Micro-coextruded film modified with piezoelectric layers

• US 7,602,108 B2
• Filed: 04/27/2006
• Issued: 10/13/2009
• Est. Priority Date: 05/26/2005
• Status: Expired due to Fees

• Current Assignee: Eastman Chemical Company
• Original Assignee: Eastman Chemical Company
• Inventors: Shelby, Marcus David
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US11/412,451
• Publication Number:
  US 20060267459A1
• Time in Patent Office: 1,265 Days
• Field of Search: 310/311, 310/322, 310/334, 310/328, 310/800
• US Class Current: 310/363
• CPC Class Codes: B32B 2250/05 5 or more layers
• CPC Class Codes: B32B 2250/24 All layers being polymeric
• CPC Class Codes: B32B 2250/42 Alternating layers, e.g. ABAB(C), AABBAABB(C)
• CPC Class Codes: B32B 2307/20 having particular electrical or magnetic properties, e.g. piezoelectric
• CPC Class Codes: B32B 2307/202 Conductive
• CPC Class Codes: B32B 2307/412 Transparent
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2307/546 Flexural strength; Flexion stiffness
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 2551/08 Mirrors
• CPC Class Codes: B32B 2553/00 Packaging equipment or accessories not otherwise provided for
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/304 comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/322 comprising halogenated polyolefins, e.g. PTFE
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: B32B 27/38 comprising epoxy resins
• CPC Class Codes: B32B 27/42 : comprising condensation resins of aldehydes, e.g. with phenols, ureas or melamines
• CPC Class Codes: B32B 7/025 : Electric or magnetic properties
• CPC Class Codes: G02B 5/0841 : comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/281 : designed for the infrared light
• CPC Class Codes: G02B 5/285 : comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: G02B 5/286 : having four or fewer layers, e.g. for achieving a colour effect
• CPC Class Codes: G02B 5/305 : including organic materials, e.g. polymeric layers
• CPC Class Codes: H10N 30/206 : using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/857 : Macromolecular compositions
• CPC Class Codes: Y10S 310/80 : Piezoelectric polymers, e.g. PVDF

Abstract

Disclosed are layered films having a combination of piezoelectric layers that change dimension with applied voltage and non-piezoelectric layers. The layered structures can form a wide range of electrically switchable optical films. These films have applications in displays, polarizers, optical compensators, aesthetic films, and “hot” and “cold” mirrors that selectively reflect only certain wavelengths. Also disclosed are monochromatic and multicolor displays using these films.

Claims

1. A multilayer film comprising 5 or more total layers and at least 3 piezoelectric layers in which said piezoelectric layers are each separated by one or more intervening substantially transparent polymer layers,

wherein said piezoelectric layers comprise a polymer selected from the group consisting of poly(vinylidene fluoride), poly(vinyl fluoride), aromatic polyamide, polysulfone, cyanoethyl cellulose, polyvinylidene chloride, polyparaxylene and copolymers thereof, and

wherein the film is a coextruded film.

2. The film according to claim 1, which comprises from 10 to 1000 total piezoelectric and intervening layers.

3. The film according to claim 1, wherein said piezoelectric layers comprise poly(vinylidene fluoride) or copolymers of poly(vinylidene fluoride) and trifluoroethylene.

4. The film according to claim 1, wherein each of said intervening layers are the same or different.

5. The film according to claim 4, wherein said one or more non-piezoelectric layers comprise a polymer selected from the group consisting of polyalkylene naphthalate, polyalkylene terephthalate, polycarbonate, polyarylate, polyamide, polyimide, polyamide-imide, polyether-amide, polyether-imide, polyaryl ether, polyarylether ketone, aliphatic polyketone, polyphenylene sulfide, polysulfone, polystyrene, polyacrylate, polymethacrylate, cellulose derivative, polyalkylene, ionomeric resin, elastomer, silicone resin, epoxy resin, and polyurethane.

6. The film according to claim 4, wherein said one or more non-piezoelectric layers comprise a polymer selected from the group consisting of polyethylene naphthalate, polyethylene terephthalate, poly(cyclohexylene dimethylene terepthalate), polymethyl methacrylate, polycarbonate, and copolymers thereof.

7. The film according to claim 1, wherein said intervening layers comprise a tie layer.

8. The film according to claim 7, wherein the tie layer comprises monomers selected from the group consisting of maleic anhydride, glycidyl methacrylate, epoxides and mixtures thereof.

9. The film according to claim 1, which further comprises electrodes on the surface thereof.

10. The film according to claim 1, wherein each layer has a thickness of 0.05 to 5 microns.

11. The film according to claim 1, which further comprises one or more polarizing layers.