GB1148162A - Stove Lacquers - Google Patents

Abstract

1,148,162. Aqueous alkyd-aminoplast coating compositions. VVB LACKE UND FARBEN. 9 March, 1966, No. 10325/66. Heading C3R. [Also in Division B2] A coating composition consists of (a) an alkyd resin of Acid No. above 60 and below 100 and OH No. between 75 and 150; (b) a basic nitrogen compound which forms a water-soluble soap with (a); (c) a water-soluble, heat-hardenable melamine-formaldehyde condensate containing at least 4 methylol groups per mole of melamine, more than half of which are etherified to methoxymethyl groups; (d) water; and optionally (e) 0 to 35% by wt. of (a)+(c) of an at least partially water-miscable organic solvent compatible with (a) and (c); (f) a pigment; and (g) a wetting agent. The weight ratio of (a) : (c) is between 95 : 5 and 60 : 40. Preferred orders and conditions for blending the ingredients are given. The alkyd (a) may be modified with a C 7-22 unsaturated monocarboxylic or a resin acid, (b) may be a t-aliphatic amine, t-alkylolamine or t-alkylol-alkyl amine. The solvent (e) may be an alcohol, keto-alcohol or monoalkyl ether of glycol. In the examples the alkyds have Acid Nos. 68À5, 70 and 72 and OH Nos. 145, 128 and 123 respectively; (b) is triethylamine; (c) is hexamethoxymethylmelamine; (e) is glycol monobutyl ether, plus butanol in Example 3; and (f) is TiO 2 . Carbon pigments may also be used. The compositions may be used to spray or dip-lacquer metal objects, e.g. steel sheets, and the coatings stoved, e.g. at 150‹ C. for 30 minutes. In Example 3, 0À5% by wt. of (a) + (b) of p-toluene-sulphonic acid is incorporated before spraying.