Process for preparing heat-curable, water-dilutable coating compositions for coating metal substrates

US4442244A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Gerhard Johannes · Taunusstein, DE
• Fali Shroff · Wiesbaden, DE
• Gerhard Dullis · Taunusstein, DE
• Dieter Steidl

Key dates

• Filing date: Jun 23, 1981
• Grant date: Apr 10, 1984
• Expiry date: Jun 23, 2001

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S524/904
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for preparing compositions for coating metal substrates or work pieces in an aqueous bath, in which the substrate forms the cathode. In this process 5-35% by weight of at least one epoxy resin, 2-20% by weight of at least one ketone and/or hydrocarbon resin, 15-60% by weight of at least one cationic synthetic resin having functional groups--this compound is a 10-50% by weight dispersion or solution--, 5-30% by weight of at least one organic cross-linking agent, which is solid at ambient temperature and 0-73% by weight of pigments and/or conventional adjuvants are processed together in one or more stages in a grinding apparatus to form a homogeneous coating composition. At least one stage being a wet operation. The composition has a particle size of less than 100 .mu.m, preferably less than 15 .mu.m. The grinding bath is adjusted with water to the solids content required for application. The particles obtained by the process are more homogeneous, with the result that, when applied to the object which is to be coated, a uniform layer thickness of the coating is obtained, which shows an increased impact strength.