CN116515457A

CN116515457A - Pressure-sensitive adhesive layer, method for producing same, pressure-sensitive adhesive sheet, optical film with pressure-sensitive adhesive layer, and image display device

Info

Publication number: CN116515457A
Application number: CN202310382624.3A
Authority: CN
Inventors: 形见普史; 野中崇弘
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2018-05-11
Filing date: 2019-04-10
Publication date: 2023-08-01
Also published as: CN112074580A; JP2019196468A; JP2023059986A; WO2019216096A1; KR20210009322A; TW201946995A; SG11202011147XA

Abstract

The invention relates to an adhesive layer, a method for producing the same, an adhesive sheet, an optical film with the adhesive layer, and an image display device. The adhesive layer of the present invention has a first face and a second face on opposite sides of the first face, wherein in the adhesive layer, a substrate of the entire adhesive layer is formed from an adhesive composition containing a base polymer, the first face has a first refractive index based on the adhesive composition, and the second face has a second refractive index lower than the first refractive index of the first face. The adhesive layer of the present invention can effectively suppress internal reflection and has good adhesion even when applied to an optical member having a low refractive index such as an antireflection film, a light diffusion film, a prism film, a light guide film, a lens film, a fresnel lens, a lenticular lens, or a microlens film.

Description

Pressure-sensitive adhesive layer, method for producing same, pressure-sensitive adhesive sheet, optical film with pressure-sensitive adhesive layer, and image display device

The present application is a divisional application of chinese patent application with application number 201980030221.4, with application date 2019, 4, 10.

Technical Field

The present invention relates to an adhesive layer and a method for producing the same. The present invention also relates to an adhesive sheet having the adhesive layer and an optical film having the adhesive layer. The present invention also relates to an image display device using the adhesive layer or the optical film with an adhesive layer.

Background

For example, in display devices such as liquid crystal display devices and organic Electroluminescence (EL) display devices, an adhesive composition is used to bond a transparent cover member such as a polarizing film, a retardation film, and a cover glass, and other various optical films to other optical films. In this way, by disposing the adhesive layer between the two optical films, an optical film laminate having the two optical films is formed. The optical film laminate having such a structure is disposed in a display device such that one side of the optical film is a visible side, for example. This structure has the following problems: when external light is incident from the optical film on the visible side, the incident light is reflected at the interface of the adhesive layer and the optical film on the non-visible side and returns to the visible side. This problem becomes particularly remarkable when the incident angle of external light is large.

On the other hand, a light diffusing adhesive composition containing light diffusing fine particles and having a (meth) acrylic polymer as a base polymer is proposed for use in a backlight unit of an image display device (patent document 1).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2014-224964

Disclosure of Invention

Problems to be solved by the invention

The problems described above are considered to be caused by the refractive index difference between the adhesive layer and the adherend. For example, between the adhesive layer and an optical member (for example, an antireflection film, a light diffusion film, a light guide film, a prism film, a lens film, a fresnel lens, a lenticular lens, or a microlens film) using a material of low refractive index such as a fluorine-containing resin, polysiloxane, low refractive inorganic particles, a porous material, a hollow material, or the like, a problem arises in visibility due to the influence of internal reflection of incident light at the interface. This problem is considered to be caused by the fact that the refractive index of the optical film is lower than that of the adhesive layer, and thus it is considered to solve the above problem by using an adhesive layer having a low refractive index. For example, as a method for forming an adhesive layer having a low refractive index by using an acrylic adhesive, it is considered to use a fluoroalkyl acrylate (refractive index of about 1.38) as a monomer unit in a general acrylic polymer (refractive index of usually 1.47 to 1.52) as a base polymer. However, the adhesive layer having a low refractive index using the base polymer containing the fluoroalkyl acrylate as a monomer unit has a high surface tension, and it is difficult to secure adhesion. It can be seen that it is extremely difficult to produce an adhesive layer having a low refractive index (for example, a refractive index of 1.40 or less) while ensuring the adhesiveness of the adhesive layer.

On the other hand, although the adhesive layer formed of the light diffusing adhesive composition of patent document 1 has a light diffusing function, it is difficult to sufficiently secure adhesion to an optical film or the like because light diffusing fine particles are dispersed throughout the entire range of the adhesive layer.

The purpose of the present invention is to provide an adhesive layer that, even when applied to an optical member having a low refractive index, such as an antireflection film, a light diffusion film, a lens film, a fresnel lens, a lenticular lens, or a microlens film, can effectively suppress internal reflection and has good adhesion, and a method for producing the same.

The present invention also provides an adhesive sheet having the adhesive layer, an optical film with an adhesive layer having the adhesive layer, and an image display device having the adhesive layer or the optical film with an adhesive layer.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found an adhesive layer or the like shown below, and have completed the present invention.

That is, the present invention relates to an adhesive layer having a first face and a second face, the second face being on the opposite side of the first face, characterized in that,

In the adhesive layer, a substrate of the entire adhesive layer is formed from an adhesive composition containing a base polymer,

the first face has a first refractive index based on the adhesive composition and the second face has a second refractive index lower than the first refractive index of the first face.

In the adhesive layer, a difference between the first refractive index of the first surface and the second refractive index of the second surface is preferably 0.02 to 0.45.

In the adhesive layer, the second refractive index of the second surface is preferably 1.45 or less.

As the adhesive layer, a low refractive index material having a refractive index lower than that of the base polymer may be dispersed on the second surface side.

In the pressure-sensitive adhesive layer, the thickness of the region in which the low refractive index material is dispersed is preferably 600nm or less in the thickness direction from the second surface side of the pressure-sensitive adhesive layer.

In the adhesive layer, the refractive index of the base polymer is preferably 1.40 to 1.55, and the refractive index of the low refractive index material is preferably 1.10 to 1.45. In addition, the difference between the refractive index of the base polymer and the refractive index of the low refractive index material is preferably 0.07 to 0.45.

As the low refractive index material, there may be mentioned: particles having an average particle diameter of 10nm to 150 nm.

As the low refractive index material, there may be mentioned: at least one particle selected from the group consisting of inorganic particles, porous silica particles, hollow silica nanoparticles, and hollow polymer particles, the inorganic particles being selected from the group consisting of MgF ₂ 、CaF ₂ And Na (Na) ₃ AlF ₆ At least one of the group consisting of.

The total light transmittance of the adhesive layer is preferably 85% or more.

The reflectivity of the second face of the adhesive layer is preferably 0.5% to 3.5%.

The difference between the reflectance of the first surface and the reflectance of the second surface of the adhesive layer is preferably 0.1% to 3.5%.

The gel fraction of the adhesive layer is preferably 30 to 95% by weight.

The storage modulus G' of the adhesive layer at 25 ℃ is preferably 0.05MPa to 0.50MPa.

The adhesive layer preferably has a tan delta peak value of-5 ℃ to-50 ℃ when measured in dynamic viscoelasticity at 1 Hz.

The present invention also relates to a method for producing an adhesive layer, comprising the steps of:

a step (1) in which a base adhesive layer is formed on a support using an adhesive composition containing a base polymer;

A step (2) in which a dispersion liquid in which a low refractive index material having a refractive index lower than that of the base polymer is dispersed is prepared;

a step (3) of applying the dispersion liquid to a second surface of the base adhesive layer on the opposite side of the first surface of the base adhesive layer from the second surface of the base adhesive layer, and allowing the low refractive index material contained in the dispersion liquid to penetrate in the thickness direction; and

and (4) drying the adhesive layer impregnated with the low refractive index material.

The present invention also relates to an adhesive sheet comprising the adhesive layer and a support on one or both sides of the adhesive layer.

The present invention also relates to an optical film with an adhesive layer, comprising an optical film and an adhesive layer provided on one or both sides of the optical film, characterized in that,

the adhesive layer of one or both sides is the aforementioned adhesive layer, and the first side of the adhesive layer is provided on the optical film.

In the optical film with an adhesive layer, a polarizing film is preferably used as the optical film.

The present invention also relates to an optical laminate comprising the adhesive layer-attached optical film and a low refractive index optical member attached to the adhesive layer of the adhesive layer-attached optical film.

The present invention also relates to an image display device comprising the adhesive layer, the adhesive layer-attached optical film, or the optical laminate.

Effects of the invention

The adhesive layer of the present invention has a refractive index different from that of a dispersion type adhesive layer in which fine particles are uniformly dispersed in the adhesive layer on both sides of a layer of the adhesive layer having a first side and a second side, and has a first refractive index based on an adhesive composition forming a base of the entire adhesive layer on one side of the first side and a second refractive index lower than the first refractive index of the first side on the other side of the second side. As described above, the adhesive layer of the present invention has an adhesive surface controlled to have a refractive index lower than that of the adhesive layer, and thus can adjust a refractive index difference with an optical member (for example, an antireflection film, a light diffusion film, a light guide film, a prism film, a lens film, a fresnel lens, a lenticular lens, a microlens film, or the like) formed of a material having a low refractive index, whereby reflection at an interface between the adhesive layer and the optical member can be suppressed, and can contribute to improvement of light extraction efficiency. When the second surface of the adhesive layer of the present invention is applied to a surface concave-convex shape portion of a microlens or the like, the surface concave-convex shape portion can be protected by filling the surface concave-convex shape portion with the adhesive layer, and as compared with the case where a void layer is provided in the surface concave-convex shape portion, the void can be filled without impairing the light extraction efficiency, and scratches and breakage of the shape due to vibration or the like at the time of handling or conveyance can be suppressed. In addition, although the second surface of the adhesive layer of the present invention has a refractive index adjustment region adjusted to a low refractive index, the region of low refractive index can be formed with high total light transmittance and without increasing the haze value. In addition, the adhesive layer of the present invention has good adhesion to a general optical film (for example, a polarizing film) because the adhesive layer has the adhesive strength inherent to the adhesive layer on the first surface, and on the second surface of the adhesive layer controlled to have a low refractive index, the adhesive composition forms a base, so that the adhesive strength to the optical film made of a low refractive index material can be ensured.

Drawings

Fig. 1 is a cross-sectional view showing one embodiment of an adhesive layer of the present invention.

Fig. 2 is a plan view showing a state of the second face of the adhesive layer of the present invention.

Fig. 3 is a schematic view showing a process for producing the adhesive layer of the present invention.

Fig. 4 is a cross-sectional view showing one embodiment of the adhesive sheet of the present invention.

Fig. 5 is a cross-sectional view showing one embodiment of the optical film with an adhesive layer of the present invention.

Fig. 6 is a cross-sectional view showing one embodiment of the optical laminate of the present invention.

Description of the reference numerals

1 … … adhesive layer

1a … … substrate (substrate) for an adhesive layer overall

2 … … Low refractive index Material

f1 … … first side of adhesive layer

f2 … … second side of adhesive layer

Thickness of T … … refractive index Regulation region

S … … support

3a … … support

3b … … support

4 … … optical film

5 … … low refractive optical component

10 … … Dispersion

Detailed Description

Hereinafter, the adhesive layer and the like of the present invention will be described with reference to the drawings.

< adhesive layer >)

As shown in fig. 1, the adhesive layer 1 of the present invention has a first face f1 and a second face f2, the second face f2 being on the opposite side of the first face f 1. In addition, in the adhesive layer 1, a base (substrate) 1a of the entire adhesive layer 1 is formed from an adhesive composition containing a base polymer. The first surface f1 has a first refractive index n1, and the second refractive index n2 of the second surface f2 is designed to be lower than the first refractive index n 1. In fig. 1, a case where a low refractive index material 2 having a refractive index lower than that of the base polymer is dispersed (enriched) in the substrate 1a on the side of the second face f2 is illustrated.

The first refractive index n1 of the first surface f1 corresponds to the refractive index of the adhesive layer obtained from the adhesive composition forming the substrate 1a in the adhesive layer 1 of the present invention. Therefore, the first refractive index n1 is determined by the adhesive composition forming the substrate 1 a. Since the refractive index of the base polymer is substantially the same as the refractive index of the substrate 1a of the entire adhesive layer 1, the first refractive index n1 of the first surface f1 is substantially determined by the refractive index of the base polymer. The adhesive composition forming the adhesive layer is described later, and the refractive index of the adhesive layer formed of a representative acrylic adhesive, for example, is generally about 1.47 to about 1.52. The refractive index of the adhesive layer formed of the polysiloxane-based adhesive is generally about 1.40.

On the other hand, the second refractive index n2 of the second surface f2 is not particularly limited as long as the relation between the second refractive index n2 and the first refractive index n1 of the first surface f1 satisfies n1 > n2, and may be appropriately determined in consideration of the refractive index or the like of the optical film having a low refractive index as an adherend. However, it is also considered that when the difference (n 1-n 2) between the first refractive index n1 and the second refractive index n2 is too large, internal reflection occurs in the adhesive layer 1, and therefore it is preferable to adjust the difference (n 1-n 2) to 0.02 to 0.45. The difference (n 1-n 2) is more preferably 0.03 to 0.35, still more preferably 0.03 to 0.25.

The second refractive index n2 of the second surface f2 is, for example, preferably 1.45 or less, more preferably 1.4 or less, still more preferably 1.35 or less, and still more preferably 1.3 or less, from the viewpoint of being able to effectively suppress internal reflection. If the second refractive index n2 is 1.4 or less, the second surface side of the adhesive layer 1 of the present invention may be used as an alternative use of the air layer. On the other hand, from the viewpoint of maintaining the adhesive strength, the second refractive index n2 is preferably 1.25 or more, and more preferably 1.28 or more. The second refractive index n2 is in a range lower than the lower limit value of the refractive index (generally about 1.47 to about 1.52) of the adhesive layer formed of the representative acrylic adhesive.

In the adhesive layer 1, as shown in fig. 1, when the low refractive index material 2 is dispersed on the second surface f2 side, the refractive index of the base polymer in the adhesive composition forming the base 1a is 1.40 to 1.55, and the refractive index of the low refractive index material 2 dispersed on the second surface f2 side in the base 1a is preferably 1.10 to 1.45. The difference between the refractive index of the base polymer and the refractive index of the low refractive index material 2 is preferably 0.07 to 0.45. The refractive index of the base polymer is more preferably 1.40 to 1.52, and still more preferably 1.40 to 1.50. The refractive index of the low refractive index material 2 is more preferably 1.14 to 1.42, and still more preferably 1.18 to 1.40. The difference between the refractive index of the base polymer and the refractive index of the low refractive index material 2 is more preferably 0.07 to 0.35, still more preferably 0.10 to 0.30. When the refractive index of the low refractive index material 2 is low, the refractive index can be reduced by a low amount, but on the other hand, the difference between the refractive index of the base polymer (adhesive layer 1 a) and the refractive index of the low refractive index material 2 becomes large, and scattering (haze) tends to occur easily, so that the refractive index difference is preferably adjusted to be not excessively large. In the case of a material made as a single layer film, the refractive index can be expressed in the form of a refractive index value of D-line measured by ellipsometry in an environment of 23 ℃.

As the low refractive index material 2, particles having an average particle diameter of 10nm to 150nm can be used. The particles having the average particle diameter in the aforementioned range are preferable from the viewpoint of suppressing the haze of the adhesive layer 1 to be low even in the case of being dispersed in the second surface f2 side of the adhesive layer 1 and maintaining high total light transmittance. The average particle diameter is preferably 20nm to 100nm, more preferably 20nm to 90nm. The average particle diameter of the particles is a value measured by a particle size distribution measuring apparatus based on a dynamic light scattering method.

Examples of the low refractive index material 2 include: mgF (MgF) ₂ (refractive index 1.38), caF ₂ (refractive index 1.43: fluorite), na ₃ AlF ₆ (refractive index 1.34: sodium hexafluoroaluminate (cryolite)), and the like. These materials (e.g., particles) may be used singly or in combination of two or more.

As the low refractive index material 2, for example, hollow particles may be used. The hollow particles may be any of inorganic particles and polymer particles. The hollow particles have void spaces with a low refractive index within the particles, and therefore the refractive index of the hollow particles is lower than the refractive index of the component forming the hollow particles. For example, silica has a refractive index of 1.46, and hollow silica nanoparticles (refractive index 1.24, trade name: THRULYA 5320, particle size 75nm, manufactured by Nitro catalyst Co., ltd.) and porous silica particles can be used as the low refractive index material. Further, hollow polymer fine particles (refractive index 1.32, trade name: TECHPOLYMER-NH model XX-255AA, particle diameter 80nm, hollow index 39%, manufactured by water-logging Co., ltd.) may be exemplified. In the case where the hollow particles are provided in the surface-treated layer having low refractive index, the hollow particles are hollow materials, and therefore, there is a problem in strength and scratch resistance, but the hollow particles (low refractive index material 2) in the present invention are in a form of being added (impregnated) in the adhesive layer 1, and therefore, can be applied without considering the problem of strength and scratch resistance.

As the low refractive index material 2, a fluoroalkyl group-containing oligomer, a polysiloxane resin oligomer, or the like can be used.

The thickness of the pressure-sensitive adhesive layer 1 is not particularly limited, but is usually 5 μm to 500. Mu.m, preferably 10 μm to 400. Mu.m, and more preferably 10 μm to 350. Mu.m. In fig. 1, the region in which the low refractive index material 2 is dispersed in the adhesive layer 1 is represented by a thickness T from the second surface f2 side. The thickness T is appropriately designed according to the thickness of the adhesive layer, and is generally preferably 600nm or less, more preferably 300nm or less, and still more preferably 200nm or less. In order to effectively suppress internal reflection when applied to an optical film having a low refractive index, the thickness T is preferably 10nm or more, more preferably 15nm or more, and even more preferably 20nm or more.

Although the region of the adhesive layer 1 in which the low refractive index material 2 is dispersed is irregularly uneven in relation to the thickness T in the relation to the substrate (matrix) 1a, in the present invention, the thickness T is determined by averaging measured values of the depth of the uneven.

The low refractive index material 2 is distributed in the second face f2 side in a state of being dispersed individually or in a state of being partially aggregated. As described with reference to fig. 1, the boundary between the region where the low refractive index material 2 is dispersed and the substrate 1a where the low refractive index material 2 is not dispersed is irregularly uneven, and when the thickness T is measured, a range in which 90% of the depth of the low refractive index material 2 is present at each measurement position is taken as a measurement value of the thickness T at the measurement position, and the measurement values at a plurality of measurement positions are averaged.

Fig. 2 is a plan view showing a state of the second face f2 of the adhesive layer 1. As shown in fig. 2, the low refractive index material 2 has an island structure in which the low refractive index material 2 is dispersed in the substrate 1a in an island shape, and a portion of the substrate 1a and a portion of the low refractive index material 2 are present. The area ratio of the low refractive index material 2 in the second face f2 is preferably in the range of 30% to 99%. The area ratio is a ratio of the area occupied by the low refractive index material 2 in a square region having one side of 10 μm to 200 μm to the total area of the square region, and the area ratio is determined by measuring a plurality of square regions and averaging the measured values.

The ratio of the low refractive index material 2 in the adhesive layer 1 is not particularly limited as long as the first refractive index n1 of the first surface f1 and the second refractive index n2 of the second surface f2 satisfy the relationship of n1 > n 2.

The total light transmittance of the entire adhesive layer 1 of the present invention is preferably 85% or more, more preferably 88% or more, and still more preferably 90% or more. The higher the total light transmittance of the adhesive layer 1, the more preferable. The haze value is preferably 1.5% or less, more preferably 1% or less, and still more preferably 0.8% or less. The lower the haze value of the adhesive layer 1 is, the more preferable. The total light transmittance and haze value of the entire adhesive layer 1 were measured in accordance with JIS K7361.

The reflectance of the second surface of the pressure-sensitive adhesive layer 1 of the present invention is preferably 0.5% to 3.5%. The second surface of the pressure-sensitive adhesive layer 1 of the present invention has a lower reflectance than the first surface, and the second surface has a reflectance that can control the internal surface reflection to be small in terms of the relationship with the low refractive index material is preferably 0.5% to 3.0%, and more preferably 0.5% to 2.5%. In the pressure-sensitive adhesive layer 1 of the present invention, the difference between the reflectance of the first surface and the reflectance of the second surface is preferably 0.1% to 3.5%.

In the pressure-sensitive adhesive layer 1 of the present invention, the second refractive index n2 of the second surface f2 is designed to be lower than the first refractive index n1, but the pressure-sensitive adhesive layer 1 of the present invention can be defined in relation to refractive indices of both surfaces, and can be regarded as an invention characterized in that the reflectance of the second surface f2 is lower than the reflectance of the first surface f 1.

The gel fraction of the adhesive layer 1 of the present invention is preferably 30 to 95% by weight. The gel fraction is preferably 30 to 90 wt%, more preferably 35 to 90 wt%, and even more preferably 40 to 90 wt%. When the gel fraction of the pressure-sensitive adhesive layer 1 is within the above range, it is preferable in terms of having stress relaxation property and ensuring follow-up property to irregularities. The gel fraction is related to the substrate 1a in the adhesive layer 1, excluding the low refractive index material 2.

< determination of gel fraction of adhesive layer >

About 0.2g was scraped from the adhesive layer (before penetration of the low refractive index material) as sample 1. The sample 1 was wrapped in a Teflon (registered trademark) film (trade name "NTF1122", manufactured by niton corporation) having a diameter of 0.2 μm, and then fastened with a kite string, to obtain a sample 2. The weight of sample 2 before the test described below was measured and used as the weight A. The weight a is the total weight of sample 1 (adhesive layer), teflon (registered trademark) film, and kite string. In addition, the total weight of the Teflon (registered trademark) film and kite string was taken as weight B. Next, the sample 2 was placed in a 50ml container filled with ethyl acetate, and left standing at 23 ℃ for 1 week. Then, sample 2 was taken out of the container, dried in a dryer at 130 ℃ for 2 hours to remove ethyl acetate, and then the weight of sample 2 was measured. The weight of sample 2 after the test was measured and used as the weight C. Then, the gel fraction (wt%) was calculated from the following formula.

Gel fraction (wt%) = (C-B)/(a-B) ×100

The storage modulus G' at 25℃of the pressure-sensitive adhesive layer 1 of the present invention is preferably 0.05MPa to 0.50MPa. The storage modulus G' is preferably 0.06MPa to 0.45MPa, more preferably 0.07MPa to 0.40MPa, still more preferably 0.08MPa to 0.35MPa. When the storage modulus G' of the adhesive layer 1 is within the above range, it is preferable to protect the image display device (LCD, OLED terminal, etc.) which is thinned and to secure dimensional stability at the time of dicing.

In addition, the adhesive layer 1 of the present invention preferably has a tan δ peak (glass transition temperature) of-5 ℃ to-50 ℃ at the time of dynamic viscoelasticity measurement at 1 Hz. The tan delta peak is preferably-7 ℃ to-50 ℃, more preferably-9 ℃ to-45 ℃, and even more preferably-10 ℃ to-40 ℃. When the tan δ peak value of the pressure-sensitive adhesive layer 1 is within the above range, it is a preferable mode in terms of securing drop impact resistance of an image display device (mobile terminal or the like).

< determination of storage modulus G' and tan delta peak of adhesive layer >)

A plurality of adhesive layers were laminated to prepare a test specimen having a thickness of about 2 mm. The test specimen was punched into a disk shape having a diameter of 7.9mm, sandwiched between parallel plates, and dynamic viscoelasticity was measured under the following conditions using an Advanced Rheology Expansion System (ARES) manufactured by Rheometric Scientific, whereby the storage modulus G' and tan delta peak of the adhesive layer at 25℃were read from the measurement results.

(measurement conditions)

Frequency: 1Hz

Deformation mode: torsion

Measuring temperature: -70-150 DEG C

Heating rate: 5 ℃/min

Next, a method for producing the adhesive layer of the present invention will be described with reference to fig. 3.

First, as step (1), a base adhesive layer 1' is formed on a support S using an adhesive composition containing a base polymer. The base adhesive layer 1' forms the substrate 1a in the resulting adhesive layer 1. The support 1 side in the base adhesive layer 1' is a first face f1' and the opposite side is a second face f2'. The method for forming the base adhesive layer 1' is not particularly limited, and may be formed by a method generally used in the art. Specifically, the adhesive composition may be formed by applying the adhesive composition to one surface of the support S and drying a coating film formed of the adhesive composition, or by irradiating active energy rays such as ultraviolet rays.

The support S is not particularly limited, and various substrates such as a release film and a transparent resin film substrate can be used.

Examples of the constituent material of the release film include: resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; porous materials such as paper, cloth, and nonwoven fabric; suitable sheet-like materials such as a web, a foam sheet, a metal foil, and a laminate thereof are preferably used in view of excellent surface smoothness. The release film may be subjected to release and anti-fouling treatment and antistatic treatment as needed.

On the other hand, as the step (2), a dispersion liquid 10 (not shown) in which a low refractive index material 2 having a refractive index lower than that of the base polymer used in the adhesive composition is dispersed is prepared. As the dispersion medium used in the dispersion liquid, a dispersion medium capable of dispersing the low refractive index material 2 and penetrating into the base adhesive layer 1' may be used, and may be appropriately selected according to the kind of the low refractive index material and the kind of the adhesive composition forming the base adhesive layer. The concentration of the low refractive index material in the dispersion medium is preferably adjusted to, for example, 0.1 to 10% by weight.

Examples of the dispersion medium include: alcohols such as methanol, ethanol, isopropanol, 1-propanol, n-butanol, 2-butanol, cyclohexanol, t-butanol, glycerin, ethylene glycol, 2-methyl-2, 4-pentanediol, phenol, and p-chlorophenol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 2-hexanone, and 2-heptanone; ethers such as diethyl ether, tetrahydrofuran, dioxane, anisole, etc.; esters such as ethyl acetate, butyl acetate, and methyl lactate; aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-hexane and cyclohexane, amides such as dimethylformamide and dimethylacetamide; cellosolves such as methyl cellosolve, ethyl cellosolve and methyl cellosolve acetate. These dispersion media may be used singly or in combination of two or more. The above-mentioned dispersion medium is merely an example, and the dispersion medium usable in the present invention is not limited thereto.

Next, as step (3), the dispersion liquid 10 is applied to the second surface f2 'of the base adhesive layer 1', and the low refractive index material 2 contained in the dispersion liquid 10 is allowed to penetrate from the second surface f2 'of the base adhesive layer 1' in the thickness direction. Fig. 3 (3) -1 shows a state immediately after the dispersion 10 is coated on the base adhesive layer 1', and (3) -2 shows a state in which the low refractive index material 2 permeates into the base adhesive layer 1'. The second surface f2' side of the base adhesive layer 1' is swelled by the dispersion medium of the dispersion liquid 10, and in the process, the low refractive index material 2 in the dispersion liquid 10 permeates into the base adhesive layer 1 '.

Next, as step (4), the base adhesive layer 1' impregnated with the low refractive index material 2 is dried. The adhesive layer 1 shown in fig. 1 can be obtained by evaporating the dispersion medium of the dispersion liquid 10 penetrating into the base adhesive layer 1' in the drying step. This state is shown in fig. 3 (4). The conditions of the drying step are determined according to the type of the dispersion medium.

The region (thickness T) in which the low refractive index material 2 is dispersed in the adhesive layer 1 is determined by the relationship between the adhesive composition forming the base adhesive layer 1' and the dispersion medium of the dispersion liquid 10. The dispersion medium may be appropriately selected so that the penetration depth reaches the above-mentioned value. In addition, the coating amount of the dispersion may be appropriately set so that the desired thickness T is achieved.

Examples of the method for applying the dispersion liquid include roll coating, contact roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, doctor blade coating, air knife coating, curtain coating, die lip coating, and die coating. The thickness T may be controlled by a coating method of the dispersion, a concentration of the dispersion, a coating amount, and the like.

< adhesive composition >

An adhesive composition containing a base polymer forming the base (matrix) 1a of the adhesive layer 1 of the present invention will be described.

The adhesive composition preferably uses a transparent material having adhesiveness that can be used for optical applications. The adhesive composition may be suitably selected from, for example, acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, polyurethane adhesives, epoxy adhesives, and polyether adhesives. From the viewpoints of transparency, processability, durability, and the like, an acrylic adhesive is preferably used. A base polymer corresponding to the kind of the adhesive composition may be used. In the present invention, an acrylic adhesive containing a (meth) acrylic polymer as a base polymer is preferable.

The acrylic adhesive may, for example, comprise a partial polymer of a monomer component containing an alkyl (meth) acrylate and/or a (meth) acrylic polymer derived from the monomer component. The base polymer of the acrylic adhesive comprises a partial polymer of a monomer component containing an alkyl (meth) acrylate and/or a (meth) acrylic polymer obtained from the monomer component.

The alkyl (meth) acrylate may be a linear or branched alkyl (meth) acrylate having 1 to 24 carbon atoms, and among these, an alkyl (meth) acrylate having 1 to 9 carbon atoms is preferable, and an alkyl (meth) acrylate having 4 to 9 carbon atoms may be preferable. The branched alkyl ester having 4 to 9 carbon atoms of (meth) acrylic acid is preferable in that the balance of adhesive properties is easily obtained. Specific examples of the branched alkyl (meth) acrylate having 4 to 9 carbon atoms include: n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and the like, and these alkyl (meth) acrylates may be used singly or in combination of two or more.

In the present invention, the alkyl (meth) acrylate having an alkyl group having 1 to 24 carbon atoms at the ester end is preferably 40% by weight or more, more preferably 50% by weight or more, still more preferably 60% by weight or more, based on the total amount of the monofunctional monomer components forming the (meth) acrylic polymer.

The monomer component may contain a comonomer other than the alkyl (meth) acrylate as a monofunctional monomer component. The comonomer may be used as the rest of the monomer components other than the alkyl (meth) acrylate.

As the comonomer, for example, a cyclic nitrogen-containing monomer may be contained. As the cyclic nitrogen-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or vinyl group and having a cyclic nitrogen structure can be used without particular limitation. The cyclic nitrogen structure preferably has a nitrogen atom within the cyclic structure. Examples of the cyclic nitrogen-containing monomer include: lactam vinyl monomers such as N-vinyl pyrrolidone, N-vinyl-epsilon-caprolactam, methyl vinyl pyrrolidone, and the like; vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinylAnd vinyl monomers having nitrogen-containing heterocyclic rings such as oxazole and vinyl morpholine. In addition, there may be mentioned: a (meth) acrylic monomer containing a heterocyclic ring such as a morpholine ring, a piperidine ring, a pyrrolidine ring, or a piperazine ring. Specifically, it is possible to list: n-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like. Among the cyclic nitrogen-containing monomers, lactam-based vinyl monomers are preferred.

In the present invention, the cyclic nitrogen-containing monomer is preferably 0.5 to 50% by weight, more preferably 0.5 to 40% by weight, and even more preferably 0.5 to 30% by weight, relative to the total amount of the monofunctional monomer components forming the (meth) acrylic polymer.

The monomer component used in the present invention may contain a hydroxyl group-containing monomer as a monofunctional monomer component. As the hydroxyl group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or vinyl group and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing monomer include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and the like; hydroxyalkyl cycloalkane (meth) acrylates such as (4-hydroxymethyl cyclohexyl) methyl (meth) acrylate. Furthermore, there may be mentioned: hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like. These hydroxyl group-containing monomers may be used alone or in combination. Among them, hydroxyalkyl (meth) acrylates are preferable.

In the present invention, the hydroxyl group-containing monomer is preferably 1% by weight or more, more preferably 2% by weight or more, and still more preferably 3% by weight or more, based on the total amount of the monofunctional monomer components forming the (meth) acrylic polymer, in terms of improving the adhesive strength and cohesive force. On the other hand, when the hydroxyl group-containing monomer is too much, the pressure-sensitive adhesive layer may be hardened and the tackiness may be reduced, and the viscosity of the pressure-sensitive adhesive composition may be too high or gelation may occur, so that the hydroxyl group-containing monomer is preferably 30% by weight or less, more preferably 27% by weight or less, and still more preferably 25% by weight or less, relative to the total amount of the monofunctional monomer components forming the (meth) acrylic polymer.

The monomer component forming the (meth) acrylic polymer may contain other functional group-containing monomers as monofunctional monomers, and examples thereof include carboxyl group-containing monomers and monomers having a cyclic ether group.

As the carboxyl group-containing monomer, a monomer having a carboxyl group and having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include: the carboxyl group-containing monomers may be used alone or in combination, such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. For itaconic acid, maleic acid, their anhydrides may be used. Among them, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable. The carboxyl group-containing monomer may be optionally used as the monomer component used in the production of the (meth) acrylic polymer of the present invention, but may not be used.

As the monomer having a cyclic ether group, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a cyclic ether group such as an epoxy group or an oxetanyl group can be used without particular limitation. Examples of the epoxy group-containing monomer include: glycidyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl glycidyl (meth) acrylate, and the like. Examples of oxetanyl group-containing monomers include: 3-oxetanyl methyl (meth) acrylate, 3-methyl-3-oxetanyl methyl (meth) acrylate, 3-ethyl-3-oxetanyl methyl (meth) acrylate, 3-butyl-3-oxetanyl methyl (meth) acrylate, 3-hexyl-3-oxetanyl methyl (meth) acrylate, and the like. These monomers having a cyclic ether group may be used alone or in combination.

In the present invention, the carboxyl group-containing monomer and the monomer having a cyclic ether group are preferably 30% by weight or less, more preferably 27% by weight or less, and still more preferably 25% by weight or less, based on the total amount of the monofunctional monomer components forming the (meth) acrylic polymer.

In the monomer component forming the (meth) acrylic polymer of the present invention, examples of the comonomer include a monomer derived from CH ₂ ＝C(R ¹ )COOR ² (R is as described above) ¹ Represents hydrogen or methyl, R ² Alkyl (meth) acrylate represented by a substituted alkyl group having 1 to 3 carbon atoms and a cyclic cycloalkyl group).

Here, R is as R ² Is substituted carbon atom of (C)The substituent of the alkyl group having 1 to 3 is preferably an aryl group having 3 to 8 carbon atoms or an aryloxy group having 3 to 8 carbon atoms. The aryl group is not limited, and phenyl is preferable.

As such a group consisting of CH ₂ ＝C(R ¹ )COOR ² Examples of the monomer represented may be: phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, 3, 5-trimethylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and the like. These monomers may be used alone or in combination.

In the present invention, the above-mentioned monomer represented by CH is used in relation to the total amount of monofunctional monomer components forming the (meth) acrylic polymer ₂ ＝C(R ¹ )COOR ² The (meth) acrylate represented may be used in an amount of 50% by weight or less, preferably 45% by weight or less, more preferably 40% by weight or less, and still more preferably 35% by weight or less.

As other comonomers, it is also possible to use vinyl acetate, vinyl propionate, styrene, alpha-methylstyrene; glycol acrylate monomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate; acrylic monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine-containing (meth) acrylate, polysiloxane (meth) acrylate, and 2-methoxyethyl acrylate; amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, N-acryloylmorpholine, vinyl ether monomers, and the like. Further, as the comonomer, a monomer having a cyclic structure such as terpene (meth) acrylate or tetrahydrodicyclopentadiene (meth) acrylate can be used.

Further, a silane monomer containing a silicon atom and the like can be exemplified. Examples of the silane monomer include: 3-acryloxypropyl triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyl trimethoxysilane, 4-vinylbutyl triethoxysilane, 8-vinyloctyl trimethoxysilane, 8-vinyloctyl triethoxysilane, 10-methacryloxydecyl trimethoxysilane, 10-acryloxydecyl trimethoxysilane, 10-methacryloxydecyl triethoxysilane, 10-acryloxydecyl triethoxysilane, and the like.

In addition to the monofunctional monomers exemplified above, the monomer component forming the (meth) acrylic polymer of the present invention may contain a polyfunctional monomer as needed in order to adjust the cohesive force of the adhesive composition.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, and examples thereof include: ester compounds of a polyhydric alcohol such as (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 2-ethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and tetramethylolmethane tri (meth) acrylate with (meth) acrylic acid; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, and the like. Among them, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate can be preferably used. The polyfunctional monomer may be used singly or in combination of two or more.

The amount of the polyfunctional monomer to be used varies depending on the molecular weight, the number of functional groups, and the like, and is preferably 3 parts by weight or less, more preferably 2 parts by weight or less, and still more preferably 1 part by weight or less, based on 100 parts by weight of the total of the monofunctional monomers. The lower limit is not particularly limited, but is preferably 0 parts by weight or more, more preferably 0.001 parts by weight or more. The adhesive strength can be improved by using the polyfunctional monomer in an amount within the above range.

The production of the (meth) acrylic polymer may be carried out by appropriately selecting known production methods such as solution polymerization, radiation polymerization such as Ultraviolet (UV) polymerization, bulk polymerization, and various radical polymerization such as emulsion polymerization. The obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

In the present invention, a partial polymer of the monomer component may be suitably used.

In the case of producing the (meth) acrylic polymer by radical polymerization, a polymerization initiator, a chain transfer agent, an emulsifier, etc. which can be used for radical polymerization may be appropriately added to the monomer component and polymerized. The polymerization initiator, chain transfer agent, emulsifier, etc. that can be used for radical polymerization are not particularly limited, and may be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent, and the reaction conditions, and the amount of the polymerization initiator and the chain transfer agent can be appropriately adjusted according to the kind of the polymerization initiator and the chain transfer agent.

For example, in the case of solution polymerization, ethyl acetate, toluene, or the like can be used as the polymerization solvent. As a specific example of solution polymerization, the reaction is carried out under the following reaction conditions: the polymerization initiator is added under an inert gas flow such as nitrogen, typically at about 50 to about 70 c for about 5 to about 30 hours.

In the case where the (meth) acrylic polymer is produced by radiation polymerization, the (meth) acrylic polymer can be produced by polymerizing the monomer component by irradiation with radiation such as electron beam or Ultraviolet (UV) radiation. In the ultraviolet polymerization, it is preferable to include a photopolymerization initiator in the monomer component because of the advantage of shortening the polymerization time.

(silane coupling agent)

In addition, a silane coupling agent may be contained in the adhesive composition of the present invention. The amount of the silane coupling agent to be blended is preferably 1 part by weight or less, more preferably 0.01 to 1 part by weight, and still more preferably 0.02 to 0.6 part by weight, based on 100 parts by weight of the base polymer (for example, the (meth) acrylic polymer).

(crosslinking agent)

The adhesive composition of the present invention may contain a crosslinking agent. The crosslinking agent comprises an isocyanate crosslinking agent, an epoxy crosslinking agent, a polysiloxane crosslinking agent, Oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, peroxide-based crosslinking agents, and the like. The crosslinking agent may be used singly or in combination of two or more. Among them, an isocyanate-based crosslinking agent is preferably used.

The content of the entire crosslinking agent is preferably 5 parts by weight or less, more preferably 0.01 to 5 parts by weight, still more preferably 0.01 to 4 parts by weight, and particularly preferably 0.02 to 3 parts by weight, based on 100 parts by weight of the monofunctional monomer component forming the (meth) acrylic polymer.

(other additives)

In the adhesive composition of the present invention, in addition to the aforementioned components, an appropriate additive may be contained according to the purpose. For example, it is possible to list: viscosity modifiers, peeling modifiers, tackifiers (for example, tackifiers which are solid, semisolid, or liquid at ordinary temperature including rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenol resins, and the like), plasticizers, softeners, pigments, colorants (pigments, dyes, and the like), pH modifiers (acids or bases), rust inhibitors, antioxidants, light stabilizers, ultraviolet absorbers, and the like.

The adhesive sheet of the present invention has the adhesive layer 1 and has a support on one side or both sides of the adhesive layer 1. Fig. 4 shows a case where the support 3a is provided on the first surface f1 of the adhesive layer 1 and the support 3b is provided on the second surface f 2. The same support as the support S used in the adhesive layer 1 shown in fig. 3 can be used for the supports 3a, 3 b. In addition, the support 3a may be used as it is as the support S used in the method of manufacturing the adhesive layer 1 shown in fig. 3. The support 3b may be appropriately disposed on the second face f2 of the adhesive layer 1 after the adhesive layer 1 is manufactured using the manufacturing method shown in fig. 3.

The adhesive layer-attached optical film a of the present invention has an optical film 4 and an adhesive layer 1 provided on one side or both sides of the optical film 4. The adhesive layer 1 is provided on one side or both sides of the optical film 4. The adhesive layer 1 is provided on the optical film 4 on the first surface f1 side of the adhesive layer 1. In the case where the adhesive layer 1 is provided on one side of the optical film 4, a normal adhesive layer may be provided on the other side. Fig. 5 shows a case where the adhesive layer 1 is provided only on one side of the optical film 4. Fig. 5 shows a case where the support 3b is provided on the second surface f2 of the adhesive layer 1.

< optical film >)

As the optical film, for example, an optical film used for forming an image display device such as a liquid crystal display device can be used, and the kind thereof is not particularly limited. For example, as the optical film, a polarizing film can be cited. As the polarizing film, a polarizing film having a transparent protective film on one side or both sides of a polarizer is generally used.

< polarizing film >

As the polarizing film, a polarizing film having a transparent protective film on at least one surface of a polarizer can be exemplified.

The polarizer is not particularly limited, and various polarizers may be used. Examples of the polarizer include: a polarizer obtained by uniaxially stretching a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film after adsorbing a dichroic substance such as iodine or a dichroic dye, a polyolefin oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride, and the like. Among them, a polarizer containing a polyvinyl alcohol film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, and is usually about 5 μm to about 80 μm.

A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching the film can be produced, for example, by immersing the polyvinyl alcohol film in an aqueous solution of iodine, dyeing the film, and stretching the film to 3 to 7 times the original length. The aqueous solution may be immersed in an aqueous solution of potassium iodide or the like which may contain boric acid, zinc sulfate, zinc chloride or the like as required. If necessary, the polyvinyl alcohol film may be immersed in water before dyeing and washed with water. The polyvinyl alcohol film is washed with water to remove stains and an anti-blocking agent on the surface of the polyvinyl alcohol film, and in addition, the polyvinyl alcohol film is swelled to prevent uneven dyeing and the like. The stretching may be performed after dyeing with iodine, or may be performed simultaneously with dyeing, or may be performed after dyeing with iodine. Stretching may be performed in an aqueous solution of boric acid, potassium iodide, or the like, or in a water bath.

In the present invention, a thin polarizer having a thickness of 10 μm or less may be used. From the viewpoint of thickness reduction, the thickness is preferably 1 μm to 7 μm. Such a thin polarizer is preferable in terms of having less thickness unevenness, excellent visibility, and less dimensional change, and thus, excellent durability, and also in terms of realizing a thin polarizing film having a thickness.

As the thin polarizer, there can be typically mentioned: a thin polarizing film described in japanese patent application laid-open publication No. 51-069644, japanese patent application laid-open publication No. 2000-338329, single-file book of international publication No. 2010/100917, or japanese patent application laid-open publication No. 4751481, japanese patent application laid-open publication No. 2012-073563. These thin polarizing films can be obtained by a production method including a step of stretching a layer of a polyvinyl alcohol resin (hereinafter also referred to as PVA-based resin) and a stretching resin base material in a laminate state and a step of dyeing. With this production method, even if the PVA-based resin layer is thin, it is possible to carry out stretching without causing defects such as breakage due to stretching by being supported by the stretching resin base material.

In the case of the thin polarizing film, in order to improve polarization performance by stretching at a high magnification in a production method including a step of stretching in a laminate and a step of dyeing, a thin polarizing film obtained by a production method including a step of stretching in an aqueous boric acid solution as described in the specification of japanese patent application laid-open No. 2010/100917, or in the specification of japanese patent application laid-open No. 4751481, and in japanese patent application laid-open No. 2012-073563 is preferable, and a thin polarizing film obtained by a production method including a step of stretching in air with assistance before stretching in an aqueous boric acid solution as described in the specification of japanese patent application laid-open No. 4751481 and japanese patent application laid-open No. 2012-073563 is particularly preferable.

As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like can be used. Specific examples of such thermoplastic resins include: cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. A transparent protective film is laminated on one side of the polarizer through an adhesive layer, and a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, polysiloxane, or the like or an ultraviolet curable resin may be used as the transparent protective film on the other side. One or more kinds of any suitable additives may be contained in the transparent protective film. Examples of the additive include: ultraviolet light absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-colorants, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the transparent protective film is 50 wt% or less, there is a possibility that the thermoplastic resin may not sufficiently exhibit high transparency or the like inherent in the thermoplastic resin.

The thickness of the transparent protective film can be appropriately determined, and is generally about 1 μm to about 500 μm in view of workability such as strength and handleability, film property, and the like.

A functional layer such as a hard coat layer, an antireflection layer, and an anti-sticking layer may be formed on the surface of the transparent protective film, which is not adhered to the polarizer, and a treatment for diffusion or anti-glare may be performed.

The adhesive used for bonding the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and various types of adhesives such as aqueous, solvent-based, hot-melt-based, radical-curable, and cationic-curable adhesives can be used, and aqueous adhesives or radical-curable adhesives are preferable.

Examples of the optical film include: as an optical film for forming an optical layer of a liquid crystal display device or the like, a reflective plate, a semi-reflective and semi-transmissive plate, a phase difference film (including a 1/2 or 1/4 wave plate), a visual compensation film, a brightness enhancement film, or the like may be used. These may be used alone as an optical film, or may be laminated on the polarizing film at the time of actual use to use one layer or two or more layers. As the transparent protective film, a retardation film may be used. The retardation film may be a film obtained by stretching or shrinking a polymer film or a film obtained by aligning or immobilizing a liquid crystal material, as appropriate for the purpose.

The optical film in which the optical layers are laminated on the polarizing film may be formed by laminating the optical layers one on another in the course of manufacturing a liquid crystal display device or the like, but the optical film formed by laminating the optical layers in advance has the advantage of being excellent in quality stability, assembly work or the like, and thus improving the manufacturing process of the liquid crystal display device or the like. An appropriate adhesive means such as an adhesive layer may be used for lamination. In the case of adhesion of the polarizing film to other optical layers, the optical axes thereof may be set to an appropriate arrangement angle according to the target phase difference characteristics and the like.

The optical laminate B of the present invention comprises an optical film A with an adhesive layer and an optical member 5 with a low refractive index bonded to the adhesive layer 1 of the optical film A with an adhesive layer. The optical member 5 is provided on the second face f2 side of the adhesive layer 1. The optical laminate B shown in fig. 6 exemplifies a case in which the support 3B (for example, a release film) is peeled from the adhesive layer-attached optical film a shown in fig. 5, and then the optical member 5 is attached to the adhesive layer 1. Examples of the optical member 5 include an antireflection film, a light diffusion film, a prism film, a light guide film, a lens film, a fresnel lens, a lenticular lens, and a microlens film.

The optical film or optical laminate with an adhesive layer of the present invention can be preferably used for the formation of various image display devices such as liquid crystal display devices. The formation of the liquid crystal display device can be performed in a conventional manner. That is, the liquid crystal display device is generally formed by appropriately assembling a display panel such as a liquid crystal cell, an optical film or an optical laminate with an adhesive layer, and, if necessary, a component such as an illumination system, and incorporating a driving circuit or the like, and the present invention is not limited to this, and may be carried out in accordance with a conventional manner. As the liquid crystal cell, for example, any type of liquid crystal cell such as TN type, STN type, pi type, VA type, IPS type, or the like can be used.

A liquid crystal display device in which an optical film or an optical laminate with an adhesive layer is disposed on one side or both sides of a display panel such as a liquid crystal cell, a liquid crystal display device in which a backlight or a reflective plate is used in an illumination system, or the like can be suitably formed. In this case, the optical film or the optical laminate with an adhesive layer of the present invention may be provided on one side or both sides of a display panel such as a liquid crystal cell. In the case where the optical films are provided on both sides, these optical films may be the same or different. In forming the liquid crystal display device, for example, one or more of a diffusion layer, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion sheet, a backlight, and other appropriate members may be disposed at appropriate positions.

Examples (example)

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The parts and% in each example are based on weight. The room temperature conditions not specifically defined below were 23℃and 65% RH.

(mold release film)

A polyester film (trade name: diafoil MRF, mitsubishi resin Co., ltd.) having a thickness of 38 μm, which was subjected to a release treatment with polysiloxane on one side, was used.

Comparative example 1

(preparation of adhesive composition (A))

A monomer mixture was prepared by charging 41 parts by weight of 2-ethylhexyl acrylate (2 EHA), 41 parts by weight of isostearyl acrylate (ISTA), 14 parts by weight of N-vinyl-2-pyrrolidone (NVP), 4 parts by weight of 4-hydroxybutyl acrylate (4 HBA), 0.035 parts by weight of two photopolymerization initiators (trade name: irgacure 184, manufactured by BASF) and 0.035 parts by weight of a photopolymerization initiator (trade name: irgacure 651, manufactured by BASF) into a four-necked flask. Then, the monomer mixture was partially photopolymerized by exposure to ultraviolet rays under a nitrogen atmosphere, thereby obtaining a partial polymer (acrylic polymer syrup) having a polymerization rate of about 10% by weight. To 100 parts by weight of the acrylic polymer syrup thus obtained, 0.025 parts by weight of trimethylolpropane triacrylate (TMPTA) and 0.3 parts of a silane coupling agent (trade name: KBM-403, manufactured by Xinyue chemical Co., ltd.) were added, and then they were uniformly mixed to prepare an adhesive composition (A).

(production of adhesive layer (A))

The pressure-sensitive adhesive composition (A) was applied to the release treated surface of the release film so that the thickness of the pressure-sensitive adhesive layer was 100. Mu.m, thereby forming a coating layer. Next, another release film is coated on the surface of the coating layer with the release-treated surface as the coating layer side. Then, at illuminance: 6.5mW/cm ² Light amount: 2000mJ/cm ² Peak wavelength: ultraviolet irradiation was performed at 350nm to photocure the coating layer to form an adhesive layer (A), thereby producing an adhesive sheet (substrate-free type, adhesive layer) having release films on both sides of the adhesive layer (A)Is formed by the following steps: 100 μm). Refractive index (n) of D line of adhesive layer (A) measured in an Abbe refractometer at 23 DEG C _D ) 1.48, and the gel fraction of the adhesive layer (A) was 67%.

Comparative example 2

(preparation of adhesive composition (B))

A prepolymer composition (polymerization rate: 9%) was obtained by polymerizing a part of the above-mentioned monomer component by blending 0.050 parts by weight of 1-hydroxycyclohexyl phenyl ketone (trade name: irgacure 184, having an absorption band in the wavelength range of 200nm to 370nm, manufactured by BASF corporation) as a photopolymerization initiator, 0.050 parts by weight of 2, 2-dimethoxy-1, 2-diphenylethane-1-one (trade name: irgacure 651, having an absorption band in the wavelength range of 200nm to 380nm, manufactured by BASF corporation) with a monomer mixture composed of 76 parts by weight of 2-ethylhexyl acrylate (2 EHA), 18 parts by weight of N-vinyl-2-pyrrolidone (NVP) and 16 parts by weight of 2-hydroxyethyl acrylate (HEA), and then irradiating ultraviolet rays until the viscosity (measurement condition: BH viscometer No. 5 rotor, 10rpm, measurement temperature 30 ℃ C.) was about 20 Pa.s. Next, 0.060 parts by weight of hexanediol diacrylate (HDDA) and 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Xinyue chemical Co., ltd.) were added to the prepolymer composition and mixed, thereby obtaining an adhesive composition (b).

(preparation of adhesive composition (B))

To the adhesive composition (B) thus obtained (100 parts by weight of the monomer component forming the acrylic polymer), 0.8 part by weight (solid component weight) of 2, 4-bis- [ {4- (4-ethylhexyl oxy) -4-hydroxy } -phenyl ] -6- (4-methoxyphenyl) -1,3, 5-triazine (trade name: tinosorb S, absorption spectrum absorption maximum wavelength: 348 nm, manufactured by BASF Japanese Co., ltd.) and 0.3 part by weight of bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide (trade name: irgacure 819 having an absorption band in the range of 200nm to 450nm wavelength) dissolved in butyl acrylate were added and stirred, thereby obtaining an adhesive composition (B).

(production of adhesive layer (B))

The pressure-sensitive adhesive composition (B) was applied to the release treated surface of the release film so that the thickness of the pressure-sensitive adhesive layer was 150. Mu.m, thereby forming a coating layer. Next, another release film is coated on the surface of the coating layer with the release-treated surface as the coating layer side. Then, at illuminance: 6.5mW/cm ² Light amount: 2000mJ/cm ² Peak wavelength: the adhesive sheet (no base material type, thickness of adhesive layer: 150 μm) having release films provided on both sides of the adhesive layer (B) was produced by irradiating ultraviolet rays at 350nm and photocuring the coating layer to form the adhesive layer (B). Refractive index (n) of D line of adhesive layer (B) measured in an environment of 23℃by Abbe refractometer _D ) 1.49, and the gel fraction of the adhesive layer (B) was 88%.

Comparative example 3

(preparation of adhesive composition (C))

Into a detachable flask having a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction tube, 95 parts by weight of Butyl Acrylate (BA), 5 parts by weight of Acrylic Acid (AA), 0.2 parts by weight of azobisisobutyronitrile as a polymerization initiator, and 233 parts by weight of ethyl acetate were charged, and then nitrogen gas was circulated, and nitrogen gas substitution was performed for about 1 hour while stirring. Then, the flask was heated to 60℃and reacted for 7 hours, whereby an acrylic polymer having a weight average molecular weight (Mw) of 110 ten thousand was obtained. To the acrylic polymer solution (solid content: 100 parts by weight), 0.8 parts by weight of trimethylolpropane-toluene diisocyanate (trade name: coronate L, manufactured by Nippon polyurethane Co., ltd.) as an isocyanate-based crosslinking agent and 0.1 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Xinyue chemical Co., ltd.) were added, to prepare an adhesive composition (C: solution).

(production of adhesive layer (C))

The adhesive composition (C: solution) was applied to the release treated surface of the release film in such a manner that the thickness after drying was 23. Mu.m, and then dried at 100℃for 3 minutes to remove the solvent, thereby obtaining an adhesive layer (C) A. The invention relates to a method for producing a fibre-reinforced plastic composite Then, the crosslinking treatment was performed by heating at 50℃for 48 hours. Another release film was coated on the exposed surface of the obtained adhesive layer (C) so that the release treated surface was the exposed surface side of the adhesive layer (C), whereby an adhesive sheet (no base material type, thickness of the adhesive layer: 23 μm) having release films on both surfaces of the adhesive layer (C) was produced. Refractive index (n) of D line of adhesive layer (C) measured in an environment of 23℃by Abbe refractometer _D ) 1.47, and the gel fraction of the adhesive layer (C) was 82%.

Comparative example 4

(preparation of adhesive composition (D))

99 parts by weight of Butyl Acrylate (BA), 1 part by weight of 4-hydroxybutyl acrylate (4 HBA), 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator, and ethyl acetate as a polymerization solvent so that the solid content was 30% by weight were charged as monomer components in a detachable flask having a thermometer, a stirrer, a reflux condenser, and a nitrogen introducing tube, and then nitrogen gas was circulated, and nitrogen substitution was performed for about 1 hour while stirring. Then, the flask was heated to 60℃and reacted for 7 hours, thereby obtaining an acrylic polymer having a weight average molecular weight (Mw) of 110 ten thousand. To this acrylic polymer solution (solid content 100 parts), 0.11 parts of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui chemical Co., ltd., "Takenate D110N") as an isocyanate-based crosslinking agent and 0.1 parts of a silane coupling agent (manufactured by Xinyue chemical Co., ltd., "KBM-403") were added to prepare an adhesive composition (D: solution).

(production of adhesive layer (D))

The pressure-sensitive adhesive composition (D: solution) was applied to the release treated surface of the release film so that the thickness thereof after drying was 20. Mu.m, and the solvent was removed by drying at 120℃for 3 minutes, whereby a pressure-sensitive adhesive layer (D) was obtained. Then, the crosslinking treatment was performed by heating at 50℃for 48 hours. Another release film was coated on the exposed surface of the obtained adhesive layer (D) so that the release treated surface was the exposed surface side of the adhesive layer (D), thereby producing an adhesive having release films provided on both surfaces of the adhesive layer (D)Lamination (no substrate type, thickness of adhesive layer: 23 μm). Refractive index (n) of D line of adhesive layer (D) measured in an Abbe refractometer at 23 DEG C _D ) 1.47, and the gel fraction of the adhesive layer (D) was 75%.

Example 1

(preparation of a Dispersion containing Low refractive index particles)

As a dispersion liquid containing low refractive index particles, hollow silica nanoparticles (hollow particles having a refractive index of 1.24, an average primary particle diameter of 75nm, trade name: THRULYA 5320, manufactured by daily volatile catalyst chemical Co., ltd.) were diluted with a dispersion medium (methyl ethyl ketone/methyl isobutyl ketone=9/1:volume ratio), to prepare a dispersion liquid having a particle concentration of 1.5 wt%.

(production of refractive index-adjusted adhesive layer)

One release film of the adhesive sheet obtained in comparative example 1 was peeled off. The above dispersion was coated on the surface of the exposed adhesive layer (a) using a bar coater RDS No.3 in such a manner that the thickness of the refractive index adjusting region was about 20nm to about 150nm, and then dried in a drying oven at 110 ℃ for 180 seconds. Next, a second release film was laminated again on the surface of the adhesive layer (a) in which the hollow silica nanoparticles were dispersed, thereby obtaining an adhesive sheet. The release film on the opposite side of the second release film was used as the first release film.

Examples 2 to 8

An adhesive sheet having an adhesive layer with a refractive index adjusted was produced in the same manner as in example 1, except that the type of the adhesive layer and the type of the dispersion (type of the low refractive index particles, average particle diameter thereof, type of the dispersion medium, and particle concentration) in example 1 were changed as shown in table 1.

The bar coater RDS No.5 was used when the target thickness of the refractive index adjustment region after drying was about 150nm or more and about 300nm or less, and the bar coater RDS No.3 was used when the target thickness of the refractive index adjustment region after drying was about 20nm to about 150 nm.

(evaluation)

The results of the following evaluations of the adhesive layers (adhesive sheets) obtained in examples and comparative examples are shown in table 1.

< determination of average surface refractive index >

For the average surface refractive index of the adhesive layer (refractive index adjustment region side: second surface) obtained in the example, the refractive index at sodium D line (589 nm) was measured using an ellipsometer (EC-400, manufactured by JA. Woolam). The double-sided release films were peeled from the adhesive sheets obtained in examples and comparative examples, and the average refractive index of the surface (second surface) coated with the dispersion was measured in a state where the black sheet was bonded to the surface (first surface) not coated with the dispersion. In the pressure-sensitive adhesive sheet of comparative example, the two release films were peeled off, and the average refractive index of the surface of the pressure-sensitive adhesive layer was measured in a state where a black sheet was bonded to one surface. The refractive index of both sides of the adhesive layer of the adhesive sheet of the comparative example was the same.

< measurement of thickness of refractive index adjustment region >

A cross section of the adhesive layer in the depth direction was prepared and TEM observation was performed. The thickness of the refractive index adjustment region was measured from the obtained TEM image (direct magnification 3000 times to 30000 times). The thickness of the refractive index adjustment region is an average value of the projections and depressions of the interface between the region in which particles are dispersed and the region in which particles are not dispersed in the adhesive layer, and is a thickness of the depth of the region in which 90% (area) of particles are present when binarizing the surface TEM image by image processing software (ImageJ) in the case where it is difficult to distinguish the interface.

< total light transmittance, haze >)

The second release film (second side of the adhesive layer) was peeled off from the adhesive sheet obtained in the examples and attached to a glass slide (trade name: white polishing No.1, thickness: 0.8mm to 1.0mm, total light transmittance: 92%, haze: 0.2%, manufactured by Song Nitro Co., ltd.). The first release film on the other side was peeled off again, thereby producing a test piece having a layer structure of an adhesive layer (refractive index adjustment region is slide side)/slide. On the other hand, in the adhesive layer of the comparative example, the release film on one side was peeled off and bonded to the same slide glass, and the release film on the other side was peeled off, whereby a test piece having a layer structure of the adhesive layer/slide glass was produced. The total light transmittance and haze value of the test piece in the visible light range were measured by using a haze meter (device name: HM-150, manufactured by Toku Kogyo Co., ltd.).

< tackiness >)

From the adhesive sheets obtained in examples and comparative examples, small pieces having a length of 100mm and a width of 20mm were cut. Then, a first release film (side of the adhesive layer to which the dispersion was not applied) was peeled off from the pellet obtained from the adhesive sheet of example, and a PET film (trade name: lumiror S-10, thickness: 25 μm, manufactured by Toshi Co., ltd.) was adhered (lining) on the adhesive layer. Then, the second release film was peeled off and pressed against a glass plate (trade name: soda lime glass #0050, manufactured by Song Nitro Co., ltd.) as a test plate under a press condition of 2kg roller and 1 round trip, thereby producing a sample composed of the test plate/the adhesive layer (the first surface is the PET side)/the PET film. On the other hand, a sample was produced by peeling one release film from the pressure-sensitive adhesive sheet of comparative example, adhering the same PET film as described above to the pressure-sensitive adhesive layer, and peeling the other release film from the pressure-sensitive adhesive layer. The obtained sample was autoclaved (50 ℃ C., 0.5MPa, 15 minutes) and then naturally cooled for 30 minutes under an atmosphere of 50% R.H. at 23 ℃. After natural cooling, the adhesive sheet (adhesive layer/PET film) was peeled from the test sheet under conditions of a drawing speed of 300 mm/min and a peeling angle of 180℃in an atmosphere of 50% R.H. at 23℃according to JIS Z0237 using a tensile tester (apparatus name: autograph AG-IS, shimadzu corporation), and 180℃peeling adhesion (N/20 mm) was measured.

< measurement of surface reflectivity >

The side (second side) of the adhesive layer obtained in the example on which the dispersion was applied was used as the reflectance measurement surface. The first release film (side of the adhesive layer to which the dispersion was not applied) was peeled off from the adhesive sheet obtained in examples, and a black acrylic resin plate (trade name "CLAREX", manufactured by ridong resin industry co., ltd.) was attached thereto, and then the second release film (side of the adhesive layer to which the dispersion was applied) was peeled off, and the peeled off surface was used as a surface reflectance measurement sample. On the other hand, the release film on one side of the pressure-sensitive adhesive layer obtained in the comparative example was peeled off from the pressure-sensitive adhesive sheet, and then bonded to the same black acrylic resin plate as described above, and then the release film on the other side was peeled off, and the peeled surface was used as a sample for measuring surface reflectance. The surface reflectance (Y value) was measured by a reflectance spectrophotometer (U4100, manufactured by hitachi high technology corporation).

Measurement of internal reflection inhibition ratio (transmittance-improving effect)

The second release film (the side on which the dispersion liquid was applied to the adhesive layer) was peeled off from the adhesive sheet obtained in example, and then the low refractive index layer side of the laminated film having the low refractive index layer having a refractive index of 1.36 formed on the triacetyl cellulose film was laminated on the adhesive layer side thereof, so that the low refractive index adjustment region of the adhesive layer was in contact with the low refractive index layer on the laminated film. Next, the first release film was peeled off, and a slide glass (trade name: white polishing No.1, thickness: 0.8mm to 1.0mm, total light transmittance: 92%, haze: 0.2%, manufactured by Song Nitro Co., ltd.) was attached to the adhesive layer. In this way, a test piece having a layer structure of triacetyl cellulose film/low refractive index layer/adhesive layer (second face is low refractive index layer side)/slide glass was produced. On the other hand, with respect to the adhesive layer obtained in the comparative example, the release film on one side was peeled off from the adhesive sheet, and then a test piece having a layer structure of triacetyl cellulose film/low refractive index layer/adhesive layer/slide glass was produced in the same manner as described above.

Regarding the internal reflection suppression ratio (transmittance improvement effect), the transmittance of the test piece fabricated in the above was measured and calculated based on the following formula. In the following formula, "transmittance without particles (%)" is the reflectance of the test piece of the comparative example. That is, the internal reflection suppressing effect (transmittance improving effect) is an index indicating how much the internal reflectance can be reduced by having the refractive index adjusting layer.

Internal reflection inhibition (%) = "transmittance (%)" - "transmittance (%) in the absence of particles".

In the table 1 of the description of the present invention,

(X1) represents hollow silica nanoparticles: refractive index 1.24 (trade name: THRULYA 5320, particle size 75nm, manufactured by Nitro catalyst Co., ltd.),

(X2) represents hollow polymer particles: refractive index 1.32 (trade name: TECHPOLYMER NH model XX-255AA, particle diameter 80nm, manufactured by water accumulation Co., ltd.),

(X3) represents hollow polymer particles: refractive index 1.33 (trade name: TECHPOLYMER NH model XX-260AA, particle diameter 60nm, manufactured by water accumulation Co., ltd.),

(Y1) represents MgF ₂ :1.38, average primary particle diameter: 40nm, manufactured by CIK NanoTek Co., ltd,

(Y2) represents Na ₃ AlF ₆ :1.34, average primary particle diameter: 50nm, manufactured by CIK NanoTek Co., ltd,

MEK/MIBK means methyl ethyl ketone/methyl isobutyl ketone=9/1 (volume ratio),

ethanol/MIBK means ethanol/methyl isobutyl ketone=9/1 (volume ratio),

IPA represents isopropanol.

Claims

1. An adhesive layer having a first face and a second face on the opposite side of the first face, characterized in that,

the first face having a first refractive index based on the adhesive composition and the second face having a second refractive index lower than the first refractive index of the first face,

a low refractive index material having a refractive index lower than that of the base polymer is dispersed in the adhesive layer on the second face side, and

the thickness of the region in which the low refractive index material is dispersed is 600nm or less in the thickness direction from the second surface side of the adhesive layer.

2. The adhesive layer of claim 1, wherein the difference between the first refractive index of the first face and the second refractive index of the second face is between 0.02 and 0.45.

3. The adhesive layer of claim 1, wherein the second refractive index of the second face is 1.45 or less.

4. The adhesive layer of claim 1, wherein the base polymer has a refractive index of 1.40 to 1.55 and the low refractive index material has a refractive index of 1.10 to 1.45.

5. The adhesive layer of claim 1, wherein the low refractive index material is particles having an average particle diameter of 10nm to 150 nm.

6. The adhesive layer according to claim 1, wherein the low refractive index material is at least one particle selected from the group consisting of inorganic particles, porous silica particles, hollow silica nanoparticles, and hollow polymer particles, the inorganic particles being selected from the group consisting of MgF ₂ 、CaF ₂ And Na (Na) ₃ AlF ₆ At least one of the group consisting of.

7. The adhesive layer of claim 1, wherein the adhesive layer has a total light transmittance of 85% or more.

8. The adhesive layer of claim 1, wherein the second side has a reflectivity of 0.5% to 3.5%.

9. The adhesive layer of claim 1, wherein the difference between the reflectivity of the first side and the reflectivity of the second side is between 0.1% and 3.5%.

10. The adhesive layer of claim 1, wherein the adhesive layer has a gel fraction of 30 wt% to 95 wt%.

11. The adhesive layer according to claim 1, wherein the adhesive layer has a storage modulus G' at 25 ℃ of 0.05MPa to 0.50MPa.

12. The adhesive layer according to any one of claims 1 to 11, wherein the adhesive layer has a tan delta peak value of-5 ℃ to-50 ℃ when measured in dynamic viscoelasticity at 1 Hz.

13. A method for producing the adhesive layer according to any one of claims 1 to 12, comprising the steps of:

14. An adhesive sheet, characterized in that the adhesive sheet has the adhesive layer according to any one of claims 1 to 12 and has a support on one side or both sides of the adhesive layer.

15. An optical film with an adhesive layer, which has an optical film and an adhesive layer provided on one side or both sides of the optical film, characterized in that,

the adhesive layer of one or both sides is the adhesive layer of any one of claims 1 to 12, and the first side of the adhesive layer is provided on the optical film.

16. The adhesive layer-carrying optical film of claim 15, wherein the optical film is a polarizing film.

17. An optical laminate, characterized in that the optical laminate has: the adhesive layer-attached optical film according to claim 15 or 16, and a low refractive index optical member attached to the adhesive layer of the adhesive layer-attached optical film.

18. An image display device having the adhesive layer according to any one of claims 1 to 12, the adhesive layer-attached optical film according to claim 15 or 16, or the optical laminate according to claim 17.