JP6067435B2 - Rubber composition and pneumatic tire - Google Patents

Description

  The present invention relates to a rubber composition and a pneumatic tire using the same.

  Generally, diene rubber is used as a rubber component in a rubber composition, and a reinforcing filler such as carbon black or silica is blended as a reinforcing agent. Such rubber compositions, particularly tire rubber compositions, are required to improve in a well-balanced manner the heat generation characteristics that contribute to low fuel consumption and the low-temperature characteristics that contribute to grip performance (wet grip performance) on wet road surfaces.

  However, among reinforcing fillers, silica is difficult to disperse in the diene rubber, and problems such as poor dispersion tend to occur particularly when the filling amount is high. Therefore, various silane coupling agents having reactivity or interaction with both diene rubber and silica are used, but the performance of silica has not been fully exploited. For example, polysulfide silane, mercaptosilane, and protected mercaptosilane obtained by blocking a mercapto group with a carboxylic acid have been used. These are all supposed to react under heat and basic conditions. On the other hand, an organic silane having a monosulfide bond (—C—S—C—) is relatively stable thermally, and therefore generally difficult to react directly with a diene rubber.

  Patent Documents 1 to 3 disclose a method for producing a silanized cyclic core polysulfide compound or a silylated core polysulfide compound, and a rubber composition using the same. However, the organic silanes disclosed in these documents have a plurality of polysulfide groups, and the point of blending an organic silane having a monosulfide bond is not disclosed.

  On the other hand, Patent Document 4 discloses an etheralkoxy sulfur silane that releases ether alcohol during rubber compounding, and the silane transesterifies a polysulfide silane coupling agent or a mercaptosilane coupling agent with ether alcohol. It is manufactured by. Patent Document 5 discloses that a rubber composition is blended with a silane coupling agent obtained by blocking mercaptosilane with a compound having a vinyl ether group.

JP 2010-514766 gazette Special table 2010-514765 gazette Special table 2010-514907 JP-T-2006-523259 International Publication No. 2007/132909

  An object of this invention is to provide the rubber composition which can improve the dispersibility of the silica which is a reinforcement filler, and can improve a heat_generation | fever characteristic and a low temperature characteristic with sufficient balance in view of the above point.

The rubber composition according to the present invention comprises 100 parts by mass of a diene rubber, 20 to 150 parts by mass of silica, and 2 organosilanes represented by the following general formulas (1) and / or (2) with respect to the silica mass -20 mass% is formed.

In the formula, X ¹ , X ² and X ³ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. One of A ¹ and A ² is —C _x H _2x —SiR ¹ R ² R ³ , and the other is —C _m H _n —Z or —C (═O) —R ⁴ . R ¹ , R ² and R ³ are each an alkyl group or alkoxy group having 1 to 3 carbon atoms, and at least one is an alkoxy group. x is an integer of 2-4. m is an integer of 1 to 22, and n is an integer of 2 to 44. Z is a mercapto group, a carboxyl group, a hydroxyl group or an amino group. R ⁴ is an aliphatic or aromatic hydrocarbon group having 1 to 18 carbon atoms. —SA ² is bonded to the 3rd or 4th carbon atom of the cyclohexyl group, and may be a mixture of those bonded to the 3rd position and those bonded to the 4th position.

  The pneumatic tire according to the present invention is formed using the rubber composition.

  According to the present invention, not only can the low temperature characteristics be improved by using a novel organic silane having the above-mentioned specific structure as a silane coupling agent, but also the high temperature heat generation characteristics can be improved. For example, when used in a pneumatic tire, wet skid performance and fuel efficiency can be improved in a well-balanced manner.

  Hereinafter, matters related to the implementation of the present invention will be described in detail.

  The rubber composition according to the present embodiment is obtained by blending an organic silane having a specific structure as a silane coupling agent with silica as a reinforcing filler with respect to a diene rubber that is a rubber component.

  Examples of the diene rubber as the rubber component include natural rubber (NR), synthetic isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile rubber (NBR), and chloroprene rubber (CR). , Butyl rubber (IIR), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, and the like. These may be used alone or in combination of two or more. Can be used. Among these, at least one selected from the group consisting of NR, BR and SBR is preferable.

In addition, these diene rubbers may be those whose main chain or terminal is modified, for example, in the molecular terminal or molecular chain of NR, IR, BR, SBR, an alkoxy group, a carbonyl group, At least one functional group such as a hydroxyl group, an amino group, and an epoxy group (a functional group that interacts with a silanol group of silica) may be introduced. When using the modified diene rubber having such a functional group, also interact with the -C m _H n _-Z organosilane used as the silane coupling agent can be expected. For example, when Z is a carboxyl group, a hydroxyl group, or an amino group, at least one selected from the group consisting of the above functional groups of the modified diene rubber (that is, an alkoxy group, a carbonyl group, a hydroxyl group, an amino group, and an epoxy group) functional groups), it is possible to interact with the -C m _H n _-Z organosilane, it is possible to further improved properties of the rubber composition. From such a viewpoint, as a preferred embodiment, the proportion of the modified diene rubber in the rubber component is preferably 30% by mass or more, more preferably 50% by mass or more. You may comprise only a modified diene rubber.

The silica as the reinforcing filler is not particularly limited, but wet silica (hydrous silicic acid) is preferable. Colloidal properties of the silica is also not particularly limited, a nitrogen adsorption specific surface area (BET) 150~250m ² / g by BET method is preferably used, more preferably 180~230m ² / g. The BET of silica is measured according to the BET method described in ISO 5794.

  It is preferable that the compounding quantity of a silica is 20-150 mass parts with respect to 100 mass parts of said diene rubbers, More preferably, it is 30-120 mass parts, More preferably, it is 40-100 mass parts.

  In the rubber composition according to the present embodiment, as the filler, various inorganic fillers such as carbon black, titanium oxide, aluminum silicate, clay, or talc may be used in combination in addition to the silica. Two or more of these may be used in combination. Among these, carbon black is preferable as a filler used in combination with silica. In addition, it is preferable that the total compounding quantity of the inorganic filler containing a silica is 20-180 mass parts with respect to 100 mass parts of said diene rubbers, More preferably, it is 30-150 mass parts, More preferably, it is 50. -120 parts by mass. When other inorganic fillers are used in combination, it is preferable that silica is the main component, that is, 50% by mass or more of the inorganic filler is silica.

The organic silane blended as the silane coupling agent in the present embodiment is a silane compound represented by the following formula (1) and / or (2). That is, the silane coupling agent is represented by the silane compound represented by the formula (1), the silane compound represented by the formula (2), or the silane compound represented by the formula (1) and the formula (2). It may be a mixture with a silane compound.

In these formulas (1) and (2), X ¹ , X ² and X ³ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom, a methyl group or ethyl. A group, more preferably a hydrogen atom or a methyl group. In one embodiment, X ² is preferably a hydrogen atom from the viewpoint of controlling the order of reactions in the ene-thiol reaction described below.

In formulas (1) and (2), ^one of A ¹ and A ² is —C _x H _2x —SiR ¹ R ² R ³ and the other is —C _m H _n —Z or —C (= O) —R ⁴ . Incidentally, described later ene - in thiol-reactive, given that tends to be generated towards the ^{-S-A 1} than ^{-S-A 2, A 1} is located in the _{^{-C x H 2x -SiR 1 R 2}} R 3 , A ² is preferably —C _m H _n —Z or —C (═O) —R ⁴ in order to more surely incorporate the binding site with silica, but is not particularly limited. Absent.

Said ^R 1, ^{R 2} and ^{R 3} are each an alkyl group or an alkoxy group having 1 to 3 carbon atoms, at least one is an alkoxy group. As the alkyl group, for example, a methyl group or an ethyl group is preferable. As the alkoxy group, for example, a methoxy group or an ethoxy group is preferable. Two or more of R ¹ , R ² and R ³ are preferably alkoxy groups, and more preferably all three are alkoxy groups. That is, the alkoxysilyl group represented by -SiR ¹ R ² R ³ is preferably an alkyl dialkoxysilyl group or a trialkoxysilyl group, more preferably a triethoxysilyl group or a trimethoxysilyl group. An alkoxysilyl group.

Said x is an integer of 2-4. Accordingly, —C _x H _2x — represents an alkylene group having 2 to 4 carbon atoms (alkanediyl group), and specific examples include an ethylene group, a propylene group, and a butylene group, which are linear or branched. It may be a shape.

Z is a functional group selected from a mercapto group (—SH), a carboxyl group (—COOH), a hydroxyl group (—OH), or an amino group. By incorporating -C m _H n _-Z having such a functional group, to silica or a diene-based rubber can increase the reactivity or affinity can further improve the properties of the rubber composition. The amino group includes not only a primary amino group (—NH ₂ ) but also a secondary or tertiary amino group (—NHR, —NRR ′. Here, R and R ′ are alkyl groups, preferably each Independently an alkyl group having 1 to 10 carbon atoms.

The m is an integer of 1 to 22, and n is an integer of 2 to 44. Accordingly, —C _m H _n — is a divalent hydrocarbon group having 1 to 22 carbon atoms, which may be linear or branched, saturated or unsaturated, and in the case of unsaturation, The position and number are not particularly limited. -C _m H _n - is preferably an alkylene group having 1 to 18 carbon atoms, more preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 8 carbon atoms.

R ⁴ is an aliphatic or aromatic hydrocarbon group having 1 to 18 carbon atoms, and more preferably an alkyl group or aryl group having 1 to 8 carbon atoms. When —S—C (═O) —R ⁴ is incorporated into an organosilane, the bond between the sulfur atom and the carbonyl group is easily broken by heat, so that the reactivity with the diene rubber can be improved. it can.

In formulas (1) and (2), —SA ² is bonded to the carbon atom at the 3rd or 4th position of the cyclohexyl group, and is a mixture of those bonded at the 3rd position and those bonded at the 4th position. Also good. That is, the organosilane according to the embodiment may be bonded to the 3rd position in the formula (1), may be bonded to the 4th position, or may be a mixture of both. In the formula (2), it may be bonded at the 3-position, may be bonded at the 4-position, may be a mixture of the two, or these formulas (1) and The mixture which consists of 2 or more types of combinations of the compound of (2) may be sufficient.

The organosilane has a monosulfide bond (—C—S—C—) in the molecule, and this part is cleaved by heat to react with the diene rubber, or at least has a monosulfide bond. It is thought that it interacts with diene rubber. The organosilane has an alkoxysilyl group in the molecule and can react with silica at this portion. Therefore, since diene rubber and silica can be bonded (crosslinked), the dispersibility of silica can be improved and the characteristics of the rubber composition can be improved by using it as a silane coupling agent. Moreover, organic silane may increase the reactivity or affinity has _-C m _H n -Z or -C (= O) -R ⁴ in a molecule, silica or diene rubber Therefore, the characteristic improvement effect of the rubber composition can be enhanced. Although the reason why the organic silane is a monosulfide silane and exhibits a good coupling effect is not necessarily clear, it is considered that it has a unique structure including a cyclohexane ring in the molecule. In addition, since the organic silane has a monosulfide bond, scorch hardly occurs and the scorch resistance can be improved.

In one embodiment, in the above formulas (1) and (2), when the organosilane is X ¹ is an alkyl group having 1 to 3 carbon atoms, —SA ² is a carbon atom at the 3-position of the cyclohexyl group. May be combined. That is, in this case, the organosilane is a compound represented by the following formula (1-1) and / or (2-1).

In the formulas (1-1) and (2-1), X ¹¹ is an alkyl group having 1 to 3 carbon atoms, and X ² , X ³ , A ¹ and A ² are the above formulas (1) and (2), respectively. The same as X ² , X ³ , A ¹ and A ² in them.

In another embodiment, in the above formulas (1) and (2), when X ¹ is a hydrogen atom, —SA ² is bonded to the carbon atom at the 3-position or the 4-position of the cyclohexyl group, and 3 It may be a mixture of those bonded to the position and those bonded to the 4-position. That is, in this case, the organosilane is at least one selected from the group consisting of compounds represented by the following formulas (1-2), (1-3), (2-2), and (2-3). Yes, as a more detailed embodiment, a mixture of a compound of formula (1-2) and a compound of formula (1-3), or a compound of formula (2-2) and a compound of formula (2-3) It is a mixture of

In the formulas (1-2), (1-3), (2-2) and (2-3), X ² , X ³ , A ¹ and A ² are respectively in the above formulas (1) and (2). The same as X ² , X ³ , A ¹ and A ² .

Although the manufacturing method of this organosilane is not specifically limited, For example, it represents with the compound represented by following formula (3), the compound represented by following formula (4), and following formula (5) or (6). It can be synthesized by reacting with a compound.

In the formulas (3) to (6), X ¹ , X ² , X ³ , R ¹ , R ² , R ³ , R ⁴ , Z, x, m and n are in the above formulas (1) and (2), respectively. X ¹ , X ² , X ³ , R ¹ , R ² , R ³ , R ⁴ , Z, x, m and n are the same.

The compound represented by the formula (3) is a compound having two carbon-carbon double bonds, and the compounds represented by the formulas (4) to (6) are compounds having a mercapto group. In this reaction, the mercapto group of the compounds of formulas (4) to (6) is bonded to the two carbon-carbon double bonds of the compound of formula (3) by an ene-thiol reaction. Thus, by using the ene-thiol reaction, the above-mentioned organosilane can be produced easily and with a high yield. Note that whether the compound of the above formula (1) or the compound of the formula (2) is generated depends on the types of X ² and X ^{3 in} the formula (3), and the compound of the formula (1) and the formula ( Either one of the compounds of 2) or a mixture of both is produced.

In the present embodiment, in order to produce an organosilane having an alkoxysilyl group, a compound represented by the formula (4) is used as a compound having a mercapto group. Moreover, in order to improve the reactivity or affinity with silica or diene rubber, a compound represented by the formula (5) or (6) is also used as the compound having a mercapto group. Therefore, ^one of A ¹ and A ² is —C _x H _2x —SiR ¹ R ² R ³ , and the other is —C _m H _n —Z or —C (═O) —R ⁴ . In this case, the compound of formula (4) may be reacted first with the compound of formula (3), and then the compound of formula (5) or (6) may be reacted with the obtained compound. The compound of formula (5) or (6) may be reacted first, and then the compound of formula (4) may be reacted with the obtained compound. According to one embodiment, the compound of formula (3) and the compound of formula (4) are reacted in equimolar amounts, and then the compound of formula (5) or (6) is reacted in equimolar amounts. May be. In the compound of formula (3), the substituent —CX ³ ═CHX ² is more reactive with respect to the ene-thiol reaction than the carbon-carbon double bond in the cyclic part of cyclohexene. Therefore, by reacting the compound of formula (4) first, an alkoxysilyl group that is a binding site with silica can be more reliably incorporated into the molecule.

Specific examples of the compound of formula (3) include 4-vinyl-1-cyclohexene or limonene (that is, 1-methyl-4- (1-methylethenyl) cyclohexene). Here, when limonene is used as the compound, a compound represented by the above formula (1-1) and / or (2-1) is obtained by an ene-thiol reaction, and particularly in the formula (1-1). The compound represented is obtained (wherein X ¹¹ is a methyl group, X ² is a hydrogen atom, and X ³ is a methyl group). In addition, when 4-vinyl-1-cyclohexene is used, at least one compound represented by the above formula (1-2), (1-3), (2-2) or (2-3) In particular, a mixture of the compound of formula (2-2) and the compound of formula (2-3) is obtained (wherein X ² and X ³ are both hydrogen atoms).

  As the compound of the formula (4), various known mercaptosilane coupling agents can be used. Specific examples include (3-mercaptopropyl) triethoxysilane, (3-mercaptopropyl) trimethoxysilane, ( Examples include 3-mercaptopropyl) methyldimethoxysilane, (3-mercaptopropyl) dimethylmethoxysilane, or mercaptoethyltriethoxysilane.

Specific examples of the compound of the formula (5) include alkanedithiols such as 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, or 1,8-octanedithiol, thioglycolic acid, 3 -Mercaptocarboxylic acids such as mercaptopropionic acid, 4-mercaptobutanoic acid, 5-mercaptopentanoic acid, 6-mercaptohexanoic acid, 7-mercaptoheptanoic acid, 9-mercaptononanoic acid or 10-mercaptodecanoic acid, 2-hydroxy -1-ethanethiol, 6-hydroxy-1-hexanethiol, 8-hydroxy-1-octanethiol, or hydroxyalkanethiol such as 11-hydroxy-1-undecanethiol, 2-amino-1-ethanethiol, 6- Amino-1-hexanethiol, 8-amino 1-octane thiol, or 11-amino-1-like aminoalkanethiol such as undecane thiols. Incidentally, -C m _H n in formula (5) _- If the there is a double bond, ene with compounds among the formula (5) - but thiol reactive is concerned, the reaction system of the compound of formula (5) By gradually adding to the reaction, the reaction between the compounds of the formula (5) can be suppressed.

  Specific examples of the compound of formula (6) include thioacetic acid and thiobenzoic acid.

  In the ene-thiol reaction, a radical generator is preferably used as a reaction catalyst. However, it may be a radical reaction by irradiating with ultraviolet rays (UV). Examples of the radical generator include azo compounds and organic peroxides, and those that generate radicals by heat and those that generate radicals by light irradiation are included. Examples of the azo compound include azobisisobutyronitrile (AIBN), 1,1′-azobis (cyclohexanecarbonitrile) (ABCN), and the like. Examples of the organic peroxide include di-tert-butyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, and methyl ethyl ketone peroxide.

  More specifically, the ene-thiol reaction is performed by mixing the compound represented by the formula (3), the compounds represented by the formulas (4) to (6), and a radical generator together with an organic solvent such as toluene. However, it can be carried out by maintaining the conditions under which radicals are generated. Although it does not specifically limit, it is preferable that reaction temperature is 50-120 degreeC.

  It is preferable that the compounding quantity of the organosilane represented by the said Formula (1) and / or (2) is 2-20 mass% with respect to the said silica mass. That is, the compounding quantity of this organosilane is 2-20 mass parts with respect to 100 mass parts of silica. By setting it as such a compounding quantity, while being able to fully exhibit the addition effect, the deterioration of the scorch-proof performance can be suppressed. The amount of the organic silane is more preferably 5 to 15% by mass of the silica mass.

  In the rubber composition according to this embodiment, the silane coupling agent may be only the organic silane represented by the above formula (1) and / or (2), but other silane coupling agents are used in combination with this. May be. Other silane coupling agents are not particularly limited. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) tetrasulfide , Sulfide silane coupling agents such as bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) disulfide; (3-mercaptopropyl) trimethoxy Mercaptosilanes such as silane, (3-mercaptopropyl) triethoxysilane, (3-mercaptopropyl) methyldimethoxysilane, (3-mercaptopropyl) dimethylmethoxysilane, mercaptoethyltriethoxysilane Coupling agents; 3- octanoylthio-1-propyltriethoxysilane, 3- propionyl protected mercaptosilane coupling agents such as Lucio trimethoxysilane and the like, which may be used in combination of two or more. Thus, when using another silane coupling agent together, it is preferable that the total compounding quantity of a silane coupling agent is 3-20 mass% of silica mass, More preferably, it is 5-15 mass%. When other silane coupling agent is used in combination, the organic silane of the above formula (1) and / or (2) is the main component, that is, 50% by mass or more of the silane coupling agent is the organic silane. Preferably there is.

  The rubber composition according to the present embodiment is generally used in rubber compositions such as oil, zinc white, stearic acid, anti-aging agent, wax, vulcanizing agent, and vulcanization accelerator in addition to the above components. Various additives can be blended.

  Examples of the vulcanizing agent include sulfur or a sulfur-containing compound (for example, sulfur chloride, sulfur dichloride, polymer polysulfide, morpholine disulfide, and alkylphenol disulfide). Or it can use in combination of 2 or more types. Although the compounding quantity of a vulcanizing agent is not specifically limited, It is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of said diene rubbers, More preferably, it is 0.5-5 mass parts. is there.

  As said vulcanization accelerator, various vulcanization accelerators, such as a sulfenamide type | system | group, a thiuram type | system | group, a thiazole type | system | group, or a guanidine type | system | group, can be used, for example, any 1 type individually or in combination of 2 or more types. Can be used. The blending amount of the vulcanization accelerator is not particularly limited, but is preferably 0.1 to 7 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the diene rubber. It is.

  The rubber composition according to the present embodiment can be prepared by kneading according to a conventional method using a commonly used Banbury mixer, kneader, roll, or other mixer. That is, in the first mixing stage, the rubber component is added and mixed with silica and a silane coupling agent together with other additives excluding the vulcanizing agent and the vulcanization accelerator, and then the resulting mixture is finally mixed. A rubber composition can be prepared by adding and mixing a vulcanizing agent and a vulcanization accelerator in stages.

  The rubber composition thus obtained can be used for various rubber members for tires, vibration-proof rubbers, conveyor belts and the like. Preferably, it is used for tires, for various applications such as passenger cars, large tires for trucks and buses, tread parts, side wall parts, bead parts, tire cord covering rubber, etc. Can be applied to. That is, according to a conventional method, the rubber composition is molded into a predetermined shape by, for example, extrusion, and combined with other parts, and then vulcanized and molded at, for example, 140 to 180 ° C. to produce a pneumatic tire. can do. Among these, it is particularly preferable to use as a tire tread formulation.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Synthesis of organosilane>
[Synthesis Example 1]
150 g of (3-mercaptopropyl) triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), 85.7 g of limonene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2′-azobis (isobutyronitrile) (Wako Pure Chemical Industries, Ltd.) 8.99 g of Kogyo Co., Ltd. and 300 ml of toluene were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. Thereafter, the reaction solution was concentrated to obtain 227 g of a colorless liquid (yield: 97%). 150 g of the obtained compound, 60.2 g of 1,5-pentanedithiol (manufactured by Wako Pure Chemical Industries), 2,2′-azobis (isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) 5.73 g and 300 ml of toluene were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. The reaction solution was concentrated to obtain 200 g of a pale yellow liquid (yield: 95%). The reaction formula is as follows and is represented by the following chemical formula: 5-((2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) Thio) pentane-1-thiol: 5-((2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) thio) pentane-1-thiol (organosilane 1) was obtained.

  From the following NMR results, the product was identified as organosilane 1 represented by the above chemical formula.

¹ H NMR (400 MHz CDCl ₃ , δ in ppm): 1.21 (t, 9H, -Si- (O-CH ₂ -C H ₃ ) ₃ ), 3.83 (q, 6H, -Si- (OC H ₂ -CH ₃ ) ₃ ), 0.56 (t, 2H, -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 1.62 (m, 2H, -S-CH ₂ -C H ₂ -CH ₂ -Si -), 2.60 (t, 2H, -SC H ₂ -CH ₂ -CH ₂ -Si-), 1.38 (s, 6H, -C (C H ₃ ) ₂ -S-), 1.51 (m, 1H, cyclohexane C H ), 1.38-1.63 (m, 4H, cyclohexane C H ₂ ), 1.59-1.84 (m, 2H, cyclohexane C H ₂ ), 1.81 (m 1H, cyclohexane C H ), 2.38 (m 1H, cyclohexane C H ), 0.88 (s, 3H, 4-methylcyclohexane C H ₃ ), 2.60 (t, 2H, HS-CH ₂ -CH ₂ -CH ₂ -CH ₂ -C H ₂ -S-), 1.64 (m, 2H, HS-CH ₂ -CH ₂ -CH ₂ -C H ₂ -CH ₂ -S-), 1.55 (m, 2H, HS-CH ₂ -CH ₂ -C H ₂ -CH ₂ -CH ₂ -S-), 1.50 (m, 2H, HS-CH ₂ -C H ₂ -CH ₂ -CH ₂ -CH ₂ -S-), 2.53 (t, 2H, HS-C H ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -S-), 1.3 (m, 1H, H S-CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -S-).
_{^{13 C NMR (400MHz CDCl 3,}} δ in ppm): 18.4 (-Si- (O-CH 2 - C H 3) 3), 58.4 (-Si- (O- C H 2 -CH 3) 3), 15.6 ( -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 17.4 (-S-CH ₂ - C H ₂ -CH ₂ -Si-), 31.7 (-S- C H ₂ -CH ₂ -CH ₂ -Si-), 25.9 (-C ( C H ₃ ) ₂ -S-), 44.8 ( -C (CH ₃ ) ₂ -S-), 43.8 (cyclohexane C H), 24.6 (cyclohexane C H ₂ ), 30.2 (cyclohexane C H ₂ ), 32.5 (cyclohexane C H ₂ ), 37.6 (cyclohexane C H), 57.0 (cyclohexane C H), 17.4 (4-methylcyclohexane C H3), 36.7 (HS-CH ₂ -CH ₂ -CH ₂ -CH ₂ -C H ₂ -S-), 30.2 (HS-CH ₂ -CH ₂ -CH ₂ -C H ₂ -CH ₂ -S-), 28.2 (HS-CH ₂ -CH ₂ - C H ₂ -CH ₂ -CH ₂ -S-), 33.5 (HS-CH ₂ -C H ₂ -CH ₂ -CH ₂ -CH ₂ -S-), 24.6 (HS- C H ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -S-).

[Synthesis Example 2]
150 g of (3-mercaptopropyl) triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), 85.7 g of limonene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2′-azobis (isobutyronitrile) (Wako Pure Chemical Industries, Ltd.) 8.99 g of Kogyo Co., Ltd. and 300 ml of toluene were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. Thereafter, the reaction solution was concentrated to obtain 227 g of a colorless liquid (yield: 97%). For 150 g of the obtained compound, 36.9 g of thioglycolic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 5.72 g of 2,2′-azobis (isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) And 300 ml of toluene was mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. The reaction solution was concentrated to obtain 181.3 g of a pale yellow liquid (yield: 97%). The reaction formula is as follows, and 2-((2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) represented by the following chemical formula: Thio) acetic acid: 2-((2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) thio) acetic acid (organosilane 2) was obtained.

  From the following NMR results, the product was identified as organosilane 2 represented by the above chemical formula.

¹ H NMR (400 MHz CDCl ₃ , δ in ppm): 1.21 (t, 9H, -Si- (O-CH ₂ -C H ₃ ) ₃ ), 3.83 (q, 6H, -Si- (OC H ₂ -CH ₃ ) ₃ ), 0.56 (t, 2H, -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 1.62 (m, 2H, -S-CH ₂ -C H ₂ -CH ₂ -Si -), 2.60 (t, 2H, -SC H ₂ -CH ₂ -CH ₂ -Si-), 1.38 (s, 6H, -C (C H ₃ ) ₂ -S-), 1.51 (m, 1H, cyclohexane C H ), 1.38-1.63 (m, 4H, cyclohexane C H ₂ ), 1.59-1.84 (m, 2H, cyclohexane C H ₂ ), 1.81 (m 1H, cyclohexane C H ), 2.38 (m 1H, cyclohexane C H ), 0.88 (s, 3H, 4-methylcyclohexane C H ₃ ), 3.38 (t, 2H, HO-C = OC H ₂ -S-), 12.34 (s, 1H, H O-C = O-CH ₂ -S- ).
_{^{13 C NMR (400MHz CDCl 3,}} δ in ppm): 18.4 (-Si- (O-CH 2 - C H 3) 3), 58.4 (-Si- (O- C H 2 -CH 3) 3), 15.6 ( -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 17.4 (-S-CH ₂ - C H ₂ -CH ₂ -Si-), 31.7 (-S- C H ₂ -CH ₂ -CH ₂ -Si-), 25.9 (-C ( C H ₃ ) ₂ -S-), 44.8 ( -C (CH ₃ ) ₂ -S-), 43.8 (cyclohexane C H), 24.6 (cyclohexane C H ₂ ), 30.2 (cyclohexane C H ₂ ), 32.2 (cyclohexane C H ₂ ), 37.3 (cyclohexane C H), 56.4 (cyclohexane C H), 17.4 (4-methylcyclohexane C H ₃ ), 42.6 (HO-C = O- C H ₂ -S-), 174.6 (HO- C = O-CH ₂ -S-).

[Synthesis Example 3]
150 g of (3-mercaptopropyl) triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), 85.7 g of limonene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2′-azobis (isobutyronitrile) (Wako Pure Chemical Industries, Ltd.) 8.99 g of Kogyo Co., Ltd. and 300 ml of toluene were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. Thereafter, the reaction solution was concentrated to obtain 227 g of a colorless liquid (yield: 97%). 4. 150 g of the obtained compound, 30.9 g of 2-aminoethanethiol (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2′-azobis (isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) 72 g and 300 ml of toluene were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. The reaction solution was concentrated to obtain 174 g of a pale yellow liquid (yield: 96%). The reaction formula is as follows, and 2-((2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) represented by the following chemical formula: Thio) ethane-1-amine: 2-((2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) thio) ethan-1-amine 3) was obtained.

  From the following NMR results, it was identified that the product was organosilane 3 represented by the above chemical formula.

¹ H NMR (400 MHz CDCl ₃ , δ in ppm): 1.21 (t, 9H, -Si- (O-CH ₂ -C H ₃ ) ₃ ), 3.83 (q, 6H, -Si- (OC H ₂ -CH ₃ ) ₃ ), 0.56 (t, 2H, -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 1.62 (m, 2H, -S-CH ₂ -C H ₂ -CH ₂ -Si -), 2.60 (t, 2H, -SC H ₂ -CH ₂ -CH ₂ -Si-), 1.33 (s, 6H, -C (C H ₃ ) ₂ -S-), 1.51 (m, 1H, cyclohexane C H ), 1.38-1.63 (m, 4H, cyclohexane C H ₂ ), 1.59-1.84 (m, 2H, cyclohexane C H ₂ ), 1.81 (m, 1H, cyclohexane C H ), 2.38 (m, 1H, cyclohexane C H ), 0.88 (s, 3H, 4-methylcyclohexane C H ₃ ), 2.70 (t, 2H, H ₂ N-CH ₂ -C H ₂ -S-), 3.02 (s, 2H, H ₂ NC H ₂ -CH ₂ -S-), 1.50 (m, 2H, H ₂ N-CH ₂ -CH ₂ -S-).
_{^{13 C NMR (400MHz CDCl 3,}} δ in ppm): 18.4 (-Si- (O-CH 2 - C H 3) 3), 58.4 (-Si- (O- C H 2 -CH 3) 3), 15.6 ( -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 17.4 (-S-CH ₂ - C H ₂ -CH ₂ -Si-), 31.7 (-S- C H ₂ -CH ₂ -CH ₂ -Si-), 25.9 (-C ( C H ₃ ) ₂ -S-), 44.8 ( -C (CH ₃ ) ₂ -S-), 43.8 (cyclohexane C H), 24.6 (cyclohexane C H ₂ ), 30.2 (cyclohexane C H ₂ ), 32.5 (cyclohexane C H ₂ ), 37.6 (cyclohexane C H), 56.7 (cyclohexane C H), 17.4 (4-methylcyclohexane C H ₃ ), 32.8 (H ₂ N-CH ₂ -C H ₂ -S-), 38.0 (H ₂ N- C H ₂ -CH ₂ -S-).

[Synthesis Example 4]
150 g of (3-mercaptopropyl) triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), 85.7 g of limonene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2′-azobis (isobutyronitrile) (Wako Pure Chemical Industries, Ltd.) 8.99 g of Kogyo Co., Ltd. and 300 ml of toluene were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. Thereafter, the reaction solution was concentrated to obtain 227 g of a colorless liquid (yield: 97%). To 150 g of the obtained compound, 30.5 g of thioacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 5.72 g of 2,2′-azobis (isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) and toluene 300 ml was mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. The reaction solution was concentrated to obtain 175 g of a pale yellow liquid (yield: 97%). The reaction formula is as follows, and S- (2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) ethane represented by the following chemical formula Thioate: S- (2-methyl-5- (2-((3- (triethoxysilyl) propyl) thio) propan-2-yl) cyclohexyl) ethanethioate (organosilane 4) was obtained.

  From the following NMR results, the product was identified as organosilane 4 represented by the above chemical formula.

¹ H NMR (400 MHz CDCl ₃ , δ in ppm): 1.21 (t, 9H, -Si- (O-CH ₂ -C H ₃ ) ₃ ), 3.83 (q, 6H, -Si- (OC H ₂ -CH ₃ ) ₃ ), 0.56 (t, 2H, -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 1.62 (m, 2H, -S-CH ₂ -C H ₂ -CH ₂ -Si -), 2.60 (t, 2H, -SC H ₂ -CH ₂ -CH ₂ -Si-), 1.33 (s, 6H, -C (C H ₃ ) ₂ -S-), 1.51 (m, 1H, cyclohexane C H ), 1.38-1.63 (m, 4H, cyclohexane C H ₂ ), 1.88-2.13 (m, 2H, cyclohexane C H ₂ ), 1.73 (m 1H, cyclohexane C H ), 2.65 (m 1H, cyclohexane C H ), 0.88 (s, 3H, 4-methylcyclohexane C H ₃ ), 2.30 (t, 3H, H ₃ CC = OS-).
_{^{13 C NMR (400MHz CDCl 3,}} δ in ppm): 18.4 (-Si- (O-CH 2 - C H 3) 3), 58.4 (-Si- (O- C H 2 -CH 3) 3), 15.6 ( -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 17.4 (-S-CH ₂ - C H ₂ -CH ₂ -Si-), 31.7 (-S- C H ₂ -CH ₂ -CH ₂ -Si-), 25.9 (-C ( C H ₃ ) ₂ -S-), 45.2 ( -C (CH ₃ ) ₂ -S-), 44.0 (cyclohexane C H), 25.0 (cyclohexane C H ₂ ), 30.1 (cyclohexane C H ₂ ), 30.4 (cyclohexane C H ₂ ), 35.2 (cyclohexane C H), 39.5 (cyclohexane C H), 17.6 (4-methylcyclohexane C H ₃ ), 194.9 (H ₃ C- C = OS-), 30.8 (H ₃ C -C = OS-).

[Synthesis Example 5]
150 g of (3-mercaptopropyl) triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), 68.1 g of 4-vinyl-1-cyclohexene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2′-azobis (isobutyro) Nitrile) (Wako Pure Chemical Industries, Ltd.) 9.00 g and toluene 300 ml were mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. Thereafter, the reaction solution was concentrated to obtain 209 g of a colorless liquid (yield: 96%). To 150 g of the obtained compound, 33.0 g of thioacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 6.19 g of 2,2′-azobis (isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) and toluene 300 ml was mixed in an eggplant flask, bubbled with nitrogen gas for 30 minutes, and reacted at 70 ° C. for 6 hours. The reaction solution was concentrated to obtain 179 g of a pale yellow liquid (yield: 98%). The reaction formula is S- (3- (2-((3- (triethoxysilyl) propyl) thio) ethyl) cyclohexyl) ethanethioate represented by the following chemical formula: S- (3- ( 2-((3- (triethoxysilyl) propyl) thio) ethyl) cyclohexyl) ethanethioate (organosilane 5-1) and S- (4- (2-((3- (triethoxysilyl) propyl) thio) ethyl) cyclohexyl Ethanethioate: S- (4- (2-((3- (triethoxysilyl) propyl) thio) ethyl) cyclohexyl) Organosilane 5 consisting of a mixture with ethanethioate (organosilane 5-2) was obtained.

  From the following NMR results, it was identified that the product was organosilane 5 represented by the above chemical formula.

Organosilane 5-1
¹ H NMR (400 MHz CDCl ₃ , δ in ppm): 1.21 (t, 9H, -Si- (O-CH ₂ -C H ₃ ) ₃ ), 3.83 (q, 6H, -Si- (OC H ₂ -CH ₃ ) ₃ ), 0.56 (t, 2H, -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 1.62 (m, 2H, -S-CH ₂ -C H ₂ -CH ₂ -Si -), 2.42 (m, 2H, -SC H ₂ -CH ₂ -CH ₂ -Si-), 2.60 (m, 2H, -CH ₂ -C H ₂ -S-), 1.58 (m, 2H, -C H ₂ -CH ₂ -S-), 1.50 (m, 1H, cyclohexane C H ), 1.38-1.63 (m, 2H, cyclohexane C H ₂ ), 1.43-1.53 (m, 2H, cyclohexane C H ₂ ), 1.88 -2.13 (m, 2H, cyclohexane C H ₂ ), 1.94-2.19 (m, 2H, cyclohexane C H ₂ ), 2.75 (q 1H, cyclohexane C H ), 2.30 (s, 3H, H ₃ CC = OS-) .
_{^{13 C NMR (400MHz CDCl 3,}} δ in ppm): 18.4 (-Si- (O-CH 2 - C H 3) 3), 58.4 (-Si- (O- C H 2 -CH 3) 3), 15.6 ( -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 16.8 (-S-CH ₂ - C H ₂ -CH ₂ -Si-), 36.4 (-S- C H ₂ -CH ₂ -CH ₂ -Si-), 31.0 (-CH ₂ -C H ₂ -S-), 32.0 ( -C H ₂ -CH ₂ -S-), 32.0 (cyclohexane C H), 18.3 (cyclohexane C H ₂ ) , 31.4 (cyclohexane C H ₂ ), 32.9 (cyclohexane C H ₂ ), 38.0 (cyclohexane C H ₂ ), 43.1 (cyclohexane C H), 194.9 (H ₃ C- C = OS-), 30.8 (H ₃ C- C = OS-).

Organosilane 5-2
¹ H NMR (400 MHz CDCl ₃ , δ in ppm): 1.21 (t, 9H, -Si- (O-CH ₂ -C H ₃ ) ₃ ), 3.83 (q, 6H, -Si- (OC H ₂ -CH ₃ ) ₃ ), 0.56 (t, 2H, -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 1.62 (m, 2H, -S-CH ₂ -C H ₂ -CH ₂ -Si -), 2.42 (m, 2H, -SC H ₂ -CH ₂ -CH ₂ -Si-), 2.60 (m, 2H, -CH ₂ -C H ₂ -S-), 1.58 (m, 2H, -C H ₂ -CH ₂ -S-), 1.50 (m, 1H, cyclohexane C H ), 1.38-1.63 (m, 4H, cyclohexane C H ₂ ), 1.94-2.19 (m, 4H, cyclohexane C H ₂ ), 2.75 (q 1H, cyclohexane C H ), 2.30 (s, 3H, H ₃ CC = OS-).
_{^{13 C NMR (400MHz CDCl 3,}} δ in ppm): 18.4 (-Si- (O-CH 2 - C H 3) 3), 58.4 (-Si- (O- C H 2 -CH 3) 3), 15.6 ( -C H ₂ -Si- (O-CH ₂ -CH ₃ ) ₃ ), 16.8 (-S-CH ₂ - C H ₂ -CH ₂ -Si-), 36.4 (-S- C H ₂ -CH ₂ -CH ₂ -Si-), 31.0 (-CH ₂ - C H ₂ -S-), 32.0 ( -C H ₂ -CH ₂ -S-), 35.1 (cyclohexane C H), 30.0 (cyclohexane C H ₂ ) , 29.8 (cyclohexane C H ₂ ), 45.6 (cyclohexane C H), 194.9 (H ₃ C- C = OS-), 30.8 (H ₃ C -C = OS-).

<Evaluation of rubber composition>
Using a Banbury mixer, according to the formulation (parts by mass) shown in Table 1 below, first, in the first mixing stage, other compounding agents except for sulfur and vulcanization accelerator are added to the diene rubber component and kneaded ( (Discharge temperature = 160 ° C.) Then, sulfur and a vulcanization accelerator were added and kneaded to the obtained kneaded product in the final mixing stage (discharge temperature = 90 ° C.) to prepare a rubber composition. The details of each component in Table 1 are as follows.

・ SBR: LANXESS Corporation "VSL5025-0HM"
-Modified SSBR: amino group and alkoxy group terminal modified solution polymerized styrene butadiene rubber, "HPR350" manufactured by JSR Corporation
-BR: “BR150B” manufactured by Ube Industries, Ltd.
Silane coupling agent A: bis (3-triethoxysilylpropyl) tetrasulfide, “Si69” manufactured by Evonik Degussa
Organic silane 1: synthesized in Synthesis Example 1 Organic silane 2: synthesized in Synthesis Example 2 Organic silane 3: synthesized in Synthetic Example 3 organic silane 4: synthesized in Synthetic Example 4 Organic Silane 5: synthesized in Synthesis Example 5 ・ Silica: “Nip Seal AQ” manufactured by Tosoh Silica Co., Ltd.
Carbon black: “Dia Black N341” manufactured by Mitsubishi Chemical Corporation
-Oil: "Extract No. 4 S" manufactured by Showa Shell Sekiyu KK
・ Zinc flower: “Zinc flower No. 1” manufactured by Mitsui Mining & Smelting Co., Ltd.
Anti-aging agent: “Antigen 6C” manufactured by Sumitomo Chemical Co., Ltd.
・ Stearic acid: “Lunac S-20” manufactured by Kao Corporation
・ Wax: Nippon Seiki Co., Ltd. “OZOACE0355”
・ Sulfur: “5% oil-filled fine powder sulfur” manufactured by Tsurumi Chemical Co., Ltd.
・ Vulcanization accelerator: “Soxinol CZ” manufactured by Sumitomo Chemical Co., Ltd.

  About each obtained rubber composition, while scorching-proof performance was evaluated, the test piece of a predetermined shape was produced by vulcanizing | curing at 160 degreeC x 20 minutes, and low-fuel-consumption performance and wet grip performance were evaluated. Each evaluation method is as follows.

・ Scorch resistance performance: After preheating the unvulcanized rubber composition at 125 ° C for 1 minute using a Toyo Seiki Co., Ltd. rotorless Mooney measuring machine in accordance with JIS K6300, the Mooney unit increases by 5 Mooney units from the minimum viscosity Vm. The time t5 required for the measurement was measured and indicated by an index with the value of Comparative Example 3 taken as 100. A larger index means longer scorch time and better scorch resistance.

-Low fuel consumption performance (heat generation characteristics): Using a viscoelasticity tester manufactured by Toyo Seiki Co., Ltd., the loss factor tanδ is measured under conditions of initial strain 10%, dynamic strain 1%, frequency 10 Hz, and temperature 60 ° C. Indicated by an index with the value of Comparative Example 3 as 100. Tan δ at 60 ° C. is generally used as an index of low fuel consumption performance in rubber compositions for tires. The smaller the index, the smaller the tan δ, and thus less heat generation, resulting in low fuel consumption performance as a tire. Shows superiority.

-Wet grip performance (low temperature characteristics): tan δ was measured in the same manner as the low fuel consumption performance except that the measurement temperature was changed to 0 ° C. Tan δ at 0 ° C. is generally used as an index of wet grip performance in a rubber composition for tires, and the larger the index, the larger tan δ and the better wet grip performance.

  The results are as shown in Table 1. As shown in Examples 1 to 7, when the organic silanes 1 to 5 according to Synthesis Examples 1 to 5 were blended as silane coupling agents, with respect to Comparative Examples 2 to 4 blended with polysulfide silane, the same blending amount was used. In comparison, fuel economy performance and wet grip performance were improved in a well-balanced manner, and scorch resistance was also good. In addition, as shown in Example 11, when organosilane 2 having a functional group that interacted with the functional group was used together with the modified SSBR, further improvement effects in fuel efficiency and wet grip performance were observed.

Claims (5)

Rubber obtained by blending 100 parts by mass of diene rubber, 20 to 150 parts by mass of silica, and 2 to 20% by mass of organic silane represented by the following general formula (1) and / or (2) with respect to the mass of silica. Composition.

(In the formula, X ¹ , X ² and X ³ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. One of A ¹ and A ² is —C _x H _2x —SiR ¹ R. ² R ³ and the other is —C _m H _n —Z or —C (═O) —R ^4. R ¹ , R ² and R ³ are each an alkyl group or alkoxy group having 1 to 3 carbon atoms. And at least one is an alkoxy group, x is an integer of 2 to 4, m is an integer of 1 to 22, and n is an integer of 2 to 44. Z is a mercapto group, a carboxyl group, or a hydroxyl group. Or R ⁴ is an aliphatic or aromatic hydrocarbon group having 1 to 18 carbon atoms, —SA ² is bonded to the 3rd or 4th carbon atom of the cyclohexyl group, and 3 It may be a mixture of those bonded to the position and those bonded to the 4-position.) The general formulas (1) and (2), wherein X ¹ is an alkyl group having 1 to 3 carbon atoms, and —SA ² is bonded to the carbon atom at the 3-position of the cyclohexyl group. The rubber composition according to 1. In the general formulas (1) and (2), X ¹ is a hydrogen atom, -SA ² is bonded to the 3rd or 4th carbon atom of the cyclohexyl group, and is bonded to the 3rd position. 2. The rubber composition according to claim 1, which is a mixture of those bonded at the 4-position.   In the general formulas (1) and (2), Z is a carboxyl group, a hydroxyl group or an amino group, and the diene rubber is selected from the group consisting of an alkoxy group, a carbonyl group, a hydroxyl group, an amino group and an epoxy group. The rubber composition according to any one of claims 1 to 3, comprising a modified diene rubber in which at least one functional group is introduced into a molecular terminal or a molecular chain.   The pneumatic tire which uses the rubber composition of any one of Claims 1-4.