JP2006219583A - Rubber composition for tire and tire comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for a tire, enabling the production of tire having excellent gripping properties of the tire and steering stability of a car; and to provide the tire comprising the rubber composition. <P>SOLUTION: The rubber composition for the tire contains 0.1-30 pts.wt. polymer having an oxazoline group represented by chemical formula (I) based on 100 pts.wt. rubber component. The tire comprises the rubber composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber composition for a tire that enables production of a tire with improved grip performance and steering stability, and a tire using the same.

  In recent years, awareness of safety has been increasing with the improvement of motor performance and high horsepower, and the development of highways. In particular, grip performance represented by acceleration performance and brake performance is an important required characteristic.

  Conventionally, as a technique for improving grip performance, a method of improving the glass transition point of a rubber composition obtained by using a styrene butadiene rubber having an increased amount of styrene and vinyl as a rubber component is known. . However, in this case, there has been a problem that the wear resistance is lowered or the grip performance of the tire is lowered at a low temperature, and the tire becomes brittle and broken.

  In addition, a method of blending a large amount of a softener such as oil is well known. However, there is a problem that wear resistance is lowered.

  As a method for improving both grip performance and wear resistance, a method using a large amount of fine carbon black is also known. However, if an excessive amount of carbon black is used, poor dispersion of the carbon black occurs. On the contrary, there is a problem that the wear resistance is lowered.

  In addition, a method of adding an inorganic compound such as tungsten to a rubber composition (see Patent Document 1), a method of adding an acrylic resin (see Patent Document 2), and a method of adding urethane-based particles (see Patent Document 3) However, a tire rubber composition exhibiting sufficient grip performance and steering stability has not been obtained yet.

JP 2000-319447 A JP 2002-80642 A JP 2002-97303 A

  It is an object of the present invention to provide a tire rubber composition and a tire comprising the same, which make it possible to produce a tire excellent in tire grip performance and vehicle handling stability.

  The present invention relates to a chemical formula (I) based on 100 parts by weight of a rubber component.

The rubber composition for tires containing 0.1-30 weight part of polymers which have an oxazoline group shown by these.

  The main chain skeleton of the polymer is preferably a styrene polymer and / or an acrylic polymer.

  Further, the tire rubber composition preferably contains 0.1 to 30 parts by weight of a protonic acid and / or a phenol derivative with respect to 100 parts by weight of the rubber component.

  The present invention also relates to a tire comprising the tire rubber composition.

  According to the present invention, by providing a polymer containing an oxazoline group, a tire rubber composition that improves the grip performance of the tire and further exhibits excellent vehicle handling stability, and a tire comprising the same are provided. Can do.

  The rubber composition for tires of the present invention comprises a rubber component and a chemical formula (I)

And a polymer having an oxazoline group (hereinafter referred to as polymer 1).

  Examples of the rubber component include rubber components generally used in the tire industry. Particularly, polyisoprene rubber (IR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber ( Diene-based synthetic rubbers such as CR) and butyl rubber (IIR) are preferred. Among these, SBR is preferable as the rubber component because the grip performance and wear resistance are improved in a balanced manner. These rubber components may be used alone or in combination of two or more.

  When SBR is contained in the rubber component, the SBR content in the rubber component is preferably 50% by weight or more, and more preferably 70% by weight or more. When the content is less than 50% by weight, there is a tendency that sufficient grip performance cannot be obtained. The content of SBR is particularly preferably 100% by weight.

  The weight average molecular weight of the polymer 1 is preferably 2000 or more, and more preferably 5000 or more. When the weight average molecular weight is less than 2000, the polymer 1 blooms from the rubber, and the grip performance and the handling stability tend to be lowered. Moreover, it is preferable that the weight average molecular weight of the polymer 1 is 200000 or less, and it is more preferable that it is 180000 or less. When the weight average molecular weight exceeds 200,000, the dispersion of the polymer 1 in the rubber tends to be poor and the strength tends to be lowered.

  The content of the oxazoline group in the polymer 1 is represented by an oxazoline value (g solid / eq.). The oxazoline value is the weight of the polymer per mole of the oxazoline group, and the greater the oxazoline value, the greater the oxazoline content in the polymer.

  The oxazoline value of the polymer 1 is preferably 100 or more, and more preferably 150 or more. When the oxazoline value is less than 100, the polymer 1 blooms and the grip performance and the handling stability tend to be lowered. Further, the oxazoline value is preferably 5000 or less, and more preferably 3000 or less. When the oxazoline number exceeds 5000, there is a tendency that the effect of improving grip performance and steering stability is not observed.

  Specific examples of the main chain skeleton of the polymer 1 include acrylate, unsaturated nitrile, unsaturated amide, vinyl ester, vinyl ether, α-olefin, halogen-containing α, β-unsaturated aliphatic hydrocarbon, α, Examples thereof include polymers such as β-unsaturated aromatic hydrocarbons. For example, examples of the acrylate polymer include acrylic polymers, and examples of the unsaturated aromatic hydrocarbon polymer include styrene polymers. Of these, styrene polymers and / or acrylic polymers are preferred from the standpoints of productivity, cost, processability, and the like.

  By using the main chain skeleton as a polymer, blooming from the rubber can be suppressed, and excellent effects of preventing a decrease in grip performance and steering stability can be obtained.

  The content of the polymer 1 is 0.1 parts by weight or more, preferably 2 parts by weight or more with respect to 100 parts by weight of the rubber component. If the content is less than 0.1 parts by weight, it is difficult to obtain an effect of improving grip performance. The content of the polymer 1 is 30 parts by weight or less, preferably 20 parts by weight or less. When the content exceeds 30 parts by weight, the wear resistance decreases.

  The tire rubber composition of the present invention preferably further contains a protonic acid and / or a phenol derivative.

  The proton acid is preferably an aliphatic carboxylic acid or an aromatic carboxylic acid.

  Specific examples of the aliphatic carboxylic acid include aliphatic monocarboxylic acids such as acetic acid, propionic acid, and oleic acid, and aliphatic dicarboxylic acids such as oxalic acid and maleic acid.

  Specific examples of the aromatic carboxylic acid include benzoic acid, p-methoxybenzoic acid, p-chlorobenzoic acid, p-nitrobenzoic acid, cinnamic acid, naphthoic acid and other aromatic monocarboxylic acids, and phthalic acid. Examples thereof include aromatic carboxylic acids such as acid, phthalic anhydride, trimellitic acid, and pyromellitic acid.

  As the protonic acid, the interaction with the oxazoline group has the effect of improving the grip performance and the handling stability. Therefore, the aromatic carboxylic acid having a larger interaction is preferable, and the aromatic monocarboxylic acid is more preferable. preferable.

  Specific examples of the phenol derivative include 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 2,2′-methylenebis- (4-methyl-6-tert-butylphenol), 2,2 '-Methylenebis- (4-methyl-6-methylcyclohexylphenol), 4,4'-thiobis- (3-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6) -T-butylphenol), 4,4'-methylene-bis- (2,6-di-t-butylphenol), 2,2'-methylenebis- (6-α-methyl-benzyl-p-cresol), 2, 2'-butylidene-bis- (6-t-butyl-m-cresol), 2,2'-ethylidene-bis- (4,6-di-t-butylphenol), 1,1-bis- (4-hydro Cyphenyl) -cyclohexane, 4,4′-thiobis- (6-tert-butyl-o-cresol), 4,4′-dithiobis- (2,6-di-tert-butylphenol), bis- (3,5- Bisphenol derivatives such as di-t-butyl-4-hydroxybenzyl) sulfide, 2,6-di-t-butyl-4-methylphenol, styrenated phenol, alkylated phenol, cyclohexylated phenol, 1-oxy- 3-methyl-4-isopropylbenzene, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-sec-butylphenol, Butylhydroxyanisole, 2- (1-methylcyclohexyl) -4,6-dimethylphenol, 2,6-di-t-butyl-α- Such monophenol derivatives such as methylamino -p- cresol. Among them, the phenol derivative is preferably a bisphenol derivative because it interacts more effectively with a small amount with respect to the oxazoline group and high grip performance and steering stability can be obtained.

  The phenol derivative can also be used in combination with a protonic acid.

  The content of the protonic acid and / or phenol derivative is preferably 0.1 parts by weight or more, and more preferably 0.5 parts by weight or more with respect to 100 parts by weight of the rubber component. If the content is less than 0.1 parts by weight, the effect of improving the grip performance tends to be difficult to obtain. The content of aromatic carboxylic acid and / or phenol derivative is preferably 30 parts by weight or less, and more preferably 20 parts by weight or less. When the content exceeds 30 parts by weight, the wear resistance tends to decrease.

  The tire rubber composition of the present invention preferably further contains a reinforcing filler such as silica and carbon black in addition to the rubber component, the polymer 1, and the protonic acid and / or phenol derivative. Two or more of these may be used in combination. As the reinforcing filler, it is preferable to mainly contain carbon black.

The nitrogen adsorption specific surface area of carbon black is preferably 80 m ² / g or more, and more preferably 100 m ² / g or more. When the nitrogen adsorption specific surface area is less than 80 m ² / g, both grip performance and wear resistance tend to decrease. Further, the nitrogen adsorption specific surface area of carbon black is preferably 280 m ² / g or less, and more preferably 200 m ² / g or less. When it exceeds 280 m ² / g, it is difficult to obtain a good dispersion of carbon black, and the wear resistance is lowered.

  The content of carbon black is preferably 10 parts by weight or more and more preferably 20 parts by weight or more with respect to 100 parts by weight of the rubber component. When the content is less than 10 parts by weight, the wear resistance tends to decrease. Further, the content of carbon black is preferably 200 parts by weight or less, and more preferably 150 parts by weight or less. When the content exceeds 200 parts by weight, the processability of the rubber composition tends to decrease.

  In addition to the rubber component, the polymer 1, and the protonic acid and / or phenol derivative, and the reinforcing filler, the rubber composition for a tire of the present invention includes a silane coupling agent, a mineral oil as necessary. Normal tire industry such as softeners such as anti-aging agents, vulcanizing agents such as wax and sulfur, various vulcanization accelerators, various softening agents, various anti-aging agents, stearic acid, antioxidants, and ozone degradation inhibitors Additives used in the above can be appropriately blended.

  The tire of the present invention is produced by a usual method using the tire rubber composition of the present invention. That is, the rubber composition for a tire of the present invention containing the rubber component, the polymer 1, and the protonic acid and / or phenol derivative, and, if necessary, the reinforcing filler and additive is added to the tire at an unvulcanized stage. Extrusion processing is performed in accordance with the shape of each member, particularly the tread, and molding is performed by a normal method on a tire molding machine to form an unvulcanized tire. This unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire.

  The tire of the present invention preferably exhibits high grip performance, and is preferably a racing tire that requires particularly high performance.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it cannot be overemphasized that the technical scope of this invention is not limited to these Examples.

Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
SBR: SBR1502 manufactured by JSR Corporation
Carbon black: Show black N220 manufactured by Showa Cabot Co., Ltd. (nitrogen adsorption specific surface area: 125 m ² / g)
Silica: Ultrasil VN3 manufactured by Degussa (nitrogen adsorption specific surface area: 210 m ² / g)
Silane coupling agent: Si69 manufactured by Degussa
Compound A: EPOCROS RPS manufactured by Nippon Shokubai Co., Ltd. (main chain skeleton: styrene polymer, weight average molecular weight: 20000, oxazoline number: 220)
Compound B: EPOCROSS WS manufactured by Nippon Shokubai Co., Ltd. (main chain skeleton: acrylic polymer, weight average molecular weight: 160000, oxazoline number: 3700)
Protonic acid: Benzoic acid aging inhibitor: Nocrack 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Stearic acid: Zinc stearate manufactured by Nippon Oil & Fats Co., Ltd .: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powder sulfur vulcanization accelerator manufactured by Tsurumi Chemical Industry Co., Ltd. Noxeller NS made by

Examples 1 to 3 and Comparative Example A chemical other than sulfur and vulcanization accelerator shown in Table 1 was kneaded at 120 ° C. for 5 minutes using a Banbury mixer, and then sulfur and vulcanization accelerator were added. In addition, various test rubber compositions were obtained by kneading at 50 ° C. for 5 minutes using a roll machine.

  The obtained various test rubber compositions were press vulcanized at 170 ° C. for 20 minutes to obtain various vulcanizates, which were used in the following tests.

(Grip performance)
Using a flat belt friction tester (FR5010 type) manufactured by Ueshima Seisakusho, changing the slip ratio of the sample to the road surface from 0 to 70% at a speed of 20 km / h, a load of 4 kgf, and an outside air temperature of 30 ° C. Among the friction coefficients detected at that time, the maximum value was read. And the value of the comparative example was set to 100, and the other values were each displayed as an index. In addition, as a sample, what shape | molded the said vulcanizate in the cylinder shape of width 20m and diameter 100mm is used.

(Steering stability)
A tire of 215/45 R17 size having a tread made of the vulcanizate was produced, and an actual vehicle was run on a vehicle equipped with the tire on a test course on an asphalt road surface. The test driver evaluated the stability of the steering control at that time. The evaluation is performed with a maximum score of 5. The larger the value, the better the steering stability (5; good, 4; somewhat good, 3; normal, 2; somewhat bad, 1; bad).

  The test results are shown in Table 1.

Claims (4)

For 100 parts by weight of rubber component,
Chemical formula (I)

A rubber composition for tires containing 0.1 to 30 parts by weight of a polymer having an oxazoline group represented by the formula: The tire rubber composition according to claim 1, wherein the main chain skeleton of the polymer is a styrene polymer and / or an acrylic polymer. Furthermore, the rubber composition for tires of Claim 1 or 2 which contains 0.1-30 weight part of proton acids and / or a phenol derivative with respect to 100 weight part of rubber components. A tire comprising the rubber composition for a tire according to claim 1, 2 or 3.