Voided polyester film

• US 20040178139A1
• Filed: 04/11/2003
• Published: 09/16/2004
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Toray Advanced Materials Korea, Inc.
• Original Assignee: Toray Advanced Materials Korea, Inc.
• Inventors: Suh, Chang-Ho, Kim, Sang-Pil, Suh, Ki-Bong
• Granted Patent: US 6,984,322 B2
• Time in Patent Office: Days
• US Class Current: 210/488
• CPC Class Codes: B29C 55/005 characterised by the choice of materials
• CPC Class Codes: B29C 55/023 using multilayered plates or sheets
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29K 2105/16 Fillers
• CPC Class Codes: B32B 2250/03 3 layers
• CPC Class Codes: B32B 2250/244 All polymers belonging to those covered by group B32B27/36
• CPC Class Codes: B32B 2305/026 Porous
• CPC Class Codes: B32B 2307/4026 within the layer by addition of a colorant, e.g. pigments, dyes
• CPC Class Codes: B32B 2307/406 Bright, glossy, shiny surface
• CPC Class Codes: B32B 2307/518 bi-axially
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: C08K 3/013 Fillers, pigments or reinforcing additives
• CPC Class Codes: C08L 23/00 Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 25/04 Homopolymers or copolymers of styrene
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 67/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C08L67/06 takes precedence
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249986 : Void-containing component contains also a solid fiber or solid particle
• CPC Class Codes: Y10T 428/249987 : With nonvoid component of specified composition
• CPC Class Codes: Y10T 428/24999 : Inorganic
• CPC Class Codes: Y10T 428/249991 : Synthetic resin or natural rubbers

Abstract

The present invention relates to a biaxially stretched, laminated, white microporous polyester film, which can be used in a wide range of industrial applications including printing, imaging, advertising and display. The film of the present invention comprises a porous polyester resin layer B containing a thermoplastic resin non-compatible with polyester; a polyester resin-based photic layer A formed on one surface of the resin layer B, the aphotic layer A having a 60-degree gloss of the surface thereof of more than 100%; and an aphotic layer C formed on the other surface of the resin layer B, the aphotic layer C having a 60-degree gloss of the surface thereof of less than 50%. The total density of the photic layer A and the aphotic layer C is 0.55-1.2 g/cm³. This film has excellent gloss and flexibility so that it is very suitable for use in printing and imaging.

Claims

1. A microporous polyester film, which comprises:

a porous polyester resin layer B containing a thermoplastic resin non-compatible with polyester;

a polyester resin-based photic layer A formed on one surface of the resin layer B, the aphotic layer A having a 60-degree gloss of the surface thereof of more than 100%; and

an aphotic layer C formed on the other surface of the resin layer B, the aphotic layer C having a 60-degree gloss of the surface thereof of less than 50%.

2. The microporous polyester film of claim 1, wherein the total density of the photic layer A and the aphotic layer C is 0.55-1.2 g/cm³.

3. The microporous polyester film of claim 1, wherein the polyester resin layer B contains 3-30% by weight of a polyolefin-or polystyrene-based, non-compatible thermoplastic resin with a melt index of 2-20 g/minute.

4. The microporous polyester film of claim 1, wherein the photic layer A contains 0.005-0.5% by weight of silica particles with an average particle size of 0.5-5 μ

m.

5. The microporous polyester film of claim 4, wherein the photic layer A has a thickness of 1-10 μ

m.

6. The microporous polyester film of claim 1, wherein the polyester resin layer B contains 5-30% by weight of inorganic particles with an average particle size of 0.1-10 μ

m.

7. The microporous polyester film of claim 1, wherein the polyester resin layer B contains 0.005-0.5% by weight of a fluorescent whitening agent.

8. The microporous polyester film of claim 6, wherein the inorganic particles are one or more selected from titanium dioxide, calcium carbonate, silica, kaolin, mica, and talc barium sulfate.

9. The microporous polyester film of claim 7, wherein the fluorescent whitening agent is a bisbenzoxazole-based whitening agent.

10. The microporous polyester film of claim 1, wherein the aphotic layer C contains 0.5-10% by weight of silica particles with an average particle size of 1-20 μ

m.

11. The microporous polyester film of claim 10, wherein the aphotic layer C has a thickness of 1-10 μ

m.