Abstract: Aqueous cathodic electrodeposition lacquer coating compositions are provided which comprise (A) certain water soluble synthetic resin binders containing amino groups; (B) crosslinking reagents which react with resin (A), and (C) certain soluble or insoluble transesterification catalysts for the crosslinking reagents. Methods of forming baked finish coatings which are cathodically deposited on electrically conductive surfaces using the lacquer coatings are also disclosed.

Abstract: The invention relates to a cathodically depositable aqueous electro-dip lacquer coating composition containing as synthetic resin binder(A) from 50 to 99% by weight, based on the total quantity of synthetic resin binder, of one or more amino-1,2-epoxy resins, the amino-1,2-epoxy resin or--where several amino-1,2-epoxy resins are present--the mixture of amino-1,2-epoxy resins(a) having an average molecular weight (Mn) of from 700 to 10,000,(b) containing per 1000 molecular weight units from 0.2 to 3.6 lateral or terminal ethylenic double bonds corresponding to a hydrogenation iodine number of from 5 to 90,(c) containing primary and/or secondary alcoholic hydroxyl groups corresponding to a hydroxyl number of from 30 to 450 and(d) having an amine number of from 30 to 150,(B) from 1 to 50% by weight of a substantially non-acid polyester of a polycarboxylic acid containing at least two terminal or lateral, saturated and/or unsaturated .beta.