JPH10195242A - Rubber composition for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition for a tire having an increased wet-grip properties without increasing rolling resistance by allowing a diene-based rubber to include a specific amount of a specified polymer resin. SOLUTION: This rubber composition for a tire is obtained by formulating (A) 100 pts.wt. diene-based rubber (e.g. a styrene-butadiene copolymer rubber) with (B) 3-60 pts.wt. polymer resin having 5-100 deg.C glass transition temperature and consisting essentially of an aromatic vinyl compound as a softening agent, and (C) optionally 30-110 pts.wt. carbon black, sulfur, a vulcanization accelerator, an antioxidant, a filter, a plasticizer, etc. The component B is, for example, a homopolymer of an aromatic vinyl compound (e.g. α-methylstyrene), a copolymer of the compounds or the compounds and other comonomer (e.g. isoprene) or a blend of a resin thereof with a copolymer resin including 5C or 9C fraction obtained by thermal cracking of a naphtha.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition for a tire, and more particularly, to a rubber composition for a tire having improved wet grip without substantially deteriorating the rolling resistance of the tire.

[0002]

2. Description of the Related Art In recent years, it has been desired to improve wet grip of tires of automobiles and the like from the viewpoint of environmental hygiene, energy, and the like, and various studies have been conventionally made to enhance wet grip performance. For example, a rubber having a high glass transition temperature Tg is used as the rubber to be compounded, or a compounding amount of carbon black is increased,
It has been proposed to use carbon black having a small particle size or blend a resin having a high softening point. However, these methods are not preferable because they cause a problem of deteriorating rolling resistance.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rubber composition for a tire which has improved wet grip performance of the tire without substantially increasing the rolling resistance of the tire characteristics. .

[0004]

According to the present invention, 100 parts by weight of a diene rubber and a glass transition temperature Tg of 5 to 10 are used.
Polymer resin containing an aromatic vinyl compound at 0 ° C. as a main component 3
The present invention provides a rubber composition for a tire, comprising from about 60 parts by weight.

[0005]

According to the present invention, tan δ at 60 ° C. is reduced by blending a diene rubber or a rubber component containing the same as a main component with a polymer resin containing an aromatic vinyl compound as a main component. Since there is no substantial change, the rolling resistance of the tire is not substantially adversely affected, and tan δ at 0 ° C. is increased, so that the wet grip performance of the tire can be improved.

The diene rubber used in the present invention is:
Any diene rubber conventionally used for tires, for example, natural rubber (NR), polyisoprene rubber (IR), various styrene-butadiene copolymer rubbers (S
BR), various polybutadiene rubbers (BR), acrylonitrile-butadiene copolymer rubbers and the like, and these can be used alone or as an arbitrary blend. Further, the rubber component used in the rubber composition for a tire of the present invention includes, in addition to the diene rubber, another diene rubber or an ethylene-propylene polymer rubber (EPR, EPD).
M), a polyisobutylene-based polymer rubber (IIR, halogenated IIR) and the like can also be blended.

According to the present invention, 3 to 60 parts by weight, preferably 5 to 30 parts by weight of a softener resin is blended with respect to 100 parts by weight of the rubber component comprising the diene rubber. Examples of such a softener resin include a homopolymer of an aromatic vinyl compound (for example, α-methylstyrene, styrene whose nucleus is substituted with a methyl group, an ethyl group, a propyl group, or the like), α-methylstyrene, or a homopolymer thereof. Copolymer resins with other comonomers (eg, isoprene, cumarone, indene, dicyclopentadiene, etc.) or blends of these resins with copolymer resins containing C ₅ or C ₉ fractions obtained by pyrolysis of naphtha And so on. As such resins, for example, alpha-methyl styrene resin, vinyl toluene resin, alpha-methylstyrene - such as by increasing the vinyl toluene copolymer resin, and a mixture or copolymer resin of these resins and C ₅ or C ₉ resin Can be.

The softener resin used in the present invention has a glass transition temperature Tg of 5 to 100 ° C., preferably 15 to 8 ° C.
0 ° C. If the Tg is less than 5 ° C., the softening temperature of the resin may be too low and blocking may be likely to occur, which makes the handling difficult. Therefore, if it exceeds 100 ° C., the rolling resistance deteriorates and the Mooney viscosity decreases. It is not preferable because it becomes high and the workability deteriorates. If the amount of the softener resin is too small, the desired effect cannot be obtained, while if it is too large, the processability becomes poor, which is not preferable.

The rubber composition for a tire according to the present invention includes:
In addition to the above essential components, carbon black is added
Per 100 parts by weight, preferably 30 to 110 parts by weight, more preferably 40 to 100 parts by weight can be added.
As the carbon black, carbon black conventionally used for tires can be used.

The rubber composition for a tire according to the present invention further comprises sulfur, a vulcanization accelerator, an antioxidant, a filler, a softener,
Various additives generally used for tires and the like, such as a plasticizer, can be compounded. The rubber composition of the present invention can be vulcanized by a general method to obtain a tire.

[0011]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but it goes without saying that the scope of the present invention is not limited to these Examples.

Examples 1 to 10 and Comparative Examples 1 to 6 Each of the components (parts by weight) shown in Table I was blended to produce a rubber composition.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

[0016]

[Table 4]

The resin components shown in Table I are as follows. YXLON G-90 (Cumaron indene resin manufactured by Nippon Steel Chemical Co., Ltd., Tg = 25 ° C.) Endex 160 (polymer resin of aromatic vinyl compound manufactured by Rika Hercules, Tg = 103 ° C.) Petrochemical Co., Ltd. aromatic vinyl compound polymer resin, Tg = 15 ° C.) FTR7080 (Mitsui Petrochemical Co., Ltd. aromatic vinyl compound / C ₅ fraction copolymer resin, Tg = 15 ° C.) FTR6100 FTR0120 (Mitsui Petrochemical Co., Ltd. α-methylstyrene polymer resin, Tg = 60 ° C) FTR9135 (Mitsui Petrochemical Co., Ltd.) Kogyo KK aromatic vinyl compound / C ₅ fraction / C ₉ fraction copolymer resin, Tg =
70 ° C)

The other components shown in Table I are as follows. NIPOL-9529 (SBR (styrene-butadiene) manufactured by Zeon Corporation, Tg = -21 ° C) RSS # 1 (natural rubber) N330 (carbon black manufactured by Tokai Carbon Co., Ltd.)
Seast 3) TBBS (vulcanization accelerator: N-tert-butyl-2-benzothiazolesulfenamide) Aroma oil (Process X-1 manufactured by Japan Energy Co., Ltd.)
40)

Other components except for sulfur and the vulcanization accelerator were:
Knead with an 8 liter closed mixer for 3-5 minutes.
The masterbatch released when the temperature reached 5 ± 5 ° C. was kneaded with a vulcanization accelerator and sulfur with an 8-inch open roll to obtain a rubber composition. This composition was press-vulcanized in a 15 × 15 × 0.2 cm mold at 160 ° C. for 20 minutes to prepare a target test piece (rubber sheet), and the following physical properties were evaluated.
The results are shown in Table I.

Mooney viscosity (ML _{1 + 4} ): JIS K
Measured according to 6300. The preheating time was 1 minute and the test time was 4 minutes using an L rotor. tan δ (0 ° C. and 60 ° C.): tan δ at 0 ° C. and 60 ° C. was measured according to JIS K 6394.

[0021]

As described above, according to the present invention, T
By using a polymer resin whose main component is an aromatic vinyl compound having a g of 5 to 100 ° C. as a softening agent for a diene rubber, it is possible to improve the grip performance during running of a tan δ tire while maintaining rolling resistance. The effect that it can be obtained is obtained.

Claims (1)

[Claims] 1. A tire rubber composition comprising 100 parts by weight of a diene rubber and 3 to 60 parts by weight of a polymer resin containing an aromatic vinyl compound having a glass transition temperature Tg of 5 to 100 ° C. as a main component.