Multi-effect anti-aging agent and preparation method thereof

Abstract

The invention relates to a multi-effect anti-aging agent and a preparation method thereof, and belongs to the technical field of anti-aging agents. The benzophenone structure group contained in the anti-aging agent has an ultraviolet light absorption function; and a p-phenylenediamine structure unit contained in the material has a function of eliminating active free radicals. 2, 3, 4-trihydroxybenzophenone, 4-formylphenylboronic acid, p-aminodiphenylamine and a monomer containing phosphorus-hydrogen bonds are used as raw materials, and the anti-aging agent is prepared through a dehydration reaction between a boric acid group and a catechol group, a Schiff base reaction between an aldehyde group and an amino group and an addition reaction between the phosphorus-hydrogen bonds and carbon-nitrogen double bonds through molecular design. The anti-aging agent has an ultraviolet absorption function and a thermo-oxidative aging resistance function, has good compatibility with common non-polar rubber, and can effectively improve the anti-aging performance of a polymer product.

Description

TECHNICAL FIELD

[0001] The present application relates to a multi-effect antioxidant and a preparation method thereof, and belongs to the technical field of antioxidants. BACKGROUND

[0002] Traditional plastics and rubber materials are mostly non-polar rubbers, mainly composed of carbon, hydrogen and other elements. In particular, rubber materials contain a large number of carbon-carbon double bonds in the high molecular chain unit, which are highly active and easily cause rubber materials to undergo photoaging and thermal-oxidative aging reactions. The rubber widely used in industry includes natural rubber, styrene-butadiene rubber, cis-butadiene rubber and nitrile-butadiene rubber, etc., all of which contain a large number of carbon-carbon double bonds in their structures. Rubber aging is the main cause of performance degradation of rubber products and loss of product functionality, which not only brings great economic burden to the users of rubber products, but also brings great burden to the environment due to the non-degradability of rubber products.

[0003] The traditional strategy to solve the aging problem of rubber products is to add anti-aging agents, which has low impact on the rubber processing and production process and good economic performance, so such anti-aging agents have been well applied in the market. Anti-aging agents can be divided into light stabilizers, thermal-oxidative aging inhibitors, etc. according to their functions. Among them, ultraviolet light absorbers are widely used in outdoor rubber materials as processing aids, mainly including o-hydroxybenzophenone, salicylate, benzotriazole, triazine, etc. Anti-thermal-oxidative aging agents mainly include the following types: (1) amine anti-aging agents, common products include 6PPD, RD, 4010NA, etc. This type of anti-aging agent mainly uses the secondary amino group in the p-phenylamine structure to absorb active free radicals generated during the aging process of rubber, converting them into low-activity free radicals, thereby slowing down the aging reaction; (2) phenolic anti-aging agents, usually hindered phenolic anti-aging agents, common products include antioxidant 2246, antioxidant BHT, antioxidant SP, etc.; (3) heterocyclic anti-aging agents, common varieties include 2-mercaptobenzimidazole, 2-mercaptobenzimidazole salt (antioxidant MBZ), etc.; (4) phosphite anti-aging agents, main varieties include antioxidant 168, antioxidant TNP, etc.

[0004] Many rubber products are used in open outdoor environment, and the aging of rubber needs to consider both light aging and thermal-oxidative aging, so it is often necessary to add multiple types of anti-aging agents. The main mechanism of action of anti-aging agents in rubber products is to destroy the key unit reactions of light aging and thermal-oxidative aging reactions. Light stabilizers can be divided into ultraviolet light screening agents, free radical scavengers and ultraviolet light absorbers according to their functions. The mechanism of action of ultraviolet light absorbers is to selectively absorb ultraviolet light, and to minimize or eliminate free radicals initiated by ultraviolet light in sunlight. Thermal-oxidative anti-aging agents are divided into free radical scavenging type anti-aging agents and peroxide decomposing type anti-aging agents. Amine, phenolic and heterocyclic anti-aging agents mainly scavenge active free radicals, while phosphite anti-aging agents are hydrogen peroxide decomposing type anti-aging agents. Amine anti-aging agents can effectively scavenge active free radicals, and their research is relatively mature, the market varieties are the most complete, and the price is relatively low. For outdoor rubber products, in order to prolong the service life of rubber products, it is necessary to add multiple types of anti-aging agents. However, due to the low molecular weight of traditional ultraviolet light absorbers and amine anti-aging agents, the interaction between the two and the rubber matrix is weak, and they are easy to migrate out of the rubber product matrix, causing the anti-aging performance of the rubber product to rapidly decrease with time. In addition, some amine anti-aging agents have poor compatibility with non-polar rubbers, resulting in a decrease in the mechanical properties of the material. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a multi-effect anti-aging agent and a preparation method thereof. The anti-aging agent has ultraviolet light absorption function, thermal-oxidative aging resistance, good compatibility with rubber materials, can maintain the mechanical properties of the rubber material, and has excellent anti-aging performance.

[0006] To achieve the above purpose, the technical scheme of the present application is as follows.

[0007] A preparation method of a multi-effect anti-aging agent, the method steps comprising: S1, 2, 3, 4-trihydroxybenzophenone and 4-formylphenylboronic acid are added to a solvent, and an excess of a dehydrating agent is added at the same time, a dehydration reaction occurs between the boronic acid group and the o-diphenol group to obtain a mixture containing intermediate product 1; S2, p-aminodiphenylamine is added to the mixture containing intermediate product 1, and an imination reaction occurs between the aldehyde group and the amino group to obtain a mixture containing intermediate product 2; S3, a monomer containing a phosphorus-hydrogen bond is added to the mixture containing intermediate product 2, and an addition reaction occurs between the phosphorus-hydrogen bond and the imine bond to obtain a mixture 3 containing an anti-aging agent; S4, the mixture 3 containing the anti-aging agent is filtered, and the solvent is removed by rotary evaporation to obtain a multi-effect anti-aging agent.

[0008] Preferably, in step S1, the solvent is N, N-dimethylformamide.

[0009] Preferably, in step S1, the molar ratio of the 2,3,4-trihydroxybenzophenone to the 4-formylphenylboronic acid is 1:1.

[0010] Preferably, in step S1, the dehydrating agent is one or more of magnesium sulfate, calcium sulfate and calcium chloride.

[0011] Preferably, in step S1, the reaction temperature is 80-100℃ and the reaction time is 10-24h.

[0012] Preferably, in step S2, the molar ratio of the p-aminodiphenylamine to the 4-formylphenylboronic acid of step S1 is 1:1.

[0013] Preferably, in step S2, the reaction temperature is 40-80℃ and the reaction time is 12-36h.

[0014] Preferably, in step S3, the phosphorus-hydrogen bond-containing monomer has the structural formula , wherein R is ethyl, propyl, butyl or a benzene ring. More preferably, the phosphorus-hydrogen bond-containing monomer is diethyl phosphite.

[0015] Preferably, in step S3, the molar ratio of the phosphorus-hydrogen bond-containing monomer to the 4-formylphenylboronic acid of step S1 is 1-1.5:1.

[0016] Preferably, in step S3, the reaction temperature is 40-60℃ and the reaction time is 24-48h.

[0017] A multi-effect antioxidant prepared by the above method, the antioxidant having the structural formula ; wherein R is an alkyl group or an aryl group.

[0018] Preferably, R is ethyl, propyl, butyl or a benzene ring.

[0019] Use of the multi-effect antioxidant of the present application as an antioxidant for rubber products.

[0020] Advantages The present application provides a multi-effect antioxidant, which contains a benzophenone structure group having ultraviolet light absorption function, and a p-phenylenediamine structure unit having active free radical elimination function, so that the antioxidant has both light aging protection and thermal oxygen aging protection functions. The molecular structure of the antioxidant is stable, which can effectively improve the comprehensive performance of rubber products.

[0021] The application provides a preparation method of a multi-effect antioxidant, using 2,3,4-trihydroxybenzophenone, 4-formylphenylboronic acid, p-aminodiphenylamine and a monomer containing a phosphorus-hydrogen bond as raw materials, through dehydration reaction of a boronic acid group and a catechol group, Schiff base reaction of an aldehyde group and an amino group and addition reaction of a phosphorus-hydrogen bond and a carbon-nitrogen double bond, a multi-functional antioxidant with low polarity is prepared. The multi-effect antioxidant has good compatibility with most non-polar rubbers, and the prepared antioxidant has a large molecular weight, which effectively avoids migration and precipitation of the antioxidant in rubber products.

[0022] The preparation method of the multi-effect antioxidant is convenient and easy to implement, the prepared antioxidant has excellent functions of preventing light aging and thermal oxygen aging, in addition, the antioxidant contains phosphorus elements and has certain flame retardation, and therefore has wide application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a synthesis reaction principle diagram of the multi-effect antioxidant in the embodiment of the application. DETAILED DESCRIPTION

[0024] The application will be further described in detail below in combination with specific embodiments.

[0025] As shown in the figure, a preparation method of a multi-effect antioxidant, the method steps include: Figure 1 S1, 2,3,4-trihydroxybenzophenone and 4-formylphenylboronic acid are added to a solvent, and a dehydrating agent is added at the same time, dehydration reaction of a boronic acid group and a catechol group is carried out to obtain a mixture containing intermediate product 1; S2, p-aminodiphenylamine is added to the mixture containing intermediate product 1, imidization reaction of an aldehyde group and an amino group is carried out to obtain a mixture containing intermediate product 2; S3, a monomer containing a phosphorus-hydrogen bond is added to the mixture containing intermediate product 2, addition reaction of a phosphorus-hydrogen bond and an imine bond is carried out to obtain a mixture 3 containing an antioxidant; S4, the mixture 3 containing the antioxidant is filtered, and the solvent is removed by rotary evaporation to obtain a multi-effect antioxidant. The reagents used in the following embodiments are all commercially available products, except for special instructions.

[0026] Example 1

[0027] The preparation method of the multi-effect antioxidant is as follows: The preparation method of the multi-effect antioxidant is as follows: (1) 4.6 g of 2,3,4-trihydroxybenzophenone, 3.0 g of 4-formylphenylboronic acid and 500 ml of N,N-dimethylformamide are added to a 1000 ml round bottom flask, while adding 12 g of anhydrous magnesium sulfate dehydrating agent, and the nitrogen environment is maintained in the round bottom flask, the reaction temperature is controlled at 80°C, and the reaction time is 24 h to obtain a mixture 1; (2) 3.68 g of p-aminodiphenylamine is added to the above mixture 1, the reaction temperature is controlled at 40°C, and the reaction time is 36 h to obtain a mixture 2; (3) 2.72 g of diethyl phosphite is added to the above mixture 2, the reaction temperature is controlled at 40°C, and the reaction time is continuously reacted for 48 h to obtain an antioxidant mixture 3; (4) Finally, the above mixture is filtered, and then the solvent in the solution is removed by rotary evaporation to obtain the multi-effect antioxidant.

[0028] Example 2 The preparation method of the multi-effect antioxidant is as follows: (1) 4.6 g of 2,3,4-trihydroxybenzophenone, 3.0 g of 4-formylphenylboronic acid and 500 ml of N,N-dimethylformamide are added to a 1000 ml round bottom flask, while adding 10 g of anhydrous magnesium sulfate dehydrating agent, and the nitrogen environment is maintained in the round bottom flask, the reaction temperature is controlled at 100°C, and the reaction time is 10 h to obtain a mixture 1; (2) 3.68 g of p-aminodiphenylamine is added to the above mixture 1, the reaction temperature is controlled at 80°C, and the reaction time is 12 h to obtain a mixture 2; (3) 3.4 g of diethyl phosphite is added to the above mixture 2, the reaction temperature is controlled at 60°C, and the reaction time is continuously reacted for 60 h to obtain an antioxidant mixture 3; (4) Finally, the above mixture is filtered, and then the solvent in the solution is removed by rotary evaporation to obtain the multi-effect antioxidant.

[0029] Example 3 The preparation method of the multi-effect antioxidant is as follows: (1) 4.6 g of 2,3,4-trihydroxybenzophenone, 3.0 g of 4-formylphenylboronic acid and 500 ml of N,N-dimethylformamide are added to a 1000 ml round bottom flask, while adding 12 g of anhydrous calcium sulfate dehydrating agent, and the nitrogen environment is maintained in the round bottom flask, the reaction temperature is controlled at 90°C, and the reaction time is 24 h to obtain a mixture 1; (2) 3.68 g of p-aminodiphenylamine is added to the above mixture 1, the reaction temperature is controlled at 60°C, and the reaction time is 28 h to obtain a mixture 2; (3) To the mixture 2, add 4.08 g diethyl phosphite, control the reaction temperature at 50 °C, continue the reaction for 48 h, to obtain the mixture 3 of the antioxidant; (4) Finally, filter the mixture, and then remove the solvent in the solution by rotary evaporation, to obtain the multi-effect antioxidant.

[0030] Example 4 The preparation method of the multi-effect antioxidant is as follows: (1) Put 4.6 g 2,3,4-trihydroxybenzophenone, 3.0 g 4-formylphenylboronic acid and 500 ml N,N-dimethylformamide into a 1000 ml round-bottom flask, add 12 g anhydrous calcium sulfate dehydrating agent, keep the nitrogen environment in the round-bottom flask, control the reaction temperature at 85 °C, and continue the reaction for 24 h, to obtain the mixture 1; (2) To the mixture 1, add 3.68 g p-aminodiphenylamine, control the reaction temperature at 40 °C, and continue the reaction for 36 h, to obtain the mixture 2; (3) To the mixture 2, add 3.32 g dipropyl phosphite, control the reaction temperature at 40 °C, and continue the reaction for 48 h, to obtain the mixture 3 of the antioxidant; (4) Finally, filter the mixture, and then remove the solvent in the solution by rotary evaporation, to obtain the multi-effect antioxidant.

[0031] Example 5 The preparation method of the multi-effect antioxidant is as follows: (1) Put 4.6 g 2,3,4-trihydroxybenzophenone, 3.0 g 4-formylphenylboronic acid and 500 ml N,N-dimethylformamide into a 1000 ml round-bottom flask, add 10 g anhydrous magnesium sulfate dehydrating agent, keep the nitrogen environment in the round-bottom flask, control the reaction temperature at 100 °C, and continue the reaction for 10 h, to obtain the mixture 1; (2) To the mixture 1, add 3.68 g p-aminodiphenylamine, control the reaction temperature at 80 °C, and continue the reaction for 12 h, to obtain the mixture 2; (3) To the mixture 2, add 4.98 g dipropyl phosphite, control the reaction temperature at 60 °C, and continue the reaction for 60 h, to obtain the mixture 3 of the antioxidant; (4) Finally, filter the mixture, and then remove the solvent in the solution by rotary evaporation, to obtain the multi-effect antioxidant.

[0032] Example 6 The preparation method of the multi-effect antioxidant is as follows: (1) 4.6 g of 2,3,4-trihydroxybenzophenone, 3.0 g of 4-formylphenylboronic acid and 500 ml of N,N-dimethylformamide are added to a 1000 ml round bottom flask, while adding 12 g of anhydrous magnesium sulfate dehydrating agent, and the nitrogen environment is maintained in the round bottom flask, the reaction temperature is controlled at 85°C, and the reaction time is 24 h to obtain a mixture 1; (2) 3.68 g of p-aminodiphenylamine is added to the above mixture 1, the reaction temperature is controlled at 45°C, and the reaction time is 36 h to obtain a mixture 2; (3) 3.88 g of dibutyl phosphite is added to the above mixture 2, the reaction temperature is controlled at 45°C, and the reaction time is continuously reacted for 48 h to obtain an antioxidant mixture 3; (4) Finally, the above mixture is filtered, and then the solvent in the solution is removed by rotary evaporation to obtain the multi-effect antioxidant.

[0033] Example 7 The preparation method of the multi-effect antioxidant is as follows: (1) 4.6 g of 2,3,4-trihydroxybenzophenone, 3.0 g of 4-formylphenylboronic acid and 500 ml of N,N-dimethylformamide are added to a 1000 ml round bottom flask, while adding 10 g of anhydrous magnesium sulfate dehydrating agent, and the nitrogen environment is maintained in the round bottom flask, the reaction temperature is controlled at 100°C, and the reaction time is 10 h to obtain a mixture 1; (2) 3.68 g of p-aminodiphenylamine is added to the above mixture 1, the reaction temperature is controlled at 80°C, and the reaction time is 12 h to obtain a mixture 2; (3) 5.82 g of dibutyl phosphite is added to the above mixture 2, the reaction temperature is controlled at 60°C, and the reaction time is continuously reacted for 60 h to obtain an antioxidant mixture 3; (4) Finally, the above mixture is filtered, and then the solvent in the solution is removed by rotary evaporation to obtain the multi-effect antioxidant.

[0034] Example 8 The preparation method of the multi-effect antioxidant is as follows: (1) 4.6 g of 2,3,4-trihydroxybenzophenone, 3.0 g of 4-formylphenylboronic acid and 500 ml of N,N-dimethylformamide are added to a 1000 ml round bottom flask, while adding 12 g of anhydrous calcium sulfate dehydrating agent, and the nitrogen environment is maintained in the round bottom flask, the reaction temperature is controlled at 90°C, and the reaction time is 24 h to obtain a mixture 1; (2) 3.68 g of p-aminodiphenylamine is added to the above mixture 1, the reaction temperature is controlled at 60°C, and the reaction time is 28 h to obtain a mixture 2; (3) To the mixture 2, 2.07 g of diethyl phosphite and 2.91 g of dibutyl phosphite were added, and the reaction temperature was controlled at 45°C, and the reaction time was continued for 44 h to obtain the mixture 3 of the anti-aging agent; (4) Finally, the mixture was filtered, and the solvent in the solution was removed by rotary evaporation to obtain the multi-effect anti-aging agent.

[0035] Performance test: The butadiene styrene rubber was used as the rubber matrix, the traditional anti-aging agent 4020 was used as the reference sample, and the synthesized anti-aging agent was used as the comparative sample. The sample codes are shown in Table 1. The butadiene styrene rubber formula prepared was consistent in other components except for the different anti-aging agent components. The specific components were as follows: butadiene styrene rubber 100 parts; carbon black (N220) 35 parts; zinc oxide 5.0 parts; stearic acid 2.0 parts; accelerator CZ 1.8 parts; sulfur 2 parts; anti-aging agent 5 parts.

[0036] Table 1 Sample codes of different types of butadiene styrene rubber

[0037] The rubber was mixed using an open mill, and the roller temperature was room temperature. The cooling water needed to be turned on during the mixing process. The butadiene styrene rubber was plasticized several times, and then the stearic acid, zinc oxide, prepared anti-aging agent, accelerator CZ, sulfur, and carbon black (N220) were added to the rubber compound. The rubber was mixed and rolled, and finally, the triangle bag and thin pass were rolled for 4 times before the sheet was taken out. After one day of storage, the sample was mixed on the open mill for three times, and the sheet was taken out. The butadiene styrene rubber sample was prepared by vulcanization at 150°C and 20 MPa using a flat press.

[0038] The ultraviolet light aging was tested according to the GB / 14522-2008 standard. The prepared rubber sample was placed in an aging oven, and the sample was 25 cm away from the ultraviolet lamp tube. After 5 days of aging, the sample was taken out. Then the sample was transferred to a thermal oxygen aging oven, and the thermal oxygen aging test was carried out according to the GB / T13939-2014 standard. The temperature of the aging oven was 100°C, and the sample was vertically hung in the oven. The hot air in the oven was circulated.

[0039] The mechanical properties of the rubber sample were determined according to the GB / T528-2009 standard for the determination of the tensile stress and strain properties of vulcanized rubber or thermoplastic rubber. The dumbbell-shaped sample was prepared, and the tensile rate was 500 mm / min.

[0040] The calculation formula for the retention rate of the tensile strength and elongation at break of the aged rubber was: the tensile strength or elongation at break of the aged sample / the tensile strength and elongation at break of the unaged sample x 100%.

[0041] The test results of some samples are shown in Table 2.

[0042] Table 2 Anti-aging performance test results of styrene butadiene rubber

[0043] As can be seen from Table 2, compared with adding conventional anti-aging agents, adding the multi-effect rubber anti-aging agent prepared in Examples 1-8, the anti-aging performance of the styrene butadiene rubber product has been significantly improved. The results of the ultraviolet-thermal oxygen combined aging test show that the tensile properties and elongation at break of the styrene butadiene rubber sample after aging are significantly better than those of the sample without adding the anti-aging agent, and also better than those of the styrene butadiene rubber with the addition of the conventional anti-aging agent, which can be mainly attributed to the fact that the multi-effect anti-aging agent prepared in the application has both ultraviolet light absorption function and thermal oxygen aging resistance, in addition, the prepared anti-aging agent has a large molecular weight, which can slow down or reduce the migration and precipitation of the anti-aging agent in the aging test, and at the same time has good compatibility with the styrene butadiene rubber, basically does not affect the mechanical properties of the rubber product when the amount of addition is not much, thereby improving the anti-aging performance of the rubber product.

[0044] In summary, the application includes but is not limited to the above examples, any equivalent replacement or partial improvement made under the spirit and principles of the application will be considered within the protection scope of the application.

Claims

1. A process for the preparation of a multi-functional antioxidant, characterized by: The method steps include: S1, 2, 3, 4-trihydroxybenzophenone and 4-formylphenylboronic acid are added to a solvent, and an excess of a dehydrating agent is added, a dehydration reaction occurs between the boronic acid group and the o-diphenol group to obtain a mixture containing intermediate product 1; S2, p-aminodiphenylamine is added to the mixture containing intermediate product 1, and an imination reaction occurs between the aldehyde group and the amino group to obtain a mixture containing intermediate product 2; S3, a monomer containing a phosphorus-hydrogen bond is added to the mixture containing intermediate product 2, and an addition reaction occurs between the phosphorus-hydrogen bond and the imine bond to obtain a mixture 3 containing an antioxidant; S4, the mixture 3 containing the antioxidant is filtered, and the solvent is removed by rotary evaporation to obtain a multi-effect antioxidant.

2. The method for preparing a multi-effect anti-aging agent as described in claim 1, characterized in that: In step S1, the solvent is N, N-dimethylformamide; And / or, the molar ratio of 2, 3, 4-trihydroxybenzophenone to 4-formylphenylboronic acid is 1:1; And / or, the dehydrating agent is one or more of magnesium sulfate, calcium sulfate, and calcium chloride.

3. The method for preparing a multi-effect anti-aging agent as described in claim 1 or 2, characterized in that: In step S1, the reaction temperature is 80-100℃, and the reaction time is 10-24h.

4. The method for preparing a multi-effect anti-aging agent as described in claim 1, characterized in that: In step S2, the molar ratio of p-aminodiphenylamine to 4-formylphenylboronic acid in step S1 is 1:

1.

5. A method for preparing a multi-effect anti-aging agent as described in claim 1 or 4, characterized in that: In step S2, the reaction temperature is 40-80℃, and the reaction time is 12-36h.

6. The method for preparing a multi-effect anti-aging agent as described in claim 1, characterized in that: In step S3, the phosphorus-hydrogen bond-containing monomer has a structure as shown in the following formula wherein R is ethyl, propyl or butyl; And / or, the molar ratio of the monomer containing a phosphorus-hydrogen bond to 4-formylphenylboronic acid in step S1 is 1-1.5:

1.

7. The method for preparing a multi-effect anti-aging agent as described in claim 6, characterized in that: In step S3, the reaction temperature is 40-60℃, and the reaction time is 24-48h.

8. A multi-functional age resistor characterized by: The anti-aging agent is prepared by the method of any one of claims 1-7, and has a structural formula ; wherein R is an alkyl group or an aryl group.

9. A multi-effect anti-aging agent as described in claim 1, characterized in that: R is ethyl, propyl, butyl, or a phenyl ring.

10. Use of the multi-functional age resistor according to claim 8 or 9, characterized in that: The multi-effect antioxidant is used as an antioxidant for rubber products.

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