Aqueous cathodic electrocoating material and a process for coating an electrically conductive substrate

US4781808A · kind A · utility

Assignee

• Basf Lacke & Farben Aktiengesellschaft · DE

Inventors

• Michael Geist · Munster, DE
• Georg Schon · Everswinkel, DE
• Arnold Dobbelstein · Cologne, DE
• Guther Ott · Munster, DE

Key dates

• Filing date: Apr 30, 1986
• Grant date: Nov 1, 1988
• Expiry date: Apr 30, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G18/8061
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention relates to an aqueous cathodic electrocoating material which contains a synthetic resin binder containing amino and/or hydroxyl groups and capable of being rendered water-soluble by the addition of an acid. The synthetic resin binder contains a mixture of crosslinking agents, as well as pigments, fillers, corrosion inhibitors, surface coating assistants, if appropriate catalysts, and organic solvents in an amount of up to 15% by weight, based on the total weight of the coating material. The mixture of crosslinking agents consists of at least two crosslinking agents which possess different reactivities and are based on activated esters and/or polyisocyanates blocked with different blocking agents. Different reactivities means that the crosslinking reactions begin at temperatures which are at least 10.degree. C. apart. The crosslinking reagent which reacts first is present in an amount of from 15 to 60 mol %, based on the mixture of crosslinking agents.