Vinyl polymer polyepoxy coating composition

摘要

Coating compositions particularly suitable for coating leather comprise an aqueous dispersion of (1) a water-insoluble polymer containing tertiary amine groups; (2) an epoxide polymer containing at least two epoxy groups per mol., having the formula (3), (4), (5) or (6) shown below. The water-insoluble polymers containing tertiary amine groups are obtained from (1) monovinyl pyridines, e.g. 2-vinyl-, 3-vinyl-, 4-vinyl-, 2-methyl-5-vinyl-, 5-methyl-2-vinyl-, 2,3,4-trimethyl-5-vinyl-pyridines etc.; (2) compounds of the general formula CH2=C(R)AYNR1R11 where R is H or CH3, A is O, S, -CO- or -C-NH-, Y is an alkylene group of 2-8 C atoms, R1 when not directly attached to R11 is phenyl, methylbenzyl, benzyl, cyclohexyl or alkyl having 1-6 C atoms, R11 when not directly attached to R1 is the same as R1, while R and R11 when directly connected together are morpholino, piperidino, or pyrrolidino residues. Examples are 2-dimethyl aminoethyl acrylate, methylacrylate, vinyl ether or sulphide or acrylamide and similar morpholino, piperidino and pyrrolidino derivatives. The epoxy polymers have the general formul where #f is the para-phenylene group. As the polymers should be water-insoluble it is necessary that when some of the vinylpyridines which form water-soluble polymers are used these shall be copolymerized with at least one other copolymerizable monoethylenicallyunsaturated monomer which will render the copolymers insoluble in water. The polymers may be polymerized in presence of suitable anionic, cationic or non-ionic dispersing agents, long lists of which are given in the Specification, and at temperatures from 0-100 DEG C. in the presence of peroxide free-radical catalysts of the "Redox" type. The epoxy condensate is preferably introduced into the aqueous dispersion of the tertiary amine containing polymer after completion of polymerization though it may be introduced during polymerization; amounts from 1-90 per cent based on the weight of the t-polymer may be used; preferably equivalent amounts of amine and epoxy groups are employed. Pigments are introduced into the composition with the aid of dispersing agents and in the presence of protective colloids, e.g. methyl cellulose, polyvinyl alcohol alginates &c. Pigments specified are red iron oxide, chrome green molybdate, chrome orange titanium dioxide, lithopone, chrome yellow, ultramarine blue, red cadmium, yellow cadmium, organic tones or lake, phthalocyanines. In a modification the t-amine polymer is applied to the leather as a separate coating followed by further coatings which may be lacquers of any suitable composition, e.g. film-forming compositions containing nitrocellulose or cellulose organic esters or vinyl or acrylic polymers and the epoxy compound is added dispersed in one or more of these coatings. In an example: (a) a copolymer obtained by copolymerizing a mixture of ethyl acrylate, butylacrylate and vinyl pyridine in presence of ammonium persulphate, sodium hydrosulphite and triethanolamine as catalyst is pigmented with a dispersion of red iron oxide in water, sodium lauryl sulphate, t-octylphenoxypolyethoxyethanol and methyl cellulose and the pigmented dispersion is used to swab leather upholstery. The dried coating is then further coated with a pigment dispersion consisting of red iron oxide, a plasticiser obtained by reacting sebacic acid with propylene glycol, and a vinyl chloridevinyl acetate copolymer in a solvent mixture comprising ethoxyethyl acetate, methyl ethyl ketone, and a mixture of aromatic, naphthenic and aliphatic hydrocarbons, the pigment dispersion also containing an epoxy compound of formula III above; (c) the leather is then given a final coating by spraying it with a vinyl chloride-vinyl acetate copolymer in a solvent mixture comprising ethyoxyethyl acetate, methyl ethyl ketone and xylene.