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AssigneeBASF Lacke + Farben, AG
InventorsWolfgang Batzill, Horst Diefenbach, Michael Geist, Eberhard Schupp
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The invention relates to water-dispersible binders which are intended for cationic electropaints and are based on reaction products which are formed from modified epoxy resins and primary and/or secondary amines and which can, if desired, also contain crosslinking agents, pigments, flow-control agents and other customary auxiliaries. They contain as reaction products those which have been prepared by reacting (A) low molecular weight epoxy resins which contain epoxy compound aromatic groups and have an epoxide equivalent weight of less than 375 with (B) aliphatic and/or alicyclic polyfunctional alcohols having hydroxyl groups or carboxylic acids having carboxylic groups and both having a molecular weight of less than 350 and addition of the hydroxyl groups and carboxylic groups to the epoxy groups of (A) in such a way that the reaction products of (A) and (B) contain 10-45% of aromatic groups, calculated as the phenylene group, and have terminal epoxy groups. (C) reacting the terminal epoxy groups of the reaction products of (A) and (B), and thus chain-lengthening, with the phenolic hydroxyl groups of a mononuclear or polynuclear phenol which has at least two phenolic hydroxyl groups and at east one .alpha.,.beta.-olefinically unsaturated amidomethyl group of the following general formula ##STR1## as a substituent on the aromatic rings(s) and in which R.sup.1 and R.sup.2 are identical to or different from one another and represent hydrogen or a methyl group, and (D) reacting the intermediate procuct obtained from (A), (B) and (C) with a primary or secondary amine or an ammonium salt.
A water-dispersible binder for cationic electropaints based on reaction products which are formed from modified epoxy resins and primary amines, secondary amines, or mixtures thereof, comprising:
A process for preparing a binder for cationic electropaints based on reaction products formed from modified epoxy resins and amines comprising reacting:
A process for the electrophoretic coating of an electrically conductive substrate which is connected as the cathode, from an aqueous bath based on cationic binders at least partially neutralized with acids, wherein the binders have been prepared by reacting:
Dependencies are inferred from the claim text.