GB600999A - Printed sheet materials - Google Patents

Abstract

A sheet of polythene supported on a backing is printed while molten with a mixture comprising one or more dyes and/or pigments and a material capable of forming a solid solution with polythene, the mixture having a softening temperature lower than that of the molten sheet. Suitable materials are polystyrene, hydrogenated polystyrene, polythene, pyrolysis products of polythene, chlorinated polythene, polyisobutylene, rubber, cyclised rubber, Neoprene, butyl rubber, guttapercha, gum elemi, ester gum, hydrogenated ester gum, hydrogenated castor oil, paraffin, micro-crystalline wax, ozokerite, carnauba, ceresin, montan and bees wax, chlorinated naphthalene and diphenyl, asphalt, polypropylene, polypropylene sebacate, polyvinyl isobutyl ether. Suitable dyes are the wax-soluble "Waxoline" (Registered Trade Mark) dyes. The printing mixture may be applied cold, hot or dissolved in hydrocarbon, e.g. xylene, or chlorinated hydrocarbon solvents. The backing may be a polished metal roller or band and may be coated with separating aids such as a high melting-point grease, aluminium or zinc stearate, sodium silicate or a detergent, or paper or fabric. Preferably the sheet is solidified immediately after printing by chilling with the printing plate or roller. The polythene sheet may be heated to the molten state by hot rollers or infra-red heaters. Polythene coatings on fibrous materials made as described in Specification 600,687, [Group VIII], may be printed before the coating has cooled from the molten state. Sheets formed by the process of Specification 567,358 may be printed during their formation. In the example the inking roller is made of "Welvic" (Registered Trade Mark) and the transfer roller is of steel.