High-wear-resistance, non-slip and high-adhesion ejection rubber as well as preparation method and application thereof

Abstract

The invention provides injection rubber with high wear resistance, slip resistance and high binding power as well as a preparation method and application of the injection rubber. The injection rubber is prepared from the following raw materials in parts by weight: 20 to 35 parts of modified rubber master batch, 40 to 60 parts of ethylene-vinyl acetate, 10 to 20 parts of sodium surlyn resin, 5 to 10 parts of maleic anhydride grafted EVA (Ethylene Vinyl Acetate), 6 to 10 parts of silica gel microspheres, 6 to 8 parts of wear-resistant agent, 1 to 2 parts of lubricant and 0.3 to 0.5 part of cross-linking agent. The modified rubber master batch is obtained by carrying out graft modification on a mixture of silicone rubber and ethylene propylene diene monomer by maleic anhydride; the content of a non-conjugated diene monomer in the ethylene propylene diene monomer is 4.5-8%. The rubber outsole provided by the invention has excellent wear resistance and slip resistance, solves the technical bottlenecks of poor adhesion and insufficient slip resistance of the existing light injection rubber outsole in the industry, and has a great market prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of shoe sole materials, and particularly relates to a high-wear-resistance and high-adhesion injection rubber, a preparation method and application thereof. BACKGROUND

[0002] With more and more people paying attention to health, various sports such as basketball, running, slow walking and hiking are deeply loved by people, and the functional requirements for sports shoes are also higher and higher. In particular, the rubber outsole is particularly important in wear resistance and slip resistance because it directly contacts the ground. At present, the rubber outsole commonly used in the industry is mainly various types of rubber such as butadiene rubber / natural rubber / styrene butadiene rubber / brominated butyl rubber / isoprene rubber / acrylonitrile rubber, which is molded and vulcanized. On the one hand, the density of this type of rubber outsole is usually greater than 1.1 g / cm 3 , and the weight is heavy; on the other hand, this type of rubber outsole is prepared by a process of internal mixing-opening-extruding-cutting-molding vulcanization, which not only has complicated procedures and low production efficiency, but also produces a large amount of waste in the cutting process and is prone to produce burrs in the molding vulcanization process, resulting in waste and pollution.

[0003] In order to improve the above two points, many factories in the industry prepare light and wear-resistant rubber outsoles by injection molding process. The injection rubber is mainly prepared by using EVA as the main matrix, and adding ethylene propylene terpolymer, brominated butyl rubber, styrene elastomer and wear-resistant agent. These technical solutions mainly use wear-resistant agents to improve the wear resistance of the rubber sole, which can meet the requirements of density 0.8±0.2 g / cm 3 and DIN wear resistance ≤40 mm 3 . However, due to the addition amount of EVA being greater than 40 parts and the content of wear-resistant agent being 5-10 parts, the prepared rubber sole has poor slip resistance, and the general dynamic wet slip is ≤0.25. In addition, the ethylene propylene terpolymer / styrene elastomer / wear-resistant agent in the formula is a non-polar polymer, which leads to poor adhesion of the entire rubber sole (adhesion strength ≤20 N / cm) and high risk of opening. SUMMARY

[0004] The application aims to provide a high-wear-resistance and high-adhesion injection rubber, a preparation method and application thereof. The injection rubber has excellent wear resistance, slip resistance and adhesion.

[0005] The application provides a high-wear-resistance and high-adhesion injection rubber, which comprises the following raw materials in parts by weight:

[0006] Modified rubber master batch 20~35 parts, ethylene-vinyl acetate 40~60 parts, sodium-based sarin resin 10~20 parts, maleic anhydride grafted EVA 5~10 parts, silica microspheres 6~10 parts, wear-resistant agent 6~8 parts, lubricant 1~2 parts, crosslinking agent 0.3~0.5 parts;

[0007] The modified rubber master batch is obtained by grafting modification of a mixture of maleic anhydride and silicone rubber and ethylene-propylene-diene rubber;

[0008] The mass fraction of non-conjugated diene monomer in the ethylene-propylene-diene rubber is 4.5~8%.

[0009] Preferably, the modified rubber master batch is prepared according to the following steps:

[0010] The silicone rubber 30~70 parts, ethylene-propylene-diene rubber 30~70 parts, maleic anhydride 4~6 parts, hydroxyl silane coupling agent 2~3 parts, initiator 0.4~0.6 parts, flow aid 0.8~1 parts and white carbon black 18~20 parts are mixed and then subjected to melting, extrusion granulation and drying to obtain the modified rubber master batch.

[0011] Preferably, the temperature of the mixing is 70~90℃, and the mixing time is 60~80min;

[0012] The temperature of the extrusion granulation is 150~70℃.

[0013] Preferably, the density of the silica microspheres is 0.1~0.5 g / cm³, the particle size is 30~60μm, and the specific surface area is 200~500m 2 / g.

[0014] The present application provides a preparation method of the high-wear-resistance non-slip high-adhesion injection rubber as described above, comprising the following steps:

[0015] A) The modified rubber master batch, ethylene-vinyl acetate, sodium-based sarin resin and maleic anhydride grafted EVA are added into a banbury mixer, and heated for banburying, when the temperature is raised to 80~85℃, the silica microspheres and wear-resistant agent are added, and the temperature is continuously raised for mixing, when the temperature is raised to 90~95℃, the lubricant and crosslinking agent are added, and the temperature is continuously raised for mixing, when the temperature is raised to 100~105℃, the mixture is obtained;

[0016] B) The mixture is subjected to extrusion granulation to obtain a mixed master batch;

[0017] C) The mixed master batch is subjected to injection molding to obtain the high-wear-resistance non-slip high-adhesion injection rubber.

[0018] Preferably, in the step A), the mixing time of the modified rubber masterbatch, ethylene-vinyl acetate, sodium-based sarin resin and maleic anhydride grafted EVA after the internal mixer is 15-20 min, the mixing time of the silica microspheres and the wear-resistant agent is 5-8 min, and the mixing time of the lubricant and the crosslinking agent is 5-8 min.

[0019] Preferably, in the step B), the extrusion granulation is provided with four temperature zones, the first temperature zone is 92-97℃, the second temperature zone is 98-102℃, the third temperature zone is 103-106℃, and the fourth temperature zone is 107-113℃.

[0020] Preferably, in the step C), the feeding of the injection molding is provided with four temperature zones, the first temperature zone is 92-97℃, the second temperature zone is 98-102℃, the third temperature zone is 103-106℃, and the fourth temperature zone is 107-113℃.

[0021] Preferably, in the step C), the temperature of the injection molding is 175-185℃, and the vulcanization time of the injection molding is 220-280 s.

[0022] The present application provides a rubber sole prepared from the high wear-resistant and high adhesive force injection rubber described above.

[0023] The present application provides a high wear-resistant and high adhesive force injection rubber, which comprises the following raw materials in parts by weight: 20-35 parts of modified rubber masterbatch, 40-60 parts of ethylene-vinyl acetate, 10-20 parts of sodium-based sarin resin, 5-10 parts of maleic anhydride grafted EVA, 6-10 parts of silica microspheres, 6-8 parts of wear-resistant agent, 1-2 parts of lubricant, and 0.3-0.5 parts of crosslinking agent; the modified rubber masterbatch is obtained by grafting modification of a mixture of maleic anhydride and silicone rubber and ethylene-propylene-diene rubber; the content of non-conjugated diene monomer in the ethylene-propylene-diene rubber is 4.5-8%. The silicone rubber and the ethylene-propylene-diene rubber with high ethylene content are grafted and modified to prepare a rubber masterbatch, which is then organically combined with ethylene-vinyl acetate, sodium-based sarin resin, maleic anhydride grafted EVA, silica microspheres, wear-resistant agent, lubricant, crosslinking agent, etc. to prepare a rubber sole with a hardness of 65±3A, a density of 0.8±0.1 g / cm 3 , DIN wear resistance ≤30 mm 3 , dynamic dry slip ≥0.9, dynamic wet slip ≥0.6, adhesive strength ≥30 N / cm, tensile strength ≥20 MPa, and right-angle tear strength ≥40 N / cm. The rubber sole of the present application has excellent wear resistance and slip resistance, solves the technical bottleneck of poor adhesion and insufficient slip resistance of the existing light injection rubber sole in the industry, and has great market prospects. DETAILED DESCRIPTION

[0024] The application provides a high-wear-resistance, high-adhesion, high-slip-resistance and high-bonding-force injection rubber, which comprises the following raw materials in parts by weight:

[0025] 20-35 parts of modified rubber master batch, 40-60 parts of ethylene-vinyl acetate, 10-20 parts of sodium-based sarin resin, 5-10 parts of maleic anhydride grafted EVA, 6-10 parts of silica microspheres, 6-8 parts of wear-resistant agent, 1-2 parts of lubricant, and 0.3-0.5 parts of crosslinking agent.

[0026] The modified rubber master batch is obtained by grafting modification of a mixture of maleic anhydride and silicone rubber and ethylene-propylene-diene rubber.

[0027] The mass fraction of non-conjugated diene monomer in the ethylene-propylene-diene rubber is 4.5-8%.

[0028] In the application, the parts by weight of the modified rubber master batch is preferably 20-35 parts, more preferably 25-30 parts, such as 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, preferably a range value with any of the above-mentioned values as the upper limit or lower limit.

[0029] The application adopts a mixed rubber master batch of maleic anhydride grafted silicone rubber and high-ethylene-group-content ethylene-propylene-diene rubber. Silicone rubber exhibits excellent rubber feel and outstanding slip resistance due to the flexible silicon-oxygen bond (Si-O-Si) in its molecular structure. However, its wear resistance is relatively weak under repeated friction conditions. Ethylene-propylene-diene rubber is an elastomer polymerized from ethylene, propylene and non-conjugated diene monomer (ENB). The higher the content of the third monomer ENB, the more crosslinking points exist in the molecular chain, and the higher the crosslinking density of the vulcanized EPDM, thus better wear resistance and physical and mechanical properties are exhibited. However, EPDM is a non-polar polymer with low surface energy, resulting in a small friction coefficient between the material and the ground or other materials. On a wet and slippery ground, the slip resistance of ethylene-propylene-diene rubber is poor, and the rubber is prone to skidding. Both silicone rubber and EPDM rubber are non-polar materials with low surface energy and poor adhesion to other materials. In order to improve the adhesion of the two, the silicone rubber and EPDM rubber are grafted and modified by maleic anhydride (MAH). Maleic anhydride is grafted onto the molecular chains of silicone rubber and EPDM through free radical reaction to form modified silicone rubber and modified EPDM rubber with polar functional groups. These polar functional groups can significantly enhance the adhesion between silicone rubber and ethylene-propylene-diene rubber and other materials. The silicone rubber includes silicone rubber with a hardness of 40±5A, preferably NE-GT141; and the EPDM rubber includes a brand with a mass fraction of ENB of 4.5%-8%, preferably EPDM 5565.

[0030] In the present application, the modified rubber master batch is obtained by grafting modification of a mixture of silicone rubber and ethylene-propylene-diene rubber with maleic anhydride, and specifically comprises the following steps:

[0031] The silicone rubber 30-70 parts, the ethylene-propylene-diene rubber 30-70 parts, the maleic anhydride 4-6 parts, the hydroxyl silane coupling agent 2-3 parts, the initiator 0.4-0.6 parts, the flow aid 0.8-1 part and the white carbon black 18-20 parts are mixed in weight parts, and then melted, extruded, granulated and dried to obtain the modified rubber master batch.

[0032] In the present application, the hardness of the silicone rubber is preferably 40±5A, and the weight parts of the silicone rubber are preferably 30-70, more preferably 40-60, such as 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, preferably a range value with any of the above values as the upper limit or lower limit.

[0033] In the present application, the mass fraction of ENB in the ethylene-propylene-diene rubber is preferably 4.5-8%, more preferably 5-8%, and most preferably 6-7.5%, the number average molecular weight of the ethylene-propylene-diene rubber is preferably 180-220 thousand, and the weight parts of the ethylene-propylene-diene rubber are preferably 30-70, more preferably 40-60, such as 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, preferably a range value with any of the above values as the upper limit or lower limit.

[0034] In the present application, the weight parts of the maleic anhydride are preferably 4-6 parts, more preferably 4-5 parts. The hydroxyl silane coupling agent is preferably KH560, and the weight parts of the hydroxyl silane coupling agent are preferably 2-3 parts, more preferably 2.5-3 parts; the initiator is preferably benzoyl peroxide BPO, and the weight parts of the initiator are preferably 0.4-0.6 parts, more preferably 0.5-0.6 parts; the flow aid is preferably erucic acid amide, and the weight parts of the flow aid are preferably 0.8-1 parts, more preferably 0.9-1 parts; and the weight parts of the white carbon black are preferably 18-20 parts, more preferably 18-19 parts.

[0035] In the present application, the silicone rubber, the ethylene-propylene-diene rubber, the grafting agent maleic anhydride, the hydroxyl silane coupling agent, the initiator benzoyl peroxide BPO, the flow aid erucic acid amide and the white carbon black are weighed according to the above weight parts, and then poured into a high-speed mixer for stirring and mixing to obtain a mixture.

[0036] In the present application, the temperature of the mixing is preferably 70-90℃, more preferably 75-85℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, preferably a range with any of the above values as the upper or lower limit; the time of the mixing is preferably 60-80min, more preferably 65-75min, such as 60min, 65min, 70min, 75min, 80min, preferably a range with any of the above values as the upper or lower limit; the stirring speed of the mixing is preferably 900-1100rpm, more preferably 1000-1100rpm.

[0037] The mixture obtained after the mixing is subjected to high-temperature melt grafting modification by a twin-screw granulator, extrusion granulation and drying to obtain the modified rubber masterbatch.

[0038] In the present application, the temperature of the melting is preferably 160-180℃, more preferably 165-175℃, the temperature of the extrusion granulation is preferably 150-170℃, more preferably 160-165℃; the temperature of the drying is preferably 40-60℃, more preferably 50-55℃; the drying is preferably vacuum drying, and the time of the drying is preferably 2-3 hours.

[0039] In the present application, the mass fraction of the vinyl acetate in the ethylene-vinyl acetate is preferably 18-28%, specifically, in some embodiments of the present application, EVA 26031M, EV105 can be used, the weight fraction of the ethylene-vinyl acetate is preferably 40-60 parts, more preferably 45-55 parts, such as 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, preferably a range with any of the above values as the upper or lower limit.

[0040] In the present application, the sodium-based surlyn resin is copolymerized from ethylene (C2H4) and methacrylic acid (CH2=C(CH3)COOH), and after copolymerization, a product with ionic bonds is formed through neutralization reaction with metal sodium ions. The ionic bonds enhance the binding force between molecular chains, significantly improve the wear resistance and mechanical strength of the material, while retaining good flexibility and elasticity; and the carboxyl groups in the molecular structure have high polarity, endowing the material with excellent adhesion. The sodium-based surlyn resin has a hardness of 55-70D, and preferred varieties include Surlyn® 8920. The weight fraction of the sodium-based surlyn resin is preferably 10-20 parts, more preferably 12-18 parts, such as 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, preferably a range with any of the above values as the upper or lower limit.

[0041] In the present application, the maleic anhydride groups in the maleic anhydride grafted EVA have very strong reactivity, and can chemically react with polar or non-polar polymers in a molten state. The maleic anhydride groups in the maleic anhydride grafted EVA form stable chemical bonds with the maleic anhydride groups in the maleic anhydride grafted silicone rubber and the high-vinyl content EPDM in the rubber master batch, as a bridge, enhancing the interfacial bonding force of EVA and other matrices, effectively improving the dispersibility of each polymer and reducing the phase separation phenomenon; and can effectively improve the dispersibility of silica microspheres and avoid agglomeration. A three-dimensional network reinforcing structure is formed in the polymer and filler by the compatibilizer, further improving the overall performance of the composite material. The grafting rate of the maleic anhydride grafted EVA is preferably ≥1%, and the preferred model is C250. The weight fraction of the maleic anhydride grafted EVA is preferably 5-10 parts, more preferably 6-8 parts, such as 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and preferably a range value with any of the above values as the upper or lower limit.

[0042] In the present application, the silica microspheres are a lightweight, porous material, and the density of the silica microspheres is usually between 0.1-0.5 g / cm³, which is much lower than that of ordinary rubber materials; the silica microspheres have a large number of micropores inside, which can effectively reduce the density of the overall material. After the silica microspheres are added as fillers to the rubber matrix, they will replace part of the space occupied by the rubber molecular chains, thereby reducing the density of the overall material. In addition, the silica microspheres can also optimize the microstructure of the material and further improve its lightweight performance. The particle size of the silica microspheres is preferably 30-60 μm, and the specific surface area is preferably 200-500 m 2 / g. The preferred variety is ZCX-III-GY. The weight fraction of the silica microspheres is preferably 6-10 parts, more preferably 7-9 parts, such as 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and preferably a range value with any of the above values as the upper or lower limit.

[0043] In the present application, the wear-resistant agent is preferably an alcohol hydroxyl modified silicone wear-resistant agent, which is composed of a silicon-oxygen chain (Si-O-Si) main chain and an amino side chain. The alcohol hydroxyl group has high polarity and reactivity, and can form a strong binding force of molecular crosslinking with the maleic anhydride groups in the formula, thereby improving the wear resistance and other mechanical properties, and the preferred wear-resistant agent is MY8861. The weight fraction of the wear-resistant agent is preferably 6-8 parts, more preferably 7-8 parts.

[0044] In the application, the lubricant preferably comprises one of stearic acid, zinc stearate and calcium stearate, preferably stearic acid 1801; the weight fraction of the lubricant is preferably 1-2 parts, more preferably 1.5-2 parts, such as 1 part, 1.1 part, 1.2 part, 1.3 part, 1.4 part, 1.5 part, 1.6 part, 1.7 part, 1.8 part, 1.9 part, 2 part, preferably a range value with any of the above values as the upper limit or lower limit.

[0045] In the application, the crosslinking agent is preferably dicumyl peroxide and / or 1,4-bis-tert-butyl peroxyisopropyl benzene, more preferably BIBP; the weight fraction of the crosslinking agent is preferably 0.5-0.5 parts, more preferably 0.4-0.5 parts.

[0046] The application combines maleic anhydride grafted modified silicone rubber and high ethylene content EPDM rubber masterbatch, silica microspheres, ethylene-vinyl acetate, sodium-based sarin resin, silica microspheres, wear-resistant agent, compatibilizer, lubricant, crosslinking agent, etc. in an organic manner, wherein: ① ethylene-vinyl acetate: has excellent processability and weak polarity, which is conducive to the injection operation of the overall formula and improves the adhesion to other materials. ② Sodium-based sarin resin is a copolymer of ethylene (C2H4) and methacrylic acid (CH2=C(CH3)COOH), and is a product formed by neutralization reaction with metal sodium ions after copolymerization to form ionic bonds. The ionic bond enhances the bonding force between molecular chains, significantly improves the wear resistance and mechanical strength of the material, while retaining good flexibility and elasticity; and the carboxyl group in the molecular structure has high polarity, which gives the material excellent adhesion. ③ The wear-resistant agent is an alcohol hydroxyl modified silicone wear-resistant agent, which is composed of a silicon-oxygen chain (Si-O-Si) main chain and an amino side chain. The alcohol hydroxyl group has high polarity and reactivity, and can form a strong bonding force of molecular crosslinking with the maleic anhydride groups in the formula, thereby improving the wear resistance and other mechanical properties. ④ The compatibilizer is maleic anhydride grafted EVA: the maleic anhydride groups in the maleic anhydride grafted EVA have strong reactivity and can chemically react with polar or non-polar polymers in a molten state. The maleic anhydride groups form stable chemical bonds with the maleic anhydride groups in the maleic anhydride grafted modified silicone rubber and high ethylene content EPDM rubber in the rubber masterbatch, acting as a bridge to enhance the interfacial bonding force between EVA and other matrices, effectively improving the dispersibility of various polymers and reducing phase separation; and can effectively improve the dispersibility of silica microspheres and avoid agglomeration. The compatibilizer forms a three-dimensional network reinforcing structure in the polymer and filler, further improving the overall performance of the composite material.

[0047] The application also provides a preparation method of the high wear-resistant non-slip high-adhesion injection rubber described above, comprising the following steps:

[0048] A) Put modified rubber masterbatch, ethylene-vinyl acetate, sodium-based sarin resin and maleic anhydride grafted EVA into a mixing mill, heat and mix, when the temperature rises to 80-85℃, add silica microspheres and wear-resistant agent, continue to heat and mix, when the temperature rises to 90-95℃, add lubricant and crosslinking agent, continue to heat and mix, when the temperature rises to 100-105℃, obtain the mixture;

[0049] B) The mixture is extruded and granulated to obtain a mixed masterbatch;

[0050] C) The mixed masterbatch is injection molded to obtain a high wear-resistant, slip-resistant and high-adhesion injection rubber.

[0051] In the present application, the types and amounts of modified rubber masterbatch, ethylene-vinyl acetate, sodium-based sarin resin and maleic anhydride grafted EVA, silica microspheres, wear-resistant agent, lubricant and crosslinking agent are the same as those described above, and will not be repeated here.

[0052] In the present application, the mixing time after adding modified rubber masterbatch, ethylene-vinyl acetate, sodium-based sarin resin and maleic anhydride grafted EVA is preferably 15-20 min, more preferably 16-18 min, the mixing time after adding silica microspheres and wear-resistant agent is preferably 5-8 min, more preferably 6-7 min, and the mixing time after adding lubricant and crosslinking agent is preferably 5-8 min, more preferably 6-7 min.

[0053] After obtaining the mixture, the present application preferably pours the mixture into a granulator, extrudes and granulates to obtain a mixed masterbatch.

[0054] In the present application, the granulator is preferably a double-screw extrusion granulator, which is provided with four temperature zones, the first temperature zone is 92-97℃, the second temperature zone is 98-102℃, the third temperature zone is 103-106℃, and the fourth temperature zone is 107-113℃, specifically, in some embodiments of the present application, the first temperature zone is 95℃, the second temperature zone is 100℃, the third temperature zone is 105℃, and the fourth temperature zone is 110℃; the screw rotation speed of the double-screw base granulator is preferably 40-50 rpm, and the cutting speed is preferably 15-20 rpm.

[0055] After obtaining the mixed masterbatch, the present application pours the mixed masterbatch into the barrel of an injection molding machine, heats it through a feeding device, and then injects it into a molding mold to obtain a high wear-resistant, slip-resistant and high-adhesion injection rubber.

[0056] In the present application, the material pipe of the injection molding machine is provided with four temperature zones, the first temperature zone is 92-97℃, the second temperature zone is 98-102℃, the third temperature zone is 103-106℃, and the fourth temperature zone is 107-113℃. Specifically, in some embodiments of the present application, the first temperature zone is 95℃, the second temperature zone is 100℃, the third temperature zone is 105℃, and the fourth temperature zone is 110℃. The temperature of the upper mold plate of the molding mold is preferably 175-185℃, more preferably 185℃, the temperature of the lower mold plate of the molding mold is preferably 175-185℃, more preferably 185℃, and the vulcanization time of the injection molding is preferably 220-280s, more preferably 240-260s, such as 220s, 230s, 240s, 250s, 260s, 270s, 280s, preferably the range value with the above-mentioned any value as the upper limit or lower limit.

[0057] The present application also provides a rubber sole prepared from the high wear-resistant and high-adhesion injection rubber described above. The present application prepares a rubber outsole with hardness 65±3A, density 0.8±0.1g / cm 3 , DIN wear resistance ≤30mm 3 , dynamic dry slip ≥0.9, dynamic wet slip ≥0.6, adhesive strength ≥30N / cm, tensile strength ≥20MPa, and right-angle tear strength ≥40N / cm through a one-step injection process, which has excellent wear resistance and slip resistance, solves the technical bottleneck of poor adhesion and insufficient slip resistance of existing lightweight injection rubber outsoles in the industry, and has broad application prospects and market value.

[0058] In order to further illustrate the present application, the high wear-resistant and high-adhesion injection rubber, its preparation method and application provided by the present application are described in detail below in conjunction with examples, but it should not be understood as limiting the scope of protection of the present application.

[0059] Preparation of modified rubber masterbatch

[0060] ① Weighing: first cut the silicone rubber NE-GT141 and EPDM 5565 into small pieces, then weigh NE-GT161, EPDM 5565, EPDM 3745P, grafting agent maleic anhydride, hydroxyl silane coupling agent KH560, initiator benzoyl peroxide BPO, flow aid erucic amide and white carbon black according to the weight fraction in Table 1; wherein:

[0061] Silicone rubber NE-GT141: hardness 40±2A, density 0.98g / cm 3 , tensile strength 6.5MPa, tear strength 16N / mm, elongation at break 380%, permanent compression set 28%, Dongjue Silicone Group Co., Ltd.

[0062] EPDM 5565: ENB content 7.5%, density 0.86 g / cm 3 , Mooney viscosity 65 (ML 1+4 / 125℃), molecular weight 200,000, Dow Chemical Company.

[0063] EPDM 3745P: ENB content 0.5%, density 0.88 g / cm 3 , Mooney viscosity 45 (ML 1+4 / 125℃), molecular weight 150,000, Dow Chemical Company.

[0064] Maleic anhydride: melting point 53℃, Shandong Longhui Chemical Co., Ltd.

[0065] KH560: Dongguan Shanyi Plastic Co., Ltd.

[0066] BPO: melting point 103-106℃, decomposition temperature: 135-170℃, BASF.

[0067] Erucamide: melting point 78-82℃, Liaoning Oak Chemical Co., Ltd.

[0068] White carbon black AEROSIL 200: BET specific surface area about 200 m 2 / g, particle size 7-40 nm, Wacker.

[0069] ②Stir: according to the proportion, sequentially weigh and pour into a high-speed stirrer for mixing for 70±10 min, the stirring speed is 1000±10 rpm, and the mixing temperature is 80±10℃.

[0070] ③Pelletization: the blended mixture after high-speed stirring is subjected to high-temperature melt grafting modification, extrusion and pelletization by a double-screw pelletizer, and the processing temperature is set to 160±10℃.

[0071] ④Drying: the modified rubber masterbatch is vacuum dried at 50±10℃ for 2 hours, and stored for use.

[0072] The obtained modified rubber masterbatch is dried and pressed into a 4mm test piece for testing, and the performance test data are shown in Table 1.

[0073] Table 1 Performance data of modified rubber masterbatch in Examples 1-5

[0074]

[0075] From the performance data of modified rubber masterbatch in Examples 1-5, it can be seen from Table 1 that as the content of silicone rubber NE-GT141 increases from 30 parts to 70 parts and the addition amount of EPDM 5565 decreases from 70 parts to 30 parts, the density of the final rubber test piece gradually increases, the wear resistance gradually improves, but the slip resistance gradually decreases. In order to balance the various properties, it is preferred to perform injection experiments on the modified rubber masterbatch 3 and other elastomer matrices.

[0076] Comparative Example 1 was performed using EPDM with a low ENB content. It was found that as the ENB content decreases, the DIN wear resistance of the final modified rubber masterbatch deteriorates, and the dynamic dry and wet slip tensile strength, tear strength and other properties also decrease. This shows that EPDM with a high ENB content is beneficial to increasing the crosslinking points, and the vulcanized EPDM has a higher crosslinking density, thereby exhibiting better wear resistance and physical and mechanical properties.

[0077] Examples 6-19 and Comparative Examples 2-9

[0078] ① Weighing: According to the amount of the formula in Tables 2-4, weigh BIBP and stearic acid as the first group; weigh silica microspheres and wear-resistant agent as the second group; and weigh the remaining materials as the third group.

[0079] ② Mixing: First, pour the third group of materials into the mixer and turn on the machine. When the temperature rises to between 85°C, pour in the second group of materials. When the temperature rises to 95°C, pour in the first group of materials. When the temperature rises to 105°C, pour out the mixed materials.

[0080] ③ Material preparation: Pour the mixed materials into the material preparation machine, and adjust the first, second, third and fourth zone temperatures to 95, 100, 105 and 110°C respectively. Adjust the screw speed to 45 revolutions per minute and the cutting speed to 20 revolutions per minute.

[0081] ④ Injection: Pour the prepared particles into the hopper of the injection molding machine, and adjust the first, second, third and fourth zone temperatures to 95, 100, 105 and 110°C respectively. Adjust the mold temperature of the upper and lower mold plates to 180±5°C and 180±5°C respectively, and the vulcanization time to 250±30 seconds.

[0082] Among them, EVA 26031M: hardness 82A, density 0.95 g / cm 3 , VA content 26%, tensile strength 12.8 MPa, tear strength 33 N / mm, elongation at break 780%, melt index 3.0 g / 10 min, melting point 70°C, Asia Polymer Co., Ltd.

[0083] Modified rubber masterbatch (Example 3): hardness 50A, density 1.01 g / cm 3Tensile strength 21.2 MPa, tear strength 38 N / mm, elongation at break 580%, self-made.

[0084] Surlyn® 8920: hardness 66D, density 0.95 g / cm 3 , melt index 0.9 g / 10 min, tensile strength 37.2 MPa, elongation at break 350%, tear strength 98 N / mm, melting point 88℃, DuPont.

[0085] C250: grafting rate 1.5%, hardness 84A, density 0.96 g / cm 3 , tensile strength 11.4 MPa, tear strength 73 N / mm, elongation at break 660%, melt index 1.4 g / 10 min, melting point 71℃.

[0086] Silica microspheres ZCX-III-GY: particle size 38-54 um, specific surface area 300-400 m 2 / g, density 0.41 g / cm 3 , Qingdao Bangkai High-tech Material Co., Ltd.

[0087] Wear-resistant agent MY8861: hydroxyl content 0.5±0.1%, viscosity (25℃): 200-800 cst, solid content≥98%, Mingyi Silicon Industry Co., Ltd.

[0088] BIBP: Sinopec.

[0089] Stearic acid 1801: Indonesia Dukuda.

[0090] Table 2 Raw material ratio in examples 6-12

[0091]

[0092] Table 3 Raw material ratio in examples 13-19

[0093]

[0094] Table 4 Raw material ratio in comparative examples 2-9

[0095]

[0096] The mechanical properties of the rubbers in examples 6-19 and comparative examples 2-9 were detected, and the results are shown in Tables 5-7.

[0097] Table 5 Mechanical property test of rubber in examples 6-12

[0098]

[0099] Table 6 Mechanical property test of rubber in Examples 13-19

[0100]

[0101] Table 7 Mechanical property test of rubber in Comparative Examples 2-9

[0102]

[0103] From the test data of Examples 6-11, it can be seen that as the amount of silica microspheres gradually increases, the density / hardness / DIN abrasion resistance / tensile strength / tear strength of the rubber sole gradually decreases, but the dynamic slip resistance and adhesion strength gradually increase. It shows that the large number of micropores inside the silica microspheres can effectively reduce the density of the overall material. Especially in Comparative Example 5, if no silica microspheres are added, the density / hardness increases significantly, which cannot meet the requirements of light weight and comfort.

[0104] From the comparative data of Examples 11, 12 and Example 8, it can be seen that as the amount of abrasion resistant agent increases, the abrasion resistance of the rubber sole improves, but the dynamic slip resistance and adhesion strength gradually decrease. It shows that the abrasion resistant agent itself has lubricity, when it is used as an abrasion resistant agent, a smooth film will be formed on the surface of the material, which will reduce the friction coefficient of the surface, thereby affecting the slip resistance and adhesion performance. Especially in Comparative Example 6 without adding the abrasion resistant agent, although the slip resistance is more excellent, the abrasion resistance decreases significantly.

[0105] From the comparative data of Examples 13, 14 and Example 8, it can be seen that as the amount of compatibilizer C250 gradually decreases, the density / hardness / DIN abrasion resistance / dynamic slip resistance of the rubber sole has a slight decrease, but the tensile strength / tear strength decreases significantly. This is because the maleic anhydride groups in the maleic anhydride grafted EVA have very strong reactivity, which can chemically react with polar or non-polar polymers in the molten state, enhance the interfacial bonding force and improve the dispersibility. In Comparative Example 4 without adding compatibilizer C250, the biggest impact is the decrease of tensile strength / tear strength. It shows that if the formula system lacks compatibilizer C250, the silica microspheres are easy to agglomerate, the compatibility between the polymer matrices decreases, resulting in the decrease of various properties. It shows that the compatibilizer is crucial to avoid the agglomeration of silica microspheres and improve the mechanical properties.

[0106] From the comparative data of examples 15-19 and example 8, it can be seen that as the amount of modified rubber masterbatch gradually increases, the rubber sole adhesion strength is significantly improved, and the density / abrasion resistance / dynamic slip resistance / tensile strength / tear strength gradually increases, which shows that by grafting modification of silicone rubber and EPDM rubber with maleic anhydride (MAH), maleic anhydride is grafted onto the molecular chains of silicone rubber and EPDM through free radical reaction, forming modified silicone rubber and modified EPDM rubber with polar functional groups, which can significantly enhance the adhesion between silicone rubber and EPDM and other materials.

[0107] From the comparative data of comparative examples 2, 8, 9 and example 8, it can be seen that if no modified rubber masterbatch is added, or only unmodified silicone rubber or EPDM rubber is added, the slip resistance / adhesion strength or abrasion resistance / adhesion strength of the rubber sole is significantly reduced, which shows that the silicone rubber in the rubber masterbatch contributes to the slip resistance, and the EPDM rubber contributes to the abrasion resistance, and the silicone rubber / EPDM rubber modified by maleic anhydride can further improve the adhesion performance.

[0108] From the comparative data of comparative example 3 and example 8, it can be seen that if no sodium-based shirin resin is added, the adhesion strength / abrasion resistance / tensile strength / tear strength of the rubber sole decreases, among which the adhesion strength is the most affected. This shows that the sodium-based shirin resin forms an ionic bond with metal sodium ions after copolymerization of ethylene and methacrylic acid, significantly improving the abrasion resistance and mechanical strength of the material, and the high polarity of the carboxyl group improves the adhesion performance.

[0109] From the comparative data of comparative example 7 and example 8, it can be seen that if EVA is used as a single matrix, and no modified rubber masterbatch, sodium-based shirin resin and compatibilizer C250 are added, the slip resistance / adhesion strength / tear strength of the rubber sole is significantly reduced, which shows that the technical solution of the present application for preparing a rubber sole with excellent performance by grafting modification of the rubber masterbatch with maleic anhydride, and then organically combining with ethylene-vinyl acetate, sodium-based shirin resin, maleic anhydride grafted EVA, silica microspheres, abrasion resistant agent, lubricant, crosslinking agent, etc. is feasible.

[0110] The above is only a preferred embodiment of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A highly wear-resistant, non-slip, and highly adhesive injection rubber, comprising the following raw materials in parts by weight: 20-35 parts of modified rubber masterbatch, 40-60 parts of ethylene vinyl acetate, 10-20 parts of sodium surin resin, 5-10 parts of maleic anhydride grafted EVA, 6-10 parts of silica gel microspheres, 6-8 parts of anti-wear agent, 1-2 parts of lubricant, and 0.3-0.5 parts of cross-linking agent; The modified rubber masterbatch is obtained by grafting maleic anhydride onto a mixture of silicone rubber and EPDM rubber; The mass fraction of the non-conjugated diene monomer in the EPDM rubber is 4.5-8%.

2. The high wear-resistant, anti-skid and high-adhesion injection rubber according to claim 1, characterized in that: The modified rubber masterbatch is prepared according to the following steps: In parts by weight, 30-70 parts of silicone rubber, 30-70 parts of EPDM rubber, 4-6 parts of maleic anhydride, 2-3 parts of hydroxy silane coupling agent, 0.4-0.6 parts of initiator, 0.8-1 parts of flow aid and 18-20 parts of white carbon black are mixed, melted, extruded into granules and dried to obtain a modified rubber masterbatch.

3. The high wear-resistant, anti-skid and high-adhesion injection rubber according to claim 2, characterized in that: The mixing temperature is 70-90°C and the mixing time is 60-80 minutes; The temperature of the extrusion granulation is 150-70°C.

4. The high wear-resistant, anti-skid and high-adhesion injection rubber according to claim 1, characterized in that: The silica microspheres have a density of 0.1-0.5 g / cm³, a particle size of 30-60 μm, and a specific surface area of ​​200-500 m 2 / g.

5. The method for preparing the highly wear-resistant, anti-slip and high-adhesive injection rubber according to claim 1, comprising the following steps: A) Add modified rubber masterbatch, ethylene vinyl acetate, sodium surin resin and maleic anhydride grafted EVA into an internal mixer and heat and mix. When the temperature reaches 80-85°C, add silica gel microspheres and anti-wear agent, continue heating and mixing. When the temperature reaches 90-95°C, add lubricant and cross-linking agent, continue heating and mixing, and when the temperature reaches 100-105°C, obtain a mixed material. B) extruding and granulating the mixture to obtain a mixed masterbatch; C) injection molding the mixed masterbatch to obtain a highly wear-resistant, non-slip, and highly adhesive injection rubber.

6. The preparation method according to claim 5, characterized in that In step A), the mixing time after adding the modified rubber masterbatch, ethylene vinyl acetate, sodium surin resin and maleic anhydride grafted EVA is 15 to 20 minutes, the mixing time after adding the silica gel microspheres and the wear-resistant agent is 5 to 8 minutes, and the mixing time after adding the lubricant and the cross-linking agent is 5 to 8 minutes.

7. The preparation method according to claim 5, characterized in that In step B), the extrusion granulation is provided with four temperature zones, the first temperature zone is 92-97°C, the second temperature zone is 98-102°C, the third temperature zone is 103-106°C, and the fourth temperature zone is 107-113°C.

8. The preparation method according to claim 5, characterized in that In the step C), the injection molding feed is provided with four temperature zones, the first temperature zone is 92-97°C, the second temperature zone is 98-102°C, the third temperature zone is 103-106°C, and the fourth temperature zone is 107-113°C.

9. The preparation method according to claim 5, characterized in that In the step C), the injection molding temperature is 175-185° C., and the injection molding vulcanization time is 220-280 seconds.

10. A rubber sole, characterized in that: The invention is prepared from the high wear-resistant, anti-skid and high adhesive strength injection rubber according to any one of claims 1 to 4.

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