Microstructure-bearing articles of high refractive index
View Patent ↗Blends of oligomeric urethane multi(meth)acrylate; optionally at least one other monomer selected from the group consisting of acrylic monomers, styrenic monomers and ethylenically unsaturated nitrogen heterocycles, preferably a polyol multi(meth)acrylate; and nanoparticles of an ethylenically unsaturated, preferably (meth)acrylic-functionalized, titanium or zirconium compound can be cured by ultraviolet radiation in contact with a photoinitiator to produce optical resinous articles having high refractive indices, haze ratings of at most 5% and other properties which may be tailored according to the desired use.
1. An optical article having a surface with a replicated microstructure comprising a plurality of utilitarian discontinuities having an optical purpose,
said optical article comprising an organic resin having a haze rating corresponding to a value, as determined by ASTM procedure D1003 on a flat film 3.2 mm thick on a bisphenol A polycarbonate substrate, of up to 5% and said resin being prepared by curing a radiation curable composition comprising:
(A) at least one oligomeric urethane multi(meth)acrylate, optionally in combination with at least one other monomer effective to reduce viscosity, improve thermomechanical properties or increase refractive index;
(B) nanoparticles of at least one ethylenically unsaturated metal compound selected from the group consisting of tetravalent titanium and tetravalent zirconium compounds; and
(C) at least one photoinitiator.
2. The article according to claim 1 wherein component B is a titanium compound.
3. The article according to claim 2 wherein component B is a (meth)acryloxyalkyltrialkoxysilane-functionalized compound.
4. The article according to claim 3 wherein component B is 3-methacryloxypropyltrimethoxysilane-functionalized.
5. The optical article according to claim 4 wherein said curing is carried out using ultraviolet radiation.
6. The article according to claim 2 wherein component A is a reaction product of 2,2,4-trimethylhexane 1,6-diisocyanate, polycaprolactone diol and 2-hydroxyethyl methacrylate.
7. The optical article according to claim 6 wherein said curing is carried out using ultraviolet radiation.
8. The article according to claim 2 wherein said other monomer is also present.
9. The article according to claim 8 wherein the other monomer is an acrylic monomer, styrenic monomer or ethylenically unsaturated nitrogen heterocycle.
10. The article according to claim 8 wherein the other monomer is a polyol multi(meth)acrylate.
11. The article according to claim 10 wherein said polyol (meth)acrylate is hexanediol diacrylate.
12. The optical article according to claim 11 wherein said curing is carried out using ultraviolet radiation.
13. The article according to claim 2 having a molar ratio of titanium to urethane multi(meth)acrylate compound in the range of about 5-10:1.
14. The optical article according to claim 13 wherein said curing is carried out using ultraviolet radiation.
15. The optical article according to claim 2 wherein said curing is carried out using ultraviolet radiation.
16. The article according to claim 1 wherein component A comprises about 30-100% by weight of oligomeric urethane multi(meth)acrylate, with any balance being said other monomer.
17. The article according to claim 1 wherein component B comprises about 5-90% by weight of total components A and B.
18. The optical article according to claim 17 wherein said curing is carried out using ultraviolet radiation.
19. The optical article according to claim 1 wherein said curing is carried out using ultraviolet radiation.
20. The optical article according to claim 19 having an abrasion rating, as determined by ASTM procedure D968, no greater than 20.
21. The optical article according to claim 20 having an abrasion rating no greater than 10.
22. An optical article having a surface with a replicated microstructure comprising a plurality of utilitarian discontinuities having an optical purpose,
said optical article comprising an organic resin having a haze rating corresponding to a value, as determined by ASTM procedure D1003 on a flat film 3.2 mm thick on a bisphenol A polycarbonate substrate, of up to 5% and an abrasion rating, as determined by ASTM procedure D968, no greater than 20, and said resin being prepared by curing a radiation curable composition comprising:
(A) a reaction product of 2,2,4-trimethylhexane 1,6-diisocyanate, polycaprolactone diol and 2-hydroxyethyl methacrylate;
(B) nanoparticles of at least one 3-methacryloxypropyltrimethoxysilane-functionalized titanium compound; and
(C) at least one photoinitiator.
23. The optical article according to claim 22 wherein component A further comprises hexanediol diacrylate.
24. The optical article according to claim 23 wherein said curing is carried out using ultraviolet radiation.
25. The optical article according to claim 22 wherein said curing is carried out using ultraviolet radiation.