Patent GB-935292-A (GB)
Title: Improvements in or relating to coating compositions
IPC: C09D5/08
Filed: 1960-04-06
Abstract: A coating-composition is prepared by forming an aqueous solution of an organic protective colloid stabilizing agent, dispersing therein a viscous coating material in the form of particles at least 90% of which have at least one dimension greater than 50 microns, and thereafter dispersing additional organic protective colloidal material in amount such that the viscosity of the composition is at least 65 Krebs units, without substantially decreasing the particle size.  The dispersion of viscous coating material is prepared as in Specification 750,605 and the incorporation of the additional colloidal material is effected by agitation over a comparatively short period of time, e.g. of 1 to 3 minutes using a propeller type mixer, at about 150 to 350 r.p.m.  Suitable additional colloidal materials are methyl-, hydroxyethyl- and carboxymethylcellulose, glue, dextrin and casein, and these are added as aqueous solutions or in admixture with synthetic resin emulsions or paints containing, e.g. polyvinyl acetate, polyvinyl propionate, butadiene-styrene copolymers or polyacrylates.  The resulting compositions are suitable for application by paint-rollers.  In examples, differently coloured nitrocellulose lacquers are dispersed successively in aqueous methyl cellulose solutions, and to the resulting base compositions are added with mild agitation (I) a paint comprising potassium tripolyphosphate, a nonfoaming wetting agent, methyl cellulose, tap water, rutile titanium dioxide and plasticized polyvinyl acetate emulsions; (II) a 2% methyl cellulose solution in water; (III) polyvinyl priopionate dispersion and a 1% aqueous solution of methyl cellulose; (IV) a 37,5% solution of dextrin in water.ALSO:A coating composition is prepared by forming an aqueous dispersion of an organic protective colloid stabilizing agent, dispersing therein a viscous coating material in the form of particles at least 90% of which have at least one dimension greater than 50 microns, and thereafter dispersing additional organic protective colloidal material in an amount such that the viscosity of the composition is at least 65 Krebs units, without substantially decreasing the particle size.  The dispersion of viscous coating material is prepared as in Specification 750,605. Suitable additional colloidal materials are methyl-, hydroxyethyl- and carboxymethyl-cellulose, dextrin and casein, and these are added as aqueous solutions or in admixture with synthetic resin emulsions or paints containing, e.g. polyvinyl acetate, polyvinyl propionate, butadiene-styrene copolymers or polyacrylates.  In examples, differently coloured nitrocellulose lacquers are dispersed successively in aqueous methyl cellulose solutions, and to the resulting base compositions are added with mild agitation (I) a paint comprising potassium tripolyphosphate, a non-foaming wetting agent, methyl cellulose, tap water, rutile titanium dioxide and plasticized polyvinyl acetate emulsions; (II) a 2% methyl cellulose solution in water; (III) polyvinyl propionate dispersion and a 1% aqueous solution of methyl cellulose; (IV) a 37,5% solution of dextrin in water.