A raw rubber composition and an anti-aging agent composition

Abstract

The application relates to a raw rubber composition and an anti-aging agent composition, the raw rubber composition comprising: raw rubber, and alkylated diphenylamine of the application. The alkylated diphenylamine contained in the rubber composition of the application comprises a high content of C9 disubstituted diphenylamine, a low proportion of small molecular weight components, good compatibility with rubber, is not easy to precipitate, has better long-term protection effect, even if used alone, has application effect in protecting production and processing of synthetic rubber and long-term storage, and has better effect when used in combination with a phenolic antioxidant such as an antioxidant 1520 analogue (antioxidant 1530).

Description

Technical Field

[0001] This invention belongs to the field of functional additives for polymer materials, and particularly relates to the application of an antioxidant composition in raw rubber. Background Technology

[0002] Rubber is a highly elastic polymer material with reversible deformation, and it is divided into two types: natural rubber and synthetic rubber. Natural rubber is made by extracting latex from plants such as rubber trees and rubber grass, while synthetic rubber is obtained by polymerization reactions of various monomers. Rubber is used to manufacture tires, automotive parts, medical equipment, and more. During use and storage, rubber and its products are easily affected by light, heat, ozone, etc., leading to aging and changes in their physical and mechanical properties. This results in destructive changes such as cracking, stickiness, hardening or softening, powdering, discoloration, and mold growth. To address the problem of rubber aging, it is necessary to add appropriate additives to the rubber to inhibit or delay the aging process and extend its service life.

[0003] Patent CN111253621B discloses a combination of hindered phenolic antioxidants and aromatic amine antioxidants for use in raw rubber to prevent gelation and thermo-oxidative aging at high temperatures. However, in application, aging phenomena have been observed in raw rubber during storage, especially in raw rubber stored and used for extended periods, which still cannot be effectively resolved.

[0004] There remains a need in the field for antioxidants and their compositions suitable for improving the stability of raw rubber. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a raw rubber composition comprising:

[0006] Raw rubber, and

[0007] Alkylated diphenylamine, wherein the alkylated diphenylamine comprises:

[0008] 90.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0009]

[0010] R1 is independently selected from straight-chain or branched C9 alkyl groups.

[0011] Secondly, this application provides an anti-aging agent composition comprising:

[0012] i) Alkylated diphenylamine, wherein the alkylated diphenylamine comprises:

[0013] 0-15% of a monoalkyl diphenylamine of Formula I, based on the total weight of the alkylated diphenylamine;

[0014] 90.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0015] 0-10% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine;

[0016]

[0017] R1 is independently selected from straight-chain or branched C9 alkyl groups;

[0018] ii) Hindered phenolic antioxidants of formula IV

[0019]

[0020] R2 is selected from C1-C9 alkyl groups;

[0021] R4 is selected from C1-C9 alkyl groups or -CH2-SR. 41 R 41 Alkyl groups selected from C1-C20;

[0022] R3 is selected from -CH2-SR 41 Or -CH2-CH2-COO-R5, where R5 is selected from C1-C20 alkyl groups;

[0023] iii) Optional phosphite antioxidants; and

[0024] iv) Optional ultraviolet absorber.

[0025] Thirdly, this application also provides a raw rubber composition comprising:

[0026] Raw rubber, and

[0027] The anti-aging composition of the second aspect of this application.

[0028] Fourthly, this application provides a rubber article formed from the raw rubber composition of the first and second aspects of this application.

[0029] Fifthly, this application also relates to the use of alkylated diphenylamine in the preparation of rubber products.

[0030] The alkylated diphenylamine contained in the rubber composition of this application has a high content of C9 disubstituted diphenylamine, a low proportion of small molecular weight components, good compatibility with rubber, and is not easy to precipitate, thus having a better long-term protective effect. Even when used alone, it has a good effect on protecting synthetic rubber in production, processing and long-term storage. Furthermore, when used in combination with phenolic antioxidants such as antioxidant 1520 analogues (antioxidant 1530), the effect is even better. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0032] The alkyl groups of C1-C9 mentioned in this application are selected from C1, C2, C3, C4, C5, C6, C7, C8, C9 ... 7、 C8 and C9 alkyl groups, for example, include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, hexyl, cyclohexyl, heptyl, octyl, isooctyl, tert-octyl, nonyl, isononyl.

[0033] In this application, "optional" means either including or excluding, for example, "optional A" means including or excluding A.

[0034] In a first aspect, this application provides an anti-aging agent composition comprising:

[0035] i) Alkylated diphenylamine, wherein the alkylated diphenylamine comprises:

[0036] 90.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0037]

[0038] R1 is independently selected from straight-chain or branched C9 alkyl groups;

[0039] ii) Hindered phenolic antioxidants of formula IV

[0040]

[0041] R2 is selected from C1-C9 alkyl groups;

[0042] R4 is selected from C1-C9 alkyl groups or -CH2-SR. 41 R 41 Alkyl groups selected from C1-C20;

[0043] R3 is selected from -CH2-SR 41 Or -CH2-CH2-COO-R5, where R5 is selected from C1-C20 alkyl groups;

[0044] iii) Optional phosphite antioxidants; and

[0045] iv) Optional ultraviolet absorber.

[0046] The anti-aging agent composition comprises alkylated diphenylamine. In some embodiments, the alkylated diphenylamine further comprises:

[0047] 0-15% of a monoalkyl diphenylamine of formula I, based on the total weight of the alkylated diphenylamine; and / or

[0048] 0-10% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine;

[0049] .

[0050] In some embodiments, R1 is a straight-chain or branched C9 alkyl group. Examples of branched C9 alkyl groups include isononyl, methyl octyl, dimethyl heptyl, propyl hexyl, methyl ethyl hexyl, ethyl heptyl, trimethyl hexyl, tetramethyl pentyl, dimethyl ethyl pentyl, diethyl pentyl, butyl pentyl, etc.

[0051] In some embodiments, the alkylated diphenylamine comprises:

[0052] 0-10% of a monoalkyl diphenylamine of formula I, based on the total weight of the alkylated diphenylamine;

[0053] 90.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0054] 0-10% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine.

[0055] In some embodiments, the alkylated diphenylamine comprises:

[0056] 0-5% of a monoalkyl diphenylamine of Formula I, based on the total weight of the alkylated diphenylamine;

[0057] 92.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0058] 1-5% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine.

[0059] The anti-aging agent composition of this application comprises alkylated diphenylamine, which has a high content of bis-C9 alkyl-substituted diphenylamine (based on the total weight of the alkylated diphenylamine, the bis-C9 alkyl-substituted diphenylamine of formula II accounts for more than 90%) and a low content of mono-C9 alkyl-substituted and tri-substituted diphenylamine (based on the total weight of the alkylated diphenylamine, the mono-C9 alkyl-substituted diphenylamine of formula I and the tri-substituted diphenylamine of formula III account for less than 10%). Compared with conventional low-content bis-C9 alkyl-substituted diphenylamine products on the market, the alkylated diphenylamine of this application has a low proportion of small molecular weight components, exhibits superior resistance to heat loss, thermal stability, and low volatility, good compatibility with rubber, is less prone to precipitation, and provides better long-term protection.

[0060] In some embodiments, the amount of dialkyldiphenylamine of Formula II, based on the total weight of the alkylated diphenylamine, can be 90.0% to 99.9%, for example, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, etc. In some embodiments, the amount of monoalkyldiphenylamine of Formula I, based on the total weight of the alkylated diphenylamine, is 0% to 15%, for example, 0% to 10%, for example, less than 8%, less than 6%, less than 5%, less than 4%; or more than 0.05%, or more than 0.1%, or more than 0.5%, etc. In some embodiments, the amount of trialkyldiphenylamine of Formula III, based on the total weight of the alkylated diphenylamine, is 0% to 10%, for example, 1% to 8%, 1% to 6%, 1% to 5%, 1% to 4%, etc.

[0061] The alkylated diphenylamine of this application can be obtained by reacting tripropylene (nonene) with diphenylamine. For example, tripropylene (nonene) and diphenylamine can be reacted in the presence of Lewis acids (such as metal halides such as aluminum trichloride or zinc chloride, or acidic catalysts such as sulfuric acid, phosphoric acid, or acidic clay, etc.) to obtain a reaction product containing a dialkyldiphenylamine of formula II (see JP Japanese Patent Application Publication No. 2-188555). US5449829 also discloses another method for preparing alkylated diphenylamine, which involves reacting ammonia with an alkyl-substituted phenol in the presence of a catalyst (such as a Pd / C catalyst) and an alkyl-substituted cyclohexanone, thereby obtaining a reaction product containing a dialkyldiphenylamine of formula II. CN106944142A also discloses a method for preparing nonyldiphenylamine amine antioxidants. It should be noted that the reaction products obtained by these methods, in addition to containing a dialkyldiphenylamine of formula II, also contain a certain amount of a monoalkyldiphenylamine of formula I and a trialkyldiphenylamine of formula III. Furthermore, the content of dialkyldiphenylamine in Formula II is typically low, generally not exceeding 80 wt%, while the content of monoalkyldiphenylamine in Formula I is relatively high (generally exceeding 15 wt%). As mentioned above, such products with low content of bis-C9 alkyl-substituted diphenylamine and high content of monoalkyldiphenylamine suffer from defects in thermal stability and long-term thermal stability under high-temperature conditions, and are not suitable for direct use as the alkylated diphenylamine of this application (which has a high content of bis-C9 alkyl-substituted diphenylamine (based on the total weight of the alkylated diphenylamine, bis-C9 alkyl-substituted diphenylamine of Formula II accounts for more than 90%) and a low content of mono-C9 alkyl-substituted and tri-substituted diphenylamine (based on the total weight of the alkylated diphenylamine, mono-C9 alkyl-substituted diphenylamine of Formula I and tri-substituted diphenylamine of Formula III account for less than 10%)). The resulting reaction contents need to be treated to increase the content of bis-C9 alkyl-substituted diphenylamine of Formula II and reduce the total content of mono-C9 alkyl-substituted and tri-C9 alkyl-substituted diphenylamines. For example, the reaction contents can be treated using known techniques such as distillation (e.g., thin-film evaporation, rectification, or flash evaporation), dialysis, or chromatographic separation to control the amount of dialkyldiphenylamine of Formula II, monoalkyldiphenylamine of Formula I, and trialkyldiphenylamine of Formula III to reach the ranges defined in this application, thereby obtaining the alkylated diphenylamine of this application. Preferably, the reaction contents can be removed by rectification to remove the monosubstituted and trisubstituted components, thereby obtaining the alkylated diphenylamine of this application, which has a high content of bis-C9 alkyl-substituted diphenylamine (based on the total weight of the alkylated diphenylamine, bis-C9 alkyl-substituted diphenylamine of Formula II accounts for more than 90%) and a low content of mono-C9 alkyl-substituted and trisubstituted diphenylamine (based on the total weight of the alkylated diphenylamine, mono-C9 alkyl-substituted diphenylamine of Formula I and trisubstituted diphenylamine of Formula III account for less than 10%). During the rectification process, the content of each component can be monitored in real time, and the rectification process is stopped when the content of each component meets the requirements.The content of each component in the alkylated diphenylamine of this application can be determined by methods such as UPLC and GC.

[0062] The anti-aging composition further comprises a hindered phenolic antioxidant, such as a hindered phenolic antioxidant of formula IV. In some embodiments, R2 is selected from C1-C9 alkyl groups, preferably C1-C4 alkyl groups, more preferably methyl or tert-butyl. In some embodiments, R2 is selected from methyl or tert-butyl, and R4 is selected from -CH2-SR. 41 R3 is selected from -CH2-SR 41 R 41 The alkyl group is selected from C8-C12; the hindered phenolic antioxidant of formula IV can be 4,6-bis(octylthiomethyl)o-cresol (antioxidant 1520) or 2,4-bis(dodecylthiomethyl)-6-methylphenol (antioxidant 1026).

[0063] In some embodiments, R2 is selected from methyl or tert-butyl, and only one of R4 and R3 is -CH2-SR. 41 R 41 The alkyl group is selected from C8-C12; the hindered phenolic antioxidant of formula IV can be 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (isooctyl ester) (antioxidant 1135R), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate C7~C9 alcohol mixture ester (antioxidant 1135), 3,5-di-tert-butyl-4-hydroxyphenylpropionate C12~C14 alcohol mixture ester, 3,5-di-tert-butyl-4-hydroxyphenylpropionate C13~C15 alcohol mixture ester, 3,5-di-tert-butyl-4-hydroxyphenylpropionate C14~C16 alcohol mixture ester, or 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester (antioxidant 1076).

[0064] In some embodiments, R2 is selected from methyl or tert-butyl, R4 is selected from methyl or tert-butyl, R3 is selected from -CH2-CH2-COO-R5, and R5 is selected from C8-C18 alkyl groups.

[0065] In some embodiments, the hindered phenolic antioxidant of formula IV may be selected from at least one of the following formulas (IVa), (IVb), (IVc), and (IVd).

[0066] (IVa) (IVb)

[0067] (IVc) (IVd).

[0068] In some embodiments, the hindered phenolic antioxidant is selected from one or more of the following general formula V.

[0069] (V)

[0070] Wherein, R is a C7-C18 alkyl group.

[0071] In some embodiments, R is selected from at least one of C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, and C18 alkyl groups; or, R is selected from at least one of C7-9, C12-18, C13-15, C14-16, C12-17, C12-16, C13-16, C12-14, and C16-18 alkyl groups.

[0072] In some embodiments, the amount of alkylated diphenylamine is 10-60% (e.g., 15-60 wt%, 20-50 wt%, or 25-40 wt%, etc.), and the amount of hindered phenolic antioxidant is 10-80% (e.g., 15 wt%, 20 wt%, 30 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 75 wt%, etc.), based on the total weight of the anti-aging agent composition. Diphenylamine antioxidants are light yellow or yellow. When the proportion of diphenylamine exceeds 60% of the anti-aging composition, its addition to raw rubber will affect the color of the rubber itself; when the proportion of diphenylamine is less than 10% of the anti-aging composition, the amount added is too small, resulting in insufficient antioxidant capacity and failing to provide adequate protection.

[0073] The alkylated diphenylamine of this application exhibits a synergistic effect when used in conjunction with phenolic antioxidants, such as thioester antioxidants. During the storage of raw rubber, unsaturated double bonds readily react with oxygen to produce peroxide radicals (ROO•). These peroxide radicals then abstract hydrogen atoms from the rubber polymer molecule, producing hydroperoxides (ROOH). Hydroperoxide compounds are unstable and decompose into hydroxyl radicals (•OH) and alkoxy radicals (RO•). Alkoxy radicals can also abstract hydrogen atoms from the polymer molecule, transforming stable rubber polymer molecules into unstable free radicals that continue to react with oxygen. The alkylated diphenylamine of this application can provide hydrogen atoms to peroxide radicals (ROO•) to generate hydroperoxides (ROOH), thereby preventing peroxide radicals from abstracting hydrogen atoms from the rubber polymer molecule; while thioester antioxidants can react with hydroperoxides (ROOH) to generate stable compounds, preventing the generation of new free radicals. The synergistic effect of the alkylated diphenylamine and phenolic antioxidants, such as thioester antioxidants, in this application can prevent the accumulation of free radicals in the rubber and protect the rubber's properties from degradation.

[0074] The anti-aging composition may also include one or more of phosphite antioxidants and ultraviolet absorbers.

[0075] In some embodiments, the phosphite antioxidant is preferably a liquid phosphite, such as one or more selected from tris(nonylphenyl) phosphite (antioxidant TNPP), diphenyl isodecyl phosphite (antioxidant DPDP), diphenyl diisodecyl phosphite (antioxidant PDDP), triphenyl phosphite (antioxidant TPPi), diisopropanol ether diphenyl phosphite (antioxidant THOP), tris(a mixture of 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phosphite) (CAS: 939402-02-5, antioxidant 705), triisodecyl phosphite (antioxidant PL-81), and pentaerythritol diisodecyl diphosphite (antioxidant PL90). In some embodiments, the amount of phosphite antioxidant is 20-70% (e.g., 25wt%, 30wt%, 35wt%, 40wt%, 50wt%, or 60wt%), based on the total weight of the anti-aging agent composition.

[0076] In some embodiments, the ultraviolet absorber may be selected from 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole (UV-234), the reaction product of 3-benzotriazole-5-tert-butyl-4-hydroxyphenyl propionate and C7-C9 alcohol (UV-384-2), the reaction product of 3-benzotriazole-5-tert-butyl-4-hydroxyphenyl propionate and PEG-300 (UV-1130), and 2-[4-[2-hydroxy-3-tetrazoxypropyl]oxy]-2-hydroxyphenyl] One or more of the following: a mixture of 4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-[2-hydroxy-3-dodecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (UV-400), bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (UV-123), and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (UV-770). In some embodiments, the amount of the ultraviolet absorber is 10-60% (e.g., 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 50 wt%, or 55 wt%), based on the total weight of the anti-aging agent composition.

[0077] The alkylated diphenylamine of this application can be applied to raw rubber alone or in combination with hindered phenolic antioxidants.

[0078] Secondly, this application provides a raw rubber composition comprising:

[0079] Raw rubber, and

[0080] Alkylated diphenylamine, wherein the alkylated diphenylamine comprises:

[0081] 90.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0082]

[0083] R1 is independently selected from straight-chain or branched C9 alkyl groups.

[0084] It should be noted that the embodiments of alkylated diphenylamine in the first aspect also apply to the second aspect of this application, and will not be repeated here.

[0085] In some embodiments, the alkylated diphenylamine further includes:

[0086] 0-10% of a monoalkyl diphenylamine of formula I, based on the total weight of the alkylated diphenylamine; and / or

[0087] 0-10% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine;

[0088] .

[0089] In some embodiments, the alkylated diphenylamine comprises:

[0090] 0-5% of a monoalkyl diphenylamine of Formula I, based on the total weight of the alkylated diphenylamine;

[0091] 92.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine;

[0092] 1-5% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine.

[0093] Research has found that the long-term storage stability of raw rubber products has always been a difficult problem to solve in the industry. This long-term stability issue is related to two factors: firstly, the structure of the antioxidant composition itself; and secondly, the partial degradation of the anti-aging agent composition over time during long-term use, especially the degradation of aromatic amine antioxidants, which leads to a weakening of the rubber's long-term aging performance. Therefore, a superior antioxidant composition is still needed to meet the long-term anti-aging requirements of rubber. The alkylated diphenylamine contained in the rubber composition of this application has a high content of C9 disubstituted diphenylamine, a low proportion of small molecular weight components, good compatibility with rubber, and is not easy to precipitate, thus providing better long-term protection. Even when used alone, its effect in protecting synthetic rubber during production, processing, and long-term storage is better than that of currently used 5057 (the reaction product of N-phenylaniline and 2,4,4-trimethylpentene, CAS: 68411-46-1) and 5067 (CAS: 36878-20-3, including 23% nonyldiphenylamine, 74% dinonyldiphenylamine, and 3% trinonyldiphenylamine). Furthermore, its effect is even better when used in combination with phenolic antioxidants such as antioxidant 1520 and its analogues (e.g., antioxidant 1530). As a result, the rubber composition of this application has more stable properties, and the yellow index of raw rubber hardly changes after long-term storage.

[0094] In some embodiments, the amount of alkylated diphenylamine used is 0.1wt%-1.0wt%, preferably 0.2wt%-0.6wt%, based on the total weight of raw rubber.

[0095] Thirdly, this application provides a raw rubber composition comprising:

[0096] Raw rubber, and

[0097] The anti-aging composition of the first aspect of this application.

[0098] In some embodiments, the amount of the anti-aging agent composition is 0.1wt%-1.0wt%, preferably 0.2wt%-0.6wt%, based on the total weight of raw rubber.

[0099] For the second and third aspects, the raw rubber can be natural rubber and raw rubber synthesized by solution polymerization; more preferably, the raw rubber is one or more of polybutadiene, polyisoprene, polybutadiene-styrene copolymer, styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-butadiene block copolymer, and hydrogenated styrene-isoprene block copolymer.

[0100] When the antioxidant used in this application is applied to raw rubber, it is added to the rubber in the following manner: i) dissolving and diluting the antioxidant and the composition using a solvent; ii) adding the uniformly mixed and diluted antioxidant solution to the raw rubber. These solvents are generally consistent with the solvents used in rubber production, such as hexane, cyclohexane, n-hexane, pentane, etc.

[0101] The anti-aging agent composition of this application is highly efficient in rubber, has a low total cost, and has a better market competitive advantage. During the long-term storage of rubber, it better protects the performance of rubber and extends the service life of rubber. The rubber composition of this application has good long-term stability and fast onset of action, and can achieve good processing stability without the addition of phosphite antioxidants.

[0102] Fourthly, this application also relates to a rubber article that can be formed from the raw rubber composition of the second and third aspects of this application. For example, the raw rubber composition of the second and third aspects of this application can be vulcanized under suitable conditions to mold it into a wide variety of rubber articles, such as tires, sealing articles, shock-absorbing articles, pipes, anti-corrosion materials, medical supplies, insulating materials, etc.

[0103] Fifthly, this application also relates to the use of the alkylated diphenylamine of this application in the preparation of rubber articles. As described in the first aspect of this application, the alkylated diphenylamine will not be repeated here. The alkylated diphenylamine can be used alone or in combination with other components in the preparation of rubber articles. For example, the alkylated diphenylamine or an anti-aging agent composition containing the alkylated diphenylamine can be added to raw rubber, followed by vulcanization to mold it into various types of rubber articles. Alternatively, the alkylated diphenylamine or an anti-aging agent composition containing the alkylated diphenylamine can be added after the raw rubber has been vulcanized, and then molded into various types of rubber articles.

[0104] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the operations involved in the embodiments are conventional techniques in the art.

[0105] Raw materials used in the examples

[0106] RIANOX 1530:

[0107]

[0108] RIANOX 1520: 4,6-Di(octylthiomethyl)o-cresol, CAS: 110553-27-0;

[0109] RIANOX 5057: The reaction product of N-phenylaniline and 2,4,4-trimethylpentene, CAS: 68411-46-1;

[0110] RIANOX 5067: CAS: 36878-20-3, comprising 23% nonyldiphenylamine, 74% dinonyldiphenylamine, and 3% trinonyldiphenylamine.

[0111] Example 1

[0112] 60.00 g of diphenylamine, 44.76 g of tripropylene, and 8 g of acidic clay catalyst were placed together in a 500 ml four-necked flask. The mixture was heated to 160 °C and refluxed. The remaining 89.52 g of tripropylene (total tripropylene 134.28 g, molar ratio of diphenylamine to tripropylene 1.0:3.0) was slowly added dropwise over a period of 4 h. The reaction temperature was controlled at 158–162 °C. After the addition was complete, the mixture was refluxed for 20–24 h. After the reaction was complete, the temperature was lowered to 90 °C and the acidic clay catalyst was removed by filtration. Activated carbon and activated clay were added for decolorization at 80 °C for 1–2 h, and the decolorizing agent was removed by filtration. A vacuum distillation apparatus was used, with the vacuum level controlled to <5 mmHg, and the temperature was raised to 180 °C. Unreacted tripropylene was collected until no fraction remained. The resulting product was labeled as sample-1. The composition of the product was determined by GC, and the weight percentage of each component, calculated as the total weight of nonyldiphenylamine, dinonyldiphenylamine, and trinonyldiphenylamine, is shown in Table 1.

[0113] Example 2

[0114] 60.00 g of diphenylamine, 44.76 g of tripropylene, and 8 g of acidic clay catalyst were placed together in a 500 ml four-necked flask. The mixture was heated to 160 °C and refluxed. The remaining 134.28 g of tripropylene (total tripropylene 179.04 g, molar ratio of diphenylamine to tripropylene 1.0:4.0) was slowly added dropwise over a period of 4 hours. The reaction temperature was controlled at 158–162 °C. After the addition was complete, the mixture was refluxed for 20–24 hours. After the reaction was complete, the temperature was lowered to 90 °C, and the acidic clay catalyst was removed by filtration. Activated carbon and activated clay were added for decolorization at 80 °C for 1–2 hours, and the decolorizing agent was removed by filtration. A vacuum distillation apparatus was used, with the vacuum level controlled to <5 mmHg, and the temperature was raised to 180 °C. Unreacted tripropylene was collected until no fraction remained. The resulting product was labeled as sample-2. The composition of the product was determined by GC, and the weight percentage of each component, calculated as the total weight of nonyldiphenylamine, dinonyldiphenylamine, and trinonyldiphenylamine, is shown in Table 1.

[0115] Table 1. Composition of alkylated diphenylamine antioxidants prepared in Examples 1 and 2

[0116]

[0117] Example 3:

[0118] A liquid antioxidant composition for raw rubber, comprising the following components:

[0119] Component (a): 5g alkylated diphenylamine antioxidant sample-1;

[0120] Component (b): 5g RIANOX 1530.

[0121] Example 4:

[0122] A liquid antioxidant composition for raw rubber, comprising the following components:

[0123] Component (a): 5g alkylated diphenylamine antioxidant sample-2;

[0124] Component (b): 5g RIANOX 1530.

[0125] Example 5:

[0126] A liquid antioxidant for raw rubber, comprising the following components:

[0127] Component (a): 4g alkylated diphenylamine antioxidant sample-2;

[0128] Component (b): 6g RIANOX 1520.

[0129] Example 6:

[0130] A liquid antioxidant composition for raw rubber, comprising the following components:

[0131] Component (a): 3g alkylated diphenylamine antioxidant sample-2;

[0132] Component (b): 7g RIANOX 1530.

[0133] Example 7:

[0134] A liquid antioxidant composition for raw rubber, comprising the following components:

[0135] Component (a): 6g alkylated diphenylamine antioxidant sample-1;

[0136] Component (b): 4g RIANOX 1530.

[0137] Comparative Example 1

[0138] A liquid antioxidant for raw rubber, comprising the following components:

[0139] Component (a): 10g RIANOX 5057.

[0140] Comparative Example 2

[0141] A liquid antioxidant for raw rubber, comprising the following components:

[0142] Component (a): 10g RIANOX 5067.

[0143] Comparative Example 3

[0144] A liquid antioxidant composition for raw rubber, comprising the following components:

[0145] Component (a): 5g RIANOX 5057;

[0146] Component (b): 5g RIANOX 1530.

[0147] Comparative Example 4

[0148] A liquid antioxidant composition for raw rubber, comprising the following components:

[0149] Component (a): 5g RIANOX 5067;

[0150] Component (b): 5g RIANOX 1530.

[0151] Performance Testing - Thermal Stability of Alkylated Diphenylamine Antioxidants

[0152] The thermal stability and volatility resistance of the additives were determined using a thermogravimetric analyzer (TGA) under the following conditions:

[0153] The TGA test parameters were: temperature range 25℃~400℃, heating rate 10K / min, purge gas nitrogen 50mL / min, and sample mass 15±0.1mg. The test results are shown in Table 2. It can be seen that the thermogravimetric stability (i.e., thermal stability) of Examples 1-2 is more stable than that of the conventional products, namely Comparative Examples 1 and 2.

[0154] Table 2 Thermal stability test of additives

[0155]

[0156] Application effect data

[0157] Preparation of raw rubber samples:

[0158] 0.2 parts of the antioxidant compositions obtained from Examples 1 to 7 were added to 1 part of cyclohexane. The solutions were then added to 100 parts of a butadiene rubber resin solution. After blending, raw rubber samples 1 to 7 were obtained.

[0159] 0.2 parts of the antioxidant compositions obtained from Comparative Examples 1 to 4 were added to 1 part of cyclohexane. Then, the solutions were added to 100 parts of a butadiene rubber resin solution. After blending, raw rubber samples 8 to 11 were obtained. No antioxidant was added to raw rubber sample 12.

[0160] 1. Anti-aging color test:

[0161] The raw rubber samples 1-12 obtained above were subjected to thermo-oxidative aging tests in a 40℃ oven under light-shielding conditions. A CM-5 spectrophotometer was used, with the light source and angle set to 10 degrees from the C light source. The rubber was placed on the test platform, and the light-receiving channel was completely covered before measuring the yellow index. The test results are shown in Table 3.

[0162] Table 3: Results of thermo-oxidative aging performance test

[0163]

[0164] As shown in Table 3, after long-term storage, Examples 1 (Sample 1) and 2 (Sample 2) composed of alkylated diphenylamine antioxidants performed better in preventing rubber yellowing compared to Comparative Examples 1 (Sample 8) and 2 (Sample 9) composed of conventional 5057 and 5067. The compositions of Examples 3-7 (Samples 3-7) composed of alkylated diphenylamine antioxidants showed excellent performance in inhibiting rubber discoloration. This indicates that during long-term storage of rubber, alkylated diphenylamine antioxidants are more effective than currently used 5057 and 5067 in protecting rubber color.

[0165] 2. Mooney viscosity test: The Mooney viscosity of the raw rubber samples 1-9 obtained above was tested according to the standard in GB / T 1232.1-2016. The test results are shown in Table 4, in ML(1+4)@100℃.

[0166] Table 4: Mooney viscosity test results

[0167]

[0168] As shown in Table 4, after long-term storage, the compositions of Example 1 (Sample 1) and Example 2 (Sample 2) composed of alkylated diphenylamine antioxidants showed better performance in maintaining the Mooney viscosity of rubber compared to Comparative Example 1 (Sample 8) and Comparative Example 2 (Sample 9) composed of conventional 5057 and 5067, with a Mooney viscosity change rate of no more than 5% after 360 days of storage. The compositions of Example 3-7 (Sample 3-7) composed of alkylated diphenylamine antioxidants showed excellent performance in inhibiting rubber discoloration. The Mooney viscosity retention rates of Comparative Example 3 (Sample 10) and Comparative Example 4 (Sample 11) were not as good as those of Example 3-7 (Sample 3-7). This indicates that during long-term storage of rubber, different combinations of alkylated diphenylamine antioxidants and phenolic antioxidants are more effective in protecting the Mooney viscosity of rubber than the currently used combination of 5057, 5067 and phenolic antioxidants.

[0169] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A raw rubber composition comprising: Raw rubber, and Alkylated diphenylamine, wherein, The alkylated diphenylamine comprises: 0-15% of a monoalkyl diphenylamine of Formula I, based on the total weight of the alkylated diphenylamine; 90.0~99.9% of the dialkyldiphenylamine of formula II, based on the total weight of the alkylated diphenylamine; 0-10% of the trialkyldiphenylamine of formula III, based on the total weight of the alkylated diphenylamine; R1 is independently selected from straight-chain or branched C9 alkyl groups; Wherein, the sum of the weight contents of the monoalkyl diphenylamine, dialkyl diphenylamine and trialkyl diphenylamine is not greater than 100%, based on the total weight of the alkylated diphenylamine.

2. The raw rubber composition according to claim 1, wherein, The alkylated diphenylamine comprises: Based on the total weight of the alkylated diphenylamine, 0-10% of a monoalkyl diphenylamine of formula I; Based on the total weight of the alkylated diphenylamine, 92.0% to 99.9% of the dialkyldiphenylamine of formula II; Based on the total weight of the alkylated diphenylamine, 1-5% of the trialkyldiphenylamine of formula III; Wherein, the sum of the weight contents of the monoalkyl diphenylamine, dialkyl diphenylamine and trialkyl diphenylamine is not greater than 100%, based on the total weight of the alkylated diphenylamine.

3. The raw rubber composition according to claim 1 or 2, wherein, The alkylated diphenylamine is 0.1-1.0 wt% based on the total weight of the raw rubber.

4. The raw rubber composition according to any one of claims 1-2, wherein, The raw rubber is natural rubber or raw rubber synthesized by solution polymerization.

5. The raw rubber composition according to any one of claims 1-2, wherein, The raw rubber is one or more of polybutadiene, polyisoprene, polybutadiene-styrene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-butadiene block copolymer, and hydrogenated styrene-isoprene block copolymer.

6. A raw rubber composition comprising: A composition of raw rubber and anti-aging agents, in, The anti-aging agent composition comprises: i) Alkylated diphenylamine, wherein the alkylated diphenylamine comprises: Based on the total weight of the alkylated diphenylamine, 0-15% of a monoalkyl diphenylamine of formula I; Based on the total weight of the alkylated diphenylamine, 90.0% to 99.9% of the dialkyldiphenylamine of formula II; Based on the total weight of the alkylated diphenylamine, 0-10% of the trialkyldiphenylamine of formula III; R1 is independently selected from straight-chain or branched C9 alkyl groups; Wherein, the sum of the weight contents of the monoalkyl diphenylamine, dialkyl diphenylamine and trialkyl diphenylamine is not greater than 100%, based on the total weight of the alkylated diphenylamine; ii) Hindered phenolic antioxidants of formula IV R2 is selected from C1-C9 alkyl groups; R4 is selected from C1-C9 alkyl groups or -CH2-SR. 41 R 41 Alkyl groups selected from C1-C20; R3 is selected from -CH2-SR 41 Alternatively, -CH2-CH2-COO-R5, where R5 is selected from C1-C20 alkyl groups; at least one of R3 and R4 is -CH2-SR. 41 ; iii) Optional phosphite antioxidants; and iv) Optional ultraviolet absorber; The amount of alkylated diphenylamine is 10-60%, and the amount of hindered phenolic antioxidant is 10-80%, based on the total weight of the anti-aging agent composition.

7. The raw rubber composition according to claim 6, wherein, The alkylated diphenylamine comprises: Based on the total weight of the alkylated diphenylamine, 0-10% of a monoalkyl diphenylamine of formula I; Based on the total weight of the alkylated diphenylamine, 92.0% to 99.9% of the dialkyl diphenylamine of formula II; Based on the total weight of the alkylated diphenylamine, 1-5% of the trialkyldiphenylamine of formula III; Wherein, the sum of the weight contents of the monoalkyl diphenylamine, dialkyl diphenylamine and trialkyl diphenylamine is not greater than 100%, based on the total weight of the alkylated diphenylamine.

8. The raw rubber composition according to claim 6, wherein, R2 is selected from methyl or tert-butyl, and R4 is selected from -CH2-SR. 41 R3 is selected from -CH2-SR 41 R 41 Selected from C8-C12 alkyl groups; or R2 is selected from methyl or tert-butyl, and only one of R4 and R3 is -CH2-SR. 41 R 41 Alkyl groups selected from C8-C12.

9. The raw rubber composition according to claim 6, wherein, The amount of phosphite antioxidant is 20-70%, based on the total weight of the anti-aging agent composition; The amount of ultraviolet absorber is 10-60%, based on the total weight of the anti-aging agent composition; Wherein, the sum of the weight contents of the alkylated diphenylamine, hindered phenolic antioxidant, phosphite antioxidant and ultraviolet absorber is not greater than 100%, based on the total weight of the anti-aging agent composition.

10. The raw rubber composition according to claim 9, wherein, The hindered phenolic antioxidant is selected from one or more of 4,6-di(octylthiomethyl)-o-cresol and 2,4-di(dodecylthiomethyl)-6-methylphenol; and / or The phosphite antioxidant is selected from one or more of the following: tri(nonylphenyl) phosphite, diphenyl isodecyl phosphite, diphenyl diisodecyl phosphite, triphenyl phosphite, diisopropanol ether diphenyl phosphite, tris(mixed 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phosphite), triisodecyl phosphite, and pentaerythritol diisodecyl diphosphite; and / or The ultraviolet absorber is selected from the reaction products of 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole, 3-benzotriazole-5-tert-butyl-4-hydroxyphenyl propionate and C7-C9 alcohol, 3-benzotriazole-5-tert-butyl-4-hydroxyphenyl propionate and PEG-300, and 2-[4-[2-hydroxy-3-tetrazoloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis( A mixture of 2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-[2-hydroxy-3-dodecoxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, one or more of bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

11. The raw rubber composition according to any one of claims 6-10, wherein, The amount of the anti-aging agent composition is 0.1-1% based on the total weight of the raw rubber.

12. The raw rubber composition according to any one of claims 6-10, wherein, The raw rubber is natural rubber or raw rubber synthesized by solution polymerization.

13. The raw rubber composition according to any one of claims 6-10, wherein, The raw rubber is one or more of polybutadiene, polyisoprene, polybutadiene-styrene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-butadiene block copolymer, and hydrogenated styrene-isoprene block copolymer.

14. A rubber article formed from the raw rubber composition of any one of claims 1-13.

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