Migration-resistant anti-aging agent as well as preparation method and application thereof

Abstract

The invention relates to a migration-resistant anti-aging agent as well as a preparation method and application thereof, the method comprises the following steps: taking a substance as shown in a formula I and nitric acid as reactants, condensing H in an amino para-position group-CH-H and nitryl to obtain a nitrated substance, and carrying out hydrogenation reduction on the nitryl of the nitrated substance under the action of a catalyst to obtain an intermediate product. And carrying out hydrogenation on the intermediate product and ketone under the action of a catalyst to obtain a final product, namely the migration-resistant anti-aging agent II. The raw materials are convenient to purchase and transport, the product yield is high, the cost is low, the operation is simple, and the environmental pollution is small, so that the method has an industrial development prospect. # imgabs0 #

Description

Technical Field

[0001] The invention relates to a migration-resistant antioxidant and a preparation method and application thereof, belonging to the technical field of rubber. Background Art

[0002] During the processing, storage and use of rubber, due to the combined influence of internal and external factors, aging phenomena such as softening, stickiness, hardening, cracking, brittleness, spots, mildew, loss of gloss, and color change will occur. Rubber antioxidant is a substance that can prevent or delay rubber aging. At present, p-phenylenediamine antioxidants account for most of the rubber antioxidant market. Antioxidant 4020 (N (1, 3-dimethylbutyl) -N'-phenyl p-phenylenediamine) is the most widely used rubber antioxidant. It has excellent protective properties, but its shortcomings are also obvious, such as toxicity, color pollution, poor migration resistance, etc. Among them, the most serious problem is that it is easy to migrate out of the rubber system, that is, the so-called frosting phenomenon, so that the protective effect cannot be fully exerted. Specifically, during long-term use or storage, the rubber antioxidant will migrate from the inside of the rubber product to the rubber surface, resulting in a significant reduction in the effective protective part. At present, studies have found that the loss problem caused by poor migration resistance is very serious, resulting in less than 50% of the part of the traditional antioxidant that can really play a role in the rubber.

[0003] Therefore, there is an urgent need to develop a new antioxidant with low toxicity, no color pollution and high migration resistance. Summary of the invention

[0004] In order to improve the migration resistance of traditional antioxidants, enhance the protective efficiency of antioxidants, and reduce the economic losses caused by the migration of antioxidants, the present invention provides a type of migration-resistant antioxidant and a preparation method and application thereof.

[0005] The invention improves the traditional amine antioxidant and increases the molecular weight of the traditional amine antioxidant to prepare a class of high migration resistance antioxidants, improves the shortcomings of the traditional antioxidants such as poor migration resistance and easy discoloration, and enhances the protective effect of the traditional antioxidants in rubber.

[0006] The migration-resistant antioxidant has a structure as shown in the following formula II:

[0007]

[0008] R2 and R3 are selected from, but not limited to, aminoalkyl, aminoaryl, aminoalkylaryl, and aminoarylalkyl.

[0009] The preparation method of the above-mentioned migration-resistant antioxidant comprises the following steps:

[0010] 1) Nitration: dissolving the substance described in formula I in a solvent, adding an acid mixture dropwise into the base liquid at a certain temperature, controlling the reaction temperature, and obtaining a nitrated substance;

[0011]

[0012] 2) Reduction: In a high-pressure reactor, the nitrated substance is dissolved in an organic solvent, a catalyst is added, hydrogen is introduced, the nitrated substance is reduced, the catalyst is filtered out, the solvent and water are removed, and an aminated substance is obtained;

[0013]

[0014] R1* represents amino, alkyl, aminoalkyl;

[0015] 3) Condensation: In a high-pressure reactor, the aminated substance and ketone are subjected to dehydration condensation under the action of a catalyst and hydrogen. After the reaction is completed, the ketone and the by-product alcohol are removed to obtain a migration-resistant antioxidant;

[0016]

[0017] According to the preferred embodiment of the present invention, in step 1), the substance of formula I

[0018]

[0019] R1 is selected from, but not limited to, nitro, amino, alkyl, aminoalkyl, or hydrogen.

[0020] Preferably according to the present invention, in step 1), the solvent is methanol, ethanol, isopropanol, methyl isobutyl carbinol, methyl isopropyl carbinol; the preferred solvent is ethanol.

[0021] Preferably, according to the present invention, in step 1), the mass ratio of the solvent to the substance of formula I is 8 to 16:1; preferably, the mass ratio of the solvent to the substance of formula I is 10 to 13:1.

[0022] Preferably according to the present invention, in step 1), the acid mixture is a mixture of concentrated nitric acid and concentrated sulfuric acid, and the molar ratio of concentrated nitric acid to concentrated sulfuric acid is 1-2:1. Preferably, in the acid mixture, the molar ratio of concentrated nitric acid to concentrated sulfuric acid is 1.5:1.

[0023] Preferably according to the present invention, in step 1), the molar ratio of nitric acid in the acid mixture to the substance of formula I is 1.3-1.8:1, preferably, the molar ratio of nitric acid in the acid mixture to the substance of formula I is 1.5-1.6:1.

[0024] Preferably according to the present invention, in step 1), the dripping speed of the acid mixture is controlled at 10-30 min, and the dripping time of the acid mixture is 25 min.

[0025] Preferably, according to the present invention, in step 1), the reaction temperature is -5°C-10°C, and controlling the temperature effectively reduces the formation of by-products; preferably, the reaction temperature is -2°C-2°C.

[0026] Preferably according to the present invention, in step 1), after the reaction is completed, the mother liquor is concentrated and crystallized, the solvent is recycled, the product is washed with water until neutral, and dried to obtain the nitrated substance.

[0027] Preferably according to the present invention, in step 2), the organic solvent is one or a mixture of two or more of methanol, ethanol, isopropanol, and methyl isobutyl carbinol, and preferably, the organic solvent is ethanol.

[0028] According to the preferred embodiment of the present invention, in step 2), the catalyst is one or a mixture of two or more of a copper-based catalyst, a palladium-carbon catalyst, a platinum-carbon catalyst, Raney nickel, Ranidone, and Raney palladium. Preferably, the catalyst is a Raney nickel catalyst.

[0029] According to the preferred embodiment of the present invention, in step 2), the amount of catalyst added is 1%-8% of the mass of the substance after nitration, and preferably, the amount of catalyst added is 2%-4% of the mass of the substance after nitration.

[0030] Preferably according to the present invention, in step 2), the reaction temperature is 60-100° C., and the hydrogen pressure is 1-4 MPa; preferably, the reaction temperature is 70-80° C., and the hydrogen pressure is 2-3 MPa.

[0031] Preferably according to the present invention, in step 2), after the reaction no longer consumes hydrogen, the catalyst is filtered out and recycled, the mother liquor is distilled under reduced pressure to remove water, the solvent is recycled, and the product aminated material is obtained after drying.

[0032] Preferably according to the present invention, in step 3), the mass ratio of the aminating substance to the ketone is 1:8-15, preferably, the mass ratio of the aminating substance to the ketone is 1:10-12.

[0033] Preferably according to the present invention, in step 3), the catalyst and its amount are the same as those in step 2), and the mass of the amination substance is the same as the mass of the nitration substance.

[0034] Preferably, according to the present invention, in step 3), the reaction temperature is 60-100° C., and the hydrogen pressure is 1-4 MPa; preferably, the reaction temperature is 80-90° C., and the hydrogen pressure is 3-4 MPa.

[0035] Preferably according to the present invention, in step 3), the reaction is not after hydrogen consumption, the catalyst is filtered out, recovered and reused, the mother liquor is distilled under reduced pressure to remove water, the solvent is reused, and the migration-resistant antioxidant is obtained after drying.

[0036] The technical features and advantages of the present invention are as follows:

[0037] 1. The present invention uses the substance described in Formula I and nitric acid as reactants, and the H in the amino para-group -CH- is condensed with the nitro group to obtain a nitrated substance, and the nitro group of the nitrated substance is hydrogenated and reduced under the action of a catalyst to obtain an intermediate product. The intermediate product is hydrogenated with a ketone under the action of a catalyst to obtain a final product, a migration-resistant antioxidant II. The obtained migration-resistant antioxidant has a tortuous and slender molecular chain. The formed antioxidant not only has a good anti-aging effect, but more importantly, has a slow migration speed in plastics and rubbers, high migration resistance, large capacity in plastics and rubbers, and does not spray bloom.

[0038] 2. The present invention can improve the heat-oxidative aging resistance and tensile fatigue performance of rubber while using less antioxidant, and maintain good original tensile strength, original elongation at break, static ozone aging performance and dynamic ozone aging performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The NMR spectrum of the final product obtained in Example 1;

[0040] Figure 2 The NMR spectrum of the final product obtained in Example 2;

[0041] Figure 3 This is the rubber picture after 24h of dynamic ozone aging;

[0042] Figure 4 This is the picture of the rubber after static ozone aging for 24 hours. DETAILED DESCRIPTION

[0043] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, a preparation method and application method of a new antioxidant proposed in the present invention, its specific implementation method and effects are described in detail as follows.

[0044] Example 1

[0045] The preparation method of the migration-resistant antioxidant comprises the following steps:

[0046] Using formula Ⅰ as raw material, When R1 is an aminopropyl group, Formula I is N-isopropyl-N`-phenyl-p-phenylenediamine (molecular weight 226.3);

[0047] 1) Nitrification

[0048] 22.6 g of N-isopropyl-N'-phenyl-p-phenylenediamine was dissolved in 226 g of ethanol, and 23.90 g of the acid mixture was added dropwise to the system within 30 min. The reaction temperature was controlled at 1° C. to obtain 26.3 g of the nitrated substance (molecular weight: 271). The yield based on N-isopropyl-N'-phenyl-p-phenylenediamine was 97.0%. The reaction equation is as follows:

[0049]

[0050] 2) Restore

[0051] In a 1L autoclave, 27.1g of the nitrated substance was dissolved in 271g of ethanol, 1.36g of Raney nickel catalyst was added, and hydrogen was introduced at 70°C to reduce the nitrated substance at 2MPa. The reaction was continued until the pressure in the autoclave did not change. The catalyst was filtered out, and the ethanol and water were removed under reduced pressure. The ethanol was reused to obtain 23.3g of the aminated substance (molecular weight 241). The yield of the nitrated substance was 96.7%, and the reaction equation was as follows:

[0052]

[0053] 3) Condensation

[0054] In a 1L high-pressure reactor, 24.1g of amination material, 241g of methyl isobutyl ketone, the catalyst in step 2) was reused, and hydrogen was charged at 4MPa. The reaction temperature was 80°C to carry out ketoamine dehydration condensation. After the reaction was completed, the ketone was removed by vacuum distillation for reuse and the by-product methyl isobutyl methanol to obtain 31.5g of the final product migration-resistant antioxidant (molecular weight 325). The yield of amination material was 96.9%, and the reaction equation was as follows:

[0055]

[0056] The NMR spectrum of the final product migration-resistant antioxidant is shown in Figure 1 .

[0057] Example 2

[0058] The preparation method of the migration-resistant antioxidant comprises the following steps:

[0059] Using formula Ⅰ as raw material, When R1 is nitro, Formula I is 4-nitrodiphenylamine (molecular weight 214.2).

[0060] 1) Nitrification

[0061] 21.4 g of 4-nitrodiphenylamine was dissolved in 214 g of ethanol, and 23.90 g of the acid mixture was added dropwise thereto within 30 min. The reaction temperature was controlled at -2°C to 2°C to obtain 26.4 g of the nitrated substance (molecular weight: 277). The yield based on 4-nitrodiphenylamine was 95.3%. The reaction equation is as follows:

[0062]

[0063] 2) Restore

[0064] In a 1L autoclave, 27.7g of the nitrated substance was dissolved in 277g of ethanol, 1.39g of Raney nickel catalyst was added, and hydrogen was introduced at 70°C to reduce the nitrated substance at 3MPa. The reaction was continued until the pressure in the autoclave did not change. The catalyst was filtered out, and the ethanol and water were removed under reduced pressure. The ethanol was reused to obtain 19.2g of the aminated substance (molecular weight 199). The yield of the nitrated substance (I) was 96.5%, and the reaction equation was as follows:

[0065]

[0066] 3) Condensation

[0067] In a 1L high-pressure reactor, 19.9g of amination material, 199g of methyl isobutyl ketone, the catalyst in step 2) was reused, and hydrogen was charged at 3MPa. The reaction temperature was 80°C to carry out ketoamine dehydration condensation. After the reaction was completed, the ketone was removed by vacuum distillation and reused with the by-product methyl isobutyl methanol to obtain 34.1g of the final product migration-resistant antioxidant (molecular weight 352). The yield of amination material was 96.9%. The reaction equation is as follows:

[0068]

[0069] The NMR spectrum of the final product migration-resistant antioxidant is shown in Figure 2 .

[0070] Experimental Example 1

[0071] Performance Verification

[0072] 1. Rubber formula and rubber preparation

[0073] Rubber compound formula (parts by weight): 96.25 parts of SSBR, 30 parts of BR, 80 parts of white carbon black, 5 parts of N220, 3 parts of ZnO-80, 1 part of SA, 8 parts of S175, 1 part of SA, 1.5 parts of protective wax, 1 part of RD, 2.5 parts of DPG-80, 30 parts of tread resin, 2 parts of S-80, 2 parts of CBS-80, 2 parts of antioxidant of Example 1 or Example 2. Meanwhile, the antioxidant prepared in the example of the present invention was replaced with antioxidant 4020 as a comparison, and the one without adding the antioxidant of the present invention was used as a blank control, which were respectively recorded as 1# blank, 2# 4020, 3# Example 1, and 4# Example 2.

[0074] 2. Test methods for various performance parameters of rubber materials

[0075] Processing performance test: Using Mooney viscometer, scorch test was carried out according to the national standard GB / T 1233-92.

[0076] Vulcanization characteristics: P3555 B2 disc vulcanizer produced by Beijing Huanfeng Rubber & Plastic Machinery Manufacturing Plant was used for testing according to GB / T98691997, with a test temperature of 160°C and a test time of 60 min.

[0077] Mechanical properties: CMT 4104 electronic tensile testing machine produced by Shenzhen Xinsansi Material Testing Co., Ltd. was used to measure the tensile properties of the vulcanized rubber according to GB / T 528-2009. According to GB / T 77591996, a 29.0mm×12.5mm cylindrical specimen was used to measure the compression permanent deformation at 100℃×72h with a pre-compression rate of 25%.

[0078] Ozone resistance: The ozone resistance test results evaluation standard is based on GB / T 11206-2009 "Rubber Aging Test Surface Cracking Method" for ozone resistance test. The test results are shown in Table 1. Figure 3 , Figure 4 .

[0079] Table 1

[0080]

[0081]

[0082] As can be seen from Table 1, the scorch time of the rubber compound with the addition of antioxidant becomes shorter, and the vulcanization speed of the rubber compound with the addition of the antioxidant of Example 1 or Example 2 is significantly faster than that of the 4020 rubber compound. The addition of antioxidant reduces the modulus and Tb of the rubber compound, and the elongation at break is basically the same.

[0083] 3. The status diagrams of different rubber materials 1#, 2#, 3#, and 4# after dynamic ozone aging for 24 hours and static ozone aging for 24 hours are shown in the figure below. Figure 3 , Figure 4 .

[0084] from Figure 3 It can be seen from the dynamic ozone that the protection effects of Examples 1 and 2 are basically the same as those of 4020. Figure 4 It can be seen from static ozone that Example 2 has the best protection effect, followed by 4020; Examples 1 and 2 have obvious anti-discoloration and anti-migration properties.

[0085] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been presented as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to the equivalent embodiments of the same variations using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A migration-resistant antioxidant, the structure of which is shown in the following formula II: R2 and R3 are selected from, but not limited to, aminoalkyl, aminoaryl, aminoalkylaryl, and aminoarylalkyl.

2. The method for preparing the migration-resistant antioxidant according to claim 1, comprising the following steps: 1) Nitration: dissolving the substance described in formula I in a solvent, adding an acid mixture dropwise into the base liquid at a certain temperature, controlling the reaction temperature, and obtaining a nitrated substance; 2) Reduction: In a high-pressure reactor, the nitrated substance is dissolved in an organic solvent, a catalyst is added, hydrogen is introduced, the nitrated substance is reduced, the catalyst is filtered out, the solvent and water are removed, and an aminated substance is obtained; R1* represents amino, alkyl, aminoalkyl; 3) Condensation: In a high-pressure reactor, the aminated substance and ketone are subjected to dehydration condensation under the action of a catalyst and hydrogen. After the reaction is completed, the ketone and the by-product alcohol are removed to obtain a migration-resistant antioxidant; 3. The preparation method according to claim 2, characterized in that: In step 1), the substance of formula I R1 is selected from, but not limited to, nitro, amino, alkyl, aminoalkyl, or hydrogen.

4. The preparation method according to claim 2, characterized in that: In step 1), the solvent is methanol, ethanol, isopropanol, methyl isobutyl carbinol, methyl isopropyl carbinol, and the mass ratio of the solvent to the substance described in formula I is 8 to 16:1; preferably, the mass ratio of the solvent to the substance described in formula I is 10 to 13:

1.

5. The preparation method according to claim 2, characterized in that: The acid mixture is a mixture of concentrated nitric acid and concentrated sulfuric acid, the molar ratio of concentrated nitric acid to concentrated sulfuric acid is 1-2:1, and the molar ratio of nitric acid in the acid mixture to the molar ratio of the substance described in formula I is 1.3-1.8:

1.

6. The preparation method according to claim 2, characterized in that: The dropping time of the acid mixture is controlled within 10-30 minutes, and the reaction temperature is -5°C to 10°C. Controlling the temperature effectively reduces the generation of by-products. After the reaction is completed, the mother liquor is concentrated and crystallized, the solvent is recycled, the product is washed with water to neutrality, and dried to obtain the nitrated substance.

7. The preparation method according to claim 2, characterized in that: In step 2), the organic solvent is one or a mixture of two or more selected from methanol, ethanol, isopropanol, and methyl isobutyl carbinol, and the catalyst is one or a mixture of two or more selected from copper-based catalysts, palladium-carbon catalysts, platinum-carbon catalysts, Raney nickel, ranidone, and Raney palladium.

8. The preparation method according to claim 2, characterized in that: In step 2), the amount of catalyst added is 1%-8% of the mass of the nitrated substance, the mass ratio of the nitrated substance to the organic solvent is 1:(5-20), the reaction temperature is 60-100° C., and the hydrogen pressure is 1-4 MPa; preferably, the reaction temperature is 70-80° C., the hydrogen pressure is 2-3 MPa, and after the reaction no longer consumes hydrogen, the catalyst is filtered out, recovered and reused, the mother liquor is subjected to reduced pressure distillation to remove water, the solvent is reused, and the product amination substance is obtained after drying.

9. The preparation method according to claim 2, characterized in that: In step 3), the mass ratio of the aminating substance to the ketone is 1:8-15, the catalyst and its amount are the same as in step 2), and the mass of the aminating substance is the same as the mass of the nitrating substance.

10. The preparation method according to claim 2, characterized in that: In step 3), the reaction temperature is 60-100° C. and the hydrogen pressure is 1-4 MPa; after the reaction no longer consumes hydrogen, the catalyst is filtered out and recycled for reuse. The mother liquor is distilled under reduced pressure to remove water, the solvent is reused, and the migration-resistant antioxidant is obtained after drying.

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