Anti-aging agent and application thereof, and solution polymerized styrene-butadiene rubber and preparation method thereof

Abstract

The invention relates to the field of solution polymerized styrene-butadiene rubber, and discloses an anti-aging agent and application thereof, solution polymerized styrene-butadiene rubber and a preparation method thereof. The anti-aging agent contains a compound with a structure shown in a formula (I) and a compound with a structure shown in a formula (II), and in the formula (I) and the formula (II), n is an integer from 1 to 16. By using the anti-aging agent provided by the invention, the aging property of the solution polymerized styrene-butadiene rubber can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of solution-polymerized styrene-butadiene rubber (SBR), specifically to an antioxidant and its application, and solution-polymerized SBR and its preparation method. Background Technology

[0002] The synthesis of solution-polymerized styrene-butadiene rubber (SSBR) primarily employs anionic solution polymerization. For example, SSBR can be synthesized using cyclohexane as a solvent and alkyllithium or rare earth catalysts via anionic solution polymerization. The primary use of SSBR is in tire products, where it is a high-performance tire tread compound. However, SSBR undergoes aging during production and storage, characterized by a gradual increase in Mooney viscosity, eventually rendering it unusable. To slow down the aging process, substances that inhibit aging are added to SSBR, thus maintaining its basic properties after production and storage. These substances are called antioxidants. Antioxidants are diverse, with varying functions. Based on their primary function, they can be categorized as anti-thermal and oxygen aging agents, anti-ozone agents, harmful metal ion inhibitors, anti-fatigue agents, ultraviolet absorbers, and anti-cracking agents. However, since each protective function is often not specific to a single antioxidant, using a single antioxidant often fails to achieve adequate protection.

[0003] CN101575423A discloses a rare earth rubber antioxidant and its application, which provides a rubber antioxidant containing rare earth organometallic compounds or mixtures. However, the use of this rare earth rubber antioxidant introduces metal elements into the final product, which does not meet the actual use requirements of SSBR. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor protective effect of existing antioxidants for solution-polymerized styrene-butadiene rubber (SBR) and the fact that these antioxidants do not meet the actual application requirements of SBR. This invention provides a new antioxidant for preparing SBR that meets the actual application requirements, a method for preparing SBR using this antioxidant, and the SBR obtained by this method. Using the antioxidant of this invention can significantly improve the aging properties of SBR.

[0005] To achieve the above objectives, a first aspect of the present invention provides an antioxidant comprising a compound with the structure shown in formula (I) and a compound with the structure shown in formula (II).

[0006]

[0007] In equation (I), n is an integer from 1 to 16;

[0008]

[0009] In equation (II), n is an integer from 1 to 16.

[0010] Preferably, in formula (I), n is an integer from 4 to 16, and more preferably an integer from 10 to 14.

[0011] Preferably, in formula (II), n is an integer from 4 to 16, and more preferably an integer from 10 to 14.

[0012] Preferably, the molar ratio of the compound with the structure shown in formula (I) to the compound with the structure shown in formula (II) is 0.02-2:1, more preferably 0.5-1.1:1.

[0013] In a second aspect, the present invention provides a method for preparing solution-polymerized styrene-butadiene rubber, the method comprising the following steps:

[0014] 1) Under anionic polymerization conditions, in the presence of an organolithium initiator, styrene monomer and butadiene monomer are polymerized in an inert solvent, and the conversion rate of the polymerized monomer reaches more than 96%.

[0015] 2) Under coupling reaction conditions, the polymerization product obtained in step 1) is reacted with the coupling agent;

[0016] 3) Contact the coupling product obtained in step 2) with the terminator and antioxidant;

[0017] The antioxidant is the antioxidant described in the first aspect of this invention.

[0018] Preferably, the amount of antioxidant is 0.1-0.5 parts by weight, more preferably 0.2-0.4 parts by weight, relative to 100 parts by weight of polymeric monomer.

[0019] Preferably, the organolithium initiator is a compound represented by formula (Ⅲ).

[0020] R3Li type (Ⅲ),

[0021] In formula (Ⅲ), R3 is a C1-C6 alkyl group, C3 ... 12 cycloalkyl, C7-C 14 Aryl or C6-C 12 Aryl groups.

[0022] Preferably, the organolithium initiator is n-butyllithium.

[0023] Preferably, the anionic polymerization conditions include: a polymerization initiation temperature of 30-60°C, a pressure of 0.1-0.3 MPa, and a time of 15-30 min.

[0024] Preferably, the coupling agent is a three-arm coupling agent.

[0025] Preferably, the three-arm coupling agent is one or more of methyltrichlorosilane, ethyltrichlorosilane, and propyltrichlorosilane, with methyltrichlorosilane being the most preferred.

[0026] Preferably, the molar ratio of the coupling agent to the organolithium initiator is 0.1-0.4:1, more preferably 0.2-0.25:1.

[0027] In a third aspect, the present invention provides a solution-polymerized styrene-butadiene rubber, wherein the solution-polymerized styrene-butadiene rubber is prepared by the method described in the second aspect of the present invention.

[0028] In a fourth aspect, the present invention provides the application of the antioxidant described in the first aspect of the present invention in the preparation of solution-polymerized styrene-butadiene rubber.

[0029] Through the above technical solution, the present invention provides a novel antioxidant for preparing solution-polymerized styrene-butadiene rubber (SBR), a method for preparing SBR using this antioxidant, and the SBR obtained by this method. Using the antioxidant of the present invention can significantly improve the aging properties of solution-polymerized SBR. Detailed Implementation

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] In a first aspect, the present invention provides an antioxidant comprising a compound having the structure shown in formula (I) and a compound having the structure shown in formula (II).

[0032]

[0033] In equation (I), n is an integer from 1 to 16;

[0034]

[0035] In equation (II), n is an integer from 1 to 16.

[0036] Preferably, in formula (I), n is an integer from 4 to 16; more preferably, in formula (I), n is an integer from 10 to 14.

[0037] Preferably, in formula (II), n is an integer from 4 to 16; more preferably, in formula (II), n is an integer from 10 to 14.

[0038] In equations (I) and (II), specific examples of n can be given, for example: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 respectively.

[0039] As specific examples of compounds with the structure shown in formula (I), compounds with n ranging from 1 to 16 can be cited.

[0040] As specific examples of compounds with the structure shown in formula (II), compounds with n ranging from 1 to 16 can be cited.

[0041] In a preferred embodiment of the present invention, the antioxidant contains a compound with the structure shown in formula (I) and a compound with the structure shown in formula (II), wherein n = 4 in formulas (I) and (II).

[0042] In another preferred embodiment of the invention, the antioxidant contains a compound with the structure shown in formula (I) and a compound with the structure shown in formula (II), where n = 10 in formulas (I) and (II).

[0043] In another preferred embodiment of the invention, the antioxidant contains a compound with the structure shown in formula (I) and a compound with the structure shown in formula (II), where n = 16 in formulas (I) and (II).

[0044] Furthermore, the compounds with the structures shown in formula (I) and (II) above can be prepared by organic synthesis or obtained commercially.

[0045] According to the present invention, the relative ratio of the compound with the structure shown in formula (I) and the compound with the structure shown in formula (II) in the antioxidant can be appropriately selected according to the specific application. Generally, the molar ratio of the compound with the structure shown in formula (I) to the compound with the structure shown in formula (II) is 0.2-2:1; preferably, the molar ratio of the compound with the structure shown in formula (I) to the compound with the structure shown in formula (II) is 0.5-1.1:1; more preferably, the molar ratio of the compound with the structure shown in formula (I) to the compound with the structure shown in formula (II) is 0.6-1.1:1. Within the above range, the anti-aging performance can be further improved by making the molar ratio of the compound with the structure shown in formula (I) greater than 0.5.

[0046] Specific examples of the molar ratio of compounds with the structure shown in Formula (I) and compounds with the structure shown in Formula (II) include, for example: 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc., as well as any range formed by any two of the above.

[0047] In a second aspect, the present invention provides a method for preparing solution-polymerized styrene-butadiene rubber, the method comprising the following steps:

[0048] 1) Under anionic polymerization conditions, in the presence of an organolithium initiator, styrene monomer and butadiene monomer are polymerized in an inert solvent, and the conversion rate of the polymerized monomer reaches more than 96%.

[0049] 2) Under coupling reaction conditions, the polymerization product obtained in step 1) is reacted with the coupling agent;

[0050] 3) Contact the coupling product obtained in step 2) with the terminator and antioxidant;

[0051] The antioxidant is the antioxidant described in the first aspect of this invention.

[0052] The antioxidant has been described in detail above and will not be repeated here. Furthermore, this invention relates only to improvements in the antioxidant, and there are no particular limitations on the conditions in the above-described method for preparing solution-polymerized styrene-butadiene rubber; these conditions can be implemented according to those known in the art.

[0053] In this invention, the amount of antioxidant can be appropriately selected based on the weight of the polymeric monomers. Generally, relative to 100 parts by weight of the polymeric monomers (the combined amount of styrene and butadiene monomers), the amount of antioxidant is 0.1-0.5 parts by weight, preferably 0.2-0.4 parts by weight, and particularly preferably 0.3 parts by weight. For example, the amount of antioxidant can be 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, etc.

[0054] According to the present invention, the organolithium initiator can be any organolithium monolithium compound, organolithium dilithium compound, or organolithium polylithium compound commonly used in the field of anionic polymerization that can initiate olefin polymerization, without particular limitation. The organolithium initiator is preferably an organolithium monolithium compound, more preferably a compound represented by formula (III).

[0055] R3Li (III)

[0056] In formula (III), R3 is a C1-C6 alkyl group, C3 ... 12 cycloalkyl, C7-C 14 Aryl or C6-C 12 Aryl groups.

[0057] The C1-C6 alkyl groups include straight-chain alkyl groups of C1-C6 and branched alkyl groups of C3-C6, and specific examples may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, and n-hexyl.

[0058] The C3-C 12 Specific examples of cycloalkyl groups may include, but are not limited to: cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-n-propylcyclohexyl, and 4-n-butylcyclohexyl.

[0059] The C7-C 14 Specific examples of aralkyl groups may include, but are not limited to: phenylmethyl, phenylethyl, phenyl-n-propyl, phenyl-n-butyl, phenyl-tert-butyl, phenylisopropyl, phenyl-n-pentyl, and phenyl-n-butyl.

[0060] The C6-C 12 Specific examples of aryl groups may include, but are not limited to: phenyl, naphthyl, 4-methylphenyl and 4-ethylphenyl.

[0061] The organolithium initiator may be, but is not limited to, one or more of the following: ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, phenyl lithium, 2-naphthyl lithium, 4-butylphenyl lithium, 4-tolyl lithium, cyclohexyl lithium, and 4-butylcyclohexyl lithium, preferably n-butyl lithium and / or sec-butyl lithium, and more preferably n-butyl lithium.

[0062] The present invention does not particularly limit the amount of the organolithium initiator, which can be appropriately selected according to the molecular weight and microstructure of the target polymer. Preferably, the amount of the organolithium initiator relative to 100g of polymerizing monomers (the combined amount of styrene and butadiene) can be 0.5-5mmol, more preferably 0.5-2mmol.

[0063] According to the present invention, in step (1), the inert solvent can be any organic substance capable of serving as a reaction medium, for example, it can be a hydrocarbon solvent and / or an ether solvent. The hydrocarbon solvent can be one or more of C5-C7 cycloalkanes, aromatics, and isoalkanes. Specific examples of the hydrocarbon solvent may include, but are not limited to, one or more of benzene, toluene, hexane, cyclohexane, pentane, heptane, hexane, and cyclohexane. The ether solvent can be C4-C... 15The solvents are monoethers and / or polyethers. Specific examples of the ether solvents may include, but are not limited to, tert-butoxyethoxyethane. These solvents can be used alone or in combination. Preferably, the inert solvent is a hydrocarbon solvent, more preferably a combination of cyclohexane and n-hexane, and even more preferably a mixture of cyclohexane and n-hexane in a mass ratio of 7-9:1.

[0064] Furthermore, as is known to those skilled in the art, trace amounts of water may be present in the inert solvent. Water is a terminator in anionic polymerization, capable of terminating chain growth reactions through proton transfer. Therefore, to ensure the smooth progress of the reaction, the present invention preferably removes water from the inert solvent. This removal can be achieved by adding a dehydrating agent to the inert solvent. The types of dehydrating agents are known to those skilled in the art, for example, 5A molecular sieve.

[0065] According to the present invention, preferably, in step 1), the anionic polymerization conditions include: a polymerization initiation temperature of 30-60°C, a pressure of 0.1-0.3 MPa, and a time of 15-30 min.

[0066] In this invention, all pressures refer to gauge pressure.

[0067] According to one embodiment of the present invention, in step 1), the polymerization time can be selected based on the peak reaction temperature (peak temperature) reached. The term "peak reaction temperature" or "peak temperature" refers to the highest temperature reached during the reaction process in each step. In this case, the polymerization time in step 1) can be 10-30 minutes. Typically, after reaching the peak reaction temperature, the monomer conversion rate in the reaction can reach 100% by weight.

[0068] According to the present invention, the polymerization is carried out in an atmosphere formed by an inert gas. The inert gas refers to a gas that does not chemically interact with the reactants, reaction products, and solvent under the polymerization conditions, such as nitrogen and / or Group 0 element gases (e.g., argon).

[0069] According to the present invention, an activator may be added during the anionic polymerization reaction in step (1) to effectively control the microstructure of the polymer product. The activator may be one or more of various existing substances capable of regulating the microstructure of polymers, including oxygen-containing, nitrogen-containing, sulfur-containing, and phosphorus-containing compounds. Specifically, the activator may be selected from one or more of diethyl ether, dibutyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane, crown ether, tetrahydrofurfuryl ethyl ether, triethylamine, tetramethylethylenediamine, hexamethylphosphoric triamine, potassium tert-butoxide, potassium tert-pentoxide, potassium lauryl alcohol, potassium alkylbenzene sulfonate, and sodium alkylbenzene sulfonate. Generally, the molar ratio of the activator to the organic lithium initiator can be 1-100:1, preferably 80-100:1.

[0070] Generally, anionic polymerization systems do not exhibit significant termination or transfer reactions; the active sites remain even after all monomers are consumed. Therefore, the preparation method of this invention may further include contacting the resulting reaction mixture with a terminator after the polymerization reaction is complete, thereby terminating the polymerization reaction and deactivating the active sites. The terminator can be any substance commonly used in anionic polymerization that can terminate active chains, such as water and / or alcohols. The alcohol is preferably a C1-C5 alcohol, such as one or more of methanol, ethanol, n-propanol, and isopropanol. Preferably, the terminator is water.

[0071] According to the present invention, before the polymerization reaction is completed and before the terminating agent is added to terminate the reaction, the method of the present invention further includes contacting the polymerized mixture with a coupling agent to couple the active chains generated during the polymerization reaction.

[0072] According to the present invention, the coupling agent can be any of the various 2-4 functional coupling agents commonly used in the art. For example, a two-armed coupling agent, a three-armed coupling agent, or a four-armed coupling agent can be used.

[0073] As a two-arm coupling agent, dialkyl dihalosilane can be used; preferably, the two-arm coupling agent is dimethyl dichlorosilane.

[0074] Alkyl trihalosilanes can be used as three-arm coupling agents; preferably, the three-arm coupling agent is one or more of methyltrichlorosilane, ethyltrichlorosilane and propyltrichlorosilane; more preferably, the three-arm coupling agent is methyltrichlorosilane.

[0075] As a four-arm coupling agent, silicon tetrachloride, tin tetrachloride, etc. can be used, for example.

[0076] In a particularly preferred embodiment of the present invention, the coupling agent is a three-arm coupling agent. When preparing solution-polymerized styrene-butadiene rubber using a three-arm coupling agent, the aging properties of the solution-polymerized styrene-butadiene rubber can be significantly improved by using the antioxidant of the present invention.

[0077] The amount of coupling agent used is determined so that the coupled polymer can meet the specific application requirements. Generally, the organolithium initiator is based on lithium, and the molar ratio of the coupling agent to the organolithium initiator is preferably 0.1-0.4:1, more preferably 0.2-0.25:1.

[0078] There are no particular limitations on the conditions under which the polymerization product is reacted with the coupling agent; any conventional conditions can be used. Generally, the polymerization product can be reacted with the coupling agent under anionic polymerization conditions.

[0079] According to the present invention, the polymer in the final mixture can be precipitated from the solution by methods such as purification precipitation, centrifugation, filtration, decantation, and hot water coagulation. Alternatively, the solvent in the reaction system can be removed by air stripping. Those skilled in the art will know this, and it will not be described in detail here.

[0080] In a third aspect, the present invention provides a solution-polymerized styrene-butadiene rubber, wherein the solution-polymerized styrene-butadiene rubber is prepared by the method described in the second aspect of the present invention.

[0081] In a fourth aspect, the present invention provides the application of the antioxidant described in the first aspect of the present invention in the preparation of solution-polymerized styrene-butadiene rubber.

[0082] The present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0083] In the following examples and comparative examples, the number-average molecular weight and molecular weight distribution were determined using a gel permeation chromatography (GPC) instrument of model LC-10AT purchased from Shimadzu Corporation, with THF as the mobile phase, narrow-distribution polystyrene as the standard, and the test temperature being 25°C.

[0084] The oxidation induction period (OIT, min) was measured using a DSC 200PC differential scanning calorimeter manufactured by Netzsch GmbH, Germany.

[0085] Mooney viscosity (ML1+4, 100℃) was measured using a Mooney viscometer (model SMV-300) purchased from Shimadzu Corporation, and the test method was performed in accordance with GB / T 1232-92.

[0086] Example 1

[0087] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours).

[0088] Under high-purity nitrogen protection, 195 kg of the above-mentioned mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system concentration 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added (445 mL for initiation + 35 mL for impurity removal) to initiate the polymerization reaction. The polymerization initiation temperature was 50 °C and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90 °C and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0089] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=4, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=4, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.5:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 120,000 and the molecular weight distribution was 1.12.

[0090] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0091] Example 2

[0092] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0093] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=16, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=16, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.5:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 118,000 and the molecular weight distribution was 1.13.

[0094] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0095] Example 3

[0096] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0097] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.5:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 121,000 and the molecular weight distribution was 1.12.

[0098] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0099] Example 4

[0100] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0101] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.6:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 119,000 and the molecular weight distribution was 1.11.

[0102] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0103] Example 5

[0104] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0105] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.7:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 120,000 and the molecular weight distribution was 1.12.

[0106] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0107] Example 6

[0108] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0109] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.8:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 122,000 and the molecular weight distribution was 1.12.

[0110] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0111] Example 7

[0112] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 34 g of bis(tetrahydrofurfuryl) (system content 150 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL of a n-butyllithium n-hexane solution (n-butyllithium concentration 0.6 mol / L) was added (445 mL for initiation + 35 mL for impurity removal) to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0113] At a temperature of 65℃ and a pressure of 0.15MPa, 200 mL of silicon tetrachloride solution (concentration of 0.2 mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8 g of deionized water was added to the polymerization reactor to terminate the reaction. Then, the reaction was stirred for 5 minutes, and then 96 g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 0.9:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 121,000 and the molecular weight distribution was 1.13.

[0114] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0115] Example 8

[0116] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0117] At a temperature of 65℃ and a pressure of 0.15MPa, 200mL of tin tetrachloride solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 1.0:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 122,000 and the molecular weight distribution was 1.12.

[0118] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0119] Example 9

[0120] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system content 3000 ppm) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0121] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration of 0.2mol / L, solvent of the above mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 96g of a composite of antioxidant 1 (a compound with the structure shown in formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) and antioxidant 2 (a compound with the structure shown in formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) (molar ratio of 1.1:1) was added to obtain a gel. The number-average molecular weight and molecular weight distribution of the polymer were determined using the gel. The results showed that the number-average molecular weight was 119,000 and the molecular weight distribution was 1.13.

[0122] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0123] Comparative Example 1

[0124] Before polymerization, a mixed solvent of cyclohexane and n-hexane (weight ratio 88:12) was soaked for one week in 5A molecular sieve (φ3×5, purchased from Dalian Kangyu Chemical Co., Ltd., pre-dried at 500℃ for 5 hours). Under high-purity nitrogen protection, 195 kg of the above mixed solvent, 8 kg of styrene, and 680 g of tetrahydrofuran (system concentration 3000 PPM) were added sequentially to a 500 L polymerization reactor. After the polymerization system was deoxygenated by high-purity N2 replacement, 24 kg of butadiene was added. After stirring for 10 minutes, 480 mL (445 mL for initiation + 35 mL for impurity removal) of a n-butyllithium solution in n-hexane (n-butyllithium concentration 0.6 mol / L) was added to initiate the polymerization reaction. The polymerization initiation temperature was 50℃ and the pressure was 0.1 MPa. After 15 minutes of reaction, the peak temperature (maximum temperature, the same below) reached 90℃ and the peak pressure (maximum pressure, the same below) reached 0.28 MPa. After continuing the reaction for another 5 minutes, a sample was taken and the monomer conversion rate was measured to be 100%.

[0125] At a temperature of 65℃ and a pressure of 0.15MPa, 300mL of methyltrichlorosilane solution (concentration 0.2mol / L, solvent is the above-mentioned mixed solvent) was added to the reactor for coupling reaction. After 15 minutes of coupling reaction, 4.8g of deionized water was added to the polymerization reactor to terminate the reaction. Then, after stirring for 5 minutes, 256g of antioxidant 2,6-di-tert-butyl-p-cresol was added to obtain the polymer solution. The number-average molecular weight and molecular weight distribution of the polymer were determined using the polymer solution. The results showed that the number-average molecular weight was 119,000 and the molecular weight distribution was 1.13.

[0126] The solution was condensed with water vapor and dried on a two-roll mill to obtain solution-polymerized styrene-butadiene rubber (SBR) products. The aging test data of the products are shown in Table 1.

[0127] Comparative Example 2

[0128] The process was carried out according to Example 3, except that only 96g of antioxidant 1 (a compound with the structure shown in Formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) was added to obtain solution-polymerized styrene-butadiene rubber product. The aging test data of the product are shown in Table 1.

[0129] Comparative Example 3

[0130] The process was carried out according to Example 3, except that only 96g of antioxidant 2 (a compound with the structure shown in Formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) was added to obtain solution-polymerized styrene-butadiene rubber product. The aging test data of the product are shown in Table 1.

[0131] Comparative Example 4

[0132] The process was carried out according to Example 3, except that only 256g of antioxidant 1 (a compound with the structure shown in Formula (I), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) was added to obtain solution-polymerized styrene-butadiene rubber product. The aging test data of the product are shown in Table 1.

[0133] Comparative Example 5

[0134] The process was carried out according to Example 3, except that only 256g of antioxidant 2 (a compound with the structure shown in Formula (II), n=10, purchased from Beijing Jiyi Chemical Co., Ltd.) was added to obtain solution-polymerized styrene-butadiene rubber product. The aging test data of the product are shown in Table 1.

[0135] Table 1

[0136] Example No. S1 S2 S3 S4 S5 S6 S7 S8 S9 DS1 DS2 DS3 DS4 DS5 Oxidation induction period, min 45 46 50 56 61 76 81 85 92 25 40 35 85 80 ML1+4, 100℃ 53 52 49 50 50 52 49 51 51 63 65 67 60 61

[0137] Note: The oxidation induction period test temperature was 140℃.

[0138] As shown in Table 1 above, Examples S1-S3 use the same design ratio of the antioxidant of the present invention, with an addition amount of 0.3 parts by weight relative to 100 parts by weight of the polymer monomer; Examples S3-S9 use antioxidants of the present invention with different design ratios, with an addition amount of 0.3 parts by weight relative to 100 parts by weight of the polymer monomer; Comparative Example DS1 uses a conventional antioxidant, with an addition amount of 0.8 parts by weight relative to 100 parts by weight of the polymer monomer; Comparative Example DS2 uses only the compound shown in Formula (I), with an addition amount of 0.3 parts by weight relative to 100 parts by weight of the polymer monomer; Comparative Example DS3 uses only the compound shown in Formula (II), with an addition amount of 0.3 parts by weight relative to 100 parts by weight of the polymer monomer; Comparative Example DS4 uses only the compound shown in Formula (I), with an addition amount of 0.8 parts by weight relative to 100 parts by weight of the polymer monomer; Comparative Example DS5 uses only the compound shown in Formula (II), with an addition amount of 0.8 parts by weight relative to 100 parts by weight of the polymer monomer. Data shows that, with reduced dosage, the oxidation induction period of the antioxidant of this invention is significantly better than that of traditional antioxidants, compounds using the structure shown in formula (I) alone, and compounds using the structure shown in formula (II) alone. Furthermore, traditional antioxidants, compounds using the structure shown in formula (I) alone, and compounds using the structure shown in formula (II) alone exhibit an increase in Mooney viscosity during the drying process. Therefore, it can be concluded that the antioxidant of this invention has a significant effect on resisting thermo-oxidative aging.

[0139] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An antioxidant, characterized in that, This antioxidant contains compounds with the structure shown in formula (I) and compounds with the structure shown in formula (II). In equation (I), n is an integer from 1 to 16; In equation (II), n is an integer from 1 to 16.

2. The antioxidant according to claim 1, wherein, In formula (I), n is an integer from 4 to 16, preferably an integer from 10 to 14.

3. The antioxidant according to claim 1, wherein, In equation (II), n is an integer from 4 to 16, preferably an integer from 10 to 14.

4. The structural anti-aging agent according to any one of claims 1-3, wherein, The molar ratio of the compound with the structure shown in formula (I) to the compound with the structure shown in formula (II) is 0.02-2:1, preferably 0.5-1.1:

1.

5. A method for preparing solution-polymerized styrene-butadiene rubber, the method comprising the following steps: 1) Under anionic polymerization conditions, in the presence of an organolithium initiator, styrene monomer and butadiene monomer are polymerized in an inert solvent, and the conversion rate of the polymerized monomer reaches more than 96%. 2) Under coupling reaction conditions, the polymerization product obtained in step 1) is reacted with the coupling agent; 3) Contact the coupling product obtained in step 2) with the terminator and antioxidant; The antioxidant is characterized in that it is the antioxidant described in any one of claims 1-4.

6. The method according to claim 5, wherein, The amount of antioxidant used is 0.1-0.5 parts by weight, preferably 0.2-0.4 parts by weight, relative to 100 parts by weight of polymeric monomer.

7. The method according to claim 5, wherein, The organolithium initiator is a compound represented by formula (Ⅲ). R3Li type (Ⅲ), In formula (Ⅲ), R3 is a C1-C6 alkyl group, C3 ... 12 cycloalkyl, C7-C 14 Aryl or C6-C 12 aryl; Preferably, the organolithium initiator is n-butyllithium.

8. The method according to any one of claims 5-7, wherein, The anionic polymerization conditions include: a polymerization initiation temperature of 30-60℃, a pressure of 0.1-0.3MPa, and a time of 15-30min.

9. The method according to any one of claims 5-7, wherein, The coupling agent is a three-armed coupling agent; Preferably, the three-arm coupling agent is one or more of methyltrichlorosilane, ethyltrichlorosilane, and propyltrichlorosilane, with methyltrichlorosilane being the most preferred.

10. The method according to any one of claims 5-7, wherein, The molar ratio of the coupling agent to the organolithium initiator is 0.1-0.4:1, preferably 0.2-0.25:

1.

11. A solution-polymerized styrene-butadiene rubber, characterized in that, The solution-polymerized styrene-butadiene rubber is prepared by the method described in any one of claims 5-10.

12. The use of the antioxidant according to any one of claims 1-4 in the preparation of solution-polymerized styrene-butadiene rubber.

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