An apparatus for continuously foaming and forming a microporous foam particulate material under constant temperature and pressure and a preparation method thereof

Abstract

The present invention discloses a constant-temperature and constant-pressure continuous foaming and forming device for microcellular foam particle materials, which comprises a frame, a constant-pressure feeding system, a constant-temperature and constant-pressure gas and liquid supply system, and a constant-temperature and constant-pressure foaming system installed on the frame. A pressure balance pipeline is arranged between the constant-pressure feeding system and the constant-temperature and constant-pressure foaming system. A pressure balance valve is installed on the constant-pressure feeding system. The constant-pressure feeding system provides constant-pressure automatic feeding of granular materials. The constant-temperature and constant-pressure gas and liquid supply system provides constant-temperature and constant-pressure gas and release agent. Furthermore, the constant-temperature and constant-pressure foaming system produces microcellular foam particle materials by stirring granular materials, gas and release agent. The pressure balance pipeline ensures that the air pressures of the constant-pressure feeding system and the constant-temperature and constant-pressure foaming system are equal. The constant-pressure feeding system releases excessive internal pressure through the pressure balance valve. It has the advantages of compact structure, uniform temperature, constant pressure, stable foaming and forming quality, capable of continuous foaming and forming, and high production efficiency.

Description

Technical Field

[0001] The present invention relates to a forming device for microcellular foam particulate materials and a preparation method thereof, and particularly to a constant-temperature and constant-pressure continuous foaming forming device for microcellular foam particulate materials and a preparation method thereof. Background Art

[0002] Microcellular foam particulate materials are a new type of foaming material with a micron-level cell diameter. The cells are small and dense, and evenly distributed. The polymer foamed beads have characteristics such as light weight, buffering, high toughness, and easy molding. Compared with traditional foam plastics with a cell size in the millimeter range, microcellular foam materials have more excellent mechanical properties, dimensional stability, thermal stability, dielectric properties, etc., and have special application values in the fields of automobiles, airplanes, and various transportation equipment. In addition, it can also be used in food packaging, biomedicine, building materials, household appliances, information engineering, sports equipment, etc. The traditional bead foaming technology often uses the intermittent pressure release method in a high-pressure autoclave to prepare, or the continuous melt extrusion foaming molding method to prepare.

[0003] In the high-pressure autoclave foaming process, usually a heat transfer medium (mainly water) is added and the reaction time is extended to achieve the effect of uniform temperature. Then, the particles are ejected through rapid pressure relief at the bottom of the pressure vessel to obtain foamed beads to realize the nucleation and growth of the cells. This method has a simple preparation process and is widely used, but there are serious quality problems. Since the pressure in the foaming tank is fixed and limited, and the pressure relief process requires a certain time, the pressure drops suffered by the ejected particles are different, ultimately resulting in great differences in the foaming degree, size, and performance of the foamed beads. Moreover, the material heating time is long, the energy consumption is high, the post-treatment separation and drying process is increased, and the production efficiency is low.

[0004] The common processing process of continuous microcellular foam materials is as follows: First, the polymer raw material is added to a foaming extruder. After the polymer material is melted, a supercritical fluid is injected into the polymer melt through the injection port of the barrel. Under the action of shear mixing in the barrel, a homogeneous polymer-gas system is formed. Then, it is cooled to the foaming temperature, conveyed to the foaming head for extrusion foaming, and pelletized and cooled for shaping, that is, microcellular foam particles are obtained. However, this forming method has defects such as unstable pressure, uneven mixing of the supercritical fluid, low foaming forming quality, unstable magnification, slow shaping and cooling speed, and low output.

[0005] In recent years, a semi-continuous foaming process technology has been developed, which belongs to an intermittent method for producing polymer microcellular foamed beads.

[0006] Publication No. of the application: CN 108410061 A. This invention discloses a thermoplastic polymer foamed bead and a preparation method thereof. The preparation method includes: 1) extruding and granulating a foaming-grade thermoplastic polymer resin composition to make foaming particles; 2) placing the foaming particles in a constant-temperature high-pressure reactor A, filling with a supercritical fluid for penetration and swelling until reaching diffusion equilibrium to form a polymer-supercritical fluid homogeneous system; 3) using a magnetic-sealed stirring device to transfer the balanced foaming particles to a high-pressure reactor B at a constant pressure; 4) finally discharging the materials in the high-pressure reactor B through a quick-opening ball valve under pressure, and the polymer particles foam and expand to obtain foamed beads.

[0007] Publication No. of the application: CN 108394060 A. This invention relates to a semi-continuous bead foaming device, which includes a first high-pressure reactor, a screw conveying device, a second high-pressure reactor and a pressure compensation tank. A first stirring device is arranged in the first high-pressure reactor. The screw conveying device is driven to work by a magnetic stirring device. The screw conveying device connects the first high-pressure reactor and the second high-pressure reactor. The second high-pressure reactor is communicated with the pressure compensation tank, and the second high-pressure reactor is communicated with the first high-pressure reactor through a pressure balance pipe.

[0008] Granted Publication No.: CN 207210308 U discloses a polymer supercritical carbon dioxide foamed bead production line, which includes a gas supply group, a heating group and a production group. The gas supply group includes a carbon dioxide storage tank, a heat exchange device and a carbon dioxide buffer tank connected in sequence. The heating group includes heating rods and a heat-conducting oil pump. The heating rods heat the heating oil in the heat exchange device, and the heat-conducting oil pump transports the heating oil to the gas supply group and the production group. The production group includes a stirring reaction kettle, a high-pressure nozzle and a bead collection tank. The bottom outlet of the right cylinder of the carbon dioxide buffer tank is connected to the left inlet of the bottom head of the stirring reaction kettle. The bottom outlet of the stirring reaction kettle sprays and foams the polymer beads through the high-pressure nozzle, and the foamed beads are collected in the bead collection tank.

[0009] The above-mentioned technology is to put polymer particles into the reaction tank in batches, pressurize with carbon dioxide, heat and stir with a heating device, and then spray and foam the polymer beads through a high-pressure nozzle at the bottom outlet of the stirring reaction kettle.

[0010] The above-mentioned technology belongs to a semi-continuous method for producing polymer microcellular foamed beads, which cannot achieve continuous feeding and continuous foaming production, and has the defects of unstable production quality and low production efficiency. Summary of the Invention

[0011] The object of the present invention is to overcome the above-mentioned defects in the prior art, and to provide an apparatus and a preparation method thereof which can achieve uniform temperature, constant pressure, easily obtain uniform expanded bead products, have stable foaming molding quality, high production efficiency, and can continuously supply polymer particle materials and supercritical mixed fluids for continuous foaming molding at constant temperature and pressure.

[0012] To achieve the above object, the present invention provides a constant temperature and constant pressure continuous foaming molding apparatus for microcellular foam particle materials, which comprises a frame, a constant pressure feeding system installed on one side of the frame for automatically feeding particle materials at constant pressure, a constant temperature and constant pressure gas and liquid supply system installed on one side of the constant pressure feeding system, and a constant temperature and constant pressure foaming system installed below the constant pressure feeding system. A pressure balance pipeline is provided between the constant pressure feeding system and the constant temperature and constant pressure foaming system, and a pressure balance valve is installed on the constant pressure feeding system.

[0013] Preferably, the constant pressure feeding system includes a polymer particle storage tank installed on the frame, a pressure feeder communicated with the polymer particle storage tank, a constant pressure storage tank communicated with the pressure feeder, a feeder and a second control valve installed between the polymer particle storage tank and the pressure feeder, a booster pump and a pressure relief valve respectively installed on one side of the pressure feeder and communicated with the pressure feeder, a first control valve installed between the booster pump and the pressure feeder, a third control valve installed between the pressure feeder and the constant pressure storage tank, and a metering feeder installed below the constant pressure storage tank. The pressure balance pipeline and the pressure balance valve are respectively communicated with the constant pressure storage tank.

[0014] Preferably, the constant temperature and constant pressure gas and liquid supply system includes a liquid nitrogen storage tank, a liquid carbon dioxide storage tank and an isolation agent liquid storage tank respectively installed on one side of the rack, a nitrogen constant pressure and constant temperature storage tank connected to the liquid nitrogen storage tank, a carbon dioxide constant pressure and constant temperature storage tank connected to the liquid carbon dioxide storage tank, a first high-pressure pump installed between the liquid carbon dioxide storage tank and the carbon dioxide constant pressure and constant temperature storage tank, a first gas heater installed between the first high-pressure pump and the carbon dioxide constant pressure and constant temperature storage tank, a second high-pressure pump installed between the liquid nitrogen storage tank and the nitrogen constant pressure and constant temperature storage tank, and a second gas heater installed between the second high-pressure pump and the nitrogen constant pressure and constant temperature storage tank. The gases in the nitrogen constant-pressure and constant-temperature storage tank and the carbon dioxide constant-pressure and constant-temperature storage tank merge and enter the constant-temperature and constant-pressure foaming system. A third gas heater is installed at the gas confluence of the nitrogen constant-pressure and constant-temperature storage tank and the carbon dioxide constant-pressure and constant-temperature storage tank. Flow control valves are installed between the third gas heater and the nitrogen constant-pressure and constant-temperature storage tank and between the third gas heater and the carbon dioxide constant-pressure and constant-temperature storage tank. The isolation agent liquid storage tank is connected to the constant-temperature and constant-pressure foaming system. A liquid heater is installed between the isolation agent liquid storage tank and the constant-temperature and constant-pressure foaming system. A liquid delivery high-pressure pump is installed between the liquid heater and the isolation agent liquid storage tank.

[0015] Preferably, the constant temperature and constant pressure foaming system includes a constant temperature and constant pressure stirring continuous propeller installed on a frame, a driving motor installed on one side of the constant temperature and constant pressure stirring continuous propeller and fixedly connected to the frame, a propulsion propeller installed inside the constant temperature and constant pressure stirring continuous propeller and transmission connected to the driving motor, a foam particle storage tank installed at the discharge port of the constant temperature and constant pressure stirring continuous propeller and connected to the constant temperature and constant pressure stirring continuous propeller, and the constant pressure feeding system, constant temperature and constant pressure air and liquid supply system and pressure balance pipeline are respectively connected to the constant temperature and constant pressure stirring continuous propeller.

[0016] Preferably, an adjustable conical foaming particle nozzle connected to the constant temperature and pressure stirring continuous propeller is installed at the discharge port of the constant temperature and pressure stirring continuous propeller.

[0017] Preferably, the constant temperature and constant pressure stirring continuous propeller is internally provided with screw pins and dispersion pins arranged in an array.

[0018] Compared with the prior art, the constant temperature and constant pressure continuous foaming molding device for microporous foam particle materials provided by the present invention has the following beneficial effects:

[0019] The constant-pressure feeding system provides constant-pressure automatic feeding of granular materials for the constant-temperature and constant-pressure foaming system. At the same time, the constant-temperature and constant-pressure gas and liquid supply system provides constant-temperature and constant-pressure gas and release agent for the constant-temperature and constant-pressure foaming system. Furthermore, the constant-temperature and constant-pressure foaming system produces microcellular foam granular materials by stirring the granular materials, gas and release agent. The constant-pressure feeding system is connected to the constant-temperature and constant-pressure foaming system through a pressure balance pipeline to ensure that the air pressures of the constant-pressure feeding system and the constant-temperature and constant-pressure foaming system are equal during the whole production process. Among them, the constant-pressure feeding system releases the excessive internal pressure through a pressure balance valve to ensure the continuous foaming and forming of the microcellular foam granular materials at constant temperature and constant pressure. The present invention has the advantages of compact structure, uniform temperature, constant pressure, continuous production, stable foaming and forming quality, and high production efficiency.

[0020] The present invention also provides a preparation method for the continuous foaming of microcellular foam granular materials at constant temperature and constant pressure, including the following preparation steps:

[0021] S1. Transfer the polymer particles in the polymer particle storage tank to the pressure feeder through a feeder, and the pressure feeder quantitatively weighs the polymer particles;

[0022] S2. When the polymer particles in the pressure feeder in step S1 reach a certain mass, transfer the polymer particles in the pressure feeder to the constant-pressure storage tank by pressurization. When there is no material in the pressure feeder, the inside of the pressure feeder returns to normal pressure through a connecting pressure relief valve. The internal gas pressure of the constant-pressure storage tank is 3 - 30 MPa, and the temperature is 60 - 350 °C;

[0023] S3. Transfer the polymer particles in the constant-pressure storage tank in step S2 to the constant-temperature and constant-pressure stirring continuous pusher through a quantitative feeder. At the same time, constant-temperature and constant-pressure nitrogen, carbon dioxide and release agent are simultaneously transported into the constant-temperature and constant-pressure stirring continuous pusher through flow control valves; the gas pressures of the constant-temperature and constant-pressure nitrogen and carbon dioxide storage tanks are 3 - 30 MPa, and the temperature is 60 - 350 °C; the liquid pressure of the release agent is 3 - 30 MPa, and the temperature is 60 - 350 °C; the rotation speed of the constant-temperature and constant-pressure stirring continuous pusher is 10 - 1000 revolutions per minute;

[0024] S4. Stir the polymer particles, nitrogen, carbon dioxide and release agent inside the constant-temperature and constant-pressure stirring continuous pusher in step S3 by driving the propulsion screw with a motor. The formed microcellular foam granular materials are transported forward under the drive of the propulsion screw of the constant-temperature and constant-pressure stirring continuous pusher. The granular materials are constantly and pressure-stably ejected from the adjustable conical foaming granular nozzle, and the pressure relief rate is 1 - 1000 MPa / second. Finally, microcellular foamed granular products are formed and collected at the discharge port to obtain a density of 0.6 - 0.01 g / cm 3Microcellular foamed beads. During the whole process, a pressure balance pipeline is connected between the constant temperature and pressure stirring continuous propeller and the constant pressure storage tank described in step S3, and a pressure balance valve is arranged on the constant pressure storage tank.

[0025] Preferably, in step S3, nitrogen is formed by heating liquid nitrogen, and carbon dioxide is formed by heating liquid carbon dioxide.

[0026] Preferably, in step S4, at the discharge port of the constant temperature and pressure stirring continuous propeller, a system's constant pressure drop and pressure relief rate are adjusted by connecting an adjustable conical foamed particle nozzle to ensure that the system continuously sprays out microcellular foamed beads at a constant pressure, obtaining microcellular foamed bead products with a density of 0.6 - 0.01 g / cm 3 of microcellular foamed bead products.

[0027] Preferably, inside the constant temperature and pressure stirring continuous propeller in step S4, screw pins and dispersion pins are arranged to mix and disperse the granular materials to ensure temperature uniformity and prevent the granular materials from sticking together.

[0028] Compared with the prior art, the beneficial effects of a preparation method of a microcellular foam particle material provided by the present invention are as follows:

[0029] This method can continuously supply polymer granular materials and foaming gas for constant temperature and pressure continuous foaming and forming, ensure the constancy of the pressure drop during the pressure release process, and finally obtain polymer foamed bead products with uniform quality. This preparation method is simple and reliable, speeds up the production efficiency of products, improves the quality requirements of foamed particle products, and reduces the production cost of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 is a schematic diagram of a constant temperature and pressure continuous foaming and forming device for a microcellular foam particle material provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1

[0034] As Figure 1 shown, the present invention provides a constant-temperature and constant-pressure continuous foaming and forming device for microcellular foam particle materials, including a frame, a constant-pressure feeding system 1 installed on one side of the frame for automatically feeding granular materials under constant pressure, a constant-temperature and constant-pressure gas and liquid supply system 2 installed on one side of the constant-pressure feeding system 1, and a constant-temperature and constant-pressure foaming system 3 installed below the constant-pressure feeding system 1. A pressure balance pipeline 4 is provided between the constant-pressure feeding system 1 and the constant-temperature and constant-pressure foaming system 3, and a pressure balance valve 5 is installed on the constant-pressure feeding system 1.

[0035] Specifically, the constant-pressure feeding system 1 provides automatic constant-pressure feeding of granular materials for the constant-temperature and constant-pressure foaming system 3. At the same time, the constant-temperature and constant-pressure gas and liquid supply system 2 provides constant-temperature and constant-pressure gas and release agent for the constant-temperature and constant-pressure foaming system 3. Then, the constant-temperature and constant-pressure foaming system 3 produces microcellular foam particle materials by stirring the granular materials, gas, and release agent. In this embodiment, the gas is nitrogen and carbon dioxide. The constant-pressure feeding system 1 is connected to the constant-temperature and constant-pressure foaming system 3 through the pressure balance pipeline 4, which can ensure that the air pressures of the constant-pressure feeding system 1 and the constant-temperature and constant-pressure foaming system 3 are equal throughout the production process. In addition, the constant-pressure feeding system 1 releases the excessive internal pressure through the pressure balance valve 5, which ensures the constant-temperature and constant-pressure continuous foaming and forming of the microcellular foam particle materials, improves the quality requirements of the foamed particle products, and has the advantages of compact structure, uniform temperature, constant pressure, stable foaming and forming quality, continuous production, and high production efficiency.

[0036] Specifically, the constant-pressure feeding system 1 includes a polymer particle storage tank 11, a pressure feeder 12, a constant-pressure storage tank 13, a feeder 14, a second control valve 15, a booster pump 16, a pressure relief valve 17, a first control valve 18, a third control valve 19, and a metering feeder 20. The polymer particle storage tank 11 is successively connected to the pressure feeder 12 through the feeder 14 and the second control valve 15. The pressure feeder 12 is connected to the constant-pressure storage tank 13 through the third control valve 19. The pressure relief valve 17 and the booster pump 16 are respectively installed on one side of the pressure feeder 12 and connected to the pressure feeder 12. The first control valve 18 is installed between the booster pump 16 and the pressure feeder 12. The metering feeder 20 is installed below the constant-pressure storage tank 13. The polymer particles inside the constant-pressure storage tank 13 are transported into the constant-temperature and constant-pressure foaming system 3 through the metering feeder 20. The pressure balance pipeline 4 and the pressure balance valve 5 are respectively connected to the constant-pressure storage tank 13.

[0037] Further, when working, the first control valve 18 and the third control valve 19 are closed, and the second control valve 15 is opened. At this time, the pressure feeder 12 is in an atmospheric pressure state. The feeder 14 transports the granular material from the polymer particle storage tank 11 into the pressure feeder 12. When the pressure feeder 12 is filled with granular material, the second control valve 15 is closed, and the first control valve 18 is opened. The booster pump 16 applies pressure (the pressure is 5 - 30 MPa). When this pressure is higher than the pressure in the constant-pressure storage tank 13, the third control valve 19 is opened. Under the action of pressure, the granular material is transported from the pressure feeder 12 into the constant-pressure storage tank 13, and then the metering feeder 20 transports the granular material from the constant-pressure storage tank 13 into the constant-temperature and constant-pressure foaming system 3. The pressure balance valve 5 is used to ensure that the pressures of the constant-pressure storage tank 13 and the constant-temperature and constant-pressure foaming system 3 are kept balanced and consistent. The pressure relief valve 17 is used to empty the pressure inside the pressure feeder 12, so that the inside of the pressure feeder 12 returns to atmospheric pressure. Therefore, the constant-pressure storage tank 13 can supply materials to the constant-temperature and constant-pressure foaming system 3 at a constant air pressure, ensuring the stability of the product foaming and forming quality, and improving the qualified rate and production efficiency of the product.

[0038] Specifically, the constant temperature and pressure gas and liquid supply system 2 includes a liquid nitrogen storage tank 21, a liquid carbon dioxide storage tank 22, an isolating agent liquid storage tank 6, a nitrogen constant pressure and constant temperature storage tank 23, a carbon dioxide constant pressure and constant temperature storage tank 24, a first high-pressure pump 25, a first gas heater 26, a second high-pressure pump 27, a second gas heater 28, a third gas heater 29, a liquid heater 61, and a liquid delivery high-pressure pump 62. The liquid nitrogen storage tank 21 is connected to the nitrogen constant pressure and constant temperature storage tank 23 through the second high-pressure pump 27 and the second gas heater 28 in sequence. The liquid carbon dioxide storage tank 22 is connected to the carbon dioxide constant pressure and constant temperature storage tank 24 through the first high-pressure pump 25 and the first gas heater 26 in sequence. The gases in the nitrogen constant pressure and constant temperature storage tank 23 and the carbon dioxide constant pressure and constant temperature storage tank 24 converge and then enter the constant temperature and pressure foaming system 3 through the third gas heater 29. Flow control valves 30 are installed between the third gas heater 29 and the nitrogen constant pressure and constant temperature storage tank 23, and between the third gas heater 29 and the carbon dioxide constant pressure and constant temperature storage tank 24. The isolating agent liquid storage tank 6 is connected to the constant temperature and pressure foaming system 3 through the liquid delivery high-pressure pump 62 and the liquid heater 61 in sequence. The gas pressure of the constant pressure storage tank is 3 - 30 MPa, and the temperature is 60 - 350 °C.

[0039] Furthermore, the liquid nitrogen storage tank 21 and the liquid carbon dioxide storage tank 22 are used to store liquid media. The liquid carbon dioxide is pressurized by the first high-pressure pump 25 and input into the carbon dioxide constant pressure and constant temperature storage tank 24 for storage through the first gas heater 26. The liquid nitrogen is transported to the nitrogen constant pressure and constant temperature storage tank 23 for storage through the second high-pressure pump 27 and the second gas heater 28 (the pressures and temperatures of the two gases are the same, the pressure is 3 - 30 MPa, and the temperature is 60 - 350 °C). The gases then enter the constant temperature and pressure foaming system 3 through the flow control valves 30 and the gas heater 3 respectively. In addition, the liquid isolating agent in the isolating agent liquid storage tank 6 is pressurized to a pressure of 3 - 30 MPa and heated to a set temperature (temperature range 60 - 300 °C) through the liquid delivery high-pressure pump 62 and the liquid heater 61, and then is input into the constant temperature and pressure foaming system 3. With the above scheme, nitrogen, carbon dioxide gas, and the isolating agent can be transported to the constant temperature and pressure foaming system 3 at a constant temperature and pressure, ensuring the quality stability of product foaming and forming, improving the product qualification rate and production efficiency, and having the advantages of simple process, easy implementation, and high stability.

[0040] Specifically, the constant temperature and pressure foaming system 3 includes a constant temperature and pressure stirring continuous propeller 31, a driving motor 32, a propelling screw 33, and a foam particle storage tank 34. The driving motor 32 is installed on one side of the constant temperature and pressure stirring continuous propeller 31 and fixedly connected to the frame. The propelling screw 33 is installed inside the constant temperature and pressure stirring continuous propeller 31 and is in transmission connection with the driving motor 32. The foam particle storage tank 34 is installed at the discharge port of the constant temperature and pressure stirring continuous propeller 31 and is connected to the constant temperature and pressure stirring continuous propeller 31. In addition, the constant pressure feeding system 1, the constant temperature and pressure gas and liquid supply system 2, and the pressure balance pipeline 4 are respectively connected to the constant temperature and pressure stirring continuous propeller 31.

[0041] Further, in this embodiment, the polymer particles inside the constant pressure storage tank 13 in the constant pressure feeding system 1 are conveyed into the constant temperature and pressure stirring continuous propeller 31 through the metering feeder 20. Nitrogen, carbon dioxide gas, and the separating agent in the constant temperature and pressure gas and liquid supply system 2 can be conveyed into the constant temperature and pressure stirring continuous propeller 31 at a constant temperature and pressure. Since the constant pressure storage tank 13 and the constant temperature and pressure stirring continuous propeller 31 are connected through the pressure balance pipeline 4, it can ensure that the pressures inside the constant pressure storage tank 13 and the constant temperature and pressure stirring continuous propeller 31 are kept consistent. Then, the constant temperature and pressure stirring continuous propeller 31 rotates under the drive of the driving motor 32. The rotation speed of the constant temperature and pressure stirring continuous propeller is 10 - 1000 revolutions per minute. The granular material is conveyed forward under the drive of the propelling screw 33 until it is ejected from the discharge port of the constant temperature and pressure stirring continuous propeller 31 into the foam particle storage tank 34. This solution has the advantages of simple process, easy implementation, and high stability, ensuring the quality stability of the product foaming and forming, and improving the qualified rate and production efficiency of the product.

[0042] The constant temperature and pressure foaming system 3 may further include an adjustable conical foaming particle nozzle 35 installed at the discharge port of the constant temperature and pressure stirring continuous propeller 31. The granular material is ejected at a constant pressure through the adjustable conical foaming particle nozzle 35, and the pressure relief rate is 1 - 1000 MPa / second, finally forming a microcellular foaming particle product. The density of the microcellular foaming particle product is controlled by the opening size of the adjustable conical foaming particle nozzle 35. That is, by adjusting the nozzle gap, the constant pressure drop and pressure relief rate of the system are adjusted to ensure that the system continuously ejects microcellular foaming beads at a constant pressure, obtaining a microcellular foaming bead product with a density of 0.6 - 0.01 g / cm 3 of the microcellular foaming bead product.

[0043] The constant temperature and constant pressure foaming system 3 may further include screw pins 36 and dispersion pins 37 arranged in an array inside the constant temperature and constant pressure stirring continuous pusher 31. When the granular material is conveyed forward under the drive of the pushing screw 33, under the action of the screw pins 36 and the dispersion pins 37, the material is mixed and dispersed to ensure the uniformity of temperature, prevent the adhesion of the granular material, and improve the quality and qualification rate of the product.

[0044] Embodiment 2

[0045] The present invention also provides a preparation method for continuously foaming microporous foam granular materials at constant temperature and constant pressure, including the following preparation steps:

[0046] S1. Transfer the polymer particles in the polymer particle storage tank to the pressure feeder through a feeder, and the pressure feeder quantitatively weighs the polymer particles;

[0047] S2. When the polymer particles in the pressure feeder in step S1 reach a certain mass, transfer the polymer particles in the pressure feeder to the constant pressure storage tank by pressurization. When there is no material in the pressure feeder, the inside of the pressure feeder returns to normal pressure through the connected pressure relief valve, where the gas pressure in the constant pressure storage tank is 3 - 30 MPa and the temperature is 60 - 350 °C;

[0048] S3. Transfer the polymer particles in the constant pressure storage tank (with a pressure of 3 - 30 MPa) in step S2 to the constant temperature and constant pressure stirring continuous pusher through a quantitative feeder. At the same time, constant temperature and constant pressure nitrogen, carbon dioxide, and release agent are simultaneously transported into the constant temperature and constant pressure stirring continuous pusher through flow control valves, where the gas pressure in the constant temperature and constant pressure nitrogen and carbon dioxide storage tanks is 3 - 30 MPa and the temperature is 60 - 350 °C; the liquid pressure of the release agent is 3 - 30 MPa and the temperature is 60 - 350 °C; the rotation speed of the constant temperature and constant pressure stirring continuous pusher is 10 - 1000 revolutions per minute;

[0049] S4. Stir the polymer particles, nitrogen, carbon dioxide, and release agent inside the constant temperature and constant pressure stirring continuous pusher in step S3 by driving the pushing screw with a motor. The formed microporous foam granular material is conveyed forward under the drive of the pushing screw of the constant temperature and constant pressure stirring continuous pusher. The granular material is constantly pressured and ejected from the adjustable conical foaming particle nozzle, and the pressure relief rate is 1 - 1000 MPa / second. Finally, a microporous foaming particle product is formed and collected at the discharge port to obtain microporous foaming beads with a density of 0.6 - 0.01 g / cm 3 ³, and during the whole process, the constant temperature and constant pressure stirring continuous pusher is connected to the constant pressure storage tank described in step S3 through a pressure balance pipeline, and a pressure balance valve is provided on the constant pressure storage tank.

[0050] Specifically, in step S3, nitrogen is formed by heating liquid nitrogen, and carbon dioxide is formed by heating liquid carbon dioxide. The separating agent needs to be heated before being transported to the constant temperature and pressure stirring continuous propeller.

[0051] More specifically, in step S4, at the discharge port of the constant temperature and pressure stirring continuous propeller, a variable cone foaming particle nozzle is connected to adjust the constant pressure drop and pressure relief rate of the system, ensuring that the microporous foamed bead product is continuously ejected from the system at a constant pressure. Inside the constant temperature and pressure stirring continuous propeller in step S4, screw pins and dispersion pins are arranged to mix and disperse the granular materials to ensure the temperature uniformity and prevent the granular materials from sticking together, improving the quality and qualification rate of the product.

[0052] This method can continuously supply the polymer granular materials and the foaming gas for constant pressure continuous foaming molding, ensure the constancy of the pressure drop during the pressure release process, and finally obtain a polymer foamed bead product with uniform quality. This preparation method is simple and reliable, can continuously foam and mold, improves the production efficiency of the product, and reduces the production cost of the product.

[0053] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method for continuously foaming a microporous foam particle material at constant temperature and pressure, characterized in that, it includes a forming device, and the forming device includes a frame. It is characterized in that it further includes a constant-pressure feeding system (1) installed on one side of the frame for automatically feeding granular materials under constant pressure, a constant-temperature and constant-pressure gas and liquid supply system (2) installed on one side of the constant-pressure feeding system (1), and a constant-temperature and constant-pressure foaming system (3) installed below the constant-pressure feeding system (1). A pressure balance pipeline (4) is provided between the constant-pressure feeding system (1) and the constant-temperature and constant-pressure foaming system (3), and a pressure balance valve (5) is installed on the constant-pressure feeding system (1); It further includes the following preparation steps: S1. Transfer the polymer particles in the polymer particle storage tank (11) to the pressure feeder (12) through a feeder (14), and the pressure feeder (12) quantitatively weighs the polymer particles; S2. When the polymer particles in the pressure feeder (12) in step S1 reach a certain mass, transfer the polymer particles in the pressure feeder (12) to the constant-pressure storage tank (13) by pressurization. When there is no material in the pressure feeder (12), the inside of the pressure feeder (12) returns to normal pressure through a communicating pressure relief valve (17). The gas pressure of the constant-pressure storage tank (13) is 3 - 30 MPa, and the temperature is 60 - 350 °C; S3. Transfer the polymer particles in the constant-pressure storage tank (13) in step S2 to the constant-temperature and constant-pressure stirring continuous pusher (31) through a quantitative feeder (20). At the same time, constant-temperature and constant-pressure nitrogen, carbon dioxide, and release agent are simultaneously transported into the constant-temperature and constant-pressure stirring continuous pusher (31) through a flow control valve (30). The gas pressure of the constant-temperature and constant-pressure nitrogen and carbon dioxide storage tanks is 3 - 30 MPa, and the temperature is 60 - 350 °C; the liquid pressure of the release agent is 3 - 30 MPa, and the temperature is 60 - 350 °C; the rotation speed of the constant-temperature and constant-pressure stirring continuous pusher (31) is 10 - 1000 revolutions per minute; S4. Stir the polymer particles, nitrogen, carbon dioxide, and release agent inside the constant-temperature and constant-pressure stirring continuous pusher (31) in step S3 by driving the screw with a driving motor (32). The formed microporous foam particle material is transported forward under the drive of the screw of the constant-temperature and constant-pressure stirring continuous pusher (31). The granular material is ejected at a constant pressure from an adjustable conical foaming particle nozzle (35), and the pressure relief rate is 1 - 1000 MPa / second. Finally, a microporous foamed particle product is formed and collected at the discharge port to obtain microporous foamed beads with a density of 0.6 - 0.01 g / cm3. During the whole process, the constant-temperature and constant-pressure stirring continuous pusher (31) is connected to the constant-pressure storage tank (13) in step S3 through a pressure balance pipeline (4), and a pressure balance valve (5) is provided on the constant-pressure storage tank (13).

2. The preparation method for continuously foaming a microporous foam particle material at constant temperature and pressure according to claim 1, characterized in that, The constant-pressure feeding system (1) includes a polymer particle storage tank (11) installed on a frame, a pressure feeder (12) communicated with the polymer particle storage tank (11), a constant-pressure storage tank (13) communicated with the pressure feeder (12), a feeder (14) and a second control valve (15) installed between the polymer particle storage tank (11) and the pressure feeder (12), a booster pump (16) and a pressure relief valve (17) respectively installed on one side of the pressure feeder (12) and communicated with the pressure feeder (12), a first control valve (18) installed between the booster pump (16) and the pressure feeder (12), a third control valve (19) installed between the pressure feeder (12) and the constant-pressure storage tank (13), and a metering feeder (20) installed below the constant-pressure storage tank (13). The pressure balance pipeline (4) and the pressure balance valve (5) are respectively communicated with the constant-pressure storage tank (13).

3. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 1, characterized in that, the constant-temperature and constant-pressure gas and liquid supply system (2) includes a liquid nitrogen storage tank (21), a liquid carbon dioxide storage tank (22) and an isolating agent liquid storage tank (6) respectively installed on one side of the frame, a nitrogen constant-temperature and constant-pressure storage tank (23) communicated with the liquid nitrogen storage tank (21), a carbon dioxide constant-temperature and constant-pressure storage tank (24) communicated with the liquid carbon dioxide storage tank (22), a first high-pressure pump (25) installed between the liquid carbon dioxide storage tank (22) and the carbon dioxide constant-temperature and constant-pressure storage tank (24), a first gas heater (26) installed between the first high-pressure pump (25) and the carbon dioxide constant-temperature and constant-pressure storage tank (24), a second high-pressure pump (27) installed between the liquid nitrogen storage tank (21) and the nitrogen constant-temperature and constant-pressure storage tank (23), a second gas heater (28) installed between the second high-pressure pump (27) and the nitrogen constant-temperature and constant-pressure storage tank (23). The gases in the nitrogen constant-temperature and constant-pressure storage tank (23) and the carbon dioxide constant-temperature and constant-pressure storage tank (24) converge and then enter the constant-temperature and constant-pressure foaming system (3). A third gas heater (29) is installed at the gas convergence point of the nitrogen constant-temperature and constant-pressure storage tank (23) and the carbon dioxide constant-temperature and constant-pressure storage tank (24). Flow control valves (30) are installed between the third gas heater (29) and the nitrogen constant-temperature and constant-pressure storage tank (23), and between the third gas heater (29) and the carbon dioxide constant-temperature and constant-pressure storage tank (24). The isolating agent liquid storage tank (6) is communicated with the constant-temperature and constant-pressure foaming system (3). A liquid heater (61) is installed between the isolating agent liquid storage tank (6) and the constant-temperature and constant-pressure foaming system (3). A liquid delivery high-pressure pump (62) is installed between the liquid heater (61) and the isolating agent liquid storage tank (6).

4. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 1, characterized in that, The constant temperature and constant pressure foaming system (3) includes a constant temperature and constant pressure stirring continuous pusher (31) installed on a frame, a driving motor (32) installed on one side of the constant temperature and constant pressure stirring continuous pusher (31) and fixedly connected to the frame, a propulsion screw (33) installed inside the constant temperature and constant pressure stirring continuous pusher (31) and drivingly connected to the driving motor (32), a foam particle storage tank (34) installed at the discharge port of the constant temperature and constant pressure stirring continuous pusher (31) and communicating with the constant temperature and constant pressure stirring continuous pusher (31). The constant pressure feeding system (1), the constant temperature and constant pressure gas and liquid supply system (2) and the pressure balance pipeline (4) are respectively communicated with the constant temperature and constant pressure stirring continuous pusher (31).

5. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 4, characterized in that, an adjustable conical foaming particle nozzle (35) communicating with the constant temperature and constant pressure stirring continuous pusher (31) is installed at the discharge port of the constant temperature and constant pressure stirring continuous pusher (31).

6. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 4, characterized in that, screw pins (36) and dispersion pins (37) arranged in an array are installed inside the constant temperature and constant pressure stirring continuous pusher (31).

7. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 1, characterized in that, in step S3, nitrogen is formed by heating liquid nitrogen, and carbon dioxide is formed by heating liquid carbon dioxide.

8. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 1, characterized in that, in step S4, the discharge port of the constant temperature and constant pressure stirring continuous pusher adjusts the constant pressure drop and pressure relief rate of the system by connecting an adjustable conical foaming particle nozzle, ensuring that the system continuously sprays microporous foaming beads at a constant pressure, and obtaining a microporous foaming bead product with a density of 0.6 - 0.01 g / cm3.

9. The preparation method for continuously foaming a microporous foam particle material at constant temperature and constant pressure according to claim 1, characterized in that, in step S4, screw pins and dispersion pins are arranged inside the constant temperature and constant pressure stirring continuous pusher to mix and disperse the particulate material to ensure temperature uniformity and prevent the particulate material from sticking.

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