CLAIMS
1. A cross-linkable polymeric casting composition including an effective amount of
a divinyl ester monomer of a bicyclic or polycyclic compound; and optionally a minor amount of
a di- or polythio compound.
2. A cross-linkable polymeric casting composition according to claim 1 wherein the divinyl ester monomer is a divinyl ester of an alkoxylated bisphenol C or bisphenol S, or mixtures thereof.
3. A cross-linkable polymeric casting composition according to claim 1 wherein the divinyl ester monomer is selected from compounds having the formula I
wherein
G is selected from the group consisting of
M is selected from the group consisting of a bond,
methylene and — CH
2 — S — CH
2 — ·
R
1 t R , R
3 and R
4 which may be the same or different, are selected from the group consisting of hydrogen and alkyl of 1 to 6 carbon atoms,
n is an integer having a value of 0 to 10,
Y is hydrogen or a halogen; and
J is an unsaturated terminal group selected from allyl and the group of
formula
hydrogen or C
1 to C
6 ally!.
4. A cross-linkable polymeric casting composition according to claim 3 1100 wherein in said compounds of formula I the group G is naphthalene or provides a bisphenol S or bisphenol fluorene derivative and Y is selected from the group consisting of hydrogen, fluorine, chlorine and bromine.
5. A cross-linkable polymeric casting composition according to claim 1 wherein the divinyl ester monomer comprises one or more monomers selected 1155 from the group consisting of
an ethoxylated bisphenol S divinyl ester of the formula
»
a naphthalene-based ethoxylated divinyl ester of the formula
O 97/44372 ΙΌΤ/ΛΙ· J7/00310
28
(ID
a bisphenol fluorene diglycidyl atlylic monomer of the formula
and
a bisphenol S diallyl ether of the formula
6. A cross-linkable coating composition according to claim 1 wherein the divinyl ester monomer is present in amounts of from about 5 to about 80% by weight.
7. A cross-linkable casting composition according to claim 6 wherein the divinyl ester is present in an amount of about 10 to about 70% by weight,
8. A cross-linkable casting composition according to claim 1 wherein the dior polythiol compound is present and is selected from the group consisting of di-, tri- and tetra polythiol compounds.
9. A cros 'mkable casting composition according to claim 8 wherein the dior polythiol compound comprises one or more compounds selected from the group consisting of: Pentaerythritol Tetrakis (3-mercapto-propionate) [PTMP], Trimethylolpropane Tris (3-mercaptopropionate) [TTMP], 4-mercaptomethyl-3,6-dithia-1 ,8-octanedithiol [MDO], Pentaerythritol Tetrakis (3-mercaptoacetate)
[PTMA], Trimethylolpropane Tris (3-mercaptoacetate) [TTMA], 4-t-butyl-1 ,2-benzenedithiol, 2-mercaptoethylsulfide, 4,4'-thiodibenzenethiol
1 benzenedithiol, Glycol Dimercaptoacetate, Glycol Dimercaptopropionate Ethylene bld(3-Mercaptopropionate), Polyethylene Glycol Dimercaptoacetates, Polyethylene Glycol Di(3-Mercaptopiopionates), 2,5-bis(mercaptomethyl)-1,4-dithiane and 3,6-dithia-1 ,8-octamedithiol,
10. A cross-linkable coating composition according to claim 1 wherein the thiol compound is present in amounts of from about 5 to about 30% by weight of the total casting composition,
11. A cross-linkable casting composition according to claim 1 further comprising strain reducing agent.
12. A cross-linkable casting composition according to claim 11 wherein the strain reducing agent is present in an amount sufficient to decrease the cure time. 13. A cross-linkable casting composition according to claim 11 wherein the strain reducing agent comprises one or more compounds selected from the group consisting of: Epoxldised soybean oil, Propylene Oxide, Hexanediol diglycidyl ether (HDGE), 1,2 epoxy butane, Bisphenol fluorene diglycidyl ether (BPGE), Epolight 100MF, AG-601 and MY721.
14. A cross-linkable casting composition according to claim 11 wherein the secondary epoxldised monomer is present in amounts of from approximately 0.001% to 2.5% by weight based on the total weight of the casting composition. 15. A cross-linkable casting composition according to claim 1 further comprising one or more polymerisable comonomer selected from the group consisting of vinyls, al!ylics, polyoxyalky!ene glycol di-, tri-, tetra- and higher acrylates or methacrylates, polymerisable bisphenol monomers capable of forming a homopolymer having a high refractive index of more than 1.55, urethane monomers having 2 to 6 terminal acrylic or methacrylic groups, fluorene diacrylates or dimethacrylates, and thiodiacrylate or dimethacrylate monomers, 16. A cross-linkable casting composition according to claim 1 further comprising a polymerisation initiator selected from ultraviolet (U.V.) cationic or radical initiators.
17. A cross-linkable casting composition according to claim 16 wherein the
initiator comprises one or more compounds selected from the group consisting of: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2-methyl-1-[4-(methylthio) phenyl]-2-morpholinopropane«1-one), (hydruxycyclohexyl) phenyl ketone, (2-benzyl-2-N-dimethylamino-1«(4-morpholinophenyl)-1-butanone), (Benzyl Dimethyl Ketal), 2-(carbamoylazo)-substituted, 2-n-propoxy-9H-thioxanthen-9-one and Ethyl 4-(dimethylamino)benzoate.
18. An optical article prepared from the casting composition of claim 1.
19. An optical article according to claim 18 having a refractive index of at least approximately 1.55.
20. An optical article according to claim 18 having a refractive index of at least 1.57.
21. An optical article according to claim 18 having a density in the range of about 1.15 to 1.25g cm-3,