JP2008208265A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition giving a high grip performance without reducing operation performances and wear resistance in low temperatures and provide a tire using it as a tread member. <P>SOLUTION: The rubber composition incorporates one or more kinds of resins (A) selected from alkylphenol resins and one or more kinds of resins (B) selected from terpenes and terpene-phenol resins in the rubber component that contains 40 pts.mass or more of a styrene-butadiene copolymer rubber. The tire using it is also provided. It is preferable that the resin (A) and the resin (B) are formulated in a mass ratio of 10:1-1:10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber composition and a pneumatic tire using the same, and more particularly to a rubber composition for a tire tread that exhibits excellent grip performance and a pneumatic tire using the same.

  In recent years, with the improvement of automobile performance, road paving and the development of highway networks, there is an increasing demand for pneumatic tires with high movement performance. The higher this characteristic, the faster and more accurately and safely it is possible to travel. In particular, grip performance represented by acceleration performance and brake performance is an important required characteristic.

  Conventionally, in order to obtain high grip performance, there has been a method of using a styrene-butadiene copolymer rubber having a high styrene content, which is a rubber having a high glass transition temperature, in a tire tread rubber composition. However, this method has a disadvantage that the tan δ value decreases as the rubber temperature increases due to running, so that the grip performance decreases as the tire temperature increases.

Therefore, in order to eliminate this inconvenience, a monomer such as 1,3-butadiene, styrene or isoprene and a diphenyl phosphate group such as diphenyl-2-methacryloyloxyethyl phosphate or diphenyl-2-acryloyloxyethyl phosphate are included. A technique (Patent Document 1) using a copolymer rubber obtained by copolymerizing a methacrylate compound or an acrylate compound has been proposed.
JP 59-187011 A

  However, this method is not only applicable to natural rubber, but also has the disadvantage of impairing the inherent properties of polymers such as styrene / butadiene copolymer rubber and polybutadiene rubber depending on the production conditions.

  On the other hand, there is also a method to increase the tan δ value of the rubber composition by using a compound system that is highly filled with process oil and carbon black, but this method improves the grip performance, but it also has fracture characteristics and wear resistance. Therefore, there is a limit to high filling, and it is difficult to obtain a required level of high grip performance.

  Furthermore, there is a method for improving the grip performance by adding a certain kind of resin to improve adhesion between the rubber and the road surface. Generally, a resin having a higher grip performance has a metal mixer existing in the manufacturing process and Adhesiveness with a metal roll becomes high and tends to inhibit factory workability. Therefore, it is actually difficult to improve the grip performance by improving the resin. In addition, the terpene phenol resin alone has a disadvantage that the operability at low temperatures is improved but the grip performance is not improved.

  Accordingly, an object of the present invention is to provide a rubber composition capable of obtaining high grip performance without deteriorating operability and wear resistance at low temperatures, and a pneumatic tire using the rubber composition.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by combining an alkylphenol resin and a terpene and / or a terpene phenol resin in a rubber composition. The present invention has been completed.

  That is, the rubber composition of the present invention comprises at least one resin (A) selected from alkylphenol resins, a terpene resin and a terpene phenol resin with respect to a rubber component containing 40 parts by mass or more of styrene / butadiene copolymer rubber. One or more resins (B) selected from the above are blended.

  In the rubber composition of this invention, it is preferable that the said resin (A) and the said resin (B) are mix | blended by the mass ratio of 10: 1 to 1:10, and it is 100 mass parts of said rubber components. On the other hand, it is preferable that the total mass part of the said resin (A) and the said resin (B) is 3-100 mass parts. The styrene / butadiene copolymer rubber preferably contains 20 to 70% by mass of styrene, and the main structure of the phenol moiety of the alkylphenol resin is preferably a p-tert-butylphenol structure. Furthermore, the resin (B) contains at least the terpene phenol resin, and the OH value of the terpene phenol resin is preferably 170 or less, and the softening point of the alkylphenol resin is preferably 120 ° C. or more.

  The pneumatic tire of the present invention is characterized by using the rubber composition as a tread member.

  According to the present invention, it is possible to provide a rubber composition and a pneumatic tire using the rubber composition capable of significantly improving high grip performance without deteriorating operability and wear resistance at low temperatures. .

Embodiments of the present invention will be specifically described below.
The rubber composition of the present invention contains 40 parts by mass or more of styrene / butadiene copolymer rubber as a rubber component, and other rubber components may be used alone or in combination with natural rubber and synthetic rubber. Synthetic polyisoprene rubber, polybutadiene rubber, styrene / butadiene copolymer rubber, halogenated butyl rubber, EPDM rubber and the like. If the rubber composition contains less than 40 parts by mass of styrene / butadiene copolymer rubber, which is a rubber component, the desired effects of the present invention cannot be obtained, which is not preferable. The styrene / butadiene copolymer rubber preferably contains 20 to 70% by mass of styrene in order to obtain a desired effect.

  In the rubber composition of this invention, it is necessary to mix | blend 1 or more types of resin (A) chosen from alkylphenol resin, and 1 or more types of resin (B) chosen from terpene resin and terpene phenol resin. . It is essential to mix the resin (A) and the resin (B), and in either case, the desired effect of the present invention cannot be obtained.

  In the rubber composition of the present invention, the mass ratio of the resin (A) to the resin (B) is preferably 10: 1 to 1:10. If this mixing ratio is out of 10: 1 to 1:10, the desired effect of the present invention cannot be sufficiently obtained.

  Furthermore, in the rubber composition of the present invention, the total amount of the resin (A) and the resin (B) is preferably 3 to 100 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is 3-90 mass parts, More preferably, it is 3-80 mass parts. If the total amount is less than 3 parts by mass, the desired effect of the present invention cannot be sufficiently obtained. On the other hand, if it exceeds 100 parts by mass, the desired performance cannot be obtained sufficiently and at the same time after vulcanization. This is not preferable because it may adversely affect various physical properties.

  The one or more resins (A) selected from the alkylphenol resins used in the present invention preferably have a raw material monomer of tert-butylphenol or tert-octylphenol, and include p-tert-butylphenol-formaldehyde resin and p-tert-butylphenol. -Acetaldehyde resin is more preferable. Furthermore, in order to obtain the desired effect of the present invention, the softening point of the alkylphenol resin is preferably 120 ° C. or higher, more preferably 120 to 160 ° C. An alkylphenol resin may be used individually by 1 type, or may use 2 or more types together.

  One or more resins (B) selected from terpene resins and terpene phenol resins used in the present invention may be any as long as the starting terpene is α-pinene, β-pinene, dipentene, or limonene. The OH value of the terpene phenol resin is preferably 170 or less in order to obtain the desired effect of the present invention. A terpene resin or terpene phenol resin may be used individually by 1 type, or may use 2 or more types together.

  In the rubber composition of the present invention, carbon black, silica, alumina, aluminum hydroxide, calcium carbonate, titanium oxide and the like can be used alone or in combination of two or more as a replenishing filler. Preferably carbon black is used.

  In the present invention, in addition to the above-mentioned raw rubber, refillable filler, and resin, compounding agents that are usually used in the rubber industry, such as softeners, anti-aging agents, coupling agents, and vulcanization accelerator An agent, a vulcanization accelerating aid, a vulcanizing agent, and the like can be blended within the range of ordinary blending amounts as necessary.

  Moreover, the rubber composition of this invention can be used as a tread member for a pneumatic tire. Thereby, high grip performance can be obtained without deteriorating operability and wear resistance at low temperatures.

EXAMPLES Next, although an Example demonstrates this invention in more detail, this invention is not limited by this example.
A rubber composition for a tire tread was prepared by kneading using a Banbury mixer according to the formulation (parts by mass) shown in Tables 1 to 3 below. The obtained rubber composition was vulcanized at 160 ° C. for 15 minutes, and the grip performance was evaluated. The tire grip performance was evaluated by the following method. The obtained evaluation results are shown in Tables 1 to 3 below.

(Hysteresis characteristics)
For vulcanized rubber obtained by vulcanizing each rubber composition, tan δ at 50 ° C. was measured under a dynamic strain of 1% using a rheometrics viscoelasticity measuring tester, and compared. The rubber composition of Example 1 was expressed as an index with tan δ of 100. The larger the index value, the larger the tan δ, indicating that the grip performance is excellent.

(Dry skid property)
The evaluation was made on a dry road surface by a skid tester (manufactured by Stanley London Co.), and a numerical value with Comparative Example 1 as 100 was shown. The larger this value, the better.

(Grip property)
The grip properties of the rubber composition were evaluated by reproducing a dry road surface using a dry skid tester. In addition, the grip performance of the tire was evaluated by producing a tire having a tire size of 225 / 40R18 using the rubber composition as a tread. Four tires described above were mounted on a passenger car and run on a dry asphalt road test course for evaluation. The grip performance was evaluated by a test driver in seven stages.
7 stages 7: Very good, 6: Good, 5: Somewhat good, 4: Normal, 3: Somewhat bad, 2: Bad, 1: Very bad,-: Not rated

＊１ 旭化成製タフデン４３５０（結合スチレン含有率３９％、ビニル結合量３８％、ゴム成分１００質量部に対し５０質量部のアロマチックオイルで油展）
＊２ カーボンブラック（ＣＴＡＢ吸着法による外部表面積１４８ｍ^２／ｇ、２４Ｍ４ＤＢＰ吸油量１０２ｍＬ／１００ｇ）
＊３ コレシン（ＢＡＳＦ社製）
＊４ Ｄｕｒｅｚ３２３３３（Ｄｕｒｅｚ社製、ｐ−ｔｅｒｔブチルフェノール・ホルムアルデヒド樹脂、軟化点１３０℃）
＊５ テルペンフェノール樹脂ＹＳポリスターＳ１４５（ヤスハラケミカル株式会社製、軟化点１４５℃、ＯＨ価１２０）
＊６ テルペンフェノール樹脂ＹＳポリスターＴ１４５（ヤスハラケミカル株式会社製、軟化点１４５℃、ＯＨ価７０）
＊７ テルペンフェノール樹脂ＹＳポリスターＴ１６０（ヤスハラケミカル株式会社製、軟化点１６０℃、ＯＨ価７０）
＊８ テルペンフェノール樹脂ＹＳポリスターＴ１００（ヤスハラケミカル株式会社製、軟化点１００℃、ＯＨ価７０）
＊９ テルペンフェノール樹脂マイティエースＫ１２５（ヤスハラケミカル株式会社製、軟化点１２５℃、ＯＨ価２１０）
＊１０ テルペン樹脂クリアロンＰ１５０（ヤスハラケミカル株式会社製、軟化点１５０℃、ＯＨ価０）
＊１１ Ｎ−１，３−ジメチル−ブチル−Ｎ’−フェニル−ｐ−フェニレンジアミン
＊１２ Ｎ−ｔ−ブチル−２−ベンゾチアジル−スルフェンアミド
＊１３ テトラキス−２−エチルヘキシルチウラムジスルフィド

* 1 Toughden 4350 manufactured by Asahi Kasei Co., Ltd. (bonded styrene content 39%, vinyl bond amount 38%, 50 parts by weight of aromatic oil for 100 parts by weight of rubber component)
* 2 Carbon black (external surface area by CTAB adsorption method: 148m ² / g, 24M4DBP oil absorption: 102mL / 100g)
* 3 Colesin (BASF)
* 4 Durez32333 (Durez, p-tertbutylphenol / formaldehyde resin, softening point 130 ° C.)
* 5 Terpene phenol resin YS Polyster S145 (manufactured by Yashara Chemical Co., Ltd., softening point 145 ° C., OH value 120)
* 6 Terpene phenol resin YS Polystar T145 (manufactured by Yashara Chemical Co., Ltd., softening point 145 ° C., OH value 70)
* 7 Terpene phenol resin YS Polystar T160 (Yasuhara Chemical Co., Ltd., softening point 160 ° C., OH value 70)
* 8 Terpene phenol resin YS Polystar T100 (Yasuhara Chemical Co., Ltd., softening point 100 ° C., OH value 70)
* 9 Terpene phenol resin Mighty Ace K125 (Yasuhara Chemical Co., Ltd., softening point 125 ° C, OH value 210)
* 10 Terpene resin Clearon P150 (Yasuhara Chemical Co., Ltd., softening point 150 ° C, OH value 0)
* 11 N-1,3-dimethyl-butyl-N'-phenyl-p-phenylenediamine * 12 Nt-butyl-2-benzothiazyl-sulfenamide * 13 tetrakis-2-ethylhexylthiuram disulfide

  Comparative Examples 1-8 show the result of blending each of a phenol resin, a terpene resin or a terpene phenol resin alone, and Examples 1-14 are a mixture of a phenol resin and a terpene resin or a terpene phenol resin. The result of blending is shown. As is clear from Tables 1 to 3, Examples 1 to 14 all had high tan δ at 50 ° C. and good dry skid properties. In addition, Examples 1 to 14 have good vehicle evaluation results, and in Examples 4, 5 and 9 to 11, good results were obtained.

Claims (8)

  One or more resins selected from alkylphenol resins (A) and one or more resins selected from terpene resins and terpene phenol resins (B) with respect to a rubber component containing 40 parts by mass or more of styrene / butadiene copolymer rubber And a rubber composition comprising:   The rubber composition according to claim 1, wherein the resin (A) and the resin (B) are blended in a mass ratio of 10: 1 to 1:10.   The rubber composition according to claim 1 or 2, wherein a total mass part of the resin (A) and the resin (B) is 3 to 100 parts by mass with respect to 100 parts by mass of the rubber component.   The rubber composition according to any one of claims 1 to 3, wherein the styrene-butadiene copolymer rubber contains 20 to 70% by mass of styrene.   The rubber composition according to any one of claims 1 to 4, wherein a main structure of a phenol moiety of the alkylphenol resin is a p-tert-butylphenol structure.   The rubber composition according to claim 1, wherein the resin (B) includes at least the terpene phenol resin, and the terpene phenol resin has an OH value of 170 or less.   The rubber composition according to any one of claims 1 to 6, wherein a softening point of the alkylphenol resin is 120 ° C or higher.   A pneumatic tire using the rubber composition according to any one of claims 1 to 7 as a tread member.