High refractive index and optically clear copoly (carbosilane and siloxane) elastomers
View Patent ↗High refractive index and optically clear copoly(carbosilane and siloxane) elastomers and ophthalmic lenses made therefrom are provided. The elastomers are comprised of copolymers having carbosilane repeat units and siloxane repeat units. The copolymers and ophthalmic lenses of the present invention have a high refractive index and excellent folding recoverability.
1. A copoly (carbosilane and siloxane) elastomer having optical clarity comprising:
a crosslinkable copolymer consisting of carbosilane repeat units and siloxane repeat units, the carbosilane repeat units each having a carbon chain with 2 to 12 carbon atoms and the siloxane repeat units each being independently selected from the group consisting of dimethylsiloxane and diphenylsiloxane; and
a crosslinking agent;
wherein the elastomer has a refractive index of at least 1.43.
2. The elastomer of claim 1 , wherein the copolymer has the structure:
wherein
A is an alkenyl;
R 1 , R 2 , R 3 , and R 4 are each a hydrocarbon group;
Ph is a phenyl;
n is an integer from 10 to 500;
m is an integer from 5 to 100;
o is an integer from 2 to 12; and
p is an integer from 2 to 50.
3. The elastomer of claim 1 further comprising a platinum catalyst.
4. The elastomer of claim 1 , wherein the crosslinking agent is a hydrodimethyl-terminated silicone.
5. The elastomer of claim 1 further comprising a filler that is hexamethyldisilazane-treated silica and silicone resin material.
6. The elastomer of claim 1 further comprising a UV absorbing compound selected from the group consisting of allyl or methallyl functionalized benzotriazoles or benzophenones.