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. A polymer composition for making a molded article, comprising:
at least one thermoplastic resin having a glass transition temperature of at least 220° C.;
inorganic particulates having an average particle size in the range up to 100 nanometers dispersed in the thermoplastic resin, the inorganic particulates having an index of refraction in the range from 1.4 to 1.8, the inorganic particulates being thermally stable at a temperature of at least 400° C., the dispersion of the inorganic particulates in the thermoplastic resin exhibiting a zeta potential of at least +30 mV or more negative than −30 mV; and
at least one dispersant to disperse the inorganic particulates in the thermoplastic resin, the dispersant being thermally stable up to a temperature of at least 350° C.;
wherein the polymer composition is thermally stable up to at least 400° C.; and
wherein the molded article exhibits a luminous light transmission of at least about 85% of the maximum theoretical value of the luminous transmission.
2. The composition of claim 1 wherein the composition further comprises one or more bluing agents, ultraviolet light absorbers, antioxidants, 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 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, or a mixture thereof; or a copolymer derived from para, para′ isopropylidene diphenol and 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
6. The composition of claim 1 wherein the inorganic particulates comprise aluminum oxide particulates.
7. The polymer composition of claim 1 wherein the polymer composition has a glass transition temperature of at least 220° C.
8. A molded article comprising the polymer composition of claim 1 .
9. The molded article of claim 8 , wherein the article comprises a lens.
10. The composition of claim 1 wherein the composition further comprises biphenol.
11. The composition of claim 10 wherein the biphenol is 4,4′ biphenol.
12. The composition of claim 1 wherein the molded article has a haze of less than about 3.
13. The composition of claim 1 wherein the molded article has a yellowness index of less than about 3.
14. The composition of claim 1 wherein the inorganic particulates are silane treated to enhance the dispersion of the inorganic particulates in the thermoplastic resin.
15. The composition of claim 1 wherein the inorganic particulates are surface treated with one or more titanates, one or more zirconates, or a mixture thereof.
16. The composition of claim 1 wherein the dispersant comprises one or more fatty acids, fatty esters, fatty amides, fatty alcohols, silicones, polyalkylene glycols, or a mixture of two or more thereof.
17. The composition of claim 1 wherein the dispersant comprises one or more titanates, one or more zirconates, or a mixture thereof.