Optical thin films

Abstract

The purpose of this invention is to provide an optical film that combines excellent low moisture permeability and excellent scratch resistance, and is suitable for use as a protective film for polarizing plates. The optical thin film 10 of the present invention has a laminated structure in which a resin layer 1 is formed on one area layer of a light-transmitting substrate 2. The resin layer 1 is formed from a cured product of a curable composition, which includes: a polymeric compound A having cyclic aliphatic hydrocarbon groups and unsaturated double bonds, and a multifunctional polymeric compound B other than polymeric compound A. The ratio of polymeric compound A to polymeric compound B (polymeric compound A / polymeric compound B) is 95 / 5 to 10 / 90.

Description

Technical Field

[0001] This invention relates to an optical thin film. More specifically, it relates to an optical thin film suitable for use as a protective film for polarizing plates. Prior Technology

[0002] In image display devices (such as liquid crystal displays and organic EL displays), due to their image formation methods, a polarizing plate is usually disposed on at least one side of the display unit. The polarizing plate has the function of allowing light with a fixed polarization plane to pass through only, and the performance of the image display device is greatly affected by the performance of the polarizing plate. The polarizing plate is generally composed of a polarizing element and a transparent protective film (polarizing plate protective film) attached to at least one side of the polarizing element, wherein the polarizing element is composed of a polyvinyl alcohol film or the like that into which iodine or dye has been adsorbed and oriented (e.g., Patent Document 1). Previous technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2000-338329 Summary of the Invention

[0004] The problem the invention aims to solve In recent years, the market for mobile devices such as smartphones and tablets has expanded, increasing the demand for thinner image display devices. This has led to a need for thinner components, such as polarizer protective films. However, there is a problem that as the thickness of the polarizer protective film decreases, the protective function for the polarizer is reduced.

[0005] For example, if the protective film of the polarizing plate becomes thinner, the permeability to moisture (moisture permeability) will increase, and the polarizing performance of the polarizing element will disappear in a humid environment, resulting in a phenomenon known as "fading".

[0006] Furthermore, if the protective film for polarizing plates becomes thinner, it will lead to problems such as reduced surface hardness or scratch resistance, increased susceptibility to damage during manufacturing processes, and reduced moisture permeability, all of which degrade the performance of the polarizing plate. Therefore, optical films used as protective films for polarizing plates must also have excellent scratch resistance.

[0007] To improve the low moisture permeability of the polarizer protective film, the resin constituting the film must be made of a highly hydrophobic structure. However, highly hydrophobic chemical structures are generally bulky and therefore tend to be loose, which can lead to a decrease in surface hardness or scratch resistance. In other words, low moisture permeability and scratch resistance are trade-offs and are usually difficult to achieve simultaneously.

[0008] The present invention was conceived based on the circumstances described above. The purpose of the present invention is to provide an optical film that, even when thinned, can still maintain excellent low moisture permeability and scratch resistance, and is suitable for polarizer protective films.

[0009] The means to solve the problem That is, the first aspect of the present invention provides an optical film having a resin layer on one of the area layers of a light-transmitting substrate. The aforementioned resin layer imparts excellent low moisture permeability to the optical film of the first aspect of the present invention. Furthermore, the aforementioned 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 aforementioned resin layer in a laminated structure is suitable as a protective film for polarizing plates.

[0010] In the optical thin film of the first aspect of the present invention, the aforementioned resin layer is formed by curing a curable composition, which comprises: a polymeric compound A having cyclic aliphatic hydrocarbon groups and unsaturated double bonds, and a polymeric compound B other than polymeric compound A. This configuration preferably imparts excellent low moisture permeability to the optical thin film of the first aspect of the present invention. Furthermore, it also preferably imparts excellent scratch resistance to the optical thin film of the first aspect of the present invention.

[0011] In the optical thin film of the first aspect of the present invention, the ratio of the aforementioned polymeric compound A to polymeric compound B (polymeric compound A / polymeric compound B) is 95 / 5 to 10 / 90. The aforementioned polymeric compound A has a highly hydrophobic chemical structure with cyclic aliphatic hydrocarbon groups, which can impart excellent low moisture permeability to the aforementioned resin layer. However, its large volume makes its structure prone to loosening, thus easily reducing surface hardness or scratch resistance. On the other hand, polymeric compound B is multifunctional; by increasing the crosslinking density, the scratch resistance of the aforementioned resin layer can be improved. Therefore, the optical thin film of the first aspect of the present invention can achieve both excellent low moisture permeability and scratch resistance. The optical thin film of the first aspect of the present invention includes the aforementioned resin layer formed by a cured product of a curable component in a laminated structure. This curable component includes the aforementioned polymeric compound A and polymeric compound B, and their ratio (polymeric compound A / polymeric compound B) is 95 / 5 to 10 / 90.

[0012] From the perspective of imparting excellent low moisture permeability to the aforementioned resin layer, the ratio of polymeric compound A to polymeric compound B (polymeric compound A / polymeric compound B) should preferably be 10 / 90 or higher, more preferably 15 / 85 or higher, or may also be 20 / 80 or higher, 25 / 75 or higher, 30 / 70 or higher, 35 / 65 or higher, 40 / 60 or higher, 45 / 55 or higher, 50 / 50 or higher, 55 / 45 or higher, 60 / 40 or higher, 65 / 35 or higher, 70 / 30 or higher, 75 / 25 or higher, 80 / 20 or higher, 85 / 15 or higher, or 90 / 10 or higher. On the other hand, from the perspective of the aforementioned resin layer achieving a higher level of both low moisture permeability and scratch resistance, and from the perspective of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is also possible to use 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 thin film of the first aspect of the present invention, the aforementioned polymeric compound B is preferably a 5-10 functional urethane (meth)acrylate. This configuration is preferred for increasing the crosslinking density of the aforementioned resin layer and thus improving scratch resistance.

[0014] In the optical thin film of the first aspect of the present invention, the thickness of the aforementioned resin layer is preferably 0.5 to 5 µm. As described above, even with a thinner resin layer, the optical thin film of the first aspect of the present invention can still impart excellent low moisture permeability and scratch resistance. When the optical thin film of the first aspect of the present invention is used as a protective film for a polarizing plate, from the viewpoint of enabling a thinner polarizing plate, the thickness of the aforementioned resin layer is preferably 4.5 µm or less, preferably 4 µm or less, or may be 3.2 µm or less, or 3 µm or less. From the viewpoint of achieving a higher level of both low moisture permeability and scratch resistance, the lower limit of the thickness of the aforementioned resin layer is preferably 1.0 µm or more, more preferably 1.8 µm or more, or may be 2 µm or more.

[0015] In the optical thin film of the first aspect of the present invention, the aforementioned light-transmitting substrate preferably comprises at least one selected from the group consisting of cellulose resins, polyester resins, acrylic resins, and cyclic olefin polymers. These resins are suitable for use as substrates for polarizer protective films.

[0016] Furthermore, the second aspect of the present invention provides a polarizing plate, wherein a polarizing element is disposed on the side opposite to the aforementioned resin layer of the optical thin film of the first aspect of the present invention. Furthermore, a third aspect of the present invention provides an image display device having the polarizing plate of the second aspect of the present invention. The image display device of the third aspect of the present invention preferably has an adhesive layer and an optical component sequentially laminated on the aforementioned resin layer.

[0017] In the polarizing plate of the second aspect of the present invention, the optical thin film of the first aspect of the present invention is used as a protective film for the polarizing plate. Therefore, even though the aforementioned resin layer is very thin, it still has excellent low moisture permeability and scratch resistance. Therefore, even though the image display device of the third aspect of the present invention, which has the polarizing plate of the second aspect of the present invention, is thin, it is not easy for the polarizing plate to fade in a humid environment, and its durability is excellent.

[0018] Invention Effects The polarizing plate obtained by using the optical film of the present invention as a protective film for the polarizing plate still has excellent low moisture permeability and scratch resistance even when thinned, and is not prone to fading of the polarizing element, with excellent durability. Simple Explanation of the Diagram

[0019] Figure 1 is a schematic diagram (cross-sectional view) showing one embodiment of the optical thin film of the present invention. Figure 2 is a schematic diagram (cross-sectional view) showing one embodiment of a polarizing plate having the optical thin film of Figure 1. Figure 3 is a schematic diagram (cross-sectional view) showing one embodiment of an image display device having the polarizing plate of Figure 2. Implementation

[0020] The first aspect of the present invention provides an optical thin film having a resin layer on one of the surface layers of a light-transmitting substrate. In this specification, the optical thin film of the first aspect of the present invention is sometimes referred to as the "optical thin film of the present invention". Also, in this specification, the aforementioned light-transmitting substrate and resin layer constituting the optical thin film of the present invention are sometimes referred to as the "light-transmitting substrate of the present invention" and the "resin layer of the present invention", respectively. Furthermore, the term "thin film" includes "sheet" and "strip". That is, the optical thin film of the present invention can also be in the form of a sheet or a strip.

[0021] A second aspect of the present invention provides a polarizing plate, wherein a polarizing element is disposed on the side of the optical thin film of the present invention opposite to the aforementioned resin layer. In this specification, the polarizing plate of the second aspect of the present invention is sometimes referred to as the "polarizing plate of the present invention". Furthermore, a third aspect of the present invention provides an image display device having the polarizing plate of the present invention. In this specification, the image display device of the third aspect of the present invention is sometimes referred to as the "image display device of the present invention".

[0022] Hereinafter, embodiments of the optical thin film of the present invention will be described with reference to the figures, but the present invention is not limited thereto and is merely an example.

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

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

[0025] Figure 3 is a schematic diagram (cross-sectional view) showing one embodiment of an image display device having the polarizing plate of Figure 2. The image display device 30 in Figure 3 has an image display panel 6 laminated on the adhesive layer 5 of the polarizing plate 20. In this embodiment, an adhesive layer 7 and an optical component 8 are sequentially laminated on the resin layer 1. The following is an explanation of each component.

[0026] <Optical Thin Films> The term "optical" in the optical film of this invention refers to its applicability for optical purposes, and more specifically, to its applicability in the manufacture of articles using optical components (optical articles). Examples of optical articles include input devices such as image display devices and touch panels, and it is suitable for use in the manufacture of liquid crystal image display devices, self-emissive image display devices (e.g., organic EL (electroluminescent) image display devices, LED image display devices), etc. More specifically, it is suitable for use as a protective film for polarizing plates constituting image display devices.

[0027] The optical film of the present invention is not particularly limited in form as long as it has a resin layer on one of the area layers of the light-transmitting substrate. For example, the optical film of the present invention may have a resin layer on only one side or on both sides. Furthermore, when the optical film of the present invention has resin layers on both sides, it may have a form in which both resin layers are provided by the resin layer of the present invention, or it may have a form in which 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 (another resin layer). When the optical film of the present invention is used as a protective film for a polarizing plate, it is preferable to have an optical film with a resin layer on only one side.

[0028] In addition to the light-transmitting substrate and the resin layer of the present invention, the optical film of the present invention may also have other layers on the surface or between any layers without compromising the effect of the present invention. These may include substrates other than the light-transmitting substrate of the present invention, resin layers other than the resin layer of the present invention, intermediate layers, base coatings, antistatic layers, separators, surface protective films, etc.

[0029] The optical thin film of the present invention preferably has a transmittance M1 [g / m²·24h] of 700 g / m²·24h or less in an environment of 40°C and 92% relative humidity. The aforementioned transmittance M1 of 700 g / m²·24h or less is ideal in that, when the optical thin film of the present invention is used as a protective film for a polarizing plate, it can suppress the "fading" of the polarizing element in a humidified environment. From the viewpoint of suppressing the fading of the polarizing element to a higher level, the aforementioned transmittance M1 is preferably 600 g / m²·24h or less, and may also be 550 g / m²·24h or less. The lower limit of the aforementioned moisture permeability M1 is not particularly limited. From the perspective of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is advisable to be 100g / m2·24h or higher, preferably 200g / m2·24h or higher, or 300g / m2·24h or higher, 310g / m2·24h or higher, or 320g / m2·24h or higher.

[0030] The optical thin film of the present invention preferably has a transmittance M2 [g / m2·24h] of 1,500 g / m2·24h or less in an environment of 60°C and 90% relative humidity. The aforementioned transmittance M2 of 1,500 g / m2·24h or less is ideal in that, when the optical thin film of the present invention is used as a protective film for a polarizing plate, it can suppress the "fading" of the polarizing element in a humidified environment. From the viewpoint of suppressing the fading of the polarizing element to a higher level, the aforementioned transmittance M2 is preferably 1,400 g / m2·24h or less, more preferably 1,300 g / m2·24h or less, and can also be 1,200 g / m2·24h or less. The lower limit of the aforementioned moisture permeability M2 is not particularly limited. From the perspective of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is advisable to be above 300 g / m2·24h, more preferably above 500 g / m2·24h, or even above 800 g / m2·24h.

[0031] The optical thin film of the present invention preferably has a transmittance M3 [g / m²·24h] of 2,000 g / m²·24h or less in an environment with a temperature of 65°C and a relative humidity of 90%. The aforementioned transmittance M3 of 2,000 g / m²·24h or less is ideal in that, when the optical thin film of the present invention is used as a protective film for a polarizing plate, it can suppress the "fading" of the polarizing element in a humidified environment. From the viewpoint of suppressing the fading of the polarizing element to a higher level, the aforementioned transmittance M3 is preferably 1,800 g / m²·24h or less, more preferably 1,600 g / m²·24h or less, and can also be 1,400 g / m²·24h or less. There is no particular limitation on the lower limit of the aforementioned moisture permeability M3. From the perspective of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is advisable to be above 500 g / m2·24h, more preferably above 750 g / m2·24h, or even above 1,000 g / m2·24h.

[0032] In the optical thin film of the present invention, the product (T×M1) of the thickness T [µm] of the resin layer and the moisture permeability M1 [g / m2·24h] of the optical thin film at a temperature of 40°C and a relative humidity of 92% is preferably 1,500 or less. The resin layer of the present invention imparts excellent low moisture permeability to the optical thin film. Generally, there is a tendency for higher moisture permeability with thicker film and lower moisture permeability with thinner film, exhibiting an inverse relationship. Therefore, the product (T×M1) of the thickness T [µm] of the resin layer and the aforementioned moisture permeability M1 can be used as an indicator of the moisture permeability inherent in the resin layer itself; the lower the product, the better the low moisture permeability. Therefore, the optical thin film of the present invention, with a resin layer having a product (T×M1) of 1,500 or less in a laminated structure, can still impart excellent low moisture permeability even when the resin layer is thinned, thus achieving both thinness and excellent low moisture permeability.

[0033] The aforementioned volume (T×M 1) of 1,500 or less is ideal from the following perspectives: when the optical film of the present invention is used as a protective film for a polarizing plate, it can still impart excellent low moisture permeability even when the resin layer of the present invention is thin, thereby suppressing the "fading" of the polarizing element in a humidified environment. From the viewpoint of balancing the suppression of fading of the polarizing element and the thinning of the resin layer of the present invention at a higher level, the aforementioned volume (T×M 1) is preferably 1,400 or less, more preferably 1,300 or less, and may also be 1,200 or less. There is no particular limitation on the lower limit of the aforementioned volume (T×M 1), but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing the polarizing element to "fade", it is preferably 500 or more, more preferably 600 or more, and may also be 700 or more.

[0034] In the optical thin film of the present invention, the product (T×M2) of the thickness T [µm] of the resin layer and the moisture permeability M2 [g / m2·24h] of the optical thin film at a temperature of 60°C and a relative humidity of 90% is preferably 3,000 or less. The product (T×M2), like the product (T×M1) mentioned above, can also serve as an indicator of the moisture permeability inherent in the resin layer itself; the lower it is, the better the low moisture permeability. Therefore, the optical thin film of the present invention, having a resin layer of the present invention with a product (T×M2) of 3,000 or less in a laminated structure, can still possess excellent low moisture permeability even when the resin layer is thinned, thus achieving both thinness and excellent low moisture permeability, which is ideal.

[0035] The aforementioned configuration with a volume (T×M 2) of 3,000 or less is ideal from the following perspective: when the optical film of the present invention is used as a protective film for a polarizing plate, even with a thin resin layer, "fading" of the polarizing element under humidified conditions can still be suppressed. From the viewpoint of achieving a higher level of both suppressing fading of the polarizing element and thinning of the resin layer of the present invention, the aforementioned volume (T×M 2) is preferably 2,900 or less, more preferably 2,800 or less, and may also be 2,700 or less. The lower limit of the aforementioned volume (T×M 2) is not particularly limited, but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is preferably 500 or more, more preferably 1,000 or more, and may also be 1,500 or more.

[0036] In the optical thin film of the present invention, the product of the aforementioned product (T×M1) and the aforementioned product (T×M2) ((T×M1)×(T×M2)) is preferably 4,500,000 or less. The aforementioned product ((T×M1)×(T×M2)) can also serve as an indicator of the moisture permeability of the resin layer itself, just like the aforementioned product (T×M1) and the aforementioned product (T×M2). The lower the product, the better the low moisture permeability. Therefore, the optical thin film of the present invention, with a resin layer having a product ((T×M1)×(T×M2)) of 4,500,000 or less in the laminated structure, can still possess excellent low moisture permeability even when the resin layer is thinned, thus achieving both thinness and excellent low moisture permeability, which is ideal.

[0037] The aforementioned configuration of a product ((T×M1)×(T×M2)) of 4,500,000 or less is ideal from the following perspective: when the optical film of the present invention is used as a protective film for a polarizing plate, even when the resin layer of the present invention is thin, the "fading" of the polarizing element under a humidified environment can still be suppressed. From the viewpoint of balancing the suppression of fading of the polarizing element and the thinning of the resin layer of the present invention at a higher level, the aforementioned product ((T×M1)×(T×M2)) is preferably 4,000,000 or less, and more preferably 3,500,000 or less. The lower limit of the aforementioned product ((T×M1)×(T×M2)) is not particularly limited, but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is preferably 50,000 or more, more preferably 100,000 or more, and may also be 150,000 or more.

[0038] In the optical thin film of the present invention, the product (T×M3) of the thickness T [µm] of the resin layer and the moisture permeability M3 [g / m2·24h] of the optical thin film at a temperature of 65°C and a relative humidity of 90% is preferably 4,000 or less. The product (T×M3), like the products (T×M1) and (T×M2) mentioned above, can also serve as an indicator of the moisture permeability inherent in the resin layer itself; the lower the product, the better the low moisture permeability. Therefore, the optical thin film of the present invention, having a resin layer with a product (T×M3) of 4,000 or less in a laminated structure, can still possess excellent low moisture permeability even when the resin layer is thinned, thus achieving both thinness and excellent low moisture permeability, which is ideal.

[0039] The aforementioned configuration with a volume (T×M 3) of 4,000 or less is ideal from the following perspective: when the optical film of the present invention is used as a protective film for a polarizing plate, even with a thin resin layer, "fading" of the polarizing element under humidified conditions can still be suppressed. From the viewpoint of achieving a higher level of both suppressing fading of the polarizing element and thinning of the resin layer of the present invention, the aforementioned volume (T×M 3) is preferably 3,800 or less, more preferably 3,600 or less, and may also be 3,400 or less. The lower limit of the aforementioned volume (T×M 3) is not particularly limited, but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is preferably 1,000 or more, more preferably 1,500 or more, and may also be 2,000 or more.

[0040] In the optical thin film of the present invention, the value obtained by subtracting the permeability M1 [g / m2·24h] of the aforementioned optical thin film at a temperature of 40°C and a relative humidity of 92% from 1,000 and dividing the resulting value by the thickness T [µm] of the aforementioned resin layer ((1,000-M1) / T) should preferably be 100 or more. The resin layer of the present invention imparts excellent low permeability to the optical thin film of the present invention. Generally speaking, the thicker the film, the higher the permeability, and the thinner the film, the lower the permeability. The aforementioned value "1,000" is the predicted value of the permeability of the light-transmitting substrate of the present invention (the light-transmitting substrate without the resin layer) at a temperature of 40°C and a relative humidity of 92%. The value obtained by subtracting the permeability M1 [g / m2·24h] from 1,000 is the predicted value of the reduction in permeability due to the resin layer being provided on the light-transmitting substrate of the present invention. Therefore, the aforementioned value ((1,000-M 1) / T) can be used as an indicator of the reduction in moisture permeability per 1µm thickness of the resin layer of the present invention at an environment of 40°C and 92% relative humidity. The higher the value, the better the low moisture permeability. Therefore, the optical film of the resin layer of the present invention with the aforementioned value ((1,000-M 1) / T) of 100 or above in the laminated structure can still possess excellent low moisture permeability even if the resin layer is thinned, thus becoming a product that combines thinness and excellent low moisture permeability.

[0041] The aforementioned value ((1,000-M 1) / T) of 100 or higher is ideal from the following perspectives: when the optical film of the present invention is used as a protective film for a polarizing plate, it can still impart excellent low moisture permeability even when the resin layer of the present invention is thin, thereby suppressing the "fading" of the polarizing element in a humidified environment. From the viewpoint of balancing the suppression of fading of the polarizing element and the thinning of the resin layer of the present invention at a higher level, the aforementioned value ((1,000-M 1) / T) is preferably 105 or higher, more preferably 110 or higher, and may also be 115 or higher. There is no particular limitation on the upper limit of the aforementioned value ((1,000-M 1) / T), but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing the polarizing element to "fade", it is preferably 500 or lower, more preferably 400 or lower, and may also be 300 or lower.

[0042] In the optical thin film of the present invention, the value obtained by subtracting the moisture permeability M2 [g / m2·24h] of the aforementioned optical thin film at a temperature of 60°C and a relative humidity of 90% from 2,000 and dividing the resulting value by the thickness T [µm] of the aforementioned resin layer ((2,000-M2) / T) should preferably be 200 or more. The aforementioned value "2,000" is a predicted value of the moisture permeability of the light-transmitting substrate itself (a light-transmitting substrate without a resin layer) at a temperature of 60°C and a relative humidity of 90%. The value obtained by subtracting the moisture permeability M2 [g / m2·24h] from 2,000 is the predicted value of the reduction in moisture permeability due to the application of the resin layer to the light-transmitting substrate of the present invention. Therefore, the aforementioned value ((2,000-M2) / T) can be used as an indicator of the reduction in moisture permeability per 1µm thickness of the resin layer at a temperature of 60°C and a relative humidity of 90%. The higher the value, the better the low moisture permeability. Therefore, the optical film of the present invention with the above value ((2,000-M 2) / T) of 200 or more in the laminated structure can still have excellent low moisture permeability even if the resin layer is thinned, thus becoming a product that combines thinness and excellent low moisture permeability.

[0043] The aforementioned value ((2,000-M²) / T) of 200 or higher is ideal from the following perspectives: when the optical film of the present invention is used as a protective film for a polarizing plate, it can still impart excellent low moisture permeability even when the resin layer of the present invention is thin, thereby suppressing the "fading" of the polarizing element in a humidified environment. From the viewpoint of balancing the suppression of fading of the polarizing element and the thinning of the resin layer of the present invention at a higher level, the aforementioned value ((2,000-M²) / T) is preferably 210 or higher, more preferably 220 or higher, and may also be 230 or higher. There is no particular limitation on the upper limit of the aforementioned value ((2,000-M²) / T), but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing the polarizing element to "fade", it is preferably 1,000 or lower, more preferably 800 or lower, and may also be 500 or lower.

[0044] In the optical thin film of the present invention, the product of the aforementioned value ((1,000-M 1) / T) and the aforementioned value ((2,000-M 2) / T) [((1,000-M 1) / T)×((2,000-M 2) / T)] is preferably 20,000 or more. The aforementioned product [(1,000-M 1) / T)×((2,000-M 2) / T)] can also serve as an indicator of the moisture permeability of the resin layer itself, just like the aforementioned values ​​(1,000-M 1) / T and ((2,000-M 2) / T). The higher the value, the better the low moisture permeability. Therefore, the optical film of the present invention, which has a resin layer of the present invention with a volume of 20,000 or more in the laminated structure [((1,000-M 1) / T)×((2,000-M 2) / T)], can still have excellent low moisture permeability even if the resin layer of the present invention is thinned, thus becoming an ideal product that combines thinness and excellent low moisture permeability.

[0045] The aforementioned configuration of [((1,000-M 1) / T)×((2,000-M 2) / T)] being 20,000 or more is ideal from the following perspective: when the optical film of the present invention is used as a protective film for a polarizing plate, even when the resin layer of the present invention is thin, the "fading" of the polarizing element under humidified conditions can still be suppressed. From the viewpoint of balancing the suppression of fading of the polarizing element and the thinning of the resin layer of the present invention at a higher level, the aforementioned product [((1,000-M 1) / T)×((2,000-M 2) / T)] is preferably 21,000 or more, and more preferably 22,000 or more. The upper limit of the aforementioned [((1,000-M 1) / T)×((2,000-M 2) / T)] is not particularly limited. From the perspective of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is advisable to be below 200,000, more preferably below 150,000, or even below 120,000.

[0046] In the optical thin film of the present invention, the value obtained by subtracting the moisture permeability M3 [g / m2·24h] of the aforementioned optical thin film at a temperature of 65°C and a relative humidity of 90% from 2,700 and dividing the resulting value by the thickness T [µm] of the aforementioned resin layer ((2,700-M3) / T) should preferably be 250 or higher. The aforementioned value "2,700" is a predicted value of the moisture permeability of the light-transmitting substrate itself (a light-transmitting substrate without a resin layer) at a temperature of 65°C and a relative humidity of 90%. The value obtained by subtracting the moisture permeability M3 [g / m2·24h] from 2,700 is the predicted value of the reduction in moisture permeability due to the application of the resin layer to the light-transmitting substrate of the present invention. Therefore, the aforementioned value ((2,700-M3) / T) can be used as an indicator of the reduction in moisture permeability per 1µm thickness of the resin layer at a temperature of 65°C and a relative humidity of 90%. The higher the value, the better the low moisture permeability. Therefore, the optical film of the present invention with the above value ((2,700-M 3) / T) of 250 or more in the laminated structure can still have excellent low moisture permeability even if the resin layer is thinned, thus becoming a product that combines thinness and excellent low moisture permeability.

[0047] The aforementioned value ((2,700-M 3) / T) of 250 or higher is ideal from the following perspectives: when the optical film of the present invention is used as a protective film for a polarizing plate, it can still impart excellent low moisture permeability even when the resin layer of the present invention is thin, thereby suppressing the "fading" of the polarizing element in a humidified environment. From the viewpoint of balancing the suppression of fading of the polarizing element and the thinning of the resin layer of the present invention at a higher level, the aforementioned value ((2,700-M 3) / T) is preferably 270 or higher, more preferably 280 or higher, and may also be 300 or higher. There is no particular limitation on the upper limit of the aforementioned value ((2,700-M 3) / T), but from the viewpoint of preventing moisture inside the polarizing plate from escaping to the outside and causing the polarizing element to "fade", it is preferably 1,000 or lower, more preferably 800 or lower, and may also be 600 or lower.

[0048] Regarding the optical film of the present invention, before and after the following scratch resistance test, the change in the moisture permeability [g / m2·24h] of the aforementioned optical film at a temperature of 40°C and a relative humidity of 92% should preferably be less than 20. • Scratch resistance test The surface of the aforementioned resin layer was rubbed back and forth 10 times under a load of 3.92 N and a moving speed of 100 mm / s using steel wool. Furthermore, generally speaking, the permeability after the abrasion resistance test tends to increase compared to the permeability before the test, but this also includes the possibility that the permeability after the abrasion resistance test decreases compared to the permeability before the test. Therefore, the aforementioned change is, for example, the absolute value of the permeability after the abrasion resistance test minus the permeability before the test.

[0049] The resin layer system of the present invention imparts excellent low moisture permeability to the optical film of the present invention. Generally speaking, the thicker the film, the higher the moisture permeability, and the thinner the film, the lower the moisture permeability. Furthermore, the resin layer system of the present invention imparts excellent scratch resistance to the optical film of the present invention. Generally speaking, the thicker the film, the higher the scratch resistance, and the thinner the film, the lower the scratch resistance. Therefore, the optical film of the present invention, which has the resin layer of the present invention in a laminated structure with the aforementioned change rate of 20 or less, can still impart excellent low moisture permeability and scratch resistance even if the resin layer of the present invention is thinned, thus becoming a product that combines thinness with excellent low moisture permeability and durability.

[0050] The aforementioned variation rate of 20 or less is ideal from the following perspectives: when the optical film of the present invention is used as a protective film for a polarizing plate, even when the resin layer of the present invention is thin, the surface hardness or scratch resistance is not easily reduced, thus preventing the reduction in low moisture permeability caused by damage, thereby suppressing the "fading" of the polarizing element. From the viewpoint of balancing the suppression of fading of the polarizing element and the scratch resistance of the resin layer of the present invention at a higher level, the aforementioned variation rate is preferably 18 or less, more preferably 15 or less, and may also be 12 or less or 10 or less. The lower limit of the aforementioned variation rate is not particularly limited, and it is most preferably 0, that is, no variation, while from the perspective of suppressing the "fading" of the polarizing element, it may also be about 0.1 or more to 0.5 or more.

[0051] The permeability M1, M2, and M3 of the optical thin film of the present invention, the product of the thickness T of the resin layer and the permeability M1, M2, or M3, the value ((1,000-M1) / T), the value ((2,000-M2) / T), the value ((2,700-M3) / T), and the change in permeability before and after the scratch resistance test, can be specifically determined by known methods, such as JIS Z0208. The permeability M1, M2, and M3 of the optical thin film of the present invention, the product of the thickness T of the resin layer and the permeability M1, M2, or M3, the value ((1,000-M1) / T), the value ((2,000-M2) / T), the value ((2,700-M3) / T), and the change in permeability before and after the scratch resistance test, can be adjusted by adjusting the type or thickness of the resin constituting the light-transmitting substrate of the present invention, and the above-described composition of the resin layer of the present invention.

[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 below 1.0%, and more preferably below 0.8%. The haze can be obtained according to JIS K 7136 (2000). The haze of the optical film of the present invention can be adjusted by the type or thickness of the resin constituting the light-transmitting substrate of the present invention, the type or thickness of the resin constituting the resin layer of the present invention, etc.

[0053] The total light transmittance of the optical thin film of the present invention in the visible light wavelength region is not particularly limited, but is preferably 85% or higher, and more preferably 88% or higher. The visible light wavelength region can be determined according to JIS K 7361-1. The total light transmittance of the optical thin film of the present invention can be adjusted by the type or thickness of the resin constituting the light-transmitting substrate of the present invention, the above-mentioned composition or thickness of the resin layer constituting the present invention, etc.

[0054] The thickness of the optical thin film of the present invention is not particularly limited. However, considering factors such as thinness, strength, and workability, it is preferable to have a thickness of 1 to 500 µm, more preferably 10 to 300 µm, and most preferably 20 to 200 µm.

[0055] <Light-transmitting substrate> Materials constituting the light-transmitting substrate of the present invention may include glass or plastic films. Examples of such plastic films include: cellulose resins such as cellulose triacetate (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), cyclic olefin polymers (COP) (e.g., trade names "ARTON" (manufactured by JSR Corporation), "ZEONOR" (manufactured by ZEON Corporation), etc.), polycarbonate resins, polyurethane resins, polyarylates, polyimide resins, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymers, etc. From the viewpoint of optical uniformity, smooth surface, and good secondary processing properties in the manufacture of polarizing plates, cellulose resins, acrylic resins, polyester resins, and cyclic olefin polymers (COP) are preferred, with cellulose resins being particularly preferred. Furthermore, these plastic materials can be used alone or in combination of two or more types.

[0056] The haze of the light-transmitting substrate of the present invention is not particularly limited, but from the viewpoint of obtaining good transparency, it is preferably 1.0% or less, and more preferably 0.8% or less. The haze can be obtained according to JIS K 7136 (2000). The haze of the light-transmitting substrate of the present invention can be adjusted by the type or thickness of the resin constituting the light-transmitting substrate of the present invention.

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

[0058] The thickness of the light-transmitting substrate of the present invention is not particularly limited. However, considering factors such as thinness, strength, workability, and other aspects, it is preferably in the range of 1 to 500 µm, more preferably in the range of 10 to 300 µm, and most preferably in the range of 20 to 200 µm.

[0059] The refractive index of the light-transmitting substrate of the present invention is not particularly limited, for example, it is in the range of 1.30 to 1.80, and preferably in the range of 1.40 to 1.70. Furthermore, the surface of the light-transmitting substrate of the present invention (the surface on which the resin layer is formed and / or the opposite side thereof) may be appropriately subjected to known and conventional surface treatments such as physical treatments such as corona discharge treatment and plasma treatment, and chemical treatments such as primer treatment.

[0060] <Resin Layer> The resin layer of this invention is laminated on one side of the light-transmitting substrate of this invention and imparts excellent low moisture permeability to the optical film of this invention. Furthermore, the resin layer of this invention also imparts excellent scratch resistance to the optical film of this invention. Therefore, the optical film of this invention having the resin layer of this invention in its laminated structure is suitable for use as a protective film for polarizing plates.

[0061] The resin layer of this invention should exhibit no damage after undergoing a scratch resistance test on its surface using steel wool under conditions of a load of 0.98 N, a moving speed of 100 mm / s, and 10 round trips. In other words, because the optical film of this invention is coated with the resin layer of this invention, which has excellent scratch resistance, it is not easily damaged during the manufacturing process, even when thinned. Therefore, when used as a protective film for polarizing plates, it can provide polarizing plates with excellent durability. The excellent scratch resistance of the resin layer of this invention can be achieved by adjusting the composition and thickness of the resin layer.

[0062] The resin layer of the present invention is formed by curing a curable composition, which includes: a polymeric compound A having cyclic aliphatic hydrocarbon groups and unsaturated double bonds, and a multifunctional polymeric compound B other than polymeric compound A. Sometimes, the curable composition containing polymeric compounds A and B of the present invention is referred to as the "curable composition of the present invention".

[0063] The aforementioned polymeric compound A possesses a highly hydrophobic chemical structure with cyclic aliphatic hydrocarbon groups, which imparts excellent low moisture permeability to the aforementioned resin layer. However, its large size makes its structure prone to loosening, thus easily reducing surface hardness or scratch resistance. On the other hand, polymeric compound B is multifunctional; by increasing the crosslinking density, the scratch resistance of the aforementioned resin layer can be improved. Therefore, the optical film of the present invention can achieve both excellent low moisture permeability and scratch resistance. The optical film of the present invention includes a resin layer formed by curing a curable component in a laminated structure. This curable component includes the aforementioned polymeric compound A and polymeric compound B, and their ratio (polymeric compound A / polymeric compound B) is 95 / 5 to 10 / 90. The curable component of the present invention may contain one polymeric compound A or two or more polymeric compounds A. Furthermore, the curable component of the present invention may contain one polymeric compound B or two or more polymeric compounds B.

[0064] From the perspective of imparting excellent low moisture permeability to the aforementioned resin layer, the ratio of polymeric compound A to polymeric compound B (polymeric compound A / polymeric compound B) should preferably be 10 / 90 or higher, more preferably 15 / 85 or higher, or may also be 20 / 80 or higher, 25 / 75 or higher, 30 / 70 or higher, 35 / 65 or higher, 40 / 60 or higher, 45 / 55 or higher, 50 / 50 or higher, 55 / 45 or higher, 60 / 40 or higher, 65 / 35 or higher, 70 / 30 or higher, 75 / 25 or higher, 80 / 20 or higher, 85 / 15 or higher, or 90 / 10 or higher. On the other hand, from the perspective of the aforementioned resin layer achieving a higher level of both low moisture permeability and scratch resistance, and from the perspective of preventing moisture inside the polarizing plate from escaping to the outside and causing "fading" of the polarizing element, it is also possible to use 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] The unsaturated double bond group of polymeric compound A is preferably (meth)acryl, vinyl, styrene, allyl, etc., with (meth)acryl being particularly preferred. Compounds containing two or more (meth)acryl groups per molecule are especially desirable examples.

[0066] The number of unsaturated double bonds in polymeric compound A is not particularly limited if it has one 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, more preferably three or more, and even more preferably four or more unsaturated double bonds. There is no particular upper limit to the number of unsaturated double bonds in polymeric compound A, and it may also be less than 10, less than 9, or less than 8.

[0067] The cyclic aliphatic hydrocarbon group present in polymeric compound A should preferably be derived from an alicyclic compound with 7 or more carbon atoms, more preferably from an alicyclic compound with 10 or more carbon atoms, and even more preferably from an alicyclic compound with 12 or more carbon atoms. The cyclic aliphatic hydrocarbon group is especially preferably derived from polycyclic compounds such as bicyclic and tricyclic compounds.

[0068] The cyclic aliphatic hydrocarbon group (including the linking group) is preferably a group represented by any one of the following general formulas (I) to (V), more preferably a group represented by the following general formulas (I), (II) or (IV), and even more preferably a group represented by the following general formula (I). [Chemical Formula 1]

[0069] In general formula (I), L and L' each independently represent a linked basis with 2 or more valences. n represents an integer from 1 to 3. [Chemical Formula 2]

[0070] In general formula (II), L and L' each independently represent a linked basis with 2 or more valences. n represents an integer from 1 to 2. [Chemical Formula 3]

[0071] In general formula (III), L and L' each independently represent a linked basis with 2 or more valences. n represents an integer from 1 to 2. [Chemical Formula 4]

[0072] In general formula (IV), L and L' each independently represent a linker with a valence of 2 or higher, and L" represents a hydrogen atom or a linker with a valence of 2 or higher. [Chemical Formula 5]

[0073] In the general formula (V), L and L' each independently represent a linkage base with two or more valences.

[0074] Cyclic aliphatic hydrocarbon groups can be specifically listed as 1- to 3-valent groups derived from norane, tricyclic decane, tetracyclic dodecane, pentacyclic pentadecane, adamantane, and diadamantane.

[0075] Polymerizable compound A, comprising a group represented by any one of the general formulas (I) to (V) as a cyclic aliphatic hydrocarbon group, has polymerizable functional groups via linking groups represented by L, L', and L" . Linking groups may include: single bonds, alkyl groups that can be substituted with 1 to 6 carbon atoms, amide groups that can be disubstituted at the N-position, aminomethyl groups that can be disubstituted at the N-position, ester groups, oxycarbonyl groups, ether groups, and groups obtained by combining the above.

[0076] Polymerizable compound A can be readily synthesized, for example, by a one- or two-stage reaction of polyols such as diols and triols having the aforementioned cyclic aliphatic hydrocarbon groups with carboxylic acids, carboxylic acid derivatives, epoxy derivatives, and isocyanate derivatives having compounds such as (meth)acrylic acid, vinyl, styrene, and allyl. It can also be synthesized by reacting polyols having the aforementioned cyclic aliphatic hydrocarbon groups with polyols such as (meth)acrylic acid, (meth)acrylic chloride, (meth)acrylic anhydride, (meth)acrylic acid glycidyl acrylate, and 1,1-bis(acryloyloxymethyl)ethyl isocyanate.

[0077] The following shows ideal specific examples of polymeric compound A, but the present invention is not limited thereto. [Chemical Formula 6] [Chemical Formula 7] [Chemical Formula 8] [Chemical Formula 9] [Chemical Formula 10] [Chemical Formula 11]

[0078] The content of polymeric 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, the content of non-volatile solids in the curable composition of the present invention is preferably 10% by weight or more, more preferably 15% by weight or more, or may also 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. On the other hand, from the viewpoint that the resin layer of the present invention can achieve a higher level of both low moisture permeability and scratch resistance, it can also 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] The polymerizable functional group of polymerizable compound B should preferably be an unsaturated double bond such as (meth)acryl, vinyl, styrene, or allyl, with (meth)acryl being particularly preferred. Compounds containing two or more (meth)acryl groups per molecule are especially desirable examples.

[0080] Further, regarding the aforementioned polymeric compound B, it is a multifunctional polymeric compound other than polymeric compound A, that is, a compound that does not have cyclic aliphatic hydrocarbon groups in its molecule but has two or more polymeric functional groups. Polymeric compound A, due to the stereostructure of the cyclic aliphatic hydrocarbon groups in its molecule, has easily reduced scratch resistance. We believe that the hardening composition of this invention, in addition to polymeric compound A, also contains polymeric compound B, thereby increasing the crosslinking density and improving scratch resistance.

[0081] The number of polymerizable functional groups in polymeric compound B is not particularly limited if it is two or more. However, in terms of imparting excellent scratch resistance to the optical thin film of the present invention, it is preferable to have three or more, more preferably four or more, or five or more, six or more, seven or more, eight or more, nine or more, or ten or more. The upper limit of the number of polymerizable functional groups in polymeric compound B is not particularly limited, and may be less than 30, less than 25, or less than 20. In particular, the number of polymerizable functional groups is preferably 5 to 10, and more preferably 8 to 10.

[0082] Polymerizable compound B can be a monomer (hereinafter sometimes referred to as "polymerizable monomer B") that does not have a cyclic aliphatic hydrocarbon group in its molecule but has two or more polymerizable functional groups, or an oligomer (hereinafter sometimes referred to as "polymerizable oligomer B") that does not have a cyclic aliphatic hydrocarbon group in its molecule but has two or more polymerizable functional groups. The curing composition of the present invention may contain only the polymerizable monomer as polymerizable compound B, may contain only the polymerizable oligomer B, or may contain both polymerizable monomer B and polymerizable oligomer B. From the viewpoint of achieving a high crosslinking density, it is preferable to include at least polymerizable oligomer B.

[0083] Examples of polymerizable monomer B include: hexanediol di(meth)acrylate, butanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl tetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, neopentyl tetraethylene tetra(meth)acrylate, neopentyl tetraethylene tri(meth)acrylate, dinepentyl tetraethylene hexa(meth)acrylate, tris(2-hydroxyethyl) triisocyanate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, etc. The curable composition of this invention may contain one polymerizable monomer B, or it may contain two or more polymerizable monomers B.

[0084] Polymerizable oligomer B is a compound containing two or more repeating units and having polymerizable functional groups. That is, polymerizable oligomer B is a polymer with polymerizable functional groups within its molecule. Examples of polymerizable oligomer B include: urethane (meth)acrylates with two or more (meth)acrylic groups added as functional groups to a urethane backbone; polyester (meth)acrylates with two or more (meth)acrylic groups added as functional groups to a polyester backbone; and epoxy (meth)acrylates with two or more (meth)acrylic groups added as functional groups to an epoxy backbone. From the viewpoint of achieving a high crosslinking density, it is preferable to include at least an urethane (meth)acrylate, and more preferably a 5- to 10-functional urethane (meth)acrylate. The curable composition of the present invention may contain one polymerizable oligomer B, or it may contain two or more polymerizable oligomers B.

[0085] Carbamate (meth)acrylates can be obtained, for example, by reacting polyols, isocyanates and (meth)acrylate hydroxy esters. The polyols constituting carbamate (meth)acrylates can be of any known type, but from the viewpoint of increasing crosslinking density, polyols with three or more hydroxyl groups (preferably four or more, more preferably five or more, and even more preferably six or more) are preferable. Examples include trimethylolpropane, ethoxylated isocyanuric acid, neopentyl tertrol, dinepentyl tertrol, trinepentyl tertrol, and tetranepentyl tertrol. These polyols can be used alone or in mixtures of two or more.

[0086] The isocyanates constituting carbamate (meth)acrylates can be polyisocyanates composed of chain saturated hydrocarbons, cyclic saturated hydrocarbons, or aromatic hydrocarbons. Examples of such polyisocyanates include: chain saturated hydrocarbon isocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate; cyclic hydrocarbon isocyanates such as isoflavone diisocyanate, dicyclohexylmethane diisocyanate, methylene bis(4-cyclohexyl) isocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated toluene diisocyanate; toluene 2,4-diisocyanate; 1,3-enyl diisocyanate; p-enylphenyl diisocyanate; 3,3'-dimethyl-4,4'-diisocyanate; 6-isopropyl-1,3-phenyl diisocyanate; and 1,5-naphthalene diisocyanate, among other aromatic polyisocyanates. Ideal examples include isophorone diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. These polyisocyanates can be used alone or in combination of two or more.

[0087] Examples of hydroxy methacrylates constituting carbamate esters include 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, and 6-hydroxyhexyl methacrylate. These hydroxy methacrylates can be used alone or in combination of two or more.

[0088] Examples of carbamate (meth)acrylates include the ART RESIN UN series manufactured by Nekami Industrial Co., Ltd., the NK oligomer U series manufactured by Shin-Nakamura Chemical Industry Co., Ltd., and the UV series manufactured by Mitsubishi Chemical Co.

[0089] Polyester (meth)acrylates can be obtained, for example, by reacting the terminal hydroxyl groups of polyesters obtained by polymerizing (meth)acrylic acid with polyols and polycarboxylic acids. Specific examples of polyester (meth)acrylates include ARONIX M-6000, ARONIX M-7000, ARONIX M-8000 and ARONIX M-9000 manufactured by Toa Synthetic Co., Ltd.

[0090] Epoxy (meth)acrylates can be obtained, for example, by reacting (meth)acrylic acid with epoxy resin. Specific examples of epoxy (meth)acrylates include Ripoxy SP and Ripoxy VR manufactured by Showa Polymer Co., Ltd., and the epoxy ester series manufactured by Kyoei Chemical Co., Ltd.

[0091] The weight-average molecular weight of polymeric 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 preferable to be 400 or more, more preferably 500 or more, more preferably 600 or more, and especially preferably 700 or more. Furthermore, from the viewpoint of the coatability of the curable composition of the present invention, the weight-average molecular weight of polymeric oligomer B is preferably 10,000 or less, more preferably 7,000 or less, and even more preferably 5,000 or less. The weight-average molecular weight of polymeric oligomer B can be determined, for example, using a high-performance liquid chromatography (HPLC) instrument. For example, an HPLC8020 manufactured by Tosoh Corporation can be used, with two TSKgelGMH-H (20) columns connected in series as the columns, and tetrahydrofuran as the solvent, at a flow rate of 0.5 mL / min to determine the weight-average molecular weight.

[0092] The content of polymeric compound B in the curing composition of the present invention is not particularly limited. However, from the viewpoint of imparting excellent scratch resistance to the resin layer of the present invention, the content of non-volatile solids in the curing composition of the present invention is preferably 5% by weight or more, more preferably 10% by weight or more, more preferably 15% by weight or more, or 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 that the resin layer of the present invention can achieve a higher level of both low moisture permeability and scratch resistance, it can also 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 this invention preferably includes a polymerization initiator, and the polymerization initiator is preferably a photopolymerization initiator. Examples of photopolymerization initiators include: diphenyl ethylene glycol (benzil), diphenyl ketone, benzoic acid, 3,3'-dimethyl-4-methoxydiphenyl ketone, and other diphenyl ketone compounds; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl) ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxyphenylacetone, and α-hydroxycyclohexylphenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-di... Acetophenone compounds such as ethoxyacetophenone and 2-methyl-1-[4-(methylthio)-phenyl]-2-morphofolinylprop-1-one; benzoin alkyl ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and benzoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-benzophenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; 9-oxosulfuron 2-Chloro-9-oxysulfur 2-Methyl-9-oxosulfur 2,4-Dimethyl-9-oxosulfur Isopropyl-9-oxosulfur 2,4-Dichloro-9-oxosulfur 2,4-Diethyl-9-oxosulfur 2,4-Diisopropyl-9-oxosulfuron Dodecyl 9-oxosulfur 9-Oxysulfur These compounds include camphorquinone, halogenated ketones, propylphosphine oxides, and propylphosphonates. These polymerization initiators can be used alone or in combination of two or more.

[0094] The content of the photopolymerization initiator in the curable composition of the present invention is not particularly limited. However, from the viewpoint that the resin layer of the present invention fully obtains low moisture permeability and scratch resistance, it is preferable to be 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and even more preferably 0.2 parts by weight or more, relative to 100 parts by weight of the polymeric compound (the total of polymeric compound A and polymeric compound B). Furthermore, from the viewpoint that the photopolymerization initiator should not excessively absorb radiation, thus preventing the curing of the curable composition of the present invention from occurring sufficiently, the content of the photopolymerization initiator in the curable composition of the present invention is preferably 10 parts by weight or less, more preferably 8 parts by weight or less, relative to 100 parts by weight of the polymeric compound (the total of polymeric compound A and polymeric compound B).

[0095] Various leveling agents can be added to the curing composition of this invention. The aforementioned leveling agents, such as fluorinated or polysiloxane-based leveling agents, can be used to prevent uneven coating (uniform coating surface). When antifouling properties are required on the surface of the resin layer of this invention, leveling agents can also be appropriately blended in. The amount of the aforementioned leveling agent mixed with 100 parts by weight of polymeric compound (the total of polymeric compound A and polymeric compound B) is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight.

[0096] The curable composition of this invention may contain a solvent. Various solvents can be used as solvents, taking into account the solubility of the polymeric compounds (polymeric compound A and polymeric compound B) and their drying properties during application. Examples of such organic solvents include: dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dimethyl ether, 1,3-dimethyl monoxide, 1,3,5-trimethyl monoxide, tetrahydrofuran, anisole, phenethyl ether, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl cyclohexanone, ethyl formate, propyl formate, amyl 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-diethoxyacetone, acetoacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, methanol, ethanol, isopropanol, n-butanol, cyclohexanol, 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., can be used alone or in combination of two or more.

[0097] The curing components of this invention may also include, as needed and without impairing the effects of this invention, any suitable additives such as plasticizers, surfactants, antioxidants, ultraviolet absorbers, thixotropic agents, and antistatic agents.

[0098] The film thickness of the resin layer of the present invention is preferably 0.5~5µm. As mentioned above, even when the resin layer of the present invention is thinned, it still imparts excellent low moisture permeability and scratch resistance to the optical film of the present invention. When the optical film of the present invention is used as a protective film for a polarizing plate, from the viewpoint of enabling a thinner polarizing plate, the film thickness of the aforementioned resin layer is preferably 4.5µm or less, preferably 4µm or less, or 3.2µm or less, or 3µm or less. From the viewpoint of achieving a higher level of both low moisture permeability and scratch resistance, the lower limit of the film thickness of the resin layer of the present invention is preferably 1.0µm or more, more preferably 1.8µm or more, or 2µm or more. The resin layer of the present invention can be a single layer or multiple layers. When the resin layer of the present invention is composed of multiple layers, the film thickness of the resin layer of the present invention is the sum of the thickness of each of the multiple layers.

[0099] The resin layer of the present invention can be formed by mixing polymeric compound A and polymeric compound B with polymeric compounds other than polymeric compound A and polymeric compound B, photopolymerization initiator, leveling agent, solvent, other additives, etc., as needed to prepare a coating liquid (the curing component of the present invention), applying the coating liquid to one side of a light-transmitting substrate and drying it to harden the coating film.

[0100] The concentration of solid components in the application solution should preferably be 1% to 70% by weight, more preferably 2% to 50% by weight, and even more preferably 5% to 40% by weight.

[0101] Examples of coating methods for coating liquids include: dip coating, air knife coating, curtain coating, roller coating, wire rod coating, gravure coating, mold coating, extrusion coating, and bar coating.

[0102] The curing of the coating can be appropriately selected according to the type of curing component. When the curing component is photocurable, it can be cured by irradiating it with a light source that emits light of the required wavelength. For example, light with an exposure dose of 150 mJ / cm² or higher can be used, preferably 200 mJ / cm² to 1000 mJ / cm². Alternatively, heating can be applied during the photocuring process. Light can be categorized into, for example, ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, or ultraviolet light, with ultraviolet light being particularly preferred. Furthermore, there are no particular limitations on the irradiation time or method, as long as it can activate the photopolymerization initiator and trigger the reaction of the polymerizable compound.

[0103] <Polarizing plate> The polarizing plate of the present invention has a laminated structure in which a polarizing element 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 polarizing element 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 protective film for the polarizing plate, the polarizing plate 20 still has excellent low moisture permeability and scratch resistance even if the resin layer 1 is very thin, and is not prone to quality deterioration such as fading of the polarizing element 3. In this embodiment, a second light-transmitting substrate 4 and an adhesive layer 5 are further sequentially laminated on the side opposite to the optical film 10 of the polarizing element 3.

[0104] The polarizing element 3 is a component that allows light with a fixed polarization plane to pass through only. Known materials can be used without limitation, such as polyvinyl alcohol (PVA) polarizing films. The PVA polarizing film can be one that has been dyed with iodine or one that has been dyed with a dichroic dye.

[0105] Polyvinyl alcohol (PVA) polarizing films can be films that have undergone uniaxial stretching of a PVA film and then dyed with iodine or dichroic dyes (preferably films that have undergone further durability treatment with boron compounds); or films that have undergone uniaxial stretching after dyeing with iodine or dichroic dyes (preferably films that have undergone further durability treatment with boron compounds). The absorption axis of the polarizing element is parallel to the stretching direction of the film.

[0106] The thickness of polarizing element 3 should be 5~25µm, while from the viewpoint of making polarizing plate 20 thinner, it is more appropriate to be 10~15µm.

[0107] The second light-transmitting substrate 4 protects the polarizing element 3 on the opposite side of the optical film 10 (polarizing plate protective film). It can be made of the same glass or plastic film as the light-transmitting substrate of this invention, preferably a cellulose-based resin, a cyclic olefin polymer (COP), or a polycarbonate-based resin, and more preferably a cyclic olefin polymer (COP) or a polycarbonate-based resin. The light-transmitting substrate 4 can be made of the same material as the light-transmitting substrate 2, or it can be made of different materials. The light-transmitting substrate 4 can have a resin layer 1 laminated, or it can be without a resin layer 1. Furthermore, the light-transmitting substrate 4 can be a single layer, or it can be a laminated structure of two or more layers, either the same or different.

[0108] Furthermore, the light-transmitting substrate 4 is also preferably an optical compensation film (phase retardation film) having an optical compensation layer comprising an optical anisotropic layer. The optical compensation film can, for example, improve the viewing angle characteristics of a liquid crystal display. Known materials can be used without limitation for the optical compensation film; for example, the phase retardation film described in Japanese Patent Application Publication No. 2014-194484 can also be used.

[0109] The thickness of the light-transmitting substrate 4 should preferably be 5~25µm, while from the viewpoint of making the polarizing plate 20 thinner, it is more appropriate to be 10~15µm.

[0110] Adhesive layer 5 is formed by any suitable adhesive. Materials constituting adhesive layer 5 may include, for example, materials using the following polymers as the base polymer: acrylic polymers, polysiloxane polymers, polyesters, polyurethanes, polyamides, polyethers, fluoropolymers, rubber polymers, isocyanate polymers, polyvinyl alcohol polymers, gelatin polymers, vinyl polymers, latex polymers, and water-based polyesters. From the viewpoint of low moisture permeability, materials using acrylic polymers and / or rubber polymers as the base polymer are preferable. Adhesive layer 5 may contain a single base polymer or may contain two or more base polymers.

[0111] The thickness of the adhesive layer 5 should be 5~25µm, but from the viewpoint of making the polarizing plate 20 thinner, it is more appropriate to be 10~20µm.

[0112] The polarizing plate 20 can be obtained by bonding the polarizing element 1 and the optical film 10 together with an adhesive. Furthermore, the polarizing element 1 and the light-transmitting substrate 4 can also be bonded together with an adhesive. The adhesive used for bonding can be a fully saponified polyvinyl alcohol aqueous solution (glue), or an active energy line curing adhesive can be used.

[0113] The adhesive layer 5 can be formed by coating an adhesive composition comprising a base polymer constituting the adhesive onto the light-transmitting substrate 4 and curing it as needed after drying. Alternatively, it can be formed by forming the adhesive layer 5 on the release element in the same manner and then attaching or transferring it onto the light-transmitting substrate 4.

[0114] Layers other than the polarizing plate 20, optical film 10, polarizing plate 3, light-transmitting substrate 4, and adhesive layer 5 (such as surface protective film, separator, etc.) may also be present on the surface or between any layers. For example, the surface of adhesive layer 5 may be protected by a separator, and the surface of resin layer 1 of optical film 10 may also be protected by a surface protective film.

[0115] The thickness of the polarizing plate 20 (including the total thickness of the light-transmitting substrate 4 and the adhesive layer 5) should preferably be 50~100µm, but from the viewpoint of making the polarizing plate 20 thinner, it is more appropriate to be 60~75µm.

[0116] <Image Display Device> The image display device of the present invention incorporates the polarizing plate of the present invention. Because the image display device of the present invention incorporates the polarizing plate of the present invention in its laminated structure, even if the resin layer 1 is very thin, it still exhibits excellent low moisture permeability and scratch resistance, and is less prone to quality degradation such as fading of the polarizing element 3. Therefore, even if the image display device of the present invention is thin, it is not prone to fading of the polarizing plate in humidified environments, exhibiting excellent durability. In Figure 3, the image display device 30 has an image display panel 6 laminated on the adhesive layer 5 of the polarizing plate 20. In this embodiment, an adhesive layer 7 and an optical component 8 are sequentially laminated on the resin layer 1.

[0117] The image display panel 6 is not particularly limited, and can be exemplified by liquid crystal image display panels, self-emissive image display panels (such as organic EL (electroluminescent) image display panels, LED image display panels, etc.).

[0118] The image display panel is formed by alternating RGB elements, and in order to improve contrast, the spaces between the RGB elements should be filled with a black matrix (BM).

[0119] Adhesive layer 7 may be made of a material containing the same base polymer as that illustrated in adhesive layer 5. From the viewpoint of low moisture permeability, it is preferable to use an acrylic polymer and / or a rubber polymer as the base polymer. Adhesive layer 7 may contain a single base polymer or may contain two or more base polymers. Adhesive layer 7 may be made of the same material as adhesive layer 5 or may be made of different materials.

[0120] The optical component 8 can be made of the same glass or plastic film as the light-transmitting substrate of the present invention, preferably an acrylic resin, a polyester resin, or a cyclic olefin polymer (COP), and especially preferably a polyester resin. When the optical component 8 is located on the outermost surface of the viewing side of the image display device 30, it functions as a covering component.

[0121] The image display device 30 may also include optical components other than the optical thin film 10, polarizing plate 3, light-transmitting substrate 4, adhesive layer 5, image display panel 6, adhesive layer 7, and optical components 8 on its surface or between any layers. The aforementioned optical components are not particularly limited and may include polarizing plates other than the polarizing plate 3, retardation plates, anti-reflective films, viewing angle adjustment films, optical compensation films, etc. Furthermore, the aforementioned optical components may also include components that maintain the visibility of the image display device or input device while also serving a decorative or protective function (such as design films, decorative films, or surface protection plates).

[0122] The image display device 30 can be manufactured by laminating an optical film formed by bonding an image display panel 6, a polarizing plate 20, an optical component 8, and an adhesive layer 7. Specifically, this lamination can be carried out under heat and / or pressure. Alternatively, after lamination under heat and / or pressure, the material can be cured by irradiating active energy lines. The irradiation of the active energy lines can be performed in the same manner as the formation of the resin layer of this invention.

[0123] Example The present invention will now be described in more detail with reference to embodiments, but the present invention is not limited to these embodiments.

[0124] Example 1 (Preparation of coating solution for resin layer formation) The resins contained in the resin layer are prepared as follows: 90 parts by weight of UV-curable acrylate resin (manufactured by Shin-Nakamura Chemical Co., trade name "A-DCP", 100% solids) and 10 parts by weight of UV-curable acrylate resin (manufactured by Mitsubishi Chemical Co., trade name "UV-1700TL", 80% solids). For every 100 parts by weight of the aforementioned resin solids, 5 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") and 0.2 parts by weight of leveling agent (manufactured by Kyoeisha Chemical Co., trade name "LE-303", 40% solids) are mixed. This mixture is diluted with a MIBK / cyclopentanone mixed solvent (60 / 40 by weight) to a solids concentration of 30% to prepare a coating solution for forming the resin layer.

[0125] Modulation of Optical Thin Films A transparent plastic film substrate (TAC, FUJIFILM (stock), trade name "TJ25UL") was prepared as a light-transmitting substrate. A coating film was formed on one side of the transparent plastic film substrate using a rod coater #7 with the resin layer forming coating liquid prepared above. Then, the transparent plastic film substrate with the coating film was conveyed to a drying step. In the drying step, the coating film was dried by heating at 60°C for 1 minute. Afterwards, the coating film was hardened by irradiation with ultraviolet light with a cumulative light intensity of 220 mJ / cm² using a high-pressure mercury lamp to form a resin layer with a thickness of 2.5 µm, thus obtaining the optical film 1 of Example 1. The details of the resin used in Example 1 are as follows. • A-DCP: Tricyclodecanediethanol dimethacrylate ·UV-1700TL: 10-functional amino formate acrylate

[0126] Example 2 The resin contained in the resin layer is composed of 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. Otherwise, the optical film 2 of Example 2 is obtained in the same manner as in Example 1.

[0127] Example 3 The resin contained in the resin layer is composed of 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. Otherwise, the optical film 3 of Example 3 is obtained in the same manner as in Example 1.

[0128] Comparative Example 1 The resin contained in the resin layer is 100 parts by weight (in terms of solid content) of A-DCP. Otherwise, the optical film 4 of Comparative Example 1 was obtained in the same manner as in Example 1.

[0129] Comparative Example 2 The resin contained in the resin layer is 100 parts by weight (in terms of solid content) of UV-1700TL. Otherwise, the optical film 5 of Comparative Example 2 was obtained in the same manner as in Example 1.

[0130] (Evaluate) The optical thin films obtained in the above embodiments and comparative examples were used for the following evaluation. The evaluation methods are shown below. The results are listed in Table 1.

[0131] (1) Film thickness measurement Using a digital linear gauge (trade name "MODEL D-10HS", manufactured by Ozaki Manufacturing Co., Ltd.), the film thickness of the optical films in the examples and comparative examples was measured at five points relative to the width, and the average of the film thicknesses at the five points was taken as the total thickness. The film thickness of the light-transmitting substrates used in the examples and comparative examples was measured using the same method, and the average of the film thicknesses at the five points 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) Measurement of moisture permeability Following JIS Z0208, the water transmittance of the optical thin films of the examples and comparative examples was measured at 40°C and 92% relative humidity.

[0133] (3) Assessment of fading of polarizing components After storing the optical films of the examples and comparative examples at 60°C and 90% for 120 hours, the backlight illuminance was set to 8000 candela in a darkroom and the film was observed. If unevenness or streaks were observed during the fading, it was determined that the polarizing element had faded.

[0134] (4) Abrasion resistance test The optical films of the examples and comparative examples were cut into pieces of 5cm × 15cm. #0000 steel wool was then brought into contact with the surface of the resin layer with a diameter of 2.5cm and a contact area of ​​6.25 × πcm². A load of 100gf (0.98N) was applied to the steel wool, and the resin layer surface was rubbed back and forth 10 times relative to the long side of the film at a moving speed of 100mm / s. Under fluorescent and LED light sources, visually inspect the central 5cm x 5cm portion of the film after the test for any damage.

[0135] [Table 1]

[0136] (5) Measurement of moisture permeability The temperature and humidity conditions for the experiment were set to 60°C and 90% relative humidity or 65°C and 90% relative humidity. The humidity transmittance of the optical films of Examples 2 and 3 was measured in the same manner as the temperature and humidity conditions of 40°C and 92%. Table 2 shows: the product of the resin layer thickness [µm] and the moisture permeability [g / m²·24h] of the optical film at 40℃ and 92% relative humidity (1); the product of the resin layer thickness [µm] and the moisture permeability [g / m²·24h] of the optical film at 60℃ and 90% relative humidity (2); the product of the resin layer thickness [µm] and the moisture permeability [g / m²·24h] of the optical film at 65℃ and 90% relative humidity (3); the product of (1) and (2) ((1)×(2)); the value obtained by subtracting the moisture permeability [g / m²·24h] of the optical film at 40℃ and 92% relative humidity from 1,000 and dividing it by the resin layer thickness [µm] (4); and the value obtained by subtracting the moisture permeability [g / m²·24h] of the optical film at 60℃ and 90% relative humidity from 2,000. 2.24h] and the value obtained is divided by the resin layer thickness [µm] (5), the value obtained is subtracted from 2,700 the optical film's permeability [g / m 2.24h] at a temperature of 65℃ and a relative humidity of 90% and the value obtained is divided by the resin layer thickness [µm] (6), the product of value (4) and value (5) ((4)×(5)). [Table 2]

[0137] (6) Measurement of moisture permeability after abrasion resistance test The optical films of Examples 2 and 3 were cut into pieces of 5cm × 15cm. #0000 steel wool was then brought into contact with the surface of the resin layer using steel wool with a diameter of 2.5cm and a contact area of ​​6.25 × πcm². A load of 400gf (3.92N) was applied to the steel wool, and the resin layer surface was rubbed back and forth 10 times relative to the long side of the film at a moving speed of 100mm / s. The moisture permeability was then measured at 40°C and 92% relative humidity using the same method as described above. In terms of the change in moisture permeability after the abrasion resistance test, Example 2 showed a change of 9 g / m²·24h, while Example 3 showed a change of 1 g / m²·24h.

[0138] The following are variations of the present invention. [Note 1] An optical thin film having a resin layer on one of the surface layers of a light-transmitting substrate; The aforementioned resin layer is formed by curing a curable composition, which includes: a polymeric compound A having cyclic aliphatic hydrocarbon groups and unsaturated double bonds, and a multifunctional polymeric compound B other than polymeric compound A; and The ratio of polymeric compound A to polymeric compound B (polymeric compound A / polymeric compound B) is 95 / 5 to 10 / 90. [Note 2] As in the optical film of Note 1, the aforementioned polymeric compound B is a 5-10 functional carbamate (meth) acrylate. [Note 3] As in Note 1 or 2, the thickness of the aforementioned resin layer is 0.5~5µm. [Note 4] The optical film as described in any of Notes 1 to 3, wherein the aforementioned light-transmitting substrate comprises at least one selected from the group consisting of cellulose resins, polyester resins, acrylic resins and cyclic olefin polymers. [Note 5] A polarizing plate having a polarizing element disposed on the side opposite to the aforementioned resin layer of an optical film as described in any one of Notes 1 to 4. [Note 6] An image display device having a polarizing plate as described in Note 5. [Note 7] As in Note 6, the image display device has an adhesive layer and an optical component sequentially laminated on the aforementioned resin layer.

[0139] 10: Optical thin films 1: Resin layer 2: Light-transmitting substrate 20:Polarizing plate 3:Polarizer 4: Light-transmitting substrate (optical compensation film) 5: Adhesive layer 30: Image display device 6: Image display panel 7: Adhesive layer 8: Optical components

Claims

1. An optical thin film having a resin layer on one of the surface layers of a light-transmitting substrate; wherein the resin layer is formed by curing a curable composition comprising: a polymeric compound A having cyclic aliphatic hydrocarbon groups and unsaturated double bonds, and a polyfunctional polymeric compound B other than the aforementioned polymeric compound A; wherein the aforementioned polymeric compound B is a carbamate (meth)acrylate, which is obtained by reacting a polyol, a polyisocyanate, and a (meth)acrylate hydroxyl ester; wherein the aforementioned polyol is selected from one or more of the group consisting of trimethylolpropane, ethoxylated isocyanuric acid, neopentyl tertrol, dinepentyl tertrol, trinepentyl tertrol, and tetranepentyl tertrol; wherein the weight ratio of the aforementioned polymeric compound A to the aforementioned polymeric compound B (polymeric compound A / polymeric compound B) is 95 / 5 to 10 / 90.

2. The optical film of claim 1, wherein the aforementioned polymeric compound B is a 5-10 functional carbamate (meth)acrylate.

3. The optical thin film of claim 1 or 2, wherein the thickness of the aforementioned resin layer is 0.5~5µm.

4. The optical film of claim 1 or 2, wherein the aforementioned light-transmitting substrate comprises at least one selected from the group consisting of cellulose resins, polyester resins, acrylic resins and cyclic olefin polymers.

5. The optical film of claim 3, wherein the aforementioned light-transmitting substrate comprises at least one selected from the group consisting of cellulose resins, polyester resins, acrylic resins and cyclic olefin polymers.

6. A polarizing plate having a polarizing element disposed on the side opposite to the aforementioned resin layer of an optical film as claimed in any one of claims 1 to 5.

7. An image display device having a polarizing plate as claimed in claim 6.

8. The image display device of claim 7, wherein an adhesive layer and an optical component are sequentially laminated on the aforementioned resin layer.

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