An antioxidant composition, a rubber composition and its uses

Abstract

This invention belongs to the field of rubber materials and relates to an antioxidant composition, a rubber composition, and its uses. The antioxidant composition of this invention comprises component A and component B; wherein component A is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, and component B is selected from one or two of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline polymers. The antioxidant composition of this invention containing 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine can significantly improve the thermo-oxidative aging resistance and adhesive properties of rubber compositions, and extend the service life of rubber products.

Description

Technical Field

[0001] This invention belongs to the field of rubber materials, specifically relating to an antioxidant composition, a rubber composition, and its uses. Background Technology

[0002] Tires are an important component of modern automobiles. Because they are often used under high-speed and high-load conditions, and are subjected to the impact and bumps caused by uneven road surfaces, as well as adverse factors such as high temperature, salt or corrosive water, their performance directly affects the economy of automobile use and driving safety.

[0003] The belt layer and the carcass are two important components of a tire. (1) The belt layer is composed of a rubber composition and a metal skeleton material. During tire operation, the belt layer is subjected to high shear stress, so the belt layer rubber is required to have high tensile strength and fatigue resistance. At the same time, because the belt layer is located in the middle of the tire body, heat is not easily dissipated, so the belt layer rubber composition must have excellent resistance to thermo-oxidative aging. In addition, because rubber and steel cord differ greatly in modulus, polarity, etc., the belt layer rubber composition must also have excellent adhesion to metal surfaces. (2) The carcass is composed of a rubber composition and a skeleton material. During tire operation, the carcass bears the tension formed by high loads. Therefore, in addition to having high tensile strength, the carcass rubber must also have excellent adhesion to metal or fiber skeleton materials to ensure the high load and service durability of the tire. At the same time, the tire generates heat during operation, causing the components to heat up, so the carcass rubber composition should also have good resistance to thermo-oxidative aging. Therefore, both the belt layer and the carcass of a tire are required to have excellent adhesion and resistance to heat and oxygen aging.

[0004] In the prior art, quinoline and p-phenylenediamine antioxidants have long been used in tire rubber compositions, particularly in belt layer and carcass rubber compositions. Examples include 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMQ), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), and N,N'-xylyl-p-phenylenediamine (DTPD). While p-phenylenediamine antioxidants currently used in the steel cord rubber compositions of tire carcasses and belt layers show good effects on ozone resistance and long-term performance, they perform poorly in terms of resistance to thermo-oxidative aging and adhesive properties.

[0005] Therefore, there is an urgent need to develop an antioxidant that can improve the resistance to thermo-oxidative aging and the adhesive properties of rubber compositions. Summary of the Invention

[0006] To address the problems existing in the prior art, the 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and antioxidant composition disclosed in this invention has better adhesion, better long-term resistance to thermo-oxidative aging and resistance to damp heat aging, and the rubber composition of this invention has high safety when applied to tire carcasses or belt layers.

[0007] Specifically, the present invention provides an antioxidant composition comprising component A and component B; wherein component A is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, and component B is selected from one or two of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline polymer.

[0008] In one or more embodiments, the mass ratio of component A to component B in the antioxidant composition is 1:(0.1 to 6).

[0009] In one or more embodiments, the antioxidant composition comprises 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine in a mass ratio of 1:(0.16-6).

[0010] In one or more embodiments, the antioxidant composition comprises a polymer of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and 2,2,4-trimethyl-1,2-dihydroquinoline in a mass ratio of 1:(0.33-3).

[0011] In one or more embodiments, the antioxidant composition comprises 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline polymer in a mass ratio of 1:(0.1-3):(0.1-3).

[0012] The present invention provides a rubber composition comprising 100 parts by weight of a diene elastomer and 0.1-7 parts by weight of an antioxidant; wherein the antioxidant is an antioxidant composition described in any embodiment herein or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine.

[0013] In one or more embodiments, the raw materials of the rubber composition include 2.5-3.5 parts by weight of an antioxidant.

[0014] In one or more embodiments, the diene elastomer is selected from one or more of natural rubber, butadiene rubber, styrene-butadiene rubber, and polyisoprene.

[0015] In one or more embodiments, the diene elastomer is natural rubber.

[0016] In one or more embodiments, the raw materials of the rubber composition further include 10-70 parts by weight of reinforcing filler.

[0017] In one or more embodiments, the reinforcing filler is carbon black.

[0018] In one or more embodiments, the raw materials of the rubber composition further include 1-6 parts by weight of a crosslinking agent.

[0019] In one or more embodiments, the crosslinking agent is sulfur.

[0020] In one or more embodiments, the raw materials of the rubber composition further include 1-10 parts by weight of an activator.

[0021] In one or more embodiments, the activator is zinc oxide.

[0022] In one or more embodiments, the raw materials of the rubber composition further include 0.1-3 parts by weight of cobalt salt.

[0023] In one or more embodiments, the raw materials of the rubber composition further include 0.1-3 parts by weight of a tackifying resin.

[0024] In one or more embodiments, the raw materials of the rubber composition further include 0.1-6 parts by weight of a rubber adhesive.

[0025] In one or more embodiments, the raw materials of the rubber composition further include 0.1-3 parts by weight of an accelerator.

[0026] In one or more embodiments, the promoter is N,N-dicyclohexyl-2-benzothiazole sulfenamide.

[0027] The present invention provides a rubber article comprising the rubber composition described in any embodiment herein; preferably, the rubber article is a tire.

[0028] The present invention provides a method for improving the thermo-oxidative aging resistance and / or adhesive properties of a rubber composition, the method comprising adding an antioxidant composition as described in any embodiment herein or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine to the raw material of the rubber composition.

[0029] This invention provides the use of the antioxidant composition described in any embodiment herein or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine in improving the thermo-oxidative aging resistance and / or adhesive properties of rubber compositions or rubber articles. Detailed Implementation

[0030] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0031] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0032] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0033] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0034] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0035] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0036] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0037] The structural formula of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine (hereinafter referred to as compound I) is as follows:

[0038] The present invention provides an antioxidant composition comprising component A and component B; wherein component A is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, and component B is selected from one or two of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline polymer.

[0039] In some embodiments, the antioxidant composition is composition A, composition B, or composition C; composition A is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD); composition B is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMQ); composition C is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline polymer.

[0040] In the antioxidant composition of the present invention, the mass ratio of component A to component B is 1:(0.1-6), for example 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6.

[0041] In some embodiments, the antioxidant composition is composition A, where the mass ratio of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine to N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine can be 1:(0.16-6), for example 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6.

[0042] In some embodiments, the antioxidant composition is composition B, in which the mass ratio of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine to the 2,2,4-trimethyl-1,2-dihydroquinoline polymer can be 1:(0.33-3), for example 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3.

[0043] In some embodiments, the antioxidant composition is composition C, where the mass ratio of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline polymer can be 1:(0.1-3):(0.1-3), for example 1:0.1:0.1, 1:0.5:0.5, 1:0.5:1, 1:1:0.5, 1:1:1, 1:1.5:1, 1:1:1.5, 1:1.5:1.5, 1:2:1.5, 1:1.5:2, 1:2:2, 1:1:2, 1:2:1, 1:3:1, 1:1:3, preferably 1:(0.5-2):(0.5-2).

[0044] The raw materials of the rubber composition of the present invention include a diene elastomer and an antioxidant, wherein the antioxidant is the antioxidant composition of the present invention or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine. Unless otherwise specified herein, the mass parts of other components in the raw materials of the rubber composition are calculated based on 100 parts by mass of the diene elastomer. Based on 100 parts by mass of the diene elastomer, the amount of antioxidant can be 0.1-7 parts by mass, preferably 1-5 parts by mass, more preferably 2.5-3.5 parts by mass, for example 2.5 parts by mass, 2.6 parts by mass, 2.7 parts by mass, 2.8 parts by mass, 2.9 parts by mass, 3.0 parts by mass, 3.1 parts by mass, 3.2 parts by mass, 3.3 parts by mass, 3.4 parts by mass, and 3.5 parts by mass.

[0045] In some embodiments, the rubber composition of the present invention does not contain any antioxidants other than the compound of formula I. In this case, the amount of the compound of formula I in the raw materials of the rubber composition can be 0.1-7 parts by weight, preferably 1-5 parts by weight, more preferably 2.5-3.5 parts by weight, for example 2.5 parts by weight, 2.6 parts by weight, 2.7 parts by weight, 2.8 parts by weight, 2.9 parts by weight, 3.0 parts by weight, 3.1 parts by weight, 3.2 parts by weight, 3.3 parts by weight, 3.4 parts by weight, and 3.5 parts by weight.

[0046] In some embodiments, the antioxidant contained in the rubber composition of the present invention is composition A, in which case the total amount of both the compound of formula I and 6PPD can be 0.1-7 parts by mass, preferably 1-5 parts by mass, more preferably 2.5-3.5 parts by mass, for example 2.5 parts by mass, 2.6 parts by mass, 2.7 parts by mass, 2.8 parts by mass, 2.9 parts by mass, 3.0 parts by mass, 3.1 parts by mass, 3.2 parts by mass, 3.3 parts by mass, 3.4 parts by mass, and 3.5 parts by mass.

[0047] In some embodiments, the antioxidant contained in the rubber composition of the present invention is composition B, in which case the total amount of both the compound of formula I and TMQ can be 0.1-7 parts by mass, preferably 1-5 parts by mass, more preferably 2.5-3.5 parts by mass, for example 2.5 parts by mass, 2.6 parts by mass, 2.7 parts by mass, 2.8 parts by mass, 2.9 parts by mass, 3.0 parts by mass, 3.1 parts by mass, 3.2 parts by mass, 3.3 parts by mass, 3.4 parts by mass, and 3.5 parts by mass.

[0048] In some embodiments, the antioxidant contained in the rubber composition of the present invention is composition C, in which case the total amount of the compound of formula I, 6PPD and TMQ can be 0.1-7 parts by mass, preferably 1-5 parts by mass, more preferably 2.5-3.5 parts by mass, for example 2.5 parts by mass, 2.6 parts by mass, 2.7 parts by mass, 2.8 parts by mass, 2.9 parts by mass, 3.0 parts by mass, 3.1 parts by mass, 3.2 parts by mass, 3.3 parts by mass, 3.4 parts by mass, and 3.5 parts by mass.

[0049] In this document, diene elastomers refer to elastomers whose monomers comprise dienes (such as butadiene or isoprene). Diene elastomers suitable for use in this invention can be various diene elastomers known in the art, including but not limited to one or more selected from natural rubber (NR), butadiene rubber (BR), isoprene rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), polyisoprene, isoprene / butadiene copolymers, isoprene / styrene copolymers, and isoprene / butadiene / styrene copolymers. In some preferred embodiments, the diene elastomer comprises or is composed of natural rubber. Examples of natural rubber include SCR5.

[0050] The raw materials for the rubber composition of the present invention may further include reinforcing fillers. The amount of reinforcing filler in the raw materials of the rubber composition of the present invention may be 10-70 parts by weight, for example 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, or 70 parts by weight. The reinforcing fillers suitable for the present invention may be conventional reinforcing fillers used in rubber compositions, including but not limited to one or more selected from carbon black, silica, titanium dioxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, clay, and talc. In some embodiments, the reinforcing filler comprises carbon black. Examples of carbon black include carbon black N326.

[0051] The raw materials of the rubber composition of the present invention may further include a crosslinking agent, such as sulfur. The sulfur is preferably insoluble sulfur. In the raw materials of the rubber composition of the present invention, the amount of sulfur can be 1-6 parts by weight, preferably 4-6 parts by weight, for example 4.5 parts by weight, 4.6 parts by weight, or 5 parts by weight.

[0052] The raw materials for the rubber composition of the present invention may also include other components that can be used in the rubber composition, including but not limited to one or more selected from activators, cobalt salts, tackifying resins, rubber adhesives and accelerators.

[0053] Activators can accelerate vulcanization, improve the thermal conductivity, abrasion resistance, and tear resistance of rubber. The raw materials of the rubber composition of the present invention preferably include activators. Examples of activators include ZnO. In the raw materials of the rubber composition of the present invention, the amount of activator can be 1-10 parts by weight, for example, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, or 10 parts by weight. In some preferred embodiments, the activator includes ZnO, or the activator is ZnO. In some preferred embodiments, the amount of ZnO in the raw materials of the rubber composition of the present invention is 7-9 parts by weight, for example, 8 parts by weight.

[0054] Cobalt salts can effectively promote the adhesion of rubber to steel cords. When used as a tire belt layer compound, the raw materials of the rubber composition of the present invention preferably include cobalt salts. Cobalt salts that can be used in the present invention include, but are not limited to, cobalt borylate and cobalt neodecanoate. In the raw materials of the rubber composition of the present invention, the amount of cobalt salt can be 0.1-3 parts by weight, preferably 0.1-1 parts by weight, for example, 0.2 parts by weight, 0.5 parts by weight, or 0.8 parts by weight.

[0055] The tackifying resin is used to enhance the adhesion between the rubber and the steel cord. When used as a tire belt layer compound, the raw materials of the rubber composition of the present invention preferably include a tackifying resin. Suitable tackifying resins include resorcinol donors, such as resorcinol-80. The mass fraction of resorcinol-80 is ≥80%. In the raw materials of the rubber composition of the present invention, the amount of tackifying resin can be 0.1-3 parts by mass, preferably 0.5-2.5 parts by mass, for example 1 part by mass, 1.5 parts by mass, 1.9 parts by mass, or 2 parts by mass.

[0056] The rubber adhesive can be a methylene donor (e.g., hexamethoxymethyl melamine) used in conjunction with a tackifying resin to ensure adequate bonding between the rubber and reinforcing materials such as steel wire. When used as a tire belt layer compound, the raw materials of the rubber composition of the present invention preferably include a rubber adhesive. Available rubber adhesives include those with hexamethoxymethyl melamine (HMMM) as the active ingredient, such as rubber adhesive RA. Rubber adhesive RA consists of HMMM and an inorganic carrier. Examples of rubber adhesive RA include rubber adhesive RA-65. The mass fraction of HMMM in rubber adhesive RA-65 is ≥65%. In the raw materials of the rubber composition of the present invention, the amount of rubber adhesive can be 0.1-6 parts by mass, preferably 4-6 parts by mass, for example, 5 parts by mass.

[0057] The accelerator is typically a vulcanization accelerator, and may be one or more selected from sulfonamide vulcanization accelerators, thiazole vulcanization accelerators, thiuram vulcanization accelerators, guanidine vulcanization accelerators, dithiocarbamate vulcanization accelerators, aldehyde-amine vulcanization accelerators, aldehyde-amine vulcanization accelerators, imidazoline vulcanization accelerators, and xanthic acid vulcanization accelerators. In the raw materials of the rubber composition of the present invention, the amount of accelerator may be 0.1-3 parts by weight, preferably 1-2 parts by weight, for example 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, or 1.8 parts by weight. In some preferred embodiments, the accelerator is accelerator DZ (N,N'-dicyclohexyl-2-benzothiazole sulfinamide).

[0058] When the rubber composition is used as a tire belt layer compound, the rubber composition of the present invention preferably comprises an adhesive system consisting of a resorcinol donor (e.g., resorcinol), a methylene donor (e.g., HMMM), and carbon black, which can effectively improve the adhesion between the rubber and the metal. The amounts of the resorcinol donor, the methylene donor, and the carbon black can be as described in any embodiment herein.

[0059] In some preferred embodiments, the raw materials of the rubber composition of the present invention include: 100 parts by weight of diene elastomer, 1-6 parts by weight (e.g., 4.6 parts by weight) of sulfur, 0.1-7 parts by weight (e.g., 3 parts by weight) of compound of formula I or the antioxidant composition of the present invention, 10-70 parts by weight (e.g., 50 parts by weight) of carbon black, 1-10 parts by weight (e.g., 8 parts by weight) of ZnO, 0.1-3 parts by weight (e.g., 0.5 parts by weight) of cobalt salt, 0.1-3 parts by weight (e.g., 1.9 parts by weight) of tackifying resin, 0.1-6 parts by weight (e.g., 5 parts by weight) of rubber adhesive and 0.1-3 parts by weight (e.g., 1.4 parts by weight) of accelerator, or a mixture of the above components.

[0060] The uncured rubber of the present invention can be prepared using conventional rubber mixing methods, such as a two-stage mixing process: a first-stage thermomechanical (e.g., internal mixer) mixing, in which rubber composition raw materials other than crosslinking agents, rubber adhesives and accelerators are mixed, and the entire mixture is kneaded until a maximum temperature between 110°C and 190°C is reached to obtain a first-stage rubber; a second-stage thermomechanical (e.g., open mill) mixing, in which the first-stage rubber is cooled to below 100°C, crosslinking agents, rubber adhesives and accelerators are added, and the first-stage rubber is kneaded with the crosslinking agents, rubber adhesives and accelerators until a maximum temperature below 110°C is reached to obtain a second-stage rubber, i.e., uncured rubber.

[0061] Uncured rubber is vulcanized (cured) to obtain vulcanized rubber. The vulcanization temperature is usually 130℃-200℃, such as 140-160℃ or 150±5℃; the vulcanization time depends on the vulcanization temperature, vulcanization system and vulcanization kinetics, and is usually 15-60 minutes, such as 20-40 minutes or 30±5 minutes.

[0062] Compared to rubber compositions using antioxidant 6PPD, the rubber compositions of the present invention, using 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine or antioxidant compositions (Composition A, Composition B, and Composition C) as antioxidants, when used in rubber products, such as tires, especially tire belt layers and carcasses, can give the rubber products better resistance to thermo-oxidative aging and better adhesion between rubber and steel wires. Therefore, the present invention also provides a rubber product containing the rubber composition described herein. The rubber product can be a tire, rubber shoe, sealing strip, sound insulation plate, vibration damping pad, etc. The rubber product is preferably a tire, such as a tire belt layer and carcass.

[0063] This invention also provides the use of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine or the antioxidant composition of this invention in improving the thermo-oxidative aging resistance and / or adhesive properties of rubber compositions or rubber articles, and methods for improving the thermo-oxidative aging resistance and / or adhesive properties of rubber compositions or rubber articles. Preferably, the use or method of this invention comprises adding 0.1-7 parts by weight of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine or the antioxidant composition of this invention to a raw material of a rubber composition containing 100 parts by weight of a diene elastomer. In the use or method of this invention, the amount of 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine or the antioxidant composition of this invention and the raw material composition of the rubber composition are preferably as described in any embodiment herein.

[0064] Compared with the prior art, the present invention has the following beneficial effects: the rubber composition disclosed in the present invention containing 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine or the antioxidant composition of the present invention has better adhesion, better long-term resistance to thermo-oxidative aging and resistance to damp heat aging, and the rubber composition of the present invention has higher safety when applied to tire carcass or belt layer.

[0065] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art, unless otherwise stated. The raw material compounds in the embodiments are all commercially available.

[0066] Preparation of Compound I

[0067] (1) Add 400g (3mol) of aniline and 182g (0.5mol) of 25wt% tetramethylammonium hydroxide (TMAH) aqueous solution to a 1L four-necked flask, stir and heat to 40-55℃, then distill under reduced pressure to dehydrate, allowing TMAH to form a salt with aniline. During this process, the reaction solution gradually changes from yellow to dark red. Gradually heat to 72℃, and when the fraction reaches 46mL, add 63.5g (0.5mol) of 3-nitropyridine dropwise while distilling under reduced pressure (-0.098MPa) at 72℃. The addition is carried out for 3 hours, and after the addition is complete, keep warm for 1 hour. LC monitoring detects the presence of 3-nitropyridine. The pyridine reaction was completed, yielding a condensate. The condensate was transferred to a 500 mL stainless steel reactor, and 100 g of deionized water and 80 g of nickel catalyst were added. The reactor was purged with hydrogen three times, heated to 75 °C, and hydrogen was introduced at 1.5 MPa for hydrogenation reduction. LC monitoring showed that the nitro and nitroso compounds were completely reduced. The reactor was then filtered and separated. The organic phase was washed with water and distilled under reduced pressure (-0.1 MPa, 160 °C) to remove aniline and light byproducts. Finally, 47.4 g of the reduced product was distilled off, cooled, and solidified into a yellow solid with a yield of approximately 51%. GC analysis showed a content >99%.

[0068] (2) 37.1 g (0.2 mol) of reduction product, 280.6 g (2.8 mol) of 4-methyl-2-pentanone and 0.5 g of Pt / C catalyst were added to the reactor, purged with hydrogen three times, heated to 70 °C, and hydrogen was introduced to 1.5 MPa for reaction. The reaction was stopped when the content of reduction product was <0.1% by GC detection. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation (-0.1 MPa, 180 °C) to obtain 53.3 g of compound I (yield of about 99%). The content was >98% by GC detection. After cooling and solidification, it was a light brown solid.

[0069] The NMR results of compound I were as follows: 1H NMR: δ 8.86 (1H), 7.54 (2H), 7.44 (1H), 7.35 (1H), 7.31 (2H), 6.93 (1H), 5.53 (2H), 3.33 (1H), 1.90 (2H), 1.62 (1H), 1.24 (3H), 0.89 (6H).

[0070] The sources and specifications of the raw materials used in the examples are as follows:

[0071] Natural rubber: Xishuangbanna Sinochem Rubber Co., Ltd., SCR5;

[0072] Carbon black: Shanghai Cabot Carbon Black Co., Ltd., N326;

[0073] Antioxidant 6PPD: Sheng'ao Chemical Technology Co., Ltd.;

[0074] Anti-aging agent TMQ: Sheng'ao Chemical Technology Co., Ltd.;

[0075] Zinc oxide: Yonghua Chemical Technology (Jiangsu) Co., Ltd.;

[0076] Cobalt neodecanoate: Zhenjiang Mait New Material Chemical Co., Ltd.;

[0077] Resorcinol-80: Wenzhou Grey Chemical Co., Ltd.;

[0078] Rubber adhesive: Shandong Ruiqi Chemical Co., Ltd., RA-65;

[0079] Insoluble sulfur: Sunon Chemical Technology Co., Ltd., HD OT20;

[0080] Accelerator DZ: Weilin New Materials Technology Co., Ltd.

[0081] Examples 1-4 and Comparative Examples 1-2

[0082] According to the formulations shown in Table 1, the rubber compositions and vulcanized rubbers of Examples 1-4 and Comparative Examples 1-2 were prepared using the following process:

[0083] (1) Add diene elastomer (natural rubber NR) to the internal mixer and knead it. Then add reinforcing filler (carbon black N326), additive (ZnO) and antioxidant (6PPD, TMQ, compound I) in batches and continue kneading until the mixture is uniform. During kneading, the temperature is controlled between 150℃ and 160℃ to obtain a section of rubber.

[0084] (2) Cool the first stage of the rubber to below 100°C, then add the crosslinking system (insoluble sulfur, accelerator and rubber adhesive), knead the whole mixture, and control the temperature not to exceed 110°C during kneading to obtain the second stage of the rubber, i.e. the rubber composition.

[0085] (3) The two-stage rubber is vulcanized at a temperature of 151°C for 30 minutes to obtain vulcanized rubber.

[0086] Table 1: Formulations of the rubber compositions of Examples 1-4 and Comparative Examples 1-2 (unit: parts by mass)

[0087] Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 SCR5 100 100 100 100 100 100 Carbon Black N326 50 50 50 50 50 50 Anti-aging agent 6PPD 3.0 2.0 0 1.0 0 2.0 Formula I compound 0 0 3.0 1.0 2.0 1.0 Anti-aging agent TMQ 0 1.0 0 1.0 1.0 0 Zinc oxide 8.0 8.0 8.0 8.0 8.0 8.0 Cobalt neodecanoate 0.5 0.5 0.5 0.5 0.5 0.5 Resorcinol-80 1.9 1.9 1.9 1.9 1.9 1.9 RA-65 5.0 5.0 5.0 5.0 5.0 5.0 Insoluble sulfur 4.6 4.6 4.6 4.6 4.6 4.6 Accelerator DZ 1.4 1.4 1.4 1.4 1.4 1.4

[0088] Test Example 1: Mechanical Properties

[0089] The elongation at break, tensile strength, tensile strength, and tear strength of the vulcanized rubbers prepared in Examples 1-4 and Comparative Examples 1-2 before and after thermo-oxidative aging were tested according to the following standards. The test results are shown in Table 2. Wherein, MA100 represents the tensile strength of the vulcanized rubber at an elongation of 100%.

[0090] Tensile strength, elongation at break and tensile strength: GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0091] Tear strength: GB / T 529-2008 Determination of tear strength of vulcanized rubber (trouser-shaped, right-angled and crescent-shaped specimens).

[0092] Thermo-oxidative aging test: GB / T 3512-2014 Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air, aging conditions are 100℃×48h.

[0093] Table 2: Mechanical properties of vulcanized rubbers obtained in Examples 1-4 and Comparative Examples 1-2

[0094]

[0095] As can be seen from Table 2, the physical properties of the vulcanized rubbers prepared in Examples 1-4 before aging are similar to those of the vulcanized rubbers prepared in Comparative Examples 1-2; however, after thermo-oxidative aging at 100℃ for 48h, the elongation at break, tensile strength, and tear strength of the vulcanized rubbers prepared in Examples 1-4 are all superior to those of the vulcanized rubbers prepared in Comparative Examples 1-2.

[0096] Test Example 2: Steel Wire Adhesion Performance

[0097] The steel wire bonding properties of the vulcanized rubbers prepared in Examples 1-4 and Comparative Examples 1-2 before and after thermo-oxidative aging, before and after damp heat aging, and before and after salt water aging were tested according to the following standards. The test results are shown in Table 3.

[0098] Adhesion strength: GB / T 16586-1996 Determination of adhesion strength between vulcanized rubber and steel cord.

[0099] Thermo-oxidative aging test: GB / T 3512-2014 Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air, aging conditions are 100℃×7d.

[0100] Damp heat aging test: GB / T 15905-1995 Damp heat aging test method for vulcanized rubber, aging conditions are 85℃×95% (relative humidity)×7d.

[0101] Salt water aging experiment: The aging conditions were 10wt% NaCl solution × 7d.

[0102] Table 3: Steel wire bonding properties of vulcanized rubbers obtained in Examples 1-4 and Comparative Examples 1-2

[0103] Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Before aging, N 912 908 903 911 916 906 Thermo-oxidative aging, N 723 718 850 789 798 823 Moist heat aging, N 712 705 841 774 788 810 Salt water aging, N 549 548 650 601 613 626

[0104] As can be seen from Table 3, the steel wire bonding samples of vulcanized rubber prepared in Examples 1-4 showed good bonding performance before aging; after aging under certain conditions of heat and oxygen, humid heat or salt water, the bonding performance of the steel wire bonding samples of vulcanized rubber prepared in Examples 1-4 was significantly better than that of the steel wire bonding samples of vulcanized rubber prepared in Comparative Examples 1-2.

Claims

1. An antioxidant composition, characterized in that, The antioxidant composition comprises component A and component B; wherein component A is 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine, and component B is selected from one or two of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline polymer.

2. The antioxidant composition according to claim 1, characterized in that, In the antioxidant composition, the mass ratio of component A to component B is 1:(0.1-6); preferably, the antioxidant composition comprises 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine in a mass ratio of 1:(0.16-6), or the antioxidant composition comprises 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine in a mass ratio of 1:(0.33-3). The antioxidant composition comprises 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine and 2,2,4-trimethyl-1,2-dihydroquinoline polymer in a mass ratio of 1:(0.1-3):(0.1-3).

3. A rubber composition, characterized in that, The raw materials of the rubber composition include 100 parts by weight of diene elastomer and 0.1-7 parts by weight of antioxidant; the antioxidant is the antioxidant composition according to claim 1 or 2 or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine.

4. The rubber composition according to claim 3, characterized in that, The raw materials of the rubber composition include 2.5-3.5 parts by weight of antioxidant.

5. The rubber composition according to claim 3, characterized in that, The rubber composition has one or more of the following characteristics: The diene elastomer is selected from one or more of natural rubber, butadiene rubber, styrene-butadiene rubber, and polyisoprene; the diene elastomer is preferably natural rubber. The raw materials of the rubber composition also include 10-70 parts by weight of reinforcing filler; the reinforcing filler is preferably carbon black; The raw materials of the rubber composition also include 1-6 parts by weight of a crosslinking agent; the crosslinking agent is preferably sulfur; The raw materials of the rubber composition also include 1-10 parts by weight of an activator; the activator is preferably zinc oxide; The raw materials of the rubber composition also include 0.1-3 parts by weight of cobalt salt; The raw materials of the rubber composition also include 0.1-3 parts by weight of tackifying resin; The raw materials of the rubber composition also include 0.1-6 parts by weight of rubber adhesive; The raw materials of the rubber composition also include 0.1-3 parts by weight of an accelerator; the accelerator is preferably N,N-dicyclohexyl-2-benzothiazole sulfenamide.

6. A rubber product, characterized in that, The rubber article comprises the rubber composition according to any one of claims 3-5; preferably, the rubber article is a tire.

7. A method for improving the thermo-oxidative aging resistance and / or adhesive properties of a rubber composition, characterized in that, The method includes adding the antioxidant composition of claim 1 or 2 or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine to the raw material of the rubber composition.

8. The method as described in claim 7, characterized in that, The raw materials of the rubber composition include 100 parts by weight of diene elastomer and 0.1-7 parts by weight of the antioxidant composition according to claim 1 or 2 or 5-[(2,4-dimethylbutyl)amino]-2-(phenylamino)pyridine.

9. The method as described in claim 8, characterized in that, The raw materials of the rubber composition include 2.5-3.5 parts by weight of antioxidant.

10. The method as described in claim 8, characterized in that, The method has one or more of the following characteristics: The diene elastomer is selected from one or more of natural rubber, butadiene rubber, styrene-butadiene rubber, and polyisoprene; the diene elastomer is preferably natural rubber. The raw materials of the rubber composition also include 10-70 parts by weight of reinforcing filler; the reinforcing filler is preferably carbon black; The raw materials of the rubber composition also include 1-6 parts by weight of a crosslinking agent; the crosslinking agent is preferably sulfur; The raw materials of the rubber composition also include 1-10 parts by weight of an activator; the activator is preferably zinc oxide; The raw materials of the rubber composition also include 0.1-3 parts by weight of cobalt salt; The raw materials of the rubber composition also include 0.1-3 parts by weight of tackifying resin; The raw materials of the rubber composition also include 0.1-6 parts by weight of rubber adhesive; The raw materials of the rubber composition also include 0.1-3 parts by weight of an accelerator; the accelerator is preferably N,N-dicyclohexyl-2-benzothiazole sulfenamide.

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