GB676420A - Improvements in or relating to an emulsion coating composition and method of manufacture thereof - Google Patents

Abstract

A glossy emulsion coating composition comprises a vehicle mixed with a pigment-in-oil, oil-in-water emulsion in which the pigment has been rendered oilophilic. Specified vehicles are dehydrated castor oil fatty acid, pentaerythritol glycerine-phthalic anhydride resin, linseed oil-maleic anhydride resin, and a styrene copolymer emulsion. Driers such as cobalt and lead naphthenate, emulsifying agents such as 2 - amino - 2 - methyl - 1 - propanol and aqueous ammonia, and plasticizers such as tricresyl phosphate may also be present. Titanium dioxide coated with aluminium resinate or with hydrogenated rosin or its sodium salt is the preferred oilophilic pigment.ALSO:A glossy emulsion coating composition is prepared by forming an aqueous dispersion of a pigment, the pigment being rendered oilophilic either before or after dispersion in water, mixing said aqueous dispersion with at least part of the oil vehicle which is to form the discontinuous phase of the fluid emulsion so forming a pigment in oil water-in-oil dispersion, and converting said water-in-oil dispersion to a pigment-in-oil, oil-in-water emulsion. The pigment particles may be coated with an oil-soluble polar organic compound which may be a metallic salt or soap of an organic acid e.g. aluminium resinate. The oil vehicle used for the oil phase is a polar organic compound. The amount of water used for the formation of the initial aqueous pigment dispersion is that required for the final emulsion. A protective colloid such as casein may be present to stabilize the final emulsion while driers such as cobalt and lead naphthenate, emulsifying agents such as 2-amino-2-methyl-1-propanol and aqueous ammonia and plasticizers such as tricresyl phosphate may also be present. Titanium dioxide coated with aluminium resinate or with hydrogenated rosin or its sodium salts, is the preferred oilophilic pigment.