Cellulose ester optical films

Patent metadata

Field	Value
Publication number	US-9975967-B2
Application number	US-201213409735-A
Country	US
Kind code	B2
Filing date	Mar 1, 2012
Priority date	Apr 13, 2011
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

Regioselectively substituted cellulose esters having a plurality of aryl-acyl substituents and a plurality of alkyl-acyl substituents are disclosed along with methods for making the same. Such cellulose esters may be suitable for use in optical films, such as optical films having certain Nz values, −A optical films, and/or +C optical films. Optical films prepared employing such cellulose esters have a variety of commercial applications, such as, for example, as compensation films in liquid crystal displays and/or waveplates in creating circular polarized light used in 3-D technology.

First claim

We claim:

1. A single layer optical film comprising a regioselectively substituted cellulose ester, wherein said regioselectively substituted cellulose ester comprises a plurality of alkyl-acyl substituents and a plurality of aryl-acyl substituents,
wherein said regioselectively substituted cellulose ester has a hydroxyl degree of substitution (“DS OH ”) of at least 0.30,
wherein said regioselectively substituted cellulose ester has an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 1.60 to 2.03,
wherein said regioselectively substituted cellulose ester has an aryl-acyl degree of substitution (“DS aryl ”) in the range of from 0.50 to 0.70,
wherein the regioselectivity of said cellulose ester is such that the sum of the aryl-acyl degrees of substitution at C2 and C3 (“C2DS aryl ” and “C3DS aryl ”) minus the aryl-acyl degree of substitution at C6 (“C6DS aryl ”) is greater than 0.20,
wherein said single layer optical film has an out-of-plane retardation (“R th ”) in the range of from 0 to +50 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, and
wherein said single layer optical film has an in-plane retardation (“R e ”) in the range of from −170 to −290 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, and
wherein said single layer optical film comprises a uniaxial stretched film; and wherein said single layer optical film has an Nz in the range of from 0.45 to 0.78.

2. The single layer optical film of claim 1 , wherein said DS OH is at least 0.40, wherein the sum of C2DS aryl and C3DS aryl minus C6DS aryl is in the range of from 0.22 to 0.50.

3. The single layer optical film of claim 1 , wherein said regioselectively substituted cellulose ester has a DS alkyl in the range of from 1.60 to 1.90, wherein said regioselectively substituted cellulose ester has a DS aryl in the range of from 0.60 to 0.70.

4. The single layer optical film of claim 1 , wherein said regioselectively substituted cellulose ester has a DS alkyl in the range of from 1.65 to 2.00, wherein said regioselectively substituted cellulose ester has a DS aryl in the range of from 0.50 to 0.68.

5. The single layer optical film of claim 1 , wherein said aryl-acyl substituent comprises a substituted or unsubstituted phenyl group, wherein said alkyl-acyl substituent comprises a C 1 to C 3 straight chain alkyl group.

6. The single layer optical film of claim 1 , wherein said aryl-acyl substituent comprises benzoate, wherein said alkyl-acyl substituent comprises acetate and/or propionate.

7. The single layer optical film of claim 1 , wherein said single layer optical film has an R th in the range of from 0 to +20 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, wherein said single layer optical film has an R e in the range of from −200 to −270 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, wherein said single layer optical film has an Nz of 0.50.

8. The single layer optical film of claim 1 , wherein said DS OH is at least 0.40, wherein the sum of C2DS aryl and C3DS aryl minus C6DS aryl is in the range of from 0.25 to 0.45.

9. The single layer optical film of claim 1 , wherein said single layer optical film comprises a thickness of 5 to 20 μm.

10. A liquid crystalline display (“LCD”) comprising said single layer optical film of claim 1 as a single layer compensation film, wherein said single layer optical film is a waveplate, wherein said LCD operates in in-plane-switching (“IPS”) mode.

11. The LCD of claim 10 , wherein said LCD further comprises a plurality of polarizing filters, wherein said LCD further comprises a liquid crystal layer disposed between two of said polarizing filters, wherein said single layer optical film is disposed between one of said polarizing filters and said liquid crystal layer.

12. An article of manufacture comprising said single layer optical film of claim 1 , wherein said single layer optical film is a quarter waveplate, wherein said article of manufacture is selected from the group consisting of 3-D glasses and a 3-D media display.

13. A single layer optical film comprising a regioselectively substituted cellulose ester, wherein said regioselectively substituted cellulose ester comprises an alkyl-acyl substituent and an aryl-acyl substituent,
wherein said regioselectively substituted cellulose ester has a hydroxyl degree of substitution (“DS OH ”) of 0.46 to 0.57,
wherein said regioselectively substituted cellulose ester has an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 1.81 to 2.03,
wherein said regioselectively substituted cellulose ester has an aryl-acyl degree of substitution (“DS aryl ”) in the range of from 0.51 to 0.62,
wherein the regioselectivity of said cellulose ester is such that the sum of the aryl-acyl degrees of substitution at C2 and C3 (“C2DS aryl ” and “C3DS aryl ”) minus the aryl-acyl degree of substitution at C6 (“C6DS aryl ”) is greater than 0.20,
wherein said aryl-acyl substituent comprises benzoate,
wherein said alkyl-acyl substituent comprises acetate and/or propionate,
wherein said single layer optical film has an out-of-plane retardation (“R th ”) in the range of from −50 to +50 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm,
wherein said single layer optical film has an in-plane retardation (“R e ”) in the range of from −100 to −300 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm,
wherein said single layer optical film has an Nz in the range of from 0.40 to 0.90, and
wherein said single layer optical film comprises a uniaxial stretched film.

14. The single layer optical film of claim 13 , wherein said single layer optical film has an R th in the range of from 0 to +50 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, wherein said single layer optical film has an R e in the range of from −170 to −290 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, wherein said single layer optical film has an Nz in the range of from 0.45 to 0.78.

15. The single layer optical film of claim 13 , wherein said single layer optical film has an R th in the range of from 0 to +20 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, wherein said single layer optical film has an R e in the range of from −200 to −270 nm as measured at a spectral range from 370 to 1000 nm and a normalized film thickness of 60 μm, wherein said single layer optical film has an Nz of 50.

16. The single layer optical film of claim 13 , wherein the sum of C2DS aryl and C3DS aryl minus C6DS aryl is in the range of from 0.25 to 0.45.

17. The single layer optical film of claim 13 , wherein said alkyl-acyl substituent comprises propionate.

18. The single layer optical film of claim 13 , wherein said alkyl-acyl substituent comprises acetate.

Assignees

• Buchanan Charles Michael
• Donelson Michael Eugene
• Guzman Morales Elizabeth
• Mackenzie Peter Borden
• Wang Bin
• Eastman Chem Co

Inventors

• Buchanan Charles Michael
• Donelson Michael Eugene
• Guzman-Morales Elizabeth
• Mackenzie Peter Borden
• Wang Bin

Classifications

• G02B1/04

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title

• C08J2301/14

  Mixed esters · CPC title

• C08B3/16 Primary

  Preparation of mixed organic cellulose esters {, e.g. cellulose aceto-formate or cellulose aceto-propionate} · CPC title

• G02F1/1335

  Structural association of cells with optical devices, e.g. polarisers or reflectors · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title