Process for coating electrically conductive substrates, water-based coatings and crosslinking agents containing masked NCO groups

US5324402A · kind A · utility

Assignee

• Basf Lacke & Farben Aktiengesellschaft · DE

Inventors

• Gunther Ott · Hachenburg, DE
• Ulrich Heimann · Munster, DE
• Walter Jouck · Munster, DE
• Udo Reiter · Telgte, DE
• David J. Santure · Novi, US

Key dates

• Filing date: Feb 4, 1993
• Grant date: Jun 28, 1994
• Expiry date: Feb 4, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G18/8009
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention relates to a cathodic electro-dipping process wherein the electro-dipping primer employed contains a crosslinking agent which can be obtained by PA0 (I) reacting, in a first stage, PA1 (a) diphenylmethane diisocyanate and PA1 (b) a monoalcohol or a mixture of monoalcohols to give an intermediate product (A) containing isocyanate groups, and PA0 (II) reacting this intermediate product (A) in a second stage with PA1 (c) a polyol or a mixture of polyols to give an intermediate product (B) containing hydroxyl groups which PA0 (III) is reacted in a third stage either with PA1 (d) a cycloaliphatic, aliphatic or araliphatic polyisocyanate or a mixture of such polyisocyanates and PA1 (e) a monofunctional masking agent or a mixture of such masking agents or with PA1 (f) a partially-masked polyisocyanate prepared from (d) and (e) to give a crosslinking agent which is free from isocyanate groups.