JP2002060548A - Rubber composition for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for tire tread having improved frictional force on ice. SOLUTION: This rubber composition for tire tread comprises 100 pts.wt. of diene rubber, 1-20 pts.wt. of thermally expandable thermoplastic resin particles that include thermally expandable substance with particle size of 5-300 μm and 1-30 pts.wt. of spherical particles that mainly including silicate salt with an average particle size of 30-300 μm or non-spherical powder particles of a metal carbonate salt, a metal sulfate salt and/or aluminum oxide with an average particle size of 10-200 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a tire, and more particularly, to a diene rubber having a heat-expandable microcapsule, a silicate having a specific particle size, a metal carbonate having a specific particle size, a metal sulfate, and an oxidizing agent. The present invention relates to a rubber composition for a tire capable of improving on-ice performance of a tire such as frictional force on ice obtained by blending powder particles containing aluminum as a main component.

[0002]

2. Description of the Related Art Spike tires conventionally used as tires for icy and snowy roads exhibit excellent gripping power,
In recent years, studless tires without spikes have been used for icy and snowy roads instead of spiked tires due to dust pollution. However, compared to spiked tires, studless tires have insufficient frictional force between the tread surface and the icy and snowy road surface, and various improvements have been proposed.

For example, JP-A-61-106686 discloses a rubber composition containing diatomaceous earth or zeolite, and JP-A-2-170840 discloses a rubber composition containing fine hollow spheres. JP-A-4-246440 discloses a rubber composition containing heat-expandable microcapsules. Further, Japanese Patent Application Laid-Open No. 9-302153 describes a rubber composition containing porous particles.
Japanese Patent Laid-Open Publication No. H11-17583 discloses a rubber composition containing heat-expandable microcapsules. In addition, JP-A-2-20833
No. 6 and JP-A-4-055443 disclose a rubber composition containing hollow fine particles, which is disclosed in JP-A-9-128779.
And JP-A-9-128889 disclose a rubber composition containing heat-expandable microcapsules.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber composition for a tire having further improved on-ice performance such as the above-mentioned frictional force on ice.

[0005]

According to the present invention, 100 parts by weight of a diene rubber, 1 to 20 parts by weight of thermally expandable thermoplastic resin particles having a particle diameter of 5 to 300 μm and containing a substance which undergoes volume expansion by heat. And a rubber composition for a tire, comprising 1 to 30 parts by weight of spherical powder particles mainly composed of silicate having an average particle diameter of 30 to 300 μm.

According to the present invention, 100 parts by weight of a diene rubber and a particle size containing a substance which undergoes volume expansion by heat are included.
1 to 20 parts by weight of thermally expandable thermoplastic resin particles having a particle size of 1 to 30 and a non-spherical powder particle 1 to 30 having a mean particle size of at least one of a metal carbonate, a metal sulfate and aluminum oxide as main components. There is provided a rubber composition for a tire, comprising a weight part.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors can obtain a rubber composition whose frictional force on ice has already been improved by blending a heat-expandable microcapsule, when further blending powder particles having a smaller particle diameter. It has been found that a synergistic effect of improving the performance of the rubber composition is low, while a synergistic effect of improving the performance of the obtained rubber composition can be obtained when powder particles having a relatively large particle diameter are blended. It is preferable that the powder particles to be added have a large specific surface area, and silicates, metal carbonates, metal sulfates,
Examples include powder particles containing aluminum oxide as a main component. Actually, in the case of particles having a spherical shape, the average particle diameter is 30 to 300 μm, preferably 40 to 100 μm, and non-spherical particles whose particle shape is not spherical are 10 to 200 μm,
Preferably, particles having a particle size of 20 to 60 μm are effective. Specifically, spherical particles mainly composed of diatomaceous earth, metal carbonates such as basic magnesium carbonate, calcium carbonate and barium carbonate, precipitated barium sulfate, aluminum sulfate and the like can be used. Non-spherical particles such as metal sulfate, aluminum oxide, and aluminum hydroxide are included.

The diene rubber compounded in the rubber composition of the present invention may be any diene rubber conventionally used for tire treads, for example, natural rubber (NR), polyisoprene rubber (IR), various styrenes -Butadiene copolymer rubber (SBR), various polybutadiene rubbers (B
R), acrylonitrile-butadiene copolymer rubber and the like, and these can be used alone or as an arbitrary blend.

The rubber composition of the present invention further comprises a heat-expandable thermoplastic resin in which a liquid or a solid which generates a gas by vaporization, decomposition or chemical reaction by heat is enclosed with respect to 100 parts by weight of the diene rubber. 1 particle (microcapsule)
-20 parts by weight, more preferably 5-10 parts by weight. If the amount is too small, the desired effect cannot be obtained, which is not preferable. On the contrary, if the amount is too large, the wear resistance deteriorates, which is not preferable.

[0010] The heat-expandable thermoplastic resin particles are a heat-expandable thermoplastic resin particle in which a liquid or a solid which generates a gas by being vaporized, decomposed, or chemically reacted by heat is contained in the thermoplastic resin. Temperature, for example 140-19
Heated and expanded at a temperature of 0 ° C., the gas is sealed in an outer grain made of the thermoplastic resin, and the particle size of the gas-encapsulated thermoplastic resin particles is 5 to 300 μm, preferably It is 10 to 100 μm.

Such thermally expandable thermoplastic resin particles (unexpanded particles) include, for example, E.
Product name "EXPANCEL 091D" from XPANCEL
U-80 "or" Expancel 092DU-12 "
0 "or the like, or from Matsumoto Yushi Co., Ltd. under the trade name" Matsumoto Microsphere F-85 "or" Matsumoto Microsphere F-100 ".

The thermoplastic resin constituting the outer grain component of the gas-filled thermoplastic resin particles has an expansion start temperature of 100 ° C. or higher, preferably 120 ° C. or higher, and a maximum expansion temperature of 150 ° C. or higher, preferably Those having a temperature of 160 ° C. or higher are preferably used. As such a thermoplastic resin, for example, a polymer of (meth) acrylonitrile or a copolymer having a high content of (meth) acrylonitrile is suitably used. As other monomers (comonomer) in the case of the copolymer, monomers such as vinyl halide, vinylidene halide, styrene-based monomer, (meth) acrylate-based monomer, vinyl acetate, butadiene, vinylpyridine, and chloroprene are used. . In addition, the said thermoplastic resin is divinylbenzene, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, It may be made crosslinkable with a crosslinking agent such as allyl (meth) acrylate, triacrylformal, triallyl isocyanurate and the like. The crosslinked form is preferably not crosslinked, but may be partially crosslinked so as not to impair the properties as a thermoplastic resin.

The liquid or solid which is vaporized, decomposed, or chemically reacted by heat to generate a gas includes, for example, n-
Liquids such as hydrocarbons such as pentane, isopentane, neopentane, butane, isobutane, hexane, petroleum ether, chlorinated hydrocarbons such as methyl chloride, methylene chloride, dichloroethylene, trichloroethane, and trichloroethylene, or azodicarbonamide; Solids such as dinitrosopentamethylenetetramine, azobisisobutyronitrile, a toluenesulfonylhydrazide derivative, and an aromatic succinylhydrazide derivative are exemplified.

The rubber composition of the present invention may contain, as a rubber reinforcing agent, any carbon black usually added to the rubber composition. Carbon black surface-treated with silica can also be used. Silica can also be used. The amount of the carbon black is 20 to 80 parts by weight based on 100 parts by weight of the diene rubber.
It is used in parts by weight, preferably 30 to 60 parts by weight. If the amount is too small, the rubber cannot be satisfactorily reinforced. For example, the friction resistance is deteriorated, which is not preferable. On the contrary, if the amount is too large, the hardness becomes too high and the workability is deteriorated. Silica, especially precipitated silica is 0 to 50 parts by weight per 100 parts by weight of diene rubber,
Preferably, 5 to 20 parts by weight are blended. Silica may not be used, and if used, it is preferable to use a compounding amount in a range that improves the balance of tan δ. If it is too large, the electric conductivity decreases and the cohesive force of the reinforcing agent increases. However, dispersion during kneading becomes insufficient, which is not preferable.

In the present invention, any carbon black conventionally used for tires can be used, but the nitrogen adsorption specific surface area (N ₂ SA) is 70 m ^2.
/ G, preferably 80-200 m ² / g, and a dibutyl phthalate oil absorption (DBP) of 90 ml / 100 g or more, more preferably 100-150 ml / 100 g.

The rubber composition for a tire according to the present invention further comprises a usual vulcanizing or crosslinking agent, a vulcanizing or crosslinking accelerator,
Various oils, anti-aging agents, fillers, plasticizers, and other various additives that are generally compounded for general rubber can be compounded, and such a compound is kneaded by a general method.
The composition can be vulcanized and vulcanized or crosslinked. The amounts of these additives may be conventional general amounts as long as the object of the present invention is not adversely affected.

[0017]

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

Preparation of Samples Comparative Examples 1-2 and Examples 1-3 Using a 1.7 liter closed Banbury mixer,
Of the formulations (parts by weight) shown in Table I, diatomaceous earth, magnesium carbonate, or activated alumina was mixed with a compounding agent such as rubber and carbon black for 5 minutes, and then, with an open roll, a vulcanization accelerator, sulfur and Microcapsules were blended.

[0019]

[Table 1]

The ingredients used in Examples 1-3 and Comparative Examples 1-2 are as follows. ^* 1 NIPOL 1220: Polybutadiene rubber manufactured by Zeon Corporation, glass transition temperature = −101 ° C. ^* 2 SHOBLACK N220: Carbon black manufactured by Showa Cabot Corp., N ₂ SA: 111 m ² /
g, DBP oil absorption: 111 ml / 100 g ^* 3 SANTOFLEX 6PPD: FLEXSIS
Antioxidants ^* 4 Zinc oxide No.3: manufactured by Shodo Chemical Co., Ltd. ^* 5 Stearic acid: manufactured by NOF ^* 6 Aroma oil: manufactured by Fujikosan ^* 7 SANTOCURE NS: manufactured by FLEXSIS
Vulcanization accelerator ^* 8 Sulfur: 5% oil-extended sulfur manufactured by Karuizawa Seirensho Co., Ltd. ^* 9 Microsphere-F100D: Matsumoto Yushi Thermal expandable resin particles ^* 10 Diatomaceous earth: Kanto Chemical Co.
(Average particle size: 45 μm) ^* 11 Magnesium carbonate: manufactured by Tokuyama Soda (non-spherical particles,
Average particle size: 60 μm ^* 12 Activated alumina: Nippon Light Metal's ordinary alumina A1
1 (non-spherical particles, average particle size: 50 μm)

Next, the composition was placed in a size of 15 × 15 × 0.2 cm.
A test specimen (rubber sheet) was prepared by press vulcanization at 175 ° C. for 10 minutes in a mold, and the frictional properties on ice (−1.5 ° C. and −3 ° C.) and friction performance as vulcanization properties were measured. evaluated. The results are shown in Table II.

[0022]

[Table 2]

The vulcanized sheet of each compound was attached to a flat cylindrical base rubber, and measured at −3.0 ° C. and −1.5 ° C. with an inside drum type friction tester on ice at a load of 5.5 kg / cm. ^3. Friction coefficient on ice was measured at a drum rotation speed of 25 km / h.

[0024]

As described above, according to the present invention, according to the present invention, the heat-expandable microcapsules and the silicate, the spherical particles or the metal carbonate, the metal sulfate and / or the metal sulfate having the specific particle size are added to the diene rubber. By blending powder particles mainly composed of non-spherical particles of aluminum oxide, a rubber composition for a tire having an improved frictional force on ice can be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 7/18 C08K 7/18 // (C08L 9/00 (C08L 9/00 101: 00) 101: 00) (72) ) Inventor Takeshi Hotaka 2-1 Oiwake, Hiratsuka-shi, Kanagawa F-term in Hiratsuka Works of Yokohama Rubber Co., Ltd. 4J002 AC011 AC031 AC061 AC071 AC081 BG102 DE146 DE236 DG046 DJ006 FA086 FB282 FD016 GN01

Claims (2)

[Claims] 1. 100 parts by weight of a diene rubber, 1 to 20 parts by weight of thermally expandable thermoplastic resin particles having a particle diameter of 5 to 300 μm containing a substance which undergoes volume expansion by heat, and a silicate having an average particle diameter of 30 to 300 μm. A rubber composition for a tire, comprising 1 to 30 parts by weight of spherical powder particles containing as a main component. 2. 100 parts by weight of a diene rubber, 1 to 20 parts by weight of thermally expandable thermoplastic resin particles having a particle diameter of 5 to 300 μm containing a substance which undergoes volume expansion by heat, and metal carbonate having an average particle diameter of 10 to 200 μm. A rubber composition for a tire, comprising 1 to 30 parts by weight of non-spherical powder particles containing at least one of a salt, a metal sulfate and aluminum oxide as main components.