TW202330250A - Laminate film, optical laminate, and image display device - Google Patents

Abstract

This invention provides a laminate film, an optical laminate including the laminate film and a circular polarizing plate, and an image display device including the optical laminate. The laminated film includes a substrate film and an optical function layer (A) laminated thereon, wherein the laminated film has a luminous reflectance Y of 9.0% or less, and an a* of reflection hue of 0.3 or more and 7.0 or less, and a b* of reflection hue of -10.0 or more and 0 or less.

Description

Laminated film, optical laminated body, and image display device

The present invention relates to a laminate film, an optical laminate and an image display device.

In an image display device represented by an organic electroluminescence (EL: Electroluminescence) display device, in order to suppress the deterioration of visibility caused by the reflection of external light, it is known to use a circular polarizing plate or the like to A method of improving anti-reflection performance [for example, Japanese Patent Laid-Open No. 2020-134934 (Patent Document 1)]. The circular polarizer is an optical laminate including a linear polarizer and a retardation layer.

[Prior Art Literature]

[Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2020-134934

A circular polarizing plate is usually placed on the viewing side of an image display element such as an organic EL display element. By arranging the circular polarizing plate in this way, it is possible to prevent external light incident on the image display element from being captured by the element. Internally reflected light that is reflected by internal electrodes and the like and emitted to the outside. For optical components such as circular polarizers arranged on the viewing side of image display elements, it is required to adjust the reflection hue according to the requirements while maintaining low reflectivity.

The purpose of the present invention is to provide a laminated film, which is used to form an optical layered body together with a circular polarizing plate by being arranged on the viewing side of a circular polarizing plate, and can maintain the low reflectivity of the optical layered body and adjust the optical layered layer The reflected hue of the body. Another object of the present invention is to provide an optical laminate including the laminated film and a circular polarizing plate, and an image display device including the optical laminate.

The present invention provides the following laminated film, optical laminate and image display device.

[1] A laminated film comprising a substrate film and an optical function layer (A) laminated on the substrate film,

Wherein the visual reflectance Y of the aforementioned laminated film is 9.0% or less, and the a* of the reflection hue is 0.3 to 7.0, and the b* of the reflection hue is -10.0 to 0.

[2] The laminated film according to [1], wherein the optical function layer (A) has a refractive index of not less than 1.55 and not more than 1.68.

[3] The laminated film according to [1] or [2], wherein the difference between the refractive index of the optical function layer (A) and the refractive index of the base film is 0.05 to 0.20.

[4] The laminated film according to any one of [1] to [3], wherein the optical function layer (A) has an optical film thickness of not less than 150 nm and not more than 200 nm.

[5] The laminated film according to any one of [1] to [4], wherein the optical functional layer (A) contains zirconia particles,

In the primary particle size distribution of the aforementioned zirconia particles, the particle size range from 0.1 nm to 15 nm accounts for more than 90%.

[6] The laminated film according to any one of [1] to [5], wherein the base film is a cyclic polyolefin-based resin film, a cellulose ester-based resin film, a polyester-based resin film, or (a base) acrylic resin film.

[7] The laminated film according to any one of [1] to [6], further comprising: a resin layer disposed on the opposite side of the optical function layer (A) to the substrate film.

[8] The laminated film according to any one of [1] to [7], wherein an intermediate layer selected from a primer layer and a hard coat layer is provided between the base film and the optical function layer (A) .

[9] The laminated film according to [8], wherein the interposer contains an ultraviolet absorber.

[10] An optical laminate comprising: the laminate film according to any one of [1] to [9], and a circular polarizing plate.

[11] An image display device comprising the optical laminate described in [10].

The present invention can provide a laminated film, which is used to form a laminated film of an optical laminate together with a circular polarizer by being arranged on the viewing side of a circular polarizer, and can maintain a low reflectance of the optical laminate and adjust the optical layer. The reflective hue of the laminate, and an optical laminate comprising the laminate film and a circular polarizing plate, and an image display device comprising the optical laminate can be provided.

1: laminated film

1a: Optical functional layer (A)

1b: Substrate film

1c: resin layer

1d: Interposer

2: Linear polarizer

2a, 2c: protective film

2b: Linear polarizer

3: phase difference layer

3a: The first retardation layer

3b: The second retardation layer

10: The first bonding layer

20: The second bonding layer

30: The third bonding layer

40: The 4th bonding layer

50: Adhesive layer

60:Separation film

70: protective film

80: 5th bonding layer

90: front panel

100: Image display components

Fig. 1 is a schematic cross-sectional view showing an example of a laminated film according to the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the laminated film of the present invention.

Fig. 3 is a schematic cross-sectional view showing another example of the laminated film of the present invention.

Fig. 4 is a schematic cross-sectional view showing another example of the laminated film of the present invention.

Fig. 5 is a schematic cross-sectional view showing an example of the optical layered body of the present invention.

Fig. 6 is a schematic cross-sectional view showing another example of the optical layered body of the present invention.

Fig. 7 is a schematic cross-sectional view showing another example of the optical layered body of the present invention.

Fig. 8 is a schematic cross-sectional view showing another example of the optical layered body of the present invention.

Fig. 9 is a schematic cross-sectional view showing another example of the optical layered body of the present invention.

Fig. 10 is a schematic cross-sectional view showing an example of an image display device according to the present invention.

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. All the drawings below are presented to assist understanding of the present invention, and the size or shape of each constituent element shown in the drawing is not necessarily consistent with the size or shape of the actual constituent elements.

〈Laminated film〉

The laminated film of the present invention (hereinafter also simply referred to as "laminated film") is a laminated film comprising a base film and an optical function layer (A) laminated on the laminated film. Examples of the layer configuration of the laminated film are shown in FIGS. 1 to 4 .

The laminated film shown in FIG. 1 is composed of a base film 1b and an optical function layer (A) 1a laminated thereon, and the base film 1b is in contact with the optical function layer (A) 1a.

The laminated film shown in FIG. 2 has the same structure as the laminated film shown in FIG. 1 except that it further includes a resin layer 1c disposed on the side opposite to the base film 1b of the optical function layer (A) 1a. The optical function layer (A) 1a is in contact with the resin layer 1c.

The laminated film shown in FIG. 3 has the same structure as the laminated film shown in FIG. 1 except that an intermediary layer 1d is provided between the base film 1b and the optical function layer (A) 1a. The optical function layer (A) 1a is in contact with the interposer 1d, and the interposer 1d is in contact with the base film 1b.

The laminated film shown in FIG. 4 has a resin layer 1c disposed on the side opposite to the base film 1b of the optical function layer (A) 1a, and between the base film 1b and the optical function layer (A) 1a. Except for the interposer 1d, it has the same configuration as the laminated film shown in FIG. 1 . The optical function layer (A) 1a is in contact with the resin layer 1c, the optical function layer (A) 1a is in contact with the interposer 1d, and the interposer 1d is in contact with the base film 1b.

The laminated film is used in combination with a circular polarizer. The term "circular polarizer" includes elliptical polarizers. In this specification, a laminate of a combination of a laminated film and a circular polarizing plate is called an optical laminate. In the optical laminate, the laminated film is laminated on the viewing side of the circular polarizing plate. The term "laminated on the viewing side" means that the circular polarizing plate including the linear polarizing plate and the retardation layer is laminated on the surface of the linear polarizing plate. The laminated film is laminated on the circular polarizing plate such that the base film side faces the circular polarizing plate, for example.

The optical layering system is suitable for image display devices such as organic EL display devices. When it is applied to an image display device, it is such that the laminated film side of the optical laminate becomes the viewing side, that is, the retardation layer side of the optical laminate becomes the image display element (organic EL display element, etc.) side It is arranged on the viewing side of the image display element in such a way.

The following is a detailed description of the optical characteristics of the laminated film, and the constituent elements contained or may be contained in the laminated film.

(1) Optical properties of laminated film and optical functional layer (A)

The apparent reflectance Y of the laminated film is 9.0% or less, a* of the reflection hue is 0.3 to 7.0, and b* of the reflection hue is -10.0 to 0.

According to the laminated film having the above optical characteristics, by laminating it on the viewing side of the circular polarizing plate, it is possible to adjust and control the reflection hue of the optical laminate without being affected by the configuration or retardation characteristics of the circular polarizing plate. In particular, since b* of the reflection hue of the laminated film is -10.0 to 0, the reflected light reflected on the viewing side surface of the optical laminate can be bluish. This is advantageous in making it difficult to observe the color unevenness of the internally reflected light caused by the slight vibration of the reflected hue in the plane of the circular polarizing plate. In the conventional circular polarizing plate, especially when it is composed of a λ/4 layer having inverse wavelength dispersion, internally reflected light is suppressed in a wide visible range, so it is easy to realize black display (making the reflection hue of the circular polarizing plate become neutral). However, there is a problem that the more neutral the reflection hue of the circular polarizer is, the easier it is to see color unevenness. By arranging the laminated film on the viewing side of the circular polarizing plate, this color unevenness can be hardly seen. On the other hand, even if the laminated film is arranged on the viewing side of the circular polarizing plate, the transmitted light (white display) from the image display element will not be changed to a bluish color or the reflectance will not be greatly increased.

According to the present invention, the multilayer film can play the role of adjusting the reflection hue of the optical layered body. Even by adjusting the wavelength dispersion or retardation characteristics of the retardation layer included in the circular polarizing plate, the reflection hue of the circular polarizing plate can be made bluish. However, in this case, another problem arises that the variation of the reflection hue from the oblique direction increases. In addition, the range of the reflection hue that can be adjusted by adjusting the wavelength dispersion or retardation characteristics of the retardation layer of the circular polarizing plate is also limited. According to the method in which the multilayer film plays the role of adjusting the reflection hue of the optical layered body, it is possible to suppress the change of the reflection hue from an oblique direction and make it difficult to see color unevenness.

Moreover, according to the multilayer film of the present invention, since the reflection hue of the optical layered body can be appropriately bluish, it is possible to impart a sense of luxury to the display of an image display device.

The visual reflectance Y of the laminated film is 9.0% or less, preferably 8.5% or less, particularly preferably 8.3% or less, more preferably 8.2% or less, and more preferably 8.0% or less. This can moderately reduce the optical lamination body reflectivity. The visual reflectance Y of the laminated film is usually more than 0%, preferably more than 5.0%, especially preferably more than 5.5%, more preferably more than 6.0%, even more preferably more than 6.5%, and most preferably more than 7.0%. By setting the apparent reflectance Y of the laminated film within this range, the function of adjusting the reflection hue of the optical laminate and maintaining the low reflectance of the optical laminate can be simultaneously achieved.

From the viewpoint of the visibility of the image display device, the reflectance of the optical layered body is preferably 5.5% or less, more preferably 5.4% or less, more preferably 5.3% or less. The reflectance of the optical laminate usually exceeds 0%.

The a* of the reflection hue of the laminated film is not less than 0.3 and not more than 7.0. Since the reflection hue is more suitable for greenish, neutral to slightly reddish, it is preferably not less than 0.5 and not more than 6.0, especially preferably not less than 1.0 and not more than 5.0, and more preferably Above 1.5 and below 4.5. The b* of the reflection hue of the laminated film is -10.0 or more and 0 or less, and in order to make the reflected light reflected on the viewing side surface of the optical laminate moderately bluish, it is preferably -10.0 or more and -0.5 or less , preferably from -9.0 to 1.0, more preferably from -8.0 to 2.0, even more preferably from -8.0 to 3.0.

Since the reflection hue is more suitable to be greenish, neutral to slightly reddish, the a* of the reflection hue of the optical laminate is preferably not less than 0.0 and not more than 2.0, more preferably not less than 0.2 and not more than 1.8, more preferably not less than 0.4 and not more than 1.5, Still more preferably, it is not less than 0.6 and not more than 1.4. The b* of the reflection hue of the optical laminate is preferably -5.0 or more and -2.5 or less, more preferably -4.8 or more and -2.5 or less in order to make the reflected light reflected on the viewing side surface moderately bluish. , more preferably -4.6 or more and -2.6 or less.

The reflectance of the optical layered body, the reflection hue of the laminated film, and the apparent reflectance Y can be measured in accordance with the method described in the item of [Example] described later.

The optical functional layer (A) 1a can be, for example, a high-refractive index layer, a pigment-containing layer (for example, a yellow pigment-containing layer), an alternating multilayer of a high-refractive-index layer and a low-refractive-index layer, a liquid crystal layer, a fluorescent light-emitting layer, or the like. wait combination etc. The high refractive index layer system uses interfacial reflection to achieve the above-mentioned reflective properties. The pigment-containing layer is a layer that contains, for example, a pigment that absorbs yellow light and increases the blueness of reflected light. The alternating multi-layer of high refractive index layer and low refractive index layer uses interfacial reflection on the interface of high refractive index layer and low refractive index layer to realize the above reflection characteristics. The liquid crystal layer uses, for example, the reflection of circularly polarized light brought by cholesteric liquid crystals to achieve the above reflection characteristics. Among them, from the viewpoints of the ease of realization and manufacture of the optical functional layer (A) and laminated film having the above-mentioned optical properties, the viewpoint of the ease of adjustment of the reflection hue of the optical laminate, and the fact that it is preferable that the From the viewpoint of the coloring of transmitted light of the device, the optical function layer (A) 1a is preferably a high refractive index layer.

As a material constituting the high refractive index layer, conventionally known ones can be used, and a layer in which a refractive index imparting agent is dispersed in a binder resin is preferably mentioned. Examples of the refractive index imparting agent include particles made of metal oxides such as zirconia, titanium oxide, tin oxide, zinc oxide, indium tin oxide, indium oxide, aluminum oxide, silicon oxide, yttrium oxide, and antimony oxide. The average particle diameter of the particles is, for example, not less than 0.01 nm and not more than 100 nm, preferably not less than 0.1 nm and not more than 50 nm.

From the viewpoint of the refractive index of the high refractive index layer and the ease of film formation of the layer, the content of the refractive index imparting agent in the high refractive index layer is preferably 10% by mass or more in 100% by mass of the high refractive index layer 90 mass % or less, preferably 20 mass % or more and 80 mass % or less, more preferably 30 mass % or more and 70 mass % or less, still more preferably 40 mass % or more and 60 mass % or less. The refractive index of the high refractive index layer can be adjusted by the content of the refractive index imparting agent in the high refractive index layer. The higher the content of the refractive index imparting agent in the high refractive index layer is, the higher the refractive index of the high refractive index layer can be.

The binder resin may be a cured product of thermoplastic resin or curable resin. The high-refractive-index layer may also have hard-coat properties. In this case, the high-refractive-index layer may be a cured product of a hard-coat-forming composition containing an active energy ray-curable resin such as an ultraviolet-curable resin and a refractive index-imparting agent. to form. active The energy ray curable resins include, for example, (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, epoxy resins, etc., preferably ultraviolet ray hardening resin. The ultraviolet curable resin constituting the binder resin is preferably a (meth)acrylic resin, and is particularly preferably a (meth)acrylic resin containing a structural unit derived from a polyfunctional (meth)acrylic monomer from the viewpoint of curability. Acrylic resin.

The term "(meth)acrylic acid" used in this specification means either acrylic acid or methacrylic acid. "(meth)" in (meth)acrylate etc. has the same meaning.

In order to realize the above-mentioned optical characteristics of the laminated film, the thickness (optical film thickness) of the optical functional layer (A) 1a is preferably from 10 nm to 1000 nm, more preferably from 10 nm to 500 nm, more preferably from 20 nm to 300 nm, and even more preferably It is not less than 40nm and not more than 250nm, particularly preferably not less than 100nm and not more than 200nm, most preferably not less than 150nm and not more than 200nm.

In order to realize the above optical characteristics of the laminated film, the refractive index of the optical functional layer (A) 1a (preferably a high refractive index layer) is preferably from 1.53 to 1.68, more preferably from 1.55 to 1.66, more preferably from 1.58 to 1.64 the following. The refractive index of the optical function layer (A) 1a can be measured in accordance with the method described in the item of the "Example" mentioned later.

In one preferred embodiment, the optical functional layer (A) 1a is a high refractive index layer containing zirconia particles as a refractive index imparting agent. In this embodiment, in order not to hinder the function of suppressing internally reflected light of the circular polarizer, the volume mean diameter (MV) of the zirconia particles is preferably not less than 1 nm and not more than 50 nm, especially preferably not less than 3 nm and not more than 20 nm. For the same reason, in the primary particle size distribution of zirconia particles, the particle size range from 0.1 nm to 15 nm preferably accounts for more than 90%, especially more than 95%. The above-mentioned primary particle size distribution is expressed by measuring the number of zirconia particles.

(2) Substrate film

The base film 1b is a base material supporting the optical function layer (A) 1a. For example, a laminated film including a base film and a high refractive index layer can be formed by applying a composition for forming a high refractive index layer on a base film, and drying and/or curing as necessary.

The thermoplastic resin film mentioned later can be used for a base film. From the viewpoint of thinning, the thickness of the substrate film is usually 100 μm or less, preferably 80 μm or less, particularly preferably 60 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less, and usually 5 μm or more. Preferably it is 10 μm or more.

Among them, the base film is preferably a cyclic polyolefin-based resin film, a cellulose ester-based resin film, a polyester-based resin film, or a (meth)acrylic resin film.

Like the multilayer film shown in Figure 1, when the optical function layer (A) 1a is adjacent to the substrate film 1b, especially in order to realize the above-mentioned optical characteristics of the multilayer film, the refraction of the optical function layer (A) 1a The difference between the index and the refractive index of the substrate film 1b is preferably from 0.05 to 0.20, particularly preferably from 0.07 to 0.18, more preferably from 0.09 to 0.16, still more preferably from 0.09 to 0.14, and may be 0.10 or less.

(3) Resin layer

Like the laminated film shown in FIG. 2 , the laminated film may further include a resin layer 1c disposed on the side opposite to the base film 1b of the optical function layer (A) 1a. Examples of the resin layer 1 c include adhesive layers such as adhesive (Pressure-sensitive Adhesive, also referred to as pressure-sensitive adhesive) layers, hard coat layers, and the like. The bonding layer can be used for laminating the front panel etc. on the viewing side of the optical function layer (A) 1a. Regarding the adhesive layer, the description in "(3) Adhesive layer" described later is cited.

The hard coat layer is, for example, an active energy ray curable resin, preferably a cured layer of an ultraviolet curable resin. Examples of ultraviolet curable resins include (meth)acrylic resins, silicone resins, Polyester-based resins, urethane-based resins, amide-based resins, epoxy-based resins, olefin-based resins, etc. In order to increase the strength, the hard coat may contain additives. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. The hard coat may contain UV absorbers. Examples of the ultraviolet absorber include salicylate-based compounds, benzophenone-based compounds, benzotriazole-based compounds, cyanacrylate-based compounds, nickel complex salt-based compounds, and the like. When there is absorption in the visible light region, since the reflection hue becomes more blue, there is an advantage of lowering the refractive index of the optical function layer. Moreover, the hard-coat layer may be what can transfer from a base film.

(4) Intermediary layer

Like the multilayer film shown in FIG. 3 , the multilayer film may have an intermediary layer 1d between the base film 1b and the optical function layer (A) 1a. Examples of the interposer layer 1d include a primer layer, a hard coat layer, and the like. Like the laminated film shown in FIG. 4, the laminated film may have both the resin layer 1c and the interposer layer 1d.

Examples of resins that form the primer layer include (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, epoxy resins, and olefin resins. wait. The primer layer may also contain additives. The additives are not particularly limited, but for the purpose of improving adhesion and imparting smoothness, examples include adding inorganic fine particles, organic fine particles, or a mixture thereof to the primer layer. The hard coat is cited above.

In the case where the laminated film has an intermediary layer 1d, in order to realize the above-mentioned optical characteristics of the laminated film, the difference between the refractive index of the optical functional layer (A) 1a and the refractive index of the intermediary layer 1d is preferably 0.05 to 0.20, especially preferably 0.05 to 0.20. 0.07 to 0.18, more preferably 0.09 to 0.16, still more preferably 0.09 to 0.14, and may be 0.10 or less.

The interposer 1d may contain an ultraviolet absorber. Examples of ultraviolet absorbers are the same as above. In one embodiment, the intermediary layer 1d is a hard coat layer containing an ultraviolet absorber.

〈Optical laminates〉

The optical layered body (hereinafter also simply referred to as "optical layered body") related to the present invention includes the above-mentioned layered film and a circularly polarizing plate. The circular polarizer includes a linear polarizer and a retardation layer. The optical laminate includes a laminated film, a linear polarizing plate, and a retardation layer in this order. In the optical laminate, the laminated film is laminated on the viewing side of the circular polarizing plate. The term "laminated on the viewing side" means the surface of the linear polarizer laminated on the circular polarizer including the linear polarizer and the retardation layer. The laminated film is laminated on the circular polarizing plate such that the base film side faces the circular polarizing plate, for example.

Fig. 5 is a schematic cross-sectional view showing an example of the optical layered body of the present invention. The optical multilayer system shown in FIG. 5 includes a multilayer film 1 , a linear polarizer 2 and a retardation layer 3 . The laminated film 1 and the linear polarizing plate 2 can be laminated via the first bonding layer 10 , and the linear polarizing plate 2 and the retardation layer 3 can be laminated via the second bonding layer 20 . The laminated film 1 can be laminated on the linear polarizing plate 2 via the first bonding layer 10 so that the base film side faces the linear polarizing plate 2 .

The optical layered body of the present invention can have the following reflection characteristics [a] to [c] because the above-mentioned layered film 1 is disposed on the viewing side of the linear polarizing plate 2.

[a] Reflectance: 5.5% or less, preferably 5.4% or less, particularly preferably 5.3% or less.

[b] a* of reflection hue: 0.0 to 2.0, preferably 0.2 to 1.8, more preferably 0.4 to 1.5, more preferably 0.6 to 1.4.

[c] b* of reflection hue: -5.0 to 2.5, preferably -4.8 to 2.5, particularly preferably -4.6 to 2.6.

(1) Linear Polarizer

The linear polarizer 2 includes a linear polarizer. Linear polarizers have the function of selectively penetrating linearly polarized light in a certain direction from non-polarized light such as natural light. Linear polarizers can be listed: adsorption Stretched film or stretched layer of dichroic dye, hardened product containing polymerizable liquid crystal compound and liquid crystal cured layer of dichroic dye, etc. The laminated film 1 and the linear polarizing plate 2 can be laminated via the first bonding layer 10 .

A linear polarizer that is a stretched film with a dichroic dye adsorbed is usually produced through the steps of uniaxially stretching a polyvinyl alcohol-based resin film, dyeing a polyvinyl alcohol resin film with a dichroic dye such as iodine, etc. A step of absorbing the dichroic dye by means of a vinyl alcohol-based resin film, a step of treating the polyvinyl alcohol-based resin film adsorbed with the dichroic dye with an aqueous solution of boric acid, and washing with water after the treatment with an aqueous solution of boric acid the steps.

The thickness of the stretched film on which the dichroic dye is adsorbed is usually not more than 30 μm, preferably not more than 18 μm, particularly preferably not more than 15 μm. The thickness is usually 1 μm or more, for example, 5 μm or more.

The polyvinyl alcohol-based resin can be obtained by saponifying polyvinyl acetate-based resin. As the polyvinyl acetate resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith can be used. Other monomers that can be copolymerized with vinyl acetate include, for example: unsaturated carboxylic acid-based compounds, olefin-based compounds, vinyl ether-based compounds, unsaturated sulfide-based compounds, and (meth)acrylamide-based compounds with ammonium groups .

The degree of saponification of the polyvinyl alcohol-based resin is generally not less than 85 mol % and not more than 100 mol %, preferably not less than 98 mol %. Polyvinyl alcohol-based resins can be denatured, and polyvinyl formaldehyde and polyvinyl acetal, which have been denatured by aldehydes, can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually not less than 1,000 and not more than 10,000, preferably not less than 1,500 and not more than 5,000.

A linear polarizer having a stretched layer with a dichroic dye adsorbed thereon can usually be produced through the following steps: a step of applying a coating solution containing the above-mentioned polyvinyl alcohol-based resin to the substrate layer; The step of uniaxially stretching the laminate, dyeing the uniaxially stretched laminate with a dichroic dye The step of adsorbing the dichroic dye by the polyvinyl alcohol-based resin layer of the body, the step of treating the layered body on which the dichroic dye is adsorbed with an aqueous solution of boric acid, and washing with water after the treatment with an aqueous solution of boric acid step. The substrate layer may be used as a protective film of the linear polarizer, or may be peeled and removed from the linear polarizer. The material and thickness of the base material layer may be the same as those of the thermoplastic resin film described later.

The linear polarizer 2 may include a protective film laminated on one or both sides of the linear polarizer as a stretched film or a stretched layer having absorbed a dichroic dye. As the protective film, a thermoplastic resin film described later can be used. The linear polarizer and the protective film can be laminated via an adhesive layer (third adhesive layer) described later.

Examples of the thermoplastic resin constituting the thermoplastic resin film include cellulose resins such as cellulose triacetate; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether resins; polyethylene resins; Polycarbonate resin; polyamide resin such as nylon or aromatic polyamide; polyimide resin; polyolefin resin such as polyethylene, polypropylene, ethylene-propylene copolymer; with ring system and norhornene (Norhornene) Cyclic polyolefin resin (also known as norcamphene resin); (meth)acrylic resin; polyarylate resin; polystyrene resin; polyvinyl alcohol resin, etc. Among them, the thermoplastic resin film is preferably a cyclic polyolefin-based resin film, a cellulose ester-based resin film, a polyester-based resin film, or a (meth)acrylic resin film.

From the viewpoint of thinning, the thickness of the thermoplastic resin film is usually 100 μm or less, preferably 80 μm or less, particularly preferably 60 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less, and usually 5 μm or more. Preferably it is 10 μm or more.

A hard coat layer may be formed on the thermoplastic resin film. The hard coat layer may be formed on one side or both sides of the thermoplastic resin film. By providing a hard coat layer, it can be formed as a thermoplastic resin film with improved hardness and scratch resistance. Regarding the hard coat layer, the above description is cited.

The polymerizable liquid crystal compound used in the linear polarizer used to form the liquid crystal cured layer is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. The polymerizable reactive group is to participate in the polymerization reaction The reactive group is preferably a photopolymerizable reactive group. The photopolymerizable reactive group means a group that can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator. Photopolymerizable reactive groups include: vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, oxycyclopropyl (Oxiranyl) Group), Oxetanyl Group, etc. Among them, acryloxy, methacryloxy, ethyleneoxy, oxycyclopropyl and oxetanyl are preferred, and acryloxy is particularly preferred. The type of the polymerizable liquid crystal compound is not particularly limited, and a rod-like liquid crystal compound, a discotic liquid crystal compound, and a mixture thereof can be used. The liquid crystal property of the polymerizable liquid crystal compound can be thermotropic (Thermotropic) liquid crystal or rheotropic (Rheotropic) liquid crystal. Smectic liquid crystal.

In the cured liquid crystal layer, the dichroic dye is dispersed and aligned in the cured product of the polymerizable liquid crystal compound. The dichroic dye used for the linear polarizer of the liquid crystal cured layer preferably has an absorption maximum wavelength in the range of 300 nm to 700 nm. Such dichroic pigments can include, for example: acridine (Acridine) pigments, oxazine (Oxazine) pigments, cyanine (Cyanine) pigments, naphthalene pigments, azo pigments, and anthraquinone (Anthraquinone) pigments. nitrogen pigments. Examples of azo dyes include monoazo dyes, disazo dyes, trisazo dyes, tetrasazo dyes, and stilbene (Stilbene) azo dyes, and are preferably disazo dyes and trisazo dyes. The dichroic dyes may be used alone or in combination of two or more, preferably in combination of three or more. The best combination of three or more azo compounds. A part of the dichroic dye may have a reactive group, or may have liquid crystallinity.

A linear polarizer that is a liquid crystal hardening layer can be coated with a composition for forming a linear polarizer containing a polymerizable liquid crystal compound and a dichroic pigment on an alignment layer formed on a substrate layer, and the polymerizable liquid crystal The compound is formed by polymerization and hardening. It is also possible to coat the composition for forming a linear polarizer on the substrate layer to form a coating film, and stretch the coating film together with the substrate layer to form a linear polarizer. The substrate layer used to form the linear polarizer can also be used as a protective film for the linear polarizer. The material and thickness of the base material layer may be the same as those of the aforementioned thermoplastic resin film.

A composition for forming a linear polarizer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing a linear polarizer using the composition are exemplified in JP-A-2013-37353 and JP-A-2013-33249 The method described in the gazette, Japanese Patent Application Laid-Open No. 2017-83843, etc. In addition to polymerizable liquid crystal compounds and dichroic pigments, the composition for forming linear polarizers may further contain additives such as solvents, polymerization initiators, crosslinking agents, leveling agents, antioxidants, plasticizers, and sensitizers. . These components can be used individually by 1 type or in combination of 2 or more types.

The polymerization initiator that can be contained in the composition for forming a linear polarizer is a compound that can start the polymerization reaction of the polymerizable liquid crystal compound. From the point of view of starting the polymerization reaction at a lower temperature, it is preferably a light Polymerization initiator. Specifically, examples include photopolymerization initiators capable of generating active radicals or acids through the action of light, among which photopolymerization initiators that generate free radicals through the action of light are preferred. The content of the polymerization initiator is preferably from 1 to 10 parts by mass, particularly preferably from 3 to 8 parts by mass, based on 100 parts by mass of the total amount of the polymerizable liquid crystal compound. When it exists in this range, the reaction of a polymeric group will fully progress, and it will become easy to stabilize the alignment state of a liquid crystal compound.

The thickness of the linear polarizer serving as the liquid crystal cured layer is usually not more than 10 μm, preferably not less than 0.5 μm and not more than 8 μm, especially preferably not less than 1 μm and not more than 5 μm.

The linear polarizer 2 may be a laminate of a substrate layer and a linear polarizer that is a cured liquid crystal layer. Alternatively, the substrate layer can be peeled off from the linear polarizer. The linear polarizer 2 including the linear polarizer as a liquid crystal hardening layer may or may not have an alignment layer. The linear polarizer 2 may include: laminated in liquid Protective film on one or both sides of the linear polarizer of crystal hardened layer. The above-mentioned thermoplastic resin film can be used for a protective film. The linear polarizer and the protective film can be laminated via an adhesive layer (third adhesive layer) described later.

For the purpose of protecting the linear polarizer, etc., the linear polarizer that is a liquid crystal cured layer may have an overcoat layer on one or both surfaces. The overcoat layer can be formed, for example, by coating a composition for forming the overcoat layer on a linear polarizer. Examples of materials constituting the overcoat layer include photocurable resins, water-soluble polymers, and the like. Specifically, (meth)acrylic resins, polyvinyl alcohol-based resins, and the like can be used.

The sensitivity correction polarization Py of the linear polarizer is usually above 95%, preferably above 97%, especially above 98%, more preferably above 98.7%, even more preferably above 99.0%, and most preferably above 99.4% It may be more than 99.9%. The sensitivity correction polarization degree Py of the linear polarizer may be 99.999% or less.

The sensitivity correction polarization degree Py can be measured by using a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Co., Ltd.) with a 2-degree field of view (C light source) of "JIS Z 8701" Calculated based on sensitivity correction.

It is advantageous to improve the antireflection function of the optical layered body by improving the sensitivity correction polarization degree Py of the linear polarizer. When the sensitivity correction polarization degree Py is less than 95%, the anti-reflection function may not be exhibited.

The sensitivity correction monomer transmittance Ty of the linear polarizer is usually above 41%, preferably above 41.1%, especially above 41.2%, may be above 42%, and may also be above 42.5%. The sensitivity correction monomer transmittance Ty of the linear polarizer is usually less than 50%, may be less than 48%, may be less than 46%, may be less than 44%, and may be less than 43%. When the light sensitivity correction monomer transmittance Ty is too high, the light sensitivity correction polarization degree Py becomes too low, and the antireflection function of the optical layered body may become insufficient.

Sensitivity correction single transmittance Ty can use a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Co., Ltd.), and use the 2-degree field of view (C light source) of "JIS Z 8701" to analyze the obtained The transmittance is calculated by correcting the sensitivity.

(2) Retardation layer

The optical layer system includes a retardation layer 3 having a first retardation layer 3a. The linear polarizing plate 2 and the first retardation layer 3 a can be laminated via the second bonding layer 20 . The retardation layer 3 may have only the first retardation layer 3a, or may have a laminated structure composed of two or more retardation layers. That is, the retardation layer 3 may include one or more retardation layers different from the first retardation layer 3a. The retardation layer 3 may also have an overcoat layer for protecting its surface, a substrate layer for supporting the retardation layer 3, and the like.

The first retardation layer 3 a is, for example, a λ/4 layer. When the retardation layer 3 includes two retardation layers, the combination of the retardation layers of the layer can be listed as follows: from the side of the linear polarizer 2, the combination of the λ/4 layer and the positive C layer, the λ/2 layer Combination with λ/4 layer, combination of positive C layer and λ/4 layer. The lamination of retardation layers can use the bonding layer (4th bonding layer) mentioned later.

The in-plane retardation value Re(550) of the λ/4 layer at a wavelength of 550nm is usually in the range of 90nm to 220nm, preferably in the range of 100nm to 200nm. The in-plane retardation value Re(550) of the λ/2 layer at a wavelength of 550 nm is preferably in the range of not less than 200 nm and not more than 300 nm. In addition, the retardation value Rth(550) of the positive C layer in the thickness direction at a wavelength of 550nm is usually in the range of -170nm to -10nm, preferably -150nm to -20nm.

From the viewpoint of effectively suppressing the above-mentioned internal reflection, the retardation layer 3 preferably has reverse wavelength dispersion, more preferably the wavelength dispersion α is 0.95 or less, more preferably the wavelength dispersion α is 0.80 to 0.93, and even more preferably The wavelength dispersion α of the series is from 0.80 to 0.90, and the wavelength dispersion α of the ultra-premium series is from 0.80 to 0.88.

The so-called wavelength dispersion α is the ratio of the in-plane retardation value Re(450) at the wavelength of 450nm to the in-plane retardation value Re(550) at the wavelength of 550nm.

Wavelength dispersion α=in-plane retardation value Re(450)/in-plane retardation value Re(550)

The first retardation layer 3a and the other retardation layers may be retardation films formed from the above-mentioned thermoplastic resin film by stretching or the like, or may be liquid crystal cured layers. The liquid crystal cured layer is a cured layer in which a polymerizable liquid crystal compound is polymerized and cured in an aligned state. The retardation layer 3 may include more than one liquid crystal cured layer, or may include two or more layers.

Examples of the polymerizable liquid crystal compound include rod-shaped polymerizable liquid crystal compounds and discotic polymerizable liquid crystal compounds, and a mixture containing one or both of these compounds can be used. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the substrate layer, the optical axis of the polymerizable liquid crystal compound is consistent with the long axis direction of the polymerizable liquid crystal compound. When the discotic polymerizable liquid crystal compound is aligned, the optical axis of the polymerizable liquid crystal compound exists in a direction perpendicular to the disc surface of the polymerizable liquid crystal compound.

In order for the cured liquid crystal layer formed by polymerizing the polymerizable liquid crystal compound to exhibit in-plane retardation, it is only necessary to align the polymerizable liquid crystal compound in an appropriate direction. In the case where the polymerizable liquid crystal compound is rod-shaped, an in-plane retardation is developed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the substrate layer. In this case, the direction of the optical axis and the slow axis The direction is consistent. In the case where the polymerizable liquid crystal compound is discoid, the in-plane phase difference appears by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the substrate layer. In this case, the optical axis and the slow axis Orthogonal. The alignment state of the polymerizable liquid crystal compound can be adjusted through the combination of the alignment layer and the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound is a compound having at least one polymerizable reactive group and having liquid crystallinity. When using 2 or more types of polymerizable liquid crystal compounds together, it is preferable that at least 1 type has 2 or more polymerizable reactive groups in a molecule|numerator. The polymerizable reactive group is a group participating in a polymerization reaction, preferably a photopolymerizable reactive group. The photopolymerizable reactive group means a group that can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator. Examples of photopolymerizable reactive groups are the same as those described above. The liquid crystal property of the polymerizable liquid crystal compound can be thermotropic liquid crystal or rheologically viscous liquid crystal, and when thermotropic liquid crystal is classified by degree of order, it can be nematic liquid crystal or smectic liquid crystal.

The optical laminate may include an alignment layer adjacent to the retardation layer. The alignment layer system has an alignment restriction force, and can align the polymerizable liquid crystal compound in a desired direction. The alignment layer can be a vertical alignment layer that aligns the molecular axis of the polymerizable liquid crystal compound vertically with respect to the substrate layer, or a horizontal alignment layer that aligns the molecular axis of the polymerizable liquid crystal compound horizontally with respect to the substrate layer, or It may be an oblique alignment layer in which the molecular axes of the polymerizable liquid crystal compound are obliquely aligned with respect to the substrate layer.

The thickness of the liquid crystal cured layer may be 0.1 μm or more, may be 0.5 μm or more, may be 1 μm or more, and may be more than 2 μm, and is preferably 10 μm or less, may be 8 μm or less, and may be 5 μm or less.

The cured liquid crystal layer can be formed by applying a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound on the substrate layer and drying it to polymerize the polymerizable liquid crystal compound. The composition for forming a liquid crystal layer can also be coated on an alignment layer formed on a base material layer. The material and thickness of the base material layer may be the same as those of the aforementioned thermoplastic resin film. The substrate layer can be assembled in the optical laminate together with the retardation layer as the liquid crystal cured layer, or the substrate layer can be peeled off and only the liquid crystal cured layer or the liquid crystal cured layer and the alignment layer can be assembled in the optical laminate.

(3) Adhesive layer

Fig. 6 is a schematic cross-sectional view showing another example of the optical layered body of the present invention. The optical laminate system shown in FIG. 6 includes a laminate film 1 , a first bonding layer 10 , a linear polarizer 2 , a second bonding layer 20 , a retardation layer 3 , and an adhesive layer 50 . The retardation layer 3 preferably has reverse wavelength dispersion. The adhesive layer 50 can be laminated on the surface of the optical layered body opposite to the viewing side (laminated film 1 side), and can be used for bonding the optical layered body to an image display element such as an organic EL display element.

In the optical laminate shown in FIG. 6 , a laminate film 1 includes a base film 1b and an optical function layer (A) 1a laminated thereon. The linear polarizer 2 includes a linear polarizer 2b and protective films 2a and 2c laminated on both surfaces with the third bonding layer 30 interposed therebetween. Either one of the protective films 2a and 2c may be omitted. The retardation layer 3 is provided with the 1st retardation layer 3a and the 2nd retardation layer 3b.

The optical laminate system shown in FIG. 6 includes a first retardation layer 3 a and a second retardation layer 3 b, which are bonded by a fourth bonding layer 40 . However, the fourth bonding layer 40 and the second retardation layer 3b can also be omitted.

The thickness of the adhesive layer 50 may be, for example, 250 μm or less, preferably 100 μm or less, particularly preferably 50 μm or less, and more preferably 40 μm or less from the viewpoint of thinning. From the viewpoint of durability, the lower limit of the thickness of the adhesive layer may be, for example, 1 μm or more, preferably 5 μm or more, particularly preferably 10 μm or more.

The adhesive layer 50 can be made of an adhesive composition mainly composed of (meth)acrylic resin, rubber resin, urethane resin, ester resin, silicone resin, and polyvinyl ether resin. constitute. Among them, an adhesive composition using a (meth)acrylic resin excellent in transparency, weather resistance, and heat resistance as a matrix polymer is more suitable. The adhesive composition may be an active energy ray curing type or a thermosetting type.

The (meth)acrylic resin (matrix polymer) used in the adhesive composition is suitable for use: butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, ( methyl) propane A polymer or copolymer of one or more monomers of (meth)acrylate such as 2-ethylhexyl enoate. Among the matrix polymers, those in which polar monomers are copolymerized are preferred. Examples of polar monomers include: (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, (meth)acrylic acid N,N-di Monomers such as methylaminoethyl ester and glycidyl (meth)acrylate having carboxyl groups, hydroxyl groups, amido groups, amino groups, epoxy groups, etc.

Although the adhesive composition may only contain the above-mentioned matrix polymer, it usually further contains a crosslinking agent. Examples of cross-linking agents include metal ions that are divalent or more and form carboxylate metal salts with carboxyl groups, polyamine compounds that form amide bonds between carboxyl groups, and polyepoxides that form ester bonds between carboxyl groups Or polyols, polyisocyanate compounds that form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferable. The adhesive composition may further contain the ultraviolet absorber described in the above description of "<Laminated film> (3) Resin layer".

The active energy ray-curable adhesive composition has the property of being cured by irradiation with active energy rays such as ultraviolet rays or electron beams, and has adhesiveness and can be adhered to films, etc. even before the active energy rays are irradiated. It is attached to the body, hardened by the irradiation of active energy rays and can adjust the nature of the adhesive force. The active energy ray-curable adhesive composition is preferably an ultraviolet-curable adhesive composition. The active energy ray-curable adhesive composition further contains an active energy ray polymerizable compound in addition to a matrix polymer and a crosslinking agent. A photopolymerization initiator, a photosensitizer, etc. may also be contained as needed.

(4) Separation film

As shown in FIG. 7 , the optical layered body may include a separator 60 for protecting the outer surface (the surface opposite to the second phase difference layer 3 b ) of the adhesive layer 50 . The optical layered body shown in FIG. 7 has the same layer configuration as that of the optical layered body shown in FIG. 6 except for the separator 60 . Separator 60 is usually made of: One side is formed by applying a release-treated thermoplastic resin film with a silicone-based, fluorine-based or other release agent, and the release-treated surface is bonded to the adhesive layer 50 .

The thermoplastic resin constituting the separator film 60 is, for example, polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyester-based resins such as polyethylene terephthalate or polyethylene naphthalate, and the like. The thickness of the separator film 60 is, for example, not less than 10 μm and not more than 50 μm.

(5) Protective film

As shown in FIG. 8 , the optical layered body may include a pellicle film 70 laminated on the surface on the side of the layered film 1 . The optical layered body shown in FIG. 8 has the same layer configuration as that of the optical layered body shown in FIG. 7 except for the pellicle 70 . The protective film 70 is composed of, for example, a base film and an adhesive layer laminated thereon. Regarding the adhesive layer, the above description is cited. The resin constituting the base film can be, for example, polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyester-based resins such as polyethylene terephthalate or polyethylene naphthalate , polycarbonate resin and other thermoplastic resins. Polyester-based resins such as polyethylene terephthalate are preferable.

(6) Front panel

As shown in FIG. 9 , the optical laminate may further include a front panel 90 . The front plate 90 is usually disposed on the outermost surface of the viewing side of the optical layered body. For example, the front panel 90 can be laminated on the viewing side surface of the laminated film 1 via the fifth bonding layer 80 . The optical layered body shown in FIG. 9 has the same layer configuration as that of the optical layered body shown in FIG. 7 except for the fifth bonding layer 80 and the front plate 90 .

The material and thickness of the front panel 90 are not limited as long as it is a plate-shaped body through which light can pass. The front panel 90 may be composed of only one layer or may be composed of two or more layers. Examples of the front panel 90 include resin-made plate-shaped objects (such as resin plates, resin sheets, resin films, etc.), glass-made plate-shaped objects (such as glass plates, glass film, etc.), a laminate of a resin-made plate-shaped body and a glass-made plate-shaped body. The front panel may constitute the outermost surface of the display device.

The thickness of the front panel 90 is, for example, 1000 μm or less, preferably 800 μm or less. The thickness is usually at least 10 μm, preferably at least 20 μm.

The resin constituting the resin plate-like body includes, for example: cellulose triacetate, cellulose acetate butyrate, ethylene-vinyl acetate copolymer, cellulose propionate, cellulose butyrate, cellulose acetate propionate, polyester Esters, polystyrene, polyamides, polyetherimides, poly(meth)acrylic acids, polyimides, polyethers, polyethers, polyethylenes, polypropylenes, polymethylpentenes, polyvinyl chlorides , polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether ketone, polymethyl methacrylate, polyethylene terephthalate, polyethylene terephthalate Thermoplastic resins such as butylene glycol ester, polyethylene naphthalate, polycarbonate, and polyamideimide. These thermoplastic resins can be used individually or in mixture of 2 or more types. From the standpoint of improving strength and transparency, the resin plate-shaped body is preferably a thermoplastic resin film formed of polyimide, polyamide, polyamideimide, or the like.

From the viewpoint of hardness, the front panel 90 may be a thermoplastic resin film provided with a hard coat layer. The hard coat layer may be formed on one surface of the thermoplastic resin film, or may be formed on both surfaces. By providing a hard coating, the hardness and scratch resistance can be improved. Regarding the hard coat layer, the above description is cited.

When the front panel 90 is a glass plate, tempered glass for displays is suitably used for the glass plate. The thickness of the glass plate may be, for example, not less than 10 μm and not more than 1000 μm, or may be not less than 10 μm and not more than 800 μm. By using a glass plate, a front panel having excellent mechanical strength and surface hardness can be constituted.

The front panel 90 is preferably highly rigid, for example, the Young's modulus is 70 GPa or more, and may be 80 GPa or more. The Young's modulus of the front panel 90 is usually 100 GPa or less. Young's modulus can be measured by the following method. Use a super cutter to cut out the measurement of the panel 90 before the long side 110mm x short side 10mm Custom samples. Next, the upper and lower grips of the tensile testing machine (manufactured by Shimadzu Corporation, Autograph AG-Xplus testing machine) clamped the two ends of the longitudinal direction of the above-mentioned measurement sample so that the interval between the grips became 5 cm, and heated at temperature Under an environment of 23°C and a relative humidity of 55%, stretch the sample in the longitudinal direction at a tensile speed of 4 mm/min, and calculate the temperature from the slope of the straight line between 20 and 40 MPa in the stress-strain curve obtained Young's modulus at 23°C and 55% relative humidity.

When the multilayer film 1 includes a high refractive index layer, and the front panel 90 is arranged on the surface on the viewing side through the fifth bonding layer 80, from the viewpoint that the above-mentioned color unevenness is difficult to be seen, the fifth layer The refractive index of the bonding layer 80 is preferably not less than 1.45 and not more than 1.51, especially preferably not less than 1.46 and not more than 1.50. The refractive index of the front panel 90 is preferably not less than 1.49 and not more than 1.52, and is more preferably not less than 1.50 and not more than 1.52. The fifth bonding layer 80 is preferably an adhesive layer.

When the optical laminate is applied to an image display device, the front panel 90 not only has the function of protecting the front (screen) of the image display device (as a viewing window film), but also serves as a touch sensor function, blue light filter function, viewing angle adjustment function, etc.

(7) Adhesive layer

The optical laminate may include an adhesive layer for bonding two layers (or films). Examples of the bonding layer include: the first bonding layer 10 bonding the laminated film 1 and the linear polarizing plate 2, the second bonding layer 20 bonding the linear polarizing plate 2 and the retardation layer 3, bonding the linear polarizing plate 2b and The third bonding layer 30 for the protective films 2a and 2c, the fourth bonding layer 40 for bonding the first retardation layer 3a and the second retardation layer 3b, and the fifth bonding layer 80 for bonding the front panel 90 (It can be regarded as the resin layer 1c which the laminated film 1 has), etc.

The bonding layer is an adhesive layer composed of an adhesive composition or an adhesive layer composed of an adhesive composition. Regarding the adhesive composition and the adhesive layer, the description in (3) above is cited.

Examples of the adhesive composition include water-based adhesives, active energy ray-curable adhesives, and the like. Examples of water-based adhesives include polyvinyl alcohol-based resin aqueous solutions, water-based two-component urethane-based emulsified adhesives, and the like. Active energy ray-curable adhesives are adhesives that are cured by irradiating active energy rays such as ultraviolet rays. Examples include adhesives containing polymerizable compounds and photopolymerizable initiators, adhesives containing photoreactive resins, Adhesives containing adhesive resins and photoreactive crosslinking agents, etc. Examples of the polymerizable compound include: photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers; monomeric oligomers, etc. Examples of the photopolymerization initiator include compounds containing substances that generate active species such as neutral radicals, anion radicals, and cationic radicals by irradiation with active energy rays such as ultraviolet rays.

The thickness of the bonding layer composed of the adhesive composition may be, for example, 0.1 μm or more, preferably 0.5 μm or more, 1 μm or more, or 2 μm or more, and may be 100 μm or less, 50 μm or less, 25 μm or less, 15 μm or less, or 5 μm or less.

The two facing surfaces bonded via the bonding layer can be pre-treated with corona treatment, plasma treatment, flame treatment and other surface activation treatments.

<Image display device>

The image display device of the present invention includes the optical layered body of the present invention, and an image display element (organic EL display element, etc.). The optical laminate system is arranged on the viewing side of the image display element. The optical laminate can be bonded to the image display element using the adhesive layer 50 .

Fig. 10 is a schematic cross-sectional view showing an example of an image display device according to the present invention. In FIG. 10, the optical layered body shown in FIG. 9 is used as an example of the optical layered body. The optical laminate system is bonded to the image display element 100 using the adhesive layer 50 . The front panel 90 is laminated on the surface of the optical layered body opposite to the adhesive layer 50 (the outermost surface on the viewing side) via the fifth bonding layer 80 .

The image display device is not particularly limited, and examples thereof include image display devices such as organic electroluminescence (organic EL) display devices, inorganic electroluminescence (inorganic EL) display devices, liquid crystal display devices, and field emission display devices.

The image display device can be used as portable devices such as smart phones and tablet computers, TVs, digital photo frames, electronic signboards, measuring devices or measuring instruments, office devices, medical devices, computer devices, etc.

[Example]

Hereinafter, the present invention will be described more specifically by showing examples and comparative examples, but the present invention is not limited to these examples.

[determination]

(1) Visual reflectance Y and reflection hue (a* and b*) of the laminated film

First, the reflectance in the visible light region was measured using a spectrophotometer "MPC-2200" manufactured by Shimadzu Corporation. At the time of measurement, a black acrylic plate ("Kanase Lite 1410" manufactured by Kanase Co., Ltd.) was attached to the inner side of the measurement surface through an adhesive layer. The visual reflectance Y and reflection hue (a* and b*) were calculated from the obtained reflectance spectrum. The visual reflectance was calculated by multiplying the obtained reflectance Y by the visual sensitivity coefficient.

(2) Optical film thickness and refractive index of optical functional layer (A) (@550nm)

First, the reflectance of the laminated film in the visible light region was measured using a spectrophotometer "MPC-2200" manufactured by Shimadzu Corporation. At the time of measurement, a black acrylic plate ("Kanase Lite 1410" manufactured by Kanase Co., Ltd.) was attached to the inner side of the measurement surface through an adhesive layer. For the obtained reflectance spectrum, the spectral fitting is carried out in accordance with the reflectance at the wavelength of 550nm in the spectrum calculated from the calculation formula of the thin film interference spectrum, and the refractive index and optical film thickness of the optical functional layer are calculated. .

(3) Retardation characteristics of the retardation layer

The retardation characteristics of the retardation layer were measured using "KOBRA-WPR" manufactured by Oji Scientific Instruments Co., Ltd.

<Example 1>

(1) Fabrication of laminated film

(1-1) Preparation of high refractive index layer forming composition

A photopolymerization initiator ("Irgacure 184" manufactured by BASF Corporation) and a dilution solvent (MEK/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. An ultraviolet curable resin ("KAYARAD-DPHA" manufactured by Nippon Kayaku Co., Ltd.) was added thereto and stirred. Then, a zirconia particle dispersion ("ZRMIBK15WT%-P03" manufactured by CIK-Nano Tek Co., Ltd., solid content 15% by mass, average primary particle diameter 7.8nm) was added and stirred to prepare a composition for forming a high refractive index layer.

As for the zirconia particle dispersion liquid, the primary particle size distribution was measured using "MT3300EX" manufactured by Microtrac Co., Ltd. As a result, the ratio of the particle size range from 0.1 nm to 15 nm in the whole was 99.56%.

(1-2) Production of laminated film

On a cellulose triacetate film (refractive index: 1.49; hereinafter also referred to as "TAC film") as a substrate film with a thickness of 40 μm, the high refractive index prepared in (1-1) above was applied using a bar coater. The composition for layer formation was prepared by drying and irradiating with ultraviolet rays to produce a laminated film composed of a base film and an optical function layer (high refractive index layer) having an optical film thickness shown in Table 1. Table 1 shows the refractive index of the optical function layer together.

In addition, the visual reflectance Y and reflection hue of the laminated film are shown in Table 1 together.

(2) Fabrication of optical laminates

(2-1) Attaching the front panel to the laminated film

An adhesive layer (refractive index: 1.49) was laminated on the optical functional layer of the laminated film obtained in (1) above. Laminate the non-alkali glass plate (refractive index 1.51) on the adhesive layer to obtain a laminated film with a front panel (glass plate) consisting of glass plate/adhesive layer/optical function layer/substrate film.

(2-2) Production of linear polarizing plate

By dry stretching, a polyvinyl alcohol-based resin film with a thickness of 20 μm (average degree of polymerization about 2400, saponification degree of 99.9 mol% or more) is stretched about 5 times in the longitudinal direction, and then dipped while maintaining the tension After 1 minute in pure water at a temperature of 60° C., it was immersed in an aqueous solution at a temperature of 28° C. at a mass ratio of iodine/potassium iodide/water of 0.05/5/100 for 60 seconds. Then, it was immersed in an aqueous solution at a temperature of 72° C. at a mass ratio of potassium iodide/boric acid/water of 8.5/8.5/100 for 300 seconds. Then, after washing with pure water at a temperature of 26° C. for 20 seconds, drying treatment was performed at a temperature of 65° C. to obtain a linear polarizer with a thickness of 8 μm in which iodine was adsorbed and aligned on a polyvinyl alcohol-based resin film.

A polyvinyl alcohol aqueous solution was prepared by dissolving 3 parts by mass of carboxy-denatured polyvinyl alcohol ["KL-318" manufactured by Kuraray Co., Ltd.] with respect to 100 parts by mass of water. A water-soluble polyamide epoxy resin ("Sumirez Resin 650 (30)" manufactured by Tianoka Chemical Industry Co., Ltd., solid content concentration: 30% by mass) was mixed in a ratio of 1.5 parts by mass relative to 100 parts by mass of water. The resulting aqueous solution was used to obtain a water-based adhesive.

The water-based adhesive obtained above was coated on one surface of the linear polarizer obtained above, and a cyclic polyolefin-based resin film (hereinafter also referred to as "HC layer") having a hard coat layer (hereinafter also referred to as "HC layer") was laminated. Also called "COP film"), and then apply the water-based adhesive obtained above on the other side of the linear polarizer, laminate the TAC film and dry it at 80°C for 5 minutes, thereby obtaining a linear polarizer Linear polarizer with protective film on both sides. The layer structure of the linear polarizer is HC layer/COP film/water system Adhesive layer/linear polarizer/water-based adhesive layer/TAC film. A protective film with an adhesive layer on the base film is laminated on the HC layer of the linear polarizing plate to obtain a linear polarizing plate with protective film (hereinafter also referred to as "linear polarizing plate with PF").

(2-3) Fabrication of retardation laminated body

Form an alignment layer on the first substrate layer made of transparent resin, and apply a composition for forming a liquid crystal layer containing a rod-shaped nematic polymerizable liquid crystal compound to produce a first phase with a first substrate layer Poor layer. The first retardation layer is a λ/4 layer. The thickness of the first retardation layer was 2 μm. The wavelength dispersion α [in-plane retardation value Re(450)/in-plane retardation value Re(550)] of the first retardation layer was 0.85, and Re(550) was 142 nm. The details are shown below.

[Preparation of Alignment Layer Forming Composition]

The photo-alignment material with the following structure (weight average molecular weight: 50000, m:n=50:50) was manufactured according to the method described in Japanese Patent Laid-Open No. 2021-196514. 2 parts by mass of the photo-alignment material and 98 parts by mass of cyclopentanone (solvent) were mixed as components. The resulting mixture was stirred at 80° C. for 1 hour to prepare a composition for forming an alignment layer.

Photoalignment material:

[Manufacture of nematic polymerizable liquid crystal compound]

A polymerizable liquid crystal compound (A1) and a polymerizable liquid crystal compound (A2) having the structures shown below were prepared, respectively. The polymerizable liquid crystal compound (A1) is prepared in the same way as the method described in Japanese Patent Laid-Open No. 2019-003177 prepare. The polymerizable liquid crystal compound (A2) was prepared in the same manner as the method described in JP-A-2009-173893.

Polymeric liquid crystal compound (A1):

Polymeric liquid crystal compound (A2):

A solution was obtained by dissolving 1 mg of the polymerizable liquid crystal compound (A1) in 10 mL of chloroform. The obtained solution was put into a measurement unit with an optical path length of 1 cm as a measurement sample, and then the measurement sample was set in an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation "UV-2450") and Measure the absorption spectrum. The wavelength of maximum absorption was read from the obtained absorption spectrum. As a result, the maximum absorption wavelength λ max in the wavelength range of 300 to 400 nm was 356 nm.

[Preparation of the composition for forming the first retardation layer]

A polymerizable liquid crystal compound (A1) and a polymerizable liquid crystal compound (A2) were mixed at a mass ratio of 93:7 to obtain a mixture. With respect to 100 parts by mass of the obtained mixture, 0.1 part by mass of a leveling agent "BYK-361N" (manufactured by BM Chemie Co., Ltd.) and "Irgacure OXE-03" (manufactured by BASF JAPAN Co., Ltd.) as a photopolymerization initiator were added 3 parts by mass. Then, N-methyl-2-pyrrolidone (NMP:N-methyl-2-pyrrolidone) was added so that the solid content concentration might become 13 mass %. This mixture was stirred at a temperature of 80° C. for 1 hour to prepare a first composition for retardation layer formation.

[Production of the first retardation layer]

The composition for forming an alignment layer was coated on a biaxially stretched polyethylene terephthalate (PET) film (Diafoil, manufactured by Mitsubishi Plastics Co., Ltd.) as a first base material layer with a bar coater. ). After drying the obtained coating film at 120 degreeC for 2 minutes, it cooled to room temperature and formed a dry coating film. Then, an alignment layer was obtained by irradiating 100 mJ of polarized ultraviolet rays (based on 313 nm) using a UV irradiation device (SPOT CURE SP-9; manufactured by Ushio Co., Ltd.). The film thickness of the alignment layer measured using an ellipsometer M-220 manufactured by JASCO Corporation was 100 nm.

The said 1st composition for retardation layer formation was apply|coated on the obtained alignment layer with the bar coater, and the coating film was formed. After heat-drying this coating film at 120 degreeC for 2 minutes, it cooled to room temperature and obtained the dry coating film. Next, using a high-pressure mercury lamp ("Unicure VB-15201BY-A" manufactured by Ushio Co., Ltd.), irradiate the above-mentioned dried film with ultraviolet light at an exposure dose of 500mJ/cm ² (365nm basis) under a nitrogen atmosphere to form: Polymerization The first retardation layer hardened by the liquid crystal compound in the state of being aligned in the horizontal direction relative to the surface of the substrate, and the first substrate layer/alignment layer/first retardation layer (horizontally aligned liquid crystal cured film) composed of the first retardation layer with the first substrate layer. The film thickness of the first retardation layer measured using a laser microscope LEXT OLS4100 manufactured by Olympus Co., Ltd. was 2.0 μm.

Moreover, the 2nd retardation layer with the 2nd base material layer was produced by the following method.

[Preparation of the composition for forming the second retardation layer]

100 parts by mass of a polymerizable liquid crystal compound Paliocolor LC242 (manufactured by BASF JAPAN Co., Ltd.), 0.1 parts by mass of a leveling agent "BYK-361N" (manufactured by BYK-Chemie Co., Ltd.), and a photopolymerization initiator "Omnirad 907" (manufactured by IGM Resin B.V. Company system) 2.5 parts by mass. Then add propylene glycol 1-monomethyl ether 400 parts by mass of 2-acetate (PGME), and the obtained mixture were stirred at a temperature of 80° C. for 1 hour to prepare a second composition for retardation layer formation.

Polymeric liquid crystal compound LC242:

[Preparation of Alignment Layer Forming Composition]

2-Butoxyethanol was added to Sunever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), a commercially available alignment polymer, so that the solid content became 1% by mass, to obtain a composition for forming an alignment layer.

[Production of the second retardation layer]

Cyclic olefin polymer (COP) (manufactured by Zeon Japan Co., Ltd., ZF14) was used as the second substrate layer, and one side of it was electrically energized using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.). After halo treatment, the composition for forming an alignment layer was coated on the surface using a bar coater, and dried at 90° C. for 1 minute. The film thickness of the obtained alignment layer was measured with a laser microscope and found to be 30 nm. Next, the composition for forming the second retardation layer was coated on the alignment layer using a bar coater, and dried at 90° C. for 1 minute, and then was dried using a high-pressure mercury lamp (Ushio Co., Ltd. “Unicure VB-15201BY-A ”), under a nitrogen atmosphere, irradiate the above-mentioned dry film with ultraviolet rays at an exposure dose of 1000mJ/cm ² (365nm basis), thereby obtaining a second retardation layer with a second substrate layer. The film thickness was measured with a laser microscope, and the film thickness of the second retardation layer was 450 nm. The in-plane retardation value was measured using KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. As a result, Re(550)=1nm and Rth(550)=-75nm. Therefore, the second retardation layer with the second substrate layer has optical characteristics represented by nx≒ny<nz. Since the retardation value of COP at the wavelength of 550nm is approximately 0, it will not affect the optical characteristics.

Mix the cation-curable ingredients shown below to prepare UV-curable adhesive.

3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Co., Ltd.): 70 parts by mass

Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase Chemtex Co., Ltd.): 20 parts by mass

2-Ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase Chemtex Co., Ltd.): 10 parts by mass

Cationic polymerization initiator (trade name: CPI-100, 50% solution, manufactured by Sun Apro Co., Ltd.): 4.5 parts by mass (substantial solid content: 2.25 parts by mass)

1,4-diethoxynaphthalene: 2.0 parts by mass

Corona treatment was applied to the retardation layer side of the first retardation layer with the first substrate layer and the retardation layer side of the second retardation layer with the second substrate layer, respectively. Apply the prepared ultraviolet curable adhesive on one corona-treated surface, and bond the first retardation layer with the first base layer and the second retardation layer with the second base layer. Ultraviolet rays are irradiated from the second base layer side to cure the ultraviolet curable adhesive to form an adhesive layer. The thickness of the cured ultraviolet curable adhesive layer was 1.5 μm.

(2-4) Production of optical laminates

An adhesive layer containing an ultraviolet absorber was bonded to the surface on the TAC film side of the linear polarizing plate obtained in (2-2) above. Next, the first base material layer of the retardation laminate obtained in (2-3) above was peeled off, and the adhesive laminated layer containing the ultraviolet absorber bonded to the above-mentioned linear polarizing plate was exposed to out of the alignment layer, and the production of circular polarizing plate. The reflection hue and reflectance described below were measured for the obtained circular polarizing plate. As a result, reflectance Y: 5.2%, reflection hue a*: -0.1, b*: -1.6.

Then, the laminated film with a front panel obtained in (2-1) above was laminated on the HC layer of the linear polarizing plate of the circular polarizing plate via an adhesive layer to obtain an optical laminate. At this time, the laminated film with the front panel is bonded to the linear polarizing plate with the substrate film side interposed therebetween.

(3) Measurement and evaluation of reflection hue and reflectance Y of optical laminates

The reflection hue a* and b* and the reflectance Y of the optical layered body obtained in said (2) were measured using "Cm2600d" manufactured by Konica Minolta. The results are shown in Table 1. During the measurement, a glass plate (thickness 0.7 mm, "Eagle XG" manufactured by Corning Co., Ltd.) was bonded to the surface of the optical laminate on the opposite side to the light incident surface through an adhesive layer (the front and rear of the optical laminate) The panel is the opposite side), and then the front panel faces up, and the optical laminate with the glass plate obtained above is placed on a reflective plate (reflectivity: 96% or more, diffuse reflectance: 9% or less), On the other hand, the measurement was performed in a state formed into a layer configuration of reflective plate/air/glass plate/optical laminate. The reflection hue of the optical layered body was evaluated according to the following references. The results are shown in Table 1.

A: a* is not less than 0.0 and not more than 2.0, and b* is not less than -5.0 and not more than -2.5.

B: a* or b* is out of the above range.

The reflectance Y of the optical layered body was evaluated in accordance with the following references. The results are shown in Table 1.

A: The reflectance Y is 5.5% or less.

B: The reflectance Y exceeds 5.5%.

<Embodiments 2 to 4>

(1) Fabrication of laminated film

Except that the optical film thickness of the optical function layer (high refractive index layer) is set as shown in Table 1, other laminated films are produced in the same manner as in Example 1 (using the same high refractive index layer as in Example 1) forming composition). Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

<Comparative example 1>

(1) Fabrication of laminated film

(1-1) Preparation of high refractive index layer forming composition

0.4 parts by mass of a photopolymerization initiator ("Irgacure 184" manufactured by BASF Corporation) and 29.6 parts by mass of a dilution solvent (MEK/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. 70.0 parts by mass of an ultraviolet curable resin ("KAYARAD-DPHA" manufactured by Nippon Kayaku Co., Ltd.) was added thereto and stirred to prepare a composition for forming a high refractive index layer.

(1-2) Production of laminated film

On a TAC film (refractive index: 1.49) with a thickness of 40 μm as a base film, the composition for forming a high refractive index layer prepared in (1-1) above was coated with a bar coater, dried and irradiated with ultraviolet rays. , A laminated film composed of a substrate film and an optical functional layer (high refractive index layer) having an optical film thickness (5 μm) shown in Table 1 was produced. Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

(Comparative example 2>

(1) Fabrication of laminated film

(1-1) Preparation of high refractive index layer forming composition

0.3 parts by mass of a photopolymerization initiator ("Irgacure 184" manufactured by BASF Corporation) and 44.6 parts by mass of a dilution solvent (MEK/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. 2.0 parts by mass of an ultraviolet curable resin ("KAYARAD-DPHA" manufactured by Nippon Kayaku Co., Ltd.) was added thereto and stirred. Then, 53.4 parts by mass of zirconia particle dispersion ("ZRMIBK15WT%-P03" manufactured by CIK-Nano Tek Co., Ltd., solid content 15% by mass, average primary particle diameter 7.8nm) was added and stirred to prepare a composition for forming a high refractive index layer. thing.

(1-2) Production of laminated film

On a TAC film (refractive index: 1.49) with a thickness of 40 μm as a base film, the composition for forming a high refractive index layer prepared in (1-1) above was coated with a bar coater, dried and irradiated with ultraviolet rays. , A laminated film composed of a substrate film and an optical functional layer (high refractive index layer) having an optical film thickness shown in Table 1 was produced. Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

<Comparative Examples 3 to 5>

(1) Fabrication of laminated film

Except that the optical film thickness of the optical function layer (high refractive index layer) is set as shown in Table 1, other laminated films were produced in the same manner as in Comparative Example 2 (using the same high refractive index layer as in Comparative Example 2) forming composition). Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

<Comparative example 6>

(1) Fabrication of laminated film

(1-1) Preparation of high refractive index layer forming composition

0.4 parts by mass of a photopolymerization initiator ("Irgacure 184" manufactured by BASF Corporation) and 17.6 parts by mass of a dilution solvent (MEK/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. 2.9 parts by mass of an ultraviolet curable resin ("KAYARAD-DPHA" manufactured by Nippon Kayaku Co., Ltd.) was added and stirred. Then, 79.1 parts by mass of zirconia particle dispersion ("ZRMIBK15WT%-P03" manufactured by CIK-Nano Tek Co., Ltd., solid content 15% by mass, average primary particle diameter 7.8nm) was added and stirred to prepare a composition for forming a high refractive index layer. thing.

(1-2) Production of laminated film

On a TAC film (refractive index: 1.49) with a thickness of 40 μm as a base film, the composition for forming a high refractive index layer prepared in (1-1) above was coated with a bar coater, dried and irradiated with ultraviolet rays. , A laminated film composed of a substrate film and an optical functional layer (high refractive index layer) having an optical film thickness shown in Table 1 was produced. Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

<Comparative Examples 7 to 8>

(1) Fabrication of laminated film

Except that the optical film thickness of the optical function layer (high refractive index layer) is set as shown in Table 1, other laminated films were produced in the same manner as in Comparative Example 6 (using the same high refractive index layer as in Comparative Example 6) forming composition). Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

<Comparative Example 9>

(1) Fabrication of laminated film

(1-1) Preparation of high refractive index layer forming composition

0.4 parts by mass of a photopolymerization initiator ("Irgacure 184" manufactured by BASF Corporation) and 29.6 parts by mass of a dilution solvent (MEK/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. 70.0 parts by mass of an ultraviolet curable resin ("KAYARAD-DPHA" manufactured by Nippon Kayaku Co., Ltd.) was added thereto and stirred to prepare a composition for forming a high refractive index layer.

(1-2) Preparation of composition for forming low refractive index layer

0.2 parts by mass of a photopolymerization initiator ("Irgacure 127" manufactured by BASF Corporation) and 91.1 parts by mass of a dilution solvent (methyl isobutyl ketone/acetonitrile mass ratio=7/3) were mixed and stirred. 3.1 parts by mass of ultraviolet curable resin ("KAYARAD-PET-30" manufactured by Nippon Kayaku Co., Ltd.), 5.5 parts by mass of hollow silica particles (solid content: 20% by mass, average primary particle diameter: 60 nm), and leveling agent ( Made by Dainichi Seika Co., Ltd. "Seikabeam 10-28 (MB)") 0.1 parts by mass was added here and stirred to prepare a composition for forming a low refractive index layer.

(1-3) Fabrication of laminated film

On a TAC film (refractive index: 1.49) with a thickness of 40 μm as a base film, the composition for forming a high refractive index layer prepared in (1-1) above was coated with a bar coater, dried and irradiated with ultraviolet rays. , A high-refractive-index layer having an optical film thickness (3 μm) shown in Table 1 was produced. Next, using a bar coater, apply the low-refractive-index layer-forming composition prepared in (1-2) above on the high-refractive-index layer, dry and irradiate with ultraviolet rays to form a low-refractive-index layer, and produce A laminated film consisting of a base film and optical functional layers (high refractive index layer and low refractive index layer) having the optical film thicknesses shown in Table 1. Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

(Comparative Example 10>

(1) Fabrication of laminated film

Except that the optical film thickness of the low refractive index layer was set as shown in Table 1, a laminated film was produced in the same manner as in Comparative Example 9 (using the same composition for forming a high refractive index layer as in Comparative Example 9 and composition for forming a low refractive index layer). Table 1 shows the refractive index of the optical function layer and the apparent reflectance Y and reflection hue of the laminated film.

(2) Production of optical laminates and measurement and evaluation of reflection hue and reflectance Y

Except for using the multilayer film obtained in the above (1), an optical layered body was fabricated in the same manner as in Example 1, and the measurement and evaluation of reflection hue and reflectance Y were performed. The results are shown in Table 1.

[Table 1]

In Table 1, the numerical value of the optical film thickness of the optical functional layer in Comparative Examples 9 and 10 represents the optical film thickness of the high refractive index layer/the optical film thickness of the low refractive index layer. The numerical value of the refractive index of the optical functional layer in Comparative Examples 9 and 10 represents the refractive index of the high refractive index layer/the refractive index of the low refractive index layer.

1a: Optical functional layer (A)

1b: Substrate film

Claims (11)

A laminated film comprising a substrate film and an optical function layer (A) laminated on the substrate film, Wherein the visual reflectance Y of the aforementioned laminated film is 9.0% or less, and the a* of the reflection hue is 0.3 to 7.0, and the b* of the reflection hue is -10.0 to 0. The laminated film according to Claim 1, wherein the refractive index of the optical function layer (A) is not less than 1.55 and not more than 1.68. The laminated film according to claim 1 or 2, wherein the difference between the refractive index of the optical function layer (A) and the refractive index of the base film is 0.05 to 0.20. The laminated film according to claim 1 or 2, wherein the optical film thickness of the optical function layer (A) is not less than 150nm and not more than 200nm. The laminated film according to claim 1 or 2, wherein the optical function layer (A) contains zirconia particles, In the primary particle size distribution of the aforementioned zirconia particles, the particle size range from 0.1 nm to 15 nm accounts for more than 90%. The laminated film according to claim 1 or 2, wherein the base film is a cyclic polyolefin resin film, a cellulose ester resin film, a polyester resin film, or a (meth)acrylic resin film. The laminated film according to claim 1 or 2, further comprising: a resin layer arranged on the side opposite to the substrate film of the optical function layer (A). The laminated film according to claim 1 or 2, wherein an intermediary layer selected from a primer layer and a hard coat layer is provided between the base film and the optical function layer (A). The laminated film according to claim 8, wherein the interposer contains an ultraviolet absorber. An optical laminate comprising: the laminate film described in claim 1 or 2, and a circular polarizing plate. An image display device comprising the optical laminate described in Claim 10.

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