Foaming molding device and foaming molding method

Abstract

The present invention relates to a foaming molding device and a foaming molding method using the device, wherein the foaming molding device preferably comprises: a foaming agent supplying section for injecting a foaming agent; a molten resin supplying section for injecting a molten resin; a fixed type mixing section for mixing the foaming agent injected from the foaming agent supplying section and the molten resin injected from the molten resin supplying section together from an internal rod-shaped body to form a foaming resin critical solution; and a molding section for molding a foamed molded product using the foaming resin critical solution injected from the fixed type mixing section. By using a high-strength multi-channel flow channel, a high-viscosity gel-like molten resin and a high-pressure compressed low-viscosity foaming agent are uniformly mixed in large quantities to form a foaming resin critical solution, so that the number of foaming pores generated from the molding section or the injection mold when injecting or injecting the foaming resin critical solution can be greatly increased, thereby greatly reducing the specific gravity of the foamed molded product and achieving lightweight foamed molded products.

Description

Technical Field

[0001] The present invention relates to a foaming molding device and a foaming molding method thereof, and more specifically, to a foaming molding device and a foaming molding method thereof, which manufacture ultra-low specific gravity foamed molded products by molding, and the surface of the ultra-low specific gravity foamed molded products will not foam, thereby manufacturing ultra-light and high-strength foamed molded products. Background Art

[0002] The molding of synthetic resin or metal mainly refers to injecting molten synthetic resin or metal between a fixed mold (cavity mold) forming a cavity and a movable mold (core mold) forming a core and cooling it to obtain a molded product in the shape of the cavity. This molding mainly involves injecting molten resin into a mold of a certain shape and compressing it at high temperature and high pressure to produce products. In most cases, it is used for the molding of thermoplastic resins.

[0003] In contrast, in the molding of a shape in which the fixed mold is not enclosed by the movable model, that is, profile molding, it is like 3D printing, and the nozzle for injecting molten resin moves toward the fixed model, or conversely, the mold moves toward the fixed nozzle to inject molten resin into the mold to obtain a molded product, thereby greatly reducing mold costs and allowing the production of very large objects through molding.

[0004] On the other hand, in order to produce products with reduced weight but the same shape, attempts have been made to produce foamed molded products using chemical foaming agents or carbon dioxide and nitrogen. However, the foaming ratio is, for example, as shown in the injection molding mold device and foamed resin product manufacturing method disclosed in Patent Publication No. 10-2012-0029599, the resin and the foaming agent are stirred and mixed by rotating wings, so the position or number of the foaming agent injection port is limited. Since the injection of the foaming agent to the molten resin is limited, the maximum can only be about 1.5 times, and the specific gravity of the molded product is also at least 0.7. Therefore, the desired low-specific-gravity foamed molded product cannot be produced with current technology. Moreover, the skin of the foamed molded product is as follows. Figure 1 The surface is rough, the strength and appearance are reduced, and surface treatment such as coating is required before it can be used in practice.

[0005] In other words, when manufacturing foam molded products, in order to increase the foaming ratio, the high-pressure compressed liquid foaming agent should be evenly mixed in the molten resin and the content of the foaming agent should be increased. However, it is very difficult to mix the high-viscosity viscoelastic molten resin and the high-pressure liquefied foaming agent that is similar to gas and has extremely low viscosity in a shell heated at a high temperature of about 200°C or above under high pressure. The method used in the past was to use a spiral screw to mix the molten resin in the shell of the injection molding device, set a flow channel inside the screw to input the compressed liquid foaming agent, use the rotation of the screw to mix the molten resin and the liquid foaming agent, and then make the screw move forward by hydraulic or electric high pressure to fill the foamed resin mixture that flows into the front end of the screw into the cavity of the injection mold. Therefore, in a pressurized atmosphere, it is not only difficult to produce a completely uniform mixture by mixing molten resin and foaming agent in different states with very different viscosities by rotating a screw, but also it is necessary to maintain a sealed high pressure state in order to produce the molten resin produced by this method to prevent the molten resin from leaking out. Therefore, from the perspective of durability strength and sealing performance, it is impossible to add a sufficient amount of liquid foaming agent in a short flow distance interval, which not only causes the foaming ratio of the foamed molded product to be limited to an extremely low level, but also the foamed molded product produced by this method has most of the foaming pores exposed on the surface, and the foaming pores in the central part are formed in a sparse state, resulting in a very rough surface of the molded product, making it difficult to process the surface after processing, and causing the appearance to become rough, resulting in a problem that it cannot be used as an appearance product. Summary of the invention

[0006] Technical issues

[0007] The present invention is proposed to solve the problems existing in the conventional foam molding apparatus as described above. Its purpose is to maximize the content of a foaming agent in a high-pressure compressed state such as liquefied carbon dioxide or liquefied nitrogen and water or steam in a foamed product by mixing them in large quantities as much as possible before feeding them into a molding part such as a mold, so that when the foaming agent expands in a molding part such as a mold, the density of the foaming space can be increased, thereby reducing the specific gravity of the foamed product, for example, to 0.8 g / cm 2 the following.

[0008] Another object of the present invention is to apply a gas pressure of up to 200 in order to fully input the foaming gas, so that the foaming gas is evenly dispersed in the resin as microparticles, and the mixture of the molten resin and the foaming gas forms a complete critical solution, thereby reducing or completely eliminating the foaming phenomenon on the surface of the molded product, forming a high-strength smooth surface, and maximally limiting the improvement of the strength weakened by foaming, thereby manufacturing a high-strength and low-specific-gravity foamed molded product.

[0009] Technical Solution

[0010] To achieve the above-mentioned purpose, the present invention provides a foaming molding device, which comprises: a foaming agent supply section for inputting a foaming agent; a molten resin supply section for inputting a molten resin; a fixed mixing section for mixing the foaming agent inputted from the foaming agent supply section and the molten resin inputted from the molten resin supply section together through a multi-channel flow channel of an internal rod-shaped body to form a foaming resin critical solution; and a molding section for molding a foamed molded product using the foaming resin critical solution inputted from the fixed mixing section.

[0011] Preferably, the rod-shaped body includes: a plate-shaped body formed by arranging a plurality of unit cells forming pores in two dimensions; a spacer connected between the plate-shaped bodies so that the plate-shaped bodies are laminated and the unit cells are arranged in three dimensions; the spacer can connect adjacent plate-shaped bodies to maintain the spacing of the pores.

[0012] Preferably, the plate-like body is a layered structure in which the same pattern is formed two-dimensionally and repeatedly.

[0013] Preferably, the rod-shaped body is a laminated structure in which the layered structure and the spacer repeatedly form the same pattern as the repeated pattern of the layered structure in a direction of connection with the adjacent layered structure via the spacer.

[0014] Preferably, the rod-shaped body is formed by a laminated structure in which the unit cell and the spacer are repeatedly formed in the xyz axis direction with a circle as the center, the unit cell is a solid formed by overlapping three octagonal columns with a square as an outer peripheral surface and configuring each axis along the xyz axis with the circle as the center, and the spacer is a regular hexahedron that extends on the outer peripheral surface intersecting the axis and is connected to the outer peripheral surface of the adjacent unit cell and has the outer peripheral surface as one face.

[0015] Preferably, the rod-shaped body is a solid body having the same shape as the unit cell and the spacer.

[0016] Preferably, the foaming agent supply unit includes one or more locations for injecting the foaming agent into the fixed type mixing unit.

[0017] Preferably, the method further comprises: a foaming resin storage section for temporarily storing the foaming resin critical solution supplied from the stationary mixing section before being fed into the molding section.

[0018] Preferably, the method further comprises: a foaming resin injection unit for temporarily storing the foaming resin critical solution supplied from the fixed mixing unit before injecting it into the molding unit.

[0019] Preferably, the foamed resin injection unit includes a heating unit that heats the foamed resin critical solution and stores it in a molten state.

[0020] Preferably, the mold further comprises a foaming resin extruding section for temporarily storing the foaming resin critical solution supplied from the fixed mixing section to extrude the foaming resin critical solution to the molding section.

[0021] The present invention provides a foaming molding method, comprising: a molten resin supplying step of feeding molten resin from a molten resin supplying section into a fixed mixing section; a foaming agent supplying step of feeding foaming agent from a foaming agent supplying section into the fixed mixing section; a fixed mixing step of allowing the molten resin and the foaming agent respectively fed into the fixed mixing section to pass through the pores of the fixed mixing section together in the molten resin supplying step and the foaming agent supplying step, thereby dispersing and expanding the flow paths through which the molten resin and the foaming agent flow and mixing them into a foaming resin critical solution; and a foaming resin molding step of concentrating the foaming resin critical solution mixed and injected in the fixed mixing step into a foaming resin injection section and then injecting it into a molding section to be molded into a foamed molded product; the fixed mixing section comprises: a plate-like body formed by arranging a plurality of unit cells forming pores in two dimensions; a spacer connecting the plate-like bodies to laminate the plate-like bodies and thereby arranging the unit cells in three dimensions; the spacer can connect adjacent plate-like bodies to maintain the spacing of the pores.

[0022] Preferably, the foaming agent supplying step is that when the foaming agent is fed into the fixed mixing part at an odd foaming agent feeding part, the amount of foaming agent fed into the fixed mixing part from the foaming agent feeding part gradually increases with the passage of time, and the foaming resin molding step is that the closer the foaming agent content is to the injection port of the foaming resin injection part, the less or no foaming agent content is, and the farther away the foaming agent content is, the more foaming resin critical solution is filled into the foaming resin injection part, so that the foaming resin critical solution injected from the foaming resin injection part to the molding part gradually increases in foaming agent content with the passage of injection time, thereby gradually increasing the foaming ratio, and at the same time, the filling position of the molding part is moved from the skin of the foamed molded product to the center.

[0023] Beneficial Effects

[0024] According to the foam molding device and the foam molding method of the present invention, the beneficial effect is that a high-viscosity gel-like molten resin and a low-viscosity high-pressure compressed foaming agent are introduced into a high-pressure atmosphere of more than 200 atmospheres through a high-strength fixed mixing section with multiple flow channels, and a large amount of them are uniformly mixed to produce a foaming resin critical solution. Therefore, when the foaming resin critical solution is introduced or injected into a molding section or an injection mold, the number of foaming pores generated from the molding section or the injection mold can be greatly increased, thereby greatly reducing the specific gravity of the foamed molded product, thereby achieving lightweight foamed molded products.

[0025] Furthermore, as described above, when the mixture of the resin and the foaming gas that forms a complete critical solution under a high pressure atmosphere is molded, the foamed particles formed on the molded product are formed as ultra-fine particle bubbles with a diameter of less than 0.1 mm, i.e., micro units;

[0026] Therefore, a foamed product with a clean surface can be obtained;

[0027] Moreover, the molten resin supplied to the mixing section can maintain a completely molten state at any position of the fixed mixing section, so the foaming agent injection point can be set at any position of the fixed mixing section;

[0028] Furthermore, a plurality of foaming agent injection locations can be set, and each of the plurality of injection locations can adjust the amount of foaming agent injection by an on-off valve, so that the mixing ratio of the foaming agent and the molten resin in the fixed mixing section can be changed according to the position of the injection location;

[0029] Furthermore, when the foaming agent injection point is set to an odd number, the on-off valve can be adjusted so that the amount of foaming agent injected into the fixed mixing section changes over time;

[0030] The foaming agent content of the foamed resin critical solution injected from the fixed mixing part into the foamed resin injection part changes with the filling position in the foamed resin storage part or the injection part shell, thereby improving the appearance quality of the foamed molded product injected into or injected into the molding part or the injection mold and then foamed and molded as needed, and enhancing the strength of the foamed molded product weakened by foaming;

[0031] For example, the closer to the nozzle of the foaming resin storage part, the more the foaming agent content increases, and the farther from the nozzle, the less the foaming agent content, or it can be made 0 at the farthest position, so that the foaming resin critical solution with no or little foaming agent content is located at the rear end of the foaming resin storage part, and the foaming resin critical solution with a high foaming agent content initially input is filled into the molding part to form the inside of the molded product, and the foaming resin critical solution with no or little foaming agent content is filled to form the skin of the molded product, and then the skin of the foamed molded product forms an unfoamed resin layer, and the closer to the center, the more a foaming layer with a high foaming ratio is formed;

[0032] For example, the closer to the injection port of the foamed resin injection part, the less the foaming agent content, or it is 0 at the closest position, and the farther from the injection port, the more the foaming agent content increases, so that the foamed resin critical solution with no or little foaming agent content is located at the front end of the foamed resin injection part, and the further back, the more the foaming agent content increases. Then, during the injection, the foamed resin critical solution with no or little foaming agent content injected at the initial stage is filled along the inner circumference of the cavity as the skin of the foamed molded product like smearing, and the foamed resin critical solution with gradually increasing foaming agent content is filled to the inside of the skin, and finally fills the center part, so that the skin of the foamed molded product forms an unfoamed resin layer, and the closer to the center, the foamed layer with a higher foaming ratio is formed;

[0033] The center part is formed with a high-ratio foam layer to achieve lightness, and the surface part is formed with an unfoamed resin layer to increase strength. As a whole, a structural foamed molded product with a spiral nest structure, high strength and lightness is obtained;

[0034] The surface of the foamed product is formed with an unfoamed resin layer, which can further improve the appearance of the foamed product;

[0035] During injection molding, the skin of the foamed molded product that contacts the inner surface of the cavity is formed by the unfoamed resin layer and has the highest density in the entire foamed molded product. It also greatly reduces the shrinkage rate that occurs when the foamed resin critical solution solidifies. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is an example diagram of a foamed product that is foam-molded by mixing a foaming agent in a molten resin using an existing stirring mixing method;

[0037] Figure 2 is a schematic diagram briefly illustrating a foaming molding device according to an embodiment of the present invention;

[0038] Figure 3 It is a graphic form Figure 2 A perspective view of a rod-shaped body of a fixed mixing section shown in FIG.

[0039] Figure 4 It is shown in the end view Figure 3 The plan view of the rod-shaped body;

[0040] Figure 5 It is a perspective view that magnifies the internal shape of the rod-shaped body;

[0041] Figure 6 Yes Figure 3 A perspective view of the unit cell forming the rod-like body in a simplified linear diagram;

[0042] Figure 7 Yes Figure 6 A perspective view of the unit cell separated by morphological element categories;

[0043] Figure 8 is a perspective view schematically illustrating a unit cell of another embodiment;

[0044] Fig. 9 is a schematic diagram briefly illustrating a foaming molding device according to another embodiment of the present invention;

[0045] Fig.10 This is an exemplary diagram of a foam-molded product obtained by mixing and foaming a molten resin and a foaming agent using the foam-molding apparatus of the present invention.

[0046] Best Mode for Carrying Out the Invention

[0047] The foaming molding device according to one embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] The foaming molding device of the present invention is as follows Figure 2 The molded product is shown simply in FIG. 1 , and generally includes a foaming agent supply section 3 , a molten resin supply section 5 , a fixed mixing section 7 and a molding section 8 .

[0049] Here, the foaming agent supplying section 3 is a means for feeding and supplying the foaming agent for mixing the foaming resin critical solution to the fixed type mixing section 7, for example, Figure 2 As shown, at least one of the first to third pipes 15, 16, 17 is connected to the fixed mixing section 7, and one or more foaming agent input parts 25, 26, 27 of the fixed mixing section 7 are provided. Therefore, the foaming agent supply part 3 is, for example, to supply foaming agents such as liquid carbon dioxide, liquid nitrogen, high-pressure hydrogen, steam, ethanol, organic polymer gas, helium, etc. to the fixed mixing section 7 simultaneously or at intervals through the input parts 25, 26, 27. Further, as the foaming agent, it is preferable to use a high-pressure compressed liquefied foaming agent such as liquid carbon dioxide and liquid nitrogen, which has a relatively low viscosity due to its properties.

[0050] The molten resin supplying section 5 is a means for feeding and supplying the molten resin for mixing the foaming resin critical solution with the foaming agent to the fixed type mixing section 7. Figure 2 As shown, it is connected to one end of the fixed mixing section 7. At this time, the molten resin supply section 5 is also Figure 2 Only one is shown in the figure, but multiple ones can be set according to needs.

[0051] On the other hand, the molten resin supply unit 5 can be made not only in the form of a container for receiving and supplying the resin after it is melted externally, but also in the form of a container for receiving and supplying the resin externally. Figure 2 The melting device shown is made to melt the resin directly from the outside. Figure 2The molten resin supply section 5 shown in the figure is composed of a cylindrical shell 51 for melting the input resin, a conveying screw 53 and a screw driving motor 55. The resin input from the outside into the shell 51 is heated and melted by a heating device (not shown), and the driving motor 55 is operated to be conveyed to the discharge port 52 through the conveying screw 53. Then, the molten resin melted in the molten resin supply section 5 is conveyed in a relatively high viscosity gel state (actually a viscoelastic state) and input into the fixed type mixing section 7. However, the conveying screw 53 may be operated hydraulically.

[0052] The fixed type mixing section 7 is a device for mixing the foaming agent fed from the foaming agent supply section 3 and the molten resin fed from the molten resin supply section 5. Figures 2 to 4 As shown, a rod-shaped body 70 is provided inside to form a multi-channel flow channel P, and Figure 2 Only the internal rod-shaped body 70 is shown in the figure, but of course there is also an external shell surrounding the rod-shaped body 70 or the first to third pipes 15, 16, 17 or a connecting pipe connected to the discharge outlet of the molten resin supply part 5, etc., but for convenience, they are omitted from the figure.

[0053] As described above, the fixed type mixing section 7 can evenly mix the high viscosity gel-like molten resin supplied by the molten resin supply section 5 and the low viscosity high pressure compressed liquid foaming agent supplied by the foaming agent supply section 3, but does not adopt the conventional rotary stirring method of rotating the stirring device to mix the mixing objects, but adopts the fixed type stirring method of repeatedly dispersing, expanding and mixing the mixing objects in the flow channel when the fluids of the mixing objects flow together, so as to mix the molten resin of the foaming agent. For this purpose, the fixed type mixing section 7 is as follows Figures 3 to 5 As shown in FIG. 1 , the rod-shaped body 70 is formed with a porous structure. Further, the rod-shaped body 70 of the fixed mixing section 7 is as follows Figures 3 to 5 As shown, it is formed as a porous matrix having a plurality of pores.

[0054] For this purpose, the rod-shaped body 70 is as follows Figures 3 to 5 As shown, it includes a plurality of plate-like bodies 71 and a plurality of spacers 73 connecting these.

[0055] Here, first, the plate-like body 71 is the smallest unit of the pore, that is, the unit cell 80 is a two-dimensional image. Further, in the xyz coordinate system with a circle as the center, a plurality of plate-like bodies 71 are arranged along the xy plane, the yz plane or the zx plane. The shapes of the plate-like bodies 71 may be the same or different, and the shapes of the unit cells 80 in a plate-like body 71 may be the same or different, and the plate-like bodies 71 may be repeatedly arranged regularly or irregularly. Figures 3 to 8As shown, preferably, a two-dimensional uniform pattern is formed repeatedly, that is, a layered structure is formed, and the unit cell 80 is as small as possible to be able to stir the foaming agent and the molten resin by the above-mentioned fixed stirring method.

[0056] The spacer 73 is used to connect the plate-like body 71 and the adjacent plate-like body 71, and to ensure the spacing between the plate-like body 71 and the plate-like body 71. In order to laminate the plate-like body 71 and the plate-like body 71 to form the rod-like body 70, the single cells 80 arranged in two dimensions in the plate-like body 71 are arranged in three dimensions by laminating the plate-like body 71. Further, a plurality of them are arranged in the space formed by the xyz axis. Moreover, the spacer 73 can make the space between the plate-like body 71 and the plate-like body remain, and then when the high-pressure foaming agent is put into the rod-like body 70 with high viscosity molten resin having viscoelasticity, even if the molten resin is pressurized by the foaming agent, the plate-like body 71 and the plate-like body can still pass through unimpeded. That is, the spacer 73 is used to connect the plate-like body 71 and the plate-like body 71, and to ensure that the pore spacing can be maintained between the connected plate-like body 71 and the plate-like body 71.

[0057] However, when the spacer 73 is a plate-like body 71 formed into a layered structure as described above, that is, the structure of the internal pores is a two-dimensional image, and the same pattern is repeated, for example, Figures 3 to 5 In the enlarged diagram, the rod-shaped body 70 formed by the same pattern as the internal repetitive pattern of the layered structure is repeated in the connection direction of the two layered structures adjacent to the connected layered structure, and is called a laminated structure. Therefore, the laminated structure is, for example, Figures 3 to 5 As shown in the enlarged diagram, the same pattern can be repeated in a three-dimensional image. That is, the laminated structure has a three-dimensional lattice structure.

[0058] at this time, Figures 3 to 5 The minimum pattern forming the laminated structure shown in FIG. Figure 6 and Figure 7 As shown in the figure, it is formed by a unit cell 80 and a spacer 73 connected to one side thereof. Further, Figures 3 to 5 The rod-shaped body 70 shown in the figure is a laminated structure formed by repeating a basic pattern formed by one unit cell 80 and one spacer 73 in the xyz axis direction with one dot as the center.

[0059] Figure 6 The basic pattern shown in the figure is as follows Figure 7 As shown in the figure, it can be separated and illustrated according to the type of morphological elements. Accordingly, the unit cell 80 is a solid formed by overlapping three octagonal columns Ox, Oy, and Oz with a square as an outer peripheral surface F so that each axis is arranged along the xyz axis with a circle as the center. When the spacer 73 is arranged on the zy plane as a plate-like body 71, that is, a layered structure, as shown in FIG. Figure 6 As shown in the figure, the spacer 73 is formed by extending on the outer peripheral surface F where the axis is arranged along the x-axis, that is, the outer peripheral surface F intersecting the axis, and then connected to the outer peripheral surface F corresponding to the unit cell 80 of the plate-like body 71 adjacent to the outer peripheral surface F. At this time, the octagonal columns Ox, Oy, and Oz are all regular octagons, so the spacer 73 becomes a regular hexahedron with the outer peripheral surface F as one face.

[0060] on the other hand, Figure 8 The figure shows another embodiment of the unit cell 180. The unit cell 180 is also the smallest unit for forming the rod-shaped pores. A plurality of the unit cells 180 are arranged in a two-dimensional image to form a plate-like body, but each plate-like body has the same shape. In addition, the unit cells 180 of the same shape are regularly and repeatedly arranged in a plate-like body to form a layered structure. In this case, the unit cell 180 is not larger than the size that can stir the foaming agent and the molten resin by a fixed stirring method.

[0061] Furthermore, the rod-shaped body formed by the unit cells 180 is a spacer between the adjacent unit cells 180, so the same pattern can be repeated not only in two dimensions but also in three dimensions. That is, the rod-shaped body is equivalent to a plate-shaped body formed by the unit cells 180 of the first and third rows, and the unit cells 180 of the second row are used as spacers to form a laminated structure.

[0062] Therefore, the fixed mixing section 7 is to mix the foaming agent and the molten resin together through the multi-channel flow path P under high temperature and high pressure atmosphere, and then make a foamed resin critical solution. This is because when the foaming agent and the molten resin flow in the multi-channel flow path P of the fixed mixing section 7, they are repeatedly dispersed and gathered according to the size of the flow path P, so as to be uniformly mixed. At this time, the fixed mixing section 7 is formed with a high-strength rod-shaped body 70, so there is no need to worry about the durable strength, and high-viscosity fluid can pass through. Since there is no need to worry about the durable strength, the diameter of the multi-channel flow path P, that is, the pore size, does not need to be too large, and the mixing state will not be poor due to the increase in the diameter of the multi-channel flow path P, so there is no need to extend the length of the rod-shaped body 70 for mixing uniformity.

[0063] As described above, the solution state in which the blowing agent and the molten resin are uniformly mixed under high temperature and high pressure atmosphere is defined as the foaming resin critical solution, which may also be called the foaming molten resin critical solution because a pseudo solution or critical solution state is formed.

[0064] Although the fixed mixing section 7 of the foam molding apparatus 1 is not shown in the figure, the mixed foaming resin critical solution may be directly fed into the molding section 8 without passing through the foaming resin storage section 11 .

[0065] But if Figure 2As shown in the figure, it is preferred to have a foaming resin storage section 11. The foaming resin storage section 11 is a means for storing the foaming resin critical solution for molding, and is connected to the injection port 89 side of the fixed type mixing section 7. As described above, the foaming resin critical solution squeezed out through the injection port 89 by pressure after mixing in the fixed type mixing section 7 is temporarily stored here. To this end, the foaming resin storage section 11 includes a shell 81 forming a main body, a nozzle on the shell 81 on the opposite side of the injection port 89, and a valve 85 for opening and closing the nozzle. It can also include a heating section 87 to heat the foaming resin critical solution put into the shell 81 and store it in a molten state.

[0066] The foaming resin storage section 11 maintains the foaming resin critical solution injected into the shell 81 from the fixed mixing section 7 in a molten state through the heating section 87 as needed, and when a certain amount is measured in the shell 81, the valve 85 is opened and injected into the molding section 8 through the nozzle 83.

[0067] The forming part 8 is as follows Figure 2 As shown, the part of the predetermined foamed molded product formed by the foamed resin critical solution introduced from the foamed resin storage unit 11 can be provided in various forms according to the molding method, and according to Fig. 9 As described later, the injection mold 9 is used when the foaming resin critical solution is injection molded, and the extrusion mold is used when extruding or profile extruding. Figure 2 As shown, during profile forming, the forming portion 8 is formed by a forming plate that can move forward, backward, left, right, and up and down. However, when the forming portion 8 is fixed, the nozzle 83 and the housing 81 are connected by a flexible tube or the like, so that the nozzle 83 can move forward, backward, left, right, and up and down of the forming portion 8. As described above, when performing profile forming, the mold cost can be greatly reduced, and it is also possible to form an extra-large object.

[0068] The foaming molding device according to another embodiment of the present invention is Fig. 9 The foam molding device 101 is shown in the figure and is similar to the foam molding device 1. The foam molding device 101 is generally composed of a foaming agent supply unit 3, a molten resin supply unit 5, a fixed type mixing unit 7 and a molding unit 9. The foam molding device 101 is similar to the foam molding device 1 except that the foaming resin storage unit 11 of the foam molding device 1 is replaced by a foaming resin injection unit 13 and an injection mold is used as the molding unit 9.

[0069] Therefore, the description of the foaming agent supply unit 3, the molten resin supply unit 5, and the fixed type mixing unit 7 is replaced by the description of the above-mentioned foam molding device and is omitted here.

[0070] However, the foaming resin injection unit 13 is a unit that temporarily stores the foaming resin critical solution mixed and injected in the fixed mixing unit 7 for injection. Fig. 9As shown, it is connected to the injection port 89 side of the fixed mixing section 7, and includes a shell 91 forming a main body, a plunger or screw 93 assembled in the shell 91, a driving motor 95 that drives the plunger 93 through a push rod 94, and a heating section 97 for heating the critical solution of the foaming resin put into the shell 91 into a molten state for storage.

[0071] The foaming resin injection section 13 injects the foaming resin critical solution into the shell 91 from the fixed mixing section 7, and when a certain amount is measured in the shell 91, it is injected into the molding section 9 in the form of an injection mold connected to the outlet side by driving the motor 95 or hydraulically moving the plunger or screw 93 back and forth.

[0072] The forming part 9 is as follows Fig. 9 As shown, the foaming resin critical solution injected from the foaming resin injection unit 13 is filled into the cavity and molded into a predetermined foamed molded product.

[0073] The following describes a foaming method using the foaming device 1, 101 according to a preferred embodiment of the present invention.

[0074] The foaming molding method of the present invention generally includes a molten resin supplying step S10, a foaming agent supplying step S20, a fixing and mixing step S30, and a foaming resin molding step S40.

[0075] Here, the molten resin supplying step S10 is a step of feeding the molten resin of the molten resin supplying part 5 into the fixed type mixing part 7. Figure 2 As shown, the molten resin initially fed into the molten resin supply section 5 in a molten state or the high-viscosity molten resin melted in the molten resin supply section 5 after being fed in a pre-molten state is fed into the fixed mixing section 7 through the discharge port at the front end by the rotation of the conveying screw 53 operated by a motor 55 or hydraulically.

[0076] The foaming agent supplying step S20 is a step of feeding the foaming agent from the foaming agent supplying unit 3 into the fixed type mixing unit 7. Figure 2 As shown, the foaming agent compressed under high pressure in the foaming agent supply unit 3 is fed into the fixed type mixing unit through one or more pipes 15, 16, and 17.

[0077] The fixed mixing step S30 is a step of mixing the molten resin and the foaming agent respectively introduced into the fixed mixing part 7 as described above in the molten resin supplying step S10 and the foaming agent supplying step S20. Figure 2As shown, molten resin and foaming agent are passed through the multi-channel flow path P of the fixed mixing section 7 together, and when molten resin and foaming agent pass through the multi-channel flow path P, they are repeatedly dispersed and assembled, and then uniformly mixed into the foamed resin critical solution. At this time, the rod-shaped body 70 of the fixed mixing section 7 is formed with high-strength metals such as titanium or plastics, so the caliber of the multi-channel flow path P, i.e., the size of the pore, can be freely adjusted. And the caliber of the multi-channel flow path P, i.e., the internal space density, can be adjusted as mentioned above, so a large amount of foaming gas can be dropped in simultaneously or successively. And different from the existing foamed resin mixer that can not seal the running part of the screw rotation with more than 120 gas pressures, the multi-channel flow path P as mentioned above is also easy to seal with more than 200 gas pressures, so even if a large amount of foaming gas is dropped with high pressure, it can still be sealed.

[0078] The foaming resin molding step S40 is a step of injecting the foaming resin critical solution mixed and injected by the fixed mixing part 7 in the fixed mixing step S30 into the molding part 8 to mold a foamed molded product. Figure 2 As shown, the foamed resin critical solution injected into the foamed resin storage portion 1 is first collected in the foamed resin storage portion 11 and then introduced into the molding portion 8 when the valve 85 is opened.

[0079] At this time, the foaming resin critical solution injected from the fixed type mixing unit 7 into the foaming resin storage unit 11 is filled into the cylindrical shell 81 in a direction from a portion farther from the injection port 89 connected to the fixed type mixing unit 7 to a direction gradually approaching. Figure 2 As shown, when the injection port 89 is arranged at the front end of the shell 81, the foamed resin critical solution injected from the fixed mixing unit 7 into the foamed resin storage unit 11 is filled while gradually approaching the top from the bottom of the shell 81 far from the injection port 89.

[0080] Then, the foaming resin critical solution filled in the housing 81 is injected into the molding part 8 through the nozzle 83 when the valve 85 is opened, and then molded into a foamed molded product. At this time, for example, when the profile is molded, the foaming resin critical solution is injected while the molding part 8 moves, and then the molding part 8 is filled. Therefore, the movement of the molding part 8 is controlled by a computer, etc., just like 3D printing for molding.

[0081] On the other hand, the present invention adopts the fixed type mixing part 7 as a means for mixing the foaming agent and the molten resin. The foaming agent can be added to any part of the surface of the rod-shaped body 70 under the same conditions. That is, the molten resin added to the multi-channel flow path P is in a completely molten state at any part of the multi-channel flow path (P). When the molten resin is added to the multi-channel flow path P, the influence of the foaming agent on the foaming agent remains at a constant level. Figure 2 As shown, the injection point for injecting the foaming agent into the fixed type mixing section 7 can be set at any position, and more than one position can be provided.

[0082] As described above, the plurality of pipes for feeding the foaming agent, namely the first to third pipes 15, 16, 17, can all be controlled to open and close by the on-off valve 21. Therefore, the foaming agent supply unit 3 can change the amount of foaming agent fed to the fixed type mixing unit 7 according to the foaming agent feeding position by adjusting the selective opening degree of the on-off valve 21. Furthermore, the foaming agent supply unit 3 controls the amount of foaming agent fed to each foaming agent feeding position over time by adjusting the opening and closing time of the on-off valve 21.

[0083] When there are multiple foaming agent feeding locations for feeding the foaming agent into the fixed type mixing unit 7, the opening degrees of the valves 21 of the first to third pipes 15, 16, 17 are adjusted in the foaming agent supply step S20, and the positions of the feeding locations are closer to the injection port 89 of the fixed type mixing unit 7, that is, for example, Figure 2 Compared with the second and third pipelines 16 and 17, the amount of foaming agent added can be reduced or the foaming agent addition can be stopped at the injection point of the first pipeline 15.

[0084] Further, the fixed mixing section 7 is composed of various pipelines 15, 16, 17 such as Figure 2 As shown, the distances from each input portion 25, 26, 27 to the injection port 89 are different. Therefore, even if the foaming agent is simultaneously input into each pipeline 15, 16, 17, there will be a time difference in the input time of the foaming resin critical solution input into the molding part 8 through the injection port 89 and the nozzle 83 due to the difference in the distance from each input port to the injection port 89. By adjusting the opening degree of each valve 21, the amount of foaming agent input from the foaming agent input port can be changed over time. For example, through pipeline 15, the valve 21 is opened to the minimum, so that the amount of foaming agent input into the fixed type mixing part 7 becomes the minimum. Through pipeline 16, the amount of foaming agent input can be made to reach an intermediate level. Through pipeline 17, the valve 21 can be opened to the maximum, thereby maximizing the amount of foaming agent input.

[0085] Subsequently, the largest amount of foaming agent introduced through the pipe 17 closest to the injection port 89 produces a high-ratio, i.e., a foamed resin critical solution with the largest bubbles, and the high-ratio critical solution is first introduced into the molding portion 8 through the nozzle 83. Moreover, the intermediate-ratio critical solution formed by the intermediate amount of foaming agent introduced through the pipe 16 at an intermediate distance is introduced into the molding portion 8 after the high-ratio critical solution, and the low-ratio critical solution formed by the small amount of foaming agent introduced through the farthest pipe 15 is introduced into the molding portion 8 last. Subsequently, a high-ratio, i.e., lowest-density foaming portion is formed inside the molded product, and a low-ratio, i.e., highest-density foaming portion is formed on the surface. Finally, a high-ratio foaming layer is formed in the center portion to reduce weight, and a low-ratio or unfoamed resin layer is formed in the surface portion to increase strength, so that a structural foamed molded product having a honeycomb structure, high strength, and reduced weight can be obtained as a whole.

[0086] When the number of foaming agent injection positions is odd, the opening degree of the valve 21 may be gradually reduced over time in the foaming agent supply step S20, so that the amount of foaming agent injected into the fixed mixing section 7 is gradually reduced to 0 over time. Furthermore, in the foaming resin molding step S40, the foaming resin critical solution injected into the position adjacent to the injection port 89 of the shell 81, that is, injected and filled into the shell 81 later, has no foaming agent content or becomes less, and the farther from the injection port 89, the more the foaming agent content increases.

[0087] Similarly, the foaming resin critical solution injected into the molding part 8 from the foaming resin storage part 11 has a foaming agent content that gradually decreases and a rate that gradually decreases as the injection time passes. Therefore, the foaming agent content of the foaming resin critical solution is filled in the molding part 8 at the maximum state at the initial injection time, and then the inside of the foamed molded product is formed. As time passes, the foaming agent content gradually decreases, and the filling position gradually moves to the surface of the foamed molded product. In other words, the foaming agent content of the foaming resin critical solution injected into the molding part 8 from the foaming resin storage part 11 is, for example, the maximum at the beginning but gradually decreases as time passes. Therefore, a foaming resin critical solution with a large foaming agent content is formed inside the foamed molded product, and a high-rate foaming occurs. On the contrary, a resin layer without a foaming agent or less foaming agent is formed on the surface of the foamed molded product, and then the high-rate foaming part located inside is surrounded. As a result, the surface of the foamed molded product also becomes an unfoamed resin layer, and a high-rate foamed resin layer is formed in the center, and a honeycomb structure is formed as a whole, thereby forming a high-strength structural foamed molded product.

[0088] The foaming molding method of another embodiment of the present invention also generally includes a molten resin supplying step S10, a foaming agent supplying step S20, a fixed mixing step S30 and a foaming resin molding step S40. The molten resin supplying step S10, the foaming agent supplying step S20 and the fixed mixing step S30 have been explained above and will not be described again.

[0089] However, the foaming resin molding step S40 is to inject the foaming resin critical solution mixed and injected by the fixed type mixing part 7 in the above-mentioned fixed mixing step S30 into the molding part 9 to form a foamed molded product, such as Fig. 9 As shown, the foaming resin critical solution injected into the foaming resin injection part 13 is concentrated in the foaming resin injection part 13, and then injected into the molding part 9 with the forward and backward movement of the plunger 93 operated by the motor 95 or hydraulically. At this time, the foaming resin critical solution injected into the foaming resin injection part 13 by the fixed mixing part 7 is filled into the cylindrical shell 91 from the part close to the injection port 89 connected to the fixed mixing part 7 to the direction gradually becoming farther away. Further, as shown in FIG. Fig. 9As shown, when the injection port 89 is arranged at the front end of the shell 91, the foaming resin critical solution injected into the foaming resin injection part 13 by the fixed mixing part 7 is filled gradually from the front end of the shell 91 close to the injection port 89 to the rear end.

[0090] Then, when the motor 95 or the hydraulic device is operated to move the plunger 93 forward, the foaming resin critical solution filled in the housing 91 is injected into the molding part 9 through the injection port 92 to be molded into a foamed molded product.

[0091] Industrial Applications

[0092] According to the foaming molding device and the foaming molding method of the present invention, a high-viscosity gel-like molten resin and a low-viscosity high-pressure compressed foaming agent are introduced into a high-pressure atmosphere of more than 200 atmospheres through a high-strength fixed mixing section with multiple flow channels, and then a large amount of foaming resin critical solution is uniformly mixed. When the foaming resin critical solution is introduced or injected into a molding section or an injection mold, the number of foaming pores generated from the molding section or the injection mold can be greatly increased, and the specific gravity of the foamed molded product can be reduced, thereby achieving lightweight foamed molded products.

Claims

1. A foaming molding device, characterized in that: include: A foaming agent supply section (3) for supplying a foaming agent; a molten resin supply section (5) for supplying a molten resin; a fixed type mixing section (7) for mixing the foaming agent supplied from the foaming agent supply section (3) and the molten resin supplied from the molten resin supply section (5) together through a multi-channel flow passage (P) of an internal rod-shaped body (70) to form a foaming resin critical solution; and molding sections (8, 9) for molding a foamed molded product using the foaming resin critical solution supplied from the fixed type mixing section (7); The rod-shaped body (70) comprises: a plate-shaped body (71) formed by arranging a plurality of unit cells (80, 180) forming pores in two dimensions; and a spacer (73) connected between the plate-shaped bodies (71) so that the plate-shaped bodies (71) are laminated and the unit cells (80, 180) are arranged in three dimensions; The spacer (73) connects the adjacent plate-like bodies (71) to maintain the spacing of the pores; The plate-like body (71) is a layered structure that forms the same pattern repeatedly in two dimensions; The rod-shaped body (70) is a laminated structure in which the layered structure and the spacer (73) form a pattern that is the same as the repeated pattern of the layered structure in a direction of connection with the adjacent layered structure through the spacer (73). The rod-shaped body (70) is formed by repeatedly forming a laminated structure of the unit cell (80) and the spacer (73) in the xyz axis direction with a circle as the center. The unit cell (80) is a solid formed by overlapping three octagonal columns (Ox, Oy, Oz) with a square as an outer peripheral surface (F) and arranging each axis along the xyz axis with the circle as the center. The spacer (73) is a regular hexahedron extending on the outer peripheral surface (F) intersecting the axis and connected to the outer peripheral surface (F) of the adjacent unit cell (80), and having the outer peripheral surface (F) as one face.

2. The foaming molding device according to claim 1, characterized in that: The rod-shaped body (70) is a solid body having the same shape as the unit cell (180) and the spacer (73).

3. The foaming molding device according to any one of claims 1 to 2, characterized in that: The foaming agent supply section (3) includes one or more foaming agent injection sites into the fixed type mixing section (7).

4. The foaming molding device according to any one of claims 1 to 2, characterized in that: include: The foaming resin critical solution supplied from the fixed type mixing section (7) is fed into the molding section (8) and temporarily stored in a foaming resin storage section (11).

5. The foaming molding device according to any one of claims 1 to 2, characterized in that: include: A foaming resin injection section (13) is provided for injecting the foaming resin critical solution supplied from the fixed type mixing section (7) into the molding section (8) and temporarily storing the solution.

6. The foaming molding device according to claim 5, characterized in that: The foaming resin injection unit (13) includes a heating unit (97) for heating the foaming resin critical solution and storing it in a molten state.

7. The foaming molding device according to any one of claims 1 to 2, characterized in that: include: A foaming resin extrusion section temporarily stores the foaming resin critical solution supplied from the fixed type mixing section (7) in order to extrude it to the molding section.

8. A foaming method, characterized in that: The method comprises: a molten resin supplying step (S10) of feeding the molten resin of the molten resin supplying section (5) into the fixed type mixing section (7); a foaming agent supplying step (S20) of feeding the foaming agent of the foaming agent supplying section (3) into the fixed type mixing section (7); a fixed mixing step (S30) of causing the molten resin and the foaming agent of the rod-shaped body (70) respectively fed into the fixed type mixing section (7) to pass through the pores of the fixed type mixing section (7) in the molten resin supplying step (S10) and the foaming agent supplying step (S20), thereby causing the flow paths through which the molten resin and the foaming agent flow to be dispersed and expanded so as to be mixed into a foamed resin critical solution; and a foamed resin molding step (S40) of concentrating the foamed resin critical solution mixed and injected in the fixed mixing step (S30) into a foamed resin injection section (13) and then injecting it into a molding section (9) to be molded into a foamed molded product; The fixed mixing section (7) comprises: a plate-like body (71) formed by arranging a plurality of unit cells (80, 180) forming pores in two dimensions; a spacer (73) connecting the plate-like bodies (71) to laminate the plate-like bodies (71) so as to arrange the unit cells (80, 180) in three dimensions; The spacer (73) connects the adjacent plate-like bodies (71) to maintain the spacing of the pores; The foaming agent supplying step (S20) is that when the foaming agent is fed into the fixed type mixing section (7) at an odd foaming agent feeding position, the amount of foaming agent fed into the fixed type mixing section (7) from the foaming agent feeding position is gradually increased over time, and the foaming resin molding step (S40) is that the foaming agent content is less or no closer to the injection port (92) of the foaming resin injection section (13), and more foaming resin critical solution is filled into the foaming resin injection section (13) as it is farther away, so that the foaming resin injection section (13) is filled with the foaming resin critical solution. 13) The foaming agent content of the foaming resin critical solution injected into the molding part (9) gradually increases with the injection time, thereby gradually increasing the foaming ratio, and the filling position of the molding part (9) is moved from the surface of the foamed molded product to the center; the rod-shaped body (70) includes: a plate-shaped body (71) formed by arranging a plurality of single cells (80, 180) forming pores in two dimensions; and a spacer (73) connecting the plate-shaped bodies (71) so that the plate-shaped bodies (71) are laminated and the single cells (80, 180) are arranged in three dimensions; The spacer (73) connects the adjacent plate-like bodies (71) to maintain the spacing of the pores; The plate-like body (71) is a layered structure that forms the same pattern repeatedly in two dimensions; The rod-shaped body (70) is a laminated structure in which the layered structure and the spacer (73) form a pattern that is the same as the repeated pattern of the layered structure in a direction of connection with the adjacent layered structure through the spacer (73). The rod-shaped body (70) is formed by repeatedly forming a laminated structure of the unit cell (80) and the spacer (73) in the xyz axis direction with a circle as the center. The unit cell (80) is a solid formed by overlapping three octagonal columns (Ox, Oy, Oz) with a square as an outer peripheral surface (F) and arranging each axis along the xyz axis with the circle as the center. The spacer (73) is a regular hexahedron extending on the outer peripheral surface (F) intersecting the axis and connected to the outer peripheral surface (F) of the adjacent unit cell (80), and having the outer peripheral surface (F) as one face.

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