HARD COAT FILM, POLARIZING PLATE, IMAGE DISPLAY DEVICE, AND METHOD FOR PRODUCING HARD COAT FILM

• US 20130029118A1
• Filed: 04/13/2011
• Published: 01/31/2013
• Est. Priority Date: 04/15/2010
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Kishi, Atsushi, Takemoto, Hiroyuki
• Granted Patent: US 9,182,522 B2
• Time in Patent Office: Days
• US Class Current: 428/212
• CPC Class Codes: B32B 17/10 of synthetic resin
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 2201/50 Protective arrangements
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

The present invention provides a hard coat film in which the generation of interference fringes can be reliably prevented. The hard coat film 1 of the present invention includes a transparent film 2 and a hard coat layer 3 provided on the transparent film 2, wherein an interface 5 that can be detected to form by a reflection spectrum analysis exists between the transparent film 2 and the hard coat layer 3, and a refractive index continuously varies in the thickness direction in a region 31 from the interface 5 to a thickness-wise middle part of the hard coat layer 3 without forming an interface that can be detected by the reflection spectrum analysis.

Claims

1. A hard coat film, comprising:

a transparent film; and

a hard coat layer provided on the transparent film;

wherein an interface that can be detected by a reflection spectrum analysis exists between the transparent film and the hard coat layer, and a refractive index continuously varies in the thickness direction in a region from the interface to a thickness-wise middle part of the hard coat layer without forming an interface that can be detected by the reflection spectrum analysis.

3. The hard coat film according to claim 1, wherein the hard coat layer has a thickness of 3 μ

m to 15 μ

m.

4. The hard coat film according to claim 1, further comprising an antireflection layer provided on a surface of the hard coat layer.

5. The hard coat film according to claim 1, wherein a transparent film-forming component and a hard coat layer-forming component are present in a region from the interface to a thickness-wise middle part of the transparent film, and the transparent film-forming component in the region decreases toward a surface of the hard coat layer.

6. A polarizing plate comprising the hard coat film according to claim 1.

7. An image display device comprising the hard coat film according to claim 1.

2. A hard coat film, comprising:

a transparent film; and

a hard coat layer provided on the transparent film;

wherein an interface that can be detected by a reflection spectrum analysis exists between the transparent film and the hard coat layer, a transparent film-forming component and a hard coat layer-forming component are present in a region from the interface to a thickness- wise middle part of the hard coat layer, and the transparent film-forming component in the region decreases toward a surface of the hard coat layer without forming an interface that can be detected by the reflection spectrum analysis.

8. A method for producing a hard coat film, comprising:

a coating film-forming step of applying a hard coat layer-forming material onto a transparent film to form a coating film having a predetermined thickness, the hard coat layer-forming material including a curable compound containing a low molecular-weight component with a molecular weight of 800 or less and a solvent containing a good solvent for the transparent film; and

a curing step of curing the coating film to form a hard coat layer on the transparent film;

wherein the low molecular-weight component and good solvent contained in the hard coat layer-forming material and the thickness of the coating film satisfy the relationships of the following formulae 1 and 2;

Y≧

−

4.274 In (X)+11.311  

 

Formula 1;

Y≦

−

4.949 In (X)+15.474,  

 

Formula 2;

in the formula,

the “

Y”

represents b×

t,

the “

X”

represents a×

t,

the “

a”

represents the content ratio of the low molecular-weight component based on the total amount of the curable compound taken as 1,

the “

b”

represents the content ratio of the good solvent based on the total amount of the hard coat layer-forming material taken as 1, and

the “

t”

represents the thickness μ

m of the coating film.

9. The method for producing the hard coat film according to claim 8, wherein the “

a”

is more than 0.3 and 1 or less and the “

b”

is 0.05 or more and 0.5 or less.

10. The method for producing the hard coat film according to claim 8, wherein the low molecular-weight component is a UV-curable resin monomer or oligomer.