Bando Chemical Industries, Inc.

Hisashi Matsuda

Shinji Takahashi

Hideaki Kawahara

Takayuki Okubo

Yuji Sekiguchi

A rubber composition contains a rubber component, polyparaphenylene terephthalamide short fibers, silica, and carbon black. The content of the silica is larger than the content of the carbon black.

Rubber composition and transmission belt using same

A friction transmission belt has a rubber layer forming a pulley contacting portion. The rubber layer is made of a rubber composition containing a crosslinked rubber component and crosslinked polyolefin particles. Examples of the crosslinked polyolefin particles can contain ultrahigh molecular weight polyolefin particles having an average molecular weight of 500,000 or more.

Friction transmission belt and manufacturing method therefor

At least part of a belt body of a transmission belt contacting a cord is made of a rubber composition containing ethylene-&#x3b1;-olefin elastomer as a rubber component and formed in such a manner that the rubber component is mixed with &#x3b1;,&#x3b2;-unsaturated fatty acid metallic salt and then is crosslinked using sulfur.

Transmission belt

A power transmission belt is used by being wound around a flat pulley so that an outer peripheral surface thereof contacts with the flat pulley. A portion forming the outer peripheral surface is made of a rubber composition including an ethylene-&#x3b1;-olefin elastomer as a rubber component thereof. The dynamic viscoelasticity properties of the rubber composition in a belt length direction satisfy ((a loss tangent tan &#x3b4; at a temperature of 25&#xb0; C. and a dynamic strain of 3.0%)/(a storage elastic modulus E' at a temperature of 25&#xb0; C. and a dynamic strain 3.0%))&#xd7;1000&#x2266;3.0 MPa, and (a storage elastic modulus E&#x2032; at a temperature of 25&#xb0; C. and a dynamic strain of 1.0%)/(a storage elastic modulus E&#x2032; at a temperature of 25&#xb0; C. and a dynamic strain of 3.0%)&#x2266;1.30.

Drive belt

A belt body () of a friction transmission belt (B) includes a pulley contacting portion () made of a rubber composition. The rubber composition forming the pulley contacting portion () includes an ethylene-&#x3b1;-olefin elastomer as a rubber component, and in the rubber composition, 10-50 parts by mass of calcium carbonate relative to 100 parts by mass of the rubber component, and carbon black whose DBP oil absorption amount measured according to the method A specified in Japanese Industrial Standards (JIS) K 6217-4 is 300 cm/100 g or more are mixed.

Friction transmission belt

A flat belt (B) includes a cord retaining layer () in which a cord () extending in a belt length direction and arranged helically at a certain pitch in a belt width direction is embedded, and an inner rubber layer () provided on a belt inner side of the cord retaining layer () and serving as a pulley contracting portion. The cord retaining layer () is made of a rubber composition containing short fibers () which are mixed in a rubber component in an amount of 1 to 20 parts by mass relative to 100 parts by mass of the rubber component, and are dispersed to be oriented in the belt width direction. The inner rubber layer () is made of a rubber composition not containing short fibers ().

Flat belt

A friction drive belt (B) includes a pulley contacting portion () which is made of a rubber composition of an ethylene-&#x3b1;-olefin elastomer as raw rubber in which carbon black having an iodine adsorption number of 40 mg/g or lower, and 3-10 parts by mass of short aramid fiber () relative to 100 parts by mass of the raw rubber are blended.

Friction drive belt and belt transmission system using the same

A drive belt includes an endless belt body made of an ethylene-&#x3b1;-olefin elastomer composition and a cord embedded in the belt body to form a spiral at a specified pitch in a widthwise direction of the belt. The drive belt has a bending stiffness not larger than 0.064 N&#xb7;cmper a belt width of 4.8 mm and the belt body has a Wallace rubber hardness not smaller than 60&#xb0;.

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Kobe, Japan

Hisashi Matsuda