JP2012149159A - Rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition having a crosslinking degree improved by improving dispersibility of zinc flower, and thus providing a tire obtained from the rubber composition, and having improved mechanical characteristics and heat build-up, and to provide the tire.SOLUTION: The rubber composition contains 1-10 pts.mass of a surface-treated zinc flower surface-treated with an organosilane compound based on 100 pts.mass of a diene rubber.

Description

  The present invention relates to a rubber composition used for a tire and a tire manufactured using the rubber composition.

  Zinc white is widely used in rubber compositions as a vulcanization accelerating aid, but it is difficult to obtain good dispersibility in the rubber composition because of its strong cohesiveness.

  In order to improve the dispersibility of zinc white in the rubber composition, for example, Patent Document 1 discloses the use of high specific surface area zinc oxide. Patent Document 2 discloses the use of specific styrene butadiene rubber (SBR) and activated zinc oxide. Furthermore, Patent Document 3 discloses the use of a wet master badge in which a slurry solution is prepared in advance from a specific filler and zinc white and then mixed with a rubber solution.

  However, these conventional techniques still have a problem that sufficient dispersibility has not yet been obtained, a complicated process and a problem in cost.

  On the other hand, Patent Documents 4 and 5 describe a method for producing zinc white surface-treated with an organic silane for improving dispersibility, usage examples, and the like, for example, application to a resin composition. No mention is made of application to rubber compositions.

  The present inventor has found that the surface-treated zinc white exhibits good dispersibility under certain conditions even in the rubber composition, and has completed the present invention based on this finding.

Japanese Patent Laid-Open No. 2002-265673 JP 2008-19334 A JP 2006-213791 A JP-A-8-59890 JP-A-7-232919

  The present invention improves the degree of cross-linking by improving the dispersibility of zinc white in the rubber composition, and thus the rubber composition capable of improving the mechanical properties and heat buildup of the tire obtained from the rubber composition. An object of the present invention is to provide a tire having improved mechanical characteristics and heat generation.

  The tire rubber composition of the present invention contains 1 to 10 parts by mass of a surface-treated zinc white surface-treated with an organosilane compound with respect to 100 parts by mass of a diene rubber in order to solve the above problems. To do.

  In the above, it is preferable that the treatment amount of the organosilane compound in the surface-treated zinc white is 0.1 to 5% by mass with respect to zinc.

  The pneumatic tire of this invention shall be produced using the said rubber composition of this invention.

  According to the present invention, by using surface-treated zinc white instead of ordinary zinc white, the dispersibility of zinc white in the rubber composition can be improved and the degree of crosslinking can be improved. As a result, a tire with improved mechanical properties and low heat build-up can be obtained using the rubber composition.

  Hereinafter, matters related to the implementation of the present invention will be described in detail.

  As described above, the tire rubber composition of the present invention is characterized by using a predetermined amount of surface-treated zinc white surface-treated with an organosilane compound instead of ordinary zinc white.

  Examples of the organic silane compound include 3-aminopropyltrimethoxysilane, 3-aminoproprotriethoxysilane, 3- (2-aminoethyl) -aminopropyltrimethoxysilane, and 3- (2-aminoethyl) aminopropyl. Methyldimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane 3-glycidoxypropyltriethoxysilane, bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, vinyltriacetoxysilane, vinyltris (methoxyethoxy) silane, Bi Rutrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercapropropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3 -Methacryloxypropylmethyldimethoxysilane and the like. Of these, 3-aminopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like are preferable.

  In these organosilane compounds, silanol groups generated by hydrolysis of hydrolyzable groups react with hydroxyl groups on the surface of zinc oxide, while organic functional groups such as amino groups, epoxy groups, vinyl groups, methacryloxy groups, etc. Is considered to contribute to the improvement of the dispersibility of zinc white by reacting with the rubber component.

  The treatment amount of the organosilane compound in the surface-treated zinc white is preferably 0.1 to 5% by mass, more preferably 0.5 to 2.5% by mass with respect to zinc. If it is less than 0.1% by mass, it is difficult to obtain a desired effect of improving dispersibility. On the other hand, when the content exceeds 5% by mass, a tendency for the dispersibility to decrease is recognized.

  These surface-treated zinc white can use what is marketed, and can also be manufactured by a well-known method. As a treatment method, for example, an aqueous zinc slurry is prepared, and an organosilane compound is dropped into the slurry, stirred, filtered, washed, and dried by heating.

  Moreover, 1-10 mass parts is preferable with respect to 100 mass parts of diene rubbers, and, as for content of the said surface treatment zinc white, 2-8 mass parts is more preferable. If it is less than 1 part by mass, it is difficult to obtain a desired vulcanization acceleration effect. On the other hand, when it exceeds 10 mass parts, the tendency for a crosslinking degree, intensity | strength, low exothermic property, etc. to get worse is recognized.

  In the rubber composition according to the present invention, a composition according to a conventional diene rubber composition for tires can be adopted except that the surface-treated zinc white is used.

  Examples of the diene rubber that can be used in the present invention include various natural rubbers (NR), various polyisoprene rubbers (IR), various styrene butadiene rubbers (SBR), various polybutadiene rubbers (BR), etc. 1 type may be used and it may be used in combination of 2 or more types. Preferably, either natural rubber or isoprene rubber is used, or these are used in combination.

  As the filler, a reinforcing filler made of at least one of carbon black and silica can be used.

  Examples of silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Among these, wet silica is preferable.

  The content of these reinforcing fillers is preferably 30 to 150 parts by mass and more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the diene rubber.

  In addition, when mix | blending a silica, it is preferable to mix | blend silane coupling agents, such as sulfide silane and mercaptosilane. It is preferable that the compounding quantity of a silane coupling agent is 5-15 mass parts with respect to 100 mass parts of silica.

  The rubber composition according to the present invention includes various additives generally used in tire rubber compositions such as stearic acid, anti-aging agents, waxes, vulcanizing agents, and vulcanization accelerators in addition to the above components. Can be blended.

  Examples of the vulcanizing agent include sulfur and sulfur-containing compounds, and are not particularly limited. However, the blending amount is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is 0.5-5 mass parts. Moreover, as a compounding quantity of a vulcanization accelerator, it is preferable that it is 0.1-7 mass parts with respect to 100 mass parts of said rubber components, More preferably, it is 0.5-5 mass parts.

  The rubber composition of the present invention is prepared by kneading according to a conventional method using a rubber kneader such as a normal Banbury mixer or kneader.

  The rubber composition comprising the above can be used as a tread rubber or a sidewall rubber of a tire, and the tire is formed by vulcanizing the rubber composition according to a conventional method, for example, at 140 to 180 ° C. Can do.

  The pneumatic tire of the present invention can be produced by a usual method using the tire rubber composition of the present invention.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  Using a Banbury mixer, according to the blending (parts by mass) shown in Table 1 (carbon blending) and Table 2 (silica blending) below, first, in the first mixing stage, components other than sulfur and vulcanization accelerator are added and mixed Then, sulfur and a vulcanization accelerator were added and mixed to the obtained mixture in the final mixing stage to prepare a tire rubber composition. The detail of each compound in Table 1 and Table 2 is as follows.

・ NR: Natural rubber (RSS 3)
・ BR: Ube Industries, Ltd. BR150B
-SBR: Bayer VSL5025-2HM (oil 37.5 phr)
・ Carbon black: Product name Dia Black N339 manufactured by Mitsubishi Chemical Corporation
・ Silica: Tosoh Silica Co., Ltd. Product name Nip Seal AQ
-Surface-treated zinc white (1): Product name Zano20 Plus2 manufactured by Umicore (surface treatment with 3-aminopropyltrimethoxysilane represented by the following formula, surface treatment rate 1 mass%)

-Surface-treated zinc white (2): Product name Zano20 Plus3 manufactured by Umicore (surface treatment with 3-methacryloxypropyltrimethoxysilane represented by the following formula, surface treatment rate of 1% by mass)

-Surface treatment zinc white (3): 3-glycidoxypropyltrimethoxysilane-treated zinc white (surface treatment with 3-glycidoxypropyltrimethoxysilane represented by the following formula, surface treatment rate 1 mass%) (known) Surface treatment by the method of)

-Surface treatment zinc white (4): ZOCHEM INC. Product name ZOCO172 (propionic acid surface treatment, surface treatment rate 0.1% by mass)
-Zinc flower: Zinc flower No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd.-Active zinc flower: Product name Zinkoxyd aktiv
・ Organic silane compound: Shin-Etsu Silicone 3-Aminopropyltrimethoxysilane (trade name KBM-903) manufactured by Shin-Etsu Chemical Co., Ltd.
Coupling agent: Si75 manufactured by Degussa
・ Stearic acid: product name LUNAC S20 manufactured by Kao Corporation
Anti-aging agent: Product name Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.
・ Sulfur: Tsurumi Chemical Co., Ltd. 5% oil-filled fine powder sulfur ・ Vulcanization accelerator: Sumitomo Chemical Co., Ltd.

  About each obtained rubber composition, MH (index of a crosslinking degree), breaking strength, and loss factor tan-delta were measured using the test piece of the predetermined shape vulcanized at 150 degreeC for 30 minutes. Each measuring method is as follows. The results are shown in Tables 1 and 2.

-MH: In accordance with JIS K6300-2 (2001), using a disk-type rheometer, the maximum torque (MH) during vulcanization at 150 ° C x 45 minutes was determined, and the value of Comparative Example 1 was taken as 100. displayed. The larger the value, the more vulcanized and the higher the degree of crosslinking.

-Breaking strength: A tensile test (dumbbell shape No. 3) was performed according to K6251 and the breaking strength was measured. Displayed with an index with the value of Comparative Example 1 as 100.

Loss coefficient tan δ (60 ° C.): In accordance with JIS K6394, using a viscoelasticity tester manufactured by Toyo Seiki Co., Ltd., loss coefficient tan δ at a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of 1%, and a temperature of 60 ° C. Was measured and indicated by an index with the value of Comparative Example 1 being 100. It shows that exothermic property is small and favorable, so that a numerical value is small.

  As can be seen from the results shown in Table 1, the rubber compositions of Examples 1 to 4 according to the present invention have a degree of cross-linking, a breaking strength, and a low exothermicity as compared with Comparative Example 1 corresponding to a conventional product. A significant improvement was observed. On the other hand, Comparative Example 2 in which activated zinc white (no surface treatment) was blended, Comparative Example 3 in which zinc white and a surface treatment agent were blended independently, Comparative Example 4 in which more than a prescribed amount of surface-treated zinc white was blended, The comparative example 5 which mix | blended the surface treatment zinc white processed with the processing agents other than an organosilane compound became a result of the substantially comparable level as the comparative example 1. FIG.

  Similarly, in the results shown in Table 2, the rubber compositions of Examples 5 to 7 according to the present invention have a degree of cross-linking, a breaking strength, and a low exothermicity as compared with Comparative Example 6 corresponding to a conventional product. Was noticeably improved.

  The rubber composition of the present invention can be used for various tires such as passenger cars, light trucks, trucks and buses.

Claims (3)

  A rubber composition for tires containing 1 to 10 parts by mass of a surface-treated zinc white surface-treated with an organosilane compound with respect to 100 parts by mass of a diene rubber.   The rubber composition according to claim 1, wherein an amount of the organic silane compound treated in the surface-treated zinc white is 0.1 to 5% by mass with respect to zinc.   A pneumatic tire produced using the rubber composition according to claim 1.