Patent GB-986921-A (GB)
Title: Condensation products and coating compositions based thereon
IPC: C08L61/20
Filed: 1961-05-10
Abstract: A coating composition comprises a solution in an organic solvent of either (A) a condensation product obtained by heating a solution in an organic solvent of a mixture of (1) 15 to 60% by weight of butylated polymethylol melamine resin-forming condensate, and (2) 85 to 40% by weight of a copolymer of a mixture of copoly-merizable monoethylenic monomers comprising as the sole alcoholic hydroxy monomer 5 to 30% by weight of an ester of the formula CH2=C(R)COOR1OH wherein R represents hydrogen or methyl and R1 represents a C2 or C3 alkylene group, the solution of the mixture being heated at a temperature of 50 DEG  to 140 DEG  C. for at least 1/2 hour, but short of the period resulting in gelation, until the solution clears and is capable of forming a clear film on baking at 150 DEG  C. for 1/2 hour, or (B) a reaction product obtained by copoly-merizing, at a temperature 50 DEG  to 140 DEG  C. for at least 8 hours, but short of the period resulting in gelation, until the product forms a clear film on baking at 150 DEG  C. for 1/2 hour, a mixture of copolymerizable monoethylenic monomers comprising as the sole alcoholic hydroxy monomer 5 to 30% by weight of an ester as defined above, in a solution containing a butylated polymethylol melamine resin-forming condensate and a free-radical polymerization initiator, the amount of condensate being from 15 to 60% by weight of the total weight of condensate and monomers, and the amount of free-radical initiator being from 1/2 to 3% by weight of the monomers.  Preferred copolymers are those of hydroxyethyl and hydroxypropyl acrylates and methacrylates with comonomers such as acrylic and methacrylic acids and their esters and nitriles, styrene, vinyl toluene alpha-methyl-styrene, and maleic, fumaric, aconitic, citraconic, itaconic and crotonic acids.  Suitable reaction solvents are aromatic hydrocarbons, esters, ketones, alcohols, ethers, nitroalkanes, dimethyl formamide and acetamide, and acetonitrile. Benzoyl peroxide is specified as a polymerization initiator.  In examples of process (A) there are described the reaction of a butylated polymethylol melamine condensate with solution copolymers of:  (1) and (2) betahydroxypropyl methacrylate methyl methacrylate, ethyl acrylate, sturene and itaconic acid, (5) as in (1) but with the methyl methacrylate replaced by styrene, (6) beta-hydroxyethyl methacrylate, ethyl acrylate and methacrylic acid, and (7) beta-hydroxyethyl methacrylate, methyl methacrylate, ethyl acrylate, styrene and methacrylic acid.  In examples of process (B) a butylated polymethylol melamine condensate is present during the solution copolymerization of (3) the monomers as in (1), and (4) beta-hydroxyethyl methacrylate, methyl methyacrylate and ethyl acrylate. Specification 939,211 is referred to.ALSO:Surfaces of wood, glass, ceramics, brick, stone, concrete and metals are coated with a composition comprising a solution in an organic solvent of either (A) a condensation product obtained by heating together in an organic solvent a mixture of a butylated polymethylol melamine resin-forming condensate and a copolymer of a mixture of monomers comprising 5-30% by weight of hydroxyethyl or hydroxypropyl acrylate or methacrylate, or (B) a reaction product obtained by copolymerizing a mixture of monomers comprising 5-30% by weight of hydroxyethyl or hydroxypropyl acrylate or methacrylate in a solution containing a butylated polymethylol melamine resinforming condensate.  Comonemers for use in the copolymers are acrylic and methacrylic acids and their esters and nitriles, styrenes and maleic, fumaric, aconitic, citraconic, itaconic and crotonic acids.  Suitable solvents are aromatic hydrocarbons, esters, ketones, alcohols, ethers, nitroalkanes, dimethyl formamide and acetamide and acetonitrile. Also present in the compositions may be pigments.  The examples describe the application to glass surfaces of compositions of the above types in which the copolymers are derived from beta-hydroxyethyl or beta-hydroxypropyl methacrylate with one or more comonomers selected from methyl methacrylate, ethyl acrylate, styrene, methacrylic acid and itaconic acid.  Specification 939,211 is referred to.