JP2013132977A - Tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire having superior on-ice performance and steering stability on a dry road surface.SOLUTION: A tire includes, in a tread part 1, a block-shaped land part 4 formed with a plurality of siping 5 being formed. The block-shaped land part 4 includes a rubber component (A) and a composite fiber (B) comprising a fiber (B) comprising a hydrophilic fiber and an adhesive layer (B) covering at least a portion of the fiber or a covering layer (B) comprising a resin having hydrophile with respect to the rubber component. The tire uses a rubber composition in which a length of the composite fiber (B) is equal to or more than 1/2 inter-siping distance D and is characterized in that the composite fiber (B) is oriented in a tire circumferential direction.

Description

  The present invention relates to a tire, in particular, a tire excellent in performance on ice and steering stability on a dry road surface.

  Conventionally, in tires mainly used in winter, such as studless tires, the sipe interval is used to soften the tread rubber to improve the trackability of the tread and to improve the drainage effect of the sipe formed on the tread. The performance of a tire on ice is improved by, for example, increasing the density of the tire. However, if the tread rubber is softened or the sipe interval is increased, the block rigidity of the tread is lowered, and the handling stability on the dry road surface is lowered.

  On the other hand, as another method for improving the on-ice performance of a tire, Japanese Patent Application Laid-Open No. 2010-254866 discloses that a rubber composition used for a tread is blended with fine particle-containing fibers and a hydrophilic resin, JP-A 2009-167340 discloses that long air bubbles are oriented in the tire circumferential direction, and a durometer hard such as an olefin resin, a polyamide resin, or an ionomer resin is used in a rubber composition used for a tread. Japanese Patent Application Laid-Open No. 2009-144032 discloses that an ionomer, polyvinyl alcohol, and an ethylene-vinyl alcohol copolymer are added to a rubber composition used for a tread. Disclosure of blending fibers made of hydrophilic resin with contact angle with water such as acrylic resin of 90 ° or less It has been.

JP 2010-254866 A JP 2009-167340 A JP 2009-144032 A

  However, even if the hydrophilic resin is directly blended into the hydrophobic rubber component, or the fibers made of the hydrophilic resin are oriented in the tire circumferential direction, the adhesion between the hydrophilic resin and the hydrophobic rubber component Since there is no affinity, when the block is deformed, the resin or resin fiber slips in the rubber component, and the length is not enough, so even if the resin or resin fiber is blended, the block rigidity can be sufficiently improved. I can't. Therefore, by using the above method, although the performance on the ice of the tire is improved, the steering stability on the dry road surface of the tire cannot be improved.

  Accordingly, an object of the present invention is to provide a tire that solves the above-mentioned problems of the prior art and is excellent in performance on ice and steering stability on a dry road surface. Another object of the present invention is to provide a tire having sufficient wear resistance and excellent performance on ice and steering stability on a dry road surface.

  As a result of intensive studies to achieve the above object, the present inventors have found that a rubber composition used for a tread has a fiber part made of a hydrophilic resin and an adhesive layer or a rubber component covering at least a part of the fiber part. A composite fiber (short fiber) composed of a coating layer made of a resin having an affinity for the resin, and the length of the composite fiber is ½ or more of the inter-sipe distance. By orienting the tire in the tire circumferential direction, it was found that the on-ice performance of the tire was improved and the steering stability on the dry road surface was also improved, and the present invention was completed.

That is, the tire of the present invention includes a block-shaped land portion in which a plurality of sipes are formed in a tread portion,
Affinity for the rubber component (A) and the fiber (B ₁ ) made of a hydrophilic resin and the adhesive layer (B ₂₁ ) or the rubber component covering at least a part of the fiber in the block land portion. A rubber composition comprising a composite fiber (B) made of a coating layer (B ₂₂ ) made of a resin having a length of the composite fiber (B) being ½ or more of the sipe distance. And
The composite fiber (B) is oriented in the tire circumferential direction.

In the suitable example of the tire of this invention, the said hydrophilic resin contains an oxygen atom, a nitrogen atom, or a sulfur atom. Here, the hydrophilic resin contains at least one functional group selected from the group consisting of —OH, —COOH, —OCOR (R is an alkyl group), —NH ₂ , —NCO, and —SH. Further preferred are ethylene-vinyl alcohol copolymers, vinyl alcohol homopolymers or poly (meth) acrylic acid.

In another preferred embodiment of the tire of the present invention, the component contained in the adhesive forming the adhesive layer (B ₂₁ ) is a hydrogen bond or a covalent bond with both the rubber component (A) and the hydrophilic resin. Form. Here, the component contained in the adhesive is more preferably at least one selected from the group consisting of a silane coupling agent, resorcin / formaldehyde / latex, epoxy resin, and chlorosulfonated polyethylene.

  In another preferred embodiment of the tire of the present invention, the resin having affinity for the rubber component is a polyolefin resin. Here, the polyolefin resin is more preferably a polyethylene resin, a polypropylene resin, a polyolefin ionomer, or a maleic anhydride-modified α-polyolefin.

  In the other suitable example of the tire of this invention, the compounding quantity of the said composite fiber (B) is 0.1-100 mass parts with respect to 100 mass parts of said rubber components (A).

  In another preferred embodiment of the tire of the present invention, the rubber composition further contains a foaming agent (C). Here, it is preferable that the foam rate of the block land portion is 5 to 40%.

  According to the present invention, the tread portion is provided with a block-like land portion in which a plurality of sipes are formed, and the block-like land portion is coated with a fiber portion made of a hydrophilic resin and at least a part of the fiber portion. Rubber comprising a composite fiber (B) comprising an agent layer or a coating layer made of a resin having an affinity for a rubber component, wherein the length of the composite fiber (B) is ½ or more of the distance between the sipes The composition is used, and furthermore, a tire excellent in performance on ice and steering stability on a dry road surface in which the composite fiber (B) is oriented in the tire circumferential direction can be provided.

It is a partial top view of the tread part of an example of the tire of the present invention. It is sectional drawing which follows the II-II line of FIG. It is a longitudinal cross-sectional view of an example of die | dye. It is a longitudinal cross-sectional perspective view of an example of a composite fiber (B).

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial plan view of a tread portion of an example of the tire of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. A tread portion 1 of the tire shown in FIG. 1 includes a block land portion 4 defined by a plurality of main grooves 2 extending in the tire circumferential direction and a plurality of lateral grooves 3 extending in the tire width direction. 4, a plurality of sipes 5 extending in the tire width direction are formed. As shown in FIG. 2, the sipe 5 extends in the depth direction of the main groove 2 and the lateral groove 3. 1 is asymmetrical with respect to the tire equatorial plane 6, the tread portion of the tire of the present invention may be symmetrical with respect to the tire equatorial plane. .

Here, in the tire of the present invention, the block-like land portion 4 is coated with a rubber component (A) and a fiber (B ₁ ) made of a hydrophilic resin and an adhesive layer covering at least a part of the fiber ( B ₂₁ ) or a composite fiber (B) comprising a coating layer (B ₂₂ ) made of a resin having an affinity for the rubber component, and the length of the composite fiber (B) is 1 of the inter-sipe distance D. / 2 or more rubber composition is used, and the composite fiber (B) 7 is oriented in the tire circumferential direction.

In the tire of the present invention, a rubber composition containing the rubber component (A) and the composite fiber (B) is used for the block-like land portion 4 in which a plurality of sipes 5 are formed. (B) consists of (i) a fiber (B ₁ ) made of a hydrophilic resin and an adhesive layer (B ₂₁ ) covering at least a part of the fiber, or (ii) a fiber made of a hydrophilic resin. (B ₁ ) and the coating layer (B ₂₂ ) made of a resin having an affinity for the rubber component (A) covering at least a part of the fiber, the composite fiber (B) and the rubber component (A ), And the composite fiber (B) is prevented from sliding in the block land 4. Here, the block-shaped land portion 4, when using a rubber composition containing fibers (B ₁₎ made of a hydrophilic resin, a hydrophilic resin fiber (B ₁₎ and rubber component (A) and the Since the adhesiveness and affinity are low, the fiber (B ₁ ) made of hydrophilic resin is easy to slip in the block land 4 and it is difficult to maintain rigidity by the fiber (B ₁ ) made of hydrophilic resin.

  In addition to the orientation of the composite fiber (B) 7 in the tire circumferential direction, the length of the composite fiber (B) 7 is ½ or more of the inter-sipe distance D. The rigidity in the tire circumferential direction of the portion 4 can be improved. Here, when the length of the composite fiber (B) is less than ½ of the inter-sipe distance D, it is difficult to maintain the rigidity by the composite fiber (B) when the block land portion 4 is stressed.

  As described above, in the tire of the present invention, the rigidity of the block land 4 is improved by the composite fiber (B). Therefore, according to the present invention, the steering stability on the dry road surface of the tire can be improved. In addition, since the rigidity of the block-shaped land part 4 is improving with the composite fiber (B), the tire of this invention is excellent also in abrasion resistance.

Further, in the tire of the present invention, when the tire is used, the fiber (B ₁ ) made of the hydrophilic resin in the composite fiber (B) is exposed on the tread surface, and sufficient affinity with water is ensured. It is possible to impart excellent drainage to the tire. Therefore, according to the present invention, the on-ice performance of the tire can also be improved.

  There is no restriction | limiting in particular as a rubber component (A) of the rubber composition used for the block-shaped land part 4 of the tire of this invention, In addition to natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer Synthetic rubbers such as rubber (SBR), polybutadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene rubber (NBR) can be used. Among these, natural rubber (NR), styrene-butadiene copolymer rubber (SBR), and polybutadiene rubber (BR) are preferable. These rubber components may be used alone or in combination of two or more.

In one embodiment of the tire of the present invention, the rubber composition used for the block land 4 is (i) a fiber (B ₁ ) made of a hydrophilic resin and an adhesive layer (B) covering at least a part of the fiber. ₂₁ ) containing the composite fiber (B). By employing a hydrophilic resin for the fiber, sufficient affinity with water can be ensured, excellent drainage performance can be imparted to the tire, and performance on ice can be improved. In addition, although the affinity with water may reduce the dispersibility of the fiber in the rubber component, in this embodiment, by forming an adhesive layer (B ₂₁ ) on the surface of the fiber (B ₁ ), The dispersibility of the composite fiber (B) in the rubber component (A) and the adhesiveness with the rubber component (A) can be greatly improved, while providing good drainage to the tire, with an excellent dry road surface It is possible to impart a handling stability and wear resistance. Further, the adhesive layer (B _21), the fibers (B ₁₎ of may be formed over the entire surface, it may be formed on a portion of the surface of the fibers (B _1), specifically It is preferable that the adhesive layer (B ₂₁ ) is formed at a ratio of at least 50% of the total surface area of the fibers (B ₁ ).

The components contained in the adhesive forming the adhesive layer (B ₂₁ ) are the rubber component (A) and hydrophilic from the viewpoint of improving the adhesion and affinity between the rubber component (A) and the fiber (B ₁ ). It is preferable to form a hydrogen bond or a covalent bond with both of the functional resins. In this way, the component contained in the adhesive layer (B ₂₁ ) forms not only the rubber component (A) but also the hydrophilic resin that forms the fiber (B ₁ ), thereby forming a hydrogen bond or a covalent bond. While suppressing the uneven distribution of the composite fiber (B) in (A) more effectively, it is possible to ensure stronger adhesion between the rubber (A) and the fiber (B ₁ ), and to disperse well. While maintaining this state, it is possible to further improve the handling and wear resistance on the dry road surface.

  Specifically, the components contained in the adhesive are preferably a silane coupling agent, resorcin / formaldehyde / latex (RFL), epoxy resin, or chlorosulfonated polyethylene, and these may be used alone. You may use in combination of a seed or more. Moreover, you may mix | blend diene rubbers, such as a styrene-butadiene copolymer rubber (SBR), with the said adhesive agent as another component.

  The silane coupling agent is not particularly limited as long as it is usually used in the rubber industry. For example, bis (3-triethoxysilylpropyl) polysulfide, γ-mercaptopropyltriethoxysilane, γ-aminopropyltri In addition to silane coupling agents such as ethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, the following formulas (1) to (7) Examples include silane coupling agents as shown.

［式（１）中、ｎは１〜３の整数、ｍは１〜９の整数、ｐは硫黄原子の平均数を示す、ｐ＞２の整数である。］

[In Formula (1), n is an integer of 1-3, m is an integer of 1-9, p is an integer of p> 2 which shows the average number of a sulfur atom. ]

［式（２）中、ｎ、ｍは式（１）と同義であり、ｑは硫黄原子の平均数を示し、ｑ＜ｐの整数である。］

[In Formula (2), n and m are synonymous with Formula (1), q shows the average number of sulfur atoms, and is an integer of q <p. ]

［式（３）中、Ａは炭素数１〜２０のアルコキシ基又は塩素原子であり、Ｂは炭素数１〜２０のアルキル基であり、Ｘは炭素数１〜９のアルカンジイル基又はアルケンジイル基或いは炭素数７〜１５のアリーレン基であり、Ｘ¹は炭素数１〜２０の飽和又は不飽和アルキル基或いは炭素数６〜１５のアレーンジイル基である。Ｄは、Ａ、Ｂ又は−［Ｏ（ＸＯ）_n］_0.5−基であり、ｎは１〜５の整数で分布を有することがあり、Ｘは前記と同様である。ａ、ｂ及びｄは、０≦ａ≦３．０≦ｂ≦２．０≦ｄ≦１．５、かつ、ａ＋ｂ＋２ｄ＝３の関係を満たす数である。］

[In Formula (3), A is a C1-C20 alkoxy group or a chlorine atom, B is a C1-C20 alkyl group, and X is a C1-C9 alkanediyl group or alkenediyl group. Alternatively, it is an arylene group having 7 to 15 carbon atoms, and X ¹ is a saturated or unsaturated alkyl group having 1 to 20 carbon atoms or an arenediyl group having 6 to 15 carbon atoms. D is A, B or — [O (XO) _n ] _0.5 — group, n may be an integer of 1 to 5 and may have a distribution, and X is the same as described above. a, b, and d are numbers satisfying the relationship of 0 ≦ a ≦ 3.0 ≦ b ≦ 2.0 ≦ d ≦ 1.5 and a + b + 2d = 3. ]

［式（４）中、Ａ、Ｄ、Ｘ、ａ、ｂ、ｄは式（３）に記載されたものから選択され、式（３）と同一でなくてもよく、ＢはＡ、又は炭素数１〜２０のアルキル基である。］

[In the formula (4), A, D, X, a, b and d are selected from those described in the formula (3), and may not be the same as the formula (3), and B is A or carbon. It is a C1-C20 alkyl group. ]

［式（５）中、Ｒ⁵は−Ｃｌ、−Ｂｒ、Ｒ¹⁰Ｏ−、Ｒ¹⁰Ｃ(＝Ｏ)Ｏ−、Ｒ¹⁰Ｒ¹¹Ｃ＝ＮＯ−、Ｒ¹⁰Ｒ¹¹Ｎ−又は−（ＯＳｉＲ¹⁰Ｒ¹¹）_m（ＯＳｉＲ⁹Ｒ¹⁰Ｒ¹¹）（ただし、Ｒ¹⁰及びＲ¹¹は、それぞれ独立に水素原子又は炭素数１〜１８の一価の炭化水素基である。）、Ｒ⁶はＲ⁵、水素原子又は炭素数１〜１８の一価の炭化水素基、Ｒ⁷はＲ⁵、Ｒ⁶又は−［Ｏ（Ｒ¹²Ｏ）_a］_0.5−基（ただし、Ｒ¹²は炭素数１〜１８のアルキレン基、ａは１〜４の整数である。）、Ｒ⁸は炭素数１〜１８の二価の炭化水素基、Ｒ⁹は炭素数１〜１８の一価の炭化水素基を示し、ｘ、ｙ及びｚは、ｘ＋ｙ＋２ｚ＝３、０≦ｘ≦３、０≦ｙ≦２、０≦ｚ≦１の関係を満たす数である。］

[In the formula (5), R ⁵ represents —Cl, —Br, R ¹⁰ O—, R ¹⁰ C (═O) O—, R ¹⁰ R ¹¹ C═NO—, R ¹⁰ R ¹¹ N— or — (OSiR ¹⁰ R ¹¹ ) _m (OSiR ⁹ R ¹⁰ R ¹¹ ) (where R ¹⁰ and R ¹¹ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms), R ⁶ is R ⁵ , a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁷ is R ⁵ , R ⁶ or — [O (R ¹² O) _a ] _0.5 — group (wherein R ¹² is 1 to 1 carbon atoms) 18 is an alkylene group, a is an integer of 1 to 4.), R ⁸ is a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ⁹ is a monovalent hydrocarbon group having 1 to 18 carbon atoms. , X, y, and z are numbers satisfying the relationship of x + y + 2z = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, and 0 ≦ z ≦ 1. ]

［式（６）中、Ｒ¹³は炭素数１〜２０の直鎖もしくは、分岐、環状のアルキル基であり、Ｇはそれぞれ独立して炭素数１〜９のアルカンジイル基又はアルケンジイル基であり、Ｚ^aはそれぞれ独立して二つのケイ素原子と結合することのできる基で、[−Ｏ−]_0.5、[−Ｏ−Ｇ−]_0.5又は[−Ｏ−Ｇ−Ｏ−]_0.5から選ばれる基であり、Ｚ^bはそれぞれ独立して二つのケイ素原子と結合することのできる基で、[−Ｏ−Ｇ−Ｏ−]_0.5で表される官能基であり、Ｚ^cはそれぞれ独立して−Ｃｌ、−Ｂｒ、−ＯＲ¹⁴、Ｒ¹⁴Ｃ(＝Ｏ)Ｏ−、Ｒ¹⁴Ｒ¹⁵Ｃ＝ＮＯ−、Ｒ¹⁴Ｒ¹⁵Ｎ−、Ｒ¹⁴−、ＨＯ−Ｇ−Ｏ−で表される官能基であり、Ｇは上記と同義であり、Ｒ¹⁴及びＲ¹⁵はそれぞれ独立して炭素数１〜２０の直鎖、分岐鎖若しくは環状のアルキル基であり、ｍ、ｎ、ｕ、ｖ、ｗはそれぞれ独立して１≦ｍ≦２０、０≦ｎ≦２０、０≦ｕ≦３、０≦ｖ≦２、０＜ｗ≦１であり、かつ１／２ｕ＋ｖ＋２ｗ＝２又は３である。（Ｉ）部が複数である場合、複数の（Ｉ）部におけるＺ^a _u、Ｚ^b _v及びＺ^c _wそれぞれにおいて、同一でも異なっていてもよく、（ＩＩ）が複数である場合、複数の（ＩＩ）部におけるＺ^a _u、Ｚ^b _v及びＺ^c _wそれぞれにおいて、同一でも異なってもよい。］

Wherein (6), R ¹³ is or straight chain having 1 to 20 carbon atoms, branched or cyclic alkyl group, G is independently an alkanediyl group or an alkenediyl group having 1 to 9 carbon atoms, Z ^a are each independently a group capable of binding with two silicon _{atoms, [- O-] 0.5, [} - O-G-] 0.5 and [-O-G-O-] group selected from _0.5 Z ^b is a group capable of independently bonding to two silicon atoms, and is a functional group represented by [—O—G—O—] _0.5 , and Z ^c is independently Functionalities represented by Cl, —Br, —OR ¹⁴ , R ¹⁴ C (═O) O—, R ¹⁴ R ¹⁵ C═NO—, R ¹⁴ R ¹⁵ N—, R ¹⁴ —, HO—G—O— G is as defined above, R ¹⁴ and R ¹⁵ are each independently a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, m, n, u, v, and w are independently 1 ≦ m ≦ 20, 0 ≦ n ≦ 20, 0 ≦ u ≦ 3, 0 ≦ v ≦ 2, 0 <w ≦ 1, and 1 / 2u + v + 2w = 2. Or 3. When there are a plurality of (I) parts, each of Z ^a _u , Z ^b _v and Z ^c _{w in} the plurality of (I) parts may be the same or different, and when (II) is a plurality, Each of Z ^a _u , Z ^b _v and Z ^c _{w in} part (II) may be the same or different. ]

［式（７）中、Ｒ¹⁶はＲ²¹Ｏ−、Ｒ²¹Ｃ（＝Ｏ）Ｏ−、Ｒ²¹Ｒ²²Ｃ＝ＮＯ−、Ｒ²¹Ｒ²²Ｎ−又は−（ＯＳｉＲ²¹Ｒ²²）_m（ＯＳｉＲ²⁰Ｒ²¹Ｒ²²）（ただし、Ｒ²¹及びＲ²²は、それぞれ独立に水素原子又は炭素数１〜１８の一価の炭化水素基、である）、Ｒ¹⁷はＲ¹⁶、水素原子又は炭素数１〜１８の一価の炭化水素基、Ｒ¹⁸はＲ¹⁶、Ｒ¹⁷又は−[Ｏ（Ｒ²³Ｏ）_a]_0.5−基（ただし、Ｒ²³は炭素数１〜１８のアルキレン基、ａは１〜４の整数である）、Ｒ¹⁹は炭素数１〜１８の二価の炭化水素基、Ｒ²⁰は炭素数１〜１８の一価の炭化水素基を示し、ｘ、ｙ及びｚは、ｘ＋ｙ＋２ｚ＝３、０≦ｘ≦３、０≦ｙ≦２、０≦ｚ≦１の関係を満たす数である。］

[In the formula (7), R ¹⁶ represents R ²¹ O—, R ²¹ C (═O) O—, R ²¹ R ²² C═NO—, R ²¹ R ²² N— or — (OSiR ²¹ R ²² ) _m ( OSiR ²⁰ R ²¹ R ²² ) (where R ²¹ and R ²² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms), R ¹⁷ is R ¹⁶ , a hydrogen atom or carbon A monovalent hydrocarbon group of 1 to ¹⁸ , R ¹⁸ is R ¹⁶ , R ¹⁷ or — [O (R ²³ O) _a ] _0.5 — group (where R ²³ is a C 1-18 alkylene group, a R ¹⁹ is a divalent hydrocarbon group having 1 to 18 carbon atoms, R ²⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and x, y and z are , X + y + 2z = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, and 0 ≦ z ≦ 1. ]

Note that the block-shaped land portion rubber composition, when to be contained and the fibers (B ₁₎ made of a hydrophilic resin adhesive layer covering at least a portion of the fiber composite fibers consisting of (B ₂₁₎ (B) As will be described later, a fiber (B ₁ ) made of a hydrophilic resin together with the rubber component (A) and an adhesive may be mixed and kneaded at once, or a fiber (B made of a hydrophilic resin in advance) After forming an adhesive layer (B ₂₁ ) by applying an adhesive to the surface of ₁ ), the composite fiber (B) may be blended with the rubber component (A) and kneaded. When the fiber (B ₁ ) made of a hydrophilic resin and the adhesive are mixed together with the rubber component (A), the amount of the adhesive is usually 0.01 to 100 with respect to 100 parts by mass of the hydrophilic resin. Part by mass, preferably 0.01 to 40 parts by mass. When the blending amount of the adhesive is within the above range, the adhesive layer (B ₂₁ ) can be effectively formed on the surface of the fiber (B ₁ ) made of the hydrophilic resin mixed together. On the other hand, a composite fiber (B) obtained by forming an adhesive layer (B ₂₁ ) by previously applying an adhesive to the surface of the fiber (B ₁ ) made of a hydrophilic resin is blended with the rubber component (A). In this case, the amount of the composite fiber (B) is usually 0.01 to 100 parts by mass, preferably 0.01 to 40 parts by mass with respect to 100 parts by mass of the rubber component (A). When the compounding amount of the composite fiber (B) is within the above range, it is possible to provide sufficient handling and wear resistance on a dry road surface while maintaining good drainage.

In another embodiment of the tire of the present invention, the rubber composition used for the block-shaped land portion 4 is (ii) a fiber (B ₁ ) made of a hydrophilic resin and a rubber component that covers at least a part of the fiber. A composite fiber (B) comprising a coating layer (B ₂₂ ) made of a resin having an affinity for (A) is included. By employing a hydrophilic resin for the fiber, sufficient affinity with water can be ensured, excellent drainage performance can be imparted to the tire, and performance on ice can be improved. In addition, although the affinity with water may decrease the dispersibility of the fiber in the rubber component, in this embodiment, the rubber is formed by forming the coating layer (B ₂₂ ) on the surface of the fiber (B ₁ ). The dispersibility of the composite fiber (B) in the component (A) can be greatly improved, and it provides excellent handling stability and wear resistance on a dry road surface while imparting good drainage to the tire. be able to. If the softening point of the resin having affinity for the rubber component is lower than the maximum vulcanization temperature, the resin having affinity for the rubber component melts and becomes fluid during vulcanization. The coating layer (B ₂₂ ) contributes to the adhesion between the rubber component (A) and the fibers (B ₁ ), and gives the tire good drainage, excellent handling stability on dry road surfaces, and wear resistance. be able to. Further, the coating layer (B ₂₂₎ may be formed over the entire surface of the fibers (B _1), may be formed on a portion of the surface of the fibers (B _1), specifically, It is preferable that the coating layer (B ₂₂ ) is formed at a ratio of at least 50% of the total surface area of the fibers (B ₁ ).

  As the resin having an affinity for the rubber component, for example, a resin whose solubility parameter (SP value) is close to that of the rubber component (A) can be used, and specifically, a polyolefin-based resin is preferable. The polyolefin-based resin may be branched, linear, or the like, or may be an ionomer resin in which ethylene-methacrylic acid copolymer molecules are crosslinked with metal ions. Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, polystyrene, ethylene-propylene copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene / propylene / diene terpolymer. , Ethylene / vinyl acetate copolymers, and ionomer resins thereof. These may be used alone or in combination of two or more. Among these, polyethylene resin, polypropylene resin, polyolefin ionomer, and maleic anhydride-modified α-polyolefin are particularly preferable. In addition, when polyolefin ionomer or maleic anhydride modified α-polyolefin is used, the rubber strength can be further improved because it adheres to the hydroxyl group.

A composite fiber (B) comprising a fiber (B ₁ ) comprising the hydrophilic resin and a coating layer (B ₂₂ ) comprising a resin having an affinity for the rubber component (A) covering at least a part of the fiber. For example, using an extruder having a die 11 as shown in FIG. 3, a hydrophilic resin is extruded from the die outlet 12, and a resin having affinity for the rubber component is extruded from the die outlet 13, respectively. It can be produced by forming an undrawn yarn and forming the undrawn yarn into a fiber while being hot drawn. In addition, although the usage-amount of each resin may be fluctuate | varied also with the length and diameter of the composite fiber (B) obtained, resin which has affinity with a rubber component with respect to 100 mass parts of hydrophilic resins is usually 0. .1 to 80 parts by mass, preferably 0.1 to 20 parts by mass. By using these resins in an amount within the above range, a coating layer (B ₂₂ ) capable of exerting a desired effect on the surface of the fiber (B ₁ ) made of the hydrophilic resin obtained after the stretching step. It can be formed effectively.

The composite fiber (B) includes a fiber (B ₁ ) made of a hydrophilic resin and a coating layer (B ₂₂ ) made of a resin having affinity for the rubber component (A) covering at least a part of the fiber. As long as it consists of, it will not specifically limit, Various cross-sectional shapes can be employ | adopted. For example, in the case of using an extruder comprising a die 11 as shown in FIG. 3, as shown in FIG. 4 (a), the fiber comprising a composite fiber (B) 7 substantially centered hydrophilic resin (B ₁ ) 14 is located, and the fiber (B ₁ ) 14 made of the hydrophilic resin is covered with a coating layer (B ₂₂ ) 15 made of a resin having an affinity for the rubber component (A) (B) ) Is obtained. Further, as another shape, as shown in FIG. 4B, fibers (B ₁ ) 14 made of a hydrophilic resin are scattered everywhere in the composite fiber (B) 7, and the fiber made of the hydrophilic resin. (B ₁₎ a coating layer comprising a resin having an affinity for 14 a rubber component (a) (B ₂₂₎ 15 and the like shape covering.

It is preferable that the hydrophilic resin used for the fiber (B ₁ ) is insoluble in water. When using the fibers of insoluble hydrophilic resin in water, the fibers in the composite fibers in the tread surface (B) (B ₁₎ fibers in water of the road surface when the part is exposed (B ₁₎ for portion does not dissolve The tread surface hydrophilicity can be maintained over a long period of time, and the tread drainage performance and on-ice performance can be improved over a long period of time.

The hydrophilic resin used for the fiber (B ₁ ) is not particularly limited as long as it is a resin that can exhibit an affinity with water, that is, a resin having a hydrophilic group in the molecule. It is preferably a resin containing an atom, nitrogen atom or sulfur atom, and at least one selected from the group consisting of —OH, —COOH, —OCOR (R is an alkyl group), —NH ₂ , —NCO, —SH. It is more preferable that it is a resin containing a functional group, and it is even more preferable that it is a resin containing at least one functional group selected from the group consisting of —OH, —COOH, —NH ₂ , and —NCO.

Specific examples of the hydrophilic resin used for the fiber (B ₁ ) include ethylene-vinyl alcohol copolymer, vinyl alcohol homopolymer, poly (meth) acrylic acid or ester thereof, polyethylene glycol, carboxyvinyl copolymer. , Styrene-maleic acid copolymer, polyvinyl pyrrolidone, vinyl pyrrolidone-vinyl acetate copolymer, mercaptoethanol and the like are preferable. Among these, ethylene-vinyl alcohol copolymer, vinyl alcohol homopolymer, poly (meth) acrylic An acid is further preferred, and an ethylene-vinyl alcohol copolymer is particularly preferred.

The fiber (B ₁ ) composed of the hydrophilic resin is a known production method, for example, a method in which a hydrophilic resin is melt-spun to form an unstretched yarn, and the unstretched yarn is made into a fiber while being hot-stretched. Can be manufactured. The average length of the obtained fiber (B ₁ ) is usually ½ or more of the inter-sipe distance D of the sipe 5 formed in the tread, preferably 20 mm or less, more preferably 10 mm or less, and the average diameter is usually 0.001 to 2 mm, preferably 0.005 to 0.5 mm. If the average length and the average diameter are within the above ranges, the fibers may not be entangled more than necessary, and the good dispersibility may not be impaired. The aspect ratio is usually 10 to 4000, preferably 50 to 1000. The arpect ratio means the ratio of the major axis to the minor axis of the fiber (B ₁ ).

  Further, the average length of the composite fiber (B) is ½ or more of the inter-sipe distance D of the sipe 5 formed in the tread, preferably 20 mm or less, more preferably 10 mm or less, and the average diameter is usually 0.001-2 mm, preferably 0.005-0.5 mm. When the average length and the average diameter are within the above ranges, the composite fibers (B) are not likely to be entangled more than necessary, and the good dispersibility is not hindered. The aspect ratio is usually 10 to 4000, preferably 50 to 1000. The arpect ratio means the ratio of the major axis to the minor axis of the composite fiber (B).

  The compounding quantity of the said composite fiber (B) is 0.1-100 mass parts normally with respect to 100 mass parts of said rubber components (A), Preferably it is 0.1-50 mass parts. When the compounding amount of the composite fiber (B) is within the above range, it is possible to maintain good drainage and improve on-ice performance while imparting sufficient steering stability and abrasion resistance on a dry road surface. It becomes possible.

  The rubber composition used for the block land 4 may further contain a foaming agent (C). By containing the foaming agent (C), the gas generated from the foaming agent during the vulcanization process is dispersed in the rubber, or the gas is allowed to enter the melted composite fiber (B). Bubbles having a shape corresponding to the shape of (B) can be formed. When such bubbles are present in the rubber, the function as a drainage groove can be exhibited as the tire wears, and further excellent drainage performance can be imparted to the tire. In particular, if bubbles having a shape corresponding to the shape of the composite fiber (B) are formed, the function as a drainage groove can be more suitably exhibited, and the on-ice performance of the tire can be greatly improved.

  Examples of the foaming agent (C) include azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), dinitrosopentastyrenetetramine, benzenesulfonyl hydrazide derivatives, p, p′-oxybisbenzenesulfonyl hydrazide (OBSH). ), Ammonium bicarbonate generating carbon dioxide, sodium bicarbonate, ammonium carbonate, nitrososulfonylazo compound generating nitrogen, N, N′-dimethyl-N, N′-dinitrosophthalamide, toluenesulfonylhydrazide, p- Toluenesulfonyl semicarbazide, p, p′-oxybisbenzenesulfonyl semicarbazide and the like can be mentioned. Among these, from the viewpoint of production processability, azodicarbonamide (ADCA) and dinitrosopentamethylenetetramine (DPT) are preferable, and azodicarbonamide (ADCA) is more preferable. These foaming agents (C) may be used alone or in combination of two or more. Moreover, the compounding quantity of this foaming agent (C) is although it does not specifically limit, The range of 0.1-10 mass parts is preferable with respect to 100 mass parts of rubber components (A). The foaming agent may be included in the fiber.

  The foaming agent (C) is preferably used in combination with foaming aids such as urea, zinc stearate, zinc benzenesulfinate and zinc white. These foaming aids may be used alone or in combination of two or more. By using the foaming aid in combination, it is possible to promote the foaming reaction and increase the degree of completion of the reaction, and to suppress unnecessary deterioration over time.

In addition, in the vulcanized rubber obtained after vulcanizing the rubber composition containing the said foaming agent (C), the foaming rate is 1-100% normally, Preferably it is 5-40%. When the foaming agent (C) is blended, if the foaming rate is too large, the voids on the rubber surface also increase, and there is a possibility that a sufficient adhesion area cannot be secured. Since the amount of bubbles can be appropriately maintained while ensuring the formation of bubbles that function effectively, there is no risk of impairing durability. Here, the foaming rate of the vulcanized rubber means an average foaming rate Vs, and specifically means a value calculated by the following equation (8).
Vs = (ρ ₀ / ρ ₁ −1) × 100 (%) (8)
[In the formula (8), ρ ₁ represents the density (g / cm ³ ) of the vulcanized rubber (foam rubber), and ρ ₀ represents the density of the solid phase part (g / cm ³ ) in the vulcanized rubber (foam rubber). Indicates. ]

  The rubber composition used for the block-shaped land portion 4 is usually used in the rubber industry in addition to the rubber component (A) and the composite fiber (B) as well as the foaming agent (C) and the foaming aid as necessary. The compounding agents used, for example, fillers such as carbon black, softeners, stearic acid, anti-aging agents, zinc white, vulcanization accelerators, vulcanizing agents, etc. are appropriately selected within a range that does not impair the purpose of the present invention. You may select and mix.

In one aspect of the method for producing the rubber composition, the rubber component (A), the fiber (B ₁ ) made of a hydrophilic resin, and the adhesive are mixed at a time. Thereafter, an adhesive having an appropriate affinity for both the hydrophobic rubber component (A) and the fiber (B ₁ ) made of a hydrophilic resin is obtained from the properties of the rubber component (A) through the kneading process. The adhesive layer (B ₂₁ ) is formed on the surface of the fiber (B ₁ ) made of the hydrophilic resin dispersed in the rubber component (A) as a result of entering the gap between the fiber A (A) and the fiber (B ₁ ) made of the hydrophilic resin. ) Is formed. By this method, a rubber composition is obtained through a simple process without adding a new process for forming the adhesive layer (B ₂₁ ) on the surface of the fiber (B ₁ ) made of hydrophilic resin. be able to.

In another embodiment of the method for producing the rubber composition, a composite fiber (B ₂₁ ) formed by previously applying an adhesive onto the surface of the fiber (B ₁ ) made of a hydrophilic resin to form an adhesive layer (B ₂₁ ). B) and the rubber component (A) are mixed. In such a composite fiber (B), an adhesive layer (B ₂₁ ) is formed on the surface of the fiber (B ₁ ) through a drying process or the like by a conventional method. Thus, before mixing with the rubber component (A), the adhesive is applied to the surface of the fiber (B ₁ ) made of the hydrophilic resin in advance, so that it depends on the subsequent steps such as kneading. And the formation of the adhesive layer (B ₂₁ ) on the surface of the fiber (B ₁ ) can be made more reliable.

In another embodiment of the method for producing the rubber composition, a fiber (B ₁ ) made of a hydrophilic resin in advance and a resin having affinity for the rubber component (A) covering at least a part of the fiber. A composite fiber (B) composed of the coating layer (B ₂₂ ) to be prepared is prepared, and the composite fiber (B) is blended with the rubber component (A). In this case, since the coating layer (B ₂₂ ) made of a resin having affinity for the rubber component (A) is formed on the surface of the fiber (B ₁ ) made of a hydrophilic resin in advance, from the initial stage of kneading, Dispersibility of the composite fiber (B) with respect to the rubber component (A) is good.

  The tire according to the present invention is characterized in that the rubber composition is used for the block-shaped land portion 4. The tire of the present invention may be obtained by vulcanization after molding using an unvulcanized rubber composition according to the type and member of the tire to be applied, or semi-vulcanized rubber that has undergone a preliminary vulcanization process or the like. It may be obtained by further vulcanization after use. In addition, as gas with which a tire is filled, inert gas, such as nitrogen, argon, helium other than the air which adjusted normal or oxygen partial pressure, can be used.

In the tire of the present invention, the composite fiber (B) is oriented in the tire circumferential direction. Here, as a method for aligning the orientation of the composite fiber (B), the composite fiber (B) dispersed in the unvulcanized rubber composition may be oriented in a certain direction. using an extruder to reduce towards the outlet, and a method of extruding a rubber composition containing the composite fiber (B) or fibers made of a hydrophilic resin (B _1). Then, a tread rubber is formed from the rubber composition in which the composite fiber (B) is oriented in a certain direction, and the tread rubber is arranged so that the composite fiber (B) is oriented in the tire circumferential direction. The tire of the present invention can be produced by molding and vulcanizing according to a conventional method. The block land portion 4 having a plurality of sipes can be formed in the tread portion 1 by appropriately selecting the shape of the vulcanization mold.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

<Production Example 1: production of fibers made of a hydrophilic resin (B ₁₎ and the coating layer (B ₂₂₎ from become composite fiber (B)>
Using a die 11 as shown in FIG. 3 and a twin screw extruder having two hoppers, an ethylene-vinyl alcohol copolymer [manufactured by Kuraray Co., Ltd., Eval F104B] and polyethylene [manufactured by Nippon Polyethylene Co., Ltd.] , Novatec U360] into separate hoppers, ethylene-vinyl alcohol copolymer from the die outlet 12 and polyethylene from the die outlet 13 are extruded at the same time, and the fiber obtained in accordance with a conventional method has a length of 0.5 mm. Cut into 1 mm, 2 mm, and 3 mm, a composite fiber (B) comprising a fiber (B ₁ ) made of an ethylene-vinyl alcohol copolymer (EVOH) and a coating layer (B ₂₂ ) made of polyethylene (PE) Produced. In addition, the mass ratio of ethylene-vinyl alcohol copolymer (EVOH) and polyethylene (PE) is EVOH: PE = 50: 50, and the fiber diameter is 50 μm.

<Production Example 2: Production of fiber made of resin having affinity for rubber component>
Only the polyethylene is put into the hopper, the polyethylene is extruded from both the die outlet 12 and the die outlet 13, and the fibers obtained in accordance with a conventional method are cut into lengths of 1 mm, 2 mm, and 3 mm, and made of polyethylene (PE). Fibers were made. The fiber diameter is 50 μm.

<Production Example 3: Production of fiber (B ₁ ) made of hydrophilic resin>
Only the ethylene-vinyl alcohol copolymer is introduced into the hopper, the ethylene-vinyl alcohol copolymer is extruded from both the die outlet 12 and the die outlet 13, and the fibers obtained in accordance with a conventional method have a length of 1 mm, 2 mm, Cut to 3 mm, a fiber (B ₁ ) made of an ethylene-vinyl alcohol copolymer (EVOH) was produced. The fiber diameter is 50 μm.

<Production Example 4: Production of fiber made of resin having affinity for rubber component>
Only the ionomer [Mitsui-DuPont Polychemical Co., Ltd., Himiran 1557] was introduced into the hopper, and the ionomer was extruded from both the die outlet 12 and the die outlet 13, and the fibers obtained in accordance with a conventional method had a length of 1 mm and 2 mm. Cut to 3 mm to produce a fiber made of ionomer. The fiber diameter is 50 μm.

<Manufacture example 5: Manufacture of composite fiber (B) formed by coating fiber (B ₁ ) made of hydrophilic resin with adhesive layer (B ₂₁ )>
According to the composition of Table 1, each component of the adhesive was mixed and aged at 25 ° C. for 24 hours to prepare an adhesive solution. This adhesive solution was applied to the surface of B _{1 in} an amount of 20 parts by mass with respect to 100 parts by mass of fibers, dried at 120 ° C. for 1 minute, and then heat-treated at 180 ° C. for 2 minutes. Subsequently, the obtained fiber was cut into a length of 5 mm.

* 1: Nipol 2518GL, manufactured by Nippon Zeon Co., Ltd.
* 2: Nipol LX110 manufactured by Nippon Zeon Co., Ltd.

<Preparation of rubber composition>
A rubber composition having a compounding recipe shown in Table 2 below was prepared using the above fibers.

* 3 “BR01” manufactured by JSR Corporation, cis-1,4-polybutadiene * 4 “Carbon N220” manufactured by Asahi Carbon Corporation
* 5 Ouchi Shinsei Chemical Industry Co., Ltd., “Noxeller DM”, di-2-benzothiazyl disulfide * 6 Sankyo Kasei Co., Ltd., “Cermic AN”, dinitrosopentamethylenetetramine (DPT)

<Production of tire>
The rubber composition was extruded using an extruder in which the cross-sectional area of the flow path decreased toward the outlet, to prepare a tread rubber in which fibers were oriented in a certain direction. Next, the tread rubber is placed in the tread portion so that the fibers in the tread rubber are oriented in the tire circumferential direction, a green tire is formed, vulcanized according to a conventional method, and the tread having the structure shown in FIG. Tire with a size of 195 / 65R15 and an inter-sipe distance D of 2 mm. With respect to the obtained tire, the foaming ratio of the vulcanized rubber forming the tread portion is calculated by the above formula (8), and further, the following methods are used to evaluate the performance on ice, the handling stability on the dry road surface, and the wear resistance. did. The results are shown in Table 3.

(1) Performance on ice In a vehicle equipped with a tire with a tread wear rate of 20%, run on a flat surface on ice, apply a brake at a speed of 20 km / h, lock the tire, and then stop. The braking distance was measured. The reciprocal of the braking distance of the tire of Comparative Example 1 is shown as an index with 100 as the inverse. The larger the index value, the better the braking performance on ice. The wear rate of the tread portion was calculated by the following formula.
Wear rate (%) = (1−groove depth after wear / groove depth when new) × 100

(2) Steering stability on a dry road surface The test tire was attached, the vehicle was run on a dry test course, the driver gave a score, and the score of Comparative Example 1 was shown as an index, which was 100. The larger the index value, the better the steering stability on the dry road surface.

(3) Abrasion resistance After traveling 10,000 km on a paved road surface with a real vehicle using 195 / 65R15 tires, the remaining groove was measured, and the travel distance required for 1 mm of wear on the tread was relatively evaluated. The index is shown as 100.

From the results of Examples 1 to 3 and Examples 4 to 6 in Table 3, a fiber (B ₁ ) made of a hydrophilic resin is coated with a coating layer (B ₂₂ ) made of a resin having an affinity for the rubber component. A rubber composition containing a composite fiber (B) formed by coating a composite fiber (B) or a fiber (B ₁ ) made of a hydrophilic resin with an adhesive layer (B ₂₁ ) is used for the tread portion, Further, it can be seen that by orienting the composite fiber (B) in the tire circumferential direction, the on-ice performance of the tire and the steering stability on the dry road surface can be improved while maintaining the wear resistance.

The comparison with Comparative Example 1 in Table 3 as Examples 1 to 3, or from the comparison between Comparative Example 12 and Examples 4-6, fibers made of a hydrophilic resin (B ₁₎ of the rubber component A composite fiber (B) coated with a coating layer (B ₂₂ ) made of a resin having affinity, or a fiber (B ₁ ) made of a hydrophilic resin coated with an adhesive layer (B ₂₁ ). When the length of the composite fiber (B) is ½ or more of the inter-sipe distance D, the handling stability is improved, but when the length of the composite fiber (B) is less than ½ of the inter-sipe distance D, drying is performed. It can be seen that the handling stability on the road surface does not improve.

Moreover, from the results of Comparative Examples 6 to 8 in Table 3, it is understood that the wear resistance is lowered when a rubber composition containing a fiber (B ₁ ) made of a hydrophilic resin is used for the tread portion.

  Further, from the results of Comparative Examples 9 to 11 in Table 3, when a rubber composition containing a fiber made of ionomer is used for the tread portion, the on-ice performance and steering stability of the tire are improved while maintaining the wear resistance. It can be seen that the range of improvement in performance on ice and steering stability on dry roads is small.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Main groove 3 Horizontal groove 4 Block-shaped land part 5 Sipe 6 Tire equatorial surface 7 Composite fiber (B)
11 Die 12, 13 Die exit 14 Fiber made of aqueous resin (B ₁ )
15 Coating layer made of resin having affinity for rubber component (A) (B ₂₂ )

Claims (11)

In a tire having a tread portion with a block-shaped land portion in which a plurality of sipes are formed,
Affinity for the rubber component (A) and the fiber (B ₁ ) made of a hydrophilic resin and the adhesive layer (B ₂₁ ) or the rubber component covering at least a part of the fiber in the block land portion. Using a rubber composition comprising a composite fiber (B) made of a coating layer (B ₂₂ ) made of a resin having a length of the composite fiber (B) being ½ or more of the distance between the sipes,
A tire characterized in that the composite fiber (B) is oriented in the tire circumferential direction.   The tire according to claim 1, wherein the hydrophilic resin contains an oxygen atom, a nitrogen atom, or a sulfur atom. The hydrophilic resin includes at least one functional group selected from the group consisting of —OH, —COOH, —OCOR (R is an alkyl group), —NH ₂ , —NCO, and —SH. The tire according to claim 2.   The tire according to claim 3, wherein the hydrophilic resin is an ethylene-vinyl alcohol copolymer, a vinyl alcohol homopolymer, or poly (meth) acrylic acid. The component contained in the adhesive forming the adhesive layer (B ₂₁ ) forms a hydrogen bond or a covalent bond with both the rubber component (A) and the hydrophilic resin. The described tire.   The component contained in the adhesive is at least one selected from the group consisting of a silane coupling agent, resorcin / formaldehyde latex, epoxy resin, and chlorosulfonated polyethylene. tire.   The tire according to claim 1, wherein the resin having an affinity for the rubber component is a polyolefin resin.   The tire according to claim 7, wherein the polyolefin resin is a polyethylene resin, a polypropylene resin, a polyolefin ionomer, or a maleic anhydride-modified α-polyolefin.   The compounding quantity of the said composite fiber (B) is 0.1-100 mass parts with respect to 100 mass parts of said rubber components (A), It is characterized by the above-mentioned. tire.   The tire according to claim 1, wherein the rubber composition further contains a foaming agent (C).   The tire according to claim 10, wherein the block land portion has a foaming rate of 5 to 40%.

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