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 counteranions 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.

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 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.

Abstract: The invention concerns a cross-linkable adhesive silicone composition, and the use of said composition for bonding various substrates, comprising: a polyorganosiloxane (POS) with Si-Vi(polydimethylsiloxane &agr;,&ohgr;-dj-Vi) units; a crosslinking POS with SiH units; a platinum catalyst; an adherence promoter comprising vinyltrimethoxysilane, 3-glycidoxy-propyltrimethoxysilane and buryl titanate; and optionally a filler and/or a cross linkage inhibitor and/or an unsaturated POS resin such as MMviDDviQ or MDviQ. The invention aims at providing a highly adhesive glue having, before setting, a low viscosity adapted for easy application on the substrates to be bonded. The invention achieves this by providing a cross-linkable adhesive silicone composition as defined above and characterised in that it has a peeling force Fp≧0.25 N/mm. a viscosity &eegr;≧50.103mPa's at 25°, a tear resistance Rd≧6/mm (ASTM-624A) and a Shore hardness A≧35.

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 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.

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 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 of 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.