POWDER LACQUER AND ITS USE FOR THE COATING OF THERMORESISTANT SUBSTRATES

摘要

1. A powder lacquer consisting essentially of a mixture of A) a powder-form polyisocyanate component which is solid below 40 degrees C and liquid above 150 degrees C, B) a powder-form organic polyhydroxyl component which is solid below 40 degrees C and liquid above 150 degrees C and, optionally, C) auxiliaries and additives known from powder lacquer technology, components A) and B) being present in quantities corresponding to an equivalent ratio of isocyanate groups to hydroxyl groups of from 0.6:1 to 1.2:1, characterized in that component A) is essentially a polyisocyanate or polyisocyanate mixture a) which does not contain any blocking agents for isocyanate groups, b) which has a content of free isocyanate groups (expressed as NCO) attached to tertiary aliphatic or cycloaliphatic carbon atoms of from 8 to 24% by weight for a (mean) NCO functionality of at least 2.1, c) which has a content of urethane groups (expressed as -NH-CO-O-) of from 3 to 30% by weight and d) which has a content of isocyanurate groups (expressed as C3 N3 O3 ) of from 0 to 30% by weight.