Compound for Rubber and Rubber Composition

Abstract

To provide a rubber compounding ingredient containing an organosilicon compound, which can be added to a rubber composition, enabling the rubber composition to achieve desired fuel economy and abrasion resistance while maintaining processability of the composition as well as hardness and tensile properties of its cured product.SOLUTION: A rubber compounding ingredient contains (A) a compound having a blocked isocyanate group and a hydrolyzable silyl group, such as an organosilicon compound represented by the following formula (1) where R1 is each independently an alkyl group having 1 to 8 carbon atoms, L is a divalent linking group, X is -O- or -NR2-, Z is a hydrogen atom or a monovalent organic group, R2 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a group capable of bonding to Z to form a ring structure, and m is an integer of 1 to 3.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rubber compounding agent containing an organosilicon compound and a rubber composition.

Background Art

[0002] Silica-filled tires have excellent performance in automotive applications, especially in terms of abrasion resistance, rolling resistance, and wet grip performance. The improvement of these performances is closely related to the improvement of the low fuel consumption of tires. Therefore, it has been actively studied in the industry of passenger car tires using solution-polymerized styrene-butadiene rubber (S-SBR) in recent years.

[0003] Although silica-filled rubber compositions reduce the rolling resistance of tires and improve wet grip performance, they have high unvulcanized viscosity, require multi-stage kneading, etc., and have problems in workability. Therefore, in a rubber composition simply blended with an inorganic filler such as silica, problems such as insufficient dispersion of the filler and a significant decrease in breaking strength and abrasion resistance occur. Therefore, a sulfur-containing organosilicon compound is essential to improve the dispersibility of the inorganic filler in the rubber and to chemically bond the filler and the rubber matrix.

[0004] As the sulfur-containing organosilicon compound used as a rubber compounding agent, compounds containing an alkoxysilyl group and a polysulfidosilyl group in the molecule, such as bis-triethoxysilylpropyltetrasulfide and bis-triethoxysilylpropyldisulfide, are known to be effective (see Patent Documents 1 to 4).

[0005] In addition, high load-bearing tires mounted on trucks, buses, etc. are required to have high fracture resistance so as to withstand use under severe conditions. Natural rubber is used as the rubber, but in such tires as well, the demand for improving low fuel consumption and abrasion resistance is increasing (Patent Document 5).

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-525230 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2004-18511 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2002-145890 [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2000-103795 [Patent Document 5] Japanese Unexamined Patent Application Publication No. 2019-131649 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] The present invention has been made in view of the above circumstances, and when added to a rubber composition, it provides a rubber composition containing an organosilicon compound that can achieve desired low fuel consumption performance and wear resistance while maintaining the processability of the composition, the hardness of its cured product, and its tensile properties, a rubber composition compounded with this rubber compounding agent, and a tire formed from this rubber composition. [Means for Solving the Problems]

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that a predetermined organosilicon compound having a blocked isocyanate group and a hydrolyzable silyl group is suitable as a rubber compounding agent, and have found that a tire obtained from a rubber composition containing this rubber compounding agent can achieve desired low fuel consumption performance and wear resistance while maintaining hardness and tensile properties, thereby completing the present invention.

[0009] That is, the present invention provides: 1. A rubber compounding agent containing a compound having a blocked isocyanate group and a hydrolyzable silyl group; 2. The rubber compounding agent according to 1 above, wherein the component (A) is an organosilicon compound represented by the following formula (1); [Chemical formula] (In the formula, R 1 each independently represents an alkyl group having 1 to 8 carbon atoms, L represents a divalent linking group, X represents -O- or -NR 2 -, Z represents a hydrogen atom or a monovalent organic group, and R 2 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a group capable of bonding with Z to form a ring structure, and m represents an integer of 1 to 3.) 3. The rubber compounding agent according to claim 2, wherein the component (A) is an organosilicon compound represented by the following formula (2): [Chemical formula] (In the formula, R 1 , R 2 , Z and m are the same as defined above.) 4. The rubber compounding agent according to any one of claims 1 to 3, further containing an organosilicon compound having at least one selected from a polysulfide group, a thioester group, and a mercapto group and an alkoxysilyl group. 5. A rubber composition containing the rubber compounding agent according to any one of claims 1 to 4. 6. The rubber composition according to claim 5, further containing (C) a diene rubber and (D) a filler. 7. A tire formed by molding the rubber composition according to claim 5 or 6. is provided. [Advantages of the Invention]

[0010] The rubber composition containing the rubber compounding agent of the present invention is excellent in processability, and the tire formed using this rubber composition can satisfy the desired low fuel consumption tire characteristics and wear resistance while maintaining the hardness and tensile properties. [Embodiments for Carrying Out the Invention]

[0011] Hereinafter, the present invention will be specifically described. [Rubber compounding agent] The compounding agent for rubber of the present invention contains the following component (A).

[0012] [1] Component (A) Component (A) is a compound having a blocked isocyanate group and a hydrolyzable silyl group, and contains a blocked isocyanate group in which the isocyanate group is blocked by a blocking agent and a hydrolyzable silyl group such as a trimethoxysilyl group or a triethoxysilyl group.

[0013] Component (A) is preferably an organosilicon compound represented by the following formula (1).

Chemical formula

[0014] In formula (1), R 1 each independently represents an alkyl group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, L represents a divalent linking group, X represents -O- or -NR 2 -, Z represents a hydrogen atom or a monovalent organic group, R 2 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a group capable of forming a ring structure by bonding with Z, and m represents an integer of 1 to 3, preferably 3.

[0015] R 1 The alkyl group having 1 to 8 carbon atoms of may be linear, branched or cyclic. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl groups, etc. Among these, R 1 is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group.

[0016] Specific examples of the divalent linking group of L include those composed of an alkylene group, -O-, -S-, -NR-, -C(=O)-, -C(=O)-O-, -NRCO-, -SO2- and combinations thereof. Here, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and a hydrogen atom is preferred. As the alkyl group, those having 1 to 4 carbon atoms among the alkyl groups exemplified above can be mentioned. Among these, as the divalent linking group of L, from the availability of raw materials in the production of organosilicon compounds, -(CH2) n -(n is an integer of 1 to 10, preferably 1 to 6, more preferably 1 to 4). The alkylene group represented by, or this -(CH2) n - in which one or more methylene units are substituted with -O-, -S-, -NH-, -C(=O)- and -C(=O)O- are preferred, and -(CH2)3- (trimethylene group) is more preferred.

[0017] X in formula (1) is -O- or -NR 2 -, but it is a group that forms part of the protecting group of the blocked isocyanate silane compound and is not particularly limited because it is eliminated by heating. For -NR 2 - of X, R 2 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a group capable of bonding with Z to form a ring structure. For R 2 the alkyl group having 1 to 8 carbon atoms, the same groups as those exemplified for R 1 above can be mentioned, but among them, a linear or branched alkyl group having 1 to 5 carbon atoms is preferred, and a methyl group or an ethyl group is more preferred. For -NR 2 - when R 2 represents a group capable of bonding with Z to form a ring structure, -NR 2 - is in formula (1) ZThose that form a heterocyclic structure are preferred. As the heteroatom in such a heterocyclic structure, it is preferable to contain two or more nitrogen atoms, and more preferably to contain two nitrogen atoms. As the heterocyclic structure, a 5-membered ring or 6-membered ring structure is preferred, and a 5-membered ring structure is more preferred.

[0018] Z in formula (1) is a hydrogen atom or a monovalent organic group, but is a group that forms part of the protecting group of the blocked isocyanate silane compound and is not particularly limited because it is eliminated by heating. Specific examples of the monovalent organic group of Z may have a substituent and may contain an ether bond or an ester bond (however, excluding those containing O at the bonding terminal with an oxygen atom and generating an -O-O- bond), a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydroxyl group (however, excluding the case where X is -O-), -N=R 5 (R 5 represents an alkylidene group having 1 to 10 carbon atoms which may be substituted with an aryl group or a heteroaryl group having 6 to 20 carbon atoms.) and the like can be mentioned. The above monovalent hydrocarbon group having 1 to 20 carbon atoms may be linear, branched or cyclic, and examples thereof include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. Specific examples of the above alkyl group include, in addition to the groups exemplified by R 1 n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-icosyl group and the like can be mentioned. Specific examples of the above aryl group include phenyl, naphthyl group and the like. Specific examples of the above aralkyl group include benzyl, phenylethyl group and the like. In addition, at least a part of the hydrogen atoms of these groups may be substituted with other substituents, and examples of the other substituents include a carboxyl group, a hydroxyl group, an oxo group (=O), a thioxo group (=S) and the like. In the above formula -N=R 5 wherein, R 5Examples of the C1-C10 alkylidene group which may be substituted with an aryl group or heteroaryl group having 6 to 20 carbon atoms include linear, branched, and cyclic ones. Specific examples thereof include methylidene, ethylidene, propylidene, propane-2-ylidene, butylidene, butane-2-ylidene, pentylidene, 4-methylpentane-2-ylidene, hexylidene, cyclohexylidene, heptylidene, octylidene, nonylidene, decylidene groups, and the like. Specific examples of the aryl group having 6 to 20 carbon atoms include the same groups as those exemplified for the monovalent hydrocarbon group above. Specific examples of the heteroaryl group having 6 to 20 carbon atoms include pyrrol-1-yl, 1H-pyrrol-2-yl, imidazol-1-yl, imidazol-2-yl, pyrazol-1-yl, pyrazol-3-yl, pyridin-2-yl, pyridin-3-yl groups, and the like. Specific examples of the substituted alkylidene group include phenylmethylene, diphenylmethylene groups, and the like.

[0019] Component (A) is particularly preferably represented by the following formula (2).

[0020] [Chemical formula] (In the formula, R 1 , R 2 , Z and m are the same as defined above.)

[0021] R 2 and specific examples of Z are the same as above. Among them, it is preferable that these are bonded to each other to form a ring structure together with the nitrogen atom to which R 2 and Z are bonded. Specific examples of the ring structure include an imidazole ring, a pyrazole ring, a 1,2,3-triazole ring, and a 1,2,4-triazole ring, with a pyrazole ring being more preferable. The above ring structure may have substituents such as an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a carboxyl group, a hydroxyl group, an ester group, an oxo group (=O), a halogen group such as chlorine and bromine, and a nitro group. Preferable ring structures include, but are not limited to, the following.

[0022]

Chemical formula

[0023] Preferable specific examples of component (A) include, but are not limited to, the following compounds. Component (A) may be used alone or in combination of two or more.

[0024]

Chemical formula

[0025] The production method of component (A) is not particularly limited, but a method of reacting a compound having an isocyanate group and a hydrolyzable silyl group in one molecule with a blocking agent is preferable. As the compound having an isocyanate group and a hydrolyzable silyl group in one molecule, for example, a compound represented by the following formula (3) can be used.

[0026]

Chemical formula

[0027] Specific examples of the compound represented by the formula (3) include, for example, 1-isocyanatomethyltrimethoxysilane, 1-isocyanatomethyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 6-isocyanatohexyltrimethoxysilane, 6-isocyanatohexyltriethoxysilane, 8-isocyanatooctyltrimethoxysilane, 8-isocyanatooctyltriethoxysilane and the like.

[0028] As the blocking agent, any conventionally known one can be used. For example, those represented by the following formula (4) can be used. [Chemical formula] (In the formula, X and Z are the same as above.)

[0029] Specific examples of the compound represented by the formula (4) include, for example, oxime compounds such as acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, cyclohexanone oxime, benzophenone oxime, etc.; phenolic compounds such as phenol, para-tert-butylphenol, cresol, etc.; alcohol compounds such as n-butanol, 2-ethylhexanol, phenyl carbinol, methyl phenyl carbinol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, methoxy methanol, etc.; lactam compounds such as ε-caprolactam, γ-butyrolactam, etc.; pyrrole compounds such as pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, N-methylpyrrole, etc.; indole compounds such as indole, N-methylindole, 2-methylindole, etc., pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-benzyl-3,5-dimethylpyrazole, methyl-5-methylpyrazole-3-carboxylate, 3-methyl-5-phenylpyrazole, 3,5-dimethylpyrazole-4-carboxyanilide and other pyrazole compounds; acid amide compounds such as acetanilide, acetanisidide, acetotoluidide, acrylamide, methacrylamide, acetic acid amide, stearic acid amide, benzamide, etc.; imide compounds such as succinimide, phthalimide, maleimide, etc.; amine compounds such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, butylphenylamine, etc.; imidazole compounds such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, benzimidazole, etc.; triazole compounds such as 1,2,3-triazole, 1,2,4-triazole, 1,2,3-benzotriazole, etc.; piperidine compounds such as piperidine, N-methylpiperidine, 4-methylpiperidine, etc.;Urea compounds such as urea, thiourea, ethylene urea, ethylene thiourea, diphenyl urea; carbamate compounds such as phenyl N-phenylcarbamate; imine compounds such as ethyleneimine and propyleneimine, etc. can be mentioned. In addition to the above compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, diisopropyl malonate, ethyl acetoacetate, isopropyl acetoacetate, methyl acetoacetate, isopropyl acetoacetate, acetylacetone; mercaptan compounds such as n-butyl mercaptan, tert-butyl mercaptan, n-hexyl mercaptan, tert-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol, ethylthiophenol; sulfite compounds such as sodium bisulfite and potassium bisulfite can also be used. These may be used alone or in combination of two or more. Among these, as the blocking agent, lactam compounds, pyrazole compounds, pyrrole compounds, indole compounds, imidazole compounds, triazole compounds, and piperidine compounds are preferred, and the following compounds are more preferred.

[0030] [Chemical formula]

[0031] The reaction between the compound having an isocyanate group and a hydrolyzable silyl group in one molecule and the blocking agent is preferably carried out in air or in an inert gas atmosphere such as nitrogen or argon, and the blocking agent is used in a ratio of 0.1 to 5 mol, more preferably 0.5 to 3 mol, per 1 mol of the compound having an isocyanate group and a hydrolyzable silyl group in one molecule. The reaction temperature is not particularly limited, but is preferably 50 to 150 °C, more preferably 60 to 120 °C. The reaction time is also not particularly limited, but is preferably 1 to 10 hours, more preferably 2 to 6 hours.

[0032] [2] Component (B) In the compounding agent for rubber of the present invention, in addition to the above component (A), an organosilicon compound having at least one selected from the group consisting of (B) a polysulfide group, a thioester group, and a mercapto group and an alkoxysilyl group can be used. As the component (B), there is no particular limitation as long as it is a compound having such a functional group. For example, any conventionally known silane coupling agent blended in a rubber composition for applications such as tires can be used.

[0033] Specific examples of the above silane coupling agent include polysulfide-based organosilicon compounds such as bis-(3-bis(triethoxysilyl)propyl)-tetrasulfide and bis-(3-bis(triethoxysilyl)propyl)-disulfide; mercapto-based organosilicon compounds such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; thioester-based organosilicon compounds such as 3-octanoylthiopropyltriethoxysilane and 3-propionylthiopropyltrimethoxysilane, and the like. In addition, a reaction product of the above organosilicon compound having a sulfur atom and an alcohol containing a polyether group, a hydrolysis condensate of these organosilicon compounds, a co-hydrolysis condensate of these organosilicon compounds and other organosilicon compounds having an alkoxysilyl group, and the like can also be used. The component (B) may be used alone or in combination of two or more.

[0034] In the compounding agent for rubber of the present invention, when the component (B) is blended, the blending ratio of the above component (A) and component (B) is not particularly limited, but in terms of mass ratio, (B) / (A) = 10 / 90 to 95 / 5 is preferable, and 50 / 50 to 95 / 5 is more preferable.

[0035] At least one kind of powder may be added to the compounding agent for rubber of the present invention. Specific examples of the powder include carbon black, talc, calcium carbonate, stearic acid, silica, aluminum hydroxide, alumina, magnesium hydroxide, and the like. Among these, from the viewpoint of reinforcement, silica and aluminum hydroxide are preferred, and silica is more preferred.

[0036] When blending the powder, considering the handleability of the rubber compounding agent, transportation cost, etc., the blending amount is based on the mass ratio ((X) / (Y)) of the total amount (X) of the above component (A) or components (A) and (B) to the total amount of powder (Y), and 70 / 30 to 5 / 95 is preferred, and 60 / 40 to 10 / 90 is more preferred.

[0037] In addition, the rubber compounding agent of the present invention may be a mixture with organic polymers such as fatty acids, fatty acid salts, polyethylene, polypropylene, polyoxyalkylene, polyester, polyurethane, polystyrene, polybutadiene, polyisoprene, natural rubber, styrene-butadiene copolymer, etc. and rubber, and may also be a mixture containing various additives commonly used for tires and other general rubbers such as vulcanizing agents, crosslinking agents, vulcanization accelerators, crosslinking accelerators, various oils, antioxidants, fillers, plasticizers, etc. Also, as its form, it may be liquid, solid, further diluted with an organic solvent, or emulsified.

[0038] [Rubber composition] The rubber composition of the present invention contains the above-mentioned rubber compounding agent. Preferably, it contains the above-mentioned component (A) or components (A) and (B), (C) diene rubber, and (D) filler. Considering the physical properties of the resulting rubber, the balance between the degree of the effects exerted and economy, etc., the blending amount of component (A) or components (A) and (B) in the rubber composition of the present invention is preferably 3 to 30 parts by mass, and more preferably 5 to 20 parts by mass, based on 100 parts by mass of component (D) described in detail later.

[0039] [3] Component (C) As the diene rubber of component (C), any rubber generally used in various rubber compositions can be used conventionally. Specific examples thereof include various isoprene rubbers (IR) such as natural rubber, various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), and diene rubbers such as acrylonitrile-butadiene copolymer rubber (NBR). These may be used alone or in combination of two or more.

[0040] In particular, component (C) preferably contains natural rubber, and the content of natural rubber in component (C) is preferably 50% by mass or more, more preferably 70 to 100% by mass, from the viewpoint that sufficient fracture resistance characteristics can be obtained even when used as a tire for high-load vehicles. As the natural rubber, those generally used in the tire industry such as RSS#3, SIR20, and TSR20 can be used. Also, modified natural rubbers such as epoxidized natural rubber, hydrogenated natural rubber, grafted natural rubber, and deproteinized natural rubber can be used.

[0041] In addition to the diene rubber, non-diene rubbers such as butyl rubber (IIR) and ethylene-propylene copolymer rubber (EPR, EPDM) may be used in combination.

[0042] [4] Component (D) Examples of the filler for component (D) include fillers generally used in the tire industry such as silica, carbon black, aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, talc, and clay. These may be used alone or in combination of two or more. Among these, it is preferable to contain silica and carbon black, and it is more preferable to contain only silica and carbon black.

[0043] Examples of the carbon black include those generally used in the tire industry such as GPF, FEF, HAF, ISAF, and SAF. Examples of the silica include those commonly used in the tire industry, such as silica prepared by a dry method (anhydrous silica) and silica prepared by a wet method (hydrous silica). Among them, silica prepared by a wet method is preferred because it has many silanol groups. In particular, the silica preferably has a nitrogen adsorption specific surface area (N2SA) of 70 m 2 / g or more, more preferably 100 m 2 / g or more. The upper limit of N2SA is not particularly limited, but from the viewpoint of ease of handling, etc., it is preferably 500 m 2 / g or less, more preferably 400 m 2 / g or less.

[0044] When the component (D) is blended into the rubber composition of the present invention, the blending amount is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and even more preferably 20 to 130 parts by mass with respect to 100 parts by mass of the component (C) from the viewpoints of dispersibility, low fuel consumption property, and moldability. When the rubber compounding agent contains a powder, the above blending amount is the total amount with the powder.

[0045] In addition to the components (A) to (D) described above, various additives generally blended for tires, such as sulfur, crosslinking agents, vulcanization accelerators, crosslinking accelerators, various oils, anti-aging agents, plasticizers, various resins, waxes, zinc oxide, and other additives generally blended for rubbers can be blended into the rubber composition of the present invention. The blending amounts of these additives can be the conventional general blending amounts as long as they do not contravene the object of the present invention.

[0046] Examples of the sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. These may be used alone or in combination of two or more. For example, products available from Kanzaki Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0047] When sulfur is compounded, the compounding amount is preferably 0.1 part by mass or more and 5.0 parts by mass or less, more preferably 0.3 part by mass or more and 2.0 parts by mass or less, and still more preferably 0.5 part by mass or more and 1.5 parts by mass or less with respect to 100 parts by mass of the component (C). When it is within the above range, the balance between tensile properties and abrasion resistance is good.

[0048] [Rubber Product (Tire)] The rubber composition of the present invention can be used for the production of rubber products such as tires, for example, by forming the above-described components (A) to (D) and other components into a composition by a general method and then vulcanizing or crosslinking it. In particular, when manufacturing a tire, it is preferable that the rubber composition of the present invention is used for the tread. The tire obtained by using the rubber composition of the present invention can achieve desired low fuel consumption because, in addition to reducing rolling resistance, its abrasion resistance is improved. In addition, the structure of the tire can be a conventionally known structure, and its manufacturing method may also adopt a conventionally known manufacturing method. Further, in the case of a pneumatic tire, as the gas filled in the tire, usually, in addition to air and air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used.

Examples

[0049] Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to these examples. In the following examples, Me represents a methyl group and Et represents an ethyl group.

[0050] [1] Synthesis of Organosilicon Compound [Synthesis Example 1-1] After placing 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 68 g (1.0 mol) of imidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Then, by performing a filtration step, an organosilicon compound (A-1) represented by the following formula was obtained.

[0051] [Chemical formula]

[0052] [Synthesis Example 1-2] After placing 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 82 g (1.0 mol) of 2-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Then, by performing a filtration step, an organosilicon compound (A-2) represented by the following formula was obtained.

[0053] [Chemical formula]

[0054] [Synthesis Example 1-3] After placing 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 222 g (1.0 mol) of 2-undecylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Then, by performing a filtration step, an organosilicon compound (A-3) represented by the following formula was obtained.

[0055] [Chemical formula]

[0056] [Synthesis Example 1-4] A 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer was charged with 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 96 g (1.0 mol) of 3,5-dimethylpyrazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80 °C, and the mixture was aged at 80 °C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-4) represented by the following formula was obtained.

[0057] [Chemical formula]

[0058] [Synthesis Example 1-5] A 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer was charged with 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 119 g (1.0 mol) of 1,2,3-benzotriazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80 °C, and the mixture was aged at 80 °C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-5) represented by the following formula was obtained.

[0059] [Chemical formula]

[0060] [Synthesis Example 1-6] A 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer was charged with 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 69 g (1.0 mol) of 1,2,4-triazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80 °C, and the mixture was aged at 80 °C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-6) represented by the following formula was obtained.

[0061] [Chemical formula]

[0062] [Synthesis Example 1-7] After placing 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 113 g (1.0 mol) of ε-caprolactam (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Then, by performing a filtration step, an organosilicon compound (A-7) represented by the following formula was obtained.

[0063] [Chemical Formula]

[0064] [Synthesis Example 1-8] 539 g (1.0 mol) of bis(triethoxysilylpropyl)tetrasulfide (KBE-846, manufactured by Shin-Etsu Chemical Co., Ltd.), 222 g (0.8 mol) of octyltriethoxysilane (KBE-3083, manufactured by Shin-Etsu Chemical Co., Ltd.), and 200 g of ethanol were placed in a 1 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer. Then, 25.2 g (1.4 mol of water) of 0.5N hydrochloric acid was added dropwise at room temperature. Next, stirring was carried out at 80°C for 10 hours. Then, 3.0 g of propylene oxide was added dropwise, and stirring was carried out at 80°C for 2 hours. Further, by concentration under reduced pressure and filtration, an organopolysiloxane (B-2) in the form of a brown transparent liquid represented by the following average composition formula with a kinematic viscosity of 80 mm 2 / s was obtained. (-C3H6-S4-C3H6-) 0.36 (-C8H 17 ) 0.28 (-OC2H5) 2.00 SiO 0.50 ···(B-2)

[0065] [2] Production of Rubber Compounding Agents [Examples 1-1 to 1-9] Using a 200 mL separable flask equipped with a stirrer, each component was mixed in the compounding amounts (parts by mass) shown in Table 1 to obtain a rubber compounding agent.

[0066]

Table 1

[0067] [3] Production of rubber composition [Examples 2-1 to 2-9, Comparative Examples 2-1, 2-2] Using a 4 L internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.), the natural rubber described in Tables 2 and 3 was kneaded for 60 seconds. Next, the natural rubber, carbon black, silica, rubber compounding agent obtained in Examples 1-1 to 1-9, stearic acid, antioxidant, resin, and wax described in Tables 2 and 3 were added, and the internal temperature was raised to 150 °C and then discharged. Thereafter, it was stretched using a roll. The obtained rubber composition was kneaded again using an internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.) until the internal temperature reached 145 °C, discharged, and then stretched using a roll. Zinc oxide, vulcanization accelerator, and sulfur described in Tables 2 and 3 were added thereto and kneaded to obtain a rubber composition.

[0068] Natural rubber: RSS#3 Carbon black: Seast 9H (manufactured by Tokai Carbon Co., Ltd.) Silica: Nipsil AQ (manufactured by Tosoh Silica Corporation) Stearic acid: Industrial stearic acid (manufactured by Kao Corporation) Antioxidant: Nocrack 6C (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) Resin: T-REZ RA-100 (manufactured by ENEOS Corporation) Wax: Oz Ace 0355 (manufactured by Nippon Seiro Co., Ltd.) Zinc oxide: Zinc white No. 3 (manufactured by Mitsui Mining & Smelting Co., Ltd.) Vulcanization accelerator (a): Noxeller DM-P (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) Vulcanization accelerator (b): Nocceler CZ-G (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Sulfur: 5% oil-treated sulfur (manufactured by Hosoi Chemical Industry Co., Ltd.)

[0069] For the rubber compositions obtained in Examples 2-1 to 2-9 and Comparative Examples 2-1 and 2-2, the unvulcanized physical properties and vulcanized physical properties were measured by the following methods. The results are shown together in Tables 2 and 3. Regarding the vulcanized physical properties, the obtained rubber composition was press-molded (145 °C, 30 minutes) to produce a vulcanized rubber sheet (thickness 2 mm).

[0070] 〔Unvulcanized physical properties〕 (1) Mooney viscosity In accordance with JIS K 6300-1:2013, afterheat for 1 minute, measurement for 4 minutes, and measurement at a temperature of 130 °C, and expressed as an index with Comparative Example 2-1 as 100. The smaller the index value, the lower the Mooney viscosity and the better the processability. 〔Vulcanized physical properties〕 (2) Hardness The durometer (type A) hardness was measured in accordance with JIS K 6253-3:2012 and expressed as an index with Comparative Example 2-1 as 100. (3) Tensile properties A JIS No. 3 dumbbell-shaped test piece was punched out, and a tensile test was carried out at a tensile speed of 500 mm / min in accordance with JIS K6251, and the 300% modulus (M 300 ) [MPa] was measured at room temperature. The obtained results were expressed as an index with Comparative Example 2-1 as 100. The larger the index value, the higher the modulus and the better the tensile properties. (4) Dynamic viscoelasticity (strain dispersion) Using a viscoelasticity measuring device (manufactured by Metravib), the storage modulus E’(0.5%) at a strain of 0.5% and the storage modulus E’(3.0%) at a strain of 3.0% were measured under the conditions of a temperature of 25 °C and a frequency of 55 Hz, and the value of [E’(0.5%) - E’(3.0%)] was calculated. The test piece used was a sheet with a thickness of 0.2 cm and a width of 0.5 cm, and the initial load was 1 N with a distance between the used clamps of 2 cm. The value of [E’(0.5%) - E’(3.0%)] was expressed as an index with Comparative Example 2-1 as 100. The smaller the index value, the better the dispersibility of silica. (5) Dynamic viscoelasticity (temperature dispersion) Using a viscoelasticity measuring device (manufactured by Metravib), measurements were taken under the conditions of a dynamic strain of 1% in tension and a frequency of 55 Hz. The test piece used was a sheet with a thickness of 0.2 cm and a width of 0.5 cm, and the initial load was set to 1 N with a distance between the used clamps of 2 cm. The value of tanδ(60 °C) was expressed as an index with Comparative Example 2-1 set to 100. The smaller the index value of tanδ(60 °C), the better the rolling resistance. (6) Abrasion resistance Using an FPS tester (manufactured by Ueshima Seisakusho Co., Ltd.), tests were conducted under the conditions of a sample speed of 200 m / min, a load of 20 N, a road surface temperature of 30 °C, a slip ratio of 5% and a slip ratio of 20%. The obtained results were expressed as an index with Comparative Example 2-1 set to 100. The larger the index value, the less the wear amount, indicating excellent abrasion resistance.

[0071]

Table 2

[0072]

Table 3

[0073] As shown in Table 2 and Table 3, the vulcanizates of the rubber compositions of Examples 2-1 to 2-9 maintained their hardness and tensile properties while having lower dynamic viscoelasticity, that is, smaller hysteresis loss and low heat generation, compared to the vulcanizates of the rubber compositions of Comparative Examples 2-1 and 2-2, and also showed excellent abrasion resistance.

Claims

1. A rubber compounding agent containing (A) an organosilicon compound represented by the following formula (1) and (B) one or more selected from a polysulfide group, a thioester group, and a mercapto group, and an organosilicon compound having an alkoxysilyl group. 【Chemical Formula 1】 (In the formula, R 1 each independently represents an alkyl group having 1 to 8 carbon atoms, and L represents a divalent linking group. X represents -O-, and Z represents -N=R 5 (R 5 represents an alkylidene group having 1 to 10 carbon atoms which may be substituted with an aryl group or a heteroaryl group having 6 to 20 carbon atoms.) or X represents -NR 2 -, R 2 and Z are bonded to each other and represent a ring structure selected from the following formulas formed together with the nitrogen atom to which they are bonded. m represents an integer of 1 to 3.) 【Chemical Formula 2】 (In the formula, the wavy line represents the bonding position.)

2. The rubber compounding agent according to claim 1, wherein the component (A) is one or more selected from organosilicon compounds represented by the following formula. 【Chemical Formula 3】 (In the formula, Me represents a methyl group and Et represents an ethyl group.)

3. The rubber compounding agent according to claim 2, wherein the component (A) is one or more selected from organosilicon compounds represented by the following formula. 【Chemical Formula 4】 (In the formula, Me represents a methyl group and Et represents an ethyl group.)

4. The rubber compounding agent according to any one of claims 1 to 3, wherein the mixing ratio of the component (A) and the component (B) is (B) / (A) = 10 / 90 to 95 / 5 by mass ratio.

5. A rubber composition containing the rubber compounding agent according to any one of claims 1 to 4.

6. Furthermore, (C) a diene rubber, and (D) a filler The rubber composition according to claim 5, containing the same.

7. The rubber composition, wherein the rubber composition contains components (A) to (D), the total blending amount of components (A) and (B) is 3 to 30 parts by mass with respect to 100 parts by mass of component (D), and the blending amount of component (D) is 5 to 200 parts by mass with respect to 100 parts by mass of component (C). The rubber composition according to claim 6.

8. A tire formed by molding the rubber composition according to any one of claims 5 to 7.

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