Silane coupling agent composition and rubber composition containing same

Abstract

[Problem] To provide, inter alia, a rubber composition excelling in scorching resistance, and a silane coupling agent composition by which a crosslinked product of the rubber composition, said crosslinked product excelling in hardness and viscoelasticity properties, can be obtained. [Solution] The silane coupling agent composition of the present invention comprises: a silane compound represented by formula (1); and a protein modifying agent and / or a silanization reaction accelerator.

Description

[Technical field]

[0001] The present invention relates to a silane coupling agent composition and a rubber composition containing the same. The present invention also relates to a crosslinked product of the rubber composition and a tire using the rubber composition. [Background technology]

[0002] Conventionally, silane compounds having a reactive functional group and a hydrolyzable group have been used as components of silane coupling agents to improve the dispersibility of organic polymeric materials such as rubber and inorganic materials such as silica in rubber compositions.

[0003] Usually, such silane compounds have a substituent such as a mercapto group, a polysulfide group, an amino group, or an epoxy group as a reactive functional group that is highly reactive with organic polymer materials such as rubber, and an alkoxysilyl group as a hydrolyzable group that is highly reactive with inorganic materials such as silica. For example, Patent Document 1 discloses a rubber composition containing a polysulfide-based silane coupling agent. Patent Document 2 proposes a silane compound having an amino group as a reactive functional group and a methoxy group as a hydrolyzable group.

[0004] Furthermore, Patent Document 3 proposes a rubber composition containing an organic silane compound having a monosulfide bond in order to improve the scorch resistance of the rubber composition and the heat generation characteristics (viscoelastic characteristics) of a cross-linked product of the rubber composition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-259736 [Patent Document 2] Japanese Patent Application Publication No. 11-335381 [Patent Document 3] JP 2014-177432 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the reactive functional group of the silane compound proposed in Patent Documents 1 and 2 has high polarity, and when the organic polymeric material to be mixed is low polarity, the affinity between the silane compound and the organic polymeric material is low, and there is a tendency for poor dispersion and poor mixing to occur. Therefore, when a silane coupling agent composition containing such a silane compound is contained in a rubber composition, the hardness and viscoelasticity properties of the crosslinked product of the rubber composition obtained by molding the rubber composition tend not to be sufficiently improved. On the other hand, when a conventional silane compound having a reactive functional group with low polarity is added to increase the affinity with the organic polymeric material with low polarity, the reactivity with the organic polymeric material is low, and the performance as a silane coupling agent is insufficient.

[0007] Moreover, the silane compound described in Patent Document 3 does not have an appropriate reactivity with organic polymer materials.

[0008] The present inventors have found that impurities in natural rubber (proteins, phospholipids, etc.) inhibit the coupling reaction, which causes poor mixing and poor dispersion of organic polymeric materials containing natural rubber and inorganic materials such as silica. As a result of intensively studying means for solving such problems, the present inventors have found that by blending a silane compound and a protein modifier, which have a specific structure and function as a coupling agent themselves, with a rubber composition containing diene rubber (particularly natural rubber or synthetic isoprene rubber), the coupling reaction is promoted, and as a result, the dispersibility of inorganic materials such as silica is improved, and the viscoelastic properties of rubber products obtained from the rubber composition are improved. The present inventors have also found that by blending the above-mentioned silane compound and silanization reaction accelerator with a rubber composition containing diene rubber (particularly natural rubber or synthetic isoprene rubber), the coupling reaction is promoted, and as a result, the dispersibility of inorganic materials such as silica is improved, and the viscoelastic properties of rubber products obtained from the rubber composition are improved. The present invention is based on these findings.

[0009] Therefore, an object of the present invention is to provide a silane coupling agent composition which has a suitable reactivity with organic polymeric materials such as rubber and can provide a crosslinked product of a rubber composition excellent in hardness and viscoelasticity properties while providing a crosslinked product of a rubber composition excellent in hardness and viscoelasticity properties, and a tire using the crosslinked product and having an excellent balance between wet grip properties and low fuel consumption. [Means for solving the problem]

[0010] As a result of intensive research, the present inventors have found that by using two kinds of silane compounds as a silane coupling agent, which have an alicyclic hydrocarbon portion having an olefin structure and have an affinity and moderate reactivity with organic polymer materials, and are alicyclic and have a silyl group, the coupling reaction is promoted, and as a result, when the compounded product is a rubber composition, the dispersibility of inorganic materials such as silica is improved, and the hardness and viscoelasticity properties of the crosslinked product (rubber product) obtained from the rubber composition are improved. The present invention is based on this finding.

[0011] The present invention includes the following inventions. [1] The following formula (1): [ka] [In the formula, Each R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; Each L is independently a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur; a is an integer between 0 and 1, b is an integer between 0 and 1, each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R 4 , R 5 , R 6 and R 7 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 4 Or R 5 and R 6 Or R 7 One of them is -(CH2) f - may form a bridge structure represented by f is an integer from 1 to 5; R 8 , R 9, R 10 and R 11 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 8 Or R 9 and R 10 Or R 11 One of them is -(CH2) g - may form a bridge structure represented by g is an integer from 1 to 5; R 12 , R 13 and R 14 each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms.] and a protein denaturant and / or a silanization reaction accelerator. [2] The silane compound is represented by the following formula (2): [ka] [In the formula, Each R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; h is an integer from 1 to 10; m is an integer from 1 to 10; a is an integer between 0 and 1, b is an integer between 0 and 1, each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R 4 , R 5 , R 6 and R 7 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 4 Or R 5 and R 6 Or R 7 One of them is -(CH2) f- may form a bridge structure represented by f is an integer from 1 to 5; R 8 , R 9 , R 10 and R 11 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 8 Or R 9 and R 10 Or R 11 One of them is -(CH2) g - may form a bridge structure represented by g is an integer from 1 to 5; R 12 , R 13 and R 14 each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms.] The silane coupling agent composition according to [1], wherein the compound is represented by the formula: [3] The silane coupling agent composition according to [1] or [2], wherein the protein denaturing agent is at least one selected from the group consisting of carbamide compounds, guanidine compounds, and surfactants. [4] The silane coupling agent composition according to [1] or [2], wherein the silanization reaction accelerator is at least one selected from the group consisting of carbamide compounds and guanidine compounds. [5] The silane coupling agent composition according to [4], wherein the carbamide compound is urea. [6] The silane coupling agent composition according to any one of [1] to [5], which is used for natural rubber and / or synthetic isoprene rubber. [7] A rubber composition comprising the silane coupling agent composition according to any one of [1] to [6], a diene rubber, and silica, The rubber composition has a content of the protein denaturant of 0.01 to 10 parts by mass based on 100 parts by mass of the diene rubber. [8] The rubber composition according to [7], wherein the diene rubber comprises natural rubber and / or synthetic isoprene rubber. [9] The rubber composition according to [7] or [8], wherein the content of the silica is 5 to 100 parts by mass per 100 parts by mass of the diene rubber.

[10] The rubber composition according to any one of [7] to [9], which is used for a tire.

[11] A crosslinked product of the rubber composition according to any one of [7] to

[10] .

[12] A pneumatic tire using the crosslinked product according to

[11] in a tire tread. Effect of the Invention

[0012] According to the present invention, it is possible to provide a silane coupling agent composition that can obtain a crosslinked product of a rubber composition that has an appropriate reactivity with organic polymer materials such as rubber and is excellent in hardness and viscoelasticity. It is also possible to improve the scorch resistance of a rubber composition containing natural rubber. Furthermore, according to the present invention, it is possible to provide a crosslinked product of a rubber composition that is excellent in hardness and viscoelasticity, and a tire that uses the crosslinked product and has an excellent balance between wet grip properties and low fuel consumption. [Brief description of the drawings]

[0013] [Figure 1] 1 shows a 1H-NMR chart of the silane compound (VNB-SSi) synthesized in Preparation Example 1. [Diagram 2] 1 is a chromatogram showing that the silane compound (VNB-SSi) synthesized in Preparation Example 1 was fractionated by gas chromatography into fractions (1A) and (1B), and each fraction was collected. [Diagram 3] This shows the 1H-NMR chart of the (1A) fraction of the silane compound (VNB-SSi) synthesized in Preparation Example 1. The peaks indicated by a to g and integers 1 to 7 enclosed in circles indicate the peaks of protons bonded to each carbon atom (shown in FIG. 3) of the compound represented by formula (1A). [Figure 4]This shows a C-NMR chart of the (1A) fraction of the silane compound (VNB-SSi) synthesized in Preparation Example 1. The peaks indicated by a to g and integers 1 to 7 enclosed in circles indicate the peaks of each carbon atom (shown in FIG. 4) of the compound represented by formula (1A). [Diagram 5] This shows the 1H-NMR chart of the (1B) fraction of the silane compound (VNB-SSi) synthesized in Preparation Example 1. The peaks indicated by A to G and 1 to 7 surrounded by circles indicate the peaks of protons bonded to each carbon atom (shown in FIG. 5) of the compound represented by formula (1B). [Figure 6] This shows the C-NMR chart of the (1B) fraction of the silane compound (VNB-SSi) synthesized in Preparation Example 1. The peaks A to G and 1 to 7 surrounded by circles indicate the peaks of protons bonded to each carbon atom (shown in FIG. 6) of the compound represented by formula (1B). [Figure 7] 1 shows a 1H-NMR chart of the silane compound (VNB-2SSi) synthesized in Preparation Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [Definition] In this specification, the units "parts", "%" and the like indicating the composition are based on mass unless otherwise specified.

[0015] [Silane coupling agent composition] The silane coupling agent composition of the present invention is characterized by containing the following silane compound, and a protein denaturant and / or a silanization reaction accelerator. By adding the silane coupling agent composition of the present invention to diene rubber, particularly natural rubber, it is possible to obtain a rubber composition having moderate reactivity and excellent scorch resistance, as well as a crosslinked product of the rubber composition having excellent hardness and viscoelasticity properties.

[0016] The content of the silane compound in the silane coupling agent composition is preferably 20 to 99% by mass, more preferably 50 to 95% by mass, and even more preferably 60 to 90% by mass, based on the total mass of the silane coupling agent composition. The total content of the protein denaturant and the silanization reaction accelerator in the silane coupling agent composition is preferably 0.1 to 50% by mass, more preferably 1 to 45% by mass, and even more preferably 5 to 40% by mass, based on the total mass of the silane coupling agent composition. If the content of the silane compound, the protein denaturant, and the silanization reaction accelerator in the silane coupling agent composition is within the above numerical range, it is easy to obtain a rubber composition having excellent scorch resistance while having moderate reactivity with organic polymer materials such as rubber, and a crosslinked product of the rubber composition having excellent hardness and viscoelasticity properties.

[0017] The silane coupling agent composition may further contain carbon black. As the carbon black, the carbon black described in the inorganic material described below can be used. Each component of the silane coupling agent composition will be described in detail below.

[0018] (Silane compounds) The silane compound contained in the silane coupling agent composition of the present invention is represented by the following formula (1): [ka] [In the formula, Each R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; Each L is independently a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur; a is an integer between 0 and 1, b is an integer between 0 and 1, each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R 4 , R 5 , R 6 and R 7 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 4 Or R 5 and R 6 Or R 7 One of them is -(CH2) f - may form a bridge structure represented by f is an integer from 1 to 5; R 8 , R 9 , R 10 and R 11 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 8 Or R 9 and R 10 Or R 11 One of them is -(CH2) g - may form a bridge structure represented by g is an integer from 1 to 5; R 12 , R 13 and R 14 each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms.] It is a compound represented by the formula:

[0019] In the above formula (1), a is an integer of 0 or 1, and is preferably 1. Furthermore, b is an integer of 0 or 1, and is preferably 1. Each c is independently an integer of 0 or 1, and preferably 1. Each d is independently an integer of 0 or 1, and preferably 1. Furthermore, e is an integer of 0 to 5, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and further preferably an integer of 0 or 1. Also, R 4 , R 5 , R6 and R 7 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 4 Or R 5 and R 6 Or R 7 One of them is -(CH2) f A crosslinked structure represented by the formula - may be formed. Furthermore, f is an integer of 1 to 5, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, and further preferably 1. Also, R 8 , R 9 , R 10 and R 11 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 8 Or R 9 and R 10 Or R 11 One of them is -(CH2) g A crosslinked structure represented by the formula - may be formed. Furthermore, g is an integer of 1 to 5, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, and further preferably 1. Also, R 12 , R 13 and R 14 each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, and is preferably a hydrogen atom.

[0020] In addition, in the above formula (1), R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom. Examples of the hydrocarbon group include an alkyl group, an aralkyl group, and an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a tert-butyl group, a 2-ethylhexyl group, a cyclopentyl group, and a cyclohexyl group. The alkyl group preferably has 1 to 60 carbon atoms, more preferably 1 to 30 carbon atoms, and among these, a methyl group or an ethyl group is preferable. Examples of the aralkyl group include a benzyl group, a phenethyl group, a naphthylmethyl group, a biphenylmethyl group, etc. The aralkyl group preferably has 7 to 60 carbon atoms, more preferably 7 to 20 carbon atoms, and further preferably 7 to 14 carbon atoms. Examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, a xylyl group, etc. The aryl group preferably has 6 to 60 carbon atoms, more preferably 6 to 24 carbon atoms, and further preferably 6 to 12 carbon atoms. The hydrocarbon group containing an oxygen atom or a nitrogen atom is a group having a structure in which a carbon atom in a hydrocarbon group is replaced with an oxygen atom or a nitrogen atom.

[0021] In a further preferred embodiment of the present invention, the above R 1 , R 2 and R 3 The hydrocarbon group which may contain an oxygen atom or a nitrogen atom in is an alkoxy group, an amino group substituted with one or more alkyl groups, or an alkyl group. More preferably, it is an alkoxy group having 1 to 30 carbon atoms, even more preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an amino group substituted with one or more alkyl groups having 1 to 30 carbon atoms, even more preferably an amino group substituted with one or more alkyl groups having 1 to 20 carbon atoms, or even more preferably an alkyl group having 1 to 30 carbon atoms, even more preferably an alkyl group having 1 to 20 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and an isobutoxy group, and among these, a methoxy group or an ethoxy group is preferred. Examples of the amino group substituted with one or more alkyl groups include an N-methylamino group, an N,N-dimethylamino group, an N-ethylamino group, an N,N-diethylamino group, and an N-isopropylamino group, and among these, an N-methylamino group or an N-ethylamino group is preferred. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, a hexyl group, and a cyclohexyl group. Of these, a methyl group and an ethyl group are preferred.

[0022] In the above formula (1), L is a hydrocarbon group that may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, preferably a hydrocarbon group having 1 to 30 carbon atoms that may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, more preferably a hydrocarbon group having 1 to 20 carbon atoms that may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, and even more preferably a hydrocarbon group having 1 to 10 carbon atoms that may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur. Among them, L is particularly preferably a hydrocarbon group containing sulfur. The length of the straight chain portion connecting the silyl group and the alicyclic hydrocarbon portion in such a hydrocarbon group is preferably 3 to 8, more preferably 4 to 7, and even more preferably 4 to 6, as the total number of carbon, nitrogen, oxygen, or sulfur atoms.

[0023] The silane compound in the silane coupling agent composition of the present invention is preferably a sulfur-containing silane compound.

[0024] The silane compound contained in the silane coupling agent composition of the present invention is preferably a silane compound represented by the formula (2): [ka] [In the formula, Each R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; h is an integer from 1 to 10; m is an integer from 1 to 10; a is an integer between 0 and 1, b is an integer between 0 and 1, each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R4 , R 5 , R 6 and R 7 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 4 Or R 5 and R 6 Or R 7 One of them is -(CH2) f - may form a bridge structure represented by f is an integer from 1 to 5; R 8 , R 9 , R 10 and R 11 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 8 Or R 9 and R 10 Or R 11 One of them is -(CH2) g - may form a bridge structure represented by g is an integer from 1 to 5; R 12 , R 13 and R 14 each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms.] It is a compound represented by the formula:

[0025] In the compound represented by the above formula (2), h is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 2 to 7, further preferably an integer of 3 to 6, even more preferably an integer of 3 to 5, and particularly preferably an integer of 3. m is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 6, further preferably an integer of 1 to 4, and even more preferably an integer of 1 to 3. In addition, a to g and R 1 ~R 14 is as explained in relation to the above formula (1).

[0026] The silane compound contained in the silane coupling agent composition of the present invention is more preferably a silane compound represented by formula (3): [ka] [In the formula, each R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; or Formula (4): [ka] [In the formula, each R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom. It is a compound represented by the formula:

[0027] In the compounds represented by the above formula (3) and formula (4), each R 1 , R 2 and R 3 is as explained in relation to the above formula (1).

[0028] Another preferred embodiment of the silane compound in the silane coupling agent composition of the present invention is a compound represented by the following formula: 1 ~R 3 is as explained in relation to the above formula (1). [ka] TIFF0007631342000008.tif127150

[0029] As a further preferred embodiment of the silane compound contained in the silane coupling agent composition of the present invention, in each of the above formulas, R 1 R 2 R 3 The Si group is represented by the following formula (5): [ka] [In the formula, R 19each independently represents an amino group substituted with an alkoxy group or one or more alkyl groups, R 20 are each independently a hydrogen atom or an alkyl group, L 1 each independently represents a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur; Each j is independently an integer of 0 or 1; k is an integer from 1 to 3; The asterisk (*) indicates a bond site with a moiety other than the silyl group of the silane compound. Examples of the silane compound include a silane compound having the following chemical structure:

[0030] In the above formula (5), R 19 are each independently an alkoxy group or an amino group substituted with one or more alkyl groups. In one preferred embodiment, R 19 are each independently a hydrolyzable group, and are an alkoxy group, more preferably an alkoxy group having 1 to 30 carbon atoms, even more preferably an alkoxy group having 1 to 20 carbon atoms, or an amino group substituted with one or more alkyl groups, more preferably an amino group substituted with one or more alkyl groups having 1 to 30 carbon atoms, even more preferably an amino group substituted with one or more alkyl groups having 1 to 20 carbon atoms. Specifically, the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and an isobutoxy group, and among these, a methoxy group or an ethoxy group is preferred. In addition, the amino group substituted with one or more alkyl groups includes an N-methylamino group, an N,N-dimethylamino group, an N-ethylamino group, an N,N-diethylamino group, and an N-isopropylamino group, and among these, an N-methylamino group or an N-ethylamino group is preferred. The alkoxy group and the amino group may be bonded to silicon (Si) via a linking group consisting of a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur. Also, R 20are each independently a hydrogen atom or an alkyl group, more preferably an alkyl group having 1 to 30 carbon atoms, and even more preferably an alkyl group having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, a hexyl group, and a cyclohexyl group, and among these, a methyl group and an ethyl group are preferred.

[0031] In the above formula (5), L 1 are each independently a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, preferably a hydrocarbon group having 1 to 30 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, more preferably a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, and even more preferably a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur.

[0032] In the above formula (5), k is an integer of 1 to 3, preferably an integer of 2 to 3, and more preferably 3. Each j is independently an integer of 0 or 1, and is preferably 0.

[0033] The silane compound contained in the silane coupling agent composition of the present invention is R 1 R 2 R 3 More preferred are silane compounds in which the Si group is a triethoxysilyl group or a trimethoxysilyl group, and R 1 R 2 R 3 Even more preferred are silane compounds in which the Si group is a triethoxysilyl group.

[0034] Particularly preferred embodiments of the silane compound contained in the silane coupling agent composition of the present invention include compounds represented by the following formula. [ka] TIFF0007631342000011.tif152153

[0035] The silane compounds of the present invention are preferably any of the stereoisomers or any mixture of the stereoisomers.

[0036] (Method of Producing Silane Compound) An embodiment of a method for producing the silane compound represented by formula (1) contained in the silane coupling agent composition of the present invention will be described below, but the method is not limited to the following. For example, the silane compound represented by formula (1) can be produced by a method represented by formula (6): [ka] [In the formula, a is an integer between 0 and 1, b is an integer between 0 and 1, each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R 4 , R 5 , R 6 and R 7 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 4 Or R 5 and R 6 Or R 7 One of them is -(CH2) f - may form a bridge structure represented by f is an integer from 1 to 5; R 8 , R 9 , R 10 and R 11 represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R 8 Or R 9 and R 10 Or R 11 One of them is -(CH2)g - may form a bridge structure represented by g is an integer from 1 to 5; R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, provided that R 12 and R 15 are bonded together to form a double bond, or R 16 and R 17 are bonded to each other to form a double bond, and R 13 and R 18 may be bonded to each other to form a 4- to 9-membered alicyclic hydrocarbon.] and a compound represented by formula (7): [ka] [In the formula, R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; Y is a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur. The compound represented by the formula (I) can be produced by reacting a compound represented by the formula (I).

[0037] In the above formula (6) and formula (7), R 1 ~R 14 And preferred embodiments of a to g are as explained in formula (1) above.

[0038] In the above formula (7), Y is a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur, preferably a hydrocarbon group having 1 to 30 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur, more preferably a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur, and even more preferably a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur. Among them, Y is particularly preferably a hydrocarbon group containing sulfur. The length of the straight chain portion connecting the bonding site of the silyl group and the alicyclic hydrocarbon moiety in such a hydrocarbon group is preferably 3 to 8, more preferably 4 to 7, and even more preferably 4 to 6, as the total number of carbon, nitrogen, oxygen or sulfur atoms.

[0039] Here, in the production of the silane compound represented by the above formula (1), the compound represented by formula (6) and the compound represented by formula (7) can be subjected to an addition reaction or a condensation reaction to synthesize the compound. The addition reaction in this case can be a radical addition reaction, a conjugate addition reaction, a nucleophilic addition reaction, an electrophilic addition reaction, or the like, and for example, a reaction similar to a pericyclic reaction, a hydrosilylation reaction, a hydroamination reaction, or the like can be used. The condensation reaction can be, for example, an esterification reaction, an amidation reaction, a thioesterification reaction, a thioamidation reaction, a Friedel-Crafts reaction, or the like.

[0040] The compound represented by the above formula (6) can be synthesized by Diels-Alder reaction between the same or different conjugated diene compounds, or Diels-Alder reaction between a conjugated diene compound and an alkene compound, based on knowledge already known to those skilled in the art. The compound represented by the formula (6) can also be prepared by heat-denaturing, if necessary, the compound synthesized by the Diels-Alder reaction, and / or purifying, if necessary.

[0041] The silane compound represented by formula (2) contained in the silane coupling agent composition of the present invention is a compound represented by formula (6) and a compound represented by formula (8): [ka] [In the formula, R 1 , R 2 and R 3 each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; and h is an integer from 1 to 10. The compound represented by the formula (I) can be produced by reacting a compound represented by the formula (I).

[0042] In the above formula (8), R 1 ~R 3 Preferred embodiments of and h are as explained in formula (2) above.

[0043] Here, the compound represented by the formula (2) is considered to be synthesized by mixing the compound represented by the formula (6) and the compound represented by the formula (8) and heating the mixture to cause a reaction between the mercapto group in the compound represented by the formula (8) and the two carbon-carbon unsaturated bond portions in the compound represented by the formula (6). The compound represented by the formula (8) is preferably mixed in an amount of 0.1 to 4 moles, more preferably 0.3 to 3 moles, per mole of the compound represented by the formula (6). The heating temperature is preferably 40 to 300°C, more preferably 50 to 200°C.

[0044] Examples of the compound represented by the formula (8) include alkoxysilane compounds having a mercapto group. Examples of the alkoxysilane compounds having a mercapto group include mercaptotrimethoxysilane, mercaptotriethoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, mercaptomethyltripropoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 4-mercaptobutyltrimethoxysilane, 3-mercaptopropyltriethoxy ... Examples of mercaptoethyltriethoxysilane include 2-mercaptoethyltripropoxysilane, 3-mercaptopropyltripropoxysilane, 4-mercaptobutyltripropoxysilane, 2-mercaptoethylmethyldimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 4-mercaptobutylmethyldimethoxysilane, 2-mercaptoethylmethyldiethoxysilane, 3-mercaptopropylmethyldiethoxysilane, and 4-mercaptobutylmethyldiethoxysilane.

[0045] The compound represented by the above formula (2) can also be synthesized by mixing the compound represented by the above formula (8) and the compound represented by the formula (9) described later and heating the mixture. It is believed that the polysulfide bond in the compound represented by the formula (9) described later is cleaved and reacts with two carbon-carbon unsaturated bond portions in the compound represented by the above formula (6), thereby synthesizing the compound. The compound represented by the formula (9) described later is preferably mixed in an amount of 0.1 to 4 moles, more preferably 0.3 to 3 moles, per mole of the compound represented by the above formula (6). The heating temperature is preferably 40 to 300°C, more preferably 50 to 200°C.

[0046] If necessary, a radical initiator can be used in combination. Examples of radical initiators include azo compounds such as azobisisobutyronitrile (AIBN) and 1,1'-azobis(cyclohexanecarbonitrile) (ABCN), di-tert-butyl peroxide (t-BuOOBu-t), tert-butyl hydroperoxide (t-BuOOH), benzoyl peroxide (BPO, PhC(=O)OOC(=O)pH), methyl ethyl ketone peroxide, dicumyl peroxide (DCP), and other peroxides, dihalogen compounds such as chlorine molecules, and redox initiators that are combinations of oxidizing agents and reducing agents, such as hydrogen peroxide and iron (II) salts, persulfates and sodium hydrogen sulfite, as reagents that can generate radicals at low temperatures, and triethylborane (Et3B) and diethylzinc (Et2Zn) can also be used.

[0047] Among the compounds represented by formula (9) described later, commercially available bis[3-(triethoxysilyl)propyl]tetrasulfide may be used, for example, Si-69 manufactured by Evonik. Also, commercially available bis[3-(triethoxysilyl)propyl]disulfide may be used, for example, Si-75 manufactured by Evonik.

[0048] (Other silane compounds) The silane coupling agent composition of the present invention may further contain other silane compounds (sometimes referred to as "other silane compounds" in this specification) other than the silane compound represented by the above formula (1). When a rubber composition containing the silane coupling agent composition of the present invention is vulcanized, the other silane compounds are also incorporated in the vulcanization reaction, so that the silane compound represented by the above formula (1) that functions as a silane coupling agent reacts with the other silane compounds. It is believed that this reaction produces a synergistic effect of increasing coupling efficiency. In the rubber composition of the present invention, the other silane compounds are preferably sulfur-containing silane compounds other than the silane compound represented by the above formula (1).

[0049] Other silane compounds include, for example, compounds of the formula (9): [ka] [In the formula, t and v each independently represent an integer of 0 to 10; u is an integer from 2 to 10; q and r each independently represent an integer of 1 to 3; w and z are each independently an integer of 0 or 1; L 2 and L 3 each independently represents a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur; R 21 and R 23 each independently represents an amino group substituted with an alkoxy group or one or more alkyl groups, R 22 and R 24 are each independently a hydrogen atom or an alkyl group. It is possible to use a compound represented by the following formula:

[0050] In the above formula (9), t and v each independently represent an integer of 0 to 10, preferably an integer of 0 to 5, more preferably an integer of 1 to 3, and even more preferably 2. Furthermore, u is an integer of 2-10, and more preferably an integer of 2-8. Furthermore, q and r each independently represent an integer of 1 to 3, preferably an integer of 2 to 3, and more preferably 3. Furthermore, w and z each independently represent an integer of 0 or 1, and are preferably 0. Also, L 2 and L 3are each independently a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, preferably a hydrocarbon group having 1 to 30 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, more preferably a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur, and even more preferably a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur. Also, R 21 and R 23 are each independently a hydrolyzable group, and are an alkoxy group, more preferably an alkoxy group having 1 to 30 carbon atoms, even more preferably an alkoxy group having 1 to 20 carbon atoms, or an amino group substituted with one or more alkyl groups, more preferably an amino group substituted with one or more alkyl groups having 1 to 30 carbon atoms, and more preferably an amino group substituted with one or more alkyl groups having 1 to 20 carbon atoms. Specifically, the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and an isobutoxy group, and among these, a methoxy group or an ethoxy group is preferred. In addition, the amino group substituted with one or more alkyl groups includes an N-methylamino group, an N,N-dimethylamino group, an N-ethylamino group, an N,N-diethylamino group, and an N-isopropylamino group, and among these, an N-methylamino group or an N-ethylamino group is preferred. The alkoxy group and the amino group may be bonded to silicon (Si) via a linking group consisting of a hydrocarbon group which may contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur. Also, R 22 and R 24are each independently a hydrogen atom or an alkyl group, more preferably an alkyl group having 1 to 30 carbon atoms, and even more preferably an alkyl group having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, a hexyl group, and a cyclohexyl group, and among these, a methyl group and an ethyl group are preferred.

[0051] As the other silane compound, in addition to the compound represented by the above formula (9), the compound represented by the above formula (8), particularly a silane compound having the following structure, can be used. [ka]

[0052] The content of the other silane compounds in the silane coupling agent composition of the present invention is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, in terms of mass ratio relative to the total content of the silane compound represented by the above formula (1) and the other silane compounds.

[0053] (Protein Denaturant) In the silane coupling agent composition of the present invention, a protein denaturant known to those skilled in the art can be used as a protein denaturant. The protein denaturant may be any one that can reduce the stability of the higher-order structure of protein in diene rubber, particularly natural rubber. Representative protein denaturants include carbamide compounds such as urea derivatives and thiourea; guanidine compounds such as guanidine hydrochloride, guanidinium thiocyanate, guanidine, and diphenylguanidine; surfactants such as sodium dodecyl sulfate; glutaraldehyde, dimethyl suberimidate dihydrochloride, β-mercaptoethanol, and dithiothreitol. Any one of these protein denaturants may be used, or two or more may be used in combination. Among these, it is preferable to use carbamide compounds, guanidine compounds, surfactants, glutaraldehyde, and dimethyl suberimidate dihydrochloride, and it is more preferable to use urea derivatives, guanidine hydrochloride, diphenylguanidine, sodium dodecyl sulfate, glutaraldehyde, and dimethyl suberimidate dihydrochloride. Examples of urea derivatives include urea, methylurea, ethylurea, propylurea, butylurea, pentylurea, hexylurea, cyclohexylurea, N,N'-dimethylurea, N,N'-diethylurea, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, diethylurea, dipropylurea, dibutylurea, dipentylurea, dihexylurea, and salts thereof. Among these, urea is excellent. By using a protein denaturant, the scorch resistance of the rubber composition can be improved. Furthermore, the silane coupling agent composition of the present invention preferably contains both a carbamide compound and a guanidine compound.

[0054] (Silanization reaction accelerator) The silane coupling agent composition of the present invention can use a silanization reaction accelerator. The silanization reaction accelerator may be any one that accelerates the silanization reaction between silica and a silane coupling agent. Examples of the silanization reaction accelerator include carbamide compounds such as urea derivatives and thiourea; guanidine compounds such as guanidine hydrochloride, guanidinium thiocyanate, guanidine, and diphenylguanidine. These silanization reaction accelerators may be used alone or in combination of two or more. Examples of urea derivatives include urea, methylurea, ethylurea, propylurea, butylurea, pentylurea, hexylurea, cyclohexylurea, N,N'-dimethylurea, N,N'-diethylurea, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, diethylurea, dipropylurea, dibutylurea, dipentylurea, dihexylurea, and salts thereof. Among these, urea is preferable.

[0055] In the first stage of the silanization reaction between silica and a silane coupling agent, there are two reaction processes: a direct reaction (de-alcoholization condensation) between the alkoxy group of the silane coupling agent and the silanol group on the silica surface, and then the alkoxy group of the silane coupling agent is hydrolyzed and then dehydrated and condensed with the silanol group on the silica surface. In the second stage of the silanization reaction, a condensation reaction occurs between adjacent silane coupling agents chemically bonded to the silica surface. The hydrolysis of the silane coupling agent in the first stage reaction is the reaction rate limiting, but the presence of a silanization reaction accelerator such as a urea derivative increases the rate of the hydrolysis reaction, and it is thought that the silanization reaction is accelerated.

[0056] In the present invention, carbamide compounds and guanidine compounds may function as both a protein denaturant and a silanization reaction accelerator. For example, when a silane coupling agent composition containing urea is added to a rubber composition, the urea may exhibit both a protein denaturing effect on natural rubber and the like, and an accelerating effect on the silanization reaction of silica and the silane coupling agent. In this case, when the content of urea is X% by mass with respect to the total mass of the silane coupling agent composition, the above-mentioned "total content of protein denaturant and silanization reaction accelerator" is X% by mass with respect to the total mass of the silane coupling agent composition (i.e., the content of urea is not calculated in duplicate as both the protein denaturant and the silanization reaction accelerator).

[0057] [Rubber composition] The rubber composition of the present invention is characterized by including the silane coupling agent composition of the present invention, a diene rubber, and silica. The rubber composition of the present invention has excellent scorch resistance, and therefore has good processability. Furthermore, by using the rubber composition of the present invention, a crosslinked product having excellent hardness and viscoelasticity properties can be obtained. Such a rubber composition can be suitably used for tires. Each component of the rubber composition will be described in detail below. The silane coupling agent composition is as described above in detail.

[0058] The content of the silane compound represented by the above formula (1) in the rubber composition is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and further preferably 1.0 to 15 parts by mass, based on 100 parts by mass of silica. If the content of the silane compound is within the above numerical range, the hardness and viscoelasticity properties of the crosslinked product of the rubber composition can be improved, and a tire having excellent steering stability and an excellent balance between wet grip properties and low fuel consumption can be obtained.

[0059] The content of the other silane compound in the rubber composition is preferably 0.01 to 20 parts by mass, and more preferably 0.05 to 10 parts by mass, based on 100 parts by mass of silica.

[0060] The content of the protein modifier in the rubber composition varies depending on the type of protein modifier, but may be any amount as long as it reduces the stability of the higher-order structure of the protein. The content of the protein modifier in the rubber composition is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.2 to 3.0 parts by mass, relative to 100 parts by mass of the diene rubber. When two or more types of protein modifiers are included, the total content is preferably within the above numerical range. If the content of the protein modifier is within the above numerical range, the scorch resistance of the rubber composition can be improved. In addition, for example, when a carbamide compound such as urea is used as the protein modifier, it may be preferably contained in an amount of 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the diene rubber. Also, for example, when a guanidine compound such as guanidine hydrochloride is used as a protein denaturant, it may be contained in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of diene rubber. In particular, the effect becomes more pronounced when a guanidine compound is used in combination with a carbamide compound, and in this case, the ratio of the content of the guanidine compound to the content of the carbamide compound (guanidine compound / carbamide compound) is preferably 0.01 to 3, more preferably 0.05 to 2, and even more preferably 0.1 to 1.

[0061] The content of the silanization reaction accelerator in the rubber composition varies depending on the type of the silanization reaction accelerator, but may be any amount as long as it accelerates the silanization reaction. The content of the silanization reaction accelerator in the rubber composition is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.2 to 3.0 parts by mass, relative to 100 parts by mass of the diene rubber. When two or more types of silanization reaction accelerators are included, the total content is preferably within the above numerical range. If the content of the silanization reaction accelerator is within the above numerical range, the scorch resistance of the rubber composition can be improved. In addition, for example, when a carbamide compound such as urea is used as the silanization reaction accelerator, it is preferable to include 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the diene rubber. For example, when a guanidine compound such as guanidine hydrochloride is used as the silanization reaction accelerator, it is preferable to add it in an amount of 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the diene rubber. In particular, the effect becomes more pronounced when a guanidine compound is used in combination with a carbamide compound, and in this case, the ratio of the content of the guanidine compound to the content of the carbamide compound (guanidine compound / carbamide compound) is preferably 0.01 to 3, more preferably 0.05 to 2, and even more preferably 0.1 to 1.

[0062] (Diene rubber) The diene rubber contained in the rubber composition of the present invention includes isoprene rubber and other diene rubber. Examples of isoprene rubber include natural rubber (NR), deproteinized natural rubber, and synthetic isoprene rubber. Here, deproteinized natural rubber is natural rubber that has been subjected to a deproteinization process, and although the protein content is lower than that of normal natural rubber, it is not completely removed. Natural rubber or deproteinized natural rubber contains impurities derived from natural rubber (proteins, phospholipids, etc.), which inhibit the coupling reaction of the silane coupling agent, causing a problem that inorganic materials such as silica blended are not sufficiently dispersed in the rubber composition. In the present invention, in order to solve such a problem, when natural rubber and / or synthetic isoprene rubber is used as the diene rubber, a protein denaturant and / or a silanization reaction accelerator is blended into the silane coupling agent composition. Examples of natural rubber include natural rubber latex, technically graded rubber (TSR), smoked sheet (RSS), gutta percha, eucommia-derived natural rubber, guayule-derived natural rubber, Russian dandelion-derived natural rubber, and plant-based fermented rubber. Modified natural rubbers obtained by modifying these natural rubbers, such as epoxidized natural rubber, methacrylic acid-modified natural rubber, styrene-modified natural rubber, sulfonic acid-modified natural rubber, and zinc sulfonate-modified natural rubber, are also included in natural rubber. There is no particular restriction on the cis / trans / vinyl ratio of the double bonds in natural rubber, and any ratio can be suitably used. Examples of synthetic isoprene rubber include a copolymer of cis-1,4 isoprene, trans-1,4 isoprene, and 3,4 isoprene (so-called isoprene rubber (IR)). Examples of rubbers that partially have the structure of synthetic isoprene rubber include isoprene-butadiene rubber and halogenated isoprene rubber. In the present invention, it is preferable to use isoprene rubber (IR) as the diene rubber, and more preferable to use synthetic isoprene rubber containing 75% or more of cis-1,4 isoprene structure. The number average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, but the number average molecular weight is preferably 500 to 3,000,000 and the molecular weight distribution is preferably 1.5 to 15.

[0063] Other diene rubbers include butadiene rubber, styrene-butadiene rubber, styrene-isoprene-butadiene rubber, styrene-isoprene rubber, partially hydrogenated styrene-butadiene rubber, styrene-α-methylstyrene-butadiene rubber, ethylene-propylene-diene rubber, and the like.

[0064] The method for producing the diene rubber is not particularly limited, and examples thereof include emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization, etc. The glass transition point is also not particularly limited.

[0065] The content of the diene rubber is preferably 20 to 80 mass %, more preferably 25 to 75 mass %, and further preferably 30 to 70 mass %, based on the total solid mass of the rubber composition.

[0066] (Inorganic materials) Examples of inorganic materials contained in the rubber composition of the present invention include silica, carbon black, calcium carbonate, titanium oxide, clay, and talc, and these can be used alone or in combination. Among these, at least silica is used in the present invention because it can further improve mechanical properties and heat resistance. The amount of inorganic material added is preferably 0.1 to 500 parts by mass, more preferably 1 to 300 parts by mass, based on 100 parts by mass of diene rubber.

[0067] The silica is not particularly limited, but examples thereof include dry process silica, wet process silica, colloidal silica, and precipitated silica. Among these, wet process silica containing hydrated silicic acid as a main component is preferred. These silicas can be used alone or in combination of two or more. The specific surface area of ​​these silicas is not particularly limited, but is usually 10 to 400 m in terms of nitrogen adsorption specific surface area (BET method). 2 / g, preferably 20 to 300m 2 / g, more preferably 120 to 190m 2When the specific surface area is in the range of / g, the reinforcement, abrasion resistance, heat generation, etc. are sufficiently improved, and it is preferable. Here, the nitrogen adsorption specific surface area is a value measured by the BET method in accordance with ASTM D3037-81. The amount of silica added is preferably 1 to 300 parts by mass, more preferably 5 to 200 parts by mass, and further preferably 10 to 150 parts by mass, based on 100 parts by mass of the diene rubber.

[0068] Carbon black is appropriately selected and used depending on the application. Generally, carbon black is classified into hard carbon and soft carbon based on the particle size. Soft carbon has low reinforcing properties for rubber, and hard carbon has high reinforcing properties for rubber. In the rubber composition of the present invention, it is preferable to use hard carbon, which has particularly high reinforcing properties. The amount of carbon black added is preferably 1 to 300 parts by mass, more preferably 5 to 200 parts by mass, and even more preferably 10 to 150 parts by mass, based on 100 parts by mass of diene rubber. Carbon black may be added to the rubber composition or the silane coupling agent composition.

[0069] (Other processing aids) The rubber composition of the present invention may contain other processing aids, such as a vulcanizing agent such as sulfur, a vulcanization accelerator, a vulcanization acceleration assistant, an antioxidant, a colorant, a softener, various oils, an antioxidant, a filler, and a plasticizer, within a range that does not deviate from the spirit of the present invention.

[0070] Examples of the vulcanizing agent include sulfur-based vulcanizing agents such as powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, and alkylphenol disulfide, as well as zinc oxide, magnesium oxide, litharge, p-quinone dioxam, p-dibenzoylquinone dioxime, tetrachloro-p-benzoquinone, poly-p-dinitrobenzene, methylenedianiline, phenol resin, brominated alkylphenol resin, and chlorinated alkylphenol resin. The amount of the vulcanizing agent added is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the diene rubber.

[0071] Examples of the vulcanization accelerator include thiuram-based accelerators such as tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), and tetramethylthiuram monosulfide (TMTM), aldehyde-ammonia-based accelerators such as hexamethylenetetramine, guanidine-based accelerators such as diphenylguanidine, thiazole-based accelerators such as 2-mercaptobenzothiazole (MBT) and dibenzothiazyl disulfide (DM), sulfenamide-based accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide (CBS) and Nt-butyl-2-benzothiazylsulfenamide (BBS), and dithiocarbamate-based accelerators such as zinc dimethyldithiocarbamate (ZnPDC). The amount of the vulcanization accelerator added is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the diene rubber.

[0072] Examples of the vulcanization accelerator include fatty acids such as acetyl acid, propionic acid, butanoic acid, stearic acid, acrylic acid, and maleic acid, zinc fatty acids such as zinc acetylate, zinc propionate, zinc butanoate, zinc stearate, zinc acrylate, and zinc maleate, and zinc oxide. The amount of the vulcanization accelerator added is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the diene rubber.

[0073] Examples of the antioxidant include hindered phenol compounds, aliphatic and aromatic hindered amine compounds, etc. The amount of the antioxidant added is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the diene rubber.

[0074] Examples of the antioxidant include butylhydroxytoluene (BHT), butylhydroxyanisole (BHA), etc. The amount of the antioxidant added is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the diene rubber.

[0075] Examples of the colorant include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, azo pigment, copper phthalocyanine pigment, etc. The amount of the colorant added is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the diene rubber.

[0076] In the present invention, the other processing aids can be kneaded with a known rubber kneading machine, such as a roll, a Banbury mixer, a kneader, etc., and vulcanized under any conditions to be used as a rubber composition. The amounts of these other processing aids added can be conventional general amounts added without departing from the spirit of the present invention.

[0077] [Method of manufacturing rubber composition] The method for producing the rubber composition of the present invention comprises a step of kneading the silane coupling agent, the diene rubber, and the inorganic material. The method for producing the rubber composition of the present invention preferably comprises a step of kneading the silane coupling agent, the diene rubber, the inorganic material, and the vulcanization accelerator.

[0078] The method for producing the rubber composition of the present invention may preferably further include a step of kneading the vulcanizing agent, and more preferably may further include a step of kneading the vulcanizing agent and the vulcanization accelerator.

[0079] In each of the above steps, the rubber composition may be appropriately blended with the other processing aids described above without departing from the spirit of the present invention.

[0080] For producing the rubber composition, a conventionally known kneading device can be used, and the kneading temperature, time, compounding order, etc. can be appropriately selected.

[0081] [Cross-linked product of rubber composition] Using the rubber composition of the present invention, a crosslinked product of the rubber composition can be produced according to a conventionally known method and common technical knowledge widely known to those skilled in the art. For example, the rubber composition is extruded, then molded using a molding machine, and then heated and pressed using a vulcanizer to form crosslinks, thereby producing a crosslinked product.

[0082] [tire] The tire of the present invention contains a crosslinked product of the rubber composition of the present invention. The tire of the present invention can be manufactured by using the above rubber composition according to a conventionally known method and common technical knowledge widely known to those skilled in the art. For example, the above rubber composition is extruded, then molded using a tire building machine, and then crosslinked by heating and pressurizing using a vulcanizer, thereby manufacturing a tire. By manufacturing a tire using the rubber composition of the present invention, it is possible to improve the wet grip property and fuel economy in tire performance in a well-balanced manner.

[0083] The uses of the tires are not particularly limited, and examples thereof include passenger car tires, heavy load tires, motorcycle (two-wheeled motor vehicles) tires, and studless tires.

[0084] The shape, structure, size and material of the tire are not particularly limited and can be appropriately selected depending on the purpose. The tire can be applied to each part of the tire, and the part to which the tire is applied is not particularly limited and can be appropriately selected depending on the purpose, such as the tread, carcass, sidewall, inner liner, undertread, belt part, etc. In the present invention, a pneumatic tire using the rubber composition in the tire tread is preferred. EXAMPLES

[0085] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0086] [Preparation Example 1: Synthesis of silane compound (VNB-SSi)] A 100mL three-neck flask was fitted with a ball stopper, a three-way cock connected to a vacuum / dry nitrogen line, and a septum, then a stirrer bar was placed in the flask, and the system was degassed and replaced with nitrogen 10 times while heating with a dryer, creating a nitrogen atmosphere at normal pressure. 27.5g (0.225mol) of 2-vinylnorbornene (VNB) was injected into the flask using a syringe, and 0.074g (0.45mmol) of azobisisobutyronitrile was added under a nitrogen atmosphere, after which nitrogen bubbling was performed for 20 minutes. Next, 10.7g (0.045mol) of mercaptopropyltriethoxysilane was aspirated using a gas-tight syringe and attached to a metering pump, which was set to drip the entire amount in 3 hours. Finally, the connection was sealed with silicon grease, the needle tip of a gas-tight syringe was introduced into the flask through the septum, the flask was immersed in an oil bath, and the bath temperature was gradually increased. When the internal temperature reached 50°C, the metering pump was operated and mercaptopropyltriethoxysilane was dripped in to cause a reaction. Two hours after the entire amount had been dripped in, the oil bath was removed from the flask and the flask was allowed to stand at room temperature. Next, the excess VNB was distilled off under reduced pressure, and 37.4 g of the desired colorless, clear liquid was obtained. 1 The results of H-NMR are shown in Figure 1. 1 H-NMR measurements and 13 C-NMR measurement confirmed that the silane introduction rate was 100% and that the double bond in the norbornene ring had disappeared. [ka]

[0087] [Detection of stereoisomers of silane compound (VNB-SSi)] The silane compound obtained above was fractionated by gas chromatography into a fraction containing a large amount of the compound represented by the above formula (1A) ("fraction (1A)") and a fraction containing a large amount of the compound represented by the above formula (1B) ("fraction (1B)"), and the fraction was collected (Figure 2). 1 The H-NMR measurement results are shown in Figure 3. 13 The results of C-NMR are shown in Figure 4. 1The H-NMR measurement results are shown in Figure 5. 13 The results of C-NMR are shown in Figure 6. In the chemical structures represented by formulas (1A) and (1B), it was found that the peak of the proton bonded to the carbon atom directly bonded to the norbornene ring of the double bond of the vinyl group (the carbon atom represented by the integer 2 in a circle in Figure 3 or Figure 5) was split. From this data, it was inferred that there exist two stereoisomers: an isomer in which the vinyl group bonded to the norbornene ring extends forward into the paper in the same manner as the crosslinked structure of the norbornene ring (syn isomer), and an isomer in which the vinyl group bonded to the norbornene ring extends backward into the paper in the opposite direction to the crosslinked structure of the norbornene ring (anti isomer). Similarly, it is presumed that there are two stereoisomers: an isomer in which the sulfur atom bonded to the norbornene ring extends forward toward the paper in the same manner as the bridged structure of the norbornene ring (syn isomer), and an isomer in which the sulfur atom bonded to the norbornene ring extends backward toward the paper in the opposite direction to the bridged structure of the norbornene ring (anti isomer). From the above, it is presumed that the obtained silane compound is a mixture of eight stereoisomers represented by the following formula. [ka]

[0088] [Preparation Example 2: Synthesis of silane compound (VNB-2SSi)] A 50mL three-neck flask was fitted with a ball stopper, a three-way cock connected to a vacuum / dry nitrogen line, and a septum, then a stirrer bar was placed in the flask, and the system was degassed and replaced with nitrogen 10 times while heating with a dryer, creating a nitrogen atmosphere at normal pressure. 5.2g (0.043mol) of 2-vinylnorbornene (VNB) and 20.3g (0.085mol) of mercaptopropyltriethoxysilane were injected into the flask using a syringe, and 0.14g (0.85mmol) of azobisisobutyronitrile was added under a nitrogen atmosphere, followed by nitrogen bubbling for 20 minutes. After sealing the connections with silicone grease, the flask was immersed in an oil bath, the bath temperature was gradually raised to 50°C, and the reaction was allowed to proceed for 13 hours, after which it was further raised to 70°C and allowed to proceed for 5 hours. Next, mercaptopropyltriethoxysilane was added twice in total (first addition: 0.10 g (0.85 mmol), second addition: 0.26 g (2.13 mmol)), and each reaction was carried out at 70°C for 5 hours. After that, the mixture was allowed to cool to room temperature, and 25.0 g of the desired colorless to pale yellow clear liquid was obtained. The obtained compound 1 The results of H-NMR are shown in FIG. 1 H-NMR measurement confirmed that the silane introduction rate was 100%, and that the double bonds in both the norbornene ring and the vinyl group had disappeared. [ka]

[0089] [Detection of stereoisomers of silane compounds] The silane compound (VNB-2SSi) obtained above 1 The results of H-NMR are shown in FIG. 1The results of H-NMR measurements confirmed that the double bond of the vinyl group had disappeared. Here, it is presumed that the silane compound (VNB-2SSi) is obtained by further reacting the vinyl group of the eight stereoisomers (1-adducts) of the silane compound (VNB-SSi) synthesized in Preparation Example 1 with mercaptosilane to generate a 2-adduct. In this case, it is presumed that the addition to the vinyl group only occurs at the 1-position (outside) of the vinyl group, which has less steric hindrance, and that the stereoisomerism of the silane compound (VNB-SSi) is maintained as it is in the addition to the vinyl group. From the above, it is presumed that the obtained silane compound (VNB-2SSi) is a mixture of eight stereoisomers represented by the following formula. [ka]

[0090] [Example 1-1] (Preparation of silane coupling agent composition, rubber composition, and rubber sheet) First, the entire amount of the silane compound (VNB-2SSi) synthesized above and the entire amount of the protein denaturant 1 (urea) were mixed to obtain a silane coupling agent composition. Next, the following components were kneaded using a 100 mL kneader (Labo Plastomill manufactured by Toyo Seiki Seisakusho Co., Ltd.) to obtain a rubber composition. The details of the kneading operation performed are as follows (i) to (iii). (i) Mixer kneading: Natural rubber was put into an internal pressure kneader heated to 150 ° C., and masticated at 30 rpm for 1 minute, and then 1 / 2 of the mixture of silica, zinc oxide, stearic acid, and antioxidant was measured and the entire amount of the silane coupling agent composition prepared above was put in, and the rotation speed was increased to 50 rpm and kneaded for 1 minute 30 seconds.Furthermore, the remaining 1 / 2 amount of the mixture of silica, zinc oxide, stearic acid, and antioxidant was added, and kneading was continued for 1 minute 30 seconds, and then the ram (floating weight) was raised and the powder of the mixture of silica, zinc oxide, stearic acid, and antioxidant attached to the periphery was put into the kneaded product using a brush, and kneading was continued for another 1 minute, and then the ram was raised again and the powder of the mixture of silica, zinc oxide, stearic acid, and antioxidant attached to the periphery was put into the kneaded product using a brush, and kneaded for another 3 minutes and released. (ii) Remilling: In order to improve the dispersion of the silica, the kneaded material was discharged into an internal pressure kneader heated to 120°C, and after the temperature had sufficiently decreased, it was further kneaded at 50 rpm for 2 minutes and then discharged. (iii) Roll mixing (addition of vulcanization system): After the temperature had sufficiently dropped after release, sulfur, a vulcanization accelerator, etc. were added to the above-mentioned kneaded material using two rolls, and the mixture was kneaded to obtain a rubber composition. Thereafter, the obtained unvulcanized rubber composition was placed in a mold (150 mm×150 mm×2 mm) and heated and pressed at 150° C. for 25 minutes to obtain a vulcanized rubber sheet having a thickness of 2 mm. Natural rubber (made in Thailand, RSS#3) 100 parts by weight Silica AQ (manufactured by Tosoh Corporation, product name: Nipsil AQ) 40 parts by weight 3 parts by weight of zinc oxide No. 3 (manufactured by Toho Zinc Co., Ltd., product name: Ginrei R) Stearic acid (manufactured by Shin Nippon Rika, product name: Stearic Acid 300) 1 part by weight Anti-aging agent (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Nocrac 6C) 1 part by weight Protein denaturant 1 (manufactured by Wako Pure Chemical Industries, Ltd., product name: urea) 1 part by mass ·Silane compound (VNB-2SSi) (Preparation example 2) 3.20 parts by mass Sulfur (Hosoi Chemicals, 5% oil-treated sulfur) 2.76 parts by weight Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccela CZ) 1 part by mass Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccelaer D) 0.5 parts by mass

[0091] [Example 1-2] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 1-1, except that the amount of urea added was changed to 2 parts by mass.

[0092] [Examples 1-3] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 1-1, except that the amount of urea added was changed to 0.5 parts by mass.

[0093] [Examples 1-4] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 1-1, except that the amount of urea added was changed to 3 parts by mass.

[0094] [Examples 1-5] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 1-1, except that the amount of urea added was changed to 5 parts by mass.

[0095] [Comparative Example 1-1] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 1-1, except that the silane compound (VNB-2SSi) was not added, 3.20 parts by mass of another silane compound (Si69) was added, and the amount of sulfur added was changed to 2.00 parts by mass.

[0096] [Comparative Example 1-2] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 1-1, except that urea was not added.

[0097] [Physical property evaluation] The physical properties of the rubber compositions and rubber sheets obtained in the above Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-2 were evaluated by the following methods.

[0098] (hardness) Three of the rubber sheets (2 mm thick) obtained in Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-2 were stacked, and the JIS-A strength was measured in accordance with JIS K6353 (published in 2012). The higher the measurement result, the higher the hardness of the rubber sheet and the more excellent the steering stability as a tire.

[0099] (Viscoelasticity) Using a viscoelasticity measuring device (REOGEL E-4000 manufactured by UBM), tan δ was measured at measurement temperatures of 0° C. and 60° C. for the rubber sheets obtained in Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-2 under conditions of strain of about 0.1% and frequency of 10 Hz in accordance with JIS K 6394, and the tan δ balance (= tan δ (0° C.) / tan δ (60° C.)) was calculated from this value. A larger tan δ balance means that the viscoelasticity characteristics of the rubber sheet are more excellent, and that the balance between wet grip properties and fuel economy as a tire is more excellent.

[0100] (Scorch resistance) In accordance with JIS K6300, a rotorless Mooney measuring instrument manufactured by Toyo Seiki Co., Ltd. was used to measure the time t5 required for the viscosity to rise by 5 Mooney units from the minimum viscosity Vm after preheating the unvulcanized rubber composition at 125°C for 1 minute. A larger measurement result indicates a longer scorch time and better processability of the rubber composition.

[0101] The above measurement results and calculation results (tan δ balance) are shown in Table 1. Each measurement value and calculation value is expressed as an index, with each value in Comparative Example 1-1 being set at 100.

[0102] [Table 1]

[0103] From the results of Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-2, it was found that the rubber composition containing natural rubber had improved scorch resistance, and furthermore, the hardness and viscoelasticity of the rubber sheet were improved by using the silane coupling agent composition containing the silane compound (VNB-2SSi) and the protein denaturant 1. Therefore, it was found that the use of the silane coupling agent composition and the rubber composition of the present invention improves the processability of the rubber, and furthermore, it is possible to manufacture a tire that is excellent in practical handling stability and has an excellent balance between wet grip properties and low fuel consumption.

[0104] [Example 2-1] (Preparation of silane coupling agent composition, rubber composition, and rubber sheet) First, the entire amount of the silane compound (VNB-2SSi) synthesized above and the entire amount of the protein denaturant 2 (50% aqueous glutaraldehyde solution) were mixed to obtain a silane coupling agent composition. Next, the following components were kneaded using a 100 mL kneader (Labo Plastomill manufactured by Toyo Seiki Seisakusho Co., Ltd.) to obtain a rubber composition. The details of the kneading operation performed are as follows (i) to (iii). (i) Mixer kneading: Natural rubber was put into an internal pressure kneader heated to 150 ° C., and masticated at 30 rpm for 1 minute, and then 1 / 2 of the mixture of silica, zinc oxide, stearic acid, and antioxidant was measured and the entire amount of the silane coupling agent composition prepared above was put in, and the rotation speed was increased to 50 rpm and kneaded for 1 minute 30 seconds.Furthermore, the remaining 1 / 2 amount of the mixture of silica, zinc oxide, stearic acid, and antioxidant was added, and kneading was continued for 1 minute 30 seconds, and then the ram (floating weight) was raised and the powder of the mixture of silica, zinc oxide, stearic acid, and antioxidant attached to the periphery was put into the kneaded product using a brush, and kneading was continued for another 1 minute, and then the ram was raised again and the powder of the mixture of silica, zinc oxide, stearic acid, and antioxidant attached to the periphery was put into the kneaded product using a brush, and kneaded for another 3 minutes and released. (ii) Remilling: In order to improve the dispersion of the silica, the kneaded material was discharged into an internal pressure kneader heated to 120°C, and after the temperature had sufficiently decreased, it was further kneaded at 50 rpm for 2 minutes and then discharged. (iii) Roll mixing (addition of vulcanization system): After the temperature had sufficiently dropped after release, sulfur, a vulcanization accelerator, etc. were added to the above-mentioned kneaded material using two rolls, and the mixture was kneaded to obtain a rubber composition. Thereafter, the obtained unvulcanized rubber composition was placed in a mold (150 mm×150 mm×2 mm) and heated and pressed at 150° C. for 25 minutes to obtain a vulcanized rubber sheet having a thickness of 2 mm. Natural rubber (made in Thailand, RSS#3) 100 parts by weight Silica AQ (manufactured by Tosoh Corporation, product name: Nipsil AQ) 40 parts by weight 3 parts by weight of zinc oxide No. 3 (manufactured by Toho Zinc Co., Ltd., product name: Ginrei R) Stearic acid (manufactured by Shin Nippon Rika, product name: Stearic Acid 300) 1 part by weight Anti-aging agent (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Nocrac 6C) 1 part by weight Protein denaturant 2 (manufactured by Tokyo Chemical Industry Co., Ltd., product name: glutaraldehyde 50% aqueous solution) 2 parts by mass ·Silane compound (VNB-2SSi) (Preparation example 2) 3.20 parts by mass Sulfur (Hosoi Chemicals, 5% oil-treated sulfur) 2.76 parts by weight Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccela CZ) 1 part by mass Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccelaer D) 0.5 parts by mass

[0105] [Example 2-2] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-1, except that protein denaturant 2 was not added and 1 part by mass of protein denaturant 3 (manufactured by Tokyo Chemical Industry Co., Ltd., product name: dimethyl suberimidate dihydrochloride) was added.

[0106] [Example 2-3] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-1, except that protein denaturant 2 was not added and 1 part by mass of protein denaturant 4 (manufactured by Tokyo Chemical Industry Co., Ltd., product name: sodium dodecyl sulfate) was added.

[0107] [Example 2-4] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-1, except that protein denaturant 2 was not added and 1 part by mass of protein denaturant 5 (manufactured by Tokyo Chemical Industry Co., Ltd., product name: guanidine hydrochloride) was added.

[0108] [Comparative Example 2-1] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-1, except that the silane compound (VNB-2SSi) was not added, 3.20 parts by mass of another silane compound (Si69) was added, and the amount of sulfur added was changed to 2.00 parts by mass.

[0109] [Comparative Example 2-2] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-2, except that the silane compound (VNB-2SSi) was not added, 3.20 parts by mass of another silane compound (Si69) was added, and the amount of sulfur added was changed to 2.00 parts by mass.

[0110] [Comparative Example 2-3] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-3, except that the silane compound (VNB-2SSi) was not added, 3.20 parts by mass of another silane compound (Si69) was added, and the amount of sulfur added was changed to 2.00 parts by mass.

[0111] [Comparative Example 2-4] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 2-4, except that the silane compound (VNB-2SSi) was not added, 3.20 parts by mass of another silane compound (Si69) was added, and the amount of sulfur added was changed to 2.00 parts by mass.

[0112] [Comparative Example 2-5] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Comparative Example 2-1, except that the protein denaturant 2 was not added.

[0113] [Physical property evaluation] The viscoelasticity of the rubber sheets obtained in the above Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-5 and the scorch resistance of the rubber compositions were evaluated by the above methods in the same manner as in Example 1-1. The above measurement results and calculation results (tan δ balance) are shown in Table 2. Each measured value and each calculated value is expressed as an index, with the value in Comparative Example 2-5 being set at 100.

[0114] [Table 2]

[0115] From the results of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-5, it was found that the use of the silane coupling agent composition containing the silane compound (VNB-2SSi) and the protein denaturants 2 to 5 improved the scorch resistance of the rubber composition containing natural rubber, and further improved the viscoelastic properties of the rubber sheet. Therefore, it was found that the use of the silane coupling agent composition and rubber composition of the present invention improved the processability of the rubber, and furthermore, in practical terms, made it possible to manufacture a tire that had an excellent balance between wet grip properties and low fuel consumption.

[0116] [Example 3-1] (Preparation of silane coupling agent composition, rubber composition, and rubber sheet) First, the entire amount of the silane compound (VNB-2SSi) synthesized above and the entire amount of the protein denaturant 1 (urea) were mixed to obtain a silane coupling agent composition. Next, the following components were kneaded using a 100 mL kneader (Labo Plastomill manufactured by Toyo Seiki Seisakusho Co., Ltd.) to obtain a rubber composition. The details of the kneading operation performed are as follows (i) to (iii). (i) Mixer kneading: Natural rubber was put into an internal pressure kneader heated to 150 ° C., and masticated at 30 rpm for 1 minute, and then 1 / 2 of the mixture of silica, zinc oxide, stearic acid, and antioxidant was measured and the entire amount of the silane coupling agent composition prepared above was put in, and the rotation speed was increased to 50 rpm and kneaded for 1 minute 30 seconds.Furthermore, the remaining 1 / 2 amount of the mixture of silica, zinc oxide, stearic acid, and antioxidant was added, and kneading was continued for 1 minute 30 seconds, and then the ram (floating weight) was raised and the powder of the mixture of silica, zinc oxide, stearic acid, and antioxidant attached to the periphery was put into the kneaded product using a brush, and kneading was continued for another 1 minute, and then the ram was raised again and the powder of the mixture of silica, zinc oxide, stearic acid, and antioxidant attached to the periphery was put into the kneaded product using a brush, and kneaded for another 3 minutes and released. (ii) Remilling: In order to improve the dispersion of the silica, the kneaded material was discharged into an internal pressure kneader heated to 120°C, and after the temperature had sufficiently decreased, it was further kneaded at 50 rpm for 2 minutes and then discharged. (iii) Roll mixing (addition of vulcanization system): After the temperature had sufficiently dropped after release, sulfur, a vulcanization accelerator, etc. were added to the above-mentioned kneaded material using two rolls, and the mixture was kneaded to obtain a rubber composition. Thereafter, the obtained unvulcanized rubber composition was placed in a mold (150 mm×150 mm×2 mm) and heated and pressed at 160° C. for 30 minutes to obtain a vulcanized rubber sheet having a thickness of 2 mm. Styrene-butadiene rubber (manufactured by ZS Elastomers, product name: NS616) 70 parts by weight -Butadiene rubber (manufactured by Ube Industries, product name: UBEPOL BR150) 30 parts by mass Silica AQ (manufactured by Tosoh Corporation, product name: Nipsil AQ) 80 parts by weight 3 parts by weight of zinc oxide No. 3 (manufactured by Toho Zinc Co., Ltd., product name: Ginrei R) Stearic acid (manufactured by Shin Nippon Rika, product name: Stearic Acid 300) 1 part by weight Anti-aging agent (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Nocrac 6C) 1 part by weight Protein denaturant 1 (manufactured by Wako Pure Chemical Industries, Ltd., product name: urea) 1 part by mass ·Silane compound (VNB-2SSi) (Preparation example 2) 6.40 parts by mass Sulfur (Hosoi Chemicals, 5% oil-treated sulfur) 2.52 parts by weight Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccela CZ) 2.3 parts by weight Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccelaer D) 1.1 parts by mass

[0117] [Example 3-2] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 3-1, except that the amount of urea added was changed to 2 parts by mass.

[0118] [Comparative Example 3-1] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 3-1, except that the silane compound (VNB-2SSi) was not added, 6.40 parts by mass of another silane compound (Si69) was added, and the amount of sulfur added was changed to 1.00 parts by mass.

[0119] [Comparative Example 3-2] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Comparative Example 3-1, except that urea was not added.

[0120] [Comparative Example 3-3] A silane coupling agent composition, a rubber composition, and a rubber sheet were obtained in the same manner as in Example 3-1, except that urea was not added.

[0121] [Physical property evaluation] The hardness and viscoelasticity of the rubber sheets obtained in the above Examples 3-1 to 3-2 and Comparative Examples 3-1 to 3-3 were evaluated by the above methods in the same manner as in Example 1-1. The above measurement results and calculation results (tan δ balance) are shown in Table 3. Each measured value and each calculated value is expressed as an index, with the value in Comparative Example 3-1 being set to 100.

[0122] [Table 3]

[0123] From the results of Examples 3-1 to 3-2 and Comparative Examples 3-1 to 3-3, it was found that the hardness and viscoelasticity of the rubber sheet were improved by using a silane coupling agent composition containing a specific silane compound (VNB-2SSi) and urea. Therefore, it was found that the rubber composition containing the silane coupling agent composition of the present invention can be used to manufacture a tire that is excellent in practical handling stability and has an excellent balance between wet grip properties and low fuel consumption.

Claims

1. The following formula (1): 【Chemistry 1】 [In the formula, Each R １ , R ２ and R ３ each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; Each L is independently a sulfur-containing hydrocarbon group; a is an integer of 0 or 1; b is an integer of 0 or 1; Each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R ４ , R ５ , R ６ and R ７ represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R ４ Or R ５ and R ６ Or R ７ One of them is -(CH ２ ) ｆ - may form a bridge structure represented by f is an integer equal to 1; R ８ , R ９ , R １０ and R １１ represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R ８ Or R ９ and R １０ Or R １１ One of them is -(CH ２ ) ｇ - may form a bridge structure represented by g is an integer equal to 1; However, at least one of a bridge structure represented by -(CH 2 ) f - and a bridge structure represented by -(CH 2 ) g - is present; R １２ , R １３ and R １４ each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms. A silane compound represented by the formula: a protein denaturant which is at least one selected from the group consisting of carbamide compounds, guanidine compounds, surfactants, glutaraldehyde, dimethyl suberimidate dihydrochloride, β-mercaptoethanol, and dithiothreitol; 1. A silane coupling agent composition comprising:

2. The silane compound is represented by the following formula (2): 【Chemistry 2】 [In the formula, Each R １ , R ２ and R ３ each independently represents a hydrocarbon group which may contain an oxygen atom or a nitrogen atom, or a hydrogen atom; h is an integer from 1 to 10; m is an integer from 1 to 10, a is an integer of 0 or 1; b is an integer of 0 or 1; Each c is independently an integer of 0 or 1; Each d is independently an integer of 0 or 1; e is an integer from 0 to 5; R ４ , R ５ , R ６ and R ７ represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R ４ Or R ５ and R ６ Or R ７ One of them is -(CH ２ ) ｆ - may form a bridge structure represented by f is an integer equal to 1; R ８ , R ９ , R １０ and R １１ represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms, or R ８ Or R ９ and R １０ Or R １１ One of them is -(CH ２ ) ｇ - may form a bridge structure represented by g is an integer equal to 1; However, at least one of a bridge structure represented by -(CH 2 ) f - and a bridge structure represented by -(CH 2 ) g - is present; R １２ , R １３ and R １４ each independently represents a hydrogen atom, a methyl group, or an alkyl group having 2 to 10 carbon atoms. The silane coupling agent composition according to claim 1, wherein the compound is represented by the formula:

3. 3. The silane coupling agent composition according to claim 1, wherein the protein denaturing agent is at least one selected from the group consisting of carbamide compounds, guanidine compounds, and surfactants.

4. The silane coupling agent composition according to claim 3 , wherein the carbamide compound is urea.

5. The silane coupling agent composition according to any one of claims 1 to 4, which is used for natural rubber and / or synthetic isoprene rubber.

6. A rubber composition comprising the silane coupling agent composition according to any one of claims 1 to 5, a diene rubber, and silica, The rubber composition has a protein denaturant content of 0.01 to 10 parts by mass based on 100 parts by mass of the diene rubber.

7. The rubber composition of claim 6 , wherein the diene-based rubber comprises natural rubber and / or synthetic isoprene rubber.

8. The rubber composition according to claim 6 or 7, wherein the content of the silica is 5 to 100 parts by mass based on 100 parts by mass of the diene rubber.

9. The rubber composition according to any one of claims 6 to 8, which is used for a tire.

10. A crosslinked product of the rubber composition according to any one of claims 6 to 9.

11. A pneumatic tire comprising a tire tread made of the crosslinked product according to claim 10.

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