Wear-resistant high-elastic rubber composite sole and preparation method thereof

Abstract

The invention discloses a wear-resistant high-elasticity rubber composite sole and a preparation method thereof, belongs to the technical field of rubber product processing, and aims to solve the technical problem that the wear resistance and elasticity of a rubber composite sole in the prior art need to be further improved. The material comprises the following raw materials in parts by mass: 80-100 parts of ethylene propylene diene monomer, 3-5 parts of modified polyethylene fiber, 5-6 parts of a modified foaming agent, 12-15 parts of a modified elastomer and 10-12 parts of an auxiliary additive, and is prepared by taking ethylene propylene diene monomer as a base material, the modified polyethylene fiber, the modified elastomer and the modified foaming agent as reinforcing agents and the auxiliary additive as a processing aid. The wear resistance and the elasticity of the rubber composite shoe sole are improved, and the mechanical performance of the rubber composite shoe sole is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber product processing, and particularly relates to a wear-resistant and highly elastic rubber composite sole and a preparation method thereof. Background Art

[0002] Rubber composite soles are innovative products developed by the shoe-making industry to meet the modern consumers' demands for comfort, durability, and functionality. Although traditional single rubber soles have good shock absorption and anti-slip properties, they have limitations in terms of elasticity and wear resistance. With the development of sports science and material technology, sole materials are gradually developing towards compounding and functionality, and rubber composite soles have emerged as the times require.

[0003] In the prior art, rubber composite soles are often prepared by adding other inorganic or organic materials to a rubber matrix to obtain rubber composite soles with good wear resistance and elasticity. However, when adding organic substances such as fibers and elastomers, due to the large difference in compatibility with the rubber matrix, the mechanical properties of the prepared rubber composite soles are poor. Moreover, during the preparation process, the foaming agent used causes uneven distribution of bubbles, resulting in local density differences in the sole, affecting the mechanical strength and wear resistance of the overall structure. At the same time, the incomplete foaming structure weakens the bonding force between the molecular chains of the material, accelerating the wear of the sole. Summary of the Invention

[0004] The purpose of the present invention is to provide a wear-resistant and highly elastic rubber composite sole and a preparation method thereof, aiming to solve the technical problem that the wear resistance and elasticity of rubber composite soles in the prior art need to be further improved.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A wear-resistant and highly elastic rubber composite sole, comprising the following raw materials in parts by mass: 80 - 100 parts of ethylene propylene diene monomer rubber, 3 - 5 parts of modified polyethylene fiber, 12 - 15 parts of modified elastomer, 5 - 6 parts of modified foaming agent, and 10 - 12 parts of auxiliary additive;

[0006] The auxiliary additive is composed of a plasticizer, an antioxidant, an anti-scorching agent, a vulcanizing agent, and an accelerator in a mass ratio of 5:2:1:10:2.

[0007] Further, the plasticizer is dioctyl phthalate, the antioxidant is one or both of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine or 2,6-di-tert-butyl-p-cresol, the anti-scorching agent and the vulcanizing agent are one or both of N-nitrosodiphenylamine or phthalic anhydride, the accelerator is one or both of dibenzothiazole disulfide or N-cyclohexyl-2-benzothiazole sulfenamide, and the vulcanizing agent is sulfur.

[0008] Further, the modified polyethylene fiber is prepared by the following steps:

[0009] A1. Place the polyethylene fiber in a vacuum plasma chamber for plasma treatment to obtain pretreated polyethylene fiber;

[0010] Reaction principle for the preparation of pretreated polyethylene fiber:

[0011] During the reaction, high-energy electrons bombard to break the C-H and C-C bonds in the polyethylene molecular chain, generating free radical active sites, which then react with oxygen in the plasma to form polar groups such as -COOH and -OH. At the same time, ion bombardment forms grooves and pits on the fiber surface to obtain pretreated polyethylene fiber.

[0012] A2. Place dopamine, Tris buffer solution, deionized water and polyethyleneimine in a reaction kettle, stir for 1 - 5 min, add the pretreated polyethylene fiber for impregnation, heat up to 20 - 30 °C, keep warm and react for 18 - 20 h, and perform post-treatment to obtain modified polyethylene fiber.

[0013] Reaction principle for the preparation of modified polyethylene fiber is as follows:

[0014] During the reaction, the Tris buffer solution provides a weakly alkaline condition for dopamine. The catechol group of dopamine is oxidized to dopamine quinone, triggering a self-polymerization reaction to form a layer of dopamine film on the pretreated polyethylene fiber by self-polymerization. The cationic polymer polyethyleneimine is adsorbed on the surface of the negatively charged polydopamine film through electrostatic interaction. At the same time, the amino group of polyethyleneimine forms hydrogen bonds with the hydroxyl group and quinone group of polydopamine to achieve co-deposition and obtain modified polyethylene fiber.

[0015] Further, in step A1, the vacuum pressure of the plasma treatment is 30 - 40 Pa, the power is 100 - 120 W, the gas introduced is oxygen, and the treatment time is 20 - 30 s; in step A2, the dosage ratio of dopamine, Tris buffer solution, deionized water and polyethyleneimine is 5 - 8 g: 3 - 5 mL: 1000 - 1500 mL: 5 - 8 g, the impregnation ratio is 1: 30 - 35, and the post-treatment steps include: after the reaction is completed, perform suction filtration, wash the filter cake with deionized water and ethanol for 1 - 2 times, transfer it to a drying oven at a temperature of 50 - 70 °C, dry to room temperature to obtain modified polyethylene fiber.

[0016] Further, the modified elastomer is prepared by the following steps:

[0017] B1. Place 1,5-diaminopentane, ethyl acetate and triethylamine in a reaction kettle protected by a nitrogen atmosphere, cool down to 5 - 10 °C, add methacryloyl chloride, keep warm and react for 20 - 22 h, and perform post-treatment to obtain intermediate Ⅰ;

[0018] Reaction formula for the preparation of intermediate Ⅰ is:

[0019]

[0020] The preparation reaction principle of Intermediate Ⅰ is as follows:

[0021] During the reaction process, methacryloyl chloride, as a strong electrophilic reagent, attacks the amino group of 1,5-diaminopentane to form an amide bond. Triethylamine, as an acid-binding agent, forms salts with the generated hydrochloric acid, promoting the forward reaction to obtain Intermediate Ⅰ. The mass spectrometry data of Intermediate Ⅰ is m / z: 238.14 (100.0%), 239.14 (15.1%), 240.14 (1.4%).

[0022] B2. Place poly-1,4-butanediol bis(4-aminobenzoate), ethyl acetate, and triethylamine in a reaction kettle protected by a nitrogen atmosphere, cool down to 5 - 10 °C, add methacryloyl chloride, keep the temperature for reaction for 20 - 22 h, and perform post-treatment to obtain Intermediate Ⅱ;

[0023] The preparation reaction formula of Intermediate Ⅱ is as follows:

[0024]

[0025] The preparation reaction principle of Intermediate Ⅱ is as follows:

[0026] During the reaction process, methacryloyl chloride, as a strong electrophilic reagent, attacks the amino group of poly-1,4-butanediol bis(4-aminobenzoate) to form an amide bond. Triethylamine, as an acid-binding agent, forms salts with the generated hydrochloric acid, promoting the forward reaction to obtain Intermediate Ⅱ.

[0027] B3. Place Intermediate Ⅰ, Intermediate Ⅱ, and ethyl acetate in a reaction kettle protected by a nitrogen atmosphere, stir for 1 - 5 min, add 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) and triazene, heat up to 45 - 55 °C, keep the temperature for reaction for 20 - 22 h, and perform post-treatment to obtain the modified elastomer.

[0028] The preparation reaction formula of the modified elastomer is as follows:

[0029]

[0030] Wherein:

[0031] The preparation reaction principle of the modified elastomer is as follows:

[0032] During the reaction process, the mercapto group of 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) attacks the olefin double bond of Intermediate Ⅰ and Intermediate Ⅱ, the double bond breaks, and a thioether bond is formed to obtain the modified elastomer with a block structure.

[0033] Further, in step B1, the dosage ratio of 1,5-diaminopentane, ethyl acetate, triethylamine and methacryloyl chloride is 1 - 1.5 g: 30 - 50 mL: 2 - 3 g: 2 - 4 g. The post-treatment steps include: after the reaction is completed, when the reaction solution cools to room temperature, deionized water and ethyl acetate are added, and extraction is carried out 1 - 2 times. The organic phase is transferred to a rotary evaporator at a temperature of 50 - 60 °C and rotated until no liquid is collected to obtain intermediate I; in step B2, the dosage ratio of poly-1,4-butanediol bis(4-aminobenzoate), ethyl acetate, triethylamine and methacryloyl chloride is 10 - 12 g: 100 - 150 mL: 4 - 6 g: 3 - 4 g. The post-treatment steps include: after the reaction is completed, when the reaction solution cools to room temperature, deionized water and ethyl acetate are added, and extraction is carried out 1 - 2 times. The organic phase is transferred to a rotary evaporator at a temperature of 50 - 60 °C and rotated until no liquid is collected to obtain intermediate II; in step B2, the dosage ratio of intermediate I, intermediate II, ethyl acetate, 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) and triazene is 5 - 10 g: 1 - 2 g: 100 - 150 mL: 2 - 4 g: 0.2 - 0.5 g. The post-treatment steps include: after the reaction is completed, the reaction solution is transferred to a rotary evaporator at a temperature of 50 - 60 °C and rotated until no liquid is collected to obtain the modified elastomer.

[0034] Further, the modified blowing agent is prepared by the following steps:

[0035] C1. Place azodicarbonamide, zinc oxide, zinc stearate and absolute ethanol in a reaction kettle and ultrasonically disperse for 20 - 30 min to obtain a mixed solution;

[0036] C2. Place the mixed solution in a reaction kettle, add ammonia water, stir for 15 - 30 min, add tetraethyl orthosilicate and absolute ethanol, stir for 20 - 24 h, and perform post-treatment to obtain the modified blowing agent.

[0037] The reaction principle for the preparation of the modified blowing agent is:

[0038] During the reaction process, under the catalysis of ammonia water, tetraethyl orthosilicate hydrolyzes to form hydroxylated silicic acid and alcohol. The silicic acids undergo a condensation reaction to form a colloidal mixture. A hydrogen bond interaction is formed between the amide group of azodicarbonamide in the mixed solution and the hydroxyl group of silicic acid, and a three-dimensional network structure of silicon is formed on the surface of azodicarbonamide to obtain the modified blowing agent;

[0039] The mechanism of action of the modified blowing agent is:

[0040] After azodicarbonamide is activated by zinc oxide and zinc stearate, its thermal decomposition temperature is reduced to below 180°C. During the vulcanization process of rubber when the temperature rises, azodicarbonamide decomposes to produce nitrogen and carbon dioxide, enabling the simultaneous vulcanization and foaming of rubber, and finally obtaining a rubber composite sole with a uniform bubble structure.

[0041] Furthermore, in step C1, the dosage ratio of azodicarbonamide, zinc oxide, zinc stearate, and absolute ethanol is 5 - 7 g : 0.3 - 0.5 g : 0.1 - 0.2 g : 50 - 80 mL; in step C2, the dosage ratio of the mixed solution, ammonia water, tetraethyl orthosilicate, and absolute ethanol is 60 - 80 mL : 6 - 7 mL : 6 - 8 mL : 10 - 15 mL. The post-treatment steps include: after the reaction is completed, perform suction filtration, wash the filter cake with absolute ethanol 2 - 3 times, transfer the filter cake to a drying oven at a temperature of 60 - 80°C, and dry it to room temperature to obtain the modified foaming agent.

[0042] The present invention also provides a preparation method for a wear-resistant and highly elastic rubber composite sole, including the following steps:

[0043] S1. Place ethylene propylene diene monomer (EPDM) rubber on a two-roll mill, plastify for 10 - 15 min, and shear to obtain an EPDM rubber strip;

[0044] S2. Place the EPDM rubber strip in an internal mixer, heat up to 85 - 95°C, knead for 1 - 2 min, add the modified elastomer and the modified foaming agent, and knead for 1 - 2 min to obtain a kneaded mixed rubber;

[0045] S3. Place the kneaded mixed rubber on a two-roll mill, plastify for 1 - 2 min, add the modified polyethylene fiber and the auxiliary additive, and thin pass 3 - 6 times to obtain a mixed rubber;

[0046] S4. Inject the mixed rubber into a calender and calender it into a sheet to obtain a rubber sheet;

[0047] S5. After placing the rubber sheet in a mold, transfer it to a vulcanization instrument, heat up to 160 - 180°C, vulcanize for 30 - 60 min, and foam to obtain a rubber composite sole.

[0048] The present invention has the following beneficial effects:

[0049] 1. The present invention is to deposit nano silicon dioxide with nucleation performance in azodicarbonamide by a sol-gel method to obtain a modified foaming agent, to perform plasma treatment on the surface of polyethylene fiber to obtain pretreated polyethylene fiber, and then to graft polyethyleneimine on the surface of the pretreated polyethylene fiber with dopamine as a crosslinking agent to obtain a modified polyethylene fiber, to prepare a modified elastomer with a block structure by using poly-1,4-butanediol bis(4-aminobenzoate) as a soft segment, 1,5-diaminopentane as a hard segment, and 2,2'-(1,2-ethylenedioxy)bisethylmercaptan as a chain extender, to use ethylene propylene diene monomer rubber as a base material, to use modified polyethylene fiber, modified elastomer and modified foaming agent as reinforcing agents, and to use auxiliary additives as processing aids. The modified polyethylene fiber prepared by the present invention generates oxygen-containing functional groups such as carboxyl and hydroxyl on the surface of the polyethylene fiber through plasma excitation, thereby increasing the reaction sites of the polyethylene fiber, further forming a polydopamine film on the fiber surface through dopamine self-polymerization, depositing polyethyleneimine through chemical reaction and physical action, and introducing amino groups. These oxygen-containing functional groups and amino groups can form stronger binding force with the rubber matrix through hydrogen bonds, ionic bonds or covalent bonds, thereby improving the mechanical properties and wear resistance of the rubber composite fiber, and the polyethylene fiber itself has high strength and modulus, which can greatly improve the tensile strength and tear resistance of the rubber sole, so that the sole is not easy to break or tear when subjected to external force impact.

[0050] 2. The present invention activates azodicarbonamide by adding zinc oxide and zinc stearate, wherein zinc oxide, as a metal oxide, can weaken the NN bond energy in the azodicarbonamide molecule through electron transfer, thereby causing it to decompose and produce gas at a lower temperature; meanwhile, zinc oxide nanoparticles have a high specific surface area, can provide more active sites, and accelerate the uniform release of nitrogen during the decomposition of azodicarbonamide; zinc stearate, as a metal soap substance, wraps azodicarbonamide through its amphiphilic molecular structure, thereby improving its dispersion uniformity in ethanol; and the decomposition temperature of zinc stearate is between the activation temperature of azodicarbonamide and the processing temperature of the resin, and during mixing The rubber composite sole plays a buffering role in the rubber stage to prevent local overheating from causing premature decomposition of the foaming agent. Nano-silica is used as a nucleating agent and is evenly loaded on the surface of azodicarbonamide through a sol-gel method to provide high-density nucleation sites, which promotes the synchronous and uniform generation of bubbles in the rubber matrix. The pore size is reduced from millimeter level to micron level, which significantly reduces the phenomenon of large bubbles or combined bubbles. The uniform pore structure reduces internal defects of the material, so that the rubber matrix can effectively disperse the load when subjected to force, thereby improving the mechanical properties of the rubber composite sole. At the same time, the fine pores provide a more uniform deformation space during compression, and the energy loss during the rebound process is reduced, thereby improving the elastic performance of the rubber composite sole.

[0051] 3. The present invention also uses poly-1,4-butanediol bis(4-aminobenzoate) as the soft segment, 1,5-diaminopentane as the hard segment, and 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) as the chain extender to prepare a modified elastomer with a block structure. The hard segment forms high-density amide bonds using 1,4-butanediamine, strengthens the material through hydrogen bond networks and crystalline regions, and improves the tensile strength of the rubber composite sole. The soft segment restricts the free rotation of molecular chains by introducing a benzene ring structure, endows the soft segment with rigid-like characteristics, and achieves a balance between elasticity and strength. At the same time, soft chain segments such as polyethers have good affinity with ethylene-propylene-diene monomer (EPDM) rubber, improving the interfacial compatibility of the matrix. The high amide bond content forms dynamic hydrogen bond crosslinking. When stressed or worn, the hydrogen bonds break and can spontaneously recombine after removing the external force, achieving microcrack repair and improving the wear resistance of the rubber composite sole. The elastomer network and the foaming agent form an "interlocking structure of rigid skeleton - flexible pores", improving the elasticity of the rubber composite sole. At the same time, it constructs a "rigid-flexible armor" interface with the modified fiber, and improves the wear resistance and mechanical properties of the rubber composite sole through fiber mechanical anchoring and elastomer wrapping effects. Detailed implementation manners

[0052] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] The ethylene-propylene-diene monomer (EPDM) rubber used in the present invention is purchased from Guangzhou Degao New Materials Co., Ltd., and the model is 4039;

[0054] The Tris buffer solution used in the present invention is purchased from Guangzhou Hewei Medical Technology Co., Ltd., and the pH is 8.5;

[0055] The polyethylene fiber used in the present invention is purchased from Guangdong Teweilong New Materials Application Co., Ltd., and the length is 3 - 18 mm.

[0056] Example 1

[0057] This example provides a preparation method for a wear-resistant and highly elastic rubber composite sole, including the following steps:

[0058] S1. Prepare modified polyethylene fiber

[0059] Place the polyethylene fiber in a vacuum plasma chamber for plasma treatment to obtain pretreated polyethylene fiber;

[0060] The vacuum pressure for plasma treatment is 30 Pa, the power is 100 W, the gas introduced is oxygen, and the treatment time is 20 S;

[0061] Weigh: 50 g of dopamine, 30 mL of Tris buffer solution, 10000 mL of deionized water and 50 g of polyethyleneimine and place them in a reaction kettle, stir for 1 min, add pretreated polyethylene fiber for impregnation, the impregnation ratio is 1:30, heat up to 20 °C, keep the temperature for reaction for 18 h, after the reaction is completed, carry out suction filtration, wash the filter cake with deionized water and ethanol once, transfer it to a drying oven at 50 °C, dry to room temperature to obtain modified polyethylene fiber.

[0062] S2. Prepare modified elastomer

[0063] Weigh: 10 g of 1,5-diaminopentane, 300 mL of ethyl acetate and 20 g of triethylamine and place them in a reaction kettle protected by a nitrogen atmosphere, cool down to 5 °C, add 20 g of methacryloyl chloride, keep the temperature for reaction for 20 h, after the reaction is completed, wait for the reaction solution to cool down to room temperature, add deionized water and ethyl acetate, extract once, transfer the organic phase to a rotary evaporator at 50 °C, rotate until no liquid is collected to obtain intermediate Ⅰ;

[0064] Weigh: 100 g of poly-1,4-butylene glycol bis(4-aminobenzoate), 1000 mL of ethyl acetate and 40 g of triethylamine and place them in a reaction kettle protected by a nitrogen atmosphere, cool down to 5 °C, add 30 g of methacryloyl chloride, keep the temperature for reaction for 20 h, after the reaction is completed, wait for the reaction solution to cool down to room temperature, add deionized water and ethyl acetate, extract once, transfer the organic phase to a rotary evaporator at 50 °C, rotate until no liquid is collected to obtain intermediate Ⅱ;

[0065] Weigh: 50 g of intermediate Ⅰ, 10 g of intermediate Ⅱ and 1000 mL of ethyl acetate and place them in a reaction kettle protected by a nitrogen atmosphere, stir for 1 min, add 20 g of 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) and 2 g of triazene, heat up to 45 °C, keep the temperature for reaction for 20 h, after the reaction is completed, transfer the reaction solution to a rotary evaporator at 50 °C, rotate until no liquid is collected to obtain modified elastomer.

[0066] S3. Prepare modified blowing agent

[0067] Weigh: 50 g of azodicarbonamide, 3 g of zinc oxide, 1 g of zinc stearate and 500 mL of absolute ethanol and place them in a reaction kettle, carry out ultrasonic dispersion for 20 min to obtain a mixed solution;

[0068] Weigh: 600 mL of the mixed solution and place it in a reaction kettle, add 60 mL of ammonia water, stir for 15 min, add 60 mL of tetraethyl orthosilicate and 100 mL of absolute ethanol, stir for 20 h, after the reaction is completed, carry out suction filtration, wash the filter cake with absolute ethanol twice, transfer the filter cake to a drying oven at 60 °C, dry to room temperature to obtain modified blowing agent.

[0069] S4. Prepare rubber composite sole

[0070] Mix dioctyl phthalate, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-nitrosodiphenylamine, dibenzothiazole disulfide and sulfur evenly according to the mass ratio of 5:2:1:10:2 to obtain an auxiliary additive for standby;

[0071] Weigh by mass parts: 80 parts of ethylene propylene diene monomer rubber, 3 parts of modified polyethylene fiber, 12 parts of modified elastomer, 5 parts of modified foaming agent and 10 parts of auxiliary additive;

[0072] Place the ethylene propylene diene monomer rubber in a two-roll open mill, plasticize for 10 min, and shear to obtain an ethylene propylene diene monomer rubber strip;

[0073] Place the ethylene propylene diene monomer rubber strip in an internal mixer, heat up to 85 °C, mix for 1 min, add the modified elastomer and the modified foaming agent, and mix for 1 min to obtain a mixed internal mixer rubber;

[0074] Place the mixed internal mixer rubber in a two-roll open mill, plasticize for 1 min, add the modified polyethylene fiber and the auxiliary additive, and thin pass 3 times to obtain a mixed rubber;

[0075] Inject the mixed rubber into a calender and calender it into a sheet to obtain a rubber sheet;

[0076] After placing the rubber sheet in a mold, transfer it to a vulcanization instrument, heat up to 160 °C, vulcanize for 30 min, and foam to obtain a rubber composite sole.

[0077] Example 2

[0078] This example provides a preparation method of a wear-resistant and highly elastic rubber composite sole, including the following steps:

[0079] S1. Prepare modified polyethylene fiber

[0080] Place the polyethylene fiber in a vacuum plasma chamber for plasma treatment to obtain pretreated polyethylene fiber;

[0081] The vacuum pressure of the plasma treatment is 35 Pa, the power is 110 W, the gas introduced is oxygen, and the treatment time is 25 S;

[0082] Weigh: 65 g of dopamine, 40 mL of Tris buffer solution, 12500 mL of deionized water and 65 g of polyethyleneimine, place them in a reaction kettle, stir for 3 min, add the pretreated polyethylene fiber for impregnation, the impregnation ratio is 1:32, heat up to 25 °C, keep warm and react for 19 h. After the reaction is completed, carry out suction filtration, wash the filter cake with deionized water and ethanol twice, transfer it to a drying oven at 60 °C, and dry it to room temperature to obtain the modified polyethylene fiber.

[0083] S2. Prepare modified elastomer

[0084] Weigh: 12.5 g of 1,5-diaminopentane, 400 mL of ethyl acetate and 25 g of triethylamine and place them in a reaction kettle protected by a nitrogen atmosphere. Cool down to 7 °C, add 30 g of methacryloyl chloride, keep the temperature for reaction for 21 h. After the reaction is completed, wait for the reaction solution to cool to room temperature, add deionized water and ethyl acetate, extract twice, transfer the organic phase to a rotary evaporator at 55 °C, and rotate until no liquid is collected to obtain Intermediate I;

[0085] Weigh: 110 g of poly-1,4-butanediol bis(4-aminobenzoate), 1250 mL of ethyl acetate and 50 g of triethylamine and place them in a reaction kettle protected by a nitrogen atmosphere. Cool down to 7 °C, add 35 g of methacryloyl chloride, keep the temperature for reaction for 21 h. After the reaction is completed, wait for the reaction solution to cool to room temperature, add deionized water and ethyl acetate, extract twice, transfer the organic phase to a rotary evaporator at 55 °C, and rotate until no liquid is collected to obtain Intermediate II;

[0086] Weigh: 75 g of Intermediate I, 15 g of Intermediate II and 1250 mL of ethyl acetate and place them in a reaction kettle protected by a nitrogen atmosphere. Stir for 3 min, add 30 g of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) and 3 g of triazene, heat up to 50 °C, keep the temperature for reaction for 21 h. After the reaction is completed, transfer the reaction solution to a rotary evaporator at 55 °C, and rotate until no liquid is collected to obtain the modified elastomer.

[0087] S3. Prepare the modified blowing agent

[0088] Weigh: 60 g of azodicarbonamide, 4 g of zinc oxide, 1.5 g of zinc stearate and 700 mL of absolute ethanol and place them in a reaction kettle, ultrasonically disperse for 25 min to obtain a mixed solution;

[0089] Weigh: 700 mL of the mixed solution and place it in a reaction kettle, add 65 mL of ammonia water, stir for 25 min, add 70 mL of tetraethyl orthosilicate and 125 mL of absolute ethanol, stir for 22 h. After the reaction is completed, perform suction filtration, wash the filter cake with absolute ethanol three times, transfer the filter cake to a drying oven at 70 °C, and dry to room temperature to obtain the modified blowing agent.

[0090] S4. Prepare the rubber composite sole

[0091] Mix dioctyl phthalate, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-nitrosodiphenylamine, dibenzothiazole disulfide and sulfur evenly according to the mass ratio of 5:2:1:10:2 to obtain the auxiliary additive, and set aside;

[0092] Weigh by mass parts: 90 parts of ethylene propylene diene monomer rubber, 4 parts of modified polyethylene fiber, 13.5 parts of modified elastomer, 5.5 parts of modified foaming agent and 11 parts of auxiliary additive;

[0093] Place the ethylene propylene diene monomer rubber in a two-roll mill, plasticize for 12 min, shear, and obtain an ethylene propylene diene monomer rubber strip;

[0094] Place the ethylene propylene diene monomer rubber strip in an internal mixer, heat up to 90 °C, mix for 2 min, add the modified elastomer and the modified foaming agent, and mix for 2 min to obtain a mixed internal-mixed rubber;

[0095] Place the mixed internal-mixed rubber in a two-roll mill, plasticize for 2 min, add the modified polyethylene fiber and the auxiliary additive, and thin pass 5 times to obtain a mixed rubber;

[0096] Inject the mixed rubber into a calender, calender it into a sheet to obtain a rubber sheet;

[0097] After placing the rubber sheet in a mold, transfer it to a vulcanization instrument, heat up to 170 °C, vulcanize for 45 min, and foam to obtain a rubber composite sole.

[0098] Example 3

[0099] This example provides a preparation method of a wear-resistant and highly elastic rubber composite sole, including the following steps:

[0100] S1. Prepare modified polyethylene fiber

[0101] Place the polyethylene fiber in a vacuum plasma chamber, perform plasma treatment to obtain pretreated polyethylene fiber;

[0102] The vacuum pressure of the plasma treatment is 40 Pa, the power is 120 W, the gas introduced is oxygen, and the treatment time is 30 s;

[0103] Weigh: 80 g of dopamine, 50 mL of Tris buffer solution, 15000 mL of deionized water and 80 g of polyethyleneimine, place them in a reaction kettle, stir for 5 min, add the pretreated polyethylene fiber for impregnation, the impregnation ratio is 1:35, heat up to 30 °C, keep warm and react for 20 h. After the reaction is completed, perform suction filtration, wash the filter cake with deionized water and ethanol twice, transfer it to a drying oven at 70 °C, and dry to room temperature to obtain the modified polyethylene fiber.

[0104] S2. Prepare modified elastomer

[0105] Weigh: 15 g of 1,5-diaminopentane, 500 mL of ethyl acetate and 30 g of triethylamine and place them in a reaction kettle protected by a nitrogen atmosphere. Cool down to 10 °C, add 40 g of methacryloyl chloride, and keep the temperature for reaction for 22 h. After the reaction is completed, wait for the reaction solution to cool to room temperature, add deionized water and ethyl acetate, and extract twice. Transfer the organic phase to a rotary evaporator at 60 °C and rotate until no liquid is collected to obtain Intermediate I;

[0106] Weigh: 120 g of poly-1,4-butylene glycol bis(4-aminobenzoate), 1500 mL of ethyl acetate and 60 g of triethylamine and place them in a reaction kettle protected by a nitrogen atmosphere. Cool down to 10 °C, add 40 g of methacryloyl chloride, and keep the temperature for reaction for 22 h. After the reaction is completed, wait for the reaction solution to cool to room temperature, add deionized water and ethyl acetate, and extract twice. Transfer the organic phase to a rotary evaporator at 60 °C and rotate until no liquid is collected to obtain Intermediate II;

[0107] Weigh: 100 g of Intermediate I, 20 g of Intermediate II and 1500 mL of ethyl acetate and place them in a reaction kettle protected by a nitrogen atmosphere. Stir for 5 min, add 40 g of 2,2'-(1,2-ethanediyl dioxy)bis(ethanethiol) and 5 g of triazene, heat up to 55 °C, and keep the temperature for reaction for 22 h. After the reaction is completed, transfer the reaction solution to a rotary evaporator at 60 °C and rotate until no liquid is collected to obtain the modified elastomer.

[0108] S3. Prepare the modified blowing agent

[0109] Weigh: 70 g of azodicarbonamide, 5 g of zinc oxide, 2 g of zinc stearate and 800 mL of absolute ethanol and place them in a reaction kettle, and ultrasonically disperse for 30 min to obtain a mixed solution;

[0110] Weigh: 800 mL of the mixed solution and place it in a reaction kettle, add 70 mL of ammonia water, stir for 30 min, add 80 mL of tetraethyl orthosilicate and 150 mL of absolute ethanol, stir for 24 h. After the reaction is completed, filter by suction, wash the filter cake with absolute ethanol three times, transfer the filter cake to a drying oven at 80 °C, and dry to room temperature to obtain the modified blowing agent.

[0111] S4. Prepare the rubber composite sole

[0112] Mix dioctyl phthalate, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-nitrosodiphenylamine, dibenzothiazole disulfide and sulfur evenly according to the mass ratio of 5:2:1:10:2 to obtain the auxiliary additive for standby;

[0113] Weigh by mass parts: 100 parts of ethylene-propylene-diene monomer rubber, 5 parts of modified polyethylene fiber, 15 parts of modified elastomer, 6 parts of modified blowing agent and 12 parts of auxiliary additive;

[0114] Place the ethylene propylene diene monomer (EPDM) rubber in a two-roll mill, plasticate for 15 min, shear, and obtain an EPDM rubber strip.

[0115] Place the EPDM rubber strip in an internal mixer, heat up to 95 °C, mix for 2 min, add the modified elastomer and the modified blowing agent, and mix for 2 min to obtain a mixed rubber compound.

[0116] Place the mixed rubber compound in a two-roll mill, plasticate for 2 min, add the modified polyethylene fiber and the auxiliary additive, and thin pass 6 times to obtain a kneaded rubber compound.

[0117] Inject the kneaded rubber compound into a calender, calender it into a sheet to obtain a rubber sheet.

[0118] Put the rubber sheet into a mold, then transfer it to a vulcanization instrument, heat up to 180 °C, vulcanize for 60 min, and foam to obtain a rubber composite sole.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 2 is that during the preparation of the rubber composite sole used in this comparative example, the pretreated polyethylene fiber prepared in Step S1 is used to equally replace the modified polyethylene fiber.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 2 is that during the preparation of the rubber composite sole used in this comparative example, the use of the modified elastomer is cancelled.

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 2 is that during the preparation of the rubber composite sole used in this comparative example, the use of the modified blowing agent is cancelled.

[0125] Performance test:

[0126] Refer to the standard GB / T531.1 - 2008 "Rubber, vulcanized or thermoplastic - Determination of indentation hardness - Part 1: Durometer method (Shore hardness)" to test the Shore hardness of the rubber composite soles prepared in Examples 1 - 3 and Comparative Examples 1 - 3.

[0127] Refer to the standard GB / T 9867 - 2008 "Rubber, vulcanized or thermoplastic - Determination of abrasion resistance (rotary roller abrasion testing machine method)" to test the abrasion resistance of the rubber composite soles prepared in Examples 1 - 3 and Comparative Examples 1 - 3, with a travel of 40 m.

[0128] The tensile strength and elongation at break of the rubber composite soles prepared in Examples 1-3 and Comparative Examples 1-3 were tested with reference to the standard GB / T 528-2009 "Rubber, vulcanized or thermoplastic - Determination of tensile stress - strain properties".

[0129] The tear strength of the rubber composite soles prepared in Examples 1-3 and Comparative Examples 1-3 was tested with reference to the standard GB / T 529-2008 "Rubber, vulcanized or thermoplastic - Determination of tear strength (trouser, right angle and crescent test pieces)".

[0130] The elastic modulus of the rubber composite soles prepared in Examples 1-3 and Comparative Examples 1-3 was tested with reference to the standard HG / T 3321-2012 "Rubber, vulcanized - Method for determination of elastic modulus", and the specific data are shown in Table 1.

[0131] Table 1 - Performance test data table of each sample

[0132]

[0133]

[0134] Data analysis:

[0135] By comparing and analyzing the data in Table 1, it can be found that the Shore hardness of the rubber composite sole prepared in the present invention is 45.1 Shore A, the volume abrasion is 162.4 mm 3 , the tensile strength is 31.5 MPa, the tear strength is 36.4 kN·m -1 and the elongation at break is 534.8% while the elastic modulus is 24.1 MPa, and all the data are better than those of the comparative examples;

[0136] By comparing the data of Example 2 and Comparative Example 1, it can be found that the Shore hardness, volume abrasion, tensile strength, tear strength, elongation at break and elastic modulus of Comparative Example 1 are significantly reduced, indicating that the modified polyethylene fiber prepared in the present invention forms a polydopamine film on the fiber surface through dopamine self - polymerization, and further deposits polyethyleneimine through chemical and physical reactions, introducing amino groups. These oxygen - containing functional groups and amino groups can form stronger binding forces with the rubber matrix through hydrogen bonds, ionic bonds or covalent bonds, thereby improving the mechanical properties and wear resistance of the rubber composite fiber. Moreover, the polyethylene fiber itself has high strength and modulus, which can greatly improve the tensile strength and tear resistance of the rubber sole, making the sole not easily break or tear when subjected to external force impact;

[0137] By comparing the data of Example 2 and Comparative Example 2, it can be found that the volume abrasion, tensile strength, tear strength and elongation at break of Comparative Example 2 are significantly reduced, while the Shore hardness and elastic modulus are increased. This shows that the present invention prepares a modified elastomer with a block structure by using poly-1,4-butanediol bis(4-aminobenzoate) as the soft segment, 1,5-diaminopentane as the hard segment, and 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) as the chain extender. The hard segment forms high-density amide bonds with 1,4-butanediamine, strengthens the material through the hydrogen bond network and crystal regions, and improves the tensile strength of the rubber composite sole. The soft segment introduces a benzene ring structure to restrict the free rotation of the molecular chain, endows the soft segment with a quasi-rigid characteristic, and realizes the balance of elasticity and strength. At the same time, soft chain segments such as polyethers have good affinity with ethylene propylene diene monomer rubber, improving the interfacial compatibility of the matrix. The high amide bond content forms dynamic hydrogen bond crosslinks. When stressed or worn, the hydrogen bonds break and can spontaneously reorganize after removing the external force, realizing microcrack repair and improving the wear resistance of the rubber composite sole. The elastomer network and the blowing agent form an interlocked structure of "rigid skeleton-flexible pores", improving the elasticity of the rubber composite sole. At the same time, it constructs a "rigid-flexible armor" interface with the modified fiber, and improves the wear resistance and mechanical properties of the rubber composite sole through fiber mechanical anchoring and elastomer wrapping effects;

[0138] By comparing the data of Example 3 and Comparative Example 2, it can be found that the volume abrasion, tensile strength, tear strength and elongation at break of Comparative Example 3 are significantly reduced, while the Shore hardness and elastic modulus are increased. This shows that the present invention activates azodicarbonamide by adding zinc oxide and zinc stearate. Among them, zinc oxide, as a metal oxide, can weaken the N-N bond energy in the azodicarbonamide molecule through electron transfer, promoting its decomposition and gas generation at a lower temperature. At the same time, zinc oxide nanoparticles have a high specific surface area, providing more active sites to accelerate the uniform release of nitrogen during the decomposition of azodicarbonamide. Zinc stearate, as a metal soap substance, wraps azodicarbonamide through its amphiphilic molecular structure, improving its dispersion uniformity in ethanol. And the decomposition temperature of zinc stearate is between the activation temperature of azodicarbonamide and the resin processing temperature, playing a buffering role in the mixing stage to prevent premature decomposition of the blowing agent caused by local overheating. Nano-silica, as a nucleating agent, is uniformly loaded on the surface of azodicarbonamide by the sol-gel method, providing high-density nucleation sites, promoting the synchronous and uniform generation of bubbles in the rubber matrix, reducing the cell size from millimeter level to micron level, significantly reducing the phenomenon of large bubbles or merged bubbles. The uniform cell structure reduces internal defects in the material, enabling the rubber matrix to effectively disperse the load when stressed, improving the mechanical properties of the rubber composite sole. At the same time, the fine cells provide a more uniform deformation space during compression, reducing the energy loss during the rebound process and improving the elastic properties of the rubber composite sole.

[0139] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only the specific embodiments. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A wear-resistant and highly elastic rubber composite sole, comprising EPDM rubber and auxiliary additives, characterized in that: Also included are modified polyethylene fibers, modified foaming agents, and modified elastomers; The polyethylene fiber is placed in a vacuum plasma chamber for plasma treatment to obtain pretreated polyethylene fiber, dopamine, Tris buffer, deionized water and polyethyleneimine are placed in a reaction kettle, stirred for 1-5 minutes, the pretreated polyethylene fiber is added for impregnation, the temperature is raised to 20-30° C., the temperature is kept for reaction for 18-20 hours, and the modified polyethylene fiber is obtained by post-treatment; Among them, 1,5-diaminopentane, ethyl acetate and triethylamine are placed in a reactor protected by a nitrogen atmosphere, cooled to 5-10°C, methacryloyl chloride is added, and the reaction is kept warm for 20-22 hours, and the intermediate I is obtained by post-treatment. Poly-1,4-butanediol bis(4-aminobenzoate), ethyl acetate and triethylamine are placed in a reactor protected by a nitrogen atmosphere, cooled to 5-10°C, methacryloyl chloride is added, and the reaction is kept warm for 20-22 hours, and the intermediate II is obtained by post-treatment. Intermediate I, intermediate II and ethyl acetate are placed in a reactor protected by a nitrogen atmosphere, stirred for 1-5 minutes, 2,2'-(1,2-ethylenedioxy)bisethanethiol and triazine are added, the temperature is raised to 45-55°C, the reaction is kept warm for 20-22 hours, and the modified elastomer is obtained by post-treatment. The method comprises the following steps: placing azodicarbonamide, zinc oxide, zinc stearate and anhydrous ethanol in a reaction kettle, performing ultrasonic dispersion for 20-30 minutes to obtain a mixed solution, placing the mixed solution in a reaction kettle, adding ammonia water, stirring for 15-30 minutes, adding tetraethyl orthosilicate and anhydrous ethanol, stirring for 20-24 hours, and performing post-treatment to obtain a modified foaming agent; By weight, 80-100 parts of EPDM rubber, 10-12 parts of auxiliary additives, 3-5 parts of modified polyethylene fibers, 5-6 parts of modified foaming agents and 12-15 parts of modified elastomers are processed to prepare the wear-resistant and highly elastic rubber composite sole.

2. The wear-resistant and highly elastic rubber composite sole according to claim 1, characterized in that: The auxiliary additives are composed of a plasticizer, an antioxidant, a scorch inhibitor, a vulcanizer and an accelerator in a mass ratio of 5:2:1:10:

2.

3. The wear-resistant and highly elastic rubber composite sole according to claim 1, characterized in that: The vacuum pressure of the plasma treatment is 30-40 Pa, the power is 100-120 W, the gas introduced is oxygen, and the treatment time is 20-30 seconds.

4. The wear-resistant and highly elastic rubber composite sole according to claim 1, characterized in that: The dosage ratio of dopamine, Tris buffer, deionized water and polyethyleneimine is 5-8 g:3-5 mL:1000-1500 mL:5-8 g, and the impregnation ratio is 1:30-35.

5. The wear-resistant and highly elastic rubber composite sole according to claim 1, characterized in that: The usage ratio of the 1,5-diaminopentane, ethyl acetate, triethylamine and methacryloyl chloride is 1-1.5 g: 30-50 mL: 2-3 g: 2-4 g.

6. The wear-resistant and highly elastic rubber composite sole according to claim 1, characterized in that: The dosage ratio of the poly-1,4-butanediol bis(4-aminobenzoate), ethyl acetate, triethylamine and methacryloyl chloride is 10-12g:100-150mL:4-6g:3-4g; the dosage ratio of the intermediate I, intermediate II, ethyl acetate, 2,2'-(1,2-ethylenedioxy)bisethylmercaptan and triazine ene is 5-10g:1-2g:100-150mL:2-4g:0.2-0.5g.

7. The wear-resistant and highly elastic rubber composite sole according to claim 1, characterized in that: The dosage ratio of the azodicarbonamide, zinc oxide, zinc stearate and anhydrous ethanol is 5-7g:0.3-0.5g:0.1-0.2g:50-80mL; the dosage ratio of the mixed solution, ammonia water, tetraethyl orthosilicate and anhydrous ethanol is 60-80mL:6-7mL:6-8mL:10-15mL.

8. The method for preparing a wear-resistant and highly elastic rubber composite sole according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Place the EPDM rubber in a double-roll mill, plasticate for 10-15 minutes, and shear to obtain an EPDM rubber strip; S2, placing the EPDM rubber strip in an internal mixer, heating it to 85-95°C, mixing it for 1-2 minutes, adding the modified elastomer and the modified foaming agent, mixing it for 1-2 minutes, and obtaining a mixed rubber; S3, placing the mixed rubber on a double-roll mill, plasticating for 1-2 minutes, adding modified polyethylene fiber and auxiliary additives, and thinning for 3-6 times to obtain a mixed rubber; S4, injecting the mixed rubber into a calender and calendering it into a sheet to obtain a rubber sheet; S5. After placing the rubber sheet into the mold, transfer it to a vulcanizer, raise the temperature to 160-180° C., vulcanize for 30-60 minutes, and foam to obtain the wear-resistant and highly elastic rubber composite sole.

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