Electrodeposition of epoxy compositions
AssigneePPG Industries, Inc.
InventorsJoseph F. Bosso, Marco Wismer
Life of this patent
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Abstract
Synthetic resins which are water-dispersible epoxy resins having epoxy groups, chemically-bound quaternary ammonium base salts, can be dissolved or dispersed in water to provide aqueous coating compositions. Such compositions, in which these resins are the major resinous component, can be applied by electrodeposition and deposit on the cathode to provide coatings of improved properties, including a high degree of resistance to corrosion or staining.
Claims19
A method of coating a conductive substrate serving as a cathode which comprises passing electric current between an anode and said cathode in electrical contact with a water-dispersed composition comprising an aqueous dispersion comprising an ungelled, water-dispersible epoxy resin having in the resin molecule:
- a. at least one 1,2-epoxy group,
- b. at least about 0.05 percent by weight of chemically-bound nitrogen, at least one percent of which is in the form of a quaternary ammonium base salt of an acid having a dissociation constant greater than about 1 .times. 10.sup.-.sup.5,
- c. said water-dispersed composition containing boron in the form of boric acid, an ester of boric acid or a compound which can be cleaved to form boric acid in aqueous medium.
Dependencies are inferred from the claim text.