JP5228365B2 - Rubber composition for tire - Google Patents

Description

  The present invention relates to a rubber composition for tires, and more particularly to a rubber composition suitable for use in a tread of a studless tire having particularly improved frictional force on ice.

  As a technique for increasing the frictional force between rubber and ice required for studless tires, a technique for blending thermally expandable microcapsules or expanded graphite with diene rubber has been known (see, for example, Patent Documents 1 and 2). ), Further improvement of the frictional force between rubber and ice is demanded.

JP 2001-279020 A JP 2002-356484 A

  Accordingly, an object of the present invention is to develop a technique for further increasing the frictional force between rubber and ice required for a studless tire.

  According to the present invention, there is provided a tire rubber composition comprising 100 parts by weight of a diene rubber and 1 to 15 parts by weight of water-retaining plant seeds.

  According to the present invention, as a technique for increasing the frictional force between rubber and ice required for studless tires, the frictional force on ice was successfully improved by blending water-retaining plant seeds with diene rubber.

  As a result of the development aimed at improving the frictional force between rubber and ice in order to solve the above problems, the present inventor succeeded in improving the frictional force on ice by blending water-retaining plant seeds.

  According to the present invention, 1 to 15 parts by weight, preferably 1.5 to 5 parts by weight of water-retaining plant seeds are blended with 100 parts by weight of diene rubber. If the blending amount is small, the desired effect cannot be obtained, which is not preferable. On the other hand, if the blending amount is large, the frictional force on ice increases, but the wear resistance decreases, which is not preferable. Examples of water-retaining plant seeds used in the present invention include the following.

Basil seed (country of origin: Thailand)
Basilico is also known by the English name Basil. Indica is an annual plant of the genus Lamiaceae native to tropical Asia. Basilico seeds are covered with jelly-like substances when they contain water, and because they are rich in glucomannan, they expand about 30 times the dry state. Has nature.

Chia seed (country of origin: Mexico)
Chia seeds are traditionally consumed in Mexico, the southwestern United States and South America, and not widely known in Europe or Asia. Chia (chia is a kind of mint genus Salvia) is a seed with a small oval shape of about 1 mm, usually brown, gray, black and white mottled color, which is also basil Water-retaining seeds such as seeds.

  By blending the water-retaining seeds with the rubber composition, the water stored by the water absorption of the seeds is frozen by contact with the road surface, and is integrated with the road surface. is there. Even if these water-retaining plant seeds are pulverized to an average particle size of 50 to 500 μm using, for example, a freeze pulverizer manufactured by Sampleratec, the frictional force on ice is improved and the wear resistance is also improved.

  In another embodiment of the present invention, the rubber composition is further mixed with 1 to 15 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of the diene rubber, on the ice. The frictional force can be further increased. If the blending amount is small, the desired water absorption effect cannot be obtained, which is not preferable. On the other hand, if the blending amount is large, the wear resistance is decreased. The thermally expandable microcapsule that can be used in the present invention is a thermally expandable thermoplastic resin particle in which a liquid or solid that generates a gas by vaporization, decomposition, or chemical reaction by heat is encapsulated in a thermoplastic resin. When the particles are heated and expanded at a temperature equal to or higher than the expansion start temperature, usually 140 to 190 ° C., a product in which a gas is contained in the outer shell made of the thermoplastic resin is generated. The particle size of the thermally expandable thermoplastic resin particles is preferably 5 to 300 μm, more preferably 10 to 200 μm. Examples of such thermally expandable thermoplastic resin particles are available from Matsumoto Yushi Seiyaku Co., Ltd. under the trade name “Matsumoto Microsphere F-85” or “Matsumoto Microsphere F-100”. It is also available as EXPANCEL 091DU-80 or EXPANSEL 092DU-120 from EXPANCEL, Sweden.

  The diene rubber blended as a main component in the vulcanizable rubber composition according to the present invention is any diene rubber conventionally blended in various rubber compositions, such as natural rubber (NR), polyisoprene. Examples thereof include rubber (IR), various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), acrylonitrile-butadiene copolymer rubber (NBR), and butyl rubber (IIR). These diene rubbers can be used alone or as any blend. These diene rubbers can also be used by blending with a relatively small amount of ethylene-propylene copolymer rubber (EPR, EPDM) or the like.

  In addition to the components described above, the rubber composition according to the present invention includes other reinforcing agents (fillers) such as carbon black and silica, vulcanization or crosslinking agents, vulcanization or crosslinking accelerators, various oils, and anti-aging agents. Various additives generally blended for tires such as plasticizers and other rubber compositions can be blended, and these additives are kneaded by a general method to obtain a composition and vulcanized. Or it can be used to crosslink. As long as the amount of these additives is not contrary to the object of the present invention, a conventional general amount can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, it cannot be overemphasized that the scope of the present invention is not limited to these Examples.

Examples 1-7 and Comparative Examples 1-3
Sample preparation In the formulation shown in Table I, ingredients other than the vulcanization accelerator, sulfur and thermally expandable microcapsules were kneaded for 5 minutes with a 1.7 liter closed Banbury mixer, and the rubber was discharged out of the mixer. The master batch was obtained by cooling at room temperature. A rubber composition was obtained by blending and mixing the vulcanization accelerator, sulfur and thermally expandable microcapsules with this master batch using the same Banbury mixer.

  Next, the resulting rubber composition was vulcanized in a 15 × 15 × 0.2 cm mold at 170 ° C. for 15 minutes to prepare a vulcanized rubber sheet. The physical properties of the vulcanized rubber were measured by the following test methods. It was measured. The results are shown in Table I.

Rubber physical property evaluation test method Frictional force on ice: A sheet-like rubber piece obtained by vulcanizing each compound was attached to a flat cylindrical base rubber, and a friction coefficient on ice was measured with an inside drum type on-ice friction tester (measurement temperature: -1 0.5 ° C., load: 0.54 MPa, drum rotation speed: 25 km / h). The results are shown as an index with Comparative Example 1 as 100. Larger numbers indicate better friction between rubber and ice.

  Abrasion resistance: Measured using a Lambourn abrasion tester in accordance with JIS K6264 under conditions of a load of 39 N and a slip ratio of 30%. The results are shown as an index with Comparative Example 1 as 100. Larger numbers indicate better wear resistance.

Table I Footnote NR: Natural rubber RSS # 3
BR: Nipol BR1220 manufactured by Nippon Zeon Co., Ltd.
CB: Tokai Carbon Co., Ltd. Seast 6
Silica: Nippon Sil AQ manufactured by Nippon Silica Industry Co., Ltd.
Si69: Dexa SI69
Zinc oxide: Zinc oxide 3 types, manufactured by Shodo Chemical Industry Co., Ltd. Stearic acid: Beads stearic acid, manufactured by NOF Corporation Anti-aging agent: SANTOFLEX 6PPD manufactured by Flexis
Aroma oil: Aroma oil manufactured by Fuji Kosan Co., Ltd. Sulfur: Fine powder sulfur containing Kinka Ink Oil, manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator: Noxeller CZ-G manufactured by Ouchi Shinsei Chemical Co., Ltd.
Water retention seed A: Chia seed (seller: in the Beauty Takao Kume) (average particle size: about 1 mm)
Water retention seed B: Basil seed (seller: Shiba Trading) (average particle size: about 1 mm)
Thermally expandable microcapsule: Microsphere F100D manufactured by Matsumoto Yushi Seiyaku Co., Ltd.

  According to the present invention, as a technique for increasing the frictional force between rubber and ice required for studless tires, by adding water-retaining plant seeds to diene rubber, further optionally adding thermally expandable microcapsules. Thus, the frictional force on ice can be further improved.

Claims (3)

A rubber composition for tires comprising 100 parts by weight of a diene rubber and 1 to 15 parts by weight of water-retaining plant seeds selected from basil seeds and / or chia seeds. The tire rubber composition according to claim 1 , further comprising 1 to 15 parts by weight of thermally expandable microcapsules with respect to 100 parts by weight of the diene rubber. The tire rubber composition according to claim 1 or 2 , wherein the water-retaining plant seed has an average particle size of 50 to 500 µm.