GB646945A - Coating compositions - Google Patents

Abstract

Cellulose propionate containing 0.1 to 0.5 hydroxyl groups per glucose unit and having a viscosity of 10 to 100 centipoises is mixed with 40 to 100 per cent of its own weight of a solvent plasticizer therefor, or of a mixture of one part by weight of a non-solvent plasticizer therefor with at least three parts by weight of a solvent plasticizer to give a hot-melt coating composition. The compositions give a heat-sealing, water-resistant, non-tacky coating on wood, paper, textile materials and metal. Suitable solvent plasticizers are dibutyl sebacate, dioctyl sebacate, dioctyl azelate, dibenzyl sebacate, tricresyl phosphate and p-ethyl toluene sulphonamide. Suitable non-solvent plasticizers are butyl stearate, butoxyethyl stearate, amyl oleate and partially hydrogenated terphenyls. Coatings containing a non-solvent plasticizer in amount up to 10 per cent of the total plasticizer are transparent, those containing 10-25 per cent being translucent. Light stabilizers such as phenyl salicylate and heat stabilizers such as calcium lactate may be added in amounts from 0.5 to 5 per cent by weight of the cellulose propionate. Pigments, dyes, effect materials may also be incorporated in the compositions. In an example (all parts are by weight), 100 parts of cellulose propionate containing 0.3 hydroxyl groups and of viscosity 50 centipoises, are mixed with 90 parts of dibutyl sebacate and 10 parts butoxyethyl stearate and the molten mixture coated on to an absorbent paper base, to give a smooth non-tacky hard coating impermeable to moisture. Other examples describe compositions comprising (2) 100 parts of cellulose propionate (0.15 hydroxyl, 10 centipoises), 100 parts of dioctyl sebacate and 5 parts calcium lactate; (3) 100 parts of cellulose propionate (0.5 hydroxyl, 75 centipoises) and 100 parts of dioctyl azelate; and (4) 100 parts of cellulose propionate (0.4 hydroxyl, 25 centipoises) and 50 parts of a mixture of 75 parts tricresyl phosphate and 25 parts partially hydrogenated isomeric terphenyls. Specification 639,961 is referred to.