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--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 at a temperature of 25 C. and a dynamic strain of 3.0%)/(a storage elastic modulus E at a temperature of 25 C. and a dynamic strain 3.0%))10003.0 MPa.sup.1, and (a storage elastic modulus E at a temperature of 25 C. and a dynamic strain of 1.0%)/(a storage elastic modulus E at a temperature of 25 C. and a dynamic strain of 3.0%)1.30.

A power transmission belt having a base made of polyurethane and a textile overlay includes a first coating of a first thermoplastic material on the surface of the textile overlay. The first coating forms an impregnation, which has a melting temperature from 80 C. to approximately 145 C., penetrates at least partially into the textile. A second thermoplastic material on the first coating has a higher melting point. The first and second coatings can be applied successively to the textile overlay before casting of the polyurethane or can be overlaid as individual films or as a multi-layer film, and they may be applied to the textile overlay by heat and pressure. The coating acts to reduce abrasion and prevents the through passage of the belt polyurethane.

A power transmission belt having a base made of polyurethane and a textile overlay includes a first coating of a first thermoplastic material on the surface of the textile overlay. The first coating forms an impregnation, which has a melting temperature from 80 C. to approximately 145 C., penetrates at least partially into the textile. A second thermoplastic material on the first coating has a higher melting point. The first and second coatings can be applied successively to the textile overlay before casting of the polyurethane or can be overlaid as individual films or as a multi-layer film, and they may be applied to the textile overlay by heat and pressure. The coating acts to reduce abrasion and prevents the through passage of the belt polyurethane.

An endless flat belt includes an inner rubber layer 1, a cord core 11 buried in the inner rubber layer 1 and spirally wound at a predetermined pitch in a width direction of the belt, and a reinforcement fabric 2 stuck to the inner rubber layer 1. The cord core comprises polyamide fiber. Opposite ends of the reinforcement fabric 2 are connected with each other into an endless form by adhesion or sewing. A surface rubber layer 3 is stuck to a surface of the reinforcement fabric 2 which is opposite a surface thereof stuck to the inner rubber layer 1.

A friction transmission belt includes a belt body looped over a pulley, and transmitting power. The belt body includes a rubber composition in which at least one of montmorillonite and magnesium carbonate is mixed. The friction transmission belt includes a fabric layer coating at least a surface, of the belt body, making contact with the pulley. The fabric layer has a portion making contact with at least one of the montmorillonite and the magnesium carbonate mixed into the rubber composition.

The present invention pertains to a rubber composition for a transmission belt, the rubber composition comprising: a polymer component including an ethylene--olefin elastomer; carbon black; and clay. The Mooney viscosity of the ethylene--olefin elastomer at 125 C. is 25 ML(1+4)@125 C. or less, and the pH of the clay is 5.5 or higher. The total amount of the carbon black and the clay is 80-180 parts by mass per 100 parts by mass of the polymer component, and the mass ratio of the clay to the carbon black is clay/carbon black=0.2/1 to 1.2/1.

The present invention relates to a toothed belt containing tooth parts that are disposed at predetermined intervals along a belt longitudinal direction, a cord, and a back side that has the cord embedded therein, in which the cord contains a Lang-twisted glass fiber, an adhesion treatment layer, and an overcoat treatment layer, the overcoat treatment layer is formed on a surface of the adhesion treatment layer, the back side is composed of a rubber composition, and the rubber composition contains from 5 parts by mass to 20 parts by mass of a plasticizer based on 100 parts by mass of a rubber component.

The present invention relates to a toothed belt containing tooth parts that are disposed at predetermined intervals along a belt longitudinal direction, a cord, and a back side that has the cord embedded therein, in which the cord contains a Lang-twisted glass fiber, an adhesion treatment layer, and an overcoat treatment layer, the overcoat treatment layer is formed on a surface of the adhesion treatment layer, the back side is composed of a rubber composition, and the rubber composition contains from 5 parts by mass to 20 parts by mass of a plasticizer based on 100 parts by mass of a rubber component.

A power transmission belt has a cord embedded in a belt body made of rubber. The cord is configured as a plied yarn with a total fiber fineness of 4000 to 5000 dtex. The plied yarn consists of four primarily-twisted yarns, each being obtained by subjecting a bundle of para-aramid fibers with a fiber fineness of 1000 to 1250 dtex to a primary twist in one direction at a twist coefficient of 1200 to 1350, and these four primarily-twisted yarns are then secondarily twisted in the opposite direction to the primary twist at a twist coefficient of 900 to 1100, thereby obtaining the plied yarn.

An article such as a power transmission belt includes an elastomeric body and at least one reinforcement cord disposed in the elastomeric body. At least part of the elastomeric body is formed from a rubber compound including styrene butadiene rubber (SBR) sustainable polymer. The rubber compound may include additional sustainable materials, such as one or more of additional sustainable rubber, sustainable fiber, sustainable carbon black, sustainable plasticizers, or the like. The rubber compound may have an overall sustainable content of 50% or greater, or even greater than 65%, such as up to about 95% or more total sustainable content for the rubber compound. The article may include further sustainable material, such as sustainable fabrics and/or sustainable reinforcement cords. The overall article may have a total sustainable content of 50% or greater, or up to about 95% or more total sustainable content for the article.