Manufacturing method for foamed molded products

Abstract

The present invention provides a method for manufacturing a molded article having a foamed layer within it, and includes a foaming agent, apparatus, mold, molding machine, means for increasing the foaming ratio, and means for improving paintability, all used in the production of foamed resins. [Solution] When the carrier resin used in the production of the foaming agent master batch is manufactured from a resin that is compatible (solubilable) with the intended compound, a molded product with a good appearance can be obtained. When inorganic sodium bicarbonate is used as the foaming agent, sodium carbonate in the foaming residue (the residue remaining in the molded product after the foaming agent decomposes and generates foaming gas) reduces the adhesion of the coating film. Therefore, if the sodium carbonate is removed by acid washing beforehand, the paint suitability will be satisfactory. When performing GCP, the thickness of the surface skin layer changes depending on the mold surface temperature. Generally, the use of heated steam is a common method for raising the mold temperature, but in this invention, a method of heating magnetic fluid (liquid) by high-frequency induction is used to provide an inexpensive, highly efficient, and safe mold temperature increase.

Description

Technical Field

[0001] The present invention relates to a foaming agent used for obtaining foam-molded (molded) articles, a method for producing foam-molded articles, a coating method for foam-molded articles, means for producing foam-molded articles serving as base materials, and an apparatus for producing the same.

Background Art

[0002] Patent Document 1 describes a foam molding method, which comprises performing a short shot of a molding material consisting of a resin (plastic) and a foaming agent into a mold with an insert arranged therein, leaving an unfilled portion, and filling the unfilled portion with an expansion force generated by foaming of the foaming agent. The resin consists of a base resin and a low-molecular-weight resin that is of the same type as the base resin and has a lower molecular weight than the base resin. Patent Document 2 describes a gas counter pressure (abbreviation: GCP) method which is a means for suppressing swirl marks (foamed stripe patterns, abbreviation: SM) generated on the surface during foam molding, and a mold structure therefor, and describes the use of a U-shaped O-ring. Document 3 describes a pretreatment for bumpers of vehicle parts, but there is no description that limits the scope to articles (products, molded articles, etc.) that use GCP as a means for smoothing the surface of a foam-molded article using baking soda or a foaming agent containing baking soda in foam molding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

[0004] Coating Engineering: Vol.27 No.11 (1992) "On Low-pollution Surface Treatment of Plastic Bumpers" by Yuichi Yoshida; pages 505(21) to 511(27)

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] The object of this invention is to obtain a foam molding with a smooth surface, and to apply a coating to the foam molding product and ensure sufficient adhesion of the coating film. Means for solving the problem

[0006] (Configuration of Claim 1) The first invention according to claim 1 involves pressurizing the inside of a sealing mold to 0.6 MPa or higher, maintaining that state, and then starting to vent the pressurized air when the foamed resin has filled 90% or more of the molding space.

[0007] (Effect of Claim 1) The first invention according to claim 1 is that, when a GCP device is connected to L1, L2, and L3 respectively, as shown in Figure 38, if L1 or L3 (generally L1, which has a larger volume of compressed air, is exhausted first) and then L2, discoloration and burning due to adiabatic compression can be eliminated. If one GCP device is connected to L1, L2, and L3, exhaust will occur when the volume reaches 90% all at once.

[0008] (Effects of Claim 1) The first invention according to claim 1 allows for the production of foamed molded products that are free from short molds, discoloration, and burning caused by compressed air, when the foamed resin is filled into the molding space to 90% by volume or more.

[0009] (Explanation of Claim 1) Compared to conventional molding, GCP has a greater amount of gas in the molding space due to its pressure. While this compressed air is effective in suppressing surface foaming during foam molding, it can interfere with the filling of the foaming resin into the molding space, causing short molds, discoloration, and burning. The force of the resin filling moves the gas to spaces outside the molding space. Even if the molding space is not completely filled with foaming resin, or if the gas is vented at an early stage, depending on the shape of the product, surface foaming and swirl marks will not occur.

[0010] (Effects of Claim 2) The second invention according to claim 2 involves pressurizing the inside of the sealing mold and starting to release the pressurized air from the time the foamed resin is filled into the molding space.

[0011] (Effect of Claim 2) The second invention according to claim 2 is that since the exhaust of compressed air is started after the molding space is completely filled with foamed resin, swirl marks are eliminated and a foamed molded product with a smooth surface and a beautiful appearance can be obtained.

[0012] (Effects of Claim 2) The second invention according to claim 2 is such that exhaust is initiated after the molding space is completely filled with foamed resin, thus suppressing swirl marks on the surface. The timing of exhaust is either during the filling of the molding space with foamed resin or after the molding space is completely filled. Since the timing of exhaust is changed according to the shape of the molded product, it is possible to manufacture foamed molded products that are free from swirl marks, short molds, discoloration, and burning.

[0013] (Explanation of Claim 2) As shown in Figure 38, if GCP devices are connected to L1, L2, and L3 respectively, exhaust either L1 or L3 first (generally L1, which has a larger volume of compressed air, is exhausted first), followed by L2. The timing of the exhaust is staggered. The compressed air in the molding space is pushed to other locations (L1, L3, GCP device, and GCP hoses) by the force of resin filling, so the pressure on the leading edge of the foamed resin being filled does not become very high. As a result, foamed molded products without swirl marks and without short molds are obtained. In this invention, the transfer of compressed air in the molding space to other locations by the force of filling is called "transfer".

[0014] (Configuration of Claim 3) The third invention according to claim 3 is a means of increasing the foaming ratio of a foamed molded product, by retracting the mold at the same time as the start of exhaust of the GCP, thereby performing mold back and / or core back.

[0015] (Effect of claim 3) The third invention according to claim 3, after foam-molding with a smooth surface using GCP, performs mold back and / or core back when the internal cooling and solidification have not yet been completed, whereby a molded article having a smooth swirl-mark-free surface and a high expansion ratio can be produced. Further, by performing mold back and / or core back simultaneously with exhaust of GCP, rain drops can also be eliminated.

[0016] (Effect of Claim 3) The third invention according to claim 3 can obtain a foam-molded article having a high expansion ratio, and thus provides economic effects such as reduction in material costs.

[0017] (Description of Claim 3) The third invention according to claim 3 performs mold back and / or core back simultaneously with the start of exhaust of GCP, whereby a gas vent is formed by opening a parting line in addition to a GCP exhaust valve, and pressurized gas is exhausted at a stroke. Thus, a foam-molded article having a beautiful appearance free of rain drops caused by pressurized gas can be obtained.

[0018] (Configuration of Claim 4) Mold back and / or core back is performed on the stationary side of the mold.

[0019] (Action of Claim 4) It is also possible to perform mold back and / or core back on the stationary side of the mold, and as in the case where the mold back / core back is performed on the movable side, a foam-molded article having a high expansion ratio can be obtained.

[0020] (Effect of Claim 4) Due to the mold structure (for example, a three-plate mold having a stripper plate), performing mold back and / or core back on the stationary side can simplify the mold mechanism compared to performing the same on other sides.

[0021] (Description of Claim 4) A mechanism such as a spring is placed in the mold, and when the die plate is retracted and the mold is opened by the molding machine (in this invention, "molding machine" mainly includes injection molding machines and machines that perform processing very similar to injection molding machines), the fixed side of the mold is also retracted.

[0022] (Configuration of Claim 5) The fifth invention according to claim 5 provides a mechanism in the mold and the molding machine that, when the molding machine die plate is retracted and the mold is opened, the movable side and the fixed side of the mold retract, thereby performing mold back and / or core back.

[0023] (Effect of Claim 5) The fifth invention according to claim 5 involves molding back and / or core back the movable side and the fixed side, thereby increasing the foaming ratio.

[0024] (Effects of Claim 5) The fifth invention according to claim 5 allows for a molded product with an even higher foaming ratio than when only one side is molded back, by molding the movable side and the fixed side, and / or core-back.

[0025] (Explanation of Claim 5) Mold back, or / or core back, is performed on both the movable and fixed sides. The retraction sequence may be simultaneous, but a time delay may also be introduced.

[0026] (Configuration of claim 6) The GCP is evacuated, and the seal mold is vacuumed simultaneously with the mold back and / or core back. The compressed air trapped in the gap between the resin and the mold in the molding space L2 is vacuumed.

[0027] (Effect of claim 6) The sixth invention according to claim 6 involves rapidly exhausting the compressed air that has entered the resin and mold in order to eliminate raindrops and obtain a foamed molded product with a clean appearance. Furthermore, the exhaust speed can be increased by creating a vacuum.

[0028] (Effects of Claim 6) The sixth invention according to claim 6 is that, since the mold backing and / or core backing are performed simultaneously before the cooling and solidification of the surface layer of the molded product, the transferability to the mold is improved and raindrops can be eliminated.

[0029] (Explanation of Claim 6) The sixth invention according to claim 6 involves performing mold backing and / or core backing after exhausting the GCP to evacuate the compressed air that has entered the gap between the resin and the mold, thereby obtaining a molded product without raindrops.

[0030] (Configuration of Claim 7) Vacuuming should be performed after a delay period following mold backing and / or core backing.

[0031] (Effect of Claim 7) A delay time is allowed for vacuuming, so vacuuming is performed only after the mold has been thoroughly evacuated.

[0032] (Effects of Claim 7) By using a vacuum system, a high-expansion-ratio foamed molded product with a clean appearance and no raindrops can be obtained.

[0033] (Explanation of Claim 7) The seventh invention according to claim 7 involves exhausting the GCP, performing mold backing and / or core backing, opening the gas vent, and evacuating. Expanding the mold widens the gas vent, thus increasing the vacuum effect. Moreover, since vacuuming is performed after sufficient exhaust, the vacuuming (reduced pressure) effect is significant. The vacuuming equipment used can reduce the amount of gas used for vacuuming, allowing for a smaller equipment size. This method allows for the production of molded parts with a clean appearance, free from raindrops even on glossy surfaces, without the need for texturing.

[0034] (Configuration of claim 8) The vacuuming process begins simultaneously with the start of exhausting the compressed air from inside the sealing mold.

[0035] (Effect of claim 8) Because a vacuum is used, raindrops caused by pressure can be eliminated.

[0036] (Effects of Claim 8) Because a vacuum is used, a clean, raindrop-free foamed molded product can be obtained.

[0037] (Explanation of Claim 8) The eighth invention according to claim 8 performs vacuuming simultaneously with GCP exhaust without mold backing and / or core backing. To eliminate raindrops and obtain a clean molded product, it is even better to apply a textured finish to the surface of the mold.

[0038] (Configuration of claim 9) Vacuuming of the seal mold and GCP device is started with a delay period.

[0039] (Effect of claim 9) Because a vacuum is used, raindrops caused by pressure can be eliminated.

[0040] (Effects of Claim 9) A clean, raindrop-free foamed molded product can be obtained.

[0041] (Explanation of Claim 9) Vacuuming is performed after a delay period following the exhaust of the GCP. When performing vacuuming according to claims 6 to 9, the mold sealing structure with the ejector pin sealed as shown in Figure 11 has a smaller volume to vacuum, so the effect and effectiveness of vacuuming are greater. When vacuuming is performed without mold backing, etc., if a clean appearance without raindrops is required, it is better to apply a textured finish to the surface of the mold where the appearance is required.

[0042] (Configuration of claim 10) The tenth invention according to claim 10 is characterized in that a program is incorporated into the PLC of the molding machine that controls a GCP device used for foam molding, a device for injecting gas or liquid or both into a heating cylinder, a hollow molding device for performing hollow molding, a pressure molding device for performing pressure molding, etc., and issues operational commands to each of them.

[0043] (Effect of claim 10) Since the PLC of the molding machine contains programs for externally connected devices such as GCP equipment, liquid injection equipment, and equipment for hollow molding and pressure molding, connecting and operating the equipment is easy.

[0044] (Effects of Claim 10) The tenth invention according to claim 10 has programs for the GCP device, liquid injection device, and device for performing hollow molding and pressure molding written into the PLC of the molding machine, so there is no need to prepare an externally connected controller and no need for extra capital investment.

[0045] (Explanation of Claim 10) The PLC program of the molding machine contains programs that issue commands for the operation of the GCP device, the liquid injection device, and the devices that perform hollow molding and pressure molding.

[0046] (Configuration of claim 11) When the mold is closed, a start signal (such as the mold clamping completion signal or the LS signal attached to the mold) is used to open the compressed air valve (number 46) of the GCP device and pressurize the inside of the mold. The pressurization time is pre-programmed in the PLC. When the time is up, the molding machine is programmed to start injecting the foamed resin.

[0047] (Effect of claim 11) The operation (pressure) of the GCP device is initiated by a program in the molding machine's PLC.

[0048] (Effects of Claim 11) There is no need to prepare a separate controller for the operation of the GCP device, as the program is built into the PLC within the molding machine. The system is designed to check the mold clamping and control the pressure inside the mold using a timer, so there is no need to prepare a separate controller, and the operator does not need to move.

[0049] (Explanation of Claim 11) The operation of the GCP (Gas Pressure Control) device's compressed air mechanism is integrated into the molding machine's PLC (Programmable Logic Controller). The compression of the mold and the start of injection are controlled by a timer.

[0050] (Configuration of claim 12) The exhaust of compressed air from inside the mold (by opening valve number 51) is performed by a program in the molding machine's PLC.

[0051] (Effect of claim 12) The molding machine's PLC (Programmable Logic Controller) has a built-in program that sends commands to the GCP (Gas Control Panel) device to perform actions (open the valve and exhaust the gas).

[0052] (Effects of Claim 12) The twelfth invention according to claim 12 is such that the operation program of the GCP device is incorporated into the PLC of the molding machine, so the operator can check the contents of the program and operate it using only the same screen.

[0053] (Explanation of Claim 12) The exhaust of the mold (operation of valve number 51) is performed by a program built into the PLC in the molding machine. There is no need to prepare a separate controller, which requires additional capital investment, to issue operational commands to the GCP equipment.

[0054] (Configuration of claim 13) The PLC of the molding machine has a program built in that, after the compressed air is released, the mold is returned, or / or the core is returned.

[0055] (Effect of claim 13) The PLC of the molding machine has a program built in that controls the operation of the GCP device and the mold-back and / or core-back, so it is controlled by commands from the molding machine.

[0056] (Effects of Claim 13) The 13th invention according to claim 13 is one in which a mold-back and / or core-back program is incorporated into the PLC of the molding machine. There is no need to prepare a separate controller.

[0057] (Explanation of Claim 13) The PLC of the molding machine has programmed operations for the GCP device and for mold-back and / or core-back, and foam molding is performed according to that program.

[0058] (Configuration of claim 14) The PLC of the molding machine has a program built in that, after the compressed air is vented, the mold is returned and / or the core is returned, and then the machine is vacuumed.

[0059] (Effect of claim 14) The PLC of the molding machine controls the operation of the GCP device, and after mold back and / or core back, vacuuming is performed by a command from the molding machine.

[0060] (Effects of Claim 14) The fourteenth invention according to claim 14 has a program built into the PLC of the molding machine for vacuuming after mold-back and / or core-back. There is no need to prepare a separate dedicated controller.

[0061] (Explanation of Claim 14) The molding machine's PLC (Programmable Logic Controller) incorporates programs for the operation of the GCP (Ground Control Panel) device, mold back and / or core back, and vacuum evacuation, and foam molding is performed according to these programs.

[0062] (Configuration of claim 15) The 15th invention according to claim 15 is a screw with an L / D ratio (length divided by diameter) of 15 or more in the heating cylinder of a molding machine used for foam molding.

[0063] (Effect of claim 15) The 15th invention according to claim 15 involves using a screw with an L / D ratio of 15 or more to plasticize a resin and pressurize, dissolve, and finely disperse a foaming gas inside it.

[0064] (Effects of Claim 15) The 15th invention according to claim 15 is a highly compounded screw with an L / D ratio of 15 or more, which allows for optimal pressure dissolution and fine dispersion of foaming gas in the plasticized resin.

[0065] (Explanation of Claim 15) In foam molding, high kneadability is required for the pressurized dissolution and fine dispersion of the foaming gas in the molten resin inside the heating cylinder during the plasticization and metering stages. When using a highly compoundable material with an L / D ratio of 15 or higher, and when the flight is made into a double flight or / or a dreadnought type, the foaming gas is sufficiently pressurized and dissolved and finely dispersed, so that the resulting foamed molded product forms fine foam cells.

[0066] (Configuration of claim 16) The 16th invention according to claim 16 involves plasticizing by applying high back pressure, which causes the foaming gas to be pressurized, dissolved, and finely dispersed. In foam molding, the back pressure applied to the plasticized molten resin inside the heating cylinder is preferably 5 MPa or more.

[0067] (Effect of claim 16) By applying a high back pressure of 5 MPa or more during plasticization (melt mixing, metering), the foaming gas is uniformly pressurized and dissolved, resulting in a foamed resin with uniform and fine dispersion.

[0068] (Effects of Claim 16) By measuring, heating, and melting the resin under a high back pressure of 5 MPa, the melted resin in the heating cylinder is uniformly dissolved under pressure, resulting in a foamed resin with finely dispersed foam properties suitable for foam molding.

[0069] (Explanation of Claim 16) Plasticize while increasing the back pressure to about 5 MPa. During this process, nasal discharge will occur from the nozzle. The nozzle can be fitted with a shut-off nozzle or similar attachment. The weighing process only needs to be completed before the next injection (filling). If the weighing is completed too early, condensation of the foaming gas will begin inside the heating cylinder, so a delay in weighing may be necessary. Sometimes, back pressure is continued even after weighing is complete (back pressure blocking).

[0070] (Configuration of claim 17) To reduce the pressure of the foamed resin filling the molding space, a delay period is taken immediately after filling with the foamed resin to allow for suck-back.

[0071] (Effect of claim 17) By causing the resin to suck back, the pressure of the resin filling the molding space drops rapidly, making foaming easier.

[0072] (Effects of Claim 17) The expansion ratio can be increased by using a suck-back method. This allows for the production of foamed molded products with a high expansion ratio.

[0073] (Explanation of Claim 17) The pressure of the foamed resin filling the molding space is reduced by suck-back, facilitating foaming. The pressure of I-GCP is also reduced, allowing for a larger foamed area inside.

[0074] (Configuration of claim 18) To reduce the pressure of the foamed resin filling the molding space, a delay time is allowed immediately after filling the foamed resin to allow it to breathe.

[0075] (Effect of claim 18) By allowing the resin to breathe, the pressure of the molten resin drops rapidly, making foaming easier.

[0076] (Effects of Claim 18) The foaming ratio can be increased through breathing.

[0077] (Explanation of Claim 18) The pressure of the foamed resin filling the molding space is reduced by bleeding, facilitating foaming. It can also be used in combination with suck-back. The pressure of I-GCP can also be reduced, allowing for a larger foamed area inside.

[0078] (Configuration of claim 19) Polyhydric alcohols, which have a high boiling point, are non-toxic, and can be easily cleaned with water, are used to control the temperature of the mold. For heating, induction (electromagnetic induction) heating is used to heat the metal balls and metal powders inside, and then the liquid is heated by that temperature.

[0079] (Effect of claim 19) This describes a heating method using induction heating. A liquid with a high heat capacity is used.

[0080] (Effects of Claim 19) When using superheated steam, the highest temperature achievable even under pressurization is only about 130°C, and since it is a gas, its heat capacity is low. On the other hand, when using polyhydric alcohols, since they are liquids, their heat capacity is high. Glycerin, a polyhydric alcohol, has a high boiling point, making it convenient to use.

[0081] (Explanation of Claim 19) In foam molding using GCP, increasing the surface temperature of the mold increases raindrops. On the other hand, increasing the surface temperature of the mold also thins the skin layer (the non-foamed surface layer), improves mold transferability, and results in a cleaner appearance (although raindrops are more frequent). Therefore, by exhausting the compressed air, performing mold backing or core backing, and implementing vacuum evacuation, raindrops can be eliminated even when the surface temperature of the mold is high. Using this method, even with glass fiber-reinforced composite materials, if the surface temperature of the mold is raised above the glass transition temperature (Tg) during molding, it is possible to manufacture foam-molded products of glass fiber-reinforced composite materials with little to no glass lifting.

[0082] (Configuration of claim 20) The 20th invention according to claim 20 is characterized in that the foaming agent master batch consists of a resin to be molded, a foaming agent powder, and a varnish compatible with (solubilable) the resin to be foamed, and the foaming agent is supported on the surface of the pellets of the resin to be molded using the varnish.

[0083] (Effect of claim 20) The 20th invention according to claim 20 is a conventional method for manufacturing a foaming agent master batch, in which the resin to be molded is heated and melted, foaming agent powder is added to it, and then it is melt-mixed. However, depending on the type of resin, if the melting temperature is higher than the decomposition temperature of the foaming agent, manufacturing becomes difficult. The method of supporting the foaming agent on the surface of a pellet using a varnish compatible with the resin to be foamed requires a low support temperature (sufficient for the solvent in the varnish to evaporate and the foaming agent powder to dry on the surface of the pellet). Therefore, it can be manufactured regardless of the melting temperature of the resin to be molded when producing the foaming agent masterbatch.

[0084] (Effects of Claim 20) The 20th invention according to claim 20 does not involve heating and melting the resin, thus preventing thermal degradation of the resin. It requires less thermal energy for manufacturing and has economic benefits such as not requiring the use of large-scale equipment (devices, space, etc.).

[0085] (Explanation of Claim 20) Conventional methods for manufacturing foaming agent masterbatches involve heating and melting the carrier resin of the masterbatch using an extruder or kneader, adding the foaming agent, and pelletizing it. However, this melt-mixing method is difficult when the melting temperature of the resin is higher than the thermal decomposition temperature of the foaming agent. In the third invention according to claim 3, resin pellets (the properties are not limited to pellets; bulk is also acceptable) and foaming agent powder are mixed together, and while heating, a varnish compatible with the resin to be foamed is gradually added to the mixture. The solvent in the varnish is evaporated, and the foaming agent powder is supported on the surface of the pellets (attached by the resin in the varnish). Since the resin is not melted or heated, there is no thermal degradation of the resin, and the foaming agent is kept below its decomposition temperature, making it possible to manufacture a foaming masterbatch without any decomposition of the foaming agent. It does not require large-scale equipment and can be manufactured using inexpensive, small, and simple devices such as the rocking mixer shown as an example. While it is best to manufacture separate masterbatches for foaming agents, foaming aids, and bubble nucleating agents and mix them together to achieve the optimal blend, it is also easy to manufacture a foaming agent masterbatch that combines all of these. Furthermore, unlike conventional melt-mixing methods, it is possible to manufacture foaming agent masterbatches with high concentrations of foaming agent (naturally, more foaming agent powder will be loaded with repeated loading).

[0086] (Configuration of claim 21) The 21st invention according to claim 21 is a varnish used in the production of a master batch of a foaming agent for foam molding of resins intended for foam molding, such as AS and ABS, and resins mainly composed of them. The varnish is prepared by dissolving identical AS and ABS in an organic solvent, such as MEK, and adding toluene as needed. This varnish is then used to support pellets of AS, ABS, etc., in order to produce a master batch of a foaming agent.

[0087] (Effect of claim 21) The 21st invention according to claim 21 is that the varnish used in the production of the foaming agent master batch consists of AS in the resin to be foamed and ABS to be foamed, so that no foreign material is introduced into the foamed molded product, thus eliminating problems such as deterioration of physical properties.

[0088] (Effect of claim 21) The 21st invention, as described in claim 21, involves the production of a foaming agent master batch, in which the resin intended for foam molding is AS, ABS, or a resin mainly composed of these, and a compatible (solubilable) AS or ABS varnish is used, so there is no problem of deterioration of physical properties due to the inclusion of foreign materials. Since the production of AS or ABS varnish is simple and inexpensive, a foaming agent master batch produced using this material is inexpensive and does not increase the production cost of the foamed molded product.

[0089] (Explanation of Claim 21) The 21st invention according to claim 21 involves dissolving AS and ABS in a solvent to produce a varnish. A foaming agent powder is supported on the surface of AS and ABS pellets using these varnishes. Since AS and ABS dissolve easily in solvents, instead of using varnish, it is also possible to mix AS and ABS pellets with a foaming agent powder and then add only an organic solvent, such as MEK, to support the foaming agent on the surface of the AS and ABS pellets.

[0090] (Configuration of claim 22) The 22nd invention according to claim 22 uses a varnish obtained by dissolving AS and ABS as an emulsion system or suspension system for support.

[0091] (Effect of claim 22) The 22nd invention according to claim 22 uses emulsion-type and suspension-type substances, so the solvent odor is reduced and the working environment does not deteriorate.

[0092] (Effects of Claim 22) The 22nd invention, as described in claim 22, is a manufacturing method that uses emulsion or suspension systems, which prevents deterioration of the working environment and is environmentally friendly, as it can comply with VOC regulations in Europe and other regions.

[0093] (Explanation of Claim 22) In the 22nd invention according to claim 22, the 21st invention uses varnish dissolved in a solvent. Solvents pose a risk of flammability and have a strong odor, requiring careful handling during use. A small amount of solvent is used to manufacture the varnish, and water or the like is used to create an emulsion or suspension system, which is then used as a material to support the foaming agent powder on the surface of the resin pellets intended for foam molding. Furthermore, in this 22nd invention, emulsion-type and suspension-type materials may be used in combination with varnish dissolved in a solvent. The foaming agent master batches described in claims 4 to 5 can be used with AS, ABS, as well as AAS, ASA, AES, and ACS. Naturally, these AAS and others can also be used to make varnishes.

[0094] (Configuration of claim 23) The 23rd invention according to claim 23 changes the AS and ABS resins intended for foam molding used in the 4th invention to PS, HIPS, and modified PPO(E), and therefore the varnish used is also PS and HIPS, which are compatible (solubilable) with these.

[0095] (Effect of claim 23) The 23rd invention according to claim 23 uses a varnish obtained by dissolving PS and HIPS, which are compatible (solubilable) with the resin to be foamed, using an organic solvent such as MEK, similar to AS and ABS, so that a foaming agent master batch can be manufactured inexpensively and easily.

[0096] (Effects of Claim 23) The 23rd invention according to claim 23 is that the resin to be foamed is PS, HIPS, or modified PPO(E), and the carrier resin (actually pellets) of the foaming agent master batch is PS or HIPS, and the resin to be foamed is of the same quality PS or HIPS, and the PS or HIPS resin that constitutes the master batch during foaming is sufficiently compatible (dissolves) with PPO(E). Furthermore, if there is concern about a decrease in physical properties when using modified PPO(E) for foaming, modified PPO(E) pellets can be used in the production of the foaming agent master batch.

[0097] (Explanation of Claim 23) The 23rd invention according to claim 23 is a polymer blend or polymer alloy obtained by mixing PS, HIPS, PS, and / or HIPS and PPO(E) in which a master batch of foaming agent is produced by supporting these resins with PS, HIPS, or a compatible (dissolving) PS or HIPS varnish.

[0098] (Configuration of claim 24) The 24th invention according to claim 24 is a master batch of a foaming agent used for foam molding of PS, HIPS, and modified PPO(E), wherein PS and HIPS, which are compatible with the resin to be foam molded, are dissolved in a solvent to form an emulsion or suspension system, which is then supported on the PS, HIPS, and modified PPO(E) pellets to be molded.

[0099] (Effect of claim 24) The 24th invention according to claim 24 has the effect of not worsening the working environment during manufacturing, as the master batch of the foaming agent used is manufactured using an emulsion or suspension type resin varnish that is compatible (dissolves) with the resin to be foamed.

[0100] (Effects of Claim 24) The 24th invention according to claim 24 uses an emulsion or suspension system to manufacture a master batch of foaming agent, which reduces the amount of solvent used compared to when varnish is used, thus having the effect of not worsening the working environment. Emulsion-based and suspension-based products pose less risk of ignition and combustion compared to solvent-based products, making them safer to work with.

[0101] (Explanation of Claim 24) The 24th invention according to claim 24 is that the resin to be foamed is PS, HIPS, or modified PPO(E), and the PS or HIPS is dissolved in a solvent beforehand, and an emulsifier is used as needed to form an emulsion or suspension system. This solution is used to support the foaming agent powder onto the surface of PS, HIPS, and modified PPO(E) pellets, thus reducing the amount of solvent used.

[0102] (Configuration of claim 25) The 25th invention according to claim 25 uses a varnish of an acrylic resin or styrene-modified acrylic resin that is compatible (solubilable) with styrene-based resins, which is used in the manufacture of paints, to support the foaming agent powder.

[0103] (Effect of claim 25) The acrylic resin and styrene-modified acrylic resin in the varnish of the 25th invention according to claim 25 are compatible (solubilable) with styrene-based resins such as AS, ABS, PS, HIPS, and modified PPO(E).

[0104] (Effects of Claim 25) The 25th invention according to claim 25 is that the main component of the varnish used, acrylic resin or styrene-modified acrylic resin, is compatible (solubilable) with AS, ABS, PS, HIPS, and modified PPO(E). Only one type of varnish needs to be prepared for the production of the foaming agent master batch, and commercially available paint materials can be reused, making it economical.

[0105] (Explanation of Claim 25) The varnish used in the production of the masterbatch of the foaming agent according to claim 25 of the 25th invention can, for example, be a commercially available paint manufacturing material used for plastic paints. It can be easily supported using a rocking mixer or the other exemplified method. The varnish to be used should be a simple one, consisting only of acrylic resin or styrene-modified acrylic resin. If the varnish contains CAB (cellulose acetate butyrate) or nitrocellulose, CAB is acceptable, but varnishes containing nitrocellulose cannot be used. Nitrocellulose is undesirable because it causes discoloration during foam molding. Discoloration does not occur with CAB.

[0106] (Configuration of claim 26) The 26th invention according to claim 26 is a master batch of a foaming agent manufactured using an emulsion-type or suspension-type acrylic resin varnish, which is used in the manufacture of a master batch of a foaming agent.

[0107] (Effect of claim 26) The 26th invention, as described in claim 26, uses emulsion-based and suspension-based materials, thus improving the working environment.

[0108] (Effects of Claim 26) The 26th invention according to claim 26 uses acrylic resin and styrene-modified acrylic resin varnishes in emulsion and suspension forms, resulting in less odor during the production of the foaming agent master batch, and thus not worsening the working environment. Emulsion-based and suspension-based products pose less risk of ignition and combustion compared to solvent-based products, making them safer to work with.

[0109] (Explanation of Claim 9) (Explanation of Claim 26) The 26th invention, according to claim 26, uses an emulsion or suspension type of acrylic resin or styrene-modified acrylic resin varnish for the production of a foaming agent master batch. Since acrylic resins and styrene-modified acrylic resins are compatible (solubilable) with styrene resins such as PS, HIPS, modified PPO(E), AS, and ABS, it is not necessary to prepare a large amount of varnish during the process. While emulsifiers are used when creating emulsion or suspension-type coatings, the goal is not to achieve high performance in terms of paint or coating film properties, but simply to ensure that the coating adheres to the surface of pellets or other materials during foam molding, is easy to handle, and mixes easily. Therefore, it is perfectly possible to implement this without emulsifiers.

[0110] (Configuration of claim 27) This document describes a method for producing a masterbatch of a foaming agent for PP (polypropylene). PP has high chemical resistance, and few solvents can dissolve PP in its pure form. To make PP soluble in solvents, it must be acid-modified. The 27th invention according to claim 27 involves using acid-modified PP varnish in the production of a master batch of a PP foaming agent, and, similar to the production of a master batch of a foaming agent for styrene-based resins such as HIPS and ABS, supporting the foaming agent powder on the surface of PP pellets intended for foam molding using acid-modified PP varnish.

[0111] (Effect of claim 27) The 27th invention according to claim 27 demonstrates compatibility (solubility) between PP intended for foam molding and acid-modified PP. Even when acid-modified PP varnish is used in the production of the foaming agent master batch and foam molding is performed, the acid-modified PP in the molded resin is compatible (soluble) and finely dispersed in the PP, exhibiting a sea-island structure, and has almost no effect on the physical properties of the PP resin.

[0112] (Effects of Claim 27) The 27th invention according to claim 27 uses PP intended for foam molding and acid-modified PP that exhibits compatibility (solubility). During the heating and melting stage of molding, they melt together, mix in the resin, become finely dispersed, and exhibit a sea-island structure, which hardly affects the physical properties of PP, thus enabling foam molding of PP.

[0113] (Explanation of Claim 27) The 27th invention, as described in claim 27, relates to the manufacture of a master batch of foaming agent for PP. Commercially available master batches of foaming agent for PP use PE as the carrier resin. Therefore, even when using GCP to produce foamed molded products with a clean appearance free of swirl marks, silvering due to the PE occurred near the gate. (See Figure 1) However, since PP has a melting point that is about 20°C higher than PE, even if you try to melt PP and add powdered foaming agents such as bicarbonate, ADCA, and HDCA and knead them together, the foaming agents will decompose thermally during the melt-kneading stage, and even if you pelletize them, the foaming agents inside will have already lost their function as foaming agents. By using acid-modified PP, such as maleic acid-modified PP varnish (which is widely used as an adhesive for PP and as a primer when painting PP molded products), which is compatible with PP, the foaming agent powder can be easily supported onto PP pellets intended for foam molding, in the same way as in the case of HIPS and ABS, thus easily producing a master batch of foaming agent for PP. Furthermore, since the resin is not heated and melted, there is no thermal degradation due to the heat history of the PP.

[0114] (Configuration of claim 28) Claim 27 describes the use of acid-modified PP varnish (solvent-based or acid-modified PP dissolved in a solvent) in the production of a master batch of foaming agent for PP. However, in the 28th invention as described in Claim 28, the varnish (acid-modified PP dissolved in a solvent) is used as an emulsion or suspension type.

[0115] (Effect of claim 28) The 28th invention according to claim 28 is used as an emulsion or suspension system with a small amount of solvent used. Even acid-modified emulsion and suspension-type materials retain their function as adhesives for PP, and therefore exhibit sufficient action to support the foaming agent powder on the surface of PP pellets.

[0116] (Effects of Claim 28) The 28th invention, as described in claim 28, is used as an emulsion or suspension system with a small amount of solvent, so it does not worsen the working environment and reduces the risk of ignition or combustion, allowing for the safe manufacture of master batches of foaming agents for PP.

[0117] (Explanation of Claim 28) The 28th invention according to claim 28 involves supporting an emulsion or suspension mono of acid-modified PP on the surface of PP in the production of a master batch of a foaming agent for PP. Acid-modified PP is compatible (solubilable) with PP intended for foam molding, allowing for the production of a master batch of foaming agent for PP. Similar to claim 27, even if it penetrates and mixes into the PP, it has almost no effect on the physical properties of the PP. Acid-modified PP has high thermal stability, and it has been confirmed in experiments of the present invention (foam molding using a foaming agent supported by acid-modified PP on PP pellets) that it does not cause discoloration or burning of the resin even when mixed into PP and subjected to foam molding.

[0118] (Configuration of claim 29) The 29th invention according to claim 29 is a master batch of a foaming agent used for foam molding, wherein the foaming agent consists only of a foaming agent powder and a resin that constitutes a varnish that is compatible (soluble) with the resin to be foam-molded.

[0119] (Effect of claim 29) The 29th invention, according to claim 29, does not involve supporting foaming agent powder on the surface of pellets, but rather involves mixing varnish and foaming agent powder (in liquid form) and, for example, adding a small amount of powder to a rocking mixer first, then gradually adding the mixture while heating. Using the foaming agent powder added first as a nucleus, a mixture of the foaming agent and the resin component in the varnish grows, resulting in granulation.

[0120] (Effect of Claim 29) The 29th invention according to claim 29 allows for the production of a foaming agent master batch by granulation, resulting in a high concentration of the foaming agent (amount of foaming agent contained in the granules). By using styrene-modified acrylic resin for the acrylic resin or varnish, a foaming agent master batch can be made that can be used with any styrene-based resin such as HIPS or ABS.

[0121] (Explanation of Claim 29) Powdered foaming agents are difficult to handle. Granulating the foaming agent powder using a small amount of varnish makes handling easier. Moreover, since it does not involve conventional melting and kneading, it is possible to easily manufacture products with high concentrations of foaming agent.

[0122] (Configuration of claim 30) The 30th invention according to claim 30 involves granulating a foaming agent powder and a resin to be foamed, or a powder of a resin component, using varnish.

[0123] (Effect of claim 30) The 30th invention according to claim 30 involves granulation using a foaming agent powder, varnish, a powder of a resin to be foamed and molded, and / or a powder of a resin that is compatible (solubilable) with the resin to be foamed and molded. For example, ABS is a blend polymer of AS and butadiene graft copolymerized with A (acrylonitrile) and S (styrene). A foaming agent master batch can be easily produced by mixing AS powder with foaming agent powder and granulating it using varnish. In the case of AS and PS, since they are soluble in solvents, granulation can be performed without using varnish by putting AS powder or PS powder and foaming agent powder into a rocking mixer, mixing them, and spraying, for example, MEK. For example, if you put AS and ABS pellets in, add foaming agent powder, and spray with MEK, the MEK will dissolve the surface of the AS and ABS, so it is possible to manufacture a foaming agent master batch.

[0124] (Effects of claim 30) The 30th invention according to claim 30 also makes it possible to produce a master batch of foaming agent containing a high concentration of foaming agent, compared to the conventional melt-kneading method.

[0125] (Explanation of Claim 30) The 30th invention according to claim 30 is a master batch of a foaming agent manufactured by mixing a foaming agent powder and a resin powder, and granulating the mixture by spraying a solvent or varnish while stirring with a rocking mixer or the like.

[0126] (Configuration of claim 31) The 31st invention according to claim 31 involves separately supporting powders such as a foaming agent, foaming aid, bubble nucleating agent, and pigment / dye on pellets of resin intended for foam molding, and then mixing the supported pellets with the pellets of resin intended for foam molding before use.

[0127] (Effect of claim 31) The 31st invention according to claim 31 involves mixing pellets or the like (both pellets with the material supported and granulated materials) in optimal amounts, thus allowing for optimization of the amount of each material added.

[0128] (Effects of Claim 31) The 31st invention according to claim 31 uses pellets or the like carrying powders of materials exhibiting their respective effects in an optimized formulation, thus eliminating the need for excessive additives and allowing for easy changes in the formulation, resulting in economical effects, stable quality, and improved quality.

[0129] (Explanation of Claim 31) The 31st invention according to claim 31 involves manufacturing each master batch using varnish, solvent, etc., as described in the present invention, adding the optimal amount of additives, and performing foam molding. Since pellets of the resin intended for foaming are not used, the master batch of foaming agent created using acrylic resin and styrene-modified acrylic resin can be made with fewer types of resins because these acrylic resins and styrene-modified acrylic resins are compatible (solubilable) with HIPS, ABS, etc. Using the same method, it is also possible to manufacture a master batch of high-concentration foaming agents for PP using acid-modified PP varnish.

[0130] (Configuration of claim 32) The 32nd invention according to claim 32 is a foamed molded product that is painted for cosmetic purposes, and the foaming agent used does not reduce the adhesion or bonding of the coating film. Problem-free organic foaming agents such as ADCA and HDCA, or water, alcohol, or ether without foaming residue that affects the adhesion or bonding of the coating film are used.

[0131] (Effect of claim 32) The 32nd invention according to claim 32 is selected from foaming agents that do not leave foaming residue or whose foaming residue does not affect the adhesion and bonding of the coating film, so no problems with the adhesion and bonding of the coating film occur.

[0132] (Effects of Claim 32) The 32nd invention according to claim 32 has the effect of simplifying the painting process because the foaming agent used does not affect the adhesion and bonding of the coating film, and therefore painting can be easily started by simply removing dirt attached to the surface with an air blower and removing oil and grease with an alcohol wipe, without having to perform pretreatment (scission) aimed at removing troublesome foaming residue.

[0133] (Explanation of Claim 32) The foaming agent used in foam molding decomposes thermally in a heating cylinder, generating foaming gas. This gas is then pressurized and dissolved in the molten resin within the heating cylinder, causing it to become finely dispersed and impart foaming properties to the molten resin. However, the decomposition residue of the foaming agent penetrates the resin into which the foaming properties have been imparted. On the surface of foam-molded products into which this foaming agent residue has penetrated, foaming residue is observed. If painting is performed without removing the foaming residue, and tests such as salt spray tests, salt immersion tests, humidity resistance tests, and water resistance tests are conducted, blistering and peeling of the paint film occur due to the foaming residue, rendering the product unusable. Experiments have confirmed that the residues of ADCA and HDCA in azo-based foaming agents do not affect the adhesion and bonding of the coating film. Therefore, azo-based foaming agents such as ADCA and HDCA are suitable for the production of foamed molded products in certain painting processes.

[0134] Water boils at 100°C, and ethanol boils at approximately 80°C. When these are measured and added to the molten resin in a heating cylinder during weighing (plasticization), they vaporize due to the heat of the heating cylinder and the temperature of the molten resin, dissolving and dispersing within the molten resin, thereby imparting foaming properties to the resin. However, all of these liquids, such as alcohol, vaporize completely, leaving no residue. Using these liquids as foaming agents solves the problem of adhesion and bonding of the coating film caused by foaming agent residue.

[0135] (Configuration of claim 33) The 33rd invention according to claim 33 states that when a bicarbonate (e.g., baking soda) is used as a foaming agent, the carbonate (sodium carbonate in the case of baking soda) in the foaming residue remains as undecomposed bicarbonate. If paint is applied in this state, blistering and peeling of the paint film will occur due to the foaming residue present on the surface, so these foaming residues are removed using an acidic substance beforehand.

[0136] (Effect of claim 32) The 32nd invention according to claim 32 is that carbonates and bicarbonates are alkaline substances, and therefore are easily dissolved by neutralization upon contact with acidic substances. Foamed molded products using these bicarbonates as foaming agents can achieve sufficient adhesion and bonding of the coating film by undergoing processes such as acid cleaning.

[0137] (Effects of Claim 32) The 32nd invention according to claim 32 is characterized by the fact that the bicarbonate used as a foaming agent is inexpensive, the foaming gas produced is carbon dioxide and water vapor, and the foam cells formed are fine, resulting in a stable foamed molded product. By performing acid cleaning of this molded product, sufficient adhesion and bonding of the coating film can be obtained.

[0138] (Explanation of Claim 32) Although bicarbonates are widely used as foaming agents, if foamed molded products with foaming residue or undecomposed bicarbonates on the surface are painted, the adhesion and bonding of the paint film will decrease. When the paint film is evaluated (e.g., JIS K5600-7-1), blistering and peeling will occur, rendering the product unusable. Carbonates and bicarbonates can be easily removed (dissolved) by immersing them in a weakly acidic solution or wiping them with a cloth containing a weak acid. After acid washing, if necessary, rinse with water, dry, and then paint, sufficient adhesion and bonding of the paint film can be obtained. The acid used for acid cleaning can have a pH of around 6. Raising the temperature of the acid solution to 40°C or higher will also remove grease. Adding an ultrasonic transducer (plate) to the cleaning solution will make it even more effective. Valve rings may also be used.

[0139] [Brief explanation of the drawing]

[0140] [Figure 1] The diagram (photo) shows that silvering occurred near the gate due to the base resin of the foaming agent master batch, and the swirl mark at the end of the flow could not be controlled (contained) due to insufficient GCP pressure (material used: PP). [Figure 2] While swirl marks were controlled (suppressed) with GCP, silver from the base resin of the foaming agent masterbatch appeared near the gate (the material used is PP used for automotive interiors) (the material used is TSOP). [Figure 3] A diagram (photo) showing that swirl marks occurred across the entire surface when GCP (Ground Conditioning) was not implemented (material used: transparent ABS). [Figure 4] The image (photo) shows that GCP was performed, the foam cells were contained, and no swirl marks were observed on the surface, resulting in a smooth surface (transparent ABS material was used). [Figure 5] This cross-sectional diagram (photograph) of a foamed molded product shows that by using GCP, it is possible to confine the foamed layer (reference number 110) inside the foam cell to a smooth skin layer (reference number 111) on the outside (the surface is a smooth skin layer without swirl marks, and the inside is a foamed layer). [Figure 6] A diagram (photo) of carbonated water. [Figure 7] A diagram (photo) illustrating the reason for foaming. [Figure 8] A diagram (photo) illustrating the principles of GCP. [Figure 9] GCP equipment. [Figure 10] A schematic diagram showing a mold structure for foam molding in which the ejector mechanism is enclosed and sealed in a box. [Figure 11] A schematic diagram showing the structure of a foam molding die in which the ejector pin is sealed with a load-operated O-ring or the like. [Figure 12] A schematic diagram showing the dovetail groove for securing the O-ring. [Figure 13] Figure 10 is a schematic diagram showing the structure of a foam molding die, with L1 to L3 of the compressed air space of the die. In Figure 13, L1 is the space of the ejector box, L2 is the space of the molding space, and L3 is the space provided at the bottom of the fixed insert. [Figure 14]Figure 11 is a schematic diagram showing the structure of a foam molding die, illustrating the compressed air spaces L1 to L3 of the mold. In Figure 14, L1 is a space provided at the bottom of the movable insert and its function corresponds to the space of the ejector box L2 in Figure 13, L2 is the molding space, and L3 is a space provided at the bottom of the fixed insert. [Figure 15] GCP equipment. [Figure 16] GCP equipment (with sub-tank 55). [Figure 17] A schematic diagram illustrating the process before core backing (during the filling of foamed resin). [Figure 18] A schematic diagram illustrating the post-core-back (expanded) state. [Figure 19] A schematic diagram illustrating the process before mold-back (when the foamed resin is filled). [Figure 20] A schematic diagram illustrating the process after mold-back (expanded). [Figure 21] CAD-generated drawings of the molded product used in the examples. [Figure 22] CAD-generated drawings of the molded product used in the examples. [Figure 23] A schematic diagram showing a device that heats magnetic fluid using electromagnetic induction. [Figure 24] A schematic diagram illustrating a load-bearing O-ring (assembly diagram incorporating a load-bearing spring). [Figure 25] A schematic diagram illustrating a load-bearing O-ring, showing a cross-section (the opening of the load-bearing spring faces upwards). [Figure 26] A schematic diagram illustrating a load-bearing O-ring, showing a cross-section (the opening of the load-bearing spring faces downwards). [Figure 27] A schematic diagram showing the cross-section of a U(V) shaped O-ring. [Figure 28] A schematic diagram showing a U (V) shaped O-ring. [Figure 29] Diagram (photo) of a commercially available coil spring that serves as a replacement for part number 85. [Figure 30] Diagram (photo) of a commercially available O-ring. [Figure 31] A schematic diagram showing the means of gas pressurization from the fixed side. [Figure 32]A schematic diagram showing the inner core of a gas pin used for gas pressurization. [Figure 33] A schematic diagram showing the outer cylinder of a gas pin used for gas pressurization. [Figure 34] A schematic diagram showing a gas pin used for gas pressurization, assembled with an inner core inside the outer cylinder. [Figure 35] A schematic diagram showing that a gas pressure pin is installed on the surface of a molded product. [Figure 36] This relates to Figure 48, which shows a schematic diagram of a load-type O-ring with one-sided load sealing for the ejector pins, and a diagram showing the shape of the pilot holes and other features (housing dimensions) related to the diameter of each ejector pin. [Figure 37] A diagram showing a method for sealing only one ejector pin. [Figure 38] A diagram showing the connection between the mold and the GCP equipment. [Figure 39] A diagram showing gas vents for the intake and exit of compressed air from the GCP (Glass Pressure Packing) at the parting of a mold. [Figure 40] A diagram showing gas vents for the intake and exit of compressed air from the GCP (Glass Pressure Packing) at the parting of a mold. [Figure 41] A diagram showing the shape of L1 and L3 at the bottom of the nesting box (the passage for compressed air). [Figure 42] A diagram (or table) showing combinations of resin, foaming agent master batches, and foam nucleating agent master batches. [Figure 43] Figure (table) showing the results of observations of the exterior and interior when GCP is not used. [Figure 44] Figure (table) showing observation results of the exterior and interior when using GCP. [Figure 45] Figure (table) showing the evaluation results of the adhesion of the coating film. [Figure 46] Figure (table) showing the evaluation results of the adhesion of the coating film. [Figure 47] Figure (table) showing the evaluation results of the adhesion of the coating film. [Figure 48] A diagram (or table) showing detailed dimensions and other information regarding the installation of a single-sided load type O-ring. [Figure 49] This diagram shows a method for further vacuuming the mold after the compressed air has been released. [Figure 50] A schematic cross-sectional diagram showing the structure of a mold, illustrating the means of compression entry and exit from the parting line. [Figure 51] A schematic diagram showing the structure of a mold, illustrating the means of pressing the product into and out of the mold surface. [Figure 52] A schematic diagram showing a cross-section of Figure 51. [Figure 53] This schematic diagram illustrates a core-back molding process where the fixed mold and the core-back mold are not separated by metal, the movable mold is inserted into the molded product, and after the foamed resin is filled into the molding space, the movable mold is retracted. [Figure 54] Figure 53 is a schematic diagram showing that part number 61 (the movable mold) has been retracted. [Figure 55] A schematic diagram showing a cross-section of a V-ring. [Figure 56] A schematic diagram showing a cross-section of a U-ring. [Figure 57] A schematic diagram showing a cross-section of a PL sealing mechanism, where the V-ring opening is oriented in the PL direction, and a regular circular O-ring is also provided. [Figure 58] A schematic diagram showing a cross-section of a PL sealing mechanism, where the U-ring opening is oriented in the PL direction, and a regular circular O-ring is also provided. [Figure 59] A V-ring opening is oriented towards the PL (partial line) direction to seal the pressurized gas within the molded space, while another V-ring is oriented in the opposite direction to the PL to prevent outside air from entering through the PL mating surface when vacuuming the PL. This schematic diagram shows a cross-section of the PL sealing mechanism, also indicating the use of a standard circular O-ring. [Figure 60] A schematic diagram showing a cross-section of the sealing mechanism for the parting line (PL) is provided, with the opening of a U-ring facing the PL direction to seal the pressurized gas inside the molded space, and another U-ring facing the opposite direction from the PL to seal the PL from outside air entering through the mating surface when vacuuming the PL. In addition, a regular circular O-ring is also provided. [Figure 61] A schematic diagram of the V-rings shown in Figure 55, where the V-rings are placed on both the left and right sides and integrated into a single unit. [Figure 62]A schematic diagram of the case where the U-rings in Figure 56 are provided on both the left and right sides and integrated into one unit. [Figure 63] A schematic diagram of a device that performs vacuuming (vacuum device, vacuum pumping device). Modes for carrying out the invention

[0141] (Definition of terms) First, we define the terms used in this invention.

[0142] (less than, less than or equal to, and greater than or equal to) "Less than" does not include the value shown below. "Less than or equal to" includes the value shown below. "Greater than or equal to" includes the value shown below. For example, "less than pH 7" does not include 7, and the solution is acidic, not neutral (pH=7). "pH 7 or less" includes 7, and therefore indicates both neutral and acidic solutions.

[0143] (Applicable products, etc.) The present invention is applicable to any resin molded product made by injection molding, casting, or block molding, regardless of material, shape, or intended use. In office automation equipment, home appliances, and amusement machines, styrene-based resins, or polymer alloys and blends containing styrene-based resins are primarily used. In vehicles, olefin-based resins, or polymer alloys or blends containing olefin-based resins are primarily used. In housing, furniture, and general merchandise, polymer alloys or blends containing thermoplastic resins such as styrene-based resins, olefin-based resins, vinyl-based resins (represented by polyvinyl chloride), ester-based resins, and amide-based resins are primarily used. Molded products using recycled materials, particularly thermoplastic resins recovered from the market and modified or altered to create new molding materials, are also covered. Foam molding, compared to solid molding, offers higher dimensional stability (= repeatability of the molded product's dimensions) because it does not use holding pressure, making it suitable for the use of recycled thermoplastic resins. IC trays made of modified PPO(E) with acetylene black and other materials can be made lighter by foam molding, thus reducing the energy required for transport during burning, inspection, and other processes.

[0144] The resins usable in this invention are listed in the Chemical Daily's "Plastic Molding Materials Trade Handbook - Properties Database" (1999 and 2012 editions). The present invention applies to any type of thermoplastic resin for molding. Examples of thermoplastic resins include polystyrene resins obtained by polymerizing styrene monomers, such as polystyrene (PS), high-impact polystyrene (HIPS), styrene resins which are copolymers of nitrile monomers and styrene monomers, such as acrylonitrile-styrene copolymer (AS), resins consisting of nitrile monomers, styrene monomers, and butadiene rubber, such as acrylonitrile-butadiene-styrene copolymer (ABS), AES which uses olefin rubber instead of butadiene rubber, ASA (AAS) which uses acrylic rubber instead of butadiene rubber, polyethylene (PE), and polypropylene. It is also possible to carry out this process using polyolefin resins such as PP, engineering plastics such as polyphenylene oxide (PPO), polyphenylene ether (PPE), styrene-modified polyphenylene oxide (m-PPO), styrene-modified polyphenylene ether (m-PPE), polycarbonate (PC), polyamide (PA), polysulfone (PSF), polyetherimide (PEI), and polymethyl methacrylate (PMMA), as well as polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), and vinyl resins such as polyvinyl chloride (PVC).

[0145] Thermoplastic resins and / or thermoplastic elastomers may be mixed in groups of two or more to form polymer blends or polymer alloys. Polymer blends or polymer alloys are manufactured, for example, by screw kneading in an extrusion molding machine.

[0146] The resin of the present invention may use compounding agents listed in the Rubber Digest Handbook of Rubber and Plastic Compounding Agents, March 1989 (latest edition), 1993, and December 2003 (revised second edition), as long as it does not impair its function. Other resins and additives used when compounding the resin include, for example, pigments, dyes, reinforcing agents (glass fiber, carbon fiber, etc.), fillers (carbon black, silica, titanium dioxide, talc, etc.), heat-resistant agents, anti-aging agents, anti-oxidation agents, anti-ozone degradation agents, anti-ozone degradation agents, weathering (light) agents (ultraviolet absorbers, light stabilizers), plasticizers, foaming aids, foaming nuclei, lubricants, slip agents, internal release agents, release agents, anti-fogging agents, crystal nucleating agents, flame retardants, flame retardant aids, flow improvers, antistatic agents, compatibilizers, and solvability agents.

[0147] In this invention, "resin" refers to all thermoplastic resins (TPR), thermosetting resins (TSR), TSE (thermosetting elastomer), TPE (thermoplastic elastomer), and rubber. Thermoplastic resins exhibiting thermoplasticity, or / or TPE, are referred to as "thermoplastic resins." Thermosetting resins, rubber, and TSE that exhibit thermosetting properties are referred to as "thermosetting resins."

[0148] The main technology of this invention, GCP, will now be explained. The action and effect of GCP {It traps the foam cells inside, and a clean skin layer (non-foamed layer, a layer where foaming on the surface is suppressed by the action of GCP) is formed on the outside (surface).} This is shown in Figures 2 and 6 when PP is used, and in Figure 4 when transparent ABS is used so that the internal foam cells can be seen. Figure 5 is a cross-section of a foamed molded product in which GCP was performed using PP. The reference numbers in Figures 1 to 5 indicate the following: Reference number 1 is a side gate, with one on each side of the opening (two locations). Reference number 2 indicates that, as described above, silver (lifting of the PE surface) has occurred in GCP molding using PP due to the foaming agent master batch (abbreviation; MB). Reference numeral 3 indicates that swirl marks cannot be suppressed if the GCP pressure (pressure inside the mold) is low or if the exhaust timing is too early. Reference numeral 4 indicates that swirl marks occur on the entire surface when foam molding is performed without using GCP. ADCA was used as the foaming agent in Figures 1 to 5. No foaming nucleating agents or foaming aids were used. The results obtained with baking soda were no different from those with ADCA. Similar results were obtained with potassium bicarbonate as well. When ADCA and baking soda are used together, the foam cells become finer compared to when ADCA is used alone. Increasing the GCP pressure also helps to contain and confine the foam residue within the molded product. As a result, it is hypothesized that using high GCP pressure may allow for the containment of unfoamed foaming agent and foam residue even in foamed molded products using sodium bicarbonate, making painting possible.

[0149] (Compatibility and compatibility) "Compatibility" refers to the property of resins mixing at a molecular level (for example, sugar dissolving in water), while "compatibility" is defined in this invention as the property of one resin filling in another, resulting in a sea-island structure. Compatibility and compatibility are collectively expressed as compatibility (solubility).

[0150] {Molding equipment (units, devices)} The "molding apparatus" used in this invention refers to the GCP apparatus, hollow molding and pressure molding apparatus (a device for separating nitrogen gas from the air, a device for compressing nitrogen gas, a device for injecting and ejecting compressed nitrogen gas to obtain hollow molded and pressure molded products), GCP, mold back, core back, recession, recess, breathing, screw suck back after injection (for the purpose of reducing the pressure of the resin filled into the mold), etc., and an injection molding machine in which a program to control these devices is written (integrated, installed) into the sequencer of the injection molding machine so that operations such as hollow molding and pressure molding can be performed, sealed molding dies as shown in Figures 10 and 11, etc., and GCP apparatus as shown in Figures 9, 15, 16, and 49 {The injection molding machine of this invention has a program installed that commands the opening and closing of the pressure valve, exhaust valve, and vacuum valve (reference number 141) as shown in Figures 9, 10, 11, and 49. This includes the mold shown in Figure 50, the mold heating device shown in Figure 23, shut-off nozzles that operate using mechanisms such as hydraulic, pneumatic, mechanical, and spring types, a device for supporting a foaming agent on resin pellets, a device for mixing and granulating foaming agent powder ("powder" refers to a state in which the solid has become fine, while "powder" refers to a state in which many powders have aggregated) and resin powder.

[0151] (molding material) The term "molding material" used in this invention refers to thermoplastic resins and other additives used in their manufacture, such as reinforcing agents, foaming agents, foaming aids, and foam nucleating agents, typified by glass fibers. This invention can also be carried out with thermosetting resins.

[0152] (merchandise) The foaming agent master batch supported by the foaming agent, the foaming agent granulated from the foaming agent powder and the resin powder, and the foaming molded product with a smooth surface produced using the GCP apparatus shown in this invention can all be produced using injection molded products, block molded products, and cast molded products, which are mainly composed of thermoplastic material. These foaming molded products are widely used in automotive parts, home appliances, office automation equipment, housing equipment, other general merchandise, and amusement machines.

[0153] "Molding space" refers to the space filled with foamed resin and / or non-foamed resin in injection molding, block molding, or casting. "Cavity" refers to the interior, space, or volume (vol) of the molding space. "Mold cavity" is synonymous with "molding space." Sometimes it is simply referred to as "cavity."

[0154] "Injection molding" refers to the process of filling or injecting foamed resin and / or non-foamed resin into a molding space.

[0155] "Filling" in the molding process refers to filling the molding space with foamed resin and / or non-foamed resin. Filling with a volume less than the volume of the molding space is called a short shot or short mold. Filling with an equivalent volume is called a full shot or full pack. Filling with a volume greater than the volume of the molding space is called an over shot or over pack. If holding pressure is applied to the resin from the heating cylinder of the molding machine after a full shot to reduce sink marks or improve transferability, it should be clearly indicated that holding pressure was used. In the case of block molding, the distinction between non-pressurized and pressurized should be clearly indicated, such as "non-pressurized after filling" or "pressurized after filling."

[0156] "Resin in the heating cylinder" refers to thermoplastic resin in a solid state such as pellets, bulk, or powder before heating and melting, during the plasticization process, or in a molten state after plasticization is complete, within the heating cylinder of a molding machine (injection molding machine, extrusion molding machine, casting molding machine, etc.).

[0157] Gas Counterpressure (GCP) "GCP" refers to a method and process in which, as shown in Figures 10 and 11, pressure is applied to the inside of a sealing mold (such as the molding space) with gas at a pressure higher than atmospheric pressure. Under this pressure, a foamed resin, which has been imparted foaming properties using gas, liquid, or solid foaming agents (either individually or in combination), is injected and filled. During the filling process (the timing of exhaust varies depending on the type of resin, type of foaming agent, amount of foaming agent added, type of foaming gas, GCP pressure, etc., but based on the inventor's experience, even if exhaust is started when the foamed resin is 90% or more filled into the molding space, it takes time for the exhaust to be completely released, and the time it takes for the foaming gas inside the resin to come to the surface and form swirl marks is slightly delayed, so a clean molded product without swirl marks on the surface can be obtained), the gas introduced into the mold is exhausted after the filling is complete. This means that a molded product (foamed structure) can be obtained in which the surface has a smooth and clean skin layer (non-foamed layer) without swirl marks (foamed stripes), and the interior has a foamed layer. Alternatively, GCP can also refer to the act or process of pressurizing a sealing mold with a gas at or above atmospheric pressure. GCP is also sometimes called "pressurized gas," which can refer to pressurizing the inside of the mold to a pressure above atmospheric pressure, or the gas placed inside the mold.

[0158] The means of applying compressed air to the GCP mold are shown in Figures 10 and 11, which illustrate the application of compressed air from the parting line into the molding space. However, other methods are also possible, such as using a double-layered ejector pin to apply compressed air through the gap between the inner core and the outer cylinder. If the ejector pin is made of gas (product name) and its tip is made of sintered metal, compressed air can be applied to the molding space by allowing the compressed air to pass through. In this case, the compressed air is applied to the gap in the ejector plate, which is made to withstand the compressed air pressure. In this case, the mold structure should be such that the ejector pin in Figure 11 is sealed with a load-type O-ring as shown in Figures 24 to 30. A double-layered insert (internal part) of approximately φ50 mm can be placed in a part that is not the garment surface, and compressed air can be introduced through the gap. In this way, the compressed air in the molding space is not only from the parting gap, but the exhaust is carried out by the force of the molten resin filling (= being filled) which transfers the compressed air in the molding space from the parting to another location, for example, reference numeral 55 in Figure 6. For example, in Japanese Patent Publication No. 2010-184401 (P2010-184401A), while it is possible to pressurize the mold, it is impossible to transfer the pressurized gas, which would interfere with the resin filling process, to another location. This method can cause short molds, discoloration, and burning.

[0159] "Supporting" refers to the process of attaching other substances, such as powders of foaming agents, foaming aids, foam nucleating agents, and / or pigments, and other additives used in this invention, to the surface of resin pellets using a binder such as paint varnish or doped cement made by dissolving the resin to be molded in a solvent. For AS and ABS (including AAS, ASA, AES, and ACS), the binder is a doped cement or varnish made by dissolving AS, ABS, acrylic resin, or styrene-modified acrylic resin in a solvent. If the resin to be molded is PS, HIPS, or modified PPO(E), the binder is a doped cement or varnish made by dissolving PS, HIPS, acrylic resin, or styrene-modified acrylic resin in a solvent. In the case of PP, acid-modified or halogenated PP, or maleic acid-modified PP (for example, modified using maleic anhydride) is dissolved in a solvent or emulsified with water and used as a binder.

[0160] (binder) A "binder" is a substance that acts as an adhesive when supporting pellets intended for foam molding on the surface, by blending foaming agents, foam nucleating agents (in powder form), decomposition accelerators, etc. It is also a substance that acts as an adhesive when mixing these foaming agent powders with the resin powder intended for foam molding, solidifying and granulating them. Examples of binders include, for ABS, HIPS, and modified PPO(E), doped cement made by dissolving AS, ABS, PS, and HIPS with solvents such as MEK, commercially available styrene-modified acrylic resin varnishes for paints, and styrene-modified acrylic resin emulsions and suspensions. For PP, examples include varnish made by dissolving maleic acid-modified PP in a solvent, and maleic acid-modified PP emulsions and suspensions.

[0161] {Suspend the mixture using a foaming agent powder.} A suspension is also a mixture of an organic foaming agent such as ADCA or HDCA powder and an inorganic foaming agent such as baking soda, in a solvent-based varnish that is insoluble in the aforementioned varnish. Alternatively, a solution of ADCA or HDCA dispersed in a water-based emulsion may be used. A varnish containing water-soluble baking soda dissolved in an emulsion may also be used. These varnishes, when sprayed onto heated pellets, use varnishes containing (dispersed or dissolved) foaming agents, allowing them to be similarly supported on the pellet surface. Granulation can also be achieved without using pellets by adding a small amount of foaming agent powder beforehand and spraying while heated. By placing pellets in a rocking mixer and spraying them with a suspension agent, a master batch for foaming can also be produced. Alternatively, pellets and suspension agents can be added together and stirred while heating.

[0162] "Acid modification" refers to the process where, since PP is insoluble in most solvents, when supporting PP pellets on the surface of the PP pellets of this invention, a resin varnish compatible with the PP to be molded is used. When the resin to be molded is PP, the PP that is compatible with PP is modified so that it can be dissolved and finely dispersed in solvents and water. Generally, PP can be modified using maleic acid, acrylic acid, chlorine (Cl), bromine (Br), etc. When halogens such as chlorine and bromine are used, there is a risk that they will decompose in the heating cylinder during foam molding, releasing halogens and potentially corroding the heating cylinder, screw, mold, etc., as well as causing discoloration of the PP. Maleic acid and similar acids are weak acids, so when PP is acid-modified using these acids, even if the acid is released, there is little to no risk of corrosion of the heating cylinder, screw, mold, etc. To determine whether acid-modified PP can be used as a binder agent for supporting in this invention, 1 wt% to 5 wt% (or 1 mass% to 5 mass%) of the acid-modified PP is supported on top of PP pellets, and the suitability for use is determined by purging the supported PP in an injection molding machine and checking whether discoloration or burning occurs in the purged mass. The purged mass is observed using a transmission electron microscope (TEM) to check the dispersion morphology of PP and maleic acid modification, and whether or not there is any peeling at the interface. The PP intended for actual molding is mixed with the maleic acid modification (taking into account the amount that will be incorporated when used as a foaming agent), and it is confirmed whether the physical and chemical properties of the PP remain within the range of use. Acid modification of PP lowers its melting point. When PP pellets, a foaming agent powder, and acid-modified PP powder are mixed and heated, the acid-modified PP, with its lower melting point, melts. The molten acid-modified PP acts as a binder, which can then be supported on the surface around the PP pellets. If you first put in only PP pellets and heat them until the surface melts, and then add the foaming agent powder, you can achieve some degree of support.

[0163] "Raindrop" refers to a specific surface defect that occurs when GCP (Good Plastic Processing) is performed. It occurs when molten resin is filled into a mold, and the pressurized gas used to suppress foaming on the surface of the foamed resin is drawn into the molded resin during the filling process. This gas then seeps into the gap between the molten resin and the mold, resulting in a depression on the surface of the molded product.

[0164] (Vacuuming) "Vacuuming" refers to the method of using a vacuum pump to suck out the compressed air inside the mold, or the method of using a vacuum pump to draw the compressed air into a tank (sub-tank) that is larger than the volume of the sealed mold's compressed air. In GCP, compressed air is effective in suppressing surface foaming, but it is an obstacle to resin filling, causing raindrops. Texture processing or widening the gas vents in the parting lines can be used to allow the compressed air inside the mold to be exhausted smoothly. After exhausting the GCP, methods such as 0.1mm or 0.2mm mold backing can be used to widen the gas vents. The effect is further enhanced if vacuuming is performed using the compressed air gas circuit after mold backing.

[0165] To avoid raindrops, measures such as lowering the mold surface temperature, lowering the resin viscosity (i.e., lowering the resin temperature), and slowing the filling speed to reduce the entrapment of compressed air were taken, but all of these reduced moldability. However, this method (either performing mold-back after GCP exhaust, or performing vacuum evacuation simultaneously with mold-back, with a slight delay) solved the raindrop problem.

[0166] Figure 49 shows a method to increase the foaming ratio and eliminate raindrops by further vacuuming after exhausting the compressed air from inside the mold. The gas compressed by reference numeral 43 is pressed into the mold by closing the seal mold shown in Figures 10 and 11, opening the injection valve reference numeral 46, and passing through the circuit reference numeral 138 (reference numerals 49, 52, etc.), pressurizing the inside of the mold to a pressure greater than atmospheric pressure (compressed air). The pressure is maintained while filling the foamable resin while pre-pressurizing the molding space (referred to as "pressurized air" or "compressed air"). However, the pre-pressurization of the molding space suppresses foaming on the surface, and swirl marks do not occur. Although the type of resin, type of foaming agent, amount of foaming agent added, type of foaming gas, and timing of GCP exhaust vary, the inventor's experience indicates that the pressure of the compressed air needs to be sufficient to suppress (inhibit) the foaming of the foaming resin filled in the molding space. This pressure should be above atmospheric pressure, preferably 0.6 MPa or higher. In this embodiment, when air was used as the compressed air, the pressure was set to 0.8 MPa to 1.5 MPa. Higher pressures are acceptable, but increasing the pressure of the compressed air makes it easier for raindrops caused by compressed air trapped during resin filling to occur and increases their frequency.

[0167] In a pressurized molding space, a foamed resin, imparted with foaming properties using gaseous, liquid, or solid foaming agents (sometimes used individually, or in combination with gas and solid, liquid and solid, etc.), is filled. During filling, immediately after filling is complete, or after a short period of time, valve 46 is closed and valve 51 is opened to exhaust the compressed air into the atmosphere. Generally, this is the GCP process shown in this invention. However, valve 51 is also closed and valve 141 is opened to draw the air into tank no. 142, which has been pre-pressurized using vacuum pump no. 144. In this case, the mold is molded back by about 0.1 mm to 0.3 mm, widening the PL (parting line). This widens the resulting gas vent, allowing for the forced exhaust of compressed air that has entered the gap between the mold and the resin, thus preventing raindrops. In this case, the O-ring labeled 33, which is installed on the parting (label 60), needs to be of a larger diameter to ensure that it does not lose its sealing function (i.e., the parting is molded back to create a gap in the parting, maintaining sealing properties so that air does not enter through the opened parting even when vacuum is applied). Label 136 indicates the flow of compressed air pressurizing the inside of the mold, and label 137 indicates the gas pressurizing the inside of the mold. Label 139 indicates the flow when compressed air is exhausted into the mold, and label 140 indicates the flow of compressed air when vacuum is applied. Label 145 is a pressure gauge for checking the degree of pressure reduction in tank 142, 143 indicates the flow of gas in 142 that is sucked in by the vacuum pump, and label 135 indicates the gas compressed by the compressor that is sent into Figures 15 and 16. Reference numeral 146 is a check valve installed in the circuit that pressurizes the inside of the mold, reference numeral 147 is a check valve installed in the pressurized air exhaust circuit, and reference numeral 148 is a check valve installed in the vacuum circuit. The check valves reference numerals 146, 147, and 148 do not necessarily need to be installed if the opening and closing of valves 51 and 133 are synchronized.

[0168] (Combination of GCP and hollow molding) The foamed resin filling the molding space is first hollowed out using high-pressure gas, and then the gas is released, initiating foaming inside. In this case, the ejector pin has a double structure, and high-pressure gas is introduced. The gas is released by opening the exhaust valve on the high-pressure gas device. Lowering the ejector plate and retracting the gas pin increases the exhaust speed, so the high-pressure gas introduced inside is completely released, instantly resolving the problem of swelling and rupture.

[0169] The present invention can also be implemented in combination with pressure molding (a method of introducing high-pressure gas into the gap between the mold and the resin, thereby increasing the transferability to the opposite side of the pressurized side using the pressure of the high-pressure gas).

[0170] Foaming agents can exist as gases, liquids, or solids, and are broadly classified into physical foaming agents and chemical foaming agents, each of which has inorganic and organic types. Among chemical foaming agents, inorganic thermal decomposition types include bicarbonates, carbonates, nitrites, hydrogen compounds, hydrogen compound carboxylic acids, and carboxylates. Sesqui(3 / 2) sodium carbonate (chemical name: sodium sesquicarbonate, chemical formula: Na2CO3·NaHCO3·2H2O) contains 2 moles of crystal water (nowadays referred to as "hydrate" rather than "crystal water") which decomposes upon thermal decomposition of NaHCO3 into carbon dioxide and water vapor. Of course, these 2 moles of crystal water also vaporize in the heating cylinder, and this water vapor acts as a foaming gas. Micro-balloons are also included as foaming agents in this invention, and can be supported around resin pellets to be molded using the method of this invention (supporting method) with a binder, and manufactured as a foaming agent master batch.

[0171] Organic thermal decomposition type foaming agents include azo compounds, hydrazine derivatives, semicarbazide compounds, azi compounds, nitroso compounds, and triazole compounds, while reactive type foaming agents include isocyanate compounds. Examples of these include introducing nitrogen gas, carbon dioxide, etc., individually or in combination as a composite gas into the resin inside the heating cylinder, such as MuCell and AmoTec, and liquid foaming agents such as water, ethanol, sodium bicarbonate aqueous solution, potassium bicarbonate aqueous solution, and sodium citrate aqueous solution. Commercially available foaming agents include baking soda, potassium bicarbonate, ADCA (azo dicarboxylic acid amide), HDCA (hydro dicarboxylic acid amide), azo dicarboxylate (Ba salt of ADCA, Ba salt of HDCA), DPT (dinitroso pentamethylenetetramine), OBSH (P-P'-oxybis(benzenesulfonyl hydrazide)), and AIBN (azo bis-isobutyronitrile). Details regarding foaming agents and foam molding can be found in "Various Polymers and Foam Molding Technologies," published by the Technical Information Association of Japan in August 1993. In this invention, in order to clarify the properties of foaming agents, substances that are gaseous at 23°C and 1 atmosphere are classified as "gaseous foaming agents (e.g., nitrogen gas used in MuCell)", substances that are liquid are classified as "liquid foaming agents (e.g., ethanol, sodium bicarbonate solution)", and substances that are solid are classified as "solid foaming agents (sodium bicarbonate, ADCA, etc., or master batches of foaming agents containing these)". Commercially available foaming agents include, for example, Polyslene, AdvanCell, and FineBlow (all are trade names, and their solid form is pellets) as foaming agent master batches.

[0172] When using a liquid foaming agent with a thermoplastic resin, the optimal volume is measured (weighed) relative to the weight of the molded product, injected into the thermoplastic resin in the heating cylinder, and vaporized, thermally decomposed, and / or chemically reacted by the temperature of the heating cylinder and the inside of the heating cylinder, the temperature of the molten thermoplastic resin inside the heating cylinder, and / or the temperature of the mold, or decomposed and / or chemically reacted without requiring heat, thereby generating a gas useful (effective) for foaming.

[0173] The generated gas is finely dispersed and / or dissolved under pressure in the thermoplastic resin inside the heating cylinder. As a result, the thermoplastic resin inside the heating cylinder becomes a foamy thermoplastic resin. This can then be filled into a molding space 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 a resin that has been imparted foaminess by dispersing and / or dissolving a foaming gas in the resin inside the heating cylinder.

[0174] "Foaming" refers to the process by which liquid foaming agents or commercially available foaming agents generate gases useful for foam molding, such as water vapor, alcohol vapor (gas), organic solvent vapor, carbon monoxide, carbon dioxide, nitrogen gas, and hydrogen, through physical changes such as vaporization, thermal decomposition, or chemical reactions. "Foaming" refers to the process of finely dispersing and / or dissolving a foaming gas in a molten thermoplastic resin under pressure, and then reducing the pressure to form foam cells inside and / or on the surface of the thermoplastic resin. In the case of thermosetting resins, heating a foaming agent causes it to vaporize, decompose, and undergo chemical reactions, generating a foaming gas that forms foam cells inside and / or on the surface of the thermosetting resin. Molded products that have a foamed layer inside and / or on the outside due to foaming in this way are called foamed molded products.

[0175] In other words, "foaming" refers to the process where foaming gas is suppressed by external pressure, such as GCP, back pressure, or injection pressure (a state in which it is compressed and finely dispersed in the resin, or / or dissolved under pressure), and then, as the external pressure decreases or disappears, the volume of foaming gas in the resin increases, or / or the dissolved foaming gas turns into a gas. Furthermore, "foaming" also refers to the process in which foaming thermoplastic resin is extruded from a heating cylinder to foam, or the process in which foaming gas is generated by the vaporization, thermal decomposition, or chemical reaction of a liquid or solid foaming agent.

[0176] "Foamable resin" refers to a thermoplastic resin in a molten state in which a foaming gas useful for foam molding is finely dispersed and / or melted under pressure. In other words, "foamable resin" refers to a thermoplastic resin containing a gaseous foaming agent, a liquid foaming agent, or / or a commercially available foaming agent. In this invention, we will describe the state of the resin as accurately as possible, such as "a thermoplastic resin with foaming properties in a molten state," "a thermoplastic resin containing a foaming agent, or a thermosetting resin containing a foaming agent," including whether it has foaming properties and whether it contains a gaseous, liquid, or / or commercially available foaming agent.

[0177] A "foamed molded product" refers to a resin molded product that has discontinuous foam cells inside, obtained by molding a thermoplastic resin that has been given foaming properties. The size of the foam cells is 1,000 μm (micrometers) or less. In this invention, even if hollow portions and foam cells are mixed, the product is still considered a foamed molded product.

[0178] "Combined use" refers not only to using something alone, but also to using it together with or combining it with something else. For example, while one molding process method may be effective on its own, it can also be used in combination with other methods (such as GCP and hollow molding, or GCP and pressure molding), allowing for synergistic effects or improvements in the effects of one or both. Foaming agents may also be used in combination with several other types, rather than alone. They may also be used in combination with commercially available foaming agents. Foaming agents in gaseous, liquid, and solid forms may also be used in combination.

[0179] A "foaming aid" is a substance used to lower the decomposition temperature of a foaming agent or to accelerate its decomposition. Examples of foaming aids for organic foaming agents include zinc stearate, barium stearate, metal soaps, urea (which has the effect of lowering the decomposition temperature of ADCA), and zinc oxide. Inorganic and organic acids (such as citric acid) used in the decomposition of carbonates and bicarbonates can also be considered foaming aids.

[0180] A "foaming nucleating agent" is a substance mixed with the resin and foaming agent to be molded, for the purpose of forming fine foam cells (defined in this invention as foam cells with a diameter of 2000 μm or less). Examples include zinc oxide, silica, talc, titanium dioxide, calcium carbonate, carbonates such as barium carbonate, and sulfates such as calcium sulfate and barium sulfate. Resin additives, such as pigments, also act as foaming nucleating agents. Alkali metal salts of organic acids, especially monosodium dihydrogen citrate and monopotassium dihydrogen citrate, act as effective foaming nucleating agents.

[0181] The "foaming agent mixing ratio" is expressed as the ratio of the weight or volume of the foaming agent to the weight or volume of the resin to be molded, with the weight or volume of the foaming agent set to 1. For example, when using 2 wt% or 2 vol (volume) of liquid foaming agent relative to the resin, it is expressed as 2:100 (or 1:50 or 1 / 50), or 2 wt%, 2 vol%, etc.

[0182] (Masterbatch of foaming agent) Commercially available foaming agents use inorganic substances such as baking soda and potassium bicarbonate, while organic substances such as ADCA and DPT are in powder form. When using these powdered foaming agents, before use, mix the powdered foaming agent with paraffin oil, olive oil, rapeseed oil, etc., onto the resin pellets to be foamed (using a tumbler or similar device) to spread the foaming agent around the pellets before use. This spreading method is acceptable for small quantities, but when the amount of resin used increases, spreading becomes a troublesome task. A master batch of the foaming agent is manufactured using a resin that is compatible with the resin to which the foaming agent is to be blended. In the case of a masterbatch, the masterbatch is shaped like the resin to be foamed (generally a pellet), so the optimal amount (the optimal amount of foaming agent to be added to the masterbatch) can be easily stabilized using a tumbler, automatic coloring device, etc., and as a result, foamed molded products with a stable foaming ratio can be obtained. The resin used for the master batch of the foaming agent and foaming nucleating agent used in the present invention {the resin as the main component of the master batch (referred to as carrier resin, base resin, etc.)} needs to have compatibility with the resin to be blended.

[0183] "Compatibility (miscible)" refers to the property that, in the case of thermoplastic resins, respective resins mix at the molecular level during the heating and melting stage. For example, AS (acrylonitrile-styrene copolymer) is miscible with ABS (terpolymer of acrylonitrile-butadiene-styrene); PS (polystyrene) and HIPS (high-impact polystyrene) are miscible with PPO (polyphenylene oxide) and PPE (polyphenylene ether). Since PPO and PPE have substantially the same molecular structure (oxidized polymer of phenol monomers, for example, methylated or ethylated phenol monomers), they are collectively referred to as PPO(E) in the present invention. PPO(E) modified or denatured with HIPS and / or PS (blended to form a blend polymer or polymer alloy) is referred to as modified PPO(E) or m-PPO(E).

[0184] "Compatibility (compatible)" refers to the case where resins are not miscible with each other, but one resin is dispersed in the other resin and forms a sea-island structure or other structures. For example, the B rubber in ABS {a polymer (macromolecule) obtained by graft-copolymerizing acrylonitrile and styrene on butadiene rubber} exhibits compatibility. When resins are miscible or compatible, the physical properties do not decrease, or only a small decrease occurs. In the present invention, miscibility and compatibility are described as compatibility (miscible / compatible) in the present invention. Compatibility (miscible / compatible) refers to cases indicating miscibility and / or compatibility.

[0185] {Polypropylene (PP)} This invention describes the PP that can be used in this invention. PP is a polymer of propylene, and depending on the difference in stereoregularity, polypropylenes with different stereoregularities (tacticity) such as isotactic, syndiotactic, and atactic can be synthesized. In terms of copolymerization with copolymers (mainly ethylene), PP is classified into three types: homopolymer, random copolymer, and block copolymer. Homopolymer is a single polymer of propylene. Polymerization is carried out using propylene and hydrogen as a chain transfer agent. Depending on the difference, it can have n-butyl groups or i(iso)propyl groups. Polymers obtained by metallocene catalysts have structures in which ethylene is seemingly copolymerized due to 2,1 insertions or 1,3 insertions. The melting point of isotactic PP, as measured by differential scanning calorimeter (DSC), is approximately 165°C (while the equilibrium melting point is said to be 187.5°C). The melting point increases with increasing tacticity. Random copolymers typically contain ethylene at a concentration of 4.5 wt% or less in the copolymer. Ternary copolymers (terpolymers) obtained by copolymerizing ethylene with butene-1, as well as binary copolymers of propylene and butene-1 (without ethylene), exist and are available. Randomness does not necessarily mean statistically random. The distribution (randomness) of ethylene in the polypropylene main chain differs depending on the type of catalyst. The ethylene content is not necessarily the same in all molecular weight fractions; the ethylene content differs between low molecular weight chains and high molecular weight chains. In other words, there is a distribution of ethylene content (copolymer composition distribution). Polymers obtained using metallocene catalysts have a narrower and more uniform copolymer composition distribution than those obtained using solid catalysts. Random copolymers have lower crystallinity, are transparent, and are tougher and more flexible than homopolymers. The higher the content of a comonomer (the copolymerized monomer is mainly ethylene), the lower the melting point. A block copolymer is also called an impact copolymer or a heterophasic copolymer. This refers to a composition containing an ethylene-propylene polymer obtained by copolymerizing ethylene in a subsequent reaction tank after polymerization of a homopolymer. A block copolymer has a compatible structure (sea-island structure) in which "islands" of ethylene-propylene polymer are dispersed in the "sea" of homopolymer. This sea-island structure can be controlled by the ethylene content and molecular weight of the ethylene-propylene polymer and the molecular weight of the homopolymer. Unless otherwise specified, the term "block" in polypropylene does not refer to a conventional block copolymer. That is, it does not mean that homopolypropylene chains and ethylene-propylene copolymer chains are chemically bonded. A block copolymer in which the content of ethylene-propylene polymer is increased to 40 wt% to 50 wt% or even higher is sometimes referred to as reactor-made TPO, reactor TPO, or simply TPO. Block copolymers are superior to homopolymers in impact resistance, and inferior to homopolymers in transparency. As mentioned above, examples of PP include polypropylene, ethylene-polypropylene copolymer, propylene·1-butene·ethylene copolymer, propylene·1-hexene copolymer, propylene·1-hexene·ethylene copolymer, and propylene·4(or 5)-methyl-1,4-hexadiene copolymer. Isotactic PP and syndiotactic PP are crystalline resins. The crystal structure of isotactic PP, which is based on 3 / 1 helical chains, can take crystal forms such as α-crystal, β-crystal and γ-crystal, among which α-crystal is the dominant crystal structure. The crystal structure of syndiotactic PP is an orthorhombic crystal based on an 8 / 1 helical chain.

[0186] These PPs are used as the molding material of the present invention. In addition to being used alone as described above, they may also be mixed and used as a blend polymer for the purpose of imparting desired properties. The blend polymer may be produced either at the pelletization step, or by mixing the respective materials in a hopper during injection molding and blending at the metering step in the heating cylinder of an injection molding machine. This is called "mold blending".

[0187] (Masterbatch of foaming agent for PP) The PP pellet form mentioned above is also used to support the foaming agent powder. In the manufacture of the foaming agent, the PP powder and the foaming agent powder can be mixed together, solidified using a varnish such as maleic acid-modified PP in a process similar to H processing, and then pelletized (supported around the PP pellets). The principle of the H process is as follows: A Teflon-coated frying pan is heated to approximately 80°C, into which PP pellets are placed. For example, 20 wt% of baking soda powder is added to the PP pellets. While stirring to ensure that the pellets and foaming agent are uniformly mixed, a maleic acid-modified PP solution is sprayed onto the surface. The solvent in the maleic acid-modified PP solution evaporates, and as a result, the baking soda and maleic acid-modified PP are supported on the surface of the PP pellets, with the baking soda acting as a binder (for example, acting as an adhesive). After sufficient evaporation of the solvent, the pellets are removed and can be used as a master batch of foaming agent with 20 wt% baking soda supported. If the pellets are stuck together, they are sieved to standardize the particle size. Crushing may also be performed as needed.

[0188] Masterbatches of foaming agents for PP (polypropylene) manufactured by foaming agent manufacturers such as Eiwa Kasei, Sankyo Kasei, and Otsuka Chemical use the aforementioned inorganic and organic foaming agents and PE (polyethylene) compatible with PP as carrier resin and base resin to produce and market masterbatches of foaming agents for PP {for example, Polyslene EE207 (product name) sold by Eiwa Kasei}. When a master batch of foaming agent from Eiwa Kasei was added to PP (Nobren AZ864), and the base resin of Polyslene EE207 (product name, grade) was modified to include 3.5 wt% PE, a phenomenon similar to a swirl mark (code number 2) appeared near the gate even in molded products without surface swirl marks (code number 3) using the GCP method described later. (Figure 1) A similar phenomenon resembling swirl marks occurred near the gate with the foaming agent Polyslene EE25C (product name, grade, base resin is PE) manufactured by Eiwa Kasei. FT-IR (infrared spectroscopy) revealed that this swirl mark-like phenomenon was caused by PE in the foaming agent master batch. When the raw ADCA powder (in powder form) is spread onto pellets using paraffin oil and foam molding is performed using GCP, the phenomenon indicated by reference numeral 2 near the gate as shown in Figure 1 does not occur. Reference numeral 1 in Figure 1 represents the gate.

[0189] For reference, Figure 3 shows that swirl marks are present across the entire surface of foamed molded material (transparent ABS) without GCP (Ground Control Panel).

[0190] As a means of solving this problem, the inventor considered using a PP compatible with the PP to be foamed as the base resin for the foaming agent master batch. Even when using single-screw or multi-screw extruders, kneaders, etc., PP has a melting temperature that is more than 20°C higher than PE, so in these devices, the foaming agent to be added is thermally decomposed during the melt-mixing stage, and the function of the foaming agent master batch {amount of foaming gas generated per unit (for example, per 100 grams of foaming agent master batch)} decreases. As a means of solving this problem, we came up with the idea of ​​heating the PP pellets to be foamed on a plate and loading the foaming agent (e.g., ADCA, baking soda, etc.) onto the surface of the PP pellets while stirring paraffin oil, stearic acid, a volatile solvent, and foaming agent powder. When using this foaming agent master batch, since there is no PE present, there is no problem of silver formation near the gate caused by PE, as shown in Figures 1 and 2. Since Towa Chemical Co., Ltd. already possessed mass production technology for processing master batches of colorants, they prototyped a master batch of foaming agent for PP, using PP, which is compatible with PP, as the base resin, and containing 10 wt% each of ADCA and baking soda as the foaming agents.

[0191] The inventor used a Henschel mixer (trade name) and added 90 parts PP pellets to ADCA powder. Ten parts of the dart and five parts of Multi-Primer EXC-3000 as a binder (it can be added from the beginning, or added while spraying or dripping) were added, and while stirring, the mixer temperature was gradually raised from room temperature to 60°C to evaporate the solvent contained in Multi-Primer EXC-3000, confirming that it is possible to manufacture a foaming agent for PP (PP compatible with and / or compatible with PP) with ADCA supported around the PP. In addition to ADCA, it is also possible to manufacture it using baking soda or potassium bicarbonate. Similarly, emulsion and suspension type primers with maleic acid-modified resin as the main component can also be used as multiprimers (see Example 18).

[0192] A master batch of foaming agent containing ADCA was produced by mixing 70 wt% PP pellets, 20 wt% ADCA powder, and 10 wt% maleic acid-modified PP (ARROWBASE DB-4010 manufactured by Unitika Ltd., with emulsion properties), heating the mixture to approximately 80°C, and evaporating it to dryness (evaporating the water and other solvents in the emulsion). We also confirmed that the product can be manufactured using powdered sodium bicarbonate instead of ADCA. Furthermore, we confirmed that master batches can be produced similarly using sodium dihydrogen citrate as a foaming agent.

[0193] Besides baking soda, alkali metal salts of bicarbonate, microballoons and hollow fiber balls found in foaming agents sold under the brand name Advancel can also be used as foaming agents (master batches) in this method, as they are supported on the surface of resin pellets. Hardlen NZ-1015 (emulsion type, aqueous type), sold by Toyobo Co., Ltd., is commercially available and can be used even with a maleic acid modification amount (dissolved solids content is approximately 30 wt%). Maleic acid modified PP {PMA H1100P, PMA-F6 (product name) is in powder form; ADCA:PMA H1100P or PMA-F6 can be mixed in a ratio of 7:2:1 and heated to about 100°C to melt these maleic acid modified PPs, and ADCA can be supported around PP pellets. Alternatively, maleic acid modified PP can be dissolved using an organic solvent (e.g., toluene, alcohol, ketone, etc.) and used. Maleic anhydride exists in many molecular structures depending on its functional group. When maleic acid-modified PP is used in the production of foaming agents for PP, it can be dissolved in a solvent to produce varnish, emulsion, or suspension. Emulsifiers (surfactants) are used in the production of emulsions and suspensions, but if the emulsifier has poor thermal stability, it can cause problems such as burning and discoloration of the foamed molded product. Either do not use emulsifiers, or use emulsifiers with good thermal stability (that do not decompose even when exposed to molding temperatures).

[0194] This method allows for the support of maleic acid-modified PE on PE pellets. This foaming agent masterbatch can also be used for PE.

[0195] By using AS powder or ABS powder, baking soda, and a small amount of water, along with the same method used to make konpeito (Japanese sugar candy), the resin intended for molding can be used as a foaming agent masterbatch for AS and ABS foam molding. The same simple method can be used for PS and HIPS. This method can also be used to produce colored masterbatches for PC (polycarbonate).

[0196] (Masterbatch of foaming agent for ABS) This describes a method for producing a foaming agent masterbatch for ABS. First, ABS is dissolved in a solvent, such as methyl ethyl ketone (MEK, 2-butanone, ethyl methyl ketone, n-butanone), to produce a doped cement. Next, ABS pellets are placed in a Henschel mixer, followed by the addition of a foaming agent powder (e.g., ADCA, baking soda, etc.). The doped cement is then sprayed while being heated to approximately 45°C. The doped cement is adjusted to a sprayable viscosity using MEK or other solvents, such as toluene, as needed. Once drying is complete, a foaming agent masterbatch is obtained, with the foaming agent supported around (on the surface of) the ABS pellets. Similarly, in the case of a foaming agent (e.g., monosodium dihydrogen citrate), a master batch of the foaming agent can be obtained by using the foaming agent (in powder form) instead of the foaming agent and supporting it in the same manner. For example, urea is a substance that lowers the decomposition temperature of foaming agents such as ADCA. If urea is also supported by a similar method, a master batch of foaming agents can be obtained. Although an ABS-doped cement was used as the binder for support, the Repelle S#1100 in Example 6 is an acrylic paint, and its main component, styrene-modified acrylic resin, is compatible with ABS, HIPS, and m-PPO(E). Therefore, the varnish used in the manufacture of Repelle S#1100 (product name) {for example, DIC Corporation's styrene-modified acrylic resin, Acrydic M-1156 (product name)} can also be used as a substitute for the ABS-doped cement. AS (which is compatible with ABS) can also be used instead of ABS. Of course, emulsion-type styrene-modified acrylic resins can also be used instead of solvent-type resins.

[0197] For PS, HIPS, and m-PPO(E), doped cement containing HIPS and / or PS can be used instead of ABS. For PC, either PC or ABS doped cement compatible with PC can be used. Naturally, emulsion-type varnishes can also be used, as can the aforementioned doped cements used as emulsions. Foaming agent master batches for ABS using styrene-modified acrylic resin can be used for PC. In the case of PC, when sodium bicarbonate or ADCA is used as the blowing agent, foam-molded articles with smooth surfaces can be obtained by the GCP apparatus of the present invention, but the physical properties are significantly reduced due to the blowing agent. Effective blowing agents for foam molding of PC include a method of introducing a vaporizable liquid such as ethanol into a molten resin, vaporizing the liquid, and imparting foamability using ethanol vapor, or a method of adding dry ice into a molten resin (in the case of an injection molding machine, a hole is opened in the middle of a heating cylinder to add an optimal amount of the dry ice into the molten resin), allowing the dry ice to sublimate, and vaporizing carbon dioxide in PC to impart foamability. This method can also be implemented for other thermoplastic resins. In this case, finer foam cells can be formed when a cell nucleating agent is used.

[0198] As described above, by supporting the blowing agent, cell nucleating agent, and foaming auxiliary agent on individual pellets respectively and preparing separate masterbatches, the respective masterbatches can be mixed with pellets in an optimal formulation before molding, so that the formulation can be easily changed, and an optimal foaming state can be easily achieved. For the carrier resin used in the preparation of masterbatches for HIPS, ABS, and HIPS-modified PPO(E), for example, ABS has a structure in which butadiene rubber grafted with acrylonitrile in the AS matrix phase exists as dispersed domains. Although the grafted butadiene rubber may be used, AS which forms the matrix phase is employed. PS may be used for HIPS and modified PPO(E).

[0199] In the present invention, the production method of the blowing agent uses pellets or powder of the resin to be foamed (in the case of PP, powder obtained during production is also acceptable), and the reduction in physical properties can be minimized and avoided by using the same type of resin.

[0200] (Suitability for Coating) For a PP molded article in which swirl marks caused by PE shown in said FIGS. 1 and 2 have occurred, first a primer is applied , and after primer treatment with Multi Primer EXC-3000 (trade name, product number) manufactured by Musashi Paint Co., Ltd. used in Example 6, the top coating is EC-GPX79- manufacured by Musashi Paint Co., Ltd. Kohaiurec Silver (mixing ratio of base agent to hardener is 10:1) (product name, product number) paint The molded product was painted. The product was then subjected to a salt spray test in accordance with the Japanese Industrial Standard (JIS) K5600-7-1. When the salt spray test (SST) was performed for 240 hours, PE appeared near the area where it had surfaced. Blisters (swelling) have formed.

[0201] When a master batch of foaming agent containing 10 wt% foaming agent, with PP as the base resin and ADCA as the foaming agent, was used, the coating suitability (SST) was similarly evaluated. As it did not contain PE, no blistering occurred, and good adhesion of the coating was obtained. When baking soda is used as the foaming agent and PP is used as the base resin, no defects near the gate caused by PE have been observed. When the same painting process was followed and a coating adhesion test (SST) was performed, blistering occurred throughout the entire surface, resulting in poor coating suitability. Detailed observation of the surface of the foamed molded product revealed foaming agent residue (unreacted baking soda and foaming residue sodium carbonate). Believing that this foaming residue was the cause of the blistering, the foamed molded product was immersed in 1 wt% acetic acid solution for 10 minutes before painting, rinsed with water, and dried to remove the foaming residue. When painted after this process, no blistering occurred in the coating, and good coating adhesion was obtained.

[0202] (Removal of foaming residue) It has been confirmed that removing (dissolving and removing) foam residue from the surface of molded products made using bicarbonates such as baking soda by immersing them in an acidic solution or spraying an acidic solution onto the surface of the molded product to dissolve the alkali metal carbonates and bicarbonates present on the surface, and then applying paint, does not cause blistering or peeling of the paint film. The acids used in pickling include strong acids such as hydrochloric acid, sulfuric acid, nitric acid, and chromic acid, as well as weak acids such as acetic acid, citric acid, malic acid, and sulfamic acid. Both inorganic and organic acids can be used. A lower hydrogen ion concentration (pH) in the pickling solution improves the dissolution (removal from the molded product surface) of the carbonate. However, a low pH creates a poor working environment. Therefore, a pH of 7 or lower is suitable for good chemical reactions (chemical reactions and neutralization reactions between the foam residue in the molded product and the acid). Increasing the temperature of the solution in the pickling bath further enhances the removal effect. Furthermore, a higher temperature of the cleaning solution improves the removal of foam residue. The above-mentioned acids can be used individually or as a mixture.

[0203] (Paint suitability of other foaming agents) When the commercially available foaming agent Advancel was used with TSOP (a PP-based resin used by Toyota Motor Corporation for resin molded parts in automobiles) No. 6, paint adhesion tests confirmed that, similar to the case with baking soda, blistering occurred and the adhesion of the paint film decreased. A similar decrease in paint film adhesion was observed with Fineblow (product name). It is presumed that the cause of Fineblow's problems is the use of baking soda as a foaming agent.

[0204] (GCP) GCP is an effective method for eliminating swirl marks that occur on the surface during foam molding. It is a process in which the molding space inside a sealed mold, as shown in Figures 10 and 11, is pressurized to a pressure greater than atmospheric pressure using, for example, air, nitrogen gas, carbon dioxide, hydrocarbons such as methane and ethane, or noble gases such as hydrogen, helium, and argon. This process of pressurizing the molding space is called GCP. The act of pressurizing the molding space is also called "compressing with air," and the gas inside the molding space (L1, L2, L3) is also called compressed air. The process of pressurizing the molding space, filling it with foamed resin to impart foaming properties, and then exhausting the compressed air is also considered GCP. Compressed air is an effective means of suppressing surface foaming and obtaining foamed molded products with a clean appearance without swirl marks, but it is a troublesome element in resin filling. The force of filling the molded space with resin pushes it up to the parting line (PL) to improve surface transferability, but if the resin filling speed is too fast, if the mold surface is glossy, if the depth of the textured surface is too shallow, if the resin temperature is too high, if the viscosity of the molten resin filling the molded space is low, or if the mold temperature is high, the gas in the GCP (Ground Pressure Packing) will be trapped. The trapped gas in the GCP has nowhere to escape and as a result remains on the molded surface, resulting in sink marks (in this case, called raindrops). To solve this problem, after exhausting the GCP, the mold is opened (retracted, recessed, recessed, mold-back, core-back) to rapidly release the GCP gas trapped on the surface of the molded product to the outside. If necessary, vacuuming is performed as shown in Figure 49. While it was mentioned that a gas vent of about 0.05 mm should be provided in the parting line (PL) of the mold, sintered metal (part number 149 on the right side of Figure 50) may also be used in the PL. In this case, since sintered metal has low strength, a portion of it should be sandwiched with a material of higher strength (hardness). The parting line can also be made multi-layered (part number 150 on the left side of the PL in Figure 50) to allow for smoother gas exhaust. (Figure 51) As shown in Figure 51, a gas vent (reference number 153) may be provided in the center of the mold. In this case, the molten resin covers the gas vent 153, so the gas exhaust effect is low. Exhausting from the parting line is effective. The molds shown in Figures 10 and 11 have an insert structure (reference number 23, etc.), so compressed air can enter the molding space, and have the same effect as reference number 153. Partial exhaust is possible, so it is absolutely necessary to install a gas circuit (for example, Figure 39, etc.) in the parting line.

[0205] (GCP principles) The principle of GCP will be explained using the carbonated water shown in Figure 6. Carbonated water is made by dissolving carbon dioxide gas under pressure in water. The stopper at the top (labeled 5) is closed, and the pressure applied to part labeled 6 (labeled 6) pressurizes and dissolves the carbon dioxide gas in part labeled 7 (the solvent water). The carbonated water inside (labeled 7) is in a supersaturated state under atmospheric pressure. When stopper 5 is opened, the pressure at symbol 6 becomes equal to atmospheric pressure, causing any excess dissolved carbon dioxide to turn into gas and fizz. Symbol 8 is the container. If we were to replace carbonated water with the heating cylinder of an injection molding machine, then the stopper labeled 5 would be a shut-off nozzle. The container (bottle, PET bottle) labeled 8 would be the heating cylinder. When the foaming agent and the resin pellets to be molded are mixed in the hopper and heated and melted, the foaming agent decomposes thermally, generating a foaming gas. If a back pressure above a certain pressure is applied during the plasticization and metering stages, the foaming gas will be finely dispersed or dissolved under pressure in the molten resin inside the heating cylinder. Typical examples of foaming gases include nitrogen gas, carbon monoxide, carbon dioxide, water vapor, and vapors of organic solvents such as alcohol. Nitrogen gas has low affinity (solubility) with thermoplastic resins, so it mostly disperses finely within the resin. Carbon monoxide and carbon dioxide have high affinity, so they mostly dissolve in the resin. Water vapor exhibits solubility that is roughly intermediate between nitrogen gas and carbon dioxide. Alcohol vapor has a very high affinity for resins, and using alcohol vapor as a foaming gas increases the fluidity of the molten resin. The foaming gas inside a heating cylinder is governed by Henry's Law and Boyle's Law. Henry's Law applies to gases with high affinity to molten resin, such as carbon dioxide, while Boyle's Law applies to gases with low affinity to molten resin, such as nitrogen.

[0206] (GCP molds) The principle of GCP will be explained using beer, which has the same carbon dioxide dissolved under pressure as the carbonated water mentioned above (Figures 7 and 8). Now, if we open the door (number 11) to the space partitioned by number 9 (number 10) and pour beer into a glass at the same pressure as atmospheric pressure {1 atmosphere (atom)}, foam (number 12) will form on top of the glass, as shown in Figure 7. Next, if we close the door (number 11) and pressurize the partitioned space (number 10) with air at 10 times atmospheric pressure (10 atmospheres) using a compressor or the like, and pour beer into a glass in that pressurized atmosphere, the beer will not foam because of the external pressure of 10 atmospheres (Figure 8). Next, when door 11 is opened and the pressure in space 10 is suddenly reduced from 10 atmospheres to 1 atmosphere, the carbon dioxide is dissolved under pressure. The supersaturated carbon dioxide follows Henry's Law, and as the external pressure decreases, the carbon dioxide trapped (dissolved) in the water is released into the beer. This is the principle of GCP. In the case of nitrogen, the foaming gas, whose volume has decreased due to the pressure of the compressed air, expands in volume when the external pressure (the GCP pressure, corresponding to the pressurized air inside the mold) is removed and the compressed air is released.

[0207] The specific methods for implementing this process in injection molding will be explained. The method for manufacturing foamed resin involves mixing the resin pellets to be molded (not limited to pellets; powder or bulk is also acceptable; the shape is not important as long as plasticization can be achieved in the heating cylinder of the molding machine) with the above-mentioned gas, liquid, or solid foaming agent in a desired ratio. {The ratio of foaming gas to the volume of the resin to be foamed should be between 25 vol% and 250 vol%. However, if the compressed air pressure is low, the force (pressure) that suppresses foaming is low, so it is not possible to add a large amount of foaming agent. On the other hand, if the compressed air pressure is high, a large amount of foaming gas can be dissolved under pressure and finely dispersed. When using air as the GCP, it should be around 2 MPa, similarly for nitrogen gas, and when using carbon dioxide gas, since it is easily liquefied, it is best to use a pressure slightly lower than the critical pressure at the temperature of that compressed air.} [In the case of liquid, it may also be impregnated into the resin to be foamed.] For example, if ABS is immersed in water and molded while impregnated with water, the water in the ABS will vaporize at the temperature inside the heating cylinder (the temperature of the heating cylinder, screw, and molten resin) and act as a foaming agent. Alternatively, silica gel can be impregnated with water and mixed with pellets. In the case of a gas, it will be plasticized and added to the molten resin to impart foaming properties to the heated and molten resin. Of course, liquid foaming agents can also be added to the heated and molten resin in the same way as gases to impart foaming properties to the heated and molten resin. In the case of a solid foaming agent, it is mixed with pellets and added to the hopper, but it can also be added by making a hole in a part of the heating cylinder. For example, solid carbon dioxide (dry ice (in this case there is no foaming residue, so it does not affect the adhesion of the coating)) can be added to the molten resin inside the heating cylinder and sublimated to impart foaming properties to the internally molten resin. Naturally, baking soda and chemical foaming agents such as ADCA can also be used in the same way as dry ice. The material is heated and melted to plasticize it. During this plasticization stage, the foaming agent vaporizes and undergoes thermal decomposition to generate foaming gas, which is then finely dispersed and dissolved in the molten resin heated and melted within the heating cylinder. To achieve fine dispersion, it is best to increase the pressure applied to the molten resin within the heating chamber. To achieve pressurized melting, it is generally necessary to increase the back pressure during plasticization and increase the screw rotation speed.A screw with a high-mixing design is preferable, and if necessary, using a screw with a damping mechanism will allow the foaming gas to disperse more easily in the molten resin, resulting in finer and more micronized foam cells within the resulting foamed molded product.

[0208] The properties of the foaming agent can be gaseous, liquid, or solid. For gaseous foaming agents, they are placed in a heating cylinder and dispersed by a screw, requiring a damaging device. For liquid and solid foaming agents, gas is generated at the molecular level (primarily vaporization in liquids and thermal decomposition in solids), which then condenses to form a foaming gas, so a damaging device is not necessary, although its presence is not problematic. In the case of solid foaming agents, they are mixed into the resin pellets as a master batch before plasticization, so a damaging device may be used, but is generally not. This section describes methods for finely dispersing foaming gas generated from a gaseous, liquid, or solid foaming agent in the molten resin within a heating cylinder. For plasticization, a screw with high mixing capabilities is preferable. Using a screw with a large L / D ratio and applying high back pressure while plasticizing (melt mixing) for a long time results in fine dispersion of foaming gases within the molten resin. When back pressure is increased in this way for plasticization (metering), the molten resin inside the heating cylinder leaks out from the nozzle tip due to the back pressure and the foaming pressure (of the plasticized and foamed resin inside the heating cylinder). To solve this problem, a shut-off nozzle is used by means of a spring-type air cylinder, hydraulic cylinder, or mechanical mechanism. Even after metering is complete, it is necessary to continue applying pressure to the molten resin inside the heating cylinder until the next injection to suppress foaming inside the heating cylinder and prevent foaming. This is called back pressure blocking (end back pressure). The shut-off nozzle here performs the same function as the plug indicated by reference numeral 5. There are also hot runners with a valve gate system that have the same function as a shut-off nozzle but are opened and closed by hydraulic, pneumatic, or other mechanical means (such as actuators).

[0209] There are two types of mold structures for GCP: an ejector box type (Figure 10) and a type that seals the ejector pin with a load-operated O-ring or the like (Figure 11). The respective structures will be explained using Figures 10 and 11. First, let's explain the ejector box type (Figure 10). In Figure 10, reference numeral 16 is the spool bush, reference numeral 17 is the mounting plate on the fixed side, reference numeral 18 is the mold plate that houses the fixed side insert, reference numeral 19 is the fixed side insert, and reference numeral 20 is the mating surface of the fixed side insert where gas enters and exits (gas passes through easily because it is a mating surface). Reference numeral 21 is the cavity (molding space) where molten resin is filled, reference numeral 22 is the mold plate that houses the movable side insert, reference numeral 23 is the movable side insert, reference numeral 24 is the ejector pin, reference numeral 25 is the ejector plate (top) that fixes the ejector pin, reference numeral 26 is the ejector plate (bottom) that fixes the ejector pin, reference numeral 27 is the spacer block with a sealing function, support pillar, reference numeral 28 is the mounting plate on the movable side, and reference numeral 29 is the hole for the ejector rod. Reference numeral 30 indicates the mating surface of the movable insert, and reference numeral 20 indicates the mating surface of the fixed insert, through which gas enters and exits (gas can easily pass through because they are mating surfaces).

[0210] To make a mold a sealing mold, O-rings must be placed in each gap (matting surface). Part number 31 is the O-ring placed in the spool bush, part number 32 is the O-ring placed in the fixed-side mounting plate, and part number 33 is the O-ring placed in the parting. The cross-section of these O-rings is not limited to circular; it can be triangular (△), square (□), or polygonal. V-shaped and U-shaped ones are also acceptable. The inserts that form the cavity on the movable side are divided into smaller inserts (part number 23), smaller inserts (not shown), etc., and these are fixed to the mold plate (part number 22) with bolts (not shown). For example, even if compressed air is used to pressurize the cavity of the GCP (compressed gas) inlet and outlet circuits (both are the same circuit) provided in the parting, gas will leak out through the gaps in the inserts and the gaps in the ejector pins. Therefore, in order to seal the gas leaks from the gaps in the inserts and the gaps in the ejector pins, a spacer block (part number 27) is made into the shape of the Japanese katakana character "ロ" and encloses the entire ejector mechanism (part number 34). This mold structure is called an ejector box. In this ejector box mold structure, part number 35 is an O-ring placed between part number 22 and part number 27, which is an ejector box-shaped spacer block, and part number 36 is an O-ring placed around the hole in the ejector rod to seal when the ejector plate (part number 34 ejector mechanism) is retracted.

[0211] In Figure 10, the parting plate and ejector plate are movable, so measures must be taken to prevent the O-rings (part numbers 33 and 36) from coming loose, such as fitting them into the dovetail groove (part number 39). In Figure 12, part number 38 indicates either O-ring 33 or 36. (Figure 12) In Figure 11, there is no need to have an ejector box (referring to the space sealed by part number 27, which is L1 in Figure 13), so part number 37 is a spacer block of a normal shape (simply a rectangular block shape).

[0212] In the case of Figure 10, the ejector mechanism (reference number 34) is enclosed by reference number 27, and because the resulting space (volume compressed with air, etc.) is large, a large amount of gas is required for the compressed air. Even if the gas is air, it is not economical, but if nitrogen gas, carbon dioxide, etc. are used for the compressed air, a large amount is used and consumed, making it impractical. When using expensive gases such as nitrogen or carbon dioxide as compressed air, they may be recovered and reused later, but caution is necessary because monomers from the resin may enter and cause contamination, leading to problems with the pressurization equipment.

[0213] If the ejector pin is sealed using the load-type O-ring (packing, seal) with a U-shaped groove as shown in Figures 24, 25, 26, 27, and 28 of the present invention, instead of the ejector box indicated by reference numeral 27, the amount of gas required for pressurized air can be reduced, thus solving the aforementioned economic problem. Effective seals for the ejector pins include the U-shaped packing shown in Figure 27, and load-type O-rings (e.g., OmniSeal (product name), Bariseal (product name)) which contain a U-shaped spring (part number 85) as shown in Figures 24, 25, and 26 (inserted for the purpose of applying load, tightening inward). Instead of the U-shaped spring (part number 85), a standard-shaped spring as shown in Figure 29 or a commercially available O-ring as shown in Figure 30 may be used. The materials for the U-shaped packing and load-type O-rings are preferably Teflon (product name), Teflon with approximately 10 wt% graphite added to enhance sliding properties, Turcon (product name), or silicone rubber, but urethane rubber, nitrile rubber, etc., are also acceptable. As shown in Figure 36, a single-pressure seal (tightened inward) provides strong sealing force and can maintain sufficient airtightness even at low pressure. The O-ring labeled 42 is used by fitting it into the ejector pin and fixing it in place, so it is fitted between the plate labeled 40 (upper) and the plate labeled 41 (lower). An O-ring (labeled 38) for sealing is placed between the plate labeled 40 (upper) and the mold plate that houses the movable insert labeled 22. In Figure 11, an O-ring is also placed between the plate labeled 40 (upper) and the plate labeled 41 (lower) as a precaution, but it is not necessary because there is a load-type O-ring labeled 42. In the case of an inclined core, sealing is only required when the mold is closed (PLs are aligned), so the lower side can be made cylindrical and sealed with a load-type O-ring as shown in Figures 24 to 28. Alternatively, a shape can be created at the front of the inclined core, and an O-ring can be placed there to seal when the mold is closed. The mold structure of GCP only needs to perform a sealing function when the mold is closed, and in the case of a slide core using an angular pin, the O-ring (reference number 33) placed at PL is placed inside (provided there). The same applies to hydraulic, pneumatic, and mechanical slide cores. If a seal is required on the parting surface of the slide core, seal it in the same manner as the parting surface.

[0214] In Figure 36, part number 112 is a single-sided load-bearing seal, referred to as an "L-shaped seal." The material used is PTFE or Teflon (product name), which has high sliding properties, or a material made by mixing Teflon with graphite at a ratio of 5 to 25 wt%, but other materials are also acceptable. Part number 113 uses a commercially available O-ring {material is NBR (acrylonitrile butadiene rubber, nitrile rubber)} to load part number 112, but a coil spring as exemplified in Figure 29 is also acceptable. The L-shaped seal is housed in housing 114, which is formed by reference numbers 40 and 41. The detailed shape of reference number 114 is described in detail in Figure 48 (Table 15). In Table 15, EP is an abbreviation for ejector pin, and EP diameter (symbol d) and h9 (fit tolerance) are indicated. The K seal number is the management number for the L-shaped seal suitable for each ejector pin, with D (diameter) +0.05, L (depth) +0.2, and a fit tolerance of S (clearance) of approximately H7 / f8, c (C-shape of the opening) 0.3, and r (R-shape of the base) a maximum of 0.4 (0.4 Max). The notes section contains precautions to take when inserting the ejector pin into the K seal. These symbols in Figure 48 correspond (are associated) with Figure 36.

[0215] Figure 11 shows that the ejector pin is sealed with a load-type O-ring using parts number 25 and 26, sandwiching part number 42. Figure 37 shows that the ejector pin 24 is sealed in the same way by sandwiching part number 42 using a sealing (retaining) block (upper) with part number 116 and a sealing (retaining) block (lower) with part number 117. This method differs from Figure 11 and shows a method for sealing one ejector pin (inclined pin, inclined slide) each. Part number 115 is an O-ring that serves the same function as the O-rings of part number 118 or 119. In Figure 37, for example, it is installed at the bottom of the movable side mold plate, and the plate, bolts, etc. that fix part number 115 are omitted and not shown.

[0216] (GCP process) The GCP apparatus is essentially the same for molds sealed with an ejector box structure and molds sealed with ejector pins using load-type O-rings, etc. (In molds sealed with load-type O-rings, a sub-tank 55 is provided). (1) Close the mold, (2) Touch the nozzle, (3) Inject compressed gas into the mold using a compressor, etc. (compressed gas = sometimes called GCP), (4) Fill the cavity with foamable resin (molten resin with foaming properties imparted using physical foaming agents or chemical foaming agents) while the air is still compressed. The timing of starting the filling is determined by monitoring the pressure of the gas injected into L2 and confirming that the desired pressure has been reached before injecting (filling) can be started. (5) During or after filling, the compressed gas is exhausted or collected in a separately provided container, (6) Once the foamable resin has cooled in the mold, open the mold and remove it. The method of obtaining foamed molded products with a clean appearance without swirl marks on the surface using this technique is called the GCP method, and the process is called the GCP process. In this invention, GCP refers to the series of processes described above {closing the mold → injecting gas into the mold → filling (injecting) the foaming resin → exhausting the gas...}, and the act of introducing gas into the mold (into L1, L2, L3, etc.) to suppress foaming is referred to as "compressing the gas, performing GCP, performing GCP, pressurizing GCP, applying GCP," etc. "Compressed gas" can also refer to the gas introduced into the mold (into L1, L2, L3, etc.).

[0217] (GCP device) In Figure 13, L1 is the space containing the ejector mechanism 34, enclosed by reference numeral 27. In Figure 14, it is the space at the bottom of the movable insert (a sealed space enclosed by reference numerals 33, 118, 119, and 42). In both Figures 13 and 14, L2 is the cavity space (reference numeral 21). L3 is the space at the bottom of the fixed insert, sealed by reference numerals 32 and 33. (Figures 13, 14) When reference numerals 40 and 41 in Figure 14 are used, O-rings corresponding to reference numerals 118 and 119 must be placed, similar to the movable side. The roles of L1 and L3 are as follows: When molten resin is filled into L2, the compressed air is an effective means of suppressing foaming, but it can also hinder the filling of molten resin into L2, causing problems such as short molding, discoloration, and burning. To solve this problem, a space exists between L1 and L3. When molten resin is filled into L2, the gas inside L2 is pushed out into this space, preventing the pressure inside L2 from becoming abnormally high, thus eliminating problems such as short molding, discoloration, and burning.

[0218] Figure 15 shows the GCP device, where reference numeral 43 is an injection valve (reference numeral 46) that injects (compressed air) compressed to above atmospheric pressure into the mold at the timing described above, as compressed by an air compressor. Reference numeral 51 is an exhaust valve that exhausts the compressed air that has been introduced into the mold. Anticipating troubles such as power outages, the inventor has selected a normally closed injection valve 46 and a normally open exhaust valve 51 for safety reasons. With this combination, in the event of a power outage, the compressed air being sent into the mold will stop immediately, and the compressed air that has been sent into the mold will be immediately exhausted, thus preventing accidents such as the mold opening due to the pressure of the compressed air inside the mold. The device in Figure 15 operates via a separate controller (not shown), or by incorporating the program of this controller into the molding machine's controller, based on their commands {such as compressed air inlet and outlet}. The GCP device in Figure 15 is a simple design with one injection valve and one exhaust valve, connected to spaces L1 through L3 by a flexible hose (reference number 52). In this case, injection and exhaust of spaces L1 through L3 are performed by this hose. Depending on the size and shape of the molded product, three of the devices shown in Figure 15 may be prepared and used. In some cases, even more devices may be used. First, we will explain the means of performing GCP using one of the devices shown in Figure 15. Multiple hoses 52 are connected to the manifold 49. The ends of the hoses 52 are connected to the L1 to L3 spaces of the mold shown in Figure 13 (mold with ejector box structure). In this case, when using one GCP device as shown in Figure 15, the inflow (injection) and outflow (exhaust) of compressed air into the L1 to L3 spaces are performed simultaneously. Reference numeral 44 indicates the circuit connecting reference numeral 43 and reference numeral 46 (usually a flexible hose is used; a steel pipe is also possible), reference numeral 48 indicates the part that connects to hose 52, and is generally a one-touch coupler (the inventor uses a male shape for the manifold and a female shape for the end of the hose. The mold is standardized to male, but this is not always the case). The arrow in reference numeral 53 indicates the direction of the compressed air flow, reference numeral 54 indicates that compressed air enters and leaves the mold using the same hose, and reference numeral 47 indicates that the compressed air is exhausted into the atmosphere.

[0219] In the mold shown in Figure 13, if three of the devices shown in Figure 15 are prepared and connected separately to spaces L1 to L3, for example, injection after the mold is closed can be performed simultaneously, while exhaust can be performed with a time delay. Using one of the devices shown in Figure 15 and connecting it to spaces L1 to L3 is called single-stage extraction (single-stage exhaust), while preparing three of the devices shown in Figure 13 and connecting them to spaces L1 to L3, and exhausting with a time delay, is called three-stage extraction (three-stage exhaust), and is effective for molded products with complex shapes. Exhausting L1 and L3 first, and then L2 with a slight delay, makes it easier to suppress (control) swirl marks. The GCP device in Figure 16 differs from the GCP device in Figure 15 in that it has a sub-tank indicated by reference numeral 55. This GCP device in Figure 16 has the function of transferring the gas inside the mold structure L2, which is sealed with a load-type O-ring or the like at the ejector pin shown in Figure 14, to this sub-tank (reference numeral 55), thereby preventing the pressure inside L2 from becoming abnormally high. In the cases of Figures 10 and 13, the ejector box L1 serves as this sub-tank, so it is not necessary. However, in the case of large molded products, the volume of the ejector box L1 increases, requiring more compressed gas and more time for the compressed air to be applied. As a result, the processing cost of the molded product increases, making it uneconomical. To solve this problem, sealing the ejector pin using part number 42 (using a load-type O-ring) reduces the amount of gas required for the compressed air and shortens the required time. However, when molten resin is filled into L2, there is little room for the compressed air in the cavity to escape, causing the pressure inside L2 to become abnormally high (rise), leading to short molding, discoloration, and burning. This problem can be solved by installing a sub-tank 55 in the GCP device. Figures 15 and 16 show a pressure gauge labeled 56. By visually monitoring the pressure and pressure increase status of the compressed air into spaces L1, L2, and L3, or by using other measuring devices, or by setting the injection to start when the compressed air reaches a preset pressure, the time from compressed air to injection can be shortened, virtually eliminating downtime (unnecessary time). This is expected to improve productivity compared to the mold structure in Figure 10. Furthermore, monitoring the pressure allows for monitoring for defects caused by insufficient compressed air pressure.

[0220] (Rapid exhaust valve) To expel the compressed air from inside the mold more quickly, a rapid exhaust valve can be installed in the mold to increase the exhaust speed of the compressed air, using the QEV2 series (product name) from CKD Corporation or the AQ series (product name) from SMC Corporation.

[0221] (Such as connecting the GCP device to the sealing mold) Figure 11 specifically shows the connection between the mold with the ejector pins sealed and the GCP device shown in Figure 16. Reference numeral 127 indicates a circuit installed in the mold that introduces compressed air into the L1 space, fills it with foamed resin, and exhausts the compressed air during the filling process and after the filling is complete. Reference numeral 126 indicates a circuit installed in the mold that introduces compressed air into the L2 space, fills it with foamed resin, and exhausts the compressed air during the filling process and after the filling is complete. Reference numeral 125 indicates a circuit installed in the mold that introduces compressed air into the L3 space, fills it with foamed resin, and exhausts the compressed air during the filling process and after the filling is complete. Reference numeral 128 indicates a one-touch coupler installed in each of these circuits.

[0222] Part numbers 118 and 119 are O-rings, and part number 120 is a one-touch coupler installed on the piping 121 from the compressor that guides the compressed air from the compressor 43, which supplies compressed air to the respective L1 to L3 spaces, to the GCP device. Part number 122 is a GCP device that controls the inflow and exhaust of compressed air to L3, part number 123 is a GCP device that controls the inflow and exhaust of compressed air to L2, and part number 124 is a GCP device that controls the inflow and exhaust of compressed air to L1. As described above, the inflow and outflow of compressed air to the L1 to L3 spaces in the mold are controlled by the injection molding machine or a separately provided controller. Figure 38 shows how the mold in Figure 11 can be connected to a GCP device, indicated by reference numerals 122 to 124, to enable multi-stage exhaust. However, unless the shape is complex, a single GCP device, indicated by reference numerals 122 to 124, can be used and connected to L1 to L3 and, for example, the coupler 48 attached to 123, to provide a single-stage exhaust. Of course, there is no problem using the GCP device shown in Figure 16 with the mold in Figure 10.

[0223] This section describes the means for allowing compressed air to enter and exit the L2 space (cavity). Figure 39 shows a front view of the fixed side parting surface. Reference numeral 129 is a groove carved outside the product shape. The inventor has specified a width of approximately 8 mm and a depth of approximately 3 mm, but the shape is not a major concern as long as it does not create significant resistance to the entry and exit of compressed air. Reference numeral 130 is a gas vent connected to reference numeral 129. The inventor has specified a width of approximately 5 mm and a depth of approximately 1 mm, but the shape is not a major concern as long as it does not create significant resistance to the entry and exit of compressed air. Reference numeral 131 is also a gas vent, but since it is directly connected to the product shape (molding space), it is shaped so that compressed air can easily pass through, but molten resin cannot. In the case of styrene-based resins such as ABS, which have relatively high viscosity, the inventor specifies a width of approximately 5 mm and a depth of approximately 0.05 mm to 0.1 mm. For resins with low viscosity, such as PP, the inventor specifies a width of 5 mm and a depth of approximately 0.02 mm to 0.05 mm. The optimal depth for the gas vent (reference number 131) is such that compressed air can enter and exit without resistance, but without forming burrs. In the foam molding of the present invention, resin holding pressure is not used, or if it is used, it is at a low pressure for a short time (for example, about 30% of the maximum injection pressure, with a pressurization time of about 0.5 to 2 seconds). Furthermore, the amount of foamable resin filled into the molding space by the primary filling speed and pressure is equal to or less than the volume of the molding space, so even if a gas vent is provided, burr formation is not significant.

[0224] Figure 40 is a side view of Figure 39, showing the connection between the compressed air circuit 128 to L2 and the opened compressed air passage in the mold labeled 132. Figure 41 shows the L1 space in Figure 11, and the L3 space in Figures 10 and 11. Figure 41 will be explained as the L1 space in Figure 11. Reference numeral 132 indicates the part where reference numeral 40 is in contact with the bottom of reference numeral 23. Reference numeral 134 is a groove through which compressed air passes, and reference numerals 133 and 134 are holes made in reference numeral 40 (compared to reference numeral 127, which is a compressed air circuit) that is a circuit for the inlet and outlet of compressed air. The mating surface 30 of part number 23 is also processed to have the same shape as part numbers 131 and 130 to provide a sufficient gas vent {when the foamed resin in the molding space is filled, the pressure (force) will smoothly push out the compressed air, eliminating problems such as short molding, discoloration, and burning}. This gas vent is connected to part number 134.

[0225] Figures 38, 39, 40, and 41 are connected to L1 through L3 in Figure 10 or Figure 11, indicating that when compressed air is used by the compressor 43, it can enter and exit without resistance. By connecting nitrogen gas to the intake of the compressor 43, nitrogen gas control can be implemented.

[0226] Figures 39 and 40 show that compressed air is supplied to the molding space by installing a gas circuit on the mating surface of the parting line, allowing compressed air to enter (compressed) and exit (exhausted) through the gap. There is also a method of supplying and exhausting compressed air by installing it on the non-decorative part of the molded product (mainly the working side where the ejector pin marks are left), but supplying and exhausting compressed air from the parting line is smoother. For reference, Figure 50 shows Figure 51, which shows the compressed air and exhaust circuit installed in the center of the product, and the explanation is as described above.

[0227] (Amotec, GCP for nitrogen gas) The apparatus in Figure 16 is equipped with a check valve 58. The function of this check valve is that, for example, if the space is pre-compressed to about 1 MPa using inexpensive air, and then compressed to about 2 MPa with nitrogen gas from a separately installed device and circuit into the L2 space, the oxygen concentration in the L2 space will decrease. Therefore, discoloration and burning can be reduced in GCPs with inert gases or gases with reduced oxygen concentration. In the GCP method described above, where carbon dioxide is used instead of nitrogen, carbon dioxide dissolves from the molten leading edge of the foamed resin, improving transferability to the mold and inducing the molten resin. In composite materials containing glass fibers, this method suppresses the floating of glass fibers, resulting in a cleaner appearance. The check valve 58 is installed to prevent nitrogen gas, carbon dioxide gas, etc., which will be applied to the compressor later, from entering L2, as it is dangerous to apply pressure exceeding the compressor's pressure rating to L2. Naturally, the GCP devices in Figures 15 and 16 have safety valves (not shown) attached to the manifold 49 for safety. The device in Figure 16 can be used with either the mold in Figure 13 or Figure 14. The method of connecting one GCP device in Figure 15 to the mold in Figure 13 and the method of connecting three GCP devices in Figure 15 have been explained, but the mold in Figure 14 and the GCP device in Figure 16 can similarly perform single-stage exhaust or multi-stage (e.g., 3-stage) exhaust with one or three units.

[0228] (Control of injection molding machine) Figures 15 and 16 show the details of the GCP apparatus control. First, the foaming resin manufacturing method, or in other words, the means of imparting foaming properties to the molten resin in the heating cylinder of the injection molding machine, is described in detail. Initially, solid foaming agents such as ADCA and, in the case of powders such as baking soda, are used by spreading them onto pellets. For example, resin pellets to be foamed are placed in a tumbler, the required amount of foaming agent is added, and a small amount of paraffin oil, which acts as a spreading agent, is added to spread the foaming agent powder around the resin pellets. This is placed in a hopper and sent into the heating cylinder. When heated and melted, the foaming agent decomposes thermally, generating foaming gas. This foaming gas is then finely dispersed into the molten resin inside the heating cylinder by the force of the screw's rotation and the back pressure acting on the molten resin. Because the pressure on the molten resin is high, pressurized melting also occurs. Since foaming agents are difficult to handle in powder form, when the foaming agent is made into pellets, the pellets of the resin to be foamed are simply mixed in or supported. The foaming agent pellets (master batch) and the pellets of the resin to be molded are mixed in a tumbler and then put into a hopper in the same way to produce the foamed resin.

[0229] (screw) To dissolve and finely disperse foaming gas under pressure in the molten resin inside the heating cylinder, high mixing is required, and the compression ratio (CR) should be around 2.4 to 4, and in the case of engineering plastics, it may be 4 or higher. The effective length {L (total length of screw) / D (diameter of screw)} should be 15 or more, preferably 18 or more, as a larger L / D (value obtained by dividing L by D) results in high mixing, which is useful for dissolving and finely dispersing foaming gas under pressure in the molten resin. The screw is divided into a supply section, a compression section, and a metering section. In general solid molding, the supply section is about 1 / 2 the length, the compression section is about 1 / 4, and the metering section is about 1 / 4 the length. However, in foam molding, the compression section is made as long as possible (1 / 4) to allow sufficient pressurized dissolution and fine dispersion of the foaming gas. Lengthening the compression section increases the L / D ratio, which allows for a longer compression time of the molten resin. In addition, measures such as making the screw flights shallower to achieve high mixing or using double flights are taken.

[0230] As is evident from the pressure in the GCP, while external pressure can contain the foaming gas, a higher back pressure during plasticization (metering) allows for more uniform and finer dissolution and dispersion of the foaming gas within the molten resin in the heating cylinder. In this invention, the back pressure varies depending on the resin and the type of foaming agent used, but generally, a back pressure of 5 MPa or higher is sufficient during metering (plasticization to dissolve and finely disperse the foaming gas within the resin). The inventor sets the back pressure slightly lower than the pressure at which suds drip from the shut-off nozzle during metering, aiming for the highest possible back pressure. If the back pressure is cut off after metering is complete, foaming (pre-foaming) will occur within the heating cylinder, so it is necessary to maintain the back pressure {end back pressure (EBP)} until injection begins. In this case, the EBP pressure should be around 5 MPa. In this embodiment, a screw design with a CR of approximately 3 and an L / D of 18 was used. For a φ60 full-flight screw, the following are examples of specifications: the length of the flight section is 1,560 mm, the length of the feed section is 480 mm, the length of the compression section is 540 mm, the length of the metering section is 540 mm, the CR is 3, the groove depth of the feed selection is 8.3 mm, the groove depth of the metering selection is 2.5 mm, the width of the flight is 6 mm, and the angle of the screw tip is approximately 90° to 30°.

[0231] In the case of liquid foaming agents such as ethanol or aqueous solutions of bicarbonates like sodium bicarbonate, a hole is made in the heating cylinder, and an inlet with a valve or an inlet embedded with sintered metal is provided. Simultaneously with the start of metering, or with a slight delay, the liquid is injected into the resin heated and molten in the heating cylinder. The temperature (thermal energy) of the heating cylinder and the temperature (thermal energy) of the molten resin vaporizes the liquid, evaporates to dryness, and thermally decomposes to generate a foaming gas, imparting foaming properties to the molten resin in the heating cylinder. Liquid injection can be stopped before metering is complete, simultaneously with metering completion, or after a certain period of time has elapsed after metering completion. If necessary, liquid injection may also be temporarily stopped during metering. The method for imparting foaming properties by introducing gases such as MuCell or AmoTec into the heating cylinder and dispersing them in the molten resin is substantially the same as in the case of liquids.

[0232] The program inside the injection molding machine actually includes the following: (1) Starting from zero when metering begins; (2) Setting a delay time before the start of liquid and / or gas injection (if zero, it starts simultaneously with the start of metering); (3) Monitoring the screw position from the start of metering and setting the screw position if injection is to be stopped during metering; (4) Setting the screw position for restarting injection if it is to be restarted; (5) Setting the injection stop command at the screw position if injection is to be stopped before metering; and (6) Setting the delay time (if zero, it starts simultaneously with the completion of metering) if injection is to be stopped simultaneously with the completion of metering or delayed. This signal is connected to separately installed liquid injection devices and gas injection devices. In the case of gas injection, commands are sent from the injection molding machine's program to open and close the injection valve, and in the case of liquid injection, commands are sent to push or stop the plunger. Actuators, for example, operate in conjunction with these commands.

[0233] (Methods to increase the foaming ratio) One way to increase the foaming ratio is to reduce the pressure of the foaming resin filled in the mold. For example, instead of filling the cavity completely with resin, a small amount is filled, known as a short shot. Another method is to reduce the pressure by retracting the screw (suck-back) immediately after filling the cavity with foaming resin, or after a certain period of time has elapsed. Another method is to reduce the pressure of the foaming resin in the cavity by expanding a part of the mold after filling it with foaming resin; this is called an expanded core. In this case, the foaming ratio is not very large because the cavity volume does not change. (In this invention, the foaming ratio is defined as 100 - volume of foamed molded product ÷ percentage of volume of solid molded product. The foaming ratio is also called the weight reduction ratio.) To obtain a large foaming ratio, it is better to implement both core-back and mold-back structures in the mold (for openings such as round holes, if the mold is not core-back, resin may enter the opening when the mold is opened, so in this invention, a core-back shape is used). When GCP is performed, the GCP exhaust should be performed simultaneously with the start of GCP exhaust, during GCP exhaust, immediately after completion of GCP exhaust, or with a slight delay. Both core-back and mold-back have very similar mold movements (mold opening), but as shown in Figures 17 and 18, the case where the parting line 60 (the surface where the fixed side mold and the movable side mold meet) is cut vertically (as shown in part number 62, the fixed side mold and the movable side mold are separated by metal. In Figure 53, the molds are not separated) is distinguished as core-back, and the case where the parting line 60 is cut horizontally, as shown in Figures 19 and 20, is distinguished as mold-back.

[0234] (Control of a molding machine when multiple GCP devices are installed in a single mold) When performing GCP (Ground Control) by installing the GCP devices shown in Figure 15 or Figure 16 in spaces L1, L2, and L3, respectively, as shown in Figures 13 and 14, the control of the start of pressurized air into the molding space of the mold is performed in the same way, using a mold clamping completion signal, etc. That is, the valves numbered 46 open simultaneously. The difference lies in the timing of exhaust. If only one unit is connected, exhaust is performed only by the unit numbered 51, so the pressurized air in L1, L2, and L3 is exhausted all at once. If one unit is connected to each of L1, L2, and L3, the timing of exhaust can be changed. The exhaust signal is performed using the screw position, exhaust timer, etc., and the molding machine's PLC has a program installed that can control multiple units. After exhaust, mold back, core back, mold retraction, and molded part removal are all performed with a single signal, just as in the case of a single machine.

[0235] {Liquid and gas injection from a nozzle {Sinbo (Professor Emeritus Minoru Shinbo, Kanazawa Institute of Technology) process} When a gas or liquid (such as alcohol) is injected during injection from an injection port (with a nozzle at the tip of the heating cylinder; the structure is approximately the same as that used to inject liquid or gas into the aforementioned heating cylinder; a porous sintered metal that allows gas and liquid to pass through is used) and the liquid or gas is dispersed into the resin during injection by the force of the injection and then pressurized and dissolved, (1) the injection start should be set to zero, and a delay time should be set (if zero, it will be simultaneous with the injection start). (2) To stop, the injection stop command should be set at the screw position. (3) Of course, if injection is stopped during injection and then restarted, the stop and restart should be done by setting the screw position (which can be arbitrarily set). In addition to providing liquid and gas inlets on the nozzle, the hot runner is also provided with similar liquid and gas inlets and controlled in the same way by the injection molding machine's program.

[0236] In the case of a mixed process, where foaming properties are imparted by gas, liquid, or solid, and the foaming resin and non-foaming resin are mixed within the nozzle during the injection stage, the control is the same as the control for injecting liquid or gas from the nozzle as described above. Of course, this mixed process can also be implemented with a hot runner.

[0237] (Control of GCP equipment by sequencer of injection molding machine) In the case of GCP, commands are given from the injection molding machine to the GCP device as follows: (1) Once it is confirmed that the mold is closed and (2) nozzle contact is complete, (3) the injection valve indicated by part number 46 in Figures 15 and 16 is opened to pressurize the inside of the mold with gas (pressure process). (4) The GCP time is set in advance, and when the timer time is up, the filling of foamed resin into the cavity begins (injection process). (5) If a pressure gauge indicated by part number 56 is used instead of a timer, the filling of foamed resin into the cavity begins when the preset pressure is reached. (6) GCP exhaust is performed during or after injection (exhaust process). During injection, the screw position at the start of injection is used as the starting position, and when the screw passes an arbitrarily set position, the exhaust valve indicated by part number 51 in Figures 15 and 16 is opened to release the gas inside the mold into the atmosphere (exhaust process). (7) When exhausting simultaneously after injection is complete, or when exhausting is delayed, the delay time can be set (if zero, it will be simultaneous with the completion of injection) (exhaust process). When a means is used to lower (retract) the screw to a predetermined position after a certain period of time has elapsed from 0 after the completion of injection to reduce the pressure of the foaming resin filled in the cavity and make it easier to foam, (8) In addition to exhausting during injection, simultaneously with the completion of injection, or after a certain period of time has elapsed after the completion of injection as described above, when suck-back is started simultaneously, during suck-back, or with a delay, the delay time can be set {if zero, it will be simultaneous with the completion of retraction (when it has retracted to the set position)}.

[0238] This method involves enlarging a portion of the mold (breathing, expanding core, or expansion core) to reduce the pressure of the foaming resin filled in the cavity, making it easier to foam. The timing of breathing can be (1) simultaneous with the completion of resin filling into the cavity, or a delay time can be set (zero means simultaneous with the completion of injection) (exhaust process). Breathing can be performed using hydraulic or pneumatic cylinders or motors installed in the mold, or using the ejector mechanism of the injection molding machine, all of which are commanded by the injection molding machine's program. Breathing and suck-back are different operations, but they can sometimes be performed simultaneously.

[0239] (Core back and molded back) First, the difference between core-back and mold-back is explained using Figures 17, 18, 19, and 20. (Figures 53 (before core-back) and 54 (after core-back) also show the mold structure of core-back.) As shown in part number 62, the core-back mold has a structure in which the movable mold 61 fits into the fixed mold 59 at part number 60 (vertical parting). (Figure 17) In this state, foamed resin is filled into the cavity 21 formed by parts 59 and 61. If GCP is performed, after the GCP is exhausted, (1) set a delay time (if zero, it will be simultaneous with the completion of exhaust). As shown in Figure 18, part 61 is retracted (core back indicated by the arrow of part 63), expanding 21, and a gap 67 is created in the parting 60. Since parts 59 and 61 of the mold are vertically cut 62, the molten resin will not overflow. Mold back will be explained using Figures 19 and 20. In Figures 17 and 18, the parting line 60 is a vertical trim 62, but in Figures 19 and 20, the parting line 60 is a flat trim 64. After filling 21 with foamed resin, the movable mold 61 is retracted (mold back, indicated by the arrow at reference number 65) to enlarge 21. The parting line 60, which is a flat trim 64, opens up as shown by reference number 66 as it is retracted, and the force holding the resin inside 21 is lost. However, if the gap created by the retraction is small, and a skin layer is formed on the surface using GCP, cooling and solidification will proceed, and a solidified layer will be formed on the surface, so the molten resin inside will not leak out.

[0240] In the case of GCP implementation, after the exhaust of compressed air is complete, (1) set a delay time (if zero, it will be simultaneous with the completion of exhaust). As shown in Figure 20, part number 61 is moved back (part number 65), and part 21 is enlarged, creating a gap 66 in part 60, and the reason why molten resin does not overflow out is as described above. Core-back and mold-back differ in that a core-back shape in the parting line makes the mold structure complex and raises concerns about increased mold costs. Therefore, the mold-back structure shown in Figures 19 and 20 is preferable for parting lines. In the case of holes, a mold-back (flat cut) would leave gaps, raising concerns about resin seeping in. In this case, a core-back (vertical cut) structure is used. Both core-back and mold-back can be easily implemented if the programs for these operations are pre-programmed into the internal control panel of the injection molding machine. Direct-pressure injection molding machines can achieve a certain degree of accuracy in retracting the mold, but in the case of toggle mechanisms, the accuracy of retraction may be lower than that of direct-pressure machines. In such cases, puller bolts or similar components may be incorporated into the mold to improve the accuracy of retraction (the accuracy of the retraction distance for core-back and mold-back). The above-mentioned (1) programs that impart foaming properties to the molten resin in the heating cylinder using gaseous, liquid, or solid foaming agents alone or in combination, (2) programs such as screw retraction and breathing to reduce the pressure of the foaming molten resin filled in the cavity, and (3) programs such as compressed air injection and exhaust when performing GCP, as well as core back and mold back programs, can be easily implemented by pre-installing them in the injection molding machine. Of course, for example, it is simpler, safer, and cheaper to integrate these programs into the control panel of the injection molding machine rather than manufacturing a separate controller with a built-in sequencer for the GCP device, which would receive signals from or send signals to the injection molding machine to establish an interface between them.

[0241] (Methods of mold-back and core-back) In mold-back molding, the molded part temporarily separates from the fixed side (cavity) of the mold. It then reattaches to the fixed side due to foaming force, resulting in mold transfer. However, because the pressure during foaming is low, mold reproducibility (transferability to the mold) can be poor. The following describes a method to solve this problem.

[0242] (Means for controlling the timing of L1, L2, and L3 exhausts) In GCP, the exhaust of L1 (the space at the bottom of the movable insert, or the space in the ejector box), L2 (the molding space), and L3 (the space at the bottom of the fixed insert) is not done simultaneously, but with a time delay. This allows for mold-back operations while pressurizing from the movable side with the GCP pressure. In practice, the compressed air in L1, L2, and L3 is released either before the foam resin fills the cavity (L2), either at the time of filling or some time after filling, with L3 being the first to be exhausted. Subsequently, L2 is exhausted simultaneously with, or slightly delayed from, L3. When mold-back operations are performed with compressed air in L1 (the molded product is compressed from the movable side to the fixed side by the pressure of the compressed air), the compressed air in L1 is released all at once from the parting line 60, etc., as a gap is created when the mold opens. At this time, as described above, mold-back operations are performed while the mold is pressed (transferred) by the force of the compressed air in L1, so the mold transferability is maintained. The mold structure used is not suitable for mass production because, in the ejector box structure shown in Figure 10, the compressed air inside the large-volume ejector box (L1) is exhausted all at once, producing a very loud noise. In the mold structure that seals the ejector pins shown in Figure 11, the amount of compressed air exhausted is relatively small, making it safer to implement. The pressures of L1, L2, and L3 can be the same (L1=L2=L3), but if L1 is slightly higher, such as L1>L2=L3, the effect of fixing the mold from movable to fixed is greater. In this case, the GCP device is a multi-stage exhaust GCP device that exhausts L1, L2, and L3 separately {three devices as shown in Figure 15 are prepared, and L1, L2, and L3 are connected separately to each. One compressor 43 is sufficient, but if the pressures of L1, L2, and L3 are to be changed, a regulator (not shown) should be installed before reference numeral 46. The device in Figure 16 is more suitable for the mold structures shown in Figures 11 and 14. Naturally, by installing a regulator, it becomes possible to change the pressures of L1, L2, and L3. (Figure 38)

[0243] (Another method is to pressurize the movable side with gas.) Figures 31 to 35 show a method for using a seal-type mold of ejector pins shown in Figure 11, which includes a gas pressurization circuit (designated as 90, 92, and 94) separately provided on the movable side (gas is injected into the gap between the resin and the mold on the movable side of the cavity, and pressurization is applied from the movable side to the fixed side by the force of the gas, which is separate from the compressed air), and gas pressurization pins (designated as 89, 91, and 93). L3 and L2 are exhausted, and compressed gas is introduced from a separately installed circuit. The pressure of this gas is used to press the movable side against the fixed side, causing a mold-back process that increases the foaming ratio. Part numbers 89, 91, and 93 are gas pins for pressurizing from the movable side to the fixed side. In this method, the gas outlet is surrounded by ribs to prevent the gas introduced into the gap from escaping. (Reference number 101 in Figure 35) The height of these ribs should be greater than the distance at which the mold back is performed. If the mold back is performed with the pressurized gas being applied from the movable side to the fixed side without exhausting the pressurized gas, the pressurized gas in the resin will begin to solidify in the cavity, and the gap between the resin and the mold will widen by the distance of the mold back, so the gas will be released into the atmosphere. Pressurized air is applied to L1, L2, and L3, and the foamed resin is filled into the cavity (L2). During and after filling, L3 is evacuated, and simultaneously or slightly later, L2 is evacuated. After the foamed resin has filled the cavity, gas is ejected from reference number 100, and the gas is introduced into the gap between the resin and the mold and pressurized as described above. The initial pressurized air (L1, L2, L3) is used in a multi-stage exhaust system, where L3 is evacuated separately, then L2, and finally L1.

[0244] (Another method is to pressurize the movable side with gas.) Figures 31 to 35 show a method for creating a seal-type mold for an ejector pin, as shown in Figure 11. This method involves providing a double-layered ejector pin (reference numeral 91), an ejector plate, and a gas circuit (reference numeral 92) for the ejector plate. Gas is then applied through the gap between the inner core and outer cylinder of the double-layered ejector pin (gas is introduced into the gap between the resin and the mold on the movable side of the cavity, and the force of another gas is used to pressurize from the movable side to the fixed side). In this case as well, the structure is shown in Figure 31. The structure of the pressure pin is the same as in Figures 32 to 35, the only difference being the location of the gas pressurization on the movable side (the difference between reference numeral 89 and reference numeral 91). Figure 31 also shows the case where a gas pressure pin is provided on the ejector plate. Another method is to provide a structure (reference number 107) that suppresses gas pressure on the movable side mounting plate (reference number 28). In these cases as well, while single-stage exhaust is acceptable for GCP (compressed air), multi-stage exhaust is preferable.

[0245] (Method of pushing with an ejector pin) In injection molding machines, an ejector mechanism is used so that the mold retracts, but the ejector pin does not retract. By keeping the ejector pin pressed, the molded product does not detach from the fixed side during mold backing, etc. In these cases, a single-stage exhaust for the GCP is acceptable, but a multi-stage exhaust is preferable.

[0246] (Method of pressurizing with gas from the inside) One method for creating molded products is high-pressure gas hollow molding (e.g., GasTy-2, Simpress, Asahi Kasei's AGI). This method is applied to mold backing in foam molding. By injecting high-pressure gas into the foamed resin before exhausting L1, L2, and L3, the resin expands due to the pressure of the internal high-pressure gas. The foamed resin inside the cavity is suppressed by the internal gas pressure and does not foam. Even when mold backing is performed, the foamed resin inside the cavity does not separate from the fixed and movable sides, and expands in accordance with the mold backing. When the high-pressure gas injected inside is exhausted into the atmosphere simultaneously with the completion of mold backing, or with a slight time delay, the pressure that was suppressing foaming from the inside is released, and foaming begins inside. The structure of the gas injection pin can be made hollow by inserting the gas nozzle (reference number 100) into reference number 104 (to a position approximately half the thickness of the plate) as shown in Figure 35. The exhaust of the GCP (compressed air for L1, L2, and L3) should be completed before mold-backing, etc. In this case, there are no particular restrictions on the order of L1, L2, and L3 exhaust. Generally, it is completed before mold-backing, etc.

[0247] In the 3D CAD drawings of the product in the example {Figures 21 and 22}, the parting of hole 67 is a core-back structure, formed to avoid gaps in the mold even when the mold is retracted. The parting indicated by part number 68 is a mold-back structure. Some partings are flat cut (part number 68) only on the movable side, while some partings are double-sided carved (part number 69) with an R-shape on the fixed side to create an R-shape. Figure 21 shows the fixed side, and Figure 22 shows the movable side. Part number 70 indicates the top thickness, which is 2 mm when the mold is closed. Using this mold, core-back (vertical cut) and mold-back (flat cut) were performed with partings of 0.5 mm and 1 mm, and the respective foaming ratio (weight reduction rate) and mold reproducibility were confirmed.

[0248] (Heat and Cool) In GCP (Glass Plastic Forming), the thickness of the surface skin layer changes depending on the temperature of the mold surface, or in other words, the cooling and solidification rate of the molten resin filled in the cavity. Naturally, higher temperatures result in a thinner layer. Figure 23 shows a method for raising the mold temperature using superheated steam generated by a boiler (heat and cool is common, but in this invention, a device using magnetic fluid, electromagnetic induction, high-frequency superheating, etc.). Reference numeral 71 indicates a heat transfer medium, which can be polyethylene glycol, glycerin, silicone oil, or mineral oil. Reference numeral 72 indicates a heating element containing small magnetic particles or powders (e.g., ferromagnetic materials such as iron, stainless steel, nickel, or cobalt). External reference numeral 73 indicates an IH heater coil; when current is applied (ON), a high-frequency current is generated, heating the internal magnetic material (reference numeral 72), and this heat is transferred to the heat transfer medium (reference numeral 71), thus heating the heat transfer medium. When the current is turned off (OFF), heating stops, so the temperature can be controlled by turning the current ON / OFF. Reference numeral 74 indicates a vane located inside the circuit, to which a magnet (reference numeral 75) is attached. When the external magnet (reference numeral 76) is rotated, the change in the magnetic field causes the internal vane (reference numeral 74) to rotate, circulating the heated heat transfer medium. The flow rate (velocity) of the heat transfer medium changes depending on the rotation speed, allowing the heating efficiency to be controlled. Alternatively, the Arago disc principle can also be used to rotate these blades. Reference numeral 78 indicates the flow direction of the heat transfer medium, and reference numeral 79 indicates the mold inserts to be heated. Reference numeral 81 indicates the heating device, and reference numeral 82 indicates the circulation device. Reference numeral 83 indicates the piping through which the heat transfer medium 71 flows, and is made of steel pipe. Reference numeral 83 indicates that a flexible hose can also be used as long as it has sufficient heat resistance. Although not shown in the diagram, Figure 23 incorporates a flow meter, thermometer, and pressure gauge to ensure reliable temperature control. Glycerin is recommended as the heat transfer medium due to its ability to reach high temperatures, its water solubility, and ease of use. Glycerin has the chemical formula C3H8O3, a melting point of 17.8°C, and a boiling point of 290°C. As it is a liquid, it has a higher specific heat ratio than pressurized steam from a boiler, resulting in better heat exchange efficiency. Glycerin has low toxicity and is water soluble, so it can be easily removed by washing with water compared to oils and fats, thus less likely to worsen the working environment. Ethylene glycol can also be used, but its use is not recommended due to its toxicity. Part number 77 is a flow control valve, and part number 80 is a filter designed to keep the magnetic material inside part 81.

[0249] Cooling can be achieved by circulating cooling water through circuits provided in the mold. Alternatively, a gas can be circulated, or the heat of vaporization of ethanol or similar substances can be used. These circuits can be created in the mold by drilling holes with a gun drill, and these heating and cooling circuits can be fabricated into the inserts and then joined together using diffusion welding, a heat treatment method, to create circuits with high thermal efficiency. Copper powder and nickel powder are used as adhesives for diffusion welding. In the case of GCP, the higher the surface temperature of the cavity (L2), the thinner the surface skin layer becomes. As mentioned above, in addition to heating the mold with a high-temperature heat transfer medium, there is a method of installing a coil in the removal machine and inducing high-frequency waves on the mold before filling with foamed resin (just before closing the mold) to raise the temperature of the mold surface {for example, Asahi Kasei Corporation's BSM}.

[0250] In addition, the mold is given an insulating layer to slow down cooling and solidification. The insulating layer can be coated with Teflon (product name), ceramic coating, or ceramic plasma coating. Alternatively, materials such as WC (tungsten carbide), TiN (titanium nitride), CrN (chromium nitride), alumina, and DLC (diamond-like coating, diamond-like carbon) can be applied. These materials have an insulating effect, so the cooling and solidification rate of the foamed resin molten in the cavity slows down, resulting in a thinner surface skin layer. Using these methods, the cooling and solidification rate is slowed by the foamed resin's own temperature, which also has the effect of increasing its fluidity.

[0251] (Paint for plastics) In the present invention, when using paints for cosmetic purposes (cover marking) on ​​resin molded products, if the base resin is a thermoplastic resin, the heat deformation (heat resistance) temperature of the resin is low, so paints that dry or harden at low temperatures, such as acrylic resins, styrene-modified acrylic resins, and urethane paints, are selected. Paints with low baking temperatures are selected. In the case of PP molded products, if the above paints are applied directly, the affinity between the PP molded product and the above paint (coating film) is poor, and sufficient adhesion cannot be obtained (exercised). Therefore, when painting PP molded products, a primer mainly composed of halogenated (chlorinated, brominated) PE, halogenated PP, or maleic acid-modified resin (PP, PE) is applied, and then the above topcoat is applied. The primer and topcoat paints may be solvent-based or emulsion-based. After applying the primer and allowing it to dry to the touch, it is forced to dry slightly, and then the above cosmetic paint (topcoat paint) is applied. The above paints are solvent-based, emulsion-based, and water-based. Powder-based paints may also be used.

[0252] (Pre-treatment before painting) The most common painting methods are air spray painting or electrostatic painting. To obtain a beautiful paint film, the paint is diluted with a special thinner to a viscosity suitable for the work. As a pre-treatment for painting, dust removal and static electricity removal are performed on the object to be painted to prevent painting defects, such as removing dust, debris, oil, mold release agents, and static electricity. Some manufacturers manually wipe down surfaces with alcohol, such as isopropyl alcohol (isopropanol, IPA), then air-blow them before spray painting. Others automate these pre-treatment steps, such as showering or immersing in a degreasing solution, followed by rinsing, drying, and drying. When baking soda is used as a foaming agent, these pretreatment methods alone are insufficient to completely remove foaming residue (sodium carbonate) and undecomposed foaming agent (baking soda). If the paint is applied in this state, the foaming residue and other substances will hinder the adhesion of the paint film, which is a problem. These residues cannot be completely removed by washing with water alone, but these alkaline substances can be neutralized with acid to become water-soluble and easily removed by washing. Therefore, the inventor solved the problem of poor adhesion by showering or immersing the object to be painted with a dilute aqueous solution containing organic acids such as acetic acid, citric acid, and succinic acid as a pre-treatment before painting, and then washing it off with room temperature or warm water. When immersion is used, the cleaning effect is enhanced by using ultrasonic cleaning or bubbling in combination.

[0253] (Core-back mold structure) Figures 53 and 54 illustrate cases where the mold structure differs from that shown in Figures 17 and 18. Figures 17 and 18 show vertical seams between metals. Figures 53 and 54 show the movable side (number 157) entering the molded product, filling it with foamed resin, and then retracting the movable side to increase the foaming ratio. Number 155 indicates the space (molding space) in the movable side mold and the fixed side mold where the resin enters (is filled). Number 156 shows the non-expanded outer molded product when number 61 is retracted.

[0254] (Another shape of O-ring used for sealing, such as in PL) The O-ring number 33 in Figure 11 usually has a circular cross-section. After molding back and vacuuming, a method is used to eliminate raindrops. Even after molding back and opening the parting line, the parting line needs to seal sufficiently, so the O-ring number 33 is made thicker. Otherwise, the V-ring shown in Figure 55 and the U-ring shown in Figure 56 are used. Numbers 159 and 160 are openings where gas enters and expands outward due to the pressure, providing a seal. Number 158 shows the cross-section of the V-ring, and number 161 shows the cross-section of the U-ring. Figure 57 shows the case where a V-ring is combined with a normal circular O-ring, and Figure 58 shows the case with a U-ring.

[0255] As mentioned above, the O-rings in Figures 55 and 56 have a directional sealing action. When pressurizing the molding space and then vacuuming after the pressurized air is released, a V-ring (V-seal ring) or U-ring (U-seal ring) with openings 159 and 160 facing the molding space, and a V-ring or U-ring facing the opposite direction from the PL direction can be placed in the molding space to create a seal on both sides. An O-ring 162 may also be placed in between (Figures 59 and 60). Figures 61 and 62 show a shape where Figure 55 is integrated on both sides, and Figure 63 shows a shape where Figure 56 is integrated on both sides. In some cases, an O-ring shape with number 162 may be placed in the center. The material of these rings can be the same as commercially available O-rings, such as NBR or urethane rubber. Silicone rubber or fluororubber may be used as needed. The hardness of the rubber should be changed to the optimal hardness depending on the size of the mold and the pressure of the pressurized air. Although not shown, in Figures 55 to 62, the leftmost point of the drawing is the molding space, and the rightmost point is the outside through the parting line (PL). The PL surface in Figures 55 to 62 is the surface on which the seals in these drawings are located. (Not shown.) Attachment number 163 is a V-seal in Figure 55 with opening 164 facing outwards, and attachment number 166 is a U-seal in Figure 55 with opening 165 facing outwards. Attachment numbers 159, 160, 164, and 166 may be fitted with springs in Figure 29, O-rings in Figure 30, etc., similar to Figures 24 to 26, to allow them to be opened outwards (load-operated).

[0256] (Vacuum pump) This section describes a method to eliminate raindrops, a GCP-specific problem, by further vacuuming the pressurized air inside the mold after GCP exhaust. In the GCP apparatus shown in Figure 15 or Figure 16, opening the exhaust valve numbered 51 and exhausting the pressurized air inside the mold, followed by mold back and core back, allows the pressurized air that enters the gap between the mold and the resin and causes raindrops to be exhausted to the outside (through the exhaust valve numbered 51 of the GCP apparatus), reducing, making less noticeable, or eliminating raindrops. Further vacuuming can reduce raindrops even more.

[0257] The mold is closed, and compressed air is applied to the seal mold shown in Figures 10 and 11 to fill it with foamed resin. During and after filling, valve 51 is opened to release the compressed air. During and after the release, the PL of the mold is opened (to perform mold back and core back) to release any compressed air that has entered the gap between the mold and the resin and is causing raindrops. When performing vacuum evacuation, valve 51 is closed, and part number 174 of the vacuum evacuation device shown in Figure 63 is opened to draw the compressed air inside the mold into tank part number 169. This reduces the compressed air in the gap between the resin and the mold, allowing the molded product to be transferred to the mold by its foaming force. High mold surface temperature, high molten resin temperature, and high compressed air pressure result in more raindrops, but these problems can be solved by employing vacuuming. In Figure 63, part number 177 is a vacuum pump, part number 173 is a solenoid valve, and is driven (ON and OFF) by the pressure set by part number 170, a pressure gauge (with signal output capability) that checks the pressure in part number 169 tank. Part number 176 is a manifold, part number 171 is a hose, and part number 172 is a one-touch coupler corresponding to the vacuuming, which are connected to L2 of the mold (compressed air circuit to the molding space). Part number 168 is a check valve, and the arrow in part number 175 indicates the flow of vacuumed compressed air.

[0258] Next, the present invention will be described based on the examples. The resins used in the experiment are described below. For ABS, we used Clarastic GA-501 (product name) from Nippon A&L Co., Ltd. For PS, we used Toyo Styrofoam G100C (product name) from Toyo Styrene Co., Ltd. For HIPS, we used Toyo Styrofoam H450 (product name) from Toyo Styrene Co., Ltd. For m(styrene-modified)-PPE (polyphenylene ether), we used Zylon 100Z (product name) from Asahi Kasei Corporation. For PC / ABS (polymer alloy of PC and ABS, blended polymer), we used Multilon T3714 (product name) from Teijin Chemicals, for PC, we used Yupiron S2000 (product name) from Mitsubishi Engineering Plastics Corporation, and for PP, we used Noblen AZ864 (product name) from Sumitomo Chemical Co., Ltd. The molding machine used is an injection molding machine manufactured by Toyo Machinery & Metal Co., Ltd. The PLC in this molding machine manufactured by Toyo Machinery & Metal Co., Ltd. is programmed to control, command, and instruct the GCP device, liquid injection device, hollow molding device, pressure molding device, and mold temperature controller shown in Figure 23 of the present invention. [Example 1]

[0259] (Manufacturing of foaming agent master batches) As an inorganic blowing agent, baking soda powder was prepared; as an organic blowing agent, ADCA powder was prepared; and as a foaming nucleation agent, monosodium dihydrogen citrate (monosodium citrate, monosodium citrate, monosoda citrate) powder was prepared. The above baking soda, ADCA, monosoda citrate, and ABS, PS, and PP pellets were sent to Towa Chemical Co., Ltd. (6-66-35 Wakae-Higashi-cho, Higashi-Osaka City, Osaka Prefecture 578-0935) and H processing (the details of H processing are unknown as they are a trade secret of Towa Chemical; however, this was the explanation given by Towa Chemical) which is an improved version of MC processing and SC processing, was requested, and the respective blowing agents (baking soda and ADCA) and foaming nucleation agents were supported on the surface of the respective resin pellets. Master batches of foaming agents for ABS with 10 wt% baking soda supported on ABS (development code; Wn-B-baking-soda-10), master batches of foaming agents for PS with 10 wt% baking soda supported on PS (development code; Wn-S-baking-soda-10), master batches of foaming agents for PP with 10 wt% baking soda supported on PP{AZ864 (block copolymer MI value = approximately 30) (development code; Wn-P-baking-soda-10), master batches of foaming agents for ABS with 10 wt% ADCA supported on ABS (development code; Wn-B-ADCA-10), master batches of foaming agents for PS with 10 wt% ADCA supported on PS (development code; Wn-S-ADCA-10), and master batches of foaming agents for PP with 10 wt% ADCA supported on PP(AZ864) ( We manufactured the following master batches of foaming nucleating agent for ABS (development code: Wn-B-CANa-10), which consists of ABS with 10 wt% monosodium citrate supported on it; PS with 10 wt% monosodium citrate supported on it (development code: Wn-S-CANa-10); and PP with PP with 10 wt% monosodium citrate supported on it (development code: Wn-P-CANa-10). In Example 1, H processing was used, but it is also possible to manufacture the product using pellet processing by Hexa Chemical Co., Ltd. (Higashi-Osaka City). In addition, it has been confirmed that the same product (master batch of foaming agent, master batch of foaming aid, etc.) can be manufactured using the methods described above, such as the Henschel mixer. This can also be done with Aichi Electric Co., Ltd.'s RHM-(SJ) (product name) and RMDHLV (product name) rocking mixers. [Example 2]

[0260] (Manufacturing of foamed molded products without GCP) Foam molding was performed using the molds shown in Figures 21 and 22 without performing GCP, using appropriate foaming agents for each of the above-mentioned ABS, HIPS, m-PPO(E), PP, PC, and PC / ABS (for example, Wn-P-ADCA-10 for PP), and, if necessary, foam nucleating agents. Of course, since foam molding was performed without GCP, the presence of swirl marks on the surface of the molded product was visually confirmed. The molded product was broken open and the inside was examined to confirm the presence of foam cells and the formation of a foam layer. Figures 42 and 43 show the results for each molded product. Figure 42 shows the combination of each molding resin and foaming agent master batch, the amount added, and the amount of foam nucleating agent added. Similar results were obtained when the amount of each foaming agent added was 3 wt% and 5 wt%. When the molding resin is PP, the foaming agent master batch was manufactured using acid-modified PP that is compatible with the PP intended for molding, so there is no occurrence of silver (code 2) near the gate as shown in Figures 1 and 2. In the Wn-P-baking soda-10 foaming agent for PP, the particle size of the baking soda was made finer to 0.5 μm to produce a master batch of the foaming agent. This reduced the amount of effervescent gas generated from each individual baking soda particle, thus minimizing the appearance of swirl marks. However, since GCP (Ground Control Panel), as described later, was not used, swirl marks still appeared on the surface. [Example 3]

[0261] (Manufacturing of foamed molded products with GCP (Good Clinical Practice)) In the above-described embodiment 2, the mold structure was a sealed mold using the ejector box shown in Figure 10 (Figure 11 is also possible), with one GCP device shown in Figure 15 connected to L1 to L3. The injection molding machine used was a 350-ton (Si-350-6S) manufactured by Toyo Machinery & Metal Co., Ltd. The injection molding machine (Si-350-6S) has the GCP program {pressure (gas inlet and outlet) into the mold, exhaust, suck back, breathing, core back, mold back, etc.} which controls the GCP device shown in Figure 15 built into the machine's program. Therefore, the device in Figure 15 does not require a separate controller; it is operated by the program installed in the injection molding machine's program. The weight of the product in the mold shown in Figure 13 is approximately 100 grams per piece (about 200 grams for both). Once the injection molding machine confirmed that the mold was tightly closed and making contact with the nozzle, it sent a signal to open the injection valve 46, and compressed air from the compressor 43 was sent from the injection valve 46 into the mold spaces L1 to L3. The output signal of the pressure gauge 56 was set to 0.8 MPa, and when the pressure gauge reached this level (it is presumed that the pressure inside the mold was also the same), the injection molding machine received this signal, opened the pneumatically operated shut-off nozzle, and filled the cavity (space L2) with foaming resin from the heating cylinder. When the filling rate (vol%), defined as the volume of molten resin filled in the cavity ÷ the volume inside the cavity × 100, reached 95 vol%, the injection molding machine opened the exhaust valve 51 and exhausted the gas from inside the mold L1 to L3. The external appearance and internal foam layer are shown in Figure 44. When the molding resin is PP, the base resin of the foaming agent master batch is compatible with compatible PP, and the PP used to support the foaming agent is also acid-modified (e.g., maleic acid) PP that is compatible with (solubilates with) the molding material PP. As a result, there is no silver formation near the gate as shown by symbol 2 in Figures 1 and 2. [Example 4]

[0262] (Differences in the timing of exhausting compressed air from inside the mold) In Example 3, the exhaust time was set to (1) immediately after filling the cavity to 100% and 3 seconds after filling. However, the appearance and the internal foam layer remained unchanged, suggesting that delaying the exhaust timing did not have a significant effect. Conversely, when the exhaust was performed at a filling rate of 60% (during filling), the foaming force (foaming force of the foaming gas, foaming force) could not be suppressed at the end of the flow, resulting in the formation of swirl marks at the end of the flow. If exhaust is initiated when the molded space is filled to 90% or more with foamed resin that has been imparted with foaming properties, no swirl marks will be observed at the end of the flow. [Example 5]

[0263] (GCP pressure) In Example 3, the pressure of the compressed air in the GCP (pressure within the molding space) was set from 0.8 MPa to 1.0 MPa, 1.2 MPa, and 1.4 MPa. There was no change in appearance or foam layer due to the difference in compressed air pressure. When the compressed air pressure was reduced to 0.6 MPa, the foaming force could not be suppressed, and swirl marks occurred throughout. Swirl marks were particularly frequent when ADCA was used as the foaming agent. This is presumed to be a result of the low solubility of nitrogen gas, a foaming gas, in the resin used. The pressure of the compressed air in the molding space of the GCP changes depending on the type of foaming agent, the amount of foaming agent added, and the type of resin. Naturally, if the compressed air pressure is high, swirl marks can be eliminated even if a large amount of foaming agent with high foaming force (e.g., ADCA) is used. [Example 6]

[0264] (Paintability of molded products without GCP) In Example 2, the molded products obtained (the product numbers (codes) are shown in Figure 43) were each painted with a suitable paint. For the ABS, HIPS, m-PPO(E), PC, and PC / ABS molded products, a paint mainly composed of styrene-modified acrylic resin (Ripelle S#1100 (product name, product number) manufactured by Toupe Co., Ltd.) was used. For the PP molded product, a primer was required, so it was first treated with Multi-Primer EXC-3000 (product name, product number) manufactured by Musashi Paint Co., Ltd., and then painted with the topcoat paint EC-GPX79-Eco High-Ulex (color: silver (mixing ratio of main agent to hardener: 10:1) (product name, product number)) manufactured by Musashi Paint Co., Ltd. to obtain painted molded products. A grid test was performed on the painted surfaces of these molded products in accordance with JIS K-5600-5-6. The results are shown in Figure 45. Swirl marks occurred on all of the molded products in Figure 45. Since the swirl marks consist only of a thin resin film on the surface of the molded product, there was almost no adhesion between the swirl marks and the main body of the molded product, and these swirl marks were the cause of peeling.

[0265] The detailed method of coating in Example 6 was as follows: For molded products of ABS, HIPS, m-PPO(E), PC, and PC / ABS, (1) the surface was degreased using isopropyl alcohol (IPA), (2) the IPA was allowed to evaporate by leaving it indoors, and (3) spray coating was applied using the above-mentioned paint suitable for the material of each molded product. The film thickness was approximately 10 μm. (4) After setting for about 3 minutes, (5) the drying temperature was 50-60°C and the drying time was 45 minutes. (6) After leaving it indoors for 48 hours, the adhesion test described above was performed and the results were obtained. In the case of molded products of PP, (1) the surface was degreased using IPA, (2) the IPA was allowed to evaporate by leaving it indoors, and (3) since a primer treatment mainly composed of chlorinated polyolefin resin is required, Multi-Primer EXC-3000 was sprayed first, and after setting for 5 minutes, it was dried at 60°C for 30 minutes, resulting in a film thickness of 3 μm. (4) The above-mentioned suitable paint (EC-GPX79-Eco High-Urec, silver in color) was spray-painted. The film thickness was approximately 10 μm. (5) After setting for 5 minutes, (6) it was dried at a drying temperature of 60°C for 45 minutes. The film thickness was 15 μm. After being left indoors for 48 hours, the adhesion test described above was performed in accordance with JIS K-5600-5-6, and the results are shown in Figure 45. When painting foamed PP molded products, first apply a primer made of maleic acid-modified PP to the PP, and then paint with a two-component urethane paint or the like. At that time, it is preferable to use a primer made of the same material as the foaming agent master batch of maleic acid-modified PP (for example, Hardlen NZ-1015). Of course, different materials can be used, but in that case, the adhesion of the primer to the foamed molded product containing maleic acid-modified PP should be checked. Maleic acid-modified PP can be used even if the modification rate differs (for example, Toyobo's Hardlen NZ-1015 was used for the production of the foaming agent master batch, and Arrowbase DA-1010 was used as the primer for painting). [Example 7]

[0266] (Paintability of molded products with GCP) In Example 7, the molded product used in Example 6 was subjected to GCP (Ground Pressure Testing) to obtain a molded product with a smooth surface and no swirl marks (the molded product number (code number) is shown in Figure 44). A painted molded product was obtained using the same paint and method as in Example 6. Similar to Example 6, a grid test was performed in accordance with JIS K-5600-5-6 to confirm primary adhesion, and the adhesion of the coating film on all molded products was good at 100 / 100. (Figure 44)

[0267] To confirm secondary adhesion, a salt spray test (SST) was conducted for 240 hours according to JIS K5600-7-1. While no peeling of the coating was observed in the samples using ADCA as the foaming agent, blistering was observed in the samples using baking soda as the foaming agent (Figure 47). This was presumed to be because, after the baking soda foaming agent decomposed thermally to generate carbon dioxide and water vapor, either sodium carbonate or undecomposed sodium bicarbonate, or both, remained attached to the molded product surface (only degreasing with IPA), causing the blistering. Blistering was also observed in water resistance tests according to JIS K5600-7-2 (e.g., 240 hours at 50°C and 98% RH) and JIS K5600-6-2 (e.g., 240 hours immersion in 40°C hot water) (Figure 47). [Example 8]

[0268] (Removal of foaming residue) In Example 7, the cause of blistering was suspected to be sodium carbonate and undecomposed sodium bicarbonate. Therefore, only the molded product using baking soda as a foaming agent was degreased with IPA and then immersed in a 1 wt% aqueous acetic acid solution for 10 minutes to solubilize the sodium carbonate and undecomposed sodium bicarbonate in water (acetic acid is acidic, so it neutralizes (reacts) and makes water solubility easier). After rinsing with water and drying, the acid-washed molded product was subjected to a 240-hour SST test as in Example 7, followed by a water resistance test and a saltwater immersion test. No blistering of the coating film occurred. (Figure 47) The results were similar when a 5 wt% citric acid aqueous solution was used instead of acetic acid, and an improvement in the adhesion of the coating film was confirmed. From the results of Example 8, it was confirmed that when baking soda is used as a foaming agent, pickling improves the adhesion of the coating film. Although baking soda was used in Example 8, similar results were obtained with potassium bicarbonate. [Example 9]

[0269] In Example 2, the mold shown in Figure 13 was used. In Example 9, the mold shown in Figure 14 (details in Figure 12) was used, in which the ejector pin was sealed using load-type O-rings, U-shaped packings, V-shaped packings, L-shaped packings, etc., as shown in Figures 24, 25, 26, 27, and 28. GCP was performed in the same manner as in Example 2. In all cases, no swirl marks occurred. However, when the filling speed was set to the fastest and the pressure to the highest level, the rapid increase in pressure resulted in insufficient gas (gas transfer, degassing, etc.) escape from the GCP, causing short molding, discoloration, and burning. When the GCP device was changed to the one shown in Figure 16, which has a 55 sub-tank, even with high-speed and high-pressure filling of molten resin, the force of filling returned (transferred) the GCP gas to the sub-tank 55, eliminating the occurrence of short molding, discoloration, and burning caused by the rapid increase in pressure. In a GCP (Gross Compression Packaging) system, having a 55 sub-tank significantly reduces the pressure of the compressed air within the molding space as the resin is filled, thus eliminating discoloration and burning. In Figure 11, the ejector box L1 serves as this 55 sub-tank. [Example 10]

[0270] (Mold back and core back) In Example 2, immediately after exhausting the compressed air (after the completion of the GCP process), the mold was moved back by 0.5 mm {by ​​lowering the movable side of the mold by 0.5 mm in the injection molding machine to perform mold back and core back}, resulting in a weight reduction of 25% (expansion ratio = 100 - 0.5 mm {distance of the movable side of the mold's retraction, mold opening distance + 2 mm (initial top thickness)} ÷ 2 mm (initial top thickness) × 100). Immediately after exhausting the GCP, the mold was moved back by 1 mm to obtain a foamed molded product with an expansion ratio of 50%. Since GCP was performed on both the 0.5 mm and 1 mm products, no surface swirl marks occurred in either resin. Furthermore, there was no sink mark or bulging caused by the mold back and core back, and the mold reproducibility was high with no distortion of shape. In the area with the hole marked as code number 67 (the core back structure), the cooling of the hole seemed to proceed faster, or the surrounding area was slightly less prone to foaming. Although mold number 67 has a vertical cutout mold structure, it can also be implemented with a flat cutout mold back. [Example 11]

[0271] In Example 9, the mold shown in Figure 14 was used, and the GCP apparatus shown in Figure 16 was used to similarly perform mold backing and core backing (hole number 67) at 0.5 mm and 1 mm. Even with foamed molded products with increased foaming ratio, there was no swirl marking, shrinkage, or blistering, and the mold reproducibility was high with almost no distortion of shape. We confirmed that delaying the retraction timing to 5 seconds or 10 seconds after the compressed air of the GCP process is released naturally leads to increased cooling and solidification of the molded product within the cavity, resulting in reduced mold reproducibility in both mold back and core back. The delay time varies depending on the type of resin, the type of foaming agent, the amount of foaming agent added, the type of foaming gas, the GCP pressure, and the thickness of the molded product. However, based on the inventor's experience, a delay of more than 10 seconds is not necessary to create a swirl mark.

[0272] When the molding space is filled to more than 90% with foamed resin, even if the space is evacuated, it takes time for the space to be completely evacuated. Also, there is a slight delay before the foamed gas inside the resin comes to the surface and forms swirl marks. Therefore, it is possible to obtain a clean molded product without swirl marks on the surface. In this manner, the exhaust is adjusted (set) while checking the appearance of the molded product, ranging from filling the molding space to over 90%, to complete filling, and then delaying it by about 10 seconds from complete filling. The timing of the L1, L2, and L3 exhausts can be simultaneous, or they can be set individually within the aforementioned molding process or delay time range. For simultaneous exhaust, one GCP device (as shown in Figures 15 and 16) may be used. Several devices (for example, three) may also be used. Exhaust is generally performed all at once to induce foaming, but in some cases, a flow control valve may be installed on the exhaust valve to control the exhaust speed. Vacuuming after exhausting is also possible by adding a weighted O-ring (number 42 in Figure 11) with the direction reversed {the O-ring numbered 42 (weighted O-ring in Figure 24) has a directional seal, so an additional one (not shown in Figure 12) is necessary for vacuuming}.

[0273] Immediately after exhausting the gas pressure vent (GCP), or with a slight delay, the mold is moved back. In foam molding using GCP, this can resolve the raindrop phenomenon caused by the resin filling drawing in the compressed air. By moving the mold back and opening the gas vent, the compressed air that causes raindrops by drawing in the molten resin is rapidly exhausted. The foaming force of the internal foam layer, which has not yet cooled and solidified, presses the mold down, thus reproducing the mold. In this case, raindrops do not occur, even on thin (shallow) textures or glossy surfaces. [Example 12]

[0274] (Mold temperature control) In Example 3, the mold surface temperature was set to approximately 45°C on both the fixed and movable sides for ABS, HIPS, m-PPO(E), and PP, and 55°C for PC. In Example 12, using the apparatus shown in Figure 23, glycerin was used as the heat transfer medium, and the temperature was set to 150°C on both the fixed and movable sides. GCP was performed, and then cooling water was circulated through a separate circuit installed in the mold to produce foamed molded products. As a result of setting the mold temperature high at 85°C, even with a top wall thickness of 2mm, the surface skin layer was very thin, and the internal foam layer was sufficiently foamed. The results were the same in Example 9. In Examples 10 and 11, mold reproducibility of the hole (reference number 67) was low due to mold-back and core-back, but in Example 12, the surface skin layer became very thin, so the mold reproducibility of the hole (reference number 67) was sufficiently high. In Examples 10 and 11, even with a 2mm recess and a foaming ratio of 100%, cooling and solidification were slow, so mold reproducibility was sufficient, and molded products with a good appearance could be obtained.

[0275] GCP (Gas Pressure Packing) suppresses the foaming force of the foamed resin filled in the cavity, but the gas inside the cavity is a troublesome presence that hinders the filling of the cavity with molten resin. Therefore, in foam molding using GCP, the higher the GCP pressure, the higher the mold temperature (raindrops are more likely to occur with styrene-based resins with high melt viscosity, such as PP which has a lower melt viscosity than ABS), and the higher the molten resin temperature, the more surface defects called raindrops (a phenomenon in which small depressions are created on the surface of water in a puddle when rainwater falls on it) {depressions on the surface of the molded product} become. To eliminate these surface defects, it is necessary to lower the pressure of the compressed air in the GCP, lower the mold temperature, or lower the resin temperature, but this makes it impossible to obtain the desired foamed molded product. An effective way to solve this problem is to apply a textured finish to the fixed decorative surface. There is no problem in applying it to the movable side as well. The effect of texture is that when you try to stick cooking wrap (a thin film) onto a glossy glass surface, bubbles form. However, with frosted glass, it is possible to apply it smoothly without bubbles forming. If the surface is rough, even fewer bubbles will form. If a rough texture is applied, a clean appearance without raindrops can be obtained even with foam molding using GCP. Besides texturing, the raindrop problem can also be solved by mold backing and core backing. To eliminate raindrops, the amount of mold backing or core backing is as small as 0.1 mm, and since this method does not increase the foaming ratio, there is almost no reduction in the strength of the molded product. A mold back with a flat cut in the part line of the mold is more suitable for eliminating raindrops than a core back with a vertical cut, because the compressed air that gets trapped between the resin and the mold, which causes raindrops, is rapidly exhausted. Figures 21 and 22 show molded parts with a 50 μm deep sand texture, a 20 μm deep sand texture, and a 5 μm deep textured surface. PP was used, with a GCP pressure of 1 MPa and foaming agents of 3% Wn-P-ADCA-10 and 1% Wn-P-CANa-10. Raindrops did not occur at 50 μm due to the depth of the texture, but they did occur at 20 μm. After performing a 0.1 mm mold back, raindrops were eliminated on both the 20 μm and, naturally, the 5 μm textured surfaces. Therefore, it was determined that mold back is a very effective method for solving the raindrop problem. Adding 10 wt% calcium carbonate to PP and performing a 0.1 mm mold back as described above resulted in no raindrops even on fine textures with a depth of 5 μm or less. From the results of Example 12 above, shallow texturing and mold-back processing solve the raindrop problem caused by the inability to release the compressed air trapped in the gap between the resin and the mold due to resin filling. Adding inorganic materials such as calcium carbonate, glass fibers, and glass beads to the resin also sufficiently solves the raindrop problem, but mold-back processing allows for a reduction in the amount of additives.

[0276] (Methods to eliminate raindrops on glossy surfaces) The GCP device shown in Figures 15 and 16 exhausts the compressed air inside the mold by receiving an exhaust signal from the molding machine, opening the exhaust valve (number 51), and exhausting the compressed air using its own pressure (natural exhaust, atmospheric pressure exhaust). However, as shown in Figure 49, a separate vacuum circuit (circuit with numbers 141, etc.) may be provided in addition to the exhaust valve 51, and vacuuming may be performed after exhausting. In this case, in order to fully utilize the vacuuming effect, the exhaust valve 51 should be opened first, and the mold should be opened as needed after exhausting is complete. The opening amount is the distance required to enlarge the mold (mold back, core back, recession, recess) to increase the molding space for the purpose of increasing the foaming ratio, or a small opening, for example, 0.1 mm or 0.3 mm, to enlarge the gas vent and eliminate raindrops, as described above. In this case, the PL structure may be a vertical cut (PL is a core back structure), but a horizontal cut (PL is a mold back structure) is more effective for exhausting the compressed gas between the mold surface and the molded product as the resin is drawn in during filling. After exhausting as necessary, close part number 51, open part number 141, and draw the material into the vacuumed (depressurized) tank inside part number 142. At this time, the O-ring of parting part number 33 should have a compression margin of O-long that is greater than the distance to be molded back, in order to maintain its sealing function even when the mold opens. The load-type O-ring of part number 42 used in ejector pins, etc., is directional, so when vacuuming, install it in a different direction (opposite direction) from part number 42 to enhance the vacuuming effect. The vacuuming device is shown in Figure 63.

[0277] The compressed gas used was air, nitrogen gas, carbon dioxide gas, or a 1:1 mixture of nitrogen gas and carbon dioxide gas, each compressed at a pressure of 1.4 MPa inside the sealing mold. In Example 12, using the GCP device shown in Figure 49, after exhausting the compressed gas and performing a 0.2 mm mold back, vacuuming was performed, confirming that raindrops were reduced, almost completely eliminated. The texture depth in the case of GCP was 0.5 μm, but it was confirmed that this is also possible on glossy surfaces. Higher compressed gas pressure provides a greater force to suppress the foam cells in GCP, resulting in a greater reduction in foam stripe patterns. The vacuum device is controlled by a program incorporated into the molding machine's PLC. Alternatively, a separate PLC may be installed to exchange signals with the molding machine and control the vacuum device.

[0278] This section describes specific methods for eliminating raindrops on glossy surfaces when using GCP (Glossy Plastic Coating). First, a higher mold temperature allows for a thinner non-foamed layer (skin layer) on the surface of the foamed molded product. Specifically, for amorphous materials such as ABS and HIPS, the mold temperature is raised using commercially available heat-and-cool devices, devices like the one shown in Figure 23, or by attaching a high-frequency induction coil to the removal machine to generate eddy currents on the mold surface and raise the mold surface temperature (for example, Asahi Kasei Corporation's BSM molding method). This method can be implemented with PP PC or modified PPO(E). As mentioned above, a higher mold temperature allows for a thinner skin layer, but it also increases the occurrence of raindrops compared to lower mold temperatures. As previously stated, applying a textured finish or performing a mold-back operation yields good results in eliminating raindrops. After mold-back, performing a rapid vacuum operation quickly removes the pressurized gas trapped in the gap between the mold and the resin, eliminating the compressed gas in the gap between the resin and the mold. This results in a GCP-treated foamed molded product with a beautiful, raindrop-free appearance, whether with fine textured finishes or a glossy surface. [Example 13]

[0279] We prepared two types of ABS: Clarastic GA-110G-10 (product name) from Nippon A&L Co., Ltd., which contains 10 wt% glass fiber, and Clarastic GA-110G-20 (product name) from Nippon A&L Co., Ltd., which contains 20 wt% glass fiber. When the aforementioned materials containing 10wt% and 20wt% glass fibers were molded using conventional solid molding instead of foam molding as in Example 12 (using the apparatus shown in Figure 23, the mold surface temperature was set to 150°C, which is above 125°C, considering factors such as the Vicat softening point temperature, heat deformation temperature (HDT), and load deflection temperature, since ABS is an amorphous resin and therefore does not have a glass transition temperature (Tg)), without GCP, a molded product with a very clean, highly glossy appearance was obtained, without weld lines caused by the hole indicated by reference number 67 or any floating of glass fibers. In this case, no texturing was performed on the side where the decorative surface was fixed.

[0280] When Wn-B-ADCA-10 was used as the foaming agent, and the amount added to the above resins GA-110G-10 and GA-110G-20 was set to 4 wt%, and the GCP pressure was set to 1.4 MPa, the glass fibers settled, and since the molded product was glossy, raindrops occurred. After sand texture processing with a texture depth of 50 μm and 15 μm, no raindrops caused by GCP (high pressure and large gas volume) occurred. The glass fibers sank, resulting in a clean, thin skin layer on the surface. Internally, the glass fibers acted as a foaming nucleating agent, forming a foamed layer with fine foam cells. [Example 14]

[0281] In Example 13, using the molding material and foaming agent master batch shown in Figure 42, and a foaming nucleating agent as needed, the mold surface temperature was set to, for example, 150°C, which is above the Tg of each resin, and a 50 μm texture was applied to the mold shown in Figure 14. Using the GCP apparatus shown in Figure 16, the mold back and core back were set to 2 mm. Because the mold temperature was high, even with a foaming ratio of 100%, there were no appearance defects such as raindrops, the mold reproducibility was higher compared to when the mold temperature was low, and although the skin layer thickness was very thin, there were no swirl marks on the surface. [Example 15]

[0282] (A means of suppressing one side by creating a time difference in exhaust.) In Example 3, three GCP devices shown in Figure 15 were connected to L1 to L3 of the compressed air circuit, and the pressures of L1 to L3 were set to 1.3 MPa. When the foamed resin was filled into the cavity to 95 vol%, L3 was evacuated, and when it reached 100 vol%, L2 was evacuated, a 2 mm mold back was performed, and after the mold back was completed, L1 was evacuated. Naturally, the parting of the mold opens, and at that time, the evacuation of L1 begins. Observations showed that because L1 was delayed, there was sufficient pressure on the fixed side and the mold transfer was successful. After exhausting L2, the pressing effect toward the fixed side was also confirmed by molding it back 2mm. We confirmed the effect of reducing the mold back distance by 0.1mm, 0.2mm, 0.5mm, and 1mm. We also confirmed that the raindrop phenomenon was resolved at each mold back distance. [Example 16]

[0283] In Example 3, three GCP devices as shown in Figure 16 were connected to L1 to L3 of the compressed air circuit, respectively, as shown in Figure 38. The pressure at L2 of L3 was set to 1.0 MPa, and at L1 to 1.4 MPa. When the foamed resin was filled into the cavity to 95 vol%, L3 was evacuated, and when it reached 100 vol%, L2 was evacuated. A 2 mm mold back was performed, and after the mold back was completed, L1 was evacuated. Naturally, the parting of the mold opened, and at that time, the evacuation of L1 began. Observations showed that because L1 was delayed, there was sufficient pressure on the fixed side, and the mold transfer was adequate. Similar to Example 15, it was confirmed that the mold transfer properties were sufficient and the raindrop problem could be solved even when L2 was molded back after exhaust. [Example 17]

[0284] (Manufacturing of foaming agent master batch) PC is dissolved in chlorinated organic solvents such as carbon tetrachloride, chloroform, and methylene chloride; ester-based organic solvents such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as benzene, toluene, and xylene; ketones such as acetone; and other solvents such as dimethylformamide (DMF) and diacetone alcohol. PC pellets are dissolved in these solvents (a mixed solvent of two or more types is also acceptable) to form a varnish. PC pellets and a foaming agent, such as ADCA (in powder form), are mixed in a rocking mixer, and the above varnish is added (in a rocking mixer, the varnish can be sprayed while mixing and heating, and the solvent can be evaporated). The solvent in the varnish is evaporated and allowed to dry, resulting in the foaming agent ADCA being supported around the PC pellets.

[0285] The following describes a simple manual method for manufacturing a foaming agent for PC. First, 100 grams of PC resin {Lexan 141 (trade name)} pellets were mixed with 400 milliliters of ethyl acetate. After standing at room temperature for 24 hours, the mixture was heated to 45 degrees Celsius, stirred, and the PC was dissolved in ethyl acetate to obtain PC varnish. 500 grams of Lexan 141 pellets and 50 grams of ADCA powder were placed in a Teflon-coated frying pan and mixed. The PC varnish was then added little by little while stirring with a spatula, so that the ADCA was supported around the PC pellets. The frying pan was slightly heated to about 40°C to 60°C to accelerate the evaporation of the ethyl acetate solvent. The ethyl acetate was evaporated and dried to support the ADCA on the PC. If the pellets were stuck together, they were crushed using a wooden hammer or similar tool. In this way, a master batch of foaming agent for PC (PC001) was obtained.

[0286] PC001 was added to 40 pellets of Lexan 141 in a ratio of 1 (resulting in an ADCA of 1 ÷ 45 × 0.01 = 0.025 wt%) using a tumbler, and foam molding was performed using a 350-ton injection molding machine. Since GCP was not performed, swirl marks occurred on the surface, but a foamed structure with discontinuous foam cells inside was obtained.

[0287] In the foam molding process described above, using the GCP apparatus of the present invention (Figures 9, 15, 16, 38, etc.), the seal mold shown in Figures 10 to 14 was pre-pressurized with air at a pressure of 1.4 MPa, and then filled with foamed resin imparted with foaming agent PC001 to obtain a foamed structure with a smooth skin layer on the surface and fine foam cells inside.

[0288] In the case of ADCA, thermal decomposition generates foaming gases such as nitrogen, carbon monoxide, and carbon dioxide, but also produces a small amount of ammonia gas. Since ammonia gas is alkaline and there is a risk of it decomposing PC, a small amount of organic acid such as citric acid is added to react with and neutralize the ammonia. Since these organic acids are also in powder form, they can be supported around the PC pellets, similar to PC001, and used as a citric acid masterbatch. ADCA produces nitrogen gas, which has low solubility in resin, resulting in larger foaming cells. Since zinc oxide, calcium carbonate, calcium sulfate, and barium sulfate are also in powder form, they are similarly supported on PC pellets to produce a master batch of foaming agents for use. These can be mixed together beforehand and supported around the PC pellets, but if the proportions need to be changed depending on the molded product, it is best to manufacture separate master batches of foaming agents, decomposition accelerators, organic acids, and foam nucleating agents, and then mix the master batches with each of these supported on them before molding.

[0289] The above description of foaming agents for PC involves supporting them on PC pellets, but it is also possible to manufacture konpeito (sugar candy) by adding PC varnish to ADCA powder while stirring, without using PC pellets. In this manufacturing method, the concentration of ADCA per pellet is high, making it difficult to control the foaming force. When it is necessary to subtly adjust the amount of foaming agent added (meaning adjusting the foaming force), an amount of around 5 wt% to 20 wt% per PC pellet is generally practical.

[0290] There are many polymer alloys with PC as the main component, such as PC / ABS, PC / PET, and PC / PBT. The master batches of foaming agents, foaming aids, and foam nucleating agents for PC can be those intended for PC. Of course, pellets of alloys such as ABS, PET, and PBT can also be used, but since these PC polymer alloys, which have PC as their main component, have a sea-island structure, if a resin that forms the "sea" is used, the carrier resin of the master batch can be easily dispersed into the main component resin of the molded product simply by melting and kneading it with a short-shaft screw in the injection molding machine.

[0291] As mentioned above, PC can be dissolved in various solvents, but after dissolving PC, a composite solvent can be formed using aromatic hydrocarbons, alcohols, etc., for viscosity adjustment. In this Example 17, a foamed structure having an internal foamed layer and an external skin layer can be obtained using the GCP method of the present invention, whether using the inorganic foaming agent sodium bicarbonate or the organic foaming agent ADCA. However, the resulting foamed structure shows a significant decrease in physical properties regardless of which foaming agent is used. As mentioned above, hydrolysis of PC (polycarbonate) significantly degrades its physical properties, so a liquid foaming agent such as ethanol is ideal for PC. By placing dry ice pellets into the plasticized molten PC resin and dispersing the dry ice as gaseous carbon dioxide using the temperature of the heating cylinder and the temperature of the molten PC (heat, thermal energy), the problem of hydrolysis caused by the foaming agent is solved. This foamed molded product has no foaming residue, so there are no problems like those that occur when baking soda is used, making it suitable for painting.

[0292] Using the method of Example 17, a masterbatch of colorants for PC can be manufactured by supporting pigments for PC with PC as a carrier resin. By supporting carbon black, kicken black, acetylene black, carbon fiber, and CNTs (carbon nanotubes), a masterbatch of additives that impart conductivity to PC can be manufactured. This support method does not require melt mixing, so it can be easily manufactured even if the melting temperature of the carrier resin is high, and it is not limited to the manufacture of foaming agents for PC.

[0293] Example 17 illustrates a method for producing foaming agents for PC (polycarbonate). In addition to PC varnish, an aqueous solution of polyvinyl alcohol (PVA) can also be used. Granulation may also be performed using a low-melting-point resin, such as caprolactone powder. This method can be applied to other materials besides PC, such as ABS, HIPS, and PP, and is not limited to PC. [Example 18]

[0294] (Manufacturing of foaming agent master batch for PP) In Example 1, a method for manufacturing a master batch of foaming agent for PP was described. Maleic acid-modified PP can be used as the material supporting the PP resin pellets, and as an example, {ARROWBASE DB-4010 (product name)} manufactured by Unitika Ltd. can also be used. In addition, Toyobo's PMA H1100P, PMA-F6, and NZ-1015 can also be used. NZ-1015 is an emulsion type and does not contain emulsifiers, making it easy to use. In practice, these maleic acid-modified PPs were used to manufacture master batches of foaming agents and foam nucleating agents on PP pellets using ADCA, sodium bicarbonate, potassium bicarbonate, monosodium citrate, etc. Hardlen NZ-1015 is an emulsion type, so there is little risk of fire when heated. The manufacturing (supporting) of these foaming agents, etc., was as shown in Example 1. In Example 18, instead of H processing, a liquid-adding type and heating type of rocking mixer (product name) from Aichi Electric Co., Ltd. were used. Production was carried out using a machine (such as a rocking mixer) that has the function of heating from the outside to evaporate water and solvents, and the function of spraying (adding liquid) varnish, etc., used for the support into the material. The melting temperature of the maleic acid-modified PP should preferably be close to that of the PP to be molded, but it is acceptable for it to melt in the heating cylinder of the molding machine, and then melt during the weighing and melt-kneading stages, and become compatible (dissolve) in the PP. Furthermore, each master batch of the foaming agent of the present invention can be used not only by injection molding, but also by extrusion molding and block molding. Furthermore, this foaming agent master batch can also be used with PP polymer alloys such as PP / PA (where PA is made of nylon 6, nylon 6-6, nylon 12, aromatic nylon, etc.). By suspending ADCA in the aforementioned Arrow Base DB-4010, it can be supported on the surface of PP pellets, thus creating a foaming agent masterbatch. Similarly, by dissolving baking soda in Arrow Base DB-4010, spraying it onto the surface of PP, heating it, and drying it, a foaming agent masterbatch can be created. [Example 19]

[0295] {Manufacturing of foaming agent masterbatches for ABS, HIPS, and modified PPO(E)} In Example 17, a method for manufacturing a master batch of foaming agent for PC was described. A foaming agent master batch for ABS can be manufactured by using a varnish obtained by dissolving ABS or AS in MEK, and then supporting the ABS or AS resin pellets to be molded with an inorganic and / or organic foaming agent. Similarly, foaming agent master batches for HIPS, PS, and modified PPO(E) can be manufactured by dissolving HIPS and PS in MEK and supporting the HIPS or PS resin pellets with an inorganic and / or organic foaming agent. Of course, the manufacture of these master batches was also possible using H processing and the rocking mixer shown in Example 18. Embodiment 1

[0296] In Embodiment 1, as described above, the master batch of the foaming agent is manufactured by separately producing a master batch of the foaming agent, a master batch of the foaming agent, and a master batch of the foaming agent by supporting the foaming agent, foaming aid, and foaming nucleating agent on a resin that is compatible (solubilable) with the resin to be blended. By mixing the resin pellets to be blended with each of these master batches, it is possible to produce foam cells of the desired optimal foaming ratio, optimal foam structure, and optimal size. For example, the melting point of ABS is 240°C, and the thermal decomposition temperature of ADCA is approximately 230°C (it decomposes at a melting point of 225°C). Since the molten resin temperature and the thermal decomposition temperature of ADCA are close, a masterbatch of foaming agent supported by ADCA alone is sufficient. However, in the case of PP, the melting point is low at 200°C, so mixing in a masterbatch supported by urea, which has the effect of lowering the thermal decomposition temperature of ADCA, can lower the thermal decomposition temperature of ADCA.

[0297] Bicarbonates such as baking soda, citric acid, and sodium dihydrogen citrate can be prepared as aqueous solutions. These aqueous solutions can be placed in a Henschel mixer, for example, and heated while rotating the vessel at a temperature below the decomposition point of these substances (those acting as foaming agents), allowing them to evaporate to dryness. This process granulates the material to a size that mixes well with resin pellets for molding, making it easier to handle than powders. A rocking mixer can be used instead of a Henschel mixer.

[0298] As explained in the above examples, since ADCA is poorly soluble, granulating ADCA powder and the varnish of the resin to be blended {for example, a MEK solution of PS (PS doped cement), a MEK solution of AS (AS doped cement)} in a Henschel mixer, as in the case of bicarbonates, can produce a foaming agent mainly composed of ADCA.

[0299] Stearic acid compounds, such as stearic acid, magnesium stearate, and zinc stearate, may be dissolved in a solvent such as toluene and used as a substitute for the doped cement. In this case, since stearic acid and stearic acid compounds are widely used as lubricants in molding processes, they may also be used during the granulation of foaming agents for PP. PVA can also be used.

[0300] The aforementioned solution of stearic acid, a stearic acid compound such as toluene, PP pellets, and an inorganic blowing agent such as sodium bicarbonate or an organic blowing agent such as ADCA in powder form may be placed in a Henschel mixer and granulated. Maleic acid-modified PP may be used, or maleic acid-modified PP may be used in combination with the aforementioned solution of stearic acid, a stearic acid compound such as toluene, etc. Embodiment 2

[0301] In Embodiment 1, or when ADCA is used as a foaming agent, the foam cells formed are large. If pellets supported with sodium dihydrogen citrate, pellets supported with zinc oxide, etc., are used as foaming nucleating agents by mixing them with pellets supported with ADCA and pellets of the resin to be blended, fine foam cells can be obtained through the action of the foaming nucleating agent. Embodiment 3

[0302] When foam molding is performed using pellets supported with sodium bicarbonate, fine foam cells are obtained. However, as shown in Example 7, the foam residue (sodium carbonate) affects the adhesion of the coating film. By adding a master batch on which sodium bicarbonate, a foaming agent, and citric acid, which reacts with the sodium carbonate foam residue, are supported on pellets, the generation of foaming gas through a chemical reaction with sodium bicarbonate and the reaction of sodium carbonate foam residue with citric acid, which affects the adhesion of the coating film, reduce the amount of foam residue that reduces the adhesion of the coating film, thereby improving the adhesion of the coating film. Embodiment 4

[0303] In Embodiment 2, sodium dihydrogen carbonate was used as the foaming agent, but it has been confirmed that potassium dihydrogen carbonate also has a similar effect in making foam cells finer. Of course, in Embodiments 1 to 3 and Embodiment 4, if GCP is performed using the mold shown in Figures 10 and 11 and the GCP apparatus shown in Figures 15, 16, and 9, a foamed molded product with a clean appearance without swirl marks on the surface and containing foam cells inside can be obtained. Embodiment 5

[0304] Masterbatches of foaming agents, foaming aids, and foam nucleating agents used in foam molding of PP extrusion are manufactured by supporting a PP-compatible PP base resin with maleic acid-modified PP that is also compatible with PP. Therefore, even in PP extrusion molding, the PE does not appear on the surface, as shown in Figures 1 and 2, unlike the masterbatches of commercially available foaming agents that use a PE base resin. These masterbatches of foaming agents, foaming aids, and foam nucleating agents are manufactured separately and mixed with PP pellets in the optimal proportions. This can also be done with PP / PA polymer alloys. Embodiment 6

[0305] In the case of foam molding of PC, commercially available foaming agents use ABS, which is compatible with PC, as the base resin. As a result, foamed molded products obtained by foam molding of PC inevitably contain a certain amount of ABS, which reduces the properties of PC (such as high impact resistance). To solve this problem, if a foaming agent is supported on PC using a solution obtained by dissolving PC in an organic solvent, and a master batch of the manufactured foaming agent is used, the aforementioned problem of reduced physical properties is solved. In this case, as shown in Example 17, PC with improved solvent solubility can be used in addition to general PC, but a varnish using styrene-modified acrylic resin may be used in addition to the dissolved PC. However, in this case, as mentioned above, a reduction in the physical properties of PC due to inorganic and organic foaming agents is unavoidable. Embodiment 7

[0306] In methods such as MuCell, gas is used as a foaming agent in injection molding machines and extrusion molding machines. As a result, in the case of in-line injection molding machines, (1) the amount of gas injected is controlled by pressure control, which changes the pressure of the molten resin during metering. Consequently, the amount of gas that imparts foaming properties to the molten resin entering the heating cylinder changes. As a result, variations occur in foaming, foaming force, and foaming properties. (2) Although molten resin is not a liquid, if we consider the molten resin in Embodiment 7 of the present invention as a "liquid" in relation to Embodiment 7, it is extremely difficult to pressurize and dissolve gas in the molten resin in the heating cylinder and / or finely disperse it in a short time {during the time between metering (plasticization and melting / kneading)}. If the gas is injected or extruded in a large mass without fine dispersion, it will swell and burst. (3) In the case of an injection molding machine, the heated and molten resin moves to the front of the heating cylinder (imagine the screw as the bolt and the heated and molten resin as the nut; as the bolt rotates, the nut moves forward). It is difficult to introduce gas into the heating cylinder and finely disperse it during metering to impart foaming properties in this short time, especially for large molded products (molded products with high weight).

[0307] This problem can be solved by using a pre-plunger type injection molding machine, such as in the UCC (Union Carbide Method for Foam Molding) method. Instead of a pre-plunger type injection molding machine, it is preferable to pre-disperse gas in a small heating cylinder with a small screw, for example, at the top of the injection molding machine's heating cylinder, to impart foaming properties to the molten resin, and then send it to the main heating cylinder where injection takes place, where it is re-mixed and finely dispersed. This type of specification and usage can be achieved using a pre-plasticized injection molding machine manufactured by Sodick Co., Ltd.

[0308] The above example described gases, but it is not limited to gases; liquids (such as ethanol, water, or sodium bicarbonate solution) can also be used. In this case, the injection volume is controlled not by gas pressure, but by a syringe (plunger, piston and cylinder, etc.). Whether it's a gaseous or liquid substance, or of course a solid such as a physical blowing agent like microballoons, or a chemical blowing agent like baking soda or ADCA, if you use the mold structure shown in Figures 10, 11, and 37 of the present invention and perform GCP using the apparatus shown in Figures 15 and 16, you can obtain molded products with a clean appearance free of swirl marks on the surface.

[0309] Similarly, in the case of an extrusion molding machine, a small sub-plasticizing heating cylinder is installed, for example, above the main heating cylinder, and gas or liquid is introduced into it to impart foaming properties. In the case of an extrusion molding machine, even if gas is directly introduced into the extruder heating cylinder, dispersion will still be poor. Therefore, similar to the case of an injection molding machine, it is better to introduce gas into a small sub-heating cylinder (screw) for pre-melting, pre-disperse it in the molten resin to impart foaming properties, and then send it into the main heating cylinder of the extruder, where it is re-kneaded and finely dispersed to extrude the foamed resin. Embodiment 8

[0310] This section describes a specific method for performing foam molding using an injection molding machine (which in this invention is also simply referred to as a "molding machine"), including the program to be incorporated into the molding machine. The sealing mold shown in Figure 10 (seal mold with ejector box structure) or Figure 11 (mold in which the ejector pin is sealed using a weighted O-ring, such as those shown in Figures 24 and 25) is mounted (installed) into the molding machine. A foamable resin (a mixture of the pellets to be foamed and the pellets of the foaming agent masterbatch) is prepared by first mixing the foaming agent masterbatch (a form in which the foaming agent is kneaded into the resin) with a foaming agent masterbatch (a form in which the foaming agent is kneaded into the resin) manufactured and sold by companies such as Eiwa Chemical Industries, Ltd., Sankyo Chemicals, and Otsuka Chemical Co., Ltd., using a tumbler or an auto coloring device manufactured and sold by companies such as Kawata Co., Ltd., in an optimal ratio (determined by the size and shape of the foaming cells, for example, by suppressing swirl marks with the pressure of the GCP device shown in Figures 15 and 16) into the hopper of a molding machine. For small quantities, the foaming agent powder may be supported on the surface of the pellets to be molded using oil or the like.

[0311] (Timing of pressurization) Once the molds shown in Figures 10 and 11 are closed (the mold clamping completion signal may also be the signal from a limit switch (LS) installed on the mold's PL), and nozzle contact is complete, the molding machine (by command from the program built into the molding machine's PLC (sequencer)) opens, for example, the valve (number 46) of the GCP device connected to Figure 16, to introduce GCP gas into the spaces inside the mold (L1, L2, L3) (compressing, pre-pressurizing, applying GCP), thereby pressurizing (compressing, pre-pressurizing) the spaces inside the mold. The pressurization time is determined by a value (time) pre-programmed into the molding machine's PLC (also simply called PLC). When the pressurized time reaches this value, or when a pressure gauge with contacts (number 56) reaches a pre-set pressure, injection of foamed resin into the molding space begins. The molding machine and the GCP device are connected by a signal cable, and they exchange signals (for confirmation and commands, etc.).

[0312] The foaming agent is heated and melted in the heating cylinder, and the foaming agent undergoes thermal decomposition and chemical reaction due to the temperature (thermal energy) inside the heating cylinder and the temperature (thermal energy) of the heated and molten resin. The foaming gas generated is then pressurized, dissolved, and finely dispersed in the molten resin by the rotational force (melt mixing force) of a screw installed inside the heating cylinder, thereby imparting foaming properties to the foamed resin, which is then filled (injected) into the molding space (L2). At this time, valve 46 is still open, so pressurized air continues to be supplied to the spaces inside the mold (L1, L2, L3).

[0313] The compressed gas inside L2 is pushed out to L1 and L3 through gaps in the nesting structure and ejector pins by the force of the foamed resin filling. In the case of Figure 10, this compressed air enters the ejector box, which acts as a cushion and prevents the pressure from becoming excessive, thus reducing discoloration and burning of the resin. In the case of Figure 11, there is not enough space for the ejector box to function, so it is preferable to connect the GCP device to one equipped with sub-tank number 55 as shown in Figure 16. Of course, it can also be done in Figure 15. The reason is that the space of the hose connecting the GCP device and the mold in Figure 15 serves to some extent as sub-tank number 55.

[0314] (Timing of exhaust) During the filling of foamed resin into L2, immediately after filling is complete, and a short time after filling is complete, the injection valve labeled 46 is closed and the exhaust valve labeled 51 is opened (sometimes the timing of opening valve 51 is slightly delayed after closing valve 46), thereby exhausting the compressed air inside the sealing mold. The timing of exhaust is set as a percentage, with the time when the molding machine starts filling the molding space (injection start) being 0 and the time when filling is complete being 100. (Exhaust during filling) The screw position can be monitored with a servo motor, magnetar scale, encoder, etc., so the position can be set arbitrarily, and an exhaust signal should be output when the screw reaches the set position.

[0315] After injection is complete, exhaust is controlled using the molding machine's filling completion signal (temporary pressure completion signal). In foam molding, holding pressure is sometimes applied without using a cushion. This is because without holding pressure, the springiness (compressibility) of the foamed resin filling the molding space causes the screw to return, resulting in less variation in the weight of the molded product. The pressure and time of holding pressure do not need to be very high or long, as long as the screw does not need to return. Of course, sometimes holding pressure is applied without a cushion.

[0316] (Exhaust timing, suckback) There are two timings for exhausting the compressed air inside the mold: exhaust during injection and exhaust after filling is complete. For exhaust during injection, the molding machine's PLC monitors the position of the injection screw, so an arbitrary screw position {exhaust position = position (numerical value) where it is confirmed that the screw has passed a preset position} is input to the PLC, and when the screw reaches that position, an exhaust signal is output to the GCP device in Figure 15 or Figure 16, opening the exhaust valve 51 and releasing the air. When exhausting after injection is complete, exhaust can be performed immediately after injection is complete (simultaneously), after a certain period of time has elapsed, or after injection is complete, to reduce the pressure on the foamed resin filling the molding space, by sucking back (screw retraction) and then exhausting immediately when sucking back begins, during sucking back (position pre-entered in the exhaust command), immediately after sucking back is complete, or after sucking back is complete and a certain period of time has elapsed. These exhaust commands are performed by a program built into the molding machine's PLC.

[0317] While difficult with the spring-type shut-off nozzles of Fiser Co., Ltd., it is perfectly feasible with needle-type or rotary valve-type shut-off nozzles using hydraulic or pneumatic cylinders. Suck-back and GCP exhaust are performed separately, and the timing combinations described above are flexible. Suck-back commands are given by a program built into the molding machine's PLC. Similarly, in the case of hot runners, the spring-type devices manufactured and sold by Feeser Co., Ltd. cannot be used, but devices that open and close using hydraulics, pneumatics, actuators, etc., can be operated in the same way as the needle-type shut-off nozzles mentioned above.

[0318] (Expansion Core) When using a means that has the same action and effect as the aforementioned suck-back (referred to as an expansion core or breathing core in this invention), which involves retracting (expanding) a part of the mold to reduce the pressure of the foamed resin filled in the molding space and facilitate foaming, the timing of exhaust is set in the same way as the aforementioned suck-back. Suck-back and expansion core may be performed simultaneously in the same mold. In that case, the decision of which operation to use for exhaust is made by observing the state of the molded product. The expansion core initially compresses a portion of the mold, and then uses hydraulic or pneumatically operated cylinders, servo motors, and other actuators to retract a portion of the operating core.

[0319] (Mold with shutter) A dummy shape is provided in part of the mold, and a shutter is installed at the entrance. Initially, the shutter is closed and foaming resin is filled into the molding space. When the shutter is opened at the appropriate time, the foaming resin flows into the unfilled space, reducing the pressure of the foaming resin already filled in the molding space, thus facilitating foaming. The timing for opening the shutter is the same as in suck-back, and the operation is controlled by a program programmed into the molding machine. The expansion core, in addition to having a drive mechanism inside or outside the mold for opening and closing the shutter, uses a mechanism that operates the molding machine's ejector. Besides the ejector plate incorporating the ejector pins of the mechanism that pushes out the molded product, another ejector plate (one set) is placed in front of it, and a stepped ejector rod is attached to it. This allows for the operation of the expansion core and the opening and closing of the shutter, separate from the operation of the ejector pins (which can push out the ejector plate at the front and the conventional ejector plate incorporating the ejector pins). Naturally, these commands (such as opening and closing the shutter) are performed by a program built into the molding machine's PLC.

[0320] (Molded back, core back) In the case of mold-back and core-back (collectively referred to as mold-back, etc.), mold-back is usually started when exhaust is complete, but it may also be started during exhaust. In this case, the pressure at which mold-back will be started is pre-set on pressure gauge number 56, and mold-back is started when the pressure drops to the set level. Similar to suck-back, a delay time may also be set for starting mold-back. Naturally, these commands are issued by a program built into the molding machine's PLC.

[0321] The purpose of mold-back is to increase the foaming ratio. When using the GCP of the present invention to eliminate surface swirl marks and obtain a smooth and beautiful molded product, and when increasing the foaming ratio by a significant amount (about 2 times), mold-back (Figures 19 and 20) is preferable to core-back (Figures 17 and 18). The timing of mold-back is not before the GCP, but rather when the exhaust of the GCP begins and the pressure gauge labeled 56 reaches the set pressure, or when the exhaust of the GCP is complete (when the pressure gauge labeled 56 shows a pressure close to atmospheric pressure), or a delay time is set from the time the GCP is exhausted and the pressure gauge labeled 56 reaches the set pressure, and mold-back is started when the set delay time is reached. Naturally, these commands (for mold-back, etc.) are performed by a program built into the PLC of the molding machine. When a mold back is performed, the width of the PL gas vent (sometimes part number 131 widens. At the same time, the PL opens up all around by the distance the mold has been moved back, making the gas vent larger) widens. As a result, a small amount of compressed gas that would otherwise enter the gap between the mold and the resin and cause raindrops is suddenly exhausted. However, the inside of the filled foamed resin has not yet cooled and solidified completely and still retains its foaming properties, so it is transferred back to the mold, resulting in a foamed molded product with a clean appearance without raindrops.

[0322] As described above, raindrops can be eliminated by performing mold-back, but the inventor's diligent research has revealed that even a shallow textured finish is better than a glossy finish. Combining GCP with vacuuming is highly effective. When mold-back begins, connecting L1 to L3 of the mold space with a hose and rapidly reducing the pressure using a vacuuming device (Figure 63) at the end of the hose eliminates raindrops on the glossy surface, resulting in a foamed molded product with a beautiful appearance. The molds used are the sealing molds shown in Figures 10 and 11. To fully utilize the vacuuming function and effect, a structure that seals the ejector pins, which have a small volume of space for vacuuming, is preferable. In Figure 11, the O-ring sealing the ejector pins has directionality, so even when vacuuming is performed on the mold, the same seal is used in the opposite direction, preventing air from entering. To enable vacuuming even when the PL opens after mold backing, a thicker seal (33) or the seals shown in Figures 56 to 62 should be used so that the sealing performance is maintained even when the PL opens. Simply connecting a vacuum pump to the mold or to the GCP device shown in Figures 15 and 16 will not allow for a rapid depressurization. It is preferable to connect the vacuum pump (number 177) to the receiver tank (number 169), depressurize the inside of the receiver tank, and then open the valve (number 174) in response to a signal from the molding machine to rapidly create a vacuum.

[0323] When using GCP to form a smooth skin layer on the surface of a foamed molded product, the layer will be thinner if the mold surface temperature is high. For example, the mold surface temperature can be increased using a device like the one shown in Figure 23. Alternatively, the mold surface can be heated using high-frequency induction heating. However, in this case, the high mold surface temperature will result in a lot of raindrops. To eliminate raindrops and obtain a smooth foamed molded product, using a mold back and sufficient vacuuming will produce a molded product with a smooth appearance and no raindrops, even on a glossy surface. Thus, by using high temperatures for both the foamed resin and the mold surface, performing GCP, and then vacuuming, it is possible to produce foamed molded products with thin walls and smooth surfaces.

[0324] (Vacuuming) When vacuuming the mold (more precisely, reducing the pressure) using the vacuum device shown in Figure 63 after mold-back, etc., this should be done after the exhaust of the GCP is complete. From the molding machine PLC, after mold-back, etc. is complete, open part number 174 and draw some of the pressurized gas remaining in the mold into part number 169. Opening part number 174 should be done simultaneously with the completion of mold-back, etc., or after a set delay time has been completed. The pressure gauge on part number 170 has a function to output the pressure value as needed, and the molding machine PLC will not start clamping the mold until the pressure has been reduced (vacuumed) to below the set value. To fully realize the effect of vacuuming, a mold with sealed ejector pins (smaller pressurized volume) as shown in Figure 11 is better than a mold with an ejector box specification (larger pressurized volume) as shown in Figure 10. In some cases, after vacuuming, the mold is clamped again (at a distance less than, the same as, or greater than, the distance at which the mold was initially pressed back) and then compression molded.

[0325] (O-GCP, I-GCP) The GCP apparatus in Figures 15 and 16 illustrates a method for suppressing foaming and eliminating surface swirl marks by applying pressure (pressurization) with gas from outside the foamed resin. The inventor refers to this as "Outer GCP (O-GCP)". When hollow molding, exemplified by Asahi Kasei Corporation's AGI and Mitsubishi Gas Chemical's Simpress, is applied to the foamed resin of the present invention, foaming is suppressed from within the molded product and from the hollow portion formed inside the molded product. For example, the apparatus in Figure 1 described in the patent specification of application number PCT2016-86380 (hereinafter referred to as "the 86380 patent") and the compressed high-pressure gas in Figure 1 are installed in the mold in Figures 10 and 11 of the present invention, along with a hollow molding pin (a pin that introduces high-pressure gas into the molded product) such as Figure 124. By using Figures 1 and 124 described in the specification of these 86380 patents to create a hollow interior and then exhausting the gas used to form the hollow, the gas pressure that suppresses foaming from the inside is released, and foaming begins in the newly hollowed-out area. The inventor calls this "Inner GCP (I-GCP)".

[0326] I-GCP may be linked (synchronized) with O-GCP, but it is not required. I-GCP can be started (injection of high-pressure gas into the molded product) during injection, immediately after filling is complete, after a delay time has passed since filling is complete, at the start of suck-back, during suck-back, immediately after suck-back is complete, or after a delay time has passed since suck-back is complete. I-GCP forms a hollow section, and exhaust is performed immediately after the injection of high-pressure gas, or after a certain delay time has passed. The following describes the program in the molding machine PLC. After applying O-GCP to the molding space in advance, the foamed resin is injected. During injection, simultaneously with the completion of injection, or after a certain delay time has passed since the completion of injection, the valve numbered 14 in Figure 1 of Patent 86380 is opened to form a hollow section inside. If necessary, valve number 14 in Figure 1 of patent 86380 is closed to contain the high-pressure gas injected inside (holding time). Then, valve number 15 in Figure 1 of patent 86380 is opened to release the high-pressure gas, and foaming will begin towards the hollow interior. When the program incorporated into the molding machine PLC for I-GCP is used with non-foaming resin, it can be used as a program for hollow molding. O-GCP is controlled by a program incorporated into the molding machine PLC as described above.

[0327] The gas injection pin shown in Figure 124 of the 86380 patent used in I-GCP may be fixed, but to ensure smooth exhaust, a hydraulic or pneumatic cylinder should be provided at the rear, and the pin should be moved forward before high-pressure gas injection. When exhausting (opening and starting the exhaust of the high-pressure gas inside, as shown in Figure 1 of the 86380 patent, either simultaneously or after a certain delay), the pin should be moved back to release the pressure inside the hollow section; otherwise, it will swell and rupture during demolding. Embodiment 9

[0328] (Gasic and liquid foaming agents) Embodiment 8 mainly described the case in which a masterbatch supporting a solid chemical blowing agent was used, but the method can also be carried out using a gas or liquid blowing agent. When injecting gases such as nitrogen gas and carbon dioxide, or liquids such as water, alcohol, and sodium bicarbonate solution into the heating cylinder of a molding machine during metering to impart foaming properties to a resin being plasticized, the program in the molding machine's PLC sends a signal at the start of metering, or after a delay time from the start of metering, or after pre-entering the screw position, the injection of gas or liquid begins when the screw passes that position during metering. To stop the injection of gas or liquid, a signal is sent when metering is complete, or after a predetermined time has passed from the start of metering, or after pre-entering the screw position, a command to stop injection is output. Embodiment 10

[0329] The gas used in GCP is generally air, but if discoloration or burning occurs, nitrogen gas, carbon dioxide, etc., can be used. Alternatively, a gas mixture may be used. Figures 15 and 16 show separate openings (not shown) and separate valves (not shown). By compressing the inside of the mold with initial air and then compressing L2 with air at a pressure higher than the initial compressed air pressure, the inside of L2 can be replaced with an inert gas such as nitrogen gas or carbon dioxide. These inert gases may also be used from the beginning. Needless to say, these are also incorporated into the molding machine's program. Embodiment 11

[0330] The aforementioned Shinbo method can also be applied to the O-GCP and I-GCP methods described above. The molding machine program also incorporates a command to induce foaming by simultaneously injecting liquid foaming agent through an injection port located at the rear of the nozzle. Of course, experiments have confirmed that using GCP in conjunction with this method results in molded products with a clean appearance.

[0331] The above-described examples and embodiments are illustrative for illustrative purposes only and do not constitute the present invention. Modifications and additions are permitted as long as they do not contradict the technical idea of ​​the present invention as can be understood by the parties from the claims, detailed description of the invention, and drawings. [Industrial applicability]

[0332] This method is applicable to the manufacture of foamed molded products of thermoplastic resins, particularly those with a clean appearance free from swirl marks and with a high foaming ratio.

[0333] This document shows structural diagrams of the mold used in the present invention, structural diagrams of the GCP equipment, diagrams (photographs) showing the results of the implementation, and diagrams (tables) showing the results of painting and other processes. [Explanation of Symbols]

[0334] 1. Gate 2. Silver streaks caused by PE occurring near the gate. 3. The swirl marks in the distance of the gate are suppressed, indicating that the exterior is clean. 4. Swirl marks on the surface 5. Top stopper 6. Space (space under pressure) 7. Sparkling water 8. Container 9. Partition 10. Space 11. Door 12. Surface bubbles 13. Beer (contains carbon dioxide) 14. Cup 15. No bubbles are present on the surface. 16. Spool bushing 17. Mounting plate on the fixed side 18. Template for housing the fixed insert. 19. Fixed side insert 20. Maturing surface of the fixed insert 21. Molding space (mold cavity, cavity, molding space, L2) 22. Template for housing the movable insert. 23. Insert on the movable side 24. Ejector pin (abbreviation: EP) 25. Ejector plate (top) 26. Ejector plate (bottom) 27. Spacer block with sealing function 28. Mounting plate on the movable side 29. Lot holes 30. The mating surface of the movable insert. 31. O-ring 32. O-ring 33. O-ring 34. Ejector mechanism 35. O-ring 36. O-ring 37. Spacer Block 38. O-ring 39. Ant groove 40. Plate (top) 41. Plate (bottom) 42. O-ring 43. Compressor {with receiver tank (not shown)} 44. Hose 45. Connection between manifold 49 and injection valve 46 46. ​​Injection (compressed air) valve 47. Arrow indicating the direction of exhaust of GCP (gas (compressed gas) injected into the mold) 48. Kapla 49. Manifold 50. Connection between manifold 49 and exhaust valve 51 51. Exhaust valve 52. Flexible hose 53. Arrows indicating the flow direction of GCP (gas pressurized inside the mold) from the compressor, and arrows indicating the flow of gas from the compressor to the GCP device. 54. Arrows indicating the inflow and outflow of compressed air into the mold. 55. Sub-tank 56. Pressure gauge 57. Piping connecting to sub-tank 55 58. Check valve 59. Fixed mold 60. Parting line (PL) 61. The movable mold 62. Vertical parting lines {Vertical parting lines between metal parts (fixed and movable molds)} 63. Arrow indicating core back (arrow indicating that 61 has been moved backward) 64. Flat parting 65. Arrow indicating mold back (arrow indicating that 61 has been moved back) 66. Gap resulting from parting line opening due to mold backing. 67. Core-back structure; indicates that the parting line has been opened by the core-back. 68. Mold-back structure (single-sided engraving) 69. Molded back structure (engraved on both sides) 70.Tenniku 71.Heating medium 72.Magnetic material 73. IH heater coil 74. Feather 75. Magnets 76. Magnets 77. Flow control valve 78. Arrows indicating the direction of flow 79. Inserts for molds 80. Filter 81.Heating device 82.Circulation device 83. Piping 84. For the sealing portion of load-type O-rings, materials such as Turcon (product name) and Zarcon (product name) are mainly used. 85. In a weighted O-ring, part number 84 is the component that applies load, and a U-shaped stainless steel spring is fitted into part number 84 with its opening facing upwards. 86. The opening of a U-shaped stainless steel spring, designated as part number 85, is fitted downwards for the purpose of applying the load. The material is not limited to stainless steel; spring steel may also be used, and the shape may be that of a coil spring as shown in Figure 29. The load-bearing object does not have to be metal; a commercially available O-ring as exemplified in Figure 30 may also be used. 87. The lip (seal) portion of the U(V) shaped O-ring (packing) has the same function as part number 84, as illustrated in Figures 24 to 26. 88. The internal U(V) shape (recess) is shown. When Figures 29 and 30 are fitted into part number 88, it becomes a load-type O-ring. 89. Gas pressurizing pins installed in the mold 90. Gas circuit for gas pressurization 91. Gas pressurized pin with double-layered ejector pin 92. Gas circuit for gas pressurization 93. Gas pressurizing pin installed on the mounting plate on the movable side 94. Gas pressurized pin with double-layered ejector pin 95. Outer cylinder of the gas pressurizing pin; the dashed line indicates the hole drilled inside the ejector sleeve pin. 96. Ejector pin 97. D-cut, processed to facilitate gas flow. 98. Rubber sheet (gasket) for sealing gas 99. Pressurized gas 100. Gas emission point (tip of the gas pin) 101. Ribs installed to prevent gas leakage 102. Cross-section of a molded product 103. Gas pressure pin 104. Applying a rough texture to the gas-pressurized surface makes it easier for gas to enter the gap between the resin and the mold due to the wedge effect. 105. The mold on the movable side 106. Fixed mold 107. A gas pressure pin 103 is fixed to the movable mounting plate 28 to provide a 94 gas circuit. 108. Inlet for gas used in compressed air 109. One side 110. Foam layer trapped inside by GCP 111. The outer skin layer formed by GCP is smooth. 112. Main body of the L-shaped sticker 113. O Limb 114. Housing for the L-shaped sticker 115. O-rings fitted for load-bearing purposes 116. The upper part of the retaining block 117. The (bottom) of the retaining block 118. O-ring 119. O-ring 120. Coupler 121. Piping 122. Devices that perform GCP to L3 123. Equipment for performing GCP to L2 124. Equipment for performing GCP to L1 125. Gas circuit inside the mold 126. Gas circuit inside the mold 127. Gas circuit inside the mold 128. Kapla 129. Groove 130. Gas vent 131. Gas vent 132. Hole 133. Hole 134. Groove 135. An arrow indicating, for example, that compressed gas from a compressor is being introduced into a GCP (Gas Control Panel) device. 136. Arrows indicating the flow of compressed air 137. Arrows indicating the flow of compressed air into the mold. 138. Piping, circuits, hoses, etc. 139. Arrows indicating the flow of compressed gas inside the mold being exhausted into the atmosphere. 140. Arrow indicating the flow of compressed gas from inside the mold being drawn into the tank (part number 142) 141. Valve 142. Vacuum (reduced pressure) tank 143. Arrow indicating the flow of gas drawn in by vacuum pump number 144. 144. Vacuum pump 145. Pressure gauge indicating the degree of vacuum (reduced pressure) inside the tank 146. Check valve 147. Check valve 148. Check valve 149. Porous sintered metal that allows for the entry and exit of compressed air. 150. A porous sintered metal with multiple layers, allowing for the entry and exit of compressed air. 151. Nesting that fixes code number 150 152. Fixed or movable mold plate into which inserts (not shown) that define the molding space are inserted. 153. This shows the gap in the insert 154, which is provided for the purpose of allowing compressed air to enter and exit. 154. Nesting that forms code number 153 155. Molding space in which resin is filled into the movable mold and the fixed mold. 156. Number 156 indicates the portion that does not expand when number 61 is moved backward. 157. Schematic diagram showing that the movable part is embedded within the molded part. 158. Cross-section of a V-ring 159. V-ring opening 160. Opening of the U-ring 161. Opening of the U-ring 162. Face of an O-ring with a circular cross-section 163. To ensure sufficient sealing by vacuuming, the V-seal indicates that the opening 164 is facing away from the molding space. 164. V-ring opening facing outwards (opposite direction from the molding space) 165. Opening of the U-ring facing outwards (opposite direction from the molding space) 166. To ensure sufficient sealing by vacuuming, the opening 164 of the U-seal is oriented in the opposite direction to the molded space. 167. Check valve 168. Check valve 169. Vacuumed (reduced pressure) tank 170. A pressure gauge capable of outputting a pressure signal to check the pressure inside item number 169. 171. Hose 172. One-touch coupler with vacuum evacuation capability 173. Valve (Turns ON / OFF by signal number 170. Vacuum compatible) 174. Valve (A vacuum-compatible valve that guides the compressed air inside the mold to tank 169 after mold backing and core backing.) 175. Arrow (→) indicating the flow of compressed air under vacuum. 176. Manifold 177. Vacuum pump

Claims

1. A mold in which an ejector pin or other ejector shaft is sealed using a load-type O-ring and / or an O-ring with a U-shaped groove, or an ejector box structure in which a sealing mold is used. The gas used in GCP that utilizes the foamed stripe pattern generated on the surface is either air, nitrogen gas, carbon dioxide, or a mixture of two or more of these gases. If the pressure of that gas is 0.6 MPa or higher, Using a sealing mold, the inside of the sealing mold is pressurized with the aforementioned gas at 0.6 MPa or higher. Fill with foamed resin, When foamed resin is filled into the molding space by 90% by volume or more, A method for manufacturing a foamed molded product, comprising the step of exhausting the gas from the GCP into the atmosphere.

2. A mold in which an ejector pin or other shaft to be pushed out is sealed using a load-type O-ring and / or an O-ring with a U-shaped groove, or a mold sealed with an ejector box structure, The gas used in GCP to eliminate the foaming stripes that form on the surface is either air, nitrogen gas, carbon dioxide gas, or a mixture of two or more of these gases. If the pressure of that gas is 0.6 MPa or higher, The point at which the molding space is filled with foamed resin to the same volume as or greater than the molding space is considered the zero start, and the elapsed time from the zero start is arbitrarily delayed between 0 and 10 seconds, and when the arbitrarily set delay time is reached, A method for manufacturing a foamed molded product, comprising the step of exhausting the gas from the GCP into the atmosphere.

3. The mold, the GCP equipment, and the L of the mold １ , L ２ , L ３ Simultaneously with the start of exhausting part or all of the compressed air from the space such as the sub-tank of the GCP device no. 55, A method for manufacturing a foamed molded product, comprising a step of retracting the mold clamping mechanism of a molding machine and / or performing a mold-back and / or core-back of the movable mold to increase the foaming ratio.

4. A method for manufacturing a foamed molded product, comprising the step of increasing the foaming ratio by molding back and / or core-backing a fixed-side mold, rather than a movable-side mold, as described in claim 3.

5. A method for manufacturing a foamed molded product, comprising the steps of increasing the foaming ratio by molding back and / or core-backing both the movable side and the fixed side of the mold, according to claims 3 and 4.

6. In claims 3 to 5, simultaneously with the start of mold-back and / or core-back, L １ , L ２ , L ３ A method for manufacturing foamed molded products, which involves vacuuming a space such as a sub-tank designated as part number 55.

7. In any one of claims 3 to 5, a delay time of 0 seconds to 10 seconds from the start of mold back or / and core back is set, and L １ , L ２ , L ３ , a space such as the subtank denoted by reference numeral 55 is evacuated, which is a method for producing a foam-molded article.

8. In claims 1 and 2, L １ , L ２ , L ３ Simultaneously with the start of exhaust of compressed air from the space such as the sub-tank designated as part number 55, L １ , L ２ , L ３ A method for manufacturing foamed molded products, which involves vacuuming a space such as a sub-tank designated as part number 55.

9. In claims 1 and 2, L １ , L ２ , L ３ After a delay of 0 to 10 seconds from the start of exhausting the compressed air from the space such as the sub-tank designated as part number 55, L １ , L ２ , L ３ A method for manufacturing foamed molded products, which involves vacuuming a space such as a sub-tank designated as part number 55.

10. The control of the molding equipment used for foam molding is controlled by the PLC inside the molding machine. Using a GCP device, control of pressurized air and exhaust into the sealing mold, Injecting a gaseous and / or liquid foaming agent into the heating cylinder, and then stopping the process, Hollow molding involves injecting high-pressure gas into the resin filling the molding space to form a hollow inside, and Unlike pressure molding, which involves introducing high-pressure gas into the gap between the resin filled in the molding space and the mold, and using the pressure of the gas to pressurize the molten resin, A molding machine in which a program is incorporated into the PLC of the molding machine, and the control of the devices used for molding is performed by the PLC of the molding machine.

11. The GCP described in claim 10 is Once the molding machine confirms that the mold is closed, it opens the valve of the GCP device, L １ , L ２ , L ３ , pressurize the sealing space of the sub-tank, etc., designated as part number 55. When the process of pressurizing the space reaches a predetermined time, or / or when the pressure in the space reaches a predetermined pressure, the filling of the foamed resin into the molding space is started. A molding machine with a built-in program.

12. The molding space is filled with foamed resin, and during the filling process, or / or after the filling is completed, the valve of the GCP device is opened, L １ , L ２ , L ３ A molding machine with a built-in program that exhausts the compressed air from sealing spaces such as the sub-tank designated as part number 55 into the atmosphere.

13. L １ , L ２ , L ３ Simultaneously with the start of exhausting the pressurized air from the seal space of the sub-tank, etc., of reference number 55 into the atmosphere, or / or after a predetermined time has elapsed, the mold-back and / or core-back are initiated. A molding machine with a built-in program.

14. Simultaneously with the start of mold backing and / or core backing, or / or after a predetermined time has elapsed, A molding machine with a built-in program.

15. A molding machine for performing foam molding, equipped with a screw in which the L / D ratio of the plasticizing screw inside the heating cylinder of the injection molding machine used for foam molding is 15 or more, and the length of the compression section is 25% or more of the length of the screw.

16. In the plasticization melt kneading (plasticization metering) process, in which a foaming gas is pressurized and dissolved into the molten resin inside the heating cylinder, and then finely dispersed to impart foaming properties, a back pressure of 5 MPa or more is applied to the molten resin inside the heating cylinder. A molding machine that incorporates a program into the PLC to control the plasticization process of foamed resin.

17. The molding machine used for foam molding incorporates a program that initiates suck-back 0 to 10 seconds after filling with foam resin, in order to reduce the pressure of the resin filled in the molding space.

18. The molding machine used for foam molding incorporates a program that starts bleeding 0 to 10 seconds after filling with foam resin, in order to reduce the pressure of the resin filled in the molding space.

19. In the manufacturing of foam molding according to any one of claims 1 to 19, As a means of raising the temperature of the mold, Using a polyhydric alcohol as the heat transfer medium, A magnetic material is placed inside the thermal material, and the magnetic material is subjected to electromagnetic induction. A means of heating and directly heating the heat transfer medium, The heating device used for the mold.

20. The foaming agents ADCA, HDCA, and bicarbonate powders are used. Using a varnish made from resin that is compatible (solubilable) with the resin to be foamed, The foaming agent powder is supported on the surface of the resin pellets to be foamed, or on the surface of resin pellets that are compatible (soluble) with the resin to be foamed. A masterbatch of foaming agent used in foam molding.

21. In claim 3, if the resin to be foamed is AS, ABS, or a molding resin mainly composed of these, Using a varnish obtained by dissolving the aforementioned AS and ABS with an organic solvent, the foaming agent powder was supported on the surface of the resin pellets intended for foam molding. A masterbatch of foaming agent used in foam molding.

22. In claim 20, if the resin to be foamed is AS, ABS, or a molding resin mainly composed of these, The aforementioned AS and ABS are dissolved using an organic solvent, and the resulting varnish is further used as an emulsion or suspension system. The foaming agent is also used as a powder on the surface of the resin pellets to be foamed, or on the surface of resin pellets that are compatible (soluble) with the resin to be foamed, or supported on the surface. A masterbatch of foaming agent used in foam molding.

23. In claim 20, if the molding resin is PS, HIPS, modified PPO(E), or a molding resin mainly composed of these, Using a varnish obtained by dissolving the aforementioned PS and HIPS with an organic solvent, the foaming agent powder was supported on the surface of the resin pellets intended for foam molding. A masterbatch of foaming agent used in foam molding.

24. In claim 20, if the resin to be foamed is a molding resin mainly composed of PS, HIPS, and modified PPO(E), A masterbatch of a foaming agent used for foam molding, in which the aforementioned PS and HIPS are dissolved in an organic solvent to form a varnish, which is then used as an emulsion or suspension system, and the foaming agent powder is supported on the surface of resin pellets intended for foam molding.

25. In any of claims 20 to 24, The main components of the varnish used are AS, ABS, PS, HIPS, and modified PPO(E). A masterbatch of a foaming agent used for foam molding, wherein the foaming agent powder is supported on the surface of resin pellets intended for foam molding, or on the surface of resin pellets that are compatible with the resin intended for foam molding, using a varnish of an acrylic resin or styrene-modified acrylic resin that exhibits compatibility (solubility).

26. The varnish of claim 25 is an emulsion-type or suspension-type, and is manufactured using the same. A masterbatch of foaming agent used in foam molding.

27. In claim 20, if the resin to be foamed is PP or a molding resin mainly composed of PP, A masterbatch of a foaming agent used for foam molding, comprising acid-modified PP varnish, which is made soluble in an organic solvent by acid-modifying PP, and a foaming agent powder supported on the surface of PP pellets intended for foam molding, or on the surface of resin pellets that are compatible (soluble) with PP.

28. The varnish of claim 27 is an emulsion-type or suspension-type, and is manufactured using the same. A masterbatch of foaming agent used in foam molding.

29. A foaming agent masterbatch is produced by mixing only foaming agent powder and varnish, evaporating and drying the mixture, and then granulating and solidifying it. The masterbatch consists only of foaming agent and varnish resin and is used for foam molding.

30. In the production of the foaming agent master batch according to claim 29, A master batch of a foaming agent, obtained by evaporating and drying a foaming agent powder, a varnish, a powder of a resin intended for foam molding, or / or a powder of a resin compatible (solubilable) with the resin intended for foam molding, solidifying it, and granulating it.

31. Masterbatches of foaming agents used in foam molding are manufactured by separately supporting or granulating foaming agents, foaming aids, foam nucleating agents, and pigments / dyes. In each master batch, A method for manufacturing foamed molded products, in which each master batch is mixed and used before molding.

32. Using GCP, the surface of the foamed molded product is free from swirl marks that occur on the surface. Apply a coating, The quality of the adhesion and bonding of the surface coating was judged by a salt spray test based on JIS K5600-7-1. If blistering or peeling occurs in the coating, The foaming agents used in foam molding are selected from organic foaming agents such as ADCA and HDCA, and liquid foaming agents such as water, alcohols, ethers, and esters. A foamed molded product produced using GCP (Ground Pressure Plating).

33. When foam molding is performed using GCP, the foaming agent selected is at least a bicarbonate, a foaming agent containing the bicarbonate, or an aqueous solution containing the bicarbonate, and the foam molding surface used is Apply a coating, The quality of the adhesion and bonding of the surface coating was judged by a salt spray test based on JIS K5600-7-1. If blistering or peeling occurs in the coating, Before painting, the surface of the molded product is cleaned with an acidic aqueous solution, and then painted. A foamed molded product produced using GCP (Ground Pressure Plating).

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