JP2006233177A - Rubber composition and tire having tread using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition capable of producing a tire that improves rolling resistance performance, wet skid performance and driving stability of a vehicle in good balance, and further reduces fuel consumption, and to provide a tire having a tread comprising the rubber composition. <P>SOLUTION: The rubber composition comprises silica (1) having a nitrogen adsorption specific area of not more than 100 m<SP>2</SP>/g and silica (2) having a nitrogen adsorption specific area of at least 180 m<SP>2</SP>/g of 30-150 pts.wt. in total based on a 100 pts.wt. of the rubber composition, wherein the contents of silica (1) and silica (2) satisfy the formula: [content of silica (1)]×0.2≤[content of silica (2)]≤[content of silica (1)]×6.5, and the tire has a tread using the rubber composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber composition and a tire having a tread.

  Conventionally, by reducing the rolling resistance of a tire (improving rolling resistance performance), the fuel efficiency of the vehicle has been reduced. In recent years, there has been a strong demand for lower fuel consumption of vehicles, and excellent low heat build-up is required for rubber compositions for producing treads with a high occupation ratio in tires among tire members. Yes.

  As a method of satisfying the low exothermic property of the rubber composition, a method of reducing the blending amount of the reinforcing filler is known. However, since the hardness of the rubber composition is lowered, the tire is softened and the vehicle is handled. There was a problem that the performance (steering stability) and the wet skid performance of the tire deteriorated.

  Patent Document 1 discloses a tire rubber composition containing anhydrous silica and hydrous silica in order to improve wet skid performance. However, there is a problem that the rolling resistance performance is not sufficiently improved.

  As described above, a rubber composition that can produce a tire that improves the rolling resistance performance, wet skid performance, and vehicle handling stability in a well-balanced manner has not been known so far.

JP 2003-192842 A

  The present invention relates to a rubber composition that can improve the rolling resistance performance and wet skid performance as well as the driving stability of a vehicle in a well-balanced manner and that can further reduce fuel consumption, and a tire having a tread using the rubber composition. The purpose is to provide.

In the present invention, a total of 30 to 150 weight percent of (1) silica having a nitrogen adsorption specific surface area of 100 m ² / g or less and (2) silica having a nitrogen adsorption specific surface area of 180 m ² / g or more with respect to 100 parts by weight of the rubber component. It is related with the rubber composition in which the content of silica (1) and (2) satisfies the following formula.
[Content of silica (1)] × 0.2 ≦ [Content of silica (2)]
≦ [Content of silica (1)] × 6.5

The rubber composition has the general formula-(R-S _x ) _n-
(Wherein, R is _{(CH 2 -CH 2 -O) m} -CH 2 -CH 2, x is an integer of 3 to 6, n represents an integer of 10 to 400, m is an integer of 2-5 .)
It is preferable to contain 0.5 to 30 parts by weight of an organic vulcanizing agent satisfying the above.

  The present invention relates to a tire having a tread using the rubber composition.

  According to the present invention, silica having a low nitrogen adsorption specific surface area and silica having a high nitrogen adsorption specific surface area are blended, and the mixing ratio of the contents of the two types of silica is set within a predetermined range, whereby rolling resistance performance and It is possible to provide a rubber composition capable of producing a tire capable of improving wet skid performance and driving stability in a well-balanced manner and further reducing fuel consumption, and a tire having a tread using the rubber composition.

The rubber composition of the present invention comprises a rubber component, (1) silica having a nitrogen adsorption specific surface area of 100 m ² / g or less (hereinafter referred to as silica (1)), and (2) a nitrogen adsorption specific surface area of 180 m ² / g. It contains the above silica (hereinafter referred to as silica (2)).

  The rubber component is preferably a diene rubber. Examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR). And styrene-isoprene-butadiene copolymer rubber (SIBR). These diene rubbers may be used alone or in combination of two or more. Among these, SBR is preferable because the rolling resistance performance and the wet skid performance can be improved in a balanced manner.

  Examples of silicas (1) and (2) include silica (anhydrous silicic acid) obtained by a dry method, silica (hydrous silicic acid) obtained by a wet method, and particularly silica obtained by a wet method. It is preferable.

The nitrogen adsorption specific surface area (hereinafter referred to as N ₂ SA) of silica (1) is 100 m ² / g or less, preferably 80 m ² / g or less, more preferably 60 m ² / g or less. When N ₂ SA of silica (1) exceeds 100 m ² / g, the effect obtained by mixing with silica (2) is small. Further, N ₂ SA of silica (1) is preferably 20 m ² / g or more, and more preferably 30 m ² / g or more. When N ₂ SA of silica (1) is less than 20 m ² / g, the breaking strength of the rubber composition tends to be lowered.

  The content of silica (1) is preferably 10 parts by weight or more, more preferably 20 parts by weight or more with respect to 100 parts by weight of the rubber component. When the content of silica (1) is less than 10 parts by weight, the rolling resistance tends not to be sufficiently reduced. Further, the content of silica (1) is preferably 120 parts by weight or less, and more preferably 80 parts by weight or less. When the content of silica (1) exceeds 120 parts by weight, the fracture strength tends to decrease.

N ₂ SA of silica (2) is 180 m ² / g or more, preferably 190 m ² / g or more, more preferably 200 m ² / g or more. When N ₂ SA of silica (2) is less than 180 m ² / g, the effect obtained by mixing with silica (1) is small. Also, N ₂ SA of the silica (2) is preferably from 300 meters ² / g or less, more preferably 240 m ² / g. When N ₂ SA of silica (2) exceeds 300 m ² / g, processability tends to deteriorate.

  The content of silica (2) is preferably 5 parts by weight or more and more preferably 10 parts by weight or more with respect to 100 parts by weight of the rubber component. When the content of silica (2) is less than 5 parts by weight, there is a tendency that sufficient steering stability cannot be obtained. Moreover, 100 weight part or less is preferable and, as for content of a silica (2), 60 weight part or less is more preferable. If the content of silica (2) exceeds 100 parts by weight, processability tends to deteriorate.

  The total content of silica (1) and (2) is 30 parts by weight or more, preferably 40 parts by weight or more, and more preferably 50 parts by weight or more with respect to 100 parts by weight of the rubber component. When the total content of silica (1) and (2) is less than 30 parts by weight, the reinforcing effect due to the addition of silica (1) and (2) cannot be sufficiently obtained. The total content of silica (1) and (2) is 150 parts by weight or less, preferably 120 parts by weight or less, more preferably 100 parts by weight or less. When the total content of silica (1) and (2) exceeds 150 parts by weight, it is difficult to uniformly disperse silica in the rubber composition, and the processability of the rubber composition is deteriorated.

The content of silica (1) and the content of (2) satisfy the following formula.
[Content of silica (1)] × 0.2 ≦ [Content of silica (2)]
≦ [Content of silica (1)] × 6.5

  The content of silica (2) is 0.2 times or more, preferably 0.5 times or more of the content of silica (1). When the content of silica (2) is less than 0.2 times the content of silica (1), the steering stability is lowered. The content of silica (2) is not more than 6.5 times the content of silica (1), preferably not more than 4 times, more preferably not more than 1 time (1 time). When the content of silica (2) is more than 6.5 times the content of silica (1), rolling resistance increases.

  In the present invention, a specific amount of silica (1) and (2) is blended and kneaded with the rubber component, so that the rolling resistance performance and wet skid performance of the tire and the steering stability of the vehicle are all well balanced. It becomes possible to improve.

  The rubber composition of the present invention preferably contains an organic vulcanizing agent in addition to the rubber component and silica (1) and (2).

The organic vulcanizing agent is represented by the following general formula-(R-S _x ) _n-
(Wherein, R is _{(CH 2 -CH 2 -O) m} -CH 2 -CH 2, x is an integer of 3 to 6, n represents an integer of 10 to 400, m is an integer of 2-5 .)
It is a compound that satisfies

  In formula, 3-6 are preferable and 3-5 are more preferable. When x is less than 3, vulcanization tends to be delayed. Moreover, when x exceeds 6, there exists a tendency for manufacture of a rubber composition to become difficult.

  In the formula, n is preferably an integer of 10 to 400, and more preferably an integer of 10 to 300. When n is less than 10, the organic vulcanizing agent tends to volatilize and tends to be difficult to handle. Moreover, when n exceeds 400, there exists a tendency for the compatibility of this organic vulcanizing agent and rubber to deteriorate.

  In the formula, m is preferably an integer of 2 to 5, more preferably an integer of 2 to 4, and still more preferably an integer of 2 to 3. If m is less than 2, the bending resistance tends to decrease. On the other hand, if m exceeds 5, the hardness of the rubber composition tends to be insufficient.

  The content of the organic vulcanizing agent is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, and still more preferably 2 parts by weight or more with respect to 100 parts by weight of the rubber component. When the content of the organic vulcanizing agent is less than 0.5 parts by weight, the wear resistance tends to deteriorate. Further, the content of the organic vulcanizing agent is preferably 30 parts by weight or less, and more preferably 25 parts by weight or less. When the content of the organic vulcanizing agent exceeds 30 parts by weight, the hardness increases excessively and the grip performance tends to deteriorate.

  In addition to the rubber component, silica (1) and (2), and organic vulcanizing agent, the rubber composition of the present invention is used in addition to silica such as carbon black and clay, which are generally used in the production of rubber compositions. Reinforcing fillers, anti-aging agents, softeners, zinc oxide, stearic acid, wax, vulcanizing agents other than organic vulcanizing agents, silane coupling agents, vulcanization accelerators, processing aids, etc., as necessary A commonly used amount can be included.

  The tire of the present invention is preferably made of the rubber composition, and particularly preferably has a tread using the rubber composition. The tread is formed by laminating a sheet of rubber composition into a predetermined shape, or by inserting the rubber composition into two or more extruders and forming two layers at the head outlet of the extruder. It can produce by the method to do.

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

Various chemicals used in Examples and Comparative Examples are described in detail below.
SBR: E15 manufactured by Asahi Kasei Corporation
Silica (1): Ultrasil 360 manufactured by Degussa (hydrous silica produced by a wet method, N ₂ SA: 50 m ² / g)
Silica (2): Rhodia Zeosyl 1205MP (hydrous silica produced by a wet method, N ₂ SA: 200 m ² / g)
Silica (3): Ultrasil VN3 manufactured by Degussa (hydrous silica produced by a wet method, N ₂ SA: 175 m ² / g)
Aromatic oil: Diana Process Oil AH-24 manufactured by Idemitsu Kosan Co., Ltd.
Zinc oxide: Zinc oxide stearic acid manufactured by Mitsui Mining & Smelting Co., Ltd.
Anti-aging agent: Antigen 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
Wax: Sunnock N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Sulfur: Powder sulfur organic vulcanizing agent manufactured by Karuizawa Sulfur Co., Ltd .: 2OS4 manufactured by Kawaguchi Chemical Industry Co., Ltd. (in the above general formula of organic vulcanizing agent, m = 2, x = 4, n = 200)
Vulcanization accelerator CZ: Noxeller CZ (N-cyclohexyl-2-benzothiazylsulfenamide) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Vulcanization accelerator DPG: Noxeller D (N, N′-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

Examples 1-7 and Comparative Examples 1-3
According to the formulation shown in Tables 1 and 2, SBR, silica (1) to (3), aromatic oil, zinc oxide, stearic acid, anti-aging agent and wax were kneaded for 3 minutes using a Banbury mixer, Furthermore, sulfur, an organic vulcanizing agent, and a vulcanization accelerator were kneaded with a roll as a vulcanizing agent to obtain each kneaded product. Each kneaded product is formed into a tread shape, bonded to another tire member, and vulcanized to produce test tires (tire size: 195 / 65R15) of Examples 1 to 7 and Comparative Examples 1 to 3. did.

(Rolling resistance performance)
Using a rolling resistance tester, the rolling resistance of the test tire was measured under the conditions of rim size (15 × 6JJ), tire internal pressure (230 kPa), load (3.43 kN), and speed (80 km / h). In Table 1, the rolling resistance value of Comparative Example 1 was set to 100, and the other values were displayed as indices. Moreover, in Table 2, the rolling resistance value of Example 5 was set to 100, and the other values were displayed as indices. The larger the index, the lower the rolling resistance and the better the rolling resistance performance.

(Wet skid performance)
The test tire was mounted on all the wheels of a vehicle (domestic FF2000cc), and the braking distance from the point where the brake was applied on the wet asphalt road surface at a speed of 100 km / h was determined. And each braking distance was applied to the following formula | equation, and each was represented by the index | exponent. The larger the index, the better the wet skid performance.
Wet skid performance index in Table 1 =
(Braking distance of comparative example 1) ÷ (braking distance of each example or each comparative example) × 100
Wet skid performance index in Table 2 =
(Brake distance of Example 5) ÷ (Brake distance of each Example) × 100

(Steering stability)
The test tires were mounted on all the wheels of a vehicle (domestic FF2000cc) and the vehicle was run on the test course, and the steering stability was evaluated by sensory evaluation of the driver. In Table 1, relative evaluation was performed with Comparative Example 1 as 6 points and Table 2 as Example 5 as 6 points. The larger the value, the better the steering stability and the better.

  Table 1 shows the test results of rolling resistance performance, wet skid performance, and steering stability in Examples 1-2 and Comparative Examples 1-3.

(Abrasion resistance)
Tires were mounted on all wheels of a vehicle (domestic FF2000cc), and after running 30000 km, the groove depth of the tread pattern was determined, and the reciprocal number thereof was calculated. And the reciprocal number of the depth of the groove | channel of Example 5 was set to 100, the other reciprocal number was shown with the index | index, and it was set as the abrasion-resistant index | exponent. The higher the index, the better the wear resistance.

  Table 2 shows test results of rolling resistance performance, wet skid performance, steering stability and wear resistance in Examples 3 to 7.

Claims (3)

For 100 parts by weight of rubber component,
(1) A rubber composition containing a total of 30 to 150 parts by weight of silica having a nitrogen adsorption specific surface area of 100 m ² / g or less and (2) a silica having a nitrogen adsorption specific surface area of 180 m ² / g or more,
A rubber composition in which the contents of silica (1) and (2) satisfy the following formula.
[Content of silica (1)] × 0.2 ≦ [Content of silica (2)]
≦ [Content of silica (1)] × 6.5 General formula − (R−S _x ) _n −
(Wherein, R is _{(CH 2 -CH 2 -O) m} -CH 2 -CH 2, x is an integer of 3 to 6, n represents an integer of 10 to 400, m is an integer of 2-5 .)
The rubber composition according to claim 1, which contains 0.5 to 30 parts by weight of an organic vulcanizing agent satisfying the above. A tire having a tread using the rubber composition according to claim 1.