Modified copolyesters and improved multilayer reflective films

• US 6,946,188 B2
• Filed: 10/01/2003
• Issued: 09/20/2005
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hebrink, Timothy J., Stover, Carl A., Merrill, William W.
• Primary Examiner(s): Chen, Vivian
• Application Number:
  US10/676,692
• Publication Number:
  US 20040086690A1
• Time in Patent Office: 720 Days
• Field of Search: 428/212, 428/480, 428/910, 528/302, 528/305, 528/307, 528/308, 528/308.6, 359/485, 359/487, 359/494, 359/500, 359/577, 359/586, 359/589
• US Class Current: 428/212
• CPC Class Codes: A61B 5/0803 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/22 Ergometry; Measuring muscular strength or the force of a muscular blow exercising apparatus A63B21/00 ; measuring of work or force in general G01L
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: B32B 2250/05 5 or more layers
• CPC Class Codes: B32B 2250/244 All polymers belonging to those covered by group B32B27/36
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/20 Inorganic coating
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2307/5825 Tear resistant
• CPC Class Codes: B32B 2307/584 Scratch resistance
• CPC Class Codes: B32B 2307/704 Crystalline
• CPC Class Codes: B32B 2457/202 LCD, i.e. liquid crystal displays
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 2551/08 Mirrors
• CPC Class Codes: B32B 27/08 : of synthetic resin
• CPC Class Codes: B32B 27/36 : comprising polyesters
• CPC Class Codes: B32B 7/023 : Optical properties
• CPC Class Codes: C08G 63/181 : Acids containing aromatic rings
• CPC Class Codes: C08G 63/199 : Acids or hydroxy compounds containing cycloaliphatic rings
• CPC Class Codes: C08G 63/20 : Polyesters having been prepared in the presence of compounds having one reactive group or more than two reactive groups
• CPC Class Codes: G02B 5/0841 : comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/0866 : incorporating one or more organic, e.g. polymeric layers
• CPC Class Codes: G02B 5/305 : including organic materials, e.g. polymeric layers
• CPC Class Codes: G02B 5/3083 : Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: Y10S 428/91 : Product with molecular orientation
• CPC Class Codes: Y10T 428/11 : Magnetic recording head
• CPC Class Codes: Y10T 428/24479 : including variation in thickness
• CPC Class Codes: Y10T 428/24612 : Composite web or sheet
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31786 : Of polyester [e.g., alkyd, etc.]

Abstract

A multilayered polymer film includes a first set of optical layers and a second set of optical layers. The first set of optical layers is made from a polyester which is often birefringent. The polyesters of the first set of optical layers typically have a composition in which 70-100 mol % of the carboxylate subunits are first carboxylate subunits and 0-30 mol % are comonomer carboxylate subunits and 70 to 100 mol % of the glycol subunits are first glycol subunits and 0 to 30 mol % of the glycol subunits are comonomer glycol subunits, where at least 0.5 mol % of the combined carboxylate and glycol subunits are comonomer carboxylate or comonomer glycol subunits. The multilayered polymer film may be used to form, for example, a reflective polarizer or a mirror.

Claims

1. A multilayered polymer film, comprising:

a plurality of first optical layers comprising a birefringent first copolyester; and

a plurality of second optical layers comprising a second copolyester having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the multilayered polymer film has been formed, wherein the second copolyester comprises carboxylate subunits derived from t-butyl-isophthalic acid or an ester thereof.

2. The multilayered polymer film of claim 1, wherein up to 30 mol % of the carboxylate subunits of the second copolyester are derived from t-butyl-isophthalic acid or an ester thereof.

3. The multilayered polymer film of claim 1, wherein the first copolyester comprises naphthalate subunits.

4. The multilayered polymer film of claim 1, wherein the second copolyester further comprises carboxylate subunits derived from cyclohexane dicarboxylic acid or an ester thereof.

5. The multilayered polymer film of claim 4, wherein the carboxylate subunits of the second copolyester are 5 to 95 mol % t-butyl-isophthalate and 5 to 95 mol % cyclohexane dicarboxylate.

6. The multilayered polymer film of claim 1, wherein the carboxylate subunits of the second copolyester further comprise naphthalate subunits.

7. The multilayered polymer film of claim 1, wherein the carboxylate subunits of the second copolyester further comprise terephthalate subunits.

8. The multilayered polymer film of claim 1, wherein the second copolyester further comprises glycol subunits derived from C2-C4 diols.

9. The multilayered polymer film of claim 8, wherein the second copolyester further comprises glycol subunits derived from 1,6-hexanediol or isomers thereof, trimethylol propane, or neopentyl glycol.

10. The multilayered polymer film of claim 1, wherein the second copolyester further comprises carboxylate subunits and 0.01 to 2.5 mol % of the combined carboxylate and glycol subunits of the second copolyester are derived from compounds having three or more carboxylate or ester functionalities, three or more hydroxy functionalities, or a combination thereof.

11. The multilayered polymer film of claim 1, wherein one in-plane index of refraction of the first copolyester is approximately equal to one in-plane index of refraction of the second copolyester after the multilayered polymer film has been formed.

12. The multilayered polymer film of claim 1, wherein the second copolyester further comprises glycol subunits derived from ethylene glycol, propylene glycol, or 1,4-butanediol.

13. The multilayered polymer film of claim 1, wherein the first and second copolyesters both comprise naphthalate subunits.

14. The multilayered polymer film of claim 1, wherein the second copolyester comprises glycol subunits selected from ethylene and butylene and comonomer glycol subunits derived from propylene glycol;

1,6-hexanediol;

neopentyl glycol;

polyethylene glycol;

diethylene glycol;

tricyclodecanediol;

1,4-cyclohexanedimethanol or isomers thereof;

norbornanediol;

bicyclo-octanediol;

trimethylol propane;

pentaerythritol;

1,4-benzenedimethanol or isomers thereof;

bisphenol A;

1,8-dihydroxy biphenyl and isomers thereof;

or 1,3-bis(2-hydroxyethoxy)benzene.

15. A multilayered polymer film, comprising:

a plurality of first optical layers comprising a birefringent first copolyester; and

a plurality of second optical layers comprising a second copolyester having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the multilayered polymer film has been formed, wherein the second copolyester comprises glycol subunits derived from trimethylol propane.

16. The multilayered polymer film of claim 15, wherein 0.01 to 5 mol % of the glycol subunits of the second copolyester are derived from trimethylol propane.

17. The multilayered polymer film of claim 16, wherein 0.1 to 2.5 mol % of the glycol subunits of the second copolyester are derived from trimethylol propane.

18. The multilayered polymer film of claim 15, wherein the first copolyester comprises naphthalate subunits.

19. The multilayered polymer film of claim 15, wherein the second copolyester comprises naphthalate subunits.

20. The multilayered polymer film of claim 19, wherein the second copolyester further comprises terephthalate subunits.

21. The multilayered polymer film of claim 15, wherein the second copolyester further comprises carboxylate subunits derived from cyclohexane dicarboxylic acid or an ester thereof.

22. The multilayered polymer film of claim 15, wherein the second copolyester further comprises glycol subunits derived from C2-C4 diols.

23. The multilayered polymer film of claim 22, wherein the second copolyester further comprises glycol subunits derived from 1,6-hexanediol or isomers thereof.

24. The multilayered polymer film of claim 15, wherein one in-plane index of refraction of the first copolyester is approximately equal to one in-plane index of refraction of the second copolyester after the multilayered polymer film has been formed.

25. The multilayered polymer film of claim 15, wherein the first and second copolyesters both comprise naphthalate subunits.