JP2002212339A - Rubber composition for tire tread and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve grip performances on the ice while keeping abrasion resistance of tire. SOLUTION: This rubber composition for tire tread comprises 100 pts.wt. of a diene-based rubber and 3-30 pts.wt. of a poly(2,6-dimethylphenylene oxide) having 1-500 μm average particle diameter. The tire is obtained by using the rubber composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition for a tire tread, and more particularly to a rubber composition for a tire tread having improved grip performance on ice without impairing abrasion resistance.
And a tire using the rubber composition for a tread.

[0002]

2. Description of the Related Art Conventionally, when traveling on a frozen road surface or on snow in a cold region, safety has been ensured by a spike tire having a pin attached to the tire or a tire having a chain attached. However, when these tires were used, the road surface was severely damaged, and the resulting dust caused serious environmental problems. For this reason, the use of spike tires has been banned, and studless tires having braking and driving capabilities on snowy and icy roads have been developed and are now being widely used.

As a studless tire having improved grip performance on ice, for example, there is a tire using a foamed rubber for a tread. However, this tire has good grip performance on icy and snowy roads, but has a problem that the rubber is soft and the block rigidity is reduced due to the influence of the foamed hole portion, and the wear resistance and the performance on general road surfaces are reduced.

[0004] On the other hand, there is a studless tire in which a granular material, for example, sand, ceramic, or the like is blended in rubber to enhance the grip performance on ice by a scratching effect. However, in these tires, since the adhesion between the granular material and the rubber is low, the granular material easily falls off, the scratching effect is not obtained, and not only the braking performance is reduced, but also the wear resistance is reduced. I will. Various adhesives have been studied to compensate for this, but no adhesive having sufficient adhesive strength has been obtained.

Various proposals have been made in the past to solve these problems. However, at present, there is no rubber composition having a high balance between the grip performance on ice and the abrasion resistance.

[0006]

In such a situation,
An object of the present invention is to provide a rubber composition for a tire tread which can improve grip performance on ice while maintaining abrasion resistance, and a tire using the same in a tread.

[0007]

In the present invention, a scratching effect is obtained by adding a poly (2,6-dimethylphenylene oxide) represented by the general formula (1) to a rubber composition for a tire tread. Improves grip performance on roads on snow and ice. Since poly (2,6-dimethylphenylene oxide) forms a chemical bond with the diene rubber via sulfur, the poly (2,6-dimethylphenylene oxide) is very unlikely to fall off. As a result, abrasion resistance can be maintained and good durability can be maintained. Sex can be obtained.

[0008]

Embedded image

(Where n is a positive integer)

That is, according to the present invention, an average particle diameter of 1 to 5 parts per 100 parts by weight of a rubber component comprising a diene rubber is used.
A rubber composition for a tire tread containing 3 to 30 parts by weight of a poly (2,6-dimethylphenylene oxide) represented by the general formula (1) having a styrene unit amount of 10 μm.
Styrene butadiene rubber (SBR) of up to 50% by weight
The rubber composition accounts for 5% by weight or more of the rubber component,
The present invention also relates to a tire using each of the rubber compositions for a tread.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition for a tire tread of the present invention is obtained by adding poly (2,6-dimethylphenylene oxide) represented by the general formula (1) to a rubber component. Grip performance can be improved. Since poly (2,6-dimethylphenylene oxide) is chemically bonded to the rubber component via a vulcanizing agent, the poly (2,6-dimethylphenylene oxide) does not easily fall off and can maintain abrasion resistance.

As the diene rubber, natural rubber and / or diene synthetic rubber is used. As the diene-based synthetic rubber, various rubbers usually used in the rubber industry can be used. For example, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), isoprene rubber (IR ), Chloroprene rubber (CR), butyl rubber (I
IR) and the like.

The diene rubber preferably contains SBR as an essential component and has a styrene unit content of 10 to 5%.
SBR of 0% by weight, preferably 10 to 30% by weight, more preferably 15 to 30% by weight is suitably used. If the styrene unit amount is less than 10% by weight, the adhesiveness to poly (2,6-dimethylphenylene oxide) tends to decrease, and if it exceeds 50% by weight, the grip performance on ice tends to decrease.

The compounding amount of the SBR is 5% by weight or more, more preferably 10 to 100% by weight, particularly preferably 15 to 100% by weight in the rubber component.
Preferably it is 100% by weight. If the content is less than 5% by weight, both abrasion resistance and grip performance on ice tend to decrease.

In the present invention, the average particle diameter is 1 to 50.
0 μm, preferably 1 to 200 μm, more preferably 1 μm
Poly (2,6-dimethylphenylene oxide) of 〜100 μm is used. If it is less than 1 μm, the scratching effect becomes small and sufficient grip performance on ice cannot be obtained.
If it exceeds 500 μm, the wear resistance becomes insufficient.

The amount of poly (2,6-dimethylphenylene oxide) to be added is 3 to 100 parts by weight of the rubber component.
30 parts by weight, preferably 5 to 30 parts by weight, more preferably 5 to 20 parts by weight. If the amount is less than 3 parts by weight, sufficient grip performance on ice cannot be obtained, and if it exceeds 30 parts by weight, the abrasion resistance decreases.

The rubber composition of the present invention contains, in addition to the above components, various chemicals usually used in the rubber industry, for example,
Fillers such as carbon black and silica, silane coupling agents, various vulcanizing agents, various vulcanization accelerators, various softening agents,
Additives such as various antioxidants, zinc oxide, stearic acid, antioxidants, and deterioration inhibitors can be blended.

As the carbon black, a carbon black having a nitrogen adsorption specific surface area (N ₂ SA) of 30 to 300 m ² / g, more preferably 80 to 280 m ² / g can be used. Examples of black include SAF, ISAF, HAF, and the like. When N ₂ SA is less than 30 m ² / g, the reinforcing effect tends to be small and wear resistance tends to decrease, and when N ₂ SA exceeds 300 m ² / g, heat generation tends to increase. When compounding the carbon black, the compounding amount is determined by the rubber component 100
10 to 100 parts by weight, more preferably 20 to 100 parts by weight
Preferably it is 80 parts by weight. If the amount of carbon black is less than 10 parts by weight, the reinforcing effect tends to be small and abrasion resistance tends to decrease.

As the silica, a silica having a nitrogen adsorption specific surface area (N ₂ SA) of 50 to 300 m ² / g, more preferably 100 to 300 m ² / g can be used. Examples thereof include dry-process silica and wet-process silica. N ₂ SA is 50m
Is less than ^{2 /} g, there is a tendency that sufficient elastic modulus decreases the wear resistance is not obtained, and when it is more than 300 meters 2 / ^g, tends to workability kneading despite not expected improvement in grip performance is lowered is there. When compounding silica, the compounding amount is
The amount is preferably 5 to 100 parts by weight, more preferably 10 to 80 parts by weight, based on 100 parts by weight of the rubber component.
If the amount of silica is less than 5 parts by weight, the reinforcing effect tends to be small and the abrasion resistance tends to decrease.

The silane coupling agent can be used to strengthen the bond between the filler and the rubber component and improve the abrasion resistance.

Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, and bis (3-trimethoxysilylpropyl) tetrasulfide. , Bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-
Mercaptoethyltriethoxysilane, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane,
3-chloropropyltriethoxysilane, 2-chloropropyltrimethoxysilane, 2-chloropropyltriethoxysilane, 3-trimethoxysilylpropyl-N,
N-dimethylthiocarbamoyltetrasulfide, 2-
Trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-tri Methoxysilylpropyl methacrylate monosulfide and the like. Of these, bis (3-triethoxysilylpropyl) tetrasulfide and the like are preferable from the viewpoint of both the effect of adding the coupling agent and the cost.

The amount of the silane coupling agent is preferably 2 to 20% by weight based on the weight of the silica. If the amount of the silane coupling agent is less than 2% by weight, the coupling effect tends to be small, and if it exceeds 20% by weight, the coupling effect tends not to be obtained despite the increase in cost. In terms of both the coupling effect and the dispersion effect, the amount of the silane coupling agent is preferably 4 to 15% by weight based on the silica.

The vulcanizing agent is not particularly limited, but various vulcanizing agents such as sulfur, peroxide and non-sulfur compound can be used. The vulcanizing agent may be added in an amount of 0.5 to 10 parts by weight, and more preferably 1 to 8 parts by weight, based on 100 parts by weight of the rubber component. If the compounding amount of the vulcanizing agent is less than 0.5 part by weight, the reinforcing effect tends to be small and abrasion resistance tends to decrease, and if it exceeds 10 parts by weight, grip performance tends to decrease.

The vulcanization accelerator is not particularly restricted but includes, for example, thiazole vulcanization accelerators such as mercaptobenzothiazole and dibenzothiazyldisulfide, N-cyclohexyl-2-benzothiazolylsulfenamide, And vulcanization accelerators such as sulfenamide-based vulcanization accelerators such as N, N'-dicyclohexyl-2-benzothiazolylsulfenamide and guanidine-based vulcanization accelerators such as diphenylguanidine. When compounding a vulcanization accelerator, the compounding amount is 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the rubber component.
It can be by weight. When the compounding amount of the vulcanization accelerator is 0.
If the amount is less than 1 part by weight, the reinforcing effect tends to be small and the wear resistance tends to decrease, and if it exceeds 10 parts by weight, the grip performance tends to decrease.

Examples of the softener include mineral oils such as paraffin oils, naphthenic oils and aromatic oils. When blending mineral oil, the blending amount is from 0 to 100 parts by weight of the rubber component.
100 parts by weight, further 0 to 70 parts by weight, especially 0 to 70 parts by weight
Preferably it is 50 parts by weight. If the amount of the mineral oil exceeds 100 parts by weight, the abrasion resistance tends to decrease.

The tire of the present invention is produced by a usual method using the rubber composition for a tread. That is, the rubber composition containing the various chemicals, if necessary, is extruded in accordance with the shape of each member of the tire in an unvulcanized stage, molded by a normal method on a tire molding machine, Form an unvulcanized tire. The unvulcanized tire is heated and pressed in a vulcanizer to obtain a tire.

The tire of the present invention thus obtained is excellent in balance between abrasion resistance and grip performance on ice.

[0028]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but it should not be construed that the present invention is limited thereto.

The chemicals used in Examples and Comparative Examples are shown below. Natural rubber: Tech Bee Hang Co. RSS # 3 SBR: JSR Co., Ltd. SBR1502 (styrene unit content: 23.5 wt%) Carbon black: Showa Cabot Co. Ltd. SHOWBLACK N220 _(N 2 SA; 125 m ² / g) Aroma oil: JOMO process X140 manufactured by Japan Energy Co., Ltd. Granular material 1: poly (2,6-dimethylphenylene oxide) (average particle diameter: 50 μm) Granular material 2: poly (2,6-dimethyl) (Phenylene oxide) (average particle diameter: 1 mm) Granular material 3: sand (average particle diameter: 300 μm) Antioxidant: Nocrack 6 manufactured by Ouchi Shinko Chemical Co., Ltd.
C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) Stearic acid: Stearic acid manufactured by NOF CORPORATION Zinc oxide: Zinc flower No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: powder sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator: Noxeller C manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Z (N-cyclohexyl-2-benzothiazolylsulfenamide)

The evaluation methods used in the examples and comparative examples will be summarized below. (1) Abrasion resistance Using a Lambourn abrasion tester, the test was performed under the conditions of room temperature, applied load of 1.0 kgf, slip rate of 20%, sandfall of 20 g / min, and measurement time of 5 minutes. The index of Comparative Example 1 was set to 100, and the reciprocal of the amount of wear was indicated by an index. The larger the index, the higher the wear resistance.

(2) Skid performance on ice Skid resistance was measured using a portable skid tester manufactured by Stanley. The measurement conditions were a test room temperature of -3 ° C and a road surface (ice film) temperature of -1 ° C. The skid resistance was expressed as an index, with the index of Comparative Example 1 being 100. A higher index indicates higher skid performance on ice.

(3) Grip performance on ice Tires of 195 / 65R15 having the vulcanized rubber of each of the following Examples and Comparative Examples in the tread were prepared by a conventional method, and were evaluated on an actual road on an ice road surface. The test stability was evaluated by the test driver during steering, and the index of Comparative Example 1 was set to 100 and displayed as an index. The larger the index is, the higher the grip performance on ice is.

Example 1 and Comparative Examples 1-4 According to the formulation shown in Table 1, first, chemicals other than sulfur and a vulcanization accelerator were kneaded and compounded using a 1.7 L Banbury mixer. Sulfur and a vulcanization accelerator were added and kneaded with a roll to obtain various test rubber compositions. These compositions were press-vulcanized at 170 ° C. for 20 minutes to obtain vulcanized products, which were tested for the above-mentioned properties. Table 1 shows the results.

[0034]

[Table 1]

From Table 1, it can be seen that Example 1 in which an appropriate amount of the granular material 1 is blended can improve grip performance on ice while maintaining abrasion resistance as compared with Comparative Example 1 in which no granular material is blended. .

In Comparative Example 2 in which the granular material 2 was blended, Comparative Example 3 in which the granular material 3 was blended, and Comparative Example 4 in which a large amount of the granular material 1 was blended, the abrasion resistance was reduced and the effect of improving the grip performance on ice was reduced. It was small.

[0037]

According to the present invention, it is possible to provide a tire having greatly improved grip performance on ice without deteriorating wear resistance.

Claims (3)

[Claims] 1. A general formula (1) having an average particle diameter of 1 to 500 μm with respect to 100 parts by weight of a rubber component composed of a diene rubber. (Where n is a positive integer)
6-dimethylphenylene oxide) in an amount of 3 to 30 parts by weight. 2. The rubber composition according to claim 1, wherein the styrene-butadiene rubber having a styrene unit content of 10 to 50% by weight accounts for at least 5% by weight of the rubber component. 3. A tire using the rubber composition according to claim 1 for a tread.