GB1361634A - Pressure-sensitive transfer elements - Google Patents

Abstract

1361634 Pressure-sensitive transfer material KONTOR KEMI AS T PELLE J V ANDERSEN and W POPIOLEK 7 Sept 1972 [7 Sept 1971] 41698/71 Heading D2B A pressure sensitive transfer element is produced by a process which comprises applying a transfer composition containing a compound having reactive hydrogen atoms to a flexible substrate provided with a whole or partial coating containing an organic polyisocyanate, the coating having available free isocyanate groups which react with the compound having reactive hydrogen atoms so as to bond the transfer composition to said coating, the coating constituting an intermediate layer between the substrate and the transfer composition. The flexible substrate may be high density polyethylene, polypropylene, copolymers of ethylene and propylene, polycarbonates, polyesters and paper. The polyolefins may be oriented and surface oxidised. The polyisocyanate can be toluene diisocyanate or an isocyanate containing polyurethane prepolymer and the coating may contain anti-tack agents e.g. solid polymers, resins and waxes. The transfer composition can be wax-based containing waxes such as Carnauba or Montan wax wool grease and brassicoil, and containing where necessary to provide reactive hydrogen atoms polyoxyethylene waxes, or wax less containing binders such as polyvinyl acetate, polyvinylformal, polyvinyl acetal, polycarbonates, vinyl chloride/ vinyl acetate copolymers and polyvinyl chloride and where necessary alcohols, polyvinylalcohol, primary or secondary amines, polyamines, polycarboxylic acids and alkyd resins to provide reactive hydrogen atoms. The transfer composition may be provided with a top coating. The polyisocyanate composition may contain polyvinyl formal, chlorinated PVC and styrene/ isoprene block copolymer.