GB1056798A - Improvements in the bonding of synthetic textile fibres to rubber - Google Patents

Abstract

A composition suitable for treating synthetic textile fibres, e.g. polyester and polyamide fibres, to improve their bonding to rubber compositions comprises an aqueous dispersion or emulsion of a masked isocyanate which upon heating generates free isocyanate groups, an epoxy resin and a rubber latex. Suitable masked isocyanates are phenol-blocked metaphenylene diisocyanate, phenol blocked triphenyl methane triisocyanate and phenol-blocked methylene-bis(-4-phenylisocyanate) and the epoxy resin may be epoxidized polybutadiene or the reaction product of bisphenol A and epichlorhydrin. The rubber latex may be a natural rubber latex or a synthetic rubber latex, e.g. a copolymer of butadiene with a vinyl compound such as styrene, or a terpolymer of butadiene, styrene and vinyl pyridine. The aqueous dispersion or emulsion may have a solids content of 10-25% by weight. The ratio of the weight of the masked isocyanate to the weight of the latex may vary from 10:1 to 0.2:1. The amount of the epoxy resin may be equal to or less than the amount of the masked isocyanate. The aqueous dispersion or emulsion may also contain paraformaldehyde. The dispersion or emulsion may be prepared by mixing the various constituents together in the presence of an emulsifying agent, e.g. soaps, alkyl arylsulphonates and polyether alcohols, and a small proportion of an organic solvent, e.g. methylene chloride and chloroform. missing page 154ALSO:Improved bonding of synthetic textile fibres, e.g. polyester and polyamide fibres, to rubber is obtained by coating the fibres by passing them through an aqueous dispersion or emulsion of a masked isocyanate which upon heating generates free isocyanate groups, an epoxy resin and a rubber latex. Suitable masked isocyanates are phenol-blocked meta-phenylene diisocyanate, phenol blocked triphenyl methane triisocyanate and phenol-blocked methylenebis(-4-phenylisocyanate) and the epoxy resin may be epoxidized polybutadiene or the reaction product of bisphenol A and epichlorohydrin. The rubber latex may be a natural rubber latex or a synthetic rubber latex, e.g. a copolymer of butadiene with a vinyl compound such as styrene or a terpolymer of butadiene, styrene and vinyl pyridine. The aqueous dispersion or emulsion may have a solids content of 10-25% by weight. If the textile fibre is in the form of a monofilament the dispersion preferably contains the masked isocyanate and rubber latex in a weight ratio of 8.5:1 and if the textile fibre is in the form of a cord the ratio may be 0.3:1. The ratio of the weight of the masked isocyanate to the weight of the latex may however vary from 10:1 to 0.2:1. The amount of the epoxy resin may be equal to or less than the amount of the masked isocyanate. If the fibres are in the form of tyre cords the aqueous dispersion or emulsion may also contain paraformaldehyde. The dispersion or emulsion may be prepared by mixing the various constituents together in the presence of an emulsifying agent, e.g. soaps, alkyl arylsulphonates and polyether alcohols, and a small proportion of an organic solvent, e.g. methylene chloride and chloroform. The fibres may be treated at room or elevated temperatures and then dried first at room temperature and, then at a higher temperature. They may then be provided with a thin coating of a rubber composition, made up into articles, e.g. tyres, driving and conveyor belts, hose, tarpaulines, containers for liquids or solids or life rafts, and vulcanised.