Optical film

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

Technical Field

[0001] The present invention relates to an optical film. More specifically, it relates to an optical film suitable for a polarizer protection film.

Background Art

[0002] In an image display device (for example, a liquid crystal display device, an organic EL display device, etc.), in many cases, a polarizer is disposed on at least one side of a display cell due to its image formation method. The polarizer plays a role of passing only light with a polarization plane in a certain direction, and the performance of the image display device depends greatly on the performance of the polarizer. Generally, a polarizer is composed of a polyvinyl alcohol film or the like in which iodine or a dye is adsorbed and oriented, and a transparent protective film (polarizer protection film) is bonded to at least one surface of the polarizer (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, the market for mobile applications such as smartphones and tablet terminals has expanded, and the need for thinning of image display devices has increased further, and thinning of members constituting a polarizer such as a polarizer protection film is also required. However, as the thickness of the polarizer protection film decreases, there is a problem that the protection function for the polarizer deteriorates.

[0005] For example, when the polarizer protection film becomes thin, the permeability (moisture permeability) to moisture increases, and the polarization performance of the polarizer disappears in a humid environment, and a phenomenon called "color leakage" may occur.

[0006] In addition, when the polarizer protection film becomes thinner, there are problems such as a decrease in surface hardness and scratch resistance, increased susceptibility to damage during the manufacturing process, and a decrease in the low moisture permeability of the polarizer. Therefore, the optical film used for the polarizer protection film is also required to have excellent scratch resistance.

[0007] In order to enhance the low moisture permeability of the polarizer protection film, it is necessary to introduce a highly hydrophobic structure as the resin constituting the film. However, a chemical structure with high hydrophobicity generally has a bulky structure and tends to be sparse, resulting in a problem that the surface hardness and scratch resistance are likely to decrease. That is, the low moisture permeability and scratch resistance are in a trade-off relationship, and it is generally difficult to achieve both.

[0008] The present invention has been conceived under the above circumstances, and an object of the present invention is to provide an optical film suitable for a polarizer protection film that can achieve both excellent low moisture permeability and scratch resistance even when made thin.

Means for Solving the Problems

[0009] That is, 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 resin layer imparts excellent low moisture permeability to the optical film of the first aspect of the present invention. In addition, the resin layer also imparts excellent scratch resistance to the optical film of the first aspect of the present invention. Therefore, the optical film of the first aspect of the present invention having the resin layer in a laminated structure is suitable for a polarizer protection film.

[0010] In the optical film of the first aspect of the present invention, the resin layer is formed of a cured product of a curable composition containing a polymerizable compound A having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group, and a polymerizable compound B other than the polymerizable compound A. 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.

[0011] 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, which can impart excellent low moisture permeability to the resin layer. However, due to its bulky nature, the structure tends to be loose, and the surface hardness and scratch resistance are likely to decrease. On the other hand, the polymerizable compound B is polyfunctional, and by increasing the crosslinking density, the scratch resistance of the resin layer can be enhanced. Therefore, the resin layer formed of the cured product of the curable composition containing the polymerizable compound A and the polymerizable compound B, and having a ratio (polymerizable compound A / polymerizable compound B) of 95 / 5 to 10 / 90, included in the laminated structure of the optical film of the first aspect of the present invention can achieve both excellent low moisture permeability and scratch resistance.

[0012] From the viewpoint of imparting excellent low moisture permeability to the resin layer, the ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A / polymerizable compound B) is preferably 10 / 90 or more, more preferably 15 / 85 or more, or may be 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 more, 65 / 35 or more, 70 / 30 or more, 75 / 25 or more, 80 / 20 or more, 85 / 15 or more, or 90 / 10 or more. On the other hand, from the viewpoints of achieving both low moisture permeability and scratch resistance at a higher level in the resin layer, and preventing the occurrence of "color bleeding" of the polarizer by appropriately discharging moisture in the polarizing plate to the outside, it may be 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.

[0013] 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 crosslinking density of the resin layer and improving the scratch resistance.

[0014] 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 made thin, excellent low moisture permeability and scratch resistance can be imparted to the optical film according to the first aspect of the present invention. When the optical film according to the first aspect of the present invention is used as a polarizing plate protective film, from the viewpoint of making the polarizing plate thinner, the film thickness of the resin layer is preferably 4.5 μm or less, preferably 4 μm or less, and may be 3.2 μm or less, or 3 μm or less. As the lower limit value of the film thickness of the resin layer, from the viewpoint of achieving both low moisture permeability and scratch resistance at a higher level, 1.0 μm or more is preferable, more preferably 1.8 μm or more, and may be 2 μm or more.

[0015] In the optical film according to the first aspect of the present invention, it is preferable that the light-transmissive base material contains at least one selected from the group consisting of a cellulose-based resin, a polyester-based resin, an acrylic-based resin, and a cyclic olefin-based polymer. These resins can be suitably used as the base material of the polarizing plate protective film.

[0016] Further, the second 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 according to the first aspect of the present invention. Furthermore, the third aspect of the present invention provides an image display device having the polarizing plate according to 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.

[0017] Since the optical film according to the first aspect of the present invention is used as a polarizing plate protective film in the polarizing plate according to the second aspect of the present invention, the resin layer has excellent low moisture permeability and scratch resistance even if it is thin. Therefore, the image display device according to the third aspect of the present invention having the polarizing plate according to the second aspect of the present invention is less likely to cause color bleeding or the like of the polarizing plate in a humid environment and has excellent durability even when it is thin.

Effects of the Invention

[0018] The polarizing plate obtained by using the optical film of the present invention as a polarizing plate protective film has excellent low moisture permeability and scratch resistance even when it is made thin, is less likely to cause color leakage of the polarizer, and has excellent durability.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0020] The 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 as "the optical film of the present invention" in this specification. Also, the light-transmissive substrate and the resin layer constituting the optical film of the present invention may be referred to as "the light-transmissive substrate of the present invention" and "the resin layer of the present invention", respectively, in this specification. Further, "film" shall include the meanings of "sheet" and "tape". That is, the optical film of the present invention may have a form on a sheet or tape.

[0021] The second 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. The polarizing plate of the second aspect of the present invention may be referred to as "the polarizing plate of the present invention" in this specification. Further, the third aspect of the present invention provides an image display device having the polarizing plate of the present invention. The image display device of the third aspect of the present invention may be referred to as "the image display device of the present invention" in this specification.

[0022] Hereinafter, embodiments of the optical film of the present invention will be described in relation to the drawings. However, the present invention is not limited thereto and is merely illustrative.

[0023] FIG. 1 is a schematic diagram (cross-sectional view) showing an embodiment of the optical film of the present invention. In FIG. 1, the optical film 10 has a laminated structure in which a resin layer 1 is laminated on one surface of a light-transmissive substrate 2.

[0024] FIG. 2 is a schematic diagram (cross-sectional view) showing an embodiment of the polarizing plate of the present invention. In FIG. 2, the polarizing plate 20 has a laminated structure in which a polarizer 3 is disposed on the side opposite to the resin layer 1 of the optical film 10. In this embodiment, a second light-transmissive substrate 4 and an adhesive layer 5 are further laminated in this order on the side of the polarizer 3 opposite to the optical film 10.

[0025] FIG. 3 is a schematic diagram (cross-sectional view) showing an embodiment of an image display device having the polarizing plate of FIG. 2. In the image display device 30 of FIG. 3, an image display panel 6 is 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. Hereinafter, each component will be described.

[0026] <Optical Film> "Optical" in the optical film of the present invention means being used for optical applications. More specifically, it means being used in the manufacture of products (optical products) in which optical members are used. Examples of optical products include input devices such as image display devices and touch panels, and it can be preferably used in the manufacture of liquid crystal image display devices, self-emitting type image display devices (for example, organic EL (electroluminescence) image display devices, LED image display devices), etc. More specifically, it can be preferably used as a protective film for the polarizing plate constituting the image display device.

[0027] The form of the optical film of the present invention is not particularly limited as long as a resin layer is laminated on one surface of the light-transmissive substrate. For example, the optical film of the present invention may have a resin layer on only one side or may have resin layers on both sides. Further, 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, or one resin layer is provided by the resin layer of the present invention and the other resin layer is provided by a resin layer other than the resin layer of the present invention (other resin layer). When the optical film of the present invention is used as a polarizer protection film, an optical film having a resin layer on only one side is preferable.

[0028] In addition to the light-transmissive substrate and the resin layer of the present invention, the optical film of the present invention may have other layers, for example, a substrate other than the light-transmissive substrate of the present invention, 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 protection film, etc. on the surface or between any layers, as long as the effects of the present invention are not impaired.

[0029] The moisture permeability M of the optical film of the present invention under the environment of a temperature of 40 ° C and a relative humidity of 92% 1 [g / m 2 ·24 h] is preferably 700 g / m 2 ·24 h or less. The moisture permeability M 1 being 700 g / m 2 ·24 h or less is preferable in that it can suppress the occurrence of "color bleeding" of the polarizer in a humid environment when the optical film of the present invention is used as a polarizer protection film. From the viewpoint of suppressing the occurrence of color bleeding of the polarizer at a higher level, the moisture permeability M 1 is preferably 600 g / m 2 ·24 h or less, and may be 550 g / m 2 ·24 h or less. The lower limit value of the moisture permeability M 1 is not particularly limited, but from the viewpoint of preventing the moisture in the polarizer from escaping to the outside and preventing the occurrence of "color bleeding" of the polarizer, it is preferably 100 g / m 2 ·24 h or more, and preferably 200 g / m 2· More preferably, it is 24 hours or more, 300 g / m 2 · 24 hours or more, 310 g / m 2 · 24 hours or more, or 320 g / m 2 · It may be 24 hours or more.

[0030] The moisture permeability M of the optical film of the present invention under the environment of a temperature of 60 °C and a relative humidity of 90% 2 [g / m 2 · 24h] is 1,500 g / m 2 · Preferably, it is 1,500 g / m·24h or less. The moisture permeability M 2 being 1,500 g / m 2 · The configuration of being 1,500 g / m·24h or less is preferable in that when the optical film of the present invention is used as a polarizing plate protective film, the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of suppressing the occurrence of color leakage of the polarizer at a higher level, the moisture permeability M 2 is preferably 1,400 g / m 2 · 24h or less, more preferably 1,300 g / m 2 · 24h or less, and may even be 1,200 g / m 2 · 24h or less. The lower limit of the moisture permeability M 2 is not particularly limited, but from the viewpoint of preventing the occurrence of "color leakage" of the polarizer by allowing the moisture in the polarizing plate to escape to the outside, it is preferably 300 g / m 2 · 24h or more, more preferably 500 g / m 2 · 24h or more, and may even be 800 g / m 2 · 24h or more.

[0031] The moisture permeability M of the optical film of the present invention under the environment of a temperature of 65 °C and a relative humidity of 90% 3 [g / m 2 · 24h] is 2,000 g / m 2 · Preferably, it is 2,000 g / m·24h or less. The moisture permeability M 3 being 2,000 g / m 2 · The configuration of being 2,000 g / m·24h or less is preferable in that when the optical film of the present invention is used as a polarizing plate protective film, the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of suppressing the occurrence of color leakage of the polarizer at a higher level, the moisture permeability M3 is preferably 1,800 g / m 2 ·24 h or less, more preferably 1,600 g / m 2 ·24 h or less, and may even be 1,400 g / m 2 ·24 h or less. The lower limit of the moisture permeability M 3 is not particularly limited, but from the viewpoint of preventing the occurrence of "color leakage" of the polarizer by allowing the moisture inside the polarizing plate to escape to the outside, it is preferably 500 g / m 2 ·24 h or more, more preferably 750 g / m 2 ·24 h or more, and may even be 1,000 g / m 2 ·24 h or more.

[0032] 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 of the optical film of the present invention under the environment of a temperature of 40°C and a relative humidity of 92% 1 [g / m 2 ·24 h] product (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. Generally, the moisture permeability tends to increase as the film thickness increases, and decreases as the film thickness decreases, showing an inverse proportional relationship. Therefore, the product (T × M 1 ) of the thickness T [μm] of the resin layer of the present invention and the moisture permeability M 1 can be an index of the moisture permeability of the resin layer of the present invention itself, and it can be said that the lower it is, the more excellent the low moisture permeability. Therefore, the optical film of the present invention having a laminated structure with the resin layer of the present invention in which the above product (T × M 1 ) is 1,500 or less is provided with excellent low moisture permeability even when the resin layer of the present invention is thin, and has both a thin thickness and excellent low moisture permeability.

[0033] The product (T × M 1The configuration where ( ) is 1,500 or less is preferable in that, when the optical film of the present invention is used as a polarizer protection film, excellent low moisture permeability can be imparted even when the resin layer of the present invention is thin, and the occurrence of "color bleeding" of the polarizer can be suppressed in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color bleeding of the polarizer and further 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, and may be 1,200 or less. The lower limit of the product (T×M 1 ) is not particularly limited, but from the viewpoint of preventing the occurrence of "color bleeding" of the polarizer by allowing moisture in the polarizer to escape to the outside, it is preferably 500 or more, more preferably 600 or more, and may be 700 or more.

[0034] 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 of the optical film of the present invention under the environment of 60 ° C. and 90% relative humidity 2 [g / m 2 ·24h] of the product (T×M 2 ) is preferably 3,000 or less. The product (T×M 2 ) can also be an index of the moisture permeability of the resin layer itself of the present invention, similar to the above product (T×M 1 ), and it can be said that the lower it is, the more excellent the low moisture permeability. Therefore, the optical film of the present invention having a laminated structure with the resin layer of the present invention where the product (T×M 2 ) is 3,000 or less is preferably provided with excellent low moisture permeability even when the resin layer of the present invention becomes thin, and has both thinning and excellent low moisture permeability.

[0035] The configuration where the product (T×M 2 ) is 3,000 or less is preferable in that, when the optical film of the present invention is used as a polarizer protection film, the occurrence of "color bleeding" of the polarizer can be suppressed in a humid environment even when the resin layer of the present invention is thin. From the viewpoint of achieving both suppression of the occurrence of color bleeding of the polarizer and further thinning of the resin layer of the present invention at a higher level, the above product (T×M 2) is preferably 2,900 or less, more preferably 2,800 or less, and may be 2,700 or less. The product (T×M 2 ) has no particular lower limit, but from the viewpoint of preventing the occurrence of "color leakage" of the polarizer by allowing moisture in the polarizing plate to escape to the outside, it is preferably 500 or more, more preferably 1,000 or more, and may be 1,500 or more.

[0036] In the optical film of the present invention, the product (T×M 1 ) and the product (T×M 2 ) of the product ((T×M 1 ))×(T×M 2 )) is preferably 4,500,000 or less. The product ((T×M 1 ))×(T×M 2 )) is also, like the product (T×M 1 ) and the product (T×M 2 ), an index of moisture permeability that the resin layer of the present invention itself can have, and it can be said that the lower it is, the better the low moisture permeability. Therefore, the optical film of the present invention having a laminated structure of the resin layer of the present invention in which the product ((T×M 1 ))×(T×M 2 )) is 4,500,000 or less is preferably provided with excellent low moisture permeability even when the resin layer of the present invention is thin, and has both thinness and excellent low moisture permeability.

[0037] The configuration in which the product ((T×M 1 ))×(T×M 2 )) is 4,500,000 or less is preferable in that when the optical film of the present invention is used as a polarizing plate protective film, even when the resin layer of the present invention is thin, the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color leakage of the polarizer and thinning of the resin layer of the present invention at a higher level, the above product ((T×M 1 ))×(T×M 2 )) is preferably 4,000,000 or less, more preferably 3,500,000 or less. The product ((T×M 1 ))×(T×M 2The lower limit of () is not particularly limited, but from the viewpoint of preventing the occurrence of "color leakage" of the polarizer by allowing moisture in the polarizing plate to escape to the outside, 50,000 or more is preferable, 100,000 or more is more preferable, and 150,000 or more may be sufficient.

[0038] 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 of the optical film of the present invention under the environment of a temperature of 65 ° C and a relative humidity of 90% 3 [g / m 2 ·24h] of the product (T×M 3 ) is preferably 4,000 or less. The product (T×M 3 ) is also, like the above product (T×M 1 ), product (T×M 2 ), an index of the moisture permeability provided by the resin layer itself of the present invention, and it can be said that the lower it is, the more excellent the low moisture permeability is. Therefore, the optical film of the present invention having a laminated structure with the resin layer of the present invention having the product (T×M 3 ) of 4,000 or less is preferably provided with excellent low moisture permeability even when the resin layer of the present invention is thin, and has both thinness and excellent low moisture permeability.

[0039] The configuration in which the product (T×M 3 ) is 4,000 or less is preferable in that, when the optical film of the present invention is used as a polarizing plate protective film, even when the resin layer of the present invention is thin, the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color leakage of the polarizer and thinning of the resin layer of the present invention at a higher level, the product (T×M 3 ) is preferably 3,800 or less, more preferably 3,600 or less, and may be 3,400 or less. The lower limit of the product (T×M 3 ) is not particularly limited, but from the viewpoint of preventing the occurrence of "color leakage" of the polarizer by allowing moisture in the polarizing plate to escape to the outside, 1,000 or more is preferable, 1,500 or more is more preferable, and 2,000 or more may be sufficient.

[0040] In the optical film of the present invention, from 1,000 to the moisture permeability M of the optical film under the environment of a temperature of 40 ° C and a relative humidity of 92%1 [g / m 2 ·24 h], divided by the thickness T [μm] of the resin layer, the value ((1,000 - M 1 )) / T) 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. Generally, the moisture permeability tends to increase as the film thickness increases, and the moisture permeability tends to decrease as the film thickness decreases. The above numerical value "1,000" is an approximate value of the moisture permeability of the light-transmissive base material itself (light-transmissive base material having no resin layer) of the present invention under the environment of a temperature of 40 ° C and a relative humidity of 92%. The value obtained by subtracting the moisture permeability M 1 [g / m 2 ·24 h] is an approximate value of the reduced moisture permeability due to providing the resin layer on the light-transmissive base material of the present invention. Therefore, the value ((1,000 - M 1 )) / T) can be an index of the moisture permeability reduced per 1 μm thickness of the resin layer of the present invention under the environment of a temperature of 40 ° C and a relative humidity of 92%, and it can be said that the higher the value, the more excellent the low moisture permeability. Therefore, the optical film having the resin layer of the present invention in a laminated structure in which the value ((1,000 - M 1 )) / T) is 100 or more is provided with excellent low moisture permeability even when the resin layer is thin, and has both a thin thickness and excellent low moisture permeability.

[0041] The configuration in which the value ((1,000 - M 1 )) / T) is 100 or more is preferable in that when the optical film of the present invention is used as a polarizer protection film, excellent low moisture permeability can be imparted even when the resin layer of the present invention is thin, and the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color leakage of the polarizer and further 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, more preferably 110 or more, and may be 115 or more. The upper limit value of the value ((1,000 - M 1 )) / T) is not particularly limited, but from the viewpoint of preventing the moisture inside the polarizer from escaping to the outside and preventing the occurrence of "color leakage" of the polarizer, it is preferably 500 or less, more preferably 400 or less, and may be 300 or less.

[0042] In the optical film of the present invention, from 2,000, the moisture permeability M of the optical film under the environment of a temperature of 60 ° C and a relative humidity of 90% 2 [g / m 2 ·24h] is divided by the thickness T [μm] of the resin layer, and the value ((2,000 - M 2 )) / T) is preferably 200 or more. The above numerical value "2,000" is an approximate value of the moisture permeability of the light-transmissive base material itself (light-transmissive base material having no resin layer) of the present invention under the environment of a temperature of 60 ° C and a relative humidity of 90%, and the moisture permeability M is subtracted from 2,000 2 [g / m 2 ·24h] is an approximate value of the reduced moisture permeability due to providing a resin layer on the light-transmissive base material of the present invention. Therefore, the value ((2,000 - M 2 )) / T) can be an index of the moisture permeability reduced per 1 μm of the thickness of the resin layer of the present invention under the environment of a temperature of 60 ° C and a relative humidity of 90%, and it can be said that the higher the value, the better the low moisture permeability. Therefore, the 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 provided with excellent low moisture permeability even when the resin layer is thin, and has both thinness and excellent low moisture permeability.

[0043] The configuration in which the value ((2,000 - M 2 )) / T) is 200 or more means that when the optical film of the present invention is used as a polarizer protection film, excellent low moisture permeability can be imparted even when the resin layer of the present invention is thin, and the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color leakage of the polarizer and further thinning of the resin layer of the present invention at a higher level, the product value ((2,000 - M 2 )) / T) is preferably 210 or more, more preferably 220 or more, and may be 230 or more. The upper limit value of the value ((2,000 - M 2 )) / T) is not particularly limited, but from the viewpoint of preventing the moisture inside the polarizer from escaping to the outside and preventing the occurrence of "color leakage" of the polarizer, it is preferably 1,000 or less, more preferably 800 or less, and may be 500 or less.

[0044] 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)] can also be an index of the moisture permeability of the resin layer itself of the present invention, similar to the value ((1,000 - M 1 ) / T) and the value ((2,000 - M 2 ) / T). The higher it is, the better the low moisture permeability. Therefore, the optical film of the present invention having a laminated structure with a resin layer of the present invention in which the product [((1,000 - M 1 ) / T) × ((2,000 - M 2 ) / T)] is 20,000 or more is preferably provided with excellent low moisture permeability even when the resin layer of the present invention is thin, and has both thinness and excellent low moisture permeability.

[0045] The configuration in which the product [((1,000 - M 1 ) / T) × ((2,000 - M 2 ) / T)] is 20,000 or more is preferable in that when the optical film of the present invention is used as a polarizer protection film, even when the resin layer of the present invention is thin, the occurrence of "color leakage" of the polarizer can be suppressed in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color leakage of the polarizer and further thinning of the resin layer of the present invention at a higher level, 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 value of [((1,000 - M 1 ) / T) × ((2,000 - M 2 ) / T)] is not particularly limited, but from the viewpoint of preventing the occurrence of "color leakage" of the polarizer by allowing the moisture in the polarizer to escape to the outside, it is preferably 200,000 or less, more preferably 150,000 or less, and may be 120,000 or less.

[0046] In the optical film of the present invention, from 2,700, the moisture permeability M of the optical film at a temperature of 65°C and a relative humidity of 90% 3 [g / m 2 ·24h] is subtracted from the value obtained by dividing the value obtained by subtracting the value of M by the thickness T [μm] of the resin layer ((2,700 - M 3 )) / T) is preferably 250 or more. The numerical value "2,700" is an approximate value of the moisture permeability of the light-transmissive substrate itself (light-transmissive substrate having no resin layer) of the present invention at a temperature of 65°C and a relative humidity of 90%, and the moisture permeability M is subtracted from 2,700 3 [g / m 2 ·24h] is an approximate value of the reduced moisture permeability due to providing a resin layer on the light-transmissive substrate of the present invention. Therefore, the value ((2,700 - M 3 )) / T) can be an index of the moisture permeability reduced per 1 μm of the thickness of the resin layer of the present invention at a temperature of 65°C and a relative humidity of 90%, and it can be said that the higher the value, the better the low moisture permeability. Therefore, the optical film having a resin layer of the present invention in a laminated structure in which the value ((2,700 - M 3 )) / T) is 250 or more is provided with excellent low moisture permeability even when the resin layer is thin, and has both a thin thickness and excellent low moisture permeability.

[0047] The configuration in which the value ((2,700 - M 3 )) / T) is 250 or more can impart excellent low moisture permeability even when the resin layer of the present invention is thin when the optical film of the present invention is used as a polarizer protection film, and can suppress the occurrence of "color bleeding" of the polarizer in a humid environment. From the viewpoint of achieving both suppression of the occurrence of color bleeding of the polarizer and further 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, more preferably 280 or more, and may be 300 or more. The upper limit value of the value ((2,700 - M 3 )) / T) is not particularly limited, but from the viewpoint of preventing the occurrence of "color bleeding" 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 600 or less.

[0048] Before and after the following abrasion resistance test, the change amount of the moisture permeability [g / m 2 ·24h] of the optical film in an environment of a temperature of 40°C and a relative humidity of 92% is preferably 20 or less. · Abrasion resistance test The surface of the resin layer is reciprocated 10 times under the conditions of a load of 3.92 N and a moving speed of 100 mm / second using steel wool. Generally, the moisture permeability after the above abrasion resistance test tends to increase compared to the moisture permeability before the test, but the change amount also includes the case where the moisture permeability after the abrasion resistance test decreases compared to the moisture permeability before the test. Therefore, the change amount is, for example, the absolute value of the value obtained by subtracting the moisture permeability before the test from the moisture permeability after the abrasion resistance test.

[0049] The resin layer of the present invention imparts excellent low moisture permeability to the optical film of the present invention. Generally, the moisture permeability tends to increase as the film thickness increases, and the moisture permeability tends to decrease as the film thickness decreases. In addition, the resin layer of the present invention imparts excellent abrasion resistance to the optical film of the present invention. Generally, the abrasion resistance tends to increase as the film thickness increases, and the abrasion resistance tends to decrease as the film thickness decreases. Therefore, the optical film of the present invention having a laminated structure of the resin layer of the present invention such that the change rate is 20 or less is provided with excellent low moisture permeability and abrasion resistance even when the resin layer of the present invention becomes thinner, and has both a thin thickness and excellent low moisture permeability and durability.

[0050] The configuration in which the change rate is 20 or less is preferable in that when the optical film of the present invention is used as a polarizer protection film, even when the resin layer of the present invention is thin, the surface hardness and scratch resistance are less likely to decrease, preventing a decrease in moisture permeability due to scratches and suppressing the occurrence of "color bleeding" of the polarizer. From the viewpoint of achieving both suppression of the occurrence of color bleeding of the polarizer and higher scratch resistance of the resin layer of the present invention, the change amount is preferably 18 or less, more preferably 15 or less, and may be 12 or less, or 10 or less. The lower limit value of the change amount is not particularly limited, and it is most preferable that there is no change, that is, 0, but in terms of suppressing the occurrence of "color bleeding" of the polarizer, for example, it may be about 0.1 or more to 0.5 or more.

[0051] The moisture permeability M in the optical film of the present invention 1 , M 2 , and M 3 , and the thickness T of the resin layer and the moisture permeability M 1 , M 2 , or M 3 and the product with, the value ((1,000 - M 1 ) / T), the value ((2,000 - M 2 ) / T), the value ((2,700 - M 3 ) / T), their product, and the change amount of the moisture permeability before and after the scratch resistance test can be specifically measured according to a known method, for example, in accordance with JIS Z0208. The moisture permeability M in the optical film of the present invention 1 , M 2 , and M 3 , and the thickness T of the resin layer and the moisture permeability M 1 , M 2 , or M 3 and the product with, the value ((1,000 - M 1 ) / T), the value ((2,000 - M 2 ) / T), the value ((2,700 - M 3 ) / T), their product, and the change amount of the 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 substrate of the present invention, the above configuration of the resin layer of the present invention, and the like.

[0052] 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 determined in accordance with 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 constituting the light-transmissive substrate of the present invention, the type and thickness of the resin constituting the resin layer of the present invention, and the like.

[0053] 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 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 and thickness of the resin constituting the light-transmissive substrate of the present invention, the above composition and thickness of the resin layer constituting the present invention, and the like.

[0054] The thickness of the optical film of the present invention is not particularly limited. For example, considering workability such as thin layer properties, strength, and handleability, the range of 1 to 500 μm is preferable, more preferably the range of 10 to 300 μm, and optimally the range of 20 to 200 μm.

[0055] <Light-transmissive substrate> Examples of the material constituting the light-transmissive 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 polymers (COP) (for example, trade name "ARTON" (manufactured by JSR Corporation), trade name "ZEONOR" (manufactured by Zeon Corporation), etc.), polycarbonate resins, polysulfone resins, polyarylate resins, polyimide resins, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymers, and other plastic materials. From the viewpoints of optical uniformity, smooth surface, and good secondary processability in manufacturing a polarizing plate, cellulose resins, acrylic resins, polyester resins, and cyclic olefin polymers (COP) are preferred, and cellulose resins are particularly preferred. These plastic materials can be used alone or in combination of two or more.

[0056] The haze of the light-transmissive 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 determined in accordance with JIS K 7136 (2000). The haze of the light-transmissive substrate of the present invention can be adjusted by the type and thickness of the resin constituting the light-transmissive substrate of the present invention.

[0057] The total light transmittance in the visible light wavelength region of the light-transmissive substrate of the present invention is not particularly limited, but is preferably 85% or more, more preferably 88% or more. The visible light wavelength region can be determined in accordance with JIS K 7361-1. The total light transmittance of the light-transmissive substrate of the present invention can be adjusted by the type and thickness of the resin constituting the light-transmissive substrate of the present invention.

[0058] The thickness of the light-transmissive substrate of the present invention is not particularly limited. However, for example, considering workability such as thin-layer properties, strength, and handleability, and thin-layer properties, etc., a range of 1 to 500 μm is preferable, more preferably a range of 10 to 300 μm, and optimally a range of 20 to 200 μm.

[0059] The refractive index of the light-transmissive substrate of the present invention is not particularly limited. However, for example, it is in the range of 1.30 to 1.80, preferably in the range of 1.40 to 1.70. Further, on the surface of the light-transmissive substrate of the present invention (the surface on which the resin layer is formed and / or the opposite surface), known and commonly used surface treatments such as physical treatments such as corona discharge treatment and plasma treatment, and chemical treatments such as undercoat treatment may be appropriately performed.

[0060] <Resin layer> The resin layer of the present invention is laminated on one surface of the light-transmissive substrate of the present invention and imparts excellent low moisture permeability to the optical film of the present invention. Further, 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 in a laminated structure can be suitably used as a polarizing plate protective film.

[0061] The surface of the resin layer of the present invention is preferably not scratched when a scratch resistance test is performed under the conditions of a load of 0.98 N, a moving speed of 100 mm / second, and 10 reciprocations using steel wool. That is, since the optical film of the present invention is coated with the resin layer of the present invention having excellent scratch resistance, it is less likely to be scratched in the manufacturing process even when made thin, and can provide a polarizing plate having excellent durability when used as a polarizing plate protective film. 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.

[0062] The resin layer of the present invention is formed of a cured product of 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. The 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".

[0063] The cycloaliphatic hydrocarbon group possessed by the polymerizable compound A has a highly hydrophobic chemical structure, which can impart excellent low moisture permeability to the resin layer. On the other hand, due to its bulky nature, the structure tends to be sparse, and the surface hardness and scratch resistance are likely to decrease. On the other hand, the polymerizable compound B is polyfunctional, and by increasing the crosslinking density, the scratch resistance of the resin layer can be enhanced. Therefore, the resin layer of the present invention formed of a cured product of a curable composition containing the polymerizable compound A and the polymerizable compound B, with the ratio thereof (polymerizable compound A / polymerizable compound B) being 95 / 5 to 10 / 90, can achieve both excellent low moisture permeability and 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. Further, 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.

[0064] From the viewpoint of imparting excellent low moisture permeability to the resin layer, the ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A / polymerizable compound B) is preferably 10 / 90 or more, more preferably 15 / 85 or more, or may be 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 more, 65 / 35 or more, 70 / 30 or more, 75 / 25 or more, 80 / 20 or more, 85 / 15 or more, or 90 / 10 or more. On the other hand, from the viewpoints of achieving both low moisture permeability and scratch resistance at a higher level in the resin layer and appropriately releasing moisture in the polarizing plate to the outside to prevent the occurrence of "color bleeding" of the polarizer, it may be 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.

[0065] Examples of the unsaturated double bond group of the polymerizable compound A include a (meth)acryloyl group, a vinyl group, a styryl group, an allyl group, etc. Among them, a (meth)acryloyl group is preferable. Particularly preferable is a compound containing two or more (meth)acryloyl groups in one molecule as described below.

[0066] The number of "unsaturated double bond groups" in the polymerizable compound A in the molecule is not particularly limited as long as it is 1 or more. However, in terms of imparting excellent low moisture permeability and scratch resistance to the optical film of the present invention, it is preferable to have two or more unsaturated double bond groups, more preferably three or more, and even more preferably four or more. The upper limit of the number of "unsaturated double bond groups" of the polymerizable compound A is not particularly limited, but it may be 10 or less, 9 or less, or 8 or less.

[0067] The "cyclic aliphatic hydrocarbon group" in 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 even more preferably a group derived from an alicyclic compound having 12 or more carbon atoms. As the cyclic aliphatic hydrocarbon group, particularly preferably, it is a group derived from a polycyclic compound such as a bicyclic or tricyclic compound.

[0068] As the cyclic aliphatic hydrocarbon group (including the linking group), a group represented by any of the following general formulas (I) to (V) is preferable, a group represented by the following general formulas (I), (II), or (IV) is more preferable, and a group represented by the following general formula (I) is even more preferable.

Chemical formula

[0069] In the general formula (I), L and L' each independently represent a divalent or higher linking group. n represents an integer of 1 to 3.

Chemical formula

[0070] In general formula (II), L and L' each independently represent a divalent or higher linking group. n represents an integer of 1 to 2. [Chemical formula]

[0071] In general formula (III), L and L' each independently represent a divalent or higher linking group. n represents an integer of 1 to 2. [Chemical formula]

[0072] In general formula (IV), L and L' each independently represent a divalent or higher linking group, and L" represents a hydrogen atom or a divalent or higher linking group. [Chemical formula]

[0073] In general formula (V), L and L' each independently represent a divalent or higher linking group.

[0074] Specific examples of the cycloaliphatic hydrocarbon group include monovalent to trivalent groups derived from norbornane, tricyclodecane, tetracyclododecane, pentacyclopentadecane, adamantane, diamantane, etc.

[0075] The polymerizable compound A containing a group represented by any of the above general formulas (I) to (V) as a cycloaliphatic hydrocarbon group has a polymerizable functional group via the linking groups represented by L, L', and L". Examples of the linking group include a single bond, an optionally substituted alkylene group having 1 to 6 carbon atoms, an amide group optionally disubstituted at the N-position, a carbamoyl group optionally substituted at the N-position, an ester group, an oxycarbonyl group, an ether group, etc., and groups obtained by combining these.

[0076] The polymerizable compound A can be easily synthesized, for example, by a one-step or two-step reaction of a polyol such as a diol or triol having the above cyclic aliphatic hydrocarbon group with a carboxylic acid, carboxylic acid derivative, epoxy derivative, isocyanate derivative, etc. of a compound having a (meth)acryloyl group, vinyl group, styryl group, allyl group, etc. Preferably, it can be synthesized by reacting with a polyol having the above cyclic aliphatic hydrocarbon group using (meth)acrylic acid, (meth)acryloyl chloride, (meth)acrylic anhydride, glycidyl (meth)acrylate, 1,1-bis(acryloxymethyl)ethyl isocyanate, etc.

[0077] Hereinafter, preferred specific examples of the polymerizable compound A are shown, but the present invention is not limited thereto.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0078] The content of the polymerizable compound A in the curable composition of the present invention is not particularly limited. However, from the viewpoint of imparting excellent low moisture permeability to the resin layer of the present invention, it is preferably 10% by weight or more, more preferably 15% by weight or more, or may be 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 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, 85% by weight or more, or 90% by weight or more based on 100% by weight of the non-volatile solid content of the curable composition of the present invention. On the other hand, from the viewpoint of achieving both low moisture permeability and high scratch resistance at a higher level in the resin layer of the present invention, it 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, 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% by weight or less, or 10% by weight or less.

[0079] As the polymerizable functional group of the polymerizable compound B, an unsaturated double bond group such as a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group is preferable. Among them, a (meth)acryloyl group is preferable. Particularly preferable examples include compounds containing two or more (meth)acryloyl groups in one molecule as described below.

[0080] In addition to the polymerizable compound B, it is a polyfunctional polymerizable compound other than the polymerizable compound A, that is, a compound having no alicyclic hydrocarbon group in the molecule and having two or more polymerizable functional groups. The polymerizable compound A tends to have low scratch resistance due to the three-dimensional structure of the alicyclic hydrocarbon group in the molecule. It is considered that when the curable composition of the present invention contains the polymerizable compound B in addition to the polymerizable compound A, the crosslink density increases and the scratch resistance is improved.

[0081] The number of "polymerizable functional groups" possessed by the polymerizable compound B is not particularly limited as long as it is 2 or more. However, from the viewpoint of imparting excellent scratch resistance to the optical film of the present invention, it preferably has 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" possessed by the polymerizable compound B is not particularly limited, but it may be 30 or less, 25 or less, or 20 or less. In particular, the number of "polymerizable functional groups" is preferably 5 to 10, and more preferably 8 to 10.

[0082] Examples of the polymerizable compound B include a monomer having no alicyclic hydrocarbon group in the molecule and having 2 or more polymerizable functional groups (hereinafter sometimes referred to as "polymerizable monomer B"), and an oligomer having no alicyclic hydrocarbon group in the molecule and having 2 or more polymerizable functional groups (hereinafter sometimes referred to as "polymerizable oligomer B"). The curable composition of the present invention may contain only a polymerizable monomer as the polymerizable compound B, may contain only a polymerizable oligomer B, or may contain both a polymerizable monomer B and a polymerizable oligomer B. From the viewpoint of forming a high crosslink density, it is preferable to contain at least a polymerizable oligomer B.

[0083] 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, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol (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.

[0084] 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 obtained by adding two or more (meth)acryloyl groups as functional groups to the urethane skeleton, polyester (meth)acrylate obtained by adding two or more (meth)acryloyl groups as functional groups to the polyester skeleton, epoxy (meth)acrylate obtained by adding two or more (meth)acryloyl groups as functional groups to the epoxy skeleton, and the like. From the viewpoint of forming a high crosslink density, it is preferably at least containing urethane (meth)acrylate, and particularly preferably 5-10 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 oligomers B.

[0085] Urethane (meth)acrylate can be obtained, for example, by reacting a polyol, an isocyanate, and a hydroxy (meth)acrylate. As the polyol constituting the urethane (meth) acrylate, known polyols can be used without limitation. From the viewpoint of improving the crosslinking density, polyols having three or more (preferably four or more, more preferably five or more, still more preferably six or more) hydroxyl groups are preferred, and examples include trimethylolpropane, ethoxylated isocyanuric acid, pentaerythritol, dipentaerythritol, tripentaerythritol, and tetrapentaerythritol. These polyols may be used alone or in combination of two or more.

[0086] As the isocyanate constituting the urethane (meth) acrylate, polyisocyanates composed of linear saturated hydrocarbons, cyclic saturated hydrocarbons, and aromatic hydrocarbons can be used. Examples of such polyisocyanates include linear saturated hydrocarbon isocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate; cyclic saturated hydrocarbon isocyanates such as isophorone diisocyanate, dicyclohexylmethane diisocyanate, methylene bis(4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated toluene diisocyanate; and aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 1,3-xylylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diisocyanate, 6-isopropyl-1,3-phenyl diisocyanate, and 1,5-naphthalene diisocyanate. Preferred specific examples include isophorone diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. These polyisocyanates may be used alone or in combination of two or more.

[0087] Examples of the hydroxy (meth)acrylate that constitutes the urethane (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and the like. These hydroxy (meth)acrylates may be used alone or in combination of two or more.

[0088] Examples of the urethane (meth)acrylate include Art Resin UN series manufactured by Negami Kogyo Co., Ltd., NK Oligo U series manufactured by Shin-Nakamura Chemical Co., Ltd., and Purple Light UV series manufactured by Mitsubishi Chemical Corporation.

[0089] The polyester (meth)acrylate is obtained, for example, by reacting (meth)acrylic acid with the terminal hydroxyl groups of a polyester obtained by polymerizing a polyol and a polyvalent carboxylic acid. Specific examples of the polyester (meth)acrylate include Aronix M-6000, Aronix M-7000, Aronix M-8000, and Aronix M-9000 manufactured by Toagosei Co., Ltd.

[0090] The epoxy (meth)acrylate is obtained, for example, by reacting (meth)acrylic acid with an epoxy resin. Specific examples of the epoxy (meth)acrylate include Lipoxy SP and Lipoxy VR manufactured by Showa Highpolymer Co., Ltd., and Epoxy Ester series manufactured by Kyoeisha Chemical Co., Ltd.

[0091] 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 700 or more. Further, 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, and still more preferably 5,000 or less. 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 the apparatus, and using two TSKgel GMH-H(20) connected in series as the columns, and using tetrahydrofuran as the solvent, the measurement of the weight average molecular weight can be carried out under the condition of a flow rate of 0.5 mL / min.

[0092] 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, based on 100% by weight of the non-volatile solid content of the curable composition of the present invention, 5% by weight or more is preferable, 10% by weight or more is more preferable, 15% by weight or more is still more preferable, or it may be 20% by weight or more, 25% by weight or more, 30% by weight or more, 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, 85% by weight or more, or 90% by weight or more. On the other hand, from the viewpoint of achieving both low moisture permeability and higher-level scratch resistance in the resin layer of the present invention, it may be 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% by weight or less, 10% by weight or less, or 5% by weight or less.

[0093] The curable composition of the present invention preferably contains a polymerization initiator, and a photoinitiator is preferably used as the polymerization initiator. Examples of the photoinitiator include benzophenone-based compounds such as benzyl, benzophenone, benzoyl benzoic acid, 3,3'-dimethyl-4-methoxybenzophenone; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexyl phenyl ketone; acetophenone-based compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropan-1; benzoin alkyl ether-based compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, anisoin methyl ether; aromatic ketal-based compounds such as benzyldimethyl ketal; aromatic sulfonyl chloride-based compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime-based compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone-based compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphine oxides; acylphosphonates and the like. These polymerization initiators may be used alone or in combination of two or more.

[0094] The content of the photoinitiator in the curable composition of the present invention is not particularly limited. However, from the viewpoint of sufficiently obtaining low moisture permeability and scratch resistance of the resin layer of the present invention, it is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and still more preferably 0.2 parts by weight or more with respect to 100 parts by weight of the polymerizable compound (the total of polymerizable compound A and polymerizable compound B). Further, the content of the photoinitiator in the curable composition of the present invention 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 (the total of polymerizable compound A and polymerizable compound B) from the viewpoint of suppressing the problem that the curable composition of the present invention does not sufficiently cure due to excessive radiation absorption by the photoinitiator.

[0095] Various leveling agents can be added to the curable composition of the present invention. As the leveling agent, for the purpose of preventing coating unevenness (uniformizing the coating surface), for example, a fluorine-based or silicone-based leveling agent can be used. When antifouling property is required on the surface of the resin layer of the present invention, a leveling agent can also be appropriately blended. 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 (the total of polymerizable compound A and polymerizable compound B).

[0096] The curable composition of the present invention can 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), the drying property during coating, etc. 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, methyl ethyl carbonate, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, 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-butoxyethanol, 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. These can be used alone or in combination of two or more kinds.

[0097] The curable composition of the present invention may further contain any appropriate additives such as a plasticizer, a surfactant, an antioxidant, an ultraviolet absorber, a thixotropy agent, an antistatic agent, etc., as long as the effects of the present invention are not impaired, if necessary.

[0098] 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 made thin, excellent low moisture permeability and scratch resistance 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, from the viewpoint of making the polarizing plate thinner, the film thickness of the resin layer is preferably 4.5 μm or less, more preferably 4 μm or less, and may be 3.2 μm or less, or 3 μm or less. From the viewpoint of achieving both low moisture permeability and scratch resistance at a higher level, the lower limit value 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 may be 2 μm or more. The resin layer of the present invention may be a single layer or may be provided in 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 each layer constituting the plurality of layers.

[0099] The resin layer of the present invention can be formed by mixing a polymerizable compound A and a polymerizable compound B, and, if necessary, a polymerizable compound other than the polymerizable compound A and the polymerizable compound B, a photopolymerization initiator, a leveling agent, a solvent, and other additives to prepare a coating solution (the curable composition of the present invention), applying the coating solution to one surface of a light-transmissive substrate, drying it, and curing the coating film.

[0100] The solid content concentration of the coating solution is preferably 1% by weight to 70% by weight, more preferably 2% by weight to 50% by weight, and even more preferably 5% by weight to 40% by weight.

[0101] Examples of the coating method of the coating solution include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a die coating method, an extrusion coating method, a bar coating method, and the like.

[0102] The 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 light using a light source that emits light of a required 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 2~1000 mJ / cm 2 Light of 2 can be used. Further, heating may be performed during the photocuring treatment. Examples of the light include ionizing radiation such as α-rays, β-rays, γ-rays, neutron rays, and electron beams, and ultraviolet rays, with ultraviolet rays being particularly preferred. Further, the irradiation time, irradiation method, etc. are not particularly limited, as long as the photopolymerization initiator can be activated to cause the reaction of the polymerizable compound.

[0103] <Polarizing plate> The polarizing plate of the present invention has a laminated structure in which a polarizer is disposed on the side opposite to the resin layer of the optical film of the present invention. In FIG. 2, the polarizing plate 20 has a laminated structure in which a polarizer 3 is disposed on the side opposite to the resin layer 1 of the optical film 10. 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 when the resin layer 1 is thin, and quality deterioration such as color bleeding of the polarizer 3 is less likely to occur. In the present embodiment, a second light transmissive substrate 4 and an adhesive layer 5 are further laminated in this order on the side of the polarizer 3 opposite to the optical film 10.

[0104] The polarizer 3 is an element that transmits only light with a polarization plane in a certain direction, and known polarizers 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 a dichroic dye.

[0105] 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 a durability treatment with a boron compound); or a film obtained by dyeing a polyvinyl alcohol-based film with iodine or a dichroic dye and then uniaxially stretching it (preferably a film further subjected to a durability treatment with a boron compound). The absorption axis of the polarizer is parallel to the stretching direction of the film.

[0106] 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.

[0107] The second light-transmissive substrate 4 protects the side opposite to the optical film 10 of the polarizer 3 (polarizing plate protective film), and the same glass, plastic film, etc. as the light-transmissive substrate of the present invention can be used. 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 different materials. The light-transmissive substrate 4 may have the resin layer 1 laminated thereon or may not have the resin layer 1. Further, the light-transmissive substrate 4 may be composed of a single layer or may have a laminated structure of two or more layers that are the same or different.

[0108] Also, the light-transmissive substrate 4 is preferably an optical compensation film (retardation film) having an optical compensation layer including an optically anisotropic layer. The optical compensation film can improve, for example, the viewing angle characteristics of a liquid crystal display screen. As the optical compensation film, known ones can be used without limitation. For example, the retardation film described in JP-A-2014-194484 may be used.

[0109] 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.

[0110] The adhesive layer 5 is formed of any suitable adhesive. Examples of materials constituting the adhesive layer 5 include materials based on polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine-based polymers, rubber-based polymers, isocyanate-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, vinyl-based polymers, latex-based polymers, and water-based polyesters. Among them, materials based on acrylic polymers and / or rubber-based polymers are preferred from the viewpoint of low moisture permeability. The adhesive layer 5 may contain a single base polymer or two or more base polymers.

[0111] 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.

[0112] The polarizing plate 20 can be obtained by bonding the polarizer 1 and the optical film 1 through an adhesive. Also, the polarizer 1 and the light-transmissive substrate 4 can be bonded through an adhesive. The adhesive used for bonding may be a fully saponified polyvinyl alcohol aqueous solution (water paste), or may be performed using an active energy ray-curable adhesive.

[0113] The adhesive layer 5 can be formed by applying an adhesive composition containing a base polymer constituting the adhesive to the light-transmissive substrate 4, drying, and curing as necessary. Alternatively, the adhesive layer 5 may be formed on a separator in the same manner and then attached and transferred to the light-transmissive substrate 4.

[0114] Layers other than the polarizing plate 20, the optical film 10, the polarizing plate 3, the light-transmissive substrate 4, and the adhesive layer 5 (for example, a surface protection 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 by a separator, and the surface of the resin layer 1 of the optical film 10 may be protected by a surface protection film.

[0115] The thickness of the polarizing plate 20 (total thickness including the light transmissive substrate 4 and the adhesive layer 5) is preferably 50 to 100 μm, and more preferably 60 to 75 μm from the viewpoint of thinning the polarizing plate 20.

[0116] <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 the laminated structure, even if the resin layer 1 is thin, it has excellent low moisture permeability and scratch resistance, and quality deterioration such as color bleeding of the polarizer 3 is less likely to occur. Therefore, the image display device of the present invention is less likely to cause color bleeding or the like of the polarizing plate in a humid environment and has excellent durability even if it is thin. In FIG. 3, in the image display device 30, an image display panel 6 is laminated on the adhesive layer 5 of the polarizing plate 20. In the present embodiment, an adhesive layer 7 and an optical member 8 are laminated on the resin layer 1 in this order.

[0117] The image display panel 6 is not particularly limited, and examples thereof include a liquid crystal image display panel and a self-luminous image display panel (for example, an organic EL (electroluminescence) image display panel, an LED image display panel).

[0118] The image display panel 6 is formed by alternately arranging RGB elements, and in order to improve the contrast, it is preferable that the space between the RGB elements is filled with a black matrix (BM).

[0119] As the adhesive layer 7, a material containing the same base polymer as that exemplified in the adhesive layer 5 can be used. Among them, a material based on an acrylic polymer and / or a rubber-based polymer is preferable from the viewpoint of low moisture permeability. The adhesive layer 7 may contain a single base polymer or two or more base polymers. The adhesive layer 7 may be composed of the same material as the adhesive layer 5 or a different material.

[0120] The optical member 8 can be made of the same glass, plastic film, etc. as the light-transmissive base material of the present invention. Acrylic resins, polyester resins, and cyclic olefin polymers (COP) are preferred, and polyester resins are particularly preferred. When the optical member 8 is located on the outermost surface on the viewing side of the image display device 30, it functions as a cover member.

[0121] The image display device 30 may include optical members other than the optical film 10, polarizing plate 3, light-transmissive base material 4, adhesive layer 5, image display panel 6, adhesive layer 7, and optical member 8 on the surface or between arbitrary layers. The optical members are not particularly limited, and examples include polarizing plates other than the polarizing plate 3, retardation plates, antireflection films, viewing angle adjustment films, optical compensation films, etc. The optical members shall also include members (such as design films, decorative films, and surface protection plates) that play a role in decoration and protection while maintaining the visibility of the image display device and input device.

[0122] The image display device 30 can be manufactured by laminating an optical film in which the image display panel 6, polarizing plate 20, optical member 8, and adhesive layer 7 are laminated. Specifically, it can be carried out by laminating under heating and / or pressure. After laminating under heating and / or pressure, it may be cured by irradiating active energy rays. The irradiation of active energy rays can be carried out in the same manner as the formation of the resin layer of the present invention.

Examples

[0123] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these examples.

[0124] Example 1 (Preparation of Coating Liquid for Resin Layer Formation) As the resin contained in the resin layer, 90 parts by weight (in terms of solid content) of an ultraviolet-curable acrylate resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-DCP", solid content 100%) and 10 parts by weight (in terms of solid content) of an ultraviolet-curable acrylate resin (manufactured by Mitsubishi Chemical Corporation, trade name "UV-1700TL", solid content 80%) were prepared. Per 100 parts by weight of the resin solid content of the resin, 5 parts by weight of a photoinitiator (manufactured by BASF, trade name "OMNIRAD907") and 0.2 parts by weight of a leveling agent (manufactured by Kyoeisha Chemical Co., Ltd., trade name "LE-303", solid content 40%) were mixed. This mixture was diluted with a MIBK / cyclopentanone mixed solvent (weight ratio 60 / 40) so that the solid content concentration became 30% to prepare a coating liquid for forming a resin layer.

[0125] (Preparation of optical film) As a light-transmissive substrate, a transparent plastic film substrate (TAC, manufactured by Fuji Film Co., Ltd., trade name "TJ25UL") was prepared. On one side of the transparent plastic film substrate, the coating liquid for forming a resin layer prepared above was used to form a coating film using a bar coater #7. Then, the transparent plastic film substrate on which this coating film was formed was conveyed to a drying process. In the drying process, the coating film was dried by heating at 60°C for 1 minute. Thereafter, ultraviolet rays with an integrated light amount of 220 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the coating film and form a resin layer with a thickness of 2.5 μm, and the optical film 1 of Example 1 was obtained. The details of the resin used in Example 1 are as follows. · A-DCP: tricyclodecane dimethanol dimethacrylate · UV-1700TL: 10-functional urethane acrylate

[0126] Example 2 The optical film 2 of Example 2 was obtained in the same manner as in Example 1, except that 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 as the resin contained in the resin layer.

[0127] Example 3 As the resin contained in the resin layer, Example 3's optical film 3 was obtained in the same manner as in Example 1, except that 50 parts by weight (in terms of solid content) of A-DCP and 50 parts by weight (in terms of solid content) of UV-1700TL were blended.

[0128] Comparative Example 1 As the resin contained in the resin layer, Comparative Example 1's optical film 4 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.

[0129] Comparative Example 2 As the resin contained in the resin layer, Comparative Example 2's optical film 5 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.

[0130] (Evaluation) Using the optical films obtained in the above Examples and Comparative Examples, the following evaluations were conducted. The evaluation methods are shown below. The results are shown in Table 1.

[0131] (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 at 5 points with respect to the width, and the average value of the 5 film thicknesses was taken as the total thickness. Using the same measurement method, the film thickness of the light-transmissive substrates used in the Examples and Comparative Examples was measured, and the average value of the 5 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.

[0132] (2) Moisture permeability measurement In accordance with JIS Z0208, the moisture permeability of the optical films of the Examples and Comparative Examples was measured at 40 °C and a relative humidity of 92%.

[0133] (3) Evaluation of color leakage of polarizers After storing the optical films of the Examples and Comparative Examples in an environment of 60 °C and 90% for 120 hours, when observing the film with the illuminance of the backlight set to 8000 candela in a dark room, if color leakage such as unevenness or streaks was visually recognized, it was determined that there was color leakage of the polarizer.

[0134] (4) Measurement of Abrasion Resistance The optical films of the examples and comparative examples were cut into pieces with a size of 5 cm × 15 cm, and #0000 steel wool was brought into contact with the surface of the resin layer so that the diameter was 2.5 cm and the contact area was 6.25×π cm 2 A load of 100 gf (0.98 N) was applied to the steel wool, and the surface of the resin layer was rubbed 10 times back and forth at a moving speed of 100 mm / s with respect to the long side direction of the film. The presence or absence of scratches was visually determined in the central 5 cm × 5 cm portion of the film after the test under the environments of a fluorescent lamp and an LED light source.

[0135] [Table 1]

[0136] (5) Measurement of Moisture Permeability The moisture permeability of the optical films of Examples 2 and 3 was measured under the temperature and humidity conditions for the test of 60°C, 90% relative humidity, or 65°C, 90% relative humidity, in the same manner as 40°C, 92%. The thickness of the resin layer [μm], the product of the moisture permeability of the optical film [g / m 2 ·24 h] in the environment of 40°C and 92% relative humidity (1), the thickness of the resin layer [μm] and the moisture permeability of the optical film [g / m 2 ·24 h] in the environment of 60°C and 90% relative humidity (2), the thickness of the resin layer [μm] and the moisture permeability of the optical film [g / m 2 ·24 h] in the environment of 65°C and 90% relative humidity (3), the product of product (1) and product (2) ((1)×(2)), 1,000 minus the moisture permeability of the optical film [g / m 2 ·24 h] in the environment of 40°C and 92% relative humidity divided by the thickness of the resin layer [μm] (4), 2,000 minus the moisture permeability of the optical film [g / m 2 ·24 h] in the environment of 60°C and 90% relative humidity divided by the thickness of the resin layer [μm] (5), 2,700 minus the moisture permeability of the optical film [g / m 2The value obtained by dividing the value obtained by subtracting [·24 h] by the thickness [μm] of the resin layer (6), and the product ((4) × (5)) of the value (4) and the value (5) are shown in Table 2.

Table 2

[0137] (6) Measurement of water vapor transmission rate after abrasion resistance test The optical films of Examples 2 and 3 were cut out into a size of 5 cm × 15 cm, and on the surface of the resin layer, #0000 steel wool with a diameter of 2.5 cm and a contact area of 6.25×π cm 2 was brought into contact. A load of 400 gf (3.92 N) was applied to the steel wool, and after the surface of the resin layer was rubbed 10 times back and forth at a moving speed of 100 mm / s in the long side direction of the film, in the same manner as above, the water vapor transmission rate at a temperature of 40 °C and a relative humidity of 92% was measured. The change amount of the water vapor transmission rate after the abrasion resistance test was 9 g / m 2 ·24 h for Example 2 and 1 g / m 2 ·24 h for Example 3.

[0138] The 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-transmissive substrate, wherein the resin layer is formed of a cured product of 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, and the ratio (polymerizable compound A / polymerizable compound B) of the polymerizable compound A to the polymerizable compound B is 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. [Supplementary Note 4] The optical film according to any one of Supplementary Notes 1 to 3, wherein the light-transmissive substrate contains at least one selected from the group consisting of a cellulose-based resin, a polyester-based resin, an acrylic-based resin, and a cyclic olefin-based polymer. [Supplementary Note 5] A polarizing plate in which a polarizer is disposed on the side opposite to the resin layer of the optical film according to any one of Supplementary Notes 1 to 4. [Supplementary Note 6] An image display device having the polarizing plate according to Supplementary Note 5. [Supplementary Note 7] The image display device according to Supplementary Note 6, wherein an adhesive layer and an optical member are laminated in this order on the resin layer.

Explanation of Reference Numerals

[0139] 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

1. An optical film in which a resin layer is laminated on one surface of a light-transmissive substrate, The resin layer is formed of a cured product of 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. The polymerizable compound B is a 5- to 10-functional urethane (meth)acrylate which is a reaction product of a polyol, an isocyanate, and a hydroxy (meth)acrylate, and the polyol is at least one selected from the group consisting of trimethylolpropane, ethoxylated isocyanuric acid, pentaerythritol, dipentaerythritol, tripentaerythritol, and tetraerythritol. A polarizing plate protective film in which the ratio of the polymerizable compound A to the polymerizable compound B (polymerizable compound A / polymerizable compound B) is 95 / 5 to 65 / 35.

2. The polarizing plate protective film according to claim 1, wherein the film thickness of the resin layer is 0.5 to 5 μm.

3. The polarizing plate protective film according to claim 1 or 2, wherein the light-transmissive substrate contains at least one selected from the group consisting of a cellulose-based resin, a polyester-based resin, an acrylic-based resin, and a cyclic olefin-based polymer.

4. A polarizing plate in which a polarizer is disposed on the side opposite to the resin layer of the polarizing plate protective film according to any one of claims 1 to 3.

5. An image display device having the polarizing plate according to claim 4.

6. The image display device according to claim 5, wherein an adhesive layer and an optical member are laminated in this order on the resin layer.

Images