Heat-curable coating compositions

US5276125A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Josef Pedain · Cologne, DE
• Wilhelm Thoma · Leverkusen, DE
• Walter Schroer · Leverkusen, DE
• Waldemar Kling · Kandern, DE
• Manfred Dietrich · Leverkusen, DE

Key dates

• Filing date: Nov 21, 1990
• Grant date: Jan 4, 1994
• Expiry date: Nov 21, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09D175/04
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to heat-curable coating compositions containing PA0 A) a prepolymer having an average of 2-4 ketoxime-blocked NCO groups, having an average moleculer weight of 500-15,000 and prepared from aliphatic, cycloaliphatic and aromatic polyisocyanates and one or more polyhydroxy components which contain 0 to 30% by weight of ethylene oxide units and PA0 B) a crosslinking agent of the formula ##STR1## wherein R and R.sup.1 represent H or C.sub.1 -C.sub.4 -alkyl, the ratio of equivalents of blocked NCO groups in A) to NH.sub.2 groups in B) being 1.35:1 to 0.95:1, characterized in that at least one of the polyhydroxy compounds used for the preparation of the prepolymer contains, in stable dispersion, a polyurethane, a polyurethane-urea and/or a polyurea, which is substantially free from NCO groups, hydroxyl groups and amino groups and which are synthesized from aromatic, aliphatic and/or cycloaliphatic diisocyanates and from diamines, hydrazine and/or diols, provided that at least one of these components carries a radical having hydrophilic characteristics. The present invention also relates to the use of these coating compositions in a process for the coating, p…