JP5508037B2 - Rubber composition for tire and studless tire - Google Patents

Description

The present invention relates to a rubber composition for tires and a studless tire using the same.

Spike tires have been used for running on snowy and snowy roads, and chains have been attached to tires. However, environmental problems such as dust problems have occurred, and studless tires have been developed as snowy and snowy road running tires. Since it is used on an icy and snowy road surface where the frictional force is lower than that of a general road surface, the studless tire is devised in terms of material and design. For example, a rubber composition containing a diene rubber excellent in low temperature characteristics has been developed. However, the grip performance on snowy and snowy road surfaces of studless tires is not sufficient, and further improvement in performance is required.

In order to improve the grip performance on snowy and snowy road surfaces, it has been studied to add various additives (for example, eggshell powder) to the rubber composition. However, blending additives improves the grip performance on icy and snowy road surfaces, but there is a problem that wear resistance decreases.

Patent Document 1 discloses that by incorporating a silane coupling agent having a mercapto group, processability, workability, and low fuel consumption can be improved. However, there is room for improvement in terms of performance on ice (grip performance on the road surface on ice) and wear resistance.

JP 2009-126907 A

The present invention solves the above-mentioned problems, and improves the performance on ice (grip performance on the road surface on ice) and the wear resistance in a well-balanced manner, and the tire rubber composition is used for each member of the tire (particularly, The object is to provide a studless tire used for tread.

（式（１）中、Ｒ^１は−Ｏ−（Ｒ^５−Ｏ）_ｍ−Ｒ^６（ｍ個のＲ^５は、同一又は異なって、分岐若しくは非分岐の炭素数１〜３０の２価の炭化水素基を表す。Ｒ^６は、分岐若しくは非分岐の炭素数１〜３０のアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基、炭素数６〜３０のアリール基又は炭素数７〜３０のアラルキル基を表す。ｍは１〜３０の整数を表す。）で表される基を表す。Ｒ^２及びＲ^３は、同一若しくは異なって、Ｒ^１と同一の基、分岐若しくは非分岐の炭素数１〜１２のアルキル基又は−Ｏ−Ｒ^７（Ｒ^７は水素原子、分岐若しくは非分岐の炭素数１〜３０のアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基、炭素数６〜３０のアリール基又は炭素数７〜３０のアラルキル基を表す。）で表される基を表す。Ｒ^４は、分岐若しくは非分岐の炭素数１〜３０のアルキレン基を表す。）

（式（２）、（３）中、ｘは０以上の整数である。ｙは１以上の整数である。Ｒ^８は水素、ハロゲン、分岐若しくは非分岐の炭素数１〜３０のアルキル基若しくはアルキレン基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基若しくはアルケニレン基、分岐若しくは非分岐の炭素数２〜３０のアルキニル基若しくはアルキニレン基、又は該アルキル基若しくは該アルケニル基の末端が水酸基若しくはカルボキシル基で置換されたものを示す。Ｒ^９は水素、分岐若しくは非分岐の炭素数１〜３０のアルキレン基若しくはアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニレン基若しくはアルケニル基、又は分岐若しくは非分岐の炭素数２〜３０のアルキニレン基若しくはアルキニル基を示す。Ｒ^８とＲ^９とで環構造を形成してもよい。） The present invention includes a rubber component containing 15% by mass or more of isoprene-based rubber, silica, a silane coupling agent represented by the following formula (1) and / or a binding unit A represented by the following formula (2) and the following formula: It is related with the rubber composition for tires containing the silane coupling agent which consists of the bond unit B shown by (3).

(In Formula (1), R ¹ is —O— (R ⁵ —O) _m —R ^{6, where} m R ^{5 s} are the same or different and are branched or unbranched C 1-30 divalent. R ⁶ represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or 7 carbon atoms. Represents an aralkyl group of -30. M represents an integer of 1-30.) R ² and R ³ are the same or different and are the same group as R ¹ , branched or unbranched. An alkyl group having 1 to 12 carbon atoms or —O—R ⁷ (R ⁷ is a hydrogen atom, a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, An aryl group having 6 to 30 carbon atoms or an aralkyl group having 7 to 30 carbon atoms is represented. .R ⁴ representing a group represented by in represents a branched or unbranched alkylene group having 1 to 30 carbon atoms.)

(In the formulas (2) and (3), x is an integer greater than or equal to 0. y is an integer greater than or equal to 1. R ⁸ is hydrogen, halogen, a branched or unbranched C1-C30 alkyl group or An alkylene group, a branched or unbranched alkenyl group or alkenylene group having 2 to 30 carbon atoms, a branched or unbranched alkynyl group or alkynylene group having 2 to 30 carbon atoms, or a terminal of the alkyl group or alkenyl group is a hydroxyl group or R ⁹ is substituted with a carboxyl group, R ⁹ is hydrogen, branched or unbranched alkylene group or alkyl group having 1 to 30 carbon atoms, branched or unbranched C 2-30 alkenylene group or alkenyl group, or A branched or unbranched alkynylene group or alkynyl group having 2 to 30 carbon atoms, wherein R ⁸ and R ⁹ form a ring structure. May be.)

The tire rubber composition preferably includes eggshell powder having an average particle size of 10 to 150 μm.

The silica preferably has a nitrogen adsorption specific surface area of 40 to 250 m ² / g.

The tire rubber composition is preferably used as a tread rubber composition.

The present invention also relates to a studless tire produced using the rubber composition.

According to the present invention, a rubber component containing a specific amount or more of isoprene-based rubber, silica, a silane coupling agent represented by the above formula (1) and / or a binding unit A represented by the above formula (2) and the above Since it is a rubber composition for tires containing the silane coupling agent which consists of the bond unit B shown by Formula (3), performance on ice is obtained by using this rubber composition for each member (especially tread) of a tire. It is possible to provide a studless tire that can improve (grip performance on the road surface on ice) and wear resistance in a well-balanced manner.

The rubber composition for tires of the present invention includes a rubber component containing a specific amount or more of isoprene-based rubber, silica, a silane coupling agent represented by the above formula (1) and / or a bond represented by the above formula (2). A unit A and a silane coupling agent composed of a binding unit B represented by the above formula (3).

In the present invention, isoprene-based rubber is included as a rubber component. By blending isoprene-based rubber, the performance on ice (grip performance on the road surface on ice) and wear resistance can be improved in a balanced manner.
Rubber compositions containing isoprene-based rubber (for example, natural rubber) and butadiene rubber tend to have long scorch times and low productivity. On the other hand, the silane coupling agent represented by the above formula (1) and / or the silane coupling agent comprising the binding unit A represented by the above formula (2) and the coupling unit B represented by the above formula (3) is a mercapto. Since it is a silane coupling agent having a group, scorch tends to occur (the scorch time becomes too short).
In the present invention, a specific amount or more of isoprene-based rubber, a silane coupling agent represented by the above formula (1) and / or a bond unit A represented by the above formula (2) and a bond represented by the above formula (3). By using together with the silane coupling agent consisting of the unit B, the scorch time can be adjusted to an appropriate range, and the processability and productivity are excellent. Furthermore, productivity can be improved despite the inclusion of isoprene-based rubber. Moreover, compared with the case where the generation of scorch by the silane coupling agent is prevented by increasing the amount of zinc oxide (the technique described in Patent Document 1), the wear resistance can be improved.

Examples of the isoprene-based rubber include isoprene rubber (IR), natural rubber (NR), and modified natural rubber. NR includes deproteinized natural rubber (DPNR) and high-purity natural rubber (HPNR). Modified natural rubber includes epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Etc. Moreover, as NR, what is common in tire industry, such as SIR20, RSS # 3, TSR20, can be used, for example. Moreover, as IR, what is common in the tire industry can be used. These may be used alone or in combination of two or more.

100% by mass of the rubber component contains 15% by mass or more of isoprene-based rubber, preferably 20% by mass or more, more preferably 25% by mass or more, and further preferably 30% by mass or more. If it is less than 15% by mass, the reinforcing effect as rubber may not be sufficiently obtained. Further, the content of the isoprene-based rubber is preferably 70% by mass or less, more preferably 60% by mass or less. If it exceeds 70% by mass, the low-temperature characteristics (such as performance on ice) important for studless tires may be inferior.

The rubber component that can be used in the present invention other than isoprene-based rubber is not particularly limited, but is butadiene rubber (BR), styrene butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), styrene isoprene butadiene rubber. Examples thereof include diene rubbers such as (SIBR), styrene isoprene rubber (SIR), isoprene butadiene rubber, and butyl rubber (IIR). Diene rubbers may be used alone or in combination of two or more. Among these, BR is preferable because it can improve the performance on ice (grip performance on the road surface on ice) and wear resistance in a well-balanced manner, and can extend the scorch time as is the case with the isoprene-based rubber. By using isoprene-based rubber and BR together, the scorch time can be further adjusted to an appropriate range.

The BR is not particularly limited. For example, BR1220 manufactured by Nippon Zeon Co., Ltd., BR130B manufactured by Ube Industries, Ltd., BR150B having a high cis content such as BR150B, VCR412 manufactured by Ube Industries, Ltd. BR containing syndiotactic polybutadiene crystals can be used. Among them, the BR cis content is preferably 80% by mass or more because the abrasion resistance can be further improved.

The content of BR in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more. If it is less than 30% by mass, the low temperature characteristics (such as performance on ice) important for studless tires may be inferior. The BR content is preferably 80% by mass or less, more preferably 70% by mass or less. When it exceeds 80 mass%, workability may be deteriorated.

The total content of isoprene-based rubber and BR in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 80% by mass or more, and particularly preferably 100% by mass. . If it is less than 30% by mass, a sufficient reinforcing effect as rubber may not be obtained. Moreover, there is a possibility that the performance on ice (grip performance on the road surface on ice) and the wear resistance cannot be improved in a balanced manner. Further, the scorch time cannot be adjusted to an appropriate range, and the processability and productivity tend to be inferior.

In the present invention, silica is used. By blending silica, good on-ice performance (grip performance on the road surface on ice) and high rubber strength (wear resistance) can be obtained. The silica is not particularly limited, and examples thereof include dry process silica (anhydrous silicic acid), wet process silica (hydrous silicic acid), and the like, but wet process silica is preferable because of its large number of silanol groups.

The nitrogen adsorption specific surface area _(N 2 SA) of silica is preferably not less than ^{40 m} 2 / g, more preferably at least ^{50m 2 / g, 100m 2 /} g or more, and particularly preferably equal to or greater than 150m ² / g. If it is less than 40 m < ² > / g, there exists a tendency for the fracture strength (wear resistance) after a vulcanization to fall. The _N 2 SA of the silica is preferably 250 meters ² / g or less, more preferably 220 m ² / g or less, 200 meters ² / g or less is more preferable. When it exceeds 250 m ² / g, there is a tendency that low heat build-up and rubber processability are lowered.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

The content of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, and particularly preferably 30 parts by mass or more with respect to 100 parts by mass of the rubber component. When the amount is less than 10 parts by mass, there is a tendency that a sufficient effect due to silica blending cannot be obtained. The content of the silica is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, still more preferably 80 parts by mass or less, and particularly preferably 60 parts by mass or less. When the amount exceeds 150 parts by mass, it is difficult to disperse silica in rubber, and the processability of rubber tends to deteriorate.

In the present invention, a silane coupling agent comprising a silane coupling agent represented by the following formula (1) and / or a binding unit A represented by the following formula (2) and a binding unit B represented by the following formula (3) ( The bond unit B is an essential unit, and the bond unit A is an arbitrary unit.

By blending the silane coupling agent represented by the following formula (1), the performance on ice (grip performance on the road surface on ice) and the wear resistance can be improved (coexisting) in a balanced manner.

R ^{1 in the} above formula (1) is —O— (R ⁵ —O) _m —R ⁶ (m R ^{5 s} are the same or different and are branched or unbranched divalent carbon atoms having 1 to 30 carbon atoms. R ⁶ represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or 7 to 7 carbon atoms. Represents an aralkyl group of 30. m represents an integer of 1 to 30).

R ⁵ is the same or different and represents a branched or unbranched divalent hydrocarbon group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms).
Examples of the hydrocarbon group include a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, and a branched or unbranched alkynylene group having 2 to 30 carbon atoms. And an arylene group having 6 to 30 carbon atoms. Among these, the alkylene group is preferable because it easily bonds (reacts) with silica and can sufficiently improve the performance on ice.

Examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms) of R ⁵ include, for example, a methylene group, an ethylene group, a propylene group, and a butylene group. Pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group and the like.

Branched or unbranched carbon atoms 2 to 30 of R ⁵ as the alkenylene group (preferably having from 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms), for example, vinylene group, propenylene group, 2-propenylene Group, 1-butenylene group, 2-butenylene group, 1-pentenylene group, 2-pentenylene group, 1-hexenylene group, 2-hexenylene group, 1-octenylene group and the like.

Examples of the branched or unbranched alkynylene group having 2 to 30 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms) for R ⁵ include, for example, an ethynylene group, a propynylene group, a butynylene group, and a pentynylene group. Hexynylene group, heptynylene group, octynylene group, noninylene group, decynylene group, undecynylene group, dodecynylene group and the like.

Examples of the arylene group having 6 to 30 carbon atoms (preferably 6 to 15 carbon atoms) of R ⁵ include a phenylene group, a tolylene group, a xylylene group, and a naphthylene group.

The m represents an integer of 1 to 30 (preferably 3 to 7, more preferably 5 to 6). When m is 0, the bond (reaction) with silica is disadvantageous, and when m is 31 or more, the reactivity with silica is lowered, which is disadvantageous in terms of process.

R ⁶ represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. Represent. Among these, a branched or unbranched alkyl group having 1 to 30 carbon atoms is preferable because of its good reactivity with silica.

Examples of the branched or unbranched alkyl group having 1 to 30 carbon atoms (preferably 3 to 25 carbon atoms, more preferably 10 to 15 carbon atoms) of R ⁶ include, for example, a methyl group, an ethyl group, an n-propyl group, Isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group and the like.

Examples of the branched or unbranched alkenyl group having 2 to 30 carbon atoms (preferably 2 to 30 carbon atoms, more preferably 10 to 15 carbon atoms) for R ⁶ include, for example, vinyl group, 1-propenyl group, 2-propenyl group. Group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 2-pentenyl group, 1-hexenyl group, 2-hexenyl group, 1-octenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group Group, pentadecenyl group, octadecenyl group and the like.

Examples of the aryl group having 6 to 30 carbon atoms (preferably 6 to 15 carbon atoms) of R ⁶ include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group.

Examples of the aralkyl group having 7 to 30 carbon atoms (preferably 7 to 20 carbon atoms) of R ⁶ include a benzyl group and a phenethyl group.

Specific examples of R ^{1 in} the above formula (1) include, for example, —O— (C ₂ H ₄ —O) ₅ —C ₁₁ H ₂₃ , —O— (C ₂ H ₄ —O) ₅ —C ₁₂ H. _{25, -O- (C 2 H 4} -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) 5 -C 14 H 29, -O- (C 2 H 4 -O) 5 _{-C 15 H 31, -O- (C} 2 H 4 -O) 3 -C 13 H 27, -O- (C 2 H 4 -O) 4 -C 13 H 27, -O- (C 2 H 4 _{-O) 6 -C 13 H 27,} -O- (C 2 H 4 -O) 7 -C 13 H 27 and the like. Among _{these, -O- (C 2 H 4 -O} ) 5 -C 11 H 23, -O- (C 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) _{5 -C 15 H 31, -O- (} C 2 H 4 -O) 6 -C 13 H 27 are preferable.

R ² and R ³ are the same or different and are the same group as R ¹ (that is, a group represented by —O— (R ⁵ —O) _m —R ⁶ ), branched or unbranched carbon atoms of 1 to 12 alkyl groups or —O—R ⁷ (R ⁷ is a hydrogen atom, a branched or unbranched C 1-30 alkyl group, a branched or unbranched C 2-30 alkenyl group, a C 6-30 carbon atom; An aryl group or an aralkyl group having 7 to 30 carbon atoms). Among them, the group represented by the same group as R ¹ , —O—R ⁷ (when R ⁷ is a branched or unbranched alkyl group having 1 to 30 carbon atoms) is preferable because of its good reactivity with silica. Preferred are the groups

Examples of the branched or unbranched alkyl group having 1 to 12 carbon atoms (preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms) of R ² and R ³ include, for example, a methyl group, an ethyl group, and n- Examples include propyl group, isopropyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, and nonyl group. It is done.

Branched or unbranched having 1 to 30 carbon atoms of R ⁷ as a (preferably having 1 to 15 carbon atoms, more preferably having 1 to 3 carbon atoms) alkyl group, for example, the number of carbon atoms of branched or unbranched the ^{R 6} The group similar to the alkyl group of 1-30 can be mentioned.

Branched or unbranched carbon atoms 2 to 30 R ⁷ The alkenyl group (preferably having from 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms), for example, the number of carbon atoms of branched or unbranched the ^{R 6} The group similar to a 2-30 alkenyl group can be mentioned.

Examples of the aryl group having 6 to 30 carbon atoms (preferably 6 to 15 carbon atoms) of R ⁷ include the same groups as the aryl group having 6 to 30 carbon atoms of R ⁶ .

Examples of the aralkyl group having 7 to 30 carbon atoms (preferably 7 to 15 carbon atoms) of R ⁷ include the same groups as the aralkyl group having 7 to 30 carbon atoms of R ⁶ .

Specific examples of R ² and R ^{3 in} the above formula (1) include, for example, —O— (C ₂ H ₄ —O) ₅ —C ₁₁ H ₂₃ , —O— (C ₂ H ₄ —O) ₅ —. _{C 12 H 25, -O- (C} 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) 5 -C 14 H 29, -O- (C 2 H 4 - _{O) 5 -C 15 H 31,} -O- (C 2 H 4 -O) 3 -C 13 H 27, -O- (C 2 H 4 -O) 4 -C 13 H 27, -O- (C _{2 H 4 -O) 6 -C 13} H 27, -O- (C 2 H 4 -O) 7 -C 13 H 27, C 2 H 5 -O-, CH 3 -O-, C 3 H 7 - O- and the like. Among _{these, -O- (C 2 H 4 -O} ) 5 -C 11 H 23, -O- (C 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) _{5 -C 15 H 31, -O- (} C 2 H 4 -O) 6 -C 13 H 27, C 2 H 5 -O- are preferable.

Branched or unbranched having 1 to 30 carbon atoms of R ⁴ as the alkylene group (preferably having from 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms), for example, the number of carbon atoms of branched or unbranched the ^{R 5} The same group as the alkylene group of 1-30 can be mentioned.

As the silane coupling agent represented by the above formula (1), for example, Si363 manufactured by Evonik Degussa can be used. These may be used alone or in combination of two or more.

By blending a silane coupling agent consisting of a bond unit B represented by the following formula (3) and a bond unit A represented by the following formula (2) as required, bis (3-triethoxysilylpropyl) tetra Compared with conventional silane coupling agents such as sulfide, the balance between performance on ice and rubber strength (abrasion resistance) can be improved.

The silane coupling agent composed of the binding unit A and the binding unit B is preferably a copolymer obtained by copolymerizing the binding unit B at a ratio of 1 to 70 mol% with respect to the total amount of the binding unit A and the binding unit B.

When the molar ratio of the bond unit A and the bond unit B satisfies the above conditions, an increase in viscosity during processing is suppressed as compared with polysulfide silanes such as bis- (3-triethoxysilylpropyl) tetrasulfide. This is presumably because the increase in Mooney viscosity is small because the sulfide portion of the bond unit A is a C—S—C bond and is thermally stable compared to tetrasulfide and disulfide.

Moreover, when the molar ratio of the bond unit A and the bond unit B satisfies the above conditions, the shortening of the scorch time is suppressed as compared with mercaptosilane such as 3-mercaptopropyltrimethoxysilane. This is because the bond unit B has a structure of mercaptosilane, but the —C ₇ H ₁₅ portion of the bond unit A covers the —SH group of the bond unit B, so that it does not easily react with the polymer and scorch is less likely to occur. Conceivable.

（式（２）、（３）中、ｘは０以上の整数である。ｙは１以上の整数である。Ｒ^８は水素、ハロゲン、分岐若しくは非分岐の炭素数１〜３０のアルキル基若しくはアルキレン基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基若しくはアルケニレン基、分岐若しくは非分岐の炭素数２〜３０のアルキニル基若しくはアルキニレン基、又は該アルキル基若しくは該アルケニル基の末端が水酸基若しくはカルボキシル基で置換されたものを示す。Ｒ^９は水素、分岐若しくは非分岐の炭素数１〜３０のアルキレン基若しくはアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニレン基若しくはアルケニル基、又は分岐若しくは非分岐の炭素数２〜３０のアルキニレン基若しくはアルキニル基を示す。Ｒ^８とＲ^９とで環構造を形成してもよい。）

(In the formulas (2) and (3), x is an integer greater than or equal to 0. y is an integer greater than or equal to 1. R ⁸ is hydrogen, halogen, a branched or unbranched C1-C30 alkyl group or An alkylene group, a branched or unbranched alkenyl group or alkenylene group having 2 to 30 carbon atoms, a branched or unbranched alkynyl group or alkynylene group having 2 to 30 carbon atoms, or a terminal of the alkyl group or alkenyl group is a hydroxyl group or R ⁹ is substituted with a carboxyl group, R ⁹ is hydrogen, branched or unbranched alkylene group or alkyl group having 1 to 30 carbon atoms, branched or unbranched C 2-30 alkenylene group or alkenyl group, or A branched or unbranched alkynylene group or alkynyl group having 2 to 30 carbon atoms, wherein R ⁸ and R ⁹ form a ring structure. May be.)

Examples of the halogen for R ⁸ include chlorine, bromine, and fluorine.

Examples of the branched or unbranched alkyl group having 1 to 30 carbon atoms (preferably having 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms) of R ⁸ and R ⁹ include, for example, the above branched or unbranched groups of R ^6. The same group as the C1-C30 alkyl group of can be mentioned.

Examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms (preferably 1 to 12 carbon atoms) of R ⁸ and R ⁹ include, for example, the branched or unbranched alkylene group having 1 to 30 carbon atoms of R ^5. The same group can be mentioned.

Examples of the branched or unbranched alkenyl group having 2 to 30 carbon atoms (preferably 2 to 12 carbon atoms) of R ⁸ and R ⁹ include, for example, the branched or unbranched alkenyl group having 2 to 30 carbon atoms of R ^6. The same group can be mentioned.

R ^8, Examples of branched or unbranched alkenylene group having 2 to 30 carbon atoms (preferably having from 2 to 12 carbon atoms) of ^{R 9,} for example, a branched or unbranched alkenylene group having 2 to 30 carbon atoms of the ^{R 5} The same group can be mentioned.

Examples of the branched or unbranched alkynyl group having 2 to 30 carbon atoms (preferably 2 to 12 carbon atoms) of R ⁸ and R ⁹ include, for example, ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, and heptynyl. Group, octynyl group, noninyl group, decynyl group, undecynyl group, dodecynyl group and the like.

Examples of the branched or unbranched alkynylene group having 2 to 30 carbon atoms (preferably 2 to 12 carbon atoms) of R ⁸ and R ⁹ include, for example, the branched or unbranched alkynylene group having 2 to 30 carbon atoms of R ^5. The same group can be mentioned.

In the silane coupling agent comprising the binding unit A and the binding unit B, the total number of repetitions (x + y) of the repeating number (x) of the bonding unit A and the repeating number (y) of the bonding unit B is in the range of 3 to 300. Is preferred. Within this range and when x is 1 or more, since the mercaptosilane of the bond unit B is covered by —C ₇ H ₁₅ of the bond unit A, it is possible to suppress the scorch time from being shortened, and to use silica and rubber components And good reactivity can be ensured.

For example, NXT-Z30, NXT-Z45, NXT-Z60, or NXT-Z100 manufactured by Momentive can be used as the silane coupling agent composed of the binding unit A and the binding unit B. These may be used alone or in combination of two or more.

The content of the silane coupling agent represented by the above formula (1) and / or the coupling unit A represented by the above formula (2) and the coupling unit B represented by the above formula (3) is: Preferably it is 1 mass part or more with respect to 100 mass parts of silica, More preferably, it is 5 mass parts or more, More preferably, it is 8 mass parts or more. If it is less than 1 part by mass, the fracture strength tends to be greatly reduced. Moreover, this content is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of silica. When it exceeds 15 parts by mass, there is a tendency that effects such as improvement in breaking strength (wear resistance) and reduction in rolling resistance due to the incorporation of the silane coupling agent cannot be obtained sufficiently.
The content is a combination of a silane coupling agent represented by the above formula (1) and a silane coupling agent composed of the binding unit A represented by the above formula (2) and the coupling unit B represented by the above formula (3). When doing, it means the total content.

In the present invention, eggshell powder is preferably blended. Eggshell powder (for example, chicken egg powder) becomes waste as it is, and therefore, it can be considered environmentally by using this. Moreover, the performance on ice can be greatly improved by blending eggshell powder. In addition, it can be supplied in large quantities and is available at low cost. Moreover, in this invention, the silane coupling agent which consists of the coupling | bonding unit A shown by the silane coupling agent represented by the said Formula (1) and / or the said Formula (2), and the said Formula (3). The rubber component and eggshell powder are strongly bonded compared to the case where silane coupling agents such as bis (3-triethoxysilylpropyl) tetrasulfide are used in the rubber industry. And the wear resistance can be improved.

The eggshell powder is blended with the rubber component, so that (A) the eggshell powder itself scratches the ice and snow road surface, and (B) the pores present in the eggshell powder particles absorb and remove the water on the ice and snow road surface. (C) The effect of (C) the pores formed by dropping eggshell powder particles absorbing and removing the water on the ice and snow road surface, and (D) the ridges of the pores formed by dropping eggshell powder particles are edges The effect of scratching the snowy road surface is obtained. As described above, the improvement of the performance on ice is caused by the effect of removing moisture by the pores obtained by dropping off the pores existing in the eggshell powder particles or the eggshell powder particles together with the scratching effect.

The average particle diameter of the eggshell powder is preferably 10 μm or more, more preferably 12 μm or more. If the thickness is less than 10 μm, the pores produced by dropping the eggshell powder from the rubber are small, and a sufficient water absorption effect may not be obtained. The average particle diameter of the eggshell powder is preferably 150 μm or less, more preferably 120 μm or less, still more preferably 80 μm or less, particularly preferably 50 μm or less, and most preferably 30 μm or less. When it exceeds 150 μm, the fracture strength is lowered and the wear resistance may be lowered. In addition, the average particle diameter of eggshell powder is measured using a particle size distribution measuring device.

When the rubber composition of the present invention contains eggshell powder, the content of eggshell powder is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 1 part by mass, the rubber surface cannot be roughened, and sufficient on-ice performance (grip performance on an on-ice road surface) may not be obtained. Further, the content of the eggshell powder is preferably 20 parts by mass or less, more preferably 15 parts by mass or less. If it exceeds 20 parts by mass, it will fall off from the tire surface as a mere additive, which may reduce the wear resistance.

In the present invention, carbon black may be blended. Thereby, the strength (abrasion resistance) of the rubber can be improved. Examples of carbon black that can be used include GPF, FEF, HAF, ISAF, and SAF, but are not particularly limited. Carbon black may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 30 m ² / g or more, more preferably 70 m ² / g or more, and still more preferably 100 m ² / g or more. If it is less than 30 m ² / g, there is a tendency that sufficient reinforcing properties cannot be obtained. Further, the nitrogen adsorption specific surface area of the carbon black is preferably 250 meters ² / g or less, more preferably ^{150m 2 / g, 125m 2 /} g or less is more preferable. If it exceeds 250 m ² / g, the viscosity at the time of unvulcanization becomes very high, and the workability tends to deteriorate, or the fuel efficiency tends to deteriorate.
In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required by A method of JISK6217.

When the rubber composition of the present invention contains carbon black, the carbon black content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 20 parts by mass with respect to 100 parts by mass of the rubber component. More than a part. If the amount is less than 5 parts by mass, sufficient reinforcing properties tend not to be obtained. Further, the carbon black content is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 40 parts by mass or less. If it exceeds 60 parts by mass, heat generation will increase and fuel economy tends to deteriorate.

In addition to the above components, the rubber composition of the present invention includes compounding agents generally used in the production of rubber compositions, such as reinforcing fillers such as clay, zinc oxide, stearic acid, various anti-aging agents, oils A softener such as wax, a vulcanizing agent such as wax and sulfur, a vulcanization accelerator, and the like can be appropriately blended.

As a method for producing the rubber composition of the present invention, a known method can be used. For example, the above components are kneaded using a rubber kneader such as an open roll or a Banbury mixer, and then vulcanized. Can be manufactured.

The rubber composition of the present invention can be suitably used for each member (particularly tread) of a tire.

The tread may have a multilayer structure or a single layer structure.
A tread having a multilayer structure is produced by pasting a sheet into a predetermined shape, or by inserting it into two or more extruders and forming it into two or more layers at the head outlet of the extruder. Can do.

The studless tire of this invention is manufactured by a normal method using the said rubber composition. That is, if necessary, a rubber composition containing various additives is extruded in accordance with the shape of each member (particularly, tread) of the tire at an unvulcanized stage, and a normal method is performed on a tire molding machine. After being formed by bonding together with other tire members to form an unvulcanized tire, the tire can be manufactured by heating and pressing in a vulcanizer.

Moreover, the tire of the present invention is suitably used as a studless tire for passenger cars, a studless tire for buses, a studless tire for trucks, and the like.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

シランカップリング剤（３）：Ｍｏｍｅｎｔｉｖｅ社製のＮＸＴ−Ｚ１００（結合単位Ｂのみからなる重合体（（上記式（２）、（３）において、結合単位Ａ：０モル％（ｘ＝０）、結合単位Ｂ：１００モル％、ｘ＋ｙ：１００）
卵殻粉：キューピー（株）製の鶏卵殻粉（平均粒子径１５μｍ）
酸化亜鉛：三井金属鉱業（株）製の亜鉛華１号
ステアリン酸：日油（株）製のステアリン酸「椿」
老化防止剤：住友化学（株）製のアンチゲン６Ｃ（Ｎ−（１，３−ジメチルブチル）−Ｎ’−フェニル−ｐ−フェニレンジアミン）
ワックス：大内新興化学工業（株）製のサンノックＮ
アロマオイル：（株）ジャパンエナジー製のプロセスＸ−１４０
硫黄：軽井沢硫黄（株）製の粉末硫黄
加硫促進剤（１）：大内新興化学工業（株）製のノクセラーＣＺ（Ｎ−シクロヘキシル−２−ベンゾチアゾリルスルフェンアミド）
加硫促進剤（２）：大内新興化学工業（株）製のノクセラーＮＳ（Ｎ−ｔｅｒｔ−ブチル−２−ベンゾチアゾリルスルフェンアミド） Hereinafter, various chemicals used in Examples and Comparative Examples will be described together.
NR: RSS # 3
BR: Nipol BR1220 (cis content: 95% by mass) manufactured by Nippon Zeon Co., Ltd.
Silica: Ultrasil VN3 manufactured by Evonik Degussa (N ₂ SA: 175 m ² / g)
Carbon black: Seast N220 manufactured by Mitsubishi Chemical Corporation (N ₂ SA: 114 m ² / g)
Silane coupling agent (1): Si75 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa
Silane coupling agent (2): Si363 made by Evonik Degussa (silane coupling agent represented by the following formula (R ^{1 in the} above formula (1) = — O— (C ₂ H ₄ —O) ₅ —C) ^{_{13 H 27, R 2 = C}} 2 H 5 -O-, R 3 = -O- (C 2 H 4 -O) 5 -C 13 H 27, R 4 = -C 3 H 6 -))

Silane coupling agent (3): NXT-Z100 manufactured by Momentive (a polymer consisting only of the binding unit B (in the above formulas (2) and (3), the binding unit A: 0 mol% (x = 0), Bonding unit B: 100 mol%, x + y: 100)
Egg shell powder: Chicken egg shell powder (average particle size 15 μm) manufactured by Kewpie Co., Ltd.
Zinc oxide: Zinc Hana No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Stearic acid “Kashiwa” manufactured by NOF Corporation
Anti-aging agent: Antigen 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
Wax: Sunnock N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Aroma oil: Process X-140 manufactured by Japan Energy Co., Ltd.
Sulfur: Powder sulfur vulcanization accelerator manufactured by Karuizawa Sulfur Co., Ltd. (1): Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Vulcanization accelerator (2): Noxeller NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

Examples 1-8 and Comparative Examples 1-4
In accordance with the formulation shown in Table 1, materials other than sulfur and a vulcanization accelerator were kneaded for 4 minutes at 150 ° C. using a 1.7 L Banbury mixer to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 3 minutes at 80 ° C. using an open roll to obtain an unvulcanized rubber composition. Further, the obtained unvulcanized rubber composition was molded into a tread shape, bonded to other tire members, and vulcanized under conditions of 25 kgf at 150 ° C. for 35 minutes, so that a test studless tire (tire size) 195 / 65R15, DS-2 pattern).

The following evaluation was performed about the obtained unvulcanized rubber composition and the studless tire for a test. The results are shown in Table 1.

(Scorch time)
The obtained unvulcanized rubber composition is subjected to a vulcanization test at a measurement temperature of 170 ° C. using a vibration vulcanization tester (curlastometer) described in JIS K6300, and time and torque are plotted. A vulcanization rate curve was obtained. When the minimum value of torque on the vulcanization speed curve is ML, the maximum value is MH, and the difference (MH−ML) is ME, time t10 (scorch time) (minute) to reach ML + 0.1ME is read, and a comparative example The result of 1 is shown as an index with 100 as the result. The larger the index, the faster the vulcanization is suppressed while preventing the increase in scorch time (decrease in productivity), which is preferable (the scorch time can be adjusted to an appropriate range).

(Abrasion resistance)
The test studless tire was mounted on a 2000cc class passenger car (FR car), the amount of decrease in the groove depth after traveling 30000 km in the city area was measured, and the travel distance when the groove depth decreased by 1 mm was calculated. Furthermore, the abrasion resistance index of Comparative Example 1 was set to 100, and the amount of decrease in the groove depth of each formulation was displayed as an index according to the following formula. In addition, it shows that it is excellent in abrasion resistance, so that an abrasion resistance index | exponent is large.
(Abrasion resistance index) = (travel distance when the groove depth is reduced by 1 mm in each formulation) / (travel distance when the groove of the tire of Comparative Example 1 is reduced by 1 mm) × 100

(On-ice performance (grip performance on the road surface))
Install the test studless tire on a 2000cc class passenger car (FR car), drive on the test course (on ice), step on the lock brake at 30km / h, and calculate the deceleration until the passenger car stops did. Here, the deceleration in the present invention is a distance until the passenger car stops. And the performance index on ice of the comparative example 1 was set to 100, and the deceleration of each compounding was shown as the performance index on ice by the following formula. The larger the performance index on ice, the better the braking performance on the ice road surface, and the better the performance on ice (grip performance on the ice surface). The test place was the Hokkaido Nayoro Test Course of Sumitomo Rubber Industries. The temperature on ice was -1 to -6 ° C.
(On-ice performance index) = (Deceleration of Comparative Example 1) ÷ (Deceleration of each formulation) × 100

Examples including a rubber component containing a specific amount or more of isoprene-based rubber, silica, and a specific silane coupling agent can adjust the scorch time to an appropriate range, performance on ice (grip performance on ice road surface), resistance Abrasion was improved in a well-balanced manner. On the other hand, the comparative example which does not mix | blend the said silane coupling agent was inferior in the balance of on-ice performance (grip performance on an on-ice road surface) and abrasion resistance compared with the Example.

Claims (4)

A rubber component containing 15% by mass or more of isoprene-based rubber;
Silica,
The following formula (1) silane coupling represented by coupling agents and / or the following formula (2) consisting of binding units B represented by the linking unit A and the following formula (3) represented by the silane coupling agent and
A tire rubber composition comprising eggshell powder having an average particle size of 10 to 150 μm .

(In Formula (1), R ¹ is —O— (R ⁵ —O) _m —R ^{6, where} m R ^{5 s} are the same or different and are branched or unbranched C 1-30 divalent. R ⁶ represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or 7 carbon atoms. Represents an aralkyl group of -30. M represents an integer of 1-30.) R ² and R ³ are the same or different and are the same group as R ¹ , branched or unbranched. An alkyl group having 1 to 12 carbon atoms or —O—R ⁷ (R ⁷ is a hydrogen atom, a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, An aryl group having 6 to 30 carbon atoms or an aralkyl group having 7 to 30 carbon atoms is represented. .R ⁴ representing a group represented by in represents a branched or unbranched alkylene group having 1 to 30 carbon atoms.)

(In the formulas (2) and (3), x is an integer greater than or equal to 0. y is an integer greater than or equal to 1. R ⁸ is hydrogen, halogen, a branched or unbranched C1-C30 alkyl group or An alkylene group, a branched or unbranched alkenyl group or alkenylene group having 2 to 30 carbon atoms, a branched or unbranched alkynyl group or alkynylene group having 2 to 30 carbon atoms, or a terminal of the alkyl group or alkenyl group is a hydroxyl group or R ⁹ is substituted with a carboxyl group, R ⁹ is hydrogen, branched or unbranched alkylene group or alkyl group having 1 to 30 carbon atoms, branched or unbranched C 2-30 alkenylene group or alkenyl group, or A branched or unbranched alkynylene group or alkynyl group having 2 to 30 carbon atoms, wherein R ⁸ and R ⁹ form a ring structure. May be.) The tire rubber composition according to claim 1, wherein nitrogen adsorption specific surface area of the silica is 40~250m ² / g. The rubber composition for tires according to claim 1 or 2 used as a rubber composition for treads. The studless tire produced using the rubber composition in any one of Claims 1-3 .