Modified copolyesters and improved multilayer reflective films

• US 8,168,302 B2
• Filed: 11/10/2008
• Issued: 05/01/2012
• Est. Priority Date: 01/13/1998
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hebrink, Timothy J., Merrill, William W., Stover, Carl A.
• Primary Examiner(s): Chen, Vivian
• Application Number:
  US12/267,947
• Publication Number:
  US 20090062504A1
• Time in Patent Office: 1,268 Days
• Field of Search: None
• US Class Current: 428/480
• 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. An oriented polymeric film, comprising:

at least one film layer, the film layer comprising a copolyester having an intrinsic viscosity of about 0.4 dL/g to 0.7 dL/g wherein the copolyester comprises glycol subunits and carboxylate subunits,

the glycol subunits derived from 70 to 99 mol % C2-C4 diols and about 1 to 30 mol % comonomer glycol subunits derived from 1,6-hexanediol, and

the carboxylate subunits being 5 to 99 mol % naphthalate subunits, 1 to 95 mol % terephthalate or isophthalate subunits or mixtures thereof, and 0 to 30 mol % of comonomer carboxylate subunits derived from phthalic acid, t-butyl-isophthalic acid, lower alkyl esters of these acids, or a combination thereof;

wherein at least 0.01 to 2.5 mol % of the combined carboxylate and glycol subunits of the copolyester are derived from compounds having three or more carboxylate, ester, or hydroxy functional groups and the film layer has an in-plane birefringence of about 0.04 or less at 632.8 nm.

2. The oriented polymeric film of claim 1 wherein the intrinsic viscosity is no greater than 0.65 dL/g.

3. The oriented polymeric film of claim 1 wherein the intrinsic viscosity is no greater than 0.60 dL/g.

4. The oriented polymeric film of claim 1 wherein the copolyester comprises up to 30 mol % of comonomer carboxylate subunits derived from phthalic acid, t-butyl-isophthalic acid, lower alkyl esters of these acids, or a combination thereof.

5. The oriented polymeric film of claim 1 wherein at least 0.1 to 2.5 mol % of the combined carboxylate and glycol subunits of the copolyester are derived from compounds having three or more carboxylate, ester, or hydroxy functional groups.

6. The oriented polymeric film of claim 1 wherein 20 to 80 mol % of the carboxylate subunits are naphthalate.

7. The oriented polymeric film of claim 1 wherein 50 to 70 mol % of the carboxylate subunits are naphthalate.

8. A polymer, comprising:

a copolyester having an intrinsic viscosity of about 0.4 dL/g or greater, wherein the copolyester comprises glycol subunits and carboxylate subunits,

the glycol subunits derived from 70 to 99 mol % C2-C4 diols and about 1 to 30 mol % comonomer glycol subunits derived from 1,6-hexanediol, and

the carboxylate subunits being 5 to 99 mol % naphthalate subunits, 1 to 95 mol % terephthalate or isophthalate subunits or mixtures thereof, and carboxylate subunits derived from phthalic acid, t-butyl-isophthalic acid, lower alkyl esters of these acids, or a combination thereof;

wherein at least 0.01 to 2.5 mol % of the combined carboxylate and glycol subunits of the copolyester are derived from compounds having three or more carboxylate, ester, or hydroxy functional groups and the polymer has an in-plane birefringence of about 0.04 or less at 632.8 nm when uniaxially oriented into a film or film layer.

9. The polymer of claim 8 wherein the copolyester comprises up to 30 mol % of comonomer carboxylate subunits derived from phthalic acid, t-butyl-isophthalic acid, lower alkyl esters of these acids, or a combination thereof.

10. The polymer of claim 8 wherein the intrinsic viscosity is no greater than 0.60 dL/g.

11. The polymer of claim 8 wherein at least 0.1 to 2.5 mol % of the combined carboxylate and glycol subunits of the copolyester are derived from compounds having three or more carboxylate, ester, or hydroxy functional groups.

12. The polymer of claim 8 wherein 20 to 80 mol % of the carboxylate subunits are naphthalate.

13. The polymer of claim 8 wherein 50 to 70 mol % of the carboxylate subunits are naphthalate.