| 摘要 |
A soluble product which is convertible into the insoluble state by polyesterification is prepared by mixing or partly esterifying (I) an addition compound of 1 p.b.w. of maleic anhydride with 1.5-2.5 or, in the presence of amine (see below), 3.0 p.b.w. of an unsaturated oil fatty acid, or a hydroxy-free polyol ester thereof, containing only isolated double bonds or one pair of conjugated double bonds, with (II) a diol in amounts approx. equivalent to the carboxyl or anhydride groups of I. Preferred oils have iodine values of 120-170 cg. I/g. From 3-7% by weight of the addition compound of a primary or secondary amine of low volatility may be used in place of part of the diol. Suitable diols are diprimary glycols, e.g. ethylene or polyethylene glycols or butane-1,4-diol; less preferred are e.g. a propane-1,2-diol, butane-2,3-diol, dipropylene glycol, and fatty acid monoesters of triols, e.g. of glycerol and trimethylolpropane; dimethylol alkylphenols may also be used in minor amounts. Suitable amines are e.g. ethylene diamine or polymers thereof, and amine diols, e.g. diethanolamine. The soluble product may be obtained by heating (I) and (II) together at about 100 DEG C. until the mixture is clear. It may then be dissolved in an organic solvent, or in an aqueous ammonia or amine solution. Alternatively the adduct I may be dissolved in the aqueous solution before the diol is added. In examples adducts of maleic anhydride with soybean oil or linseed oil or linseed-soya-dehydrated castor oil or dehydrated castor-safflower oil are heated at c. 95 DEG C. with ethylene glycol or diethylene or dipropylene glycol or polyethylene glycol or butane-1,4-diol with and without a 2:6-dimethylol-4-t-alkylphenol and the mixtures are dissolved in an aqueous solution of ammonia and diethanolamine or triethylene tetramine and optionally diethylene glycol monobutyl ether or ethoxyethyl acetate, to give aqueous stoving lacquers of particular use as primers.ALSO:Aqueous stoving lacquers comprise a mixture or partial esterification product of (I) an adduct of 1 p.b.w. maleic anhydride and 1.5-2.5 p.b.w. (up to 3.0 p.b.w. when an amine is present) of an unsaturated oil fatty acid, or hydroxyl-free polyol ester thereof, containing only isolated double bonds or one pair of conjugated double bonds, and (II) a diol, in approximately equivalent amounts; from 3-7 wt. % of the adduct of a primary or secondary amine may replace part of the diol. (see Division C3). In Examples such products (I) are mixed with diols (II) and diethanolamine or triethylene tetramine in aqueous ammonia solution optionally also containing diethylene glycol monobutyl ether or ethoxyethyl acetate and a pigment. The lacquers are used to coat steel panels; they may be applied by dipping or spraying. |
