TW201946995A - Adhesive layer, method for producing same, adhesive sheet, adhesive layer-attached optical film, and image display device - Google Patents

Abstract

Provided is an adhesive layer having a first face and a second face which is on the reverse side from the first face, wherein an adhesive composition containing a base polymer forms the base of the entire adhesive layer, 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. This adhesive layer is capable of effectively suppressing 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, or a Fresnel lens, lenticular lens, or microlens film.

Description

Adhesive layer, manufacturing method thereof, adhesive sheet, optical film with adhesive layer, and image display device

The invention relates to an adhesive layer and a manufacturing method thereof. The present invention also relates to an adhesive sheet having the above-mentioned adhesive layer and an optical film with an adhesive layer. Further, the present invention relates to an image display device using the same.

For example, a display device such as a liquid crystal display device or an organic EL (Electroluminescence) display device uses an adhesive composition to combine transparent cover members such as a polarizing film, a retardation film, and a cover glass, and various other optical films with other components. Optical film bonding. In this way, by disposing the adhesive layer between two optical films, an optical film laminate having the two optical films is formed. The optical film laminated body of such a structure is arrange | positioned in a display device, for example so that the side of an optical film may become a visible side. In this configuration, when external light is incident from the optical film on the visible side, the incident light is reflected at the interface between the adhesive layer and the optical film on the non-visible side and returns to the visible side. This problem becomes more significant when the incident angle of external light is small.

On the other hand, for a backlight unit of an image display device, it has been proposed in the industry to use, for example, a light-diffusing adhesive composition containing a (meth) acrylic polymer as a base polymer and containing light-diffusing fine particles (Patent Document 1).
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-224964

[Problems to be solved by the invention]

It is considered that the problems described above arise due to the difference in refractive index between the adhesive layer and the adherend. For example, optical members (e.g., antireflection film, light diffusion film, light guide film) used in the adhesive layer and low refractive index materials such as fluorine-based resins, polysiloxanes, low-refractive inorganic particles, porous materials, and hollow materials , Diaphragm, lens film, Fresnel lens, or lenticular lens or microlens film), the visibility caused by the internal reflection of incident light at the interface will cause problems. This problem is considered because the refractive index of the optical film is lower than that of the adhesive layer. Therefore, it is considered to eliminate the above problem by using an adhesive layer having a lower refractive index. For example, as a method for forming an adhesive layer with a lower refractive index by using an acrylic adhesive, it is considered to use a fluoroalkyl acrylate as a base polymer for a common acrylic polymer (refractive index is usually 1.47 to 1.52). (Refractive index of about 1.38) as a single unit. However, the adhesive layer using a base polymer containing the above-mentioned fluoroalkyl acrylate as a monomer unit having a low refractive index has a high surface tension and it is difficult to ensure adhesion. Thus, 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, light-diffusing fine particles are dispersed throughout the entire range of the adhesive layer, and therefore it is difficult to sufficiently secure the optical film with the optical film. Equal tightness.

An object of the present invention is to provide an effective method for suppressing an optical member having a relatively 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. Adhesive layer with internal reflection and good adhesion and manufacturing method thereof.

In addition, an object of the present invention is to provide an adhesive sheet having the above-mentioned adhesive layer, and further to provide an optical film having the adhesive layer with the adhesive layer, and an object of the present invention is to provide an adhesive sheet having the above-mentioned adhesive layer or Image display device for optical film of adhesive layer.
[Technical means to solve the problem]

The present inventors have intensively studied to solve the above-mentioned problems, and as a result, have discovered an adhesive layer and the like shown below, and completed the present invention.

That is, the present invention relates to an adhesive layer, which is characterized in that it has a first surface and a second surface on the opposite side of the first surface, and the adhesive layer includes an adhesive containing a base polymer. The composition forms a substrate with an entire adhesive layer,
The first surface has a first refractive index based on the adhesive composition, and on the other hand, the second refractive index of the second surface is lower than the first refractive index of the first surface.

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 state in which a low refractive index material having a refractive index lower than the refractive index of the base polymer is dispersed on the second surface side may be adopted.

In the adhesive layer, the thickness of a region in which the low-refractive index material is dispersed is preferably 600 nm or less in the thickness direction from the second surface side of the 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 material 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 material is preferably 0.07 to 0.45.

Examples of the low-refractive material include particles having an average particle diameter of 10 nm to 150 nm.

Examples of the low-refractive material include at least one inorganic particle selected from the group consisting of MgF ₂ , CaF ₂ and Na ₃ AlF ₆ , and a material selected from porous silica particles, hollow nano silica particles, and hollow particles. At least one particle in a group of polymer particles.

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

The reflectance of the second surface of the adhesive layer is preferably 0.5 to 3.5%.

The difference in reflectance between the first surface and 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 elastic modulus G ′ of the adhesive layer at 25 ° C. is preferably 0.05 to 0.50 MPa.

The tan δ peak of the above-mentioned adhesive layer at the time of dynamic viscoelasticity measurement at 1 Hz is preferably -5 to -50 ° C.

In addition, the present invention relates to a method for manufacturing an adhesive layer, which is characterized in that it is a method for manufacturing the above-mentioned adhesive layer, and includes:
Step (1), which uses an adhesive composition containing a base polymer to form a base adhesive layer on a support;
Step (2), which is preparing a dispersion liquid in which a low refractive index material having a refractive index lower than the refractive index of the base polymer is dispersed;
Step (3), which is to apply the above-mentioned dispersion to the second side opposite to the first side of the support side of the base adhesive layer, so that the low-refractive index material contained in the dispersion or solution is from the above The above-mentioned second surface of the base adhesive layer is impregnated with the above-mentioned thickness direction; and step (4) is to dry the adhesive layer after the above-mentioned low refractive index material is impregnated.

In addition, the present invention relates to an adhesive sheet, which is characterized in that it has the above-mentioned adhesive layer and has a support on one or both sides of the adhesive layer.

In addition, the present invention relates to an optical film with an adhesive layer, which is characterized in that it has an optical film and an adhesive layer provided on one or both sides of the optical film, and the above-mentioned one-sided or two-sided adhesive The layer is the above-mentioned adhesive layer, and the first surface side of the adhesive layer is provided on the optical film.

Among the above-mentioned optical films with an adhesive layer, a polarizing film can be preferably used as the optical film.

In addition, the present invention relates to an optical laminated body, which is characterized by having the above-mentioned optical film with an adhesive layer and a low-refractive index optical member adhered to the adhesive layer of the optical film with the adhesive layer.

The present invention also relates to an image display device including the adhesive layer, the optical film with an adhesive layer, or the optical laminate.
[Effect of the invention]

The adhesive layer of the present invention is different from the diffusion adhesive layer in which the fine particles are uniformly diffused in the adhesive layer. The two surfaces of the adhesive layer having one of the first surface and the second surface have different refractive indexes. The side has a first refractive index of the adhesive composition based on the substrate forming the entire adhesive layer, and a second refractive index lower than the first refractive index of the first surface on the opposite side of the second surface. In this way, the adhesive layer of the present invention has an adhesive surface that is controlled to a lower refractive index than the refractive index of the adhesive layer. Therefore, the optical member (for example, anti-reflection film, light Refractive index difference between a diffusion film, a light guide film, a diaphragm, a lens film, a Fresnel lens or a lenticular lens or a microlens film, etc., thereby suppressing the interface between the adhesive layer and the optical member Reflection, and contribute to the improvement of light extraction efficiency. When the second surface of the adhesive layer of the present invention is applied to a surface unevenness portion such as a microlens, the surface unevenness portion can be protected by filling the surface unevenness portion with the adhesive layer, and the surface unevenness can be protected. Compared with the case where a void layer is provided in the concave-convex shape portion, the void can be filled without impairing the light extraction efficiency, and damage and shape damage caused by vibration or the like during use or transportation 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 total light transmittance is high, and a low refractive index region can be formed without increasing the haze value. In addition, the first surface of the adhesive layer of the present invention maintains the original adhesive force of the adhesive layer, so it has good adhesion with ordinary optical films (such as polarizing films, etc.). On the other hand, it is controlled to have a low refractive index. On the second side of the adhesive layer having a high ratio, the adhesive composition forms a substrate, and therefore, it can also ensure the adhesion with an optical film formed of a low refractive index material.

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 surface f1 and a second surface f2 on the side opposite to the first surface f1. In addition, in the above-mentioned adhesive layer 1, the entire substrate (matrix) 1 a of the 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 n1. FIG. 1 illustrates a case where the low refractive index material 2 having a refractive index lower than the refractive index of the base polymer is dispersed (existing in a bias) on the side of the second surface f2 in the substrate 1a.

The first refractive index n1 of the first surface f1 is equivalent 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 1a. Furthermore, the refractive index of the base polymer is substantially the same as the refractive index of the adhesive layer 1 of the entire substrate 1a of the adhesive layer 1. Therefore, the first refractive index n1 of the first surface f1 is substantially the refractive index of the base polymer. Decide. The adhesive composition forming the adhesive layer is described below. For example, the refractive index of an adhesive layer formed by a representative acrylic adhesive is usually about 1.47 to 1.52. The refractive index of the adhesive layer formed by the silicone-based adhesive is usually about 1.40.

On the other hand, the relationship between the second refractive index n2 of the second surface f2 and the first refractive index n1 of the first surface f1 side is not particularly limited as long as n1> n2 is satisfied, and it can be considered to be an adherend. The refractive index of the low-refractive-index optical film is appropriately determined. However, it is also considered that if the difference (n1-n2) between the first refractive index n1 and the second refractive index n2 is too large, internal reflection in the adhesive layer 1 will occur, so the front difference (n1-n2) is preferably adjusted. To 0.02 to 0.45. The difference (n1-n2) is more preferably 0.03 to 0.35, and still more preferably 0.03 to 0.25.

In terms of effectively suppressing internal reflection, 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 even more preferably 1.3 or less. . If the second refractive index n2 is 1.4 or less, the second surface side of the adhesive layer 1 of the present invention can also be used as an alternative use of the air layer. On the other hand, from the viewpoint of maintaining the adhesive force, the second refractive index n2 is preferably 1.25 or more, and more preferably 1.28 or more. The range of the second refractive index n2 is a lower range than the lower limit of the refractive index (usually about 1.47 to 1.52) of the adhesive layer formed by a representative acrylic adhesive.

When the low-refractive-index material 2 is dispersed on the second surface f2 in the adhesive layer 1 as shown in FIG. 1, a base polymer in the adhesive composition of the substrate 1 a is formed. The refractive index is 1.40 to 1.55. In the substrate 1a, the refractive index of the low refractive index material 2 dispersed on the side of the second surface a2 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 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 material 2 is more preferably 0.07 to 0.35, and still more preferably 0.10 to 0.30. Although the lower refractive index of the above low refractive index material 2 can reduce the refractive index at a low addition amount, on the other hand, the refractive index of the base polymer (adhesive layer 1a) and the refractive index of the above low refractive index material 2 exist. Since the difference tends to be large and scattering (haze) tends to occur, the refractive index difference is preferably adjusted so as not to be too large. When the above-mentioned refractive index is made of a single-layer film, it can be expressed as a refractive index value of D line measured by a spectroscopic ellipsometry at 23 ° C.

As the low refractive index material 2, particles having an average particle diameter of 10 nm to 150 nm can be used. When the particles with an average particle diameter in the above range are dispersed on the second surface f2 side of the adhesive layer 1, it is also suitable for suppressing the haze of the adhesive layer 1 and maintaining a high total light transmittance. The average particle diameter is preferably 20 nm to 100 nm, and more preferably 20 nm to 90 nm. The average particle diameter of the particles is a value measured by a particle size distribution diameter measuring device using a dynamic light scattering method.

Examples of the low-refractive material 2 include MgF ₂ (refractive index 1.38), CaF ₂ (refractive index 1.43: fluorite), Na ₃ AlF (refractive index 1.34: sodium hexafluoroaluminate (cryolite)), and the like. These materials (for example, particles) may be used singly or in combination of two or more kinds.

As the low-refractive material 2, hollow particles can be used, for example. The hollow particles may be either inorganic particles or polymer particles. The hollow particles have void spaces with a relatively low refractive index within the particles, so the refractive index of the hollow particles is lower than the refractive index of the components forming the hollow particles. For example, the refractive index of silicon oxide is 1.46, but hollow nanometer silica particles (refractive index 1.24, trade name: Thrulya5320, particle size 75 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.), and porous silica particles can be used Low-reduction material. Further, hollow polymer fine particles (refractive index 1.32, trade name: Techpolymer NH, model XX-255AA, particle diameter 80 nm, hollow ratio 39%, manufactured by Sekisui Plastics Co., Ltd.) can be exemplified. In addition, when the hollow particles are provided on a low-refractive surface treatment layer, since they are hollow materials, there are problems in strength and scratch resistance. However, in the present invention, the hollow particles (low-refractive material 2) have problems. It is a form of being added (impregnated) to the adhesive layer 1, so it can be applied without considering the problems of strength and scratch resistance.

In addition, as the low-refractive material 2, an oligomer containing a fluoroalkyl group, an oligomer containing a polysiloxane resin, or the like can be used.

The thickness of the adhesive layer 1 is not particularly limited, but is usually 5 μm to 500 μm, preferably 10 μm to 400 μm, and further preferably 10 μm to 350 μm. Further, in FIG. 1, a 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 usually preferably 600 nm or less, more preferably 300 nm or less, and still more preferably 200 nm or less. Furthermore, in order to effectively suppress internal reflection when applied to an optical film having a low refractive index, the thickness T is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more.

The region of thickness T in the adhesive layer 1 in which the low refractive index material 2 is dispersed becomes an irregular uneven shape in the relationship with the substrate (matrix) 1a. In the present invention, the thickness T is calculated by calculating the uneven shape Determined by the average of the measured values of the depth.

The low-refractive-index material 2 is distributed on the side of the second surface f2 in a single dispersed state or a partially aggregated state. As described with reference to FIG. 1, the boundary between the area where the low refractive index material 2 is dispersed and the substrate 1 a where the low refractive index material 2 is not dispersed becomes an irregular uneven shape. When measuring the thickness T, it will be at each measurement position. The range of the depth of 90% of the low refractive index material 2 is used as the measurement value of the thickness T of the measurement position, and the average of the measurement values of the plurality of measurement positions is calculated.

FIG. 2 is a plan view showing a state of the second surface f2 of the adhesive layer 1. As shown in FIG. 2, the island structure in which the low refractive index material 2 is dispersed in an island shape on the substrate 1 a includes a portion of the substrate 1 a and a portion of the low refractive index material 2. The area of the low-refractive-index material 2 in the second surface f2 is preferably set to a range of 30 to 99%. The area ratio is the ratio of the area occupied by the low refractive index material 2 to the overall area of the square area in a square area with a side of 10 μm to 200 μm. The square area is measured and the measured value is calculated. The area ratio is calculated by averaging the numbers.

Furthermore, regarding the ratio of the low refractive index material 3 in the adhesive layer 1, as long as the first refractive index n1 on the first surface f1 side and the second refractive index n2 on the second surface f2 satisfy the relationship of n1> n2 There are no particular restrictions.

The total light transmittance of the entire adhesive layer 1 of the present invention is preferably 85% or more, further preferably 88% or more, and even more preferably 90% or more. The higher the total light transmittance of the adhesive layer 1, the better. 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, the better. The total light transmittance and haze value of the entire adhesive layer 1 are values measured in accordance with JIS K7361.

The reflectance of the second surface of the adhesive layer 1 of the present invention is preferably 0.5 to 3.5%. The reflectance of the second surface of the adhesive layer 1 of the present invention is lower than the reflectance of the first surface. In the relationship with the low refractive index material, the internal surface reflection can be controlled to be small. It is preferably 0.5 to 3.0%, and further preferably 0.5 to 2.5%. The difference in reflectance between the first surface and the second surface of the adhesive layer 1 of the present invention is preferably 0.1 to 3.5%.

Furthermore, although the adhesive layer 1 of the present invention is described above on the premise that the second refractive index n2 of the second surface f2 is designed to be lower than the first refractive index n1, the adhesive layer 1 of the present invention may be It is understood as an invention having the following characteristics: in addition to being able to specify the relationship between the refractive indices of the two surfaces, the reflectance of the second surface f2 is lower than the reflectance of the first surface f1.

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% by weight, more preferably 35 to 90% by weight, and even more preferably 40 to 90% by weight. If the gel fraction of the said adhesive layer 1 exists in the said range, it will become suitable for having a stress relaxation property and ensuring the followability to unevenness | corrugation. In addition, the above-mentioned gel fraction is related to the substrate 1 a in the adhesive layer 1 and does not include the low refractive index material 2.

＜ Measurement of gel fraction of adhesive layer ＞
About 0.2 g of the self-adhesive layer (before the penetration of the low refractive index material) was scraped to obtain Sample 1. The above-mentioned sample 1 was wrapped with a Teflon (registered trademark) film (trade name "NTF1122", manufactured by Nitto Denko Corporation) having a diameter of 0.2 μm, and was bundled with a kite thread, and this was used as sample 2. The weight of Sample 2 before the following test was measured, and it was set to weight A. The weight A is the total weight of Sample 1 (adhesive layer), Teflon (registered trademark) film, and kite string. The total weight of the Teflon (registered trademark) film and the kite string was defined as the weight B. Next, the above-mentioned sample 2 was put into a 50 ml container filled with ethyl acetate, and left at 23 ° C for 1 week. Thereafter, the sample 2 was taken out from the container, and dried at 130 ° C for 2 hours in a dryer to remove ethyl acetate, and then the weight of the sample 2 was measured. The weight of Sample 2 after the above test was measured, and it was set to weight C. Then, the gel fraction (% by weight) was calculated from the following formula.
Gel fraction (% by weight) = (C－B) / (A－B) × 100

The storage elastic modulus G 'of the adhesive layer 1 of the present invention at 25 ° C is preferably 0.05 to 0.50 MPa. The storage elastic modulus G ′ is preferably 0.06 to 0.45 MPa, more preferably 0.07 to 0.40 MPa, and even more preferably 0.08 to 0.35 MPa. If the storage elastic modulus G 'of the above-mentioned adhesive layer 1 is within the above-mentioned range, it will be suitable for the protection of image display devices (LCD, OLED terminals, etc.) that are suitable for thinning, and ensure the dimensional stability during cutting Appearance.

The tan δ peak value (glass transition temperature) of the adhesive layer 1 of the present invention during dynamic viscoelasticity measurement at 1 Hz is preferably -5 to -50 ° C. The tan δ peak is preferably -7 to -50 ° C, more preferably -9 to -45 ° C, and even more preferably -10 to -40 ° C. If the tan δ peak value of the adhesive layer 1 is within the above range, it will be suitable for ensuring the drop resistance of the image display device (mobile terminal, etc.).

<Measurement of the storage elastic modulus G 'and tanδ peak of the adhesive layer>
A plurality of adhesive layers were laminated to produce a test sample having a thickness of about 2 mm. This test sample was punched into a disc shape with a diameter of 7.9 mm, sandwiched into a parallel plate, and the "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific was used to perform dynamic viscoelasticity in accordance with the following conditions. Measurement. From the measurement results, the storage elastic modulus G 'and tan δ peaks of the adhesive layer at 25 ° C were read.
(Measurement conditions)
Frequency: 1 Hz
Deformation mode: bending and torsion temperature: -70 ℃ ～ 150 ℃
Heating rate: 5 ° C / min

Next, a manufacturing method of 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 by an adhesive composition containing a base polymer. The base adhesive layer 1 'forms the substrate 1a in the obtained adhesive layer 1. The support side of the base adhesive layer 1 'is a first surface f1', and the opposite side thereof is a second surface f2 '. The method for forming the base adhesive layer 1 'is not particularly limited, and it can be formed by a method commonly used in the art. Specifically, the adhesive composition may be formed on one surface of the support S, and a coating film formed from the adhesive composition may be dried and formed, or may be formed 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 materials of the release film include resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; porous materials such as paper, cloth, and non-woven fabrics; Suitable sheets, such as foam sheets, metal foils, and laminates thereof, and the like; in terms of excellent surface smoothness, a resin film can be preferably used. If necessary, the above-mentioned release film may be subjected to release and antifouling treatment or antistatic treatment.

On the other hand, as step (2), a dispersion liquid 10 is prepared which disperses the low-refractive-index material 2 having a refractive index lower than that of the base polymer used in the above-mentioned adhesive composition. (Not shown). As the dispersion medium for the dispersion liquid, an adhesive that can disperse the low refractive index material 2 and can penetrate the base adhesive layer 1 'can be used, and an adhesive that can form the base adhesive layer according to the type of the low refractive index material The type of composition is selected in a timely manner. The concentration of the low refractive index material in the dispersion medium is preferably adjusted to 0.1 to 10% by weight, for example.

Examples of the dispersion medium include methanol, ethanol, isopropanol, 1-propanol, n-butanol, 2-butanol, cyclohexanol, third butanol, glycerol, ethylene glycol, and 2-methyl. -2,4-pentanediol, phenol, p-chlorophenol and other alcohols; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 2-hexanone , 2-heptanone and other ketones; diethyl ether, tetrahydrofuran, dioxane, anisole and other ethers; ethyl acetate, butyl acetate, methyl lactate and other esters; benzene, toluene, xylene and other aromatic hydrocarbons Type; aliphatic hydrocarbons such as n-hexane, cyclohexane; fluorenamines such as dimethylformamide, dimethylacetamide; methyl cellosolve, ethyl cellosolve, methyl acetate cellosolve Other fibrinolytic agents. These dispersion media can be used alone or in combination of two or more. In addition, the said solvent is an illustration and the solvent used by this invention is not limited to these.

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 removed from the base adhesive layer. The second surface f2 'of 1' permeates in the thickness direction. (3) -1 in FIG. 3 shows a state immediately after the dispersion liquid 10 is coated on the base adhesive layer 1 ′, and (3) -2 shows a state in which the low-refractive index material 2 has penetrated into the base adhesive layer 1 ′. The side of the above-mentioned second surface f2 'of the base adhesive layer 1' is swelled by the dispersion medium of the dispersion liquid 10, and the low-refractive index material 2 in the dispersion liquid 10 penetrates into the base adhesive layer 1 'in the process.

Next, as step (4), the base adhesive layer 1 'after the low refractive index material 2 is impregnated is dried. Through the drying step, the dispersion medium of the dispersion liquid 10 impregnated in the base adhesive layer 1 ′ can be evaporated to obtain the adhesive layer 1 shown in FIG. 1. This state is shown in (4) of FIG. 3. The conditions of the drying step can be determined according to the type of the dispersion medium.

The relationship between the adhesive composition of the region (thickness T) in which the low refractive index material 2 is dispersed in the adhesive layer 1 to form the base adhesive layer 1 ′ and the dispersion medium of the dispersion liquid 10 is determined. The dispersion medium is appropriately selected so that the above-mentioned penetration depth becomes the above-mentioned value. Moreover, the application amount of the dispersion liquid can be appropriately set so as to have a desired thickness T.

The coating method of the dispersion liquid may be, for example, roll coating, contact roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, blade coating, air knife coating. , Shower curtain coating, lip mold coating, die nozzle coating machine and other appropriate methods. The thickness T can be controlled by a coating method of the dispersion liquid, a concentration of the dispersion liquid, an application amount, and the like.

＜ Adhesive composition ＞
The adhesive composition containing the base polymer which forms the base sheet (matrix) 1a of the adhesive layer 1 of this invention is demonstrated.

As the above-mentioned adhesive composition, a transparent material having adhesiveness which can be used for optical applications can be preferably used. Examples of the adhesive composition include acrylic adhesives, rubber-based adhesives, silicone-based adhesives, polyester-based adhesives, urethane-based adhesives, epoxy-based adhesives, and polyethers. The system adhesive is appropriately selected and used. From the viewpoints of transparency, processability, and durability, it is preferable to use an acrylic adhesive. A base polymer corresponding to the kind of the above-mentioned adhesive composition can be used. In the present invention, an acrylic adhesive containing a (meth) acrylic polymer as a base polymer is preferred.

The acrylic pressure-sensitive adhesive may include, for example, a partial polymer containing a monomer component of an alkyl (meth) acrylate, and / or a (meth) acrylic polymer obtained from the monomer component. The base polymer of the acrylic adhesive contains a partial polymer containing a monomer component of an alkyl (meth) acrylate and / or a (meth) acrylic polymer obtained from the monomer component.

Examples of the (meth) acrylic acid alkyl ester include the linear or branched (meth) acrylic acid alkyl esters having 1 to 24 carbon atoms, and among them, 1 to 9 carbon atoms are preferred. As the (meth) acrylic acid alkyl ester, a branched (meth) acrylic acid alkyl ester having 4 to 9 carbon atoms can be preferably exemplified. This (meth) acrylic acid alkyl ester is suitable from the point that the balance of adhesive characteristics is easy to be obtained. Specific examples of the branched (meth) acrylic acid alkyl ester having 4 to 9 carbon atoms include n-butyl (meth) acrylate, second butyl (meth) acrylate, and (meth) acrylic acid. Tert-butyl ester, isobutyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, ( 2-ethylhexyl methacrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and the like can be used alone or in combination of two or more.

In the present invention, the total amount of the (meth) acrylic acid alkyl ester having an alkyl group at the ester end of the carbon number of 1 to 24 is smaller than the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It is preferably at least 40% by weight, more preferably at least 50% by weight, and even more preferably at least 60% by weight.

The monomer component may contain a comonomer other than the alkyl (meth) acrylate as the monofunctional monomer component. A comonomer can be used as a residue of the said alkyl (meth) acrylate in a monomer component.

Examples of the comonomer include a cyclic nitrogen-containing monomer. As the cyclic nitrogen-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acrylfluorenyl group or a vinyl group and having a cyclic nitrogen structure can be used without particular limitation. The cyclic nitrogen structure is preferably one having a nitrogen atom in the cyclic structure. Examples of the cyclic nitrogen-containing monomer include: lactamamine-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinyl Vinyl monomers having a nitrogen-containing heterocyclic ring, such as pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperidine, vinylpyridine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylline, and the like. In addition, (meth) acrylic monomers containing heterocyclic rings such as a phthaloline ring, a piperidine ring, a pyrrolidine ring, and a piperidine ring are mentioned. Specific examples include N-acrylic hydrazine, N-acrylic fluorenylpiperidine, N-methacryl hydrapiperidine, N-acrylic fluorenyl pyrrolidine, and the like. Among the cyclic nitrogen-containing monomers, a lactamamine-based vinyl monomer is preferred.

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

The monomer component used in the present invention may contain a hydroxyl-containing monomer as a monofunctional monomer component. As the hydroxyl-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acrylfluorenyl group or a vinyl group, and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3- Hydroxypropyl ester, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, (formyl) Hydroxy) (meth) acrylic acid hydroxyalkyl esters such as 12-hydroxylauryl acrylate; and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate hydroxyalkyl cycloalkyl (meth) acrylates. Other examples include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. They can be used alone or in combination. Among these, a hydroxyalkyl (meth) acrylate is preferable.

In the present invention, in terms of improving the adhesion and cohesion, the total amount of the above-mentioned hydroxyl-containing monomers relative to the monofunctional monomer component forming the (meth) acrylic polymer is preferably 1% by weight or more. , More preferably 2% by weight or more, even more preferably 3% by weight or more. On the other hand, if the above-mentioned hydroxyl-containing monomer is too much, the adhesive layer may be hardened and the adhesive force may be reduced. In addition, the viscosity of the adhesive composition may be excessively high or the gelation may occur. The total amount of the hydroxyl monomers relative to the total amount of the monofunctional monomer components forming the (meth) acrylic polymer is preferably 30% by weight or less, more preferably 27% by weight or less, and even more preferably 25% by weight or less.

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

As the carboxyl group-containing monomer, a polymerizable functional group having an unsaturated double bond, such as a (meth) acrylfluorenyl group or a vinyl group, and a carboxyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, butenoic acid, and isobutylene Acids and the like can be used alone or in combination. Iconic acid and maleic acid can be used as their anhydrides. Among these, acrylic acid and methacrylic acid are preferred, and acrylic acid is particularly preferred. In addition, a carboxyl group-containing monomer may be used arbitrarily in the monomer component used for manufacture of a (meth) acrylic-type polymer of this invention, On the other hand, a carboxyl group-containing monomer may not be used.

As the monomer having a cyclic ether group, a polymerizable functional group having an unsaturated double bond such as a (meth) acrylfluorenyl group or a vinyl group can be used without particular limitation, and it may have an epoxy group or an oxetane group. Cyclic ether groups. Examples of the epoxy-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexyl methyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate glycidyl ether. . Examples of the oxetanyl monomer include 3-oxetanyl (meth) acrylate, 3-methyl-oxetanyl (meth) acrylate, ( 3-ethyl-oxetanyl (meth) acrylate, 3-butyl-oxetanyl (meth) acrylate, 3-hexyl-oxetan (meth) acrylate Alkyl methyl esters and the like. They can 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 with respect to the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It is preferably 27% by weight or less, and further preferably 25% by weight or less.

Among the monomer components forming the (meth) acrylic polymer of the present invention, examples of the comonomer include CH ₂ = C (R ¹ ) COOR ² (where R ¹ represents hydrogen or methyl, and R ² represents A substituted (alkyl, cyclic cycloalkyl) group having 1 to 3 carbon atoms is an alkyl (meth) acrylate.

Here, as a substituent of R ² that is a substituted alkyl group having 1 to 3 carbon atoms, an aryl group having 3 to 8 carbon atoms or an aryloxy group having 3 to 8 carbon atoms is preferred. The aryl group is not limited, and a phenyl group is preferred.

Examples of the monomer represented by such CH ₂ = C (R ¹ ) COOR ² include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, and cyclohexyl (meth) acrylate. , 3,3,5-trimethylcyclohexyl (meth) acrylate, isopropyl (meth) acrylate, and the like. They can be used alone or in combination.

In the present invention, with respect to the total amount of the monofunctional monomer components forming the (meth) acrylic polymer, 50% by weight or less of the above-mentioned (A) represented by CH ₂ = C (R ¹ ) COOR ² may be used. It is 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, vinyl acetate, vinyl propionate, styrene, α-methylstyrene can also be used; polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, forma Alcohol-based acrylate monomers such as oxyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate; tetrahydrofuran methyl (meth) acrylate, fluoro (meth) acrylate, silicone (Meth) acrylic acid esters or acrylic acid monomers such as 2-methoxyethyl acrylate; and fluorene-amine-containing monomers, amine-containing monomers, fluorenimine-containing monomers, N-acrylamidoline, Vinyl ether monomer, etc. As the comonomer, a monomer having a cyclic structure such as a terpene (meth) acrylate and a dicyclopentyl (meth) acrylate can be used.

Further, examples thereof include a silane-based monomer containing a silicon atom. Examples of the silane-based monomer include 3-propenyloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4 -Vinyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloxydecyltrimethoxysilane, 10-propylene Ethoxydecyltrimethoxysilane, 10-methacryloxydecyltriethoxysilane, 10-propenyloxydecyltriethoxysilane, 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 necessary in order to adjust the cohesiveness of the adhesive composition.

A polyfunctional single system monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acrylfluorenyl group or a vinyl group, and examples thereof include (poly) ethylene glycol di (methyl) Acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (methyl) Acrylate), 1,2-ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylic acid Ester compounds of polyhydric alcohols such as esters, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, and (meth) acrylic acid; allyl (meth) acrylate, ( Vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, acrylic polyester, urethane acrylate, butyl di (meth) acrylate, hexyl di (meth) acrylate, and the like. Among them, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. The polyfunctional monomer may be used singly or in combination of two or more kinds.

The amount of the polyfunctional monomer varies depending on the molecular weight, the number of functional groups, etc., and is preferably 3 parts by weight or less, more preferably 2 parts by weight or less with respect to 100 parts by weight of the total of the monofunctional monomer. It is preferably 1 part by weight or less. The lower limit value is not particularly limited, but is preferably 0 parts by weight or more, and more preferably 0.001 parts by weight or more. When the use amount of the polyfunctional monomer is within the above range, the adhesion force can be improved.

For the production of the (meth) acrylic polymer, known publicly known production methods such as radiation polymerization such as solution polymerization, ultraviolet (UV) polymerization, block polymerization, and emulsion polymerization can be appropriately selected. The obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, and a graft copolymer.

In addition, in the present invention, it is also possible to preferably use a part of the polymer of the monomer component.

For the production of the (meth) acrylic polymer, known publicly known production methods such as radiation polymerization such as solution polymerization, ultraviolet (UV) polymerization, block polymerization, and emulsion polymerization can be appropriately selected. The obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, and a graft copolymer.

When the (meth) acrylic polymer is produced by radical polymerization, a polymerization initiator, a chain transfer agent, an emulsifier, and the like for radical polymerization may be appropriately added to the monomer components to perform the polymerization. polymerization. The above-mentioned polymerization initiator, chain transfer agent, emulsifier and the like for radical polymerization are not particularly limited, and can be appropriately selected and used. In addition, the weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator, the chain transfer agent used, and the reaction conditions, and the amount used can be appropriately adjusted according to the types thereof.

For example, in a solution polymerization or the like, as the polymerization solvent, for example, ethyl acetate, toluene, or the like can be used. As a specific solution polymerization example, a polymerization initiator can be added under an inert gas flow such as nitrogen, and the reaction is usually performed under reaction conditions of about 50 to 70 ° C. and about 5 to 30 hours.

When the (meth) acrylic polymer is produced by radiation polymerization, the monomer component can be produced by irradiating the monomer component with radiation such as an electron beam and ultraviolet (UV). When UV polymerization is performed, it is preferred that the monomer component contains a photopolymerization initiator in terms of advantages such as shortening the polymerization time.

(Silane coupling agent)
Furthermore, the adhesive composition of the present invention may contain a silane coupling agent. The blending amount of the silane coupling agent is preferably 1 part by weight or less, more preferably 0.01 to 1 part by weight, and even more preferably 0.02 based on 100 parts by weight of the base polymer (for example, the (meth) acrylic polymer). ~ 0.6 parts by weight.

(Crosslinking agent)
The adhesive composition of the present invention may contain a crosslinking agent. Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a silicone-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a silane-based crosslinking agent, and an alkyl group. Cross-linking agents such as etherified melamine-based cross-linking agents, metal chelate-based cross-linking agents, and peroxides. The crosslinking agents may be used singly or in combination of two or more kinds. Among these, an isocyanate-based crosslinking agent can be preferably used.

The above-mentioned crosslinking agents may be used singly or in combination of two or more kinds. The total content is preferably 5 parts by weight based on 100 parts by weight of the monofunctional monomer component forming the (meth) acrylic polymer. Hereinafter, it is more preferably 0.01 to 5 parts by weight, still more preferably 0.01 to 4 parts by weight, and even more preferably 0.02 to 3 parts by weight.

(Other additives)
In addition to the above-mentioned components, the adhesive composition of the present invention may contain appropriate additives depending on the application. Examples thereof include viscosity modifiers, peeling modifiers, and adhesion-imparting agents (for example, those containing turpentine derivative resins, polyterpene resins, petroleum resins, oil-soluble phenol resins, etc. that are solid, semi-solid, or liquid at room temperature), Plasticizer, softener , pigment, colorant (pigment, dye, etc.), pH adjuster (acid or alkali), rust inhibitor, anti-aging agent, antioxidant, light stabilizer, ultraviolet absorber, etc.

The adhesive sheet of the present invention has the above-mentioned adhesive layer 1 and has a support on one or both sides of the adhesive layer 1. FIG. 4 shows a case where a support 3a is provided on the first surface f1 of the adhesive layer 1 and a support 3b is provided on the second surface f2. The supports 3a and 3b can be the same as the support S used in the adhesive layer 1 shown in FIG. The support 3a can be directly used as the support S used in the method for manufacturing the adhesive layer 1 shown in FIG. 3. The support 3b can be appropriately provided on the second surface f2 of the adhesive layer 1 after the adhesive layer 1 is manufactured by the manufacturing method shown in FIG. 3.

The optical film A with an adhesive layer of the present invention includes an optical film 4 and an adhesive layer 1 provided on one or both sides of the optical film 4. The above-mentioned adhesive layer 1 may be provided on one side or both sides of the optical film 4. Regarding the adhesive layer 1, the first surface f1 side of the adhesive layer 1 may be provided on the optical film 4. When the adhesive layer 1 is provided on one side of the optical film 4, a general 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 second surface f2 of the adhesive layer 1 has a support 3b.

＜ Optical film ＞
As the optical film, for example, a creator of an image display device such as a liquid crystal display device can be used, and the type is not particularly limited. Examples of the optical film include a polarizing film. A polarizing film is generally used for one or both sides of a polarizing element having a transparent protective film.

<Polarizing film>
Examples of the polarizing film include those having a transparent protective film on at least one side of the polarizing element.

The polarizing element is not particularly limited, and various polarizing elements can be used. Examples of the polarizing element include a dichroic substance that adsorbs iodine or a dichroic dye to a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, and the like. A hydrophilic polymer film that is uniaxially stretched; a polyene-based alignment film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizing element containing a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferred. The thickness of these polarizers is not particularly limited, but is usually about 5 to 80 μm.

A polarizing element obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching the polyvinyl alcohol-based film can be dyed by immersing in an aqueous solution of iodine, for example, and stretched to 3 to 7 times the original length. Production. If necessary, it may be immersed in an aqueous solution which may contain boric acid, potassium iodide, or the like such as zinc sulfate or zinc chloride. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, the dirt or anti-caking agent on the surface of the polyvinyl alcohol-based film can be washed. In addition, swelling of the polyvinyl alcohol-based film can also prevent uneven dyeing and unevenness. The effect. It can be extended after dyeing with iodine, and can be extended while dyeing, or it can be dyed with iodine after extension. It can also be extended in an aqueous solution such as boric acid or potassium iodide or in a water bath.

In the present invention, a thin polarizing element having a thickness of 10 μm or less may be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizing element has less variation in thickness, excellent visibility, and less dimensional change, so it has excellent durability, and it is also preferable as a thickness of a polarizing film in terms of achieving thinness.

As the thin polarizing element, representative examples include Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, International Publication No. 2010/100917, and Japanese Patent No. 4751481. Or the thin polarizing film described in Japanese Patent Laid-Open No. 2012-073563. These thin polarizing films can be produced by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) layer and a stretching resin substrate in a state of a laminate, and a step of dyeing the thin-film. obtain. According to this manufacturing method, even if the PVA-based resin layer is thin, since it is supported by the resin base material for stretching, stretching can be performed without causing abnormalities such as breakage caused by stretching.

As the thin polarizing film described above, in terms of being capable of being stretched at a high magnification and improving polarizing performance, in a manufacturing method including a step of stretching in a state of a laminated body and a step of dyeing, it is preferable to use a method such as International It is particularly preferable to obtain a method of manufacturing a method including a step of extending in a boric acid aqueous solution described in Japanese Patent No. 2010/100917, Japanese Patent No. 4751481 or Japanese Patent Laid-Open No. 2012-073563, and it is particularly preferred to use a Japanese patent It is obtained by a manufacturing method described in the specification No. 4751481 or Japanese Patent Laid-Open No. 2012-073563, which includes a step of assisting in-air stretching before the stretching in a boric acid aqueous solution.

As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture blocking property, and isotropy can be used. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate, polyester resins, polyether resins, polyfluorene resins, polycarbonate resins, polyamide resins, polyimide resins, and polyimide resins. Olefin resin, (meth) acrylic resin, cyclic polyolefin resin (norylene resin), polyarylate resin, polystyrene resin, polyvinyl alcohol resin, and mixtures thereof. Furthermore, on one side of the polarizing element, a transparent protective film is bonded by an adhesive layer. On the other side, (meth) acrylic, urethane, and acrylic urethane can be used. As a transparent protective film, thermosetting resins such as epoxy, silicone, and ultraviolet curing resins are used. The transparent protective film may contain one or more of any appropriate additives. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, coloring inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. 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, and even more preferably 70 to 97% by weight. When the content of the above-mentioned thermoplastic resin in the transparent protective film is 50% by weight or less, there is a possibility that the thermoplastic resin cannot sufficiently express the originally high transparency and the like.

The thickness of the transparent protective film can be appropriately determined, and it is usually about 1 to 500 μm in terms of workability such as strength and workability, and film properties.

A functional layer such as a hard coat layer, an anti-reflection layer, and an anti-adhesive layer may be formed on the surface of the transparent protective film that is not attached to the polarizing element, or it may be formed by performing a treatment for the purpose of diffusion and anti-glare.

The adhesive used for bonding the polarizing element and the transparent protective film is not particularly limited as long as it is optically transparent, and various forms such as water-based, solvent-based, hot-melt, radical-curing, and cation-curing can be used. It is preferably an aqueous adhesive or a radical curing adhesive.

In addition, examples of the optical film include a reflection plate or a retroreflective plate, a retardation film (including a wavelength plate such as 1/2 or 1/4), a vision compensation film, and a brightness enhancement film. Of the optical layer. These can be used alone as an optical film, or in addition to the above-mentioned polarizing film, one layer or two or more layers can be used in practical applications. It is also possible to use a retardation film as the transparent protective film. The retardation film can be appropriately used depending on the purpose, which is obtained by extending or contracting a polymer film, or by orienting and fixing a liquid crystal material.

Although the optical film obtained by laminating the above-mentioned optical layer on a polarizing film can also be formed by sequentially laminating them in the manufacturing process of a liquid crystal display device, etc., those who have been laminated in advance to make an optical film have quality stability and assembly. It is excellent in work and the like and can improve the advantages of manufacturing steps of the liquid crystal display device and the like. An appropriate bonding member such as an adhesive layer can be used in the buildup. When the above-mentioned polarizing film is bonded to other optical layers, their optical axes can be set to an appropriate arrangement angle according to the target phase difference characteristic and the like.

The optical multilayer body B of the present invention has an optical film A with an adhesive layer and a low refractive index optical member 5 attached to the adhesive layer 1 of the optical film A with the adhesive layer. The optical member 5 is provided on the second surface f2 side of the adhesive layer 1. The optical laminated body B shown in FIG. 6 illustrates a case where the optical member 5 is bonded to the adhesive layer 1 after the support 3 b (for example, a release film) is peeled off from the optical film A with the adhesive layer described in FIG. 5. . Examples of the optical member 5 include an antireflection film, a light diffusion film, a diaphragm, a light guide film, a lens film, a Fresnel lens, a lenticular lens, or a microlens film.

The optical film or optical laminate with the adhesive layer of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The formation of the liquid crystal display device can be performed as before. That is, a liquid crystal display device can generally be formed by appropriately assembling and assembling a driving circuit or the like, such as a display panel of a liquid crystal cell and an optical film with an adhesive layer, or an optical laminate, and a lighting system that meets the needs, etc. In the present invention, there is no particular limitation except that the optical film or optical laminate with the adhesive layer obtained by the present invention is used, and it can be as before. For the liquid crystal cell, for example, a TN (Twisted Nematic) type or an STN (Super Twisted Nematic) type, a π type, a VA (Vertical Alignment) type, or an IPS (In-Plane) type can be used. Switching, coplanar switching), and any other type.

It can be formed on one or both sides of a display panel such as a liquid crystal cell with a liquid crystal display device with an adhesive film or an optical laminate with an adhesive layer, or a suitable liquid crystal display device such as a backlight or a reflection plate in a lighting system . In this case, the optical film or optical laminated body with the adhesive layer obtained by the present invention can be disposed on one side or both sides of a display panel such as a liquid crystal cell. When the optical film is provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, a suitable layer such as a diffusion layer, an anti-glare layer, an anti-reflection film, a protective plate, a fluorene array, a lens array plate, a light diffusion sheet, and a backlight can be arranged at an appropriate position. Or more than 2 layers.
[Example]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited to these examples. In addition, parts and% in each case are a basis of weight. All room temperature storage conditions below are 23 ° C and 65% RH.

(Release film)
A polyester film (trade name: DIAFOIL MRF, manufactured by Mitsubishi Resins Co., Ltd.) having a thickness of 38 μm after peeling treatment with silicone on one side was used.

Comparative Example 1
(Preparation of Adhesive Composition (A))
41 parts by weight of 2-ethylhexyl acrylate (2EHA), 41 parts by weight of octadecyl acrylate (ISTA), 14 parts by weight of N-vinyl-2-pyrrolidone (NVP), and N-2-acrylate 4 parts by weight of hydroxybutyl ester (4HBA), 0.035 parts by weight of two photopolymerization initiators (trade name: Irgacure184, manufactured by BASF), and 0.035 parts by weight of photopolymerization initiator (trade name: Irgacure651, manufactured by BASF) A flask was used to prepare a monomer mixture. Next, a partial polymer (acrylic polymer slurry) having a polymerization rate of about 10% by weight was obtained by performing partial photopolymerization by exposing the monomer mixture to ultraviolet rays in a nitrogen atmosphere. To 100 parts by weight of the acrylic polymer slurry thus obtained, 0.025 parts by weight of trimethylolpropane triacrylate (TMPTA) and 0.3 parts by silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) Then, these were mixed uniformly to prepare an adhesive composition (A).

(Manufacture of Adhesive Layer (A))
The said adhesive composition (A) was apply | coated on the peeling process surface of a release film so that the thickness after adhesive layer formation might be 100 micrometers, and the coating layer was formed. Next, another release film is coated on the surface of the coating layer such that the release-treated surface becomes the coating layer side. Thereafter, ultraviolet light was irradiated under the conditions of illuminance: 6.5 mW / cm ² , light amount: 2000 mJ / cm ² , and peak wavelength: 350 nm to harden the coating layer to form an adhesive layer (A). An adhesive sheet with a release film is provided on both sides of the adhesive layer (A) (no substrate type, the thickness of the adhesive layer: 100 μm). The refractive index (n _D ) of the D-line of the adhesive layer (A) measured by an Abbe refractometer at 23 ° C. was 1.48, and the gel fraction was 67%.

Comparative Example 2
(Preparation of Adhesive Composition (B))
In a monomer mixture containing 76 parts by weight of 2-ethylhexyl acrylate (2EHA), 18 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 16 parts by weight of 2-hydroxyethyl acrylate (HEA) In the formula, 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure184, having an absorption band at a wavelength of 200 to 370 nm, manufactured by BASF Corporation) as a photopolymerization initiator, and 0.050 parts by weight of 2,2-dimethoxy -1,2-Diphenylethane-1-one (trade name: Irgacure651, having an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF), 0.050 parts by weight, and then irradiating ultraviolet rays to the viscosity (measurement conditions: BH viscometer No .5 rotor, 10 rpm, measurement temperature 30 ° C.) to a prepolymer composition (polymerization rate: 9%) in which a part of the monomer components was partially polymerized until it reached 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 Shin-Etsu Chemical Co., Ltd.) were added to the prepolymer composition, and mixed to obtain Adhesive composition (b).

(Preparation of Adhesive Composition (B))
To the obtained adhesive composition (b) (100 parts by weight of a monomer component forming an acrylic polymer) was added 2,4-, which was dissolved in butyl acrylate so that the solid content became 15%. Bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-tri (trade name: Tinosorb S , The maximum absorption wavelength of the absorption spectrum: 346 nm, manufactured by BASF JAPAN) 0.8 parts by weight (weight of solid content), and bis (2,4,6-trimethylbenzyl) -phenylphosphine oxide ( Trade name: Irgacure 819, which has an absorption band at a wavelength of 200 to 450 nm, manufactured by BASF JAPAN Co., Ltd.) and 0.3 parts by weight is stirred to obtain an adhesive composition (B).

(Manufacture of Adhesive Layer (B))
The said adhesive composition (B) was apply | coated on the peeling process surface of a release film so that the thickness after an adhesive layer formation might be 150 micrometers, and the coating layer was formed. Next, another release film is coated on the surface of the coating layer such that the release-treated surface becomes the coating layer side. Thereafter, ultraviolet light was irradiated under the conditions of illuminance: 6.5 mW / cm ² , light amount: 2000 mJ / cm ² , and peak wavelength: 350 nm to harden the coating layer to form an adhesive layer (B). Adhesive sheets (without substrate type, thickness of the adhesive layer: 150 μm) are provided on both sides of the adhesive layer (B) with a release film. The refractive index (n _D ) of the D-line of the adhesive layer (B) measured by an Abbe refractometer at 23 ° C. was 1.49, and the gel fraction was 88%.

Comparative Example 3
(Preparation of Adhesive Composition (C))
Into a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube, and a nitrogen introduction tube, 95 parts by weight of butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), and azobisisobutyronitrile as a polymerization initiator were charged. After 0.2 parts by weight and 233 parts by weight of ethyl acetate, nitrogen gas was introduced, and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, the flask was heated to 60 ° C. and reacted for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1.1 million. To the acrylic polymer solution (with a solid content of 100 parts by weight), trimethylolpropane toluene diisocyanate (trade name: Coronate L, manufactured by Nippon Polyurethane Industry (stock)) as an isocyanate-based crosslinking agent was added 0.8 An adhesive composition (C: solution) was prepared by 0.1 part by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.).

(Manufacture of Adhesive Layer (C))
The above-mentioned adhesive composition (C: solution) was applied on the release-treated surface of the release film so that the thickness after drying became 23 μm, and the layer was dried at 100 ° C. for 3 minutes to remove the solvent to obtain an adhesive layer ( C). Then, it heated at 50 degreeC for 48 hours, and performed the crosslinking process. The other release film was coated on the exposed surface of the obtained adhesive layer (C) so that the release-treated surface became the exposed surface side described above, and an adhesive sheet provided with a release film on both surfaces of the adhesive layer (C) ( No substrate type, thickness of adhesive layer: 23 μm). The refractive index (n _D ) of the D-line of the adhesive layer (C) measured by an Abbe refractometer at 23 ° C. was 1.47, and the gel fraction was 82%.

Comparative Example 4
(Preparation of Adhesive Composition (D))
Into a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube, and a nitrogen introduction tube, 99 parts by weight of butyl acrylate (BA) and 4-hydroxybutyl acrylate were charged so that the solid content became 30% by weight. After 1 part by weight of ester (4HBA), 0.2 parts by weight of azobisisobutyronitrile as a polymerization initiator, and ethyl acetate as a polymerization solvent, nitrogen gas was introduced, and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, the flask was heated to 60 ° C. and reacted for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1.1 million. To this acrylic polymer solution (100 parts of solid content), 0.11 part of trimethylolpropane xylylene diisocyanate ("Takeneto D110N" manufactured by Mitsui Chemicals Co., Ltd.) as an isocyanate-based crosslinking agent was added. 0.1 parts of a silane coupling agent ("KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare an adhesive composition (D: solution).

(Manufacture of Adhesive Layer (D))
The above-mentioned adhesive composition (D: solution) was applied on the release-treated surface of the release film so that the thickness after drying became 20 μm, and the layer was dried at 120 ° C. for 3 minutes to remove the solvent to obtain an adhesive layer ( D). Then, it heated at 50 degreeC for 48 hours, and performed the crosslinking process. The other release film was coated on the exposed surface of the obtained adhesive layer (D) so that the release-treated surface became the exposed surface side described above, and an adhesive sheet provided with a release film on both surfaces of the adhesive layer (D) ( No substrate type, thickness of adhesive layer: 23 μm). The refractive index (n _D ) of the D-line of the adhesive layer (D) measured by an Abbe refractometer at 23 ° C. was 1.47, and the gel fraction was 75%.

Example 1
(Preparation of dispersions containing low refractive index particles)
Hollow nanometer silica particles (hollow particles, refractive index: 1.24, average primary particle size: 75 nm, trade name: Thrulya5320, manufactured by JGC Catalysts and Chemicals Co., Ltd.) for a dispersion medium (methyl ethyl ketone / methyl Isobutyl ketone = 9/1: volume ratio) was diluted to prepare a dispersion liquid having a particle concentration of 1.5% by weight as a dispersion liquid containing low refractive index particles.

(Manufacturing of adhesive layer with adjusted refractive index)
The release film on one side of the adhesive sheet obtained in Comparative Example 1 was peeled. The dispersion liquid was coated on the surface of the exposed adhesive layer (A) with a rod coater RDS No. 3 so that the thickness of the refractive index adjustment region became about 20 nm to 150 nm. Dry in a drying cabinet for 180 seconds. Next, a second release film was newly bonded to the surface of the adhesive layer (A) in which the hollow nano silica particles were dispersed, to obtain an adhesive sheet. In addition, with respect to the 2nd release film, the mold release film of the opposite side was made into the 1st release film.

Examples 2 to 8
In Example 1, the type of the adhesive layer and the type of the dispersion (the type of the low-refractive index particles, the average particle diameter, the type of the dispersion medium, and the particle concentration) were changed as shown in Table 1. In the same manner as in Example 1, an adhesive sheet having an adhesive layer with an adjusted refractive index was produced.
In addition, when the target thickness of the refractive index adjustment region after drying is about 150 to 300 nm, use a rod coater RDS No. 5 and the target thickness of the refractive index adjustment region after drying is 20 to In the case of about 150 nm, a rod coater RDS No. 3 is used.

(Evaluation)
Table 1 shows the results of the following evaluations of the adhesive layers (adhesive sheets) obtained in the examples and comparative examples.

＜ Measurement of average surface refractive index ＞
The average surface refractive index of the adhesive layer (refractive index adjustment region side: second surface) obtained in the examples was measured on a sodium D line (589 nm) using a spectroscopic ellipsometer (EC-400, manufactured by JA. Woolam). The refractive index. The release film on both sides was peeled from the adhesive sheets obtained in the examples and comparative examples, and the blackboard was attached to the surface (the first surface) where the dispersion liquid was not applied, and the surface on which the dispersion liquid was applied (the first surface) was measured. 2 faces). For the adhesive sheet of the comparative example, the average refractive index of the surface of the adhesive layer was measured in a state where the release sheets on both sides were peeled off and the blackboard was attached to one side. 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>
The cross section in the depth direction of the adhesive layer was adjusted and observed by TEM (Transmission Electron Microscopy). The thickness of the refractive index adjustment region was measured based on the obtained TEM image (direct magnification: 3000 to 30,000 times). The thickness of the refractive index adjustment region is the average value of the unevenness at the interface between the region where the particles are dispersed and the region where it is not dispersed in the adhesive layer. When it is difficult to determine the interface, the surface TEM image is processed by image The software (ImageJ) performs binary image processing, and the depth of the area where 90% (area) of particles exist.

<Total light transmittance and haze>
The second release film (the second surface side of the adhesive layer) was peeled from the adhesive sheet obtained in the example, and it was bonded to a glass slide (trade name: White Polishing No. 1, thickness: 0.8 to 1.0 mm, full light Transmittance: 92%, Haze: 0.2%, manufactured by Matsunami Glass Ind. Furthermore, the first release film on the other side was peeled off, and a test piece having an adhesive layer (the refractive index adjustment region is on the slide glass side) / layer structure of the slide glass was produced. On the other hand, with respect to the adhesive layer of the comparative example, the release film on one side was peeled off and bonded to the same glass slide as above, and then the release film on the other side was peeled off to produce an adhesive layer / glass slide. The test piece consisting of layers. The haze meter (device name: HM-150, manufactured by Murakami Color Research Institute, Ltd.) was used to measure the total light transmittance and haze value in the visible light region of the test piece.

＜ Adhesiveness ＞
From the adhesive sheets obtained in the examples and comparative examples, a sheet segment having a length of 100 mm and a width of 20 mm was cut. Next, the first release film (the side where the adhesive layer is not coated with the dispersion liquid) was peeled from the sheet section of the adhesive sheet obtained in the example, and then a PET (Polyethylene Terephthalate) film ( Trade name: Lumirror S-10, thickness: 25 μm, Toray (manufactured) is attached (substrate) to the adhesive layer. Then, the second release film was peeled off, and the test plate was pressure-bonded to a glass plate (trade name: soda-lime glass 500050, manufactured by Matsunami Glass Ind (stock)) under a pressure-bonding condition of 2 kg rolls and 1 round-trip as a test plate, and produced to include Sample of test board / adhesive layer (PET side on the first side) / PET film. On the other hand, for the sheet segment of the adhesive sheet obtained from the comparative example, after the release film on one side is peeled off, the same PET film as above is peeled off on the adhesive layer, and then the release film on the other side is peeled off and used. Samples were made on the same test plates as above. The obtained sample was subjected to an autoclave treatment (50 ° C, 0.5 MPa, 15 minutes), and then allowed to cool in an atmosphere of 23 ° C and 50% RH for 30 minutes. After cooling, a tensile tester (device name: Autograph AG-IS, manufactured by Shimadzu Corporation) was used in accordance with JIS Z0237 at a temperature of 23 ° C and 50% RH at a tensile speed of 300 mm / min. At an angle of 180 °, the adhesive sheet (adhesive layer / PET film) was peeled from the test plate, and the 180 ° peeling adhesive force (N / 20 mm) was measured.

＜ Measurement of surface reflectance ＞
The surface (second surface) on the side of the adhesive layer obtained in the example where the dispersion liquid was applied was used as the reflectance measurement surface. The first release film (the side where the adhesive layer was not coated with the dispersion) was peeled from the adhesive sheet obtained in the example, and a black acrylic resin plate (trade name "CLAREX", manufactured by Nitto Jushi Kogyo) was laminated, and then the first release film was peeled off. 2 A release film (the side on which the adhesive layer is coated with the dispersion liquid), and this peeled surface is used as a sample for surface reflectance measurement. 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 bonded to the same black acrylic resin plate as above, and then the release film on the other side was peeled off. This peeled surface was used as a sample for surface reflectance measurement. The surface reflectance (Y value) was measured with a reflective spectrophotometer (U4100, manufactured by Hitachi High-Technologies Corporation).

<Measurement of Internal Reflection Suppression (Improving Effect of Transmittance)>
After the second release film (the side on which the adhesive layer is coated with the dispersion liquid) is peeled off from the adhesive sheet obtained in the example, the second release film is adhered to the adhesive layer to form a triacetam cellulose film with a refractive index of 1.36. On the low-refractive-index layer side of the laminated film of the low-refractive-index layer, the low-refractive-index adjustment region of the adhesive layer is laminated so as to contact the low-refractive-index layer on the laminated film. Next, the first release film was peeled off, and a glass slide (trade name: Polishing No. 1, thickness: 0.8 to 1.0 mm, total light transmittance: 92%, haze: 0.2%, manufactured by Matsunami Glass Ind Co., Ltd.) ) Fit on the adhesive layer. In this manner, a test piece having a layer structure of a triethylammonium cellulose film / low-refractive index layer / adhesive layer (the second surface is the low-refractive index layer side) / glass slide was prepared. On the other hand, for the adhesive layer obtained in the comparative example, after the release film on one side was peeled off from the adhesive sheet, a triethylfluorene cellulose film / low refractive index layer / adhesive layer was produced in the same manner as above. / Slide is a test piece consisting of layers.

The internal reflection suppression ratio (the improvement effect of the transmittance) is determined by measuring the transmittance of the test piece produced above and calculating it based on the following formula. The "transmittance (%) in the absence of particles" in the following formula is the reflectance of the test piece of the comparative example. That is, the internal reflection suppression effect (transmittance improvement effect) is an index showing how much the internal reflectance can be reduced by having a refractive index adjustment layer.
Internal reflection suppression ratio (%) = "transmittance (%)"-"transmittance without particles (%)"

[Table 1]

The contents shown in Table 1 are as follows:
(X1) hollow nanometer silica particles: refractive index 1.24 (trade name: Thrulya5320, particle size 75 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.);
(X2) hollow polymer fine particles: refractive index 1.32 (trade name: TechpolymerNH, model XX-255AA, particle diameter 80 nm, manufactured by Sekisui Plastics Co., Ltd.);
(X3) hollow polymer fine particles: refractive index 1.33 (trade name: TechpolymerNH, model XX-260AA, particle diameter 60 nm, manufactured by Sekisui Plastics Co., Ltd.);
(Y1) MgF ₂ : 1.38, average primary particle size: 40 nm, manufactured by CIK NanoTek (stock);
(Y2) Na ₃ AlF ₆ : 1.34, average primary particle size: 50 nm, manufactured by CIK NanoTek (stock);
MEK / MIBK: methyl ethyl ketone / methyl isobutyl ketone = 9/1 (volume ratio);
Ethanol / MIBK: ethanol / methyl isobutyl ketone = 9/1 (volume ratio);
IPA: isopropanol.

1‧‧‧adhesive layer

1'‧‧‧ foundation adhesive layer

1a‧‧‧The whole substrate (matrix) of the adhesive layer

2‧‧‧ Low refractive index materials

3a‧‧‧ support

3b‧‧‧ support

4‧‧‧ optical film

5‧‧‧Low-refractive optical components

10‧‧‧dispersion

A‧‧‧ Optical film with adhesive layer

B‧‧‧ Optical Laminate

f1‧‧‧The first side of the adhesive layer

f1'‧‧‧ the first side of the base adhesive layer

f2‧‧‧‧‧‧‧ 2nd side of the adhesive layer

f2'‧‧‧The second side of the base adhesive layer

T‧‧‧Thickness of refractive index adjustment region

S‧‧‧ support

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

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

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

Fig. 4 is a sectional view showing an embodiment of the adhesive sheet of the present invention.

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

FIG. 6 is a cross-sectional view showing an embodiment of an optical multilayer body according to the present invention.

Claims (21)

An adhesive layer characterized in that it has a first surface and a second surface opposite to the first surface, and The above-mentioned adhesive layer forms an entire substrate of the adhesive layer by using the adhesive composition containing the base polymer, The first surface has a first refractive index based on the adhesive composition, and on the other hand, the second refractive index of the second surface is lower than the first refractive index of the first surface. For example, the adhesive layer of claim 1 or 2, wherein the difference between the first refractive index of the first surface and the second refractive index of the second surface is 0.02 to 0.45. The adhesive layer according to any one of claims 1 to 3, wherein the second refractive index of the second surface is 1.45 or less. The adhesive layer according to any one of claims 1 to 3, wherein in the adhesive layer, a low refractive index material having a refractive index lower than a refractive index of the base polymer is dispersed on the second surface side. For example, in the adhesive layer of claim 4, the thickness of the region in which the low refractive index material is dispersed is 600 nm or less in the thickness direction from the second surface side of the adhesive layer. For example, the adhesive layer of claim 4 or 5, wherein the refractive index of the base polymer is 1.40 to 1.55, and the refractive index of the low refractive material is 1.10 to 1.45. The adhesive layer according to any one of claims 4 to 6, wherein the difference between the refractive index of the base polymer and the refractive index of the low-refractive material is 0.07 to 0.45. The adhesive layer according to any one of claims 4 to 7, wherein the low-refractive material is particles having an average particle diameter of 10 nm to 150 nm. The adhesive layer according to any one of claims 4 to 8, wherein the low-refractive material is at least one inorganic particle selected from the group consisting of MgF ₂ , CaF _2, and Na ₃ AlF ₆ , and is selected from a porous material. At least one particle in a group consisting of silica particles, hollow nano silica particles, and hollow polymer particles. For example, the adhesive layer of any one of claims 1 to 9 has a total light transmittance of 85% or more. The adhesive layer according to any one of claims 1 to 10, wherein the reflectance of the second surface is 0.5 to 3.5%. For example, the adhesive layer of any one of claims 1 to 11, wherein the difference between the reflectance of the first surface and the second surface is 0.1 to 3.5%. The gel fraction of the adhesive layer according to any one of claims 1 to 12, has a gel fraction of 30 to 95% by weight. For example, the adhesive layer of any one of claims 1 to 13 has a storage elastic modulus G ′ at 25 ° C. of 0.05 to 0.50 MPa. For example, if the adhesive layer of any one of claims 1 to 14, the peak value of tan δ at the time of dynamic viscoelasticity measurement at 1 Hz is -5 to -50 ° C. A method for manufacturing an adhesive layer, which is characterized in that it is the method for manufacturing an adhesive layer according to any one of claims 1 to 15, and includes: Step (1), which uses a base polymer-containing adhesive composition to form a base adhesive layer on a support; Step (2), which is preparing a dispersion liquid in which a low refractive index material having a refractive index lower than the refractive index of the base polymer is dispersed; Step (3), which is to apply the dispersion to the second side opposite to the first side of the support side of the base adhesive layer, so that the low refractive index material contained in the dispersion adheres to the base. The second layer of the agent layer penetrates through the thickness direction; and Step (4) is to dry the adhesive layer after the low refractive index material is impregnated. An adhesive sheet is characterized in that it has an adhesive layer according to any one of claims 1 to 15 and has a support on one or both sides of the adhesive layer. An optical film with an adhesive layer is characterized in that it has an optical film and an adhesive layer provided on one or both sides of the optical film, and The single-sided or double-sided adhesive layer is the adhesive layer according to any one of claims 1 to 15, and the first surface side of the adhesive layer is provided on the optical film. For example, the optical film with an adhesive layer of claim 18, wherein the optical film is a polarizing film. An optical laminated body characterized in that it has an optical film with an adhesive layer as claimed in claim 18 or 19 and a low-refractive index optical member attached to the adhesive layer of the optical film with the adhesive layer. An image display device, characterized in that it has an adhesive layer as in any one of claims 1 to 15, an optical film with an adhesive layer as in claim 18 or 19, or an optical build-up as in claim 19 body.