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 μm, followed by baking at 160° C. for 15 minutes, is 0.1 to 4.5%.

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).

Cathodically depositable electrocoat materials comprising basic bismuth nitrate, further comprising at least one binder having reactive functional groups and at least one crosslinker containing the complementary reactive functional groups which are able to enter into thermal crosslinking reactions.

Aqueous cathodic electrocoat compositions with improved edge protection and methods for preparing such electrocoat compositions are described herein. In an exemplary embodiment, an electrocoat composition includes water; a crosslinkable resin comprising a binder of an epoxy-amine adduct and a crosslinking agent; a neutralizing agent for neutralizing the epoxy amine adduct, wherein the neutralizing agent has a pKa value of greater than 0; and a pigment paste. The pigment paste may comprise silica, barium sulfate or silica and barium sulfate.

The present invention provides a cationic electrodeposition coating composition that has both good anti-cissing property and good coating film appearance. This is a cationic electrodeposition coating composition containing a silicone compound (A) having an SP value of more than 10.5 and 15.0 or less, and a film forming resin (B), wherein the silicone compound (A) is contained in an amount of 0.01 parts by mass or more and 4.5 parts by mass or less per 100 parts by mass of the resin solid content of the film forming resin (B). For example, the silicone compound (A) is at least one species selected from the group consisting of a polyether modified silicone compound (A-1), a polyester modified silicone compound (A-2), and a polyacrylic modified silicone compound (A-3).

A coating method for a cationic electrodeposition coating material includes: a step of immersing a metallic article to be coated in a first solution bath, a step of immersing the article in a second solution bath and a step of immersing the article in a third solution bath; and at least one of the three steps includes a cationic electrodeposition coating in which a current is applied. A coating film formed through the three steps contains at least: a base resin component (A), a reaction component (B) and a catalyst (C). The first solution bath, the second solution bath and the third solution bath contain the base resin component (A), the reaction component (B) and the catalyst (C) in a combination of one or two of the components.

An epoxy resin emulsion includes a continuous phase including an aqueous carrier and an acid. The emulsion also includes a dispersed phase including an epoxy resin. The epoxy resin is the reaction product of an amine compound and a first epoxy reactant. The first epoxy reactant itself includes the reaction product of (1) an aromatic diol monomer, (2) a di-glycidyl ether of Bisphenol A and/or a di-glycidyl ether of catechol, and (3) a C8-C18 alkyl phenolic end-capping agent. The (1) aromatic diol monomer has the structure:

##STR00001##

In this structure, each of R.sup.1-R.sup.4 is independently a hydrogen atom, a C.sub.1-C.sub.8 alkyl group, a C.sub.3-C.sub.8 cycloalkyl group, an aryl group, an aralkyl group, a halide group, a cyano group, a nitro group, a blocked isocyanate group, or a C.sub.1-C.sub.8 alkyloxy group or wherein any two or more of R.sup.1-R.sup.4 may be a fused ring.

The present disclosure relates to a cathodically depositable aqueous electrodeposition coating material including at least one epoxide-amine adduct (a), at least one pigment and/or at least one filler (b), and at least one crosslinking agent (c), a fraction of at least 25 wt % of the crosslinking agent (c), based on the total weight of the crosslinking agent (c), being formed by at least one tris(alkoxycarbonylamino)-1,3,5-triazine; to a method for coating an electrically conductive substrate by cathodic electrodeposition coating using said electrodeposition coating material; to a substrate coated accordingly; and also to a use of a tris(alkoxycarbonylamino)-1,3,5-triazine in a cathodically depositable electrodeposition coating material for reducing or eliminating the sensitivity to disruption of the electrodeposition coating bath toward impurities present therein through phosphates and/or through other metal salts which have been carried into the electrodeposition coating bath as a result of pretreatment steps ahead of the electrodeposition coating.

The invention provides a method of improving the corrosion resistance of a metal substrate. The method comprises: (a) electrophoretically depositing on the substrate a curable electrodepositable coating composition to form a coating over at least a portion of the substrate, and (b) heating the substrate to a temperature and for a time sufficient to cure the coating on the substrate. The electrodepositable coating composition comprises a resinous phase dispersed in an aqueous medium, the resinous phase comprising: (1) an ungelled active hydrogen-containing, cationic salt group-containing resin electrodepositable on a cathode; (2) an at least partially blocked polyisocyanate curing agent; and (3) a pigment component comprising an inorganic, platelike pigment having an average equivalent spherical diameter of at least 0.2 microns. The electrodepositable coating composition demonstrates a pigment-to-binder ratio of at least 0.5. The coating composition contains less than 8 percent by weight of a grind vehicle.

A cationic electrodeposition paint composition comprising a cationic base-containing resin (A), a blocked polyisocyanate compound (B), and a modified imidazole (C) having a specific structure, wherein the cationic base-containing resin (A) is a cationic base-containing epoxy resin and/or a cationic base-containing acrylic resin.