Rhone-poulenc Industries

Rhone-poulenc Specialites Chimiques

Noel Bouverot

Paul Medard

Alain Viale

Robert Lagarde

Improved heat-curable organopolysiloxane compositions, easily vulcanizable into silicone elastomers, are comprised of (A) a major amount of a diorganopolysiloxane gum, (B) a reinforcing filler therefor, (C) optionally, a diorganopolysiloxane oil, (D) an organic peroxide catalyst, and minor amounts of at least three of the following four additives: (E) an organohydrogenopolysiloxane, (F) an organofluorinated polymer, (G) an organosilonxane irgabcompound bearing at least one acroyloxyalkyl or methacroyloxyalkyl substituent covalently bonded to a silicon atom thereof, and (H) a boron compound.

Heat-curable organopolysiloxane compositions

Pasty organopolysiloxane compositions are facilely injection-molded into elastomeric shaped articles at low pressures, at a temperature ranging from about 125.degree. C. to about 225.degree. C., and in a molding cycle of less than about 25 seconds, said pasty organopolysiloxane compositions comprising an intimate admixture of:

Injection-molding of pasty, thermosetting organopolysiloxane compositions

Pasty organopolysiloxane compositions having a penetration of from 80 to 400 and which can be thermoset into elastomers having good mechanical properties, are comprised of an intimate admixture of (i) 100 parts by weight of a diorganopolysiloxane oil having a viscosity of from 500 to 300,000 mPa.multidot.s at 25.degree. C., (ii) 7 to 85 parts by weight of reinforcing silicas having a specific surface area of at least 50 m.sup.2 /g, said reinforcing silicas comprising from 55 to 95% precipitated silica and 5 to 45% pyrogenic silica, (iii) 1 to 20 parts by weight of a structuring inhibitor, and (iv) 0.1 to 4 parts by weight of an organic peroxide cross-linking agent.

Growing community of inventors

Saint Symphorien D'Ozon, France

Noel Bouverot