GB991028A - Coating compositions - Google Patents

Abstract

Heat hardenable resin compositions comprise a copolymer of the ester reaction product of a resinous polyhydric alcohol and a drying oil or drying oil fatty acids and 5 to 45% by weight of the copolymer of copolymerizable ethylenically unsaturated monomer comprising a major proportion of methyl methacrylate, and an interpolymer of a carboxylic acid amide containing a CH2=C< group with at least one other ethylenically unsaturated monomer, the interpolymer having amido hydrogen atoms replaced by -ROR1, where R is a saturated C1-8 aliphatic hydrocarbon group having its free valencies on a single carbon atom and R1 is H or C1-8 alkyl. The copolymer may be derived from ester reaction products of linseed, coconut, cottonseed, dehydrated castor, tall, fish or soyabean oils or the acids therefrom and alkyds derived from dicarboxylic acids and alcohols containing at least three hydroxyl groups, e.g. glycerol or pentaerythritol, or copolymers of allyl or methallyl alcohol with styrene, halo or alkyl substituted styrenes or methyl methacrylate. Specified comonomers which may be used in minor proportions are styrene and substituted styrenes, and acrylic and methacrylic esters. The interpolymer may be derived from acrylamide, methacrylamide or itaconic acid diamide and styrene or substituted styrenes, acrylic or methacrylic esters, maleic anhydride, monoesters or diesters or olefins. The interpolymer is modified with an aldehyde, preferably formaldehyde and optionally etherified, e.g. with butanol. In examples, acrylamide is interpolymerized with (1 and 4) styrene and ethyl acrylate, (3) styrene, ethyl acrylate and methyl methacrylate, (5) ethyl acrylate, methyl methacrylate and 2-ethylhexyl acrylate, (6) vinyl toluene and ethyl acrylate and (7) styrene, methyl acrylate and 2-ethylhexyl acrylate, and the interpolymers reacted with formaldehyde in the presence of butanol; glycerol and phthalic acid are reacted with (12) dehydrated castor oil and (18) cottonseed oil, coconut oil and dehydrated castor oil fatty acids, and the products copolymerized with (13) methyl methacrylate and styrene and (16) methyl methacrylate; a styrene-allyl alcohol copolymer is reacted with (19) dehydrated castor oil and the product copolymerized with methyl methacrylate and styrene. The interpolymers and copolymers are admixed with conventional ingredients, e.g. titanium dioxide, talc, silica, solvents such as xylene and butanol and butylated melamine-formaldehyde resins to form enamels.ALSO:Metal substrates, e.g. steel and aluminium, may be coated with heat hardenable resin compositions comprising a copolymer of the ester reaction product of a resinous polyhydric alcohol and a drying oil or fatty acids therefrom and 5-45% by weight of the copolymer of ethylenically unsaturated monomer comprising a major proportion of methyl methacrylate, and an interpolymer of a carboxylic acid amide containing a CH2=C ? group with at least one copolymerizable monomer, said interpolymer having amido hydrogen atoms replaced by -ROR1 where R is a saturated aliphatic hydrocarbon group having its free valencies on a single carbon atom and R1 is H or C1-8 alkyl. The ester reaction product may be derived from a hydroxy polyester or allyl alcohol copolymer and linseed, coconut, cotton-seed, dehydrated castor, tall, fish or soya bean oil or acids therefrom. In examples aluminium strips are coated with high gloss enamels comprising (14) the copolymer of methyl methacrylate and styrene with an ester reaction product of glycerol, phthalic anhydride and dehydrated castor oil, a butylated formaldehyde modified interpolymer of acrylamide, styrene and ethyl acrylate, titanium dioxide and xylene, optionally together with (20) a butanol/xylene solution of a butylated melamine/formaldehyde resin; and a low gloss enamel comprising (15) the above copolymer and interpolymer, a styrene/allyl alcohol copolymer, xylene, talc, titanium dioxide and silica.