阅读说明：本技术 一种用于制备超临界发泡材料的装置及发泡材料制备方法 (Device for preparing supercritical foaming material and foaming material preparation method ) 是由 吴荣照 林秀欣 袁雄文 文明 于 2021-09-28 设计创作，主要内容包括：本发明涉及一种用于制备超临界发泡材料的装置及发泡材料制备方法,用于制备超临界发泡材料的装置包括釜体、超临界流体循环组件、高压灌注头和发泡模具；所述釜体内部由上至下依次设置有渗透腔、增压腔和混合挤出腔；所述渗透腔内设有用于通入超临界流体的第一进气口和用于排出超临界流体的第一出气口,所述增压腔内设有加热元件,所述混合挤出腔内设有螺杆挤出组件。本发明将对发泡材料的超临界流体的渗透过程何挤出过程分隔开,有利于在渗透过程中对超临界流体的压强和温度进行控制,同时发泡材料在渗透过程后还需在增压腔内熔融,进一步提高了发泡材料内部超临界流体的分布均匀程度。(The invention relates to a device for preparing a supercritical foaming material and a foaming material preparation method, wherein the device for preparing the supercritical foaming material comprises a kettle body, a supercritical fluid circulation component, a high-pressure filling head and a foaming mould; a permeation cavity, a pressurization cavity and a mixing extrusion cavity are sequentially arranged in the kettle body from top to bottom; the permeation cavity is internally provided with a first air inlet for introducing supercritical fluid and a first air outlet for discharging the supercritical fluid, the pressurization cavity is internally provided with a heating element, and the mixing extrusion cavity is internally provided with a screw extrusion assembly. The invention separates the permeation process and the extrusion process of the supercritical fluid of the foaming material, is beneficial to controlling the pressure and the temperature of the supercritical fluid in the permeation process, and simultaneously the foaming material is required to be melted in the pressurizing cavity after the permeation process, thereby further improving the distribution uniformity of the supercritical fluid in the foaming material.)

1. The device for preparing the supercritical foaming material is characterized by comprising a kettle body, a supercritical fluid circulation component, a high-pressure filling head and a foaming mould;

a permeation cavity, a pressurization cavity and a mixing extrusion cavity are sequentially arranged in the kettle body from top to bottom;

a first air inlet for introducing supercritical fluid and a first air outlet for discharging supercritical fluid are arranged in the permeation cavity, a heating element is arranged in the pressurization cavity, and a screw extrusion assembly is arranged in the mixing extrusion cavity;

the supercritical fluid circulation assembly is simultaneously communicated with a first gas inlet and a first gas outlet of the permeation cavity, and is used for introducing a supercritical fluid which circularly flows into the permeation cavity;

one end of the high-pressure filling head is communicated with the mixing extrusion cavity, the other end of the high-pressure filling head is communicated with the foaming mold, and the high-pressure filling head is used for melting foaming materials in the mixing extrusion cavity;

and the foaming mold is provided with a pressure release valve capable of adjusting the internal pressure of the foaming mold.

2. The apparatus for preparing supercritical foaming material according to claim 1, wherein a first partition plate is provided between the permeation chamber and the pressurizing chamber, a first switch assembly is provided on the first partition plate, a second partition plate is provided between the pressurizing chamber and the mixing and extruding chamber, and a second switch assembly is provided on the first partition plate.

3. The apparatus according to claim 2, wherein the upper end surface and the lower end surface of the first partition board are both semi-spherical, a first opening for allowing the foaming material to pass through is formed in the middle of the first partition board, the first switch assembly is arranged at the first opening, and a reinforcing element is arranged at the joint of the first opening and the first switch assembly; the upper end of the second partition board is semicircular, the lower end of the second partition board is planar, a second opening for allowing the foaming material to pass through is formed in the middle of the second partition board, the second switch assembly is arranged at the second opening, and a reinforcing element is arranged at the joint of the second opening and the second switch assembly.

4. The apparatus for preparing supercritical foaming material according to claim 1, wherein the supercritical fluid circulation module comprises a gas storage tank, a delivery pump, a circulation storage tank, a gas pressurization pump, a preheating tank, a gas inlet pump and a circulation pump, the gas storage tank, the delivery pump, the circulation storage tank, the gas pressurization pump and the preheating tank are connected in sequence, the preheating tank is communicated with the first gas inlet of the permeation cavity through the gas inlet pump, and the first gas outlet of the permeation cavity is communicated with the circulation storage tank through the circulation pump.

5. The apparatus according to claim 4, wherein the mixing extrusion chamber is provided with a second gas inlet and a second gas outlet, the second gas inlet is communicated with the first gas outlet through a pipeline, and the second gas outlet is communicated with the circulating pump through a pipeline.

6. The apparatus for preparing supercritical foaming material according to claim 1, wherein the foaming mold comprises an upper mold, a lower mold and a forming mold, the forming mold is disposed between the upper mold and the lower mold, the high pressure filling head is inserted into the forming mold from the upper mold, and the pressure relief valve is inserted into the forming mold from the lower mold.

7. The apparatus according to claim 1, wherein the foaming mold further comprises a temperature control member disposed between the forming mold and the upper and lower molds, the temperature control member being configured to rapidly cool or heat the foaming material within the forming mold.

8. A method for preparing a supercritical foamed material using the apparatus for preparing a supercritical foamed material according to any one of claims 1 to 7, characterized by comprising the steps of:

step one, introducing normal pressure gas of supercritical fluid into the kettle body, the high-pressure filling head and the foaming mould for cleaning and exhausting air, then adding foaming material into the permeation cavity, and heating the kettle body integrally to ensure that the temperature of the kettle body is higher than the critical temperature of the supercritical fluid;

secondly, introducing the pressurized supercritical fluid into the permeation cavity through the supercritical fluid circulation assembly and continuously performing circulation flow for a certain time;

thirdly, stopping introducing the supercritical fluid into the permeation cavity, enabling the foaming material in the permeation cavity to fall into the pressurization cavity, and independently heating and pressurizing the pressurization cavity through a heating element in the pressurization cavity to enable the foaming material to be in a molten state;

step four, introducing the foaming material in the molten state into a mixing extrusion cavity, and stirring and extruding the foaming material in the molten state to a high-pressure filling head through a screw extrusion component in the mixing extrusion cavity;

and step five, the high-pressure filling head fills the foaming material in a molten state into the foaming mold, meanwhile, the pressure in the foaming mold is controlled to be consistent with the pressure of the high-pressure filling head through the pressure relief valve in the filling process until the filling is finished, and then the pressure in the foaming mold is released to the normal pressure through the pressure relief valve to obtain the supercritical foaming material.

9. The method for preparing the supercritical foaming material by using the apparatus for preparing the supercritical foaming material according to claim 8, wherein in the step one, the temperature of the kettle body after the kettle body is heated integrally is lower than the melting temperature of the foaming material.

10. The apparatus for preparing supercritical foamed material according to claim 8, wherein the supercritical fluid is a supercritical fluid of carbon dioxide or nitrogen, and the foamed material is a thermoplastic polyurethane elastomer or an ethylene-vinyl acetate copolymer.

Technical Field

The invention relates to the technical field of foaming materials, in particular to a device for preparing a supercritical foaming material and a foaming material preparation method.

Background

The supercritical foaming is a physical foaming technique, and simultaneously is a microcellular foaming technique, in the processes of injection molding, extrusion and blow molding, firstly, injecting other gases such as carbon dioxide or nitrogen in a supercritical state into a special plasticizing device, fully and uniformly mixing/diffusing the gases and molten raw materials to form single-phase mixed sol, and then guiding the sol to a mold cavity or an extrusion die to ensure that the sol generates large pressure drop, so that the gases are separated out to form a large number of bubble nuclei; in the subsequent cooling and forming process, bubble nuclei in the sol continuously grow and are formed, and finally, the micropore foaming plastic product is obtained.

Taking TPU (thermoplastic polyurethane elastomer) foaming particles as an example, the application of the TPU foaming particles in the fields of soles and the like is a certain development trend and has great market value. The shoe material field is only a knock-out brick applied by the material, and the material can be used in the fields of spaceflight, traffic, buffering, sports, medical treatment and the like after being mature and applied. At present, in the process of preparing the TPU foaming material, the continuous extrusion foaming efficiency is high, the TPU foaming material is suitable for industrial mass production, but the supercritical fluid needs to be released through a screw to achieve a good permeation effect, so that the high pressure required for maintaining the supercritical fluid state can easily cause great damage to the screw, and the requirement on the strength of the screw is high. In addition, in the continuous extrusion process, the foaming material is always kept in a molten state, so that technological parameters such as the pressure, the temperature, the pressure release rate and the like of supercritical carbon dioxide are difficult to adjust and control in the foaming process, and the quality of a finished product of the foaming material is difficult to balance.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a device for preparing a supercritical foaming material and a foaming material preparation method, which are suitable for industrial mass production, reduce the damage of high pressure to extrusion equipment and are convenient for regulating and controlling process parameters in a foaming process.

In order to solve the technical problems, the invention adopts a technical scheme that: an apparatus for preparing supercritical foaming material, comprising a kettle body, a supercritical fluid circulation component, a high-pressure filling head and a foaming mould;

a permeation cavity, a pressurization cavity and a mixing extrusion cavity are sequentially arranged in the kettle body from top to bottom;

a first air inlet for introducing supercritical fluid and a first air outlet for discharging supercritical fluid are arranged in the permeation cavity, a heating element is arranged in the pressurization cavity, and a screw extrusion assembly is arranged in the mixing extrusion cavity;

the supercritical fluid circulation assembly is simultaneously communicated with a first gas inlet and a first gas outlet of the permeation cavity, and is used for introducing a supercritical fluid which circularly flows into the permeation cavity;

one end of the high-pressure filling head is communicated with the mixing extrusion cavity, the other end of the high-pressure filling head is communicated with the foaming mold, and the high-pressure filling head is used for melting foaming materials in the mixing extrusion cavity;

and the foaming mold is provided with a pressure release valve capable of adjusting the internal pressure of the foaming mold.

The device comprises a permeation cavity, a pressurization cavity, a mixing extrusion cavity, a first partition plate, a second partition plate and a second switch assembly, wherein the first partition plate is arranged between the permeation cavity and the pressurization cavity, the first switch assembly is arranged on the first partition plate, the second partition plate is arranged between the pressurization cavity and the mixing extrusion cavity, and the second switch assembly is arranged on the first partition plate.

The upper end surface and the lower end surface of the first partition board are both in a semi-spherical shape, a first opening for enabling the foaming material to pass through is formed in the middle of the first partition board, the first switch assembly is arranged at the first opening, and a reinforcing element is arranged at the joint of the first opening and the first switch assembly; the upper end of the second partition board is semicircular, the lower end of the second partition board is planar, a second opening for allowing the foaming material to pass through is formed in the middle of the second partition board, the second switch assembly is arranged at the second opening, and a reinforcing element is arranged at the joint of the second opening and the second switch assembly.

The supercritical fluid circulation assembly comprises a gas storage tank, a delivery pump, a circulation storage tank, a gas pressurizing pump, a preheating tank, a gas inlet pump and a circulating pump, wherein the gas storage tank, the delivery pump, the circulation storage tank, the gas pressurizing pump and the preheating tank are sequentially connected, the preheating tank is communicated with a first gas inlet of the permeation cavity through the gas inlet pump, and a first gas outlet of the permeation cavity is communicated with the circulation storage tank through the circulating pump.

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 the circulating pump through a pipeline.

The foaming mold comprises 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 filling head penetrates through the upper mold and the forming mold, and the pressure release valve penetrates through the lower mold and the forming mold.

The foaming mould further comprises a temperature control assembly, the temperature control assembly is arranged between the forming mould and the upper mould and between the forming mould and the lower mould, and the temperature control assembly is used for rapidly cooling or heating the foaming material in the forming mould.

The invention has the beneficial effects that: the permeation process and the extrusion process of the supercritical fluid of the foaming material are separated, so that the pressure and the temperature of the supercritical fluid can be controlled in the permeation process, and meanwhile, the foaming material needs to be melted in a pressurizing cavity after the permeation process, so that the distribution uniformity of the supercritical fluid in the foaming material is further improved; the pressure in the mixing extrusion cavity is relatively low, and the supercritical fluid is not needed to be introduced into the foaming material in a molten state through the screw extrusion assembly, so that the pressure and damage to the screw extrusion assembly in the extrusion process can be greatly reduced, and the method is suitable for industrial mass production.

The other technical scheme adopted by the invention is as follows: a method for preparing a supercritical foaming material by using the above apparatus for preparing a supercritical foaming material, comprising the steps of:

step one, introducing normal pressure gas of supercritical fluid into the kettle body, the high-pressure filling head and the foaming mould for cleaning and exhausting air, then adding foaming material into the permeation cavity, and heating the kettle body integrally to ensure that the temperature of the kettle body is higher than the critical temperature of the supercritical fluid;

secondly, introducing the pressurized supercritical fluid into the permeation cavity through the supercritical fluid circulation assembly and continuously performing circulation flow for a certain time;

thirdly, stopping introducing the supercritical fluid into the permeation cavity, enabling the foaming material in the permeation cavity to fall into the pressurization cavity, and independently heating and pressurizing the pressurization cavity through a heating element in the pressurization cavity to enable the foaming material to be in a molten state;

step four, introducing the foaming material in the molten state into a mixing extrusion cavity, and stirring and extruding the foaming material in the molten state to a high-pressure filling head through a screw extrusion component in the mixing extrusion cavity;

and step five, the high-pressure filling head fills the foaming material in a molten state into the foaming mold, meanwhile, the pressure in the foaming mold is controlled to be consistent with the pressure of the high-pressure filling head through the pressure relief valve in the filling process until the filling is finished, and then the pressure in the foaming mold is released to the normal pressure through the pressure relief valve to obtain the supercritical foaming material.

In the first step, the temperature of the kettle body is lower than the melting temperature of the foaming material after the kettle body is integrally heated.

The foaming material is a thermoplastic polyurethane elastomer or an ethylene-vinyl acetate copolymer.

The invention has the beneficial effects that: after the foaming material is permeated by the supercritical fluid, the distribution uniformity of the supercritical fluid in the foaming material can be further improved in the melting process, and the pore diameter of the foaming micropores in the finally obtained supercritical foaming material can be more even, so that the balance and controllability of the quality are realized.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for preparing a supercritical foamed material according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of the interior of the autoclave body in the embodiment of the present invention;

description of reference numerals:

1. a kettle body; 11. a permeate chamber; 111. a first air inlet; 112. a first air outlet; 113. a first separator; 12. a pressurizing cavity; 121. a heating element; 122. a second separator; 13. a mixing extrusion chamber; 131. a screw extrusion assembly; 132. a second air inlet; 133. a second gas outlet 2, a supercritical fluid circulation component; 21. a gas storage tank; 22. a delivery pump; 23. circulating the storage tank; 24. a gas pressure pump; 25. a preheating tank; 26. an intake pump; 27. a circulation pump; 3. a high pressure filling head; 4. a foaming mold; 41. a pressure relief valve; 42. an upper die; 43. a lower die; 44. forming a mould; 45. a temperature control component.

Detailed Description

In order to explain technical contents, achieved objects, and effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.

Referring to fig. 1 to 2, an apparatus for preparing a supercritical foaming material according to the present invention includes a kettle 1, a supercritical fluid circulation module 2, a high-pressure filling head 3, and a foaming mold 4;

the inside of the kettle body 1 is sequentially provided with a permeation cavity 11, a pressurization cavity 12 and a mixing extrusion cavity 13 from top to bottom;

a first air inlet 111 for introducing supercritical fluid and a first air outlet 112 for discharging supercritical fluid are arranged in the permeation cavity 11, a heating element 121 is arranged in the pressurization cavity 12, and a screw extrusion assembly 131 is arranged in the mixing extrusion cavity 13;

the supercritical fluid circulation assembly 2 is simultaneously communicated with a first gas inlet 111 and a first gas outlet 112 of the permeation cavity 11, and the supercritical fluid circulation assembly 2 is used for introducing a supercritical fluid which circularly flows into the permeation cavity 11;

one end of the high-pressure pouring head 3 is communicated with the mixing extrusion cavity 13, the other end of the high-pressure pouring head is communicated with the foaming mould 4, and the high-pressure pouring head 3 is used for melting foaming materials in the mixing extrusion cavity 13;

and a pressure release valve 41 capable of adjusting the internal pressure of the foaming mold 4 is arranged on the foaming mold 4.

When the device is used, the gas with the same normal temperature and normal pressure as the supercritical fluid for subsequent foaming, such as carbon dioxide or nitrogen, needs to be introduced into the kettle body 1, the high-pressure filling head 3 and the foaming mould 4 to clean and discharge air so as to ensure that the foaming process is not interfered by the air, then the foaming material, such as TPU particles or EVA particles, is put into the permeation cavity 11 of the kettle body 1, the permeation cavity 11 and the pressurization cavity 12 are kept relatively closed, and then the kettle body 1 is wholly heated so that the temperature of the kettle body 1 is higher than the critical temperature of the supercritical fluid, so that the supercritical state can be kept when the supercritical fluid flows in the kettle body 1; then, the pressurized supercritical fluid is introduced into the permeation cavity 11 through the supercritical fluid circulation component 2 and continuously flows in a circulation manner for a certain time, in the process, the supercritical fluid needs to be maintained in a supercritical state and is subjected to pressure maintaining permeation for a certain time, the supercritical fluid gradually permeates into the foaming material along with the circulation flow process, and a large amount of saturated supercritical fluid is in the foaming material; after a certain period of permeation, the introduction of the supercritical fluid into the permeation cavity 11 is stopped, meanwhile, the foaming material in the permeation cavity 11 falls into the pressurization cavity 12, then, the pressurization cavity 12 is independently heated and pressurized by the heating element 121 in the pressurization cavity 12, during the heating and pressurization process of the pressurization cavity 12, the state of the supercritical fluid is not changed, meanwhile, the pressurization can also reduce the melting temperature of the foaming material, so that the foaming material can reach the melting state more quickly, and when the foaming material is melted, the supercritical fluid can further flow in the melted foaming material, so that a more uniform diffusion effect is achieved; when the foaming material is completely melted, the foaming material in a molten state is introduced into the mixing extrusion cavity 13, at this time, because the pressure in the mixing extrusion cavity 13 is reduced, and the supercritical fluid is not required to be introduced into the foaming material in a molten state through the screw extrusion component 131, the pressure and damage to the screw extrusion component 131 in the extrusion process can be greatly reduced, and the screw extrusion component 131 can also relatively and rapidly operate to ensure that the foaming material can be extruded into the high-pressure filling head 3 before being cooled; and finally, the high-pressure pouring head 3 pours the foaming material in a molten state into the foaming mold 4, meanwhile, the pressure in the foaming mold 4 is controlled to be consistent with the pressure of the high-pressure pouring head 3 through the pressure release valve 41 in the pouring process until the pouring is finished, then, the pressure in the foaming mold 4 is quickly released to normal pressure through the pressure release valve 41, in the pressure release process, under a high pressure difference, the supercritical fluid in the foaming material is quickly expanded and forms a large number of bubble nuclei, and the bubble nuclei expand and grow due to the existence of a large pressure difference, and finally, the supercritical foaming material is obtained.

A method for preparing a supercritical foaming material by using the above apparatus for preparing a supercritical foaming material, comprising the steps of:

step one, introducing normal pressure gas of a supercritical fluid into the kettle body 1, the high-pressure filling head 3 and the foaming mould 4 for cleaning and exhausting air, then adding a foaming material into the permeation cavity 11, and heating the whole kettle body 1 to ensure that the temperature of the kettle body 1 is higher than the critical temperature of the supercritical fluid;

secondly, the pressurized supercritical fluid is introduced into the permeation cavity 11 through the supercritical fluid circulation component 2 and continuously flows in a circulating manner for a certain time;

thirdly, stopping introducing the supercritical fluid into the permeation cavity 11, enabling the foaming material in the permeation cavity 11 to fall into the pressurization cavity 12, and independently heating and pressurizing the pressurization cavity 12 through the heating element 121 in the pressurization cavity 12 to enable the foaming material to be in a molten state;

step four, introducing the foaming material in the molten state into the mixing extrusion cavity 13, and stirring and extruding the foaming material in the molten state to the high-pressure filling head 3 through the screw extrusion component 131 in the mixing extrusion cavity 13;

and step five, the high-pressure filling head 3 fills the foaming material in a molten state into the foaming mold 4, meanwhile, the pressure in the foaming mold 4 is controlled to be consistent with the pressure of the high-pressure filling head 3 through the pressure relief valve 41 in the filling process until the filling is finished, and then the pressure in the foaming mold 4 is released to the normal pressure through the pressure relief valve 41 to obtain the supercritical foaming material.

In the first step, the temperature of the kettle body 1 is lower than the melting temperature of the foaming material after the kettle body 1 is integrally heated.

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

Example one

As shown in fig. 1 and 2, an apparatus for preparing a supercritical foaming material includes a tank 1, a supercritical fluid circulation module 2, a high-pressure filling head 3, and a foaming mold 4;

the inside of the kettle body 1 is sequentially provided with a permeation cavity 11, a pressurization cavity 12 and a mixing extrusion cavity 13 from top to bottom;

a first air inlet 111 for introducing supercritical fluid and a first air outlet 112 for discharging supercritical fluid are arranged in the permeation cavity 11, a heating rod is arranged in the pressurization cavity 12, a screw extrusion assembly 131 is arranged in the mixing extrusion cavity 13, and the screw extrusion assembly 131 comprises a main shaft, blades arranged around the main shaft and a motor for driving the screw;

the supercritical fluid circulation assembly 2 is simultaneously communicated with a first gas inlet 111 and a first gas outlet 112 of the permeation cavity 11, and the supercritical fluid circulation assembly 2 is used for introducing a supercritical fluid which circularly flows into the permeation cavity 11;

one end of the high-pressure pouring head 3 is communicated with the mixing extrusion cavity 13, the other end of the high-pressure pouring head is communicated with the foaming mould 4, and the high-pressure pouring head 3 is used for melting foaming materials in the mixing extrusion cavity 13;

and a pressure release valve 41 capable of adjusting the internal pressure of the foaming mold 4 is arranged on the foaming mold 4.

A first partition plate 113 is arranged between the permeation cavity 11 and the pressurization cavity 12, a first switch component is arranged on the first partition plate 113, a second partition plate 122 is arranged between the pressurization cavity 12 and the mixing extrusion cavity 13, and a second switch component is arranged on the first partition plate 113. The first partition 113 between the permeate chamber 11 and the pressure increasing chamber 12 serves as an isolation and protection, and the first switch assembly is a switchable valve which allows the foamed material to fall from the permeate chamber 11 into the pressure increasing chamber 12, while the second partition 122 serves as the same as the first partition 113.

The upper end surface and the lower end surface of the first partition board 113 are both in a semi-spherical shape, a first opening for allowing the foaming material to pass through is formed in the middle of the first partition board 113, the first switch assembly is arranged at the first opening, a reinforcing element is arranged at the joint of the first opening and the first switch assembly, and the reinforcing element is a rib; the upper end surface of the second partition plate 122 is semi-spherical, the lower end surface of the second partition plate 122 is planar, a second opening for allowing the foaming material to pass through is formed in the middle of the second partition plate 122, the second switch assembly is arranged at the second opening, and a reinforcing element is arranged at the joint of the second opening and the second switch assembly and is a rib. The upper end surface and the lower end surface of the first separation plate 113 are both in a semi-spherical shape, and both the permeation chamber 11 and the pressurization chamber 12 need to bear high pressure impact in the working process, and the semi-spherical surface can reduce local pressure, so that the pressure resistance of the first separation plate 113 is improved, the upper end surface of the second separation plate 122 is in a semi-spherical shape, and the lower end surface of the second separation plate 122 is in contact with the lower end surface of the second separation plate 122 due to the end part of the screw assembly at the bottom of the second separation plate 122, so that certain sealing is ensured, the lower end surface of the second separation plate 122 is a plane, and meanwhile, the thickness of the second separation plate 122 is also larger than that of the first separation plate 113.

The supercritical fluid circulation assembly 2 comprises a gas storage tank 21, a delivery pump 22, a circulation storage tank 23, a gas pressurization pump 24, a preheating tank 25, a gas inlet pump 26 and a circulation pump 27, wherein the gas storage tank 21, the delivery pump 22, the circulation storage tank 23, the gas pressurization pump 24 and the preheating tank 25 are sequentially connected, the preheating tank 25 is communicated with a first gas inlet 111 of the permeation cavity 11 through the gas inlet pump 26, and a first gas outlet 112 of the permeation cavity 11 is communicated with the circulation storage tank 23 through the circulation pump 27.

And a second air inlet 132 and a second air outlet 133 are arranged on the mixing extrusion cavity 13, the second air inlet 132 is communicated with the first air outlet 112 through a pipeline, and the second air outlet 133 is communicated with the circulating pump 27 through a pipeline. When the supercritical fluid is stopped being introduced into the permeation cavity 11, the supercritical fluid needs to be firstly decompressed to discharge part of the carbon dioxide, and the part of the discharged carbon dioxide can be introduced into the mixing extrusion cavity 13 during decompression, so that waste is avoided.

The foaming mold 4 comprises 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 filling head 3 is arranged in the forming mold 44 in a penetrating manner from the upper mold 42, and the pressure relief valve 41 is arranged in the forming mold 44 in a penetrating manner from the lower mold 43.

The foaming mold 4 further comprises a temperature control assembly 45, the temperature control assembly 45 is arranged between the forming mold 44 and the upper mold 42 and the lower mold 43, and the temperature control assembly 45 is used for rapidly cooling or heating the foaming material in the forming mold 44. After the foaming material in the foaming mold 4 is completely decompressed, the temperature in the forming mold 44 can be increased by the temperature control component 45, so that the foaming rate of the foaming material is increased. After the foaming material is foamed, the temperature control component 45 can control the forming die 44 to rapidly cool, so that the supercritical foaming material is solidified and shaped.

Example two

A method for preparing a supercritical foamed material by using the apparatus for preparing a supercritical foamed material according to the first embodiment, comprising the steps of:

step one, introducing carbon dioxide into the kettle body 1, the high-pressure filling head 3 and the foaming mould 4 for cleaning and exhausting air, then adding TPU particles into the permeation cavity 11, and heating the kettle body 1 integrally to ensure that the temperature of the kettle body 1 is higher than the critical temperature of supercritical carbon dioxide fluid and lower than the melting temperature of the TPU particles

Secondly, introducing the pressurized supercritical carbon dioxide fluid into the permeation cavity 11 through the supercritical fluid circulation component 2 and continuously performing circulation flow for a certain time;

step three, stopping introducing the supercritical carbon dioxide fluid into the infiltration cavity 11, enabling the TPU particles in the infiltration cavity 11 to fall into the pressurization cavity 12, and independently heating and pressurizing the pressurization cavity 12 through the heating element 121 in the pressurization cavity 12 to enable the TPU particles to be in a molten state;

step four, introducing the TPU in a molten state into the mixing extrusion cavity 13, and stirring and extruding the TPU in the molten state to the high-pressure filling head 3 through the screw extrusion component 131 in the mixing extrusion cavity 13;

and step five, the high-pressure pouring head 3 pours the molten TPU into the foaming mold 4, meanwhile, the pressure in the foaming mold 4 is controlled to be consistent with the pressure of the high-pressure pouring head 3 through the pressure relief valve 41 in the pouring process until the pouring is finished, and then the pressure in the foaming mold 4 is released to the normal pressure through the pressure relief valve 41 to obtain the supercritical foaming TPU material.

In conclusion, the invention separates the permeation process and the extrusion process of the supercritical fluid of the foaming material, is beneficial to controlling the pressure and the temperature of the supercritical fluid in the permeation process, and simultaneously the foaming material is required to be melted in the pressurizing cavity after the permeation process, thereby further improving the distribution uniformity of the supercritical fluid in the foaming material; the pressure in the mixing extrusion cavity is relatively low, and the supercritical fluid is not needed to be introduced into the foaming material in a molten state through the screw extrusion assembly, so that the pressure and damage to the screw extrusion assembly in the extrusion process can be greatly reduced, and the method is suitable for industrial mass production. The first baffle between infiltration chamber and the pressure boost chamber has played the effect of keeping apart and protection, and but first switch module is the valve of switch, can make expanded material fall into the pressure boost intracavity by the infiltration chamber, and the effect of second baffle is the same with first baffle. The upper end face and the lower end face of the first partition plate are both in a semi-sphere shape, high-pressure impact needs to be borne in the working process no matter in a permeation cavity or a pressurization cavity, the semi-sphere surface can reduce local pressure, and therefore the pressure resistance of the first partition plate is improved. When the supercritical fluid is stopped to be introduced into the permeation cavity, the permeation cavity needs to be firstly decompressed to discharge part of carbon dioxide, and the part of the discharged carbon dioxide can be introduced into the mixing extrusion cavity during decompression, so that waste is avoided. After the foaming material in the foaming mold is decompressed, the temperature in the forming mold can be increased through the temperature control assembly, so that the foaming rate of the foaming material is increased. After the foaming material is foamed, the temperature control assembly can control the forming die to rapidly cool so as to solidify and shape the supercritical foaming material.

After the foaming material is permeated by the supercritical fluid, the distribution uniformity of the supercritical fluid in the foaming material can be further improved in the melting process, and the pore diameter of the foaming micropores in the finally obtained supercritical foaming material can be more even, so that the balance and controllability of the quality are realized.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.