JP2002069239A - Rubber composition for tire tread and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a tire tread improved in wet performances combined with snow performances, and a tire using the composi tion. SOLUTION: The rubber composition for a tire tread comprises a rubber component comprising a blend of at least two of (1) 0-30 pts.wt. of a natural rubber(NR), (2) 0-30 pts.wt. of a polybutadiene rubber(BR) and (3) 40-90 pts.wt. of a styrene/butadiene rubber(SBR) having a bound styrene content of 15-45 wt.%, the styrene content in the whole rubber component being 15-30 wt.%, and at least 0.5-10 pts.wt., based on 100 pts.wt. of the rubber component, of a short fiber. The tire is obtained applying the rubber composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for a tire tread and, when used in a tire tread, provides a tire with good wet road performance (braking performance, driveability and steering stability on a wet road surface; hereinafter referred to as "wet performance"). The present invention relates to a rubber composition that provides snow and ice performance (braking property and driving performance on ice and snow road surface; hereinafter, referred to as “snow performance”), and a tire using the same.

[0002]

2. Description of the Related Art A tire running on a general road surface is made of a styrene rubber having a relatively high glass transition temperature as a rubber composition for a tire tread in order to attach importance to wet skid properties and steering stability on a wet road surface such as when it is raining. A rubber composition mainly containing a butadiene copolymer is used. On the other hand, in winter tires, polybutadiene rubber or natural rubber having a low glass transition temperature is mainly used in order to emphasize ice skid or snow skid performance on ice and snow.

[0003] With respect to ice or snow skid performance on icy and snowy roads, it is important to increase the coefficient of friction with the road surface by softening the tread rubber at low temperatures (around -20 ° C). At low temperatures, the storage elastic modulus (E ') of the rubber usually rises and cannot follow the road surface irregularities. Also, on a frozen road surface or the like, the surface unevenness is smaller than that of a normal road surface. The contribution of the energy dissipation (tan δ) occurring between to the skid performance is small. Therefore, it is necessary to increase the true contact area between the rubber and the road surface at a low temperature, and it is more important to lower the storage elastic modulus (E ′) at around −20 ° C. (low elastic modulus). However, when the storage modulus at a low temperature is reduced in this way, the elastic modulus near a room temperature is also reduced at the same time, so that there is a problem that the wet performance at a room temperature is significantly reduced.

For this reason, it has been attempted to suppress the decrease in the wet performance by applying silica as a filler of the tread rubber composition. However, by using silica as the filler, the silica is used in the winter. Although the wet performance of the tire has been improved, it is still insufficient compared with a normal tire used in a normal period (other than winter).

[0005] Incorporation of a large amount of silica not only reduces the workability and productivity in the kneading process, but also increases the electrical resistance of the tread rubber, so that there is no way for static electricity generated in the vehicle to escape. However, since the vehicle remains charged, there are problems such as generation of radio noise and problems caused by static electricity.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention is suitable for a tire tread, and when used in the tire tread, a tread which is excellent in snow performance and prevents a decrease in wet performance, and can supply a tire which sufficiently satisfies the wet performance. An object of the present invention is to provide a rubber composition for use and a tire having excellent snow performance and wet performance by using the rubber composition.

[0007]

Means of the present invention for solving the above problems are as follows. That is, <1> the rubber component is (1) 0 to 30 parts by weight of natural rubber (NR), (2) 0 to 30 parts by weight of polybutadiene rubber (BR), and (3) 40 to 90 parts by weight of Styrene butadiene rubber having a bound styrene content of 15 to 45% by weight (SB
R) and at least two of them are blended,
The styrene content in all the rubber components is 15 to 30% by weight, and 0.5% with respect to 100 parts by weight of the rubber components.
A rubber composition for a tire tread, comprising at least 10 to 10 parts by weight of short fibers. <2> The rubber composition for a tire tread according to <1>, wherein the polybutadiene rubber contains 92% or more of a cis-1,4-structure. <3> The above <1> or <1>, wherein the vinyl bond amount of the butadiene portion of the styrene-butadiene rubber is 7 to 60 mol%.
2> The rubber composition for a tread of a tire according to the above. <4> The rubber composition for a tread of a tire according to any one of <1> to <3>, wherein a part or all of the natural rubber is a synthetic polyisoprene rubber (IR). <5> The rubber composition for a tread of a tire according to any one of <1> to <4>, wherein the short fibers have an average diameter of 0.01 to 0.1 mm. <6> The rubber composition for a tread of a tire according to any one of <1> to <5>, wherein the average length of the short fibers is 0.5 to 10 mm. <7> The rubber composition for a tread of a tire according to any one of <1> to <6>, wherein the short fibers are heat-meltable or heat-softening. <8> The rubber composition for a tread of a tire according to <7>, wherein the short fibers have a melting point or a softening point of 100 to 190 ° C. <9> The above-mentioned <1>, wherein the staple fiber is at least one selected from polyethylene staple fiber, polypropylene staple fiber, aliphatic polyamide staple fiber, aromatic polyamide staple fiber, polyester staple fiber, and polyvinyl alcohol staple fiber.
> The rubber composition for a tread of a tire according to any one of <8>. <10> The rubber composition for a tread of a tire according to any one of <1> to <9>, containing 30 to 90 parts by weight of silica as a filler with respect to 100 parts by weight of the rubber component. <11> Any one of the above items <1> to <10>, which contains 5 to 30 parts by weight of at least one of aluminum hydroxide, alumina and clay as a filler with respect to 100 parts by weight of the rubber component. Rubber composition for tire tread. <12> A tire, comprising the tread rubber composition for a tire according to any one of <1> to <11> in a tread portion of the tire. <13> The tread portion of the tire has a structure in which a plurality of rubber composition layers are laminated in the tire radial direction, and at least one of the rubber composition layers is any one of the above <1> to <11>. The tire according to <12>, comprising the rubber composition for a tread of the tire according to <12>. <14> The short fiber in the tire tread rubber composition is
<12> or <13> oriented in the tire circumferential direction.
The tire described in <>.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a rubber composition for a tread of a tire of the present invention and a tire using the same will be described in detail.

(Rubber Composition) The rubber composition for a tread of the present invention comprises a rubber component and short fibers, and further contains other components appropriately selected as necessary.

In the present invention, 0.5 to 10 parts by weight of short fibers is contained with respect to 100 parts by weight of the rubber component. When the content of the short fiber is less than 0.5 part by weight, the effect of improving the block rigidity of the tread by adding the short fiber is small,
Therefore, the effect of improving the wet performance of the tire is reduced.
On the other hand, when the content of the short fibers exceeds 10 parts by weight, kneading becomes difficult, and workability in the extrusion step is deteriorated.

(Rubber component) The rubber component of the present invention comprises (1)
0-30 parts by weight of natural rubber (NR), (2) 0-30
Parts by weight of polybutadiene rubber (BR);
90 parts by weight of styrene butadiene rubber (SBR) having an amount of bound styrene of 15 to 45% by weight, and at least two kinds thereof are blended. If the NR component exceeds 30 parts by weight, the hysteresis loss becomes small, and the wet performance deteriorates. If the BR component exceeds 30 parts by weight, the hysteresis loss similarly decreases, and the wet performance decreases. The SBR component of the present invention needs to be 40 to 90 parts by weight, and if it is less than 40 parts by weight, the wet performance is reduced, and if it exceeds 90 parts by weight, the snow performance is deteriorated.

The amount of bound styrene of the SBR used in the present invention must be 15 to 45% by weight. If the amount of bound styrene is less than 15%, the hysteresis loss is small, and the wet performance is reduced. On the other hand, if the amount of bound styrene exceeds 45% by weight, the storage elastic modulus (E ') at low temperatures (0 to -20 ° C) becomes high, making it impossible to follow the unevenness of the road surface at low temperatures. Gets worse. This amount of bound styrene can be calculated from the integration ratio of the H-NMR spectrum.

The styrene content in the total rubber component of the present invention must be 15 to 30% by weight. If the styrene content is less than 15% by weight, the hysteresis loss is small and the wet performance is reduced. If the content exceeds 10% by weight, the storage elastic modulus (E ') at a low temperature becomes high, and the snow performance deteriorates.

(BR Rubber) The polybutadiene rubber of the present invention is preferably a so-called high cis content BR containing 92% or more of a cis-1,4-structure. If the cis-1,4-structure content is less than 92 mol%, the effect of improving the skid performance on snow may be insufficient, and good abrasion resistance may not be maintained. However, the cis-1,4-structure content rate is 98
If it exceeds mol%, it is difficult to produce due to the synthesis technology, and the cost becomes high. The content of the cis-1,4-structure can be calculated according to the MORERO method using an infrared spectrophotometer.

(SBR Rubber) The butadiene portion of the styrene butadiene rubber of the present invention preferably has a vinyl bond content of 7 to 60 mol%. If the butadiene part vinyl bond amount is less than 7 mol%, the durability life, particularly the heat generation durability (blowout resistance), may be poor.
If it exceeds mol%, the heat buildup increases, the rolling frictional resistance increases, and the abrasion resistance may deteriorate. The vinyl bond amount means the amount (mol%) of the vinyl bond present in the 1,2-form added one of the butadiene monomer units in the styrene-butadiene rubber. This vinyl bond amount can be measured by an infrared method (MORERO method).

(NR and IR Rubber) In the rubber composition for a tread of the present invention, natural rubber (NR) is used in an amount of 0 to 30 parts by weight as the rubber component. Or a synthetic polyisoprene rubber (I
Even if it is replaced by R), there is almost no difference in the performance as a tire and the workability in the manufacturing process, and thus there is no problem.

(Short Fiber) The average diameter (D) of the short fiber of the present invention is preferably 0.01 to 0.1 mm,
0.01 to 0.05 mm is more preferable.

If the average diameter (D) is less than 0.01 mm, many yarn breaks occur during the production of short fibers.
The effect of blending short fibers tends to be insufficient.
The rigidity of the tread portion may not be sufficiently improved, and the effect of improving the wet performance may not be sufficient. If it exceeds 0.1 mm, the average diameter (D) of the short fibers becomes too large, and the dispersion is poor at the time of rubber kneading. In addition, roughening of the surface during extrusion and disorder in orientation may occur, and the rigidity of the tread portion does not sufficiently improve,
The effect of improving the wet performance may not be sufficient. This is not the case if the average diameter (D) is 0.01 to 0.1 mm. The rigidity of the tread portion can be sufficiently improved, and the snow performance and the wet performance can be both highly balanced. It is preferable in that it becomes possible. The average diameter (D) of the short fibers can be measured using an optical microscope.

The average length (L) of the short fibers of the present invention is preferably 0.5 to 10 mm, more preferably 1 to 5 mm.

If the average length (L) exceeds 10 mm, poor dispersion at the time of rubber kneading, roughening of the surface at the time of extrusion and disorder of orientation occur, the rigidity of the tread portion is not sufficiently improved, and the wet performance is poor. The improvement effect may not be enough,
If it is 10 mm or less, there is no such case, but 0.5 mm
If it is less than mm, mechanical cutting from long fibers becomes difficult, and the productivity of the process for producing short fibers deteriorates.
The effect of blending short fibers tends to be insufficient.
The average length (L) of the short fibers can be measured by, for example, an optical microscope or the like.

Examples of the short fibers include organic short fibers and inorganic short fibers, and any of them can be used. The inorganic short fiber is formed of an inorganic material, and examples thereof include carbon fiber, glass fiber, and steel fiber.
The organic short fiber is formed of a synthetic or natural polymer, and examples thereof include a crystalline short polymer fiber and an amorphous short polymer fiber.

Examples of the crystalline short polymer fibers include polyolefin-based short fibers such as polyethylene, polypropylene and polybutylene, nylon 6, nylon 66, and the like.
Nylon 6-nylon 66 copolymer, nylon 610,
Aliphatic polyamide short fibers such as nylon 612, nylon 46, nylon 11, nylon 12, nylon MXD6, polycondensates of aliphatic diamines and aromatic dicarboxylic acids,
Aromatic polyamide short fiber or aramid short fiber such as Kevlar, polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polyethylene succinate, polyester short fiber such as aromatic polyester, polyvinyl alcohol short fiber such as vinylon, syndiotactic. Tick-1,2-polybutadiene (SPB)
Staple fiber, polyether staple fiber, polyurea staple fiber,
Examples thereof include polyurethane-based short fibers, polyethylene sulfide short fibers, and polyvinyl chloride short fibers. They are,
One type may be used alone, or two or more types may be used in combination.

Examples of the non-crystalline short polymer fibers include polymethyl methacrylate short fibers, acrylonitrile butadiene styrene copolymer short fibers, polystyrene short fibers, and polyacrylonitrile short fibers. These may be used singly or two or more may be used in combination when the short fibers are organic short fibers,
The molecular weight of the resin constituting the organic short fiber varies depending on the chemical composition of the resin, the state of branching of the molecular chains, and the like, and cannot be specified unconditionally. However, the viscosity at the maximum vulcanization temperature of the rubber component (fluid viscosity) It is preferable to select within a range where the viscosity (melt viscosity) of the resin does not become higher than that of the above).

Among the short fibers, organic short fibers which are heat-meltable or heat-softening are preferable, and the crystalline high polymer short fibers are more preferable. Short polyethylene fibers, short polypropylene fibers, short aromatic polyamide fibers, and fats At least one selected from the group consisting of polyamide short fibers, polyester short fibers and polyvinyl alcohol short fibers is particularly preferred.

When the short fibers are heat-meltable or heat-softening, they do not melt or soften at the kneading temperature of the rubber component, but melt or soften at the vulcanization temperature of the rubber component to form short fibers. It is preferable to adhere firmly to the rubber matrix while maintaining the shape. Therefore, the melting point or softening point of the short fibers is preferably lower than the highest vulcanization temperature of the rubber component by 10 ° C. or more, more preferably lower by 20 ° C. or more, and specifically 100 to 190 ° C. Is preferable, and 135 to 180 ° C. is more preferable.

From the viewpoint of the low melting point, the polyethylene short fibers (135 ° C.) and the polypropylene short fibers (170 ° C.) are preferred.

The melting point or the thermal softening point can be measured using a melting point / softening point measuring device known per se. For example, the melting peak temperature measured by using a DSC measuring device is calculated from the melting point or the softening point. It can be a heat softening point.

The content of the short fibers in the rubber composition for tread needs to be 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, and more preferably 1 to 8 parts by weight based on 100 parts by weight of the rubber component. 0.5 to 5.0 parts by weight is more preferred.

When the content of the short fibers is less than 0.5 part by weight, the effect of adding the short fibers cannot be sufficiently obtained, the rigidity of the tread portion does not sufficiently improve, and the wet performance and In some cases, the effect of improving snow performance may not be obtained.
Exceeding the weight part causes poor dispersion during rubber kneading,
Extrusion becomes difficult, so neither is preferred.

As the short fibers, those which are appropriately manufactured may be used, or commercially available products may be used. In the former case, the method for producing the short fibers is not particularly limited,
Depending on the purpose, it can be appropriately selected from known spinning methods, but when the short fibers are organic short fibers, for example, a solution spinning method, a gel spinning method, a melt spinning method and the like are preferably mentioned. Can be The organic short fibers thus obtained are usually
Since it is a long fiber, it can be made into a short fiber used in the present invention by cutting it into a desired length using a cutting tool appropriately selected.

(Silica) In the present invention, silica may be blended with the rubber component as a filler. As the content of silica, based on 100 parts by weight of the rubber component,
It is preferably 30 to 90 parts by weight. If the amount of silica is less than 30 parts by weight, the effect of improving the wet skid performance is insufficient, and if it exceeds 90 parts by weight, kneading becomes difficult, and there is a concern that strength and abrasion resistance may be reduced, Either is not preferable because static electricity is easily generated.

When the above-mentioned silica is blended in the present invention, it is desirable to further add a silane coupling agent in order to strengthen the bond between the silica and the rubber component and to secure abrasion resistance.

Examples of the silane coupling agent used for this purpose include bis (3-triethoxysilylpropyl) polysulfide, bis (2-triethoxysilylethyl) polysulfide, and bis (3-trimethoxysilylpropyl) polysulfide. , Bis (2-trimethoxysilylethyl) polysulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-
Nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2
-Chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl polysulfide,
3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl polysulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl polysulfide, 3-trimethoxysilylpropyl benzothiazole polysulfide, 3-triethoxysilylpropyl benzothiazole Polysulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) polysulfide, 3-mercaptopropyldimethoxymethylsilane, 3-nitropropyldimethoxymethylsilane,
Examples thereof include 3-chloropropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl polysulfide, dimethoxymethylsilylpropyl benzothiazole polysulfide, and the like.

These may be used alone, or
Two or more kinds may be used in combination. Among these, screw (3
-Triethoxysilylpropyl) polysulfide, 3-
Trimethoxysilylpropyl benzothiazole polysulfide and the like are preferred.

The amount of the silane coupling agent is preferably 5 to 20% by weight, more preferably 10 to 15% by weight, based on the amount of the silica.

(Aluminum hydroxide, alumina and clay) The rubber composition of the present invention may further contain at least one of aluminum hydroxide, alumina and clay as a filler with respect to the rubber component. . As the content of these fillers, based on 100 parts by weight of the rubber component,
It is preferably from 5 to 30 parts by weight. When the amount is less than 5 parts by weight, the effect of improving the wet skid performance is insufficient, and when the amount exceeds 30 parts by weight, the abrasion resistance may be deteriorated due to low reinforcing properties.

(Other Components) The rubber composition of the present invention may contain carbon black. At this time, the total amount of carbon black and the silica is preferably 70 to 99 parts by weight based on 100 parts by weight of the rubber component. If the total amount is less than 70 parts by weight, the rigidity may be insufficient. If the total amount is more than 99 parts by weight, abrasion resistance and rolling friction resistance may be deteriorated. When carbon and silica are used in combination, the amount of silica is preferably 45 to 99% by weight of the total amount of carbon black and silica. If the amount of the silica is less than 45% by weight, the wet skid performance may be poor.

In addition to the silica and the carbon black, as a filler, for example, activated calcium carbonate, ultrafine magnesium silicate, high styrene resin, phenol resin, lignin as long as the effects of the present invention are not impaired. A reinforcing material such as a resin, a modified melamine resin, a coumarone indene resin and a petroleum resin, calcium carbonate, basic magnesium carbonate, Lissajous, diatomaceous earth, recycled rubber, and powdered rubber can be blended according to the purpose.

The rubber composition of the present invention may optionally contain
Vulcanizing agents, vulcanization accelerators, vulcanization acceleration aids, antioxidants, process oils, zinc white, stearic acid, and other rubber chemicals normally used in the rubber industry are appropriately selected and kneaded according to the purpose. Is also good.

As the vulcanizing agent, known vulcanizing agents, for example, sulfur, organic peroxides, resin vulcanizing agents, and metal oxides such as magnesium oxide are used.

Examples of the vulcanization accelerator include known vulcanization accelerators such as aldehydes, ammonias, amines, guanidines, thioureas, thiazoles, sulfenamides, thiurams, dithiocarbamates, and xanthates. And the like are used.

Examples of the anti-aging agent include amine-ketone, imidazole, amine, phenol, sulfur and phosphorus compounds.

As the process oil, any of an aroma type, a naphthene type and a paraffin type may be used.

(Production of Rubber Composition) The rubber composition of the present invention comprises a mixture of the rubber component, the short fibers, and the other components appropriately selected as necessary, heating, extrusion, and extrusion. It can be produced by vulcanization or the like.

The conditions for the kneading are not particularly limited, and the procedure for charging into the kneading apparatus, the amount of charge, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time, the type of the kneading apparatus, etc. These conditions can be appropriately selected according to the purpose. The kneading device is not particularly limited, and any of a closed type or an open type can be used. For example, a Banbury mixer (registered trademark), an intermix (registered trademark), a kneader usually used for kneading a rubber composition can be used. , Rolls and the like.

The heating conditions are not particularly limited, and various conditions such as a heating temperature, a heating time, and a heating device can be appropriately selected according to the purpose. Examples of the warming device include, for example, a roll machine usually used for warming a rubber composition.

The conditions for the extrusion are not particularly limited, and various conditions such as an extrusion time, an extrusion speed, an extrusion apparatus, and an extrusion temperature can be appropriately selected according to the purpose. As the extruder, for example, an extruder or the like usually used for extruding a rubber composition for a tire is exemplified. The extrusion temperature can be appropriately determined.

At the time of the extrusion, in order to control the fluidity of the rubber composition, a plasticizer or process oil such as an aroma oil, a naphthene oil, a paraffin oil, an ester oil or the like, a liquid polyisoprene rubber,
A processability improver such as a liquid polymer such as a liquid polybutadiene rubber can be appropriately added to the rubber composition.
In this case, the viscosity of the rubber composition before vulcanization can be reduced, the fluidity thereof can be increased, and extrusion can be performed very well.

There are no particular restrictions on the apparatus, system, conditions and the like for performing the vulcanization, and they can be appropriately selected according to the purpose. As an apparatus for performing the vulcanization, for example, a molding vulcanizer using a mold usually used for vulcanizing a rubber composition for a tire may be mentioned. The temperature of the vulcanization is appropriately determined usually in the range of 100 to 190 ° C.

(Use) The rubber composition of the present invention can be suitably used in various fields. However, since it is excellent in the wet skid performance and the snow skid performance, it can be suitably used for a tire tread. It can be particularly suitably used for the tire of the present invention.

(Tire) The tire of the present invention has at least a tread portion, and the tread rubber composition is contained in the tread portion of the tire. Since the rubber composition for a tread of the present invention has the above configuration,
When the rubber composition is applied to a tread of a tire, the rigidity of the block on the tread surface at normal temperature is increased, and the wet performance is improved. In particular, when the short fibers in the tread rubber composition are oriented in the tire circumferential direction, the circumferential block rigidity of the tread tread at normal temperature is increased, and the effect of improving the wet performance is further increased.

The tread portion of the tire has a structure in which a plurality of rubber composition layers are laminated in the tire radial direction, and at least one of the rubber composition layers is the rubber composition for a tire tread of the present invention. Also in the case of being configured, it is possible to improve wet performance while maintaining tire performances such as wear life, steering stability and rolling resistance at a high level, which is a preferable application example. Also in this case, when the short fibers in the tread rubber composition are oriented in the tire circumferential direction, the effect of improving the wet performance is further increased.

Other than the above, the tire of the present invention is not particularly limited, and the known internal and external configuration of the tire can be employed as it is. An example of such a tire includes a pair of bead portions, a pair of sidewall portions, and a tread portion, and these portions are reinforced by a carcass layer extending between bead cores embedded in the bead portion, and further a crown of the carcass layer is formed. A belt strengthens the tread at the outer periphery. In the tire of the present invention, the tread portion may have a single-layer structure, may include two layers of a cap layer and a base layer, and may have a multilayer structure.

In the tire of the present invention, at least a portion of the tread portion used for the tire, which is in contact with the road surface, is formed of the rubber composition for a tread of the present invention.

The method for producing the tire of the present invention is not particularly limited. For example, first, the rubber composition for a tread of the present invention is prepared, and the rubber composition is applied to a crown portion of a green tire case. It can be manufactured by pasting on an unvulcanized base which has been pasted in advance, and then vulcanizing at a predetermined temperature and a predetermined pressure with a predetermined mold.

The tire of the present invention is a studless tire,
It can also be suitably used for tires for passenger vehicles such as snow tires and all season tires and tires for large vehicles.

[0057]

EXAMPLES In order to clarify the effects of the present invention,
The present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. (Comparative Examples 1 to 4, Examples 1 to 4) A rubber composition for a tread of a tire was prepared with the composition (unit is "parts by weight") shown in Table 1 below. The specifications of the components of the various rubber compositions used in Table 1 are as follows. * 1) BR01: High cis content BR manufactured by JSR Corporation * 2) SBR T0120: Emulsion polymerized SBR manufactured by JSR Corporation (27.3% oil-extended, bound styrene content is 35% by weight) * 3) SBR T0147: Emulsion polymerized SBR manufactured by JSR Corporation (27.3% oil exhibition, bound styrene content is 45% by weight) * 4) C / B Seast 7H: Tokai Carbon Co., Ltd.
* 5) Silica Nipsil AQ: Silica manufactured by Nippon Silica Co., Ltd. * 6) Silane coupling agent Si69: Degussa A
G Coupling agent * 7) Antioxidant: Nocrack 6C from Ouchi Shinko Chemical Co., Ltd. * 8) Vulcanization accelerator: diphenylguanidine * 9) Vulcanization accelerator: dibenzothiazyl sulfide * 10) Polyethylene short fiber: average diameter 0.02m
m, average length 2 mm * 11) Short polypropylene fiber: average diameter 0.02 m
m, average length 2 mm A pneumatic radial tire of size 195 / 65R15 having a tread portion to which the rubber composition having the composition shown in Table 1 was applied was prepared, and the snow performance and wet performance were measured. Also shown in Table 1.

[0058]

[Table 1]

From the results shown in Table 1, it can be seen from Examples 1 to 4 that the rubber composition containing the short fibers of the present invention was applied to a tread.
The tire No. 4 was found to be a high-performance tire capable of maintaining and improving the snow performance and improving the wet performance. In addition, the evaluation test of the tire performed in this Example is as follows. (1) Snow performance test A pneumatic tire for testing is mounted on a domestic 1600CC class passenger car, and the passenger car is driven on a general asphalt road for a distance of 200 km, and then is driven on a flat road on snow.
At a speed of 40 km / h, step on the brakes to lock the tires, measure the distance to stop and the acceleration time from starting the stopped state to reaching 40 km / h,
Based on the results of both, snow performance is indicated by an index, with the tire of Comparative Example 1 taken as 100. The larger the index,
Excellent snow performance. (2) Wet performance test A pneumatic tire for testing is mounted on a domestic 1600CC class passenger car, and the passenger car is driven for 200 km on a general asphalt road, and then is driven on a flat road in rainy weather. The braking performance, straight running stability and controllability were comprehensively evaluated. The results were indexed with the tire of Comparative Example 1 taken as 100. In addition, the larger the numerical value,
This indicates that the wet performance is good.

[0060]

According to the present invention, various problems in the prior art can be solved, which is suitable for a tire tread, and when used in the tire tread, has excellent wet performance and prevents a decrease in snow performance. In addition, it is possible to provide a rubber composition that can sufficiently satisfy snow performance, and a tire excellent in wet performance and snow performance by using the rubber composition.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/34 C08K 3/34 3/36 3/36 // (C08L 9/06 (C08L 9/06 7 : 00 7:00 9:00) 9:00) F term (reference) 4F072 AA02 AB04 AB05 AB06 AD02 AF03 AF06 AL18 4J002 AC012 AC033 AC062 AC081 BB034 BB124 BE024 CF004 CL004 CL064 DE146 DJ016 DJ036 FA044 FD016 GN01

Claims (14)

[Claims] The rubber component comprises (1) 0 to 30 parts by weight of natural rubber (NR), (2) 0 to 30 parts by weight of polybutadiene rubber (BR), and (3) 40 to 90 parts by weight of A styrene butadiene rubber (SBR) having a bound styrene content of 15 to 45% by weight, and at least two kinds thereof are blended, and the styrene content in the rubber component is 15 to 30% by weight, and For 100 parts by weight of the rubber component,
A rubber composition for a tread of a tire, comprising at least 0.5 to 10 parts by weight of short fibers. 2. The polybutadiene rubber is cis-1,
4. The rubber composition for a tread of a tire according to claim 1, wherein the rubber composition contains 92% or more of 4-structure. 3. The styrene-butadiene rubber has a butadiene portion having a vinyl bond amount of 7 to 60 mol%.
Or the rubber composition for a tread of a tire according to 2. 4. The rubber composition for a tire tread according to claim 1, wherein a part or all of the natural rubber is a synthetic polyisoprene rubber (IR). 5. The short fiber according to claim 1, wherein the average diameter of the short fibers is 0.01 to 0.1.
The rubber composition for a tread of a tire according to any one of claims 1 to 4, which is 1 mm. 6. The average length of the short fibers is from 0.5 to 10.
The rubber composition for a tread of a tire according to any one of claims 1 to 5, which is mm. 7. The rubber composition for a tread of a tire according to claim 1, wherein the short fibers are heat-meltable or heat-softening. 8. The short fiber has a melting point or softening point of 100-1.
The rubber composition for a tread of a tire according to claim 7, which is at 90 ° C. 9. The staple fiber is at least one selected from polyethylene staple fiber, polypropylene staple fiber, aliphatic polyamide staple fiber, aromatic polyamide staple fiber, polyester staple fiber, and polyvinyl alcohol staple fiber. 9. The rubber composition for a tread of a tire according to any one of items 1 to 8. 10. With respect to 100 parts by weight of the rubber component,
The rubber composition for a tread of a tire according to any one of claims 1 to 9, comprising 30 to 90 parts by weight of silica as a filler. 11. With respect to 100 parts by weight of the rubber component,
The rubber composition for a tread of a tire according to any one of claims 1 to 10, further comprising 5 to 30 parts by weight of at least one of aluminum hydroxide, alumina, and clay as a filler. 12. A tire comprising the tire tread rubber composition according to any one of claims 1 to 11 in a tread portion of the tire. 13. The tire tread portion has a structure in which a plurality of rubber composition layers are laminated in the tire radial direction, and at least one of the rubber composition layers is in any one of claims 1 to 11. The tire according to claim 12, comprising a rubber composition for a tread of the tire of (1). 14. The tire according to claim 12, wherein the short fibers in the tire tread rubber composition are oriented in the tire circumferential direction.