Stable ozone-resistant environment-friendly rubber DTPD composite anti-aging agent and preparation method thereof

Abstract

The invention relates to a stable ozone-resistant environment-friendly rubber DTPD composite anti-aging agent and a preparation method thereof, and belongs to the technical field of rubber anti-aging agents, and the preparation method comprises the following steps: combining the rubber anti-aging agent DTPD with an epoxy compound to obtain a composite material; the composite material is combined with 5-amino-2-mercapto benzimidazole, and a reinforcing material is obtained; and combining the reinforcing material with a phenolic antioxidant to finally obtain the stable ozone-resistant environment-friendly rubber DTPD composite anti-aging agent. According to the technical scheme, the anacardol glycidyl ether and the glycidyl methacrylate are mixed to form the epoxy compound, so that the migration resistance, the solvent extraction resistance and the oxidation resistance of the anti-aging agent can be better enhanced; according to the rubber DTPD composite anti-aging agent disclosed by the invention, the phenolic antioxidant formed by mixing gallic acid and pterostilbene can better improve the ozone aging resistance, solvent extraction resistance and migration resistance of the rubber anti-aging agent, the overall comprehensive performance of the rubber DTPD composite anti-aging agent is improved, and the environmental protection property is better.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber antioxidants, and in particular relates to a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant and a preparation method thereof. Background Art

[0002] In automobile tire manufacturing, the durability and aging resistance of rubber materials are key factors in ensuring safety and extending their service life. Tires are exposed to various harsh environmental conditions, such as UV rays, heat, oxygen, and ozone, which can cause rubber aging, manifesting as cracking, hardening, or loss of elasticity, thus affecting tire performance and safety. Antioxidants, as indispensable rubber additives, play a vital role in slowing the aging process and extending the service life of rubber materials. Therefore, adding appropriate antioxidants to tire rubber formulations can effectively improve tire weather resistance and extend its service life. Currently, paraphenylenediamine-based antioxidants account for the majority of the rubber antioxidant market. These antioxidants, with their excellent protective properties and relatively mature production systems, are a commonly used antioxidant type in the tire industry.

[0003] In the prior art, rubber antioxidant DTPD is the most widely used antioxidant, but it has a single function, a low molecular weight, and disadvantages such as easy volatility and migration, poor thermal stability, and inability to resist solvent extraction. It is easily volatilized by heat during use, migrates to the surface of the rubber material with increasing use time, and is easily lost by contact with solvent extraction, resulting in a significant decrease in the performance and service life of the rubber material. Due to reasons such as the migration of the rubber antioxidant to the surface and extraction by the solvent, it diffuses into the surrounding environment, causing environmental pollution and endangering people's health and safety. In addition, the ozone aging resistance of the rubber antioxidant DTPD needs to be further improved. Therefore, it is necessary to prepare a rubber DTPD composite antioxidant that not only has good thermal stability, antioxidant properties, migration resistance, solvent extraction resistance and ozone aging resistance, but also has good environmental performance. Summary of the Invention

[0004] The present invention aims to provide a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant and a preparation method thereof. The invention comprises the following steps: combining a rubber antioxidant DTPD with an epoxy compound to obtain a composite material; combining the composite material in step S1 with 5-amino-2-mercaptobenzimidazole to obtain a reinforcing material; combining the reinforcing material in step S2 with a phenolic antioxidant to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant. The prepared rubber DTPD composite antioxidant not only has good thermal stability, antioxidant properties, migration resistance, solvent extraction resistance and ozone aging resistance, but also has good environmental performance, thereby overall improving the comprehensive performance of the rubber DTPD composite antioxidant.

[0005] The technical problems to be solved by the present application are: in the prior art, rubber antioxidant DTPD is the most widely used antioxidant, but it has the disadvantages of single function, low molecular weight, easy volatilization and migration, poor thermal stability, poor solvent extraction resistance, easy volatilization under heat, migration to the surface of the rubber material with the increase of use time, easy loss due to contact with solvent extraction, etc., resulting in significant decrease in the performance and service life of the rubber material; due to the migration of the rubber antioxidant to the surface, extraction by the solvent, etc., the rubber antioxidant diffuses to the surrounding environment, causing environmental pollution and endangering the health and safety of people; in addition, the ozone aging resistance of the rubber antioxidant DTPD needs to be further improved, therefore, it is necessary to prepare a rubber DTPD composite antioxidant which not only has good thermal stability, oxidation resistance, migration resistance, solvent extraction resistance and ozone aging resistance, but also has good environmental protection.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A preparation method of a stable ozone-resistant environment-friendly rubber DTPD composite antioxidant comprises the following steps:

[0008] S1: combining rubber antioxidant DTPD with an epoxy compound to obtain a composite material;

[0009] S2: combining the composite material in step S1 with 5-amino-2-mercaptobenzimidazole to obtain a reinforced material;

[0010] S3: combining the reinforced material in step S2 with a phenolic antioxidant to finally obtain a stable ozone-resistant environment-friendly rubber DTPD composite antioxidant.

[0011] Further, step S1 is specifically:

[0012] The rubber antioxidant DTPD is mixed with the epoxy compound, a catalyst is added, and stirring is performed in an oil bath at 80-90℃ for 0.5-1.5h, then the temperature is increased to 145-155℃, and stirring is performed under a nitrogen atmosphere for 7.5-8.5h, after the reaction is completed, cooling to room temperature, dichloromethane is added, washed with saturated sodium bicarbonate solution first, then with deionized water, dichloromethane is removed by rotary evaporation, and finally vacuum drying is performed at 35-45℃ to obtain the composite material.

[0013] In the above reaction process, the rubber antioxidant DTPD has a secondary amine group, and the epoxy compound has an epoxy group, the secondary amine in the rubber antioxidant DTPD can react with the epoxy group in the epoxy compound, the rubber antioxidant DTPD is combined with the epoxy compound, and finally the composite material is obtained.

[0014] Further, the mass ratio of the rubber antioxidant DTPD to the epoxy compound is 1-1.2:0.9-1.1.

[0015] Furthermore, the epoxy composite is composed of a mixture of cardanol glycidyl ether and glycidyl methacrylate in a mass ratio of 0.8-0.9:0.6-0.7.

[0016] Furthermore, the catalyst is salicylic acid.

[0017] Furthermore, step S2 is specifically as follows:

[0018] The composite material, tetrahydrofuran and catalyst in step S1 are mixed evenly and stirred for 0.5-1h, and then 5-amino-2-mercaptobenzimidazole is added. The mixture is stirred and reacted at 45-55°C in a nitrogen atmosphere for 11-13h. After the reaction is completed, the mixture is added to ether, filtered, washed with ether, and finally dried in vacuum at 40-50°C to obtain a reinforced material.

[0019] During the above reaction process, the epoxy compound in the composite material has a carbon-carbon double bond, and the 5-amino-2-mercaptobenzimidazole has a thiol group. The carbon-carbon double bond in the composite material can react with the thiol group in the 5-amino-2-mercaptobenzimidazole, thereby combining the composite material and the 5-amino-2-mercaptobenzimidazole to finally obtain a reinforced material.

[0020] Furthermore, the mass ratio of the composite material, tetrahydrofuran and catalyst is 9.5-10.5:140-160:0.35-0.45.

[0021] Furthermore, the catalyst is triethylamine.

[0022] Furthermore, the mass of the 5-amino-2-mercaptobenzimidazole is 80% of the mass of the composite material.

[0023] Furthermore, step S3 is specifically as follows:

[0024] The reinforcing material in step S2 is added to dimethyl sulfoxide and mixed evenly to obtain component A. A phenolic antioxidant is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added and stirred for 0.5-1.5 hours to obtain component B. Component B is added to component A, and then reacted at 45-55° C. for 22-24 hours. After the reaction is completed, the mixture is filtered, washed with ethanol, and vacuum dried at 55-65° C. to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant.

[0025] During the above reaction process, the 5-amino-2-mercaptobenzimidazole in the reinforcing material has an amino group, and the phenolic antioxidant has a carboxyl group. The amino group in the reinforcing material can react and combine with the carboxyl group in the phenolic antioxidant, and the reinforcing material and the phenolic antioxidant are combined together to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant.

[0026] Furthermore, the mass ratio of the reinforcing material to dimethyl sulfoxide is 5.8-6.2:140-160.

[0027] Furthermore, the mass ratio of the phenolic antioxidant, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide is 12-13:140-160:9-10:5-6.

[0028] Furthermore, the phenolic antioxidant is composed of gallic acid and pterostilbene mixed in a mass ratio of 0.9-1.1:0.6-0.7.

[0029] Furthermore, the mass ratio of component B to component A is 3:1.

[0030] Beneficial effects of the present invention:

[0031] (1) In the technical solution of the present invention, a composite material is obtained by combining the rubber antioxidant DTPD with an epoxy composite; the epoxy composite is composed of a mixture of cardanol glycidyl ether and methacrylate glycidyl ester, and the two have a synergistic effect, wherein cardanol glycidyl ether is a renewable resource, environmentally friendly and pollution-free, and has the characteristics of low viscosity, good thermal stability, low price, large molecular weight, and plasticizing ability; methacrylate glycidyl ester has good solubility and good reactivity. The rubber antioxidant DTPD is combined with the epoxy composite, and the bonding force between the rubber antioxidant DTPD and the epoxy composite is good, which can not only increase the molecular weight of the rubber antioxidant, but also better improve the antioxidant performance and thermal stability of the rubber antioxidant, and further enhance the migration resistance and solvent extraction resistance of the antioxidant. and mechanical properties. In addition, the epoxy compound can also provide reaction sites for subsequent reactions; the composite material in step S1 is combined with 5-amino-2-mercaptobenzimidazole to obtain a reinforced material; 5-amino-2-mercaptobenzimidazole itself can be used as a heterocyclic antioxidant with good antioxidant properties, heat resistance and ozone resistance. Combining 5-amino-2-mercaptobenzimidazole with the composite material can not only improve the binding force between the two, but also enhance the thermal stability, antioxidant properties and ozone aging resistance of the rubber antioxidant. At the same time, 5-amino-2-mercaptobenzimidazole can also provide reaction sites for subsequent reactions, further enhancing the binding between the composite material and the phenolic antioxidant, effectively improving the overall thermal stability of the rubber antioxidant, and enhancing its antioxidant properties, migration resistance, solvent extraction resistance and ozone aging resistance.

[0032] (2) In the technical solution of the present invention, the reinforcing material in step S2 is combined with a phenolic antioxidant to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant; the phenolic antioxidant is composed of a mixture of gallic acid and pterostilbene, and both gallic acid and pterostilbene belong to phenolic antioxidants. The mixture of the two can play a synergistic role, which can improve the antioxidant performance and thermal stability of the rubber antioxidant, and gallic acid and pterostilbene have a good anti-ozone effect on rubber. Combining gallic acid and pterostilbene with the reinforcing material not only has good binding force, but the phenolic antioxidant can further improve the ozone aging resistance, solvent extraction resistance and migration resistance of the rubber antioxidant, and also increases the environmental protection performance of the rubber antioxidant, reduces pollution to the environment and harm to the human body, and finally the prepared stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant has good overall comprehensive performance.

[0033] (3) In the technical scheme of the present application, the rubber antioxidant DTPD is combined with an epoxy compound, then combined with 5-amino-2-mercapto benzimidazole, and then combined with a phenolic antioxidant, and finally a stable ozone-resistant environment-friendly rubber DTPD composite antioxidant is prepared. The prepared rubber DTPD composite antioxidant not only has good thermal stability, oxidation resistance, migration resistance, solvent extraction resistance and ozone aging resistance, but also has good environmental protection and good overall comprehensive performance. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] The specific parameters of the raw materials used in the present application are as follows:

[0036] The rubber antioxidant DTPD, CAS number: 27417-40-9, is provided by Wuhan Lingfan Technology Co., Ltd., cashew phenol glycidyl ether, CAS number: 171263-25-5, product number: C992604, provided by Shanghai Macklin Biochemical Technology Co., Ltd.; glycidyl methacrylate, CAS number: 106-91-2, product number: G810426, provided by Shanghai Macklin Biochemical Technology Co., Ltd.; 5-amino-2-mercapto benzimidazole, CAS number: 2818-66-8, product number: A151156, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; gallic acid, CAS number: 149-91-7, product number: G823638, provided by Shanghai Macklin Biochemical Technology Co., Ltd.; pterostilbene, CAS number: 537-42-8, product number: P108000, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0037] Example 1

[0038] The preparation method of the stable ozone-resistant environment-friendly rubber DTPD composite antioxidant comprises the following steps:

[0039] S1: According to the mass ratio of rubber antioxidant DTPD and epoxy compound of 1:0.9, the rubber antioxidant DTPD and epoxy compound were mixed, and salicylic acid (the mass of salicylic acid is 1% of the mass of rubber antioxidant DTPD) was added, and stirred in an 80°C oil bath for 0.5h, then the temperature was raised to 145°C, and stirred under a nitrogen atmosphere for 7.5h. After the reaction was completed, it was cooled to room temperature, and dichloromethane (the mass of dichloromethane is 15 times the mass of rubber antioxidant DTPD) was added, and 10 The epoxy composite was washed three times with wt% saturated sodium bicarbonate solution (the mass of each saturated sodium bicarbonate solution was 10 times the mass of the rubber antioxidant DTPD), and then washed three times with deionized water (the mass of each deionized water was 12 times the mass of the rubber antioxidant DTPD), and dichloromethane was removed by rotary evaporation at 30°C, and finally vacuum dried at 35°C for 12 hours to obtain a composite material, wherein the epoxy composite was composed of cardanol glycidyl ether and glycidyl methacrylate mixed in a mass ratio of 0.8:0.6;

[0040] S2: According to the mass ratio of the composite material, tetrahydrofuran and triethylamine being 9.5:140:0.35, the composite material, tetrahydrofuran and triethylamine in step S1 were uniformly mixed and stirred at a speed of 700 rpm for 1 hour, and then 5-amino-2-mercaptobenzimidazole (the mass of 5-amino-2-mercaptobenzimidazole was 80% of the mass of the composite material) was added, and stirred for 11 hours at 45°C under a nitrogen atmosphere. After the reaction was completed, ether was added (the mass of ether was 40% of the mass of tetrahydrofuran), filtered, washed with ether three times (the mass of ether each time was 10% of the mass of tetrahydrofuran), and finally vacuum dried at 40°C for 24 hours to obtain a reinforced material;

[0041] S3: According to the mass ratio of reinforcing material to dimethyl sulfoxide of 5.8:140, the reinforcing material in step S2 is added to dimethyl sulfoxide, and the mixture is evenly mixed to obtain component A. According to the mass ratio of phenolic antioxidant, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide of 12:140:9:5, the phenolic antioxidant is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added. and stirred for 0.5h to obtain component B. According to the mass ratio of component B to component A of 3:1, component B was added to component A, and then reacted at 45°C for 22h. After the reaction, it was filtered and washed with ethanol 3 times (the mass of each ethanol was 3 times the mass of N-hydroxysuccinimide), and vacuum dried at 55°C for 24h to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant, wherein the phenolic antioxidant was composed of gallic acid and pterostilbene mixed in a mass ratio of 0.9:0.6.

[0042] Example 2

[0043] The preparation method of the stable ozone-resistant environmental-friendly rubber DTPD composite antioxidant comprises the following steps:

[0044] S1: according to the mass ratio of rubber antioxidant DTPD to epoxy compound is 1.1:1, the rubber antioxidant DTPD is mixed with the epoxy compound, then the salicylic acid (the mass of salicylic acid is 1% of the mass of rubber antioxidant DTPD) is added, the mixture is stirred in the oil bath at 85℃ for 1h, then the temperature is increased to 150℃, and the mixture is stirred under the nitrogen atmosphere for 8h, after the reaction is completed, the mixture is cooled to room temperature, then dichloromethane (the mass of dichloromethane is 15 times of the mass of rubber antioxidant DTPD) is added, the mixture is washed with 10wt% saturated sodium bicarbonate solution for 3 times (the mass of saturated sodium bicarbonate solution is 10 times of the mass of rubber antioxidant DTPD), then the mixture is washed with deionized water for 3 times (the mass of deionized water is 12 times of the mass of rubber antioxidant DTPD), the dichloromethane is removed by rotary evaporation at 35℃, finally the mixture is vacuum dried at 40℃ for 12h, to obtain the composite material, wherein the epoxy compound is composed of cardanol glycidyl ether and glycidyl methacrylate according to the mass ratio of 0.85:0.65;

[0045] S2: according to the mass ratio of the composite material, tetrahydrofuran and triethylamine is 10:150:0.4, the composite material, tetrahydrofuran and triethylamine in step S1 are mixed uniformly, and stirred at the speed of 800rpm for 0.7h, then 5-amino-2-mercaptobenzimidazole (the mass of 5-amino-2-mercaptobenzimidazole is 80% of the mass of the composite material) is added, the mixture is stirred under the nitrogen atmosphere and at 50℃ for 12h, after the reaction is completed, the mixture is added into diethyl ether (the mass of diethyl ether is 40% of the mass of tetrahydrofuran), filtered, washed with diethyl ether for 3 times (the mass of diethyl ether is 10% of the mass of tetrahydrofuran), finally the mixture is vacuum dried at 45℃ for 24h, to obtain the reinforced material;

[0046] S3: According to the mass ratio of reinforcing material and dimethyl sulfoxide of 6:150, the reinforcing material in step S2 is added to dimethyl sulfoxide, and the mixture is evenly mixed to obtain component A. According to the mass ratio of phenolic antioxidant, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide of 12.5:150:9.5:5.5, the phenolic antioxidant is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added. Imide, and stirred for 1 hour to obtain component B, according to the mass ratio of component B to component A of 3:1, component B is added to component A, and then reacted at 50°C for 23 hours. After the reaction is completed, it is filtered and washed with ethanol 3 times (the mass of each ethanol is 3 times the mass of N-hydroxysuccinimide), and vacuum dried at 60°C for 24 hours to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant, wherein the phenolic antioxidant is composed of gallic acid and pterostilbene mixed in a mass ratio of 1:0.65.

[0047] Example 3

[0048] The preparation method of the stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant comprises the following steps:

[0049] S1: According to the mass ratio of rubber antioxidant DTPD and epoxy compound of 1.2:1.1, the rubber antioxidant DTPD and epoxy compound were mixed, and salicylic acid (the mass of salicylic acid was 1% of the mass of rubber antioxidant DTPD) was added. The mixture was stirred in an oil bath at 90°C for 1.5h, and then the temperature was raised to 155°C and stirred under a nitrogen atmosphere for 8.5h. After the reaction was completed, the mixture was cooled to room temperature and dichloromethane (the mass of dichloromethane was 15 times the mass of rubber antioxidant DTPD) was added. The mixture was first stirred with 1% water. The obtained composite material was washed three times with 0wt% saturated sodium bicarbonate solution (the mass of each saturated sodium bicarbonate solution was 10 times the mass of the rubber antioxidant DTPD), and then washed three times with deionized water (the mass of each deionized water was 12 times the mass of the rubber antioxidant DTPD), and dichloromethane was removed by rotary evaporation at 40°C. Finally, the composite material was vacuum dried at 45°C for 12 hours to obtain a composite material, wherein the epoxy composite was composed of cardanol glycidyl ether and glycidyl methacrylate mixed in a mass ratio of 0.9:0.7;

[0050] S2: According to the mass ratio of the composite material, tetrahydrofuran and triethylamine being 10.5:160:0.45, the composite material, tetrahydrofuran and triethylamine in step S1 were mixed uniformly and stirred at a speed of 900 rpm for 0.5 h, and then 5-amino-2-mercaptobenzimidazole was added (the mass of 5-amino-2-mercaptobenzimidazole was 80% of the mass of the composite material), and the mixture was stirred for 13 h under a nitrogen atmosphere at 55°C. After the reaction was completed, the mixture was added to diethyl ether (the mass of diethyl ether was 40% of the mass of tetrahydrofuran), filtered, washed with diethyl ether three times (the mass of diethyl ether each time was 10% of the mass of tetrahydrofuran), and finally dried in vacuo at 50°C for 24 h to obtain a reinforced material;

[0051] S3: According to the mass ratio of reinforcing material and dimethyl sulfoxide of 6.2:160, the reinforcing material in step S2 is added to dimethyl sulfoxide, and the mixture is evenly mixed to obtain component A. According to the mass ratio of phenolic antioxidant, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide of 13:160:10:6, the phenolic antioxidant is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added. , and stirred for 1.5 hours to obtain component B. According to the mass ratio of component B to component A of 3:1, component B was added to component A, and then reacted at 55°C for 24 hours. After the reaction, it was filtered and washed with ethanol three times (the mass of each ethanol was 3 times the mass of N-hydroxysuccinimide), and vacuum dried at 65°C for 24 hours to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant, wherein the phenolic antioxidant was composed of gallic acid and pterostilbene mixed in a mass ratio of 1.1:0.7.

[0052] Comparative Example 1

[0053] The difference between this comparative example and Example 3 is that when preparing the stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant, in step S1, the epoxy compound is replaced with cardanol glycidyl ether, and the remaining steps and raw materials are synchronized with Example 3;

[0054] S1: According to the mass ratio of rubber antioxidant DTPD and cardanol glycidyl ether being 1.2:1.1, the rubber antioxidant DTPD and cardanol glycidyl ether were mixed, and salicylic acid was added (the mass of salicylic acid was 1% of the mass of the rubber antioxidant DTPD). The mixture was stirred in an oil bath at 90°C for 1.5h, and then the temperature was raised to 155°C and stirred for 8.5h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature and dichloromethane was added (the mass of dichloromethane was 15 times the mass of the rubber antioxidant DTPD). The mixture was first washed three times with 10wt% saturated sodium bicarbonate solution (the mass of each saturated sodium bicarbonate solution was 10 times the mass of the rubber antioxidant DTPD), and then washed three times with deionized water (the mass of each deionized water was 12 times the mass of the rubber antioxidant DTPD). The dichloromethane was removed by rotary evaporation at 40°C, and finally vacuum dried at 45°C for 12h to obtain a composite material.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 3 is that when preparing the stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant, in step S1, the epoxy compound is replaced by glycidyl methacrylate, and the remaining steps and raw materials are the same as in Example 3;

[0057] S1: According to the mass ratio of rubber antioxidant DTPD and glycidyl methacrylate of 1.2:1.1, the rubber antioxidant DTPD and glycidyl methacrylate were mixed, and salicylic acid was added (the mass of salicylic acid was 1% of the mass of the rubber antioxidant DTPD). The mixture was stirred in an oil bath at 90°C for 1.5 hours, and then the temperature was raised to 155°C and stirred for 8.5 hours under a nitrogen atmosphere. After the reaction was completed, it was cooled to room temperature and dichloromethane was added (the mass of dichloromethane was 15 times the mass of the rubber antioxidant DTPD). The mixture was first washed three times with 10wt% saturated sodium bicarbonate solution (the mass of each saturated sodium bicarbonate solution was 10 times the mass of the rubber antioxidant DTPD), and then washed three times with deionized water (the mass of each deionized water was 12 times the mass of the rubber antioxidant DTPD). The dichloromethane was removed by rotary evaporation at 40°C, and finally vacuum dried at 45°C for 12 hours to obtain a composite material.

[0058] Comparative Example 3

[0059] The difference between this comparative example and Example 3 is that when preparing the stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant, in step S2, 5-amino-2-mercaptobenzimidazole is replaced by 2-mercaptobenzimidazole, and the remaining steps and raw materials are the same as in Example 3;

[0060] S2: According to the mass ratio of the composite material, tetrahydrofuran and triethylamine is 10.5:160:0.45, the composite material, tetrahydrofuran and triethylamine in step S1 are mixed uniformly, and stirred at a speed of 900 rpm for 0.5 h, then 2-mercaptobenzimidazole (2-mercaptobenzimidazole mass is 80% of the mass of the composite material) is added, stirred and reacted under a nitrogen atmosphere at 55°C for 13 h, after the reaction is completed, it is added into diethyl ether (diethyl ether mass is 40% of the mass of tetrahydrofuran), filtered, washed with diethyl ether for 3 times (each time diethyl ether mass is 10% of the mass of tetrahydrofuran), and finally vacuum dried at 50°C for 24 h to obtain the reinforcing material.

[0061] Comparative Example 4

[0062] The difference between this comparative example and Example 3 is that, when preparing the stable ozone-resistant environment-friendly rubber DTPD composite antioxidant, the composite material in step S1 is directly combined with the phenolic antioxidant, and the original step S2 is deleted, and the remaining steps and raw materials are implemented synchronously with Example 3.

[0063] S1: According to the mass ratio of the rubber antioxidant DTPD and the epoxy compound is 1.2:1.1, the rubber antioxidant DTPD and the epoxy compound are mixed, then salicylic acid (salicylic acid mass is 1% of the mass of the rubber antioxidant DTPD) is added, stirred in an oil bath at 90°C for 1.5 h, then the temperature is increased to 155°C, and stirred and reacted under a nitrogen atmosphere for 8.5 h, after the reaction is completed, cooled to room temperature, dichloromethane (dichloromethane mass is 15 times of the mass of the rubber antioxidant DTPD) is added, washed with 10 wt% saturated sodium bicarbonate solution for 3 times (each time saturated sodium bicarbonate solution mass is 10 times of the mass of the rubber antioxidant DTPD), then washed with deionized water for 3 times (each time deionized water mass is 12 times of the mass of the rubber antioxidant DTPD), dichloromethane is removed by rotary evaporation at 40°C, and finally vacuum dried at 45°C for 12 h to obtain the composite material, wherein the epoxy compound is composed of cardanol glycidyl ether and glycidyl methacrylate according to a mass ratio of 0.9:0.7;

[0064] S2: According to the mass ratio of composite material and dimethyl sulfoxide of 6.2:160, the composite material in step S1 is added to dimethyl sulfoxide, and the mixture is evenly mixed to obtain component A. According to the mass ratio of phenolic antioxidant, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide of 13:160:10:6, the phenolic antioxidant is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added. , and stirred for 1.5 hours to obtain component B. According to the mass ratio of component B to component A of 3:1, component B was added to component A, and then reacted at 55°C for 24 hours. After the reaction, it was filtered and washed with ethanol three times (the mass of each ethanol was 3 times the mass of N-hydroxysuccinimide), and vacuum dried at 65°C for 24 hours to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant, wherein the phenolic antioxidant was composed of gallic acid and pterostilbene mixed in a mass ratio of 1.1:0.7.

[0065] Comparative Example 5

[0066] The difference between this comparative example and Example 3 is that when preparing the stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant, in step S3, the phenolic antioxidant and other qualities are replaced by gallic acid, and the remaining steps and raw materials are synchronized with Example 3;

[0067] S3: According to the mass ratio of reinforcing material and dimethyl sulfoxide being 6.2:160, the reinforcing material in step S2 is added to dimethyl sulfoxide, and the mixture is evenly mixed to obtain component A. According to the mass ratio of gallic acid, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide being 13:160:10:6, gallic acid is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is stirred for 1.5 hours to obtain component B. According to the mass ratio of component B to component A being 3:1, component B is added to component A, and then the mixture is reacted at 55°C for 24 hours. After the reaction is completed, the mixture is filtered, washed three times with ethanol (the mass of ethanol each time is 3 times the mass of N-hydroxysuccinimide), and vacuum dried at 65°C for 24 hours to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant.

[0068] Comparative Example 6

[0069] The difference between this comparative example and Example 3 is that when preparing the stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant, in step S3, the phenolic antioxidant and other qualities are replaced with pterostilbene, and the remaining steps and raw materials are synchronized with Example 3;

[0070] S3: According to the mass ratio of reinforcing material and dimethyl sulfoxide of 6.2:160, the reinforcing material in step S2 is added to dimethyl sulfoxide, and the mixture is evenly mixed to obtain component A. According to the mass ratio of pterostilbene, dimethyl sulfoxide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide of 13:160:10:6, pterostilbene is added to dimethyl sulfoxide, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is stirred for 1.5 hours to obtain component B. According to the mass ratio of component B to component A of 3:1, component B is added to component A, and then reacted at 55°C for 24 hours. After the reaction, it is filtered, washed with ethanol three times (the mass of ethanol each time is 3 times the mass of N-hydroxysuccinimide), and vacuum dried at 65°C for 24 hours to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant.

[0071] The stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant prepared in Examples 1-3 and Comparative Examples 1-6 was used to prepare nitrile rubber, and then the antioxidant performance, solvent extraction resistance and ozone aging resistance were tested.

[0072] The nitrile rubber was prepared by the following steps: after 100 parts of nitrile rubber were thinned on an open mill for 8 times, 2 parts of stearic acid, 5 parts of zinc oxide, and 30 parts of white carbon black were added, and the stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant prepared in Examples 1-3 and Comparative Examples 1-6 were added respectively, and mixed evenly, and then 2 parts of accelerator NS, 0.5 parts of accelerator DM and 2 parts of sulfur were added, mixed evenly and then sheeted to obtain a rubber mix; the rubber mix was left for 24 hours and then sheeted on a flat vulcanizing press, and cured for a positive vulcanization time T C90 The vulcanization was carried out at a vulcanization temperature of 160°C. The vulcanized nitrile rubber samples were kept at room temperature for 24 hours for performance testing.

[0073] Oxidation resistance test: The heat-oxidation aging resistance test was conducted according to GB / T 3512-2001. The aging temperature was 100°C and the aging time was 48 h. The aging coefficient (k) was used as an evaluation index for the heat-oxidation aging resistance. The tensile product f = tensile strength × elongation at break. The aging coefficient (k) was determined by the tensile product after aging and the tensile product before aging. The aging coefficient (k) was calculated according to the formula: k = f1 / f2, where f1 represents the tensile product of the sample before aging and f2 represents the tensile product of the sample after aging. A larger k value indicates better aging resistance. The test results are shown in Table 1 below.

[0074] Solvent extraction resistance test: Extract and soak in methanol for 72 hours, then perform thermal oxygen accelerated aging (100℃×48h). The tensile aging coefficient retention rate (k r) characterizes the quality of solvent extraction resistance, and the aging coefficient retention rate (k r ):k r =k / k0, k represents the aging coefficient after 72h of methanol extraction and then 48h of accelerated aging at 100℃, k0 represents the aging coefficient after 48h of accelerated aging at 100℃ without methanol extraction, k r The larger the value, the better the solvent extraction resistance. The test results are shown in Table 1 below.

[0075] Ozone aging resistance test:

[0076] (1) According to the surface cracking method of rubber aging test in GB / T 11206-2019, the static ozone aging resistance performance test of the vulcanized specimens was carried out in an ozone aging test chamber. The experimental conditions were: static ozone concentration 50 pphm, temperature 40°C, and stretching 20%. The test results are shown in Table 2 below. The meanings of 1c, 2c, 3c, and 4c in Table 2 can be found in the standard GB / T 11206-2019.

[0077] (2) According to GB / T 13642-2015 Dynamic tensile test for ozone cracking resistance of vulcanized rubber or thermoplastic rubber, the dynamic ozone aging resistance performance test of the vulcanized specimens was carried out in an ozone aging test chamber. The experimental conditions were: dynamic ozone concentration 50 pphm, temperature 40°C, stretching 20%, frequency 0.5 Hz. The test results are shown in Table 2 below. The meanings of 1c, 2c, 3c, and 4c in Table 2 can be found in standard GB / T 11206-2019.

[0078] Table 1 Test results of antioxidant performance and solvent extraction resistance

[0079] project Thermal oxidative aging (100℃×48h) <![CDATA[老化系数保持率k r (%)]]> Example 1 0.92 92.2 Example 2 0.93 92.4 Example 3 0.91 91.9 Comparative Example 1 0.80 86.7 Comparative Example 2 0.77 86.2 Comparative Example 3 0.72 85.6 Comparative Example 4 0.65 84.9 Comparative Example 5 0.79 86.3 Comparative Example 6 0.75 85.8

[0080] Table 2 Test results of static ozone aging resistance and dynamic ozone aging resistance

[0081]

[0082] As can be seen from the data in Tables 1 and 2 above, it can be seen from the comparison of Comparative Examples 1-2 and Example 3 that the mass of the epoxy compound is replaced with cardanol glycidyl ether or glycidyl methacrylate, and finally a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant is prepared. The test results are poorer than those in Example 3, indicating that the epoxy compound composed of a mixture of cardanol glycidyl ether and glycidyl methacrylate has a synergistic effect and good antioxidant properties. Combining the epoxy compound with the rubber antioxidant DTPD can not only increase the molecular weight of the rubber antioxidant, but also further improve the antioxidant properties, migration resistance, solvent extraction resistance and ozone aging resistance of the rubber antioxidant.

[0083] By comparing Comparative Examples 3-4 with Example 3, it can be seen that the 5-amino-2-mercaptobenzimidazole in step S2 is replaced with 2-mercaptobenzimidazole, or the composite material in step S1 is directly combined with a phenolic antioxidant to prepare a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant. The test results are worse than those of Example 3, indicating that combining 5-amino-2-mercaptobenzimidazole with the composite material can not only enhance the binding force between the two, but also provide reaction sites for subsequent reactions, thereby further improving the antioxidant performance, solvent extraction resistance, and ozone aging resistance of the rubber antioxidant;

[0084] By comparing Comparative Examples 5-6 with Example 3, it can be seen that the phenolic antioxidant is replaced by gallic acid or pterostilbene in mass, and finally a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant is prepared. The test results are worse than those of Example 3, indicating that the phenolic antioxidant composed of a mixture of gallic acid and pterostilbene has a synergistic effect and has good anti-ozone performance. Combining phenolic antioxidants with reinforcing materials can further improve the antioxidant performance, migration resistance, solvent extraction resistance and ozone aging resistance of the rubber antioxidant.

[0085] It can be seen from the data in Table 1 and Table 2 above that the stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant prepared in Example 1-3 is compared with the stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant prepared in Comparative Examples 1-6. By combining the rubber antioxidant DTPD with an epoxy complex, and then combining it with 5-amino-2-mercaptobenzimidazole, and then combining it with a phenolic antioxidant, a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant is finally prepared, which meets the test performance requirements, while the stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant prepared in Comparative Examples 1-6 does not meet the performance requirements. The standard indicates that the stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant prepared by the present invention not only has good thermal stability, antioxidant properties, migration resistance, solvent extraction resistance and ozone aging resistance, but also has good environmental protection and good overall comprehensive performance.

[0086] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0087] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant, characterized in that: The following steps are involved: S1: combining the rubber antioxidant DTPD with the epoxy compound to obtain a composite material; S2: combining the composite material in step S1 with 5-amino-2-mercaptobenzimidazole to obtain a reinforced material; S3: combining the reinforcing material in step S2 with a phenolic antioxidant to obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant.

2. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 1, characterized in that: Step S1 is specifically as follows: The rubber antioxidant DTPD is mixed with the epoxy complex, and then a catalyst is added. The mixture is stirred in an oil bath at 80-90°C for 0.5-1.5 hours, and then the temperature is increased to 145-155°C and stirred for reaction under a nitrogen atmosphere for 7.5-8.5 hours. After the reaction is completed, the mixture is cooled to room temperature and then dichloromethane is added. The mixture is first washed with a saturated sodium bicarbonate solution and then with deionized water. The dichloromethane is removed by rotary evaporation and finally vacuum dried at 35-45°C to obtain a composite material.

3. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 2, characterized in that: The mass ratio of the rubber antioxidant DTPD to the epoxy compound is 1-1.2:0.9-1.

1.

4. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 2, characterized in that: The epoxy compound is formed by mixing cardanol glycidyl ether and glycidyl methacrylate in a mass ratio of 0.8-0.9:0.6-0.

7.

5. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 2, characterized in that: The catalyst is salicylic acid.

6. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 1, characterized in that: Step S2 is specifically as follows: The composite material, tetrahydrofuran and catalyst in step S1 are mixed evenly and stirred for 0.5-1h, and then 5-amino-2-mercaptobenzimidazole is added. The mixture is stirred and reacted at 45-55°C in a nitrogen atmosphere for 11-13h. After the reaction is completed, the mixture is added to ether, filtered, washed with ether, and finally dried in vacuum at 40-50°C to obtain a reinforced material.

7. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 6, characterized in that: The mass ratio of the composite material, tetrahydrofuran and catalyst is 9.5-10.5:140-160:0.35-0.

45.

8. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 1, characterized in that: Step S3 is specifically as follows: The reinforcing material in step S2 is added to dimethyl sulfoxide and mixed evenly to obtain component A. A phenolic antioxidant is added to dimethyl sulfoxide, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added and stirred for 0.5-1.5 hours to obtain component B. Component B is added to component A, and then reacted at 45-55° C. for 22-24 hours. After the reaction is completed, the mixture is filtered, washed with ethanol, and vacuum dried at 55-65° C. to finally obtain a stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant.

9. The method for preparing a stable ozone-resistant environmentally friendly rubber DTPD composite antioxidant according to claim 8, characterized in that: The phenolic antioxidant is composed of gallic acid and pterostilbene mixed in a mass ratio of 0.9-1.1:0.6-0.

7.

10. A stable ozone-resistant and environmentally friendly rubber DTPD composite antioxidant prepared by the preparation method according to any one of claims 1 to 9.

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