Rubber anti-aging agent and preparation method thereof

Abstract

The invention discloses a rubber anti-aging agent and a preparation method thereof, and belongs to the technical field of rubber anti-aging agents, and the preparation method is characterized by comprising the following steps: adding p-aminodiphenylamine and a monohydroxyl-terminated unsaturated olefin monomer into an organic solvent to form a uniform solution; adding phosphonitrilic chloride trimer into the solution, dropwise adding an organic base catalyst, and fully reacting to obtain a product solution; and filtering the solution, and performing rotary evaporation to remove the solvent to obtain the rubber anti-aging agent. The anti-aging agent has the beneficial effects that the anti-aging agent has good compatibility with current common non-polar rubber, and meanwhile, the anti-aging agent can participate in rubber vulcanization, so that migration and precipitation of the anti-aging agent in storage and use processes are reduced.

Description

Technical field:

[0001] The invention relates to the preparation of an antioxidant, in particular to a rubber antioxidant and a preparation method thereof. Background technology:

[0002] Most traditional rubber materials are non-polar rubbers, which are mainly composed of carbon, hydrogen and other elements. After adding various additives and vulcanization, rubber material elastomers can be formed. Commonly used rubbers in industry include natural rubber, styrene-butadiene rubber, butadiene rubber and nitrile rubber. The polymer chain of rubber usually contains a large number of carbon-carbon double bonds. The structure of the molecule determines the performance. The carbon-carbon double bonds of the rubber polymer chain activate the hydrogen on the allyl carbon, causing the rubber to react easily under oxygen, ozone, light and stress conditions, resulting in chain breaking and cross-linking of the rubber polymer chain, which is manifested as the degradation of the mechanical properties of the rubber polymer material, and ultimately causes the rubber product to lose its function.

[0003] The traditional strategy to solve the aging problem of rubber products is to add antioxidants. This method has low impact on the rubber processing and production process and good economic performance. Therefore, this type of antioxidant products have been well marketed. According to the structure type of antioxidants, the main varieties of antioxidants include: (1) amine antioxidants, common products include 6PPD, RD, 4010NA, etc. This type of antioxidant mainly uses the secondary amino group in the aniline structure to absorb the 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 antioxidants, usually hindered phenol antioxidants, common products include antioxidant 2246, antioxidant BHT, antioxidant SP, etc. (3) heterocyclic antioxidants, common varieties are 2-mercaptobenzimidazole, 2-mercaptobenzimidazole salt (anti-aging agent MBZ), etc.; (4) phosphite antioxidants, main varieties include antioxidant 168, antioxidant TNP, etc.

[0004] In the actual application of rubber products, thermal oxidative aging is the most important type of aging. The mechanism of action of antioxidants in rubber products is mainly to destroy the key unit reaction of thermal oxidative aging reaction. Antiaging agents are mainly divided into free radical elimination antioxidants and peroxide decomposition antioxidants. Amine, phenol, and heterocyclic antioxidants mainly eliminate active free radicals, while phosphite antioxidants are hydroperoxide decomposition antioxidants.

[0005] Amine antioxidants can effectively eliminate active free radicals. Their research is relatively mature, their market varieties are the most complete, and their prices are relatively low. However, when traditional amine antioxidants are used in rubber products, the antioxidants tend to migrate out of the rubber matrix, causing the anti-aging performance of rubber products to decline rapidly over time. Summary of the invention:

[0006] In order to solve the above problems and overcome the shortcomings of the prior art, the present invention provides a rubber antioxidant and a preparation method thereof, which can effectively solve the problem that when traditional amine antioxidants are used in rubber products, the antioxidants are easy to migrate out of the rubber matrix, causing the anti-aging performance of the rubber products to decline rapidly over time. The specific technical solution of the present invention to solve the above technical problems is: a method for preparing a rubber antioxidant, characterized in that it comprises the following steps:

[0007] S1, adding p-aminodiphenylamine and monohydroxyl-terminated unsaturated olefin monomer into an organic solvent to form a uniform solution;

[0008] S2, adding hexachlorocyclotriphosphazene to the solution, and adding an organic base catalyst dropwise, and obtaining a product solution after sufficient reaction;

[0009] S3, filtering the solution, and removing the solvent by rotary evaporation to obtain the rubber antioxidant.

[0010] Furthermore, in step S1, the organic solvent is anhydrous tetrahydrofuran or chloroform.

[0011] Furthermore, in step S1, the monohydroxy-terminated unsaturated olefin monomer is one or a mixture of two or more of farnesol, geraniol, nerol and geranylgeraniol.

[0012] Furthermore, in step S2, the organic base catalyst is one or a mixture of two or more of triethylamine, tripropylamine and tributylamine.

[0013] Furthermore, the molar ratio of p-aminodiphenylamine to hexachlorocyclotriphosphazene is (1-3):1.

[0014] Furthermore, the molar ratio of the monohydroxy-terminated unsaturated olefin monomer to hexachlorocyclotriphosphazene is (3-5):1.

[0015] Furthermore, the molar ratio of the organic base catalyst to the hexachlorocyclotriphosphazene is (2-5):1.

[0016] Furthermore, in step S2, the reaction conditions are 30-50° C., 24-48 h.

[0017] Furthermore, the rubber antioxidant preparation method prepares a rubber antioxidant.

[0018] Furthermore, the rubber antioxidant is used for preparing rubber.

[0019] The beneficial effects of the present invention are:

[0020] 1. The star-shaped rubber antioxidant prepared by the present invention has a larger addition amount than the traditional p-phenylenediamine rubber antioxidant, and basically does not affect the mechanical properties of the rubber product;

[0021] 2. Compared with traditional antioxidants, the star-shaped rubber antioxidant prepared by the present invention has good compatibility with currently common non-polar rubbers. At the same time, the antioxidant can participate in rubber vulcanization, reducing the migration and precipitation of the antioxidant during storage and use.

[0022] 3. The preparation method of the rubber antioxidant proposed in the present invention is convenient and easy, and the prepared antioxidant has excellent anti-aging performance. In addition, the antioxidant contains phosphorus and has a certain flame retardant effect. The antioxidant has a wide range of application scenarios. Description of the drawings:

[0023] Attached Figure 1 It is the chemical reaction principle diagram of the present invention: Specific implementation method:

[0024] In the description of the present invention, specific details are only for a full understanding of the embodiments of the present invention, but those skilled in the art should know that the implementation of the present invention is not limited to these details. In addition, well-known structures and functions are not described or shown in detail to avoid blurring the key points of the embodiments of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Specific implementation of the present invention:

[0026] In order to better understand the present invention, a specific embodiment is used for illustration. It is worth emphasizing that the effect of this embodiment is not substantially different from the various embodiments within the protection scope of the present invention, including the respective reagents and the content ratio of the reagents, and all of them can achieve the effects described in the present invention and solve the above-mentioned problems. Other combinations are not described here.

[0027] Example 1-A1

[0028] The preparation method of rubber antioxidant is as follows:

[0029] (1) Dissolve 10 g of p-aminodiphenylamine and 8.38 g of geraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0030] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 9.13 g of triethylamine dropwise to the above solution under stirring to react at 30° C. for 48 h.

[0031] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0032] Example 2-A2

[0033] The preparation method of rubber antioxidant is as follows:

[0034] (1) Dissolve 3.33 g of p-aminodiphenylamine and 13.94 g of geraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0035] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 7.26 g of triethylamine dropwise to the above solution under stirring to react at 50° C. for 24 h.

[0036] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0037] Example 3-A3

[0038] The preparation method of rubber antioxidant is as follows:

[0039] (1) Dissolve 6.67 g of p-aminodiphenylamine and 11.17 g of geraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0040] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 5.52 g of triethylamine dropwise to the above solution under stirring to react at 40° C. for 36 h.

[0041] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0042] Example 4-A4

[0043] The preparation method of rubber antioxidant is as follows:

[0044] (1) Dissolve 10 g of p-aminodiphenylamine and 8.38 g of nerol monomer in 200 ml of tetrahydrofuran and stir for 5 min at room temperature to form a uniform solution.

[0045] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 5.68 g of tripropylamine dropwise to the above solution under stirring to react at 35° C. for 48 h.

[0046] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0047] Example 5-A5

[0048] The preparation method of rubber antioxidant is as follows:

[0049] (1) Dissolve 3.33 g of p-aminodiphenylamine and 13.94 g of nerol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0050] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 9.26 g of tributylamine dropwise to the above solution under stirring to react at 45° C. for 36 h.

[0051] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0052] Example 6-A6

[0053] The preparation method of rubber antioxidant is as follows:

[0054] (1) Dissolve 6.67 g of p-aminodiphenylamine and 11.17 g of nerol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0055] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 7.52 g of tributylamine dropwise to the above solution under stirring to react at 40° C. for 36 h.

[0056] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0057] Example 7-A7

[0058] The preparation method of rubber antioxidant is as follows:

[0059] (1) Dissolve 10 g of p-aminodiphenylamine and 12.07 g of farnesol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0060] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 6.68 g of triethylamine dropwise to the above solution under stirring to react at 35° C. for 48 h.

[0061] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0062] Example 8-A8

[0063] The preparation method of rubber antioxidant is as follows:

[0064] (1) Dissolve 3.33 g of p-aminodiphenylamine and 20.10 g of acacia monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0065] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 8.26 g of triethylamine dropwise to the above solution under stirring to react at 40° C. for 24 h.

[0066] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0067] Example 9-A9

[0068] The preparation method of rubber antioxidant is as follows:

[0069] (1) Dissolve 6.67 g of p-aminodiphenylamine and 14.66 g of geraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0070] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 7.65 g of triethylamine dropwise to the above solution under stirring to react at 45° C. for 36 h.

[0071] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0072] Example 10-A10

[0073] The preparation method of rubber antioxidant is as follows:

[0074] (1) Dissolve 10 g of p-aminodiphenylamine and 15.77 g of geranylgeraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0075] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 4.68 g of tripropylamine dropwise to the above solution under stirring to react at 35° C. for 48 h.

[0076] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0077] Example 11-A11

[0078] The preparation method of rubber antioxidant is as follows:

[0079] (1) Dissolve 3.33 g of p-aminodiphenylamine and 26.26 g of geranylgeraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0080] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 6.16 g of triethylamine dropwise to the above solution under stirring to react at 45° C. for 24 h.

[0081] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0082] Example 12-A12

[0083] The preparation method of rubber antioxidant is as follows:

[0084] (1) Dissolve 6.67 g of p-aminodiphenylamine and 21.04 g of geraniol monomer in 200 ml of chloroform and stir for 5 min at room temperature to form a uniform solution.

[0085] (2) Add 6.30 g of hexachlorocyclotriphosphazene to the above solution, and stir to dissolve for 3 min at room temperature; then, add 6.52 g of triethylamine dropwise to the above solution under stirring to react at 40° C. for 36 h.

[0086] (3) Filter to remove insoluble matter and evaporate to remove solvent to obtain the rubber antioxidant.

[0087] Comparative Example 1-A01:

[0088] Use the procurement method to purchase the commonly used p-phenylenediamine rubber antioxidant on the market, specifically antioxidant 4020;

[0089] Comparative Example 2-A02:

[0090] Use the procurement method to purchase the commonly used p-phenylenediamine rubber antioxidant on the market, specifically antioxidant 4030;

[0091] Comparative Example 3-A03:

[0092] The preparation method is the same as that in the example, except that: in the preparation process of this comparative example, the monohydroxyl-terminated unsaturated olefin monomer is replaced with a monohydroxyl-terminated saturated alkane monomer;

[0093] Performance Testing

[0094] With styrene-butadiene rubber as the rubber matrix, traditional p-phenylenediamine rubber antioxidants, specifically antioxidants 4020 and 4030, are used as reference samples. Since the content of p-phenylenediamine in the synthetic star-shaped antioxidant is relatively low, for the convenience of comparison, the p-phenylenediamine group content in the antioxidant structure of different samples is kept basically the same. The amount of the synthetic antioxidant added in this patent is twice that of the traditional antioxidants 4020 and 4030.

[0095] Specifically:

[0096] The styrene-butadiene rubber formula of Comparative Example 1 and Comparative Example 2 is:

[0097] Styrene butadiene rubber: 100; purchased antioxidant: 2; carbon black (N330): 30; zinc oxide: 5.0; stearic acid: 2.0; accelerator CZ: 1.8; sulfur: 2.5.

[0098] The styrene-butadiene rubber formulas of Examples 1-12 and Comparative Example 3 are: styrene-butadiene rubber: 100; prepared antioxidant: 4; carbon black (N330): 30; zinc oxide: 5.0; stearic acid: 2.0; accelerator CZ: 1.8; and sulfur: 2.5.

[0099] Use an open mill to mix the rubber, the roller temperature is room temperature, and the cooling water needs to be turned on during the mixing process. First, plasticize the styrene-butadiene rubber several times, then add stearic acid, zinc oxide, antioxidant, accelerator, vulcanizer, etc. to the rubber, turn over and roll, and finally make triangle packages and thin passes 4 times before producing sheets. After parking for one day, turn over the sample three times on the open mill, produce sheets, and use a flat sheet press to vulcanize at 150℃ and 20MPa to obtain styrene-butadiene rubber samples.

[0100] The heat-oxidative aging resistance was tested in accordance with GB / T13939-2014. The temperature of the aging box was 100°C. The samples were hung vertically in the aging box and hot air was circulated in the oven.

[0101] The mechanical properties of the rubber samples were measured in accordance with GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber. Dumbbell-shaped specimens were prepared at a tensile rate of 500 mm / min.

[0102] The calculation formula for the retention rate of tensile strength and elongation at break of rubber after aging is: tensile strength or elongation at break of sample after aging / tensile strength and elongation at break of sample before aging*100%.

[0103] Table 1: Comparison of properties of styrene-butadiene rubber prepared in different embodiments and comparative examples

[0104]

[0105]

[0106] From the data analysis in Table 1, we can see that:

[0107] (1) The rubber antioxidants prepared in Examples 1 to 12 have significantly improved the anti-aging properties of styrene-butadiene rubber products; compared with the addition of traditional antioxidants 4020 and 4030, the addition of the antioxidant prepared by this patent has slightly improved the mechanical strength and elongation at break of the sample. The aging test results show that the tensile properties and elongation at break of the styrene-butadiene rubber sample after aging with the antioxidant of this patent are significantly better than the tensile strength and elongation at break of the styrene-butadiene rubber sample with the addition of the traditional antioxidant;

[0108] (2) Compared with Comparative Example 3, the tensile strength and elongation at break of the styrene-butadiene rubber obtained by preparing the antioxidant with the present invention are superior to those of Comparative Example 3 in which a monohydroxy saturated alkane monomer is added.

[0109] This can be attributed to the good compatibility of the star-shaped antioxidant prepared by this patent with styrene-butadiene rubber. Compared with the traditional p-phenylenediamine rubber antioxidant, the added amount is larger, and the mechanical properties of the rubber product are basically not affected, and the mechanical properties are slightly improved.

[0110] What is particularly important is that the monohydroxy-terminated unsaturated olefin unit in the molecular structure of the antioxidant prepared in this patent participates in the vulcanization reaction of the rubber, so that a covalent bond is formed between the prepared antioxidant and the rubber polymer chain, effectively avoiding the migration and precipitation of the antioxidant during the aging test, thereby improving the anti-aging performance of the rubber product.

[0111] The preferred implementation modes of the present invention are described in detail above in combination with the embodiments; however, the present invention is not limited to the specific details in the above implementation modes. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical scheme of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0112] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0113] In summary:

[0114] 1. The star-shaped rubber antioxidant prepared by the present invention has a smaller addition amount than the traditional p-phenylenediamine rubber antioxidant and basically does not affect the mechanical properties of the rubber product;

[0115] 2. Compared with traditional antioxidants, the star-shaped rubber antioxidant prepared by the present invention has good compatibility with currently common non-polar rubbers. At the same time, the antioxidant can participate in rubber vulcanization, reducing the migration and precipitation of the antioxidant during storage and use.

[0116] 3. The preparation method of the rubber antioxidant proposed in the present invention is convenient and easy, and the prepared antioxidant has excellent anti-aging performance. In addition, the antioxidant contains phosphorus and has a certain flame retardant effect. The antioxidant has a wide range of application scenarios.

Claims

1. A method for preparing a rubber antioxidant, characterized in that: The steps include: S1, adding p-aminodiphenylamine and monohydroxyl-terminated unsaturated olefin monomer into an organic solvent to form a uniform solution; S2, adding hexachlorocyclotriphosphazene to the solution, and adding an organic base catalyst dropwise, and obtaining a product solution after sufficient reaction; S3, filtering the solution, and removing the solvent by rotary evaporation to obtain the rubber antioxidant.

2. The method for preparing a rubber antioxidant according to claim 1, characterized in that In step S1, the organic solvent is anhydrous tetrahydrofuran or chloroform.

3. The method for preparing a rubber antioxidant according to claim 1, characterized in that In step S1, the monohydroxy-terminated unsaturated olefin monomer is one or a mixture of two or more of farnesol, geraniol, nerol and geranylgeraniol.

4. The method for preparing a rubber antioxidant according to claim 1, characterized in that In step S2, the organic base catalyst is one or a mixture of two or more of triethylamine, tripropylamine and tributylamine.

5. The method for preparing a rubber antioxidant according to claim 1, characterized in that The molar ratio of p-aminodiphenylamine to hexachlorocyclotriphosphazene is (1-3):

1.

6. The method for preparing a rubber antioxidant according to claim 1, characterized in that The molar ratio of the monohydroxyl-terminated unsaturated olefin monomer to the hexachlorocyclotriphosphazene is (3-5):

1.

7. The method for preparing a rubber antioxidant according to claim 1, characterized in that The molar ratio of the organic base catalyst to the hexachlorocyclotriphosphazene is (2-5):

1.

8. The method for preparing a rubber antioxidant according to claim 1, characterized in that In step S2, the reaction conditions are 30-50° C., 24-48 h.

9. The method for preparing a rubber antioxidant according to any one of claims 1 to 8, characterized in that The method for preparing a rubber antioxidant is used for preparing a rubber antioxidant.

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