GB802342A - Coating compositions - Google Patents

Abstract

Hammer finishes are obtained by coating with a composition comprising (1) an organic film-forming coating resin or polymer other than (3), (2) a metallic pigment in an amount from 0.5-100 p.b.w. per 100 p.b.w. of (1) and (3) 0.01-2 p.b.w. per 100 p.b.w. of (1) of a benzene-soluble organopolysiloxane of at least 50,000 cs. viscosity at 25 DEG C. and having on the average 1.99-2.01 monovalent hydrocarbon radicals per Si, at least 50 per cent of the polymer units being RMeSiO, where R is an aliphatic hydrocarbon radical of less than 4C and any remaining polymer units being <FORM:0802342/III/1> where R1 is a monovalent hydrocarbon radical and n is 1-3. (1) may be synthetic resins or cellulose derivatives (see Group IV (a)), chlorinated or natural rubber (see Group V), natural resins, shellac or drying oils. (2) may be finely-divided Al, Cu, Ni, Cr or bronze, in leafing or non-leafing form. In (3) the R may be methyl, ethyl, propyl, vinyl or allyl and R1 may be methyl, ethyl, propyl, octadecyl, vinyl, allyl, hexenyl, cyclohexyl, cyclohexenyl, benzyl, phenyl, tolyl, xenyl or naphthyl. Optional ingredients include pigments (metal oxides, carbon black, copper phthalocyanine, toluidine red), conventional solvents and fume silica. The coatings may be applied by brushing, dipping or spraying to metals (steel panels), wood, paper, ceramics, or organic resins, and air dried or baked. In Example 1 an air-drying hammer finish comprising 5 p.b.w. non-leafing Al powder, 100 p.b.w. linseed oil and 0.03 p.b.w. of a polysiloxane gum (95 mol. per cent dimethyl + 5 mol. per cent phenyl methyl) in xylene dispersion of 72 per cent polysiloxane to 28 per cent fume silica was sprayed on steel panels.ALSO:Hammer finishes are obtained by coating with a composition comprising (1) an organic film-forming coating resin or polymer other than (3). (2) a metallic pigment in an amount from 0.5-100 p.b.w. per 100 p.b.w. of (1) and (3) 0.01-2 p.b.w. per 100 p.b.w. of (1) of a benzene-soluble organopolysiloxane of at least 50,000 cs. viscosity at 25 DEG C. and having on the average 1.99-2.01 monovalent hydrocarbon radicals per Si, at least 50 per cent of the polymer units being RMeSiO, where R is an aliphatic hydrocarbon radical of less than 4 C. and any remaining polymer units being R1nSiO 4-n/2 where R1 is a monovalent hydrocarbon radical and n is 1-3, (1) may be cellulose derivatives (e.g. ethyl, nitrate, acetate, butyrate), phenolaldehyde resins (linseed oil modified), ureaformaldehyde, alkyds (glycerine/unsaturated polycarboxylic acids, terephthalic/pentaerythritol, or phthalic/glycerine which may be linseed, coconut or soya bean oil modified), epoxy resins (epichlorhydrin/bis-phenol), melamine-formaldehyde, fatty acid modified polyurethanes, terpene phenolic resin,s coumaroneindene, styrenated alkyds (styrenated linseed oil glycerine phthalic), vinyl resins (acetate, chloride, acetate/chloride, butyral, acetate/vinylidene chloride, acetate/alcohol), acrylonitriles, acrylic esters (methyl acrylate, butyl or methyl methacrylate), silicones (methylphenyl), modified silicones (alkyds, phenolics, epoxies, aminoplasts) chlorinated or natural rubber, or mixtures thereof; (2) may be finely divided Al, Cw, Ni, Cr or bronze, in leafing or non-leafing form. In (3) the R may be methyl, ethyl, propyl, vinyl or allyl and R1 may be methyl, ethyl, propyl, octadecyl, vinyl, allyl, hexenyl, cyclohexyl, cyclohexenyl, benzyl, phenyl, tolyl, xenyl or naphthyl. Optional ingredients include pigments (metal oxides, carbon black) solvents, e.g. hydrocarbons (xylene), esters (dibutyl phthalate), ketones (methyl ethyl and methyl isobutyl), ethers (ethylene glycol monoethyl), alcohols, chlorinated hydrocarbons and organic pigments (Cw phthalocyanine, toluidine red) and fume silica. The coatings may be applied by brushing, dipping or spraying to metals (steel panels), wood, paper, ceramics or organic resins, and air dried or baked.