A process and device for polymer molding and foaming by rapid swelling of molded supercritical fluid

Abstract

In order to solve the problem of low production efficiency of supercritical foaming materials caused by long contact and penetration time between polymer and gas during supercritical compression foaming, a process of polymer molding and foaming of supercritical rapid swelling is proposed. Supercritical fluid and polymer melt can be quickly and evenly mixed in the barrel of the injection molding machine through mechanical stirring of the screw. After the homogeneous solution is injected from the injection molding machine into the mold cavity, the melt strength before foaming can be regulated and the gas solubility can be further increased through temperature regulation and further diffusion of the supercritical fluid. The above two-step staged method of melt blending and solid-state swelling foaming can ensure the rapid diffusion and swelling of the supercritical fluid in the polymer matrix. While retaining the advantages of compression foaming products, it solves the bottleneck of long swelling time caused by gas diffusion in the existing compression foaming process, significantly improves the production efficiency of compression foaming, and further promotes the industrialization of supercritical compression foaming.

Description

Technical Field

[0001] The invention relates to a process and device for polymer molding and foaming by rapid swelling of molded supercritical fluid, belonging to the technical field of supercritical polymer foaming. Background Art

[0002] At present, the preparation of microporous foam materials by supercritical foaming has attracted wide attention from new materials and related industries. This process has many advantages, such as controllable foaming ratio, high cell density and small pore size, excellent mechanical properties, wide range of applicable materials, and green environmental protection. However, the biggest bottleneck of this technology is the slow diffusion process of supercritical fluid in the polymer matrix, which requires a long time of swelling before the gas and the polymer matrix can form a relatively stable homogeneous solution, resulting in a long production cycle, that is, low production efficiency, which seriously hinders the industrialization process of preparing lightweight porous functional materials by supercritical foaming.

[0003] Patent CN103042647A discloses a method for producing a polypropylene microporous foamed thick plate. In this method, a polymer matrix is ​​first made into a thick plate with a core structure, and then placed in a flat foaming device for foaming. Since the core layer is a hollow channel, it is essentially foaming the thin plates connected together, so the problem of slow diffusion of supercritical fluid in the thin plate and long swelling time has not been improved. In addition, the size of the hollow channel becomes larger after foaming, and the integrity of the foamed plate is destroyed. When it is finally used as a product, the middle channel part needs to be cut off, that is, the product obtained from this thick plate with a core layer after foaming has defects in the overall structure.

[0004] Patent CN103895146A discloses a continuous molding device and method for polymer microcellular foam products. The method uses an extruder to fully mix the polymer melt and the foaming agent and fill it to 2-30% of the volume of the mold cavity, and then releases the pressure and foams after staying in the mold cavity for 0-10 minutes. The essence of the continuous molding process in this patent is extrusion foaming. On the basis of extrusion foaming, the improvement made is that the homogeneous solution mixed with the supercritical fluid does not foam at the outlet die, and foams by rapid pressure relief after entering the mold cavity. It improves the problem that the pressure reduction rate at the extrusion foaming die is too low and the pore size of the obtained foamed product is too large. Although the foaming can be operated continuously under this process, the homogeneous solution dissolved with the supercritical fluid stays in the mold cavity for too short a time, and the polymer materials with different characteristics have different optimal residence times in the mold cavity, so the polymer materials it is applicable to are limited. In addition, the residence time is too short so that the melt cannot be fully cooled, and the gas is easy to overflow after pressure relief and cause the collapse of the pores, which affects the product performance, and the product size is greatly limited by the size of the mold cavity. Summary of the invention

[0005] The invention provides a polymer molding and foaming process for rapidly swelling a supercritical fluid in order to solve the problem that the physical penetration process is slow when a polymer matrix contacts a supercritical fluid during the supercritical foaming process, resulting in a long foaming cycle and low production efficiency of the supercritical foamed product.

[0006] The technical scheme of the present invention is based on the following technical concepts: First, after the polymer melt and the supercritical fluid are mechanically crushed and stirred by the screw, a large number of two-phase interfaces can be formed and the diffusion distance of the supercritical fluid can be shortened, so that a homogeneous solution containing the supercritical fluid can be obtained in a short time; Second, when the polymer melt is injected into the mold and the temperature is lowered, the saturated solubility of the supercritical fluid in the polymer matrix in the mold will continue to increase, and the supercritical fluid dissolved in the early stage has a significant swelling effect on the polymer matrix, further promoting the physical diffusion rate of the supercritical fluid in the mold cavity, thereby quickly reaching saturated swelling; Third, the melt strength of the polymer matrix in the mold cavity will continue to increase as the temperature decreases, so that during foaming, the matrix has sufficient strength to wrap the gas to effectively prevent the pores from breaking and maintain a high nucleation density. Combining the above three mechanisms, making full use of the characteristics of fast diffusion of supercritical fluid in the melt state and large solubility of supercritical fluid in the high elastic state, a two-step diffusion method is used to promote the diffusion of supercritical fluid in the polymer matrix, which can significantly improve the production efficiency of molded supercritical foaming.

[0007] Technical solution:

[0008] The first aspect of the present invention provides:

[0009] A polymer molding and foaming process for rapid swelling of molded supercritical fluids, comprising the following steps:

[0010] In the first step, the polymer is melted and mixed with the supercritical fluid in the barrel of the injection molding machine and injected into the mold, and then the temperature is rapidly reduced to solidify the polymer surface;

[0011] In the second step, the polymer obtained in the first step is subjected to compression foaming treatment with a supercritical fluid to obtain a foamed material.

[0012] In one embodiment, in step 1, a homogeneous solution of a polymer melt and a supercritical fluid is formed in a barrel of an injection molding machine, and during a temperature reduction process after injection into a mold, the homogeneous solution is cooled and textures are formed on its surface.

[0013] In one embodiment, the polymer or high molecule refers to general-purpose plastics, engineering plastics or special engineering plastics that can be subjected to supercritical foaming by compression molding, including but not limited to: polystyrene, polyethylene, polypropylene, polylactic acid, polyurethane, polymethyl methacrylate, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyimide, polyphenylene sulfide, polyetherimide and other amorphous or semi-crystalline thermoplastic polymers and their copolymers or blends.

[0014] In one embodiment, the supercritical fluid includes, but is not limited to, carbon dioxide, nitrogen, water, ethanol, etc. and blends thereof.

[0015] In one embodiment, the mixing process in step 1 has a temperature range of 100-400° C. and a pressure range of 5-30 MPa.

[0016] In one embodiment, the temperature range of the compression foaming in the second step is 30-350° C., and the pressure range is 5-40 MPa.

[0017] In one embodiment, in step 1, after all mold cavities are filled with high-pressure gas, the homogeneous solution in the barrel of the injection molding machine fills the mold and then continues to be injected into another mold. The gas pressure in the mold is higher than the pressure of the gas injection system during gas injection in the injection molding machine, but lower than the back pressure of the injection molding machine when the injection molding machine injects into the mold cavity.

[0018] The second aspect of the present invention provides:

[0019] A polymer molding and foaming device for rapid swelling of molded supercritical fluid, comprising a mixing system and a molded foaming system;

[0020] Among them, the hybrid system includes:

[0021] The injection molding machine feeding barrel is connected to the injection molding machine mixing device and is used to add polymer materials;

[0022] An injection molding machine supercritical fluid injection device, connected to the injection molding machine mixing device, for adding supercritical fluid to the mixing system;

[0023] Injection molding machine mixing device, used for mixing and mold filling operations;

[0024] The compression foaming system includes:

[0025] The mold comprises an upper mold and a lower mold. When the upper mold and the lower mold are closed, a mold cavity is formed inside; and a temperature control system is provided in the mold cavity.

[0026] In one embodiment, the temperature control system is a heating and / or cooling system.

[0027] In one embodiment, a gas chamber is provided inside the upper mold or the lower mold, and the gas chamber is connected to a gas container.

[0028] In one embodiment, the gas chamber is in communication with the mold cavity via a gas addition plate.

[0029] In one embodiment, the gas addition plate includes a fixed plate, a movable plate that can move up and down is provided on the side of the fixed plate facing away from the mold cavity, and a raised pattern is provided on the side of the movable plate facing the mold cavity. When the movable plate moves toward the mold cavity, the raised pattern can pass through the fixed plate; ventilation holes are also distributed on the movable plate and the fixed plate.

[0030] In one embodiment, the gas chamber is connected to the gas container via the gas inlet of the gas chamber, and a plurality of gas outlets are further provided on the gas chamber.

[0031] In one embodiment, the gas container is connected to the gas inlet via a control valve and a booster pump in sequence.

[0032] In one embodiment, the compression foaming system includes at least two molds, and the injection molding machine mixing device can be connected to any one of the molds. It also includes a displacement device for controlling the movement of the injection molding machine mixing device, which can switch the injection molding machine mixing device from connection with one mold to connection with another mold.

[0033] In one embodiment, the discharge port of the mixing device of the injection molding machine is also provided with an injection port control valve of the injection molding machine, which is used to control the opening and closing of the discharge process port.

[0034] In one embodiment, a feed control device of the mold is also provided on the mold, which is connected to the discharge port of the mixing device of the injection molding machine and is used to control the opening and closing of the feed port of the mold.

[0035] In one embodiment, the mold cavity is coated with a Teflon coating.

[0036] The third aspect of the present invention provides:

[0037] The above polymer molding and foaming device is used in the manufacture of supercritical foaming materials.

[0038] A fourth aspect of the present invention provides:

[0039] A continuous compression foaming production process comprises the following steps: mixing a polymer and a supercritical fluid through a mixer, injecting the mixture into a first mold, injecting a homogeneous solution of the polymer and the supercritical fluid into a second mold, and starting compression foaming operation in the first mold.

[0040] A fifth aspect of the present invention provides:

[0041] A continuous molding foaming production device, comprising: a mixing system, at least two foaming devices; a first mold and a second mold;

[0042] The mixing system is used to mix the polymer with the supercritical fluid and inject it into the mold;

[0043] A displacement device is also included for controlling the position of the mixing system to move from a joining position of one foaming device to a joining position of another foaming device.

[0044] In one embodiment, the foaming equipment refers to a foaming mold or a foaming machine.

[0045] Beneficial Effects

[0046] 1. The supercritical fluid and polymer melt can be quickly and evenly mixed by mechanical stirring in the screw. The cooling in the mold cavity and the further diffusion of the supercritical fluid can achieve the regulation of the strength of the foaming matrix and further increase the solubility of the supercritical fluid. The above two-step method and staged method can ensure the rapid diffusion and swelling of the supercritical fluid in the polymer matrix, solve the bottleneck of long swelling time caused by slow gas diffusion in the molded foaming production, and significantly improve the production efficiency of the molded foaming;

[0047] 2. While solving the above problems, this solution also retains the advantages of molded foam products, such as: the product has a large foaming ratio, a controllable range (1 to 50 times), a large cell density and a small pore size, and a wide range of applicable materials;

[0048] 3. This method is also suitable for producing products with different foaming ratios and special-shaped profiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 : Installation diagram;

[0050] Figure 2 : Top view of the device at the connection between the mold cavity and the air chamber;

[0051] Figure 3 : Cross-sectional view of the device at the connection between the mold cavity and the air chamber;

[0052] Figure 4 : SEM photo of the material prepared in Example 1;

[0053] Figure 5 : SEM photo of the material prepared in Comparative Example 1;

[0054] Figure 6 : SEM photo of the material prepared in Comparative Example 2;

[0055] Figure 7 : SEM photo of the material prepared in Comparative Example 3;

[0056] 1: Injection molding machine feeding barrel:

[0057] 2: Supercritical fluid injection device for injection molding machine,

[0058] 3: Injection molding machine mixing device;

[0059] 4: displacement device;

[0060] 5: Injection molding machine injection port control valve;

[0061] 6: Mould feeding control device;

[0062] 7: Upper mold;

[0063] 8: lower die;

[0064] 9: mold cavity;

[0065] 10: First air chamber;

[0066] 11: Second air chamber;

[0067] 12: First gas adding plate;

[0068] 13: Second gas adding plate;

[0069] 14: Booster pump;

[0070] 15: Control valve;

[0071] 16: Gas container;

[0072] 17: Air inlet of the air chamber;

[0073] 18: Exhaust port;

[0074] 19: vent hole;

[0075] 20: Raised lines;

[0076] 21: fixed plate;

[0077] 22: Movable board. DETAILED DESCRIPTION

[0078] In order to solve the problem of low production efficiency of supercritical foaming materials caused by long contact and penetration time between polymer and gas during supercritical compression foaming, a process of polymer molding and foaming of supercritical rapid swelling is proposed. Supercritical fluid and polymer melt can be quickly and evenly mixed in the barrel of the injection molding machine through mechanical stirring of the screw. After the homogeneous solution is injected from the injection molding machine into the mold cavity, the melt strength before foaming can be regulated and the gas solubility can be further increased through temperature regulation and further diffusion of the supercritical fluid. The above two-step staged method of melt blending and solid-state swelling foaming can ensure the rapid diffusion and swelling of the supercritical fluid in the polymer matrix. While retaining the advantages of compression foaming products, it solves the bottleneck of long swelling time caused by gas diffusion in the existing compression foaming process, significantly improves the production efficiency of compression foaming, and further promotes the industrialization of supercritical compression foaming.

[0079] The supercritical molded foaming production device provided by the present invention is as follows Figure 1 shown.

[0080] It is mainly composed of a mixing system and a molding foaming system.

[0081] Hybrid systems include:

[0082] The injection molding machine feeding barrel 1 is connected to the injection molding machine mixing device 3 and is used to add polymer materials. The polymer here can be any general plastic, engineering plastic or special engineering plastic that can produce foaming materials, and can be amorphous or semi-crystalline thermoplastic polymers such as polystyrene, polyethylene, polypropylene, polylactic acid, polyurethane, polymethyl methacrylate, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyimide, polyphenylene sulfide, polyetherimide and their copolymers or blends. The resin raw material usually also includes processing aids, such as masterbatch, inorganic filler, flame retardant, nucleating agent, etc., which are first premixed with the resin raw material and then added to the injection molding machine. The shape of the material of the polymer used here is not particularly limited, and can be granular, sheet-like, etc.

[0083] The supercritical fluid injection device 2 of the injection molding machine is connected to the mixing device 3 of the injection molding machine, and is used to add supercritical fluid to the mixing system. The injection device can also include a gas container, a metering system, a matching interface, an injection booster pump, a control valve, etc.; a one-way valve (not marked) is installed between it and the feed, and a one-way valve (not marked) is installed between it and the die; the supercritical fluid can be one or more of green and environmentally friendly fluids such as carbon dioxide, nitrogen, and water.

[0084] The mixing device 3 of the injection molding machine is used for the mixing and mold filling operation, and mechanically mixes the polymer and the supercritical fluid (or other auxiliary additives) by mixing.

[0085] In order to achieve production continuity of compression foaming, at least two molds may be included, and the injection molding machine mixing device 3 may be connected to any one of the molds. A displacement device 4 for controlling the movement of the injection molding machine mixing device 3 may be included, and the injection molding machine mixing device 3 may be switched from connection with one mold to connection with another mold, and the position of the injection molding machine may be quickly adjusted so that the injection molding machine mixing device 3 may feed materials to different molds.

[0086] In one embodiment, an injection molding machine injection port control valve 5 is also provided on the discharge port of the injection molding machine mixing device 3, which is used to control the opening and closing of the discharge process port; a mold feed control device 6 is also provided on the mold, which is connected to the discharge port of the injection molding machine mixing device 3 and is used to control the opening and closing of the mold feed port.

[0087] The foaming system includes a mold for compression foaming, and the number of the molds can be one or more than two. When one is used, intermittent production is achieved, and when two or more are used, overall continuous production can be achieved.

[0088] like Figure 1 The structure of the mold for compression foaming includes an upper mold and a lower mold. When the upper mold 7 and the lower mold 8 are closed, a mold cavity 9 is formed inside. The mold cavity is provided with a rapid cooling system (for rapid cooling of the polymer melt) and a Teflon coating; a feed control device 6 is arranged on the lower mold 8; a first air chamber 10 is arranged in the upper mold 7, and a second air chamber 11 is arranged in the lower mold 8; the first air chamber 10 and the second air chamber 11 are connected to a gas container 16;

[0089] The first air chamber 10 is connected to the mold cavity 9 through the first gas adding plate 12, and the second air chamber 11 is connected to the mold cavity 9 through the second gas adding plate 13;

[0090] The gas addition plate includes a fixed plate 21, and a movable plate 22 that can move up and down is provided on the side of the fixed plate 21 facing away from the mold cavity 9, and a raised pattern 20 is provided on the side of the movable plate 22 facing the mold cavity 9. When the movable plate 22 moves toward the mold cavity 9, the raised pattern 20 can pass through the fixed plate 21; vents 19 (vents installed at the connection between the air chamber and the mold cavity) are also distributed on the movable plate 22 and the fixed plate 21. In the technical scheme in which vents are distributed on both the fixed plate and the movable plate, the movable plate has large through holes and the fixed plate has dense small through holes, which facilitates the discharge of gas inside the mold cavity when the melt fills the mold and can maintain a certain back pressure in the mold cavity to suppress the overflow of gas in the melt.

[0091] The first air chamber 10 and the second air chamber 11 are connected to the gas container 16 through the air inlet 17 of the air chamber, and the first air chamber 10 and the second air chamber 11 are also provided with an exhaust port 18; in addition, the gas container 16 is preferably connected to the air inlet through the control valve 15 and the booster pump 14 in sequence. The gas container 16 is filled with a supercritical fluid for injection into the mold cavity 9.

[0092] The following is a further explanation of the operation process:

[0093] Add the resin, foaming agent, various additives and supercritical fluid to the injection molding machine (with an automatic lifting platform to quickly adjust the position) in a certain proportion and mix them thoroughly. The temperature range during the mixing process is 100-400°C and the pressure range is 5-30MPa to form a uniform phase (this is the first step for the supercritical fluid to diffuse in the polymer matrix). Then quickly inject the homogeneous solution into the mold cavity filled with high temperature and high-pressure supercritical fluid. Before and after injection, keep the gas pressure in the mold cavity higher than the pressure of the gas injection system during gas injection in the injection molding machine to prevent foaming due to phase separation during injection; at the same time, the gas pressure in the mold cavity should be lower than the back pressure of the injection molding machine when the injection molding machine injects into the mold cavity to ensure that the homogeneous solution can be smoothly injected into the mold cavity.

[0094] When the homogeneous solution is injected into the mold, the movable plates 22 on the first gas adding plate 12 and the second gas adding plate 13 need to be extended toward the mold cavity 9, so that the first gas adding plate 12 and the second gas adding plate 13 have raised lines 20 on the side facing the mold cavity 9. The presence of the raised lines 20 will cause stripes to be pressed out on the surface of the polymer.

[0095] After the injection is completed, the cavity is closed and the temperature is rapidly reduced to solidify the polymer surface. The injection molding machine connects to the next cavity for injection molding.

[0096] For the previous cavity, after the surface of the polymer is initially hardened, the movable plate of the gas-added plate descends, exposing the upper and lower surfaces of the polymer with concave and convex patterns to increase the surface area in contact with the gas. At this time, the supercritical gas continues to diffuse into the polymer matrix (the second step of diffusion). The temperature range of compression foaming is 30-350°C, and the pressure range is 5-40MPa. After about 0-30 minutes, the compression molding machine (with a heating and cooling temperature control system) releases the pressure through the exhaust valve or the mold opening, and opens the mold to allow the product to pop out, ultimately obtaining a microporous foam material.

[0097] In the present invention, “gas chamber”, unless otherwise specified, refers to both the first gas chamber 10 and the second gas chamber 11 ; “gas addition plate”, unless otherwise specified, refers to both the first gas addition plate 12 and the second gas addition plate 13 .

[0098] Example 1

[0099] Taking the production of polypropylene foam material as an example, polypropylene and supercritical liquid carbon dioxide are first mixed in a mass ratio of 100:3 and heated to 200°C in the injection molding system. First, 20MPa of high-pressure carbon dioxide is filled into the mold cavity, and then the homogeneous solution in the injection molding system is injected into the molded foaming mold. The raised lines 20 in the mold are parallel to each other, with a line depth of 0.5mm, a spacing of 3mm between adjacent lines, and a line width of 1mm. After the mold is filled with polymer, it is quickly cooled to room temperature to form lines on the polymer surface to increase the surface area. The average cooling rate is about 35-45°C / min. After the surface is solidified, the movable plate is moved in the direction away from the mold cavity 9 so that the lines can contact with the high-pressure carbon dioxide and continue to swell for 20 minutes, and then the pressure is released for foaming.

[0100] Example 2

[0101] Taking the production of polylactic acid foaming material as an example, polylactic acid and supercritical liquid carbon dioxide are first mixed in a mass ratio of 100:3 and heated to 200°C in the injection molding system. First, 20MPa of high-pressure carbon dioxide is filled into the mold cavity, and then the homogeneous solution in the injection molding system is injected into the molded foaming mold. The raised lines 20 in the mold are parallel to each other, with a line depth of 0.5mm, an interval of 3mm between adjacent lines, and a line width of 1mm. After the mold is filled with polymer, it is quickly cooled to room temperature to form lines on the polymer surface to increase the surface area. The average cooling rate is about 35-45°C / min. After the surface is solidified, the movable plate is moved in the direction away from the mold cavity 9 so that the lines can contact with the high-pressure carbon dioxide and continue to swell for 20 minutes, and then the pressure is released for foaming.

[0102] Example 3

[0103] Taking the production of polyethylene terephthalate foaming material as an example, polyethylene terephthalate and supercritical liquid carbon dioxide are first mixed in a mass ratio of 100:2 and heated to 300°C in the injection molding system. First, 20MPa of high-pressure carbon dioxide is filled into the mold cavity, and then the homogeneous solution in the injection molding system is injected into the molded foaming mold. The raised lines 20 in the mold are parallel to each other, with a line depth of 0.5mm, an interval of 3mm between adjacent lines, and a line width of 1mm. After the mold is filled with polymer, it is quickly cooled to room temperature to form lines on the polymer surface to increase the surface area. The average cooling rate is about 35-45°C / min. After the surface is solidified, the movable plate is moved in the direction away from the mold cavity 9 so that the lines can contact with the high-pressure carbon dioxide and continue to swell for 20 minutes, and then the pressure is released for foaming.

[0104] Comparative Example 1

[0105] The difference from Example 1 is that no raised pattern 20 is provided in the mold, and the foaming process is directly performed in the mold after the addition and cooling are completed.

[0106] Comparative Example 2

[0107] The difference from Example 1 is that the polypropylene is directly subjected to supercritical foaming without premixing the polymer and carbon dioxide and cooling the polymer.

[0108] Comparative Example 3

[0109] The difference from Example 1 is that after the mold is filled with the polymer, the polymer is cooled down by natural cooling.

[0110] The performance characterization results of the foamed material prepared by the above method are as follows:

[0111]

[0112] The SEM characterization results of the above foaming materials are as follows Figure 2-Figure 7 As shown in the figure, it can be seen that the foamed material prepared by the present invention has a smaller average cell diameter and a higher cell density.

[0113] It can be seen from the table that the two-step method of the present invention can be used to prepare a foaming material with better performance. At the same time, through the surface texture treatment, the contact area between the supercritical liquid and the polymer is increased, the swelling efficiency of the supercritical fluid is increased, and the foaming performance of the foaming material is better. Through the above-mentioned equipment and method, the foaming ratio can be effectively improved, the average diameter of the pores can be reduced, the pore density can be increased, and the compression strength of the foaming material can be improved.

Claims

1. A process for polymer molding and foaming by rapid swelling of molded supercritical fluid, characterized in that: The devices used include a mixing system and a compression foaming system; Among them, the hybrid system includes: An injection molding machine feeding barrel (1) connected to an injection molding machine mixing device (3) for adding polymer material; An injection molding machine supercritical fluid injection device (2), connected to the injection molding machine mixing device (3), for adding supercritical fluid to the mixing system; The injection molding machine mixing device (3) is used for mixing and filling the mold; The compression foaming system includes: The mold comprises an upper mold and a lower mold, wherein the upper mold (7) and the lower mold (8) are closed to form a mold cavity (9) inside; the mold cavity is provided with a cooling temperature control system; A first air chamber (10) is provided in the upper mold (7), and a second air chamber (11) is provided in the lower mold (8); the first air chamber (10) and the second air chamber (11) are connected to a gas container (16); the first air chamber (10) is connected to the mold cavity (9) via a first gas introduction plate (12), and the second air chamber (11) is connected to the mold cavity (9) via a second gas introduction plate (13); The gas adding plate includes a fixed plate (21), a movable plate (22) that can move up and down is provided on the side of the fixed plate (21) facing away from the mold cavity (9), and a convex pattern (20) is provided on the side of the movable plate (22) facing the mold cavity (9). When the movable plate (22) moves toward the mold cavity (9), the convex pattern (20) passes through the fixed plate (21); vent holes (19) are also distributed on the movable plate (22) and the fixed plate (21), and the following steps are included: step 1, melting a polymer and mixing it with a supercritical fluid and injecting it into the mold cavity, and then rapidly cooling it to solidify the surface of the polymer; step 2, subjecting the polymer obtained in step 1 to a mold compression foaming treatment with the supercritical fluid to obtain a foaming material; In the first step, the surface of the polymer is textured during a rapid cooling process.

2. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 1, characterized in that: The first air chamber (10) and the second air chamber (11) are connected to the gas container (16) via the air inlet (17) of the air chamber, and the first air chamber (10) and the second air chamber (11) are also provided with an exhaust port (18) respectively; the gas container (16) is connected to the air inlet via the control valve (15) and the booster pump (14) in sequence.

3. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 1, characterized in that: The compression foaming system comprises at least two molds, an injection molding machine mixing device (3) is connected to any one of the molds, and the mixing system further comprises a displacement device (4) for controlling the movement of the injection molding machine mixing device (3) to switch the injection molding machine mixing device (3) from being connected to one mold to being connected to another mold.

4. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 3, characterized in that: The discharge port of the injection molding machine mixing device (3) is also provided with an injection molding machine injection port control valve (5) for controlling the opening and closing of the discharge port.

5. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 3, characterized in that: The mold is also provided with a mold feed control device (6) which is connected to the discharge port of the injection molding machine mixing device (3) and is used to control the opening and closing of the mold feed port; the mold cavity is coated with a Teflon coating.

6. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 1, characterized in that: The polymer is polystyrene, polyethylene, polypropylene, polylactic acid, polyurethane, polymethyl methacrylate, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyimide, polyphenylene sulfide, polyetherimide, or a blend thereof; the supercritical fluid is carbon dioxide, nitrogen, water, ethanol, or a blend thereof.

7. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 1, characterized in that: The temperature range of the mixing process in step 1 is 100-400°C and the pressure range is 5-30 MPa; the temperature range of the compression foaming in step 2 is 30-350°C and the pressure range is 5-40 MPa.

8. The process for polymer molding and foaming by rapid swelling of molded supercritical fluid according to claim 3, characterized in that: In step 1, after injecting the mixture into one mold, continue injecting the mixture into the other mold.

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