Polymeric composition
The invention relates to a polymeric composition, comprising: at least one thermoplastic resin having a glass transition temperature of at least about 220° C.; inorganic particulates having an average particle size in the range up to about 100 nanometers dispersed in the thermoplastic resin, the inorganic particulates having an index of refraction in the range from about 1.4 to about 3; and an effective amount of at least one dispersant to disperse the inorganic particulates in the thermoplastic resin. The polymer composition may be a high temperature thermoplastic suitable for forming, such as by molding, optical articles such as lenses.
1. An optically clear polymer composition suitable for making a molded article, comprising:
at least one thermoplastic resin having a glass transition temperature of at least about 220° C.;
inorganic particulates having an average particle size in the range up to about 100 nanometers dispersed in the at least one thermoplastic resin, the inorganic particulates having an index of refraction in the range from about 1.4 to about 3, the inorganic particulates having a zeta potential that is at least about +30 mV or more negative than −30 mV, the inorganic particulates comprising aluminum oxide, cerium oxide, titanium dioxide, zirconium dioxide, or a mixture of two or more thereof; and
an effective amount of at least one dispersant to disperse the inorganic particulates in the at least one thermoplastic resin;
wherein the polymer composition is thermally stable at a temperature up to about 400° C. and is made by heating pellets of the at least one thermoplastic resin at a temperature of at least about 70° C. and coating the pellets with an additive composition comprising the inorganic particulates and the dispersant; and
wherein the molded article has a visible light transmission in the visible light range of 400 to 1000 nm of at least about 85% after surface reflective losses, and a yellowness index of less than about 3.
2. The composition of claim 1 wherein the composition further comprises at least one bluing agent, at least one ultraviolet light absorber, at least one antioxidant, or a mixture of two or more thereof.
3. The composition of claim 1 wherein the composition further comprises one or more heat stabilizers, antistatic agents, pigments, dyes, optical brighteners, flame retardants, or a mixture of two or more thereof.
4. The polymer composition of claim 1 wherein the composition further comprises at least one melt processable glass reinforcing resin.
5. The composition of claim 1 wherein the thermoplastic resin comprises polycarbonate, polysulfone, polyolefin, polystyrene, polyalkylene terephthate, or a mixture of two or more thereof.
6. The composition of claim 1 wherein the thermoplastic resin comprises polycarbonate.
7. The composition of claim 1 wherein the thermoplastic resin comprises at least one polycarbonate derived from para, para′ isopropylidene diphenol, at least one polycarbonate derived from 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, a mixture thereof, or a copolymer derived from para, para′ isopropylidene diphenol and 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
8. The composition of claim 1 wherein the inorganic particulates comprise aluminum oxide and have an average particle size in the range up to about 50 nanometers and an index of refraction in the range from about 1.4 to about 3.
9. The composition of claim 1 wherein the dispersant comprises one or more fatty acids, fatty esters, fatty amides, fatty alcohols, polyalkylene glycols, polyoxyalkylene glycols, titanates, zirconates, paraffins, fluorocarbons, silicone oils, surfactants, or a mixture of two or more thereof.
10. The composition of claim 1 wherein the dispersant comprises one or more saturated fatty esters, one or more unsaturated fatty esters, or a mixture thereof.
11. The composition of claim 1 wherein the dispersant comprises a mixture of one or more fatty esters, one or more fatty acids and one or more glycerides.
12. The composition of claim 1 wherein the dispersant comprises one or more fatty amides.
13. The composition of claim 2 wherein the bluing agent comprises at least one blue dye, at least one violet dye, or a mixture thereof.
14. The composition of claim 2 wherein the ultraviolet light absorber comprises tetralkyl-2,2′-(1,4-phenylenedimethylidyne)bis malonate.
15. The composition of claim 2 wherein the antioxidant comprises at least one hindered phenol, at least one phosphite, or a mixture thereof.
16. The composition of claim 2 , wherein the antioxidant comprises 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione, bis(2,4-dicumylphenyl)pentaerythrithol diphosphite, or a mixture thereof.
17. The polymer composition of claim 1 wherein the polymer composition has a Tg of at least about 220° C.
18. A molded article comprising the polymer composition of claim 1 .
19. The molded article of claim 18 , wherein the article comprises a lens.