Elastic foaming material, preparation method thereof and sneaker midsole prepared from elastic foaming material

Abstract

The invention discloses an elastic foaming material, a preparation method of the elastic foaming material and a sneaker insole prepared from the elastic foaming material, and aims to solve the problems that a material used by an existing sneaker insole cannot give consideration to high rebound rate and better shock absorption and buffering performance and is low in compression set. The elastic foaming material is prepared from the following raw materials in parts by weight: 40 to 45 parts of thermoplastic polyester elastomer, 20 to 25 parts of hydrogenated styrene-butadiene block copolymer, 20 to 25 parts of bio-based degradable polyester rubber, 10 to 15 parts of metallocene polyethylene, 3 to 5 parts of wear-resistant agent, 0.5 to 0.8 part of stearic acid, 1 to 2 parts of zinc oxide whisker, 3 to 5 parts of filler, 0.6 to 0.8 part of cross-linking agent, 2 to 3 parts of azodicarbonamide and 3 to 5 parts of expanded microspheres.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to an elastic foam material, a preparation method thereof, and a sports shoe midsole made therefrom. Background Art

[0002] Cross-country running is a very popular method of physical exercise. The sports shoes used for cross-country running mainly provide rebound, shock absorption and cushioning, durability, stability, motion control and other functions.

[0003] Today's soles are mainly composed of three parts: the outsole, the midsole and the insole. Among them, the midsole is the focus of the entire sole structure design. It is an important component to ensure that the entire shoe has good rebound, shock absorption and cushioning, stability and energy return, which will directly affect the functionality and comfort of the shoe.

[0004] Generally speaking, ideal athletic shoes require lightweight, low g-value, low compression set, and high rebound. A lower g-value indicates better shock absorption and cushioning performance in the midsole, while a higher rebound indicates better energy return.

[0005] However, the midsole of typical sports shoes often lacks both shock absorption and rebound performance. The higher the energy return rebound rate, the worse the shock absorption and cushioning performance. Therefore, high-elasticity midsole materials often fail to provide adequate shock absorption and cushioning performance.

[0006] In addition, the midsole of the shoe material must have a low permanent deformation rate to have better wear resistance and durability. The majority of the midsole materials used in sports shoes currently on the market are hydrogenated styrene-butadiene block copolymer (ethylene-vinyl acetate, EVA), polyethylene (polyethylene, PE), thermoplastic polyurethane (thermoplasticurethane, TPU) foam materials, etc. However, the above materials have at least the following disadvantages: (1) The density of EVA foam material is high (generally between 0.2-0.3g / cm 3 ), high compression set (generally greater than 50%), and low rebound rate. The rebound rate of general EVA foam materials and their mixtures is about 40%. (2) TPU foam materials have a high density, so the midsoles of sports shoes made of TPU foam materials are heavy and hard, resulting in insufficient shock absorption and cushioning performance of the sports shoes.

[0007] Therefore, there is a need for a foam material that can meet the requirements of sports shoes for light weight, low compression permanent deformation rate, high rebound rate, and good shock absorption and cushioning performance as the midsole material of sports shoes. Summary of the Invention

[0008] The embodiments of the present application provide an elastic foam material to solve the problem that the materials used in the midsoles of existing sports shoes cannot achieve both high rebound rate and good shock absorption and cushioning, as well as low compression distortion.

[0009] The embodiment of the present application also provides a method for preparing an elastic foam material to solve the problem that the materials used in the midsoles of existing sports shoes cannot achieve both high rebound rate and good shock absorption and cushioning, as well as low compression distortion.

[0010] The embodiment of the present application also provides a sports shoe midsole made of the above-mentioned elastic foam material, which is used to solve the problem that the materials used in the existing sports shoe midsoles cannot achieve both high rebound rate and good shock absorption and cushioning, as well as low compression distortion.

[0011] The embodiments of this application adopt the following technical solutions: An elastic foam material comprises the following raw materials in parts by weight: 40-45 parts of thermoplastic polyester elastomer; 20-25 parts of hydrogenated styrene-butadiene block copolymer; 20-25 parts of biodegradable polyester rubber; 10-15 parts of metallocene polyethylene; 3~5 parts of anti-wear agent; 0.5-0.8 parts of stearic acid; 1-2 parts of zinc oxide whiskers; 3~5 parts of filler; 0.6~0.8 parts of cross-linking agent; 2-3 parts of azodicarbonamide; 3~5 parts of expanded microspheres.

[0012] Optionally, the vinyl acetate content of the hydrogenated styrene-butadiene block copolymer is in the range of 18% to 40%.

[0013] A method for preparing an elastic foam material comprises the following steps: mixing a thermoplastic polyester elastomer, a hydrogenated styrene-butadiene block copolymer, a bio-based degradable polyester rubber, metallocene polyethylene, an anti-wear agent, stearic acid, zinc oxide whiskers, a filler, a crosslinking agent, azodicarbonamide and expanded microspheres in a blender to obtain a mixture; adding the mixture to a twin-screw underwater pelletizer for extrusion and pelletization; adding the pelletized material to a hot air dryer for dehydration and drying to obtain semi-finished hot-melt rubber pellets; irradiating the semi-finished hot-melt rubber pellets with a high-energy accelerated electron beam to obtain hot-melt rubber pellets; and adding the hot-melt rubber pellets to a small foaming mold for chemical foaming to obtain the elastic foam material.

[0014] In one embodiment, the mixed material is obtained by the following steps: a thermoplastic polyester elastomer, a hydrogenated styrene-butadiene block copolymer, a bio-based degradable polyester rubber, a metallocene polyethylene, an anti-wear agent, stearic acid, zinc oxide whiskers, a filler and a cross-linking agent are mixed for the first time in a blender to obtain a primary mixed material; azodicarbonamide and expanded microspheres are added to the primary mixed material, and mixed for a second time in a blender to obtain a mixed material.

[0015] In one embodiment, the primary mixed material can be obtained by the following steps: adding a thermoplastic polyester elastomer, a hydrogenated styrene-butadiene block copolymer, a bio-based degradable polyester rubber, a metallocene polyethylene, an anti-wear agent, stearic acid, zinc oxide whiskers, a filler and a cross-linking agent into a blender, heating the blender to 150° C. to 200° C.; stirring the heated blender at a speed of 60 to 100 r / min for 3 to 5 minutes to obtain the primary mixed material.

[0016] In one embodiment, the mixed material is obtained by the following steps: adding azodicarbonamide, expanded microspheres and the primary mixed material into a blender, heating the blender to 120° C. to 150° C.; stirring the heated blender at a speed of 60 to 100 r / min for 3 to 5 minutes to obtain the mixed material.

[0017] In one embodiment, extrusion granulation can be performed by the following steps, including: adding the mixed material into a twin-screw underwater granulator through a feeding hopper; extruding and granulating the twin-screw underwater granulator at a speed of 200-400 r / min, a barrel temperature of 120-200° C., and a head temperature of 150-180° C.

[0018] In one embodiment, semi-finished hot melt rubber pellets can be obtained by the following steps: adding the granules into a hot air dryer, dehydrating and drying at a temperature of 70-90° C. until the moisture content of the granules is below 0.2%, thereby obtaining semi-finished hot melt rubber pellets.

[0019] In one embodiment, the hot melt adhesive particles can be obtained by the following steps: the semi-finished hot melt adhesive particles are irradiated with a high-energy accelerated electron beam, wherein the energy of the high-energy accelerated electron beam is 1.0-2.0 eV and the irradiation time is 30-60 seconds to obtain hot melt adhesive particles.

[0020] In one embodiment, the elastic foam material can be obtained by the following steps: adding the hot melt adhesive particles into a small foaming mold, 0 C for 20 to 30 minutes to obtain the elastic foaming material.

[0021] A method for preparing a sports shoe midsole using the above-mentioned elastic foam material comprises: adding the elastic foam material to a midsole mold, injecting carbon dioxide into the midsole mold, pressurizing and heating the midsole mold to a supercritical state, and physically foaming the elastic foam material in the midsole mold to obtain a sports shoe midsole made of the elastic foam material.

[0022] At least one of the above technical solutions adopted in the embodiments of the present application can achieve the following beneficial effects: The elastic foam material provided in the embodiment of the present application is prepared from the following components in parts by weight: 40-45 parts of thermoplastic polyester elastomer, 20-25 parts of hydrogenated styrene-butadiene block copolymer, 20-25 parts of biodegradable polyester rubber, 10-15 parts of metallocene polyethylene, 3-5 parts of wear-resistant agent, 0.5-0.8 parts of stearic acid, 1-2 parts of zinc oxide whiskers, 3-5 parts of filler, 0.6-0.8 parts of cross-linking agent, 2-3 parts of azodicarbonamide, and 3-5 parts of expanded microspheres. Compared to traditional elastic foam materials made from a single raw material (such as EVA, PE, or TPU), the elastic foam material prepared using the methods provided in the embodiments of this application, due to the inclusion of thermoplastic polyester elastomer in the raw materials and the use of a three-foaming system of chemical foaming, expanded microsphere foaming, and physical foaming during the preparation process, as well as two crosslinking methods, high-energy electron beam irradiation and chemical crosslinking, results in the prepared material having better physical properties and stability. Furthermore, the prepared elastic foam material exhibits good elasticity in the soft segment and improved strength and processing performance in the hard segment. Athletic shoe midsoles made from this elastic foam material can significantly improve the mechanical properties, rebound performance, and shock absorption and cushioning performance of the sole, while reducing the compression set rate of the sole. Furthermore, the elastic foam material provides better protection for the wearer during wear and increases product durability. Furthermore, the midsole prepared using the methods provided in this solution fully retains the biodegradability of polyester rubber, making the product more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 A schematic diagram of a specific process of a method for preparing an elastic foam material provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0026] Several specific examples of producing elastic foam materials according to this embodiment are described below. Unless otherwise specified, "parts" in the description refer to parts by weight.

[0027] Example 1 This embodiment discloses an elastic foam material, which comprises the following raw material components in parts by mass: Thermoplastic polyester elastomer (TPEE) 40-45 parts; 20-25 parts of hydrogenated styrene-butadiene block copolymer (SEBS); 20-25 parts of biodegradable polyester rubber; 10-15 parts of metallocene polyethylene; 3~5 parts of anti-wear agent; 0.5-0.8 parts of stearic acid; 1-2 parts of zinc oxide whiskers; 3~5 parts of filler; 0.6~0.8 parts of cross-linking agent; 2-3 parts of azodicarbonamide; 3~5 parts of expanded microspheres.

[0028] The vinyl acetate content of the hydrogenated styrene-butadiene block copolymer ranges from 18% to 40%, and the melt index ranges from 2.0 to 8.0 g / 10 min.

[0029] In one embodiment, the expanded microspheres used in the examples of this application are thermoplastic hollow polymer microspheres composed of a thermoplastic polymer shell (e.g., acrylate or polyvinylidene chloride (PVDC)) enclosed in a low-boiling-point hydrocarbon gas (e.g., isobutane, pentane, etc.). These hollow spheres have an average diameter ranging from 10 to 50 µm and a true density of 1000 kg / m³ to 1300 kg / m³. When heated, the gas pressure within the shell increases and the thermoplastic shell softens, significantly increasing the volume of the expanded microspheres. Using expanded microspheres for foaming results in uniform pores, is environmentally friendly, and leaves no decomposition residue, making them suitable for high-precision foaming.

[0030] The elastic foam material is prepared according to the above raw material formula, and the preparation steps are detailed as follows.

[0031] Step 11, add 40 parts of thermoplastic polyester elastomer (TPEE), 20 parts of hydrogenated styrene-butadiene block copolymer (SEBS), 20 parts of bio-based degradable polyester rubber, 10 parts of metallocene polyethylene, 3 parts of anti-wear agent, 0.5 parts of stearic acid, 1 part of zinc oxide whisker, 3 parts of filler, and 0.6 parts of cross-linking agent into a blender, heat the blender to 150° C., and stir the blender at 80 r / min for 5 minutes to obtain a primary mixed material.

[0032] Step 12: add 2 parts of azodicarbonamide and 3 parts of expanded microspheres to the primary mixed material obtained by performing the primary mixing in step 11, heat the mixer to 150° C., and stir the heated mixer at 80 r / min for 5 minutes for a second mixing to obtain a mixed material.

[0033] Step 13, adding the mixture obtained by performing step 12 into a twin-screw underwater pelletizer for extrusion pelletization; In this embodiment, the granules may be spherical or round particles with a diameter of 3 to 5 mm.

[0034] Specifically, the mixed material can be added into a twin-screw underwater granulator through a feeding hopper, and the twin-screw underwater granulator extrudes and granulates at a rotation speed of 300 r / min, a barrel temperature of 160° C., and a head temperature of 180° C.

[0035] Step 14: Add the granules obtained by executing step 13 into a hot air dryer for dehydration and drying to obtain semi-finished hot melt rubber particles.

[0036] Specifically, the granules are added into a hot air dryer for dehydration and drying at a temperature of 70-90° C. until the moisture content of the granules is below 0.2%, thereby obtaining semi-finished hot-melt rubber granules.

[0037] Step 15: irradiate the semi-finished hot-melt adhesive particles obtained by executing step 14 with a high-energy accelerated electron beam to obtain hot-melt adhesive particles.

[0038] Specifically, in the embodiment of the present application, a high-energy accelerated electron beam with an energy of 1.0 to 2.0 eV can be used to irradiate the semi-finished hot-melt adhesive particles for 30 seconds to 1 minute, so that the high-energy electron beam penetrates the surface of the material and triggers a cross-linking reaction, thereby achieving the purpose of modifying the semi-finished hot-melt adhesive particles.

[0039] Step 16: Add the hot melt rubber particles processed in step 15 into a small foaming mold, and perform chemical foaming at a temperature of 190° C. for 20 to 30 minutes to obtain an elastic foam material.

[0040] In one embodiment, the embodiment of the present application also provides a method for preparing a sports shoe midsole using the above-mentioned elastic foaming material. The preparation method includes: after completing chemical foaming, adding the elastic foaming material obtained in step 16 to a midsole mold, injecting carbon dioxide into the midsole mold, and pressurizing and heating the midsole mold to a supercritical state, physically foaming the elastic foaming material in the midsole mold, and finally obtaining a sports shoe midsole made of the elastic foaming material.

[0041] Example 2 This embodiment discloses a method for preparing an elastic foam material, and the preparation steps are described in detail as follows.

[0042] Step 21, add 42 parts of thermoplastic polyester elastomer (TPEE), 22 parts of hydrogenated styrene-butadiene block copolymer (SEBS), 23 parts of bio-based degradable polyester rubber, 12 parts of metallocene polyethylene, 4 parts of anti-wear agent, 0.6 parts of stearic acid, 1.5 parts of zinc oxide whisker, 4 parts of filler, and 0.7 parts of cross-linking agent into a blender, heat the blender to 150° C., and stir the heated blender at 80 r / min for 5 minutes to obtain a primary mixed material.

[0043] Step 22: add 2.5 parts of azodicarbonamide and 4 parts of expanded microspheres to the primary mixed material obtained by performing the primary mixing in step 21, heat the mixer to 150° C., and stir the heated mixer at 80 r / min for 5 minutes for a second mixing to obtain a mixed material.

[0044] Step 23, adding the mixture obtained by executing step 22 into a twin-screw underwater pelletizer for extrusion pelletization; In this embodiment, the granules may be spherical or round particles with a diameter of 3 to 5 mm.

[0045] Specifically, the mixed material can be added into a twin-screw underwater granulator through a feeding hopper, and the twin-screw underwater granulator extrudes and granulates at a rotation speed of 300 r / min, a barrel temperature of 160° C., and a head temperature of 180° C.

[0046] In step 24, the granules obtained by executing step 23 are added to a hot air dryer for dehydration and drying to obtain semi-finished hot melt rubber particles.

[0047] Specifically, the granules are added into a hot air dryer for dehydration and drying at a temperature of 70-90° C. until the moisture content of the granules is below 0.2%, thereby obtaining semi-finished hot-melt rubber granules.

[0048] In step 25, the semi-finished hot-melt adhesive particles obtained by executing step 24 are irradiated with a high-energy accelerated electron beam to obtain hot-melt adhesive particles.

[0049] Specifically, in the embodiment of the present application, a high-energy accelerated electron beam with an energy of 1.0 to 2.0 eV can be used to irradiate the semi-finished hot-melt adhesive particles for 30 seconds to 1 minute, so that the high-energy electron beam penetrates the surface of the material and triggers a cross-linking reaction, thereby achieving the purpose of modifying the semi-finished hot-melt adhesive particles.

[0050] Step 26: Add the hot melt rubber particles processed in step 25 into a small foaming mold, and perform chemical foaming at a temperature of 190° C. for 20 to 30 minutes to obtain an elastic foam material.

[0051] In one embodiment, the embodiment of the present application also provides a method for preparing a sports shoe midsole using the above-mentioned elastic foaming material. The preparation method includes: after completing chemical foaming, adding the elastic foaming material obtained in step 26 to a midsole mold, injecting carbon dioxide into the midsole mold, and pressurizing and heating the midsole mold to a supercritical state, physically foaming the elastic foaming material in the midsole mold, and finally obtaining a sports shoe midsole made of the elastic foaming material.

[0052] Example 3 This embodiment discloses a method for preparing an elastic foam material, and the preparation steps are described in detail as follows.

[0053] Step 31: Add 45 parts of thermoplastic polyester elastomer (TPEE), 25 parts of hydrogenated styrene-butadiene block copolymer (SEBS), 25 parts of bio-based degradable polyester rubber, 15 parts of metallocene polyethylene, 5 parts of anti-wear agent, 0.8 parts of stearic acid, 2 parts of zinc oxide whiskers, 5 parts of filler, and 0.8 parts of cross-linking agent into a blender, heat the blender to 150° C., and stir the blender at 80 r / min for 5 minutes to obtain a primary mixed material.

[0054] Step 32: add 3 parts of azodicarbonamide and 5 parts of expanded microspheres to the primary mixed material obtained by performing the primary mixing in step 31, heat the mixer to 150° C., and stir the heated mixer at 80 r / min for 5 minutes for a second mixing to obtain a mixed material.

[0055] Step 33, adding the mixture obtained by executing step 32 into a twin-screw underwater pelletizer for extrusion pelletization; In this embodiment, the granules may be spherical or round particles with a diameter of 3 to 5 mm.

[0056] Specifically, the mixed material can be added into a twin-screw underwater granulator through a feeding hopper, and the twin-screw underwater granulator extrudes and granulates at a rotation speed of 300 r / min, a barrel temperature of 160° C., and a head temperature of 180° C.

[0057] In step 34, the granules obtained by executing step 33 are added to a hot air dryer for dehydration and drying to obtain semi-finished hot melt rubber particles.

[0058] Specifically, the granules are added into a hot air dryer for dehydration and drying at a temperature of 70-90° C. until the moisture content of the granules is below 0.2%, thereby obtaining semi-finished hot-melt rubber granules.

[0059] In step 35 , the semi-finished hot-melt adhesive particles obtained by executing step 34 are irradiated with a high-energy accelerated electron beam to obtain hot-melt adhesive particles.

[0060] Specifically, in the embodiment of the present application, a high-energy accelerated electron beam with an energy of 1.0 to 2.0 eV can be used to irradiate the semi-finished hot-melt adhesive particles for 30 seconds to 1 minute, so that the high-energy electron beam penetrates the surface of the material and triggers a cross-linking reaction, thereby achieving the purpose of modifying the semi-finished hot-melt adhesive particles.

[0061] In step 36, the hot melt rubber particles processed in step 35 are added to a small foaming mold, and chemically foamed at a temperature of 190° C. for 20 to 30 minutes to obtain an elastic foam material.

[0062] In one embodiment, the embodiment of the present application also provides a method for preparing a sports shoe midsole using the above-mentioned elastic foaming material. The preparation method includes: after completing chemical foaming, adding the elastic foaming material obtained in step 26 to a midsole mold, injecting carbon dioxide into the midsole mold, and pressurizing and heating the midsole mold to a supercritical state, physically foaming the elastic foaming material in the midsole mold, and finally obtaining a sports shoe midsole made of the elastic foaming material.

[0063] Tensile testing machine, oven, yellowing testing machine, high temperature and high humidity testing machine and flexural resistance testing machine.

[0064] The standards involved in the test are as follows: Hardness: Test the hardness of sports shoe midsoles according to GB / T 3903.4-2017; Density: Test the density of sports shoe midsoles according to GB / T 533; Permanent deflection: Test the midsole of sports shoes for permanent deflection according to HG / T 2876; Rebound rate is tested according to GB / T 1681-2009; Shock absorption and cushioning are tested according to GB / T38012-2019; Tensile strength: The tensile strength of sports shoe midsoles is tested according to GB / T 21396; Tear strength: Test the tear strength of sports shoe midsole according to WJ-31; Peel strength: Test the peel strength of sports shoe midsole after combining according to GB / T 21396; Elongation: The elongation of the sports shoe midsole is tested according to TBJC-32.

[0065] Yellowing resistance is tested in accordance with the ASTM D1148-2013 rubber yellowing resistance test method. If cracks, splits, yarn breakage, pilling or other abnormal conditions appear on the surface of the sample, it will be judged as unqualified.

[0066] Table 1 is a table of performance parameters of the sports shoe midsoles prepared in Examples 1 to 3.

[0067] Table 1 Test performance parameters

[0068] The elastic foam material provided in the embodiments of the present application is prepared from the following components in parts by weight: 40-45 parts of thermoplastic polyester elastomer; 20-25 parts of hydrogenated styrene-butadiene block copolymer; 20-25 parts of biodegradable polyester rubber; 10-15 parts of metallocene polyethylene; 3-5 parts of anti-wear agent; 0.5-0.8 parts of stearic acid; 1-2 parts of zinc oxide whiskers; 3-5 parts of filler; 0.6-0.8 parts of cross-linking agent; 2-3 parts of azodicarbonamide; and 3-5 parts of expanded microspheres. Compared to traditional elastic foam materials made from a single raw material (such as EVA, PE, or TPU), the elastic foam material prepared using the methods provided in the embodiments of this application, due to the inclusion of thermoplastic polyester elastomer in the raw materials and the use of a three-foaming system of chemical foaming, expanded microsphere foaming, and physical foaming during the preparation process, as well as two crosslinking methods, high-energy electron beam irradiation and chemical crosslinking, results in the prepared material having better physical properties and stability. Furthermore, the prepared elastic foam material exhibits good elasticity in the soft segment and improved strength and processing performance in the hard segment. Athletic shoe midsoles made from this elastic foam material can significantly improve the mechanical properties, rebound performance, and shock absorption and cushioning performance of the sole, while reducing the compression set rate of the sole. Furthermore, the elastic foam material provides better protection for the wearer during wear and enhances product durability. Furthermore, the midsole prepared using the methods provided in this solution fully retains the biodegradability of polyester rubber, making the product more environmentally friendly.

[0069] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. An elastic foam material, characterized in that: The composition comprises the following raw materials in parts by weight: 40-45 parts of thermoplastic polyester elastomer; 20-25 parts of hydrogenated styrene-butadiene block copolymer; 20-25 parts of biodegradable polyester rubber; 10-15 parts of metallocene polyethylene; 3~5 parts of anti-wear agent; 0.5-0.8 parts of stearic acid; 1-2 parts of zinc oxide whiskers; 3~5 parts of filler; 0.6~0.8 parts of cross-linking agent; 2-3 parts of azodicarbonamide; 3~5 parts of expanded microspheres.

2. The elastic foam material according to claim 1, characterized in that: The vinyl acetate content of the hydrogenated styrene-butadiene block copolymer is in the range of 18% to 40%.

3. A method for preparing the elastic foam material according to claim 1, characterized in that: include: A thermoplastic polyester elastomer, a hydrogenated styrene-butadiene block copolymer, a biodegradable polyester rubber, a metallocene polyethylene, an anti-wear agent, stearic acid, zinc oxide whiskers, a filler, a cross-linking agent, azodicarbonamide, and expanded microspheres are mixed in a blender to obtain a mixed material; Adding the mixed material into a twin-screw underwater pelletizer for extrusion pelletization; The granules are added to a hot air dryer for dehydration and drying to obtain semi-finished hot melt rubber particles; irradiating the semi-finished hot-melt adhesive particles with a high-energy accelerated electron beam to obtain hot-melt adhesive particles; The hot melt rubber particles are added into a small foaming mold for chemical foaming to obtain the elastic foaming material.

4. The method according to claim 3, characterized in that The thermoplastic polyester elastomer, hydrogenated styrene-butadiene block copolymer, bio-based degradable polyester rubber, metallocene polyethylene, anti-wear agent, stearic acid, zinc oxide whisker, filler, crosslinking agent, azodicarbonamide and expanded microspheres are mixed in a blender to obtain a mixed material, which specifically includes: A thermoplastic polyester elastomer, a hydrogenated styrene-butadiene block copolymer, a biodegradable polyester rubber, a metallocene polyethylene, an anti-wear agent, stearic acid, zinc oxide whiskers, a filler, and a cross-linking agent are mixed for the first time in a blender to obtain a primary mixed material; Azodicarbonamide and expanded microspheres are added to the primary mixed material, and the mixture is kneaded for the second time in a blender to obtain a mixed material.

5. The method according to claim 3, characterized in that The thermoplastic polyester elastomer, hydrogenated styrene-butadiene block copolymer, bio-based degradable polyester rubber, metallocene polyethylene, anti-wear agent, stearic acid, zinc oxide whisker, filler and cross-linking agent are first mixed in a blender to obtain a primary mixed material, which specifically includes: Add thermoplastic polyester elastomer, hydrogenated styrene-butadiene block copolymer, bio-based degradable polyester rubber, metallocene polyethylene, anti-wear agent, stearic acid, zinc oxide whisker, filler and cross-linking agent into a blender, and heat the blender to 150° C. to 200° C.; Stir the heated mixer at a speed of 60-100 r / min for 3-5 minutes to obtain the primary mixed material.

6. The method according to claim 3, characterized in that The step of adding azodicarbonamide and expanded microspheres to the primary mixed material and performing a second mixing in a blender to obtain a mixed material specifically comprises: Add azodicarbonamide, expanded microspheres and the primary mixed material into a mixer, and heat the mixer to 120° C. to 150° C.; Stir the heated mixer at a speed of 60-100 r / min for 3-5 minutes to obtain a mixed material.

7. The method according to claim 3, characterized in that The step of adding the mixed material into a twin-screw underwater pelletizer for extrusion pelletization specifically comprises: The mixed material is added into a twin-screw underwater granulator through a feeding hopper; The twin-screw underwater pelletizer extrudes pellets at a rotation speed of 200~400r / min, a barrel temperature of 120~200℃, and a head temperature of 150~180℃.

8. The method according to claim 3, characterized in that Dehydrating and drying the granulation to obtain semi-finished hot melt rubber granules specifically comprises: The granules are added into a hot air dryer and dehydrated and dried at a temperature of 70-90° C. until the moisture content of the granules is below 0.2%, thereby obtaining the semi-finished hot melt rubber granules.

9. The method according to claim 3, characterized in that The step of irradiating the semi-finished hot melt adhesive particles with a high-energy accelerated electron beam to obtain the hot melt adhesive particles specifically includes: The semi-finished hot melt adhesive particles are irradiated with a high-energy accelerated electron beam, wherein the energy of the high-energy accelerated electron beam is 1.0-2.0 eV and the irradiation time is 30-60 seconds to obtain the hot melt adhesive particles.

10. The method according to claim 3, characterized in that The step of adding the hot melt adhesive particles into a small foaming mold for chemical foaming to obtain the elastic foam material specifically comprises: The hot melt adhesive particles are added to the small foaming mold and heated at 190 0 C for 20 to 30 minutes to obtain the elastic foaming material.

11. A method for preparing a sports shoe midsole using the elastic foam material according to claim 1, characterized in that: include: The elastic foam material is added to a midsole mold, carbon dioxide is injected into the midsole mold, and the midsole mold is pressurized and heated to a supercritical state. The elastic foam material is physically foamed in the midsole mold to obtain a sports shoe midsole made of the elastic foam material.

12. A sports shoe midsole, characterized in that: The sports shoe midsole is made from the elastic foam material according to claim 1 according to the preparation method according to claim 11.

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