| 摘要 |
<p>Polymeric materials which are optically clear and resistant to discoloration are disclosed. In one embodiment, such compositions comprise optically clear, cross-linked polymers derived from a mixture comprising (A) a vinyl-containing polyorganosiloxane component, and (B) an organosilicon component including silicon-bonded hydride groups which react with vinyl groups included in (A) during the polymerization and (C) an effective platinum group metal-containing catalyst component, provided that the mole ratio of vinyl groups to silicon-bonded hydride groups in the mixture is greater than 1.2, preferably greater than about 4 or about 5, and is such that the polymer has a reduced discoloration susceptibility relative to a substantially identical polymer having a mole ratio of vinyl groups to silicon-bonded hydride groups in the precursor mixture equal to 1.2.</p> |
