Brominated polycarbonate films
View Patent ↗Optical articles, including light management films, prepared from brominated polycarbonate material are disclosed. The brominated polycarbonate provides a film exhibiting good light transmittance, high refractive index, good flame resistance, and good mechanical properties.
1. An article, comprising:
an optical film having a microstructure on a surface thereof, wherein the optical film comprises a brominated polycarbonate comprising 1 to about 45 weight part bromine based on the total weight of the brominated polycarbonate.
2. The article of claim 1 , wherein the brominated polycarbonate has a refractive index greater tan or equal to about 1.585.
3. The article of claim 1 , wherein the brominated polycarbonate has a refractive index greater than or equal to about 1.595.
4. The article of claim 1 , where the brominated polycarbonate is derived from Bisphenol A and tetrabromobisphenol A.
5. The article of claim 1 , wherein the brominated polycarbonate comprises a blend of a non-brominated polycarbonate and a polycarbonate comprising brominated units.
6. The article of claim 1 , wherein the brominated polycarbonate comprises a blend of a non-brominated polycarbonate and a brominated carbonate oligomer.
7. The article of claim 6 , wherein the blend comprises about 30 to about 60 weight percent brominated carbonate oligomer based on the total weight of the blend.
8. The article of claim 1 , wherein the brominated polycarbonate comprises a blend of brominated carbonate oligomer and a polycarbonate comprising brominated units.
9. The article of claim 8 , wherein the polycarbonate comprising brominated units is derived from Bisphenol A and tetramobisphenol A.
10. The article of claim 1 , wherein the optical film exhibits a VTM-2 flammability rating according to UL 94 Edition 5 of Oct. 29, 1996.
11. The article of claim 1 , wherein the optical film exhibits a VTM-1 flammability rating according to UL 94 Edition 5 of Oct. 29. 1996.
12. The article of claim 1 , wherein the article is a brightness enhancing film, a light management film, a Fresnel lens element, a diffraction grating, a video disc, a reflector, an ophthalmic lens, a projection display, a traffic signal, or an illuminated sign.
13. A method of preparing an article, comprising:
molding a brominated polycarbonate to form an optical film having a microstructure on a surface thereof,
wherein the brominated polycarbonate comprises 1 to about 45 weight percent bromine based on the total weight of the brominated polycarbonate.
14. The method of claim 13 , wherein the molding comprises calendaring, molding, embossing, hot stamping, or a combination comprising at least one of the foregoing.