Abstract: Disclosed are improved electrodeposition bath compositions comprising a resinous phase dispersed in an aqueous medium, the resinous phase being comprised of an active hydrogen containing ionic electrodepositable resin and a curing agent, where the improvement comprises the addition to a lead-free electrodeposition bath of at least one calcium compound in an amount of about 10 to 10,000 parts per million of total calcium and not more than about 200 parts per million soluble calcium, based on electrodeposition bath weight. The electrodeposition bath compositions are preferably cationic and provide for excellent corrosion resistance over a variety of metal substrates including untreated steel. Also disclosed is a method of electrocoating a conductive substrate using the improved electrodeposition bath compositions of the invention. Metallic substrates which are coated using the method of the invention are also disclosed.

Abstract: Disclosed are electrodepositable coating compositions containing novel polysiloxanes which are the reaction product of a polysiloxane containing silicon hydride and at least one material which contains one or more unsaturated bonds capable of undergoing hydrosilylation reaction. The electrodepositable coating compositions can be anionic or cationic electrodepositable coatings and are resistant to cratering. Also disclosed is a method of electrocoating a conductive substrate using the electrodepositable coating compositions of the invention. Novel low molecular weight polysiloxanes having pendant groups which contain unsaturated bonds capable of undergoing hydrosilylation reaction are also disclosed.

Abstract: Electrodepositable coating composition bath is prepared and maintained to reduce the growth of bacteria in and around the bath. The composition has dispersed in an aqueous medium a resinous phase, said composition having a pH of at least 5, said resinous phase having basic nitrogen groups which are at least partially neutralized with an acid of the formula: ##STR1## wherein R is hydrogen or an alkyl group with one to four carbon atoms. The amount of this acid to neutralize the cationic resinous phase can be an initial amount greater than 90 of the milliequivalents of sulfamic acid based on the total milliequivalents of neutralizing acid in the bath for the electrodeposition coating of articles in the bath. Also, the bath is maintained by post addition of sulfamic acid to a level of greater than 80 weight percent of the milliequivalents of neutralizing acid when the bath has less than or greater than 90 weight percent of the milliequivalents of neutralizing acid in the bath as sulfamic acid.

Abstract: An additive for cationic electrodepositable coating compositions is disclosed which improves hiding ability, stability, rheology and oil spot resistance. The additive is present in amounts of between 0.5 to 40 weight percent and is prepared by polymerizing in aqueous medium, under free radically initiated conditions, an aqueous dispersion of a polymerizable, ethylenically unsaturated monomer composition in the presence of a cationic polymeric surface active substance. The coating composition additionally has between 60 to 99.5 weight percent of a cationic salt group containing film forming polymer. Also disclosed is a method for coating which includes electrodepositing the above composition on an electrically conductive cathode.

Abstract: Disclosed is a method for providing a wood substrate with durability against weathering comprising at least two steps (A) and (B). Step (A) consists of appying to the wood substrate a transparent treatment comprising an organosilicon-containing compound having at least one hydrolyzable silyl group in a carrier for said compound. Step (B) consists of thereafter coating the wood substrate with a transparent, film-forming, coating composition. The coating composition is characterized in that a transparent free film from the coating composition retains an elongation of at least 20 percent after at least 1,000 hours exposure in a Xenon Weatherometer.

Abstract: Novel compositions of matter comprising a reaction product of a tannin and epoxy material are hereby provided. The novel reaction products can be dispersed in an aqueous or solvent medium for use as a treating or coating composition which imparts excellent corrosion resistance to metals and exhibits excellent substrate and intercoat adhesion.

Abstract: An electrophoretic process for preparing corrosion-resistant substrates is disclosed. The process comprises sequential electrophoretic steps of anodic electrophoresis, followed by cathodic electrophoresis. The electrophoretic composition comprising an aqueous dispersion of a reaction product of a tannin, an epoxy material and a cationic water-solubilizing salt group is employed.