Stoving lacquer based on an epoxy resin containing an alkylidene polyphenol having an acid-functional group

摘要

Stoving enamel (I), contains (A) epoxy resins and (B) carboxy-functional alkylidene-polyphenols in amts. such that the COOH gps. are present in at least equimol. amts. w.r.t. the epoxide gps. in (A). Also claimed are (i) prepn. of (I) by mixing (A), (B) and opt. conventional additives and then adding an acid catalyst; and (ii) stoved packaging varnish film obtd. from (I), which is largely free from epoxide gp.- contg. components able to migrate from the coating. Pref. component (B) comprises reaction prods. of alkylidene-polyphenols with (a) halogenated carboxylic acids, (b) unsatd. dicarboxylic acids and/or anhydrides, or (c) resin acids and unsatd. di-acids and/or anhydrides. (I) may also contain hexamethylenetetramine, melamine resin and/or A-stage phenolic resin as crosslinker.