Midsole foaming material and preparation method thereof

Abstract

The invention discloses an insole foaming material and a preparation method thereof, and the preparation method of the insole foaming material comprises the following steps: selecting a mixed material consisting of EVA (Ethylene Vinyl Acetate), an olefin elastomer and optional inorganic powder and a buffering agent according to the requirements of different sports scenes on the physical properties of front, middle and rear areas of an insole; adding a cross-linking agent, a cross-linking auxiliary agent and an active agent, and formulating at least one formula for each region; according to each formula, weighing, granulating and injection molding are carried out to form each area part of the insole; then carrying out vulcanization crosslinking treatment to form an integral middle bottom component; and then carrying out physical foaming treatment, and finally carrying out mold pressing and shaping to obtain a finished insole foaming material product. The invention provides an insole foaming material and a preparation method thereof, according to the preparation method, formulas with different physical characteristics are designed, a physical foaming process is adopted for synchronous foaming, the insole foaming material is prepared, and the natural gait requirements of different sports scenes are met.

Description

Technical Field

[0001] The invention relates to the technical field of sole manufacturing, and in particular to a midsole foaming material and a preparation method thereof. Background Art

[0002] With the rise of the national fitness craze, consumers have increasing functional requirements for sports shoes. Traditional sports shoes are difficult to meet the functional requirements of various areas of the foot under natural gait due to the single material. Especially when running, the ground impact force is large. If the sports shoes are not cushioning or stable enough, it may cause damage to the lower limb joints. There are currently two main solutions in the industry: glue combination solution and hardness combination solution. Although the glue combination solution can improve the problem to a certain extent, it has defects such as insufficient component connection strength, poor comfort and difficulty in accurately matching the natural gait; although the hardness combination solution solves the problem of glue connection, it is difficult to simultaneously meet the three key functional requirements of cushioning, support and rebound / energy feedback through only different hardness combinations, and the practicality and applicability are not high. Therefore, a more complete solution is needed. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology, and to provide a midsole foaming material and a preparation method thereof. The preparation method designs a formula with different physical properties, adopts a physical foaming process for synchronous foaming, and prepares a midsole foaming material to meet the natural gait requirements of different sports scenes.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] The first technical scheme relates to a method for preparing a midsole foam material, which comprises: selecting a mixed material composed of EVA, olefin elastomer, optional inorganic powder and buffer according to the requirements of different sports scenes for the physical properties of the front, middle and rear regions of the midsole, and adding a cross-linking agent, a cross-linking aid and an active agent to formulate at least one formula for each region; weighing materials for each formula respectively, and independently mixing and granulating in a mixing device to obtain granulated materials for components in each region; injection molding the granulated materials of the components in each region into components in each region of the midsole; vulcanizing and cross-linking the injection-molded components in each region to form an integral midsole component; physically foaming the integral midsole component after vulcanization and cross-linking using supercritical foaming technology to obtain the desired foaming performance; and shaping the foamed material through a molding process to obtain a finished midsole foam material.

[0006] The second technical solution is based on the first technical solution, wherein the mixed material, in parts by weight, comprises 40-50 parts of EVA, 60-50 parts of olefin elastomer, 0-15 parts of inorganic powder, and 0-20 parts of buffer.

[0007] The third technical solution is based on the second technical solution, wherein the number of formulas is three to eight according to the requirements of different sports scenarios for the physical properties of the front, middle and rear areas of the midsole.

[0008] The fourth technical solution is based on the second technical solution, wherein the VA content in EVA is greater than 18%.

[0009] The fifth technical solution is based on the second technical solution, wherein the olefin elastomer is an ethylene-octene random copolymer or an ethylene-octene regular copolymer.

[0010] The sixth technical solution is based on the second technical solution, wherein the inorganic powder is talcum powder, barium sulfate or calcium carbonate with a fineness greater than 600 mesh.

[0011] The seventh technical solution is based on the second technical solution, wherein the cross-linking agent is a peroxide cross-linking agent, which adopts one of diisopropylbenzene peroxide or 1,4-di-tert-butylperoxyisopropylbenzene.

[0012] The seventh technical solution is based on the second technical solution, wherein the active agent is one or a combination of two of stearic acid, zinc stearate or low molecular weight polyethylene

[0013] The ninth technical solution is based on any one of the first to eighth technical solutions, which includes the following process steps: formula selection: according to the requirements of different sports scenes for the physical properties of the front, middle and back areas of the midsole, a mixed material composed of EVA, olefin elastomer and optional inorganic powder is selected, and an appropriate amount of cross-linking agent and activator are added to formulate at least one formula for each area; weighing: weighing each formula separately; dividing the materials into three groups for weighing, including a cross-linking agent as the first group of materials, a cross-linking aid, stearic acid and zinc stearate as the second group of materials, and the remaining raw materials as the third group of materials; granulation: each The formula is mixed and granulated independently in the mixing equipment; the third group of materials is poured into the internal mixer, and the machine is started for pre-mixing; when the temperature of the internal mixer rises to 75-85 degrees, the second group of materials is added for mixing; the temperature is continued to rise to 85-95 degrees, and the first group of materials is added for sufficient mixing; when the temperature reaches 100-105 degrees, the mixed materials are poured into the granulator; the temperature of each of the four zones of the granulator is adjusted to 75 degrees, 80 degrees, 85 degrees and 90 degrees respectively, the screw speed is set to 40-50 rpm, the cutting speed is set to 15-20 rpm, and the granulation operation is performed to obtain Granulated materials for each regional component; Injection molding: The granulated materials for each regional component are respectively injection molded into each regional component of the midsole; Put the granulated materials made with the selected formula into the material barrel of the injection molding machine, set the mold cooling temperature to 10-30 degrees, and the injection molding machine melt temperature to 70-90 degrees; Adjust the material metering settings of the injection molding machine to complete the injection molding of each regional component of the midsole; Vulcanization: Put the injected regional components into the midsole embryo mold, set the mold temperature to 170-175 degrees, and the vulcanization time to 220-300 seconds to complete the vulcanization process, so that each regional component forms an integral midsole component through chemical cross-linking bonds; Foaming: The vulcanized integral midsole component is placed in a supercritical foaming reactor, the foaming temperature is set to 115-125 degrees, the foaming time is 90-150 minutes, the foaming pressure is 19-23 MPa, the foaming process is completed, and the midsole material is given the required foaming properties; Molding: the foamed semi-finished product is left to cool for 24 hours; the cooled semi-finished product is placed in a flat-plate molding mold, the hot pressing temperature is set to 175 degrees, and the hot pressing time is 360-450 seconds; use 25-degree cooling water for cooling, the cooling time is 360-450 seconds, complete the molding process, and obtain the final midsole foam material product.

[0014] The tenth technical solution is based on any one of the first to ninth technical solutions, and a midsole foam material is manufactured using the above-mentioned preparation method of a midsole foam material.

[0015] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0016] In the first technical solution and related embodiments, the method for preparing the midsole foaming material achieves accurate matching and optimization of each region of the midsole material by customizing the selection of mixed materials and formulating at least three formulas according to the different physical performance requirements of the front, middle and rear regions of the midsole of sports shoes. The method adopts a series of process steps such as mixing and granulation, injection molding, vulcanization cross-linking, supercritical foaming and molding to ensure the stable connection of the components in each region of the midsole and the realization of the required foaming performance. Specifically, according to the natural gait distribution law of the sports scene, the method designs a variety of formulas with different physical properties and accurately matches them to each region of the midsole, providing a safer, easier and more comfortable midsole experience to meet different sports needs. Through vulcanization cross-linking treatment, stable chemical cross-linking bonds are formed between the components in each region, which improves the connection strength and stability between the components. Supercritical foaming technology is used to achieve physical foaming treatment of the overall midsole components, giving the midsole material the required light weight, high elasticity, shock absorption and other foaming properties. The foamed material is shaped through the molding process to ensure the dimensional accuracy and appearance quality of the finished midsole foam material.

[0017] In the second technical scheme and related embodiments, by adjusting the usage ratio of EVA and olefin elastomer, a variety of different rebound rates can be controlled while maintaining the same foaming ratio, thereby meeting the different requirements of the front, middle and rear areas of the midsole of sports shoes for rebound performance and improving wearing comfort and sports performance.

[0018] In the third technical solution and related embodiments, by analyzing the natural gait distribution rules in different sports scenes, and then according to these rules, three to eight formulas with different physical properties are accurately matched, which can meet the physical performance requirements of the front, middle and rear areas of the sports shoe midsole in different sports scenes. And a physical foaming process is used to achieve synchronous foaming of three to eight formulas with different physical properties, ensuring the uniformity and consistency of the foaming effect between the formulas.

[0019] In the fourth technical solution and related embodiments, the increase in VA content increases the proportion of vinyl acetate units in the EVA molecular chain, thereby enhancing the elasticity and flexibility of the material.

[0020] In the fifth technical solution and related embodiments, ethylene-octene copolymer (regular copolymer or random copolymer) is a high-performance olefin elastomer with excellent elasticity, wear resistance, tear strength and low-temperature toughness. These characteristics enable the prepared midsole foam material to provide better shock absorption and durability while maintaining light weight, meeting the use requirements in different sports scenarios.

[0021] In the sixth technical solution and related embodiments, inorganic powder with a fineness greater than 600 mesh is added to the formula of the midsole foaming material, and midsole materials with different densities are achieved while maintaining the same foaming ratio, so as to meet the different density performance requirements of the front, middle and rear areas of the midsole of sports shoes.

[0022] In the seventh technical solution and related embodiments, diisopropylbenzene peroxide or 1,4-di-tert-butylperoxyisopropylbenzene (BIPB) is used as a cross-linking agent to connect the various components. Compared with the traditional glue connection solution, this method improves the connection strength between the components in various areas of the midsole, meeting the needs of various high-performance sports shoes and outdoor cross-country shoes.

[0023] In the eighth technical solution and related embodiments, active agents such as stearic acid and zinc stearate can effectively reduce the interfacial tension in the material system, making it easier to evenly disperse components such as inorganic powders, EVA, and olefin elastomers during the mixing process.

[0024] In the ninth technical solution and related embodiments, the process adopts a series of process steps such as formula selection, material weighing, granulation, injection molding, vulcanization cross-linking, supercritical foaming and molding to ensure the stable connection of components in various areas of the midsole and the realization of the required foaming performance.

[0025] In the tenth technical solution and related embodiments, this preparation method is specifically designed for midsole materials. At least three material formulas are designed, and these formulas focus on high shock absorption, high support, and high rebound rate and excellent rebound characteristics. And according to different sports scenes, the functional requirements of the midsole material in specific areas are finely matched and customized to ensure that the midsole can provide excellent shock absorption effect, rebound performance, and necessary support in practical applications, thereby effectively reducing the impact force during exercise, enhancing sports stability, and improving propulsion efficiency when pushing off the ground. This method uses physical foaming technology to achieve simultaneous foaming of three or more material formulas with different physical properties, and produce midsole foaming materials that can adapt to the natural gait of various sports scenes. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] In the claims and description of the present invention, unless explicitly defined otherwise, the terms "first", "second" or "third" etc. are used to distinguish different objects rather than to describe a specific order.

[0028] In the claims and specification of the present invention, unless otherwise expressly defined, directional words, such as the use of terms such as "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise", etc., to indicate directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the specific scope of protection of the present invention.

[0029] In the claims, specification and text of the present invention, unless otherwise clearly defined, if the term "fixed connection" or "fixed connection" is used, it should be understood in a broad sense, that is, any connection method without a displacement relationship and relative rotation relationship between the two, that is to say, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements.

[0030] In the claims and description of the present invention, when the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0031] A method for preparing a midsole foam material comprises: selecting a mixed material consisting of EVA, an olefin elastomer, and optional inorganic powder and a buffer according to the requirements of different sports scenes for the physical properties of the front, middle and rear regions of the midsole, and adding a crosslinking agent, a crosslinking aid and an active agent to formulate at least one formula for each region; weighing materials for each formula respectively, and independently mixing and granulating in a mixing device to obtain granulated materials for components in each region; injection molding the granulated materials of the components in each region into components in each region of the midsole; vulcanizing and crosslinking the injection-molded components in each region to form an integral midsole component; physically foaming the integral midsole component after vulcanization and crosslinking by using supercritical foaming technology to obtain the required foaming performance; and shaping the foamed material by a molding shaping process to obtain a finished midsole foam material.

[0032] The mixed material, by weight, includes 40-50 parts of EVA, 60-50 parts of olefin elastomer, 0-15 parts of inorganic powder, and 0-20 parts of buffer. By adjusting the usage ratio of EVA and olefin elastomer, a variety of different rebound rates can be adjusted under the premise of maintaining the same foaming ratio, meeting the different requirements of the front, middle and rear areas of the midsole of sports shoes for rebound performance, and improving wearing comfort and sports performance.

[0033] Specifically, the VA content in EVA is greater than 18%. The increase in VA content increases the proportion of vinyl acetate units in the EVA molecular chain, enhancing the elasticity and flexibility of the material. Preferred varieties include EVA33121, EVA7470, EVA265, EVA7360 and EVA28005.

[0034] The olefin elastomer is an ethylene-octene random copolymer or an ethylene-octene regular copolymer. As a high-performance olefin elastomer, ethylene-octene copolymer (whether random copolymer or regular copolymer) has excellent elasticity, wear resistance, tear strength and low-temperature toughness. These characteristics enable the prepared midsole foam material to provide better shock absorption and durability while maintaining light weight, meeting the use requirements in different sports scenarios. The preferred varieties include POE 8003, 8180, 8150, 640, 810, 740, 170, 180, 565 and OBC 9107, 9000, 9100, 9530, etc.

[0035] The inorganic powder is talcum powder, barium sulfate or calcium carbonate with a fineness greater than 600 mesh. By adding inorganic powder with a fineness greater than 600 mesh to the formula of the midsole foaming material, midsole materials with different densities can be achieved while maintaining the same foaming ratio. The different density performance requirements of the front, middle and back areas of the midsole of sports shoes can be met.

[0036] The buffer is brominated butyl rubber (BIIR), which serves to increase the cushioning and shock-absorbing capacity of the foamed product.

[0037] The crosslinking agent is a peroxide crosslinking agent, which uses one of dicumyl peroxide or 1,4-bis-tert-butyl peroxyisopropylbenzene (BIPB). Preferred varieties include DCP PERKADOX BC-FF and BIPB PERKADOX 14S-FL. Dicumyl peroxide or 1,4-bis-tert-butyl peroxyisopropylbenzene is used as a crosslinking agent to connect the various components. Compared with the traditional glue connection solution, this method improves the connection strength between the components in each area of ​​the midsole, meeting the needs of various high-performance sports shoes and outdoor off-road shoes.

[0038] The activator is one or a combination of stearic acid, zinc stearate or low molecular weight polyethylene. Stearic acid, zinc stearate and other activators can effectively reduce the interfacial tension in the material system, making it easier to evenly disperse components such as inorganic powder, EVA, olefin elastomer, etc. during the mixing process.

[0039] The crosslinking aid is zinc oxide, and the preferred variety is ZnO 997. The function of the crosslinking aid is to assist the crosslinking during crosslinking.

[0040] In this embodiment, the method for preparing the midsole foam material achieves accurate matching and optimization of each region of the midsole material by customizing the selection of mixed materials and formulating at least three formulas according to the different physical performance requirements of the front, middle and rear regions of the midsole of sports shoes. The method adopts a series of process steps such as mixing and granulation, injection molding, vulcanization cross-linking, supercritical foaming and molding to ensure the stable connection of the components in each region of the midsole and the realization of the required foaming performance. Specifically, according to the natural gait distribution law of the sports scene, the method designs a variety of formulas with different physical properties and accurately matches them to each region of the midsole, providing a safer, easier and more comfortable midsole experience to meet different sports needs. Through vulcanization cross-linking treatment, stable chemical cross-linking bonds are formed between the components in each region, which improves the connection strength and stability between the components. Supercritical foaming technology is used to achieve physical foaming treatment of the overall midsole components, giving the midsole material the required light weight, high elasticity, shock absorption and other foaming properties. Through the molding molding process, the foamed material is molded to ensure the dimensional accuracy and appearance quality of the finished midsole foam material.

[0041] A midsole foam material is manufactured using the above-mentioned method for preparing a midsole foam material. This preparation method is specifically designed for at least three material formulas for midsole materials, and these formulas focus on high cushioning, high support, and high rebound rate and excellent rebound characteristics. And according to different sports scenes, the functional requirements of the midsole material in specific areas are finely matched and customized to ensure that the midsole can provide excellent cushioning effect, rebound performance, and necessary support in actual applications, thereby effectively reducing the impact force during exercise, enhancing sports stability, and improving propulsion efficiency when pushing off the ground. This method uses physical foaming technology to achieve simultaneous foaming of three or more material formulas with different physical properties, and produce a midsole foam material that can adapt to the natural gait of various sports scenes.

[0042] According to the requirements of different sports scenes for the physical properties of the front, middle and back areas of the midsole, the number of formulas is three to eight. This embodiment adopts eight formulas. The following is a table of the eight formula ratios.

[0043] Table 1 Ratios of eight formulations

[0044]

[0045] The specific details of each material are as follows:

[0046] EVA 33121: Produced by Asia Polymer Co., Ltd., with a VA mass content of 33% and a hardness of 65A.

[0047] EVA 7360M: Produced by Formosa Plastics, with a VA content of 21% and a hardness of 86A.

[0048] EVA 28008M: Produced by LG Chem, with a VA mass content of 28% and a hardness of 78A.

[0049] OBC 9107: Produced by Dow Chemical, with a hardness of 60A, a crystallinity of 10.6%, and a melting point of 120°C.

[0050] POE 8150, 8180: Both are produced by Dow Chemical, with hardness of 72A and 60A respectively and crystallinity of 25%.

[0051] BIIR: Select the X2 model from Germany's LANXESS.

[0052] ZnO 997: Baishi brand zinc oxide, relative density between 4.42-4.45.

[0053] BIPB: We selected Akzo Nobel’s PERKADOX 14S-FL model.

[0054] Stearic acid 1801: produced by Dukuda, Indonesia.

[0055] Zinc stearate: produced by Huzhou Linghu Xinwang Chemical Co., Ltd.

[0056] The specific process steps of the above formula are as follows:

[0057] Formula selection: According to the requirements of different sports scenarios for the physical properties of the front, middle and back areas of the midsole, select a mixed material consisting of EVA, olefin elastomer, optional inorganic powder and buffer, add appropriate amounts of cross-linking agent, cross-linking aid and surfactant, and formulate at least one formula for each area.

[0058] Weighing materials: Weigh materials for each formula separately; divide the materials into three groups for weighing, including the cross-linking agent as the first group of materials, the cross-linking aid, stearic acid and zinc stearate as the second group of materials, and the remaining raw materials as the third group of materials.

[0059] Granulation: Each formula is mixed and granulated independently in the mixing equipment; the third group of materials is poured into the internal mixer and the machine is started for pre-mixing; when the temperature of the internal mixer rises to 75-85 degrees, the second group of materials is added for mixing; the temperature is continued to rise to 85-95 degrees, and the first group of materials is added for thorough mixing; when the temperature reaches 100-105 degrees, the evenly mixed materials are poured into the granulator; the temperature of each of the four zones of the granulator is adjusted to 75 degrees, 80 degrees, 85 degrees and 90 degrees respectively, the screw speed is set to 40-50 rpm, the cutting speed is set to 15-20 rpm, and the granulation operation is performed to obtain the granulated materials of the components in each zone.

[0060] Injection molding: The granulated materials of each regional component are separately injection molded into the components of each regional part of the midsole; the granulated materials with the selected formula are placed in the material barrel of the injection molding machine, and the mold cooling temperature is set to 10-30 degrees, and the melt temperature of the injection molding machine is set to 70-90 degrees; the material metering setting of the injection molding machine is adjusted to complete the injection molding of the components of each regional part of the midsole.

[0061] Vulcanization: Place the injection-molded components of each region into the midsole embryo mold, set the mold temperature to 170-175 degrees, and the vulcanization time to 220-300 seconds to complete the vulcanization process so that the components of each region form an integral midsole component through chemical cross-linking bonds.

[0062] Foaming: Place the vulcanized integral midsole component into a supercritical foaming reactor, set the foaming temperature to 115-125 degrees, the foaming time to 90-150 minutes, and the foaming pressure to 19-23 MPa to complete the foaming process and give the midsole material the required foaming properties.

[0063] Molding: Let the foamed semi-finished product stand and cool for 24 hours; put the cooled semi-finished product into a flat-plate molding mold, set the hot pressing temperature to 175 degrees, and the hot pressing time to 360-450 seconds; use 25-degree cooling water for cooling, and the cooling time is 360-450 seconds to complete the molding process and obtain the final midsole foam material product.

[0064] Table 2 Physical properties of eight formulations

[0065]

[0066]

[0067] in conclusion:

[0068] 1. According to the analysis of the above physical property data table, this method achieves three different density values ​​of 0.13, 0.15 and 0.16 at the same foaming ratio by adding inorganic powder to the formula, meeting the actual needs of the front, middle and back areas of the sole for density diversity.

[0069] 2. According to the analysis of the above physical property data table, this method achieves multiple rebound rates of 75%, 70%, 65% and 55% at the same foaming ratio by adjusting the ratio of EVA to olefin elastomer in the formula, ensuring that the front, middle and rear areas of the sole can obtain the required rebound performance.

[0070] 3. According to the analysis of the above physical property data table, this method achieves multiple hardness values ​​of 40, 43, 38, 45 and 42 at the same foaming ratio by adjusting the amount of high hardness and low hardness materials in the formula, so that the front, middle and rear areas of the sole can match their respective required hardness characteristics.

[0071] The description of the above specification and embodiments is used to explain the protection scope of the present invention, but does not constitute a limitation on the protection scope of the present invention. Through the enlightenment of the present invention or the above embodiments, ordinary technicians in this field can obtain modifications, equivalent substitutions or other improvements to the embodiments of the present invention or part of the technical features thereof through logical analysis, reasoning or limited experiments, which should be included in the protection scope of the present invention.

Claims

1. A method for preparing a midsole foam material, characterized in that: include: According to the requirements of different sports scenes for the physical properties of the front, middle and back areas of the midsole, a mixed material composed of EVA, olefin elastomer, optional inorganic powder and buffer is selected, and a cross-linking agent, a cross-linking aid and an active agent are added to formulate at least one formula for each area; the materials are weighed separately for each formula, and the mixing and granulation are independently carried out in a mixing equipment to obtain granulated materials for components in each area; the granulated materials of the components in each area are injection molded into components in each area of ​​the midsole; the components in each area after injection molding are vulcanized and cross-linked to form an integral midsole component; the overall midsole component after vulcanization and cross-linking is physically foamed by supercritical foaming technology to obtain the desired foaming performance; the foamed material is finalized by a molding process to obtain a finished midsole foam material.

2. The method for preparing a midsole foam material according to claim 1, characterized in that: The mixed material comprises, by weight, 40-50 parts of EVA, 60-50 parts of olefin elastomer, 0-15 parts of inorganic powder, and 0-20 parts of buffer.

3. The method for preparing a midsole foam material according to claim 2, characterized in that: According to the requirements of different sports scenarios for the physical properties of the front, middle and back areas of the midsole, the number of the formulas ranges from three to eight.

4. The method for preparing a midsole foam material according to claim 2, wherein: The VA content in the EVA is greater than 18%.

5. The method for preparing a midsole foam material according to claim 2, wherein: The olefin elastomer is an ethylene-octene random copolymer or an ethylene-octene regular copolymer.

6. The method for preparing a midsole foam material according to claim 2, wherein: The inorganic powder is talcum powder, barium sulfate or calcium carbonate with a fineness greater than 600 meshes.

7. The method for preparing a midsole foam material according to claim 2, wherein: The crosslinking agent is a peroxide crosslinking agent, which is one of dicumyl peroxide and 1,4-di-tert-butyl peroxycumene.

8. The method for preparing a midsole foam material according to claim 2, wherein: The active agent is one or a combination of two of stearic acid, zinc stearate or low molecular weight polyethylene.

9. A method for preparing a midsole foam material according to any one of claims 1 to 8, characterized in that: The process steps include: Formula selection: According to the requirements of different sports scenes on the physical properties of the front, middle and back areas of the midsole, select a mixed material consisting of EVA, olefin elastomer, optional inorganic powder and buffer, add appropriate amounts of cross-linking agent, cross-linking aid and activator, and formulate at least one formula for each area; Weighing materials: Weigh materials for each formula separately; divide the materials into three groups for weighing, including the cross-linking agent as the first group of materials, the cross-linking auxiliary agent, stearic acid and zinc stearate as the second group of materials, and the remaining raw materials as the third group of materials; Granulation: Each formula is mixed and granulated independently in the mixing equipment; the third group of materials is poured into the internal mixer and the machine is started for pre-mixing; When the temperature of the internal mixer rises to 75-85 degrees, add the second group of materials for mixing; continue to raise the temperature to 85-95 degrees, then add the first group of materials for sufficient mixing; when the temperature reaches 100-105 degrees, pour the mixed materials into the granulator; adjust the temperature of the four zones of the granulator to 75 degrees, 80 degrees, 85 degrees and 90 degrees respectively, set the screw speed to 40-50 rpm, the cutting speed to 15-20 rpm, and perform granulation operation to obtain granulated materials of components in each zone; Injection molding: The granulated materials of each regional component are respectively injection molded into the regional components of the midsole; the granulated materials with the selected formula are placed in the material barrel of the injection molding machine, and the mold cooling temperature is set to 10-30 degrees, and the melt temperature of the injection molding machine is set to 70-90 degrees; the material metering setting of the injection molding machine is adjusted to complete the injection molding of the regional components of the midsole; Vulcanization: Place the injection-molded components of each region into the midsole embryo mold, set the mold temperature to 170-175 degrees, and the vulcanization time to 220-300 seconds to complete the vulcanization process, so that the components of each region form an integral midsole component through chemical cross-linking bonds; Foaming: Put the vulcanized integral midsole component into a supercritical foaming reactor, set the foaming temperature to 115-125 degrees, the foaming time to 90-150 minutes, and the foaming pressure to 19-23 MPa to complete the foaming process and give the midsole material the required foaming properties; Molding: Let the foamed semi-finished product stand and cool for 24 hours; put the cooled semi-finished product into a flat-plate molding mold, set the hot pressing temperature to 175 degrees, and the hot pressing time to 360-450 seconds; use 25-degree cooling water for cooling, and the cooling time is 360-450 seconds to complete the molding process and obtain the final midsole foam material product.

10. A midsole foam material, characterized in that: The midsole foam material is manufactured by the preparation method of the midsole foam material according to any one of claims 1 to 9.

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