Wear-resistant non-slip EVA (ethylene-vinyl acetate) sole material and preparation process thereof

Abstract

The invention relates to the technical field of EVA (Ethylene Vinyl Acetate), and discloses a wear-resistant non-slip EVA sole material and a preparation process thereof. The wear-resistant non-slip EVA sole material comprises the following components in parts by weight: 100 parts of an ethylene-vinyl acetate copolymer, 1-4 parts of nylon fibers, 0.2-1 part of a VA-SSS-based polyamide copolymer, 0.5-0.8 part of a cross-linking agent, 2.2-3 parts of a foaming agent and the like. The VA-SSS-based polyamide copolymer can improve the compatibility of nylon fibers in EVA, so that the nylon fibers have a better reinforcing effect, meanwhile, the interfacial acting force between montmorillonite and EVA is improved, the dispersity of montmorillonite is improved, the montmorillonite is not prone to agglomeration in an EVA sole material, the uniformly dispersed montmorillonite has a good reinforcing effect, and the EVA sole material can be used as an EVA sole material. The wear resistance, slip resistance and tear strength of the material are improved at present.

Description

Technical Field

[0001] The present invention relates to the technical field of EVA, and specifically to a wear-resistant and anti-slip EVA sole material and its preparation process. Background Art

[0002] Currently, the main sole materials are foaming materials such as EVA, polyvinyl chloride, and polyurethane. Among them, ethylene-vinyl acetate copolymer (EVA) has good foaming properties, good water resistance, non-toxic and odorless, and excellent resilience, and is widely used in shoe materials, hot melt adhesives, films, sound insulation materials, etc. Traditional EVA has poor wear resistance and mechanical properties such as tear strength. Therefore, it is necessary to improve the wear resistance, anti-slip, and mechanical strength of EVA to make EVA have better practical applications in sole materials and other aspects.

[0003] Montmorillonite is a natural silicate mineral with a wide source and low cost. After modification, montmorillonite has good dispersion properties and is widely used in polymer materials such as plastics, fibers, and rubbers, which can improve the impact strength, wear resistance, heat resistance, etc. of the materials. Currently, the modifiers for montmorillonite include sodium dodecylbenzenesulfonate, silane coupling agent, polyacrylic acid, etc. Chinese Patent CN110591214B discloses a fluorinated organic montmorillonite-modified EVA foaming material and its preparation method, in which fluorinated organic montmorillonite, compatibilizers such as styrenic thermoplastic elastomer and glycidyl methacrylate-grafted EVA are blended and foamed with EVA to obtain a foamed product with excellent wear resistance and anti-slip performance. However, the preparation method of the fluorinated organic montmorillonite in this patent is relatively complex and does not improve the tear strength of the EVA material. Nylon fiber is a synthetic fiber with good wear resistance and high mechanical strength. The present invention aims to use montmorillonite and nylon fiber to improve the mechanical strength, wear resistance, etc. of the EVA sole material. Summary of the Invention

[0004] The present invention solves the problems of poor mechanical strength, wear resistance, etc. of the EVA sole material.

[0005] The technical solution of the present invention: A wear-resistant and anti-slip EVA sole material, by weight, the wear-resistant and anti-slip EVA sole material includes 100 parts of ethylene-vinyl acetate copolymer, 1-4 parts of nylon fiber, 0.2-1 part of VA-SSS-based polyamide copolymer, 2-8 parts of filler, 0.6-1.2 parts of auxiliary agent, 0.5-0.8 part of crosslinking agent, 2.2-3 parts of foaming agent, 0.6-0.8 part of stearic acid, and 0.4-0.7 part of zinc stearate.

[0006] Further, the filler is montmorillonite, the auxiliary agent is zinc oxide, the crosslinking agent is dicumyl peroxide, and the foaming agent is azodicarbonamide.

[0007] Further, the preparation process of the wear-resistant and anti-slip EVA sole material is as follows: Add ethylene-vinyl acetate copolymer, nylon fiber, VA-SSS-based polyamide copolymer, filler, auxiliary agent, stearic acid, and zinc stearate into an open mill, control the roller temperature at 90 - 100 °C, add a cross-linking agent after mixing, and continue mixing; then add a foaming agent, mix and take out the sheet; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 175 - 185 °C, a pressure of 15 - 20 MPa, and a time of 6 - 8 min, discharge the material, and cool to obtain the wear-resistant and anti-slip EVA sole material.

[0008] Further, the preparation process of the VA-SSS-based polyamide copolymer is as follows:

[0009] (1) By weight fraction, add toluene, 100 parts of vinyl acetate (VA), 10 - 25 parts of sodium 4-styrenesulfonate (SSS), 1.6 - 1.8 parts of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate (the structural formula is ), 0.14 - 0.2 parts of azobisisobutyronitrile into a reaction vessel, heat to 60 - 75 °C in a nitrogen atmosphere, react for 12 - 18 h, add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain carboxyl-terminated (vinyl acetate-sodium styrenesulfonate)

[0010] copolymer. The reaction formula is as follows:

[0011]

[0012] (2) By weight, add N-methylpyrrolidone, 100 parts of carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer into a reaction vessel, stir and then add 6.4 - 8.5 parts of diamine compound, 31 - 35 parts of pyridine, 26 - 32 parts of triphenyl phosphite, 15 - 18 parts of calcium chloride, stir and react at 110 - 130 °C in a nitrogen atmosphere for 18 - 24 h, add ethanol to dilute the solution, filter, wash with ethanol and water, and dry to obtain the VA-SSS-based polyamide copolymer. The reaction formula is:

[0013]

[0014] Further, the diamine compound is 1,4-butanediamine, 1,5-pentanediamine or 1,6-hexanediamine.

[0015] Technical effect: In the present invention, S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate is used as a RAFT chain transfer agent, and azobisisobutyronitrile is used as an initiator to initiate the reversible addition-fragmentation chain transfer polymerization reaction of vinyl acetate and sodium 4-styrenesulfonate to obtain a carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer. Then, triphenyl phosphite and pyridine are used as condensing agents to carry out amidation polymerization reaction with 1,6-hexanediamine diamine compounds and other substances to obtain a VA-SSS-based polyamide copolymer. Finally, montmorillonite and nylon fiber are used as reinforcing agents, ethylene-vinyl acetate copolymer EVA is used as a foaming base material, dicumyl peroxide is used as a crosslinking agent, and azodicarbonamide is used as a foaming agent. Through blending and foaming, a wear-resistant and anti-slip EVA sole material is obtained.

[0016] The main chain of the VA-SSS-based polyamide copolymer of the present invention contains a polyvinyl acetate block molecular chain identical to that of EVA. At the same time, the main chain contains an amide bond structural unit, which has a similar polarity to the polyamide molecular chain of nylon fiber, enabling the VA-SSS-based polyamide copolymer to act as a compatibilizer, improving the compatibility of nylon fiber in EVA, making the nylon fiber play a better reinforcing role, and being conducive to improving the wear resistance, anti-slip performance, and mechanical strength of the EVA sole material.

[0017] The side chain of the VA-SSS-based polyamide copolymer of the present invention contains a sodium sulfonate group, which can form an interaction with the surface of montmorillonite, acting as a dispersant. At the same time, it improves the interfacial force between montmorillonite and EVA, and improves the dispersibility of montmorillonite. Agglomeration is not likely to occur in the EVA sole material. The uniformly dispersed montmorillonite has a good strengthening effect, further improving the wear resistance, anti-slip performance, and mechanical strength of the material, showing a higher dry friction coefficient and tear strength, and at the same time reducing the wear volume of the sole material. Specific embodiments

[0018] In order to make the purpose, technical solutions, and beneficial effects of the present invention clearer, the preferred embodiments of the present invention will be described in detail below to facilitate understanding by those skilled in the art.

[0019] The following ethylene-vinyl acetate copolymer, model LG 28150, is purchased from Shanghai Oushuo Plastic Co., Ltd. Montmorillonite, with an average particle size of 1250 mesh, is purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd. Nylon fiber, with a length of 6 mm, is from Nantong Yiheng New Materials Technology Co., Ltd.

[0020] Example 1:

[0021] (1) Add 80 mL of toluene, 20 g of vinyl acetate, 3.5 g of sodium 4-styrenesulfonate, 0.32 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate, and 35 mg of azobisisobutyronitrile to the reaction vessel. Under a nitrogen atmosphere, heat to 75 °C and react for 12 h. Add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain a carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer.

[0022] (2) Add 250 mL of N-methylpyrrolidone and 20 g of the carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer to the reaction vessel. After stirring, add 1.7 g of 1,6-hexanediamine, 6.7 g of pyridine, 5.9 g of triphenyl phosphite, and 3.2 g of calcium chloride. Stir and react at 120 °C for 24 h under a nitrogen atmosphere. Add ethanol to dilute the solution, filter, wash with ethanol and water, and dry to obtain a VA-SSS-based polyamide copolymer.

[0023] (3) Add 5 kg of ethylene-vinyl acetate copolymer, 50 g of nylon fiber, 10 g of VA-SSS-based polyamide copolymer, 100 g of filler montmorillonite, 48 g of auxiliary agent zinc oxide, 40 g of stearic acid, and 20 g of zinc stearate to the open mill. Control the roll temperature at 100 °C. After mixing, add 34 g of crosslinking agent dicumyl peroxide and continue mixing; then add 110 g of foaming agent azodicarbonamide, mix and sheet out; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min. Discharge and cool to obtain a wear-resistant and anti-slip EVA sole material.

[0024] Comparative Example 1. The difference between this comparative example and Example 1 is that nylon fiber and VA-SSS-based polyamide copolymer are not added.

[0025] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 100 g of filler montmorillonite, 48 g of auxiliary agent zinc oxide, 40 g of stearic acid, and 20 g of zinc stearate to the open mill. Control the roll temperature at 100 °C. After mixing, add 34 g of crosslinking agent dicumyl peroxide and continue mixing; then add 110 g of foaming agent azodicarbonamide, mix and sheet out; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min. Discharge and cool to obtain an EVA sole material.

[0026] Comparative Example 2. The difference between this comparative example and Example 1 is that nylon fiber is not added.

[0027] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 10 g of VA-SSS-based polyamide copolymer, 100 g of filler montmorillonite, 48 g of zinc oxide as an additive, 40 g of stearic acid, and 20 g of zinc stearate into an open mill, control the roll temperature at 100 °C, after mixing, add 34 g of dicumyl peroxide as a crosslinking agent, and continue mixing; then add 110 g of azodicarbonamide as a foaming agent, mix and then take out the sheet; finally, perform compression molding and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min, discharge the material, and cool to obtain an EVA sole material.

[0028] Comparative Example 3: The difference between this comparative example and Example 1 is that montmorillonite and VA-SSS-based polyamide copolymer are not added.

[0029] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 50 g of nylon fiber, 48 g of zinc oxide as an additive, 40 g of stearic acid, and 20 g of zinc stearate into an open mill, control the roll temperature at 100 °C, after mixing, add 34 g of dicumyl peroxide as a crosslinking agent, and continue mixing; then add 110 g of azodicarbonamide as a foaming agent, mix and then take out the sheet; finally, perform compression molding and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min, discharge the material, and cool to obtain an EVA sole material.

[0030] Comparative Example 4: The difference between this comparative example and Example 1 is that montmorillonite is not added.

[0031] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 50 g of nylon fiber, 10 g of VA-SSS-based polyamide copolymer, 48 g of zinc oxide as an additive, 40 g of stearic acid, and 20 g of zinc stearate into an open mill, control the roll temperature at 100 °C, after mixing, add 34 g of dicumyl peroxide as a crosslinking agent, and continue mixing; then add 110 g of azodicarbonamide as a foaming agent, mix and then take out the sheet; finally, perform compression molding and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min, discharge the material, and cool to obtain an EVA sole material.

[0032] Comparative Example 5: The difference between this comparative example and Example 1 is that VA-SSS-based polyamide copolymer is not added.

[0033] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 50 g of nylon fiber, 100 g of filler montmorillonite, 48 g of zinc oxide as an additive, 40 g of stearic acid, and 20 g of zinc stearate into an open mill, control the roll temperature at 100 °C, after mixing, add 34 g of dicumyl peroxide as a crosslinking agent, and continue mixing; then add 110 g of azodicarbonamide as a foaming agent, mix and then take out the sheet; finally, perform compression molding and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min, discharge the material, and cool to obtain an EVA sole material.

[0034] Comparative Example 6: The difference between this comparative example and Example 1 is that when preparing the copolymer, styrene is used instead of sodium 4-styrenesulfonate.

[0035] (1) Add 80 mL of toluene, 20 g of vinyl acetate, 3.5 g of styrene, 0.32 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate, and 35 mg of azobisisobutyronitrile to a reaction vessel. Under a nitrogen atmosphere, heat to 75 °C and react for 12 h. Add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain a carboxyl-terminated (vinyl acetate-styrene) copolymer.

[0036] (2) Add 250 mL of N-methylpyrrolidone and 20 g of the carboxyl-terminated (vinyl acetate-styrene) copolymer to a reaction vessel. After stirring, add 1.7 g of 1,6-hexanediamine, 6.7 g of pyridine, 5.9 g of triphenyl phosphite, and 3.2 g of calcium chloride. Under a nitrogen atmosphere, stir and react at 120 °C for 24 h. Add ethanol to dilute the solution, filter, wash with ethanol and water, and dry to obtain a VA-St-based polyamide copolymer.

[0037] (3) Add 5 kg of ethylene-vinyl acetate copolymer, 50 g of nylon fiber, 10 g of VA-SSS-based polyamide copolymer, 100 g of filler montmorillonite, 48 g of auxiliary agent zinc oxide, 40 g of stearic acid, and 20 g of zinc stearate to an open mill. Control the roll temperature at 100 °C. After mixing, add 34 g of cross-linking agent dicumyl peroxide and continue mixing; then add 110 g of blowing agent azodicarbonamide, mix and sheet out; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min, discharge, and cool to obtain an EVA sole material.

[0038] Comparative Example 7: The difference between this comparative example and Example 1 is that when preparing the copolymer, sodium 4-styrenesulfonate is used instead of vinyl acetate.

[0039] (1) Add 80 mL of toluene, 23.5 g of sodium 4-styrenesulfonate, 0.32 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate, and 35 mg of azobisisobutyronitrile to a reaction vessel. Under a nitrogen atmosphere, heat to 75 °C and react for 12 h. Add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain a carboxyl-terminated sodium styrenesulfonate copolymer.

[0040] (2) Add 250 mL of N-methylpyrrolidone and 20 g of carboxyl-terminated styrene sulfonate copolymer into the reaction vessel. After stirring, add 1.7 g of 1,6-hexanediamine, 6.7 g of pyridine, 5.9 g of triphenyl phosphite, and 3.2 g of calcium chloride. Stir and react at 120 °C for 24 h in a nitrogen atmosphere. Dilute the solution with ethanol, filter, wash with ethanol and water, and dry to obtain the SSS-based polyamide copolymer.

[0041] (3) Add 5 kg of ethylene-vinyl acetate copolymer, 50 g of nylon fiber, 10 g of SSS-based polyamide copolymer, 100 g of filler montmorillonite, 48 g of zinc oxide as an additive, 40 g of stearic acid, and 20 g of zinc stearate into the open mill. Control the roll temperature at 100 °C. After mixing, add 34 g of dicumyl peroxide as a crosslinking agent and continue mixing; then add 110 g of azodicarbonamide as a foaming agent, mix and sheet out; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 180 °C, a pressure of 15 MPa, and a time of 8 min. Discharge and cool to obtain the EVA sole material.

[0042] Example 2:

[0043] (1) Add 80 mL of toluene, 20 g of vinyl acetate, 5 g of sodium 4-styrenesulfonate, 0.34 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate, and 40 mg of azobisisobutyronitrile into the reaction vessel. Heat to 60 °C in a nitrogen atmosphere and react for 18 h. Dilute the solution with ethanol, filter, wash with ethanol, and dry to obtain the carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer.

[0044] (2) Add 250 mL of N-methylpyrrolidone and 20 g of carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer into the reaction vessel. After stirring, add 1.28 g of 1,4-butanediamine, 7 g of pyridine, 5.2 g of triphenyl phosphite, and 3 g of calcium chloride. Stir and react at 130 °C for 18 h in a nitrogen atmosphere. Dilute the solution with ethanol, filter, wash with ethanol and water, and dry to obtain the VA-SSS-based polyamide copolymer.

[0045] (3) Add 5 kg of ethylene-vinyl acetate copolymer, 120 g of nylon fiber, 10 g of VA-SSS-based polyamide copolymer, 250 g of filler montmorillonite, 60 g of zinc oxide as an additive, 33 g of stearic acid, and 25 g of zinc stearate into the open mill. Control the roll temperature at 90 °C. After mixing, add 25 g of dicumyl peroxide as a crosslinking agent and continue mixing; then add 150 g of azodicarbonamide as a foaming agent, mix and sheet out; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 175 °C, a pressure of 20 MPa, and a time of 8 min. Discharge and cool to obtain the wear-resistant and anti-slip EVA sole material.

[0046] Example 3:

[0047] (1) Add 70 mL of toluene, 20 g of vinyl acetate, 2 g of sodium 4-styrenesulfonate, 0.32 g of S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate, and 28 mg of azobisisobutyronitrile to a reaction vessel. Under a nitrogen atmosphere, heat to 65 °C and react for 12 h. Add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain a carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer.

[0048] (2) Add 250 mL of N-methylpyrrolidone and 20 g of the carboxyl-terminated (vinyl acetate-sodium styrenesulfonate) copolymer to a reaction vessel. After stirring, add 1.52 g of 1,5-pentanediamine, 6.2 g of pyridine, 6.4 g of triphenyl phosphite, and 3.6 g of calcium chloride. Under a nitrogen atmosphere, stir and react at 110 °C for 24 h. Add ethanol to dilute the solution, filter, wash with ethanol and water, and dry to obtain a VA-SSS-based polyamide copolymer.

[0049] (3) Add 5 kg of ethylene-vinyl acetate copolymer, 200 g of nylon fiber, 10 g of VA-SSS-based polyamide copolymer, 400 g of filler montmorillonite, 30 g of zinc oxide as an additive, 30 g of stearic acid, and 25 g of zinc stearate to an open mill. Control the roll temperature at 90 °C. After mixing, add 40 g of dicumyl peroxide as a cross-linking agent and continue mixing; then add 136 g of azodicarbonamide as a foaming agent, mix and sheet out; finally, perform compression molding and foaming in a vulcanizer at a temperature of 185 °C, a pressure of 20 MPa, and a time of 6 min. Discharge and cool to obtain a wear-resistant and non-slip EVA sole material.

[0050] Example 4:

[0051] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 120 g of nylon fiber, 30 g of VA-SSS-based polyamide copolymer (prepared by the process of Example 2), 250 g of filler montmorillonite, 60 g of zinc oxide as an additive, 33 g of stearic acid, and 25 g of zinc stearate to an open mill. Control the roll temperature at 90 °C. After mixing, add 25 g of dicumyl peroxide as a cross-linking agent and continue mixing; then add 150 g of azodicarbonamide as a foaming agent, mix and sheet out; finally, perform compression molding and foaming in a vulcanizer at a temperature of 175 °C, a pressure of 20 MPa, and a time of 8 min. Discharge and cool to obtain a wear-resistant and non-slip EVA sole material.

[0052] Example 5:

[0053] (1) Add 5 kg of ethylene-vinyl acetate copolymer, 120 g of nylon fiber, 50 g of VA-SSS-based polyamide copolymer (prepared by the process of Example 2), 250 g of filler montmorillonite, 60 g of auxiliary agent zinc oxide, 33 g of stearic acid, and 25 g of zinc stearate into an open mill. Control the roller temperature at 90 °C. After mixing, add 25 g of cross-linking agent dicumyl peroxide and continue mixing. Then add 150 g of foaming agent azodicarbonamide, mix and take out the sheet. Finally, perform mold pressing and foaming in a vulcanizer at a temperature of 175 °C, a pressure of 20 MPa, and a time of 8 min. Discharge the material and cool it to obtain a wear-resistant and anti-slip EVA sole material.

[0054] The wear resistance of the EVA sole material is tested according to the method specified in the national standard GB / T 9867-2008. The lower the abrasion volume, the better the wear resistance. The anti-slip performance is tested according to the method specified in GB / T 3903.6-2017. The larger the friction coefficient, the better the anti-slip performance. The tear strength is tested according to the national standard GB / T 10808-2006.

[0055] Table 1 Performance Test of EVA Sole Material

[0056]

[0057]

[0058] As can be seen from the above table, compared with Comparative Example 5, in Example 1, the addition of VA-SSS-based polyamide copolymer, the copolymer contains the same polyvinyl acetate block molecular chain as EVA, and at the same time contains amide bond structural units, which has a similar polarity to the polyamide molecular chain of nylon fiber, enabling the VA-SSS-based polyamide copolymer to act as a compatibilizer, improving the compatibility of nylon fiber in EVA, making the nylon fiber play a better reinforcing role, being beneficial to improving the wear resistance, anti-slip performance, and mechanical strength of the EVA sole material. And the side chain of the VA-SSS-based polyamide copolymer contains sodium sulfonate groups, which can form an interaction with the surface of montmorillonite, acting as a dispersant, while improving the interfacial interaction between montmorillonite and EVA, and improving the dispersibility of montmorillonite. It is not easy to agglomerate in the EVA sole material. The uniformly dispersed montmorillonite has a good strengthening effect, further improving the wear resistance, anti-slip performance, and mechanical strength of the material, showing a higher dry friction coefficient and tear strength, while reducing the abrasion volume of the material.

[0059] In Comparative Example 1, only montmorillonite was added. The compatibility between montmorillonite and EVA is poor, the dispersibility is not good, and the strengthening effect is low, resulting in a large abrasion volume of the EVA sole material, a low dry friction coefficient, poor wear resistance and anti-slip performance, and a low tear strength.

[0060] Compared with Comparative Example 1, VA-SSS-based polyamide copolymer was added in Comparative Example 2. Its side chain contains sodium sulfonate groups, which can form interactions with the surface of montmorillonite, acting as a dispersant. At the same time, it improves the interfacial force between montmorillonite and EVA and enhances the dispersibility of montmorillonite. The uniformly dispersed montmorillonite has a good reinforcing effect, which can improve the wear resistance, anti-slip and tear strength of the sole material.

[0061] In Comparative Example 3, only nylon fibers were added. Its compatibility with EVA is poor and the reinforcing effect is not good, resulting in poor wear resistance, anti-slip and tear strength of the sole material.

[0062] Compared with Comparative Example 3, VA-SSS-based polyamide copolymer was added in Comparative Example 4, which can act as a compatibilizer, improve the compatibility of nylon fibers in EVA, make the nylon fibers play a better reinforcing role, and is beneficial to improving the properties such as wear resistance and mechanical strength of EVA sole materials.

[0063] In Comparative Example 6, styrene was used instead of 4-styrene sulfonate sodium. The side chains of the obtained carboxyl-terminated (vinyl acetate-styrene) copolymer and VA-St-based polyamide copolymer do not contain sodium sulfonate groups, cannot form interactions with the surface of montmorillonite, cannot act as a dispersant, do not improve the interfacial force between montmorillonite and EVA, the reinforcing effect of montmorillonite is not good, and the wear resistance, anti-slip and tear strength of the sole material are poor.

[0064] In Comparative Example 7, vinyl acetate was replaced by 4-styrene sulfonate sodium. The main chain of the obtained carboxyl-terminated styrene sulfonate sodium copolymer and SSS-based polyamide copolymer does not contain polyvinyl acetate block molecular chains, cannot act as a compatibilizer, and cannot improve the compatibility between nylon fibers, montmorillonite and EVA, resulting in poor wear resistance, anti-slip and tear strength of the sole material.

Claims

1. A wear-resistant and anti-slip EVA sole material, characterized in that, By weight parts, the wear-resistant and anti-slip EVA sole material comprises 100 parts of ethylene-vinyl acetate copolymer, 1-4 parts of nylon fiber, 0.2-1 part of VA-SSS-based polyamide copolymer, 2-8 parts of filler, 0.6-1.2 parts of additive, 0.5-0.8 part of cross-linking agent, 2.2-3 parts of foaming agent, 0.6-0.8 part of stearic acid, and 0.4-0.7 part of zinc stearate; The preparation process of the VA-SSS-based polyamide copolymer is as follows: Add N-methylpyrrolidone and a carboxyl-terminated (vinyl acetate-sodium styrene sulfonate) copolymer into a reaction vessel. After stirring, add a diamine compound, pyridine, triphenyl phosphite, and calcium chloride, and stir and react in a nitrogen atmosphere. Add ethanol to dilute the solution, filter, wash with ethanol and water, and dry to obtain the VA-SSS-based polyamide copolymer.

2. The wear-resistant and anti-slip EVA sole material according to claim 1, characterized in that, By weight parts, the temperature of the reaction is 110-130 °C, and the reaction time is 18-24 h.

3. The wear-resistant and anti-slip EVA sole material according to claim 1, characterized in that, By weight parts, the dosage of the carboxyl-terminated (vinyl acetate-sodium styrene sulfonate) copolymer is 100 parts, the diamine compound is 6.4-8.5 parts, pyridine is 31-35 parts, triphenyl phosphite is 26-32 parts, and calcium chloride is 15-18 parts.

4. The wear-resistant and anti-slip EVA sole material according to claim 3, characterized in that, By weight parts, the diamine compound is 1,4-butanediamine, 1,5-pentanediamine, or 1,6-hexanediamine.

5. The wear-resistant and anti-slip EVA sole material according to claim 3, characterized in that, The preparation process of the carboxyl-terminated (vinyl acetate-sodium styrene sulfonate) copolymer is as follows: Add toluene, vinyl acetate, 4-sodium styrene sulfonate, S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate, and azobisisobutyronitrile into a reaction vessel. Under a nitrogen atmosphere, heat to 60-75 °C and react for 12-18 h. Add ethanol to dilute the solution, filter, wash with ethanol, and dry to obtain the carboxyl-terminated (vinyl acetate-sodium styrene sulfonate) copolymer.

6. The wear-resistant and anti-slip EVA sole material according to claim 5, characterized in that, By weight parts, the dosage of vinyl acetate is 100 parts, 4-sodium styrene sulfonate is 10-25 parts, S,S'-bis(α,α'-methyl-α"-acetic acid) trithiocarbonate is 1.6-1.8 parts, and azobisisobutyronitrile is 0.14-0.2 part.

7. The wear-resistant and anti-slip EVA sole material according to claim 1, characterized in that The filler is montmorillonite, and the additive is zinc oxide.

8. The wear-resistant and anti-slip EVA sole material according to claim 1, characterized in that, The cross-linking agent is dicumyl peroxide, and the foaming agent is azodicarbonamide.

9. A preparation process of the wear-resistant and anti-slip EVA sole material according to any one of claims 1-8, characterized in that, The preparation process is as follows: Add ethylene-vinyl acetate copolymer, nylon fiber, VA-SSS-based polyamide copolymer, filler, additive, stearic acid, and zinc stearate into an open mill, control the roll temperature at 90-100 °C, mix, add the cross-linking agent, and continue mixing; then add the foaming agent, mix and sheet out; finally, perform mold pressing and foaming in a vulcanizer at a temperature of 175-185 °C, a pressure of 15-20 MPa, and a time of 6-8 min, discharge, and cool to obtain the wear-resistant and anti-slip EVA sole material.

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