High-bonding-strength rubber particle for runway and preparation method of high-bonding-strength rubber particle

Abstract

The invention relates to the technical field of runway materials, in particular to rubber particles with high bonding strength for a runway and a preparation method of the rubber particles, and aims to solve the problems that existing rubber particles are low in bonding strength and not tight enough in bonding, and cracks and particle falling are easily caused on the surface of the runway. Modified rubber is used as a matrix, active hydroxyl is introduced on a main chain through free radical reaction, polarity and reactivity of the rubber are improved, terminal hydroxyl is converted into primary amino which can react with isocyanate groups in a polyurethane adhesive to generate firm urea bonds, chemical bonding is achieved, and bonding performance is improved; the rubber particles chemically react with the glue through the surface active layer, the peel strength is improved after the rubber particles are combined with the runway glue, the problems of frosting, bulging and short service life of the runway surface are reduced, the weather resistance of the particles and the bonding interface of the particles and the glue is good, high elasticity and bonding force can be kept for a long time, and the overall service life of the runway is prolonged.

Description

Technical Field

[0001] This invention relates to the field of runway material technology, specifically to a rubber granule for runways with high bonding strength and its preparation method. Background Technology

[0002] In the field of sports facilities, the running track serves as the foundation for athletes to conduct long-distance running, sprinting, relay running, and other sports. The choice of materials for the running track directly affects the safety and effectiveness of the sports. Traditional running track materials mainly use rubber as the main component because rubber has good elasticity and wear resistance, and can provide good support and shock absorption.

[0003] Existing rubber granules have certain limitations in terms of bonding strength, meaning that the bonds between the rubber granules are not tight enough, which can easily lead to cracks or granule detachment on the track surface, seriously affecting the track's aesthetics and performance.

[0004] Therefore, the rubber granules for running tracks with high bonding strength and the preparation method thereof of the present invention are of great significance in the field of running track material technology. Summary of the Invention

[0005] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a rubber granule for running tracks with high bonding strength and a method for preparing the same, which solves the problems of low bonding strength and insufficient bonding between existing rubber granules, which easily lead to cracks and granule detachment on the running track surface.

[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a rubber granule for running tracks with high bonding strength, comprising the following components in parts by weight: 2-4 parts natural rubber, 8-10 parts carboxylated nitrile rubber, 4-5 parts chloroprene rubber, 10-15 parts modified rubber, 0.5 parts zinc oxide, 1 part stearic acid, 1-2 parts vulcanizing agent, 10-15 parts reinforcing agent, 0.5 parts antioxidant, and 1-2 parts plasticizer. The carboxylated nitrile rubber is designated as XNBR N641; the chloroprene rubber is designated as HDM-CR122; the vulcanizing aid is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1-1.5g:0.3-0.5g:1.5-2g; the reinforcing aid is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 9-11g:2-3g:0.3-0.5g; the antioxidant is one or more of antioxidants 4020 and RD; and the plasticizer is an aromatic oil.

[0007] In a preferred embodiment of the present invention, the modified rubber is prepared by the following steps: Step a1: Add hydroxyl-terminated liquid nitrile rubber and chlorobenzene to a three-necked flask equipped with a stirrer and thermometer. Mix and stir in an 80°C oil bath for 1-2 hours. Under nitrogen protection, cool to 40°C and add ethylene glycol vinyl ether dropwise at a rate of 1 mL / min. Stir at a constant temperature for 30 minutes. Add the first portion of benzoyl peroxide and maintain the reaction temperature for 1 hour. Raise the temperature to 60°C, add the second portion of benzoyl peroxide, and maintain the reaction temperature for 1-2 hours. Raise the temperature to 70°C, add the third portion of benzoyl peroxide, and maintain the reaction temperature for 2-3 hours. After the reaction is complete, immerse the flask in an ice-water bath. Cool to 5-10℃, add hydroquinone, stir for 15 min, add to anhydrous ethanol at -20℃, stir to flocculate, let stand for 1 h, decant the supernatant, collect the flocculent, extract in a Soxhlet extractor for 48 h, and dry in a vacuum oven at 40℃ for 48 h to obtain grafted modified nitrile rubber; the first part of benzoyl peroxide accounts for 1 / 3 of the total amount of benzoyl peroxide; the second part of benzoyl peroxide accounts for 1 / 3 of the total amount of benzoyl peroxide; the third part of benzoyl peroxide accounts for 1 / 3 of the total amount of benzoyl peroxide. Step a2: Add the grafted modified nitrile rubber and the first portion of dichloromethane to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 40°C for 4 hours. Transfer to an ice-water bath at 0-5°C and add benzenesulfonyl chloride and triethylamine at a rate of 1 mL / min. Raise the temperature to 25°C and stir under nitrogen protection for 10-12 hours. Add the first portion of n-heptane and stir for 15 minutes. Transfer to a rotary evaporator and concentrate under reduced pressure in a 30°C water bath. Add the second portion of n-heptane and mix and stir for 15 minutes. Let stand for 1-2 hours. Centrifuge at 10000 r / min for 15 minutes. Discard the supernatant and dry under vacuum at 30°C for 6 hours. Add the second portion of dichloromethane. Alkane was added dropwise with diamine solution at 0.5 mL / min at 0℃, the temperature was raised to 25℃, and the reaction was stirred in the dark for 24-48 h. Dilute hydrochloric acid solution was added, and the mixture was stirred for 30 min. The mixture was separated, and the organic phase was washed 2-3 times with distilled water. The mixture was purified by alumina column chromatography, and a mixed solvent was added. The mixture was centrifuged, washed 2-3 times with distilled water, and dried in a vacuum oven at 40℃ for 24 h to obtain the intermediate product. The first part of dichloromethane accounted for 3 / 4 of the total amount of dichloromethane; the second part of dichloromethane accounted for 1 / 4 of the total amount of dichloromethane; the first part of n-heptane accounted for 1 / 10 of the total amount of n-heptane; and the second part of n-heptane accounted for 9 / 10 of the total amount of n-heptane. Step a3: Add the intermediate product and acetone to a three-necked flask equipped with a stirrer and thermometer, sonicate for 15-20 min, filter, place the filter cake in a plasma cleaner, introduce oxygen, treat at 100-200W power for 1-3 min, and dry in a 60℃ vacuum oven for 2-3 h to obtain the activated product; add the ethanol solution to a beaker, adjust the pH to 4.5-5.5 with glacial acetic acid, add the silane coupling agent, mix and stir at 25℃ for 1-2 h, let stand for 30 min to obtain the hydrolysate; immerse the activated product in the hydrolysate for 1-3 min, remove, dry at 25℃ for 30 min, and place in an oven at 110-120℃ for 1-2 h to cure to obtain the modified rubber.

[0008] In a preferred embodiment of the present invention, the ratio of the amount of the hydroxyl-terminated liquid nitrile rubber, chlorobenzene, ethylene glycol vinyl ether, total benzoyl peroxide, hydroquinone, and anhydrous ethanol in step a1 is 40-50g; 400-450mL: 8-10mL: 0.1-0.3g: 0.1g: 1000-1500mL; the hydroxyl-terminated liquid nitrile rubber is produced in Tangyi and has the brand name TL910.

[0009] In a preferred embodiment of the present invention, the ratio of the amount of grafted modified nitrile rubber, total amount of dichloromethane, benzenesulfonyl chloride, triethylamine, total amount of n-heptane, diamine solution, dilute hydrochloric acid solution, and mixed solvent in step a2 is 20-30g: 200-300mL: 3-5mL: 3-5mL: 500-550mL: 50-60mL: 100-150mL: 500mL; the mass fraction of the diamine solution is 4-8%; the solute of the diamine solution is one of 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, and 1,10-decanediamine; the solvent of the diamine solution is dichloromethane; the mass fraction of the dilute hydrochloric acid solution is 5%; and the mixed solution is prepared by mixing diethyl ether and anhydrous ethanol in a volume ratio of 1:1.

[0010] In a preferred embodiment of the present invention, the ratio of the intermediate product, acetone, ethanol solution and silane coupling agent in step a3 is 20-30g: 100-150mL: 200mL: 4-5g; the mass fraction of the ethanol solution is 95%; and the type of the silane coupling agent is KH-550.

[0011] Secondly, this application provides a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step 1: Weigh out 2-4 parts of natural rubber, 8-10 parts of carboxylated nitrile rubber, 4-5 parts of chloroprene rubber, 10-15 parts of modified rubber, 0.5 parts of zinc oxide, 1 part of stearic acid, 1-2 parts of vulcanizing agent, 10-15 parts of reinforcing agent, 0.5 parts of antioxidant, and 1-2 parts of plasticizer according to the following weight proportions. Step 2: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a mixer at 50-60℃ and plasticize for 3-5 minutes. Add zinc oxide and stearic acid and mix for 2-3 minutes. Add reinforcing agents and plasticizers, and control the discharge temperature at 110-125℃. Discharge the rubber onto a two-roll mill at 40-50℃, and pass it through a triangular loop and a thin pass 3-5 times. Sheet the rubber and allow it to cool naturally to 25℃ to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 40-50℃, add modified rubber, and pass it through a thin pass and a triangular loop 2-3 times. At 80-90℃, add vulcanizing agents, cut and turn the rubber with left and right cutters, fill it into a mold, and place it in a flat vulcanizing machine. Vulcanize at 160℃ and 10-15MPa for 10-15 minutes, and allow it to cool naturally to 25℃. Crush the vulcanizing machine to obtain rubber granules with high bonding strength for running tracks.

[0012] The beneficial effects of this invention are: This invention discloses a high-adhesion rubber granule for running tracks and its preparation method. The method involves plasticizing natural rubber, carboxylated nitrile rubber, and chloroprene rubber, adding zinc oxide and stearic acid, adding reinforcing agents and plasticizers, discharging the mixture onto a two-roll mill, forming triangular shavings, thinning, sheeting, and cooling to obtain a masterbatch. The masterbatch is then thinned on the two-roll mill, modified rubber is added, thinned again, formed triangular shavings, vulcanization aids are added, the mixture is cut and turned, filled into a mold, vulcanized in a flat vulcanizing machine, cooled, and crushed to obtain high-adhesion rubber granules for running tracks. The rubber granules of this invention undergo a chemical reaction with the adhesive through a surface-active layer, resulting in improved peel strength after bonding with the running track adhesive. This reduces problems such as surface sanding, blistering, and shortened lifespan on the running track. The granules themselves and the bonding interface with the adhesive exhibit good weather resistance, maintaining high elasticity and adhesion for a long time, thus extending the overall service life of the running track.

[0013] In the preparation of high-adhesion rubber granules for running tracks, modified rubber was first prepared. Benzoyl peroxide decomposed upon heating to generate free radicals, which abstracted hydrogen from the rubber backbone or monomers, initiating a chain reaction. This caused the monomer polymer to be covalently bonded to the rubber chain. Under the initiation of benzoyl peroxide, the double bond of ethylene glycol vinyl ether opened and was grafted onto the backbone of hydroxyl-terminated liquid nitrile butadiene rubber via a free radical reaction, introducing active hydroxyl groups. The hydroxyl-containing side chains were then grafted onto the rubber molecules, increasing the polarity and reactivity of the rubber. The batch addition of benzoyl peroxide and gradient heating effectively suppressed explosive polymerization and gelation, ensuring a stable and controllable grafting reaction. The terminal hydroxyl groups reacted with benzenesulfonyl chloride to generate highly reactive sulfonate esters. The sulfonate esters then underwent a nucleophilic substitution reaction with diamines, converting the terminal groups into highly reactive primary amino groups. Hydroxyl groups are converted into primary amino groups that can react with isocyanate groups in polyurethane adhesives to form strong urea bonds, achieving chemical bonding and improving adhesion performance. Oxygen plasma bombards the surface of intermediate products, etching and introducing oxygen-containing polar groups to increase surface energy and roughness. The silanol generated by the hydrolysis of silane coupling agent condenses with hydroxyl groups on the activated surface to form Si-OC bonds, which self-condense to form a network structure, forming a coating on the particle surface. Plasma treatment enhances surface energy, allowing the liquid polyurethane adhesive to better wet and spread. The increased roughness strengthens the mechanical interlocking effect. The silane layer provides some protection to the internal rubber matrix, improving water resistance and resistance to media corrosion. The outermost silane layer can form a strong bond with the polyurethane adhesive immediately, enhancing interfacial bonding and achieving high bonding strength and runway durability. Attached Figure Description

[0014] The invention will now be further described with reference to the accompanying drawings.

[0015] Figure 1 This is a schematic diagram showing the tensile strength test results of the rubber particles used in the running track in Examples 1-3 and Comparative Examples 1-3 of this invention.

[0016] Figure 2 This is a schematic diagram showing the test results of the elongation at break of the rubber particles used for running tracks in Examples 1-3 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1:

[0019] This embodiment describes a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step S1: Add 40g of hydroxyl-terminated liquid nitrile rubber TL910 and 400mL of chlorobenzene to a three-necked flask equipped with a stirrer and thermometer. Mix and stir in an 80℃ oil bath for 1h. Under nitrogen protection, cool to 40℃ and add 8mL of ethylene glycol vinyl ether dropwise at a rate of 1mL / min. Stir at a constant temperature for 30min, add 0.03g of benzoyl peroxide, maintain the reaction temperature for 1h, raise the temperature to 60℃, and add 0.03g of benzoyl peroxide. The reaction was kept at a constant temperature for 1 hour, then heated to 70°C, and 0.03 g of benzoyl peroxide was added. The reaction was kept at a constant temperature for 2 hours. After the reaction was completed, the mixture was immersed in an ice-water bath to cool to 5°C. 0.1 g of hydroquinone was added, and the mixture was stirred for 15 minutes. The mixture was then added to 1000 mL of anhydrous ethanol at -20°C, stirred to flocculate, and allowed to stand for 1 hour. The supernatant was discarded, the flocculent was collected, and the mixture was extracted in a Soxhlet extractor for 48 hours. The mixture was then dried in a vacuum oven at 40°C for 48 hours to obtain grafted modified nitrile rubber. Step S2: Add 20g of grafted modified nitrile rubber and 150mL of dichloromethane to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 40℃ for 4h. Transfer to an ice-water bath at 0℃ and add 3mL of benzenesulfonyl chloride and 3mL of triethylamine at a rate of 1mL / min. Raise the temperature to 25℃ and stir under nitrogen protection for 10h. Add 50mL of n-heptane and stir for 15min. Transfer to a rotary evaporator and concentrate under reduced pressure in a 30℃ water bath. Add 450mL of n-heptane and mix and stir for 15min. Let stand for 1h. Centrifuge at 10000r / min for 15min. Discard the supernatant. Dry under vacuum at 30℃ for 6h. Add 50mL of dichloromethane and add 50mL dropwise at 0℃ at a rate of 0.5mL / min. A 1,3-propanediamine solution was heated to 25°C and stirred in the dark for 24 hours. 100 mL of a 5% (w / w) dilute hydrochloric acid solution was added, and the mixture was stirred for 30 minutes. The mixture was separated, and the organic phase was washed twice with distilled water. Purification was performed by alumina column chromatography. 500 mL of a mixed solvent was added, and the mixture was centrifuged, washed twice with distilled water, and dried in a vacuum oven at 40°C for 24 hours to obtain the intermediate product. The solvent for the 1,3-propanediamine solution was dichloromethane. The mixed solution was prepared by mixing diethyl ether and anhydrous ethanol in a 1:1 volume ratio. Step S3: Add 20g of intermediate product and 100mL of acetone to a three-necked flask equipped with a stirrer and thermometer, sonicate for 15min, filter, place the filter cake in a plasma cleaner, introduce oxygen, treat at 100W power for 1min, and dry in a 60℃ vacuum oven for 2h to obtain the activated product; add 200mL of 95% ethanol solution to a beaker, adjust the pH to 4.5 with glacial acetic acid, add 4g of silane coupling agent KH-550, mix and stir at 25℃ for 1h, let stand for 30min to obtain the hydrolysate; immerse the activated product in the hydrolysate for 1min, remove, dry at 25℃ for 30min, place in an oven at 110℃ and cure for 1h to obtain the modified rubber; Step S4: Weigh out 2 parts by weight of natural rubber, 8 parts by weight of carboxylated nitrile rubber XNBR N641, 4 parts by weight of chloroprene rubber HDM-CR122, 10 parts by weight of modified rubber, 0.5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1 part by weight of vulcanizing agent, 10 parts by weight of reinforcing agent, 0.5 parts by weight of antioxidant 4020, and 1 part by weight of aromatic oil; the vulcanizing agent is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1g:0.3g:1.5g; the reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 9g:2g:0.3g. Step S5: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a 50°C internal mixer and plasticize for 3 minutes. Add zinc oxide and stearic acid and mix for 2 minutes. Add reinforcing agents and plasticizers, control the discharge temperature at 110°C, discharge the rubber onto a two-roll mill at 40°C, and pass it through a triangular loop and a thin pass 3 times. Sheet the rubber and allow it to cool naturally to 25°C to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 40°C, add modified rubber, and pass it through a thin pass and a triangular loop twice. Add vulcanizing agents at 80°C, cut and turn the rubber with left and right cutters, fill the mold, and place it in a flat vulcanizing machine. Vulcanize at 160°C and 10MPa for 10 minutes, allow it to cool naturally to 25°C, and crush it with a crusher to obtain rubber granules for running tracks with high bonding strength.

[0020] Example 2:

[0021] This embodiment describes a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step S1: Add 45g of hydroxyl-terminated liquid nitrile rubber TL910 and 425mL of chlorobenzene to a three-necked flask equipped with a stirrer and thermometer. Mix and stir in an 80℃ oil bath for 1.5h. Under nitrogen protection, cool to 40℃ and add 9mL of ethylene glycol vinyl ether dropwise at a rate of 1mL / min. Stir at a constant temperature for 30min, add 0.05g of benzoyl peroxide, and maintain the reaction temperature for 1h. Raise the temperature to 60℃ and add 0.05g of benzoyl peroxide. The reaction was carried out at a warm temperature for 1.5 h, then heated to 70 °C, and 0.05 g of benzoyl peroxide was added. The reaction was maintained at this temperature for 2.5 h. After the reaction was completed, the mixture was immersed in an ice-water bath to cool to 8 °C, and 0.1 g of hydroquinone was added. The mixture was stirred for 15 min, and then added to 1250 mL of anhydrous ethanol at -20 °C. The mixture was stirred and flocculated. After standing for 1 h, the supernatant was discarded, the flocculent was collected, and extracted in a Soxhlet extractor for 48 h. The mixture was then dried in a vacuum oven at 40 °C for 48 h to obtain grafted modified nitrile rubber. Step S2: Add 25g of grafted modified nitrile rubber and 200mL of dichloromethane to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 40℃ for 4h. Transfer to an ice-water bath at 3℃ and add 4mL of benzenesulfonyl chloride and 4mL of triethylamine at a rate of 1mL / min. Raise the temperature to 25℃ and stir under nitrogen protection for 11h. Add 53mL of n-heptane and stir for 15min. Transfer to a rotary evaporator and concentrate under reduced pressure in a 30℃ water bath. Add 470mL of n-heptane and mix and stir for 15min. Let stand for 1.5h. Centrifuge at 10000r / min for 15min. Discard the supernatant. Dry under vacuum at 30℃ for 6h. Add 60mL of dichloromethane and add 55mL of dichloromethane dropwise at 0℃ at a rate of 0.5mL / min. A 1,3-propanediamine solution was heated to 25°C and stirred in the dark for 36 hours. 125 mL of a 5% (w / w) dilute hydrochloric acid solution was added, and the mixture was stirred for 30 minutes. The mixture was separated, and the organic phase was washed three times with distilled water. Purification was performed by alumina column chromatography. 500 mL of a mixed solvent was added, and the mixture was centrifuged, washed three times with distilled water, and dried in a vacuum oven at 40°C for 24 hours to obtain the intermediate product. The solvent for the 1,3-propanediamine solution was dichloromethane. The mixed solution was prepared by mixing diethyl ether and anhydrous ethanol in a 1:1 volume ratio. Step S3: Add 25g of intermediate product and 125mL of acetone to a three-necked flask equipped with a stirrer and thermometer, sonicate for 18min, filter, place the filter cake in a plasma cleaner, introduce oxygen, treat at 150W power for 2min, and dry in a 60℃ vacuum oven for 2.5h to obtain the activated product; add 200mL of 95% ethanol solution to a beaker, adjust the pH to 5 with glacial acetic acid, add 4.5g of silane coupling agent KH-550, mix and stir at 25℃ for 1.5h, let stand for 30min to obtain the hydrolysate; immerse the activated product in the hydrolysate for 2min, remove, dry at 25℃ for 30min, place in an oven at 115℃ and cure for 1.5h to obtain the modified rubber; Step S4: Weigh out 3 parts by weight of natural rubber, 9 parts by weight of carboxylated nitrile rubber XNBR N641, 4.5 parts by weight of chloroprene rubber HDM-CR122, 13 parts by weight of modified rubber, 0.5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1.5 parts by weight of vulcanizing agent, 13 parts by weight of reinforcing agent, 0.5 parts by weight of antioxidant 4020, and 1.5 parts by weight of aromatic oil; the vulcanizing agent is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1.3g:0.4g:1.8g; the reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 10g:2.5g:0.4g. Step S5: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a 55°C internal mixer and plasticize for 4 minutes. Add zinc oxide and stearic acid and mix for 3 minutes. Add reinforcing agents and plasticizers, control the discharge temperature at 120°C, discharge the rubber onto a two-roll mill at 45°C, and pass it through a triangular loop and a thin pass 4 times. Sheet the rubber and allow it to cool naturally to 25°C to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 45°C, add modified rubber, and pass it through a thin pass and a triangular loop 3 times. Add vulcanizing agents at 85°C, cut and turn the rubber with left and right cutters, fill the mold, and place it in a flat vulcanizing machine. Vulcanize at 160°C and 13MPa for 13 minutes, allow it to cool naturally to 25°C, and crush it with a crusher to obtain rubber granules for running tracks with high bonding strength.

[0022] Example 3:

[0023] This embodiment describes a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step S1: Add 50g of hydroxyl-terminated liquid nitrile rubber TL910 and 450mL of chlorobenzene to a three-necked flask equipped with a stirrer and thermometer. Mix and stir in an oil bath at 80℃ for 2 hours. Under nitrogen protection, cool to 40℃ and add 10mL of ethylene glycol vinyl ether dropwise at a rate of 1mL / min. Stir at a constant temperature for 30 minutes, add 0.1g of benzoyl peroxide, maintain the reaction temperature for 1 hour, raise the temperature to 60℃, and add 0.1g of benzoyl peroxide. The reaction was kept at a constant temperature for 2 hours, then heated to 70°C, and 0.1 g of benzoyl peroxide was added. The reaction was kept at a constant temperature for 3 hours. After the reaction was completed, the mixture was immersed in an ice-water bath to cool to 10°C. 0.1 g of hydroquinone was added, and the mixture was stirred for 15 minutes. The mixture was then added to 1500 mL of anhydrous ethanol at -20°C, stirred to flocculate, and allowed to stand for 1 hour. The supernatant was discarded, the flocculent was collected, and the mixture was extracted in a Soxhlet extractor for 48 hours. The mixture was then dried in a vacuum oven at 40°C for 48 hours to obtain grafted modified nitrile rubber. Step S2: Add 30g of grafted modified nitrile rubber and 225mL of dichloromethane to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 40℃ for 4h. Transfer to an ice-water bath at 5℃ and add 5mL of benzenesulfonyl chloride and 5mL of triethylamine at a rate of 1mL / min. Raise the temperature to 25℃ and stir under nitrogen protection for 12h. Add 55mL of n-heptane and stir for 15min. Transfer to a rotary evaporator and concentrate under reduced pressure in a 30℃ water bath. Add 495mL of n-heptane and mix and stir for 15min. Let stand for 2h. Centrifuge at 10000r / min for 15min. Discard the supernatant. Dry under vacuum at 30℃ for 6h. Add 75mL of dichloromethane and add 60mL of dichloromethane dropwise at 0℃ at a rate of 0.5mL / min. A 1,3-propanediamine solution was heated to 25°C and stirred in the dark for 48 hours. 150 mL of a 5% (w / w) dilute hydrochloric acid solution was added, and the mixture was stirred for 30 minutes. The mixture was separated, and the organic phase was washed three times with distilled water. Purification was performed by alumina column chromatography. 500 mL of a mixed solvent was added, and the mixture was centrifuged, washed three times with distilled water, and dried in a vacuum oven at 40°C for 24 hours to obtain the intermediate product. The solvent for the 1,3-propanediamine solution was dichloromethane. The mixed solution was prepared by mixing diethyl ether and anhydrous ethanol in a 1:1 volume ratio. Step S3: Add 30g of intermediate product and 150mL of acetone to a three-necked flask equipped with a stirrer and thermometer, sonicate for 20min, filter, place the filter cake in a plasma cleaner, introduce oxygen, treat at 200W power for 3min, and dry in a 60℃ vacuum oven for 3h to obtain the activated product; add 200mL of 95% ethanol solution to a beaker, adjust the pH to 5.5 with glacial acetic acid, add 5g of silane coupling agent KH-550, mix and stir at 25℃ for 2h, let stand for 30min to obtain the hydrolysate; immerse the activated product in the hydrolysate for 3min, remove, dry at 25℃ for 30min, place in a 120℃ oven and cure for 2h to obtain the modified rubber; Step S4: Weigh out 4 parts by weight of natural rubber, 10 parts by weight of carboxylated nitrile rubber XNBR N641, 5 parts by weight of chloroprene rubber HDM-CR122, 15 parts by weight of modified rubber, 0.5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 2 parts by weight of vulcanizing agent, 15 parts by weight of reinforcing agent, 0.5 parts by weight of antioxidant 4020, and 2 parts by weight of aromatic oil; the vulcanizing agent is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1.5g:0.5g:2g; the reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 11g:3g:0.5g. Step S5: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a 60°C internal mixer and plasticize for 5 minutes. Add zinc oxide and stearic acid and mix for 3 minutes. Add reinforcing agents and plasticizers, control the discharge temperature to 125°C, discharge the rubber onto a two-roll mill at 50°C, and pass it through a triangular loop and a thin pass 5 times. Sheet the rubber and allow it to cool naturally to 25°C to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 50°C, add modified rubber, and pass it through a thin pass and a triangular loop 3 times. Add vulcanizing agents at 90°C, cut and turn the rubber with left and right cutters, fill the mold, and place it in a flat vulcanizing machine. Vulcanize at 160°C and 15MPa for 15 minutes, allow it to cool naturally to 25°C, and crush it with a crusher to obtain rubber granules for running tracks with high bonding strength.

[0024] Comparative Example 1: This comparative example illustrates a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step S1: Weigh out 3 parts by weight of natural rubber, 9 parts by weight of carboxylated nitrile rubber XNBR N641, 4.5 parts by weight of chloroprene rubber HDM-CR122, 13 parts by weight of hydroxyl-terminated liquid nitrile rubber TL910, 0.5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1.5 parts by weight of vulcanizing agent, 13 parts by weight of reinforcing agent, 0.5 parts by weight of antioxidant 4020, and 1.5 parts by weight of aromatic oil; the vulcanizing agent is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1.3g:0.4g:1.8g; the reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 10g:2.5g:0.4g. Step S2: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a 55°C internal mixer and plasticize for 4 minutes. Add zinc oxide and stearic acid and mix for 3 minutes. Add reinforcing agents and plasticizers, control the discharge temperature at 120°C, discharge the rubber onto a two-roll mill at 45°C, and pass it through a triangular loop and a thin pass 4 times. Sheet the rubber and allow it to cool naturally to 25°C to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 45°C, add hydroxyl-terminated liquid nitrile rubber TL910, and pass it through a thin pass and a triangular loop 3 times. Add vulcanizing agents at 85°C, cut and turn the rubber with left and right cutters, fill the mold, and place it in a flat vulcanizing machine. Vulcanize at 160°C and 13MPa for 13 minutes, allow it to cool naturally to 25°C, and crush it with a crusher to obtain rubber granules for running tracks with high bonding strength.

[0025] Comparative Example 2: This comparative example illustrates a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step S1: Add 45g of hydroxyl-terminated liquid nitrile rubber TL910 and 425mL of chlorobenzene to a three-necked flask equipped with a stirrer and thermometer. Mix and stir in an 80℃ oil bath for 1.5h. Under nitrogen protection, cool to 40℃ and add 9mL of ethylene glycol vinyl ether dropwise at a rate of 1mL / min. Stir at a constant temperature for 30min, add 0.05g of benzoyl peroxide, and maintain the reaction temperature for 1h. Raise the temperature to 60℃ and add 0.05g of benzoyl peroxide. The reaction was carried out at a warm temperature for 1.5 h, then heated to 70 °C, and 0.05 g of benzoyl peroxide was added. The reaction was maintained at this temperature for 2.5 h. After the reaction was completed, the mixture was immersed in an ice-water bath to cool to 8 °C, and 0.1 g of hydroquinone was added. The mixture was stirred for 15 min, and then added to 1250 mL of anhydrous ethanol at -20 °C. The mixture was stirred and flocculated. After standing for 1 h, the supernatant was discarded, the flocculent was collected, and extracted in a Soxhlet extractor for 48 h. The mixture was then dried in a vacuum oven at 40 °C for 48 h to obtain grafted modified nitrile rubber. Step S2: Add 25g of grafted modified nitrile rubber and 125mL of acetone to a three-necked flask equipped with a stirrer and thermometer. Sonicate for 18min, filter, place the filter cake in a plasma cleaner, introduce oxygen, treat at 150W power for 2min, and dry in a 60℃ vacuum oven for 2.5h to obtain the activated product. Add 200mL of 95% ethanol solution to a beaker, adjust the pH to 5 with glacial acetic acid, add 4.5g of silane coupling agent KH-550, mix and stir at 25℃ for 1.5h, let stand for 30min to obtain the hydrolysate. Immerse the activated product in the hydrolysate for 2min, remove, dry at 25℃ for 30min, and place in an oven at 115℃ for 1.5h to cure to obtain the modified rubber. Step S3: Weigh out 3 parts by weight of natural rubber, 9 parts by weight of carboxylated nitrile rubber XNBR N641, 4.5 parts by weight of chloroprene rubber HDM-CR122, 13 parts by weight of modified rubber, 0.5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1.5 parts by weight of vulcanizing agent, 13 parts by weight of reinforcing agent, 0.5 parts by weight of antioxidant 4020, and 1.5 parts by weight of aromatic oil; the vulcanizing agent is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1.3g:0.4g:1.8g; the reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 10g:2.5g:0.4g. Step S4: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a 55°C internal mixer and plasticize for 4 minutes. Add zinc oxide and stearic acid and mix for 3 minutes. Add reinforcing agents and plasticizers, control the discharge temperature at 120°C, discharge the rubber onto a two-roll mill at 45°C, and pass it through a triangular loop and a thin pass 4 times. Sheet the rubber and allow it to cool naturally to 25°C to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 45°C, add modified rubber, and pass it through a thin pass and a triangular loop 3 times. Add vulcanizing agents at 85°C, cut and turn the rubber with left and right cutters, fill the mold, and place it in a flat vulcanizing machine. Vulcanize at 160°C and 13MPa for 13 minutes, allow it to cool naturally to 25°C, and crush it with a crusher to obtain rubber granules for running tracks with high bonding strength.

[0026] Comparative Example 3: This comparative example illustrates a method for preparing rubber granules for running tracks with high bonding strength, comprising the following steps: Step S1: Add 25g of hydroxyl-terminated liquid nitrile rubber TL910 and 200mL of dichloromethane to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 40℃ for 4h. Transfer to an ice-water bath at 3℃ and add 4mL of benzenesulfonyl chloride and 4mL of triethylamine at a rate of 1mL / min. Raise the temperature to 25℃ and stir under nitrogen protection for 11h. Add 53mL of n-heptane and stir for 15min. Transfer to a rotary evaporator and concentrate under reduced pressure in a 30℃ water bath. Add 470mL of n-heptane and mix and stir for 15min. Let stand for 1.5h. Centrifuge at 10000r / min for 15min. Discard the supernatant. Dry under vacuum at 30℃ for 6h. Add 60mL of dichloromethane and add 55mL of dichloromethane dropwise at 0℃ at a rate of 0.5mL / min. A 1,3-propanediamine solution was heated to 25°C and stirred in the dark for 36 hours. 125 mL of a 5% (w / w) dilute hydrochloric acid solution was added, and the mixture was stirred for 30 minutes. The mixture was separated, and the organic phase was washed three times with distilled water. Purification was performed by alumina column chromatography. 500 mL of a mixed solvent was added, and the mixture was centrifuged, washed three times with distilled water, and dried in a vacuum oven at 40°C for 24 hours to obtain the intermediate product. The solvent for the 1,3-propanediamine solution was dichloromethane. The mixed solution was prepared by mixing diethyl ether and anhydrous ethanol in a 1:1 volume ratio. Step S2: Add 25g of intermediate product and 125mL of acetone to a three-necked flask equipped with a stirrer and thermometer, sonicate for 18min, filter, place the filter cake in a plasma cleaner, introduce oxygen, treat at 150W power for 2min, and dry in a 60℃ vacuum oven for 2.5h to obtain the activated product; add 200mL of 95% ethanol solution to a beaker, adjust the pH to 5 with glacial acetic acid, add 4.5g of silane coupling agent KH-550, mix and stir at 25℃ for 1.5h, let stand for 30min to obtain the hydrolysate; immerse the activated product in the hydrolysate for 2min, remove, dry at 25℃ for 30min, place in an oven at 115℃ and cure for 1.5h to obtain the modified rubber; Step S3: Weigh out 3 parts by weight of natural rubber, 9 parts by weight of carboxylated nitrile rubber XNBR N641, 4.5 parts by weight of chloroprene rubber HDM-CR122, 13 parts by weight of modified rubber, 0.5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1.5 parts by weight of vulcanizing agent, 13 parts by weight of reinforcing agent, 0.5 parts by weight of antioxidant 4020, and 1.5 parts by weight of aromatic oil; the vulcanizing agent is a mixture of accelerator CZ, accelerator DM, and sulfur in a mass ratio of 1.3g:0.4g:1.8g; the reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 10g:2.5g:0.4g. Step S4: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a 55°C internal mixer and plasticize for 4 minutes. Add zinc oxide and stearic acid and mix for 3 minutes. Add reinforcing agents and plasticizers, control the discharge temperature at 120°C, discharge the rubber onto a two-roll mill at 45°C, and pass it through a triangular loop and a thin pass 4 times. Sheet the rubber and allow it to cool naturally to 25°C to obtain the masterbatch. Pass the masterbatch through a two-roll mill at 45°C, add modified rubber, and pass it through a thin pass and a triangular loop 3 times. Add vulcanizing agents at 85°C, cut and turn the rubber with left and right cutters, fill the mold, and place it in a flat vulcanizing machine. Vulcanize at 160°C and 13MPa for 13 minutes, allow it to cool naturally to 25°C, and crush it with a crusher to obtain rubber granules for running tracks with high bonding strength.

[0027] The high-bonding-strength rubber granules for running tracks prepared in Examples 1-3 and Comparative Examples 1-3 were mixed with PU adhesive JT-3008 at a weight ratio of rubber granules:adhesive = 6:1. The mixture was then added to a molding die and hot-pressed for 10 minutes to obtain a running track granule layer sample. The tensile strength and elongation at break of the sample were tested according to standard GB 36246-2018. The test results are as follows: Figure 1-2 As shown: Comparing Examples 1-3 with Comparative Examples 1-3: From Example 1 to Example 3, the amount of raw materials gradually increases, more monomers are grafted onto the rubber chain, and the rubber carries more polar hydroxyl functional groups, which improves the affinity with the adhesive and converts hydroxyl groups into highly reactive amino groups. Longer reaction times and excess diamine lead to a higher concentration of terminal amino groups in the rubber chain, enhancing its ability to form high-strength urea bonds with the isocyanate groups in the PU adhesive, thus gradually improving performance. Comparing Example 2 with Comparative Example 1, it can be seen that the rubber particles in Comparative Example 1 only contain terminal hydroxyl groups, have weak polarity and low reactivity, and mainly form weak van der Waals forces and mechanical interlocking with the PU adhesive. The particle surface of Example 2 is rich in highly reactive amino groups, which can react with the isocyanate groups of PU. The ester groups undergo covalent bonding reactions to form urea bonds, improving the adhesion performance. Comparing Example 2 with Comparative Example 2, it can be seen that: Comparative Example 2 only underwent grafting and silane treatment, while the particle surface of Example 2 is rich in highly active amino groups. The reactivity of hydroxyl groups with isocyanate groups is much lower than that of amino groups, and the bond strength of the urethane bond is lower than that of the urea bond. Therefore, the performance of Comparative Example 2 is lower than that of Example 2. Comparing Example 2 with Comparative Example 3, it can be seen that: Comparative Example 3 directly subjected the rubber particles to amination and silane treatment. The unmodified rubber backbone has poor compatibility with the non-polar matrix rubber, and the modified rubber is unevenly dispersed in the matrix. Under stress, the stress cannot be effectively transferred from the matrix rubber to the active amino groups of the modified particles through the interface, resulting in lower performance than that of Example 2.

[0028] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A type of rubber granule for running tracks with high bonding strength, characterized in that, Includes the following components by weight: 2-4 parts natural rubber, 8-10 parts carboxylated nitrile rubber, 4-5 parts chloroprene rubber, 10-15 parts modified rubber, 0.5 parts zinc oxide, 1 part stearic acid, 1-2 parts vulcanizing agent, 10-15 parts reinforcing agent, 0.5 parts antioxidant, and 1-2 parts plasticizer. The modified rubber is prepared by the following steps: Step a1: Mix hydroxyl-terminated liquid nitrile rubber and chlorobenzene, add ethylene glycol vinyl ether dropwise, stir, add the first part of benzoyl peroxide and react, heat up, add the second part of benzoyl peroxide and react, heat up, add the third part of benzoyl peroxide and react, cool, add hydroquinone and stir, add to anhydrous ethanol, stir to flocculate, let stand, put the flocculent into a Soxhlet extractor for extraction, vacuum dry to obtain grafted modified nitrile rubber; Step a2: Mix the grafted modified nitrile rubber and the first portion of dichloromethane, add benzenesulfonyl chloride and triethylamine, and heat to react; add the first portion of n-heptane and stir, concentrate under reduced pressure, add the second portion of n-heptane, mix and stir, let stand, centrifuge, discard the supernatant, vacuum dry, add the second portion of dichloromethane, add diamine solution dropwise, heat, stir to react in the dark, add dilute hydrochloric acid solution and stir, separate the liquid, wash the organic phase with distilled water, purify by alumina column chromatography, add mixed solvent, centrifuge, wash, vacuum dry to obtain the intermediate product; Step a3: The intermediate product and acetone are ultrasonically treated, filtered, and the filter cake is placed in a plasma cleaner for treatment and vacuum dried to obtain the activated product; ethanol solution is added to a beaker, pH is adjusted, silane coupling agent is added and stirred, and allowed to stand to obtain hydrolysate; the activated product is immersed in the hydrolysate, taken out and dried in the sun, and placed in an oven for curing to obtain modified rubber.

2. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, The carboxylated nitrile butadiene rubber is of type XNBR N641; the chloroprene rubber is of type HDM-CR122; the vulcanization aid is a mixture of accelerator CZ, accelerator DM and sulfur in a mass ratio of 1-1.5g: 0.3-0.5g: 1.5-2g.

3. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, The reinforcing agent is a mixture of carbon black N330, silica, and silane coupling agent Si-69 in a mass ratio of 9-11g:2-3g:0.3-0.5g; the antioxidant is one or more of antioxidant 4020 and antioxidant RD; and the plasticizer is aromatic oil.

4. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, In step a1, the ratio of the amount of the hydroxyl-terminated liquid nitrile rubber, chlorobenzene, ethylene glycol vinyl ether, total benzoyl peroxide, hydroquinone, and anhydrous ethanol is 40-50g: 400-450mL: 8-10mL: 0.1-0.3g: 0.1g: 1000-1500mL; the grade of the hydroxyl-terminated liquid nitrile rubber is TL910.

5. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, In step a1, the first portion of benzoyl peroxide accounts for 1 / 3 of the total amount of benzoyl peroxide; the second portion of benzoyl peroxide accounts for 1 / 3 of the total amount of benzoyl peroxide; and the third portion of benzoyl peroxide accounts for 1 / 3 of the total amount of benzoyl peroxide.

6. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, In step a2, the ratio of the amount of grafted modified nitrile rubber, total dichloromethane, benzenesulfonyl chloride, triethylamine, total n-heptane, diamine solution, dilute hydrochloric acid solution, and mixed solvent is 20-30g: 200-300mL: 3-5mL: 3-5mL: 500-550mL: 50-60mL: 100-150mL: 500mL; the mass fraction of the diamine solution is 4-8%.

7. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, The solute in the diamine solution in step a2 is one of 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, and 1,10-decanediamine; the solvent of the diamine solution is dichloromethane; the mass fraction of the dilute hydrochloric acid solution is 5%; and the mixed solution is prepared by mixing diethyl ether and anhydrous ethanol at a volume ratio of 1:

1.

8. The rubber granules for running tracks with high bonding strength according to claim 1, characterized in that, In step a2, the first part of dichloromethane accounts for 3 / 4 of the total amount of dichloromethane; the second part of dichloromethane accounts for 1 / 4 of the total amount of dichloromethane; the first part of n-heptane accounts for 1 / 10 of the total amount of n-heptane; and the second part of n-heptane accounts for 9 / 10 of the total amount of n-heptane.

9. A rubber granule for running tracks with high bonding strength according to claim 1, characterized in that, The ratio of the intermediate product, acetone, ethanol solution, and silane coupling agent in step a3 is 20-30g: 100-150mL: 200mL: 4-5g; the ethanol solution has a mass fraction of 95%; and the silane coupling agent is KH-550.

10. A method for preparing high-bonding-strength rubber granules for running tracks as described in any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Weigh out 2-4 parts of natural rubber, 8-10 parts of carboxylated nitrile rubber, 4-5 parts of chloroprene rubber, 10-15 parts of modified rubber, 0.5 parts of zinc oxide, 1 part of stearic acid, 1-2 parts of vulcanizing agent, 10-15 parts of reinforcing agent, 0.5 parts of antioxidant, and 1-2 parts of plasticizer according to the following weight proportions. Step 2: Add natural rubber, carboxylated nitrile rubber, and chloroprene rubber to a mixer for plasticizing. Add zinc oxide and stearic acid for mixing. Add reinforcing agents and plasticizers. Discharge the rubber onto a two-roll mill, form triangular slugs, thin-pass through, sheet, and cool to obtain masterbatch. Thin-pass through the masterbatch on the two-roll mill, add modified rubber, thin-pass through, form triangular slugs, add vulcanizing agents, cut left and right, and re-mix. Fill into a mold, place in a flat vulcanizing machine for vulcanization, cool, and crush with a crusher to obtain rubber granules with high bonding strength for running tracks.

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