JPS6060002A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To enhance the reinforce ability and workability of a pneumatic tire, by blending specific weight parts of calcium carbonate group compound pigment having a certain BET specific area and an oil absorbing capacity of linseed oil, in at least a part of a rubber material with which the pneumatic tire is formed. CONSTITUTION:A rubber compound blended with 5 to 10wt% of calcium carbonate group compound pigment having more than 60m<2>/g of BET specific area and more than 70ml/100g of oil absorbing capacity of linseed oil, with respect to 100pts.wt. of a natural or synthetic rubber, is used in at lease one part of a tire forming rubber material. In this case, the above-mentioned synthetic rubber may be rubbers used for tires, such as, for example, styrene-butadiene rubber, etc. Further the compound pigment is, for example, such that 0.01 to 0.02mum dia. ultrafine particles are one-dimentionally bound in a chain-like form by a length of 0.05 to 1.00mum. With this arrangement, the reinforce ability and workability of the tire may be enhanced and the cost thereof may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to pneumatic tires, and more particularly to rubber materials constituting the tire, including tread rubber, sidewall rubber, carcass ply coating rubber, and squeegee parts. - Processability and physical properties are improved by blending a calcium carbonate-based composite pigment into at least a portion of the rubber, cushion rubber, inner liner rubber, etc. - This relates to a pneumatic tire using a rubber composition. .

Conventional technology Fine particles of silicic acid and silicates have been called white carbon because they have reinforcing properties second only to carbon black, and rubber materials containing white carbon have been used as white sidewalls in the tire manufacturing industry. In order to satisfy requirements such as adhesion between cords and rubber, cut resistance, and chipping resistance, large tires for rough roads are known in which the tread is formed from a rubber composition that is especially blended with carbon black.

However, the silanol groups on the particle surface of white carbon have the property of absorbing polar substances as well as being hygroscopic, so in rubbers containing white carbon, the white carbon may form adsorption bonds with the rubber, or Due to the cohesive force of white carbon, they coagulate with each other, resulting in high viscosity when unvulcanized, which significantly impairs processability in kneading, extrusion, etc., and has poor dispersion, making it unsatisfactory as a tire rubber material. It is not something that flows. For this reason, by adding polar substances such as organic bases and alcohols, so-called activators, to the white carbon compound rubber, adsorption of silanol groups can be prevented in advance.
Methods have been proposed to suppress the increase in viscosity and improve processability, but these activators have the disadvantage of deteriorating the physical properties after vulcanization, especially the heat build-up. The reality is that it is hardly used in tires.

On the other hand, calcium carbonate is known as a white filler other than white carbon, and has a particle size of 0.08 to 0-5 μm.
sBET fine cubic synthetic products with a specific surface area of 6-50 Tn2/9 and a particle size of 2-10 pm.

There is an amorphous heavy product with a BET specific surface area of 065 to 4 m Q/9, but its reinforcing properties are significantly inferior to that of white carbon, so it has not been used much in the tire manufacturing industry other than as a filler. .

Disclosure of the invention Accordingly, a BET specific surface area of 60 m27g or more and a
Calcium carbonate-based composite pigments with linseed oil absorption of GINHE 009 or higher have extremely excellent reinforcing properties, and by blending them in a specific amount, a rubber composition with excellent processability as a rubber material can be obtained and is inexpensive. Therefore, it was confirmed that by using a rubber material blended with such a calcium carbonate-based composite pigment, a pneumatic tire having characteristics equivalent to or better than conventional pneumatic tires could be obtained more easily and at a lower cost. I have achieved this goal.

Therefore, in the pneumatic tire of the present invention, at least a portion of the rubber material constituting the tire has a BE'T of 6 om'/g or more based on 100 parts by weight of natural rubber and/or synthetic rubber.
The present invention is characterized by using a rubber composition containing 5 to 10 parts by weight of a calcium carbonate-based composite pigment having a specific surface area and a linseed oil absorption amount of 70''/loog or more.

As mentioned above, the pneumatic tire of the present invention includes at least a portion of the rubber material constituting the tire, that is, the tread rubber,
Any one of sidewall rubber, carcass ply coating rubber, squeegee rubber for each part, cushion rubber for each part, inner liner rubber, etc., or a rubber in which the rubber material of the entire tire is blended with the specified amount of calcium carbonate-based composite pigment. The rubber component used in this case is natural rubber and/or synthetic rubber, and the synthetic rubber may be any rubber conventionally used in tires, such as styrene-butadiene rubber, synthetic rubber, etc. These include polyisoprene rubber, polybutadiene rubber, ethylene propylene rubber, butyl rubber, etc., and these can be used alone or in a blend. Further, these synthetic rubbers may be used in a blend with natural rubber.

The calcium carbonate-based composite pigment used in the present invention has a BET specific surface area of at least 79, preferably at least 70 m//l, and at least 70'/1ook, preferably at least 100 m//loog, more preferably at least 100 m//loog. i
It has a linseed oil absorption amount of 20'/1009 or more. This composite pigment has a diameter of 0°01~0.02)
Ultrafine particles of pm are linearly bonded in a chain with a length of 0.05 to 1.00 μm, and within this range, suitable reinforcing properties are exhibited. The method for producing such a composite pigment is to add 1 mole of calcium hydroxide to a water-soluble metal salt that forms a colloidal metal oxide, such as a water bath solution of sulfate or acetate of zinc, or a mixture of these and sulfuric acid, acetic acid, etc. 0.02-0.10 for
Carbonation rate in molar proportion (caao3 weight 10a (OH)
, fjil Furthermore, when the carbonation rate reaches 80%, soluble silicic acid, such as an alkali silicate, such as sodium silicate or silicate sol, is added as required to continue the carbonation reaction. .01~0.02μm
x A calcium carbonate pigment complexed with silicic acid and/or zinc in a chain having a length of 0.05 to 1.00 pm is obtained. By treating with soluble silicic acid, calcium silicate particles exhibit the effect of being more easily dispersed in the rubber while remaining in the form of fine primary particles due to their non-agglomerating properties.
Zinc is also necessary to obtain the desired chain-like particles.

In the present invention, the calcium carbonate pigment is
00 parts by weight, preferably 5 to 100 parts by weight, particularly 5 to 30 parts by weight for tire treads.

If the pigment is less than 5 parts by weight, cut resistance and durability will be affected when used in tire treads.

The chipping property is not improved and is unfavorable, while 100
Exceeding the heavy background area is not preferable because the reinforcing property is rather reduced and the heat generation property is also worsened.

In the present invention, in addition to the above-mentioned calcium carbonate pigments, inorganic pigments and organic pigments such as carbon black, clay, heavy calcium carbonate, light calcium carbonate, or white carbon as required are further blended, and in particular, the calcium carbonate In the case of tire treads made from rubber compositions containing pigments, carbon black is particularly preferably used, with a specific surface area (N, SA) of 80 to 120 determined by nitrogen adsorption method.
m"7g, diphthyl phthalate) (DBP) It is preferable to use highly reinforcing carbon black with an oil absorption of 9o to 1ao"/1oo9! □゛・ku, usually 20~
80 parts by weight is blended. If it is less than 20 parts by weight, no reinforcing effect can be obtained, and if it exceeds 80 parts by weight, the heat generation properties will deteriorate, which is not preferable.

In the present invention, the rubber composition in which the calcium carbonate-based composite pigment is blended includes vulcanizing agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents, softeners, etc. that are usually blended in rubber compositions for tires. The following compounding agents are appropriately blended within the usual blending range and used as a rubber additive for tires.

Examples of the invention The present invention will be explained in detail below with reference to Examples.

Example 1 Four types of rubber compositions with Nα1 to 4 were prepared by kneading the components according to the formulation contents (parts by weight) shown in Table 1, and the Mooney viscosity of these rubber compositions was measured. Furthermore, after vulcanizing these rubber compositions in a press at 145°C for 40 minutes, the tensile strength, elongation, and modulus were measured. The impact resistance cut test and tread appearance test were also evaluated.

・The obtained results are also listed in Table 1.

The evaluation methods for the impact resistance cut test and tread appearance test are as follows.

Impact resistance cut test The rubber composition after vulcanization was tested with a pendulum type impact cut tester.
A steel blade is struck from a certain height to create a scratch, and the depth of the cut is indicated.

Tread appearance test A bias structure pneumatic tire for trucks, buses, etc. of size 1000-20, 14 ply was prepared by dividing the tread into four parts and using the rubber composition shown in Table 1. 200 while frequently applying sudden brakes on the road.
After running 0 km, the number of large cuts (scratches with a depth of 0 + m or more) and small cuts (with a depth of 1 to 100 m) per 100 cm2 of tread surface
5. The number of scratches in the groove) and the number of chippings (a phenomenon in which small pieces of rubber of 25 ml or more are scraped off) were evaluated.

Table 1 *5: H-(i,a dimethyl-butyl)-N'-phenyl-p-phenylenediamine, manufactured by Mitsubishi Monsando Kasei Co., Ltd., product name/Example 2 Contents shown in Table 2 (parts by weight) Then, the respective compounded components were kneaded to make four types of rubber compositions with Na 5 to 8, and the performance of these rubber compositions was evaluated in the same manner as in Example 1, and the obtained results are also listed in Table 2. .

Table 2/Example 3 Four types of rubber compositions, N[19 to 12, were prepared by kneading the respective compounded components with the compounding contents (TLffi part) shown in Table 8, and these rubber i compositions were kneaded. Tire size 1 each
05-3R14 radial tie for passenger cars.

After curing the tire, the tensile strength, elongation, and modulus were evaluated, and the results are shown in Table 8.

Table 8 Effects of the Invention The tire of the present invention is made of a rubber material comprising a rubber composition in which a specific amount of the calcium carbonate composite pigment is blended with natural rubber and/or synthetic rubber. By configuring at least a part of The rubber composition used in 1. contains conventional calcium carbonate.・It is clear that the reinforcing property is significantly superior to that of rubber compositions containing white carbon, and the workability is significantly superior to that of rubber compositions containing white carbon. Tires with rubber have improved running performance on rough roads due to improved rubber reinforcement, and tires with sidewalls made of the above-mentioned materials have the advantage of being advantageous for use with brightly colored sidewalls.

Claims (1)

[Claims] L At least a part of the rubber material constituting the tire contains e based on 100 parts by weight of natural rubber and/or synthetic rubber.
BET specific surface area of om/9 or more and 70”/xo
1. A pneumatic tire characterized by using a rubber composition comprising 5 to 10 parts by weight of a calcium carbonate-based composite pigment having a linseed oil absorption amount of OP or more.