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: A non-drip, preferably self-adhesive, silicone elastomer composition crosslinkable by polyaddition, such as those polyorganosilanes (POS) bearing C2?C6?Si-alkenyl units and ?Si—H units but excluding fluorinated POS. The composition includes at least a thixotropic additive containing at least a fluorinated resin, preferably based on polyfluoroethylene (PTFE). The composition may be prepared from a Si—Vi polydimethylsiloxane (PDMS) and a Si—H PDMS crosslinked by platinum catalysis. Polytetrafluorethylene, a filler, particularly one containing silicone, optionally a ternary adherence promoter such as vinyltrimethosilane/glycidoxypropyltrimethoxysilane/butyl orthotitanate, and other typical additives may be added to the composition. The composition (not excluding the fluorinated POS as a possible constituent in the composition) may be used to produce joints in situ and/or as an adhesive, particularly in upholstery.

Abstract: The invention relates to a method for producing a sealed impregnation and/or release coating of flat joints, in particular of cylinder-head gaskets such as composite seals, metallic joints and multi-layered steel joints. The invention uses a silicone composition including at least a polyorganosiloxane A crosslinkable by a cationic and/or radical process by appropriate crosslinking functional groups, for example, of the alkenyl ether, acrylic, acrylate, epoxide and/or oxethane type; at least an initiator salt B selected among onium borates or an organometallic complex; and at least a reactive diluent C including a nonorganosilicon or organosilicon compound comprising in its structure at least a crosslinking functional group and optionally a secondary functional group different from the crosslinking functional group but capable of chemically reacting with a crosslinking functional group, for example of the hydroxyl, alkoxy and/or carboxyl type.

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.

Abstract: This photopolymerizable composition includes an grafted reactive telomer containing trifluoroethyl methacrylate units, a reactive diluent and a photopolymerization initiator. It gives hydrophobic transparent coatings.