Fatigue and aging resistant rubber composition and application thereof

Abstract

The present invention provides a fatigue aging resistant rubber composition and uses thereof, the raw materials of the rubber composition comprise 100 parts by mass of a diene elastomer and 1-3 parts by mass of a compound represented by a formula A, and the compound represented by the formula A is described in the specification. The compound in the formula A can significantly improve the fatigue aging resistance of the rubber composition and prolong the service life of a rubber product.

Description

Technical Field

[0001] The invention belongs to the field of rubber materials and relates to a fatigue-resistant and aging-resistant rubber composition and application thereof. Background Art

[0002] Fatigue aging refers to the damage or irreversible changes in structure and performance of rubber products under cyclic stress and deformation. Tires, transmission belts, conveyor belts, rubber springs, and rubber shock absorbers will all experience fatigue aging. Rubber fatigue is caused by cyclic mechanical force, but this phenomenon does not exist in isolation. During the entire fatigue process, thermal oxygen aging and ozone aging are also carried out, which is the result of the combined action of multiple factors. The main external factors are: ambient temperature, oxygen content, ozone concentration, strain amplitude and frequency. Fatigue aging will accelerate the damage of rubber products and shorten the service life of products. The fatigue aging resistance of rubber usually refers to the number of cyclic stress (deformation) experienced by the sample when it is damaged. The fatigue resistance of rubber is generally evaluated by flexion-crack test and dynamic tensile fatigue test. The former observes the occurrence of cracks in the sample and the growth of cracks, while the latter records the number of fatigue times when the sample breaks.

[0003] Paraphenylenediamine antioxidants, such as antioxidant 6PPD (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine), etc., have good resistance to ozone aging and good resistance to fatigue aging, and are therefore widely used in the formulation of automobile tire products.

[0004] However, when the external environment and conditions of rubber products become extremely harsh or a longer service life is sought, technicians often simply increase the amount of antioxidants to meet performance requirements. However, p-phenylenediamine antioxidants have serious problems of migration and discoloration. Increasing the amount of antioxidants will inevitably further amplify the problems of tire appearance quality and environmental pollution, and will also cause an increase in corporate costs. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a rubber composition containing a compound of formula A, a method for improving the fatigue aging resistance of the rubber composition, and the use of the compound of formula A in improving the fatigue aging resistance of the rubber composition. The compound of formula A can significantly improve the fatigue aging resistance (including flex-crack aging resistance and dynamic tensile fatigue resistance) of the rubber composition and extend the service life of the rubber product.

[0006] Specifically, one aspect of the present invention provides a rubber composition, the raw materials of the rubber composition comprising 100 parts by mass of a diene elastomer and 1-3 parts by mass, for example 1.5-2 parts by mass, of a compound of formula A:

[0007]

[0008] In formula A, R1, R2 and R3 are each independently selected from C1-C8 alkyl groups.

[0009] In one or more embodiments, the raw materials of the rubber composition include two or more compounds of formula A.

[0010] In one or more embodiments, in formula A, R1 and R2 are each independently selected from C1-C3 alkyl, preferably each independently selected from methyl and ethyl.

[0011] In one or more embodiments, in formula A, R3 is selected from C3-C8 alkyl, preferably selected from C3-C6 alkyl, for example selected from C4-C6 alkyl.

[0012] In one or more embodiments, the raw materials of the rubber composition include one or more compounds selected from the group consisting of compounds of formula I, compounds of formula II, compounds of formula IV, compounds of formula VI, compounds of formula VIII, compounds of formula X, compounds of formula XII, and compounds of formula XIV:

[0013]

[0014]

[0015] In one or more embodiments, the raw materials of the rubber composition include two or more compounds selected from the group consisting of compounds of formula I, compounds of formula II, compounds of formula IV, compounds of formula VI, compounds of formula VIII, compounds of formula X, compounds of formula XII, and compounds of formula XIV.

[0016] In one or more embodiments, the raw materials of the rubber composition include two compounds selected from the group consisting of compounds of formula I, compounds of formula II, compounds of formula IV, compounds of formula VI, compounds of formula VIII, compounds of formula X, compounds of formula XII, and compounds of formula XIV.

[0017] In one or more embodiments, the raw materials of the rubber composition include a compound of formula I and a compound of formula II, or a compound of formula IV and a compound of formula VI, or a compound of formula VIII and a compound of formula X, or a compound of formula XII and a compound of formula XIV.

[0018] In one or more embodiments, in the raw materials of the rubber composition, the total amount of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1-3 parts by mass, for example, 1.5-2 parts by mass.

[0019] In one or more embodiments, in the raw materials of the rubber composition, the mass ratio of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1:2 to 2:1, for example, 1:1.5 to 1.5:1.

[0020] In one or more embodiments, the diene elastomer comprises natural rubber and butadiene rubber in a mass ratio ranging from 1:2 to 2:1.

[0021] In one or more embodiments, the raw materials of the rubber composition further include 30-70 parts by mass of a reinforcing filler; the reinforcing filler is preferably carbon black.

[0022] In one or more embodiments, the raw materials of the rubber composition further include 0.5-3 parts by mass of sulfur.

[0023] In one or more embodiments, the raw materials of the rubber composition further include 1-10 parts by mass of an active agent; preferably, the active agent is zinc oxide.

[0024] In one or more embodiments, the raw material of the rubber composition further includes 2-15 parts by mass of a softener.

[0025] In one or more embodiments, the raw materials of the rubber composition further include 0.2-2 parts by mass of an accelerator; the accelerator is preferably N-tert-butyl-2-benzothiazolesulfenamide.

[0026] Another aspect of the present invention provides a rubber product, wherein the rubber product comprises the rubber composition described in any embodiment of the present invention.

[0027] In one or more embodiments, the rubber article is a tire.

[0028] Another aspect of the present invention provides a method for improving fatigue aging resistance of a rubber composition, the method comprising: adding 1 to 3 parts by mass, for example 1.5 to 2 parts by mass, of a compound of formula A to the raw materials of the rubber composition based on 100 parts by mass of the diene elastomer contained in the raw materials of the rubber composition:

[0029]

[0030] In formula A, R1, R2 and R3 are each independently selected from C1-C8 alkyl groups.

[0031] In one or more embodiments, in formula A, R1 and R2 are each independently selected from C1-C3 alkyl, preferably each independently selected from methyl and ethyl;

[0032] In one or more embodiments, in formula A, R3 is selected from C3-C8 alkyl, preferably selected from C3-C6 alkyl, for example selected from C4-C6 alkyl.

[0033] In one or more embodiments, the method includes adding two or more compounds of formula A to the raw materials of the rubber composition.

[0034] In one or more embodiments, the method comprises: adding one or more compounds selected from the group consisting of a compound of formula I, a compound of formula II, a compound of formula IV, a compound of formula VI, a compound of formula VIII, a compound of formula X, a compound of formula XII, and a compound of formula XIV to the raw materials of the rubber composition:

[0035]

[0036] In one or more embodiments, the method includes: adding two or more compounds selected from the group consisting of compounds of formula I, compounds of formula II, compounds of formula IV, compounds of formula VI, compounds of formula VIII, compounds of formula X, compounds of formula XII, and compounds of formula XIV to the raw materials of the rubber composition.

[0037] In one or more embodiments, the method includes adding two compounds selected from the group consisting of compounds of formula I, II, IV, VI, VIII, X, XII and XIV to the raw materials of the rubber composition.

[0038] In one or more embodiments, the method includes: adding a compound of formula I and a compound of formula II, or a compound of formula IV and a compound of formula VI, or a compound of formula VIII and a compound of formula X, or a compound of formula XII and a compound of formula XIV to the raw materials of the rubber composition.

[0039] In one or more embodiments, in the raw materials of the rubber composition, the total amount of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1-3 parts by mass, for example, 1.5-2 parts by mass.

[0040] In one or more embodiments, in the raw materials of the rubber composition, the mass ratio of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1:2 to 2:1, for example, 1:1.5 to 1.5:1.

[0041] In one or more embodiments, the diene elastomer comprises natural rubber and butadiene rubber in a mass ratio ranging from 1:2 to 2:1.

[0042] In one or more embodiments, the raw materials of the rubber composition further include 30-70 parts by mass of a reinforcing filler; the reinforcing filler is preferably carbon black.

[0043] In one or more embodiments, the raw materials of the rubber composition further include 0.5-3 parts by mass of sulfur.

[0044] In one or more embodiments, the raw materials of the rubber composition further include 1-10 parts by mass of an active agent; preferably, the active agent is zinc oxide.

[0045] In one or more embodiments, the raw material of the rubber composition further includes 2-15 parts by mass of a softener.

[0046] In one or more embodiments, the raw materials of the rubber composition further include 0.2-2 parts by mass of an accelerator; the accelerator is preferably N-tert-butyl-2-benzothiazolesulfenamide. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0048] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0049] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0050] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0051] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0052] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0053] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0054] As used herein, an alkyl group refers to a linear or branched monovalent saturated hydrocarbon group, typically containing 1 to 18 carbon atoms (C1-C18 alkyl), for example, containing 1 to 8 carbon atoms (C1-C8 alkyl). Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, 1-methylpropyl, isobutyl, 1-methylbutyl, and 1,3-dimethylbutyl.

[0055] In the present invention, the compound of formula A has the following structure:

[0056]

[0057] In formula A, R1, R2 and R3 are each independently selected from C1-C8 alkyl groups.

[0058] In some embodiments, R1 is selected from C1-C4 alkyl, preferably C1-C3 alkyl, for example methyl, ethyl. R1 can be located in the ortho, meta or para position of the -NH- group.

[0059] In some embodiments, R2 is selected from C1-C4 alkyl, preferably C1-C3 alkyl, for example methyl, ethyl. R2 can be located in the ortho or meta position of the -NH-R3 group.

[0060] In some embodiments, R3 is selected from C3-C8 alkyl, preferably from C3-C6 alkyl, for example from isopropyl, 1-methylpropyl, 1-methylbutyl, 1,3-dimethylbutyl, more preferably from C4-C6 alkyl.

[0061] Examples of compounds of formula A include compounds of formula I, formula II, formula IV, formula VI, formula VIII, formula X, formula XII, and formula XIV as follows:

[0062]

[0063]

[0064] The present invention finds that the use of one or more compounds of formula A in a rubber composition, especially a tire rubber composition, can significantly improve the fatigue aging resistance of the rubber composition, and the improvement effect is better than that of the antioxidant 6PPD. Herein, the improvement of fatigue aging resistance refers to the improvement of the flex crack resistance and / or dynamic tensile fatigue resistance of the rubber composition.

[0065] The present invention also found that the use of two or more compounds of formula A exhibits a significant synergistic effect in improving the fatigue aging resistance of the rubber composition compared to the use of one compound of formula A alone. In some embodiments, the present invention uses two compounds of formula A in the rubber composition, for example, two compounds selected from the group consisting of a compound of formula I, a compound of formula II, a compound of formula IV, a compound of formula VI, a compound of formula VIII, a compound of formula X, a compound of formula XII, and a compound of formula XIV, for example, a compound of formula I and a compound of formula II, or a compound of formula IV and a compound of formula VI, or a compound of formula VIII and a compound of formula X, or a compound of formula XII and a compound of formula XIV are used in the rubber composition.

[0066] In the present invention, the compound of formula A can be prepared by a method comprising the following steps:

[0067] (1) subjecting a compound of formula B and a compound of formula C to a condensation reaction under the action of a first catalyst to obtain a condensate containing a compound of formula D and / or a compound of formula D′, and then subjecting the condensate to a reduction reaction under the action of H2 and a second catalyst to obtain a compound of formula E;

[0068]

[0069] (2) subjecting the compound of formula E to a reductive alkylation reaction with an aldehyde compound or a ketone compound represented by formula F in the presence of H2 and a third catalyst to obtain a compound of formula A;

[0070]

[0071] R1, R2, and R3 in Formula A, Formula B, Formula C, Formula D, and Formula E are as described in any embodiment herein, and R4 and R5 in Formula F are each independently selected from H and C1-C7 alkyl. Those skilled in the art can determine suitable R4 and R5 in Formula F based on R3 contained in the compound of Formula A.

[0072] The first catalyst used in step (1) can be one or more selected from alkali metal hydroxides, alkali metal alkoxides, quaternary ammonium bases, and combinations of alkali metal hydroxides and tetraalkylammonium halides. Suitable alkali metal hydroxides for the present invention include sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. Suitable alkali metal alkoxides for the present invention include sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium tert-amyl alcoholate, potassium tert-amyl alcoholate, etc. Quaternary ammonium bases are a class of compounds with the general formula R 1 4NOH, wherein R is four identical or different aliphatic or aromatic groups. 1 It can be selected from one or more of methyl, ethyl, propyl, butyl, etc. Examples of quaternary ammonium bases suitable for the present invention include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc. The first catalyst can also be a combination of an alkali metal hydroxide and a tetraalkylammonium halide. The general formula of the tetraalkylammonium halide is R 2 4NX, where R 2 are four identical or different aliphatic or aromatic hydrocarbon groups, such as methyl, ethyl, propyl, butyl, etc., and X is a halogen atom, such as fluorine, chlorine, bromine, iodine. Examples of the combination of an alkali metal hydroxide and a tetraalkylammonium halide include sodium hydroxide and tetrabutylammonium bromide, etc.

[0073] The molar ratio of the first catalyst to the compound of formula B can be 0.1:1 to 2:1, preferably 0.9:1 to 1.1:1, for example 1.05:1, 1.1:1, 1.5:1. In some embodiments, in step (1), the compound of formula B and the first catalyst are first salified, and then the compound of formula C is added dropwise for condensation reaction.

[0074] In step (1), the condensate obtained by the condensation reaction of the compound of formula B and the compound of formula C under the action of the first catalyst may be one or both of the compound of formula D and the compound of formula D', and may also contain an azobenzene compound.

[0075] In step (1), the molar ratio of the compound of formula B to the compound of formula C can be 2:1 to 15:1, preferably 4:1 to 10:1, more preferably 5:1 to 8:1, such as 6:1 or 7:1.

[0076] In step (1), the condensation reaction can be carried out at 40 to 90° C., preferably 65 to 85° C., for example, the reaction temperature can be 60° C., 70° C., 75° C., 80° C. The condensation reaction needs to be carried out under vacuum conditions, with a pressure range of -0.09 to -0.1 MPa.

[0077] The second catalyst used in step (1) can be a porous metal catalyst or a supported metal catalyst. Porous metal catalysts are also called sponge metal catalysts. Porous metal catalysts suitable for the present invention include Raney nickel (also known as skeleton nickel), Raney cobalt, Raney copper, etc. Supported metal catalysts include metals as catalytic active centers and carriers for supporting metals. The metals suitable for the supported metal catalysts of the present invention can be nickel, cobalt, copper, platinum, palladium, ruthenium, rhodium, etc., and the carrier can be carbon, alumina, silica gel, molecular sieves, etc., and the carbon as a carrier can be activated carbon. The ratio of the amount of metal in the second catalyst to the amount of the condensate can be 0.0001:1 to 0.2:1.

[0078] In step (1), the condensate generated by the condensation reaction is subjected to a hydrogenation reduction reaction under the action of a second catalyst to generate a compound of formula E. In step (1), the reduction reaction can be carried out at 40 to 120° C., preferably 60 to 90° C., for example, the reaction temperature can be 70° C., 75° C., or 80° C. The hydrogen pressure in the reduction reaction can be 0.5 to 5 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, or 2.5 MPa.

[0079] In step (1), the compound of formula B itself can be used as a solvent, or solvents such as toluene and xylene can be used. After the reaction in step (1) is completed, the reaction solution is filtered, washed with water, and separated into phases, and the organic phase is subjected to reduced pressure distillation to remove light components to obtain the compound of formula E.

[0080] The third catalyst used in step (2) may be the aforementioned supported metal catalyst, such as Pt / C. The molar ratio of the metal in the third catalyst to the compound of formula III may be 0.0001:1 to 0.2:1.

[0081] In step (2), after the reaction, the carbonyl carbon atom in the compound of formula F is connected to the amino nitrogen atom in the compound of formula E. Therefore, a suitable compound of formula F can be selected for reaction according to the R3 group contained in the compound of formula A to be prepared. The molar ratio of the compound of formula F to the compound of formula E can be 1:1 to 15:1, for example, 2:1, 3:1, 5:1, 8:1, 10:1. The reaction temperature of step (2) can be 40 to 150°C, for example, 50°C, 80°C, 100°C, 120°C. The hydrogen pressure in step (2) can be 0.5 to 5MPa, for example, 1MPa, 1.5MPa, 2MPa, 2.5MPa.

[0082] In step (2), the compound of formula F, which is a reaction raw material, can be used as a solvent. After the reaction in step (2) is completed, the reaction solution is filtered and the light components are removed by reduced pressure distillation to obtain the compound of formula A.

[0083] In the present invention, liquid chromatography (LC) or gas chromatography (GC) can be used to determine whether each step of the reaction has reached the endpoint, thereby determining the appropriate reaction time.

[0084] The raw materials of the rubber composition generally include a diene elastomer, a reinforcing filler, an antioxidant and a crosslinking agent. Herein, the rubber composition includes unvulcanized rubber and vulcanized rubber. The unvulcanized rubber can be vulcanized (cured) to obtain vulcanized rubber.

[0085] The raw materials of the rubber composition of the present invention include a diene elastomer and one or more compounds of formula A as antioxidants, wherein the total amount of the compounds of formula A can be 1-3 parts by mass, such as 1.3 parts by mass, 1.5 parts by mass, 1.8 parts by mass, 2 parts by mass, 2.2 parts by mass, and 2.5 parts by mass, based on 100 parts by mass of the diene elastomer. Herein, unless otherwise specified, 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 in the raw materials of the rubber composition.

[0086] Herein, diene elastomer refers to an elastomer whose monomers include dienes (such as butadiene, isoprene). Suitable diene elastomers for the present invention can be various diene elastomers known in the art, including but not limited to one or more selected from natural rubber (NR), cis-1,4-butadiene rubber (BR), isoprene rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), isoprene / butadiene copolymer, isoprene / styrene copolymer and isoprene / butadiene / styrene copolymer. In some preferred embodiments, diene elastomer includes natural rubber and cis-1,4-butadiene rubber, or is composed of natural rubber and cis-1,4-butadiene rubber. The mass ratio of natural rubber and cis-1,4-butadiene rubber is preferably 1:2 to 2:1, such as 1:1.5 to 1.5:1, 4.5:5.5 to 5.5:4.5, 1:1.

[0087] The raw materials of the rubber composition of the present invention include one or more compounds of formula A, such as two or more compounds of formula A. In some embodiments, the rubber composition of the present invention does not contain other antioxidants except the compounds of formula A. In some embodiments, the raw materials of the rubber composition of the present invention include one or more compounds selected from compounds of formula I, compounds of formula II, compounds of formula IV, compounds of formula VI, compounds of formula VIII, compounds of formula X, compounds of formula XII and compounds of formula XIV, such as two or more compounds. In the raw materials of the rubber composition of the present invention, the amount of the compound of formula A can be 1-3 parts by mass, for example, it can be 1.3 parts by mass, 1.5 parts by mass, 1.8 parts by mass, 2 parts by mass, 2.2 parts by mass, 2.5 parts by mass or in the range of any two of the above values. Controlling the amount of the compound of formula A within the aforementioned range is conducive to ensuring the effect of improving fatigue aging resistance at a lower dosage.

[0088] In a preferred embodiment, in the raw materials of the rubber composition of the present invention, the number of compounds of formula A is two or more. The combination of two or more compounds of formula A in the rubber composition can achieve a synergistic effect of significantly improving fatigue aging resistance. In some embodiments, in the raw materials of the rubber composition of the present invention, the number of compounds of formula A is two. In some embodiments, the raw materials of the rubber composition of the present invention include two compounds selected from the group consisting of compounds of formula I, compounds of formula II, compounds of formula IV, compounds of formula VI, compounds of formula VIII, compounds of formula X, compounds of formula XII, and compounds of formula XIV. In some embodiments, the raw materials of the rubber composition of the present invention include compounds of formula I and compounds of formula II. In some embodiments, the raw materials of the rubber composition of the present invention include compounds of formula IV and compounds of formula VI. In some embodiments, the raw materials of the rubber composition of the present invention include compounds of formula VIII and compounds of formula X. In some embodiments, the raw materials of the rubber composition of the present invention include compounds of formula XII and compounds of formula XIV. In the present invention, the mass ratio of the two compounds of formula A is preferably 1:2 to 2:1, for example, it can be 1:1.5, 1:1.2, 1:1, 1.2:1, 1.5:1 or the range of any two of the above values. Controlling the mass ratio of the two compounds of formula A within the above range is conducive to obtaining a synergistic effect of improving fatigue aging resistance. In a preferred embodiment, the raw materials of the rubber composition of the present invention include a compound of formula I and a compound of formula II, the total mass of the compound of formula I and the compound of formula II can be 1-3 parts by mass, for example, 1.5-2 parts by mass, and the mass ratio of the compound of formula I and the compound of formula II can be 1:2 to 2:1, for example, 1:1.5 to 1.5:1.

[0089] The raw material of the rubber composition of the present invention may include reinforcing filler. In the raw material of the rubber composition of the present invention, the amount of reinforcing filler can be 30-70 mass parts, such as 40 mass parts, 45 mass parts, 50 mass parts, 55 mass parts, 60 mass parts. Reinforcing filler suitable for the present invention can be a conventional reinforcing filler for rubber composition, including but not limited to one or more selected from carbon black, white carbon black, titanium oxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, clay and talcum. In some preferred embodiments, reinforcing filler comprises carbon black, or reinforcing filler is carbon black.

[0090] The raw materials of the rubber composition of the present invention include a crosslinking agent, such as sulfur. In the raw materials of the rubber composition of the present invention, the amount of sulfur can be 0.5-3 parts by mass, such as 1 part by mass, 1.5 parts by mass, 2 parts by mass, 2.5 parts by mass. The sulfuric acid can be sublimated sulfur.

[0091] The raw materials of the rubber composition of the present invention may further include other ingredients commonly used in rubber compositions, including but not limited to one or more selected from the group consisting of softeners, protective waxes, activators and accelerators.

[0092] Softener can be used to improve the processing properties of rubber composition. Softener can include petroleum softener, such as naphthenic oil, aromatic oil, process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, vaseline, etc., and can also include fatty oil softener, such as stearic acid, castor oil, linseed oil, rapeseed oil, coconut oil, wax (such as beeswax, carnauba wax and lanolin), tall oil, linoleic acid, palmitic acid, lauric acid, etc. In the raw material of rubber composition of the present invention, the amount of softener can be 2-15 mass parts, such as 3 mass parts, 5 mass parts, 7 mass parts, 8 mass parts, 9 mass parts, 10 mass parts, 11 mass parts, 13 mass parts. In some preferred embodiments, softener includes aromatic oil and stearic acid, or is composed of aromatic oil and stearic acid. The mass ratio of aromatic oil and stearic acid can be 1:1 to 5:1, such as 2:1, 3:1, 3.5:1, 4:1. In some preferred embodiments, in the raw materials of the rubber composition of the present invention, the amount of aromatic oil used is 1-10 parts by mass, for example, 5 parts by mass, 6 parts by mass, 7 parts by mass, 8 parts by mass, and 9 parts by mass; the amount of stearic acid used is 1-5 parts by mass, for example, 1.5 parts by mass, 2 parts by mass, and 3 parts by mass.

[0093] The protective wax can migrate from the inside of the rubber to the surface to form a wax film, which plays a role in isolating the rubber surface from the external environment. The protective wax is optionally added. When the raw materials of the rubber composition of the present invention include the protective wax, the amount of the protective wax can be 1-5 parts by mass, such as 1.5 parts by mass, 2 parts by mass, 3 parts by mass, and 4 parts by mass.

[0094] The activating agent can accelerate the vulcanization speed, improve the thermal conductivity, wear resistance, tear resistance and the like of rubber. In the raw material of the rubber composition of the present invention, the amount of the activating agent can be 1-10 mass parts, such as 2 mass parts, 3 mass parts, 4 mass parts, 5 mass parts, 6 mass parts, 7 mass parts, 8 mass parts, 9 mass parts. In some preferred embodiments, the activating agent includes ZnO, or the activating agent is ZnO. In some preferred embodiments, in the raw material of the rubber composition of the present invention, the amount of ZnO is 3-8 mass parts, such as 4 mass parts, 5 mass parts, 6 mass parts, 7 mass parts.

[0095] The accelerator is usually a vulcanization accelerator, which can be selected from sulfonamide vulcanization accelerators, thiazole vulcanization accelerators, thiuram vulcanization accelerators, thiourea vulcanization accelerators, guanidine vulcanization accelerators, dithiocarbamate vulcanization accelerators, aldehyde amine vulcanization accelerators, aldehyde ammonia vulcanization accelerators, imidazoline vulcanization accelerators and xanthogenic acid vulcanization accelerators. In the raw materials of the rubber composition of the present invention, the amount of the accelerator can be 0.2-2 mass parts, such as 0.5 mass parts, 0.6 mass parts, 0.8 mass parts, 1 mass parts, 1.5 mass parts. In some preferred embodiments, the accelerator is accelerator NS (N- tert-butyl -2-benzothiazole sulfonamide).

[0096] In addition, when necessary, the rubber composition may also contain plasticizers such as DMP (dimethyl phthalate), DEP (diethyl phthalate), DBP (dibutyl phthalate), DHP (diheptyl phthalate), DOP (dioctyl phthalate), DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), BBP (butyl benzyl phthalate), DWP (dilauryl phthalate), and DCHP (dicyclohexyl phthalate), etc. The amount of the plasticizer may be a conventional amount in the art.

[0097] In some preferred embodiments, the raw materials of the rubber composition of the present invention include: 100 parts by mass of a diene elastomer, 0.5-3 parts by mass of sulfur, 1-3 parts by mass of a compound of formula A, 30-70 parts by mass of carbon black, 1-10 parts by mass of ZnO, 1-5 parts by mass of stearic acid, 1-10 parts by mass of aromatic oil and 0.2-2 parts by mass of an accelerator, or are composed of the above components; wherein the diene elastomer preferably includes natural rubber and butadiene rubber in a mass ratio of 1:2-2:1, and the accelerator is preferably accelerator NS.

[0098] The unvulcanized rubber of the present invention can be prepared by conventional rubber mixing methods, for example, by a two-stage mixing method: a first stage of thermomechanical (e.g., internal mixer) mixing, mixing the rubber composition raw materials except the crosslinking agent and the accelerator, kneading the entire mixture until the maximum temperature between 110°C and 190°C is reached to obtain a first stage of rubber; a second stage of thermomechanical (e.g., open mixer) mixing, after the first stage of rubber is cooled, mixing the first stage of rubber with the crosslinking agent and the accelerator until the maximum temperature is below 110°C to obtain a second stage of rubber, i.e., the unvulcanized rubber.

[0099] Vulcanized rubber can be obtained by vulcanizing (curing) the unvulcanized rubber. The vulcanization temperature is usually 130-200°C, such as 140-160°C, 145±5°C; the vulcanization time depends on the vulcanization temperature, vulcanization system and vulcanization kinetics, and is usually 15-60 minutes, such as 20-40 minutes, 30±5 minutes.

[0100] The rubber composition of the present invention is used in rubber products, especially tires. Compared with the use of antioxidant 6PPD alone, the use of formula A compounds, especially two or more formula A compounds (such as formula I compounds and formula II compounds) can significantly improve the fatigue aging resistance of rubber products. Therefore, the present invention also provides a rubber product, the rubber product contains the rubber composition described herein. The rubber product can be a tire, a rubber shoe, a sealing strip, a sound insulation board, a shock pad, etc. The rubber product is preferably a tire, such as a sidewall rubber, a tread rubber, etc.

[0101] The present invention also provides the use of the compound of formula A in improving the fatigue aging resistance of the rubber composition, and a method for improving the fatigue aging resistance of the rubber composition. Preferably, the use or method of the present invention comprises: based on the mass of the diene elastomer contained in the rubber composition being 100 parts by mass, adding 1-3 parts by mass of the compound of formula A to the raw materials of the rubber composition. In the use or method of the present invention, the amount and proportion of the compound of formula A, the preferred compound of formula A and the raw material composition of the rubber composition are preferably as described in any embodiment of the present invention.

[0102] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0103] The raw materials used in the examples are: natural rubber (SCR5), Xishuangbanna Sinochem Rubber Co., Ltd.; butadiene rubber (BR9000), Shandong Yuhuang Chemical Co., Ltd.; antioxidant 6PPD, Shengao Chemical Technology Co., Ltd.; carbon black N550, zinc oxide, aromatic oil, stearic acid, sublimated sulfur and accelerator NS are all common raw materials in the rubber industry.

[0104] Preparation Example 1: Synthesis of Compounds of Formula I

[0105] (1) Synthesis of compound of formula III

[0106] In a 500mL four-necked flask, 132.4g (1.23mol) of m-toluidine and 87.6g (0.24mol) of a 25% aqueous solution of tetramethylammonium hydroxide (TMAOH) were added, stirred and heated to 40-50°C, and dehydrated by vacuum distillation to form salts of TMAOH and m-toluidine. During this process, the reaction solution gradually changed from yellow to dark red; the temperature was gradually raised to 72°C. When the fraction was about 50% of the amount of 25% tetramethylammonium hydroxide added as catalyst, 30g (0.22mol) of m-nitrotoluene was added dropwise at 72°C under reduced pressure (-0.098MPa). The addition time was about 3h. After the addition was completed, the temperature was kept for 1h. LC was monitored until the reaction of m-nitrotoluene was complete to obtain a condensation liquid.

[0107] The condensation liquid was transferred to a 500 mL stainless steel reactor, 50 g of deionized water and 40 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature was raised to 75°C, the pressure was raised to 1.5 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. The reaction liquid was filtered, washed with water, and phase-separated. The organic phase was distilled under reduced pressure (-0.1 MPa, 160°C) to remove light components to obtain 37.1 g of compound III (yield of about 80%), and the content detected by GC was >99.5%.

[0108]

[0109] LC-MS (m / z): 212.22 (MH + ).

[0110] 1 H NMR (400MHz, DMSO-d6) δ6.95–6.88(m,2H),6.79(d,J=8.3Hz,1H),6.48(d,J=2.6Hz,1H),6.43–6.30(m,4H),4.80(s,2H),2.14(s,3H),2.02(s,3H).

[0111] (2) Synthesis of Compounds of Formula I

[0112] 37.1g of compound III, 60g (0.60mol) of 4-methyl-2-pentanone and 0.5g of Pt / C catalyst were put into a reactor, replaced with hydrogen 3 times, heated to 100°C, and pressurized to 1.5MPa for reaction. GC was used for detection. When the content of compound III was less than 0.1%, the reaction was stopped. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by distillation at -0.1MPa and 180°C to obtain 49.2g of compound I (yield of about 95%). The content detected by GC was >98.5%. Properties: reddish brown solid.

[0113]

[0114] LC-MS (m / z): 296.44 (MH + ).

[0115] Preparation Example 2: Synthesis of Compound of Formula II

[0116] (1) Synthesis of compound of formula III

[0117] The synthesis of the compound of formula III is the same as that of Preparation Example 1.

[0118] (2) Synthesis of Compound II

[0119] 30g (0.14mol) of compound III, 100g (1.38mol) of 2-butanone and 0.6g of Pt / C catalyst were put into a reactor, replaced with hydrogen 3 times, heated to 80°C, and pressurized to 1.5MPa for reaction. Detected by GC, when the content of compound III was <0.1%, the reaction was stopped. Cooled, filtered to remove the catalyst, and distilled at -0.1MPa and 150°C to remove the light components to obtain 36.7g of compound II (yield of about 98%), and the content detected by GC was >98.5%. Properties: reddish brown solid.

[0120]

[0121] LC-MS (m / z): 268.40 (MH + ).

[0122] 1 H NMR (400MHz, DMSO-d6) δ6.96–6.87(m,2H),6.83(d,J=8.4Hz,1H),6.45(d,J=2.6Hz,1H),6.42–6.29(m,4H),4.98(d,J=8.6Hz,1H),2.14(s ,3H),2.04(s,3H),1.81–1.66(m,J=6.7Hz,1H),1.45(dt,J=13.9,7.1Hz,1H),1.21(dt,J=13.5,6.8Hz,1H),0.89(dd,J=16.2,6.6Hz,6H).

[0123] Preparation Example 3: Synthesis of Compound IV

[0124] (1) Synthesis of Compound V

[0125] In a 500mL four-necked flask, 160.5g (1.5mol) of 2-methylaniline and 91g (0.25mol) of a 25% aqueous solution of tetramethylammonium hydroxide (TMAOH) were added, and the mixture was stirred and heated to 40-50°C, and dehydrated by vacuum distillation to form salts of TMAOH and 2-methylaniline. During this process, the reaction solution gradually changed from yellow to dark red. The mixture was gradually heated to 72°C. When the fraction was about 50% of the amount of the catalyst 25% tetramethylammonium hydroxide solution charged, 34.3g (0.25mol) of 3-methylnitrobenzene was added dropwise at 72°C under reduced pressure (-0.098MPa). The addition time was about 3h. After the addition was completed, the mixture was kept warm for 1h. LC was monitored until the reaction of 3-methylnitrobenzene was complete to obtain a condensation solution.

[0126] The condensation liquid was transferred to a 500 mL stainless steel reactor, 50 g of deionized water and 40 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature was raised to 75 ° C, the pressure was raised to 1.5 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. Then, the mixture was filtered, washed with water, and separated into phases. The organic phase was subjected to reduced pressure distillation (-0.1 MPa, 170 ° C) to remove light components to obtain 42.8 g of the compound of formula V (yield of about 80%), the content of which was >98% when detected by GC, and it was a light yellow solid at room temperature.

[0127]

[0128] LC-MS (m / z): 212.28 (MH + ).

[0129] 1 H NMR (400MHz, CDCl3) δ7.09 (d, J = 7.3Hz, 1H), 6.99 (t, J = 7.7Hz, 1H), 6.91 (d, J = 8.2Hz, 1H) ,6.69(t,J=7.3Hz,1H),6.55(s,1H),6.49(dd,J=14.3,5.2Hz,2H),4.91(s,1H),3.48(br s,2H),2.23(s,3H),2.11(s,3H).

[0130] (2) Synthesis of Compound IV

[0131] 42.5g (0.2mol) of the compound of formula V, 129g (1.5mol) of 2-pentanone and 0.5g of Pt / C catalyst were put into a reactor, replaced with hydrogen for 3 times, heated to 90°C, and pressurized to 1.5MPa for reaction. The reaction was detected by GC. When the content of the compound of formula V was less than 0.1%, the reaction was stopped. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by distillation at -0.1MPa and 180°C to obtain 53.6g of the compound of formula IV (yield of about 95%), and the content detected by GC was >98.7%. Properties: reddish brown solid.

[0132]

[0133] LC-MS (m / z): 282.40 (MH + ).

[0134] Preparation Example 4: Synthesis of Compound VI

[0135] (1) Synthesis of Compound VII

[0136] In a 500mL four-necked flask, 160.5g (1.5mol) of 4-methylaniline and 100.1g (0.275mol) of a 25% aqueous solution of tetramethylammonium hydroxide (TMAOH) were added, and the mixture was stirred and heated to 40-50°C, and dehydrated by vacuum distillation to form salts of TMAOH and 4-methylaniline. During this process, the reaction solution gradually changed from yellow to dark red; the mixture was gradually heated to 72°C, and when the fraction was about 50% of the amount of the catalyst 25% tetramethylammonium hydroxide solution charged, 34.3g (0.25mol) of 3-methylnitrobenzene was added dropwise at 72°C under reduced pressure (-0.098MPa), and the addition time was about 3h. After the addition was completed, the mixture was kept warm for 1h, and LC was monitored until the reaction of 3-methylnitrobenzene was complete to obtain a condensation solution.

[0137] The condensation liquid was transferred to a 500 mL stainless steel reactor, 50 g of deionized water and 40 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature was raised to 75 ° C, the pressure was raised to 1.5 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. Then, the mixture was filtered, washed with water, and separated into phases. The organic phase was subjected to reduced pressure distillation (-0.1 MPa, 170 ° C) to remove light components to obtain 46.1 g of the compound of formula VII (yield of about 86%), the content of which was >98% detected by GC, and it was a light yellow solid at room temperature.

[0138]

[0139] 1H NMR(400MHz, CDCl3)δ7.01(t,J=6.6Hz,3H),6.67–6.63(m,2H),6.62(d,J=2.5Hz,1H ),6.55(dd,J=8.3,2.6Hz,1H),5.02(s,1H),3.38(s,2H),2.29(s,3H),2.19(s,3H).

[0140] 13 C NMR (101MHz, CDCl3) δ144.36,142.87,133.94,132.41,129.72,127.73,125.32,117.69,114.90,113.67,20.47,17.99.

[0141] (2) Synthesis of Compound VI

[0142] 42.5g (0.2mol) of compound VII, 162.4g (2.8mol) of acetone and 0.5g of Pt / C catalyst were put into a reactor, replaced with hydrogen for 3 times, heated to 70°C, and pressurized to 1.5MPa for reaction. GC was used for detection. When the content of compound VII was less than 0.1%, the reaction was stopped. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by distillation at -0.1MPa and 180°C to obtain 48.8g of compound VI (yield of about 96%). The content detected by GC was >98.9%. Properties: reddish brown solid.

[0143]

[0144] LC-MS (m / z): 254.30 (MH + ).

[0145] Preparation Example 5: Synthesis of Compound VIII

[0146] (1) Synthesis of Compound IX

[0147] In a 500mL four-necked flask, 149g (1.23mol) of m-ethylaniline and 87.4g (0.24mol) of a 25% aqueous solution of tetramethylammonium hydroxide (TMAOH) were added, stirred and heated to 40-50°C, and dehydrated by vacuum distillation to form salts of TMAOH and p-toluidine. During this process, the reaction solution gradually changed from yellow to dark red; the temperature was gradually raised to 72°C. When the fraction was about 50% of the amount of 25% tetramethylammonium hydroxide added as catalyst, 30.2g (0.22mol) of m-nitrotoluene was added dropwise at 72°C under reduced pressure (-0.098MPa). The addition time was about 3h. After the addition was completed, the temperature was kept for 1h. LC was monitored until the reaction of m-nitrotoluene was complete to obtain a condensation liquid.

[0148] The condensation liquid was transferred to a 500 mL stainless steel reactor, 50 g of deionized water and 40 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature was raised to 75° C., the pressure was raised to 1.5 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. The reaction liquid was filtered, washed with water, and phase-separated. The organic phase was distilled under reduced pressure (-0.1 MPa, 160° C.) to remove light components to obtain 40.3 g of the compound of formula IX (yield of about 81%), and the content detected by GC was >97.2%.

[0149]

[0150] LC-MS (m / z): 226.20 (MH + ).

[0151] (2) Synthesis of compound of formula VIII

[0152] 38.5g (0.17mol) of the compound of formula IX, 100g (1.0mol) of 4-methyl-2-pentanone and 0.5g of Pt / C catalyst were put into a reactor, replaced with hydrogen 3 times, heated to 100°C, and pressurized to 1.5MPa for reaction. Detected by GC, when the content of the compound of formula IX was <0.1%, the reaction was stopped. Cooled, filtered to remove the catalyst, and distilled at -0.1MPa and 180°C to remove the light components to obtain 51g of the compound of formula VIII (yield of about 96.5%), and the content detected by GC was >99.1%. Properties: red liquid.

[0153]

[0154] LC-MS (m / z): 310.46 (MH + ).

[0155] Preparation Example 6: Synthesis of Compound X

[0156] (1) Synthesis of Compound XI

[0157] In a 500mL four-necked flask, 131.8g (1.23mol) of p-toluidine and 87.4g (0.24mol) of a 25% aqueous solution of tetramethylammonium hydroxide (TMAOH) were added, stirred and heated to 40-50°C, and dehydrated by vacuum distillation to form salts of TMAOH and p-toluidine. During this process, the reaction solution gradually changed from yellow to dark red; the temperature was gradually raised to 72°C. When the fraction was about 50% of the amount of 25% tetramethylammonium hydroxide added as catalyst, 33.2g (0.22mol) of m-nitroethylbenzene was added dropwise at 72°C under reduced pressure (-0.098MPa). The addition time was about 3h. After the addition was completed, the temperature was kept for 1h. LC was monitored until the reaction of m-nitrotoluene was complete to obtain a condensation solution.

[0158] The condensation liquid was transferred to a 500 mL stainless steel reactor, 50 g of deionized water and 40 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature was raised to 75° C., the pressure was raised to 1.5 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. The reaction liquid was filtered, washed with water, and phase-separated. The organic phase was distilled under reduced pressure (-0.1 MPa, 160° C.) to remove light components to obtain 42 g of the compound of formula XI (yield of about 84.5%), and the content detected by GC was >97%.

[0159]

[0160] LC-MS (m / z): 226.20 (MH + ).

[0161] (2) Synthesis of Compound X

[0162] 40.7g (0.18) of the compound of formula XI, 108g (1.50mol) of 2-butanone and 0.5g of Pt / C catalyst were put into a reaction kettle, replaced with hydrogen for 3 times, heated to 80°C, and pressurized to 1.5MPa for reaction. The reaction was detected by GC. When the content of the compound of formula XI was <0.1%, the reaction was stopped. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by distillation at -0.1MPa and 180°C to obtain 49.8g of the compound of formula X (yield of about 98%), and the content detected by GC was >98.2%. Properties: red solid.

[0163]

[0164] LC-MS (m / z): 282.21 (MH + ).

[0165] Preparation Example 7: Synthesis of Compound of Formula XII

[0166] (1) Synthesis of Compound XIII

[0167] In a 1000mL four-necked flask, 347.9g (3.25mol) of o-toluidine and 200g (0.55mol) of a 25% aqueous solution of tetramethylammonium hydroxide (TMAOH) were added, stirred and heated to 60°C, and dehydrated by vacuum distillation to form salts of TMAOH and o-toluidine. During this process, the reaction solution gradually changed from yellow to reddish brown; the temperature was gradually raised to 80°C. When the fraction was about half of the amount of 25% tetramethylammonium hydroxide catalyst, 68.5g (0.50mol) of o-nitrobenzene was added dropwise at 80°C under reduced pressure (-0.097MPa). The addition time was about 3h. After the addition was completed, the temperature was kept for 1h. The reaction of o-nitrobenzene was monitored by LC until the reaction was complete to obtain a condensation solution.

[0168] The condensation liquid was transferred to a 500 mL stainless steel reactor, 65 g of deionized water and 38 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature and pressure were raised to 78°C and 2.0 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. The reaction liquid was filtered, washed with water, and phase separated; the organic phase was distilled under reduced pressure (-0.1 MPa, 180°C) to remove light components to obtain 31.8 g of compound XIII (yield of about 30%), and the content detected by GC was >92.5%.

[0169]

[0170] LC-MS (m / z): 212.20 (M-H+)

[0171] (2) Synthesis of Compound XII

[0172] 30g (0.14mol) of compound XIII, 120.6g (1.4mol) of 2-pentanone and 0.8g of Pt / C were put into a reactor, heated to 90°C, and the pressure was raised to 1.5MPa after hydrogen substitution for reaction. When the content of compound XIII was <0.1% by GC detection, the temperature was lowered to stop the reaction. Filter and remove the light components by vacuum distillation (-0.1MPa, 160°C) to obtain 38g of compound XII (yield of about 96%), and the content detected by GC was >96.2%. Properties: black solid.

[0173]

[0174] LC-MS (m / z): 282.43 (MH + ).

[0175] Preparation Example 8: Synthesis of Compound of Formula XIV

[0176] (1) Synthesis of Compound XV

[0177] In a 1000mL four-necked flask, add 347.9g (3.25mol) of p-toluidine and 200g (0.55mol) of 25% tetramethylammonium hydroxide (TMAOH) aqueous solution, stir and heat to 60°C, dehydrate by vacuum distillation to make TMAOH and o-toluidine form salts, during which the reaction liquid gradually changes from yellow to reddish brown; gradually heat to 80°C, when the fraction is about half of the amount of 25% tetramethylammonium hydroxide catalyst, distill at 80°C under reduced pressure (-0.097MPa) and dropwise add 68.5g (0.50mol) of o-nitrobenzene, the addition time is about 3h, and after the addition is completed, keep warm for 1h, monitor by LC until the reaction of o-nitrobenzene is complete, and obtain a condensation liquid.

[0178] The condensation liquid was transferred to a 500 mL stainless steel reactor, 65 g of deionized water and 38 g of catalyst skeleton nickel were added, hydrogen was replaced three times, the temperature and pressure were raised to 78°C and 2.0 MPa for reaction, and LC was monitored until the nitro and nitroso compounds were completely reduced. The reaction liquid was filtered, washed with water, and phase separated; the organic phase was distilled under reduced pressure (-0.1 MPa, 180°C) to remove light components to obtain 34 g of compound XV (yield of about 32%), and the content detected by GC was >93.4%.

[0179]

[0180] LC-MS (m / z): 212.30 (MH + ).

[0181] (2) Synthesis of Compound XIV

[0182] 30g (0.14mol) of compound XV, 104.5g (1.8mol) of acetone and 0.8g of Pt / C were put into a reactor, heated to 70°C, and the pressure was raised to 1.5MPa after hydrogen substitution for reaction. When the content of compound XV detected by GC was <0.1%, the temperature was lowered to stop the reaction. Filter and remove the light components by vacuum distillation (-0.1MPa, 160°C) to obtain 34.7g of compound XIV (yield of about 97.5%), and the content detected by GC was >95.8%. Properties: dark red solid.

[0183]

[0184] LC-MS (m / z): 240.35 (MH + ).

[0185] Examples 1-17 and Comparative Example 1

[0186] According to the formulations shown in Table 1, Table 2 and Table 3, the rubber compositions of Examples 1-17 and Comparative Example 1 were prepared using the following process:

[0187] (1) adding natural rubber and butadiene rubber into an internal mixer, and then adding carbon black, zinc oxide, stearic acid, aromatic oil and antioxidant (antioxidant 6PPD, one or two of the compounds of formula I, formula II, formula IV, formula VI, formula VIII, formula X, formula XII and formula XIV), kneading until the temperature of the rubber material rises to 130° C. and the rubber is discharged to obtain a rubber section;

[0188] (2) After the first stage of the rubber is cooled, the first stage of the rubber is mixed on an open mixing mill, and accelerator NS and sulfur are added, and the mixture is kneaded until the temperature of the rubber reaches 70°C and a sheet is produced to obtain the second stage of the rubber;

[0189] (3) The second-stage rubber is vulcanized (145°C x 30 min) to obtain a vulcanized rubber.

[0190] Table 1: Rubber composition formula of Comparative Example 1 and Examples 1-5 (unit: mass parts)

[0191]

[0192]

[0193] Table 2: Rubber composition formulations of Examples 6-11 (unit: mass parts)

[0194]

[0195] Table 3: Rubber composition formulations of Examples 12-17 (unit: parts by mass)

[0196]

[0197] Test Example 1: Flexure-cracking resistance test

[0198] According to the standard GB / T 13934-2006 Determination of flex cracking and crack growth of vulcanized rubber or thermoplastic rubber (Demesia type), the vulcanized rubber was subjected to a flex cracking performance test, and the flexing times corresponding to the early appearance of cracks (grade 1, grade 2) and specimen damage (grade 6) were recorded respectively. The results are shown in Tables 4, 5 and 6.

[0199] Table 4: Flex-crack resistance test results of the rubber compositions of Comparative Example 1 and Examples 1-5

[0200]

[0201]

[0202] Table 5: Flex-crack resistance test results of the rubber compositions of Examples 6-11

[0203]

[0204] Table 6: Flex-crack resistance test results of the rubber compositions of Examples 12-17

[0205]

[0206]

[0207] Note: The percentage values ​​in Table 4, Table 5 and Table 6 refer to the growth rate of the flexion times of the corresponding embodiments relative to the flexion times of Comparative Example 1.

[0208] As shown in Tables 4-6, the rubber compositions of Examples 1-17 (containing the compound of formula A) have obvious advantages over the rubber composition of comparative example 1 (containing the antioxidant 6PPD) in both the early stage crack resistance and the later stage crack growth rate slowdown, and the performance improvement is more than 30% on average. In addition, the flex crack resistance of Example 6 is significantly better than that of Example 1 and Example 3; the flex crack resistance of Examples 5, 7, and 8 is significantly better than that of Example 2 and Example 4; the flex crack resistance of Example 9 is significantly better than that of Example 12 and Example 13; the flex crack resistance of Example 10 is significantly better than that of Example 14 and Example 15; the flex crack resistance of Example 11 is significantly better than that of Example 16 and Example 17. This shows that the combination of two compounds of formula A (for example, the combination of the compound of formula I and the compound of formula II, the combination of the compound of formula IV and the compound of formula VI, the combination of the compound of formula VIII and the compound of formula X, and the combination of the compound of formula XII and the compound of formula XIV) shows a significant synergistic effect in improving the flex crack resistance. Among them, when the compound of formula I and the compound of formula II are used together, the effect of improving the flex crack resistance is the most excellent.

[0209] Test Example 2: Dynamic tensile fatigue resistance test

[0210] According to the standard GBT1688-2008 for the determination of tensile fatigue of vulcanized rubber, the dynamic tensile fatigue resistance test of the vulcanized rubber was carried out, and the number of cycles of the sample under the test conditions of 50% tensile deformation and 5 Hz frequency until the sample broke was recorded. The results are shown in Tables 7 and 8.

[0211] Table 7: Dynamic tensile fatigue resistance test results of the rubber compositions of Comparative Example 1 and Examples 1-8

[0212]

[0213]

[0214] Table 8: Dynamic tensile fatigue resistance test results of the rubber compositions of Examples 9-17

[0215]

[0216] Note: The percentage values ​​in Table 7 and Table 8 refer to the growth rate of the number of stretching times at fatigue fracture of the corresponding embodiments relative to the number of stretching times at fatigue fracture of Comparative Example 1.

[0217] As can be seen from Tables 7 and 8, the dynamic tensile fatigue resistance of the rubber compositions of Examples 1-17 (containing the compound of formula A) has obvious advantages over the rubber composition of Comparative Example 1 (containing the antioxidant 6PPD), and the performance improvement is more than 30% on average. In addition, the dynamic tensile fatigue resistance of Example 6 is better than that of Example 1 and Example 3; the dynamic tensile fatigue resistance of Examples 5, 7, and 8 is better than that of Example 2 and Example 4; the dynamic tensile fatigue resistance of Example 9 is better than that of Example 12 and Example 13; the dynamic tensile fatigue resistance of Example 10 is better than that of Example 14 and Example 15; the dynamic tensile fatigue resistance of Example 11 is better than that of Example 16 and Example 17. This shows that the combination of two compounds of formula A (for example, the combination of a compound of formula I and a compound of formula II, the combination of a compound of formula IV and a compound of formula VI, the combination of a compound of formula VIII and a compound of formula X, and the combination of a compound of formula XII and a compound of formula XIV) shows a synergistic effect in improving the dynamic tensile fatigue resistance. Among them, when the compound of formula I and the compound of formula II are used in combination, the effect of improving the dynamic tensile fatigue resistance is the most excellent.

Claims

1. A rubber composition, characterized in that: The raw materials of the rubber composition include 100 parts by mass of a diene elastomer and 1 to 3 parts by mass of two or more compounds of formula A: In formula A, R1, R2 and R3 are each independently selected from C1-C8 alkyl groups.

2. The rubber composition according to claim 1, characterized in that In formula A, R1 and R2 are each independently selected from C1-C3 alkyl, preferably each independently selected from methyl and ethyl; and / or In formula A, R3 is selected from C3-C8 alkyl, preferably from C3-C6 alkyl, for example from C4-C6 alkyl.

3. The rubber composition according to claim 1, characterized in that The raw materials of the rubber composition include two compounds selected from the group consisting of a compound of formula I, a compound of formula II, a compound of formula IV, a compound of formula VI, a compound of formula VIII, a compound of formula X, a compound of formula XII and a compound of formula XIV: Preferably, the raw materials of the rubber composition include a compound of formula I and a compound of formula II, or a compound of formula IV and a compound of formula VI, or a compound of formula VIII and a compound of formula X, or a compound of formula XII and a compound of formula XIV.

4. The rubber composition according to claim 3, characterized in that In the raw materials of the rubber composition, the total amount of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1-3 parts by mass, for example, 1.5-2 parts by mass; and / or Among the raw materials of the rubber composition, the mass ratio of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1:2 to 2:1, for example, 1:1.5 to 1.5:

1.

5. The rubber composition according to claim 1, characterized in that The rubber composition has one or more of the following characteristics: The diene elastomer comprises natural rubber and butadiene rubber in a mass ratio of 1:2 to 2:1; The raw materials of the rubber composition also include 30-70 parts by mass of a reinforcing filler; the reinforcing filler is preferably carbon black; The raw materials of the rubber composition also include 0.5-3 parts by mass of sulfur; The raw materials of the rubber composition further include 1-10 parts by mass of an active agent; preferably, the active agent is zinc oxide; The raw materials of the rubber composition also include 2-15 parts by mass of a softener; The raw materials of the rubber composition further include 0.2-2 parts by mass of an accelerator; the accelerator is preferably N-tert-butyl-2-benzothiazole sulfenamide.

6. A rubber product, characterized in that: The rubber product comprises the rubber composition according to any one of claims 1 to 4; preferably, the rubber product is a tire.

7. A method for improving the fatigue aging resistance of a rubber composition, characterized in that: The method comprises: based on 100 parts by mass of the diene elastomer contained in the raw materials of the rubber composition, adding 1 to 3 parts by mass of two or more compounds of formula A to the raw materials of the rubber composition: In formula A, R1, R2 and R3 are each independently selected from C1-C8 alkyl; Preferably, in formula A, R1 and R2 are each independently selected from C1-C3 alkyl, preferably each independently selected from methyl and ethyl; Preferably, in formula A, R3 is selected from C3-C8 alkyl, preferably selected from C3-C6 alkyl, for example selected from C4-C6 alkyl.

8. The method according to claim 7, characterized in that The method comprises: adding two compounds selected from the group consisting of a compound of formula I, a compound of formula II, a compound of formula IV, a compound of formula VI, a compound of formula VIII, a compound of formula X, a compound of formula XII and a compound of formula XIV to the raw materials of the rubber composition: Preferably, the method comprises: adding a compound of formula I and a compound of formula II, or a compound of formula IV and a compound of formula VI, or a compound of formula VIII and a compound of formula X, or a compound of formula XII and a compound of formula XIV to the raw materials of the rubber composition.

9. The method according to claim 8, characterized in that In the raw materials of the rubber composition, the total amount of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1-3 parts by mass, for example, 1.5-2 parts by mass; and / or Among the raw materials of the rubber composition, the mass ratio of two compounds selected from the group consisting of the compound of formula I, the compound of formula II, the compound of formula IV, the compound of formula VI, the compound of formula VIII, the compound of formula X, the compound of formula XII and the compound of formula XIV is 1:2 to 2:1, for example, 1:1.5 to 1.5:

1.

10. The method according to claim 7, characterized in that The method has one or more of the following features: The diene elastomer comprises natural rubber and butadiene rubber in a mass ratio of 1:2 to 2:1; The raw materials of the rubber composition also include 30-70 parts by mass of a reinforcing filler; the reinforcing filler is preferably carbon black; The raw materials of the rubber composition also include 0.5-3 parts by mass of sulfur; The raw materials of the rubber composition further include 1-10 parts by mass of an active agent; preferably, the active agent is zinc oxide; The raw materials of the rubber composition also include 2-15 parts by mass of a softener; The raw materials of the rubber composition further include 0.2-2 parts by mass of an accelerator; the accelerator is preferably N-tert-butyl-2-benzothiazole sulfenamide.

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