Thermoplastic resin composite foam material and preparation method thereof

Abstract

The invention belongs to the technical field of polymer processing, and particularly relates to a thermoplastic resin composite foam material and a preparation method thereof. The preparation method comprises the following steps: carrying out melt blending on thermoplastic resin, an acrylate modifier, a lubricant, a heat stabilizer, a thermosetting polymer, an auxiliary plasticizer and an auxiliary curing agent, carrying out hot pressing on an obtained polymer base material, saturating the polymer base material in high-pressure gas, carrying out pressure relief, placing the obtained saturated base material in water, and carrying out microwave heating to obtain the thermoplastic resin composite foam material. According to the preparation method, melting mixing, high-pressure gas saturation, microwave heating foaming and curing are associated with one another, and from preparation to foaming and curing, fusion of all the components is greatly improved, the glass-transition temperature of the foaming material and the uniformity of a foam structure are improved, and the production process of the foaming material is simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer processing, and particularly relates to a thermoplastic resin composite foam material and a preparation method thereof. Background Art

[0002] When heated, thermosetting polymers undergo a cross-linking reaction, forming a three-dimensional network structure. Traditional processing methods for thermosetting polymers typically use external heating methods, such as hot pressing and injection molding, to heat the thermosetting polymer through conduction, convection, or radiation. Traditional heating methods have significant temperature gradients, resulting in uneven heating of the thermosetting polymer. During the heating and foaming process of thermosetting polymers, the presence of temperature gradients can also lead to poor cell uniformity in the thermosetting polymer. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a thermoplastic resin composite foam material and a preparation method thereof. The preparation method provided by the present invention can improve the uniformity of the pore structure of the foam material.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing a thermoplastic resin composite foam material, comprising the following steps:

[0006] Melting and blending a thermoplastic resin, an acrylate modifier, a lubricant, a heat stabilizer, a thermosetting polymer, an auxiliary plasticizer, and an auxiliary curing agent to obtain a polymer matrix;

[0007] hot-pressing the polymer substrate to obtain a regular sheet-like polymer substrate;

[0008] saturating the regular sheet-like polymer substrate in high-pressure gas and then releasing the pressure to obtain a saturated substrate;

[0009] placing the saturated substrate in water and performing microwave heating to obtain a thermoplastic resin composite foam material;

[0010] The pressure of the high-pressure gas is 5-15 MPa.

[0011] Preferably, the thermoplastic resin includes one or more of polyvinyl chloride resin, polyethylene resin, polystyrene resin and polymethyl methacrylate resin.

[0012] Preferably, the acrylic ester modifier is polymethyl methacrylate.

[0013] Preferably, the thermosetting polymer includes a thermosetting polymer monomer or a thermosetting polymer oligomer.

[0014] Preferably, the heat stabilizer includes one or more of epoxidized soybean oil, epoxidized linseed oil and liquid calcium zinc stabilizer.

[0015] Preferably, the auxiliary plasticizer is one or more of phthalate esters, triesters of phosphate, epoxy soybean oil, epoxy sunflower oil and epoxy ether ketone.

[0016] Preferably, the auxiliary curing agent is one or more of methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, diphenyl ether tetracarboxylic dianhydride and trimellitic anhydride.

[0017] Preferably, the microwave power of the microwave heating is 200 W and the time is 5 min, or the microwave power of the microwave heating is 600 W and the time is 2 min.

[0018] Preferably, the melt blending temperature is 120-170° C., and the time is 3-10 minutes.

[0019] The present invention also provides a thermoplastic resin composite foam material prepared by the preparation method of the above technical solution, wherein the density of the thermoplastic resin composite foam material is 30 to 50 kg / m 3 The average cell size is 35-45 μm, and the cell wall thickness is 0.3-0.4 μm.

[0020] The present invention provides a method for preparing a thermoplastic resin composite foam material, comprising the following steps: melt-blending a thermoplastic resin, an acrylate modifier, a lubricant, a thermal stabilizer, a thermosetting polymer, an auxiliary plasticizer, and an auxiliary curing agent to obtain a polymer substrate; hot-pressing the polymer substrate to obtain a regular sheet-like polymer substrate; saturating the regular sheet-like polymer substrate in a high-pressure gas, then releasing the pressure to obtain a saturated substrate; placing the saturated substrate in water and heating it with a microwave to obtain a thermoplastic resin composite foam material; the pressure of the high-pressure gas is 5 to 15 MPa. In the present invention, melt mixing is the first step in processing the blended material, and the thermoplastic resin is uniformly mixed with the thermosetting polymer while being formed. The high-pressure gas saturation saturates the foaming agent (i.e., high-pressure gas) into the blended material. Microwave heating foaming and curing solidify the foam while heating it, ensuring that the pore structure of the foamed material is maintained. Melt mixing, high-pressure gas saturation, microwave heating, foaming, and curing are interrelated, greatly improving the fusion between the components from preparation to foaming and curing, increasing the glass transition temperature and uniformity of the foaming material's pore structure, and simplifying the foaming material production process. Due to its high melt strength, thermoplastic resins require higher temperatures for foaming. In the present invention, the thermoplastic resin does not undergo a high-temperature gas saturation process, and thus does not experience thermal decomposition problems. The high-temperature time experienced (the gas saturation process during the polymer foaming process) is greatly shortened, significantly reducing the thermal stability requirements of the system. The present invention uses high-pressure gas as a foaming agent, eliminating chemical foaming agent decomposition residues, and the process and product are environmentally friendly and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cell morphology diagram of the polyvinyl chloride composite foam material prepared in Comparative Example 1;

[0022] Figure 2 This is a pore morphology diagram of the polyvinyl chloride composite foam material prepared in Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a thermoplastic resin composite foam material, comprising the following steps:

[0024] Melting and blending a thermoplastic resin, an acrylate modifier, a lubricant, a heat stabilizer, a thermosetting polymer, an auxiliary plasticizer, and an auxiliary curing agent to obtain a polymer matrix;

[0025] hot-pressing the polymer substrate to obtain a regular sheet-like polymer substrate;

[0026] saturating the regular sheet-like polymer substrate in high-pressure gas and then releasing the pressure to obtain a saturated substrate;

[0027] placing the saturated substrate in water and performing microwave heating to obtain a thermoplastic resin composite foam material;

[0028] The pressure of the high-pressure gas is 5-15 MPa.

[0029] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used, and commercially available products known to those skilled in the art can be used.

[0030] The invention melt-blends thermoplastic resin, acrylic ester modifier, lubricant, heat stabilizer, thermosetting polymer, auxiliary plasticizer and auxiliary curing agent to obtain polymer substrate.

[0031] As an embodiment, the thermoplastic resin includes one or more of polyvinyl chloride resin, polyethylene resin, polystyrene resin and polymethyl methacrylate resin, and in a specific embodiment, the thermoplastic resin is polyvinyl chloride resin.

[0032] In one embodiment, the acrylate modifier is polymethyl methacrylate; the mass ratio of the polyvinyl chloride resin to the acrylate modifier is 100:1 to 50, and in a specific embodiment, 100:5. The acrylate modifier can improve melt elasticity, enhance cell wall strength, and prevent collapse. The addition of the acrylate modifier makes the cell structure of the foam material more uniform and complete.

[0033] In one embodiment, the lubricant is one or more of stearic acid, glyceryl stearate, calcium stearate, and polyethylene wax, with calcium stearate and polyethylene wax being specific examples. The mass ratio of the thermoplastic resin to the lubricant is 100:0.5-5, with a specific example being 100:1.2. The addition of the lubricant improves the uniformity of the polymer substrate and reduces adhesion to the mold, thereby producing a uniform foam material. The lubricant used in the present invention significantly reduces adhesion of the blended materials during melt blending and hot press molding.

[0034] In one embodiment, the heat stabilizer includes one or more of epoxidized soybean oil, epoxidized linseed oil, and a liquid calcium-zinc stabilizer, with the specific embodiment being a liquid calcium-zinc stabilizer. The liquid calcium-zinc stabilizer is manufactured by Sinopharm Chemical Reagent Co., Ltd., model number S25284-1kg. The mass ratio of the thermoplastic resin to the heat stabilizer is 100:1 to 5, with the specific embodiment being 100:5. The heat stabilizer has no effect on the glass transition temperature and uniformity of the foamed material's cellular structure, and its use can reduce decomposition during hot pressing. The heat stabilizer used in the present invention exhibits excellent thermal stabilization.

[0035] As one embodiment, the thermosetting polymer includes a thermosetting polymer monomer or a thermosetting polymer oligomer. Another embodiment is one or more of diphenylmethane-4,4'-diisocyanate, polymethylene polyphenyl polyisocyanate, and bisphenol A epoxy resin, and in a specific embodiment, polymethylene polyphenyl polyisocyanate. The mass ratio of the thermoplastic resin to the thermosetting polymer is 100:30 to 100, and in a specific embodiment, it is 100:50. The thermosetting polymer monomer or oligomer reduces the glass transition temperature of the foamed material obtained by melt blending, and the glass transition temperature of the foamed material is related to the content of the thermosetting polymer monomer or oligomer. The present invention has no special limitation on the degree of polymerization or weight-average molecular weight of the thermosetting polymer oligomer, and the degree of polymerization or weight-average molecular weight well known in the art can be used.

[0036] As an embodiment, the auxiliary plasticizer is one or more of phthalate, triester phosphate, epoxy soybean oil, epoxy sunflower oil and epoxy ether ketone, and in a specific embodiment, it is phthalate; the phthalate is dioctyl phthalate; the mass ratio of the thermoplastic resin to the auxiliary plasticizer is 100:2 to 10, and in a specific embodiment, it is 100:6. Auxiliary plasticizers can improve the processability of the foam material and reduce the glass transition temperature of the foam material; the uniformity of the polymer matrix obtained by melt blending during the processing determines the uniformity of the pore structure. The several auxiliary plasticizers used in the present invention have a good speed-increasing effect, and a uniform foam material cannot be obtained without the use of auxiliary plasticizers.

[0037] As an embodiment, the auxiliary curing agent is one or more of methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, diphenyl ether tetracarboxylic dianhydride and trimellitic anhydride, and in a specific embodiment, it is methylhexahydrophthalic anhydride; the mass ratio of the thermoplastic resin to the auxiliary curing agent is 100:5-50, and in a specific embodiment, it is 100:20. Different types of auxiliary curing agents have different curing reaction rates, different final cross-linking structures, and different glass transition temperatures of the foamed materials. The several auxiliary curing agents used in the present invention have good reactivity with isocyanate. Failure to use an auxiliary curing agent will result in slow foam curing and unstable pore structure.

[0038] In one embodiment, prior to melt blending, the method further includes premixing the thermoplastic resin, acrylic modifier, lubricant, thermal stabilizer, thermosetting polymer, auxiliary plasticizer, and auxiliary curing agent to obtain a paste; the premixing is performed at room temperature. The present invention does not specifically limit the premixing process; it only requires that the materials be uniformly mixed.

[0039] As an embodiment, the melt blending temperature is 120-170°C, specifically 150°C, and the time is 3-10 minutes, specifically 3-5 minutes. The melt blending temperature and time used in the present invention can improve the uniformity of the blending system, thereby improving the uniformity of the pore structure, avoiding the decomposition of the thermoplastic resin due to excessively high temperature and excessive time, which affects the uniformity of the final foam, and has no effect on the glass transition temperature of the foaming material.

[0040] After obtaining the polymer substrate, the present invention performs heat pressing on the polymer substrate to obtain a regular sheet-shaped polymer substrate.

[0041] As an embodiment, the hot pressing temperature is 150-180°C, specifically 150°C in a specific embodiment, and the time is 3-10 minutes, specifically 5 minutes in a specific embodiment; the equipment used for the hot pressing is a hot press; the specific process of the hot pressing is: placing the polymer substrate in a mold for hot pressing, and then demolding to obtain a regular sheet-like polymer substrate.

[0042] After obtaining the regular sheet-like polymer substrate, the present invention saturates the regular sheet-like polymer substrate in high-pressure gas and then releases the pressure to obtain a saturated substrate.

[0043] As an embodiment, the high-pressure gas is carbon dioxide or nitrogen, specifically carbon dioxide; the pressure of the high-pressure gas is 5-15 MPa, specifically 10-15 MPa; the saturation time is 30-120 min, specifically 30-60 min; and the saturation temperature is 20-80°C, specifically 60°C. The high-pressure gas has no effect on the glass transition temperature of the foamed material and the uniformity of the pore structure. The high-pressure gas acts as a foaming agent for the foamed material and escapes after foaming, leaving no residue in the foam. Carbon dioxide and nitrogen are chemically stable and environmentally safe. The saturation pressure and time of the high-pressure gas only affect the uniformity of the gas in the polymer matrix; too short a saturation time can lead to uneven saturation. It has no effect on the glass transition temperature of the final foamed material. The uniformity of the pore structure depends on whether the gas saturation process is uniform and the uniformity of the polymer matrix itself.

[0044] As an embodiment, the process of saturating the polymer substrate in high-pressure gas is as follows: placing the polymer substrate in an autoclave, introducing high-pressure gas, and then insulating the autoclave in an oil bath; the temperature of the oil bath is 20 to 80° C., and in a specific embodiment, 60° C.

[0045] In one embodiment, the pressure relief rate is ≤ 0.05 MPa / s, and in a specific embodiment, it is 0.05 MPa / s. The pressure relief is performed by uniformly reducing the pressure to normal pressure over 2 to 5 minutes, and in a specific embodiment, it is performed over 3 minutes. The present invention sets the pressure relief rate within this range to avoid foaming of the polymer substrate due to excessively high pressure relief rates.

[0046] After obtaining the saturated substrate, the present invention places the saturated substrate in water and performs microwave heating to obtain a thermoplastic resin composite foam material.

[0047] As an embodiment, the temperature of the water is room temperature; the volume ratio of the saturated substrate to water is 1:50 to 200, and in a specific embodiment is 1:100; the microwave power of the microwave heating is 200W and the time is 5 minutes, or the microwave power of the microwave heating is 600W and the time is 2 minutes; the equipment used for the microwave heating is a microwave oven.

[0048] Water, as an absorbing medium, heats up rapidly under the action of microwaves, generating a large amount of water vapor in a short period of time, which promotes the expansion of the foam. Compared with Comparative Example 1, which involved placing the foam in 90°C hot water, letting it rest for 30 minutes, and then curing it in 70°C water vapor for 1 hour, this method improves efficiency and simplifies the process.

[0049] Microwave heating uses electromagnetic waves to directly act on polar molecules within the material (such as moisture and resin matrix), triggering molecular vibration and frictional heat generation, achieving rapid and uniform temperature rise within the material, with energy utilization rates reaching 60-80%, while traditional heat conduction can only utilize 20-30%. Microwave heating can achieve a heating rate 5-10 times that of traditional methods (e.g., from room temperature to 200°C in just seconds to minutes), accelerate cross-linking reactions, and shorten curing time by more than 50%. Through its efficient and uniform heating mechanism, microwave heating has achieved breakthroughs in speed, performance, and sustainability in thermosetting polymer molding, making it particularly suitable for applications with high added value, complex structures, and high performance requirements.

[0050] Microwave foaming can improve the glass transition temperature and uniformity of the cell structure. The present invention uses microwaves to rapidly and uniformly heat a thermosetting polymer system to achieve foaming and curing. The power and duration of microwave heating determine the density and strength of the foam. The microwave power and duration used in the present invention can increase the glass transition temperature of the foamed material.

[0051] In the preparation method of the present invention, the melt blending time is short, the foaming agent is impregnated at room temperature, and the microwave is used for heating and foaming, so the overall energy consumption of the process is greatly reduced.

[0052] The present invention also provides a thermoplastic resin composite foam material prepared by the preparation method described in the above technical solution.

[0053] As an embodiment, the density of the thermoplastic resin composite foam material is 30 to 50 kg / m 3 , in the specific embodiment, it is 31kg / m 3 or 36kg / m 3 The average cell size is 35-45 μm, specifically 42 μm or 38 μm in the embodiment, and the cell wall thickness is 0.3-0.4 μm, specifically 0.32 μm or 0.35 μm in the embodiment.

[0054] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention, but they should not be understood as limiting the scope of protection of the present invention.

[0055] Comparative Example 1

[0056] 50 g of polyvinyl chloride resin, 3 g of phthalate, 2.5 g of liquid calcium zinc stabilizer (Sinopharm Chemical Reagent Co., Ltd., S25284-1 kg), 2.5 g of polymethyl methacrylate, 0.3 g of calcium stearate, 0.3 g of PE wax, 25 g of polymethylene polyphenyl polyisocyanate, and 10 g of methyl hexahydrophthalic anhydride were pre-mixed at room temperature to obtain a paste, which was melt-mixed at 150 ° C for 3 min. The obtained polymer substrate was placed in a 20 × 20 × 2 mm mold. , hot-pressed at 150°C for 5 minutes in a hot press, and then demolded to obtain a regular sheet-like polymer substrate; the regular sheet-like polymer substrate was placed in an autoclave, and CO2 was introduced to a pressure of 15 MPa. The autoclave was kept warm by a 60°C oil bath. After saturation for 60 minutes, the pressure was slowly reduced to normal pressure at a pressure relief rate of 0.05 MPa / s within 3 minutes. The saturated substrate was taken out and placed in 90°C hot water, allowed to stand for 30 minutes, and cured in a 70°C water vapor environment for 1 hour to obtain a polyvinyl chloride composite foam material.

[0057] Example 1

[0058] 50 g of polyvinyl chloride resin, 3 g of phthalate, 2.5 g of liquid calcium zinc stabilizer (Sinopharm Chemical Reagent Co., Ltd., S25284-1 kg), 2.5 g of polymethyl methacrylate, 0.3 g of calcium stearate, 0.3 g of PE wax, 25 g of polymethylene polyphenyl polyisocyanate, and 10 g of methyl hexahydrophthalic anhydride were pre-mixed at room temperature to obtain a paste, which was melt-mixed at 150 ° C for 3 min. The obtained polymer substrate was placed in a 20 × 20 × 2 mm mold and pressed under a hot press. After hot pressing at 150°C for 5 minutes, demolding was carried out to obtain a regular flaky polymer substrate; the regular flaky polymer substrate was placed in an autoclave, CO2 was introduced to a pressure of 15 MPa, the autoclave was kept warm by a 60°C oil bath, and after saturation for 60 minutes, the pressure was slowly reduced to normal pressure at a pressure release rate of 0.05 MPa / s within 3 minutes, the saturated substrate was taken out and placed in room temperature water (the volume ratio of the saturated substrate to water was 1:100) and placed in a microwave oven, and heated at 200 W for 5 minutes to obtain a polyvinyl chloride composite foam material.

[0059] Comparative Example 2

[0060] The difference from Example 1 is that the saturated substrate is placed in water at room temperature and placed in a microwave oven, and heated at 400 W for 2 minutes to obtain a polyvinyl chloride composite foam material.

[0061] Example 2

[0062] The difference from Example 1 is that the saturated substrate is placed in water at room temperature and placed in a microwave oven, and heated at 600 W for 2 minutes to obtain a polyvinyl chloride composite foam material.

[0063] Comparative Example 3

[0064] The difference from Example 1 is that the saturated substrate is placed in water at room temperature and placed in a microwave oven, and heated at 1000 W for 2 minutes to obtain a polyvinyl chloride composite foam material.

[0065] Performance Testing

[0066] The polyvinyl chloride composite foam materials prepared in the comparative example and the embodiment were photographed using a scanning electron microscope (SEM, Nove NanoSEM450), and the average cell diameter was calculated using image processing software (Image Pro Plus). The density of the polyvinyl chloride composite foam material was measured using the drainage method. The results are shown in Table 1.

[0067] Table 1 Cell characteristics of polyvinyl chloride composite foam materials

[0068] Serial number Average cell size (μm) <![CDATA[Density (kg / m 3 )]]> Hole wall thickness (μm) Comparative Example 1 30 60 0.87 Example 1 42 31 0.32 Comparative Example 2 32 70 0.89 Example 2 38 36 0.35 Comparative Example 3 17 142 1.02

[0069] As shown in Table 1, during microwave heating, power and time determine the material's expansion ratio. Higher power results in faster system temperature rise, leading to more intense cell growth caused by thermodynamic instability. The air pressure within the cells decreases, and crosslinking of the foam also proceeds simultaneously. The appropriate power and time combination allows the foam to solidify when it reaches maximum expansion. For example, in Example 1, heating was performed at 200W for 5 minutes, and in Example 2, heating was performed at 600W for 2 minutes. However, when the microwave power was increased to 1000W, the sample heated up too quickly, causing the CO2 saturated in the sample to diffuse rapidly. At this point, the foam did not solidify sufficiently to maintain the cells. Consequently, the foam cell size was significantly reduced, the cell wall thickness increased, and the foam density increased. In Comparative Example 2, heating was performed at 400W for 2 minutes, but the sample failed to fully expand. In Comparative Example 4, heating was performed at 1000W for 2 minutes, resulting in higher system temperatures and delayed sample solidification, leading to foam shrinkage. A uniform cell structure is difficult to achieve when the foam density is low. The method of the present invention simultaneously heats and solidifies, improving efficiency while maintaining cell uniformity.

[0070] In summary, compared with the comparative example, Examples 1-2 significantly reduced the foaming time and did not require a subsequent curing process.

[0071] Figure 1 The SEM image of the pore morphology of the polyvinyl chloride composite foam material prepared in Comparative Example 1 is shown. Figure 1 As shown, in Comparative Example 1, the polyvinyl chloride composite foam material prepared by steam curing has thick cell walls and insufficient foam growth.

[0072] Figure 2 The SEM image of the cell morphology of the polyvinyl chloride composite foam material prepared in Example 1 is shown in FIG. Figure 2 As shown, the polyvinyl chloride composite foam material obtained by microwave rapid heating foaming has thin pore walls, fully grown pores, and greatly reduced foam density.

[0073] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a thermoplastic resin composite foam material, characterized in that: The following steps are involved: Melting and blending a thermoplastic resin, an acrylate modifier, a lubricant, a heat stabilizer, a thermosetting polymer, an auxiliary plasticizer, and an auxiliary curing agent to obtain a polymer matrix; hot-pressing the polymer substrate to obtain a regular sheet-like polymer substrate; saturating the regular sheet-like polymer substrate in high-pressure gas and then releasing the pressure to obtain a saturated substrate; placing the saturated substrate in water and performing microwave heating to obtain a thermoplastic resin composite foam material; The pressure of the high-pressure gas is 5-15 MPa.

2. The preparation method according to claim 1, characterized in that The thermoplastic resin includes one or more of polyvinyl chloride resin, polyethylene resin, polystyrene resin and polymethyl methacrylate resin.

3. The preparation method according to claim 1, characterized in that The acrylic ester modifier is polymethyl methacrylate.

4. The preparation method according to claim 1, characterized in that The thermosetting polymer includes a thermosetting polymer monomer or a thermosetting polymer oligomer.

5. The preparation method according to claim 1, characterized in that The heat stabilizer includes one or more of epoxidized soybean oil, epoxidized linseed oil and liquid calcium zinc stabilizer.

6. The preparation method according to claim 1, characterized in that The auxiliary plasticizer is one or more of phthalate, triester phosphate, epoxy soybean oil, epoxy sunflower oil and epoxy ether ketone.

7. The preparation method according to claim 1, characterized in that The auxiliary curing agent is one or more of methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, diphenyl ether tetracarboxylic dianhydride and trimellitic anhydride.

8. The preparation method according to claim 1, characterized in that The microwave power of the microwave heating is 200 W and the time is 5 minutes, or the microwave power of the microwave heating is 600 W and the time is 2 minutes.

9. The preparation method according to claim 1, characterized in that The temperature of the melt blending is 120-170° C., and the time is 3-10 minutes.

10. The thermoplastic resin composite foam material prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The density of the thermoplastic resin composite foam material is 30 to 50 kg / m 3 The average cell size is 35-45 μm, and the cell wall thickness is 0.3-0.4 μm.

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