy, made by mixing a copolymer of A and S with grafted butadiene rubber. Here, AS can be manufactured into resins with various ratios depending on the polymerization ratio of A and S (A to S ratio). Naturally, resins with different molecular weights (e.g. number average molecular weight, average molecular weight, etc.) are manufactured depending on the polymerization initiator and polymerization terminator, and there are differences in the molecular weight distribution. Even with butadiene rubber, there are differences in the ratio of A to S and the grafting rate. Various particle sizes (bimodal type) are used for the grafted butadiene rubber that is mixed with AS. In this way, various types of ABS alone can be manufactured.

[0249] (Other additives) As mentioned above, dyes and pigments are used for coloring ABS. If flame retardancy is required, flame retardants (such as halogen-type or non-halogen-type) and flame retardant assistants are added. In addition, antioxidants, antioxidants, antiozonants, UV absorbers, light stabilizers, plasticizers, fillers, reinforcing agents, PVC stabilizers, lubricants, slip agents, internal mold release agents, anti-fog agents, antistatic agents, colorants (including the above dyes and pigments), coupling agents, preservatives, mold inhibitors, compatibilizers, modifiers, crystal nucleating agents, dispersants, light diffusing agents, and bubble nucleating agents in the case of foam molding ("resin additives" or simply "additives") are used as necessary, as described in the "Handbook of Rubber and Plastic Compounding Chemicals, Second Revised Edition {Rubber Digest Co., Ltd., Second Revised Edition, October 30, 1993}." These additives may be usable when the molded products containing these additives are processed and delivered to the market, but may be substances that should not be mixed in when they are collected from the market and recycled several years later. Let's take flame retardants as an example. In the past, flame retardants were generally made by using halogen compounds that use the negative catalytic action of halogens, such as brominated epoxy and TBBA (tetrabromobisphenol A derivative), and antimony trioxide as a flame retardant assistant, but these days, their use is being refrained from due to the problem of the generation of brominated dioxins and brominated benzofurans. Antimony trioxide is a hazardous substance, so its use is hesitant. When recycling today, if halides are contained like this, it is necessary to recycle separately.

[0250] However, as mentioned above, it is not possible to reliably grasp the information (type of resin, additives, etc.) necessary to implement recycling (equivalent recycling, higher-level recycling) just by looking at the molded product, so the resulting recycling ends up being lower-level recycling.

[0251] (display) As mentioned above, it is difficult to grasp the huge amount of information required for recycling only from the mandatory recycling mark, so the inventors have inscribed a barcode {: normal barcode, two-dimensional barcode (QR code)} on the mold in advance for molded products with a certain weight, for example, 100 grams (g) or more. The barcode contains the weight of the molded product required for recycling, information on the resin that is the main component of the molded product as mentioned above using ABS as an example, such as molecular weight, ratio of A to S, information on the additives mentioned above (type and amount added), and the weight of the molded product. A useful method is to write this information on the molded product, collect it from the market, and read it at the recycling stage, for example before washing or before crushing, and at the recycling stage, crush it after confirming that it does not contain any prohibited substances at the current time. Molded products that contain prohibited substances are not crushed and are stored in a separate location.

[0252] Since the amount of information is enormous, it is given to each molded product as a barcode, preferably a QR code (two-dimensional barcode). QR codes are preferable to barcodes because they can hold more information. A label (sticker) with the QR code printed on it is affixed. Alternatively, in the case of injection molded products, the QR code can be engraved into the mold beforehand, eliminating the need to affix a label (Figure 44). In the following, the present invention will be described using a QR code (see FIG. 48, reference number 206).

[0253] The information in the QR code is read by a barcode reader, and when the crushed material is crushed, it is possible to know what kind of resin and how much of the additives are contained in the crushed material after crushing. If this can be done, it is easy to use a computer, for example, AI (Artificial Intelligence), to add the necessary additives in the necessary amounts to modify the material. The previously mentioned QR code is displayed on the molded products made from the recycled material obtained in this way, with the next recycling in mind. This allows recycling to be repeated (meaning repeating the recycling generations {1st (1st turn), 2nd (2nd turn), 3rd (3rd turn), etc.}). Of course, the QR code information also includes the content (mixture ratio, etc.) of the 1st turn material and the 2nd turn material. In other words, the necessary information is always added as a preparation for future recycling. This allows future recycling to be carried out without any problems.

[0254] (Confidentiality) For example, the name of the resin manufacturer, the product name, the grade, and the detailed composition of the resin (such as the type and amount of additives) can be read from the QR code, so there is a risk that important confidential information of the resin manufacturer may leak to competitors, and this is not desirable as it is. To do this, it is necessary to encrypt part or all of the content contained in the QR code (for example, a combination of numbers and letters using prime numbers, etc.). The encrypted content is only stored within the AI, such as the type of resin, the type and amount of additives, and the weight of the crushed material (the total weight of the crushed molded products is the weight information of the molded products written in the QR code, or the weight of each molded product is automatically measured and entered into the AI.), and the AI ​​and the person operating the AI ​​(such as an operator) must be required to impose necessary security measures to ensure that this information is never leaked to other companies.

[0255] (Recycling) Specifically, recycling and resin modification are all carried out within the AI. The AI ​​checks and understands all information related to the resin and additives of the crushed material for recycling purposes, so if you instruct the AI ​​on what kind of resin properties the crushed material should be modified into, the AI ​​will perform calculations and calculate the type and amount of resin and the type and amount of additives (such as the type and amount of recycling aids) that need to be recycled. The type and amount of resin and the type and amount of additives calculated by the AI ​​are added to the crushed material in advance, and test pieces are molded and processed, and the physical properties are measured (quality control), and it is confirmed whether the results match the contents calculated by the AI ​​(the planned physical properties of the recycled material). If the results are good, the type and amount of resin and the type and amount of additives required for recycling are added, and the recycled material is manufactured using the necessary means (for example, melt mixing using a single-axis, multi-axis extruder with screws rotating in the same direction or in a counter-rotating direction, kneading, pelletization, etc.) The obtained recycled material is sampled to measure its physical properties, and these are compared with the physical properties confirmed before production to confirm whether the recycling has been completed to the desired physical properties.

[0256] ("Equivalent reproduction", "upper reproduction", and "lower reproduction".) For example, using the casing (molded product) of an office equipment printer to recycle it into the casing of the same office equipment printer is called "equivalent recycling." Recycling (remanufacturing) using something of equal value (the printer casing) to recycle it into something of equal value (the printer casing) is called "equivalent recycling." Since the main component of expanded polystyrene (for example, EPS) is PS (GP), it can be modified to HIPS (high impact polystyrene) by reducing the volume, crushing it, mixing it with butadiene rubber made by grafting styrene with butadiene rubber, and pelletizing it. In this way, using a low-grade material such as EPS and modifying it with HIPS to make a higher-grade HIPS that is more valuable than EPS is called "high-grade recycling." By mixing this HIPS with PPO (polyphenylene oxide) and adding a flame retardant, it is possible to produce the same Noryl (brand name) using EPS. However, currently, management is not carried out using the QR codes and other methods described in this invention, and the resins and additives in the molded products are not known. Therefore, when the resins are crushed without being separated into different types and used as resins to process artificial wood, flower pots, etc., this is called "lower-level recycling." Since molded products collected from the market are combustible, if they are recycled as fuel in cement factories, steel mills, thermal power plants, etc. to produce thermal energy (a lower-level type of energy), this is considered lower-level recycling and will be a one-time process. This is also "lower-level recycling."

[0257] (Recycling method flow) The actual flow of plastic recycling using this invention is shown below. Virgin resin is used for molding, and painting is applied as necessary. Molded products marked with QR codes are supplied to the market, and are collected once their role is completed. The QR codes and other methods shown on the molded products are used to check whether they are recyclable and whether they contain any substances that inhibit recycling. Recyclable molded products are washed as necessary, or any deteriorated surface areas are removed using blasting or other methods.

[0258] When items of the same material and color are collected, they are crushed, the necessary recycling aids calculated by AI are added, and the items are tumbled to make them uniform, pelletized, and reused as recycled material. In this case, the amount of recycled resin contained, the amount of each additive, and the amount of recycling aid are recorded on the molded item using a QR code or similar, since the molded item will be recycled again in the future.

[0259] Even if they are not color-coded and are crushed as they are, with the QR code, only those molded products that are judged to be recyclable are crushed, and the AI ​​checks the type of resin and the type and amount of additives contained in the crushed material, and in the same way, recycling aids and other additives are added, tumbled, pelletized, and remolded. The resulting molded products can be used as they are, with mixed colors, but if coloring is required, they are painted as a cover mark. Of course, this molded product is engraved with a QR code that contains information on the type and amount of recycling aids and other additives, including the fact that it has been painted, with the assumption that it will be recycled using the QR code.

[0260] In this way, by using a QR code on a molded product and providing the information necessary for recycling to the molded product, recycling becomes easier. Even if recycling is carried out again, the QR code provided on the molded product ensures that the product can be recycled. In cases where a mold is not used, such as vacuum molding, it is not possible to engrave the molded product, so for example, the QR code can be silk-screened or a sticker with a QR code printed on it can be affixed. Of course, information such as the ink used for silk-screen printing and the material of the sticker are also written in the QR code.

[0261] (Embodiment 14) In recent years, as interest in environmental issues has increased, interest in biomass plastics has also increased. In the fourteenth to twenty-eighth embodiments, specific means and methods for producing resin pellets used in processing resins containing environmentally degradable components that are biodegraded in nature by the power (action) of bacteria, photodegraded by ultraviolet light, or hydrolyzed by water, and that are mainly thermovisible and thermosetting, are shown, as well as details of extrusion molding, injection molding, and other necessary devices using the resin pellets, and means for preventing discoloration, burning, and the like.

[0262] (mixing device) In this invention, the device that mixes each material is called a "mixing device." Common examples of mixing devices include tumblers, Henschel mixers, and rocking mixers, but any device that is used for the purpose of mixing each material is acceptable. There are no restrictions on the means or structure. A concrete mixer can also be used. In this invention, mixing using a tumbler is called "tumbling." It is preferable to use a weight control device, weight control feeder, weight feeder, etc., such as a Backmelter (product name) shown in the embodiment described later (see Figures 45 and 46, reference numbers 187 and 188).

[0263] (Dust explosion) Environmentally degradable components and substances such as cellulose powder, paper powder, wheat flour, bran, and wood powder are flammable fine powders, so there is a risk of dust explosions. The air inside the mixing device is replaced with an inert gas, such as nitrogen gas, before each material is placed in the device and mixed. A specific explanation will be given using a tumbler. The air in the tumbler is replaced with nitrogen gas, and cellulose powder, thermoplastic resin, and other additives, if necessary, are placed in the device, and the tumbler is rotated to mix. The same is true for the Henschel mixer; the inside of the mixer is replaced with nitrogen gas beforehand, and then each material is added and mixed. Even during the mixing stage, nitrogen gas should continue to be added as necessary. The environmentally degradable component of the present invention may be used in one kind, but if necessary, several kinds may be mixed and used, which is expected to improve quality and provide economical benefits.

[0264] (Tumbler) It is common to mix the thermoplastic resin and the environmentally degradable component in a tumbler before pelletizing. This mixture naturally contains air. In particular, the environmentally degradable component is in powder form, so it is particularly prone to containing air. Naturally, air contains about 20% by volume (about 23% by weight). If the mixture is pelletized in this state using a kneader (including pressure kneaders), Banbury mixer, single-screw extruder, or multi-screw extruder, the oxygen will oxidize the environmentally degradable component or some of the components in the environmentally degradable component, such as lignin, and cause discoloration. To solve this problem, an inert gas is introduced into the tumbler to reduce the oxygen concentration. Lignin can be removed, for example, by washing with water and / or an organic solvent, by raising the temperature of the water and / or the organic solvent, by boiling in hot water, or by washing with steam. When washing with steam, the environmentally degradable components absorb water, making it possible to reduce their volume. When washing with water, the components also absorb water. By reducing the volume in this way, operations such as melting and kneading in a tumbler are made easier.

[0265] (Melting and kneading equipment) In the present invention, a device that heats, melts, and kneads the thermoplastic material among the mixed materials is called a "melt kneading device." Examples of such a device include a single-screw (one-screw) or multi-screw (e.g., two-screw) extruder, a heatable kneader, a heatable Banbury mixer, and a heatable roller. However, before being fed into the melt kneading device, there is a risk of dust explosion, so measures such as nitrogen gas replacement are required. For example, when melt kneading is performed using a twin-screw extruder, which may rotate in the same direction or in different directions, in addition to dust explosions, for example, when cellulose powder colored in a desired color, such as white (several types of environmentally degradable components may be mixed in), is mixed with a thermoplastic resin and melt kneaded, the environmentally degradable components will discolor or burn, and the desired color will not be obtained. If colored, the intended color will not be achieved. This is because when melt kneading a thermoplastic resin in an extruder heating tube, even if the resin used is PP, it is heated to nearly 200°C. At this temperature of 200°C, for example, if an environmentally degradable component is used, it will discolor to yellow or brown. In some cases, if the temperature of the melt kneading is increased, it will burn to black. This discoloration and burning problem is caused by oxygen in the air, and discoloration occurs in an atmosphere where oxygen is present. In inert gases such as nitrogen gas, carbon dioxide gas, and rare gases, discoloration is minimal. Or there is no discoloration at all.

[0266] As a means for solving the problem of discoloration, the inventor replaces the inside of the hopper with nitrogen gas, for example, when using an extruder for pelletization, sheet molding, etc. Specifically, by replacing the inside of the hopper with nitrogen gas and injecting nitrogen gas into the vent part of the extruder, the nitrogen gas also enters the heating cylinder, preventing discoloration.

[0267] Even when the nitrogen-substituted mixture (mixture 001 in which the air in the gaps has been replaced with nitrogen gas) is melt-kneaded using a kneader, Banbury mixer, single-screw mixer, or multi-screw extruder, there is a risk of discoloration due to oxidation if oxygen gets in. Now, melt-kneading using a single-screw or multi-screw extruder will be explained. It is preferable to replace the air in the hopper of the extruder with nitrogen gas before putting the mixture into the hopper. The mixture to be melt-kneaded and pelletized (tumbled and nitrogen-substituted) is placed in the hopper, and nitrogen gas is continuously introduced into the hopper. In the present invention, this is called sealing the hopper with nitrogen gas. Nitrogen gas should be injected into the hopper and sealed so that it comes out from the bottom of the hopper, just before the heating cylinder, inside the hopper, and preferably from the center of the material, as shown in Figures 45 and 46. Nitrogen gas (reference numbers 187 and 188) below the hopper is sent from the hopper to the heating cylinder together with the mixture 001.

[0268] (Discoloration / burning) Environmentally degradable components and thermoplastic resins do not cause any problems at room temperature, but when they are heated to high temperatures, for example to nearly 200°C, and come into contact with air, they are oxidized by the oxygen in the air and turn yellow or brown. If the oxidation progresses further, they become burnt. In this invention, discoloration and burning are collectively referred to as "discoloration, etc." or "discoloration / burnt."

[0269] (molding equipment) The term "molding equipment" refers to an extruder, a sheet extruder, a profile extruder, an injection molding machine, a block molding machine, a casting machine, a calendar molding machine, a blow molding machine, etc. Products processed using a molding equipment are called "molded products, molded products, molded products." In the present invention, pellets of the raw material are also included in the molded products.

[0270] (cooling device) "Cooling equipment" refers to conveyors for air-cooling the thermoplastic resin strands coming out of the extruder, water tanks for water-cooling, temperature regulators that control the temperature of the molding machine, chillers, etc. In the case of sheet molding, it also refers to conveyors, water tanks, etc. that cool the sheet.

[0271] (Molding equipment) "Molding equipment" is a general term for extruder dies, molds for casting processing, molds for injection molding processing, etc.

[0272] (Molding method) The "molding method" referred to in the present invention refers to extrusion molding, profile extrusion molding, cast molding, injection molding, block molding, calendar molding, and the like, which are used to produce strands or sheets. In particular, injection molding includes, in addition to general molding methods (general molding methods, normal molding methods), injection foam molding using a chemical foaming agent whose properties are solid or liquid (; in the form of a slurry), injection foam molding using a physical foaming agent whose properties are solid, liquid, or gas (also simply referred to as "foam molding, or foam molding method"), extrusion molding, profile extrusion molding, cast molding, block molding, calendar molding, and the like, which use the above-mentioned foaming agents. Simpress (product name), AGI (product name), Air Mold (product name), and its applied technology RFM, H 2 Injection blow molding methods such as the M molding method (which are also referred to simply as "blow molding" or "blow molding methods" in the present invention), and injection pressure molding (which is also referred to simply as "pressure molding" or "pressure molding method") in which a gas having a pressure equal to or higher than atmospheric pressure is introduced into the gap between the molten resin and the mold and pressure is applied by the pressure of that gas can also be carried out using the resin containing the environmentally degradable component of the present invention.

[0273] (inert gas) The term "inert gas" refers to a gas that contains an environmentally decomposable component and does not oxidize a molding material containing a thermoplastic resin when the actual temperature of the molding material is 380°C. Examples of such gases include nitrogen gas, carbon monoxide, carbon dioxide gas, hydrogen gas, gas obtained by vaporizing an organic solvent, and rare gases such as helium and neon. These gases are used alone or mixed together to form a composite gas. Particularly useful gases in the present invention are nitrogen gas and carbon dioxide gas. In particular, nitrogen gas is used frequently in the present invention because it can be obtained in large quantities at low cost using a separation device such as a separation membrane or PSA. In addition, oxidation in the present invention refers to bonding with oxygen and decomposition by oxygen, as well as the loss of electrons by the target substance.

[0274] (Gas replacement) "Gas replacement" refers to the process of reducing the pressure and degassing the oxygen-containing air that has entered the device and / or the gaps in the materials, and then introducing an inert gas, such as nitrogen gas or carbon dioxide gas, under reduced pressure, and then raising the pressure back up to atmospheric pressure. Instead of reducing the pressure, it is also possible to introduce an inert gas and then pressurize. For example, an inert gas with a pressure equal to or higher than atmospheric pressure is introduced and replaced with the air. This method can be done once, but repeating it several times will ensure sufficient replacement. The air in the hopper of the extruder or injection molding machine, and the air in the gaps between the materials, can be reduced in pressure, pressurized with the gas to be replaced, reduced in pressure, and pressurized with the gas to be replaced, repeatedly. Since equipment optimal for this method, such as a back melter (Back Melter) (product name), is available, gas replacement can be easily performed. It is also possible to simply perform a vacuum (which actually means to reduce the pressure) using Haruna Co., Ltd.'s Eco Mac (product name). The inert gas can be introduced again into the vacuum device. In this invention, devices with functions such as a back melter and Eco Mac are collectively referred to as "back melters". The pressure may be increased to above atmospheric pressure without reducing the pressure in the back melter, returned to atmospheric pressure, and then increased to above atmospheric pressure again for replacement.

[0275] The mixture of environmentally degradable components and thermoplastic resin mixed in a tumbler is placed in a closed container, and a vacuum is drawn using a vacuum pump or the like. When inert nitrogen gas is poured into the reduced pressure, the air (especially oxygen) in the tumbled material is replaced by nitrogen gas. This process of replacing air with nitrogen gas can replace as much oxygen as possible with nitrogen gas even in one go, but if further replacement with nitrogen gas is desired, it is preferable to carry out the process multiple times.

[0276] (Gas sealing) "Gas sealing" means, for example, that after air has been expelled and replaced with inert nitrogen gas, in order to prevent air from re-entering, nitrogen gas is continuously or intermittently pumped into an apparatus, such as the hopper or feed screw (subscrew) of an extruder, to create an atmosphere of only inert gas inside the apparatus.

[0277] {Gas Under Pressure (GCP), GCP method, outer GCP} "Outer GCP" is a method for obtaining a smooth foamed product with a clean surface without swirl marks in foam molding. Normally, air pressurized to a pressure higher than atmospheric pressure is used, but as mentioned above, discoloration and burning are significant when environmentally degradable components are used. To solve this problem, gases such as nitrogen gas or carbon dioxide gas are used for the GCP instead of air containing oxygen.

[0278] In the so-called GCP method, in which a mold is sealed with an O-ring for PL, a load-type O-ring for ejector pins, or an ejector box, and then pressurized with a gas (usually air) to above atmospheric pressure before filling it with foamable resin, and the gas inside the mold is evacuated during or after filling with the foamable resin to obtain a foam-molded product with a clean, smooth surface and an internal foam layer, if the gas used is air, discoloration and burning will occur, but if the mold is pressurized in advance (this is called "pressurization", also known as "compressed air" or "pressurizing") and the gas used for pressurization is not air {air contains oxygen, which will cause discoloration and burning.} but inert nitrogen gas, discoloration and burning can be reduced. First, the inside of the sealed mold is pressurized with air, and then nitrogen gas with a higher pressure than the air is introduced into the cavity, and the initial air is expelled and replaced by the nitrogen gas pressure. In this case, the nitrogen gas is mainly used to pressurize the inside of the cavity, and other parts of the mold, such as the space at the bottom of the insert and the inside of the ejector box, are pressurized with inexpensive air, which is more economical than pressurizing the entire sealed injection mold with nitrogen gas. Sometimes, a vacuum is used to remove the initial air, and then nitrogen gas is used again to pressurize the chamber. It is also possible to use nitrogen gas to pressurize the chamber from the beginning. GCP is explained in PCT / JP2016 / 86380, PCT / JP2015 / 062611, and PCT / JP2020 / 015536, and the contents of the above-mentioned documents are used in the foam molding, GCP, blow molding, and pressure molding of the present invention.

[0279] (Fluid support) Using carbon dioxide gas in the GCP not only prevents discoloration and burning, but also has the effect of improving the fluidity of the molten resin by entering the leading edge of the flow of the molten resin filled in the cavity. Carbon dioxide gas has a higher affinity with molten resin than nitrogen gas, and when carbon dioxide gas dissolves in the resin, the fluidity improves. A mixture of nitrogen gas and carbon dioxide gas can also be used.

[0280] Even when a sealed mold is not used, the mold is closed and nitrogen gas with a pressure equal to or greater than atmospheric pressure is introduced into the cavity before filling with molten resin (which can be either foamable or non-foamable resin). The air in the cavity is initially replaced with nitrogen gas, and then the molten resin is filled in the process. In this process, the injection of nitrogen gas can be stopped before the molten resin is filled, or the injection of nitrogen gas can be continued once filling has begun until filling is completed.

[0281] (Flow support and dispersion) A fluidity improver is used to increase the fluidity of molten resin, but in molding equipment, extruders and injection molding machines, a hole is made in the heating barrel, and liquid that vaporizes at the temperature inside the heating barrel, such as water, alcohols, a mixture of water and alcohol, or other organic solvents, is poured in through the hole, and the fluidity of the molten resin can be significantly improved. Naturally, if the fluidity can be increased, the dispersibility of the environmentally degradable components in the thermoplastic resin can also be increased. An anionic, cationic, or nonionic surfactant can be added to this liquid (used in combination). Commercially available dispersants can also be used.

[0282] In addition to the liquids mentioned above, gases such as nitrogen gas and carbon dioxide gas can be added to the molten resin to increase its fluidity. Carbon dioxide gas has a higher affinity (ease of mixing) with molten resin than nitrogen gas, so if a gas is used, carbon dioxide gas is the best. Solid blowing agents, such as hydrogen carbonates represented by sodium bicarbonate, chemical blowing agents such as azo compounds represented by ADCA, and nitrosated compounds represented by DPT, as well as physical blowing agents such as hollow air balloons, have the effect of increasing the fluidity of the molten resin in the heating barrel.

[0283] To increase the binding strength between the environmentally degradable component and the thermoplastic resin, if the thermoplastic resin is PP, an emulsion (solvent-based is also acceptable) containing maleic acid-modified PP, which has a high binding strength with PP resin, is placed in the heating cylinder in the same manner as in the case of the liquid described above to increase the binding strength (binding force) between the environmentally degradable component and the PP resin. If the thermoplastic resin is a styrene-based resin such as ABS, a solution of styrene-modified acrylic resin in emulsion or a solution of styrene-modified acrylic resin dissolved in a solvent is used. If the thermoplastic resin is polyamide, a solution or emulsion of methoxymethylated polyamide is used in the same manner and placed in the heating cylinder. Of course, maleic acid-modified PP, styrene-modified acrylic resin, methoxymethylated polyamide solid (powder, etc.), and polyvinyl alcohol may be mixed together. In this case, if the maleic acid-modified PP or the like is in a solid state, they are mixed in the tumbler (tumbling) stage and then fed into the extruder hopper, etc.

[0284] Liquefied carbon dioxide gas is injected into the barrel and vaporized at the temperature of the heating tube, and can be used as a flow improver as carbon dioxide gas in the heating tube. Solid carbon dioxide gas (dry ice) is pelletized, and a device with a mechanism like a back melter is installed in an extruder, injection molding machine, or other molding device, and a mixture of dry ice, environmentally degradable components, and thermoplastic resin is placed in the heating tube and melted. When melted, the dry ice sublimes and becomes carbon dioxide gas, which dissolves in the molten resin. As a result, the molten resin in the heating tube has improved flowability because carbon dioxide gas has been dissolved in it. Dry ice can be used as a flow improver. Another method is to improve the fluidity of substances that impart foaming properties to the molten resin in the heating barrel, such as hydrogen carbonates (salts of alkali metals such as Li, Na, and K), azo compounds such as ADCA, and nitrosated compounds such as DPT. Fluidity can also be improved by introducing gases such as Musel, Amotec, and Sofit into the heating barrel to impart foaming properties to the molten resin in the heating barrel. Of course, there are also fluidity improvers as another method.

[0285] If liquid is added to the molten resin in the heating cylinder and the fluidity increases, the GCP pressure can be lowered. Or, even without a GCP (atmospheric pressure), foamed molded products without swirl marks can be obtained, and molded products that eliminate foam cells by applying resin holding pressure and are standard molded products can be obtained. In this case, for example, if the resin is PP, the liquid is not ethanol, but alcohols with a large number of carbons such as propanol, butanol, and hexanol, which have high solubility in the molten resin, so even if the GCP pressure is low or the same as atmospheric pressure, foamed molded products and standard molded products without swirl marks can be obtained. This action and effect has been confirmed not only with alcohols but also with alkanes.

[0286] (Embodiment 15) (Pellet manufacturing) The particle size of the environmentally degradable component used in the fifteenth embodiment is not particularly important. It may be large or small. In some cases, large and small particles may be mixed together. The average particle size of the cellulose powder (KC Flock W-100GK, W-50GK, W-400G) manufactured by Nippon Paper Industries Co., Ltd. used in the examples of the present invention is sufficient if it is 200 μm or less, and when uniformity (uniform dispersion) is required to be improved in dispersibility, 20 μm or more and less than 50 μm are used. The cellulose powder KC Flock manufactured by Nippon Paper Industries Co., Ltd. is originally a white powder like shoji paper. A mixture (referred to as "Mixture 001" in the present invention) of 51 wt.% of this white powder (cellulose powder) and 49 wt.% of natural colored PP resin {Sumitomo Noblen HX101A (product name)} was heated and melt-kneaded with a kneader {pressure kneader manufactured by Toshin Co., Ltd.} using an electric rod heater for heating. The melting temperature was adjusted to below 200°C, but the product that was melted and kneaded with the cellulose powder and PP resin turned brown (originally, both the cellulose powder and the PP resin pellets were white.) It was speculated that the cause of this was the cellulose powder being oxidized by the air (oxidized by oxygen in the air), causing the discoloration.

[0287] To confirm whether the discoloration was caused by oxygen in the air, the heating section of the kneader was enclosed in a vinyl bag and inert nitrogen gas was poured inside {Nitrogen gas was continuously poured in while melting and kneading in the kneader, replacing the air and sealing the resin melting environment (the atmosphere during melting and kneading) with nitrogen gas. ) Similarly, when it was melted and heated at 200℃, there was almost no discoloration and it was white, compared to the one melted and kneaded in air. This made it clear that the discoloration was caused by oxygen in the air. Although slight discoloration was observed, it was assumed that this was due to air getting into the gaps between the cellulose powder and PP pellets.

[0288] When the melt-kneaded lump of PP resin containing the cellulose powder was taken out of the nitrogen gas atmosphere into the air, the surface temperature was close to 200°C, the same as during melt-kneading, and the surface turned brown due to the oxygen in the air. This experiment confirmed that cellulose powder is easily oxidized and discolored, but this discoloration problem can be solved by replacing the air with an inert gas such as nitrogen gas.

[0289] Conventional resin (e.g. PP resin) pellets are made by cooling strands in water and then cutting them into pellets. However, since the environmentally degradable components have high water absorption, cooling in water is not preferred and air cooling is preferable. The molten mass of PP resin containing cellulose powder that had been melt-kneaded earlier, before it had completely cooled and solidified, was extruded using a plunger-type extruder and cooled in air on a stainless steel mesh conveyor (as cellulose has high water absorption), and strands were extruded and cut using a pelletizer to obtain PP resin pellets containing cellulose powder. However, at the stage of extruding and forming strands using the plunger, the process was carried out in air (strand cutting, air cooling and solidification), so the surface of the strands was oxidized and turned brown.

[0290] It was confirmed that discoloration can be prevented by replacing the air with nitrogen gas, as in the case of the kneader. Specifically, the conveyor is enclosed in a tunnel structure, and nitrogen gas is poured inside to replace the air with nitrogen gas. The strands extruded from the die are cooled by blowing nitrogen gas onto them. In this way, by replacing the air with nitrogen gas at the melt-kneading stage and the stage of pulling the strands and pelletizing them, oxidation of the cellulose powder can be prevented, and white pellets without discoloration can be obtained. Although only cellulose is used in the above embodiment, cellulose powder and paper powder (either from a paper mill or paper collected from the market that has been pulverized) can also be used. These can also be mixed together.

[0291] (Embodiment 16) (Method to prevent oxidation: nitrogen gas sealing) From the third embodiment, it was confirmed that the discoloration of the cellulose powder (due to oxidation) is caused by oxygen in the air. However, the pressurized heated kneader is a batch-type production (manufacturing) method, and therefore the productivity is low. To obtain pellets, continuous production using a single-screw or multi-screw extruder and a pelletizer reduces production costs and is more economical. The 16th embodiment shows a method for obtaining discolored pellets without oxidation using an extruder. Mixture 001 is placed in the hopper of an extruder, and the air in the hopper is replaced with inert nitrogen gas. In practice, nitrogen gas can be continuously introduced into the lower part of the hopper (preferably the part of the pipe connected to the heating cylinder) using a thin hose. Nitrogen gas can be purchased from a commercially available cylinder, but in this case, nitrogen gas cylinders are expensive and not economical. The inventor used nitrogen gas separated from the air using PSA (Pressure Swing Adsorption) or a nitrogen gas separation membrane {hollow fiber (N2 separator) sold by UBE Co., Ltd.}.

[0292] As mentioned above, by replacing the air inside the hopper with nitrogen gas, the oxygen concentration will decrease, and discoloration due to oxidation will be avoided. To prevent further discoloration, for example, a high vacuum plasticizing device inside the heating cylinder (Buck Melter, Bacmelter (product name)) manufactured and sold by Meiki Seisakusho Co., Ltd. and Japan Steel Works Co., Ltd. as an attachment to molding machines is used. Mixture 001, whose hopper has been replaced with nitrogen, is placed in the heating cylinder, and before melt-kneading, a vacuum is drawn using the back melter to suck out the air that has entered the gaps between the cellulose powder and PP resin pellets. The mixture may be placed in the heating cylinder as is and melt-kneaded.

[0293] If necessary, after drawing a vacuum, nitrogen gas can be pumped into the back melter, and the air in the gaps will be replaced with nitrogen gas. To further increase the effect of replacing the nitrogen gas, use multiple back melters instead of one.

[0294] Mixture 001, whose air has been replaced with nitrogen gas, is fed into the extruder for melting and kneading, but in order to stabilize the amount fed into the extruder, small sub-screws (feed screws) are installed above the heating barrel, below the hopper, and between the heating barrel and the hopper. In this case, it is advisable to also replace the air inside the sub-screw with nitrogen gas. This is necessary and recommended to prevent discoloration.

[0295] The extruder may be a single screw (one screw) or a multi-screw (e.g., two-screw) extruder with strong (high) mixing ability. In the case of a multi-screw extruder, the rotation directions of the screws may be either synchronous or counter-rotating. In the case of an extruder, a vent is provided in the heating cylinder. This vent is also covered and nitrogen gas is poured inside to perform nitrogen gas sealing (meaning replacing air with inert nitrogen gas). After melting and kneading, the material is extruded through a die to form strands. It is cooled and solidified using a stainless steel mesh conveyor belt. As explained above when pellets were obtained using a kneader, during the cooling and solidification stage, in order to prevent discoloration due to oxidation on the strand surface, nitrogen gas replacement (replacement of air with inert nitrogen gas; replacement of oxygen in the air with nitrogen gas) is similarly performed to prevent discoloration on the strand surface due to oxidation when it comes out of the die. Once cooling and solidification is complete, the temperature drops and the material is pelletized (cold cut). By thus lowering the oxygen concentration in the air to approximately zero, white pellets can be obtained without discoloring the cellulose powder. By adding pigments and dyes during the pellet manufacturing process, pellets containing cellulosic powder in various colors can be obtained. Furthermore, PP does not oxidize at a melting temperature of 200°C. Therefore, it has been confirmed that PP does not discolor or burn at around 200°C.

[0296] When a dulmage screw is used for the extruder in order to enhance the kneading property, the kneading property is high, and therefore the environmentally degradable component is highly dispersible in the thermoplastic resin. If a vaporizable liquid is introduced into the molten resin in the heating barrel after melt-kneading by the means shown in Patent Publication (PCT / JP2015 / 062611), not for the purpose of foaming as in Patent Publication (PCT / JP2015 / 062611), but rather to lower the melt viscosity of the molten resin in the extruder heating barrel, the kneadability of the cellulose powder and the PP resin is improved, and dispersibility is improved. Since the purpose is not foaming, the amount of ethanol to be added is, for example, 1 part or more, preferably 3 parts or more, per 100 parts of the molten resin containing the environmentally decomposable component. The vaporizable liquid should be alcohols such as ethanol and propanol, water, or a mixture of water and alcohols. Methanol can be used, but is not recommended due to its toxicity. Its use is discontinued in this invention. If you add dyes to this liquid, you can color the pellets. Liquid injection is not limited to one place, but can be done in several places. You can also add a solution containing alcohol, dyes, or pigments. In order to increase the bonding strength between the cellulose powder and the olefin resin PP and to increase the strength of the final molded product, an emulsion-type solution of maleic acid-modified PP (model number DB-4010 (Arrowbase (product name)) sold by Yuichika Co., Ltd.) may be added to increase the bonding strength at the interface / boundary region between the cellulose and PP. Naturally, it is possible to make it even whiter by adding white inorganic substances such as titanium oxide, alumina, and magnesia. Use plasticizers, preservatives, anti-mold agents, dispersants, etc. as necessary. If these substances are solid, mix them in appropriate amounts with Mixture 001, for example. In the case of a solution using an organic solvent such as alcohol, the solution may be injected into the heating cylinder using the liquid injection device described above (Patent Publication PCTPCT / JP2015 / 062611) shown in Figs. 1, 4 to 19.

[0297] (Embodiment 17) (Injection molding processing) The following describes a method for preventing oxidation of cellulose powder when the cellulose powder-containing pellets 001 obtained in the third and fourth embodiments using the mixture 001 are injection molded. The means for this is nitrogen replacement and nitrogen sealing, as in the case of pellet 001, and discoloration and burning during injection molding can be prevented. First, the inside of the hopper of the injection molding machine is replaced with nitrogen gas. The replacement method is the same as the nitrogen replacement method in the hopper when pellet 001 was produced using an extruder in the above pellet production. The inside of the hopper is replaced with nitrogen, and then the pellets are plasticized in the heating cylinder of the injection molding machine. The injection molding machine of the fifth embodiment is equipped with the back melter described above, and the pellets 001 in the hopper have some of the air in the gaps between the pellets replaced with nitrogen gas, and then the pellets are sent into the back melter. The back melter is evacuated, and the pellets are sent into the heating cylinder, where they are melted, plasticized, and kneaded. After the back melter is evacuated, nitrogen gas may be introduced into the back melter again. Naturally, a single-stage back melter is sufficient, but if multiple stages are used in series, the nitrogen gas replacement rate can be further increased. In this way, the gaps between pellets 001 are replaced with nitrogen gas, so discoloration and burning caused by oxygen do not occur during the plasticization and melting / kneading stages.

[0298] The pellets 001 plasticized in the heating barrel of the injection molding machine are then filled into the mold, but since there is air in the cavity of the mold, actually the oxygen in the air, there is a risk of discoloration and burning in the resulting molded product. If the injection speed is increased, discoloration and burning will increase due to adiabatic compression. In order to solve this problem, the inside of the cavity is replaced with an inert gas, for example, nitrogen gas. A specific method for replacing the inside of the cavity with nitrogen gas will be described below. The mold used is provided with gas injection pins and gas pressurization pins shown in Fig. 52, Fig. 53, and Fig. 54 in the patent publication (PCT / JP2016 / 86380) on either the fixed side, the movable side, or the spool runner (multiple are possible). The mold is closed, and the valve (reference number 14) in Fig. 1 of the patent publication (PCT / JP2016 / 86380) is opened to blow nitrogen gas into the cavity. When the air in the cavity is replaced with nitrogen gas, the molten resin of the pellet 001 is injected (filled) into the cavity. When the cooling and solidification of the molten resin is completed, the mold is opened and the molded product is taken out, and a beautiful white injection molded product without discoloration or burning is obtained, which is injection molded using the pellet 001 produced using the mixture 001.

[0299] (Embodiment 18) Pellet 001 contains 51wt% cellulose powder, so its fluidity is significantly lower than that of 100% PP resin. Furthermore, the resin temperature during molding cannot be made very high because of concerns about discoloration and burning of the cellulose powder. Therefore, as an application of the foam molding method using liquid described in the patent publication (PCT / JP2015 / 062611) as a means to increase the fluidity of the molten resin, alcohols, water, and a mixture of alcohols and water are added to the molten resin in the heating cylinder to improve the fluidity of the molten resin. Since the amount added is not foam molding, an amount several times more than that of foam molding is added, the fluidity is increased, and the resin is injected into a cavity replaced with nitrogen gas, and then the liquid is squeezed out by applying a resin holding pressure. This is a means of using a foaming agent and applying a holding pressure to prevent foaming. Naturally, there is a risk of discoloration and burning, so the inside of the hopper and cavity are replaced with inert gas and sealed with inert gas.

[0300] We have previously shown the use of alcohol as a liquid to improve the flowability of thermoplastic resin (as a means of injecting it into the heating barrel), but the material is not limited to alcohol. The same flow support effect can also be achieved by using nitrogen gas or carbon dioxide gas pressurized to a level where it can be injected into the molten resin in the heating barrel (pressure higher than the back pressure of the molten resin in the heating barrel during plasticization and melting). In addition to liquids such as alcohols, and gases such as nitrogen gas and carbon dioxide gas, baking soda (sodium hydrogen carbonate, sodium bicarbonate, sodium acid carbonate), ADCA (azo dicarboxylic acid amide), DPT (di-nitroso pentamethylene tetramine), and other medium-sized air balloons such as Advancel (trade name) and Expancel (trade name) can also be expected to have a similar fluidity support effect.

[0301] (Foam molding) Although the action and effect of flow support using a liquid has been explained above, it is of course possible to carry out foam molding using pellets 001. In the sixth embodiment, alcohols are used as a flow improver, but foam molding is possible if the amount added is reduced and an appropriate amount is used, and alcohols are also used as a foaming agent. The cellulose powder in the pellet 001 acts as a foam nucleating agent, and talc, metal oxides, inorganic fillers, etc., which act as nucleating agents for the purpose of foaming, may be added as necessary.

[0302] {Gas Counter Pressure (GCP), mainly outer GCP} Naturally, the Gas Canter Pressure (GCP) method described in the patent publication (PCT / JP2016 / 86380) and the literature {S&T Publishing Co., Ltd. October 20, 2022, 1st Edition, 1st Printing "Preparation for Mass Production of Foam Molding, Blow Molding, and Compressed Air Molding, and Explanation of Specific Means for Reducing Environmental Impact" by Yasutaka Suzuki and Minoru Shinbo} can be used to reduce floating on the surface of cellulose powder. By increasing the GCP pressure (pressurization inside the mold) and increasing the mold temperature, the floating of cellulose powder due to the effect of GCP can be further reduced. In GCPs using general resins such as ABS and PP, the gas used to pre-pressurize the inside of the mold is air, but air can cause problems with discoloration and burning, so inert nitrogen gas is sometimes used instead. When carbon dioxide gas is used, it dissolves into the molten resin from the front of the flow, improving the fluidity of the molten resin and reducing (holding down) the floating of the cellulose powder. Naturally, in the case of this foam molding, as explained in the fourth embodiment (which is extrusion molding, but injection molding is roughly the same) and the fifth embodiment, it is necessary to carry out nitrogen replacement in the hopper or using a device such as a back melter.

[0303] (Embodiment 19) (Extrusion molding = sheet extrusion molding) When using pellets 001 for extrusion molding to produce sheets, the inside of the hopper is sealed with nitrogen and replaced with nitrogen, as in the case of the injection molding, and if a feed screw is provided on the extruder heating barrel, the air in the feed screw is also replaced with nitrogen to prevent discoloration and burning due to oxidation, before putting the pellets into the heating barrel, plasticizing them, and extruding the sheets. This is the same for both injection molding machines and extrusion molding machines, but as long as oxygen does not enter the heating barrel, there is no need to worry about discoloration or burning even if the temperature is raised slightly.

[0304] However, when the sheet comes out of the extruder die, it has not yet cooled and solidified, and is still at a high temperature, so when it comes into contact with air, the surface will naturally oxidize and discolor. In some cases, burning may occur. The sheet must be in a nitrogen gas atmosphere until the surface has cooled and solidified completely, and the surface temperature has dropped to a point where it no longer oxidizes and discolors. Once cooling and solidification is complete, the sheet is cut to the desired size and used for pressure forming or vacuum forming.

[0305] In both the case of the extrusion molding for producing the sheet of the 19th embodiment and the case of the previous 18th embodiment, if a vent is provided in the heating barrel, air may enter the heating barrel through the vent and be oxidized, resulting in discoloration and burning. Therefore, nitrogen gas is introduced through that part (the vent section, vent opening, etc.) to prevent oxidation of the molten resin in the heating barrel. Another port is provided to add the environmentally degradable component in a slurry form (described later) to the heated and melted thermoplastic resin and knead it in. During the heating, melting and kneading stage, the water, organic solvent, etc. used in producing the slurry are sucked in through yet another vent port and released to the outside of the heating cylinder. The slurry is produced by adding water and / or an organic solvent such as alcohol to the environmentally degradable components and using a Henschel mixer, etc. For the produced slurry, in the case of single-screw or multi-screw extrusion molding, if the thermoplastic resin is an olefin resin such as PP, a maleic acid-modified PP solution (including water-based) is used, and if the thermoplastic resin is a styrene-based resin such as ABS or HIPS, a styrene-modified acrylic resin solution (including water-based) is used. The slurry is melted and kneaded using a single-screw or multi-screw extruder. When producing pellets, a constant amount of the slurry is continuously injected into the molten resin in the heating barrel using a plunger pump or the like, and melted and kneaded. In the case of injection molding, a certain amount of slurry is injected into the molten resin in the heating barrel of the injection molding machine from the start to the end of metering. This is called volume control. In the case of injection molding machines, the liquid injection device shown in the figure (photo 17 on page 36) in the literature {S$T Publishing Co., Ltd. October 20, 2022, 1st edition, 1st printing "Preparation for mass production of foam molding, blow molding, and compressed air molding, and explanation of specific measures to reduce environmental impact" by Yasutoshi Suzuki and Minoru Shinbo} can be used. Note that Figure 32 and photo 24 on page 66 of this book show the gas and GCP device.

[0306] (Embodiment 20) In the previous embodiment, PP, an olefin resin, was used as the resin (for example, mixture 001, pellet 001), but in the present invention, any resin that exhibits thermoplasticity can be used (is usable). PE can be added to lower the melting temperature of PP, for example, to create a mixed resin (polymer alloy, polymer blend) with PP:PE=50:50. It can also be implemented with only PE (PE alone). Since the PP was in the form of pellets, it was mixed with cellulose powder and pelletized to obtain pellet 001. However, since ABS is commercially available in powder form, the inventor mixed cellulose powder and ABS powder using a tumbler, Henschel mixer, etc. to obtain ABS-containing cellulose powder, and instead of pelletizing it, the powder mixture may be placed in a hopper as is and injection molded as is without pelletizing it. Of course, foam molding using alcohols and GCP are also possible. Other than ABS, ester resins such as PET, vinyl chloride, and polystyrene can also be used. Biodegradable plastics such as polylactic acid can also be used. Polymer alloys and polymer blends of these resins are also acceptable.

[0307] Although alcohol and other liquids have been exemplified as a means of increasing the fluidity of resin, liquefied carbon dioxide gas can also be used. If the back melter shown above is slightly modified and solid carbon dioxide gas (dry ice) is mixed into it and placed in the heating cylinder, the dry ice will sublimate at the temperature of the heating cylinder and become a foaming gas. By increasing the amount added, it can also be used as a fluidity improver or dispersant.

[0308] In the fourteenth to twenty embodiments of the present invention, the means for carrying out the invention are shown using cellulose powder, but the present invention is not limited to cellulose powder. Environmentally degradable components other than the cellulose powder shown in the present invention are also easily oxidized by oxygen and discolored or burned, so when using these substances, sealing with inert nitrogen gas or replacing with nitrogen gas should be performed.

[0309] (Embodiment 21) (Supported by maleic acid-modified PP, etc.) When the bonding strength between PP and an environmentally degradable component such as cellulose powder is low, a substance having a strong bonding strength with PP, such as maleic acid-modified PP or a halogenated polyolefin such as chlorinated PP or chlorinated PE, is used, for example, on the surface of the environmentally degradable component (e.g., cellulose powder, paper powder, etc.).

[0310] The first step of the implementation will be described below. When the environmentally degradable component is in powder form, in order to eliminate the risk of dust explosion, the atmosphere inside a Henschel mixer is replaced with an inert gas such as nitrogen gas beforehand, and the environmentally degradable component is then placed in the mixer, followed by maleic acid-modified PP (whose properties are emulsion type where maleic acid-modified PP is emulsified, or solvent type where a solvent is dissolved), and the like, and then the environmentally degradable component and maleic acid-modified PP are mixed together by stirring. The obtained mass of the environmentally degradable component containing the maleic acid-modified PP, etc. is crushed to a particle size (size) that can be melt-kneaded with PP resin, mixed with PP, and pelletized or formed into sheets.

[0311] In the case of styrene-based resins such as AS, ABS, PS, and HIPS, instead of PP, styrene-modified acrylic resin, acrylic resin, acid-modified acrylic resin, etc. are used in place of maleic acid-modified PP. As mentioned above, these are available in both emulsion and solvent types, so either can be used.

[0312] Poval (polyvinyl alcohol) dissolved in water or solvent can also increase the binding strength between the environmentally degradable component and the binder resin PP, ABS, HIPS, etc. The method of use (implementation) is the same as that of the maleic acid modified PP solution and styrene modified acrylic resin solution shown above.

[0313] A solution of maleic acid-modified PP or styrene-modified acrylic resin is injected into the heating cylinder and mixed with environmentally degradable components, PP, ABS and other binder resins at the melt-kneading stage. The water in the solution (water in the case of an emulsion) and the organic solvent in solvent-based products also act as flow improvers. In this case, other additives such as pigments and dyes can be injected at the same time. To impart flame retardancy to the resin, the flame retardant can be injected as a liquid using a solvent, water, etc.

[0314] When maleic acid modified PP or styrene modified acrylic resin is solid, the environmentally degradable components and binder resin are mixed in an explosion-proof tumbler (replaced with inert gas, sealed using inert gas), and then pelletized using an extruder, sheet (extrusion) molded, or directly injected into the hopper of an injection molding machine. Naturally, in this case, it is also possible to use alcohol or other fluidity improvers in combination, and these liquids are inje...

Claims

1. In the process of feeding a molding material mainly composed of a thermoplastic resin into a molding machine heating barrel and melt-kneading (including plasticizing and weighing) the molding material, In the stage of melt-kneading the molding material, liquid is poured into the molding resin in the heating cylinder, The liquid evaporates into steam at the temperature of the heating barrel and the temperature of the molten resin. the vapor of the liquid is pressurized and dissolved and / or finely dispersed by a physical force such as screw rotation to increase the fluidity of the molten resin; and filling a cavity with the molten resin having improved fluidity.

2. In the method according to claim 1, a resin dwell pressure is applied to the molten resin filled in the cavity by using a molding machine screw during and after the filling of the molten resin, and increasing the density of the molten resin filled in the cavity.

3. In claim 1 or / and claim 2, a gas having a pressure equal to or greater than atmospheric pressure is injected into the molten resin filled in the cavity through a nozzle, a spool runner, or / and directly into the molten resin filled in the cavity, and increasing the density of the resin by applying pressure to the molten resin from inside the molded article using the pressure of the gas.

4. In claim 1 or / and claim 2, a gas having a pressure greater than atmospheric pressure is introduced outside the molten resin filled in the cavity (in the gap between the resin and the mold, outside, on the outside), The method for producing a resin molded product comprises the steps of: applying pressure to the molten resin from outside the molded product using the pressure of the gas to enhance transferability to the mold; and increasing the density of the resin.

5. In the above-mentioned claim 1 or / and claim 4, a sealed mold is used, and the inside of the mold is pressurized with a gas that has been previously pressurized to a pressure equal to or higher than atmospheric pressure, 5. The method for producing a molded product according to claim 1, wherein the molded product is filled with a molten resin whose fluidity has been increased by a liquid.

6. 4. The method for producing a hollow molded product according to claim 3, wherein a seal mold is used, and the mold cavity is pressurized to atmospheric pressure or higher beforehand, and filled with resin whose fluidity has been increased by using a liquid.

7. 5. The method for producing a pressure-molded product according to claim 4, wherein a seal mold is used, and the mold cavity is pressurized to atmospheric pressure or higher beforehand, and the resin having its fluidity increased by using a liquid is filled into the mold cavity.

8. The fluidity of the molten resin in the heating cylinder is increased by adding liquid, and if necessary, gas, to the heating cylinder that has been heated and melted.

9. A step of injecting a liquid to reduce the melt viscosity of the molten resin in the heating barrel and improve the fluidity of the molten resin; and injecting a gas through a separately provided injection port into the molten resin whose viscosity has been reduced and whose fluidity has been improved by the liquid. The melt kneading screw used in the present invention is a melt kneading screw which injects liquid and then gas into resin and has a backflow prevention ring provided behind the liquid injection port provided in the heating barrel.

10. The thermoplastic resin used in any one of claims 1 to 9 is a molding material for molding processing, the main component of which is a thermoplastic resin blended with inorganic and / or organic resin additives.

11. A resin molded product molded using the processing method and molding material according to any one of claims 1 to 9.

12. A mold device used when performing molding using the processing method and molding material according to any one of claims 1 to 9.

13. A molding apparatus used when performing molding using the processing method and molding material according to any one of claims 1 to 9.

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