JP2006089612A - Rubber composition and tire produced by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition resistant to the deterioration with ozone for a long period and exhibiting suppressed discoloration with wax, etc., and provide a tire produced by using the composition. <P>SOLUTION: The rubber composition contains 100 pts. wt. of a diene rubber, 0.5-4 pts. wt. of a paraffin wax and 0.1-100 pts. wt. (based on 100 pts. wt. of the paraffin wax) of a gelling agent. The invention further provides a tire produced by using the rubber composition as the tread or sidewall of the tire. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber composition and a tire using the same, and more particularly to a rubber composition in which deterioration due to ozone and discoloration due to wax or the like are suppressed and a tire using the same.

  It is known that rubber products such as tires are degraded by the action of ozone in the atmosphere, sunlight, etc., and cracks are generated. As a method for solving this problem, a wax is compounded (see Patent Documents 1 to 5). Currently, rubber products are produced by vulcanizing a rubber composition blended with a wax according to this method. Yes.

  The reason why the generation of cracks is prevented by the wax is that the wax blooms out of the rubber product, and a thin film of wax is formed on the surface of the rubber product. This thin film blocks the rubber product from ozone. It is considered to be.

  However, when the wax finishes blooming on the surface, a thin film made of wax is not formed, and deterioration of the rubber product due to ozone cannot be suppressed.

  Therefore, there is currently a demand for a rubber composition that can form a thin film with wax over a long period of time.

  In response to the above requirements, for example, a method of blending a large amount of wax into the rubber composition is also known, but although the generation of cracks is suppressed, the thin film formed of a large amount of wax is used to form the rubber composition. In addition to the surface of the obtained rubber product changing to white, the anti-aging agent blooms on the surface together with the wax, so that the surface of the rubber product changes to brown.

JP-A 63-145346 JP 63-162738 A Japanese Patent Laid-Open No. 1-230648 JP-A-4-202474 JP-A-5-43744

  An object of this invention is to provide the rubber composition which prevented deterioration by ozone for a long period of time, and suppressed discoloration by wax etc., and a tire using the same.

  The present invention contains 0.5 to 4 parts by weight of a paraffin wax with respect to 100 parts by weight of a diene rubber, and 0.1 to 100 parts by weight of a gelling agent with respect to 100 parts by weight of the paraffin wax. The present invention relates to a rubber composition.

  The rubber composition preferably further contains a fatty acid.

  The gelling agent is preferably made of aluminum 2-ethylhexanoate.

  The present invention relates to a tire using the rubber composition as a tread or a sidewall.

  According to the present invention, a paraffin wax and a gelling agent are blended with a diene rubber to gel the paraffin wax, and by adjusting the elution rate of the wax to the rubber surface, the resistance to ozone deterioration, etc. It is possible to provide a rubber composition that greatly improves the anti-aging property and further suppresses discoloration due to wax or the like and a tire using the rubber composition.

  The rubber composition of the present invention comprises a diene rubber component, a paraffin wax and a gelling agent.

  Examples of the diene rubber component in the present invention include unsaturated rubbers such as natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), and acrylonitrile butadiene rubber (NBR). . Of these, natural rubber, butadiene rubber, and styrene-butadiene rubber are preferably used, and particularly natural rubber and butadiene rubber are preferably mixed and used.

  The paraffinic wax refers to a petroleum-derived wax mainly composed of linear hydrocarbons. Other waxes include biologically derived waxes, but since the gelling effect is great, the rubber composition of the present invention uses paraffinic wax.

  The content of the paraffin wax is 0.5 parts by weight or more, preferably 1 part by weight or more with respect to 100 parts by weight of the diene rubber component. When the content of the paraffin wax is less than 0.5 parts by weight, deterioration of the rubber composition due to ozone cannot be prevented. The content of the paraffin wax is 4 parts by weight or less, preferably 3 parts by weight or less. If the content of the paraffin wax exceeds 4 parts by weight, the paraffin wax excessively blooms on the rubber surface, and the resulting rubber composition is discolored.

  The gelling agent in the present invention contains a metal salt. Examples of the metal salt include aluminum stearate, aluminum laurate, aluminum oleate, aluminum behenate, aluminum palmitate, and aluminum 2-ethylhexanoate. Especially, since the gelling effect of a wax is large, it is preferable to use the gelatinizer which consists of aluminum 2-ethylhexanoate as a metal salt.

  The content of the gelling agent is 0.1 parts by weight or more, preferably 0.3 parts by weight or more with respect to 100 parts by weight of paraffinic wax. If the content of the gelling agent is less than 0.1 parts by weight, it is difficult to gel the wax because only a small amount of the gelling agent is blended, and the deterioration of the rubber composition due to ozone is prevented for a long time. I can't. The content of the gelling agent is 100 parts by weight or less, preferably 50 parts by weight or less. When the content of the gelling agent exceeds 100 parts by weight, the excessive gelling agent inhibits wax bloom, so that it is impossible to prevent deterioration of the rubber composition due to ozone.

  Fatty acid can be mix | blended with the rubber composition of this invention. The fatty acid is preferably a saturated and / or unsaturated fatty acid having 8 to 24 carbon atoms. Examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, behenic acid, undecylene acid, oleic acid, linoleic acid, linolenic acid and the like. Above all, it is generally used as a vulcanizing agent for rubber and is easy to obtain. By mixing stearic acid as a fatty acid with a gelling agent, the gelation of paraffinic oil by the gelling agent is promoted. Can do.

  The compounding amount of the fatty acid is preferably 0.1 parts by weight or more, and more preferably 0.3 parts by weight or more with respect to 100 parts by weight of the gelling agent. If the amount of the fatty acid is less than 0.1 parts by weight, the paraffin wax does not sufficiently gel. Further, the blending amount of the fatty acid is preferably 10 parts by weight or less, and more preferably 5 parts by weight or less. If the blending amount exceeds 10 parts by weight, the slipping occurs, and thus there is a tendency that sufficient kneading becomes difficult at the time of kneading.

  In addition to the diene rubber component, paraffin wax, gelling agent, and fatty acid, the rubber composition of the present invention includes an antioxidant, a filler such as carbon black, a softening agent such as oil, zinc oxide, and sulfur. Compounding agents such as a vulcanizing agent and a vulcanization accelerator can be blended as necessary.

  The rubber composition of the present invention is preferably used as a tread or a sidewall among tire members because it is exposed on the tire surface and an excellent effect is obtained.

  The tire of the present invention is preferably produced by an ordinary method using the rubber composition of the present invention as a tread or sidewall tire member. That is, the diene rubber component, paraffin wax, gelling agent, stearic acid, anti-aging agent, and, if necessary, the compounding agent are kneaded by a kneader such as a Banbury mixer or an open roll, and the kneaded product is a tire molding machine. The tire can be manufactured by forming the tire into a tread or sidewall shape and bonding them with other tire members to vulcanize the tire shape.

  The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

The various chemicals used in the examples are described in detail below.
Natural rubber: RSS # 3 manufactured by Tech Bee Hang
Butadiene rubber: UBEPOL-BR150B manufactured by Ube Industries, Ltd.
Carbon Black: Showa Black N330 manufactured by Showa Cabot Corporation
Oil: Idemitsu Kosan Co., Ltd. Dyna Process Oil PS323
Wax: Sunnock wax anti-aging agent manufactured by Ouchi Shinsei Chemical Industry Co., Ltd .: NOCRACK 6C (N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shin Chemical Co., Ltd. )
Stearic acid: Zinc stearate manufactured by Nippon Oil & Fats Co., Ltd .: Zinc Hana No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Gelator: Octopium Aluminum A manufactured by Hope Pharmaceutical Co., Ltd. Gelling agent)
Sulfur: Powder sulfur vulcanization accelerator manufactured by Tsurumi Chemical Industry Co., Ltd .: Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

Examples 1-2 and Comparative Examples 1-3
<Production of rubber sheet for test>
The contents of Table 1 excluding sulfur and vulcanization accelerator were kneaded with a Banbury mixer, and then sulfur and vulcanization accelerator were added to the obtained kneaded product and kneaded with an open roll. Furthermore, the obtained kneaded material was vulcanized to prepare a test rubber sheet.

  The following tests were conducted using the obtained rubber sheet for testing.

<Test>
(Ozone degradation resistance)
A test rubber sheet piece is held in an extension holder and installed in an ozone weatherometer, and a dynamic test is performed for 24 hours and 48 hours under conditions of an ozone concentration of 50 ppm, a temperature of 40 degrees, and an extension ratio of 20%, respectively. After that, the amount of cracks generated was visually evaluated. ◎ if no cracks occurred, ○ if fine cracks were observed, ○ if cracks with a length of 1 mm or less occurred △ if cracks longer than 1 mm occurred × It was.

(Appearance)
The surface of the rubber sheet piece for test was visually observed, and the case where the surface state of the rubber composition appeared black was indicated as ◯, the case where the surface of the rubber composition appeared slightly white or brown was indicated as Δ, and the case where it appeared white or brown was indicated as X.

  The test results are shown in Table 1.

  In Examples 1 and 2, the rubber sheet containing the gelling agent and the paraffinic wax in the amounts specified in the claims does not generate cracks even when exposed to an ozone environment for a long time, and changes in the appearance are seen. It was good.

  In Comparative Example 1, a rubber sheet containing no gelling agent was exposed to an ozone environment for 48 hours, resulting in smaller cracks in ozone degradation.

  In Comparative Example 2, a small crack was generated when the rubber sheet containing a large amount of the gelling agent was exposed to an ozone environment for 24 hours, and a crack exceeding 1 mm was generated when exposed to 48 hours. This is considered to be caused by an excessive gelling agent inhibiting wax bloom.

  In Comparative Example 3, the rubber sheet containing a large amount of paraffinic wax was good against ozone deterioration, but excessive wax bloomed on the rubber surface and turned white.

Claims (4)

For 100 parts by weight of diene rubber,
0.5-4 parts by weight of paraffin wax, and 100 parts by weight of paraffin wax,
A rubber composition containing 0.1 to 100 parts by weight of a gelling agent. Furthermore, the rubber composition of Claim 1 containing a fatty acid. The rubber composition according to claim 1 or 2, wherein the gelling agent comprises aluminum 2-ethylhexanoate. A tire using the rubber composition according to claim 1, 2 or 3 as a tread or a sidewall.