Cathodic electrodeposition paint
AssigneeNippon Paint Co., Ltd.
InventorsHirotaka Kanato, Makoto Ando, Yoshio Kojima, Mitsuo Yamada, Ryoichi Murakami
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Abstract
Cathodic electrodeposition paints of the type in which a cationically modified epoxy resin is crosslinked with a blocked polyisocyanate crosslinker are disclosed. The paint contains a cationically modified epoxy resin having at least one oxazolidone ring in the molecule and a Tg ranging between 0.degree. C. and 35.degree. C., and a blocked alicyclic polyisocyanate. The use of lead based anticorrosive pigments may be eliminated or substantially reduced. When the alicyclic polyisocyanate is a bicycloalkane polyisocyanate, the use of organic solvent may also be reduced.
Claims17
In a cathodic electrodeposition paint comprising a mixture of (a) a cationically modified epoxy resin and (b) a blocked polyisocyanate crosslinker dispersed in an aqueous medium containing a neutralizing agent, the improvement wherein said cationically modified epoxy resin has at least one oxazolidone ring in the molecule and a Tg ranging between 10.degree. C. and 35.degree. C., wherein said blocked polyisocyanate crosslinker is a bicycloalkane diisocyanate or isophorone diisocyanate or a dimer, trimer or polyhydric alcohol adduct thereof, reversibly blocked with a lactam or oxime blocking agent, and wherein the paint contains less than 800 ppm of lead ions.
In a cathodic electrodeposition paint comprising a cationically modified epoxy resin and a blocked polyisocyanate crosslinker, the improvement wherein said blocked polyisocyanate crosslinker is a bicycloalkane polyisocyanate blocked with a blocking agent, and where the content of an organic solvent in the paint after diluting to a concentration suitable for actual electrodepositon onto a substrate is less than 2% by weight of the paint.
Dependencies are inferred from the claim text.