JP2022149456A - optical film - Google Patents

Abstract

To provide an optical film which excels in both low moisture permeability and in excoriation resistance and is suitable for polarizing plate projective films.SOLUTION: This optical film 10 has a laminate structure with a resin layer 1 laminated on one surface of a light permeable substrate 2. The resin layer 1 is formed from a cured substance of a curable composition that contains a polymerizable compound A having a cyclic aliphatic hydrocarbon and an unsaturated double bond group and a curable composition that contains a multifunctional polymerizable compound B other than the polymerizable compound A. The ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A/polymerizable compound B) is 95/5 to 10/90.SELECTED DRAWING: Figure 1

Description

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

Due to the image forming method of an image display device (for example, a liquid crystal display device, an organic EL display device, etc.), in many cases, a polarizing plate is arranged on at least one side of a display cell. The polarizing plate plays a role of passing only light with a plane of polarization in a certain direction, and the performance of the image display device is greatly influenced by the performance of the polarizing plate. A polarizing plate generally has a structure in which a polarizer made of a polyvinyl alcohol film or the like to which iodine or a dye is adsorbed and oriented and a transparent protective film (polarizing plate protective film) are attached to at least one surface of the polarizer. (For example, Patent Document 1).

JP-A-2000-338329

In recent years, the market for mobile applications such as smartphones and tablet terminals has expanded, and the need for thinner image display devices has increased further. . However, there is a problem that as the thickness of the polarizing plate protective film becomes thinner, the protective function for the polarizer deteriorates.

For example, when the polarizing plate protective film becomes thinner, the permeability to moisture (moisture permeability) increases, and the polarizing performance of the polarizer disappears in a humidified environment, which may cause a so-called "color loss" phenomenon.

Further, when the thickness of the polarizing plate protective film is reduced, the surface hardness and scratch resistance are lowered, the film is easily scratched during the manufacturing process, and the performance of the polarizing plate is deteriorated, such as low moisture permeability. Therefore, the optical film used for the polarizing plate protective film is also required to have excellent scratch resistance.

In order to increase the low moisture permeability of the polarizing plate protective film, it is necessary to introduce a highly hydrophobic structure as the resin constituting the film, but the highly hydrophobic chemical structure is generally bulky, resulting in a loose structure. There is a problem that the surface hardness and scratch resistance tend to decrease, that is, low moisture permeability and scratch resistance are in a trade-off relationship, and it is generally difficult to achieve both.

The present invention was conceived under the circumstances as described above, and an object of the present invention is to provide a polarizing plate protective film that can achieve both excellent low moisture permeability and scratch resistance even if it is thin. It is to provide a suitable optical film.

A first aspect of the present invention provides an optical film in which a resin layer is laminated on one surface of a light-transmitting substrate. The resin layer imparts excellent low moisture permeability to the optical film of the first aspect of the present invention. The resin layer also imparts excellent scratch resistance to the optical film of the first aspect of the present invention. Therefore, the optical film according to the first aspect of the present invention, which has the resin layer in a laminated structure, is suitable as a polarizing plate protective film.

In the optical film of the first aspect of the present invention, the resin layer comprises a polymerizable compound A having a cycloaliphatic hydrocarbon group and an unsaturated double bond group, and a polymerizable compound B other than the polymerizable compound A. It is formed of a cured product of a curable composition containing. This configuration is suitable for imparting excellent low moisture permeability to the optical film of the first aspect of the present invention. It is also suitable for imparting excellent scratch resistance to the optical film of the first aspect of the present invention.

In the optical film of the first aspect of the present invention, the ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A/polymerizable compound B) is 95/5 to 10/90. The cycloaliphatic hydrocarbon group of the polymerizable compound A has a highly hydrophobic chemical structure, and can impart excellent low moisture permeability to the resin layer. and scratch resistance tend to decrease. On the other hand, the polymerizable compound B is polyfunctional, and by increasing the crosslink density, it is possible to increase the scratch resistance of the resin layer. Therefore, it contains the polymerizable compound A and the polymerizable compound B, and the ratio (polymerizable compound A/polymerizable compound B) is formed from a cured product of a curable composition having a ratio of 95/5 to 10/90 The optical film according to the first aspect of the present invention, which includes the resin layer in a laminated structure, can achieve both excellent low moisture permeability and scratch resistance.

The ratio of the polymerizable compound A and the polymerizable compound B (polymerizable compound A/polymerizable compound B) is preferably 10/90 or more from the viewpoint of imparting excellent low moisture permeability to the resin layer. /85 or more is more preferable, 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 or more, 55/45 or more, 60 /40 or greater, 65/35 or greater, 70/30 or greater, 75/25 or greater, 80/20 or greater, 85/15 or greater, or 90/10 or greater. On the other hand, from the viewpoint that the resin layer achieves both low moisture permeability and scratch resistance at a higher level, and from the viewpoint of preventing the occurrence of "color loss" of the polarizer by appropriately releasing moisture in the polarizing plate to the outside. , 95/5 or less, 90/10 or less, 85/15 or less, 80/20 or less, 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, 25/75 or less, 15/85 or less, or 10/90 or less.

In the optical film of the first aspect of the present invention, the polymerizable compound B is preferably a 5- to 10-functional urethane (meth)acrylate. This configuration is preferable for increasing the crosslink density of the resin layer and improving the scratch resistance.

In the optical film according to the first aspect of the present invention, the film thickness of the resin layer is preferably 0.5 to 5 μm. As described above, even if the resin layer is thin, it is possible to impart excellent low moisture permeability and scratch resistance to the optical film of the first aspect of the present invention. When the optical film of the first aspect of the present invention is used as a polarizing plate protective film, the film thickness of the resin layer is preferably 4.5 μm or less, more preferably 4 μm or less, from the viewpoint that the polarizing plate can be made thinner. Preferably, it may be 3.2 μm or less, or 3 μm or less. The lower limit of the film thickness of the resin layer is preferably 1.0 μm or more, more preferably 1.8 μm or more, and 2 μm or more from the viewpoint of achieving both low moisture permeability and scratch resistance at a higher level. good too.

In the optical film of the first aspect of the present invention, the light-transmissive substrate may contain at least one selected from the group consisting of cellulose resins, polyester resins, acrylic resins, and cyclic olefin polymers. preferable. These resins can be suitably used as base materials for polarizing plate protective films.

A second aspect of the present invention provides a polarizing plate in which a polarizer is arranged on the side of the optical film of the first aspect of the present invention opposite to the resin layer.
Furthermore, a third aspect of the present invention provides an image display device having the polarizing plate of the second aspect of the present invention. In the image display device according to the third aspect of the present invention, it is preferable that an adhesive layer and an optical member are laminated in this order on the resin layer.

The polarizing plate of the second aspect of the present invention uses the optical film of the first aspect of the present invention as a polarizing plate protective film, so that even if the resin layer is thin, it has excellent low moisture permeability and scratch resistance. have Therefore, even if the image display device of the third aspect of the present invention having the polarizing plate of the second aspect of the present invention is thin, the polarizing plate is less likely to lose color in a humidified environment, and the display device is durable. Excellent for

The polarizing plate obtained by using the optical film of the present invention as a polarizing plate protective film has both excellent low moisture permeability and scratch resistance even if it is thin. Excellent.

FIG. 1 is a schematic diagram (cross-sectional view) showing one embodiment of the optical film of the present invention. FIG. 2 is a schematic diagram (cross-sectional view) showing an embodiment of a polarizing plate having the optical film of FIG. FIG. 3 is a schematic diagram (cross-sectional view) showing an embodiment of an image display device having the polarizing plate of FIG.

A first aspect of the present invention provides an optical film in which a resin layer is laminated on one surface of a light transmissive substrate.
The optical film of the first aspect of the present invention may be referred to herein as "the optical film of the present invention". In addition, the light-transmitting substrate and the resin layer constituting the optical film of the present invention may be referred to herein as "the light-transmitting substrate of the present invention" and "the resin layer of the present invention", respectively. be. Also, the term "film" includes the meanings of "sheet" and "tape". That is, the optical film of the present invention may be in the form of a sheet or tape.

A second aspect of the present invention provides a polarizing plate in which a polarizer is arranged on the side of the optical film of the present invention opposite to the resin layer. In this specification, the polarizing plate of the second aspect of the present invention may be referred to as "the polarizing plate of the present invention".
Moreover, the 3rd side surface of this invention provides the image display apparatus which has a polarizing plate of this invention. The image display device according to the third aspect of the present invention may be referred to as "the image display device of the present invention" in this specification.

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 (cross-sectional view) showing one 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 laminated on one surface of a light transmissive substrate 2 .

FIG. 2 is a schematic diagram (cross-sectional view) showing one embodiment of the polarizing plate of the present invention.
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 from the resin layer 1 . In this embodiment, on the opposite side of the polarizer 3 from the optical film 10, a second light-transmitting substrate 4 and an adhesive layer 5 are further laminated in this order.

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

<Optical film>
The term “optical” in the optical film of the present invention means that it is used for optical purposes, and more specifically means that it is used for manufacturing products (optical products) using optical members. Examples of optical products include image display devices, input devices such as touch panels, and liquid crystal image display devices, self-luminous image display devices (eg, organic EL (electroluminescence) image display devices, LED image display devices, etc.). ) and the like. More specifically, it can be suitably used as a protective film for a polarizing plate that constitutes an image display device.

The form of the optical film of the present invention is not particularly limited as long as the resin layer is laminated on one side 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. 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 both resin layers are provided by the resin layer of the present invention. A layer may be provided by the resin layer of the present invention, and the other resin layer may be provided by a resin layer other than the resin layer of the present invention (another resin layer). 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 only on one side.

The optical film of the present invention may include, in addition to the light-transmitting substrate of the present invention and the resin layer of the present invention, other layers, for example, other than the light-transmitting substrate of the present invention, as long as the effects of the present invention are not impaired. , a resin layer other than the resin layer of the present invention, an intermediate layer, an undercoat layer, an antistatic layer, a separator, a surface protective film, etc. on the surface or between any layers.

The moisture permeability M ¹ [g/m ² ·24h] of the optical film of the present invention in an environment of a temperature of 40°C and a relative humidity of 92% is preferably 700 g/m ² ·24h or less. The configuration in which the moisture permeability M ¹ is 700 g/m ² ·24 h or less can suppress the occurrence of "color loss" of the polarizer in a humidified environment when the optical film of the present invention is used as a polarizing plate protective film. point is preferable. From the viewpoint of suppressing the color loss of the polarizer at a higher level, the moisture permeability M ¹ is preferably 600 g/m ² ·24h or less, and may be 550 g/m ² ·24h or less. Although the lower limit of the moisture permeability M ¹ is not particularly limited, it is preferably 100 g/m ² ·24 h or more from the viewpoint of preventing the occurrence of "color loss" of the polarizer by allowing the moisture in the polarizing plate to escape to the outside. 200 g/m ² ·24h or more is more preferable, and it may be 300 g/m ² ·24h or more, 310 g/m ² ·24h or more, or 320 g/m ² ·24h or more.

The moisture permeability M ² [g/m ² ·24h] of the optical film of the present invention in an environment of a temperature of 60°C and a relative humidity of 90% is preferably 1,500 g/m ² ·24h or less. The configuration in which the moisture permeability M ² is 1,500 g/m ² ·24 h or less prevents the occurrence of “color loss” in the polarizer in a humidified environment when the optical film of the present invention is used as a polarizing plate protective film. This is preferable in that it can be suppressed. From the viewpoint of suppressing the occurrence of color loss of the polarizer at a higher level, the moisture permeability M ² is preferably 1,400 g/m ² ·24 h or less, more preferably 1,300 g/m ² ·24 h or less. , 200 g/m ² ·24 h or less. Although the lower limit of the moisture permeability M ² is not particularly limited, it is preferably 300 g/m ² ·24 h or more from the viewpoint of preventing the occurrence of "color loss" of the polarizer by allowing the moisture in the polarizing plate to escape to the outside. It is more preferably 500 g/m ² ·24h or more, and may be 800 g/m ² ·24h or more.

The moisture permeability M ³ [g/m ² ·24h] of the optical film of the present invention in an environment of a temperature of 65°C and a relative humidity of 90% is preferably 2,000 g/m ² ·24h or less. The configuration in which the moisture permeability M ³ is 2,000 g/m ² ·24 h or less prevents the occurrence of “color loss” in the polarizer in a humidified environment when the optical film of the present invention is used as a polarizing plate protective film. This is preferable in that it can be suppressed. From the viewpoint of suppressing the occurrence of color loss of the polarizer at a higher level, the moisture permeability M ³ is preferably 1,800 g/m ² ·24 h or less, more preferably 1,600 g/m ² ·24 h or less. , 400 g/m ² ·24 h or less. The lower limit of the moisture permeability M ³ is not particularly limited, but is preferably 500 g/m ² ·24 h or more from the viewpoint of preventing the occurrence of "color loss" of the polarizer by allowing the moisture in the polarizing plate to escape to the outside. It is more preferably 750 g/m ² ·24h or more, and may be 1,000 g/m ² ·24h or more.

In the optical film of the present invention, the thickness T [μm] of the resin layer of the present invention and the moisture permeability M ¹ [g/m ² ·24 h of the optical film of the present invention in an environment of a temperature of 40° C. and a relative humidity of 92%. ] (T×M ¹ ) is preferably 1,500 or less. The resin layer of the present invention imparts excellent low moisture permeability to the optical film of the present invention. In general, the thicker the film, the higher the moisture permeability, and the thinner the film, the lower the moisture permeability. Yes, in an inversely proportional relationship. Therefore, the product of the thickness T [μm] of the resin layer of the present invention and the moisture permeability M ¹ (T×M ¹ ) can be an index of the moisture permeability of the resin layer itself of the present invention. It can be said that it is excellent in low moisture permeability. Therefore, the optical film of the present invention having a laminate structure of the resin layer of the present invention having the product (T×M ¹ ) of 1,500 or less exhibits excellent low moisture permeability even when the resin layer of the present invention is thin. It has both thinness and excellent low moisture permeability.

The structure in which the product (T×M ¹ ) is 1,500 or less provides an excellent low-power film even when the resin layer of the present invention is thin when the optical film of the present invention is used as a polarizing plate protective film. It is preferable in that moisture permeability can be imparted and the occurrence of "color loss" of the polarizer can be suppressed in a humidified environment. From the viewpoint of achieving both suppression of color loss of the polarizer and thinning of the resin layer of the present invention at a higher level, the product (T×M ¹ ) is preferably 1,400 or less, more preferably 1,300 or less. More preferably, it may be 1,200 or less. The lower limit of the product (T×M ¹ ) is not particularly limited, but is preferably 500 or more, more preferably 600 or more, from the viewpoint of preventing the occurrence of "color dropout" of the polarizer by allowing moisture in the polarizing plate to escape to the outside. is more preferable, and may be 700 or more.

In the optical film of the present invention, the thickness T [μm] of the resin layer of the present invention and the moisture permeability M ² [g/m ² ·24 h] of the optical film of the present invention in an environment of a temperature of 60° C. and a relative humidity of 90%. (T×M ² ) is preferably 3,000 or less. Like the product (T×M ¹ ), the product (T×M ² ) can also be an index of the moisture permeability of the resin layer of the present invention, and it can be said that the lower the product, the better the low moisture permeability. Therefore, the optical film of the present invention having a laminate structure of the resin layer of the present invention having the product (T×M ² ) of 3,000 or less exhibits excellent low moisture permeability even when the resin layer of the present invention is thin. It is preferable because it has both thinness and excellent low moisture permeability.

The configuration in which the product (T×M ² ) is 3,000 or less is such that when the optical film of the present invention is used as a polarizing plate protective film, even if the resin layer of the present invention is thin, It is preferable in that the occurrence of "color loss" of the polarizer can be suppressed in . From the viewpoint of achieving both suppression of color loss of the polarizer and thinning of the resin layer of the present invention at a higher level, the product (T×M ² ) is preferably 2,900 or less, more preferably 2,800 or less. More preferably, it may be 2,700 or less. The lower limit of the product (T×M ² ) is not particularly limited, but is preferably 500 or more from the viewpoint of preventing the occurrence of "color dropout" of the polarizer by allowing moisture in the polarizing plate to escape to the outside. 000 or more is more preferable, and 1,500 or more may be sufficient.

In the optical film of the present invention, the product ((T×M ^{1 )×(T×M 2 )) of the product (T×M 1 ) and the product (T×M 2 ) is} 4,500,000 or less. is preferably The product ((T×M ¹ )×(T×M ² )), like the product (T×M ¹ ) and the product (T×M ² ), has the moisture permeability of the resin layer itself of the present invention. It can be said that the lower the moisture permeability, the better the low moisture permeability. Therefore, the optical film of the present invention having a laminated structure comprising the resin layer of the present invention in which the product ((T×M ¹ )×(T×M ² )) is 4,500,000 or less is the resin layer of the present invention. Excellent low moisture permeability is imparted even when the thickness is reduced, and both thinness and excellent low moisture permeability are achieved, which is preferable.

The structure in which the product ((T×M ¹ )×(T×M ² )) is 4,500,000 or less is such that when the optical film of the present invention is used as a polarizing plate protective film, the resin of the present invention Even if the layer is thin, it is preferable in that it can suppress the occurrence of "color loss" of the polarizer in a humidified environment. From the viewpoint of achieving a higher level of both the suppression of color loss in the polarizer and the thinning of the resin layer of the present invention, the product ((T×M ¹ )×(T×M ² )) is 4,000. ,000 or less, and more preferably 3,500,000 or less. Although the lower limit of the product ((T×M ¹ )×(T×M ² )) is not particularly limited, it prevents the occurrence of “color loss” in the polarizer by allowing moisture in the polarizing plate to escape to the outside. Therefore, it is preferably 50,000 or more, more preferably 100,000 or more, and may be 150,000 or more.

In the optical film of the present invention, the thickness T [μm] of the resin layer of the present invention and the moisture permeability M ³ [g/m ² ·24 h] of the optical film of the present invention under an environment of a temperature of 65°C and a relative humidity of 90%. (T×M ³ ) is preferably 4,000 or less. The product (T×M ³ ), like the product (T×M ¹ ) and the product (T×M ² ), can be an indicator of the moisture permeability of the resin layer itself of the present invention. It can be said that it has excellent moisture permeability. Therefore, the optical film of the present invention having a laminate structure of the resin layer of the present invention having the product (T×M ³ ) of 4,000 or less exhibits excellent low moisture permeability even when the resin layer of the present invention is thin. It is preferable because it has both thinness and excellent low moisture permeability.

The structure in which the product (T×M ³ ) is 4,000 or less is such that when the optical film of the present invention is used as a polarizing plate protective film, even if the resin layer of the present invention is thin, It is preferable in that the occurrence of "color loss" of the polarizer can be suppressed in . From the viewpoint of achieving both suppression of color loss of the polarizer and thinning of the resin layer of the present invention at a higher level, the above product (T×M ³ ) is preferably 3,800 or less, more preferably 3,600 or less. More preferably, it may be 3,400 or less. The lower limit of the product (T×M ³ ) is not particularly limited, but is preferably 1,000 or more from the viewpoint of preventing the occurrence of "color loss" of the polarizer by releasing the moisture in the polarizing plate to the outside. It is more preferably 1,500 or more, and may be 2,000 or more.

In the optical film of the present invention, the value obtained by subtracting the moisture permeability M ¹ [g/m ² ·24 h] of the optical film under an environment of a temperature of 40°C and a relative humidity of 92% from 1,000 is The value ((1,000-M ¹ )/T) divided by the thickness T [μm] is preferably 100 or more. The resin layer of the present invention imparts excellent low moisture permeability to the optical film of the present invention. In general, the thicker the film, the higher the moisture permeability, and the thinner the film, the lower the moisture permeability. be. The above numerical value "1,000" is an approximate value of the moisture permeability of the light-transmitting substrate itself (light-transmitting substrate without resin layer) of the present invention under an environment of a temperature of 40°C and a relative humidity of 92%. , and the value obtained by subtracting the moisture permeability M ¹ [g/m ² ·24 h] from 1,000 is an approximate value of the moisture permeability decreased by providing the resin layer on the light-transmitting substrate of the present invention. . Therefore, the above value ((1,000-M ¹ )/T) can be used as an indicator of moisture permeability to be lowered in an environment of 40° C. temperature and 92% relative humidity per 1 μm thickness of the resin layer of the present invention. , and it can be said that the higher the value, the better the low moisture permeability. Therefore, an optical film having a laminated structure of the resin layer of the present invention in which the value ((1,000−M ¹ )/T) is 100 or more is imparted with excellent low moisture permeability even if the resin layer is thin. , which has both thinness and excellent low moisture permeability.

The value ((1,000−M ¹ )/T) of 100 or more is a case where the resin layer of the present invention is thin when the optical film of the present invention is used as a polarizing plate protective film. It is preferable in that it can impart excellent low moisture permeability and can suppress the occurrence of "color loss" of the polarizer in a humidified environment. From the viewpoint of achieving both suppression of color loss of the polarizer and thinning of the resin layer of the present invention at a higher level, the value ((1,000−M ¹ )/T) is preferably 105 or more, and 110 More preferably, it may be 115 or more. The upper limit of the value ((1,000−M ¹ )/T)) is not particularly limited, but from the viewpoint of preventing the occurrence of “color loss” of the polarizer by allowing moisture in the polarizing plate to escape to the outside, It is preferably 500 or less, more preferably 400 or less, and may be 300 or less.

In the optical film of the present invention, the value obtained by subtracting the moisture permeability M ² [g/m ² ·24 h] of the optical film under an environment of a temperature of 60°C and a relative humidity of 90% from 2,000 is The value ((2,000−M ² )/T) divided by the thickness T [μm] is preferably 200 or more. The above numerical value "2,000" is an approximate value of the moisture permeability of the light-transmitting substrate itself of the present invention (light-transmitting substrate without a resin layer) under an environment of a temperature of 60°C and a relative humidity of 90%. and the value obtained by subtracting the moisture permeability M ² [g/m ² ·24 h] from 2,000 is the approximate value of the moisture permeability that is lowered by providing the resin layer on the light-transmitting substrate of the present invention. . Therefore, the above value ((2,000-M ² )/T) can be used as an indicator of moisture permeability to be lowered in an environment of 60° C. temperature and 90% relative humidity per 1 μm thickness of the resin layer of the present invention. , and it can be said that the higher the value, the better the low moisture permeability. Therefore, an optical film having a laminated structure of the resin layer of the present invention in which the value ((2,000-M ² )/T) is 200 or more is imparted with excellent low moisture permeability even when the resin layer is thin. , which has both thinness and excellent low moisture permeability.

The value ((2,000−M ² )/T) of 200 or more is a case where the resin layer of the present invention is thin when the optical film of the present invention is used as a polarizing plate protective film. It is preferable in that it can impart excellent low moisture permeability and can suppress the occurrence of "color loss" of the polarizer in a humidified environment. From the viewpoint of achieving a higher level of both suppression of color loss of the polarizer and thinning of the resin layer of the present invention, the product value ((2,000−M ² )/T) is preferably 210 or more. 220 or more is more preferable, and 230 or more may be sufficient. The upper limit of the value ((2,000−M ² )/T)) is not particularly limited, but from the viewpoint of preventing the occurrence of “color loss” of the polarizer by allowing moisture in the polarizing plate to escape to the outside, It is preferably 1,000 or less, more preferably 800 or less, and may be 500 or less.

In the optical film of the present invention, the product of the value ((1,000-M ¹ )/T) and the value ((2,000-M ² )/T) [((1,000-M ¹ ) /T)×((2,000−M ² )/T)] is preferably 20,000 or more. The product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is also the value ((1,000-M ¹ )/T), the value (( Similar to 2,000-M ² )/T), it can be an index of the moisture permeability of the resin layer itself of the present invention, and it can be said that the higher the ratio, the better the low moisture permeability. Therefore, the product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] of the present invention having a laminate structure of the resin layer of the present invention in which the product [((1,000-M 1 )/T)] is 20,000 or more The optical film of (1) is preferable because excellent low moisture permeability is imparted even when the resin layer of the present invention is thin, and both thinness and excellent low moisture permeability can be achieved.

The structure in which the product [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is 20,000 or more makes the optical film of the present invention a polarizing plate protective film. , even if the resin layer of the present invention is thin, it is possible to suppress the occurrence of "color loss" of the polarizer in a humidified environment. From the viewpoint of achieving a higher level of both the suppression of the occurrence of color loss in the polarizer and the thinning of the resin layer of the present invention, the product [((1,000-M ¹ )/T) × ((2,000- M ² )/T)] is preferably 21,000 or more, more preferably 22,000 or more. The upper limit of [((1,000-M ¹ )/T)×((2,000-M ² )/T)] is not particularly limited, but the 200,000 or less is preferable, 150,000 or less is more preferable, and 120,000 or less may be sufficient from a viewpoint of preventing generation|occurrence|production of "color omission".

In the optical film of the present invention, the value obtained by subtracting the moisture permeability M ³ [g/m ² ·24 h] of the optical film under an environment of 65°C and 90% relative humidity from 2,700 is The value ((2,700-M ³ )/T) divided by the thickness T [μm] is preferably 250 or more. The above numerical value "2,700" is an approximate value of the moisture permeability of the light-transmitting substrate itself of the present invention (light-transmitting substrate without a resin layer) under an environment of a temperature of 65°C and a relative humidity of 90%. , and the value obtained by subtracting the moisture permeability M ³ [g/m ² ·24 h] from 2,700 is an approximate value of the moisture permeability decreased by providing the resin layer on the light-transmitting substrate of the present invention. . Therefore, the value ((2,700-M ³ )/T) can be used as an indicator of moisture permeability to be lowered in an environment of 65° C. temperature and 90% relative humidity per 1 μm thickness of the resin layer of the present invention. , and it can be said that the higher the value, the better the low moisture permeability. Therefore, the optical film having the resin layer of the present invention in which the value ((2,700−M ³ )/T) is 250 or more in a laminated structure is imparted with excellent low moisture permeability even if the resin layer is thin. , which has both thinness and excellent low moisture permeability.

The value ((2,700−M ³ )/T) of 250 or more is a case where the resin layer of the present invention is thin when the optical film of the present invention is used as a polarizing plate protective film. It is preferable in that it can impart excellent low moisture permeability and can suppress the occurrence of "color loss" of the polarizer in a humidified environment. From the viewpoint of achieving both suppression of color loss of the polarizer and thinning of the resin layer of the present invention at a higher level, the value ((2,700−M ³ )/T) is preferably 270 or more, and 280 More preferably, it may be 300 or more. The upper limit of the value ((2,700−M ³ )/T)) is not particularly limited, but from the viewpoint of preventing the occurrence of “color loss” of the polarizer by allowing the moisture in the polarizing plate to escape to the outside, It is preferably 1,000 or less, more preferably 800 or less, and may be 600 or less.

The optical film of the present invention has a change of 20 or less in moisture permeability [g/m ² ·24 h] of the optical film in an environment of 40°C temperature and 92% relative humidity before and after the following scratch resistance test. is preferably
Scratch resistance test The surface of the resin layer is reciprocated 10 times with steel wool under the conditions of a load of 3.92 N and a moving speed of 100 mm/sec.
In general, the moisture permeability after the abrasion resistance test tends to be higher than the moisture permeability before the test, but the change when the moisture permeability after the abrasion resistance test is lower than the moisture permeability before the test It shall also include quantity. Therefore, the amount of change is, for example, the absolute value of the value obtained by subtracting the moisture permeability before the test from the moisture permeability after the scratch resistance test.

The resin layer of the present invention imparts excellent low moisture permeability to the optical film of the present invention. In general, the thicker the film, the higher the moisture permeability, and the thinner the film, the lower the moisture permeability. be. In addition, the resin layer of the present invention imparts excellent scratch resistance to the optical film of the present invention. tend to decline. Therefore, the optical film of the present invention having the resin layer of the present invention in a laminated structure such that the change rate is 20 or less imparts excellent low moisture permeability and scratch resistance even when the resin layer of the present invention is thin. It combines thinness with excellent low moisture permeability and durability.

The configuration in which the rate of change is 20 or less reduces the surface hardness and scratch resistance when the optical film of the present invention is used as a polarizing plate protective film, even if the resin layer of the present invention is thin. It is preferable in that it is possible to prevent the deterioration of the low moisture permeability due to scratches and suppress the occurrence of "color loss" of the polarizer. From the viewpoint of achieving both suppression of color loss of the polarizer and scratch resistance of the resin layer of the present invention at a higher level, the amount of change is preferably 18 or less, more preferably 15 or less, 12 or less, or 10 It may be below. The lower limit of the amount of change is not particularly limited, and is most preferably 0, that is, no change. It may be more than that.

In the optical film of the present invention, the moisture permeability M ¹ , M ² and M ³ , the product of the thickness T of the resin layer and the moisture permeability M ¹ , M ² or M ³ , the value ((1,000−M ¹ )/T), value ((2,000-M ² )/T), value ((2,700-M ³ )/T), their product, and change in moisture permeability before and after the scratch resistance test. can be specifically measured according to a known method, for example, JIS Z0208. In the optical film of the present invention, the moisture permeability M ¹ , M ² and M ³ , the product of the thickness T of the resin layer and the moisture permeability M ¹ , M ² or M ³ , the value ((1,000−M ¹ )/T), value ((2,000-M ² )/T), value ((2,700-M ³ )/T), their product, and change in moisture permeability before and after the scratch resistance test. can be adjusted by adjusting the type and thickness of the resin constituting the light-transmissive base material of the present invention, the above-described structure of the resin layer of the present invention, and the like.

Although the haze of the optical film of the present invention is not particularly limited, it is preferably 1.0% or less, more preferably 0.8% or less from the viewpoint of obtaining good transparency. Haze can be determined according to JIS K 7136 (2000). The haze of the optical film of the present invention can be adjusted by the type and thickness of the resin that constitutes the light-transmissive substrate of the present invention, the type and thickness of the resin that constitutes 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 85% or more, more preferably 88% or more. The visible light wavelength region can be determined according to JIS K 7361-1. The total light transmittance of the optical film 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 composition and thickness of the resin layer of the present invention, and the like. .

The thickness of the optical film of the present invention is not particularly limited, but is preferably in the range of 1 to 500 μm, more preferably 10 to 300 μm, in consideration of workability such as thinness, strength, and handleability. range, optimally in the range of 20-200 μm.

<Light transmissive substrate>
Materials constituting the light-transmitting substrate of the present invention include glass and plastic films. Examples of the plastic film include cellulose resins such as triacetyl cellulose (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), Cyclic olefin-based polymer (COP) (e.g., trade name "Arton" (manufactured by JSR Corporation), trade name "Zeonor" (manufactured by Zeon Co., Ltd.), etc.), polycarbonate-based resin, polysulfone-based resin, polyarylate-based Plastic materials such as resins, polyimide resins, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymers, etc., are optically uniform and have a smooth surface. Cellulose resins, acrylic resins, polyester resins, and cyclic olefin polymers (COP) are preferred, and cellulosic resins are particularly preferred, from the viewpoint of good secondary workability. 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. Haze can be determined according to JIS K 7136 (2000). The haze of the light-transmitting substrate of the invention can be adjusted by adjusting the type and thickness of the resin constituting the light-transmitting substrate of the 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 determined according to JIS K 7361-1. The total light transmittance of the light-transmitting substrate of the present invention can be adjusted by adjusting 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, but in consideration of thin layer properties, strength, workability such as handleability, and thin layer properties, it is preferably in the range of 1 to 500 μm. It is more preferably in the range of 10-300 μm, optimally in the range of 20-200 μm.

The refractive index of the light-transmitting substrate of the present invention is not particularly limited, but is, for example, in the range of 1.30-1.80, preferably in the range of 1.40-1.70. The surface of the light-transmitting substrate of the present invention (the surface on which the resin layer is formed and/or the surface opposite thereto) may be subjected to, for example, physical treatments such as corona discharge treatment and plasma treatment, undercoating treatment, and the like. A known and commonly used surface treatment such as chemical treatment may be applied as appropriate.

<Resin layer>
The resin layer of the present invention is laminated on one side of the light-transmitting substrate of the present invention, and imparts excellent low moisture permeability to the optical film of the present invention. Moreover, the resin layer of the present invention also 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 laminate structure can be suitably used as a polarizing plate protective film.

The surface of the resin layer of the present invention is preferably not scratched when subjected to a scratch resistance test using steel wool under the conditions of a load of 0.98 N, a moving speed of 100 mm/sec, and 10 reciprocations. That is, since the optical film of the present invention is coated with the resin layer of the present invention that has excellent scratch resistance, it is less likely to be scratched during the manufacturing process even if it is made thin, and when used as a polarizing plate protective film, it has excellent durability. It is possible to provide a polarizing plate excellent in The excellent scratch resistance of the resin layer of the present invention can be imparted by adjusting the above composition and thickness constituting the resin layer.

The resin layer of the present invention is a curable composition containing a polymerizable compound A having a cycloaliphatic hydrocarbon group and an unsaturated double bond group, and a polyfunctional polymerizable compound B other than the polymerizable compound A. It is formed from a cured product of A curable composition containing the polymerizable compounds A and B of the present invention may be referred to as "the curable composition of the present invention".

The cycloaliphatic hydrocarbon group of the polymerizable compound A has a highly hydrophobic chemical structure, and can impart excellent low moisture permeability to the resin layer. and scratch resistance tend to decrease. On the other hand, the polymerizable compound B is polyfunctional, and by increasing the crosslink density, it is possible to increase the scratch resistance of the resin layer. Therefore, it contains the polymerizable compound A and the polymerizable compound B, and the ratio (polymerizable compound A/polymerizable compound B) is formed from a cured product of a curable composition having a ratio of 95/5 to 10/90 The optical film of the present invention containing the resin layer of the present invention in a laminate structure can achieve both excellent low moisture permeability and excellent scratch resistance. The curable composition of the present invention may contain one type of polymerizable compound A, or may contain two or more types of polymerizable compound A. Moreover, the curable composition of the present invention may contain one type of polymerizable compound B, or may contain two or more types of polymerizable compound B.

The ratio of the polymerizable compound A and the polymerizable compound B (polymerizable compound A/polymerizable compound B) is preferably 10/90 or more from the viewpoint of imparting excellent low moisture permeability to the resin layer. /85 or more is more preferable, 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 or more, 55/45 or more, 60 /40 or greater, 65/35 or greater, 70/30 or greater, 75/25 or greater, 80/20 or greater, 85/15 or greater, or 90/10 or greater. On the other hand, from the viewpoint that the resin layer achieves both low moisture permeability and scratch resistance at a higher level, and from the viewpoint of preventing the occurrence of "color loss" of the polarizer by appropriately releasing moisture in the polarizing plate to the outside. , 95/5 or less, 90/10 or less, 85/15 or less, 80/20 or less, 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, 25/75 or less, 15/85 or less, or 10/90 or less.

As the unsaturated double bond group possessed by the polymerizable compound A, a (meth)acryloyl group, a vinyl group, a styryl group, an allyl group and the like are preferable, and a (meth)acryloyl group is particularly preferable. Especially preferred are the following compounds containing two or more (meth)acryloyl groups in one molecule.

The number of "unsaturated double bond groups" that the polymerizable compound A has in the molecule is not particularly limited as long as it is 1 or more, but the optical film of the present invention has excellent low moisture permeability and scratch resistance. In that respect, it preferably has 2 or more, more preferably 3 or more, and still more preferably 4 or more unsaturated double bond groups. Although the upper limit of the number of "unsaturated double bond groups" possessed by the polymerizable compound A is not particularly limited, it may be 10 or less, 9 or less, or 8 or less.

The "cycloaliphatic hydrocarbon group" that the polymerizable compound A has in the molecule is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably an alicyclic compound having 10 or more carbon atoms. It is a group derived from a compound, more preferably a group derived from an alicyclic compound having 12 or more carbon atoms. The cycloaliphatic hydrocarbon group is particularly preferably a group derived from a polycyclic compound such as bicyclic or tricyclic.

The cyclic aliphatic hydrocarbon group (including a linking group) is preferably a group represented by any one of the following general formulas (I) to (V), and the following general formulas (I), (II), or (IV) A group represented by is more preferable, and a group represented by the following general formula (I) is even more preferable.

In general formula (I), L and L' each independently represent a divalent or higher linking group. n represents an integer of 1 to 3;

In general formula (II), L and L' each independently represent a divalent or higher linking group. n represents an integer of 1-2.

In general formula (III), L and L' each independently represent a divalent or higher linking group. n represents an integer of 1-2.

In general formula (IV), L and L′ each independently represent a divalent or higher valent linking group, and L″ represents a hydrogen atom or a divalent or higher linking group.

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

Specific examples of cycloaliphatic hydrocarbon groups include monovalent to trivalent groups derived from norbornane, tricyclodecane, tetracyclododecane, pentacyclopentadecane, adamantane, diamantane, and the like.

The polymerizable compound A containing a group represented by any one of the general formulas (I) to (V) as a cycloaliphatic hydrocarbon group is represented by L, L′, and L″ via a linking group. It has a polymerizable functional group, and the linking group includes a single bond, an optionally substituted alkylene group having 1 to 6 carbon atoms, an optionally disubstituted amide group at the N-position, an N-substituted carbamoyl group, ester group, oxycarbonyl group, ether group and the like, and groups obtained by combining these.

The polymerizable compound A includes, for example, polyols such as diols and triols having a cycloaliphatic hydrocarbon group, and carboxylic acids and carboxylic acid derivatives of compounds having a (meth)acryloyl group, a vinyl group, a styryl group, an allyl group, and the like. , an epoxy derivative, an isocyanate derivative, etc., can be easily synthesized by a one-step or two-step reaction. Preferably, (meth)acrylic acid, (meth)acryloyl chloride, (meth)acrylic anhydride, glycidyl (meth)acrylate, 1,1-bis(acryloxymethyl)ethyl isocyanate, etc. are used to form the above cyclic It can be synthesized by reacting with a polyol having an aliphatic hydrocarbon group.

Preferred specific examples of the polymerizable compound A are shown below, but the present invention is not limited thereto.

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, the curable composition of the present invention 10% by weight or more, more preferably 15% by weight or more, or 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, or 35% by weight with respect to 100% by weight of non-volatile solids Above, 40% 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 or more. On the other hand, from the viewpoint that the resin layer of the present invention achieves both low moisture permeability and scratch resistance at a higher level, 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 , 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 , 20 wt % or less, 15 wt % or less, or 10 wt % or less.

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

In addition to the polymerizable compound B, it is a polyfunctional polymerizable compound other than the polymerizable compound A, that is, it does not have a cycloaliphatic hydrocarbon group in the molecule and has two or more polymerizable functional groups. is a compound. The polymerizable compound A tends to have low scratch resistance due to the steric structure of the cycloaliphatic hydrocarbon group in the molecule. It is believed that the inclusion of the polymerizable compound B in addition to the polymerizable compound A in the curable composition of the present invention increases the crosslink density and improves the scratch resistance.

The number of "polymerizable functional groups" possessed by the polymerizable compound B is not particularly limited as long as it is 2 or more, but preferably 3 or more in terms of imparting excellent scratch resistance to the optical film of the present invention. , more preferably 4 or more, or preferably 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more. Although the upper limit of the number of "polymerizable functional groups" possessed by the polymerizable compound B is not particularly limited, it may be 30 or less, 25 or less, or 20 or less. In particular, the number of "polymerizable functional groups" is preferably 5-10, more preferably 8-10.

As the polymerizable compound B, a monomer having no cycloaliphatic hydrocarbon group in the molecule and having two or more polymerizable functional groups (hereinafter sometimes referred to as "polymerizable monomer B"), Oligomers having no cycloaliphatic hydrocarbon group and having two or more polymerizable functional groups (hereinafter sometimes referred to as "polymerizable oligomer B") are exemplified. The curable composition of the present invention may contain only the polymerizable monomer 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. You can stay. From the viewpoint of being able to form a high degree of crosslink density, it preferably contains 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, and neopentyl glycol. Di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipenta Erythritol (meth)hexaacrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate and the like. The curable composition of the present invention may contain one type of polymerizable monomer B, or may contain two or more types of polymerizable monomers B.

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 its molecule. Examples of the polymerizable oligomer B include urethane (meth)acrylate obtained by adding two or more (meth)acryloyl groups as functional groups to a urethane skeleton, and two or more (meth)acryloyl groups as functional groups to a polyester skeleton. and epoxy (meth)acrylate obtained by adding two or more (meth)acryloyl groups as functional groups to the epoxy skeleton. From the viewpoint of being able to form a high crosslink density, it preferably contains at least urethane (meth)acrylate, and particularly preferably 5- to 10-functional urethane (meth)acrylate. The curable composition of the present invention may contain one type of polymerizable oligomer B, or may contain two or more types of polymerizable oligomer B.

Urethane (meth)acrylates are obtained, for example, by reacting polyols, isocyanates, and hydroxy (meth)acrylates.
As the polyol constituting the urethane (meth)acrylate, known polyols can be used without limitation. more preferably 6 or more), trimethylolpropane, ethoxylated isocyanuric acid, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, and the like. These polyols may be used alone or in combination of two or more.

Polyisocyanates composed of chain saturated hydrocarbons, cyclic saturated hydrocarbons, and aromatic hydrocarbons can be used as isocyanates that constitute urethane (meth)acrylates. Examples of such polyisocyanates include chain saturated hydrocarbon isocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, methylenebis(4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated toluene diisocyanate and other cyclic saturated hydrocarbon isocyanates, 2,4-tolylene diisocyanate, 1,3-xylylene diisocyanate, p-phenylene diisocyanate, 3,3' -dimethyl-4,4'-diisocyanate, 6-isopropyl-1,3-phenyl diisocyanate, 1,5-naphthalene diisocyanate and other aromatic polyisocyanates. Preferred specific examples include isophorone diisocyanate, tetramethylene diisocyanate and hexamethylene diisocyanate. These polyisocyanates may be used alone or in combination of two or more.

Examples of hydroxy (meth) acrylates constituting urethane (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) ) 6-hydroxyhexyl acrylate and the like. These hydroxy (meth)acrylates may be used alone or in combination of two or more.

Urethane (meth)acrylates include, for example, Artresin UN series manufactured by Neagari Kogyo Co., Ltd., NK Oligo U series manufactured by Shin-Nakamura Chemical Co., Ltd., and Shikou UV series manufactured by Mitsubishi Chemical Corporation.

A polyester (meth)acrylate is obtained, for example, by reacting (meth)acrylic acid with a terminal hydroxyl group of a polyester obtained by polymerizing a polyol and a polyvalent carboxylic acid. Specific examples of polyester (meth)acrylates include Aronix M-6000, Aronix M-7000, Aronix M-8000, and Aronix M-9000 manufactured by Toagosei Co., Ltd.

Epoxy (meth)acrylate is obtained, for example, by reacting epoxy resin with (meth)acrylic acid. Specific examples of epoxy (meth)acrylates include Lipoxy SP and Lipoxy 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, still more preferably 600 or more, and particularly preferably 600 or more. is greater than or equal to 700. Moreover, the weight average molecular weight of the polymerizable oligomer B is preferably 10,000 or less, more preferably 7,000 or less, and even more preferably 5,000 or less, from the viewpoint of coatability of the curable composition of the present invention. The weight average molecular weight of the polymerizable oligomer B can be determined, for example, by high performance liquid chromatography (HPLC). For example, using HPLC8020 manufactured by Tosoh Corporation as an apparatus, using two TSKgelGMH-H (20) connected in series as a column, using tetrahydrofuran as a solvent, under the conditions of a flow rate of 0.5 mL / min, Weight average molecular weight measurements can be made.

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 curable composition of the present invention 5% by weight or more, more preferably 10% by weight or more, and even more preferably 15% by weight or more, or 20% by weight or more, 25% by weight or more, 30% by weight or more, based on 100% by weight of nonvolatile solids, 35% by weight or more, 40% 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, It may be 85% by weight or more, or 90% by weight or more. On the other hand, from the viewpoint that the resin layer of the present invention achieves both low moisture permeability and scratch resistance at a higher level, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% 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, 20% by weight or less , 15 wt % or less, 10 wt % or less, or 5 wt % or less.

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 benzyl, benzophenone, benzoylbenzoic acid, benzophenone compounds such as 3,3′-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2- aromatic ketone compounds such as propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2 Acetophenone compounds such as -phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, benzoin ethyl ether, benzoin alkyl ether compounds such as benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; 1-phenone-1, 1_Photoactive oxime compounds such as propanedione-2-(o-ethoxycarbonyl)oxime; Thioxanthone compounds such as 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone and dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxide; These polymerization initiators may be used alone or in combination of two or more.

The content of the photopolymerization initiator in the curable composition of the present invention is not particularly limited, but from the viewpoint that the resin layer of the present invention sufficiently obtains low moisture permeability and scratch resistance, a polymerizable compound ( It is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, still more preferably 0.2 parts by weight or more, based on 100 parts by weight of the total of the polymerizable compound A and the polymerizable compound B). In addition, the content of the photopolymerization initiator in the curable composition of the present invention prevents the problem that the curable composition of the present invention is not sufficiently cured due to excessive radiation absorption by the photopolymerization initiator. From the viewpoint of suppression, it is preferably 10 parts by weight or less, more preferably 8 parts by weight or less, with respect to 100 parts by weight of the polymerizable compound (total of polymerizable compound A and polymerizable compound B).

Various leveling agents can be added to the curable composition of the present invention. As the leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used for the purpose of preventing coating unevenness (uniformizing the coated surface). A leveling agent may also be blended as appropriate when antifouling properties are required for the surface of the resin layer of the present invention.
The blending amount of the leveling agent is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the polymerizable compound (total of the polymerizable compound A and the polymerizable compound B). be.

The curable composition of the invention may contain a solvent. As the solvent, various solvents can be used in consideration of the solubility of the polymerizable compounds (polymerizable compound A and polymerizable compound B), drying properties during coating, and the like. Examples of such organic solvents include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate, carbonic acid. Methyl ethyl, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl cyclohexanone, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol, 2-butoxy Ethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexyl alcohol, isobutyl acetate, methyl isobutyl ketone (MIBK) , 2-octanone, 2-pentanone, 2-hexanone, ethylene 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., and can be used singly or in combination of two or more.

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

The film thickness of the resin layer of the present invention is preferably 0.5 to 5 μm. As described above, even if the resin layer of the present invention is thin, it can impart excellent low moisture permeability and scratch resistance 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 resin layer is preferably 4.5 μm or less, preferably 4 μm or less, and 3.2 μm from the viewpoint that the polarizing plate can be made thinner. or less, or 3 μm or less. The lower limit of the film thickness of the resin layer of the present invention is preferably 1.0 μm or more, more preferably 1.8 μm or more, and 2 μm or more from the viewpoint of achieving both low moisture permeability and scratch resistance at a higher level. There may be. The resin layer of the present invention may be a single layer or a plurality of layers. When the resin layer of the present invention is composed of a plurality of layers, the film thickness of the resin layer of the present invention is the sum of the layers constituting the plurality of layers.

The resin layer of the present invention comprises a polymerizable compound A and a polymerizable compound B, optionally a polymerizable compound other than the polymerizable compound A and the polymerizable compound B, a photopolymerization initiator, a leveling agent, a solvent, and other By mixing with additives and the like to prepare a coating liquid (curable composition of the present invention), coating and drying the coating liquid on one side of a light-transmitting substrate, and curing the coating film can be formed.

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

Examples of methods for applying the coating solution include dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, die coating, extrusion coating, bar coating, and the like. be done.

Curing of the coating film is appropriately selected according to the type of the curable composition and the like. When the curable composition is photocurable, it can be cured by irradiating it with light using a light source that emits light of an appropriate wavelength. As the irradiation light, 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. Moreover, you may heat in the case of a photocuring process.
Examples of the light include ionizing radiation such as α-rays, β-rays, γ-rays, neutron beams and electron beams, and ultraviolet rays, with ultraviolet rays being particularly preferred. Moreover, the irradiation time, the irradiation method, and the like are not particularly limited as long as the photopolymerization initiator can be activated to cause the reaction of the polymerizable compound.

<Polarizing plate>
The polarizing plate of the present invention has a laminated structure in which a polarizer is arranged on the opposite side of the resin layer of the optical film of the present invention. 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 from the resin layer 1 . Since the optical film 10 is used as a polarizing plate protective film, the polarizing plate 20 has excellent low moisture permeability and scratch resistance even if the resin layer 1 is thin, and quality deterioration such as color loss of the polarizer 3 is prevented. is less likely to occur. In this embodiment, on the opposite side of the polarizer 3 from the optical film 10, a second light-transmitting substrate 4 and an adhesive layer 5 are further laminated in this order.

The polarizer 3 is an element that allows only light with a plane of polarization in a certain direction to pass through, and any known polarizer 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 dyed with a dichroic dye.

The polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a dichroic dye (preferably a film further subjected to durability treatment with a boron compound); A film obtained by dyeing an alcohol-based film with iodine or a dichroic dye and then uniaxially stretching the film (preferably, a film further subjected to a durability treatment with a boron compound) may be used. The absorption axis of the polarizer is parallel to the stretching direction of the film.

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

The second light-transmitting substrate 4 protects the opposite side of the polarizer 3 from the optical film 10 (polarizing plate protective film), and is similar to the light-transmitting substrate of the present invention, such as a glass or plastic film. Cellulose-based resins, cyclic olefin-based polymers (COP), and polycarbonate-based resins are preferred, and cyclic olefin-based polymers (COP) and polycarbonate-based resins are more preferred. The light transmissive substrate 4 may be made of the same material as the light transmissive substrate 2, or may be made of a different material. The light-transmitting base material 4 may be one in which the resin layer 1 is laminated, or may not have the resin layer 1 . Further, the light-transmissive base material 4 may be composed of a single layer, or may be a laminated structure of two or more layers that are the same or different.

Also, the light-transmitting substrate 4 is preferably an optical compensation film (retardation film) having an optical compensation layer containing an optically anisotropic layer. An optical compensation film can improve the viewing angle characteristics of a liquid crystal display screen, for example. As the optical compensation film, known ones can be used without limitation, and for example, a retardation film described in JP-A-2014-194484 may be used.

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

The adhesive layer 5 is made of any appropriate adhesive. Materials constituting the adhesive layer 5 include, for example, acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine polymers, rubber polymers, isocyanate polymers, polyvinyl alcohol polymers, and gelatin polymers. , vinyl-based polymers, latex-based polymers, water-based polyesters, and other polymer-based materials. Among them, a material having an acrylic polymer and/or a rubber polymer as a base polymer is preferable from the viewpoint of low moisture permeability. 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 more preferably 10 to 20 μm from the viewpoint of thinning the polarizing plate 20 .

The polarizing plate 20 can be obtained by bonding the polarizer 1 and the optical film 10 together with an adhesive. Also, the polarizer 1 and the light-transmitting substrate 4 can be attached together with an adhesive. The adhesive used for bonding may be a completely saponified polyvinyl alcohol aqueous solution (water paste), or an active energy ray-curable adhesive.

The pressure-sensitive adhesive layer 5 can be formed by applying a pressure-sensitive adhesive composition containing a base polymer that constitutes the pressure-sensitive adhesive to the light-transmitting substrate 4, drying it, and then curing it as necessary. Alternatively, the pressure-sensitive adhesive layer 5 may be formed on the separator in the same manner, and may be formed by sticking and transferring to the light-transmitting substrate 4 .

A layer other than the polarizing plate 20, the optical film 10, the polarizing plate 3, the light-transmitting substrate 4, and the adhesive layer 5 (for example, a surface protective film, a separator, etc.) may be provided on the surface or between any layers. For example, the surface of the adhesive layer 5 may be protected with a separator, and the surface of the resin layer 1 of the optical film 10 may be protected with a surface protective film.

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

<Image display device>
The image display device of the present invention has the polarizing plate of the present invention. Since the image display device of the present invention has the polarizing plate of the present invention in a laminated structure, it has excellent low moisture permeability and scratch resistance even if the resin layer 1 is thin, and quality such as color loss of the polarizer 3 Less likely to deteriorate. Therefore, even if the image display device of the present invention is thin, the polarizing plate is less likely to lose color in a humidified environment, and is excellent in durability.
In FIG. 3 , an image display device 30 has an image display panel 6 laminated on an adhesive layer 5 of a polarizing plate 20 . In this embodiment, an adhesive layer 7 and an optical member 8 are laminated in this order on the resin layer 1 .

Examples of the image display panel 6 include, but are not limited to, a liquid crystal image display panel, a self-luminous image display panel (eg, an organic EL (electroluminescence) image display panel, an LED image display panel), and the like.

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

The adhesive layer 7 can use a material containing a base polymer similar to those exemplified for the adhesive layer 5 . Among them, a material having an acrylic polymer and/or a rubber polymer as a base polymer is preferable from the viewpoint of low moisture permeability. The adhesive layer 7 may contain a single base polymer, or may contain two or more base polymers. The adhesive layer 7 may be made of the same material as the adhesive layer 5, or may be made of a different material.

The optical member 8 can be made of the same glass, plastic film, or the like as the light-transmitting substrate of the present invention. Acrylic resins, polyester resins, and cyclic olefin polymers (COP) are preferred, and polyester resins are particularly preferred. preferable. When the optical member 8 is positioned on the outermost surface of the image display device 30 on the viewing side, the optical member 8 functions as a cover member.

The image display device 30 includes an optical member other than the optical film 10, the polarizing plate 3, the light-transmitting substrate 4, the adhesive layer 5, the image display panel 6, the adhesive layer 7, and the optical member 8, on the surface or any It may be provided between layers. Examples of the optical member include, but are not particularly limited to, a polarizing plate other than the polarizing plate 3, a retardation plate, an antireflection film, a viewing angle adjusting film, an optical compensation film, and the like. Note that the optical member includes members (design film, decorative film, surface protection plate, etc.) that play a role of decoration and protection while maintaining the visibility of the image display device and the input device.

The image display device 30 can be manufactured by laminating an optical film in which the image display panel 6, the polarizing plate 20, the optical member 8, and the adhesive layer 7 are laminated. / Or it can be carried out by laminating under pressure. Curing may be performed by irradiating active energy rays after lamination under heat and/or pressure. Irradiation with active energy rays can be performed in the same manner as in the formation of the resin layer of the present invention.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

Example 1
(Preparation of coating solution for forming resin layer)
As the resin contained in the resin layer, UV-curable acrylate resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “A-DCP”, solid content 100%) 90 parts by weight (solid content conversion), UV-curable acrylate resin ( Mitsubishi Chemical Corporation, trade name "UV-1700TL", solid content 80%) 10 parts by weight (solid content conversion) was prepared. Per 100 parts by weight of the resin solid content of the resin, 5 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907"), a leveling agent (manufactured by Kyoeisha Chemical Co., Ltd., trade name "LE-303", solid 40% by weight) was mixed. This mixture was diluted with an MIBK/cyclopentanone mixed solvent (weight ratio: 60/40) so that the solid content concentration was 30%, to prepare a resin layer-forming coating solution.

(Preparation of optical film)
A transparent plastic film substrate (TAC, manufactured by FUJIFILM Corporation, trade name “TJ25UL”) was prepared as a light-transmissive substrate. A coating film was formed on one side of the transparent plastic film substrate using the coating solution for forming the resin layer prepared above using a bar coater #7. Then, the transparent plastic film substrate on which this coating film was formed was transported to a drying step. In the drying step, the coating film was dried by heating at 60° C. for 1 minute. Thereafter, the coating film was cured by irradiating ultraviolet light with an accumulated light quantity of 220 mJ/cm ² using a high-pressure mercury lamp to form a resin layer having a thickness of 2.5 μm.
Details of the resins used in Example 1 are as follows.
・A-DCP: tricyclodecanedimethanol dimethacrylate ・UV-1700TL: 10-functional urethane acrylate

Example 2
Example 1 was performed in the same manner as in Example 1, except that 70 parts by weight (calculated as solid content) of A-DCP and 30 parts by weight (calculated as solid content) of UV-1700TL were blended as the resins contained in the resin layer. No. 2 optical film 2 was obtained.

Example 3
In the same manner as in Example 1, except that 50 parts by weight (calculated as solid content) of A-DCP and 50 parts by weight (calculated as solid content) of UV-1700TL were blended as the resin contained in the resin layer. An optical film 3 of No. 3 was obtained.

Comparative example 1
An optical film 4 of Comparative Example 1 was obtained in the same manner as in Example 1, except that 100 parts by weight (in terms of solid content) of A-DCP was blended as the resin contained in the resin layer.

Comparative example 2
An optical film 5 of Comparative Example 2 was obtained in the same manner as in Example 1, except that 100 parts by weight (in terms of solid content) of UV-1700TL was blended as the resin contained in the resin layer.

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

(1) Film thickness measurement A digital linear gauge (trade name “MODEL D-10HS”, manufactured by Ozaki Seisakusho Co., Ltd.) was used to measure the film thickness of the optical films of Examples and Comparative Examples at five points across the width. , and the average value of the film thickness at 5 points was taken as the total thickness. The film thickness of the light-transmitting substrates used in Examples and Comparative Examples was measured by the same method, and the average value of the five film thicknesses was taken as the substrate thickness. The difference between the total thickness and the substrate thickness was taken as the thickness of the resin layer.

(2) Measurement of moisture permeability The optical films of Examples and Comparative Examples were measured for moisture permeability at 40°C and 92% relative humidity in accordance with JIS Z0208.

(3) Evaluation of color loss of polarizer The optical films of Examples and Comparative Examples were stored in a 60° C., 90% environment for 120 hours, and then the films were removed in a darkroom with the backlight illuminance set to 8000 candela. When color loss such as unevenness or streaks was visually observed during observation, it was determined that the polarizer had color loss.

(4) Scratch resistance measurement The optical films of Examples and Comparative Examples were cut into a size of 5 cm x 15 cm, and were placed on the surface of the resin layer so that the diameter was 2.5 cm and the contact area was 6.25 x π cm ² . , #0000 steel wool. A load of 100 gf (0.98 N) was applied to the steel wool, and the surface of the resin layer was rubbed back and forth 10 times at a moving speed of 100 mm/s in the longitudinal direction of the film.
Under the environment of a fluorescent lamp and an LED light source, the presence or absence of scratches on the central 5 cm×5 cm portion of the film after the test was visually determined.

(5) Moisture permeability measurement The temperature and humidity conditions for the test are set to a temperature of 60 ° C. and a relative humidity of 90%, or a temperature of 65 ° C. and a relative humidity of 90%, and the temperature and humidity conditions are 40 ° C. and 92%. of the optical film was measured.
The product of the thickness [μm] of the resin layer and the moisture permeability [g/m ² 24 h] of the optical film in an environment of 40° C. and 92% relative humidity (1), the thickness [μm] of the resin layer and the temperature The product (2) of the moisture permeability [g/m ² 24 h] of the optical film at 60°C and 90% relative humidity, the thickness [μm] of the resin layer and the temperature at 65°C and 90% relative humidity The product (3) of the moisture permeability [g/m ² · 24 h] of the optical film at the time, the product ((1) × (2)) of the product (1) and the product (2), from 1,000, the temperature of 40 ° C. , the value obtained by subtracting the moisture permeability [g/m ² 24 h] of the optical film in an environment of 92% relative humidity and dividing it by the thickness [μm] of the resin layer (4), 2,000, temperature 60 ℃, the value obtained by subtracting the moisture permeability [g/m ² 24h] of the optical film in an environment of 90% relative humidity and dividing it by the thickness [μm] of the resin layer (5), from 2,700, the temperature Value (6) and value (4) obtained by dividing the value obtained by subtracting the moisture permeability [g/m ² 24h] of the optical film in an environment of 65°C and relative humidity of 90% by the thickness [μm] of the resin layer. Table 2 shows the product of values (5) ((4) x (5)).

(6) Measurement of Moisture Permeability after Scratch Resistance Test The optical films of Examples ² and 3 were cut into a size of 5 cm×15 cm. #0000 steel wool was brought into contact. A load of 400 gf (3.92 N) was applied to the steel wool, and the surface of the resin layer was rubbed back and forth 10 times at a moving speed of 100 mm/s in the long side direction of the film. Water vapor transmission rate was measured at 92% humidity.
The amount of change in moisture permeability after the scratch resistance test was 9 g/m 2 ·24 h in Example ^{2 and 1 g/m 2 ·} 24 h in Example 3.

Variations of the present invention are appended below.
[Appendix 1] An optical film in which a resin layer is laminated on one surface of a light-transmitting substrate,
The resin layer comprises a polymerizable compound A having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group, and a polyfunctional polymerizable compound B other than the polymerizable compound A. Curing of a curable composition containing made of matter,
The optical film, wherein the ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A/polymerizable compound B) is from 95/5 to 10/90.
[Appendix 2] The optical film according to Appendix 1, wherein the polymerizable compound B is a 5- to 10-functional urethane (meth)acrylate.
[Appendix 3] The optical film according to Appendix 1 or 2, wherein the film thickness of the resin layer is 0.5 to 5 μm.
[Appendix 4] Any one of Appendices 1 to 3, wherein the light-transmitting substrate contains at least one selected from the group consisting of cellulose-based resins, polyester-based resins, acrylic-based resins, and cyclic olefin-based polymers. The optical film described in .
[Appendix 5] A polarizing plate in which a polarizer is arranged on the side of the optical film according to any one of Appendices 1 to 4 opposite to the resin layer.
[Appendix 6] An image display device comprising the polarizing plate according to Appendix 5.
[Appendix 7] The image display device according to Appendix 6, wherein an adhesive layer and an optical member are laminated in this order on the resin layer.

10 optical film 1 resin layer 2 light transmissive substrate 20 polarizing plate 3 polarizer 4 light transmissive substrate (optical compensation film)
5 adhesive layer 30 image display device 6 image display panel 7 adhesive layer 8 optical member

Claims (7)

An optical film in which a resin layer is laminated on one surface of a light-transmitting substrate,
The resin layer comprises a polymerizable compound A having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group, and a polyfunctional polymerizable compound B other than the polymerizable compound A. Curing of a curable composition containing made of matter,
The optical film, wherein the ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A/polymerizable compound B) is from 95/5 to 10/90. 2. The optical film according to claim 1, wherein the polymerizable compound B is a 5- to 10-functional urethane (meth)acrylate. 3. The optical film according to claim 1, wherein the resin layer has a thickness of 0.5 to 5 μm. 4. The light-transmitting substrate according to any one of claims 1 to 3, wherein the light-transmitting substrate contains at least one selected from the group consisting of cellulose-based resins, polyester-based resins, acrylic-based resins, and cyclic olefin-based polymers. optical film. A polarizing plate comprising a polarizer disposed on the side of the optical film according to any one of claims 1 to 4 opposite to the resin layer. An image display device comprising the polarizing plate according to claim 5 . 7. The image display device according to claim 6, wherein an adhesive layer and an optical member are laminated in this order on the resin layer.

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