Described herein is an aqueous cathodically depositable electrodeposition coating material composition including at least one cathodically depositable polymer (a) and at least one carbon black pigment (b), where the at least one carbon black pigment (b) is a lamp black pigment having a number-based median primary particle size (d.sub.N,50%) of at least 50 nm and at most 200 nm. Also described herein is a method for at least partially coating an electrically conductive substrate by cathodic electrodeposition coating including immersing the substrate at least partially into an electrodeposition coating bath, which includes the electrodeposition coating material composition. Also described herein is an electrically conductive substrate, which is at least partially coated with a baked electrodeposition coating material composition and/or which is obtainable by the method. Further, described herein is a method of using the carbon black pigment (b) for improving corrosion protection and/or homogeneity of the film build.

An object of the present invention is to provide a preparation method for improving the edge part rust prevention property in the preparation of a cationic electrodeposition coating composition containing a bismuth compound as a curing catalyst. The present invention provides a method for preparing a cationic electrodeposition coating composition, including a step of preparing a resin emulsion (i) containing an aminated resin (A) and a blocked isocyanate curing agent (B), a step of preparing a pigment dispersion paste (ii) containing a bismuth-metal oxide mixture liquid (C) containing a bismuth compound (c1), a metal oxide (c2), a monohydroxycarboxylic acid (c3) having 3 to 5 carbon atoms in total and a solvent; a pigment dispersion resin (D); a polyvalent acid (E); and a pigment (F), and a step of mixing the resin emulsion (i) and the pigment dispersion paste (ii).

Disclosed herein is an aqueous electrocoating material including at least one specific binder and at least one bismuth compound, a method of using the aqueous electrocoating material for at least partially electrocoating a substrate, a coated substrate obtained from said method and an article or component including said substrate.

Described herein is an aqueous coating composition (A) for at least partly coating an electrically conductive substrate with an electrocoat material, including (A1) at least one cathodically depositable resin binder, (A2) at least one crosslinking agent, (A3) at least 100 ppm of bismuth, based on the total weight of the coating composition (A), and (A4) lithium, in a form dissolved in (A), the lithium not exceeding a fraction of 300 ppm, based on the total weight of the coating composition (A). Also described herein are a method for producing (A), a coating method, and an at least partly coated substrate obtainable by the method.

The present invention provides a cationic electrodeposition coating composition with a rust prevention property enhanced by improving the adhesion and the blocking property of a coating film obtained from a cationic electrodeposition coating composition as compared with conventional ones. The present invention provides a cationic electrodeposition coating composition including an aminated epoxy resin and a blocked polyisocyanate curing agent, wherein the aminated epoxy resin is an aminated epoxy resin obtained by reacting an amine compound with an epoxy resin, the aminated epoxy resin has a molecular weight distribution of 2.7 or less, and a rate of elongation of an electrodeposition coating film formed by applying the cationic electrodeposition coating composition to a steel sheet such that a cured film thickness is 20 m, followed by baking at 160 C. for 15 minutes, is 0.1 to 4.5%.