An EVA foamed shoe sole material, its preparation method and application

Abstract

This invention discloses an EVA foamed shoe sole material, its preparation method, and its application, belonging to the field of footwear products. The EVA foamed shoe sole material is obtained by foaming an EVA composite material, which includes: 40-60 parts of ethylene-vinyl acetate copolymer, 10-20 parts of random polyolefin elastomer, 5-20 parts of ethylene-butyl acrylate polymer, 5-20 parts of hydrogenated styrene-ethylene / butene-styrene block copolymer, and 5-20 parts of brominated isobutylene-p-methylstyrene copolymer elastomer; 2-5 parts of tackifier; 3-6 parts of wet slip agent; 3-5 parts of nano-hydrophilic filler; 3-5 parts of abrasion resistant agent; 2.5-3.5 parts of foaming agent; and a crosslinking agent and an activator. The foamed shoe sole material provided by this invention is lightweight and has good slip resistance and abrasion resistance properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of footwear products, in particular to an EVA foamed sole material and a preparation method and application thereof. BACKGROUND

[0002] With the increasing emphasis on health by consumers, various sports such as jogging and hiking are deeply loved by consumers, and good performance of these sports cannot be achieved without a good pair of sports shoes. A good pair of sports shoes not only improves the sports performance of the wearer, but also needs to have good safety and effectively protect the feet. The traditional ethylene-vinyl acetate copolymer (EVA) foamed sole has been widely used in the field of shoe materials due to its light weight, softness, high elasticity, shock absorption, comfort and other advantages.

[0003] However, ordinary EVA foamed sole material is difficult to balance slip resistance and wear resistance. The main reason is that ordinary EVA foamed sole usually uses silicone wear-resistant agent, which can improve the wear resistance of the foamed sole, but the lubricity of silicone leads to the decrease of the slip resistance of the sole, and the principles of slip resistance and wear resistance are to some extent contrary. Therefore, the slip resistance of ordinary EVA foamed material is poor, especially in wet and slippery environment, which is difficult to meet the needs of users for safety and comfort.

[0004] There are some improvement measures in the industry at present; for example, adding fillers or changing the surface structure to improve the slip resistance, but these methods often have problems such as complex processing, high cost or unstable performance. Or by adhering wear-resistant and slip-resistant rubber outsole under the EVA foamed insole, the unfoamed rubber outsole has good wear resistance and slip resistance, but the density is large, which cannot meet the light weight requirement of consumers for sports shoes. SUMMARY

[0005] Therefore, the present application provides an EVA foamed sole material and a preparation method and application thereof. The foamed sole material provided by the present application is light in weight and has good slip resistance and wear resistance.

[0006] The present application provides an EVA foamed sole material, which is prepared from an EVA composite material. The EVA composite material comprises, by weight:

[0007] 40-60 parts of ethylene-vinyl acetate copolymer, 10-20 parts of random polyolefin elastomer, 5-20 parts of ethylene-butyl acrylate polymer, 5-20 parts of hydrogenated styrene-ethylene / butylene-styrene block copolymer and 5-20 parts of brominated isobutylene-p-methylstyrene copolymer elastomer; 2-5 parts of tackifier; 3-6 parts of wet slip agent; 3-5 parts of nano hydrophilic filler; 3-5 parts of wear-resistant agent; 2.5-3.5 parts of foaming agent; and crosslinking agent and active agent.

[0008] In some embodiments, the VA content of the ethylene-vinyl acetate copolymer is 25-35 wt%; and / or, the acrylic structure content of the ethylene-butyl acrylate polymer is 20-35 wt%.

[0009] In some embodiments, the vinyl content of the hydrogenated styrene-ethylene / butylene-styrene block copolymer is 3-5 wt%; and / or, the bromine content of the brominated isobutylene-p-methylstyrene copolymer elastomer is 1-3 wt%.

[0010] In some embodiments, at least one of the following is satisfied: the tackifier is an alkyl phenol-formaldehyde resin; the wet slip agent is a polyacrylic acid resin; the wear resistant agent is a vinyl silicone oil with a room temperature viscosity of 80-100 million mpa.s; and the nano hydrophilic filler is a nanocellulose.

[0011] In some embodiments, the blowing agent is one or more of azodicarbonamide, expanded microspheres and 4,4-oxadiazolidine; and / or, the EVA compound includes 0.4-0.6 parts of a peroxide crosslinking agent.

[0012] In some embodiments, the active agent includes 1.0-1.5 parts of zinc oxide, 0.5-1.0 parts of stearic acid and 0.5-1.0 parts of zinc stearate.

[0013] In some embodiments, the EVA foamed sole material satisfies at least one of the following: a resilience rate ≥ 60%; a density of 0.11-0.19 g / cm 3 ; a dry slip ≥ 0.8; and a wet slip ≥ 0.5.

[0014] The present application provides a preparation method of the EVA foamed sole material as described above, comprising the following steps:

[0015] The EVA compound is subjected to a one-shot foaming process or a compression-molding secondary foaming process to obtain the EVA foamed sole material.

[0016] In some embodiments, the EVA compound is subjected to mixing and granulation before foaming in the one-shot foaming process and the compression-molding secondary foaming process.

[0017] The present application provides a sports shoe comprising the EVA foamed sole material as described above.

[0018] Compared with the prior art, the EVA foamed shoe sole material provided by the application is prepared by foaming an EVA compound material, and the EVA compound material mainly comprises: 40-60 parts of ethylene-vinyl acetate copolymer (EVA), 10-20 parts of random polyolefin elastomer (POE), 5-20 parts of ethylene-butyl acrylate polymer (EBA), 5-20 parts of hydrogenated styrene-ethylene / butylene-styrene block copolymer (SEBS) and 5-20 parts of brominated isobutylene-p-methyl styrene copolymer elastomer (BIMSM), and a certain amount of tackifier, wet skid resistance agent, wear resistance agent, nano hydrophilic filler and foaming agent. The EVA foamed shoe sole with excellent dry and wet skid resistance and other properties can be obtained by mainly adopting the excellent skid resistance BIMSM and SEBS, tackifier and wet skid resistance agent, nano hydrophilic filler and EVA / POE / EBA polymer co-crosslinking foaming. The experiment shows that the static dry skid resistance is greater than or equal to 1.0, the static wet skid resistance is greater than or equal to 0.8, the dynamic dry skid resistance is greater than or equal to 0.8, the dynamic wet skid resistance is greater than or equal to 0.5, and the rebound rate is greater than or equal to 60%. The problems that the skid resistance and wear resistance of the existing EVA foamed shoe sole are difficult to be considered together are solved, the EVA midsole can be used in a large area and directly touch the ground, and the application in sports shoes is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The figure is a one-shot foaming process flowchart of some embodiments of the application.

[0020] Figure 2 The figure is a two-shot foaming process flowchart of some embodiments of the application. DETAILED DESCRIPTION

[0021] In order to more clearly understand the technical features, objectives and effects of the application, the technical solutions of the application will be described in detail below in combination with specific embodiments. The described embodiments are only some embodiments of the application, not all embodiments.

[0022] The application provides an EVA foamed shoe sole material prepared by foaming an EVA compound material. The EVA compound material comprises, by weight:

[0023] 40-60 parts of ethylene-vinyl acetate copolymer, 10-20 parts of random polyolefin elastomer, 5-20 parts of ethylene-butyl acrylate polymer, 5-20 parts of hydrogenated styrene-ethylene / butylene-styrene block copolymer and 5-20 parts of brominated isobutylene-p-methyl styrene copolymer elastomer; 2-5 parts of tackifier; 3-6 parts of wet skid resistance agent; 3-5 parts of nano hydrophilic filler; 3-5 parts of wear resistance agent; 2.5-3.5 parts of foaming agent; and crosslinking agent and active agent.

[0024] The foamed shoe sole material provided by the embodiment of the present application can meet the lightness, softness, high elasticity, cushioning, wear resistance and skid resistance of the EVA foamed sports shoe sole, and can especially meet the safety and comfort requirements of users in a wet and slippery environment.

[0025] In the polymer matrix composition, the EVA compound material for foaming into shoe material is organically matched by introducing ethylene-vinyl acetate copolymer EVA, random polyolefin elastomer POE, ethylene-butyl acrylate polymer EBA, hydrogenated styrene-ethylene / butylene-styrene block copolymer SEBS and brominated isobutylene-p-methylstyrene copolymer elastomer BIMSM, etc. The ethylene-vinyl acetate copolymer is abbreviated as EVA, which is copolymerized by ethylene and vinyl acetate (VA) through high-pressure bulk polymerization process, and the VA structure content in the molecular chain has a certain influence on the performance. It has good foaming performance and is one of the core matrices for preparing foaming materials, which can ensure the formation of uniform pore structure during the foaming process.

[0026] In some embodiments, the mass fraction of the ethylene-vinyl acetate copolymer is 40-60 parts, for example, 40 parts, 45 parts, 50 parts, 60 parts, etc. The ethylene-vinyl acetate copolymer preferably includes EVA with a VA content of 25-35wt%; the preferred varieties on the market are EVA 7470M (Taiwan Plastic Company) and EVA 33121 (DuPont Company).

[0027] The random polyolefin elastomer is abbreviated as POE, and POE (Polyolefin Elastomer) is mainly a thermoplastic elastomer copolymerized by ethylene and α-olefin (such as butene, octene, etc.) through metallocene catalyst. Its molecular chain is flexible, showing excellent resilience and flexibility, which can provide comfortable rebound foot feeling and excellent cushioning effect in the sports shoe sole. In some embodiments, the mass fraction of POE is 10-20 parts, for example, 10 parts, 12 parts, 15 parts, 20 parts, etc. The POE includes ethylene-octene copolymer, and the preferred products on the market are LC170 of LG Company in South Korea, etc., with a hardness of 71A.

[0028] The ethylene-butyl acrylate polymer, referred to as EBA, is formed by free radical polymerization of ethylene and butyl acrylate under high temperature and high pressure. EBA is known for its excellent polarity, shrinkage resistance and compression resistance, and can significantly improve the durability and long-term performance of the material, and is particularly suitable for scenarios requiring frequent compression. The ethylene-butyl acrylate polymer preferably includes a product with an acrylate structure content of 20-35 wt%, and further preferably an EBA with an acrylate content of 27-32 wt%, and the specific variety can be EVA 3427 (DuPont, USA). In some embodiments, the mass fraction of EBA is 5-20 parts, such as 5 parts, 6 parts, 10 parts, 15 parts, 20 parts, etc.

[0029] In the above-mentioned EVA-based formula, the present application preferably introduces a brominated isobutylene-p-methylstyrene copolymer elastomer BIMSM with excellent slip resistance and a high ethylene content SEBS. Among them, the high ethylene content hydrogenated styrene-ethylene / butylene-styrene block copolymer SEBS has excellent dry slip resistance, elasticity and fatigue resistance, which can effectively improve the friction of the sole in dry environment, and at the same time enhance its wear resistance and service life.

[0030] In some embodiments, the mass fraction of the hydrogenated styrene-ethylene / butylene-styrene block copolymer is 5-20 parts, such as 5 parts, 10 parts, 15 parts, 18 parts, 20 parts, etc. The SEBS is usually a linear three-embedded copolymer with polystyrene as the terminal segment and ethylene-butene copolymer obtained by hydrogenation of polybutadiene as the middle elastic segment; SEBS preferably includes a high ethylene content grade with a styrene mass content of <35% and an ethylene mass content of 3-5%, and the preferred commercially available variety is SEBSL1606 (Asahi Kasei, Japan) and the like.

[0031] The brominated isobutylene-p-methylstyrene copolymer elastomer, referred to as BIMSM, is a brominated isobutylene-p-methylstyrene terpolymer, which contains a large number of side groups (-Br, -CH3, etc.) in its molecular structure. Due to its special molecular structure, BIMSM exhibits excellent high damping performance and slip resistance, and performs particularly outstandingly in wet and slippery environments. In some embodiments, the mass fraction of the brominated isobutylene-p-methylstyrene copolymer elastomer is 5-20 parts, such as 5 parts, 8 parts, 10 parts, 15 parts, 20 parts, etc. As a preferred, the BIMSM includes a product with a bromine mass content of 1.0%-3.0%, an isobutylene content of 87%-94%, an isoprene content of 1.0%-3.0%, and a styrene content of 5%-10%, and the preferred variety is Exxpro3745 (ExxonMobil) and the like.

[0032] Further, the tackifier alkyl phenolic resin with excellent tackifying effect and the wet slip resistance agent polyacrylic resin are used to improve the material performance. That is, the tackifier is preferably alkyl phenolic resin, and para-tert-butyl phenol formaldehyde resin is mainly selected, which is one of the effective tackifiers in ordinary rubber products, and the tackifying mechanism includes: ① flow carrier effect: the alkyl phenolic resin forms a blending system with the polymer in the rubber compound, and the resin molecules are migrated to different rubber compound interfaces through the flowability of the polymer to realize effective contact and wetting between the interfaces. ② Bridge effect: the resin molecules form a "molecular bridge" between the rubber compound interfaces through physical adsorption and chemical bonding (such as hydrogen bond, van der Waals force), which significantly improves the interfacial adhesion to make the multi-component rubber compound adhere to a uniform whole. ③ Hydrogen bond network strengthening: the hydroxyl (-OH) in the resin molecules forms a hydrogen bond network with the polar groups (such as ester groups in EVA / EBA) on the polymer chain, which enhances the cohesive strength of the polymer and improves the anti-peeling performance of the material. When it is added to the EVA foaming formula, on the one hand, the formation of the hydrogen bond network improves the surface density of the material and reduces the dynamic friction coefficient, so that the shoe sole has both slip resistance and flexibility in dry environment. On the other hand, the interfacial adhesion of the resin effectively improves the adhesion strength of the EVA foaming layer and other parts of the shoe sole, which is beneficial to reduce the risk of delamination, etc.

[0033] In the preferred embodiments of the present application, the wet slip resistance agent is selected from polyacrylic resin, which can realize the hydrophilic interface regulation on the one hand: the polyacrylic resin molecular chain is rich in carboxylic acid groups (-COOH), which can quickly adsorb water molecules through hydrogen bond interaction in the water-containing road surface environment to form a dynamic hydrophilic interface layer; the interface layer can destroy the water film between the shoe sole and the road surface, increase the micro contact area, and thus improve the friction coefficient under wet slip condition, and the wet friction coefficient can be increased by 30%-40%. On the other hand, the polyacrylic resin and the EBA polymer in the formula both contain acrylate groups (-COOR), and the two can realize uniform dispersion between the molecular chains through the principle of similar polarity. This compatibility is beneficial to avoid performance degradation caused by phase separation, and promotes the resin and the matrix to form a stable interpenetrating network structure to achieve molecular level compatibility, etc.

[0034] In some embodiments, the tackifier includes para-tert-butyl phenol formaldehyde resin, and the mass fraction is 2-5 parts, preferably 3-4 parts; and the preferred specific variety can be tackifier resin 204 produced by Hubei Xingyan New Material Technology Co., Ltd., with a molecular weight of 180.24. In some embodiments, the wet slip resistance agent preferably includes polyacrylic resin, and the preferred variety is BR-116 commercially available product (Mitsubishi Corporation, Japan), with a viscosity (25°C) of 300-370 mpa.s. The mass fraction of the wet slip resistance agent is 3-6 parts, such as 3 parts, 4 parts, 5 parts, 6 parts, etc.

[0035] In addition, the EVA compound material includes 3-5 parts of nano-hydrophilic filler, which can be 3 parts, 4 parts, 5 parts, etc. The nano-hydrophilic filler is further selected from nano-cellulose. The nano-cellulose has high strength (such as tensile strength of about 7.5 Gpa, elastic modulus of about 150 GPa), high specific surface area and high adsorption (its width is less than or equal to 100 nm, length is several hundred nanometers to micrometer level, and the network structure provides a large specific surface area, which can reach 500 m 2 / g). Moreover, the surface of the nano-cellulose is rich in hydrophilic groups such as hydroxyl (-OH) and carboxyl (-COOH), which can form hydrogen bonds with water molecules, thereby imparting good hydrophilicity. In addition, the high specific surface area enables the nano-cellulose to fully contact with water molecules, thereby further strengthening the hydrophilic effect. Meanwhile, the nano-cellulose also has the characteristics of light weight (density is only 1 / 6 of steel). In the preferred embodiments of the present application, the nano-cellulose contains hydroxyl groups / carboxyl groups and the like, which are beneficial to form strong hydrogen bonds with acrylic resin and the like, thereby improving the mechanical properties and wet skid resistance of the foamed shoe sole. Specifically, the nano-cellulose includes cellulose material with a diameter of 10-100 nm and a length of 1-100 μm, and preferred varieties include nano-cellulose CNF-H1 (Zhejiang Jinjiahao Green Nanomaterials Co., Ltd.) and the like.

[0036] The EVA compound material includes 3-5 parts of wear-resistant agent by weight. The wear-resistant agent is preferably high-molecular vinyl silicone oil, and is further a methyl vinyl polysiloxane with a vinyl group in the middle of the molecular chain, and the room temperature viscosity is between 80,000-100,000 (mpa.s). Specifically, the wear-resistant agent with a viscosity of 100,000 is preferably used, such as variety V-100000 (Jiangsu Keqi High Polymer Material Research Institute Co., Ltd.) and the like.

[0037] The EVA compound material includes, by weight: 0.4-0.6 parts of peroxide crosslinking agent; 2.5-3.5 parts of foaming agent; 1.0-1.5 parts of zinc oxide, 0.5-1.0 parts of stearic acid, and 0.5-1.0 parts of zinc stearate (which can promote crosslinking and foaming). The foaming agent is preferably one of azodicarbonamide, expanded microspheres, and 4,4-oxadiazolidine, and the preferred variety is azodicarbonamide AC6000H. The peroxide crosslinking agent can include one of dicumyl peroxide and 1,4-bis-tert-butyl peroxide isopropyl benzene (which can be referred to as crosslinking agent BIPB); and the preferred variety is BIBP 14S-FL and the like.

[0038] Embodiments of the present application ingeniously match ethylene-vinyl acetate, random polyolefin elastomer, ethylene-butyl acrylate polymer, high ethylene content hydrogenated styrene-ethylene / butylene-styrene block copolymer and brominated isobutylene-p-methylstyrene copolymer elastomer, and further combine alkyl phenolic resin with excellent tackifying effect and wet slip-resistant polyacrylic acid resin, nanocellulose and EVA / POE / EBA crosslinking foaming to finally prepare an EVA foaming sole material with excellent dry and wet slip resistance. In some embodiments, the EVA foaming material is a sole material, and its slip resistance includes: static dry slip ≥ 1.0, static wet slip ≥ 0.8, dynamic dry slip ≥ 0.8, and dynamic wet slip ≥ 0.5; at the same time, it can maintain excellent lightness, softness, high elasticity, wear resistance and other properties, solves the problems of existing EVA foaming sole slip resistance, wear resistance and other problems, meets the demand of indoor and outdoor wet sports scenes, and improves the safety of sports.

[0039] Embodiments of the present application provide a preparation method of the EVA foaming sole material described above, comprising the following steps: subjecting the EVA composite material to a one-shot foaming process or a two-step foaming process to obtain the EVA foaming sole material.

[0040] Referring to Figure 1 The implementation steps of the one-shot foaming process (abbreviated as IP process) of some embodiments of the present application are as follows:

[0041] ① Weighing: according to the amount of the formula, the crosslinking agent and the foaming agent are weighed as the first group; the stearic acid, zinc stearate and zinc oxide are weighed as the second group; and the remaining materials are weighed as the third group.

[0042] ② Mixing: first, pour the third group of materials into the internal mixer, and turn on the machine; when the temperature rises to 85-95℃, pour in the second group of materials; when the temperature rises to 95-100℃, pour in the first group of materials; and when the temperature rises to 100-110℃, pour out the mixed materials.

[0043] ③ Granulation: pour the mixed materials into the material making machine, and preferably adjust the temperatures of the first, second, third and fourth zones to 80℃, 85℃, 90℃ and 95℃ respectively, and adjust the screw speed to 45-55 revolutions / minute and the cutting speed to 18-23 revolutions / minute.

[0044] ④ Foaming: pour the prepared materials into the injection molding foaming machine, and preferably adjust the temperatures of the first, second, third and fourth zones to 80℃, 85℃, 90℃ and 95℃ respectively, and adjust the temperatures of the upper and lower mold plates of the molding mold to 175±5℃ and 175±5℃ respectively. Set the material amount according to the amount of the sole mold (according to the foaming ratio of 170%, the material amount can be set to 100±10g), the injection time can be 200±20 seconds, and the vulcanization and foaming time is 600±30 seconds.

[0045] ⑤ Baking: Set the temperatures of the first, second, third, and fourth zones of the oven to 80℃, 90℃, 95℃, and 100℃ respectively, and the rotation speed to 50-60 rpm; send the foamed material into the oven opening, and the oven length should be 30 meters; the baking time from start to finish should be 30-40 minutes.

[0046] See Figure 2 The implementation steps of the compression molding secondary foaming process (MD process for short) in other embodiments of the present invention are described below:

[0047] Among them, the processes of weighing, mixing, and granulation are consistent with IP processes ①, ②, and ③.

[0048] Small foaming: Pour the prepared granules into a flat mold for small foaming to complete the first foaming. The preferred foaming temperature is 170-180℃; the foaming time can be 500±50 seconds.

[0049] Compression molding: After the foamed semi-finished product has been left to stand and cool for 24 hours, it is pressed into a flat molding die to complete the molding of the finished product; the hot pressing temperature is preferably 173±3℃; the hot pressing time can be 450±30 seconds; the cooling water temperature can be 25℃ and the cooling time can be 400±20 seconds.

[0050] The EVA foam sole material prepared according to the embodiments of the present invention is suitable for IP process or MD process; the EVA foam sole material can be an EVA foam sole with excellent dry and wet anti-slip performance, and preferably meets at least one of the following: rebound rate ≥60%; density of 0.11~0.19g / cm³. 3 Static dry slip ≥1.0, static wet slip ≥0.8, dynamic dry slip ≥0.8, dynamic wet slip ≥0.5; national standard wear mark ≤11.5; compression deformation ≤42%; delamination tear ≥23N / CM.

[0051] This invention provides an athletic shoe comprising the aforementioned EVA foam sole material; it can be used as a large exposed area of ​​the EVA midsole or for direct contact with the ground. Based on the aforementioned EVA foam sole material, the athletic shoe exhibits excellent performance.

[0052] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments. In the embodiments, all original reagents and materials are commercially available, and experimental methods not specifying specific experimental conditions are conventional methods and conditions well known in the art.

[0053] Example 1

[0054] ① Weighing: Based on the dosage of the formula in Table 1, weigh BIBP and foaming agent as the first group; weigh stearic acid, zinc stearate, and zinc oxide as the second group; weigh the remaining materials as the third group.

[0055] ② Mixing: first pour the third group of materials into the internal mixer, and turn on the machine, when the temperature rises to 85-95℃, pour in the second group of materials; when the temperature rises to 95-100℃, pour in the first group of materials; when the temperature rises to 100-110℃, pour out the mixed materials.

[0056] ③ Granulation: pour the mixed materials into the material making machine, and adjust the temperatures of the first, second, third and fourth zones to 80, 85, 90 and 95℃ respectively, and adjust the screw rotation speed to 45-55 revolutions per minute, and adjust the cutting material rotation speed to 18-23 revolutions per minute.

[0057] ④ Foaming: pour the prepared materials into the injection molding foaming forming machine, and adjust the temperatures of the first, second, third and fourth zones to 80, 85, 90 and 95℃ respectively, and adjust the temperatures of the upper and lower mold plates of the forming mold to 175±5℃ and 175±5℃ respectively. Set the material amount according to the amount required by the sole mold (according to the foaming ratio of 170%, the material amount can be set to 100±10g), the injection time is 200±20 seconds, and the vulcanization foaming time is 600±30 seconds.

[0058] ⑤ Baking: adjust the temperatures of the first, second, third and fourth zones to 80, 90, 95 and 100℃ respectively, and the rotation speed is 50-60 revolutions per minute; send the foamed material formed into the oven, and the length of the oven is selected to be 30 meters long; the baking time from the beginning to the end is 35 minutes, and the EVA foamed sole material sample is obtained.

[0059] Examples 2-16

[0060] According to the implementation steps of Example 1, the formula composition is shown in Table 1, Table 2, and EVA foamed sole material samples are obtained respectively.

[0061] Comparative Examples 1-9

[0062] According to the implementation steps of Example 1, the formula composition is shown in Table 3, and EVA foamed sole material samples are obtained respectively.

[0063] Table 1 Formula of Examples 1-8 of the application:

[0064]

[0065]

[0066] Table 2 Formula of Examples 9-16 of the application:

[0067]

[0068]

[0069] Table 3 Formula of Comparative Examples 1-9 of the application:

[0070]

[0071]

[0072] wherein:

[0073] EVA 7470M: VA mole content 26%, hardness 82A, melting point 76°C, crystallinity 24.8%, Taiwan Plastics Corporation.

[0074] POE LC170: hardness 71A, melting point 58°C, tensile strength 9.0 MPa, tear strength 40 KN / m, elongation at break 700%, LG Corporation, Korea.

[0075] EBA 3427: acrylic acid content 27%, hardness 81A, melting point 94°C, tensile strength 25 MPa, DuPont Company, USA.

[0076] Exxpro 3745: bromine content 2.3 wt%, isobutylene content 90%, isoprene content 2.5%, styrene content 7.5%, Mooney viscosity 45 ML (1+8) / 125°C, Exxon Mobil Corporation.

[0077] SEBS S1606: hardness 67A, tensile strength 20 MPa, elongation at break 490%, styrene mole content 20%, 1-2 vinyl content 4%, Asahi Kasei Corporation, Japan.

[0078] Tackifying resin 204: yellow granules, molecular weight 180.24, boiling point 233.7°C, flash point 110.9°C, Hubei Xingyan New Material Technology Co., Ltd.

[0079] BR-116: white granules, molecular weight 45,000, viscosity 300-370 mpa.s at 25°C, Mitsubishi Corporation, Japan.

[0080] Nanocellulose CNF-H1: white powder, diameter 20-80 nm, diameter 1-20 um, Zhejiang Jinggaohuo Green Nanometer Material Co., Ltd.

[0081] V-100,000: viscosity 100,000 (mp.s), Jiangsu Keqi High Polymer Material Research Institute Co., Ltd.

[0082] BIBP 14S-FL: white granules, Akzo Nobel. Foaming agent AC6000H: yellow powder, Hangzhou Haihong Fine Chemical Co., Ltd.

[0083] ZnO 997: white powder, Shipai Zinc Oxide, relative density 4.42-4.45.

[0084] Stearic acid 1801: white granules, Indonesia Dukuh.

[0085] Zinc stearate: white powder, Huzhou Linghu Xiwang Chemical Co., Ltd.

[0086] The EVA foamed sole material samples of the examples and comparative examples were tested for performance, and the results are as follows.

[0087] Table 4 Example 1-8 sample performance data table

[0088]

[0089] Table 5 Example 9-16 sample performance data table

[0090]

[0091]

[0092] Table 6 Comparative Example 1-9 sample performance data table

[0093]

[0094]

[0095] From the test data of Examples 1-16, it can be seen that by adjusting EVA 7470M 40-60 parts, POE LC170 10-20 parts, EBA 3427 5-20 parts, BIMSM Exxpor 3745 5-20 parts, SEBS L1606 5-20 parts, tackifying resin 204 2-5 parts, wet skid resistance BR-116 3-6 parts, nanocellulose CNF-H1 3-5 parts, wear-resistant agent V-10000 3-5 parts, peroxide crosslinking agent BIBP 0.5 parts, foaming agent AC6000H 2.7 parts, zinc oxide ZnO 1.25 parts, stearic acid 1801 parts, zinc stearate 1.0 parts, a foamed sole can be obtained with static dry slip ≥1.0, static wet slip ≥0.8, dynamic dry slip ≥0.8, dynamic wet slip ≥0.5, rebound rate ≥60%, national standard indentation ≤11.5, compression set ≤42%, delamination tear ≥23N / CM. When the anti-skid reaches a certain limit, every 0.1 difficulty will increase (anti-skid performance has no unit).

[0096] From the test data of Examples 5 / 6 / 7 / 8 and Comparative Example 4, it can be seen that as the amount of tackifying resin added increases, the static and dynamic dry slip resistance of the sole increases, and when the amount added is 0, the dry slip resistance decreases significantly. This shows that the -tert-butyl phenol formaldehyde resin molecules form a "molecular bridge" between the interfaces of the rubber by physical adsorption and chemical bonding (such as hydrogen bonding, van der Waals forces), significantly improving the interfacial adhesion; on the other hand, the hydroxyl groups (-OH) in the resin molecules form a hydrogen bond network with the polar groups on the polymer chain (such as the ester groups in EVA / EBA), enhancing the polymer's cohesive strength and improving the surface density of the material, thereby reducing the dynamic friction coefficient and improving the dry slip resistance of the sole.

[0097] From the test data of Examples 5 / 9 / 10 / 11 and Comparative Example 5, it can be seen that as the amount of wet slip inhibitor polyacrylic resin added increases, the static and dynamic wet slip resistance of the sole increases, and when the amount added is 0, the wet slip resistance decreases significantly. This shows that the -COOH in the polyacrylic resin molecular chain can quickly adsorb water molecules in a water-containing road surface environment through hydrogen bonding, forming a dynamic hydrophilic interface layer. This interface layer can break the water film between the sole and the road surface, increasing the microscopic contact area and thus improving the wet slip resistance.

[0098] From the test data of Examples 5 / 12 / 13 and Comparative Example 6, it can be seen that as the amount of nanocellulose added increases, the static and dynamic wet slip resistance of the sole increases, and when the amount added is 0, the wet slip resistance decreases significantly. This shows that the hydroxyl and carboxyl groups on the surface of nanocellulose form hydrogen bonds with water molecules, giving it strong hydrophilicity. In addition, the high specific surface area allows it to come into full contact with water molecules, further enhancing the hydrophilic effect and improving the wet slip resistance of the foamed sole.

[0099] From the test data of Examples 5 / 14 / 15, it can be seen that as the amount of wear-resistant agent added increases, the wear resistance of the sole improves, but the wet slip resistance and wet slip resistance decrease, which is mainly because the molecular chain of the silicone wear-resistant agent is Si-O bond, which has very high flexibility, so it can reduce wear and friction, but the slip resistance decreases.

[0100] From the test data of Example 5 and Comparative Example 1, it can be seen that if EBA 3427 is not added, the static and dynamic dry and wet slip resistance and compression performance of the foamed sole all decrease, which shows that the absence of EBA in the formula weakens the compatibility of the polyacrylic resin with other matrices, and it cannot form a stable interpenetrating network structure with other polymer matrices, leading to a certain degree of performance degradation.

[0101] From the test data of Example 5 and Comparative Example 2, it can be seen that if the brominated isobutylene-p-methylstyrene copolymer elastomer BIMSM is not added, the static and dynamic wet slip resistance of the foamed shoe sole is greatly reduced, indicating that the large amount of side groups (-Br, -CH3, etc.) in the molecular structure of BIMSM is beneficial to improve the wet slip resistance.

[0102] From the test data of Example 5 and Comparative Example 3, it can be seen that if the high ethylene content SEBS is not added, the static and dynamic dry slip resistance of the foamed shoe sole is greatly reduced, indicating that the higher the content of the ethylene side group in the high ethylene content SEBS, the more beneficial to improve the dry slip resistance.

[0103] From the test data of Example 5 and Comparative Examples 7 / 8 / 9, it can be seen that whether no tackifier / wet slip agent / nano-cellulose or no high ethylene content SEBS / BIMSM is added, or none of the above five is added, all will cause the static / dynamic dry / wet slip resistance of the foamed shoe sole to be greatly reduced, indicating that the technical solution of the present application, which is to combine ethylene-vinyl acetate EVA, random copolymer polyolefin elastomer POE, ethylene-butyl acrylate polymer EBA, high ethylene content hydrogenated styrene-ethylene / butylene-styrene block copolymer SEBS and brominated isobutylene-p-methylstyrene copolymer elastomer BIMSM, and then combine the excellent tackifying effect of alkyl phenolic resin and the wet slip resistance of polyacrylic acid resin, nano-cellulose and EVA / POE / EBA polymer cross-linking foaming, solves the problem of the existing EVA foamed shoe sole slip resistance. It is feasible.

[0104] Compared with the existing EVA foamed shoe sole, the present application optimizes the multi-component polymer matrix, innovatively combines EVA, POE, EBA, SEBS and BIMSM and other materials, and fully utilizes their respective characteristics: EVA provides uniform pore structure and foaming performance; POE enhances the resilience and flexibility of the foamed shoe sole; EBA improves the anti-shrinkage, compression resistance and wet slip resistance of the foamed shoe sole; SEBS improves the dry slip resistance of the foamed shoe sole; BIMSM significantly improves the shock absorption and slip resistance of the foamed shoe sole in wet slip environment. Through the synergistic effect of multiple components, the foamed shoe sole is light, soft, high-bounce, shock-absorbing, wear-resistant and slip-resistant.

[0105] The present application preferably introduces p-tert-butyl phenol formaldehyde resin as a tackifier, significantly improves the interfacial adhesion and cohesive strength through the flow carrier effect, bridging effect and hydrogen bond network strengthening, improves the slip resistance and flexibility of the sole in dry environment; by using polyacrylic acid resin to regulate the hydrophilic interface, by quickly adsorbing water molecules to destroy the water film between the sole and the road surface, the friction coefficient in wet and slippery environment is greatly improved, and the compatibility of polyacrylic acid resin and EBA and other materials is improved to form a stable interpenetrating network structure; using high-strength, high-specific surface area, high-adsorption and strong hydrophilic nanohydrophilic filler nanocellulose, which contains hydroxyl / carboxyl groups, is beneficial to form strong hydrogen bond with acrylic resin, etc. to improve the mechanical properties and wet skid resistance of the foamed sole, which has technical innovation.

[0106] The prepared EVA foaming material achieves excellent level in static dry sliding, static wet sliding, dynamic dry sliding and dynamic wet sliding performance, such as static dry sliding ≥1.0, static wet sliding ≥0.8, dynamic dry sliding ≥0.8, dynamic wet sliding ≥0.5, while maintaining light weight, softness, high elasticity and wear resistance, solving the problem of insufficient skid resistance of existing EVA foaming sole, realizing the breakthrough of comprehensive performance, especially suitable for indoor and outdoor wet sports scenes, significantly improving the sports safety.

[0107] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments and its various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. An EVA foamed shoe sole material, characterized by, is prepared by foaming an EVA compound, which comprises, by weight parts: 40-60 parts of ethylene-vinyl acetate copolymer, 10-20 parts of random polyolefin elastomer, 5-20 parts of ethylene-butyl acrylate polymer, 5-20 parts of hydrogenated styrene-ethylene / butylene-styrene block copolymer, and 5-20 parts of brominated isobutylene-p-methylstyrene copolymer elastomer; 2-5 parts of tackifier; 3-6 parts of wet skid resistance agent; 3-5 parts of nano-hydrophilic filler; 3-5 parts of wear-resistant agent; 2.5-3.5 parts of foaming agent; and crosslinking agent and active agent; the tackifier is alkyl phenolic resin; the wet skid resistance agent is polyacrylic acid resin; and the nano-hydrophilic filler is nano-cellulose.

2. The EVA foamed shoe sole material according to claim 1, characterized in that, The VA content of the ethylene-vinyl acetate copolymer is 25-35 wt%; and / or, the acrylic structure content of the ethylene-butyl acrylate polymer is 20-35 wt%.

3. The EVA foamed shoe sole material according to claim 1, characterized in that, The vinyl content of the hydrogenated styrene-ethylene / butylene-styrene block copolymer is 3-5 wt%; and / or, the bromine content of the brominated isobutylene-p-methylstyrene copolymer elastomer is 1-3 wt%.

4. The EVA foamed shoe sole material according to any one of claims 1 to 3, characterized in that, The wear-resistant agent is vinyl silicone oil with a room temperature viscosity of 800-100,000 mpa.s.

5. The EVA foamed shoe sole material according to any one of claims 1 to 3, characterized in that, The foaming agent is one or more of azodicarbonamide, expanded microspheres and 4,4-oxadiazolidine; and / or, the EVA compound comprises 0.4-0.6 parts of peroxide crosslinking agent.

6. The EVA foamed shoe sole material according to any one of claims 1 to 3, characterized in that, The active agent comprises: zinc oxide 1.0-1.5 parts, stearic acid 0.5-1.0 parts and zinc stearate 0.5-1.0 parts.

7. The EVA foamed shoe sole material according to any one of claims 1 to 3, characterized in that, The EVA foamed shoe sole material satisfies at least one of the following: a resilience rate ≥ 60%; a density of 0.11-0.19 g / cm 3 ; dry sliding ≥ 0.8; wet sliding ≥ 0.

5.

8. A method for preparing the EVA foamed shoe sole material of any one of claims 1-7, comprising the following steps: The EVA compound is subjected to a one-shot foaming process or a two-shot foaming process to obtain the EVA foamed shoe sole material.

9. The preparation method according to claim 8, characterized in that, In the one-shot foaming process and the two-shot foaming process, the EVA compound is subjected to mixing and granulation before foaming.

10. An athletic shoe comprising the EVA foamed shoe sole material of any one of claims 1-7.

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