Abstract:
The invention relates to a coating which can be applied to a substrate comprising at least a thermoplastic fluorinated synthetic material, the hardness of which decreases from a first surface designed for application to the substrate in the direction of a second remote surface. The hardness gradient can be achieved by addition of filling- or reinforcing materials or addition of at least one thermoplastic synthetic material. The invention also relates to a seal which consists of or is coated with the inventive coating.
Abstract:
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 photoinitiators 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 concerns 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.