Optical waveguide, method of manufacturing thereof, and polymeric composition

Patent metadata

Field	Value
Publication number	US-9784905-B2
Application number	US-201314424161-A
Country	US
Kind code	B2
Filing date	Jun 27, 2013
Priority date	Jun 29, 2012
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

An optical waveguide includes a textured light-diffracting layer. The optical waveguide is made from a poly(aliphatic ester)-polycarbonate copolymer having very high flow properties and good impact properties. A method of manufacturing the waveguide by injection molding, a method of incorporating a microprism structure and a method of scattering light by directing light through a light-scattering layer thereby produced on the waveguide are also disclosed.

First claim

The invention claimed is:

1. An optical waveguide, comprising:
a poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight of from about 15,000 to about 25,000 and a melt flow rate measured according to ASTM D1238 (300° C., 1.2 kgf) of at least 100 g/10 min, wherein the optical waveguide has a wall thickness of less than 0.5 mm, and wherein the optical waveguide includes a textured light-diffracting layer having a thickness of less than 10 microns.

2. The optical waveguide of claim 1 , wherein the poly(aliphatic ester)-polycarbonate copolymer contains about 6.0 mol % of aliphatic ester units derived from sebacic acid.

3. The optical waveguide of claim 1 , wherein the poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 16,000 to about 18,000.

4. The optical waveguide of claim 1 , wherein the poly(aliphatic ester)-polycarbonate copolymer has a glass transition temperature of greater than 130° C. or between 110° C. and 145° C.

5. The optical waveguide of claim 1 , wherein the optical waveguide has a notched Izod impact strength of at least 550 J/m when measured according to ASTM D256 at 23° C.

6. The optical waveguide of claim 1 , wherein the optical waveguide has a ductility of 100% when measured according to ASTM D256 at 23° C.

7. The optical waveguide of claim 1 , wherein the optical waveguide has an impact energy at peak of at least 50 J, when measured according to ASTM D3763 at 23° C.

8. The optical waveguide of claim 1 , wherein the optical waveguide has a wall thickness of less than 0.3 mm.

9. The optical waveguide of claim 1 , wherein the optical waveguide has at least 85% light transmission when measured according to ASTM D1003 at 3.2 mm thickness.

10. The optical waveguide of claim 1 , wherein the optical waveguide has less than 1% haze when measured according to ASTM D1003 at 3.2 mm thickness.

11. The optical waveguide of claim 1 , wherein the poly(aliphatic ester)-polycarbonate copolymer contains about 6 mol % of aliphatic ester units derived from sebacic acid and contains polycarbonate units derived from bisphenol-A.

12. The optical waveguide of claim 1 , wherein the optical waveguide has a melt flow rate measured according to ASTM D1238 (300° C., 1.2 kgf) of at least 100 g/10 min; a notched Izod impact strength of at least 550 J/m when measured according to ASTM D256 at 23° C.; and at least 85% light transmission when measured according to ASTM D1003 at 3.2 mm thickness.

13. The optical waveguide of claim 1 , wherein the optical waveguide has a notched Izod impact strength of at least 570 Jim when measured according to ASTM D256 at 23° C.; at least 85% light transmission when measured according to ASTM D1003 at 3.2 mm thickness; and an impact energy at peak of at least 50 J, when measured according to ASTM D3763 at 23° C.

14. The optical waveguide of claim 1 , wherein the optical waveguide has a glass transition temperature of greater than 130° C. and a weight average molecular weight of from about 16,000 to about 18,000.

15. A device comprising the optical waveguide of claim 1 .

16. The device of claim 15 , wherein the device is a liquid crystal display, a television, or a computer monitor screen.

17. The optical waveguide of claim 1 wherein the poly(aliphatic ester)-polycarbonate copolymer has a notched Izod impact strength of at least 570 Jim when measured according to ASTM D256 at 23° C.; and an impact energy at peak of at least 50 J, when measured according to ASTM D3763 at 23° C.;
wherein a surface of the optical waveguide includes a textured light-diffracting layer having a thickness of less than 10 microns.

18. A method of making an optical waveguide, comprising:
injecting a poly(aliphatic ester)-polycarbonate copolymer into an injection mold, wherein the poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 15,000 to about 25,000 and a melt flow rate measured according to ASTM D1238 (300° C., 1.2 kgf) of at least 100 g/10 min, and wherein the injection mold includes a textured surface on an interior surface; and
curing the copolymer in the injection mold to form an optical waveguide with a textured light-diffracting layer derived from the textured surface; and
removing the optical waveguide from the injection mold, wherein the optical waveguide has a wall thickness of less than 0.5 mm, and wherein the optical waveguide includes a textured light-diffracting layer having a thickness of less than 10 microns.

19. The method of claim 18 , wherein the copolymer in the optical waveguide has a weight average molecular weight of about 17,000 during the injection.

20. The method of claim 18 , wherein the weight average molecular weight of the copolymer in the optical waveguide is controlled by chain-chopping prior to injection into the injecting mold.

21. The method of claim 20 , wherein the chain-chopping is performed by treating the copolymer with a redistribution catalyst.

22. The method of claim 21 , wherein the redistribution catalyst is a tetraalkylphosphonium hydroxide, tetraalkylphosphonium alkoxide, tetraalkylphosphonium aryloxide, a tetraalkylphosphonium carbonate, a tetraalkylammonium hydroxide, a tetraalkylammonium carbonate, a tetraalkylammonium phosphite, a tetraalkylammonium acetate, or a combination thereof, wherein each alkyl independently contains 1 to 6 carbon atoms.

23. The method of claim 22 , wherein the redistribution catalyst is tetra-n-butylphosphonium hydroxide.

24. The method of claim 21 , wherein the redistribution catalyst is used in the amount of 400 ppm by weight or less based on the weight of the poly(aliphatic ester)-polycarbonate copolymer.

25. The optical waveguide of claim 1 , the optical waveguide being made of a tabular molding and having a light-scattering layer formed directly on the face or back.

26. The optical waveguide of claim 25 , wherein the aliphatic ester units in the copolymer are derived from a polymethylene-dicarboxylic acid, and the ratio of the polymethylene-dicarboxylic acid falls between 1 and 30 mol % of the monomer that constitutes the polycarbonate units.

27. The optical waveguide of claim 25 , wherein the light-scattering layer has a microprism structure.

28. A method for producing the optical waveguide of claim 25 , in which, when a tabular molding for it is injection-molded, a microprism structure that serves as a light-scattering layer is transferred onto its face or back with a stamper.

29. The optical waveguide of claim 25 , wherein the microprism structure is a regular tetrahedral structure.

30. The optical waveguide of claim 29 , wherein the regular tetrahedral structure has a height falling between 10 and 300 μm.

31. The optical waveguide of claim 1 , further comprising a hydrolytic stabilizer.

32. The optical waveguide claim 1 , wherein the optical waveguide does not contain an acrylic resin.

33. A device, comprising: the optical waveguide of claim 25 and a light source.

34. A method of scattering light, which comprises: illuminating a surface of the optical waveguide of claim 25 with a light and directing the light through the light-scattering layer.

35. The optical waveguide of claim 1 further comprising a polycarbonate th

Assignees

• Sabic Innovative Plastics Ip Bv
• Sabic Global Technologies Bv

Inventors

• Malinoski Jon Michael

Classifications

• B29D11/00663

  Production of light guides · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• B29K2069/00

  Use of PC, i.e. polycarbonates {or derivatives thereof}, as moulding material · CPC title

• G02B6/0036

  2-D arrangement of prisms, protrusions, indentations or roughened surfaces · CPC title

• G02B6/0065 Primary

  Manufacturing aspects; Material aspects · CPC title