HARD-COATED FILM, METHOD FOR PRODUCTION THEREOF AND ANTIREFLECTION FILM

• US 20100028600A1
• Filed: 08/31/2007
• Published: 02/04/2010
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Toray Industries Incorporated
• Original Assignee: Toray Industries Incorporated
• Inventors: Kojima, Satoshi, Abe, Yu, Mimura, Takashi
• Granted Patent: US 8,309,202 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: B29C 55/026 of preformed plates or sheets coated with a solution, a dispersion or a melt of thermoplastic material
• CPC Class Codes: B29C 55/085 in several stretching steps
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2995/0031 Refractive
• CPC Class Codes: C08J 2367/00 Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
• CPC Class Codes: C08J 7/043 Improving the adhesiveness of the coatings per se, e.g. forming primers adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50
• CPC Class Codes: C08J 7/044 Forming conductive coatings; Forming coatings having anti-static properties
• CPC Class Codes: C08J 7/046 Forming abrasion-resistant coatings; Forming surface-hardening coatings
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/111 using layers comprising organic materials
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24364 with transparent or protective coating
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/31 Surface property or characteristic of web, sheet or block

Abstract

There is provided a hard-coated film that includes a thermoplastic film and a hard coat layer placed thereon, has high surface hardness, is prevented from forming interference iris patterns, does not reduce image sharpness when used for antireflection films, and is prevented from causing screen glittering, external light reflection, or coloration irregularity of reflected light. The hard-coated film includes a polyester film and a hard coat layer placed on at least one side of the polyester film, wherein the hard coat layer has a surface with irregularities, an interface between the polyester film and the hard coat layer has irregularities, and the surface of the hard coat layer has 3D surface roughness parameters including an arithmetical mean deviation of surface Sa of from 15 nm to less than 150 nm and a kurtosis of surface height distribution Sku of from 1.5 to 5.

Claims

1. A hard-coated film, comprising:

a polyester film; and

a hard coat layer placed on at least one side of the polyester film, wherein

the hard coat layer has a surface with irregularities,

an interface between the polyester film and the hard coat layer has irregularities, and

the surface of the hard coat layer has 3D surface roughness parameters comprising an arithmetical mean deviation of surface Sa of from 15 nm to less than 150 nm and a kurtosis of surface height distribution Sku of from 1.5 to 5.

2. The hard-coated film of claim 1, wherein the interface between the polyester film and the hard coat layer has irregularities on the polyester film side, and projections of the irregularities on the polyester film side coincide with depressions of the hard coat surface profile in a thickness direction.

3. The hard-coated film of claim 1, wherein the hard coat layer is a thermally hardened layer.

4. The hard-coated film of claim 1, wherein the polyester film contains ultraviolet ray-absorbing agents.

5. The hard-coated film of claim 1, wherein the irregularities of the hard coat layer are formed without the aid of particles in the hard coat layer and the polyester film.

6. The hard-coated film of claim 1, wherein the interface between the polyester film and the hard coat layer has irregularities on the polyester film side, projections of the irregularities on the polyester film side coincide with projections of the hard coat surface profile in the thickness direction, and the hard-coated film has a heat shrinkage ratio of at most 0.8% at 150°

C. for 30 minutes in at least one direction.

7. The hard-coated film of claim 1, wherein the hard coat layer surface has an average Δ

a of from 0.2 degrees to 1.0 degree, wherein the average Δ

a is calculated from the formula Δ

a=(Δ

a1+Δ

a2)/2, wherein Δ

a1 and Δ

a2 are arithmetical mean slope angles of the hard coat layer surface in two directions perpendicular to each other, respectively.

8. The hard-coated film of claim 1, wherein the hard coat layer surface has an Sa2/Sa1 ratio of from 2 to 20, wherein Sa1 is the arithmetical mean deviation of surface (Sa) of the hard coat layer surface, and Sa2 is the arithmetical mean deviation of surface (Sa) of the interface between the polyester film and the hard coat layer, concerning the 3D surface roughness parameters.

9. The hard-coated film of claim 1, wherein Sku of the hard coat layer is from 1.5 to 3.

10. The hard-coated film of claim 1, wherein the hard-coated film has a haze of less than 3%.

11. An antireflection film, comprising:

the hard-coated film of claim 1; and

a low-refractive-index layer with a refractive index of at most 1.45 that is formed on the hard coat layer of the hard-coated film, optionally with a high-refractive-index layer with a refractive index of at least 1.55 interposed between the hard coat layer and the low-refractive-index layer.

12. The antireflection film of claim 11, wherein it has a haze of less than 4% and a transmittance of at most 5% at a wavelength of 380 nm.

13. A method for producing a hard-coated film, including the steps of:

applying a hard coating composition to a polyester film after longitudinal stretching during a polyester film forming process;

then slightly stretching the film 1.1 to 1.8 times in a transverse direction, while continuously feeding the film to a tenter;

then further stretching the film 2.5 to 3.5 times; and

then relaxing the film by 3% to 7% in a transverse direction, while the hard coat layer is thermally hardened.

14. The method of claim 13, further including the step of relaxing the film by 1.5% to 15% in a longitudinal direction and/or a transverse direction at 200°

C. to 240°

C. after the relaxation by 3% to 7%.