Hydrosilylation-Curable Silicone Rubber Composition for Optical Applications

The patent changes the chemical composition parameters by using specific rare-earth metal salts (cerium, lanthanum, neodymium, praseodymium, or samarium) with controlled amounts (5-300 ppm relative to component A) instead of conventional metal oxide powders. This parameter change allows achieving heat resistance while maintaining transparency, as these rare-earth salts provide thermal stability without the opacity issues of traditional metal oxide fillers.

The patent creates a composite silicone rubber composition by combining organopolysiloxane (A), silicone resin (B), organohydrogenpolysiloxane (C), rare-earth metal salt (D), and hydrosilylation catalyst (E). This composite approach allows synergistic effects where the rare-earth metal salt provides heat resistance while the hydrosilylation-curable system maintains transparency and mechanical properties, resolving the contradiction between heat resistance and transparency.

The patent modifies the compositional parameters by incorporating rare-earth metal salts at specific concentrations (5-300 ppm) and controlling the ratios of polysiloxane (A), silicone resin (B), and organohydrogenpolysiloxane (C). These parameter changes enable simultaneous achievement of transparency (90% or more total light transmittance), appropriate hardness, and heat resistance, while maintaining compatibility with existing hydrosilylation curing processes.

The patent develops a multi-component composite system that integrates rare-earth metal salts into the hydrosilylation-curable silicone rubber matrix. This composite structure provides synergistic properties: the organopolysiloxane and silicone resin provide base properties and transparency, the rare-earth metal salt provides heat resistance, and the organohydrogenpolysiloxane enables crosslinking for hardness control, achieving a balanced performance profile.