Device for preparing supercritical foaming material and method for preparing foaming material

Abstract

The present invention relates to a device for preparing supercritical foaming materials and a method for preparing foaming materials. The device for preparing supercritical foaming materials includes a kettle body, a supercritical fluid circulation component, a high-pressure injection head and a foaming mold; the kettle body is provided with an infiltration chamber, a pressurization chamber and a mixing extrusion chamber from top to bottom; the infiltration chamber is provided with a first air inlet for introducing a supercritical fluid and a first air outlet for discharging the supercritical fluid, the pressurization chamber is provided with a heating element, and the mixing extrusion chamber is provided with a screw extrusion component. The present invention separates the infiltration process and the extrusion process of the supercritical fluid of the foaming material, which is conducive to controlling the pressure and temperature of the supercritical fluid during the infiltration process. At the same time, the foaming material needs to be melted in the pressurization chamber after the infiltration process, which further improves the uniformity of the distribution of the supercritical fluid inside the foaming material.

Description

Technical Field

[0001] The present invention relates to the technical field of foaming materials, in particular to a device for preparing supercritical foaming materials and a method for preparing the foaming materials. Background Art

[0002] Supercritical foaming molding is a physical foaming molding technology, and also a microcellular foaming molding technology. In the injection molding, extrusion and blow molding processes, supercritical carbon dioxide or nitrogen or other gases are first injected into a special plasticizing device to allow the gas to be fully and evenly mixed / diffused with the molten raw materials to form a single-phase mixed sol. The sol is then introduced into the mold cavity or extrusion die to cause a large pressure drop in the sol, thereby causing the gas to precipitate and form a large number of bubble nuclei. In the subsequent cooling and molding process, the bubble nuclei inside the sol continue to grow and form, and finally a microcellular foamed plastic product is obtained.

[0003] Taking TPU (thermoplastic polyurethane elastomer) foam particles as an example, the application of TPU foam particles in the fields of shoe soles is an inevitable development trend and has huge market value. The field of shoe materials is only a stepping stone for the application of this material. After mature application, it can be used in aerospace, transportation, cushioning, sports, medical and other fields. At present, in the process of preparing TPU foam materials, continuous extrusion foaming efficiency is relatively high and suitable for industrial mass production, but the supercritical fluid needs to be released through a screw to achieve a good penetration effect. In this way, the high pressure required to maintain the supercritical fluid state will easily cause greater damage to the screw, so the strength requirements of the screw are relatively high. And because the foaming material is always kept in a molten state during the continuous extrusion process, it is difficult to adjust and control process parameters such as the pressure, temperature, and pressure release rate of supercritical carbon dioxide during the foaming process, which makes it difficult to achieve a balance in the quality of the finished foamed material. Summary of the Invention

[0004] In order to overcome the defects of the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a device for preparing supercritical foaming material and a method for preparing foaming material, which is suitable for industrial mass production, reduces the damage of high pressure to extrusion equipment and is convenient for regulating the process parameters during the foaming process.

[0005] In order to solve the above technical problems, the present invention adopts a technical solution as follows: a device for preparing supercritical foaming material, comprising a kettle, a supercritical fluid circulation component, a high-pressure injection head and a foaming mold;

[0006] The interior of the kettle is provided with an infiltration chamber, a pressurization chamber and a mixing and extrusion chamber in sequence from top to bottom;

[0007] The permeation chamber is provided with a first air inlet for introducing a supercritical fluid and a first air outlet for discharging the supercritical fluid, the pressurization chamber is provided with a heating element, and the mixing and extrusion chamber is provided with a screw extrusion assembly;

[0008] The supercritical fluid circulation component is connected to the first air inlet and the first air outlet of the osmosis chamber at the same time, and the supercritical fluid circulation component is used to introduce circulating supercritical fluid into the osmosis chamber;

[0009] One end of the high-pressure injection head is connected to the mixing and extrusion cavity, and the other end is connected to the foaming mold. The high-pressure injection head is used to mix and extrude the molten foaming material in the cavity;

[0010] The foaming mold is provided with a pressure relief valve which can adjust the internal pressure of the foaming mold.

[0011] A first partition is provided between the osmotic chamber and the pressurizing chamber, a first switch assembly is provided on the first partition, and a second partition is provided between the pressurizing chamber and the mixing and extruding chamber, a second switch assembly is provided on the first partition.

[0012] Among them, the upper end face and the lower end face of the first partition are both semi-spherical, the middle part of the first partition is provided with a first opening for allowing the foaming material to pass through, the first switch component is arranged at the first opening, and a reinforcing element is provided at the connection between the first opening and the first switch component; the upper end face of the second partition is semi-spherical, the lower end face of the second partition is planar, the middle part of the second partition is provided with a second opening for allowing the foaming material to pass through, the second switch component is arranged at the second opening, and a reinforcing element is provided at the connection between the second opening and the second switch component.

[0013] Among them, the supercritical fluid circulation component includes a gas storage tank, a delivery pump, a circulation storage tank, a gas pressure pump, a preheating tank, an air intake pump and a circulation pump. The gas storage tank, the delivery pump, the circulation storage tank, the gas pressure pump and the preheating tank are connected in sequence. The preheating tank is connected to the first air inlet of the osmosis chamber through the air intake pump, and the first air outlet of the osmosis chamber is connected to the circulation storage tank through the circulation pump.

[0014] Wherein, the mixing extrusion cavity is provided with a second air inlet and a second air outlet, the second air inlet is connected to the first air outlet through a pipeline, and the second air outlet is connected to the circulation pump through a pipeline.

[0015] The foaming mold includes an upper mold, a lower mold and a forming mold. The forming mold is arranged between the upper mold and the lower mold. The high-pressure injection head is passed through the upper mold into the forming mold. The pressure relief valve is passed through the lower mold into the forming mold.

[0016] The foaming mold further includes a temperature control component, which is arranged between the forming mold and the upper mold and the lower mold. The temperature control component is used to quickly cool or heat the foaming material in the forming mold.

[0017] The beneficial effects of the present invention are as follows: the infiltration process and the extrusion process of the supercritical fluid of the foaming material are separated, which is conducive to controlling the pressure and temperature of the supercritical fluid during the infiltration process. At the same time, the foaming material needs to be melted in the pressurized chamber after the infiltration process, which further improves the uniformity of the distribution of the supercritical fluid inside the foaming material; the pressure in the mixing extrusion chamber is relatively low, and there is no need to pass the supercritical fluid into the molten foaming material through the screw extrusion assembly, so the pressure and damage to the screw extrusion assembly during the extrusion process can be greatly reduced, which is suitable for industrial mass production.

[0018] Another technical solution adopted by the present invention is: a method for preparing a supercritical foam material using the above-mentioned device for preparing a supercritical foam material, comprising the following steps:

[0019] Step 1: Passing supercritical fluid into the kettle, high-pressure injection head and foaming mold to clean and expel air, then adding foaming material into the permeation cavity and heating the kettle as a whole to make the temperature of the kettle higher than the critical temperature of the supercritical fluid;

[0020] Step 2: The pressurized supercritical fluid is introduced into the permeation chamber through the supercritical fluid circulation assembly and circulated for a certain period of time;

[0021] Step 3: Stop the supercritical fluid from flowing into the osmotic chamber and allow the foaming material in the osmotic chamber to fall into the pressurizing chamber. The pressurizing chamber is heated and pressurized separately by the heating element in the pressurizing chamber to melt the foaming material.

[0022] Step 4: The molten foaming material is introduced into the mixing and extrusion chamber, and the molten foaming material is stirred and extruded to the high-pressure injection head by the screw extrusion assembly in the mixing and extrusion chamber;

[0023] Step 5. The high-pressure pouring head pours the molten foaming material into the foaming mold. At the same time, during the pouring process, the pressure in the foaming mold is controlled by the pressure relief valve to keep consistent with the pressure of the high-pressure pouring head until the pouring is completed. Then, the pressure in the foaming mold is released to normal pressure through the pressure relief valve to obtain the supercritical foaming material.

[0024] Wherein, in the step 1, after the kettle body is heated as a whole, the temperature of the kettle body is lower than the melting temperature of the foaming material.

[0025] Wherein, the supercritical fluid is a supercritical fluid of carbon dioxide or nitrogen, and the foaming material is a thermoplastic polyurethane elastomer or ethylene-vinyl acetate copolymer.

[0026] The beneficial effect of the present invention is that after the foaming material is infiltrated by the supercritical fluid, the distribution uniformity of the supercritical fluid in the foaming material can be further improved during the melting process, thereby ensuring that the pore size of the foamed micropores in the finally obtained supercritical foaming material can be more uniform, thereby achieving balanced and controllable quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shown is a schematic structural diagram of an apparatus for preparing a supercritical foaming material in a specific embodiment of the present invention;

[0028] Figure 2 The figure shows a schematic diagram of the structure inside the kettle body in a specific embodiment of the present invention;

[0029] Description of labels:

[0030] 1. Kettle body; 11. Permeation chamber; 111. First air inlet; 112. First air outlet; 113. First partition; 12. Pressurization chamber; 121. Heating element; 122. Second partition; 13. Mixing extrusion chamber; 131. Screw extrusion assembly; 132. Second air inlet; 133. Second air outlet 2. Supercritical fluid circulation assembly; 21. Gas storage tank; 22. Delivery pump; 23. Circulation storage tank; 24. Gas pressure pump; 25. Preheating tank; 26. Air intake pump; 27. Circulation pump; 3. High-pressure injection head; 4. Foaming mold; 41. Pressure relief valve; 42. Upper mold; 43. Lower mold; 44. Molding mold; 45. Temperature control assembly. DETAILED DESCRIPTION

[0031] To illustrate the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and accompanying drawings.

[0032] Please refer to Figures 1 to 2 As shown, a device for preparing supercritical foaming materials of the present invention includes a kettle body 1, a supercritical fluid circulation component 2, a high-pressure injection head 3 and a foaming mold 4;

[0033] The interior of the kettle body 1 is provided with an infiltration chamber 11, a pressurization chamber 12 and a mixing and extrusion chamber 13 in sequence from top to bottom;

[0034] The permeation chamber 11 is provided with a first air inlet 111 for introducing the supercritical fluid and a first air outlet 112 for discharging the supercritical fluid. The pressurization chamber 12 is provided with a heating element 121. The mixing and extrusion chamber 13 is provided with a screw extrusion assembly 131.

[0035] The supercritical fluid circulation component 2 is connected to the first air inlet 111 and the first air outlet 112 of the osmosis chamber 11 at the same time, and the supercritical fluid circulation component 2 is used to introduce the circulating supercritical fluid into the osmosis chamber 11;

[0036] One end of the high-pressure injection head 3 is connected to the mixing and extrusion cavity 13, and the other end is connected to the foaming mold 4. The high-pressure injection head 3 is used to mix and extrude the molten foaming material in the cavity 13;

[0037] The foaming mold 4 is provided with a pressure relief valve 41 which can adjust the internal pressure of the foaming mold 4 .

[0038] When using the above-mentioned device, it is necessary to first introduce a gas at room temperature and pressure, such as carbon dioxide or nitrogen, which is the same as the supercritical fluid used for foaming later, into the kettle body 1, the high-pressure injection head 3 and the foaming mold 4 to clean and exhaust the air, so as to ensure that the foaming process will not be disturbed by the air. Then, the foaming material, such as TPU particles or EVA particles, is put into the infiltration cavity 11 of the kettle body 1, and the infiltration cavity 11 and the boosting cavity 12 are kept relatively closed. Then, the kettle body 1 is heated as a whole so that the temperature of the kettle body 1 is greater than the critical temperature of the supercritical fluid, so as to ensure that the supercritical fluid can maintain a supercritical state when flowing in the kettle body 1; then, the supercritical fluid circulation component 2 is used to circulate the supercritical fluid. The pressurized supercritical fluid is introduced into the infiltration chamber 11 and circulated for a certain period of time. During this process, it is necessary to ensure that the supercritical fluid is maintained in a supercritical state and the pressure is maintained for a certain period of time. The supercritical fluid will gradually penetrate into the interior of the foaming material as the circulation process progresses. There is a large amount of saturated supercritical fluid inside the foaming material. After a certain period of penetration, the supercritical fluid is stopped from being introduced into the infiltration chamber 11, and the foaming material of the infiltration chamber 11 is dropped into the boosting chamber 12. The boosting chamber 12 is then heated and pressurized separately by the heating element 121 in the boosting chamber 12. During the heating and pressurization process of the boosting chamber 12, the supercritical fluid The state of the body will not change. At the same time, the pressurization can also reduce the melting temperature of the foaming material, making it reach the molten state faster. When the foaming material melts, the supercritical fluid can further flow in the molten foaming material, thereby achieving a more uniform diffusion effect. When the foaming material is completely melted, the molten foaming material is passed into the mixing extrusion chamber 13. At this time, since the pressure in the mixing extrusion chamber 13 is reduced, and there is no need to pass the supercritical fluid through the screw extrusion assembly 131 to the molten foaming material, the pressure and damage to the screw extrusion assembly 131 during the extrusion process can be greatly reduced, and the screw extrusion assembly 131 can also be used. It can operate relatively quickly to ensure that the foaming material can be extruded into the high-pressure infusion head 3 before cooling; finally, the high-pressure infusion head 3 infuses the molten foaming material into the foaming mold 4, and at the same time, during the infusion process, the pressure in the foaming mold 4 is controlled to be consistent with the pressure of the high-pressure infusion head 3 through the pressure relief valve 41 until the infusion is completed, and then the pressure in the foaming mold 4 is quickly released to normal pressure through the pressure relief valve 41. During the pressure relief process, under a relatively high pressure difference, the supercritical fluid in the foaming material expands rapidly and forms a large number of bubble nuclei, and due to the considerable pressure difference, the bubble nuclei expand and grow, and finally a supercritical foaming material is obtained.

[0039] A method for preparing a supercritical foam material using the above-mentioned device for preparing a supercritical foam material comprises the following steps:

[0040] Step 1: Passing supercritical fluid into the kettle 1, high-pressure injection head 3 and foaming mold 4 to clean and expel air, then adding foaming material into the permeation cavity 11 and heating the kettle 1 as a whole to make the temperature of the kettle 1 greater than the critical temperature of the supercritical fluid;

[0041] Step 2: The pressurized supercritical fluid is introduced into the osmotic chamber 11 through the supercritical fluid circulation assembly 2 and circulated for a certain period of time;

[0042] Step 3: Stop the supercritical fluid from flowing into the osmotic chamber 11 and allow the foaming material in the osmotic chamber 11 to fall into the pressurizing chamber 12. The pressurizing chamber 12 is heated and pressurized separately by the heating element 121 in the pressurizing chamber 12, so that the foaming material becomes a molten state.

[0043] Step 4: The molten foaming material is introduced into the mixing and extrusion chamber 13 , and the molten foaming material is stirred and extruded to the high-pressure injection head 3 by the screw extrusion assembly 131 in the mixing and extrusion chamber 13 ;

[0044] Step 5. The high-pressure pouring head 3 pours the molten foaming material into the foaming mold 4. At the same time, during the pouring process, the pressure in the foaming mold 4 is controlled by the pressure relief valve 41 to be consistent with the pressure of the high-pressure pouring head 3 until the pouring is completed. Then, the pressure in the foaming mold 4 is released to normal pressure through the pressure relief valve 41 to obtain a supercritical foaming material.

[0045] In the step 1, after the kettle body 1 is heated as a whole, the temperature of the kettle body 1 is lower than the melting temperature of the foaming material.

[0046] The supercritical fluid is a supercritical fluid of carbon dioxide or nitrogen, and the foaming material is a thermoplastic polyurethane elastomer or ethylene-vinyl acetate copolymer.

[0047] Example 1

[0048] like Figure 1 and 2 As shown, a device for preparing supercritical foaming materials includes a kettle body 1, a supercritical fluid circulation component 2, a high-pressure injection head 3 and a foaming mold 4;

[0049] The interior of the kettle body 1 is provided with an infiltration chamber 11, a pressurization chamber 12 and a mixing and extrusion chamber 13 in sequence from top to bottom;

[0050] The osmotic chamber 11 is provided with a first air inlet 111 for introducing a supercritical fluid and a first air outlet 112 for discharging the supercritical fluid. The pressurizing chamber 12 is provided with a heating rod. The mixing extrusion chamber 13 is provided with a screw extrusion assembly 131. The screw extrusion assembly 131 includes a main shaft, blades arranged around the main shaft, and a motor for driving the screw.

[0051] The supercritical fluid circulation component 2 is connected to the first air inlet 111 and the first air outlet 112 of the osmosis chamber 11 at the same time, and the supercritical fluid circulation component 2 is used to introduce the circulating supercritical fluid into the osmosis chamber 11;

[0052] One end of the high-pressure injection head 3 is connected to the mixing and extrusion cavity 13, and the other end is connected to the foaming mold 4. The high-pressure injection head 3 is used to mix and extrude the molten foaming material in the cavity 13;

[0053] The foaming mold 4 is provided with a pressure relief valve 41 which can adjust the internal pressure of the foaming mold 4 .

[0054] A first partition 113 is provided between the osmotic chamber 11 and the pressurizing chamber 12, with a first switch assembly mounted on the first partition 113. A second partition 122 is provided between the pressurizing chamber 12 and the mixing and extrusion chamber 13, with a second switch assembly mounted on the first partition 113. The first partition 113 between the osmotic chamber 11 and the pressurizing chamber 12 provides isolation and protection, while the first switch assembly is a switchable valve that allows the foaming material to fall from the osmotic chamber 11 into the pressurizing chamber 12. The second partition 122 serves the same function as the first partition 113.

[0055] The upper end face and the lower end face of the first partition 113 are both semi-spherical, and a first opening for allowing the foaming material to pass through is opened in the middle of the first partition 113, and the first switch component is arranged at the first opening, and a reinforcing element is provided at the connection between the first opening and the first switch component, and the reinforcing element is a rib; the upper end face of the second partition 122 is semi-spherical, and the lower end face of the second partition 122 is planar, and a second opening for allowing the foaming material to pass through is opened in the middle of the second partition 122, and the second switch component is arranged at the second opening, and a reinforcing element is provided at the connection between the second opening and the second switch component, and the reinforcing element is a rib. The upper and lower end faces of the first partition 113 are both semi-spherical. This is because both the permeation chamber 11 and the boost chamber 12 need to withstand high-pressure impact during operation, and the semi-spherical surface can reduce local pressure, thereby improving the pressure resistance of the first partition 113. The upper end face of the second partition 122 is semi-spherical for the same reason. The lower end face of the second partition 122 is because the end of the screw assembly at the bottom of the second partition 122 needs to contact the lower end face of the second partition 122 to ensure a certain seal. Therefore, the lower end face of the second partition 122 is a plane, and the thickness of the second partition 122 is also greater than that of the first partition 113.

[0056] The supercritical fluid circulation assembly 2 includes a gas storage tank 21, a delivery pump 22, a circulation tank 23, a gas pressure pump 24, a preheating tank 25, an air intake pump 26 and a circulation pump 27. The gas storage tank 21, the delivery pump 22, the circulation tank 23, the gas pressure pump 24 and the preheating tank 25 are connected in sequence. The preheating tank 25 is connected to the first air inlet 111 of the osmosis chamber 11 through the air intake pump 26, and the first air outlet 112 of the osmosis chamber 11 is connected to the circulation tank 23 through the circulation pump 27.

[0057] The mixing and extrusion chamber 13 is provided with a second air inlet 132 and a second air outlet 133. The second air inlet 132 is connected to the first air outlet 112 via a pipe, and the second air outlet 133 is connected to the circulation pump 27 via a pipe. When the supercritical fluid is stopped from flowing into the osmosis chamber 11, it is necessary to first release the pressure to discharge some carbon dioxide. During the pressure release, the discharged carbon dioxide can be passed into the mixing and extrusion chamber 13 to avoid waste.

[0058] The foaming mold 4 includes an upper mold 42, a lower mold 43 and a forming mold 44. The forming mold 44 is arranged between the upper mold 42 and the lower mold 43. The high-pressure injection head 3 is passed through the upper mold 42 to the forming mold 44. The pressure relief valve 41 is passed through the lower mold 43 to the forming mold 44.

[0059] The foaming mold 4 also includes a temperature control assembly 45, which is positioned between the forming mold 44 and the upper and lower molds 42 and 43. This assembly is used to rapidly cool or heat the foaming material within the forming mold 44. Once the foaming material within the foaming mold 4 has been depressurized, the temperature within the forming mold 44 can be increased by the assembly 45, thereby increasing the foaming rate of the foaming material. After the foaming material has completed foaming, the assembly 45 can be used to rapidly cool the forming mold 44, allowing the supercritical foaming material to solidify and set.

[0060] Example 2

[0061] A method for preparing a supercritical foam material using the apparatus for preparing a supercritical foam material in the first embodiment comprises the following steps:

[0062] Step 1: Introduce carbon dioxide into the kettle 1, high-pressure injection head 3 and foaming mold 4 to clean and exhaust the air, then add TPU particles into the permeation cavity 11 and heat the kettle 1 as a whole to make the temperature of the kettle 1 greater than the critical temperature of the supercritical carbon dioxide fluid and less than the melting temperature of the TPU particles.

[0063] Step 2: The pressurized supercritical carbon dioxide fluid is introduced into the osmotic chamber 11 through the supercritical fluid circulation assembly 2 and circulated for a certain period of time;

[0064] Step 3: Stop the flow of supercritical carbon dioxide fluid into the osmotic chamber 11 and allow the TPU particles in the osmotic chamber 11 to fall into the pressurizing chamber 12. The pressurizing chamber 12 is heated and pressurized separately by the heating element 121 in the pressurizing chamber 12, so that the TPU particles become molten.

[0065] Step 4: The molten TPU is introduced into the mixing and extrusion chamber 13 , and the molten TPU is stirred and extruded into the high-pressure injection head 3 by the screw extrusion assembly 131 in the mixing and extrusion chamber 13 ;

[0066] Step 5. The high-pressure pouring head 3 pours the molten TPU into the foaming mold 4. At the same time, during the pouring process, the pressure in the foaming mold 4 is controlled by the pressure relief valve 41 to be consistent with the pressure of the high-pressure pouring head 3 until the pouring is completed. Then, the pressure in the foaming mold 4 is released to normal pressure through the pressure relief valve 41 to obtain a supercritical foamed TPU material.

[0067] In summary, the present invention separates the infiltration process and extrusion process of the supercritical fluid of the foaming material, which is beneficial to controlling the pressure and temperature of the supercritical fluid during the infiltration process. At the same time, the foaming material needs to be melted in the boosting chamber after the infiltration process, which further improves the uniformity of the distribution of the supercritical fluid inside the foaming material; the pressure in the mixed extrusion chamber is relatively low, and there is no need to pass the supercritical fluid through the screw extrusion assembly to the molten foaming material, so the pressure and damage suffered by the screw extrusion assembly during the extrusion process can be greatly reduced, which is suitable for industrial mass production. The first partition between the infiltration chamber and the boosting chamber plays a role of isolation and protection, and the first switch assembly is a switchable valve that can allow the foaming material to fall from the infiltration chamber into the boosting chamber, and the role of the second partition is the same as that of the first partition. The upper end face and lower end face of the first partition plate are both semi-spherical, this is because no matter whether it is the permeation cavity or the boosting cavity, all need to withstand high pressure impact during operation, and the semi-spherical surface can reduce local pressure, thereby improving the compressive capacity of the first partition plate, and the upper end face of the second partition plate is semi-spherical and it is similarly, and the lower end face of the second partition plate is because the end of the screw assembly at the bottom of the second partition plate needs to contact with the lower end face of the second partition plate, to ensure a certain seal. When stopping to pass supercritical fluid into the permeation cavity, it is necessary to first carry out pressure relief to discharge part of carbon dioxide, and during pressure relief, the carbon dioxide discharged by this part can be passed into the mixed extrusion cavity to avoid waste. After the foaming material pressure relief is completed when being positioned at the foaming mold, the temperature in the forming mold can be increased by the temperature control component, thereby improving the foaming rate of the foaming material. And the foaming material, after foaming is completed, can control the forming mold to cool rapidly by the temperature control component, so that the supercritical foaming material is solidified and shaped.

[0068] After the foaming material is infiltrated by the supercritical fluid, the distribution uniformity of the supercritical fluid in the foaming material can be further improved during the melting process, thereby ensuring that the pore size of the foaming micropores in the final supercritical foaming material can be more uniform, thereby achieving balanced and controllable quality.

[0069] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for preparing supercritical foaming material, characterized in that, It includes a kettle body, a supercritical fluid circulation component, a high-pressure injection head and a foaming mold; The interior of the kettle is provided with an infiltration chamber, a pressurization chamber and a mixing and extrusion chamber in sequence from top to bottom; The permeation chamber is provided with a first air inlet for introducing a supercritical fluid and a first air outlet for discharging the supercritical fluid, the pressurization chamber is provided with a heating element, and the mixing and extrusion chamber is provided with a screw extrusion assembly; The supercritical fluid circulation component is connected to the first air inlet and the first air outlet of the osmosis chamber at the same time, and the supercritical fluid circulation component is used to introduce circulating supercritical fluid into the osmosis chamber; One end of the high-pressure injection head is connected to the mixing and extrusion cavity, and the other end is connected to the foaming mold. The high-pressure injection head is used to inject the molten foaming material in the mixing and extrusion cavity into the foaming mold; The foaming mold is provided with a pressure relief valve which can adjust the internal pressure of the foaming mold.

2. The device for preparing supercritical foaming material according to claim 1, characterized in that A first partition is provided between the osmosis chamber and the boosting chamber, and a first switch assembly is provided on the first partition. A second partition is provided between the boosting chamber and the mixing extrusion chamber, and a second switch assembly is provided on the first partition. The first switch assembly is a switchable valve, and the thickness of the second partition is greater than that of the first partition.

3. The device for preparing supercritical foaming material according to claim 2, characterized in that: The upper end face and the lower end face of the first partition are both semi-spherical, and a first opening for allowing the foaming material to pass through is opened in the middle of the first partition, the first switch component is arranged at the first opening, and a reinforcing element is provided at the connection between the first opening and the first switch component; the upper end face of the second partition is semi-spherical, the lower end face of the second partition is planar, and a second opening for allowing the foaming material to pass through is opened in the middle of the second partition, the second switch component is arranged at the second opening, and a reinforcing element is provided at the connection between the second opening and the second switch component.

4. The device for preparing supercritical foaming material according to claim 1, characterized in that: The supercritical fluid circulation assembly includes a gas storage tank, a delivery pump, a circulation storage tank, a gas pressure pump, a preheating tank, an air intake pump and a circulation pump. The gas storage tank, the delivery pump, the circulation storage tank, the gas pressure pump and the preheating tank are connected in sequence. The preheating tank is connected to the first air inlet of the osmosis chamber through the air intake pump, and the first air outlet of the osmosis chamber is connected to the circulation storage tank through the circulation pump.

5. The device for preparing supercritical foaming material according to claim 4, characterized in that: The mixing extrusion cavity is provided with a second air inlet and a second air outlet. The second air inlet is communicated with the first air outlet through a pipeline, and the second air outlet is communicated with a circulation pump through a pipeline.

6. The device for preparing supercritical foaming material according to claim 1, characterized in that: The foaming mold includes an upper mold, a lower mold and a forming mold. The forming mold is arranged between the upper mold and the lower mold. The high-pressure injection head is inserted from the upper mold into the forming mold. The pressure relief valve is inserted from the lower mold into the forming mold.

7. The device for preparing supercritical foaming material according to claim 1, characterized in that: The foaming mold further includes a temperature control component, which is arranged between the upper mold and the lower mold of the forming mold. The temperature control component is used to quickly cool down or heat the foaming material in the forming mold.

8. A method for preparing a supercritical foam material using the apparatus for preparing a supercritical foam material according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: Passing supercritical fluid into the kettle, high-pressure injection head and foaming mold to clean and expel air, then adding foaming material into the permeation cavity and heating the kettle as a whole to make the temperature of the kettle higher than the critical temperature of the supercritical fluid; Step 2: The pressurized supercritical fluid is introduced into the permeation chamber through the supercritical fluid circulation assembly and circulated for a certain period of time; Step 3: Stop the supercritical fluid from flowing into the osmotic chamber and allow the foaming material in the osmotic chamber to fall into the pressurizing chamber. The pressurizing chamber is heated and pressurized separately by the heating element in the pressurizing chamber to melt the foaming material. Step 4: The molten foaming material is introduced into the mixing and extrusion chamber, and the molten foaming material is stirred and extruded to the high-pressure injection head by the screw extrusion assembly in the mixing and extrusion chamber; Step 5. The high-pressure pouring head pours the molten foaming material into the foaming mold. At the same time, during the pouring process, the pressure in the foaming mold is controlled by the pressure relief valve to keep consistent with the pressure of the high-pressure pouring head until the pouring is completed. Then, the pressure in the foaming mold is released to normal pressure through the pressure relief valve to obtain the supercritical foaming material.

9. The method for preparing a supercritical foam material using the apparatus for preparing a supercritical foam material according to claim 8, wherein: In the step 1, after the kettle body is heated as a whole, the temperature of the kettle body is lower than the melting temperature of the foaming material.

10. The method for preparing a supercritical foam material using the apparatus for preparing a supercritical foam material according to claim 8, characterized in that: The supercritical fluid is a supercritical fluid of carbon dioxide or nitrogen, and the foaming material is a thermoplastic polyurethane elastomer or ethylene-vinyl acetate copolymer.

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