GB1459841A - Aqueous polymer blends - Google Patents

Abstract

1459841 Aqueous polymer blends UNION CARBIDE CORP 29 April 1974 [30 April 1973] 17096/74 Headings C3R and C3P [Also in Division B2] An aqueous mixed dispersion comprises (a) an addition polymer having film forming properties comprising polymer particles dispersed in water in latex form; and (b) a thermosetting resole formed by the alkaline-catalyzed condensation of a phenol and an aldehyde, having a weight average M.Wt. of 300-3000, and comprising solid particles suspended in water, substantially all of which have diameters of less than 60 microns; wherein the addition polymer is a homo- or co-polymer of at least one of vinyl chloride, vinyl acetate, vinyl alcohol, alkyl acrylate, alkyl methacrylate, butadiene, chloroprene, styrene, ethylene, acrylic acid, methacrylic acid, acrylamide, acrylonitrile, itaconic acid, maleic acid, N-methylolacrylamide, gammahydroxypropyl acrylate, betahydroxyethyl acrylate, neopentyl glycol diaacrylate or glycidyl acrylate. The dispersions preferably contain on a solids basis from 3-90% wt. of the phenolic resin and 10-97% wt. of the addition polymer. Suitable phenols include phenol, m-substituted C 1 -C 9 alkyl, alkoxy or halophenols and bisphenols. The phenolic dispersion may be prepared by carrying out the condensation in the presence of a mixture of gum arabic and at least one polysaccharide gum having mannose and galactose units or D- mannuronic acid and L-guluronic acid units. Suitable polymer latices include those of polyvinylchloride, polyvinylacetate, polyacrylates, polybutadiene, polychloroprene, polystryene and numerous copolymers. The addition polymers may contain up to 20% wt. of functional groups which will react with the phenolic resole resin, e.g. carboxyl, alcoholic hydroxyl, e.g. methylol, sulfonamido, amino or amido groups. In the examples aqueous dispersions are prepared from (1) a latex of either polyvinylacetate or a copolymer of styrene, ethyl acrylate, acrylonitrile, N-methylol acrylamide and acrylic acid, and (2) a phenolic dispersion prepared by the alkaline condensation of phenol and HCHO in the presence of gum arabic and either guar gum or a gum comprising galactose units, and are cured by heating. Aqueous dispersions for use as contact adhesives are also prepared from (1) either (i) a latex copolymer (A) of ethyl acrylate, acrylonitrile, acrylic acid and N- methylol acrylamide alone or in admixture with an acrylate latex copolymer (B) of vinyl acetate and isobutyl acrylate, or (ii) an acrylate latex prepared by adding an aqueous dispersion of a copolymer of ethylene and acrylic acid partially neutralized with N,N-dimethylolethanolamine to an acrylate copolymer latex of ethyl acrylate, methyl methacrylate and methacrylic acid and then heating, alone or in admixture with acrylate latex (B), and (2) either a bisphenol A-HCHO resin dispersion (C) prepared in the presence of gum arabic and Jaguar (R.T.M.) gum or the phenol-HCHO resin dispersion described above. Primer compositions comprising the inventive aqueous dispersion are prepared from (i) a latex copolymer of styrene, ethyl acrylate, acrylic acid and optionally neopentyl glycol diacrylate, and (ii) either a bisphenol A-HCHO resin dispersion similar to (C) above or a phenolic dispersion prepared from bisphenol A, t-butylphenol and HCHO in the presence of gum arabic and "Jaguar" gum, and (iii) CH 3 COO(CH 2 CH 2 O) 2 CH 2 CH 3 and optionally TiO 2 pigment, zinc phosphate and a defoamer. The primers are cast on to phosphated steel and cured and then overcoated with a white pigmented thermosetting acrylic resin and rebaked.