TW202241705A - Optical film - Google Patents

Abstract

The purpose of the present invention is to provide an optical film that is excellent in terms of the low moisture permeability thereof and suitable for a polarizing plate protective film. This optical film 10 has a layered structure in which a resin layer 1 is layered on one surface of a light-transmitting substrate 2. The resin layer 1 is formed from a cured product of a curable composition containing at least one type of polymerizable compound selected from the group consisting of monomers having a polymerizable functional group and oligomers having a polymerizable functional group. When the moisture permeability M1[g/m2.24h] of the optical film in an environment with a temperature of 40 DEG C and a relative humidity of 92% is subtracted from 1,000 and the result is divided by the thickness T ([mu]m) of the resin layer, the resulting value ((1,000 - M1)/T) is 100 or more.

Description

Optical film

The invention relates to an optical film. Specifically, it relates to an optical film suitable for a protective film of a polarizing plate.

In image display devices (such as liquid crystal display devices, organic EL display devices, etc.), due to the image forming method, in most cases, a polarizer is disposed on at least one side of the display unit. The polarizing plate has the function of only passing light with a fixed polarization plane, and the performance of the image display device will be greatly affected by the performance of the polarizing plate. A polarizer is generally composed of a polarizer and a transparent protective film (polarizer protective film) on at least one side of the polarizer, wherein the polarizer is made of polyvinyl alcohol film that has made iodine or dye adsorption and orientation Those (for example, Patent Document 1). prior art literature patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2000-338329

The problem to be solved by the invention In recent years, the market for mobile terminals such as smartphones and tablet computers has expanded, and the demand for thinner image display devices has also increased, and polarizer protective films and other components that constitute polarizers have also been required to be thinner. However, there is a problem that as the thickness of the polarizer protective film becomes thinner, the protection function for the polarizer decreases.

For example, if the polarizing plate protective film becomes thinner, the moisture permeability (moisture permeability) will increase, and the polarizing performance of the polarizer will disappear in a humid environment, so the so-called "fading" phenomenon may occur.

The present invention was conceived based on the circumstances described above, and an object of the present invention is to provide an optical film that has excellent low moisture permeability even if it is thinned and is suitable for a polarizing plate protective film.

In addition, if the polarizing plate protective film becomes thinner, the surface hardness and scratch resistance will decrease, and the polarizing plate will be easily damaged in the manufacturing process, and the performance of the polarizing plate will decrease due to low moisture permeability. Therefore, excellent scratch resistance is also required for optical films used for polarizing plate protective films.

means to solve problems That is, the first or second aspect of the present invention provides an optical film in which a resin layer is layered on one surface of a light-transmitting substrate. The aforementioned resin layer is one that imparts excellent low moisture permeability to the optical film of the first or second aspect of the present invention. In addition, the above-mentioned resin layer is also one that imparts excellent scratch resistance to the optical film of the first or second aspect of the present invention. Therefore, the optical film of the first or second aspect of the present invention having the aforementioned resin layer in a laminated structure is suitable for a polarizing plate protective film.

In the optical film according to the first or second aspect of the present invention, the aforementioned resin layer is formed of a hardened product of a curable composition, and the curable composition is selected from monomers having polymerizable functional groups and polymerizable At least one polymerizable compound in the group consisting of oligomers of functional groups. This constitution is very good in imparting excellent low moisture permeability to the optical film of the first or second aspect of the present invention. Moreover, it is also preferable in imparting excellent scratch resistance to the optical film of the first or second aspect of the present invention.

In the optical film according to the first aspect of the present invention, the moisture permeability M ¹ [g/m ₂ ·24h] of the optical film at a temperature of 40°C and a relative humidity of 92% is subtracted from 1,000, and the obtained value is divided by the resin The value ((1,000-M ¹ )/T) after the thickness T [µm] of the layer is 100 or more. The configuration in which the aforementioned value ((1,000-M ¹ )/T) is 100 or more is ideal in that when the optical film according to the first aspect of the present invention is used as a polarizer protective film, even if the aforementioned resin layer is thin, Even under certain conditions, it can still suppress the "fading" of the polarizer in a humid environment. From the standpoint of suppressing discoloration of the polarizer and reducing the thickness of the resin layer at a higher level, the above-mentioned value ((1,000-M ¹ )/T) is preferably 105 or more, more preferably 110 or more, or may be 115 or more.

In the optical film according to the second aspect of the present invention, the moisture permeability M ² [g/m ² ·24h] of the optical film at a temperature of 60°C and a relative humidity of 90% is subtracted from 2,000, and the obtained value is divided by the resin The value ((2,000-M ² )/T) after the layer thickness T [µm] is 200 or more. The configuration in which the aforementioned value ((2,000-M ² )/T) is 200 or more is ideal in that when the optical film according to the second aspect of the present invention is used as a polarizer protective film, even if the aforementioned resin layer is thin, Even under certain conditions, it can still suppress the "fading" of the polarizer in a humid environment. From the standpoint of suppressing discoloration of the polarizer and reducing the thickness of the resin layer at a higher level, the above-mentioned value ((2,000-M ² )/T) is preferably 210 or more, more preferably 220 or more, or may be 230 or more.

In the optical film of the first or second aspect of the present invention, the product of the aforementioned value ((1,000-M ¹ )/T) and the aforementioned value ((2,000-M ₂ )/T) [((1,000-M ¹ )/T )×((2,000-M ² )/T)] is preferably 20,000 or more. The aforementioned product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is more than 20,000 is ideal in view of the following aspects: the first or second aspect of the present invention optical When the film is used as a protective film for polarizers, even if the above-mentioned resin layer is thin, it can still suppress the "fading" of the polarizer in a humid environment. From the standpoint of suppressing discoloration of the polarizer at a higher level and reducing the thickness of the resin layer, the above product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is preferable. It is more than 21,000, preferably more than 22,000.

The optical film of the first or second aspect of the present invention should be free from scratches after the scratch resistance test is carried out on the surface of the resin layer with steel wool under the conditions of a load of 0.98N, a moving speed of 100mm/sec, and 10 times of reciprocation. As mentioned above, the above-mentioned resin layer also imparts excellent scratch resistance to the optical film of the first or second aspect of the present invention. Therefore, when the optical film of the first or second aspect of the present invention is used as a polarizing plate protective film, since the above-mentioned resin layer has excellent scratch resistance, it is less likely to be damaged in the production process, and the decrease in low moisture permeability can be suppressed. The performance of the polarizer decreases.

In the optical film of the first or second aspect of the present invention, the film thickness of the aforementioned resin layer is preferably 0.5-6 µm. As described above, even if the aforementioned resin layer is thinned, excellent low moisture permeability can be imparted to the optical film according to the first aspect of the present invention. When the optical film of the first or second aspect of the present invention is used as a polarizing plate protective film, the film thickness of the aforementioned resin layer is preferably 5.8 µm or less, more preferably 5.6 µm, from the viewpoint of making the polarizing plate thinner the following. From the standpoint of achieving both low moisture permeability and scratch resistance at a higher level, the lower limit of the film thickness of the aforementioned resin layer is preferably 1 µm or more, and may be 2 µm or more.

In the optical film according to the first aspect of the present invention, the above-mentioned light-transmitting base material preferably contains at least 1 selected from the group consisting of cellulose-based resins, polyester-based resins, acrylic resins, and cyclic olefin-based polymers. kind. These resins can be suitably used as base materials for polarizing plate protective films.

Furthermore, the third aspect of the present invention provides a polarizing plate in which a polarizer is disposed on the side opposite to the resin layer of the optical film of the first or second aspect of the present invention. Furthermore, the fourth aspect of the present invention provides an image display device having the polarizing plate of the third aspect of the present invention. In the image display device according to the fourth aspect of the present invention, an adhesive layer and an optical member are preferably sequentially laminated on the aforementioned resin layer.

In the polarizing plate of the third aspect of the present invention, the optical film of the first or second aspect of the present invention is used as a polarizing plate protective film, so the above-mentioned resin layer has excellent low moisture permeability and scratch resistance even if it is thin. Therefore, even if the image display device of the fourth aspect of the present invention having the polarizing plate of the third aspect of the present invention is thin, it is difficult to cause discoloration of the polarizing plate in a humid environment, and has excellent durability.

Invention effect The polarizing plate obtained by using the optical film of the present invention as a polarizing plate protective film has excellent low moisture permeability even if it is thinned, is less prone to fading of the polarizing element, and has excellent durability.

The first or second aspect of the present invention provides an optical film in which a resin layer is layered on one surface of a light-transmitting substrate. In this specification, the optical film of the first aspect of the present invention may be referred to as "optical film A"; in this specification, the optical film of the second aspect of the present invention may be referred to as "optical film B". In addition, the optical film A and the optical film B may be collectively referred to as "the optical film of the present invention". In addition, in this specification, the aforementioned resin layer constituting the optical film A may be referred to as "resin layer A", the aforementioned resin layer constituting the optical film B may be referred to as "resin layer B", and the resin layer may be referred to as "resin layer A". Layer A and resin layer B are collectively referred to as "the resin layer of the present invention". In addition, the aforementioned light-transmitting substrate constituting the optical film of the present invention may be referred to as "the light-transmitting substrate of the present invention". In addition, the term "film" includes the meanings of "sheet" and "ribbon". That is, the optical film of the present invention may have a sheet-like or tape-like form.

The third aspect of the present invention provides a polarizing plate in which a polarizer is disposed on the side opposite to the resin layer of the optical film of the present invention. In this specification, the polarizing plate of the third aspect of the present invention may be referred to as "the polarizing plate of the present invention". Moreover, the fourth aspect of the present invention provides an image display device comprising the polarizing plate of the present invention. In this specification, the video display device according to the fourth aspect of the present invention may be referred to as "the video display device of the present invention".

Hereinafter, embodiments of the optical film of the present invention will be described with reference to the drawings, but the present invention is not limited thereto and is merely an example.

FIG. 1 is a schematic diagram (sectional view) showing an embodiment of the optical film of the present invention. In FIG. 1 , an optical film 10 has a laminated structure in which a resin layer 1 is layered on one surface of a light-transmitting substrate 2 .

Fig. 2 is a schematic diagram (sectional view) showing an embodiment of a polarizing plate of the present invention. In FIG. 2 , a polarizer 20 has a laminated structure in which a polarizer 3 is disposed on the opposite side of the optical film 10 to the resin layer 1 . In the present embodiment, the second light-transmitting base material 4 and the adhesive layer 5 are further laminated sequentially on the opposite side of the optical film 10 of the polarizer 3 .

FIG. 3 is a schematic view (sectional view) showing an embodiment of an image display device having the polarizing plate shown in FIG. 2 . In the image display device 30 of FIG. 3 , the image display panel 6 is laminated on the adhesive layer 5 of the polarizing plate 20 . In this embodiment, the adhesive layer 7 and the optical member 8 are sequentially laminated on the resin layer 1 . Each configuration will be described below.

＜Optical Film＞ The "optical" of the optical film of the present invention means that it can be used for optical purposes, more specifically, it means that it can be used for the manufacture of products (optical products) using optical members, and the like. Optical products can be, for example, image display devices, input devices such as touch panels, etc., and can be suitably used in the manufacture of liquid crystal image display devices, self-luminous image display devices (such as organic EL (electroluminescent) image display devices, LED image display devices, etc.) device), etc. More specifically, it can be suitably used as a protective film of a polarizing plate constituting an image display device.

The form of the optical film of the present invention is not particularly limited as long as a resin layer is layered on one surface of the light-transmitting substrate. For example, the optical film of the present invention may have a resin layer on only one side, or may have a resin layer on both sides. Also, when the optical film of the present invention has resin layers on both sides, the optical film of the present invention may have a form in which the two resin layers are provided by the resin layer of the present invention, or may have one of the resin layers provided by the resin layer of the present invention and the other resin layer. It is a form provided by a resin layer (other resin layer) other than the resin layer of the present invention. When the optical film of the present invention is used as a polarizing plate protective film, it is preferably an optical film having a resin layer on only one side.

In addition to the light-transmitting substrate of the present invention and the resin layer of the present invention, the optical film of the present invention may also have other layers on the surface or between arbitrary layers, such as the light-transmitting substrate of the present invention, within the scope of not impairing the effects of the present invention. Substrates other than the resin layer of the present invention, resin layers other than the resin layer of the present invention, intermediate layers, primer layers, antistatic layers, separators, surface protection films, etc.

In the optical film A of the present invention, the moisture permeability M ¹ [g/m ² ·24h] of the optical film A at a temperature of 40°C and a relative humidity of 92% is subtracted from 1,000, and the obtained value is divided by the resin layer A The value after the thickness T[µm] ((1,000-M ¹ )/T) is 100 or more. The resin layer A of the present invention imparts excellent low moisture permeability to the optical film A of the present invention. Generally speaking, the thicker the film, the higher the moisture permeability, and the thinner the film, the lower the moisture permeability. The above value "1,000" is the predicted value of the moisture permeability of the light-transmitting substrate itself (light-transmitting substrate without resin layer A) of the present invention at a temperature of 40°C and a relative humidity of 92%. Subtract the moisture permeability from 1,000. The obtained value of the humidity M ¹ [g/m ² ·24h] is the predicted value of the water vapor transmission rate lowered by disposing the resin layer A on the light-transmitting substrate of the present invention. Therefore, the above-mentioned value ((1,000-M ¹ )/T) can be used as an indicator of the water vapor transmission rate of the resin layer A of the present invention per 1 µm in thickness at a temperature of 40°C and a relative humidity of 92%. The higher it is, the lower it is The more excellent the moisture permeability. Therefore, the optical film A having the resin layer A of the present invention having the above-mentioned value ((1,000-M ¹ )/T) of 100 or more in the laminated structure can provide excellent low moisture permeability even if the resin layer A is thinned, and becomes a dual-purpose film. Thinner and excellent low moisture permeability.

The configuration in which the aforementioned value ((1,000-M ¹ )/T) is 100 or more is ideal in that when the optical film A of the present invention is used as a polarizer protective film, even when the resin layer A of the present invention is thin It can still impart excellent low moisture permeability even under high humidity, and can suppress the "fading" of the polarizer in a humid environment. From the standpoint of suppressing the discoloration of the polarizer at a higher level and reducing the thickness of the resin layer A of the present invention, the aforementioned value ((1,000-M ¹ )/T) is preferably 105 or more, more preferably 110 or more, or Can be 115 or more. The upper limit of the aforementioned value ((1,000-M ¹ )/T) is not particularly limited. From the viewpoint of preventing the "fading" of the polarizer due to the moisture in the polarizing plate detaching to the outside, it is preferably 500 or less. 400 or less, or 300 or less.

In the optical film B of the present invention, the moisture permeability M ² [g/m ² ·24h] of the optical film B at a temperature of 60°C and a relative humidity of 90% is subtracted from 2,000, and the obtained value is divided by the resin layer B The value ((2,000-M ² )/T) after the thickness T[µm] is 200 or more. The resin layer B of the present invention imparts excellent low moisture permeability to the optical film B of the present invention. Generally speaking, the thicker the film, the higher the moisture permeability, and the thinner the film, the lower the moisture permeability. The above value "2,000" is the predicted value of the moisture permeability of the light-transmitting substrate itself (light-transmitting substrate without resin layer B) of the present invention at a temperature of 60°C and a relative humidity of 90%, and the moisture permeability is subtracted from 2,000. The obtained value of the humidity M ² [g/m ² ·24h] is the predicted value of the water vapor transmission rate lowered by disposing the resin layer B on the light-transmitting substrate of the present invention. Therefore, the above-mentioned value ((2,000-M ² )/T) can be used as an indicator of the water vapor transmission rate of the resin layer B of the present invention per 1 µm in thickness at a temperature of 60°C and a relative humidity of 90%. The higher it is, the lower it is. The more excellent the moisture permeability. Therefore, the optical film B having the above-mentioned value ((2,000-M ² )/T) of the resin layer B of the present invention of 200 or more in the laminated structure can provide excellent low moisture permeability even if the resin layer B is thinned, and becomes a combination film. Thinner and excellent low moisture permeability.

The configuration in which the aforementioned value ((2,000-M ² )/T) is 200 or more is ideal in that when the optical film B of the present invention is used as a polarizer protective film, even when the resin layer B of the present invention is thin It can still impart excellent low moisture permeability even under high humidity, and can suppress the "fading" of the polarizer in a humid environment. From the standpoint of suppressing the discoloration of the polarizer and reducing the thickness of the resin layer B of the present invention at a higher level, the aforementioned product value ((2,000-M ² )/T) is preferably 210 or more, more preferably 220 or more, It can also be 230 or more. The upper limit of the aforementioned value ((2,000-M ² )/T) is not particularly limited, but it is preferably 1,000 or less from the viewpoint of preventing "fading" of the polarizer due to the moisture in the polarizing plate leaving to the outside. It may be 800 or less, or may be 500 or less.

In the optical film A or B of the present invention, the product of the aforementioned value ((1,000-M ¹ )/T) and the aforementioned value ((2,000-M ² )/T) [((1,000-M ¹ )/T)×(( 2,000-M ² )/T)] is preferably 20,000 or more. The aforementioned product [(1,000-M ¹ )/T)×((2,000-M ² )/T)] is also related to the aforementioned value (1,000-M ¹ )/T), the aforementioned value ((2,000-M ² )/T) Similarly, it can be used as an indicator of the moisture permeability of the resin layer (resin layer A or B) of the present invention itself, and the higher it is, the better the low moisture permeability. Therefore, the optical film A or the optical film of the present invention having the resin layer A or B of the present invention having the product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] of 20,000 or more in the laminated structure B Even if the resin layer A or B of the present invention is thinner, excellent low moisture permeability can be imparted, and it is desirable that it has both thinning and excellent low moisture permeability.

The aforementioned product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is 20,000 or more is ideal in the following respects: the optical film A or B of the present invention is used as a polarizing plate When the protective film is used, even if the resin layer A or B of the present invention is thin, it can still suppress the "fading" of the polarizer in a humid environment. From the point of view of suppressing the fading of the polarizer at a higher level and reducing the thickness of the resin layer A or B of the present invention, the above product [((1,000-M ¹ )/T)×((2,000-M ² )/ T)] is preferably at least 21,000, more preferably at least 22,000. The above-mentioned upper limit of [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is not particularly limited, to prevent the "fading" of the polarizer from the moisture in the polarizer to the outside From this point of view, it is preferably less than 200,000, more preferably less than 150,000, and may be less than 120,000.

In the optical film of the present invention (optical film A or B), the moisture permeability M ³ [g/m ² ·24h] of the optical film at a temperature of 65°C and a relative humidity of 90% is subtracted from 2,700, and the obtained value is divided by The value ((2,700-M ³ )/T) based on the thickness T [µm] of the aforementioned resin layer (resin layer A or B) is preferably 250 or more. The above value "2,700" is the predicted value of the moisture permeability of the light-transmitting substrate itself (light-transmitting substrate without resin layer A or B) of the present invention at a temperature of 65°C and a relative humidity of 90%. Subtract from 2,700 The value obtained by removing the water vapor transmission rate M ³ [g/m ² ·24h] is the predicted value of the water vapor transmission rate lowered by disposing the resin layer A or B on the light-transmitting substrate of the present invention. Therefore, the above-mentioned value ((2,700-M ³ )/T) can be used as an indicator of the water vapor transmission rate of the resin layer A or B of the present invention per 1 μm thickness in an environment with a temperature of 65°C and a relative humidity of 90%. The higher the value, the higher the value. It can be said that the lower the moisture permeability, the better. Therefore, the optical film A or B having the resin layer A or B of the present invention having the above-mentioned value ((2,700-M ³ )/T) of 250 or more in a laminated structure can provide excellent low-temperature film even if the resin layer A or B becomes thinner. Moisture permeability has become both thin and excellent low moisture permeability.

The aforementioned value ((2,700-M ³ )/T) of 250 or more is ideal in that when the optical film A or B of the present invention is used as a polarizer protective film, even if the resin layer A or B of the present invention Even when B is thin, it can still impart excellent low moisture permeability, and can suppress the "fading" of the polarizer in a humid environment. From the standpoint of suppressing discoloration of the polarizer at a higher level and reducing the thickness of the resin layer A or B of the present invention, the aforementioned value ((2,700-M ³ )/T) is preferably 270 or more, more preferably 280 or more , can also be more than 300. The upper limit of the aforementioned value ((2,700-M ³ )/T) is not particularly limited, but from the viewpoint of preventing “fading” of the polarizer due to moisture in the polarizing plate detaching to the outside, it is preferably 1,000 or less. It may be 800 or less, or may be 600 or less.

The moisture permeability M ¹ [g/m ² ·24h] of the optical film A of the present invention is preferably below 700g/m ² ·24h at a temperature of 40°C and a relative humidity of 92%. The aforementioned constitution in which the moisture permeability M1 is 700 g/m ^{2 ·} 24h or less is ideal in the following respects: when the optical film A of the present invention is used as a polarizer protective film, it is possible to suppress occurrence of ""fade". From the viewpoint of suppressing the fading of the polarizer at a higher level, the aforementioned moisture permeability M1 is preferably 600 g/m ² ·24h or less, and may be 550 g/m ^{2 ·} 24h or less. The lower limit of the above ^- mentioned moisture permeability M1 is not particularly limited. From the viewpoint of preventing the moisture in the polarizing plate from leaving to the outside and causing the "fading" of the polarizing element, it is preferably 100g/m2 ^· 24h or more, more preferably 200g /m ² ·24h or more, or 300g/m ² ·24h or more.

The moisture permeability M ² [g/m ² ·24h] of the optical film B of the present invention is preferably below 1,500g/m ² ·24h at a temperature of 60°C and a relative humidity of 90%. The aforementioned constitution in which the water vapor transmission rate ^M2 is 1,500 g/m ² ·24h or less is ideal in that when the optical film B of the present invention is used as a polarizer protective film, it is possible to suppress the generation of the polarizer in a humid environment. "fade". From the viewpoint of suppressing the fading of the polarizer at a higher level, the aforementioned moisture permeability M2 is preferably 1,400g/m ² ·24h or less, more preferably 1,300g/m ² ·24h or less, or 1,200g/m ² ·24h or less. m ²・24h or less. The lower limit of the above-mentioned moisture permeability ^M2 is not particularly limited. From the viewpoint of preventing the moisture in the polarizing plate from leaving to the outside and causing the "fading" of the polarizing element, it is preferably 300g/m2 ^· 24h or more, more preferably 500g /m ² ·24h or more, or 800g/m ² ·24h or more.

The moisture permeability M ³ [g/m ² ·24h] of the optical film A or B of the present invention is preferably below 2,000g/m ² ·24h at a temperature of 65°C and a relative humidity of 90%. The aforementioned constitution in which the moisture permeability M3 is 2,000g/ ^{m2 ·} 24h or less is ideal in that when the optical film A or B of the present invention is used as a polarizer protective film, it can suppress the occurrence of polarization in a humidified environment The "fading" of the piece. From the viewpoint of suppressing the fading of the polarizer at a higher level, the aforementioned moisture permeability M3 is preferably 1,800g/m ² ·24h or less, more preferably 1,600g/m ² ·24h or less, or 1,400g/m ² ·24h or less. m ²・24h or less. ^The lower limit of the above-mentioned moisture permeability M3 is not particularly limited. From the viewpoint of preventing the moisture in the polarizing plate from leaving to the outside and causing the "fading" of the polarizing element, it is preferably 500g/m2 ^· 24h or more, more preferably 750g /m ² ·24h or more, or 1,000g/m ² ·24h or more.

The aforementioned moisture permeability M ¹ , M ² , M ³ and the value ((1,000-M ¹ )/T), value ((2,000-M ² )/T), value ( (2,700-M ³ )/T) and their products can be specifically measured by the method described in the examples below. The aforementioned moisture permeability M ¹ , M ² , M ³ of the optical film of the present invention and the value ((1,000-M ¹ )/T), value ((2,000-M ² )/T), value ((2,700-M ³ )/T T) and the product thereof can be adjusted by adjusting the type or thickness of the resin constituting the light-transmitting substrate of the present invention, the type, composition, and degree of crosslinking of the resin constituting the resin layers (resin layers A and B) of the present invention. Wait to adjust.

The haze of the optical film of the present invention is not particularly limited, but from the viewpoint of obtaining good transparency, it is preferably 1.0% or less, more preferably 0.8% or less. The haze can be obtained in accordance with JIS K 7136 (2000). The haze of the optical film of the present invention can be adjusted by the type or thickness of the resin constituting the light-transmitting substrate of the present invention, the type or thickness of the resin constituting the resin layer of the present invention, and the like.

The total light transmittance of the optical film of the present invention in the visible light wavelength region is not particularly limited, but is preferably above 85%, more preferably above 88%. The visible light wavelength region can be obtained in accordance with JIS K 7361-1. The total light transmittance of the optical film of the present invention can be adjusted by the type or thickness of the resin constituting the light-transmitting base material of the present invention, the type or thickness of the resin constituting the resin layer of the present invention, and the like.

The thickness of the optical film of the present invention is not particularly limited. For example, considering aspects such as thinness, strength, handling, etc., it is suitable for the range of 1~500µm, more suitable for the range of 10~300µm, most suitable for 20~200µm range.

＜Light-transmitting base material＞ The material constituting the light-transmitting substrate of the present invention may be glass or plastic film. Examples of the aforementioned plastic film include cellulose resins such as cellulose triacetate (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate, etc. Polyester-based resins such as ethylene glycol (PEN), cyclic olefin-based polymers (COP) (for example, trade name "ARTON" (manufactured by JSR Co., Ltd.), trade name "ZEONOR" (manufactured by Zeon Co., Ltd.), etc. ), polycarbonate resin, polysulfide resin, polyarylate, polyimide resin, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer and other plastic materials; In terms of optical uniformity, smooth surface, and good secondary processability in making polarizing plates, cellulose-based resins, acrylic resins, polyester-based resins, and cyclic olefin-based polymers (COP) are preferred, especially Preferably, it is a cellulose-based resin. In addition, these plastic materials can be used individually or in combination of 2 or more types.

The haze of the light-transmitting substrate of the present invention is not particularly limited, but from the viewpoint of obtaining good transparency, it is preferably 1.0% or less, more preferably 0.8% or less. The haze can be obtained in accordance with JIS K 7136 (2000). The haze of the light-transmitting base material of the present invention can be adjusted by the type and thickness of the resin constituting the light-transmitting base material of the present invention.

The total light transmittance of the light-transmitting substrate of the present invention in the visible light wavelength region is not particularly limited, but is preferably 85% or more, more preferably 88% or more. The visible light wavelength region can be obtained in accordance with JIS K 7361-1. The total light transmittance of the light-transmitting substrate of the present invention can be adjusted by the type and thickness of the resin constituting the light-transmitting substrate of the present invention.

The thickness of the light-transmitting substrate of the present invention is not particularly limited. For example, considering the thin layer, strength, handleability and other aspects of workability and thin layer, it is preferably in the range of 1~500µm, more preferably in the range of 10~300µm , most suitable for the range of 20~200µm.

The refractive index of the light-transmitting substrate of the present invention is not particularly limited, for example, it is in the range of 1.30-1.80, preferably in the range of 1.40-1.70. In addition, physical treatments such as corona discharge treatment and plasma treatment, chemical treatments such as primer treatment, etc. Well-known and customary surface treatment such as treatment.

＜Resin layer＞ The resin layers (resin layers A and B) of the present invention are laminated on one side of the light-transmitting substrate of the present invention and impart excellent low moisture permeability to the optical film of the present invention. In addition, the resin layer of the present invention is also one that imparts excellent scratch resistance to the optical film of the present invention. Therefore, the optical film of the present invention having the resin layer of the present invention in a laminated structure can be suitably used as a polarizing plate protective film.

The resin layer of the present invention should be free from damage after using steel wool to carry out the scratch resistance test on its surface under the conditions of load 0.98N, moving speed 100mm/sec, and back and forth 10 times. That is, since the optical film of the present invention is coated with the resin layer of the present invention having excellent scratch resistance, even if it is thinned, it is not easy to be damaged in the production process, so when used as a polarizing plate protective film, it can provide polarized light with excellent durability. plate. The excellent scratch resistance of the resin layer of the present invention can be imparted by adjusting the composition, thickness, and the like described below for constituting the resin layer.

The resin layer of the present invention is formed of a cured product of a curable composition, and the curable composition includes a monomer selected from the group consisting of a monomer having a polymerizable functional group and an oligomer having a polymerizable functional group. at least one polymerizable compound. In this specification, the polymerizable compound constituting the resin layer of the present invention is sometimes referred to as "the polymerizable compound of the present invention", and the curable composition containing the polymerizable compound of the present invention is sometimes referred to as "the curable composition of the present invention". thing". The resin layer of the present invention is preferably composed of a cured product of the curable composition of the present invention containing the polymerizable compound of the present invention in that it can impart excellent low moisture permeability and scratch resistance to the optical film of the present invention. .

The "polymerizable functional group" of the polymerizable compound of the present invention is not particularly limited, and examples include unsaturated double bond groups, epoxy groups, oxetanyl groups, etc., which are characterized by excellent low moisture permeability and scratch resistance. From a viewpoint, it is preferably an unsaturated double bond group. Examples of the unsaturated double bond group include (meth)acryl, vinyl, styryl, and allyl, among which (meth)acryl is preferred. In addition, in this specification, "(meth)acryl" means either or both of "acryl" and "methacryl", and "(meth)acryl" also means "acrylic acid ” and “methacrylic acid” or both.

The number of "polymerizable functional groups" possessed by the polymerizable compound of the present invention is not particularly limited as long as it is one or more. From the viewpoint of imparting excellent low moisture permeability and scratch resistance to the optical film of the present invention, this The curable composition of the invention preferably contains at least 2 or more, preferably 3 or more, more preferably 4 or more, or 5 or more, 6 or more, 7 or more, 8 or more, 9 or more or A polymerizable compound having more than 10 polymerizable functional groups. The upper limit of the number of "polymerizable functional groups" is not particularly limited, and may be 30 or less, 25 or less, or 20 or less.

In order to impart excellent low moisture permeability to the optical film of the present invention, the curable composition of the present invention preferably contains a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule (hereinafter sometimes referred to as "polymerizable compound A") as the polymerizable compound of the present invention. We think that the cyclic aliphatic hydrocarbon group in the molecule of the polymerizable compound A will hydrophobize the resin layer of the present invention and reduce the moisture permeability. The curable composition of the present invention may contain one polymerizable compound A, or may contain two or more polymerizable compounds A.

The polymerizable functional groups of the polymerizable compound A are preferably unsaturated double bond groups such as (meth)acryl, vinyl, styryl, and allyl, among which (meth)acryl is more preferable. Particularly preferred are the following compounds containing two or more (meth)acryloyl groups in one molecule.

The number of "polymerizable functional groups" that the polymerizable compound A has in the molecule is not particularly limited as long as it is one or more. From the viewpoint of imparting excellent low moisture permeability and scratch resistance to the optical film of the present invention, It preferably has 2 or more, more preferably 3 or more, more preferably 4 or more polymerizable functional groups. The upper limit of the number of "polymerizable functional groups" that the polymerizable compound A has is not particularly limited, and may be 10 or less, 9 or less, or 8 or less.

The "cyclic aliphatic hydrocarbon group" of the polymerizable compound A in the molecule is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably a group derived from an alicyclic compound having 10 or more carbon atoms, and more preferably It is preferably a group derived from an alicyclic compound having 12 or more carbon atoms. The cyclic aliphatic hydrocarbon group is preferably a group derived from polycyclic compounds such as bicyclic and tricyclic.

Cyclic aliphatic hydrocarbon group (comprising linking group) should be the group shown in any one of following general formula (I)～(V), be preferably following general formula (I), (II) or (IV) The groups shown are more preferably groups represented by the following general formula (I). [chemical formula 1]

In the general formula (I), L and L' each independently represent a divalent or higher linking group. n represents an integer from 1 to 3. [chemical formula 2]

In the general formula (II), L and L' each independently represent a divalent or higher linking group. n represents an integer from 1 to 2. [chemical formula 3]

In the general formula (III), L and L' each independently represent a divalent or higher linking group. n represents an integer from 1 to 2. [chemical formula 4]

In the general formula (IV), L and L' each independently represent a linking group with a valence of more than two, and L" represents a hydrogen atom or a linking group with a valence of more than two. [Chemical formula 5]

In the general formula (V), L and L' each independently represent a divalent or higher linking group.

Specific examples of the cycloaliphatic hydrocarbon group include 1-3 valent groups derived from norsane, tricyclodecane, tetracyclododecane, pentacyclopentadecane, adamantane, bisamantane, and the like.

The polymerizable compound A comprising a group represented by any one of the above general formulas (I) to (V) as a cyclic aliphatic hydrocarbon group has a polymerizable function through the linking group represented by L, L' and L". Linking groups include: single bond, alkylene group that can be substituted with 1 to 6 carbons, amido group that can be disubstituted at N position, carbamoyl group that can be disubstituted at N position, ester group, oxygen A carbonyl group, an ether group, etc., and a group obtained by combining them.

The polymerizable compound A can be formed by, for example, a carboxyl group of a polyhydric alcohol such as a diol or a triol having the above-mentioned cyclic aliphatic hydrocarbon group and a compound having a (meth)acryl group, vinyl group, styryl group, or allyl group. It can be easily synthesized by one-stage or two-stage reaction of acids, carboxylic acid derivatives, epoxy derivatives, isocyanate derivatives, etc. By using (meth)acrylic acid, (meth)acryl chloride, (meth)acrylic anhydride, glycidyl (meth)acrylate, 1,1-bis(acryloxymethyl)ethyl base isocyanate, etc., and the polyol having the above-mentioned cycloaliphatic hydrocarbon group is reacted and synthesized.

[化學式7]

[化學式8]

[化學式9]

[化學式10]

[化學式11]

Although ideal specific examples of the polymerizable compound A are shown below, the present invention is not limited thereto. [chemical formula 6]

[chemical formula 7]

[chemical formula 8]

[chemical formula 9]

[chemical formula 10]

[chemical formula 11]

The content of the polymerizable compound A in the curable composition of the present invention is not particularly limited, but from the viewpoint of imparting excellent low moisture permeability to the resin layer of the present invention, it is 100% of the non-volatile solid content of the curable composition of the present invention. % by weight, preferably at least 10% by weight, more preferably at least 15% by weight, or at least 15% by weight, at least 20% by weight, at least 25% by weight, at least 30% by weight, at least 35% by weight, or at least 40% by weight More than, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or 90% by weight above. On the other hand, the resin layer of the present invention may be 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, from the viewpoint of achieving both low moisture permeability and scratch resistance at a higher level. % by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less % by weight or less, 20% by weight or less, 15% by weight or less, or 10% by weight or less.

In order to impart not only excellent low moisture permeability but also excellent scratch resistance to the optical film of the present invention, the curable composition of the present invention preferably further contains a polymerizable compound other than the polymerizable compound A, that is, a molecule A compound that does not have a cyclic aliphatic hydrocarbon group but has a polymerizable functional group (hereinafter sometimes referred to as "polymerizable compound B"). The crosslinking density of the polymerizable compound A tends to decrease due to the three-dimensional structure of the cyclic aliphatic hydrocarbon group in the molecule. We believe that the curable composition of the present invention contains the polymerizable compound B in addition to the polymerizable compound A, thereby increasing the crosslink density and improving the scratch resistance.

The polymerizable functional group of the polymerizable compound B is preferably an unsaturated double bond group such as (meth)acryl group, vinyl group, styryl group, and allyl group, among which a (meth)acryl group is more preferable. Particularly preferred are the following compounds containing two or more (meth)acryloyl groups in one molecule.

The number of "polymerizable functional groups" possessed by the polymerizable compound B is not particularly limited as long as it is 1 or more, but it is preferably 2 or more from the viewpoint that excellent scratch resistance can be imparted to the optical film of the present invention. , more preferably 3 or more, more preferably 4 or more, or 5 or more, 6 or more, 7 or more, 8 or more, 9 or more or 10 or more. The upper limit of the number of "polymerizable functional groups" that the polymerizable compound B has is not particularly limited, and may be 30 or less, 25 or less, or 20 or less.

The polymerizable compound B can be a monomer that does not have a cyclic aliphatic hydrocarbon group in its molecule but has a polymerizable functional group (hereinafter sometimes referred to as "polymerizable monomer B"), and a monomer that does not have a cyclic aliphatic hydrocarbon group in its molecule but has a polymerizable functional group. An oligomer of a sexual functional group (hereinafter sometimes referred to as "polymerizable oligomer B"). The curable composition of the present invention may contain only the polymerizable monomer B as the polymerizable compound B, may contain only the polymerizable oligomer B, or may contain both the polymerizable monomer B and the polymerizable oligomer B. From the viewpoint of forming a high crosslink density, it is preferable to include at least the polymerizable oligomer B.

Examples of the polymerizable monomer B include hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol Di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentylthritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra (Meth) acrylate, neopentylthritol tetra(meth)acrylate, neopentylthritol tri(meth)acrylate, dipenteoerythritol hexa(meth)acrylate, ginseng (2-hydroxyethyl) base) isocyanurate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, etc. The curable composition of the present invention may contain one kind of polymerizable monomer B, or may contain two or more kinds of polymerizable monomer B.

The polymerizable oligomer B is a compound containing two or more repeating units and having a polymerizable functional group. That is, the polymerizable oligomer B is a polymer having a polymerizable functional group in the molecule. Examples of the polymerizable oligomer B include urethane (meth)acrylate in which two or more (meth)acryl groups are added as functional groups to the urethane backbone, Polyester (meth)acrylate with two or more (meth)acryl groups added as functional groups, epoxy with two or more (meth)acryl groups added as functional groups to the epoxy skeleton (meth)acrylate, etc. From the viewpoint of forming a high crosslink density, it is preferable to contain at least urethane (meth)acrylate. The curable composition of the present invention may contain one kind of polymerizable oligomer B, or may contain two or more kinds of polymerizable oligomer B.

Urethane (meth)acrylate can be obtained by making a polyhydric alcohol, an isocyanate, and a hydroxy (meth)acrylate react, for example. As the polyol constituting the urethane (meth)acrylate, known polyols can be used without limitation, but from the viewpoint of increasing the crosslink density, it is preferable to have 3 or more hydroxyl groups (preferably 4 or more, More preferably 5 or more, more preferably 6 or more) of polyols, examples include trimethylolpropane, ethoxylated isocyanuric acid, neopentyl glycol, diperythritol, trineopentyl tetra Alcohol, Tetrapentylitol, etc. These polyhydric alcohols can be used individually or in mixture of 2 or more types.

As the isocyanate constituting the urethane (meth)acrylate, polyisocyanates composed of chain saturated hydrocarbons, cyclic saturated hydrocarbons, and aromatic hydrocarbons can be used. Examples of the polyisocyanate include chain saturated hydrocarbon isocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, Cyclic hydrocarbon isocyanates such as dicyclohexylmethane diisocyanate, methylene bis(4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated toluene diisocyanate, and 2,4-diisocyanate Cresyl ester, 1,3-stubble diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diisocyanate, 6-isopropyl-1,3-benzene Aromatic polyisocyanates such as diisocyanate and 1,5-naphthalene diisocyanate. Preferable specific examples include isophorone diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. These polyisocyanates can be used individually or in mixture of 2 or more types.

Hydroxyl (meth)acrylates constituting urethane (meth)acrylates include, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-(meth)acrylate -Hydroxybutyl ester, 6-hydroxyhexyl (meth)acrylate, etc. These hydroxy (meth)acrylates can be used individually or in mixture of 2 or more types.

Examples of urethane (meth)acrylate include ART RESIN UN series manufactured by Negami Industry Co., Ltd., NK oligo U series manufactured by Shin-Nakamura Chemical Co., Ltd., and ultraviolet UV series manufactured by Mitsubishi Chemical Co., Ltd.

Polyester (meth)acrylate can be obtained by reacting (meth)acrylic acid with the terminal hydroxyl group of the polyester which polymerized polyhydric alcohol and polycarboxylic acid, for example. Specific examples of polyester (meth)acrylate include ARONIX M-6000, ARONIX M-7000, ARONIX M-8000, and ARONIX M-9000 manufactured by Toagosei Co., Ltd.

Epoxy (meth)acrylate can be obtained by reacting (meth)acrylic acid with epoxy resin, for example. Specific examples of the epoxy (meth)acrylate include Ripoxy SP and Ripoxy VR manufactured by Showa Polymer Co., Ltd., and epoxy ester series manufactured by Kyoeisha Chemical Co., Ltd.

The weight average molecular weight of the polymerizable oligomer B is not particularly limited, but from the viewpoint of improving the scratch resistance of the resin layer of the present invention, it is preferably 400 or more, more preferably 500 or more, more preferably 600 or more, especially 700 or more. In addition, from the viewpoint of the coatability of the curable composition of the present invention, the weight average molecular weight of the polymerizable oligomer B is preferably 10,000 or less, more preferably 7,000 or less, more preferably 5,000 or less. The weight average molecular weight of the polymerizable oligomer B can be calculated|required using high performance liquid chromatography (HPLC), for example. For example, the HPLC8020 manufactured by Tosoh Co., Ltd. can be used as the device, and two TSKgelGMH-H (20) connected in series are used as columns, and tetrahydrofuran is used as a solvent, and the weight average molecular weight is measured at a flow rate of 0.5 mL/min. .

The content of the polymerizable compound B in the curable composition of the present invention is not particularly limited, but from the viewpoint of imparting excellent scratch resistance to the resin layer of the present invention, the content is 100% by weight relative to the non-volatile solid content of the curable composition of the present invention. %, preferably more than 5% by weight, more preferably more than 10% by weight, more preferably more than 15% by weight, or more than 20% by weight, more than 25% by weight, more than 30% by weight, more than 35% by weight, or more than 40% by weight % by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or 90% by weight % by weight or more. On the other hand, the resin layer of the present invention may be 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, or 70% by weight or less from the viewpoint of achieving both low moisture permeability and scratch resistance at a higher level. % by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less % by weight or less, 15% by weight or less, 10% by weight or less, or 5% by weight or less.

When the curable composition of the present invention contains polymerizable compound A and polymerizable compound B, from the viewpoint of imparting excellent low moisture permeability to the resin layer of the present invention, the ratio (polymerizable compound A/polymerizable compound B) is preferably More than 10/90, more preferably 15/85 or more, or 20/80 or more, 25/75 or more, 30/70 or more, 35/65 or more, 40/60 or more, 45/55 or more, 50/50 Above, above 55/45, above 60/40, above 65/35, above 70/30, above 75/25, above 80/20, above 85/15 or above 90/10. On the other hand, the resin layer of the present invention may be 95/5 or less, 90/10 or less, 85/15 or less, 80/20 or less, or 75 /25 or less, 70/30 or less, 65/35 or less, 60/40 or less, 55/45 or less, 50/50 or less, 45/55 or less, 40/60 or less, 35/65 or less, 30/70 or less, 25 Under /75, under 15/85, or under 10/90.

、2-氯9-氧硫𠮿

、2-甲基9-氧硫𠮿

、2,4-二甲基9-氧硫𠮿

、異丙基-9-氧硫𠮿

、2,4-二氯9-氧硫𠮿

、2,4-二乙基9-氧硫𠮿

、2,4-二異丙基9-氧硫𠮿

、十二基9-氧硫𠮿

等的9-氧硫𠮿

系化合物；樟腦醌；鹵化酮；醯基氧化膦；醯基膦酸酯等。該等聚合引發劑可單獨使用或可混合2種以上來使用。The curable composition of the present invention preferably contains a polymerization initiator, and the polymerization initiator is preferably a photopolymerization initiator. Examples of photopolymerization initiators include benzil, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxydiphenylketone, etc. Diphenyl ketone compounds; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl -Aromatic ketone compounds such as 2-hydroxypropiophenone and α-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-di Acetophenone series compounds such as ethoxyacetophenone and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropan-1-one; benzoin methyl Ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin methyl ether and other benzoin alkyl ether compounds; benzyl dimethyl ketal and other aromatic family of ketal compounds; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime systems such as 1-benzophenone-1,1-propanedione-2-(o-ethoxycarbonyl) oxime Compound; 9-oxosulfur 𠮿

, 2-Chloro9-oxosulfur 𠮿

, 2-methyl 9-oxosulfur 𠮿

, 2,4-Dimethyl 9-oxosulfur 𠮿

, Isopropyl-9-oxosulfur

, 2,4-dichloro-9-oxosulfur 𠮿

, 2,4-Diethyl 9-oxosulfur 𠮿

, 2,4-Diisopropyl 9-oxosulfur 𠮿

, Dodecyl 9-oxosulfur 𠮿

9-oxosulfur

series compounds; camphorquinone; halogenated ketones; acyl phosphine oxides; acyl phosphonates, etc. These polymerization initiators can be used individually or in mixture of 2 or more types.

The content of the photopolymerization initiator in the curable composition of the present invention is not particularly limited, but from the viewpoint of sufficiently obtaining low moisture permeability and scratch resistance of the resin layer of the present invention, the content of the photopolymerization initiator relative to the polymerizable compound (polymerizable compound A and polymerizable compound A and polymerizable compound A) is not particularly limited. The total of the active compounds B) 100 parts by weight, preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more. Also, from the viewpoint of suppressing the excessive absorption of radiation by the photopolymerization initiator, which prevents the curable composition of the present invention from sufficiently curing, 100 The content of the photopolymerization initiator in the curable composition of the present invention is preferably 10 parts by weight or less, more preferably 8 parts by weight or less.

Various leveling agents can be added to the curable composition of the present invention. As the above-mentioned leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used to prevent uneven coating (homogenize the coated surface). When antifouling property is required on the surface of the resin layer of the present invention, a leveling agent may also be blended appropriately. With respect to 100 parts by weight of the polymerizable compound (total of polymerizable compound A and polymerizable compound B), the blending amount of the aforementioned leveling agent is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight.

The curable composition of the present invention may contain a solvent. As the solvent, various solvents can be used in consideration of solubility of the polymerizable compound (polymerizable compound A and/or polymerizable compound B), drying property at the time of coating, and the like. Examples of the organic solvent include: dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxane, 1,3 ,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, diethyl ketone, Propyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, propionic acid Methyl ester, ethyl propionate, gamma-butyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate , 2-methoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetylacetate, acetylacetate Ethyl ester, methanol, ethanol, isopropanol, n-butanol, cyclohexanol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, ethyl Glycol ethyl ether, ethylene glycol isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol, hexane, heptane, octane, cyclohexane , methylcyclohexane, ethylcyclohexane, benzene, toluene, xylene, etc., can be used alone or in combination of two or more.

The curable composition of the present invention may further contain any appropriate additives such as plasticizers, surfactants, antioxidants, ultraviolet absorbers, thixotropic agents, antistatic agents, etc. as required, within the scope of not impairing the effects of the present invention.

The film thickness of the resin layer of the present invention is preferably 0.5-6 µm. As mentioned above, even if the aforementioned resin layer is thinned, excellent low moisture permeability can be imparted to the optical film of the present invention. When the optical film of the present invention is used as a polarizing plate protective film, the film thickness of the aforementioned resin layer is preferably 5.8 µm or less, more preferably 5.6 µm or less, from the viewpoint of making the polarizing plate thinner. From the standpoint of achieving both low moisture permeability and scratch resistance at a higher level, the lower limit of the film thickness of the aforementioned resin layer is preferably 1 µm or more, and may be 2 µm or more. The resin layer of the present invention may be one layer or a plurality of layers may be provided. When the resin layer of the present invention is composed of plural layers, the film thickness of the resin layer of the present invention is the total of the layers constituting the plural layers.

The resin layer of the present invention can be formed by mixing the polymeric compound (polymeric compound A and/or polymeric compound B) of the present invention with a photopolymerization initiator, a leveling agent, a solvent, and other additives as required Then, a coating liquid (the curable composition of the present invention) is prepared, and the coating liquid is applied to one side of the light-transmitting substrate and dried to harden the coating film.

The solid content concentration of the coating liquid is preferably 1% by weight to 70% by weight, more preferably 2% by weight to 50% by weight, more preferably 5% by weight to 40% by weight.

The coating method of the coating liquid includes, for example, dip coating, air knife coating, curtain coating, roll coating, wire bar coating, gravure coating, die coating, extrusion coating, rod coating, etc. Paint method, etc.

The curing of the coating film can be appropriately selected according to the type of curable composition and the like. When the curable composition is photocurable, it can be cured by irradiating light using a light source that emits light of a desired wavelength. As the light to be irradiated, for example, light with an exposure amount of 150 mJ/cm ² or more, preferably 200 mJ/cm ² to 1000 mJ/cm ² , can be used. In addition, heating may be performed during the photocuring treatment. Examples of light include ionizing radiation such as α-rays, β-rays, γ-rays, neutron rays, and electron beams, or ultraviolet rays, and ultraviolet rays are particularly preferred. In addition, the irradiation time, irradiation method, etc. are not particularly limited, as long as the photopolymerization initiator can be activated to initiate the reaction of the polymerizable compound.

＜Polarizer＞ The polarizing plate of the present invention has a laminated structure in which a polarizer is disposed on the opposite side of the optical film of the present invention to the resin layer. In FIG. 2 , the polarizing plate 20 has a laminated structure in which the polarizer 3 is arranged on the opposite side of the optical film 10 to the resin layer 1 . Since the optical film 10 is used as a protective film for the polarizer, the polarizer 20 has excellent low moisture permeability and scratch resistance even if the resin layer 1 is very thin, and quality deterioration such as fading of the polarizer 3 is unlikely to occur. In this embodiment, the second light-transmitting base material 4 and the adhesive layer 5 are further laminated sequentially on the opposite side of the optical film 10 of the polarizer 3 .

The polarizer 3 is an element that passes only light of a polarization plane in a fixed direction, and known ones can be used without limitation, for example, a polyvinyl alcohol-based polarizing film can be used. The polyvinyl alcohol-based polarizing film may be a polyvinyl alcohol-based film dyed with iodine, or may be a polyvinyl alcohol-based film dyed with a dichroic dye.

The polyvinyl alcohol-based polarizing film can be a film dyed with iodine or a dichroic dye after uniaxial stretching of the polyvinyl alcohol-based film (preferably a film that is further treated with a boron compound for durability); it can also be made of iodine or A polyvinyl alcohol-based film dyed with a dichroic dye and uniaxially stretched (preferably a film that is further treated with a boron compound for durability). The absorption axis of the polarizer is parallel to the extending direction of the film.

The thickness of the polarizer 3 is preferably 5 to 25 µm, and from the viewpoint of reducing the thickness of the polarizing plate 20, it is more preferably 10 to 15 µm.

The second light-transmitting substrate 4 is to protect the opposite side of the polarizer 3 from the optical film 10 (polarizer protective film), and can use the same glass or plastic film as the light-transmitting substrate of the present invention, preferably cellulose Resin, cyclic olefin polymer (COP), polycarbonate resin, more preferably cyclic olefin polymer (COP), polycarbonate resin. The light-transmitting substrate 4 may be made of the same material as that of the light-transmitting substrate 2, or may be made of a different material. The light-transmitting base material 4 may have the resin layer 1 laminated thereon, or may not have the resin layer 1 . In addition, the light-transmitting base material 4 may be composed of a single layer, or may have a laminated structure of two or more layers of the same or different layers.

In addition, the light-transmitting substrate 4 is also preferably an optical compensation film (retardation film) having an optical compensation layer including an optically anisotropic layer. Optical compensation films, for example, can improve the viewing angle characteristics of liquid crystal display screens. As the optical compensation film, known ones can be used without limitation, for example, retardation films described in JP-A-2014-194484 and the like can also be used.

The thickness of the light transmissive substrate 4 is preferably 5 to 25 µm, and from the viewpoint of reducing the thickness of the polarizing plate 20, it is more preferably 10 to 15 µm.

The adhesive layer 5 is formed by any appropriate adhesive. The material constituting the adhesive layer 5 can, for example, use the following polymers as the base polymer: acrylic polymers, polysiloxane polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine Polymers based on rubber, polymers based on rubber, polymers based on isocyanate, polymers based on polyvinyl alcohol, polymers based on gelatin, polymers based on vinyl, polymers based on latex, water-based polyesters, etc. Among them, from the viewpoint of low moisture permeability, acrylic polymers and/or rubber-based polymers are preferred as base polymers. The adhesive layer 5 may contain a single base polymer, or may contain two or more base polymers.

The thickness of the adhesive layer 5 is preferably 5 to 25 µm, and from the viewpoint of reducing the thickness of the polarizing plate 20, it is more preferably 10 to 20 µm.

The polarizer 20 can be obtained by laminating the polarizer 1 and the optical film 10 with an adhesive. In addition, the polarizer 1 and the light-transmitting base material 4 may be bonded together through an adhesive. The adhesive used for pasting can be a fully saponified polyvinyl alcohol aqueous solution (glue), or an active energy ray hardening adhesive.

The adhesive layer 5 can be formed by applying an adhesive composition including a base polymer constituting the adhesive to the light-transmitting substrate 4 , and drying and hardening as required. Alternatively, it can also be formed by forming the adhesive layer 5 on the separator in the same manner, and then attaching and transferring to the light-transmitting substrate 4 .

Layers other than the polarizing plate 20, the optical film 10, the polarizing plate 3, the light-transmitting substrate 4, and the adhesive layer 5 (such as a surface protection film, a separator, etc.) may be provided on the surface or between arbitrary layers. For example, the surface of the adhesive layer 5 can be protected by a separator, and the surface of the resin layer 1 of the optical film 10 can also be protected by a surface protection film.

The thickness of the polarizing plate 20 (total thickness including the light-transmitting substrate 4 and the adhesive layer 5) is preferably 50-100 µm, and from the viewpoint of thinning the polarizing plate 20, it is more preferably 60-75 µm.

＜Video Display Device＞ The image display device of the present invention has the polarizing plate of the present invention. The image display device of the present invention has the polarizing plate of the present invention in a laminated structure, so even if the resin layer 1 is very thin, it still has excellent low moisture permeability and scratch resistance, and quality deterioration such as fading of the polarizer 3 is less likely to occur. Therefore, even if the image display device of the present invention is thin, it is less likely to cause discoloration of the polarizing plate in a humid environment, and has excellent durability. In FIG. 3 , the image display device 30 has an image display panel 6 laminated on the adhesive layer 5 of the polarizing plate 20 . In this embodiment, the adhesive layer 7 and the optical member 8 are sequentially laminated on the resin layer 1 .

The video display panel 6 is not particularly limited, and examples thereof include a liquid crystal video display panel, a self-luminous video display panel (such as an organic EL (electroluminescence) video display panel, an LED video display panel), and the like.

The image display panel 6 is formed by arranging RGB elements alternately, and in order to improve the contrast, the spaces between the RGB elements should be filled with black matrix (BM).

The adhesive layer 7 can use a material containing the same base polymer as that exemplified in the adhesive layer 5 . Among them, from the viewpoint of low moisture permeability, acrylic polymers and/or rubber-based polymers are preferred as base polymers. The adhesive layer 7 may contain a single base polymer, or may contain two or more base polymers. The adhesive layer 7 can be made of the same material as the adhesive layer 5, or can be made of different materials.

The optical member 8 can use the same glass or plastic film as the light-transmitting substrate of the present invention, preferably acrylic resin, polyester resin, cyclic olefin polymer (COP), especially polyester resin. When the optical member 8 is positioned on the outermost surface on the viewing side of the image display device 30 , it functions as a covering member.

The image display device 30 may also include an optical film 10, a polarizing plate 3, a light-transmitting substrate 4, an adhesive layer 5, an image display panel 6, an adhesive layer 7, and an optical member other than the optical member 8 on the surface or between arbitrary layers. . The above-mentioned optical member is not particularly limited, and examples thereof include polarizing plates other than the polarizing plate 3 , retardation plates, antireflection films, viewing angle adjustment films, and optical compensation films. In addition, the above-mentioned optical member is also set to include a member (design film, decorative film, surface protection plate, etc.) that performs a decorative or protective function while maintaining the visibility of the image display device or input device.

The image display device 30 can be manufactured by laminating an optical film formed by laminating the image display panel 6, the polarizing plate 20, the optical member 8, and the adhesive layer 7, specifically, by applying heat and/or pressure to The equal build layers are implemented. These laminates may be cured by irradiating active energy rays after heating and/or pressurizing. Irradiation of active energy rays can be performed in the same manner as the formation of the resin layer of the present invention.

Example Hereinafter, the present invention will be described in more detail according to the examples, but the present invention is not limited by these examples.

Example 1 (Preparation of Coating Liquid for Resin Layer Formation) As the resin contained in the resin layer, 50 parts by weight (in terms of solid content) of ultraviolet curable acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-DCP", solid content 100%), ultraviolet curable Type acrylate resin (manufactured by Mitsubishi Chemical Co., trade name "UV-1700TL", solid content 80%) 50 parts by weight (in terms of solid content). For every 100 parts by weight of the resin solid content of the aforementioned resin, 5 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "OMNIRAD907"), a leveling agent (manufactured by Kyyoei Chemical Co., Ltd., trade name "LE- 303", solid content 40%) 0.2 parts by weight. This mixture was diluted with a mixed solvent of MIBK/cyclopentanone (60/40 by weight) so that the solid content concentration became 30%, and a coating liquid for forming a resin layer was prepared.

<Preparation of Optical Film> A transparent plastic film substrate (TAC, manufactured by FUJIFILM Co., Ltd., trade name "TJ25UL") was prepared as a light-transmitting substrate. Using a bar coater #7, the above-prepared coating solution for forming a resin layer was applied to one side of the above-mentioned transparent plastic film substrate to form a coating film. Then, the transparent plastic film substrate formed with the coating film is sent to the drying step. In the drying step, the aforementioned coating film was dried by heating at 60° C. for 1 minute. Afterwards, a high-pressure mercury lamp was used to irradiate ultraviolet rays with a cumulative light intensity of 220mJ/cm ² to harden the above-mentioned coating film to form a resin layer with a thickness of 2.5 µm, thereby obtaining the optical film 1 of Example 1. The details of the resin used in Example 1 are as follows.・A-DCP: Tricyclodecane dimethanol dimethacrylate ・UV-1700TL: 10-functional urethane acrylate

Example 2 The optical film 2 of Example 2 was obtained in the same manner as in Example 1 except that a coating film was formed using a bar coater #14.

Example 3 As the resin contained in the resin layer, 70 parts by weight (in terms of solid content) of A-DCP and 30 parts by weight (in terms of solid content) of UV-1700TL were blended, and the same method as in Example 1 was used except that Thus, the optical film 3 of Example 3 was obtained.

Example 4 As the resin contained in the resin layer, 70 parts by weight (in terms of solid content) of A-DCP and 30 parts by weight (in terms of solid content) of UV-1700TL were blended, and a coating film was formed using a bar coater #14. Besides, the optical film 4 of Example 4 was obtained in the same manner as in Example 1.

Example 5 The optical film 3 of Example 5 was obtained in the same manner as in Example 1, except that 0.1 parts by weight of the leveling agent contained in the resin layer was mixed and the cumulative light intensity was set at 260 mJ/cm ² .

Comparative example 1 As the resin contained in the resin layer, 40 parts by weight (in terms of solid content) and UV-1700TL of ultraviolet curable acrylic resin (manufactured by Toagosei Co., Ltd., trade name "M-920", solid content 100%) were prepared. 60 parts by weight (in terms of solid content), 3 parts by weight of OMNIRAD907, and 0.2 parts by weight of LE-303 were mixed. This mixture was diluted with MIBK/cyclopentanone mixed solvent (weight ratio 70/30) so that the solid content concentration became 30%, and the coating liquid for resin layer formation was prepared and blended. The optical film 6 of Comparative Example 1 was obtained in the same manner as in Example 1 except that the above-prepared coating solution for forming a resin layer was formed into a coating film using a bar coater #6.

Comparative example 2 As the resin contained in the resin layer, 40 parts by weight (in terms of solid content) and UV-1700TL of ultraviolet curable acrylic resin (manufactured by Toagosei Co., Ltd., trade name "M-920", solid content 100%) were prepared. 60 parts by weight (in terms of solid content), 3 parts by weight of OMNIRAD907, and 0.2 parts by weight of LE-303 were mixed. This mixture was diluted with MIBK/cyclopentanone mixed solvent (weight ratio 70/30) so that the solid content concentration became 30%, and the coating liquid for resin layer formation was prepared and blended. Optical film 7 of Comparative Example 2 was obtained in the same manner as in Example 1, except that the above-prepared coating solution for forming a resin layer was formed into a coating film using a bar coater #10.

(Evaluate) The following evaluations were performed using the optical films obtained in the above Examples and Comparative Examples. The evaluation method is shown below. List the results in Table 1.

(1) Film thickness measurement Using a digital linear gauge (trade name "MODEL D-10HS", manufactured by Ozaki Seisakusho Co., Ltd.), the film thickness of the optical films of the examples and comparative examples was measured against the width at 5 points, and the film thickness of the 5 points was The average value is taken as the total thickness. The film thicknesses of the light-transmitting substrates used in Examples and Comparative Examples were measured by the same measurement method, and the average value of the film thicknesses at 5 points was taken as the thickness of the substrate. The difference between the total thickness and the base material thickness was taken as the thickness of the resin layer.

(2) Determination of moisture permeability According to JIS Z0208, the moisture permeability at a temperature of 40° C. and a relative humidity of 92% was measured for the optical films of Examples and Comparative Examples. The temperature and humidity conditions for the test were set at 60°C and 90% relative humidity or at 65°C and 90% relative humidity, and measured in the same manner as the temperature and humidity conditions of 40°C and 92% for the examples and comparative examples. Moisture permeability of optical films.

(3) Evaluation of fading of polarizer After storing the optical films of Examples and Comparative Examples for 120 hours at a temperature of 60°C and a relative humidity of 90%, set the illumination of the backlight at 8000 candlepower in a dark room and observe the films. When there are no traces and other fading, it is judged that there is fading of the polarizer.

(4) Measurement of scratch resistance After cutting the optical films of Examples and Comparative Examples into a size of 5 cm x 15 cm, #0000 steel wool was brought into contact with the resin layer in such a way that the diameter was ^2.5 cm and the contact area was 6.25 x π cm. surface. A load of 100 gf (0.98 N) was applied to the aforementioned steel wool, and the surface of the aforementioned resin layer was rubbed back and forth 10 times at a moving speed of 100 mm/sec relative to the longitudinal direction of the film. Under the environment of fluorescent lamp and LED light source, visually judge whether there is any scratch in the central 5cm×5cm part of the film after the test.

[Table 1]

Modifications of the present invention are attached below. [Additional Note 1] An optical film comprising a resin layer layered on one surface of a light-transmitting substrate; the aforementioned resin layer is formed of a cured product of a curable composition, and the curable composition includes a polymer selected from At least one polymerizable compound in the group consisting of monomers with functional groups and oligomers with polymerizable functional groups; Subtract the moisture permeability M of the aforementioned optical film at a temperature of 40°C and a relative humidity of 92% from 1,000 ¹ [g/m ² ·24h] and dividing the obtained value by the thickness T[µm] of the aforementioned resin layer ((1,000-M ¹ )/T) is 100 or more. [Additional note 2] An optical film, which is a resin layer layered on one surface of a light-transmitting substrate; At least one polymerizable compound in the group consisting of monomers with functional groups and oligomers with polymerizable functional groups; Subtract the moisture permeability M of the aforementioned optical film at a temperature of 60°C and a relative humidity of 90% from 2,000 ² [g/m ² ·24h] and dividing the obtained value by the thickness T[µm] of the aforementioned resin layer ((2,000-M ² )/T) is 200 or more. [Additional Note 3] The optical film as in Note 1 or 2, wherein the product of the aforementioned value ((1,000-M ¹ )/T) as in Note 1 and the aforementioned value ((2,000-M ² )/T) as in Note 2[ ((1,000-M ¹ )/T)×((2,000-M ² )/T)] is 20,000 or more. [Appendix 4] The optical film according to any one of Appendices 1 to 3, which is subjected to a scratch resistance test using steel wool on the surface of the aforementioned resin layer under the conditions of a load of 0.98N, a moving speed of 100mm/sec, and 10 times of reciprocation. no damage. [Appendix 5] The optical film according to any one of Appendices 1 to 4, wherein the film thickness of the aforementioned resin layer is 0.5 to 6 µm. [Additional Note 6] The optical film according to any one of Additional Notes 1 to 5, wherein the aforementioned light-transmitting substrate comprises a compound selected from cellulose-based resins, polyester-based resins, acrylic resins, and cyclic olefin-based polymers. Consists of at least one of the groups. [Supplementary Note 7] A polarizing plate having a polarizer arranged on the side opposite to the aforementioned resin layer of the optical film according to any one of Supplementary Notes 1 to 6. [Additional Note 8] An image display device having the polarizing plate as in Additional Note 7. [Additional Note 9] The image display device according to Additional Note 8, wherein an adhesive layer and an optical member are sequentially laminated on the aforementioned resin layer.

10:Optical film 1: resin layer 2: Light-transmitting substrate 20: polarizer 3: Polarizer 4: Light-transmitting substrate (optical compensation film) 5: Adhesive layer 30: Image display device 6: Image display panel 7: Adhesive layer 8: Optical components

Fig. 1 is a schematic view (sectional view) showing an embodiment of the optical film of the present invention. FIG. 2 is a schematic view (sectional view) showing an embodiment of a polarizing plate having the optical film of FIG. 1 . FIG. 3 is a schematic view (sectional view) showing an embodiment of an image display device having the polarizing plate shown in FIG. 2 .

10:Optical film

1: resin layer

2: Light-transmitting substrate

Claims (9)

An optical film, which has a resin layer layered on one surface of a light-transmitting substrate; the aforementioned resin layer is formed of a cured product of a curable composition, and the curable composition is selected from the group consisting of monomers having polymerizable functional groups. At least one polymeric compound in the group consisting of a polymeric body and an oligomer with a polymeric functional group; Subtract the moisture permeability M ¹ of the aforementioned optical film at a temperature of 40°C and a relative humidity of 92% from 1,000 [g/ m ² ·24h] and dividing the obtained value by the thickness T[µm] of the aforementioned resin layer ((1,000-M ¹ )/T) is 100 or more. An optical film, which has a resin layer layered on one surface of a light-transmitting substrate; the aforementioned resin layer is formed of a cured product of a curable composition, and the curable composition is selected from the group consisting of monomers having polymerizable functional groups. At least one polymeric compound in the group consisting of a polymeric body and an oligomer with a polymeric functional group; Subtract the moisture permeability M ² of the aforementioned optical film at a temperature of 60°C and a relative humidity of 90% from 2,000 [g/ m ² ·24h] and dividing the obtained value by the thickness T[µm] of the aforementioned resin layer ((2,000-M ² )/T) is 200 or more. The optical film according to claim 1 or 2, wherein the product of the aforementioned value ((1,000-M ¹ )/T) of claim 1 and the aforementioned value ((2,000-M ² )/T) of claim 2 [( (1,000-M ¹ )/T)×((2,000-M ² )/T)] is 20,000 or more. The optical film according to any one of Claims 1 to 3, which has no damage after the scratch resistance test is carried out on the surface of the aforementioned resin layer using steel wool under the conditions of a load of 0.98N, a moving speed of 100mm/sec, and 10 times of reciprocation. The optical film according to any one of claims 1 to 4, wherein the film thickness of the aforementioned resin layer is 0.5-6 µm. The optical film according to any one of claims 1 to 5, wherein the light-transmitting substrate is selected from the group consisting of cellulose-based resins, polyester-based resins, acrylic resins, and cyclic olefin-based polymers At least 1 of them. A polarizing plate having a polarizer arranged on the side opposite to the resin layer of the optical film according to any one of claims 1 to 6. An image display device having the polarizing plate according to Claim 7. According to the image display device of claim 8, an adhesive layer and an optical member are sequentially laminated on the aforementioned resin layer.

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