Cellulose ester optical films

Patent metadata

Field	Value
Publication number	US-10836835-B2
Application number	US-201916665290-A
Country	US
Kind code	B2
Filing date	Oct 28, 2019
Priority date	Apr 13, 2011
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

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. An optical compensation plate comprising at least one +C film and at least one −A film wherein:
a. said +C film comprises 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 an aryl-acyl degree of substitution (“DS aryl ”) in the range of 0.75 to 2.80,
wherein said regioselectively substituted cellulose ester has an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 0.75 to 2.05,
wherein said regioselectively substituted cellulose ester has a hydroxyl degree of substitution (“DS OH ”) in the range of from 0.10 to 0.30,
wherein the regioselectivity of said regioselectively substituted 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 0.30 to 1.10,
wherein said +C optical film has an out-of-plane retardation (“R th ”) in the range of from +50 to +800 nm as measured at a spectral range from 370 to 1000 nm,
wherein said +C optical film has an in-plane retardation (“R e ”) in the range of from −15 to +15 nm as measured at a spectral range from 370 to 1000 nm,
wherein the DS aryl is greater than the DS alkyl ,
wherein said +C optical film has an average thickness in the range of from 40 to 120μm, and
b. said −A 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 ”) in the range of from 0.25 to 0.45, an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 1.85 to 2.35, an aryl-acyl degree of substitution (“DS aryl ”) in the range of from 0.35 to 0.65, and a Nz in the range of from 0.95 to about 1.5,
wherein the regioselectivity of said regioselectively substituted 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 −A optical film has an average thickness in the range of from 40 to 120 μm and in-plane retardation (“R e ”) as measured at a spectral range from 370 to 1000 nm in the range of from −100 to −300 nm, and
wherein said −A optical film has an out-of-plane retardation (“R th ”) in the range of from +50 to +150 nm as measured at a spectral range from 370 to 1000 nm.

2. The optical compensation plate of claim 1 wherein said +C film comprises a regioselectively substituted cellulose ester,
said regioselectively substituted cellulose ester has an aryl-acyl degree of substitution (“DS aryl ”) in the range of 1.00 to 1.60,
wherein said regioselectively substituted cellulose ester has an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 1.20 to 1.85,
wherein said regioselectively substituted cellulose ester has a hydroxyl degree of substitution (“DS OH ”) in the range of from 0.10 to 0.30,
wherein the regioselectivity of said regioselectively substituted 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 0.70 to 1.05,
wherein said +C optical film has an out-of-plane retardation (“R th ”) in the range of from +50 to +150 nm as measured at a spectral range from 370 to 1000 nm,
wherein said +C optical film has an in-plane retardation (“R e ”) in the range of from −5 to +5 nm as measured at a spectral range from 370 to 1000 nm,
wherein the DS aryl is greater than the DS alkyl ,
wherein said +C optical film has an average thickness in the range of from 40 to 120 μm.

3. The optical compensation plate of claim 1 wherein said regioselectively substituted cellulose ester comprises 50 to 90 weight % of said +C film.

4. The optical compensation plate of claim 1 wherein said regioselectively substituted cellulose ester comprises greater than 95 weight % of said +C film.

5. The optical compensation plate of claim 1 wherein
said −A film comprises 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 ”) in the range of from 0.31 to 0.43, an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 1.93 to 2.35, an aryl-acyl degree of substitution (“DS aryl ”) in the range of from 0.37 to 0.64, and a Nz in the range of from 0.97 to 1.44,
wherein the regioselectivity of said regioselectively substituted 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 in the range of from 0.23 to 0.38,
wherein said −A optical film has an average thickness in the range of from 40 to 120 μm and in-plane retardation (“R e ”) as measured at a spectral range from 370 to 1000 nm in the range of from −120 to −220 nm, and
wherein said −A optical film has an out-of-plane retardation (“R th ”) in the range of from +70 to +125 nm as measured at a spectral range from 370 to 1000 nm.

6. The optical compensation plate of claim 1 wherein
said −A film comprises 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 ”) in the range of from 0.31 to 0.43, an alkyl-acyl degree of substitution (“DS alkyl ”) in the range of from 1.95 to 2.35, an aryl-acyl degree of substitution (“DS aryl ”) in the range of from 0.37 to 0.60, and a Nz in the range of from 0.97 to 1.44,
wherein the regioselectivity of said regioselectively substituted 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 in the range of from 0.23 to 0.38,
wherein said −A optical film has an average thickness in the range of from 40 to 120 μm and in-plane retardation (“R e ”) as measured at a spectral range from 370 to 1000 nm in the range of from −150 to −200 nm, and
wherein said −A optical film has an out-of-plane retardation (“R th ”) in the range of from +75 to +100 nm as measured at a spectral range from 370 to 1000 nm.

7. The optical compensation pate of claim 1 wherein the aryl group of said aryl-acyl substituent of at least one +C film or at least one −A film comprises a substituted or unsubstituted phenyl group, wherein the alkyl group of said alkyl-acyl substituent of at least one +C film or at least one −A film comprises a C 1 to C 3 straight chain alkyl group.

8. The optical compensation plate of claim 7 wherein said aryl-acyl substituent comprises benzoate, wherein said alkyl-acyl substituent comprises acetate and/or propionate.

9. The optical compensation plate of claim 1 wherein said regioselectively substituted cellulose ester comprises 50 to 90 weight % of said −A film.

10. The optical compensation plate of claim 1 wherein said regioselectively substituted cellulose ester comprises greater than 95 weigh

Assignees

• Eastman Chem Co

Inventors

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

Classifications

• C08B3/16 Primary

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

• C08L1/14

  Mixed esters, e.g. cellulose acetate-butyrate · CPC title

• G02B1/04

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

• C08J5/18

  Manufacture of films or sheets · CPC title

• G02F1/133631

  with a spatial distribution of the retardation value · CPC title