Patent GB-1062286-A (GB)
Title: Stoving lacquers
Inventor: WILHELM HANS
IPC: C08F212/06
Filed: 1964-06-26
Abstract: Stoving lacquers comprise organic solvent solutions of copolymers of (a) 30 to 87.5% by weight of a mixture of (1) 10 to 90% by weight of at least one acrylic or methacrylic acid ester of a C1- 10 alkanol and (2) 10 to 90% by weight of styrene or an alkylstyrene having 1 to 3 carbon atoms in the alkyl group or a mixture of such styrenes; (b) 10 to 45% by weight of at least one ether of N-methylol-acrylamide or -methacrylamide with an alkanol, oxaalkanol or phenylalkanol having 1 to 8 carbon atoms in the alkane radical; (c) 2 to 15% by weight of at least one mono-ester of acrylic or methacrylic acid with an alkanediol or 3-oxaalkanediol having 4 to 6 carbon atoms and exclusively terminal hydroxyl groups; (d) 0.5 to 10% by weight of acrylic and/or methacrylic acid, and optionally (e) up to 20% by weight of one or more other ethylenically unsaturated copolymerizable compounds, the sum of the percentages of components (1) and (2) being 100 and of components (a) to (e) being 100.  Specified monomers (e) are acrylonitrile, esters of acrylic or methacrylic acid with alkanols having more than 10 and up to about 20 carbon atoms, acrylamide, methacrylamide, maleic acid, fumaric acid, vinyl acetate, vinyl butyrate, vinyl isobutyl ether, vinyl chloride and vinylidene chloride.  Suitable organic solvents are, for example, toluene, xylene, n- or isobutanol, butanediol-1,4, ethylene glycol monomethyl ether, ethyl acetate and ethylene glycol monomethyl ether monoacetate, and mixtures of such with each other or with gasoline hydrocarbons. Optional ingredients include pigments, e.g. titanium dioxide, soluble dyes, optical brighteners, agents for promoting flow and gloss, and binders such as alkyd resins, aminoplast or phenoplast resins, e.g. formaldehydemelamine, epoxy resins, e.g. from 2,2-bis-(p-hydroxyphenyl) - propane and 1 - chloro - 2,3-epoxypropane, colophony resins, drying or non-drying oils, cellulose derivatives and other polymers.  The copolymers are preferably prepared by solution polymerization of the corresponding monomers in a solvent as set forth above using as initiators, azo compounds, peroxy compounds or peroxy compounds in admixture with sulphinic acids or heavy metal compounds; regulators such as mercaptans or aldehydes may be present.  In the examples, polymerization is effected with azodiisobutyronitrile or cumene hydroperoxide in the presence of t-dodecyl mercaptan, the catalyst being added during the course of polymerization. The stoving lacquers are suitable for application to metals, and may be stoved in the presence of an acidic compound in order to cure the copolymer.ALSO:Stoving lacquers comprise organic solvent solutions of copolymers of (a) 30 to 87.5% by weight of a mixture of (1) 10 to 90% by weight of at least one acrylic or methacrylic acid ester of a C1-10 alkanol and (2) 10 to 90% by weight of styrene or an alkylstyrene having 1 to 3 carbon atoms in the alkyl group or a mixture of such styrenes, (b) 10 to 45% by weight of at least one ether of N-methylolacrylamide ormethacrylamide with an alkanol, oxaalkanol or phenylalkanol having 1 to 8 carbon atoms in the alkane radical, (c) 2 to 15% by weight of at least one mono-ester of acrylic or methacrylic acid with an alkanediol or 3-oxaalkanediol having 4 to 6 carbon atoms and exclusively terminal hydroxyl groups, (d) 0.5 to 10% by weight of acrylic and/or methacrylic acid, and optionally (e) up to 20% by weight of one or more other ethylenically unsaturated copolymerisable compounds (preferably acrylonitrile), the sum of the percentages of components (1) and (2) being 100 and of components (a) to (e) being 100.  Suitable organic solvents are, for example, toluene, xylene, n- or iso-butanol, butanediol-1,4, ethylene glycol monomethyl ether, ethyl acetate and ethylene glycol monomethyl ether monoacetate, and mixtures of such with each other or with gasoline hydrocarbons.  The stoving lacquers are particularly suitable for application to metals, e.g. iron, aluminium and magnesium or alloys thereof, which may be in the form of sheet metal, vehicle bodies, ships, washing machines or refrigerators. They may be applied by spraying or immersion and stoved at temperatures from 120 DEG  to 180 DEG C.  Stoving may be effected in the presence of a hardener, which is generally an acidic compound. The stoving lacquers may contain as optional ingredients pigments, e.g. titanium dioxide, soluble dyes, optical brighteners, agents for promoting flow and gloss, and binders such as alkyd resins, aminoplast or phenoplast resins, epoxy resins, colophony resins, drying or non-drying oils, cellulose derivatives and other polymers.