Easy-to-clean, mechanically stable coating composition for metallic surfaces and process for coating a substrate using said composition

摘要

The present invention is directed to an optically clear coating made from a composition comprising an epoxy-melamine resin. The coating is obtained on a metallic substrate and has a very rigid structure and a unique combination of properties that includes hydrophobicity/easy-to-clean, adhesion to bright chrome, abrasion resistance and chemical resistance. The coating composition comprises (A) a mixture of at least one hydrolysable silane and one hydrolysable metal compound, the compounds of said mixture being partly or fully hydrolyzed and partly or fully condensed, (B) at least one melamine derivative selected from derivatives having formula (C₃N₃)(NR⁴R⁵)₃, and derivatives having formula (C₃N₃)(NR⁴R⁵)_3-p(NR⁴R⁶)_p, wherein R⁴ and R⁵ are independently selected from H, hydroxymethylene and alkoxymethylene, with the proviso that at least one of the R⁴ groups is a hydroxymethylene or alkoxymethylene group, and R⁶ is —CH₂—NR⁴(C₃N₃)(NR⁴R⁵)₂ or —CH₂—O—CH_2-NR⁴(C₃N₃)(NR⁴R⁵)₂, and p is 1 or 2, and either at least one partially or fully fluorinated, at least partly hydrolyzed and condensed silane compound, this compound being part of the said mixture (A) of hydrolysable silanes, or (C) at least one partially or fully fluorinated organic compound containing at least one group which may bind to hydroxy groups.