MULTILAYER OPTICAL FILM, METHOD OF MAKING THE SAME, AND TRANSACTION CARD HAVING THE SAME

• US 20070298271A1
• Filed: 06/15/2007
• Published: 12/27/2007
• Est. Priority Date: 06/23/2006
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: North, Diane, Johnson, Stephen, Hebrink, Timothy, Liu, Richard
• Application Number:
  US11/763,622
• Publication Number:
  US 20070298271A1
• Time in Patent Office: Days
• US Class Current: 428/480
• CPC Class Codes: B29C 35/02 Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mouldcold vulcanisation B29C35/18 ; vulcanising tyres, presses therefor B29D30/0601
• CPC Class Codes: B29C 48/0018 combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/185 comprising six or more components, i.e. each component being counted once for each time it is present, e.g. in a layer
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 55/005 characterised by the choice of materials
• CPC Class Codes: B29C 55/12 biaxial
• CPC Class Codes: B29D 11/00788 Producing optical films
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/30 comprising vinyl (co)polymers; comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/23 Identity cards
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/351 Translucent or partly translucent parts, e.g. windows
• CPC Class Codes: B42D 25/36 comprising special materials
• CPC Class Codes: B42D 25/425 by deformation, e.g. embossing
• CPC Class Codes: B42D 25/445 : using chemical means, e.g. etching
• CPC Class Codes: B42D 25/455 : using heat
• CPC Class Codes: G02B 1/04 : made of organic materials, e.g. plastics G02B1/08 takes precedence
• CPC Class Codes: G02B 1/10 : Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 5/0268 : characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0284 : used in reflection
• CPC Class Codes: G02B 5/0841 : comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/3016 : involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02B 5/3041 : comprising multiple thin layers, e.g. multilayer stacks
• CPC Class Codes: Y10T 428/31786 : Of polyester [e.g., alkyd, etc.]

Abstract

A multilayer optical film includes alternating layers of first and second optical layers; the first optical layer comprising a first polyester, wherein the first polyester comprises first dicarboxylate monomers and first diol monomers, and from about 0.25 to less than 10 mol % of the first dicarboxylate monomers have pendant ionic groups; the second optical layer comprising a second polyester; and wherein the first and second optical layers have refractive indices along at least one axis that differ by at least 0.04. The multilayer optical film may be a polarizer film, a reflective polarizer film, a diffuse blend reflective polarizer film, a diffuser film, a brightness enhancing film, a turning film, a mirror film, or a combination thereof. The multilayer optical film may also be a transaction card such as a financial transaction card, an identification card, a key card, or a ticket card. A method of making the multilayer film is also disclosed.

Claims

1. A multilayer optical film comprising:

alternating layers of first and second optical layers;

the first optical layer comprising a first polyester, wherein the first polyester comprises first dicarboxylate monomers and first diol monomers, and from about 0.25 to less than 10 mol % of the first dicarboxylate monomers have pendant ionic groups;

the second optical layer comprising a second polyester; and

wherein the first and second optical layers have refractive indices along at least one axis that differ by at least 0.04.

2. The multilayer optical film of claim 1, wherein the pendant ionic group comprises a sulfonate, phosphonate, or carboxylate group, or a combination thereof.

3. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise sodium, potassium, lithium, zinc, magnesium, calcium, cobalt, iron, or antimony counterions, or a combination thereof.

4. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise a salt of 5-sulfoisophthalate.

5. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise sodium 5-sulfoisophthalate.

6. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise naphthalene dicarboxylate and a salt of 5-sulfoisophthalate;

and the first diol monomers comprise ethylene glycol.

7. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise naphthalate dicarboxylate, terephthalate, and a salt of 5-sulfoisophthalate;

and the first diol monomers comprise one or more monomers selected from the group consisting of ethylene glycol, 1,6-hexanediol, neopentylglycol, and trimethylol propane.

8. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise terephthalate and a salt of 5-sulfoisophthalate;

and the first diol monomers comprise ethylene glycol and neopentyl glycol.

9. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise terephthalate, cyclohexane dicarboxylate, and a salt of 5-sulfoisophthalate;

and the first diol monomers comprise ethylene glycol and cyclohexane dimethanol.

10. The multilayer optical film of claim 1, wherein the first dicarboxylate monomers comprise cyclohexane dicarboxylate and a salt of 5-sulfoisophthalate;

and the first diol monomers comprise ethylene glycol and cyclohexane dimethanol.

11. The multilayer optical film of claim 1, wherein the second polyester comprises second dicarboxylate monomers and second diol monomers, and from about 0.25 to less than 10 mol % of the second dicarboxylate monomers have pendant ionic groups.

12. The multilayer optical film of claim 1, the first optical layer comprising about 0.5 wt % or less of a monovalent organic salt.

13. The multilayer optical film of claim 11, the first and second optical layers each having a sodium ion concentration of at least about 1000 ppm.

14. The multilayer optical film of claim 1, the multilayer optical film having an average peel strength of at least about 0.34 N/mm as measured according to ISO/IEC 10373-1:

1998(E).

15. The multilayer optical film of claim 1, the multilayer optical film having a haze value of less than about 50%.

16. The multilayer optical film of claim 1, comprising a polarizer film, a reflective polarizer film, a diffuse blend reflective polarizer film, a diffuser film, a brightness enhancing film, a turning film, a mirror film, or a combination thereof.

17. A transaction card comprising:

first and second polymer layers each having a thickness of at least about 125 um; and

a multilayer optical film disposed between the first and second polymer layers, the multilayer optical film comprising;

alternating layers of first and second optical layers;

the first optical layer comprising a first polyester, wherein the first polyester comprises first dicarboxylate monomers and first diol monomers, and from about 0.25 to less than 10 mol % of the first dicarboxylate monomers have pendant ionic groups;

the second optical layer comprising a second polyester; and

wherein the first and second optical layers have refractive indices along at least one axis that differ by at least 0.04;

wherein the transaction card has an average transmission of at least 50% from 400 to 700 nm.

18. The transaction card of claim 17, having an average transmission of less than about 16% from 800 to 1000 nm.

19. The transaction card of claim 17, having a haze of less than about 12%.

20. The transaction card of claim 17, the first and second polymer layers independently comprising polyvinylchloride, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, styreneacrylonitrile, polymethylmethacrylate, glycol-modified polyethylene terephthalate, copolyester, or a combination thereof.

21. The transaction card of claim 17, comprising a financial transaction card, an identification card, a key card, or a ticket card.

22. A method of making a multilayer optical film, the method comprising:

coextruding alternating layers of first and second optical layers;

the first optical layer comprising a first polyester, wherein the first polyester comprises first dicarboxylate monomers and first diol monomers, and from about 0.25 to less than 10 mol % of the first dicarboxylate monomers have pendant ionic groups; and

the second optical layer comprising a second polyester;

preheating the coextruded alternating layers to a preheating temperature above the Tg of the first and second optical layers;

stretching the coextruded alternating layers after preheating, such that the first and second optical layers have refractive indices along at least one axis that differ by at least 0.04.

23. The method of claim 22, further comprising post-heating the coextruded alternating layers for at least 5 seconds after stretching, wherein post-heating comprises heating at a post-heating temperature of at least 204°

C.