GB959133A - Packaging materials - Google Patents

Abstract

Coloured packaging material in the form of sheets or containers made from organic plastics consists of or comprises an organic addition polymer containing a dye linked therewith by a covalent chemical bond. The dye containing addition polymer may be a copolymer of a colourless monomer and a dye containing a polymerizable group, preferably a vinyl group, or may be the reaction product of a polymer containing reactive groups and a dye having a group reactive therewith, and may be prepared by the processes described in Specifications 622,935, 877,402 and 946,472. Innocuous plasticizers, fillers and pigments may be incorporated and sheets prepared by casting from solution, aqueous dispersion or a melt. Bags, bottles, beakers, boxes and tubes may be prepared by injection moulding, and the polymers may be laminated to or used for impregnating paper or cardboard. The sheets and containers may be used for packaging solid and liquid foodstuffs, pharmaceuticals, tinctures, cosmetic preparations and chemical reagents and solvents. In examples (1) sheets are calendered from a copolymer prepared by suspension copolymerization of vinyl chloride and N-acryloylaminoazobenzene in the presence of partially saponified polyvinyl acetate, azodiisobutyronitrile and sodium pyrophosphate; and (2) boxes are obtained by deep drawing sheets extruded from a mixture of a suspension copolymer of styrene and acrylonitrile and a copolymer obtained by initiating the copolymerization of vinyl methyl ether and the product obtained by coupling N-acryloylamino-p-aminobenzene and 1-(2-chloro-5-sulphophenyl) -3- methyl-pyrazolone -5, in aqueous dispersion in the presence of sodium paraffin sulphonates, potassium persulphate, sodium bicarbonate and sodium pyrophosphate, and adding butyl acrylate, acrylonitrile and butane diol diacrylate when polymerization has commenced.