High wear resistance, slip resistance and high adhesive force injection rubber, preparation method and application thereof

Abstract

The application provides a high-wear-resistance, high-adhesion, high-slip-resistance and high-bonding-force injection rubber, a preparation method and application thereof, and comprises the following raw materials in parts by weight: 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 gel microspheres 6-10 parts, wear-resistant agent 6-8 parts, lubricant 1-2 parts, crosslinking agent 0.3-0.5 parts; the modified rubber master batch is obtained by grafting modification of a mixture of maleic anhydride, 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 rubber outsole of the 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 outsole in the industry, and has 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 step A), the mixing time after adding modified rubber masterbatch, ethylene-vinyl acetate, sodium sarin resin and maleic anhydride grafted EVA is 15-20 min, the mixing time after adding silica microspheres and wear-resistant agent is 5-8 min, and the mixing time after adding lubricant and crosslinking agent is 5-8 min.

[0019] Preferably, the extrusion granulation in step B) has 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 step C), the injection molding feeder has four temperature zones: the first temperature zone has a temperature of 92~97℃, the second temperature zone has a temperature of 98~102℃, the third temperature zone has a temperature of 103~106℃, and the fourth temperature zone has a temperature of 107~113℃.

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

[0022] This invention provides a rubber shoe sole, which is prepared from the high wear-resistant, non-slip, and high-adhesion injection rubber described above.

[0023] This invention provides a high-wear-resistant, anti-slip, and high-adhesion injection-molded rubber, comprising the following raw materials in parts by weight: 20-35 parts modified rubber masterbatch, 40-60 parts ethylene-vinyl acetate, 10-20 parts sodium-based sarin resin, 5-10 parts maleic anhydride-grafted EVA, 6-10 parts silica microspheres, 6-8 parts wear-resistant agent, 1-2 parts lubricant, and 0.3-0.5 parts crosslinking agent; the modified rubber masterbatch is obtained by grafting maleic anhydride onto a mixture of silicone rubber and ethylene propylene diene monomer (EPDM); the content of non-conjugated diene monomers in the EPDM is 4.5-8%. Rubber masterbatch was prepared by grafting maleic anhydride onto modified silicone rubber and high-vinyl-content EPDM rubber. This masterbatch was then organically combined with ethylene-vinyl acetate, sodium sarin resin, maleic anhydride-grafted EVA, silica microspheres, wear-resistant agents, lubricants, and crosslinking agents. The resulting material, with a hardness of 65±3A and a density of 0.8±0.1 g / cm³, was produced via injection molding. 3 DIN abrasion resistance ≤30mm 3 The rubber outsole of this invention possesses excellent wear resistance and anti-slip properties, overcoming the technical bottlenecks of poor adhesion and insufficient anti-slip properties in existing lightweight injection-molded rubber outsoles, and has significant market potential. It exhibits dynamic dry slip resistance ≥0.9, dynamic wet slip resistance ≥0.6, adhesive strength ≥30 N / cm, tensile strength ≥20 MPa, and right-angle tear strength ≥40 N / cm. Detailed Implementation

[0024] This invention provides a high-wear-resistant, anti-slip, and high-adhesion injection rubber, comprising the following raw materials in parts by weight:

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

[0026] The modified rubber masterbatch is obtained by grafting maleic anhydride onto a mixture of silicone rubber and EPDM rubber.

[0027] The mass fraction of non-conjugated diene monomers in the EPDM rubber is 4.5-8%.

[0028] In this invention, the modified rubber masterbatch is preferably 20 to 35 parts by weight, more preferably 25 to 30 parts, such as 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35 parts, and preferably a range of values ​​with any of the above values ​​as the upper or lower limit.

[0029] This invention utilizes a mixed rubber masterbatch of maleic anhydride-grafted modified silicone rubber and high-vinyl-content EPDM rubber. Silicone rubber, due to the presence of flexible silicon-oxygen bonds (Si-O-Si) in its molecular structure, exhibits excellent rubber texture and superior anti-slip properties. However, its wear resistance is relatively weak under repeated friction conditions. EPDM rubber, on the other hand, is an elastomer polymerized from ethylene, propylene, and non-conjugated diene monomers (ENB). The higher the content of the third monomer ENB, the more cross-linking points exist in the molecular chain, resulting in a higher cross-linking density in the vulcanized EPDM, thus exhibiting better wear resistance and physical and mechanical properties. However, EPDM is a non-polar polymer with low surface energy, leading to a lower coefficient of friction with the ground or other materials. On wet and slippery surfaces, EPDM rubber exhibits poor anti-slip properties and is prone to slippage. Both silicone rubber and EPDM rubber are non-polar materials with low surface energy, resulting in poor adhesion to other substances. To improve the adhesion properties of both silicone rubber and EPDM rubber, maleic anhydride (MAH) was grafted onto the molecular chains of silicone rubber and EPDM rubber via a free radical reaction, forming modified silicone rubber and modified EPDM rubber with polar functional groups. These polar functional groups can significantly enhance the adhesion between silicone rubber and EPDM rubber and other materials. The silicone rubber includes silicone rubber with a hardness of 40±5A, preferably NE-GT141; the EPDM rubber includes grades with an ENB mass fraction of 4.5%~8%, preferably EPDM 5565.

[0030] In this invention, the modified rubber masterbatch is obtained by grafting maleic anhydride onto a mixture of silicone rubber and EPDM rubber, specifically including the following steps:

[0031] By weight, 30-70 parts of silicone rubber, 30-70 parts of EPDM rubber, 4-6 parts of maleic anhydride, 2-3 parts of hydroxysilane coupling agent, 0.4-0.6 parts of initiator, 0.8-1 parts of flow aid and 18-20 parts of silica are mixed and then melted, extruded and granulated and dried to obtain modified rubber masterbatch.

[0032] In this invention, the hardness of the silicone rubber is preferably 40±5A, and the weight parts of the silicone rubber are preferably 30 to 70 parts, more preferably 40 to 60 parts, such as 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, preferably within the range of any of the above values ​​as the upper or lower limit.

[0033] In this invention, the mass fraction of ENB in ​​the EPDM rubber is preferably 4.5-8%, more preferably 5-8%, and most preferably 6-7.5%. The number average molecular weight of the EPDM rubber is preferably 180,000-220,000. The weight parts of the EPDM rubber are preferably 30-70 parts, more preferably 40-60 parts, such as 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, and 70 parts. Preferably, the values ​​are within the range of the above values ​​as the upper or lower limit.

[0034] In this invention, the maleic anhydride is preferably 4-6 parts by weight, more preferably 4-5 parts. The hydroxysilane coupling agent is preferably KH560, and the weight of the hydroxysilane coupling agent is preferably 2-3 parts, more preferably 2.5-3 parts; the initiator is preferably benzoyl peroxide (BPO), and the weight of the initiator is preferably 0.4-0.6 parts, more preferably 0.5-0.6 parts; the flow aid is preferably erucamide, and the weight of the flow aid is preferably 0.8-1 parts, more preferably 0.9-1 parts; the weight of the silica is preferably 18-20 parts, more preferably 18-19 parts.

[0035] In this invention, silicone rubber, ethylene propylene diene monomer (EPDM) rubber, grafting agent maleic anhydride, hydroxysilane coupling agent, initiator benzoyl peroxide (BPO), flow aid erucamide, and silica are weighed according to the above-mentioned weight proportions and poured into a high-speed mixer for mixing to obtain a mixture.

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

[0037] The present invention modifies the mixture obtained after mixing by high-temperature melt grafting through a twin-screw granulator, followed by extrusion granulation and drying to obtain modified rubber masterbatch.

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

[0039] In this invention, the mass fraction of vinyl acetate in the ethylene-vinyl acetate mixture is preferably 18-28%. Specifically, in some embodiments of this invention, EVA 26031M or EV105 can be used. The weight fraction of the ethylene-vinyl acetate mixture 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, and 60 parts. Preferably, the range of values ​​above is the upper or lower limit.

[0040] In this invention, the sodium-based sarin resin is a product formed by copolymerizing ethylene (C2H4) and methacrylic acid (CH2=C(CH3)COOH) and then neutralizing them with sodium ions to form ionic bonds. These ionic bonds enhance the bonding force between molecular chains, significantly improving the material's wear resistance and mechanical strength while retaining good flexibility and elasticity. Furthermore, the high polarity of the carboxyl groups in the molecular structure endows the material with excellent adhesion properties. Grades with a hardness of 55-70D are available, with Surlyn® 8920 being a preferred example. The sodium-based sarin resin is preferably 10-20 parts by weight, more preferably 12-18 parts, such as 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts, and preferably falls within the range of any of the above values ​​as the upper or lower limit.

[0041] In this invention, the maleic anhydride groups in the maleic anhydride-grafted EVA possess extremely strong reactivity, enabling them to chemically react with polar or non-polar polymers in the molten state. These maleic anhydride groups form stable chemical bonds with the maleic anhydride-grafted modified silicone rubber and high-vinyl-content EPDM rubber in the rubber masterbatch, acting as a bridge to enhance the interfacial bonding between EVA and other matrices, effectively improving the dispersibility of each polymer and reducing phase separation. Furthermore, they effectively improve the dispersibility of silica microspheres, preventing agglomeration. A three-dimensional network reinforcement structure is formed in the polymer and filler through a compatibilizer, further enhancing the overall performance of the composite material. Grades with a grafting rate ≥1% are included, with C250 being a preferred model. The weight percentage 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, or 10 parts, preferably within the range of any of the above values ​​as the upper or lower limit.

[0042] In this invention, the silica microspheres are a lightweight, porous material with a density typically between 0.1 and 0.5 g / cm³, far lower than that of ordinary rubber materials. The silica microspheres contain numerous micropores, which effectively reduce the overall material density. When added to a rubber matrix as a filler, the silica microspheres replace some of the space occupied by rubber molecular chains, thereby reducing the overall material density. Furthermore, the silica microspheres can optimize the material's microstructure, further enhancing its lightweight properties. The preferred particle size of the silica microspheres is 30–60 μm, and the preferred specific surface area is 200–500 m². 2 The grade is / g, with ZCX-Ⅲ-GY being a preferred variety. The weight parts of the silica microspheres are preferably 6 to 10 parts, more preferably 7 to 9 parts, such as 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and preferably any of the above values ​​as the upper or lower limit.

[0043] In this invention, the wear-resistant agent is preferably a silicone wear-resistant agent modified with alcohol hydroxyl groups, which consists of a silicon oxide chain (Si-O-Si) main chain and an amino side chain. The alcohol hydroxyl groups have high polarity and reactivity, and can form a strong molecular cross-linking bond with the maleic anhydride groups in the formulation, thereby improving other mechanical properties while improving wear resistance. The preferred wear-resistant agent is MY8861. The weight percentage of the wear-resistant agent is preferably 6 to 8 parts, more preferably 7 to 8 parts.

[0044] In this invention, the lubricant preferably includes one of stearic acid, zinc stearate, and calcium stearate, preferably stearic acid 1801; the weight of the lubricant is preferably 1 to 2 parts, more preferably 1.5 to 2 parts, such as 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, preferably within the range of any of the above values ​​as the upper or lower limit.

[0045] In this invention, the crosslinking agent is preferably dicumyl peroxide and / or 1,4-bis-tert-butylperoxide, more preferably BIBP; the weight fraction of the crosslinking agent is preferably 0.5 to 0.5 parts, more preferably 0.4 to 0.5 parts.

[0046] This invention organically combines maleic anhydride-grafted modified silicone rubber and high-vinyl-content EPDM rubber masterbatch, silica microspheres, ethylene-vinyl acetate, sodium-based sarin resin, silica microspheres, wear-resistant agents, compatibilizers, lubricants, crosslinking agents, etc. Specifically: ① Ethylene-vinyl acetate: possesses excellent processability and weak polarity, which is beneficial for the overall formulation injection operation and improves adhesion to other materials. ② Sodium-based sarin resin is a product formed by copolymerizing ethylene (C2H4) and methacrylic acid (CH2=C(CH3)COOH), which, after copolymerization, undergoes a neutralization reaction with metallic sodium ions to form ionic bonds. These ionic bonds enhance the bonding force between molecular chains, significantly improving the material's wear resistance and mechanical strength, while retaining good flexibility and elasticity; moreover, the high polarity of the carboxyl groups in the molecular structure endows the material with excellent adhesion properties. ③ The wear-resistant agent selected is a silicone wear-resistant agent modified with alcohol hydroxyl groups. It consists of a silicon-oxygen chain (Si-O-Si) main chain and amino side chains. The alcohol hydroxyl groups have high polarity and reactivity, enabling them to form a strong molecular cross-linking bond with the maleic anhydride groups in the formulation. This improves wear resistance while also enhancing other mechanical properties. ④ The compatibilizer selected is maleic anhydride-grafted EVA. The maleic anhydride groups in maleic anhydride-grafted EVA have extremely strong reactivity, capable of chemically reacting with polar or non-polar polymers in the molten state. These maleic anhydride groups form stable chemical bonds with the maleic anhydride-grafted modified silicone rubber and the maleic anhydride groups in high-vinyl-content EPDM rubber in the rubber masterbatch. This acts as a bridge, enhancing the interfacial bonding between EVA and other matrices, effectively improving the dispersibility of each polymer, reducing phase separation, and effectively improving the dispersibility of silica microspheres, preventing agglomeration. The compatibilizer forms a three-dimensional network reinforcement structure in the polymers and fillers, further improving the overall performance of the composite material.

[0047] This invention also provides a method for preparing the high wear-resistant, anti-slip, and high-adhesion injection rubber described above, comprising the following steps:

[0048] A) Modified rubber masterbatch, ethylene-vinyl acetate, sodium sarin resin and maleic anhydride grafted EVA are added to a mixer and heated for mixing. When the temperature reaches 80~85℃, silica gel microspheres and wear-resistant agent are added and the mixture is heated and mixed. When the temperature reaches 90~95℃, lubricant and crosslinking agent are added and the mixture is heated and mixed. When the temperature reaches 100~105℃, a mixture is obtained.

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

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

[0051] In this invention, the types and amounts of the modified rubber masterbatch, ethylene-vinyl acetate, sodium 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 this invention, the mixing time after adding modified rubber masterbatch, ethylene-vinyl acetate, sodium 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 invention preferably pours the mixture into a granulator and extrudes and granulates it to obtain mixed masterbatch.

[0054] In this invention, the granulator is preferably a twin-screw extruder granulator, which has four temperature zones: a first temperature zone of 92-97°C, a second temperature zone of 98-102°C, a third temperature zone of 103-106°C, and a fourth temperature zone of 107-113°C. Specifically, in some embodiments of this invention, the first temperature zone is 95°C, the second temperature zone is 100°C, the third temperature zone is 105°C, and the fourth temperature zone is 110°C. The screw speed of the twin-screw granulator is preferably 40-50 rpm, and the cutting speed is preferably 15-20 rpm.

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

[0056] In this invention, the injection molding machine's feed tube is equipped with four temperature zones: the first zone has a temperature of 92-97°C, the second zone has a temperature of 98-102°C, the third zone has a temperature of 103-106°C, and the fourth zone has a temperature of 107-113°C. Specifically, in some embodiments of this invention, the first zone temperature is 95°C, the second zone temperature is 100°C, the third zone temperature is 105°C, and the fourth zone temperature is 110°C. The temperature of the upper mold plate is preferably 175-185°C, more preferably 185°C, and the temperature of the lower mold plate is preferably 175-185°C, more preferably 185°C. The vulcanization time for injection molding is preferably 220-280 seconds, more preferably 240-260 seconds, such as 220 seconds, 230 seconds, 240 seconds, 250 seconds, 260 seconds, 270 seconds, 280 seconds. s is preferably a range of values ​​with any of the above values ​​as the upper or lower limit.

[0057] This invention also provides a rubber shoe sole, prepared from the high-wear-resistant, non-slip, and high-adhesion injection-molded rubber described above. This invention produces a sole with a hardness of 65±3A and a density of 0.8±0.1 g / cm³ using a single injection molding process. 3 DIN abrasion resistance ≤30mm 3 The rubber outsole, with dynamic dry slip resistance ≥0.9, dynamic wet slip resistance ≥0.6, adhesive strength ≥30N / cm, tensile strength ≥20MPa, and right-angle tear strength ≥40N / cm, has excellent wear resistance and anti-slip performance. It solves the technical bottleneck of poor adhesion and insufficient anti-slip properties of existing lightweight injection-molded rubber outsoles in the industry, and shows broad application prospects and market value.

[0058] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, describes a high wear-resistant, anti-slip, and high-adhesion injection rubber provided by the present invention, its preparation method, and its application, but this should not be construed as limiting the scope of protection of the present invention.

[0059] Preparation of modified rubber masterbatch in Examples 1-5 and Comparative Example 1

[0060] ① Weighing: First, cut silicone rubber NE-GT141 and EPDM 5565 into small pieces. Then, weigh NE-GT161, EPDM 5565, EPDM 3745P, grafting agent maleic anhydride, hydroxysilane coupling agent KH560, initiator benzoyl peroxide BPO, flow aid erucamide, and silica according to the weight proportions in Table 1; where:

[0061] Silicone rubber NE-GT141: Hardness 40±2A, density 0.98g / cm³ 3 Tensile strength 6.5MPa, tear strength 16N / mm, elongation at break 380%, permanent compression set 28%, Dongjue Organosilicon Group Co., Ltd.

[0062] EPDM 5565: ENB content 7.5%, density 0.86 g / cm³ 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 / cm³ 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 Plastics Co., Ltd.

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

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

[0068] AEROSIL 200 silica: BET specific surface area approximately 200 m² 2 / g, particle size 7~40nm, Evonik Degussa.

[0069] ② Mixing: Weigh the ingredients according to the proportions and pour them into a high-speed mixer and mix for 70±10 minutes at a speed of 1000±10 rpm and a temperature of 80±10℃.

[0070] ③ Granulation: The blend after high-speed mixing is subjected to high-temperature melt grafting modification, extrusion and granulation through a twin-screw granulator, with the processing temperature set at 160±10℃.

[0071] ④ Drying: The modified rubber masterbatch is vacuum dried at 50±10℃ for 2 hours and then sealed for later use.

[0072] The modified rubber masterbatch was dried and pressed into 4mm test pieces for testing. The performance test data are shown in Table 1.

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

[0074]

[0075] As can be seen from Table 1, the performance data of the modified rubber masterbatch in Examples 1 to 5 show that as the content of silicone rubber NE-GT141 increases from 30 parts to 70 parts and the amount of EPDM 5565 added decreases from 70 parts to 30 parts, the density of the final rubber sample gradually increases and the wear resistance gradually improves, but the anti-slip performance gradually decreases. In order to balance the various properties, the modified rubber masterbatch 3 is preferred to be used in injection molding experiments with other elastomer matrices.

[0076] A comparative test was conducted using EPDM with low ENB content (Comparative Example 1). It was found that as the ENB content decreased, the final modified rubber masterbatch exhibited worse DIN abrasion resistance, and its dynamic dry and wet tensile strength, tear strength, and other properties also declined. This indicates that EPDM with high ENB content is beneficial for increasing crosslinking points, resulting in vulcanized EPDM with a higher crosslinking density, thus exhibiting better abrasion resistance and physical and mechanical properties.

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

[0078] ① Weighing: Based on the dosage 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; weigh the remaining materials as the third group.

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

[0080] ③ Material preparation: Pour the mixed material into the material preparation machine. Adjust the temperatures of the first, second, third, and fourth zones to 95, 100, 105, and 110℃ respectively. Adjust the screw speed to 45 rpm and the cutting speed to 20 rpm.

[0081] ④ Injection: Pour the prepared particles into the material barrel of the injection molding machine. The temperatures of the first, second, third, and fourth feeding zones are adjusted to 95, 100, 105, and 110 degrees respectively. The temperatures of the upper and lower mold plates are adjusted to 180±5℃ and 180±5℃ respectively. The vulcanization time is 250±30 seconds.

[0082] Among them, EVA 26031M has a hardness of 82A and a density of 0.95 g / cm³. 3 The product contains 26% VA, has a tensile strength of 12.8 MPa, a tear strength of 33 N / mm, an elongation at break of 780%, a melt index of 3.0 g / 10 min, and a melting point of 70℃. It is manufactured by Asia Polymer Co., Ltd.

[0083] Modified rubber masterbatch (Example 3): Hardness 50A, density 1.01 g / cm³ 3Tensile strength 21.2MPa, tear strength 38N / mm, elongation at break 580%, self-made.

[0084] Surlyn® 8920: Hardness 66D, Density 0.95g / cm³ 3 Melt flow index 0.9 g / 10 min, tensile strength 37.2 MPa, elongation at break 350%, tear strength 98 N / mm, melting point 88 °C, DuPont.

[0085] C250: Grafting rate 1.5%, hardness 84A, density 0.96 g / cm³ 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 38-54µm, specific surface area 300-400m² 2 / g, density 0.41g / cm³ 3 Qingdao Bangkai High-Tech Materials 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: Dukuda, Indonesia.

[0090] Table 2 Raw material ratios in Examples 6-12

[0091]

[0092] Table 3 Raw material ratios in Examples 13-19

[0093]

[0094] Table 4 Raw material ratios in Comparative Examples 2-9

[0095]

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

[0097] Table 5 Mechanical property tests of rubber in Examples 6-12

[0098]

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

[0100]

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

[0102]

[0103] The test data from Examples 6-11 show that as the amount of silicone microspheres gradually increases, the density, hardness, DIN abrasion resistance, tensile strength, and tear strength of the rubber sole gradually decrease, while the dynamic anti-slip performance and adhesive strength gradually increase. This indicates that the numerous micropores inside the silicone microspheres can effectively reduce the overall material density. In particular, in Comparative Example 5, without the addition of silicone microspheres, the density and hardness increase significantly, failing to meet the requirements for lightweight and comfort.

[0104] Comparing the data from Examples 11 and 12 with Example 8, it can be seen that as the amount of abrasion-resistant agent added increases, the abrasion resistance of the rubber sole improves, but the dynamic anti-slip performance and adhesive strength gradually decrease. This indicates that the abrasion-resistant agent itself has lubricating properties. When used as an abrasion-resistant agent, it forms a smooth film on the material surface. This film reduces the surface friction coefficient, thus affecting the anti-slip performance and adhesive performance. In particular, in Comparative Example 6 without the addition of abrasion-resistant agent, although the anti-slip performance is better, the abrasion resistance is significantly reduced.

[0105] Comparing the data from Examples 13 and 14 with Example 8, as the amount of compatibilizer C250 gradually decreased, the density, hardness, DIN abrasion resistance, and dynamic slip resistance of the rubber sole slightly decreased, but the tensile strength and tear strength decreased significantly. This is because the maleic anhydride groups in maleic anhydride-grafted EVA have extremely strong reactivity, enabling them to chemically react with polar or non-polar polymers in the molten state, enhancing interfacial bonding and improving dispersibility. In Comparative Example 4, where compatibilizer C250 was not added, the most significant impact was on the decrease in tensile strength and tear strength. This indicates that if compatibilizer C250 is lacking in the formulation system, silica microspheres are prone to agglomeration, reducing the compatibility between the polymer matrices and leading to a decline in various properties. This demonstrates that compatibilizers are crucial for preventing silica microsphere agglomeration and improving mechanical properties.

[0106] Comparing the data from Examples 15-19 with that from Example 8, it can be seen that as the amount of modified rubber masterbatch added gradually increases, the adhesive strength of the rubber sole is significantly improved, and the density, abrasion resistance, dynamic slip resistance, tensile strength, and tear strength gradually increase. This indicates that by grafting maleic anhydride (MAH) onto silicone rubber and EPDM rubber, maleic anhydride is grafted onto the molecular chains of silicone rubber and EPDM rubber through free radical reaction, forming modified silicone rubber and modified EPDM rubber with polar functional groups. These polar functional groups can significantly enhance the adhesion between silicone rubber and EPDM rubber and other materials.

[0107] Comparative data from Examples 2, 8, and 9 with Example 8 show that if no modified rubber masterbatch is added, or only unmodified silicone rubber or EPDM rubber is added, the anti-slip performance / adhesive strength or abrasion resistance / adhesive strength of the rubber sole decreases significantly. This indicates that silicone rubber in the rubber masterbatch contributes to the anti-slip performance, EPDM rubber contributes to the abrasion resistance, and the adhesive performance of silicone rubber / EPDM rubber can be further improved after modification with maleic anhydride.

[0108] The comparative data from Comparative Example 3 and Example 8 show that without the addition of sodium-based sarin resin, the adhesive strength, abrasion resistance, tensile strength, and tear strength of the rubber sole decrease, with the adhesive strength being the most affected. This indicates that the sodium-based sarin resin, through copolymerization of ethylene and methacrylic acid, forms ionic bonds with metallic sodium ions, significantly improving the abrasion resistance and mechanical strength of the material. Simultaneously, the high polarity of the carboxyl groups enhances the adhesive properties.

[0109] The comparative data from Comparative Example 7 and Example 8 show that if EVA is used as a single matrix without the addition of modified rubber masterbatch, sodium sarin resin and compatibilizer C250, the anti-slip performance, adhesive strength and tear strength of the rubber sole decrease significantly. This indicates that the technical solution of this invention, which uses maleic anhydride-modified rubber masterbatch and then organically combines it with ethylene-vinyl acetate, sodium sarin resin, maleic anhydride-grafted EVA, silica microspheres, abrasion resistant agents, lubricants, crosslinking agents and other agents to prepare rubber soles with excellent performance, is feasible.

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-wear-resistant, anti-slip, and high-adhesion injection-molded rubber, comprising the following raw materials in parts by weight: 20-35 parts modified rubber masterbatch, 40-60 parts ethylene-vinyl acetate, 10-20 parts sodium saline resin, 5-10 parts maleic anhydride grafted EVA, 6-10 parts silica microspheres, 6-8 parts wear-resistant agent, 1-2 parts lubricant, and 0.3-0.5 parts crosslinking agent; The modified rubber masterbatch is obtained by grafting maleic anhydride onto a mixture of silicone rubber and EPDM rubber. The mass fraction of non-conjugated diene monomers in the EPDM rubber is 4.5-8%; The modified rubber masterbatch is prepared according to the following steps: By weight, 30-70 parts of silicone rubber, 30-70 parts of EPDM rubber, 4-6 parts of maleic anhydride, 2-3 parts of hydroxysilane coupling agent, 0.4-0.6 parts of initiator, 0.8-1 parts of flow aid and 18-20 parts of silica are mixed and then melted, extruded and granulated and dried to obtain modified rubber masterbatch.

2. The high wear-resistant, anti-slip, and high-adhesion injection-molded rubber according to claim 1, characterized in that, The mixing temperature is 70~90℃, and the mixing time is 60~80min; The extrusion granulation temperature is 70~150℃.

3. The high wear-resistant, anti-slip, and high-adhesion injection-molded 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 m². 2 / g.

4. The preparation method of the high wear-resistant, anti-slip, and high-adhesion injection rubber as described in claim 1, comprising the following steps: A) Modified rubber masterbatch, ethylene-vinyl acetate, sodium sarin resin and maleic anhydride grafted EVA are added to a mixer and heated for mixing. When the temperature reaches 80~85℃, silica gel microspheres and wear-resistant agent are added and the mixture is heated and mixed. When the temperature reaches 90~95℃, lubricant and crosslinking agent are added and the mixture is heated and mixed. When the temperature reaches 100~105℃, a mixture is obtained. B) The mixture is extruded and granulated to obtain a mixed masterbatch; C) The mixed masterbatch is injection molded to obtain high wear-resistant, non-slip, and high-adhesion injection rubber.

5. The preparation method according to claim 4, characterized in that, In step A), the mixing time after adding modified rubber masterbatch, ethylene-vinyl acetate, sodium sarin resin and maleic anhydride grafted EVA is 15-20 min; the mixing time after adding silica microspheres and wear-resistant agent is 5-8 min; and the mixing time after adding lubricant and crosslinking agent is 5-8 min.

6. The preparation method according to claim 4, characterized in that, In step B), the extrusion granulation process has 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℃.

7. The preparation method according to claim 4, characterized in that, In step C), the injection molding feeder has 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℃.

8. The preparation method according to claim 4, characterized in that, In step C), the injection molding temperature is 175~185℃, and the vulcanization time of the injection molding is 220~280s.

9. A rubber shoe sole, characterized in that, It is prepared from the high wear-resistant, non-slip, and high-adhesion injection-molded rubber as described in any one of claims 1 to 3.

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