use of under the influence of uv light and boratonium - photoinitiatoren with cationic curable silikonzusammensetzungen for the manufacture of flachdichtungen, especially zylinderkopfdichtungen

摘要

The invention concerns the use of cross-linkable silicone compositions for fast, economical and simple impregnation and/or varnishing of flat joints (e.g. cylinder head gaskets). More precisely it concerns the use of silicone compositions cross-linkable under UV radiation, by cationic process and in the presence of specific phoinitiators selected among onium borates or organometallic complexes, of which the borate counter-anions contain at least a boron bound to at least a substituted phenyl (Me, F). The silicone liquid precursor is a polydimethylsiloxane (PDMS) substituted by cross-linking functional groups, by cationic process (Gfp) under UV of the epoxy or vinyloxy type. These Gfp are present at the rate of 0.15 to 2.0 pr kg of PDMS. The invention also relates to the method for impregnating/varnishing flat joints (e.g. cylinder head gaskets) using the specific PDMS composition+photoinitiator of borate type as well as the treated joints and the composition themselves.