JP2008201827A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire suppressing a bloomed material inhibiting the mutual adhesion of unvulcanized rubbers, enhancing adhesiveness after vulcanization and achieving high durability. <P>SOLUTION: The pneumatic tire is obtained by using a rubber composition prepared by compounding a vulcanizable rubber component with a polymer fatty acid zinc salt. In the pneumatic tire, the amount of the compounded polymer fatty acid zinc salt is 0.1-10 pts.mass based on 100 pts.mass of the vulcanizable rubber component. Furthermore, the amount of the compounded polymer fatty acid zinc salt is 0.5-10 pts.mass based on 100 pts.mass of the vulcanizable rubber component in the pneumatic tire. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to an aircraft pneumatic tire used at a high internal pressure and at a high speed and a high load.

  Modern tire rubber compositions, not limited to pneumatic tires for aircraft, have made processing of unvulcanized rubber extremely difficult as a compensation to satisfy a wide range of desirable performance. Therefore, conventionally, there are rubber compositions to which fatty acids and various metal salts of fatty acids are added as processing aids, and various esters such as pentaerythritol tetrastearate (Patent Document 1), monoglyceride, rice bran wax and the like as processing aids. And paraffin wax are used.

It is also known that cement rubber is used at the interface for the purpose of bonding between unvulcanized rubber members, thereby improving the workability of the unvulcanized rubber.
Japanese Patent Laid-Open No. 1-115943

  However, although the process using various esters as a processing aid can be expected to improve processability, there is a problem of poor rubber-rubber adhesion resulting from bloom / bleed of unvulcanized rubber.

  In addition, the use of cement rubber is not so preferable in recent years due to the environmental impact caused by the discharge of organic solvents blended in cement rubber.

  By the way, in large tires such as aircraft tires, there is a period in which unvulcanized rubber is allowed to stand for 6 hours to 3 days or more in some cases in the production process, during which the vulcanized system is applied to the surface of the unvulcanized rubber. There was a problem that chemicals, antioxidants, waxes, fatty acids, and various metal salts of fatty acids bleed out and hinder the processability of unvulcanized adhesives and the like.

  In addition, since large tires such as aircraft tires are vulcanized at a relatively low temperature in the vulcanization process, vulcanization proceeds below the melting point of various blooms, and between rubber and rubber due to blooms. There was also a problem that interface peeling or peel-off due to poor adhesion occurred and the durability of the tire was lowered.

  In particular, zinc stearate as a bloom in unvulcanized rubber has a high melting point, and large tires that are vulcanized at low temperatures have a problem in terms of rubber-rubber adhesion durability.

  Accordingly, an object of the present invention is to provide a pneumatic tire that suppresses blooms that inhibit adhesion between unvulcanized rubbers, enhances adhesion after vulcanization, and achieves high durability.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the object can be achieved by blending a polymer fatty acid zinc salt with a rubber composition, and the present invention has been completed. .

  That is, the pneumatic tire of the present invention is characterized by using a rubber composition in which a polymer fatty acid zinc salt is blended with a vulcanizable rubber component.

  In the pneumatic tire of the present invention, the amount of the high-molecular fatty acid zinc salt is preferably 0.1 to 10 parts by mass, more preferably 0.8 to 100 parts by mass of the vulcanizable rubber component. 5 to 10 parts by mass. Moreover, it is preferable that natural rubber and / or synthetic isoprene rubber 40-100 mass parts and butadiene rubber 0-60 mass parts are contained in 100 mass parts of said vulcanizable rubber components. Furthermore, the rubber composition is preferably used as a tread member, and is preferably an aircraft tire.

  According to the present invention, it is possible to provide a pneumatic tire that suppresses blooms that inhibit the adhesion between unvulcanized rubbers, enhances adhesion after vulcanization, and realizes high durability. Therefore, even in the case of aircraft tires that have been left in the state of unvulcanized rubber in the production process for 6 hours to 3 days, depending on the case, it is excellent in peeling resistance and between tire members such as peel-off due to cuts, etc. It is possible to significantly improve the rubber-rubber adhesion durability, which is a problem of (1).

Embodiments of the present invention will be specifically described below.
The vulcanizable rubber component used in the present invention is not particularly limited. For example, natural rubber or synthetic rubber such as styrene-butadiene copolymer rubber, butadiene rubber, or isoprene rubber may be used alone or in combination. Can do. Among these, in order to obtain the desired effect of the present invention, as a vulcanizable rubber component, 100 to 100 parts by mass of the rubber component, 40 to 100 parts by mass of natural rubber and / or synthetic isoprene rubber, and 0 to 60 of butadiene rubber. What contains a mass part can be used suitably.

  As the polymer fatty acid zinc salt used in the present invention, for example, those sold as peptizers such as trade names Aktiplast (Rhein Chemie), ULTRAFLOW (Performance Additives) and the like are suitable.

  The blending amount of the high-molecular-weight fatty acid zinc salt only needs to exert an inhibitory action on the generation of blooms, in particular, zinc stearate blooms that inhibit the adhesion between unvulcanized rubber components, and is preferably vulcanizable. It is 0.1 to 10 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component. If the amount of the polymeric fatty acid zinc salt used in the present invention is less than 0.1 parts by mass, it is difficult to sufficiently exert the bloom inhibitory effect. On the other hand, if it exceeds 10 parts by mass, an increase in the bloom inhibitory effect cannot be expected. It becomes too soft and causes a decrease in rubber properties.

  Here, in this invention, a bloom thing is a substance which bleeds out on the rubber surface and inhibits processability, such as unvulcanized adhesion. Specifically, vulcanized chemicals on the surface of unvulcanized rubber (sulfur, zinc white, vulcanization accelerators (thiazoles, sulfenamides, dithioates)), antioxidants, waxes, fatty acids, Various metal salts of fatty acids, particularly zinc stearate.

  Since the rubber composition according to the present invention is used for pneumatic tires, there is a rubber-rubber interface between all rubber members in the molding process, and there is no limitation as a member. As a problem, it is preferably used for a tread member that is susceptible to bloom.

  The pneumatic tire of the present invention is preferably an aircraft pneumatic tire. By making it a pneumatic tire for aircraft, the generation of blooms is suppressed even when left in the state of unvulcanized rubber for a long time. As a result, it has excellent peeling resistance between rubber interfaces, resulting in cuts, etc. The rubber-rubber adhesion durability, which is a problem between tire members such as peel-off, can be significantly improved.

  Other compounding agents that can be used in the rubber composition used in the present invention include carbon black, vulcanizing agent, vulcanization accelerator, anti-aging agent, anti-scorching agent, softening agent, zinc oxide, stearic acid, and silane. The compounding agents normally used in the rubber industry such as a coupling agent can be mentioned. As these compounding agents, commercially available products can be suitably used.

  In addition, the rubber composition used for this invention can be manufactured by knead | mixing a rubber component and the various compounding agents selected suitably as needed, heat-inserting, extrusion, etc.

  EXAMPLES Next, although an Example demonstrates this invention in more detail, this invention is not limited by this example.

Examples 1 and 2 and Comparative Examples 1 and 2
According to the formulation shown in Table 1 below, rubber compositions of each example and comparative example were prepared. About the obtained rubber composition, bloom property, adhesiveness, and peel-off resistance were evaluated by the following methods.

(Blooming)
A sheet having a length of 100 mm, a width of 20 mm, and a thickness of 5 mm was produced from the test rubber composition. Subsequently, after leaving the obtained sheet | seat at room temperature for 3 days, the surface state was observed and the presence or absence of the bloom thing was investigated visually.
Bloom evaluation ○: None △: Some

(Adhesiveness: unvulcanized peeling test)
Two sheets each having a length of 100 mm, a width of 20 mm, and a thickness of 5 mm were produced from the test rubber composition. Next, the obtained sheet was allowed to stand at room temperature for 3 days and then bonded to prepare an unvulcanized sample. The unvulcanized sample was evaluated by a peeling test using a strograph. The test apparatus used was a Toyo Seiki Co., Ltd. Strograph AR-1, and the test conditions were compliant with JIS-K-6256. The peel strength result of Example 1 was shown as an index, which was taken as 100. In this case, it shows that it is excellent in unvulcanized rubber adhesiveness, so that a numerical value is large.

(Peel-off resistance)
First, a pneumatic radial tire for an aircraft having a tire size: 1270 × 445R22 32PR was produced using the test rubber composition as a rubber composition for a tread. These tires all have the same tire structure.

  Next, the peel-off resistance of the prototyped pneumatic radial tire for aircraft was evaluated as follows. That is, after forming a cut scar having a width of 400 mm in the tire width direction and a depth of 15 mm in the tread center portion of the test tire under an internal pressure of 1620 kPa, the tread is peeled off under a specified load (24860 kg) on the drum tester. The vehicle was run until (peel off) occurred, and the drum speed at the time when peel off occurred in Example 1 was indicated as an index. In this case, it shows that it is excellent in peel-off resistance, so that a numerical value is large.

＊１ ＢＲ０１（ＪＳＲ製、ブタジエンゴム）
＊２ Ｎ３３０（カーボンブラック）
＊３ ノクセラーＮＳ（大内新興化学工業株式会社製）
＊４ 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
＊５ Ａｋｔｉｐｌａｓｔ ＰＰ（ラインケミー社製）

* 1 BR01 (JSR, butadiene rubber)
* 2 N330 (carbon black)
* 3 Noxeller NS (Ouchi Shinsei Chemical Co., Ltd.)
* 4 N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine * 5 Aktiplast PP (Rhein Chemie)

Claims (6)

  A pneumatic tire comprising a rubber composition in which a polymer fatty acid zinc salt is blended with a vulcanizable rubber component.   2. The pneumatic tire according to claim 1, wherein a blending amount of the polymer fatty acid zinc salt is 0.1 to 10 parts by mass with respect to 100 parts by mass of the vulcanizable rubber component.   The pneumatic tire according to claim 2, wherein the amount of the high-molecular-weight fatty acid zinc salt is 0.5 to 10 parts by mass with respect to 100 parts by mass of the vulcanizable rubber component.   The natural rubber and / or synthetic isoprene rubber 40-100 mass parts and the butadiene rubber 0-60 mass parts are contained in 100 mass parts of the vulcanizable rubber components, respectively. Pneumatic tire.   The pneumatic tire according to any one of claims 1 to 5, wherein the rubber composition is used as a tread member.   The pneumatic tire according to any one of claims 1 to 5, which is an aircraft tire.