JPH0715028B2 - Tread rubber composition for tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tread rubber composition for tires.

(Prior Art) Conventionally used spike tires are skid resistant,
Traction is good, but general pavement road surface is scraped,
The dust that results is a problem.

(Problems to be solved by the invention) An object of the present invention is to solve the above-mentioned problems on a general pavement surface, to provide a tire tread rubber composition which is a non-spiked tire and is excellent in both ice performance and snow performance. To provide.

(Means for Solving the Problem) The present invention provides a tread rubber composition for tires, wherein diene rubber is mixed with at least one of silica and carbon black, and the extractable component (E) defined below is represented by formula (1). And the average particle size of 0.01 to 5 mm of the pulverized plant is a rubber component 100 after extraction of the following vulcanized rubber with acetone chloroform.
The present invention relates to a tread rubber composition for tires, which is used in an amount of 3 to 50 parts by weight based on parts by weight.

E> 1.2 (A-38) (1) E: 100 parts of vulcanized rubber after extraction with acetone / chloroform
Part by weight of the acetone-chloroform extract relative to parts by weight A: 100 parts of the vulcanized rubber after extraction with acetone-chloroform
As a diene rubber component of the rubber composition of the present invention, natural rubber (NR), butadiene rubber (BR), styrene butadiene rubber (SBR), and isoprene are used. Rubber (IR), butyl rubber (II
R) and blends thereof can be used. At least one of silica and carbon black is blended in the rubber component. Silica and carbon black are rubber
30 to 80 parts, preferably 35 to 55 parts are preferably added to 100 parts (parts by weight, the same applies hereinafter).

The softness of the rubber is one of the characteristics that determines the performance of the rubber composition on ice. The softness is related to the weight part of oil, and the oil content of the rubber composition can be determined by extraction with acetone-chloroform. On the other hand, conversely, if a reinforcing filler is blended, the rubber becomes hard and the performance on ice decreases, but
Reinforcing fillers are necessary to enhance mechanical performance. Therefore, as a result of studying the softness and hardness in order to exert the performance on ice, the formula (1) of the present invention was reached.
Carbon black and silica are used as rubber reinforcing fillers, but since the reinforcing effect of silica is about half that of carbon black N220, which is usually used in the tread formulation of heavy duty radial tires, silica is part by weight of carbon black. The hardness effect was reduced to 1/2.

That is, the rubber composition of the present invention has an extract (E) defined below.
Satisfies the formula (1).

E> 1.2 (A-38) (1) E: 100 parts of vulcanized rubber after extraction with acetone / chloroform
Part by weight of the acetone-chloroform extract relative to parts by weight A: 100 parts of the vulcanized rubber after extraction with acetone-chloroform
Sum of carbon black part by weight and 1/2 silica part by weight relative to parts by weight. Here, the acetone chloroform extraction method, the polymer and the amount of carbon are measured according to JIS K6350. The amount of silica is measured according to the method of JIS K6220. When the above formula (1) is not satisfied, the improvement on the on-ice performance is insufficient, as is clear from the formulation No. 9 described later.

In the present invention, the pulverized product of the plant is further added in an amount of 3 to 50 per 100 parts by weight of the rubber component after extraction of the vulcanized rubber with acetone and chloroform.
Use parts by weight. Examples of the pulverized product include sawdust, walnut shells, corks, peanut shells, ginnan shells, straw, and chaff. The preferred average particle size of the pulverized product is 0.02
~ 1 mm. If the particle size is less than 0.01 mm, the effect is small, 5 mm
If it exceeds the range, the pulverized product is likely to fall off from the vulcanized rubber and the desired effect cannot be obtained.

In the present invention, the pulverized product having a large particle size as described above has little reinforcing effect on rubber, and when the pulverized product having a large particle size is mixed with soft rubber, the hardness of the rubber as a whole is increased, and the performance on snow is good. In addition, since the action of restraining the rubber of the pulverized material is low, it is in a microscopically soft state, and accordingly, it has a microscopically good grounding property and a good performance on ice. Ice such as ice burn contains bubbles of about 0.01 to 0.1 mm,
If a crushed product of 0.01 to 5 mm sticks out from the surface of the treaded rubber, when the tire passes over the ice, the presence of air bubbles will destroy the thin ice portion, which will cause a trap and a great braking effect on ice. Presumed to be done. In addition to the above effects, the pulverized product also has the effect of adsorbing water on the ice plate, and improvement is recognized.

In the present invention, in addition to the above components, known vulcanizing agents, vulcanization accelerators, vulcanization accelerating aids, vulcanization retarders, organic peroxides, reinforcing agents, fillers, antioxidants, tackifiers, Of course, a colorant or the like can be added.

The rubber composition of the present invention can be obtained by kneading the above components with a conventional processing device such as a roll, a Banbury mixer or a kneader.

The rubber composition of the present invention is suitably used for tires used in a ground pressure range of ³ to 15 kg / cm ² , for example, tires for trucks, buses, light trucks, and ultralight trucks. In particular, under the ground contact pressure condition of 6 to 15 kg / cm ² , the rubber obtained from the rubber composition of the present invention has an effect of slipping into the ice plate, the frictional force is increased, and the snow performance is also improved.

(Effects of the Invention) The rubber composition of the present invention has excellent low-temperature properties and is particularly suitable for use in icy roads and snowy roads.

(Examples) Examples and comparative examples will be described below. Incidentally, "parts" means "parts by weight".

Examples and Comparative Examples 100 parts of rubber listed in Table 1, parts of carbon black N220, parts of silica, parts of naphthene oil, 3 parts of zinc white, 3 parts of stearic acid, antioxidant (Santoflex 13) 1
Parts, 1 part of paraffin wax, 1.0 part of vulcanization accelerator (CBS) and 2 parts of sulfur were sufficiently kneaded for 4 minutes with a Banbury mixer to obtain a rubber composition.

Using this rubber composition, a pneumatic all-weather tire 650R16 10PR having a radial structure was produced, and hardness, performance on ice, and performance on snow were measured. Hardness according to ASTM D2228-
The value at 5 ° C. was measured. Performance on ice and snow is -8 ℃
According to actual vehicle tests on the ice ban and on snow. In all cases, the reciprocal of the stopping distance when braking suddenly when running at a speed of 40 km / h is shown as an index with the tire of compound No. 3 as 100, and the larger the value, the better. . The results are shown in Table 1. In addition, formulation Nos. 4 to 6 are examples, and others are comparative examples.

From Table 1, the formulations Nos. 4 to 6 of the examples are excellent in the performance on ice and the performance on snow. However, the compound Nos. 1 and 2 which do not contain the pulverized plant and the compound No. 3 which does not satisfy the formula (1) are inferior in the performance on snow, while the particle size or the compounding amount used the filler out of the range of the present invention. Formulation Nos. 7 to 8 do not sufficiently improve the performance on ice or the performance on snow. Further, even if the crushed plant is properly mixed, the compound No. 9 which does not satisfy the formula (1) does not sufficiently improve the performance on ice.

Claims (2)

[Claims] 1. A tread rubber composition for tires, wherein a diene rubber is blended with at least one of silica and carbon black, wherein an extract (E) defined below satisfies the formula (1) and has an average particle size. A rubber component obtained by extracting the vulcanized rubber with a diameter of 0.01-5 mm from the following vulcanized rubber with acetone-chloroform.
A tread rubber composition for tires, which is used in an amount of 3 to 50 parts by weight based on 100 parts by weight. E> 1.2 (A-38) (1) E: 100 parts of vulcanized rubber after extraction with acetone / chloroform
Part by weight of the acetone-chloroform extract relative to parts by weight A: 100 parts of the vulcanized rubber after extraction with acetone-chloroform
Half of carbon black parts and silica parts by weight to parts by weight 2. The tread rubber composition for a tire according to claim 1, which is used for a tire having a ground pressure of 3 to 15 kg / cm ² .