CN112851999A - Method for preparing high-foaming-ratio polymer-based foam beads through secondary foaming - Google Patents
Method for preparing high-foaming-ratio polymer-based foam beads through secondary foaming Download PDFInfo
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- C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
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- C08J2201/00—Foams characterised by the foaming process
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- C08J2201/034—Post-expanding of foam beads or sheets
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- C08J2329/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
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- C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
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Abstract
The invention discloses a method for preparing high-expansion-ratio polymer-based foam beads through secondary foaming, which comprises the following steps: placing the polymer-based beads in an autoclave, introducing carbon dioxide gas, allowing the carbon dioxide gas to reach a supercritical state under a primary foaming condition, performing primary foaming on the polymer-based beads in a supercritical carbon dioxide gas environment, and relieving pressure to obtain primary foamed beads; and placing the primary foamed beads obtained through the primary foaming process into the high-pressure kettle again, introducing a physical foaming agent, carrying out secondary foaming under the condition of secondary foaming, and relieving pressure to obtain the high-foaming-ratio polymer-based foamed beads. The novel bead foaming technology disclosed by the invention overcomes the problem that the conventional foaming method can only prepare the foaming beads with lower expansion ratio, widens the application range of bead foaming in polymer materials, can prepare large-scale and high-expansion-ratio polymer foam products, and has application prospects in important fields of high and new technology industries.
Description
Technical Field
The application relates to the technical field of bead foaming, in particular to a supercritical carbon dioxide bead foaming technology for preparing high-foaming-ratio polymer foam materials and products thereof.
Background
The polymer foam material is a material with gas distributed in a polymer matrix, has excellent performances of light weight, heat insulation, adsorption and sound absorption and the like, and is widely applied to the fields of buildings, packaging, transportation, aviation and the like. The rapid development of national economy and high and new technologies urgently requires high-strength heat-resistant high-performance foam materials.
The polymer bead foam is generally formed by molding foaming, extrusion foaming, injection molding foaming, bead foaming, and the like. The bead foaming is a foaming mode of welding expandable or sent beads, and can prepare a bead foam product with high precision, high foaming ratio and complex shape. The general preparation process includes preparation of the beads and fusion of the beads. Such as expandable polystyrene beads, are prepared by impregnating the beads with a physical blowing agent during suspension polymerization. However, most of the general polymer beads are formed beads, and the volume, density, etc. of the final product are determined by the expansion ratio of the formed beads. The most widely used at present are mainly general-purpose plastic beads, such as expandable and expandable polystyrene beads, expandable polyethylene and polypropylene beads, and the like. The most widely applied method for preparing the beads is a high-pressure impregnation method, wherein a polymer, a foaming agent and the like are placed in a high-pressure kettle, the resin is softened by heating, so that the foaming agent is fully impregnated in a resin matrix, and the foaming agent is escaped by instantly reducing the temperature and the pressure to prepare the polymer foaming beads. The high-strength and heat-resistant foam beads such as engineering plastics, special engineering plastics and the like required by the high and new technology industry are difficult to prepare polymer beads with high expansion ratio due to high strength and high glass transition temperature, and the density of the polymer beads is difficult to be greatly reduced, so that the light weight of the polymer beads is reduced, and the wide application of the polymer beads is greatly limited.
Therefore, the development of a novel and universal bead foaming technology makes more high-performance polymer materials, especially high-strength, high-glass transition temperature and excellent mechanical properties, suitable for bead foaming, and obtains bead foam with high foaming ratio by adjusting a foaming method, thereby becoming a key for preparing high-ratio and high-strength polymer foam materials.
The supercritical carbon dioxide is in a state that the carbon dioxide is at the critical temperature (31.1 ℃) and the critical pressure (7.37MPa) or above, is non-toxic, non-combustible, high in chemical stability, free of solvent residue, safe to use, free of environmental pollution, rich in source, and has the density close to that of liquid and the diffusion coefficient and viscosity close to that of gas in the supercritical state. The carbon dioxide gas can realize supercritical operation at room temperature, and is an ideal polymer foam physical foaming agent. The supercritical carbon dioxide foaming process of the polymer mainly comprises three stages: formation of a polymer/carbon dioxide homogeneous system, bubble nucleation and bubble growth. The solubility of carbon dioxide in the polymer matrix greatly affects the degree of foaming of the final polymer beads. For general plastics with lower glass transition temperature, such as polyethylene, polypropylene and other polymer materials, polymer beads with high expansion ratio can be easily obtained by using a supercritical carbon dioxide foaming method, for polymer materials with high strength, high performance and high glass transition temperature, such as polyvinyl alcohol, polycarbonate, polysulfone and the like, the polymer beads with high expansion ratio can be hardly prepared even by using supercritical carbon dioxide foaming, and the foaming process has high requirements on equipment, needs to bear high temperature and high pressure and consumes too long time.
Disclosure of Invention
The invention aims to: the method for preparing the polymer-based foam beads with high foaming ratio by secondary foaming is provided, the polymer foam beads with high foaming ratio are prepared by secondary foaming of supercritical carbon dioxide under mild conditions, and the problem that a large-scale high-performance polymer foam material with light weight and low density is difficult to prepare in the prior art is solved.
The invention provides a method for preparing high-expansion-ratio polymer-based foam beads through secondary foaming, which comprises the following steps of:
step 1, placing polymer-based beads in an autoclave, introducing carbon dioxide gas, allowing the carbon dioxide gas to reach a supercritical state under a primary foaming condition, performing primary foaming on the polymer-based beads in a supercritical carbon dioxide gas environment, and relieving pressure to obtain primary foamed beads;
and 2, placing the primary foamed beads into the high-pressure kettle again, introducing a physical foaming agent, carrying out secondary foaming under the condition of secondary foaming, and relieving pressure to obtain the high-foaming-ratio polymer-based foamed beads.
Preferably, in the step 1, the primary foaming conditions include: the temperature is 20-50 deg.C lower than the melting point of the polymer, the pressure is 10-15Mpa, and the soaking time is 10-60 min.
Preferably, in the step 1, the primary expanded beads have an expansion ratio of 1 to 4 times and a pore size of 0 to 50 μm.
Preferably, in the step 1, the polymer-based bead includes any one of a single polymer system, a polymer/inorganic filler composite system, and a polymer blend system.
Preferably, the single polymer system comprises: polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide.
Preferably, the polymer/inorganic filler composite system; wherein the polymer comprises: at least one of polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide; the inorganic filler comprises at least one of graphite, carbon fiber, carbon nano tube, graphene, barium titanate, calcium carbonate, ferroferric oxide, hydroxyapatite and water glass.
Preferably, the polymer blend system comprises: polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide.
Preferably, in the step 2, the secondary foaming conditions include: the temperature is 40-100 deg.C, the pressure is 6-8MPa, and the soaking time is 30-120 min.
Preferably, in the step 2, the physical foaming agent is at least one of carbon dioxide, carbon dioxide/nitrogen, carbon dioxide/ethanol, carbon dioxide/water, carbon dioxide/acetone, and carbon dioxide/tetrahydrofuran.
Compared with the prior art, the method has the following advantages:
according to the invention, the polymer-based foam beads with high foaming ratio and high performance are obtained under mild conditions by adjusting the ratio of primary foaming, and the physical foaming agent adopted by secondary foaming, pressure, time, temperature and the like, so that the limitation of the traditional foaming technology is broken through, and a solid foundation is laid for widening the application of high-performance bead foam.
According to the invention, through deeply researching the relationship between the secondary bead foaming multiplying power and the primary foaming multiplying power, the physical foaming agent, the dipping time, the foaming temperature, the pressure relief rate and the like, the influence of the secondary bead foaming multiplying power and the interaction of different materials, the secondary bead foaming principle and the skin layer thickness on the carbon dioxide infiltration amount and the expandability is researched, the bead foaming technology disclosed by the invention is established, and the method has very important significance for preparing a high-expansion multiplying power and high-performance polymer foam product.
The technology for preparing the high-foaming-ratio polymer-based foam beads through secondary foaming has the characteristics of simplicity and high efficiency, and the polymer beads with a certain cell structure and a thin skin layer are obtained through simple primary supercritical carbon dioxide foaming, so that the infiltration amount of a physical foaming agent is greatly increased in the secondary foaming process of the polymer beads, the high-foaming-ratio polymer-based foam beads are obtained through low-temperature, low-pressure and short-time impregnation, and a large amount of time and equipment cost are saved.
The method provided by the invention has high universality, is generally suitable for polymer materials and polymer blending materials, overcomes the problem that the conventional foaming method is difficult to prepare high-performance polymer bead foam materials with high expansion ratio, is suitable for the bead foaming of amorphous polymers with high glass transition temperature or crystalline polymers with high melting point, widens the application range of the bead foaming in the polymer materials, and provides an effective way for preparing high-performance multifunctional polymer foam materials with high foaming ratio and products thereof.
The technical scheme of the invention has simple process, is suitable for continuous production, has good market popularization value, and can meet the requirements of high and new technology industries, particularly aerospace and other fields.
Drawings
FIG. 1 is a flow chart of a method for preparing high expansion ratio polymer-based foam beads by secondary foaming according to an embodiment of the present invention;
FIG. 2(a) is an external view showing polyvinyl alcohol beads in example 1 of the present invention;
FIG. 2(b) is a view showing the external appearance of primary expanded beads obtained by primary expansion in example 1 of the present invention;
FIG. 2(c) is a view showing the external appearance of a secondary expanded bead foam obtained by secondary expansion in example 1 of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is described in further detail with reference to the accompanying drawings and the detailed description.
FIG. 1 shows a flow chart of a method for preparing high expansion ratio polymer-based foam beads by secondary foaming. Referring to fig. 1, the present invention provides a method for preparing high expansion ratio polymer-based foam beads by secondary foaming, which comprises the following steps:
s11, placing the polymer-based beads in an autoclave, introducing carbon dioxide gas, allowing the carbon dioxide gas to reach a supercritical state under a primary foaming condition, performing primary foaming on the polymer-based beads in a supercritical carbon dioxide gas environment, and relieving pressure to obtain primary foamed beads;
and S12, placing the primary expanded beads obtained in the S11 in the high-pressure kettle again, introducing a physical foaming agent, carrying out secondary expansion under the condition of secondary expansion, and relieving pressure to obtain the high-expansion-ratio polymer-based expanded beads.
In specific implementation, the polymer-based beads are obtained by melting and blending a single polymer system, a polymer/inorganic filler composite system and a polymer blending system by adopting a single-screw or double-screw extruder, extruding and granulating through a capillary die, and obtaining positive column polymer-based beads by matching the traction speed and the rotating speed of a cutter, or obtaining spherical polymer-based beads by adopting underwater granulation; placing the obtained polymer-based beads in a high-pressure kettle, introducing carbon dioxide gas to remove air in the kettle, continuously introducing the carbon dioxide gas after a sealing device is sealed, enabling the pressure in the reaction kettle to reach a primary foaming pressure, heating to a primary foaming temperature, enabling the carbon dioxide gas to reach a supercritical state, and after a certain impregnation time, releasing pressure to obtain primary foaming beads; and then standing the obtained primary foamed beads in the air for a while, putting the primary foamed beads in the high-pressure kettle again, sealing the device, introducing a physical foaming agent to ensure that the pressure in the reaction kettle reaches a secondary foaming pressure, heating to a secondary foaming temperature, at the moment, allowing carbon dioxide gas to reach a supercritical state, soaking for a period of time, and then releasing pressure to obtain the high-expansion-ratio polymer-based foamed beads.
The formation of a polymer/carbon dioxide homogeneous system is critical to the subsequent foaming process, and the maximum solubility of carbon dioxide in the polymer matrix can be expressed by henry's law: cs＝HPsIn which C issH is the Henry constant, P, for the solubility of a gas in a polymersIs the saturation pressure. The henry constant can in turn be expressed as:
wherein R is the gas constant, T is the temperature, H0Is a coefficient of solubility ofCounting; Δ HsIs the amount of adsorption heat, depending on the particular polymer-gas system. From the above, we can find that when the external temperature and pressure conditions are fixed, the dissolution of carbon dioxide in the polymer is determined by the interaction between the polymer and carbon dioxide (i.e. the nature of the polymer). For high-performance polymer materials, particularly engineering plastics or special engineering plastics, molecular chains of the high-performance polymer materials are rigid, the glass transition temperature is high, the molecular chains are difficult to move at low temperature, and the absorption rate of carbon dioxide is low, so that high-pressure impregnation for a long time (6h) is needed to ensure that more carbon dioxide can be immersed into a matrix, further nucleation and growth can be realized in the subsequent process, but even under the conditions of high temperature and high pressure (230 ℃ and 25MPa), the foaming ratio is still limited, and a bead foam product with high foaming ratio is difficult to obtain. The term "supercritical carbon dioxide secondary foaming" in the present invention refers to a polymer bead with low foaming ratio (no need of long-time impregnation, high temperature and high pressure) obtained after the first foaming of the polymer, placing the foamed bead in a kettle again, and impregnating the foamed bead with a physical foaming agent at a low temperature, wherein the absorption of the polymer bead on the physical foaming agent is greatly improved, and the secondary foaming can be completed within a low-temperature, low-pressure and low-impregnation time to obtain a high-foaming-ratio polymer bead foam. Therefore, the high-performance polymer bead foam with high expansion ratio under mild conditions is obtained by adjusting the expansion ratio of the first foaming, the physical foaming agent adopted by the second foaming, the pressure, the time, the temperature and the like.
Preferably, in step 1, the primary foaming conditions include: the temperature is 20-50 deg.C lower than the melting point of the polymer, the pressure is 10-15Mpa, and the soaking time is 10-60 min.
Preferably, in step 1, the primary expanded beads have an expansion ratio of 1 to 4 times and a pore size of 0 to 50 μm.
In the specific implementation, the expansion ratio of the beads may be determined by a method of measuring the density of the beads, or may be determined by a method of measuring the volume of the beads. Preferably, the expansion ratio is determined by using the ratio of the volume of the expanded beads to the volume of the beads before the expansion.
Preferably, in step 1, the polymer-based beads include any one of a single polymer system, a polymer/inorganic filler composite system, and a polymer blend system.
Preferably, the single polymer system comprises: polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide.
Preferably, a polymer/inorganic filler composite system; wherein the polymer comprises: at least one of polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide; the inorganic filler comprises at least one of graphite, carbon fiber, carbon nano tube, graphene, barium titanate, calcium carbonate, ferroferric oxide, hydroxyapatite and water glass.
Preferably, the polymer blend system comprises: polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide.
Preferably, in step 2, the secondary foaming conditions include: the temperature is 40-100 deg.C, the pressure is 6-8MPa, and the soaking time is 30-120 min.
In specific implementation, the secondary foaming multiplying power of the invention is obviously improved compared with the primary foaming. For example: the polyvinyl alcohol beads are soaked for 1-2h under primary foaming (the most suitable condition is that the temperature is 165-170 ℃, and the pressure is 20-25MPa), and the foaming ratio is only 5-7 times. In the invention, the primary foaming only needs 135-155 ℃ without impregnation, and the pressure is 10-15 MPa. The obtained bead has a low expansion ratio of 2-4 times and a cell size of 10-50 μm. Through secondary carbon dioxide foaming, the conditions are extremely mild, and the temperature is as follows: soaking at 40 deg.C for 0.5-1h under 7-8MPa to obtain foamed polyvinyl alcohol beads with foaming ratio of 10-20 times.
Preferably, in step 2, the physical blowing agent is at least one of carbon dioxide, carbon dioxide/nitrogen, carbon dioxide/ethanol, carbon dioxide/water, carbon dioxide/acetone, carbon dioxide/tetrahydrofuran.
In order that the present invention may be more clearly understood by those skilled in the art, the process of the present invention will now be described in detail by way of the following non-limiting examples.
Example 1:
500g of polyvinyl alcohol granules (shown in figure 2 (a)) are placed in a stainless steel mold and placed in an autoclave, the temperature is raised to 35 ℃, carbon dioxide gas is introduced, the pressure is raised to 6-7MPa after the air in the autoclave is discharged, then the temperature is raised to 135-155 ℃ within 20min, and then the pressure is released at the speed of 5MPa/s to obtain primary foamed beads. As shown in FIG. 2(b), the primary expanded beads had a cell size of 10 to 50 μm and an expansion ratio of 2 to 4 times. And then standing the beads obtained by the primary foaming in the air for a while, then placing the beads in the high-pressure kettle again, raising the temperature to 40 ℃, introducing carbon dioxide gas, exhausting the air in the kettle, boosting the pressure to 6-7MPa, soaking for 0.5-1h, and then releasing the pressure at the speed of 5MPa/s to obtain secondary foaming bead foam. As shown in FIG. 2(c), the expansion ratio of the secondary expanded bead foam was 10 to 20 times.
Example 2:
placing 500g of polycarbonate granules in a stainless steel mold, placing the stainless steel mold in an autoclave, raising the temperature to 35 ℃, introducing carbon dioxide gas, exhausting the air in the autoclave, raising the pressure to 6-7MPa, raising the temperature to 140-160 ℃ within 25min, and then releasing the pressure at the speed of 5MPa/s to obtain the primary foamed beads. The primary expanded beads have a cell size of 10 to 30 μm and a foaming ratio of 1.5 to 3.5 times. And then standing the beads obtained by the primary foaming in the air for a while, then placing the beads in the high-pressure kettle again, raising the temperature to 60-90 ℃, introducing carbon dioxide gas, discharging the air in the kettle, raising the pressure to 6-7MPa, soaking for 1h, and then releasing the pressure at the speed of 5MPa/s to obtain secondary foaming bead foam, wherein the foaming multiplying power is 8-16 times.
It should be noted that in this example, the appearance before foaming, the appearance after primary foaming, and the appearance after secondary foaming are similar to those in example 1, and the differences are only colors and sizes, and therefore, in order to save the space of the drawings, the description is not repeated in this example.
Example 3:
500g of polysulfone granules are placed in a stainless steel mold and placed in an autoclave, the temperature is raised to 35 ℃, carbon dioxide gas is introduced, the pressure is raised to 6-7MPa after the air in the autoclave is discharged, then the temperature is raised to 155-. The primary foamed bead has a cell size of 10 to 30 μm and a foaming ratio of 2 to 3.5 times. And then standing the beads obtained by primary foaming in the air for a while, then placing the beads in the high-pressure kettle again, adding a proper amount of ethanol solution into the kettle, heating to 60-80 ℃, introducing carbon dioxide gas, discharging the air in the kettle, boosting the pressure to 6-7MPa, soaking for 1h, and then releasing the pressure at the speed of 5MPa/s to obtain secondary foaming bead foam, wherein the foaming multiplying power is 7-15 times.
It should be noted that in this example, the appearance before foaming, the appearance after primary foaming, and the appearance after secondary foaming are similar to those in example 1, and the differences are only colors and sizes, and therefore, in order to save the space of the drawings, the description is not repeated in this example.
Example 4:
500g of polyvinyl alcohol and barium titanate are respectively added into a charging barrel of an extruder, the extrusion temperature is set to be 175-200 ℃, the materials are heated and sheared by a screw to be melted, and the materials are extruded from a neck mold after passing through a cooling section. And then granulating to obtain polyvinyl alcohol/barium titanate composite granules with the size of about 2 mm. And then placing the composite beads in a stainless steel mold, placing the stainless steel mold in an autoclave, raising the temperature to 35 ℃, introducing carbon dioxide gas, exhausting the air in the autoclave, raising the pressure to 6-7MPa, raising the temperature to 135-155 ℃ within 20min, and then releasing the pressure at the speed of 5MPa/s to obtain primary foamed beads. The primary expanded beads have a cell size of 10 to 40 μm and a foaming ratio of 1.5 to 3.5 times. And then standing the beads obtained by the primary foaming in the air for a while, then placing the beads in the high-pressure kettle again, raising the temperature to 40-60 ℃, introducing carbon dioxide gas, discharging the air in the kettle, raising the pressure to 6-7MPa, soaking for 0.5-1h, and then releasing the pressure at the speed of 5MPa/s to obtain secondary foaming bead foam, wherein the foaming multiplying power is 8-16 times.
It should be noted that in this example, the appearance before foaming, the appearance after primary foaming, and the appearance after secondary foaming are similar to those in example 1, and the differences are only colors and sizes, and therefore, in order to save the space of the drawings, the description is not repeated in this example.
Example 5:
500g of polysulfone and calcium carbonate are respectively added into a charging barrel of an extruder, the extrusion temperature is set at 280-300 ℃, the polysulfone and the calcium carbonate are melted by heating and shearing through a screw, and the polysulfone and the calcium carbonate are extruded from a neck mold after passing through a temperature reduction section. And then cutting into granules to obtain the polysulfone/calcium carbonate composite granules with the size of about 2 mm. Placing the composite particles in a stainless steel mold, placing the stainless steel mold in a high-pressure kettle, heating to 35 ℃, introducing carbon dioxide gas, exhausting air in the kettle, boosting to 6-7MPa, then heating to 160-180 ℃ within 30min, and then decompressing at the speed of 5MPa/s to obtain primary foaming beads. The primary foamed bead has a cell size of 10 to 20 μm and a foaming ratio of 1.5 to 3 times. And then standing the beads obtained by primary foaming in the air for a while, then placing the beads in the high-pressure kettle again, adding a proper amount of acetone solution into the kettle, heating to 60-80 ℃, introducing carbon dioxide gas, discharging the air in the kettle, boosting the pressure to 6-7MPa, soaking for 1h, and then releasing the pressure at the speed of 5MPa/s to obtain secondary foaming bead foam, wherein the foaming multiplying power is 6-12 times.
It should be noted that in this example, the appearance before foaming, the appearance after primary foaming, and the appearance after secondary foaming are similar to those in example 1, and the differences are only colors and sizes, and therefore, in order to save the space of the drawings, the description is not repeated in this example.
Example 6:
500g of poly (butylene adipate/terephthalate) and polylactic acid are respectively added into a charging barrel of an extruder, the extrusion temperature is set to be 170-190 ℃, the materials are heated and sheared by a screw to be melted, and the materials are extruded from a neck mold after passing through a temperature reduction section. And then cutting into granules to obtain the poly adipic acid/butylene terephthalate/polylactic acid composite granules with the size of about 2 mm. Placing the composite beads in a stainless steel mold, placing the stainless steel mold in an autoclave, heating to 35 ℃, introducing carbon dioxide gas, discharging air in the autoclave, boosting the pressure to 6-7MPa, then heating to 80-100 ℃ for 15min, and then decompressing at the speed of 5MPa/s to obtain primary foamed beads. The primary foaming bead has a cell size of 10 to 50 μm and a foaming ratio of 2 to 4 times. And then standing the beads obtained by primary foaming in air for a while, then placing the beads in the high-pressure kettle again, raising the temperature to 35 ℃, introducing carbon dioxide gas, exhausting the air in the kettle, boosting the pressure to 6-7MPa, soaking for 1h, and then releasing the pressure at the speed of 5MPa/s to obtain secondary foaming bead foam, wherein the foaming multiplying power is 8-18 times.
It should be noted that in this example, the appearance before foaming, the appearance after primary foaming, and the appearance after secondary foaming are similar to those in example 1, and the differences are only colors and sizes, and therefore, in order to save the space of the drawings, the description is not repeated in this example.
For simplicity of explanation, the method embodiments are described as a series of acts or combinations, but those skilled in the art will appreciate that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are preferred embodiments and that the acts and elements referred to are not necessarily required to practice the invention.
The method for preparing the high-expansion-ratio polymer foam beads through the secondary foaming of the supercritical carbon dioxide is described in detail, the principle and the implementation mode of the invention are explained by applying specific examples, and the description of the examples is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A method for preparing high-expansion-ratio polymer-based foam beads through secondary foaming is characterized by comprising the following steps of: the method for preparing the high-expansion-ratio polymer-based foam beads through secondary foaming is completed according to the following steps:
step 1, placing polymer-based beads in an autoclave, introducing carbon dioxide gas, allowing the carbon dioxide gas to reach a supercritical state under a primary foaming condition, performing primary foaming on the polymer-based beads in a supercritical carbon dioxide gas environment, and relieving pressure to obtain primary foamed beads;
and 2, placing the primary foamed beads into the high-pressure kettle again, introducing a physical foaming agent, carrying out secondary foaming under the condition of secondary foaming, and relieving pressure to obtain the high-foaming-ratio polymer-based foamed beads.
2. The method of claim 1, wherein: in the step 1, the primary foaming conditions include: the temperature is 20-50 deg.C lower than the melting point of the polymer, the pressure is 10-15Mpa, and the soaking time is 10-60 min.
3. The method of claim 1, wherein: in the step 1, the primary expanded beads have an expansion ratio of 1 to 4 times and a pore size of O-50 μm.
4. The method of claim 1, wherein: in the step 1, the polymer-based bead includes any one of a single polymer system, a polymer/inorganic filler composite system, and a polymer blend system.
5. The method of claim 4, wherein: the single polymer system comprises: polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide.
6. The method of claim 4, wherein: the polymer/inorganic filler composite system; wherein the polymer comprises: at least one of polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide; the inorganic filler comprises at least one of graphite, carbon fiber, carbon nano tube, graphene, barium titanate, calcium carbonate, ferroferric oxide, hydroxyapatite and water glass.
7. The method of claim 4, wherein: the polymer blend system comprises: polyvinyl alcohol, polybutylene adipate/terephthalate, polylactic acid, polycarbonate, polysulfone, polyetherimide and polyimide.
8. The method of claim 1, wherein: in the step 2, the secondary foaming conditions include: the temperature is 40-100 deg.C, the pressure is 6-8MPa, and the soaking time is 30-120 min.
9. The method of claim 1, wherein: in the step 2, the physical foaming agent is at least one of carbon dioxide, carbon dioxide/nitrogen, carbon dioxide/ethanol, carbon dioxide/water, carbon dioxide/acetone, and carbon dioxide/tetrahydrofuran.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113416341A (en) * | 2021-06-01 | 2021-09-21 | 中山大学 | Polyester expanded bead, polyester expanded bead molded body and preparation method thereof |
| CN115805688A (en) * | 2022-12-13 | 2023-03-17 | 苏州申赛新材料有限公司 | Method for preparing polymer foam material with open pore structure |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104130439A (en) * | 2014-08-11 | 2014-11-05 | 邓婷 | Thermoplastic polyurethane elastomer foamed beads and preparation method thereof |
| KR101555612B1 (en) * | 2015-02-16 | 2015-10-06 | 홍성현 | Preparation method of drivit associate nonflammable expanded polystyrene for facing material of building |
| CN104974370A (en) * | 2015-01-19 | 2015-10-14 | 常州市顺祥新材料科技有限公司 | Preparation method of thermoplastic polyurethane beads and bead molding technology |
| CN108659251A (en) * | 2017-03-29 | 2018-10-16 | 深圳市科聚新材料有限公司 | The preparation method of polyetherimide expanded particle |
| CN110054835A (en) * | 2019-03-27 | 2019-07-26 | 无锡会通轻质材料股份有限公司 | A kind of preparation method of high magnification conductivity type polypropylene foaming beads |
| CN111410765A (en) * | 2020-03-26 | 2020-07-14 | 中山大学 | Preparation method of biodegradable polyester expanded bead and molded body material |
-
2021
- 2021-01-11 CN CN202110032981.8A patent/CN112851999A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104130439A (en) * | 2014-08-11 | 2014-11-05 | 邓婷 | Thermoplastic polyurethane elastomer foamed beads and preparation method thereof |
| CN104974370A (en) * | 2015-01-19 | 2015-10-14 | 常州市顺祥新材料科技有限公司 | Preparation method of thermoplastic polyurethane beads and bead molding technology |
| KR101555612B1 (en) * | 2015-02-16 | 2015-10-06 | 홍성현 | Preparation method of drivit associate nonflammable expanded polystyrene for facing material of building |
| CN108659251A (en) * | 2017-03-29 | 2018-10-16 | 深圳市科聚新材料有限公司 | The preparation method of polyetherimide expanded particle |
| CN110054835A (en) * | 2019-03-27 | 2019-07-26 | 无锡会通轻质材料股份有限公司 | A kind of preparation method of high magnification conductivity type polypropylene foaming beads |
| CN111410765A (en) * | 2020-03-26 | 2020-07-14 | 中山大学 | Preparation method of biodegradable polyester expanded bead and molded body material |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113416341A (en) * | 2021-06-01 | 2021-09-21 | 中山大学 | Polyester expanded bead, polyester expanded bead molded body and preparation method thereof |
| CN113416341B (en) * | 2021-06-01 | 2022-05-24 | 中山大学 | Polyester expanded bead, polyester expanded bead molded body and preparation method thereof |
| CN115805688A (en) * | 2022-12-13 | 2023-03-17 | 苏州申赛新材料有限公司 | Method for preparing polymer foam material with open pore structure |
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Application publication date: 20210528 |