Optical material with improved colour
Disclosed are polymerizable compositions for ophthalmic lenses. The compositions employ peroxide-based polymerization initiators with decreased capacity for dye degradation. The compositions enable the inclusion of color-balancing dyes, resulting in lenses with improved clarity and color balance.
1. A polymerizable composition comprising:
a) at least one allyl monomer or oligomer;
b) at least one catalyst suitable for initiating the polymerization of said allyl monomer or oligomer;
c) at least one UV absorber; and
d) at least one dye;
wherein the at least one catalyst has the following formula:
R 1 —O—O—C(═O)—O—R 2 or R 1 —O—O—C(═O)—R 2
wherein R 1 is an alkyl chain having from 1 to 12 carbon atoms and R 2 is a multivalent polyether bound to a plurality of alkylperoxy carbonate groups; or wherein R 2 is an alkyl chain having from 1 to 12 carbon atoms and R 1 is a multivalent polyether bound to a plurality of alkylperoxy carbonate groups.
2. The polymerizable composition of claim 1 , wherein the allyl monomer or oligomer is ethylene glycol bis(allyl carbonate) or diethylene glycol bis(allyl carbonate), or an oligomer thereof, or a mixture thereof.
3. The polymerizable composition of claim 1 , wherein the at least one allyl monomer or oligomer is present in an amount ranging from 20 to 99.5% by weight, based on a total weight of the composition.
4. The polymerizable composition of claim 1 , wherein the catalyst R 1 and R 2 groups are saturated.
5. The polymerizable composition of claim 1 , wherein the catalyst alkyl chain comprises 3 to 8 carbon atoms.
6. The polymerizable composition of claim 1 , wherein the UV absorber is a benzophenone having the following structure:
wherein R 3 and R 4 are each independently H or an alkyl chain having from 1 to 12 carbon atoms.
7. The polymerizable composition of claim 6 , wherein R 3 and R 4 are methyl.
8. The polymerizable composition of claim 6 , wherein R 3 and R 4 are H.
9. The polymerizable composition of claim 1 , wherein R 1 or R 2 is bound to 2, 3 or 4 alkylperoxy carbonate groups.
10. A process for the manufacture of an ophthalmic lens, comprising polymerizing the polymerizable composition of claim 1 to form an ophthalmic lens.
11. An ophthalmic lens obtained by polymerizing a polymerizable composition comprising:
a) at least one allyl monomer or oligomer;
b) at least one catalyst suitable for initiating the polymerization of said allyl monomer or oligomer;
c) at least one UV absorber; and
d) at least one dye;
wherein the at least one catalyst has the following formula:
R 1 —O—O—C(═O)—O—R 2 of R 1 —O—O—C(═)—R 2
wherein R 1 is an alkyl chain having from 1 to 12 carbon atoms and R 2 is a multivalent polyether bound to a plurality of alkylperoxy carbonate groups; or wherein R 2 is an alkyl chain having from 1 to 12 carbon atoms and R 1 is a multivalent polyether bound to a plurality of alkylperoxy carbonate groups.
12. The ophthalmic lens of claim 11 , wherein the lens has a yellow index of less than 5.
13. The ophthalmic lens of claim 11 , wherein the lens has a haze value of less than 0.5%.
14. The ophthalmic lens of claim 11 , wherein the lens has a light-cut value of less than 410 nm.
15. The ophthalmic lens of claim 11 , wherein R 1 or R 2 is bound to 2, 3 or 4 alkylperoxy carbonate groups.
16. The polymerizable composition of claim 1 , wherein said polyether has from 5 to 30 carbon atoms.
17. The polymerizable composition of claim 1 , wherein the at least one allyl monomer or oligomer is present in an amount ranging from 50 to 99.5% by weight, based on a total weight of the composition.
18. The polymerizable composition of claim 1 , wherein the at least one allyl monomer or oligomer is present in an amount ranging from 80 to 99.5% by weight, based on a total weight of the composition.