Painted sheet metal part with an anti-corrosion bonding layer based on polyacids and a method for applying such a bonding layer

US5830580A · kind A · utility

Assignee

• Mercedes-Benz Group AG · DE

Inventors

• Ute Flammer · Bad Marienberg, DE
• Fritz Mezger · Schenefeld, DE
• Anja Keller · Blaustein, DE
• Werner Funke · Havixbeck, DE

Key dates

• Filing date: Jul 3, 1996
• Grant date: Nov 3, 1998
• Expiry date: Jul 3, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31692
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to a painted sheet metal part, such as a car body, with a polyacid layer between the coat of paint and the surface of the sheet metal part and to a method for applying such a coating on the part before painting. Initially, the part is cleaned and de-greased, and subsequently the polyacid layer is deposited and stabilized. In order to be able to apply this layer without losing wet adhesion qualities of the coat of paint and the anti-corrosive effect of coating layer, while presenting fewer ecological disadvantages or harmful consequences, polyacids, which comprise homopolymers or copolymers of carboxylic acids containing double bonds or of functional esters of carboxylic esters, or copolymers of carboxylic acids with vinyl compounds, are used pursuant to the present invention as the protective bonding layer. The polyacids used are further combined with polymers having a glass transition temperature above 100.degree. C., such as phenolic resins, urea resins or epoxy resins, and/or with low molecular carboxylic acids with 2 to 30 carbon atoms in the carbon chain, in order to increase the corrosion protection effect. The deposited anti-corrosion layer is s…