KR20160033367A - Norbornene optical film with excellent slip property - Google Patents

Abstract

The present invention relates to a norbornene optical film with an excellent slip property and, more specifically, to a norbornene optical film having 50-500nm of Rth and 10-400nm of Ro, which are expressed in the formulas (1) and (2) below. The norbornene optical film includes a slip layer, of which dynamic friction factor is not more than 0.7, at least in one surface. The film of the present invention does not have the degradation of haze and has an excellent slip property. The formula (1) is Rth = {(nx+ny)/2-nz} x d. The formula (2) is Ro = (nx-ny) x d. At this point, d is the thickness of the film, nx is an in-plane refractive index of the film, ny is an in-plane refractive index of the film in an orthogonal direction to nx, and nz is a refractive index of the film in a thickness direction. Each one is based on a value, measured in a condition with 23°C and 55%RH at 550nm of wavelength.

Description

NORBORNENE OPTICAL FILM WITH EXCELLENT SLIP PROPERTY "

The present invention relates to a norbornene-based optical film excellent in slipperiness.

The norbornene-based resin optical film has an advantage of excellent phase retardation characteristics. However, since the resin is very sticky, the friction coefficient of the film surface is very high and slip property is not good. That is, if the slip is poor, the film is pressed between the films after winding, and the surface is damaged and scratches are generated, resulting in quality defects.

A conventional technique for improving poor slip properties in the production of a norbornene-based film can be exemplified in Patent Document 1 below. Patent Document 1 discloses a method for producing an optical film which forms a fine structure on the surface of the thermoplastic resin film by pressing a molten extruded thermoplastic resin film 6 with a metal mold endless belt with a metal roll 2, Tg, the metallic endless belt at a temperature of Tg + 40 占 폚 has a coefficient of dynamic friction with the thermoplastic resin film of 0.3 or less and a surface roughness Ra of the surface of the metallic endless belt 3 of 0.2 占 퐉 or less. .

JP 2012-045914 A (Mar.

It is an object of the present invention to provide a norbornene-based optical film capable of improving the coefficient of dynamic friction without deteriorating the haze characteristics and improving the surface damage and the quality defects such as scratches of the conventional norbornene-based resin optical film.

The present invention has been made to solve the problems of the prior art,

A norbornene-based optical film having Rth of 50 to 500 nm and Ro of 10 to 400 nm represented by the following formulas (1) and (2), wherein at least one surface of the film is provided with a slip layer having a coefficient of dynamic friction of 0.7 or less Based on the total weight of the norbornene-based optical film.

Rth = {(nx + ny) / 2-nz} xd (1)

(2) Ro = (nx-ny) xd

Here, d is the thickness of the film, nx is the refractive index in the plane of the film, ny is the refractive index in the direction perpendicular to nx in the plane of the film, and nz is the refractive index of the film in the thickness direction. Is a reference measured at a wavelength of 550 nm.

In the present invention, the slip layer is formed by adhering a masking film of at least one material selected from polyethylene, polyethylene terephthalate, and nylon having a thickness within a range of 10 to 100 mu m. The norbornene- to provide.

In the present invention, the slip layer is formed by coating fine particles within a range of 0.05 to 3 mu m in thickness, and provides the norbornene-based optical film.

The film of the present invention has an excellent slip property even when there is no decrease in haze.

Hereinafter, the present invention will be described in detail.

According to the present invention,

A norbornene-based optical film having Rth of 50 to 500 nm and Ro of 10 to 400 nm represented by the following formulas (1) and (2), wherein at least one surface of the film is provided with a slip layer having a coefficient of dynamic friction of 0.7 or less Based on the total weight of the norbornene-based optical film.

Rth = {(nx + ny) / 2-nz} xd (1)

(2) Ro = (nx-ny) xd

Here, d is the thickness of the film, nx is the refractive index in the plane of the film, ny is the refractive index in the direction perpendicular to nx in the plane of the film, and nz is the refractive index of the film in the thickness direction. Is a reference measured at a wavelength of 550 nm.

The slip layer may be formed by laminating a masking film on at least one side of the norbornene-based optical film. The material of the masking film is not particularly limited, but may be selected from polyethylene, polyethylene terephthalate, and nylon One or more species may be used without limitation.

When the slip layer is formed by the masking film, the thickness of the slip layer is preferably in the range of 10 to 100 mu m. If it is less than 10, it may easily cause wrinkles at the time of bonding. If it is more than 100, it may cause curl due to expansion and contraction of the slip layer.

The slip layer may be formed by coating fine particles on at least one side of the norbornene-based optical film.

When the slip layer is formed by coating the fine particles, it is preferable that the thickness of the slip layer is within the range of 0.05 to 3 mu m. When the thickness is less than 0.05 탆, the thickness of the fine particle layer is low and it may be difficult to apply uniformly, and a region where the fine particle layer is not partially applied may occur, and the coefficient of dynamic friction may increase. If the particle size exceeds 3 mu m, coagulation between the fine particles occurs, which may lower the coefficient of dynamic friction. However, if the surface flatness is lowered and the haze of the film increases, Thereby causing a foreign object.

Hereinafter, the present invention will be described in more detail by way of examples. It is to be understood that the following embodiments are for the purpose of illustration only and are not intended to limit the scope of the present invention.

Example

Example  One

24% by weight of a norbornene resin solid content, and a solvent (methylene chloride: methanol = 9: 1) were put into a mixing tank and stirred to dissolve completely. The dissolved dope solution was used to prepare a norbornene-based film. The film was stretched 130% at a stretching temperature of 170 DEG C and laminated with a low-adhesion polyethylene protective film having a thickness of 50 mu m on one side of the dried film (the thickness of the formed retardation film was 40 mu m) at a drying temperature of 110 DEG C (40 minutes) , And finally the film was completed.

Example  2

24% by weight of a norbornene resin solid content, and a solvent (methylene chloride: methanol = 9: 1) were put into a mixing tank and stirred to dissolve completely. The dissolved dope solution was used to prepare a norbornene-based film. (90% by weight) of silica (90% by weight) and water-based polymer (100% by weight) on one side of the dried film (thickness of the formed retardation film was 40 탆) at a drying temperature of 110 캜 Binder (10% by weight)) was coated thereon, and then thermosetting surface treatment was performed to finally complete the film.

Example  3

24% by weight of a norbornene resin solid content, and a solvent (methylene chloride: methanol = 9: 1) were put into a mixing tank and stirred to dissolve completely. The dissolved dope solution was used to prepare a norbornene-based film. (90% by weight) of silica (90% by weight) and an acrylate (90% by weight) were laminated on one side of the dried film (thickness of the formed retardation film was 40 탆) at a drying temperature of 110 캜 Based binder (10 wt%)), and then thermally cured to obtain a final film.

Comparative Example  One

A norbornene resin solid content of 24% by weight, silica of 0.2% by weight, and a solvent (methylene chloride: methanol = 9: 1) were put into a mixing tank and stirred to completely dissolve. The dissolved dope solution was used to prepare a norbornene-based film. The film was stretched 130% at a stretching temperature of 170 占 폚 and dried at a drying temperature of 110 占 폚 (40 minutes) to finally complete a film.

Comparative Example  2

A norbornene resin solid content of 24% by weight, silica of 0.4% by weight, and a solvent (methylene chloride: methanol = 9: 1) were put into a mixing tank and stirred to dissolve completely. The dissolved dope solution was used to prepare a norbornene-based film. The film was stretched 130% at a stretching temperature of 170 占 폚 and dried at a drying temperature of 110 占 폚 (40 minutes) to finally complete a film.

Comparative Example  3

A norbornene resin solid content of 24% by weight, silica of 0.6% by weight, and a solvent (methylene chloride: methanol = 9: 1) were put into a mixing tank and stirred to dissolve completely. The dissolved dope solution was used to prepare a norbornene-based film. The film was stretched 130% at a stretching temperature of 170 占 폚 and dried at a drying temperature of 110 占 폚 (40 minutes) to finally complete a film.

Experimental Example  - Hayes  And Coefficient of friction  Measure

The haze of the film was measured using a hazemeter, and the coefficient of dynamic friction was measured using a friction coefficient measuring device. The measurement environment is 23 캜, 55% RH.

The results are shown in Table 1.

As shown in Table 1, in the case of mixing the silica particles together in the dope, the dynamic friction coefficient is not improved even when the silica content is increased, and only the disadvantage that the haze of the optical film is increased becomes rather high. On the other hand, in Examples 1, 2 and 3, it is found that the haze characteristics are excellent and the surface slip property is secured.

Claims (3)

A norbornene-based optical film having Rth of 50 to 500 nm and Ro of 10 to 400 nm represented by the following formulas (1) and (2), wherein at least one surface of the film is provided with a slip layer having a coefficient of dynamic friction of 0.7 or less Based on the total weight of the norbornene-based optical film.
Rth = {(nx + ny) / 2-nz} xd (1)
(2) Ro = (nx-ny) xd
Here, d is the thickness of the film, nx is the refractive index in the plane of the film, ny is the refractive index in the direction perpendicular to nx in the plane of the film, and nz is the refractive index of the film in the thickness direction. Is a reference measured at a wavelength of 550 nm. The norbornene-based optical film according to claim 1, wherein the slip layer is formed by adhering a masking film of at least one material selected from polyethylene, polyethylene terephthalate, and nylon having a thickness within a range of 10 to 100 μm. The norbornene-based optical film according to claim 1, wherein the slip layer is coated with fine particles within a range of 0.05 to 3 μm in thickness.