Toothed belt
Described herein is a toothed belt comprising a body made of elastomeric material, in which there is embedded a plurality of longitudinal filiform resistant inserts or cords, and a toothing coated with a coating fabric; on top of the coating fabric there is made to adhere a resistant layer, which increases resistance to wear of the toothed belt and comprises a fluorine-based plastomer with addition of elastomeric material, in which the plastomer is present in a larger amount than is the elastomeric material and in which the majority of the particles constituting the fluorine-based plastomer have a size less than 10 μm. The resistant layer is applied directly on the fabric via spreading. The fluorinated plastomer preferably has a base of polytetrafluoroethylene compound.
1. A process for fabrication of a toothed belt, comprising:
forming an elongate belt body of a first elastomeric material, the belt having a first, planar side and a second side opposite the first side;
forming teeth along the second side;
coating the teeth with a fabric of a polymeric material;
treating the fabric with a liquid solution of RFL to impregnate fibres of the fabric;
coating the treated fabric with a resistant layer comprising a fluorinated plastomer and a second elastomeric material, the fluorinated plastomer being present in the resistant layer in an amount between 101 and 150 parts by weight of an amount of the elastomeric material and containing more than 50% of particles of a size smaller than 10 μm; and
directly adhering the resistant layer to the fabric coated over the teeth, wherein the resistant layer is applied directly to the fabric via spreading a weight of the fluorinated plastomer and second elastomeric material between 50 and 80 g/m 2 to produce a uniform thickness resistant layer on the treated fabric.
2. A process according to claim 1 in which forming the elongate belt body includes embedding a plurality of longitudinal filiform resistant inserts or cords in the first elastomeric material.
3. A process according to claim 1 , characterized in that said second elastomeric material comprises HNBR.
4. A process according to claim 1 , characterized in that said fluorinated plastomer is polytetrafluoroethylene.
5. A process according to claim 4 , characterized in that said second elastomeric material comprises HNBR.
6. A process according to claim 5 , characterized in that said second elastomeric material comprises HNBR modified with a zinc salt of polymethacrylic acid.
7. A process according to claim 1 , characterized in that the resistant layer thickness is from 30 and 50 micrometers.