Preparation of a multilayer coating

US5266361A · kind A · utility

Assignee

• BASK Lacke + Farben Aktiengesellschaft DE/DE · DE

Inventors

• Stephan Schwarte · Münster, DE
• Ulrich Poth · Munster, DE

Key dates

• Filing date: May 3, 1991
• Grant date: Nov 30, 1993
• Expiry date: May 3, 2011

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09D151/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention relates to a process for the preparation of a multicoat coating which uses an aqueous, clear topcoat composition containing a polyacrylate resin as binder. The polyacrylate resin can be obtained by adding an ethylenically unsaturated monomer (a1) which contains carboxyl groups, and a mixture (b) consisting of (meth)acrylic esters which are free from carboxyl groups and of ethylenically unsaturated monomers which contain hydroxyl groups, to an organic solvent or mixture of solvents either successively or alternately in part amounts and polymerizing the mixture in the presence of a radical-forming initiator, neutralizing the resultant polyacrylate resin after termination of the polymerization and dispersing it in water. The type and amount of (a1) and (b) are chosen such that the polyacrylate resin has a hydroxyl value of 40 to 200, an acid value of 20 to 100 and a glass transition temperature (T.sub.G) of -40.degree. C. to 60.degree. C.