JP2021160242A - Optical laminate - Google Patents

Abstract

To reduce the number of processes or necessary components in a manufacturing process of a self-luminous type display device such as a mini/micro LED display device with improved antireflection function and/or antiglare function and contrast.SOLUTION: An optical laminate 10 includes a substrate 1 and an adhesive layer 2 containing a coloring agent. The substrate 1 is subject to an antireflection treatment and/or an antiglare treatment 3 on one side 1a thereof. An antiglare layer is preferably formed by the antireflection treatment and/or the antiglare treatment 3. In the optical laminate 10, the adhesive layer 2 is laminated on a face 1b of the substrate 1 without the antireflection treatment and/or the antiglare treatment.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical laminate suitable for sealing a light emitting element of a self-luminous display device such as a mini / micro LED.

In recent years, as a next-generation display device, a self-luminous display device represented by a mini / micro LED display device (Mini / Micro Light Emitting Diode Display) has been devised. As a basic configuration of a mini / micro LED display device, a substrate in which a large number of minute LED light emitting elements (LED chips) are arranged at high density is used as a display panel, and the LED chips are sealed with a sealing material. A cover member such as a resin film or a glass plate is laminated on the outermost layer.

There are several self-luminous display devices such as mini / micro LED display devices, such as a white backlight system, a white emission color filter system, and an RGB system. In the white emission color filter system and the RGB system, the display panel is used. A black encapsulant may be used to prevent reflection of metal wiring or metal oxides such as ITO arranged on the substrate (see, for example, Patent Documents 1 to 3). Above all, in the RGB type mini / micro LED display device in which the LED chips are arranged, the black encapsulant can contribute to the prevention of RGB color mixing and the improvement of contrast.

JP-A-2019-204905 JP-A-2017-203810 Special Table 2018-523854

As the black encapsulant, a liquid curable resin or an adhesive containing a black colorant (dye or pigment) is used. When a liquid curable resin containing a black colorant is used, there is a problem that the blackness becomes uneven due to the uneven thickness. In addition, pigments are often selected because they are superior in heat resistance and weather resistance to dyes. However, when a liquid curable resin in which pigments are dispersed is used, in addition to the above-mentioned thickness unevenness, liquid curability Problems such as uneven filling during resin filling and uneven dispersion of pigments during flow occur. In addition, since the surface of the liquid curable resin cured after sealing has no adhesive force, it is necessary to laminate the cover members using an adhesive or the like, which also causes a problem that additional man-hours and members are required. there were.

The present invention has been conceived under the above circumstances, and an object of the present invention is to provide an antireflection function and / or an antiglare function, a mini / micro LED display device having improved contrast, and the like. This is to reduce the number of processes and necessary members in the manufacturing process of the light emitting display device.

As a result of diligent studies to achieve the above object, the present inventors self-luminous an optical laminate in which a base material having an antireflection treatment and / or an antiglare treatment on one side and an adhesive layer containing a colorant is laminated. By using it in the manufacture of type display devices, it is possible to reduce the number of processes and required members, and it is possible to efficiently manufacture self-luminous display devices with improved antireflection function and / or anti-glare function and contrast. I found it. The present invention has been completed based on these findings.

That is, the first aspect of the present invention is an optical laminate containing a base material and an adhesive layer containing a colorant, and one side of the base material is antireflection-treated and / or antiglare-treated. Provided is an optical laminate in which the pressure-sensitive adhesive layer is laminated on a surface of the base material that has not been subjected to the antireflection treatment and / or the antiglare treatment. By using the optical laminate on the first side surface of the present invention for manufacturing a self-luminous display device, the pressure-sensitive adhesive layer serves as a sealing material for sealing the light-emitting elements arranged on the display panel, and the base material becomes a base material. Since it is the cover member of the outermost layer, it is not necessary to separately stack the cover member after sealing, the number of steps and the required member can be reduced, and the manufacturing efficiency is improved.

Further, in the configuration in which the pressure-sensitive adhesive layer contains a colorant, when the light emitting element is sealed with the pressure-sensitive adhesive layer in the manufacture of a self-luminous display device, the above-mentioned thickness unevenness, filling unevenness, pigment dispersion unevenness, etc. It is preferable because unevenness of blackness due to the above is less likely to occur, and further, it is possible to prevent reflection of metal wiring and the like, prevent RGB color mixing, and improve contrast.
Furthermore, the configuration in which one side of the base material is anti-reflection treated and / or anti-glare treated prevents deterioration of visibility due to reflection of external light and reflection of an image, and adjusts the appearance such as glossiness. Preferred from the point of view.

In the optical laminate of the first aspect of the present invention, the pressure-sensitive adhesive layer is formed of a photocurable pressure-sensitive adhesive composition containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant. It is preferably a pressure-sensitive adhesive layer. The colorant preferably has an average transmittance at a wavelength of 330 to 400 nm higher than an average transmittance at a wavelength of 400 to 700 nm. The photopolymerization initiator preferably has at least one absorption maximum in the wavelength range of 330 to 400 nm. The optical laminate preferably has a maximum transmittance at 350 nm to 450 nm. The total light transmittance of the pressure-sensitive adhesive layer is preferably 80% or less. The thickness of the pressure-sensitive adhesive layer is preferably 10 to 500 μm. These configurations are preferable in that the pressure-sensitive adhesive layer can impart photocurability by ultraviolet irradiation while having sufficient light-shielding property in the visible light region.

In the optical laminate of the first side surface of the present invention, the polymer is preferably an acrylic polymer. The glass transition temperature of the polymer is preferably 0 ° C. or lower. The shear storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 85 ° C. is preferably 3 to 300 kPa. In these configurations, when the optical laminate on the first side surface of the present invention is used in the manufacture of a self-luminous display device, the pressure-sensitive adhesive layer is filled in the steps of the light emitting elements arranged on the display panel without gaps. , It is preferable in that it is excellent in step absorption.

In the optical laminate of the first aspect of the present invention, the photocurable pressure-sensitive adhesive composition preferably further contains a cross-linking agent capable of cross-linking with the polymer. The shear storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25 ° C. is preferably 10 to 1000 kPa. These configurations are preferable in that the processability and adhesive reliability of the pressure-sensitive adhesive layer can be improved.

In the optical laminate on the first side surface of the present invention, the antireflection treatment and / or the antiglare treatment is preferably an antiglare layer provided on one side of the base material. The anti-glare layer is formed by using an anti-glare layer forming material containing a resin, particles and a thixotropy-imparting agent, and the anti-glare layer is formed on the surface of the anti-glare layer by aggregating the particles and the thixotropy-imparting agent. It is preferable to have an agglomerated portion that forms a convex portion. In the convex portion on the surface of the anti-glare layer, the average inclination angle θa (°) is preferably in the range of 0.1 to 5.0. These configurations impart an antireflection function and / or an antiglare treatment to the surface of the optical laminate on the first side surface of the present invention, and prevent deterioration of visibility due to reflection of external light, reflection of an image, or the like. Alternatively, it is preferable from the viewpoint of adjusting the appearance such as glossiness.

In the optical laminate of the first side surface of the present invention, a surface protective film may be further laminated on the antireflection treatment and / or antiglare treatment surface of the base material. Such a configuration is suitable for preventing the adhesion of scratches and stains during the manufacture, transportation, and shipment of the optical laminate and the optical products containing the same.

The second side surface of the present invention is a self-luminous display device including a display panel in which a plurality of light emitting elements are arranged on one side of a substrate and an optical laminate of the first side surface of the present invention. Provided is a self-luminous display device in which a surface on which light emitting elements of a display panel are arranged and an adhesive layer of the optical laminate are laminated. In the self-luminous display device on the second side surface of the present invention, the display panel may be an LED panel in which a plurality of LED chips are arranged on one side of a substrate. In such a configuration, the self-luminous display device on the second side of the present invention can be visually recognized by preventing reflection of metal wiring on the substrate, preventing RGB color mixing, improving contrast, reflecting external light, reflecting an image, and the like. It is preferable in that it can prevent deterioration of the property or adjust the appearance such as glossiness.

By using the optical laminate of the present invention in the manufacture of a self-luminous display device, it is possible to reduce the number of steps and necessary members, and the self-luminous type with improved antireflection function and / or antiglare function and contrast. The display device can be manufactured efficiently.

FIG. 1 is a schematic view (cross-sectional view) showing an embodiment of the optical laminate of the present invention. FIG. 2 is a schematic view (cross-sectional view) showing another embodiment of the optical laminate of the present invention. FIG. 3 is a schematic view (cross-sectional view) showing an embodiment of the self-luminous display device (mini / micro LED display device) of the present invention. FIG. 4 is a schematic view (cross-sectional view) showing another embodiment of the self-luminous display device (mini / micro LED display device) of the present invention.

The optical laminate on the first side surface of the present invention is an optical laminate containing a base material and an adhesive layer containing a colorant, and one side of the base material is subjected to antireflection treatment and / or antiglare treatment. The pressure-sensitive adhesive layer is laminated on the surface of the base material that has not been subjected to the antireflection treatment and / or the antiglare treatment.

"Optical" in the optical laminate on the first side surface of the present invention means that it is used for optical purposes, and more specifically, it is used for manufacturing a product (optical product) using an optical member or the like. Means to be. Examples of optical products include an image display device, an input device such as a touch panel, and a self-luminous display device such as a mini / micro LED display device and an organic EL (electroluminescence) display device is preferable, and a mini is particularly preferable. / Can be suitably used for manufacturing a micro LED display device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto and is merely an example.
FIG. 1 is a schematic view (cross-sectional view) showing an embodiment of an optical laminate on the first side surface of the present invention.

In the present embodiment, the optical laminate 10 includes a base material 1 and a pressure-sensitive adhesive layer 2 containing a colorant. The base material 1 is subjected to antireflection treatment and / or antiglare treatment 3 on one side 1a thereof. The pressure-sensitive adhesive layer 2 is laminated on the surface 1b on the side of the base material 1 that has not been subjected to the antireflection treatment and / or the antiglare treatment.

<Base material>
In the present embodiment, the base material 1 is not particularly limited, and examples thereof include glass and a transparent plastic film base material. The transparent plastic film base material is not particularly limited, but is preferably one having excellent visible light transmittance (preferably 90% or more) and excellent transparency (preferably one having a haze value of 5% or less). For example, the transparent plastic film base material described in JP-A-2008-90263 can be mentioned. As the transparent plastic film base material, one having less birefringence optically is preferably used. In the present embodiment, the base material 1 can be used, for example, as a cover member of a self-luminous display device. In this case, the transparent plastic film base material includes triacetyl cellulose (TAC), polycarbonate, or acrylic. A film formed of a based polymer, a polyolefin having a cyclic or norbornene structure, or the like is preferable. Further, in the present embodiment, the base material 1 may be the cover member itself. With such a configuration, it is possible to reduce the steps of separately laminating the cover members in the manufacture of the self-luminous display device, so that the number of steps and the required members can be reduced, and the production efficiency can be improved. Further, with such a configuration, the cover member can be made thinner. When the base material 1 is a cover member, the antireflection-treated and / or anti-glare-treated surface 1a becomes the outermost surface of the self-luminous display device, and is visually recognized by reflection of external light or reflection of an image. It plays a role of preventing deterioration of the property and adjusting the appearance such as glossiness.

In the present embodiment, the thickness of the base material 1 is not particularly limited, but is preferably in the range of 10 to 500 μm, more preferably 20 in consideration of workability such as strength and handleability and thin layer property. It is in the range of ~ 300 μm, and optimally in the range of 30 to 200 μm. The refractive index of the base material 1 is not particularly limited, but is, for example, in the range of 1.30 to 1.80, preferably in the range of 1.40 to 1.70. The visible light transmittance of the base material 1 is not particularly limited, but is, for example, 85 to 100%, and may be 88% or more, 90% or more, or 92% or more.

In the present embodiment, as the antireflection treatment applied to one side 1a of the base material 1, a known antireflection treatment can be used without particular limitation, and examples thereof include an antireflection (AR) treatment.

As the antireflection (AR) treatment, a known AR treatment can be applied without particular limitation. Specifically, an optical thin film having a thickness and a refractive index strictly controlled on one side 1a of the base material 1 or the above. This can be carried out by forming an antireflection layer (AR layer) in which two or more optical thin films are laminated. The AR layer exhibits an antireflection function by canceling each other's reversed phases of incident light and reflected light by utilizing the interference effect of light. The wavelength region of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength region having particularly high visual sensitivity is in the range of 450 to 650 nm, and the reflectance of 550 nm, which is the central wavelength thereof, is minimized. It is preferable to design the AR layer as described above.

Examples of the AR layer include a multi-layer antireflection layer having a structure in which two or five optical thin layers (thin films whose thickness and refractive index are strictly controlled) are laminated, and components having different refractive indexes are specified. By forming multiple layers with the same thickness as the above, the degree of freedom in the optical design of the AR layer is increased, the antireflection effect can be further improved, and the spectral reflection characteristics can be made uniform (flat) in the visible light region. become. Since high thickness accuracy is required for the optical thin film, the formation of each layer is generally carried out by a dry method such as vacuum vapor deposition, sputtering, or CVD.

As the anti-glare (AG) treatment, a known AG treatment can be applied without particular limitation, and can be carried out, for example, by forming an anti-glare layer on one side 1a of the base material 1. FIG. 2 is a schematic view (cross-sectional view) showing another embodiment of the optical laminate of the first side surface of the present invention. In the optical laminate 11 of the present embodiment, the anti-glare layer 3a is formed on one side 1a of the base material 1. As the anti-glare layer 3a, known ones can be adopted without limitation, and generally, it is formed as a layer in which inorganic or organic particles are dispersed as an anti-glare agent in a resin.

In the present embodiment, the anti-glare layer 3a is formed by using an anti-glare layer forming material containing a resin, particles and a thixotropy-imparting agent, and the surface of the anti-glare layer 3a is formed by agglutination of the particles and the thixotropy-imparting agent. A convex portion is formed on the surface. Due to this configuration, the anti-glare layer 3a has excellent display characteristics that achieve both anti-glare properties and prevention of white blur, and despite the fact that the anti-glare layer is formed by utilizing the aggregation of particles, the appearance is defective. It is possible to prevent the generation of protrusions on the surface of the anti-glare layer and improve the yield of the product.

Examples of the resin include thermosetting resins and ionizing radiation curable resins that are cured by ultraviolet rays or light. As the resin, a commercially available thermosetting resin, an ultraviolet curable resin, or the like can also be used.

As the heat-curable resin or the ultraviolet-curable resin, for example, a curable compound having at least one of an acrylate group and a methacrylate group that is cured by heat, light (ultraviolet rays, etc.), an electron beam, or the like can be used. Silicone resin, polyester resin, polyether resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiol polyene resin, oligomers such as methacrylate and prepolymers of polyfunctional compounds such as polyhydric alcohol can give. One of these may be used alone, or two or more thereof may be used in combination.

For the resin, for example, a reactive diluent having at least one group of an acrylate group and a methacrylate group can also be used. As the reactive diluent, for example, the reactive diluent described in JP-A-2008-88309 can be used, and includes, for example, monofunctional acrylate, monofunctional methacrylate, polyfunctional acrylate, polyfunctional methacrylate and the like. As the reactive diluent, trifunctional or higher functional acrylates and trifunctional or higher functional methacrylates are preferable. This is because the hardness of the anti-glare layer 3a can be made excellent. Examples of the reactive diluent include butanediol glycerin ether diacrylate, isocyanuric acid acrylate, and isocyanuric acid methacrylate. One of these may be used alone, or two or more thereof may be used in combination.

The main function of the particles for forming the anti-glare layer 3a is to shape the surface of the formed anti-glare layer 3a into an uneven shape to impart anti-glare properties, and to control the haze value of the anti-glare layer 3a. The haze value of the anti-glare layer 3a can be designed by controlling the difference in refractive index between the particles and the resin. Examples of the particles include inorganic particles and organic particles. The inorganic particles are not particularly limited, and for example, silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, calcium sulfate particles and the like. Can be given. The organic particles are not particularly limited, and for example, polymethylmethacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, and polyolefin. Examples thereof include resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyfluorinated ethylene resin powder. One type of these inorganic particles and organic particles may be used alone, or two or more types may be used in combination.

The weight average particle size (D) of the particles is preferably in the range of 2.5 to 10 μm. By setting the weight average particle size of the particles in the above range, for example, more excellent anti-glare properties and white blurring can be prevented. The weight average particle size of the particles is more preferably in the range of 3 to 7 μm. The weight average particle size of the particles can be measured by, for example, the Coulter counting method. For example, using a particle size distribution measuring device (trade name: Coulter Multisizer, manufactured by Beckman Coulter) using the pore electrical resistance method, an electrolytic solution corresponding to the volume of the particles when the particles pass through the pores. By measuring the electrical resistance, the number and volume of the particles are measured, and the weight average particle size is calculated.

The shape of the particles is not particularly limited, and may be, for example, a bead-shaped substantially spherical shape or an irregular shape such as powder, but a substantially spherical shape is preferable, and an aspect ratio is more preferable. It is a substantially spherical particle having a ratio of 1.5 or less, and most preferably a spherical particle.

The proportion of the particles in the anti-glare layer 3a is preferably in the range of 0.2 to 12 parts by weight, more preferably in the range of 0.5 to 12 parts by weight, still more preferably 1 with respect to 100 parts by weight of the resin. It is in the range of ~ 7 parts by weight. Within the above range, for example, more excellent anti-glare property and white blurring can be prevented.

Examples of the thixotropy-imparting agent for forming the anti-glare layer 3a include organic clay, polyolefin oxide, modified urea and the like.

The organic clay is preferably an organically treated clay in order to improve the affinity with the resin. Examples of the organic clay include layered organic clay. The organic clay may be prepared in-house or a commercially available product may be used. Examples of the commercially available products include Lucentite SAN, Lucentite STN, Lucentite SEN, Lucentite SPN, Somasif ME-100, Somasif MAE, Somasif MTE, Somasif MEE, and Somasif MPE (trade names, all of which are CO-OP CHEMICAL CO., LTD. ); Esben, Esben C, Esben E, Esben W, Esben P, Esben WX, Esben N-400, Esben NX, Esben NX80, Esben NO12S, Esben NEZ, Esben NO12, Esben NE, Esben NZ, Esben NZ70, Organite, Organite D, Organite T (trade name, all manufactured by Hojun Co., Ltd.); Kunipia F, Kunipia G, Kunipia G4 (trade name, all manufactured by Kunimine Kogyo Co., Ltd.); Chixogel VZ, Clayton HT , Clayton 40 (trade name, all manufactured by Rockwood Additives) and the like.

The polyolefin oxide may be prepared in-house or a commercially available product may be used. Examples of the commercially available product include Disparon 4200-20 (trade name, manufactured by Kusumoto Kasei Co., Ltd.), Fronon SA300 (trade name, manufactured by Kyoeisha Chemical Co., Ltd.) and the like.

The modified urea is a reaction product of an isocyanate monomer or an adduct thereof and an organic amine. The modified urea may be prepared in-house or a commercially available product may be used. Examples of the commercially available product include BYK410 (manufactured by Big Chemie).

The thixotropy-imparting agent may be used alone or in combination of two or more.

In the optical laminate 11 of the present embodiment, the height of the convex portion from the roughness average line of the anti-glare layer 3a is preferably less than 0.4 times the thickness of the anti-glare layer 3a. More preferably, it is in the range of 0.01 times or more and less than 0.4 times, and further preferably, it is in the range of 0.01 times or more and less than 0.3 times. Within this range, it is possible to suitably prevent the formation of protrusions, which are defects in appearance, on the convex portion. The anti-glare layer 3a of the present embodiment has a convex portion having such a height, so that appearance defects can be less likely to occur. Here, the height from the average line can be measured by, for example, the method described in JP-A-2017-138620.

The ratio of the thixotropy-imparting agent in the anti-glare layer 3a is preferably in the range of 0.1 to 5 parts by weight, more preferably in the range of 0.2 to 4 parts by weight, based on 100 parts by weight of the resin.

The thickness (d) of the anti-glare layer 3a is not particularly limited, but is preferably in the range of 3 to 12 μm. By setting the thickness (d) of the anti-glare layer 3a within the above range, for example, the occurrence of curl of the optical laminate 11 can be prevented, and the problem of reduced productivity such as poor transportability can be avoided. When the thickness (d) is in the range, the weight average particle size (D) of the particles is preferably in the range of 2.5 to 10 μm as described above. When the thickness (d) of the anti-glare layer 3a and the weight average particle size (D) of the particles are the combination described above, the anti-glare property can be further improved. The thickness (d) of the anti-glare layer 3a is more preferably in the range of 3 to 8 μm.

The relationship between the thickness (d) of the anti-glare layer 3a and the weight average particle size (D) of the particles is preferably in the range of 0.3 ≦ D / d ≦ 0.9. By having such a relationship, it is possible to obtain an anti-glare layer which is more excellent in anti-glare property, can prevent white blurring, and has no appearance defect.

In the optical laminate 11 of the present embodiment, as described above, the anti-glare layer 3a forms a convex portion on the surface of the anti-glare layer 3a by aggregating the particles and the thixotropy-imparting agent. In the agglomerated portion forming the convex portion, a plurality of the particles are present in a state of being gathered in the plane direction of the anti-glare layer 3a. As a result, the convex portion has a gentle shape. By having the convex portion having such a shape, the anti-glare layer 3a of the present embodiment can maintain anti-glare properties, prevent white blurring, and further reduce appearance defects. can.

The surface shape of the anti-glare layer 3a can be arbitrarily designed by controlling the aggregated state of the particles contained in the anti-glare layer forming material. The agglomerated state of the particles can be controlled by, for example, the material of the particles (for example, the chemically modified state of the particle surface, the affinity for a solvent or a resin, etc.), the type of the resin (binder) or the solvent, the combination, and the like. Here, in the present embodiment, the aggregated state of the particles can be controlled by the thixotropy-imparting agent contained in the antiglare layer forming material. As a result, in the present embodiment, the agglomerated state of the particles can be made as described above, and the convex portion can be made into a gentle shape.

In the optical laminate 11 of the present embodiment, when the base material 1 is formed of a resin or the like, it is preferable to have a permeation layer at the interface between the base material 1 and the anti-glare layer 3a. The permeation layer is formed by permeating the resin component contained in the material for forming the antiglare layer 3a into the base material 1. When the permeation layer is formed, the adhesion between the base material 1 and the anti-glare layer 3a can be improved, which is preferable. The permeation layer preferably has a thickness in the range of 0.2 to 3 μm, more preferably in the range of 0.5 to 2 μm. For example, when the base material 1 is triacetyl cellulose and the resin contained in the anti-glare layer 3a is an acrylic resin, the permeation layer can be formed. The permeation layer can be confirmed, for example, by observing the cross section of the optical laminate 11 with a transmission electron microscope (TEM), and the thickness can be measured.

In the present embodiment, even when applied to the optical laminate 11 having such a penetrating layer, a desired smooth surface uneven shape having both anti-glare property and prevention of white blur can be easily formed. Can be done. It is preferable that the permeation layer is formed thicker as the base material 1 has poor adhesion to the anti-glare layer 3a in order to improve the adhesion.

In the present embodiment, in the anti-glare layer 3a, it is preferable that the maximum diameter is 200 μm or more and the number of appearance defects is one or less per 1 ^{m 2 of the anti-glare layer 3a.} More preferably, there is no such appearance defect.

In the present embodiment, the base material 1 on which the anti-glare layer 3a is formed preferably has a haze value in the range of 0 to 10%. The haze value is a haze value (cloudiness) according to JIS K 7136 (2000 version). The haze value is more preferably in the range of 0 to 5%, and even more preferably in the range of 0 to 3%. In order to set the haze value in the above range, it is preferable to select the particles and the resin so that the difference in refractive index between the particles and the resin is in the range of 0.001 to 0.02. When the haze value is in the above range, a clear image can be obtained and the contrast in a dark place can be improved.

In the present embodiment, the average inclination angle θa (°) is preferably in the range of 0.1 to 5.0, preferably in the range of 0.3 to 4.5 in the uneven shape of the surface of the anti-glare layer 3a. It is more preferably in the range of 1.0 to 4.0, particularly preferably 1.6 to 4.0. Here, the average inclination angle θa is a value defined by the following mathematical formula (1). The average inclination angle θa is, for example, a value measured by the method described in JP-A-2017-138620.
Average inclination angle θa = tan-1Δa (1)

In the above formula (1), Δa is the peak and valley of the adjacent peaks in the reference length L of the roughness curve defined in JIS B 0601 (1994 version), as shown in the following formula (2). It is a value obtained by dividing the total (h1 + h2 + h3 ... + Hn) of the difference (height h) from the lowest point by the reference length L. The roughness curve is a curve obtained by removing a surface waviness component longer than a predetermined wavelength from a cross-sectional curve with a phase difference compensation type high frequency filter. Further, the cross-sectional curve is a contour that appears at the cut end when the target surface is cut on a plane perpendicular to the target surface.
Δa = (h1 + h2 + h3 ... + hn) / L (2)

When θa is in the above range, the anti-glare property is more excellent and white blurring can be prevented.

In forming the anti-glare layer 3a, it is preferable that the prepared anti-glare layer forming material (coating liquid) exhibits thixotropic properties, and the Ti value defined below is in the range of 1.3 to 3.5. It is preferably in the range of 1.3 to 2.8.
Ti value = β1 / β2
Here, β1 is a viscosity measured under the condition of a shear rate of 20 (1 / s) using a HAAKE Leostress 6000, and β2 is a viscosity of 200 (1 / s) using a HAAKE Leostress 6000. Viscosity measured under conditions.

If the Ti value is less than 1.3, appearance defects are likely to occur, and the characteristics regarding anti-glare property and white blur are deteriorated. Further, when the Ti value exceeds 3.5, the particles are less likely to aggregate and are likely to be in a dispersed state.

The method for producing the anti-glare layer 3a of the present embodiment is not particularly limited and may be produced by any method. For example, the anti-glare layer forming material (coating) containing the resin, the particles, the thixotropy-imparting agent and the solvent. Liquid) is prepared, the anti-glare layer forming material (coating liquid) is applied to one side 1a of the base material 1 to form a coating film, and the coating film is cured to form an anti-glare layer 3a. , Can be manufactured. In the present embodiment, a transfer method using a mold, a method of imparting an uneven shape by an appropriate method such as sandblasting or embossing roll, or the like can also be used.

The solvent is not particularly limited, and various solvents can be used, and one type may be used alone or two or more types may be used in combination. There are optimum solvent types and solvent ratios depending on the composition of the resin, the types of the particles and the thixotropy-imparting agent, the content, and the like. The solvent is not particularly limited, but for example, alcohols such as methanol, ethanol, isopropyl alcohol, butanol and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclopentanone; methyl acetate and ethyl acetate. , Esters such as butyl acetate; ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; cellosolves such as ethyl cellosolve and butyl cellosolve; aliphatic hydrocarbons such as hexane, heptane and octane. Kind: Aromatic hydrocarbons such as benzene, toluene, xylene and the like.

When, for example, triacetyl cellulose (TAC) is used as the base material 1 to form the permeation layer, a good solvent for TAC can be preferably used. Examples of the solvent include ethyl acetate, methyl ethyl ketone, cyclopentanone and the like.

Further, by appropriately selecting the solvent, the thixotropy of the thixotropy-imparting agent can be satisfactorily exhibited in the antiglare layer forming material (coating liquid). For example, when organic clay is used, toluene and xylene can be preferably used alone or in combination. For example, when polyolefin oxide is used, methyl ethyl ketone, ethyl acetate, and propylene glycol monomethyl ether are preferably used alone. It can be used or used in combination. For example, when modified urea is used, butyl acetate and methyl isobutyl ketone can be preferably used alone or in combination.

Various leveling agents can be added to the anti-glare layer forming material. As the leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used for the purpose of preventing uneven coating (uniformizing the coated surface). In the present embodiment, depending on the case where the surface of the anti-glare layer 3a is required to have antifouling property, or the case where an antireflection layer (low refractive index layer) or a layer containing an interlayer filler is formed on the anti-glare layer 3a. Therefore, the leveling agent can be appropriately selected. In the present embodiment, for example, by incorporating the thixotropy-imparting agent, the thixotropy can be exhibited in the coating liquid, so that uneven coating is less likely to occur. Therefore, the present embodiment has an advantage that, for example, the options of the leveling agent can be expanded.

The blending amount of the leveling agent is, for example, 5 parts by weight or less, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the resin.

Pigments, fillers, dispersants, plasticizers, ultraviolet absorbers, surfactants, antifouling agents, antioxidants and the like are added to the anti-glare layer forming material, if necessary, as long as the performance is not impaired. You may. One type of these additives may be used alone, or two or more types may be used in combination.

As the anti-glare layer forming material, for example, a conventionally known photopolymerization initiator as described in JP-A-2008-88309 can be used.

Examples of the method of applying the anti-glare layer forming material on one side 1a of the base material 1 include a fanten coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, and a bar coating method. Etc. can be used.

The anti-glare layer forming material is applied to form a coating film on the base material 1, and the coating film is cured. It is preferable to dry the coating film prior to the curing. The drying may be, for example, natural drying, air drying by blowing wind, heat drying, or a method in which these are combined.

The means for curing the coating film of the anti-glare layer forming material is not particularly limited, but ultraviolet curing is preferable. The irradiation amount of the energy radiation source is preferably ^{50 to 500 mJ / cm 2} as the integrated exposure amount at the ultraviolet wavelength of 365 nm. When the irradiation amount is 50 mJ / cm ² or more, the curing becomes more sufficient, and the hardness of the formed anti-glare layer becomes more sufficient. Further, if it is 500 mJ / cm ² or less, coloring of the formed anti-glare layer can be prevented.

As described above, the anti-glare layer 3a can be formed on one side 1a of the base material 1. The anti-glare layer 3a may be formed by a manufacturing method other than the above-mentioned method. The hardness of the anti-glare layer 3a of the present embodiment is affected by the thickness of the layer in terms of pencil hardness, but it is preferably 2H or more.

In the present embodiment, the anti-glare layer 3a may have a multi-layer structure in which two or more layers are laminated.

In the present embodiment, the above-mentioned AR layer (low refractive index layer) may be arranged on the anti-glare layer 3a. For example, when the optical laminate 11 according to the present embodiment is attached to the self-luminous display device, one of the factors that reduce the visibility of the image is the reflection of light at the interface between the air and the anti-glare layer. The AR layer reduces its surface reflection. The anti-glare layer 3a and the AR layer may each have a multi-layer structure in which two or more layers are laminated.

Further, in order to prevent the adhesion of contaminants and improve the ease of removing the adhered contaminants, a contamination prevention layer formed of a fluorine group-containing silane compound, a fluorine group-containing organic compound, or the like is provided on the antiglare layer 3a. It is preferable to stack them.

In the present embodiment, it is preferable to perform surface treatment on at least one of the base material 1 and the anti-glare layer 3a. If the surface of the base material 1 is surface-treated, the adhesion to the anti-glare layer 3a is further improved. Further, if the surface of the anti-glare layer 3a is surface-treated, the adhesion to the AR layer is further improved.

In order to prevent curling of the base material 1, the other surface of the anti-glare layer 3a may be treated with a solvent. Further, in order to prevent the occurrence of curl, a transparent resin layer may be formed on the other surface of the anti-glare layer 3a.

<Adhesive layer>
In the present embodiment, the pressure-sensitive adhesive layer 2 is preferably a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition selected from a photocurable pressure-sensitive adhesive composition containing a colorant and a solvent-type pressure-sensitive adhesive composition.

<Photocurable adhesive composition>
The photocurable pressure-sensitive adhesive composition contains a polymer, a photopolymerizable compound, and a photopolymerization initiator in addition to a colorant. That is, the photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer 2 of the present embodiment contains a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant. The pressure-sensitive adhesive layer 2 of the present embodiment is a pressure-sensitive adhesive layer having light absorption in visible light.

The pressure-sensitive adhesive layer formed by using the photocurable pressure-sensitive adhesive composition is a type that performs photo-curing (first form) and a type that does not perform photo-curing and is photo-cured after being bonded to a display panel described later. It is roughly divided into types (second form).

[First form]
In the pressure-sensitive adhesive layer of the first form, a photocurable pressure-sensitive adhesive composition containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant is applied onto a release film and photocured. Thereby, it can be formed.

<Photocurable adhesive composition>
(polymer)
Examples of the polymer contained in the photocurable pressure-sensitive adhesive composition include acrylic polymers, silicone-based polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy-based polymers, fluorine-based polymers, and natural rubbers. , Rubber-based polymers such as synthetic rubber, and the like. In particular, an acrylic polymer is preferably used because it exhibits adhesive properties such as appropriate wettability, cohesiveness and adhesiveness, and is also excellent in weather resistance and heat resistance.

The acrylic polymer contains (meth) acrylic acid alkyl ester as a main constituent monomer component. In addition, in this specification, "(meth) acrylic" means acrylic and / or methacryl. The amount of the (meth) acrylic acid alkyl ester with respect to the total amount of the monomer components constituting the acrylic polymer is preferably 50% by weight or more, more preferably 55% by weight or more, still more preferably 60% by weight or more.

As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably used. The (meth) acrylic acid alkyl ester may have a branched alkyl group or a cyclic alkyl group.

Specific examples of the (meth) acrylic acid alkyl ester having a chain alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and (meth). S-butyl acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-Ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate , (Meta) undecyl acrylate, (meth) dodecyl acrylate, (meth) isotridodecyl acrylate, (meth) tetradecyl acrylate, (meth) isotetradecyl acrylate, (meth) pentadecyl acrylate, (meth) Examples thereof include cetyl acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isooctadecil (meth) acrylate, and nonadecil (meth) acrylate. Examples of the (meth) acrylic acid alkyl ester having a preferable chain alkyl group used in the first form include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octadecyl (meth) acrylate, and (meth) acrylic. Dodecyl acid. The amount of the (meth) acrylic acid alkyl ester having a chain alkyl group with respect to the total amount of the monomer components constituting the acrylic polymer is, for example, about 40 to 90% by weight, and 45 to 80% by weight or 50 to 70% by weight. There may be.

Specific examples of the (meth) acrylic acid alkyl ester having an alicyclic alkyl group include cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate and the like. (Meta) acrylic acid cycloalkyl ester; (meth) acrylic acid ester having a bicyclic aliphatic hydrocarbon ring such as (meth) acrylic acid isobornyl; dicyclopentanyl (meth) acrylate, dicyclopentanyloxy Three rings such as ethyl (meth) acrylate, tricyclopentanyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate Examples thereof include (meth) acrylic acid esters having the above aliphatic hydrocarbon rings. Examples of the (meth) acrylic acid alkyl ester having a preferable alicyclic alkyl group used in the first form are cyclohexyl (meth) acrylic acid and isobornyl (meth) acrylic acid. The amount of the (meth) acrylic acid alkyl ester having an alicyclic alkyl group with respect to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and 5 to 40% by weight or 10 to 30% by weight. It may be.

The acrylic polymer may contain a polar group-containing monomer such as a hydroxyl group-containing monomer, a carboxy group-containing monomer, and a nitrogen-containing monomer as a constituent monomer component. When the acrylic polymer contains a polar group-containing monomer as a constituent monomer component, the cohesive force of the pressure-sensitive adhesive is enhanced, and the adhesive force tends to be improved. Preferred polar group-containing monomers used in the first form are hydroxyl group-containing monomers and nitrogen-containing monomers. The amount of the polar group-containing monomer (total of the hydroxy group-containing monomer, the carboxy group-containing monomer, and the nitrogen-containing monomer) with respect to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and is 5 to 40. It may be% by weight or 10 to 30% by weight.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and (meth) acrylic. Examples thereof include (meth) acrylic acid esters such as 8-hydroxyoctyl acid, 10-hydroxydecyl (meth) acrylic acid, 12-hydroxylauryl (meth) acrylic acid and (4-hydroxymethylcyclohexyl) -methyl (meth) acrylate. .. When a cross-linked structure is introduced into the polymer by an isocyanate cross-linking agent, the hydroxyl group can be a reaction point (cross-linking point) with the isocyanate group. Preferred hydroxyl group-containing monomers used in the first form are 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. The amount of the hydroxyl group-containing monomer with respect to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Examples of the carboxy group-containing monomer include acrylic monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, and carboxypentyl (meth) acrylate, and itaconic acid, maleic acid, fumaric acid, and crotonic acid. .. When a crosslinked structure is introduced into the polymer by an epoxy-based crosslinking agent, the carboxy group can be a reaction point (crosslinking point) with the epoxy group. A preferred carboxy group-containing monomer used in the first form is (meth) acrylic acid. The amount of the carboxy group-containing monomer with respect to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Examples of the nitrogen-containing monomer include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholin, (meth) acryloylmorpholin, and N-vinyl. Examples thereof include vinyl-based monomers such as carboxylic acid amides, N-vinylcaprolactam and acrylamide, and cyano group-containing monomers such as acrylonitrile and methacrylonitrile. The preferred nitrogen-containing monomer used in the first form is N-vinylpyrrolidone. The amount of the nitrogen-containing monomer with respect to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Acrylic polymers contain acid anhydride group-containing monomers, (meth) acrylic acid caprolactone adducts, sulfonic acid group-containing monomers, and phosphoric acid groups as monomer components other than the above (sometimes referred to as "other monomers"). Vinyl-based monomers such as monomers, vinyl acetate, vinyl propionate, styrene, α-methylstyrene, etc .; Epoxy group-containing monomers such as glycidyl (meth) acrylate; Polyethylene glycol (meth) acrylate, Polypropylene glycol (meth) acrylate Glycol-based acrylic ester monomers such as methoxyethylene glycol (meth) acrylate and methoxypolypropylene glycol (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and (meth) It may contain an acrylic acid ester-based monomer such as 2-methoxyethyl acrylate.

The glass transition temperature (Tg) of the polymer contained in the photocurable pressure-sensitive adhesive composition is preferably 0 ° C. or lower. The glass transition temperature of the polymer may be −5 ° C. or lower, −10 ° C. or lower, or −15 ° C. or lower. The glass transition temperature of the polymer is the peak top temperature of the loss tangent (tan δ) measured by dynamic viscoelasticity measurement. When a crosslinked structure is introduced into the polymer, the glass transition temperature may be calculated from the composition of the polymer based on the theoretical Tg. The theoretical Tg is calculated by the Fox formula described later.

A polymer can be obtained by polymerizing the above-mentioned monomer components by various known methods. The polymerization method is not particularly limited, but it is preferable to prepare the polymer by photopolymerization. Since the polymer can be prepared without using a solvent in photopolymerization, it is not necessary to dry and remove the solvent when forming the pressure-sensitive adhesive layer, and a thick pressure-sensitive adhesive layer can be uniformly formed.

In the preparation of the pressure-sensitive adhesive layer of the first form, it is preferable to prepare it as a polymer (prepolymer) having a low degree of polymerization in which a part of the monomer components remains unreacted. The composition used for preparing the prepolymer (composition for forming the prepolymer) preferably contains a photopolymerization initiator in addition to the monomer. The photopolymerization initiator may be appropriately selected depending on the type of monomer. For example, a photoradical polymerization initiator is used for the polymerization of an acrylic polymer. Examples of the photopolymerization initiator include a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, and a photoactive oxime-based photopolymerization initiator. Examples thereof include benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

At the time of polymerization, a chain transfer agent, a polymerization inhibitor (polymerization delaying agent) or the like may be used for the purpose of adjusting the molecular weight. Examples of the chain transfer agent include thiols such as α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. Examples thereof include α-methylstyrene dimer.

The polymerization rate of the prepolymer is not particularly limited, but is preferably 3 to 50% by weight, more preferably 5 to 40% by weight, from the viewpoint of obtaining a viscosity suitable for coating on a substrate. The polymerization rate of the prepolymer can be adjusted to a desired range by adjusting the type and amount of the photopolymerization initiator, the irradiation intensity and irradiation time of active light such as UV light, and the like. The polymerization rate of the prepolymer is a non-volatile component when heated at 130 ° C. for 3 hours, and is calculated by the following formula. The polymerization rate (nonvolatile content) of the pressure-sensitive adhesive layer is also measured by the same method.
Polymerization rate (%) = weight after heating / weight before heating x 100

As described above, the photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer contains a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant. For example, a photocurable pressure-sensitive adhesive composition can be obtained by adding a photopolymerizable compound, a photopolymerization initiator and a colorant to the prepolymer. Instead of using a prepolymer, a low molecular weight polymer (oligomer) is used, and the low molecular weight polymer is mixed with a photopolymerizable compound, a photopolymerization initiator and a colorant to prepare a photocurable pressure-sensitive adhesive composition. You may.

(Photopolymerizable compound)
The photopolymerizable compound contained in the photocurable pressure-sensitive adhesive composition has one or more photopolymerizable functional groups in one molecule. The photopolymerizable functional group may be radically polymerizable, cationically polymerizable or anionically polymerizable, but since it is excellent in reactivity, it is a radically polymerizable functional group having an unsaturated double bond (ethylenically unsaturated group). Is preferable.

The prepolymer contains an unreacted monomer with the polymer, and the unreacted monomer retains photopolymerizability. Therefore, it is not always necessary to add a photopolymerizable compound in the preparation of the photocurable pressure-sensitive adhesive composition. When the photopolymerizable compound is added to the prepolymer, the photopolymerizable compound to be added may be the same as or different from the monomer used for preparing the prepolymer.

When the polymer is an acrylic polymer, the compound added as the photopolymerizable compound is preferably a monomer or oligomer having a (meth) acryloyl group as the photopolymerizable functional group because it has high compatibility with the polymer. The photopolymerizable compound may be a polyfunctional compound having two or more photopolymerizable functional groups in one molecule. Examples of the photopolymerizable polyfunctional compound include polyfunctional (meth) acrylate. Examples of the polyfunctional (meth) acrylate include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, bisphenol A ethylene oxide-modified di (meth) acrylate, and bisphenol A propylene oxide. Modified di (meth) acrylate, alcandiol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, pentaeristol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate , Bifunctional (meth) acrylic acid esters such as urethane di (meth) acrylates; trifunctional (meth) acrylates such as pentaeristol tri (meth) acrylates, trimethylpropantri (meth) acrylates, and tri (meth) acrylates of ethoxylated isocyanuric acid. Meta) acrylic acid ester; tetrafunctional (meth) acrylic acid ester such as ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaeristol tetra (meth) acrylate, pentaeristol tetra (meth) acrylate; dipentaeryristol penta Examples thereof include (meth) acrylates and the like, and pentafunctional or higher functional (meth) acrylic acid esters such as dipentaeryristolhexa (meth) acrylate.

When a polyfunctional compound is used as the photopolymerizable compound, the amount of the polyfunctional compound used is preferably 10 parts by weight or less, more preferably 0.001 to 1 part by weight, based on 100 parts by weight of the polymer (including the prepolymer). Parts, more preferably 0.005 to 0.5 parts by weight. When the amount of the polyfunctional monomer used is excessively large, the viscosity of the pressure-sensitive adhesive layer after photocuring is low, and the adhesive strength may be poor. The amount of the polyfunctional compound used may be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight or less. The amount of the polyfunctional monomer used may be 0, and may be 0.001 part by weight or more, 0.01 part by weight or more, or 0.1 part by weight or more.

When a monomer forming a prepolymer is used as the photopolymerizable compound, a hydroxyl group-containing monomer is preferable, and 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are more preferable. When a hydroxyl group-containing monomer is used as the photopolymerizable compound, the amount of the hydroxyl group-containing monomer used is preferably 40 parts by weight or less, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the polymer (including the prepolymer). Yes, more preferably 5 to 20 parts by weight. The amount of the hydroxyl group-containing monomer used may be 40 parts by weight or less, 30 parts by weight or less, and 20 parts by weight or less. The amount of the hydroxyl group-containing monomer used may be 0, or may be 1 part by weight or more, 5 parts by weight or more, or 10 parts by weight or more.

(Photopolymerization initiator)
The photocurable pressure-sensitive adhesive composition contains a photopolymerization initiator. The photopolymerization initiator generates radicals, acids, bases and the like by irradiation with active light such as ultraviolet rays, and can be appropriately selected depending on the type of the photopolymerizable compound and the like. When the photopolymerizable compound is a compound having a (meth) acryloyl group (for example, a monofunctional or polyfunctional (meth) acrylate), it is preferable to use a photoradical polymerization initiator as the photopolymerization initiator. The photopolymerization initiator may be used alone or in combination of two or more.

If the photopolymerization initiator used in the preparation (polymerization) of the polymer (including the prepolymer) remains without being inactivated, the addition of the photopolymerization initiator may be omitted. When a photopolymerization initiator is added to the polymer, the photopolymerization initiator added may be the same as or different from the photopolymerization initiator used in the preparation of the polymer.

The photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition preferably has an absorption maximum in a wavelength region where light absorption by a colorant described later is small. Specifically, the photopolymerization initiator preferably has an absorption maximum in the wavelength region of 330 to 400 nm. Since the photopolymerization initiator has an absorption maximum in a region where the light absorption by the colorant is small, the curing inhibition by the colorant is suppressed, so that the polymerization rate can be sufficiently increased by the photocuring. Examples of the photoradical polymerization initiator having an absorption maximum in the wavelength region of 330 to 400 nm include hydroxyketones, benzyldimethylketals, aminoketones, acylphosphine oxides, benzophenones, trichloromethyl group-containing triazine derivatives and the like. ..

The content of the photopolymerization initiator in the photocurable pressure-sensitive adhesive composition is 0.01 to 10% by weight with respect to 100 parts by weight of the total amount of the monomers (monomer used for polymer preparation and photopolymerizable compound added to the polymer). The amount is about 0.05 to 5 parts by weight, preferably about 0.05 to 5 parts by weight.

(Colorant)
The photocurable pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer contains a colorant. The colorant may be a dye or a pigment as long as it can be dissolved or dispersed in the photocurable pressure-sensitive adhesive composition. Dyes are preferable because low haze can be achieved even with a small amount of addition, and unlike pigments, they do not have sedimentation properties and can be easily distributed uniformly. In addition, pigments are also preferable because they have high color development even when added in a small amount. When a pigment is used as a colorant, it preferably has low or no conductivity. In addition, when a dye is used, it is preferable to use it in combination with an antioxidant described later.

As the colorant, one that absorbs visible light and has ultraviolet transparency is used. The colorant preferably has an average transmittance at a wavelength of 330 to 400 nm higher than the average transmittance at a wavelength of 400 to 700 nm. The transmittance of the colorant is adjusted by using an appropriate solvent such as tetrahydrofuran (THF) or a dispersion medium (an organic solvent having a small absorption in the wavelength range of 330 to 700 nm) so that the transmittance at a wavelength of 400 nm is about 50 to 60%. Measure with a diluted solution or dispersion.

Examples of the ultraviolet-transparent black pigment having a smaller absorption of ultraviolet rays than the absorption of visible light include "9050BLACK" and "UVBK-0001" manufactured by Tokushiki. Examples of the ultraviolet-transparent black dye include "SOC-L-0123" manufactured by Orient Chemical Industries.

Carbon black and titanium black, which are generally used as black colorants, absorb ultraviolet rays more than they absorb visible light (the ultraviolet transmittance is smaller than the visible light transmittance). Therefore, when a colorant such as carbon black is added to the photocurable pressure-sensitive adhesive composition having sensitivity to ultraviolet rays, most of the ultraviolet rays irradiated for photocuring are absorbed by the colorant, and the amount of light absorbed by the photopolymerization initiator. Is small, and it takes time to photo-cure (the amount of integrated irradiation light increases). Further, when the thickness of the pressure-sensitive adhesive layer is large, the amount of ultraviolet rays reaching the surface opposite to the light irradiation surface is small, so that the photocuring tends to be insufficient even if the light irradiation is performed for a long time. On the other hand, by using a colorant having a higher transmittance of ultraviolet rays than visible light, it is possible to suppress curing inhibition caused by the colorant.

The content of the colorant in the photocurable pressure-sensitive adhesive composition is, for example, about 0.01 to 20 parts by weight with respect to 100 parts by weight of the total amount of the monomers, and the type of the colorant, the color tone of the pressure-sensitive adhesive layer, and the light. It may be set appropriately according to the transmittance and the like. The colorant may be added to the composition as a solution or dispersion dissolved or dispersed in an appropriate solvent.

(Silane coupling agent)
The photocurable pressure-sensitive adhesive composition may contain a silane coupling agent as long as the effects of the present invention are not impaired. When the photocurable pressure-sensitive adhesive composition contains a silane coupling agent, the adhesion reliability to the glass (particularly, the adhesion reliability to the glass in a high temperature and high humidity environment) is improved, which is preferable.

The silane coupling agent is not particularly limited, but is limited to γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-phenyl-aminopropyltrimethoxysilane. , 3-Acryloxypropyltrimethoxysilane and the like are preferable. Of these, γ-glycidoxypropyltrimethoxysilane is preferable. Further, as a commercially available product, for example, the product name "KBM-403" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned. The silane coupling agent may be used alone or in combination of two or more.

The content of the silane coupling agent in the photocurable pressure-sensitive adhesive composition is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.03 to 0.5 parts by weight, based on 100 parts by weight of the polymer. It is a part by weight.

(Other ingredients)
In the first embodiment, the photocurable pressure-sensitive adhesive composition may contain components other than the polymer, the photopolymerizable compound, the photopolymerization initiator and the colorant. For example, a chain transfer agent may be contained for the purpose of adjusting the photocuring rate or the like. Further, an oligomer or a tackifier may be contained for the purpose of adjusting the viscosity of the photocurable pressure-sensitive adhesive composition, adjusting the adhesive force of the pressure-sensitive adhesive layer, and the like. As the oligomer, for example, one having a weight average molecular weight of about 1000 to 30,000 is used. As the oligomer, an acrylic oligomer is preferable because it has excellent compatibility with an acrylic polymer. The photocurable pressure-sensitive adhesive composition may contain additives such as a plasticizer, a softener, an antioxidant, a filler, an antioxidant, a surfactant, and an antistatic agent.

[Second form]
The pressure-sensitive adhesive layer of the second form is a type of pressure-sensitive adhesive layer that is not photo-cured, and the photo-curable pressure-sensitive adhesive composition is formed in the form of a sheet. Since the pressure-sensitive adhesive layer of the second form contains the photopolymerizable compound in an unreacted state, the pressure-sensitive adhesive layer has photocurability.

<Photocurable adhesive composition>
The photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the second form contains a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant.

(polymer)
As the polymer contained in the photocurable pressure-sensitive adhesive composition, various polymers can be applied as in the first form, and an acrylic polymer is preferably used. The monomer components constituting the acrylic polymer are the same as those in the first form.

In order to introduce a crosslinked structure with a crosslinking agent described later, it is preferable that the monomer component constituting the polymer contains a hydroxy group-containing monomer and / or a carboxy group-containing monomer. For example, when an isocyanate-based cross-linking agent is used, it is preferable to contain a hydroxy group-containing monomer as a monomer component. When an epoxy-based cross-linking agent is used, it is preferable to contain a carboxy group-containing monomer as the monomer.

In the second form, since photocuring is not performed on the substrate, a polymer having a relatively large molecular weight is used as a polymer contained in the photocurable pressure-sensitive adhesive composition in order to form a solid (standard) pressure-sensitive adhesive layer. Used. The weight average molecular weight of the polymer is, for example, about 100,000 to 2 million.

Since the high molecular weight polymer is a solid, the photocurable pressure-sensitive adhesive composition is preferably a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution can be obtained by solution-polymerizing the monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene and the like are generally used as the solvent for solution polymerization. The solution concentration is usually about 20 to 80% by weight. The polymerization initiator includes an azo-based initiator, a peroxide-based initiator, a redox-based initiator that combines a peroxide and a reducing agent (for example, a combination of a persulfate and sodium hydrogen sulfite, a peroxide and an ascorbin). A thermal polymerization initiator such as (combination of sodium acid acid) is preferably used. The amount of the polymerization initiator used is not particularly limited, but is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, based on 100 parts by weight of the total amount of the monomer components forming the polymer. preferable.

(Photopolymerizable compound)
The photopolymerizable compound contained in the photocurable pressure-sensitive adhesive composition in the second form is the same as that described above for the first form, and a compound having one or more photopolymerizable functional groups is used.

(Photopolymerization initiator)
The photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition in the second form is the same as that described above for the first form, and preferably has an absorption maximum in the wavelength region of 330 to 400 nm. The amount of the photopolymerization initiator is about 0.01 to 10 parts by weight, preferably about 0.05 to 5 parts by weight, based on 100 parts by weight of the polymer.

(Colorant)
The colorant contained in the photocurable pressure-sensitive adhesive composition in the second form is the same as that described above for the first form, and the average transmittance at a wavelength of 330 to 400 nm is higher than the average transmittance at a wavelength of 400 to 700 nm. Larger ones are preferred.

(Crosslinking agent)
The photocurable pressure-sensitive adhesive composition of the second form preferably contains a crosslinkable crosslinkable agent with the above polymer. Specific examples of the cross-linking agent for introducing a cross-linked structure into the polymer include an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an oxazoline-based cross-linking agent, an aziridine-based cross-linking agent, a carbodiimide-based cross-linking agent, a metal chelate-based cross-linking agent, and the like. Be done. Of these, isocyanate-based cross-linking agents and epoxy-based cross-linking agents are preferable because they have high reactivity with the hydroxyl groups and carboxy groups of the polymer and the cross-linked structure can be easily introduced. These cross-linking agents react with functional groups such as hydroxyl groups and carboxy groups introduced into the polymer to form a cross-linked structure.

As the isocyanate-based cross-linking agent, polyisocyanate having two or more isocyanate groups in one molecule is used. Examples of the isocyanate-based cross-linking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2,4-tolylene diisocyanate. Aromatic isocyanates such as isocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate; trimethylolpropane / trimylene diisocyanate trimer adduct (eg, "Coronate L" manufactured by Toso), trimethylolpropane / hexamethylene Diisocyanate trimeric adduct (eg, Tosoh's "Coronate HL"), xylylene diisocyanate trimethylolpropane adduct (eg, Mitsui Chemicals' "Takenate D110N", hexamethylene diisocyanate isocyanurate (eg, Tosoh's "Coronate HL") Examples thereof include isocyanate additives such as "Coronate HX").

As the epoxy-based cross-linking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule is used. The epoxy group of the epoxy-based cross-linking agent may be a glycidyl group. Examples of the epoxy-based cross-linking agent include N, N, N', N'-tetraglycidyl-m-xylene diamine, diglycidyl aniline, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, 1, 6-Hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta Ellisritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, Examples thereof include resorcin diglycidyl ether and bisphenol-S-diglycidyl ether. As the epoxy-based cross-linking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX and "Tetrad X" and "Tetrad C" manufactured by Mitsubishi Gas Chemical Company may be used.

The amount of the cross-linking agent is about 0.01 to 5 parts by weight with respect to 100 parts by weight of the polymer, and may be 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more. It may be 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

(Other ingredients)
In addition to the above components, the photocurable pressure-sensitive adhesive composition of the second form includes oligomers, tackifiers, silane coupling agents, chain transfer agents, plasticizers, softeners, deterioration inhibitors, fillers, and antioxidants. , Surfactant, antistatic agent and the like may be contained.

<Solvent type pressure-sensitive adhesive composition>
In the present embodiment, the pressure-sensitive adhesive layer 2 may be a pressure-sensitive adhesive layer (third form) formed from a solvent-type pressure-sensitive adhesive composition containing a colorant. The solvent-type pressure-sensitive adhesive composition may contain at least a polymer and a solvent in addition to a colorant, and may contain a cross-linking agent . That is, the solvent-type pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer 2 of this embodiment contains a polymer, a solvent, and a colorant, and may contain a cross-linking agent if necessary. The pressure-sensitive adhesive layer 2 of the present embodiment is a pressure-sensitive adhesive layer having light absorption in visible light.

[Third form]
The pressure-sensitive adhesive layer of the third form contains a polymer, a solvent, and a colorant, and if necessary, a solvent-type pressure-sensitive adhesive composition containing a cross-linking agent is applied onto a release film, and the solvent is dried and removed. As a result, it can be formed.

The solvent-based pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the third form contains a polymer, a solvent, a colorant, and if necessary, a cross-linking agent.

(polymer)
As the polymer contained in the solvent-type pressure-sensitive adhesive composition, various polymers can be applied as in the first form, and an acrylic polymer is preferably used. The monomer components constituting the acrylic polymer are the same as those in the first form.

In the third form, in order to form a solid (standard) pressure-sensitive adhesive layer on the base material, a polymer having a relatively large molecular weight is used as the polymer contained in the solvent-type pressure-sensitive adhesive composition. The weight average molecular weight of the polymer is, for example, about 100,000 to 2 million.

The acrylic polymer contained in the solvent-based pressure-sensitive adhesive composition of the third form may be a (meth) acrylic block copolymer. When the pressure-sensitive adhesive layer 2 is formed from a solvent-type pressure-sensitive adhesive composition containing a (meth) acrylic block copolymer, it is excellent in step absorption and processability, and is therefore arranged on the substrate 5 of the display panel. Since it is possible to seal the plurality of LED chips without leaving any gaps on the steps and the workability is excellent, the problem that the adhesive layer protrudes from the end portion during storage is unlikely to occur.

In the present embodiment, the (meth) acrylic block copolymer has a high Tg segment having a glass transition temperature of 0 ° C. or higher and 100 ° C. or lower and a low Tg segment having a glass transition temperature of -100 ° C. or higher and lower than 0 ° C. It is preferable to have a peak of tan δ in a region of 0 ° C. or higher and a region of lower than 0 ° C., respectively.

In the present specification, "high Tg segment having a glass transition temperature of 0 ° C. or higher and 100 ° C. or lower" is simply referred to as "high Tg segment", and "low Tg segment having a glass transition temperature of -100 ° C. or higher and lower than 0 ° C." is simply referred to as "high Tg segment". "Low Tg segment", the peak of tan δ in the region above 0 ° C is simply "high temperature region tan δ peak", the peak of tan δ in the region below 0 ° C is simply "low temperature region tan δ peak", the high Tg segment and the low Tg A solvent-based pressure-sensitive adhesive containing "(meth) acrylic block copolymer A" as a (meth) acrylic block copolymer having a segment, a high temperature region tanδ peak, and a low temperature region tanδ peak, and the (meth) acrylic block copolymer A. The composition may be referred to as "solvent type pressure-sensitive adhesive composition A".

The “segment” in the high Tg segment and the low Tg segment refers to a partial structure constituting each block unit of the (meth) acrylic block copolymer A.

The structure of the (meth) acrylic block copolymer A may be a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. The structure of such a block copolymer may be appropriately selected according to the required physical properties of the block copolymer, but from the viewpoint of cost and ease of manufacture, it is preferably a linear block copolymer. The linear block copolymer may have any structure (arrangement), but from the viewpoint of the physical properties of the linear block copolymer or the physical properties of the solvent-type pressure-sensitive adhesive composition A, (AB) _n- type, ( _{AB) It is preferable that it is a block copolymer having at least one structure selected from the group consisting of n-} A type (n is an integer of 1 or more, for example, an integer of 1 to 3). In these structures, A and B mean segments composed of different monomer compositions. In the present specification, the segment represented by A constituting the linear block copolymer may be referred to as "A segment", and the segment represented by B may be referred to as "B segment".

Among these, AB type diblock copolymers represented by AB and ABA type triblock copolymers represented by ABA are selected from the viewpoints of ease of production, physical properties of the solvent-based pressure-sensitive adhesive composition A, and the like. Preferably, more preferably, it is an ABA type triblock copolymer. In ABA-type triblock copolymers, the cross-linking structure between block copolymers becomes higher due to pseudo-crosslinking between A segments at both ends, the cohesive force of block copolymers is improved, and higher adhesion (adhesive force) is exhibited. It is thought that it can be done. In the ABA type triblock copolymer, the two A segments located at both ends may be the same or different from each other.

When the (meth) acrylic block copolymer A is an ABA type triblock copolymer, at least one is a high Tg segment and at least one is a low Tg segment in two A segments and one B segment (three in total). It can be a segment. From the viewpoint of ease of production, physical properties of the solvent-based pressure-sensitive adhesive composition A, and the like, an ABA-type triblock copolymer in which the A segment is the high Tg segment and the B segment is the low Tg segment is preferable. In that case, an ABA-type triblock copolymer in which at least one of the two A segments is a high Tg segment and the B segment is a low Tg segment is preferred, and both of the two A segments are high Tg segments and the B segment. ABA-type triblock copolymers having a low Tg segment are more preferable.

As described above, the glass transition temperature (Tg) of the high Tg segment constituting the (meth) acrylic block copolymer A is 0 ° C. or higher and 100 ° C. or lower. When the Tg of the high Tg segment is in this range, the storage elastic modulus of the solvent-type pressure-sensitive adhesive composition A at room temperature (25 ° C.) can be easily controlled to be high, and the solvent-type pressure-sensitive adhesive composition A is hard and has excellent workability, and in a region exceeding 50 ° C. The storage elastic modulus tends to be significantly reduced, resulting in a highly fluid pressure-sensitive adhesive composition. From the viewpoint of improving the processability of the solvent-type pressure-sensitive adhesive composition A at room temperature (25 ° C.), the Tg of the high Tg segment is preferably 4 ° C. or higher, more preferably 6 ° C. or higher, further preferably 8 ° C. or higher. 10 ° C. or higher is even more preferable, and 12 ° C. or higher is particularly preferable. On the other hand, the Tg of the high Tg segment is 90 ° C. or lower from the viewpoint that the storage elastic modulus (G') of the solvent-type pressure-sensitive adhesive composition A is remarkably lowered in the region exceeding 50 ° C. and tends to have high fluidity. Preferably, 85 ° C. or lower is more preferable, 60 ° C. or lower is further preferable, 50 ° C. or lower is even more preferable, and 35 ° C. or lower is particularly preferable.

As described above, the Tg of the low Tg segment constituting the (meth) acrylic block copolymer A is −100 ° C. or higher and lower than 0 ° C. When the glass Tg of the low Tg segment is in this range, only the low Tg segment is fluidized at room temperature (25 ° C.), and an appropriate adhesive force is applied to the solvent-type pressure-sensitive adhesive composition A while ensuring processability. It tends to be granted. The Tg of the low Tg segment is preferably −95 ° C. or higher, more preferably −90 ° C. or higher, from the viewpoint that the storage elastic modulus of the solvent-type pressure-sensitive adhesive composition A does not easily decrease at room temperature (25 ° C.) and the processability can be improved. It is preferable, and more preferably −80 ° C. or higher. On the other hand, the Tg of the low Tg segment is preferably −5 ° C. or lower, more preferably −10 ° C. or lower, from the viewpoint of improving the appropriate adhesive strength and processability of the solvent-type pressure-sensitive adhesive composition A at room temperature (25 ° C.). Preferably, it is more preferably −20 ° C. or lower, even more preferably −30 ° C. or lower, and particularly preferably −40 ° C. or lower.

The difference between the Tg of the high Tg segment and the Tg of the low Tg segment (Tg of the high Tg segment-Tg of the low Tg segment) constituting the (meth) acrylic block copolymer A is not particularly limited, but is the same as that of the solvent-type pressure-sensitive adhesive composition A. From the viewpoint that the storage elastic modulus at room temperature (25 ° C.) is high and easy to control, it is hard and excellent in workability, and the storage elastic modulus is remarkably lowered in the region exceeding 50 ° C. to obtain a highly fluid pressure-sensitive adhesive composition. Therefore, it is preferably 30 ° C. or higher, more preferably 35 ° C. or higher, more preferably 40 ° C. or higher, more preferably 45 ° C. or higher, still more preferably 50 ° C. or higher, particularly preferably 55 ° C. or higher, and preferably 120 ° C. or lower. , More preferably 115 ° C. or lower, more preferably 110 ° C. or lower, more preferably 105 ° C. or lower, still more preferably 100 ° C. or lower, and particularly preferably 95 ° C. or lower.

The glass transition temperature (Tg) of the high Tg segment and the low Tg segment constituting the (meth) acrylic block copolymer A is a calculated glass transition temperature calculated from the following Fox formula. This calculated glass transition temperature is calculated based on the type and amount of each monomer component constituting the high Tg segment or the low Tg segment of the (meth) acrylic block copolymer A, and therefore the monomer component of each segment. It can be adjusted by selecting the type and amount of the above.

The calculated glass transition temperature (calculated Tg) can be calculated from the following Fox equation [1].
1 / Calculation Tg = W1 / Tg (1) + W2 / Tg (2) + ... + Wn / Tg (n) [1]
Here, W1, W2, ... Wn are the respective weight fractions (% by weight) of the monomer component (1), the monomer component (2), ... the monomer component (n) constituting the copolymer with respect to all the monomer components. ), And Tg (1), Tg (2), ... Tg (n) is a glass transition of the homopolymer of the monomer component (1), the monomer component (2), ... Represents temperature (unit is absolute temperature: K).
The glass transition temperature of homopolymers is known from various documents and catalogs, and is described in, for example, J. Brandup, EH Immergut, EA Grulke: Polymer Handbook: JOHNWILEY & SONS, INC. For monomers for which there are no numerical values in various documents, values measured by general thermal analysis, for example, differential thermal analysis, dynamic viscoelasticity measurement method, or the like can be adopted.

As described above, the temperature region in which the high temperature region tan δ peak of the (meth) acrylic block copolymer A appears is 0 ° C. or higher (for example, 0 ° C. or higher and 100 ° C. or lower). When the tan δ peak in the high temperature region is in this temperature range, the storage elastic modulus of the solvent-type pressure-sensitive adhesive composition A at room temperature (25 ° C.) can be easily controlled to be high, and it is hard and excellent in workability, and in the region exceeding 50 ° C. The storage elastic modulus tends to be significantly reduced, resulting in a highly fluid pressure-sensitive adhesive composition. From the viewpoint of improving the processability of the solvent-type pressure-sensitive adhesive composition A at room temperature (25 ° C.), the temperature at which the tanδ peak in the high temperature region appears is preferably 3 ° C. or higher, more preferably 6 ° C. or higher, and further 9 ° C. or higher. Preferably, 12 ° C. or higher is even more preferable, and 15 ° C. or higher is particularly preferable. On the other hand, the temperature at which the tan δ peak in the high temperature region appears is 90 ° C. from the viewpoint that the storage elastic modulus (G') of the solvent-type pressure-sensitive adhesive composition A is remarkably lowered in the region exceeding 50 ° C. and tends to have high fluidity. The following is preferable, 80 ° C. or lower is more preferable, 70 ° C. or lower is further preferable, 65 ° C. or lower is further preferable, and 60 ° C. or lower is particularly preferable.

The temperature region in which the low temperature region tan δ peak of the (meth) acrylic block copolymer A appears is less than 0 ° C. (for example, −100 ° C. or higher and lower than 0 ° C.) as described above. Since the tan δ peak in the low temperature region is in this temperature range, only the low Tg segment is fluidized at room temperature (25 ° C.), and an appropriate adhesive force is imparted to the solvent-type pressure-sensitive adhesive composition A while ensuring processability. There is a tendency to be able to do it. From the viewpoint that the storage elastic modulus of the solvent-type pressure-sensitive adhesive composition A does not easily decrease at room temperature (25 ° C.) and the processability can be improved, the temperature at which the tanδ peak in the low temperature region appears is preferably −95 ° C. or higher, preferably −90 ° C. The above is more preferable, −80 ° C. or higher is further preferable, and −70 ° C. or higher is further preferable. On the other hand, from the viewpoint of improving the appropriate adhesive strength and processability of the solvent-type pressure-sensitive adhesive composition A at room temperature (25 ° C.), the temperature at which the tanδ peak in the low temperature region appears is preferably −5 ° C. or lower, preferably −10 ° C. or lower. Is more preferable, −20 ° C. or lower is further preferable, −30 ° C. or lower is even more preferable, and −40 ° C. or lower is particularly preferable.

The maximum value of the tan δ peak in the high temperature region is not particularly limited, but is preferably 0.5 to 3.0. When the maximum value of the tan δ peak in the high temperature region is in this range, it is preferable in that excellent processability and shape stability of the (meth) acrylic block copolymer A can be realized. The maximum value of the tan δ peak in the high temperature region is preferably 0.6 or more, more preferably 0.7 or more, in that excellent workability can be realized. Further, the maximum value of the tan δ peak in the high temperature region is preferably 2.5 or less, more preferably 2.2 or less, from the viewpoint that dents are unlikely to occur.

The maximum value of the tan δ peak in the low temperature region is not particularly limited, but is preferably 0.1 to 2.0. When the maximum value of the tan δ peak in the low temperature region is in this range, it is preferable in that excellent processability and shape stability of the (meth) acrylic block copolymer A can be realized. The maximum value of the tan δ peak in the high temperature region is preferably 0.2 or more, more preferably 0.3 or more, in that excellent workability can be realized. Further, the maximum value of the tan δ peak in the low temperature region is preferably 1.5 or less, more preferably 1 or less, from the viewpoint that dents are unlikely to occur.

The high temperature region tan δ peak and the low temperature region tan δ peak, and the temperature and maximum value at which they appear are measured by dynamic viscoelasticity measurement.

The (meth) acrylic block copolymer A is composed of a plurality of segments (including a high Tg segment and a low Tg segment) obtained by polymerizing a monomer component, and the monomer component has a (meth) acryloyl group in the molecule. It contains a monomer (acrylic monomer) having.
The (meth) acrylic block copolymer A or each segment thereof preferably contains an acrylic monomer in an amount of 70% by weight or more, more preferably 80% by weight or more, and 90% by weight, based on the total amount (100% by weight) of the monomer components. It is particularly preferable to contain% or more.

Examples of the acrylic monomer constituting the (meth) acrylic block copolymer A or each segment thereof (including a high Tg segment and a low Tg segment) include an acrylic acid alkyl ester having a linear or branched alkyl group, and an acrylic acid alkyl ester having a linear or branched alkyl group. / Or, a monomer component derived from a methacrylic acid alkyl ester having a linear or branched alkyl group is contained as the main monomer unit having the largest weight ratio.

The (meth) acrylic acid alkyl ester having a linear or branched alkyl group for forming a segment of the (meth) acrylic block copolymer A is a (meth) acrylic acid having the above-mentioned chain alkyl group. Specific examples of alkyl esters can be given. As the (meth) acrylic acid alkyl ester for the segment, one kind of (meth) acrylic acid alkyl ester may be used, or two or more kinds of (meth) acrylic acid alkyl esters may be used. The (meth) acrylic acid alkyl ester for the segment is preferably methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, t-butyl acrylate, hexyl acrylate, heptyl acrylate, acrylic. At least one selected from the group consisting of octyl acid acid and isononyl acrylate is used.

The segment of the (meth) acrylic block copolymer A may contain a monomer unit derived from an alicyclic monomer. Examples of the alicyclic monomer for forming the monomer unit of the segment include specific examples of the (meth) acrylic acid alkyl ester having the alicyclic alkyl group described above. The alicyclic alkyl group may have a substituent. Examples of the substituent include a halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom) and a linear or branched alkyl group having 1 to 6 carbon atoms (eg, methyl group, ethyl group, n-propyl). Group, isopropyl group, etc.) and the like. The number of the substituents is not particularly limited and can be appropriately selected from 1 to 6. When there are two or more substituents, the two or more substituents may be the same or different. As the alicyclic monomer for the segment, one kind of alicyclic monomer may be used, or two or more kinds of alicyclic monomers may be used. The alicyclic monomer for the segment is preferably a cyclo having 4 to 10 carbon atoms which may have a substituent (eg, a linear or branched alkyl group having 1 to 6 carbon atoms). It is a (meth) acrylic acid cycloalkyl ester having an alkyl group, and more preferably at least one selected from the group consisting of cyclohexyl acrylate and 3,3,5-trimethylcyclohexyl (meth) acrylic acid is used.

The segment of the (meth) acrylic block copolymer A may contain a monomer unit derived from a hydroxyl group-containing monomer. The hydroxyl group-containing monomer is a monomer having at least one hydroxyl group in the monomer unit. When the segment in the (meth) acrylic block copolymer A contains a hydroxyl group-containing monomer unit, it is easy to obtain adhesiveness and appropriate cohesive force in the solvent-type pressure-sensitive adhesive composition A.

Specific examples of the above-mentioned hydroxyl group-containing monomer can be mentioned as the hydroxyl group-containing monomer for forming the monomer unit of the segment. As the hydroxyl group-containing monomer for the segment, one type of hydroxyl group-containing monomer may be used, or two or more types of hydroxyl group-containing monomers may be used. The hydroxyl group-containing monomer for the segment is preferably a hydroxyl group-containing (meth) acrylic acid ester, more preferably 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and methacrylic acid. At least one selected from the group consisting of 2-hydroxypropyl, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate is used.

The segment of the (meth) acrylic block copolymer A may contain a monomer unit derived from a nitrogen atom-containing monomer. A nitrogen atom-containing monomer is a monomer that will have at least one nitrogen atom in the monomer unit. When the segment of the (meth) acrylic block copolymer A contains a nitrogen atom-containing monomer unit, it is easy to obtain hardness and good adhesive reliability in the solvent-based pressure-sensitive adhesive composition A.

Specific examples of the above-mentioned nitrogen atom-containing monomer can be mentioned as examples of the nitrogen atom-containing monomer for forming the segment. As the nitrogen atom-containing monomer for the acrylic polymer, one kind of nitrogen atom-containing monomer may be used, or two or more kinds of nitrogen atom-containing monomers may be used. As the nitrogen atom-containing monomer for the segment, N-vinyl-2-pyrrolidone is preferably used.

The segment of the (meth) acrylic block copolymer A may contain a monomer unit derived from a carboxy group-containing monomer. The carboxy group-containing monomer is a monomer having at least one carboxy group in the monomer unit. When the segment of the (meth) acrylic block copolymer A contains a carboxy group-containing monomer unit, good adhesive reliability may be obtained in the solvent-based pressure-sensitive adhesive composition A.

Specific examples of the above-mentioned carboxy group-containing monomer can be mentioned as examples of the carboxy group-containing monomer for forming the monomer unit of the segment. As the carboxy group-containing monomer for the segment, one kind of carboxy group-containing monomer may be used, or two or more kinds of carboxy group-containing monomers may be used. Acrylic acid is preferably used as the carboxy group-containing monomer for the segment.

Further, examples of the monomer unit for forming the segment include the above-mentioned other monomers. The content of other monomers in the monomer unit constituting the segment of the (meth) acrylic block copolymer A is not particularly limited as long as it is 30% by weight or less with respect to the total amount of the monomer components (100% by weight), and the present invention. It is appropriately selected within the range that does not impair the effect of.

As the monomer component constituting the high Tg segment of the (meth) acrylic block copolymer A, it is easy to control the Tg of the high Tg segment within a predetermined range, and it is possible to impart desired physical properties to the (meth) acrylic block copolymer A. From the viewpoint, a (meth) acrylic acid alkyl ester having a linear alkyl group having 1 to 3 carbon atoms (hereinafter, may be referred to as _{"(meth) acrylic acid C 1-3 linear alkyl ester".} ), (Meta) acrylic acid alkyl ester having a branched alkyl group having 3 or 4 carbon atoms (hereinafter, _{may be referred to as "(meth) acrylic acid C 3-4} branched chain alkyl ester"). And at least one selected from the group consisting of an alicyclic monomer is preferably contained. Since homopolymers of these monomers have a relatively high Tg, it is easy to control the Tg of the high Tg segment within a predetermined range of the present invention by containing a monomer selected from these as a monomer component constituting the high Tg segment.

The alicyclic monomer has a cycloalkyl group having 4 to 10 carbon atoms which may have a substituent (eg, a linear or branched alkyl group having 1 to 6 carbon atoms) (meth). ) Acrylic acid cycloalkyl ester is preferable, and an acrylic having a cycloalkyl group having 4 to 10 carbon atoms, which may have a substituent (eg, a linear or branched alkyl group having 1 to 6 carbon atoms). Acid cycloalkyl esters are more preferred, and cyclohexyl acrylate (homopolymer Tg: 15 ° C.) and (meth) acrylic acid 3,3,5-trimethylcyclohexyl (homopolymer Tg: 52 ° C.) are particularly preferred.

When the alicyclic monomer is contained as the monomer component constituting the high Tg segment, the content of the alicyclic monomer with respect to the total amount (100% by weight) of the monomer component makes it easy to control the Tg of the high Tg segment within a predetermined range. From the viewpoint of imparting desired physical properties to the (meth) acrylic block copolymer A, it is preferably 10% by weight or more (for example, 10 to 100% by weight), more preferably 20% by weight or more, and more preferably 30% by weight or more. , More preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more. It is preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

As the (meth) acrylic acid C _1-3 linear alkyl ester, acrylic acid C _1-3 linear alkyl ester is preferable, and methyl acrylate (tg of homopolymer: 8 ° C.) is particularly preferable.
As the (meth) acrylic acid C _3-4 branched chain alkyl ester, acrylic acid C _3-4 branched chain alkyl ester is preferable, and t-butyl acrylate (tg of homopolymer: 35 ° C.) is particularly preferable.

_{When (meth) acrylic acid C 1-3} linear alkyl ester and / or (meth) acrylic acid C _3-4 branched chain alkyl ester is contained as a monomer component constituting the high Tg segment, (meth) acrylic acid The _{content of C 1-3} linear alkyl ester and / or (meth) acrylic acid C _3-4 branched chain alkyl ester with respect to the total amount (100% by weight) of the monomer components is such that Tg of the high Tg segment is within a predetermined range. From the viewpoint of being easy to control and imparting desired physical properties to the (meth) acrylic block copolymer A, it is preferably 10% by weight or more (for example, 10 to 100% by weight), more preferably 20% by weight or more, and more preferably. 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight. % Or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

As the monomer component constituting the low Tg segment of the (meth) acrylic block copolymer A, it is easy to control the Tg of the low Tg segment within a predetermined range, and it is possible to impart desired physical properties to the (meth) acrylic block copolymer A. From the viewpoint, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms (hereinafter, may be referred to as _{"(meth) acrylic acid C 4-18 alkyl ester".} ) And at least one selected from the group consisting of hydroxyl group-containing monomers. That is, since the homopolymer of the (meth) acrylic acid C _4-18 alkyl ester has a relatively low Tg, by containing this as a monomer component constituting the low Tg segment, the Tg of the low Tg segment is defined in the present invention. Easy to control within the range of. On the other hand, the hydroxyl group-containing monomer also has a relatively low Tg, and the (meth) acrylic block copolymer A can easily obtain adhesiveness and appropriate cohesive force. _{Therefore, it is more preferable to contain both the (meth) acrylic acid C 4-18} alkyl ester and the hydroxyl group-containing monomer as the monomer component constituting the low Tg segment of the (meth) acrylic block copolymer A.

As the (meth) acrylic acid C _4-18 alkyl ester, acrylic acid C _4-18 alkyl ester is preferable, and butyl acrylate (Tg of homopolymer: -55 ° C.) and 2-ethylhexyl acrylate (Tg of homopolymer). : -70 ° C), n-hexyl acrylate (Tg of homopolymer: -57 ° C), n-octyl acrylate (Tg of homopolymer: -65 ° C), isononyl acrylate (Tg of homopolymer: -58 ° C) ) Is particularly preferable.

_{When the (meth) acrylic acid C 4-18} alkyl ester is contained as the monomer component constituting the low Tg segment, the content of the (meth) acrylic acid C _4-18 alkyl ester with respect to the total amount (100% by weight) of the monomer component is From the viewpoint that the Tg of the low Tg segment can be easily controlled within a predetermined range and the desired physical properties can be imparted to the (meth) acrylic block copolymer A, it is preferably 10% by weight or more (for example, 10 to 100% by weight). It is preferably 20% by weight or more, more preferably 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably. It is 70% by weight or more, more preferably 80% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

As the hydroxyl group-containing monomer, a hydroxyl group-containing (meth) acrylic acid alkyl ester is preferable, and 4-hydroxybutyl acrylate (Tg of homopolymer: −65 ° C.) and 2-hydroxyethyl acrylate (Tg of homopolymer: −15 ° C.) are preferable. ℃) is particularly preferable.

When a hydroxyl group-containing monomer is contained as a monomer component constituting the low Tg segment, the content of the hydroxyl group-containing monomer with respect to the total amount (100% by weight) of the monomer component makes it easy to control the Tg of the low Tg segment within a predetermined range (meth). ) From the viewpoint of imparting desired physical properties to the acrylic block copolymer A, it is preferably 1% by weight or more, more preferably 1.5% by weight or more, more preferably 2% by weight or more, still more preferably 2.5% by weight. As mentioned above, it is particularly preferably 3% by weight or more. On the other hand, the content of the hydroxyl group-containing monomer with respect to the total amount (100% by weight) of the monomer components is preferably 50% by weight or less, more preferably 40% by weight or less, more preferably 30% by weight or less, still more preferably 20% by weight or less. It is more preferably 10% by weight or less, and particularly preferably 5% by weight or less.

_{When both the (meth) acrylic acid C 4-18} alkyl ester and the hydroxyl group-containing monomer are contained as the monomer components constituting the low Tg segment of the (meth) acrylic block copolymer A, the hydroxyl group-containing monomer and the (meth) acrylic acid The ratio of the C _4-18 alkyl ester (hydroxyl-containing monomer / (meth) acrylic acid C _4-18 alkyl ester) is not particularly limited, but the lower limit is preferably 1/99, more preferably 1.5 / 98. 5, more preferably 2/98, still more preferably 2.5 / 97.5, particularly preferably 3/97, while the upper limit is 50/50, more preferably 40/60, more preferably 30/97. 70, more preferably 20/80.

The (meth) acrylic block copolymer A can be produced by the living radical polymerization method of the above-mentioned monomer components. The living radical polymerization method maintains the simplicity and versatility of the conventional radical polymerization method, but is less likely to cause a termination reaction or chain transfer, and grows without deactivating the growth end. Therefore, the molecular weight distribution is precisely controlled and uniform. It is preferable in that it is easy to produce a polymer having a suitable composition.

In the living radical polymerization method, the high Tg segment may be produced first and the monomer of the low Tg segment may be polymerized on the high Tg segment; the low Tg segment may be produced first and the monomer of the high Tg segment may be produced on the low Tg segment. May be polymerized.

When the (meth) acrylic block copolymer A is an ABA-type triblock copolymer, it is preferable to produce the A segment first and polymerize the B segment monomer to the A segment from the viewpoint of ease of production.

As the living radical polymerization method, a known method can be used without particular limitation, and a method using a transition metal catalyst (ATRP method) depending on the method for stabilizing the polymerization growth end; reversible addition of a sulfur system. There are methods such as a method using a cleavage chain transfer agent (RAFT agent) (RAFT method); a method using an organic tellurium compound (TERP method). Among these methods, it is preferable to use the RAFT method from the viewpoints of the variety of monomers that can be used, the ease of controlling the molecular weight, and the fact that the metal does not remain in the solvent-type pressure-sensitive adhesive composition.

In the RAFT method, a known method can be used without particular limitation. For example, a step 1 (first RAFT polymerization) in which a monomer component is polymerized using a RAFT agent to prepare a first segment (first RAFT polymerization). ) And the first segment obtained in step 1, a monomer component having a different monomer composition from that in step 1 is further added and polymerized, and the second segment is added to the first segment in step 2 (first segment). 2 RAFT polymerization). After the second RAFT polymerization, the RAFT polymerizations of the third, fourth ... May be carried out in the same manner as the second RAFT polymerization, and the segments of the third, fourth ... May be further added.

The steps 1 and 2 can be carried out by a known and commonly used method, for example, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by irradiation with heat or active energy rays (thermal polymerization method, active energy ray polymerization). Method) and so on. Above all, the solution polymerization method is preferable in terms of transparency, water resistance, cost and the like. The polymerization is preferably carried out while avoiding contact with oxygen from the viewpoint of suppressing polymerization inhibition by oxygen. For example, it is preferable to carry out the polymerization in a nitrogen atmosphere.

When the (meth) acrylic block copolymer A is an ABA-type triblock copolymer, it is preferable to prepare the A segment in the step 1 and add the B segment to the obtained A segment in the step 2. .. In this case, the A segment is preferably a high Tg segment, and the B segment is preferably a low Tg segment.

As the RAFT agent, known ones can be used without particular limitation, and for example, compounds represented by the following formulas (1), (2), or formulas (3) (trithiocarbonate, dithioester, etc.) can be used. Dithiocarbonate) is preferred.

In formula (1), formula (2), or formula (3) [formulas (1) to (3)], R ^1a and R ^1b have the same or different hydrogen atoms, hydrocarbon groups, or cyano groups. show. R ^1c represents a hydrocarbon group which may have a cyano group. Examples ^{of the hydrocarbon groups as R 1a} , R ^1b , and R ^1c include hydrocarbon groups having 1 to 20 carbon atoms (straight, branched, or cyclic saturated or unsaturated hydrocarbon groups, etc.). Among them, hydrocarbon groups having 1 to 12 carbon atoms are preferable. Specific examples of the hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a cyclohexyl group, a dodecyl group, an octadecyl group and the like. A linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms; an aryl group having 6 to 12 carbon atoms such as a phenyl group; an arylalkyl group having a total carbon number of 7 to 10 such as a benzyl group and a phenethyl group, etc. Can be mentioned. Examples of the ^{hydrocarbon group having a cyano group as R 1c} include a group in which 1 to 3 hydrogen atoms of the above-mentioned hydrocarbon group are substituted with a cyano group.

In formulas (1) to (3), R ² represents a hydrocarbon group or a group in which a part of the hydrogen atom of the hydrocarbon group is substituted with a carboxyl group (for example, a carboxylalkyl group). Examples of the hydrocarbon group include hydrocarbon groups having 1 to 20 carbon atoms (straight chain, branched chain, cyclic saturated or unsaturated hydrocarbon groups, etc.), and among them, hydrocarbon groups having 1 to 12 carbon atoms. Hydrocarbon groups are preferred. Specific examples of the hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group, dodecyl group, octadecyl group and the like. Linear, branched, or cyclic alkyl groups having 1 to 12 carbon atoms; arylalkyl groups having a total carbon number of 7 to 10 such as benzyl group and phenethyl group can be mentioned.

In the RAFT method, the polymerization proceeds by reacting so that the raw material monomer is inserted between the sulfur atom in the RAFT agent represented by the formulas (1) to (3) and the methylene group adjacent to the sulfur atom.

Many of the RAFT agents are commercially available. Those that are not commercially available can be easily synthesized by known or conventional methods. In the present invention, one type of RAFT agent may be used alone, or two or more types may be used in combination.

RAFT agents include trithiocarbonates such as dibenzyltrithiocarbonate and S-cyanomethyl-S-dodecyltrithiocarbonate; cyanoethyl dithiopropionate, benzyl dithiopropionate, benzyl dithiobenzoate, acetoxyethyl dithiobenzoate and the like. Dithioesters; O-ethyl-S- (1-phenylethyl) dithiocarbonate, O-ethyl-S- (2-propoxyethyl) dithiocarbonate, O-ethyl-S- (1-cyano-1-methylethyl) Examples thereof include dithiocarbonates such as dithiocarbonate, of which trithiocarbonates are preferable, trithiocarbonates having a symmetrical structure in the formula (1) are more preferable, and dibenzyltrithiocarbonate and bis {4 are particularly preferable. -[Ethyl- (2-acetyloxyethyl) carbamoyl] benzyl} trithiocarbonate is preferred.

The step 1 can be performed by polymerizing the monomer components in the presence of a RAFT agent. The amount of the RAFT agent used in step 1 is usually 0.05 to 20 parts by weight, preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the total amount of the monomer components. With such an amount used, the reaction can be easily controlled, and the weight average molecular weight of the obtained segment can be easily controlled.
The step 2 can be performed by adding a monomer component to the polymerization reaction mixture obtained in the step 1 and further polymerizing the mixture.

The RAFT method is preferably carried out in the presence of a polymerization initiator. Examples of the polymerization initiator include ordinary organic polymerization initiators, and specific examples thereof include peroxides and azo compounds. Among these, azo compounds are preferable. The polymerization initiator may be used alone or in combination of two or more.

Examples of the peroxide-based polymerization initiator include benzoyl peroxide and tert-butyl permalate.
Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2'-azobis (2-cyclopropyl). Propionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile) , 2- (Carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis ( N, N'-dimethyleneisobutylamidine), 2,2'-azobis (isobutylamide) dihydrate, 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis (2-cyanopropanol), Examples thereof include dimethyl-2,2'-azobis (2-methylpropionate) and 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide].

The amount of the polymerization initiator used is usually 0.001 to 2 parts by weight, preferably 0.002 to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components. With such an amount, it is easy to control the weight average molecular weight of the obtained segment.

The RAFT method may be bulk polymerization that does not use a polymerization solvent, but it is preferable to use a polymerization solvent. Examples of the polymerization solvent include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane and n-octane; cyclopentane, cyclohexane, cycloheptane and cyclo. Alicyclic hydrocarbons such as octane; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene; diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole , Ethers such as phenylethyl ether and diphenyl ether; esters such as ethyl acetate, propyl acetate, butyl acetate and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone and cyclohexanone; N, N-dimethylformamide, N , N-dimethylacetamide, amides such as N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethylsulfoxide and sulfolanes. The polymerization solvent may be used alone or in combination of two or more.

The amount of the polymerization solvent used is not particularly limited, and is, for example, 0.01 mL or more, more preferably 0.05 mL or more, still more preferably 0.1 mL or more, and 50 mL or less with respect to 1 g of the monomer component. It is preferably 10 mL or less, still more preferably 1 mL or less.

The reaction temperature in the RAFT method is usually 60 to 120 ° C., preferably 70 to 110 ° C., and is usually carried out in an atmosphere of an inert gas such as nitrogen gas. This reaction can be carried out under normal pressure, pressurization or reduced pressure, and is usually carried out at normal pressure. The reaction time is usually 1 to 20 hours, preferably 2 to 14 hours.

The polymerization reaction conditions of the RAFT method described above can be applied to step 1 and step 2, respectively.

After completion of the polymerization reaction, the target (meth) acrylic block copolymer A can be separated from the obtained reaction mixture by removing the solvent used, residual monomers and the like by ordinary separation and purification means.

When the high Tg segment or the low Tg segment of the (meth) acrylic block copolymer A is prepared in the step 1, the weight average molecular weight (Mw) of the high Tg segment or the low Tg segment is not particularly limited, but is preferably 10. It is 000 to 1,000,000, more preferably 50,000 to 500,000, and even more preferably 100,000 to 300,000. The fact that the Mw of the high Tg segment or the low Tg segment is within this range is suitable for the above-mentioned effect of the present invention.
The Mw is the sum of Mw when two or more high Tg segments or low Tg segments are present in the (meth) acrylic block copolymer A.

The weight average molecular weight (Mw) of the (meth) acrylic block copolymer A is not particularly limited, but is preferably 200,000 (200,000) or more, more preferably 300,000 to 5,000,000, and even more preferably. Is between 400,000 and 2,500,000. It is suitable for the above-mentioned effect of the present invention that the Mw of the (meth) acrylic block copolymer A is within this range.

The molecular weight distribution (Mw / Mn) of the (meth) acrylic block copolymer A is not particularly limited, but is preferably larger than 1, more preferably 1.5 or more, still more preferably 2 or more, and particularly preferably 2. It is 5 or more, preferably 5 or less, more preferably 4.5 or less, still more preferably 4 or less, and particularly preferably 3.5 or less.

The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) are measured by the GPC method.

The content of the high Tg segment in the (meth) acrylic block copolymer A is preferably 10% by weight or more, more preferably 20% by weight or more, still more preferably 20% by weight or more in 100% by weight of the entire (meth) acrylic block copolymer A. It is 25% by weight or more, particularly preferably 30% by weight or more, preferably 95% by weight or less, more preferably 90% by weight or less, still more preferably 85% by weight or less.

The content of the low Tg segment in the (meth) acrylic block copolymer A is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 10% by weight or more in 100% by weight of the entire (meth) acrylic block copolymer A. It is 15% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, still more preferably 40% by weight or less, and particularly preferably 30% by weight or less.

The content of each of the segments and their ratio can be calculated from the weight average molecular weight (Mw) of each segment or the (meth) acrylic block copolymer A obtained in each step of the RAFT method, and when each segment is formed. It can be controlled by the charging ratio of the monomers, the polymerization rate of each monomer, and the like.

The content of the (meth) acrylic block copolymer A in the solvent-based pressure-sensitive adhesive composition A is not particularly limited, but is excellent in processability at room temperature (25 ° C.) and excellent step absorption in a region exceeding 50 ° C. From the viewpoint of obtaining the above, the amount is preferably 50% by weight or more (for example, 50 to 100% by weight), more preferably 60% by weight, based on the total amount (total weight, 100% by weight) of the solvent-type pressure-sensitive adhesive composition A. As mentioned above, it is more preferably 80% by weight or more, and particularly preferably 90% by weight or more.

(solvent)
Since the polymer in the third form is a solid, the solvent-based pressure-sensitive adhesive composition is a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution can be obtained by solution-polymerizing the monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

As the solvent, ethyl acetate, toluene and the like are generally used. The solution concentration is usually about 20 to 80% by weight.

Examples of the polymerization initiator when the monomer component is solution-polymerized include an azo-based initiator, a peroxide-based initiator, and a redox-based initiator that combines a peroxide and a reducing agent (for example, persulfate and sodium bisulfite). , A combination of peroxide and sodium ascorbate) and other thermal polymerization initiators are preferably used. The amount of the polymerization initiator used is not particularly limited, but is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, based on 100 parts by weight of the total amount of the monomer components forming the polymer. preferable.

(Colorant)
The solvent-based pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer of the third form contains a colorant. The colorant may be a dye or a pigment as long as it can be dissolved or dispersed in the solvent-type pressure-sensitive adhesive composition. Dyes are preferable because low haze can be achieved even with a small amount of addition, and unlike pigments, they do not have sedimentation properties and can be easily distributed uniformly. In addition, pigments are also preferable because they have high color development even when added in a small amount. When a pigment is used as a colorant, it preferably has low or no conductivity. When a dye is used, it is preferably used in combination with an antioxidant or the like.

The colorant contained in the solvent-type pressure-sensitive adhesive composition in the third form includes an ultraviolet-absorbing colorant in addition to the ultraviolet-transmissive colorant described above for the first form.

Examples of the ultraviolet-transparent black pigment include "9050BLACK" and "UVBK-0001" manufactured by Tokushiki. Examples of the ultraviolet-absorbing black dye include "VALIFAST BLACK 3810" and "NUBIAN Black PA-2802" manufactured by Orient Chemical Industries. Examples of the ultraviolet-absorbing black pigment include carbon black and titanium black.

The content of the colorant in the solvent-type pressure-sensitive adhesive composition is, for example, about 0.01 to 20 parts by weight with respect to 100 parts by weight of the total amount of the monomers, and the type of colorant, the color tone of the pressure-sensitive adhesive layer, and light transmittance. It may be set appropriately according to the rate and the like. The colorant may be added to the composition as a solution or dispersion dissolved or dispersed in an appropriate solvent.

(Crosslinking agent)
The solvent-based pressure-sensitive adhesive composition of the third form may contain a cross-linking agent capable of cross-linking with the above polymer. When the solvent-based pressure-sensitive adhesive composition contains a (meth) acrylic block copolymer, the pressure-sensitive adhesive layer of the third form has sufficient shape stability and may not contain a cross-linking agent.

When the solvent-type pressure-sensitive adhesive composition contains a cross-linking agent in the third form, the cross-linking agent is the same as that described above for the second form, and an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent are preferable.

When the solvent-type pressure-sensitive adhesive composition contains a cross-linking agent in the third embodiment, the content thereof is about 0.01 to 5 parts by weight with respect to 100 parts by weight of the polymer, and 0.05 parts by weight or more, 0. It may be 1 part by weight or more or 0.2 parts by weight or more, and may be 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

(Other ingredients)
In addition to the above components, the solvent-based pressure-sensitive adhesive composition of the third form includes oligomers, tackifiers, silane coupling agents, chain transfer agents, plasticizers, softeners, deterioration inhibitors, fillers, antioxidants, and the like. It may contain a surfactant, an antistatic agent and the like.

<Optical laminate>
In the present embodiment, the optical laminate 10 or 11 can be prepared by laminating the pressure-sensitive adhesive layer 2 on the surface 1b of the base material 1 which has not been subjected to the antireflection treatment and / or the antiglare treatment.

[First form]
The method of laminating the pressure-sensitive adhesive layer of the first form on the surface 1b is not particularly limited. For example, the photocurable pressure-sensitive adhesive composition of the first form is applied on a release film, molded on a sheet, and light. This can be done by curing to prepare a sheet-like pressure-sensitive adhesive layer and then laminating it on the surface 1b of the base material 1.

The photocurable pressure-sensitive adhesive composition of the first form is applied in a sheet form (layered form) on a release film, and the coating film of the photocurable pressure-sensitive adhesive composition on the release film is irradiated with ultraviolet rays to perform photo-curing. Thereby, the pressure-sensitive adhesive layer of the first form is obtained. When photocuring, a release film is further attached to the surface of the coating film, and the photocurable pressure-sensitive adhesive composition is sandwiched between the two release films and irradiated with ultraviolet rays to inhibit polymerization by oxygen. It is preferable to prevent it. Prior to photo-curing, the sheet-shaped coating film may be heated for the purpose of removing the solvent or dispersion medium of the colorant. When removing the solvent or the like by heating, it is preferable to carry out before attaching the release film.

As the film base material of the release film, a film made of various resin materials is used. Resin materials include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and (meth) acrylic resins. Examples thereof include polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, polyarylate-based resins, and polyphenylene sulfide-based resins. Among these, polyester resins such as polyethylene terephthalate are particularly preferable. The thickness of the film substrate is preferably 10 to 200 μm, more preferably 25 to 150 μm. Examples of the material of the release layer include a silicone-based release agent, a fluorine-based release agent, a long-chain alkyl-based release agent, a fatty acid amide-based release agent, and the like. The thickness of the release layer is generally about 10 to 2000 nm.

As a method of applying the photocurable pressure-sensitive adhesive composition on the release film, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat , Curtain coat, lip coat, die coater and the like are used.

The thickness of the pressure-sensitive adhesive layer containing the colorant is not particularly limited, and is appropriately set to be equal to or higher than the height of the light-emitting element so that the light-emitting elements arranged on the display panel described later can be sufficiently sealed. Just do it. For example, the thickness of the pressure-sensitive adhesive layer containing the colorant is 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2. times the height of the light emitting element. It is adjusted to be 5 times, more preferably 1.3 to 2.0 times. Specifically, the thickness of the pressure-sensitive adhesive layer containing the colorant is, for example, about 10 to 500 μm, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. As described above, since the colorant has ultraviolet transparency, the photocurable pressure-sensitive adhesive composition can be uniformly photo-cured in the thickness direction even when the thickness of the pressure-sensitive adhesive layer is large. .. The thickness of the pressure-sensitive adhesive layer containing the colorant may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less.

By irradiating the photocurable pressure-sensitive adhesive composition coated in layers on the release film with ultraviolet rays, active species are generated from the photopolymerization initiator, the photopolymerizable compound is polymerized, and the polymerization rate is increased (unreacted). With the reduction of the monomer), the liquid photocurable pressure-sensitive adhesive composition becomes a solid (standard) pressure-sensitive adhesive layer. The light source for ultraviolet irradiation is not particularly limited as long as the photopolymerization initiator contained in the pressure-sensitive adhesive composition can irradiate light in a sensitive wavelength range, and is an LED light source, a high-pressure mercury lamp, and ultra-high pressure mercury. Lamps, metal halide lamps, xenon lamps, etc. are used.

The integrated light amount of the irradiation light is, for example, about ^{100 to 5000 mJ / cm 2.} The polymerization rate (nonvolatile content) of the pressure-sensitive adhesive layer made of the photo-curable product of the photocurable pressure-sensitive adhesive composition is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more. The polymerization rate may be 93% or more or 95% or more. In order to reduce the non-volatile content, the pressure-sensitive adhesive layer may be heated to remove volatile components such as residual monomers, unreacted polymerization initiators, and solvents.

When the release films are provided on both sides of the pressure-sensitive adhesive layer, the thickness of one release film and the thickness of the other release film may be the same or different. The peeling force when peeling the release film temporarily attached to one surface from the pressure-sensitive adhesive layer and the peeling force when peeling the release film temporarily attached to the other surface from the pressure-sensitive adhesive layer are the same but different. You may. When the peeling forces of the two are different, the peeling film (light peeling film) having a relatively small peeling force is peeled off from the adhesive layer first and bonded to the surface 1b of the base material 1, thereby performing the first embodiment. An optical laminate having the pressure-sensitive adhesive layer of the above can be produced.

Further, the same as above except that the photocurable pressure-sensitive adhesive composition is applied to the surface 1b of the base material 1, molded on a sheet, and then a release film is attached to the surface of the coating film and irradiated with ultraviolet rays. It is also possible to produce an optical laminate having the pressure-sensitive adhesive layer of the first form.

The pressure-sensitive adhesive layer containing the colorant has light absorption in visible light. The total light transmittance of the optical laminate of the first form is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5 It may be less than or equal to%.

In the first form, as described above, as the colorant, one having a smaller absorption of ultraviolet rays than the absorption of visible light is used. Therefore, in the pressure-sensitive adhesive layer, the average transmittance T _UV at a wavelength of 330 to 400 nm is larger than _{the average transmittance T VIS at a wavelength of 400 to 700 nm. The average transmittance T VIS} of the pressure-sensitive adhesive layer at a wavelength of 400 to 700 nm is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less or 10% or less. It may be. Average transmittance T _UV wavelength 330~400nm of the adhesive layer is preferably at least 5%, 10% or more, 15% or more, may be 20% or more or 25% or more. The difference T _UV -T _VIS between T _UV and T _VIS is more than 3%, 5% or more, or may be more than 8% or 10% or more.

In the first embodiment, the shear storage elastic modulus G'25 ° C. at a temperature of 25 ° C. of the pressure-sensitive adhesive layer is, for example, about 10 to 1000 kPa, and may be 30 kPa or more, 50 kPa or more, 70 kPa or more or 100 kPa or more, and 700 kPa or less. , 500 kPa or less, 300 kPa or less, or 200 kPa or less. The shear storage elastic modulus G'85 ° C. at a temperature of the pressure-sensitive adhesive layer at 85 ° C. is, for example, about 3 to 300 kPa, may be 5 kPa or more, 7 kPa or more, or 10 kPa or more, and is 200 kPa or less, 150 kPa or less, or 100 kPa. It may be as follows. When the shear storage elastic modulus of the pressure-sensitive adhesive layer is within the above range, both appropriate flexibility and adhesiveness can be achieved. The shear storage elastic modulus is a value measured by dynamic viscoelasticity measurement at a frequency of 1 Hz.

[Second form]
In the optical laminate having the pressure-sensitive adhesive layer of the second form, the curable pressure-sensitive adhesive composition of the second form is applied onto a release film, the solvent is dried and removed as necessary, and the surface 1b of the base material 1 is removed. It can be prepared by laminating with. Further, in the optical laminate having the pressure-sensitive adhesive layer of the second form, the curable pressure-sensitive adhesive composition of the second form is applied on the surface 1b of the base material 1, and the solvent is dried and removed as necessary. Can also be prepared.

When the photocurable pressure-sensitive adhesive composition contains a solvent, it is preferable to dry the solvent after applying the pressure-sensitive adhesive composition. As the drying method, an appropriate method can be appropriately adopted depending on the purpose. The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 70 ° C. to 170 ° C. As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.

After applying the photocurable pressure-sensitive adhesive composition, a crosslinked structure is introduced into the polymer by heating as necessary. The heating temperature and heating time may be appropriately set depending on the type of the cross-linking agent used, and are usually in the range of 20 ° C. to 160 ° C. for about 1 minute to 7 days. The heating for drying the solvent may also serve as the heating for crosslinking. The introduction of the crosslinked structure does not necessarily have to be accompanied by heating.

The pressure-sensitive adhesive layer of the second form preferably has the same thickness, light transmittance, and shear storage elastic modulus as the pressure-sensitive adhesive layer of the first form. Since the pressure-sensitive adhesive layer of the second form is not photocured, it contains a photopolymerizable compound in an unreacted state. That is, the pressure-sensitive adhesive layer of the second form is a photocurable pressure-sensitive adhesive layer containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant.

The optical laminate having the photocurable pressure-sensitive adhesive layer of the second form can be photocured by irradiating with ultraviolet rays after being bonded to a display panel described later. The adhesive force between the optical laminate and the display panel can be changed by photocuring. For example, since the adhesive layer before photo-curing has high flexibility, it is possible to fill the uneven shape and steps formed by the light emitting elements arranged on the display panel, and after photo-curing, the adhesive force to the display panel. And adhesion reliability can be improved.

Ultraviolet rays are used as the active rays for photocuring the pressure-sensitive adhesive layer of the second form. Similar to the pressure-sensitive adhesive layer of the first form, since the colorant has a higher transmittance of ultraviolet rays than visible light, it is possible to suppress curing inhibition during photo-curing even when the pressure-sensitive adhesive layer is thick.

[Third form]
The optical laminate having the pressure-sensitive adhesive layer of the third form is prepared by applying the solvent-type pressure-sensitive adhesive composition on a release film, removing the solvent by drying, and laminating it on the surface 1b of the base material 1. Can be done. The optical laminate having the pressure-sensitive adhesive layer of the third form can also be prepared by applying the solvent-type pressure-sensitive adhesive composition on the surface 1b of the base material 1 and drying and removing the solvent.

After applying the solvent-type pressure-sensitive adhesive composition, the solvent is dried. As the drying method, an appropriate method can be appropriately adopted depending on the purpose. The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 70 ° C. to 170 ° C. As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.

After applying the solvent-type pressure-sensitive adhesive composition, heating may be performed if necessary. The heating temperature and heating time may be appropriately set depending on the type of the cross-linking agent used, and are usually in the range of 20 ° C. to 160 ° C. for about 1 minute to 7 days.

The pressure-sensitive adhesive layer of the third form preferably has the same thickness, light transmittance, and shear storage elastic modulus as the pressure-sensitive adhesive layer of the first form.

Further, when the solvent-type pressure-sensitive adhesive composition contains (meth) acrylic block copolymer A, the storage elastic modulus (G'25) of the pressure-sensitive adhesive layer at 25 ° C. is not particularly limited, but improves workability at room temperature. From the viewpoint, it is preferably 1 MPa or more, more preferably 1.5 MPa or more, more preferably 2 MPa or more, more preferably 2.5 MPa or more, more preferably 3 MPa or more, and from the viewpoint of improving the adhesive reliability at room temperature, 50 MPa. The following is preferable, more preferably 45 MPa or less, more preferably 40 MPa or less, still more preferably 35 MPa or less, and even more preferably 30 MPa or less.

When the solvent-based pressure-sensitive adhesive composition contains (meth) acrylic block copolymer A, the storage elasticity (G'50) of the pressure-sensitive adhesive layer at 50 ° C. is not particularly limited, but the step absorption in the region exceeding 50 ° C. 0.5 MPa or less, more preferably 0.45 MPa or less, more preferably 0.4 MPa or less, more preferably 0.35 MPa or less, more preferably 0.3 MPa or less, and 50 ° C. From the viewpoint of improving the handleability of the region exceeding the range, 0.0001 MPa or more is preferable, 0.0005 MPa or more is more preferable, 0.001 MPa or more is more preferable, 0.005 MPa or more is more preferable, and 0.01 MPa or more is more preferable. be.

When the solvent-based pressure-sensitive adhesive composition contains (meth) acrylic block copolymer A, the ratio of the storage elastic modulus at 25 ° C. to the storage elastic modulus at 50 ° C. (G'25 / G'50) of the pressure-sensitive adhesive layer is particularly high. Although not limited, from the viewpoint of improving workability at room temperature and improving step absorption in a region exceeding 50 ° C., 3 or more is preferable, 5 or more is more preferable, 10 or more is more preferable, and 15 or more is further preferable. It is particularly preferably 20 or more, and from the viewpoint of adhesive reliability, handleability, etc., it is preferably 100 or less, more preferably 95 or less, more preferably 90 or less, still more preferably 85 or less, and particularly preferably 80 or less. ..

The storage elastic modulus at 25 ° C. (G'25), the storage elastic modulus at 50 ° C. (G'25), and their ratio (G'25 / G'50) are measured by dynamic viscoelasticity measurement. Is to be done.

An optical laminate having an adhesive layer containing a colorant has light absorption in visible light. The optical laminate of the present embodiment preferably has a maximum transmittance at 350 nm to 450 nm.

The total light transmittance of the optical laminate of the present embodiment is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5 It may be less than or equal to%.

In the optical laminate of the present embodiment, a release film may be provided on the pressure-sensitive adhesive layer until use. Further, in the optical laminate of the present embodiment, a surface protective film may be laminated on the antireflection treatment and / or antiglare treatment surface 1a of the base material 1. The surface protective film formation is suitable for preventing the adhesion of scratches and stains during the manufacture, transportation, and shipment of the optical laminate and the optical products containing the same.

In addition to the base material 1, the pressure-sensitive adhesive layer 2, the release film, and the surface protective film, the optical laminate of the present embodiment includes other layers, for example, groups other than the base material 1, as long as the effects of the present invention are not impaired. A material, a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer 2, an intermediate layer, an undercoat layer, and the like may be provided on the surface or between arbitrary layers.

<Self-luminous display device>
In the self-luminous display device according to the second aspect of the present invention, a small number of light emitting elements are arranged on a wiring substrate, and each light emitting element is selectively emitted by a light emitting control means connected thereto. , A display device capable of directly displaying visual information such as characters, images, and moving images on a display screen by blinking each light emitting element. Examples of the self-luminous display device include a mini / micro LED display device and an organic EL (electroluminescence) display device. The optical laminate according to the first aspect of the present invention is particularly suitably used for manufacturing a mini / micro LED display device.

FIG. 3 is a schematic view (cross-sectional view) showing an embodiment of a self-luminous display device (mini / micro LED display device) according to the second aspect of the present invention. The mini / micro LED display device 20 according to the present embodiment includes a display panel in which a plurality of LED chips 6 are arranged on one side of a substrate 4, and an optical laminate 10 according to the first side surface of the present invention. The surface on the display panel on which the LED chips 6 are arranged is laminated with the adhesive layer 2 of the optical laminate 10.

In the present embodiment, a metal wiring layer 5 for sending a light emission control signal to each LED chip 6 is laminated on the substrate 4 of the display panel. The LED chips 6 that emit light of each color of red (R), green (G), and blue (B) are alternately arranged on the substrate 4 of the display panel via the metal wiring layer 5. The metal wiring layer 5 is formed of a metal such as copper, and reflects the light emitted from each LED chip 6 to reduce the visibility of the image. Further, the light emitted from each LED chip 6 of each color of RGB is mixed, and the contrast is lowered.

In the mini / micro LED display device of the present embodiment, each LED chip 6 arranged on the display panel is tightly sealed by the adhesive layer 2. Since the pressure-sensitive adhesive layer 2 contains a colorant, it has sufficient light-shielding properties in the visible light region. Since each LED chip 6 is sealed by the adhesive layer 2 having a high light-shielding property, reflection by the metal wiring layer 5 can be prevented. Further, since the adhesive layer 2 also seals between the LED chips 6 without gaps, it is possible to prevent color mixing between the LED chips 6 and improve the contrast.

As described above, in the optical laminate according to the present embodiment, since the pressure-sensitive adhesive layer contains a colorant, even when the metal adherend is laminated on the pressure-sensitive adhesive layer, the reflection and gloss of the metal surface are exhibited. Can be prevented. When the metal adherend is laminated on the pressure-sensitive adhesive layer of the optical laminate of the present embodiment, the reflectance of the base material surface 1a in the visible light region of 5 ° specular reflection is preferably 50% or less, and is preferably 30%. It is more preferably% or less, further preferably 15% or less, and particularly preferably 10% or less. The glossiness (based on JIS Z 8741-1997) of the base material surface 1a when the metal adherend is laminated on the pressure-sensitive adhesive layer of the optical laminate of the present embodiment is preferably 100% or less, preferably 80%. It is more preferably less than or equal to, more preferably 60% or less, and particularly preferably 50% or less.
As the metal adherend, copper, aluminum, stainless steel, or the like can be used.

Further, in the mini / micro LED display device of the present embodiment, the surface 1a of the base material 1 is subjected to antireflection treatment and / or antiglare treatment 3, so that external light is reflected and an image is reflected on the base material surface 1a. The deterioration of visibility due to crowding or the like is prevented, or the appearance such as glossiness is adjusted. FIG. 4 is a schematic view (cross-sectional view) showing another embodiment of the self-luminous display device (mini / micro LED display device) according to the second aspect of the present invention. The mini / micro LED display device 21 according to the present embodiment is the same as FIG. 3 except that the anti-glare layer 3a is formed on the surface 1a of the base material 1. The average inclination angle θa (°) of the anti-glare layer 3a of the mini / micro LED display device 21 according to the present embodiment is the same as described above.

The self-luminous display device of the present embodiment may include an optical member other than the display panel and the optical laminate. The optical member is not particularly limited, and examples thereof include a polarizing plate, a retardation plate, an antireflection film, a viewing angle adjusting film, and an optical compensation film. The optical member shall also include a member (design film, decorative film, surface protective plate, etc.) that plays a role of decoration and protection while maintaining the visibility of the display device and the input device.

The mini / micro LED display device of the present embodiment is manufactured by laminating a display panel in which a plurality of LED chips are arranged on one side of a substrate and an adhesive layer of an optical laminate according to the first side surface of the present invention. Can be manufactured by

Specifically, the display panel and the optical laminate having the pressure-sensitive adhesive layer of the first form can be attached by laminating under heating and / or pressure. When the optical laminate having the display panel and the adhesive layer of the second form is attached, it can be carried out by laminating under heating and / or pressurization and then performing photocuring. The photo-curing can be performed in the same manner as the photo-curing that forms the pressure-sensitive adhesive layer of the first form.

When the pressure-sensitive adhesive layer is formed from a solvent-type pressure-sensitive adhesive composition containing (meth) acrylic block copolymer A, the bonding is preferably performed by heating and pressurizing at 50 ° C. or higher. By heating and pressurizing at 50 ° C. or higher, the pressure-sensitive adhesive layer becomes highly fluid, sufficiently follows the steps of the LED chips arranged on the substrate, and can adhere to each other without gaps. The heating is carried out at 50 ° C. or higher, preferably 60 ° C. or higher, and more preferably 70 ° C. or higher. The pressurization is not particularly limited, but is performed at, for example, 1.5 atm or more, preferably 2 atm or more, and more preferably 3 atm or more. The heating and pressurizing can be performed using, for example, an autoclave or the like. After the mini / micro LED display device manufactured by this method is returned to room temperature (25 ° C.), the storage elastic modulus of the pressure-sensitive adhesive layer is increased, and the processability and adhesive reliability are improved.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples. The various characteristics in the following production examples were evaluated or measured by the following methods.

(Surface shape measurement)
A glass plate (thickness 1.3 mm) manufactured by Matsunami Glass Industry Co., Ltd. is attached to the surface of the anti-glare film on which the anti-glare layer is not formed with an adhesive, and a high-precision fine shape measuring instrument (trade name: Surfcoder ET4000) is attached. The surface shape of the anti-glare layer was measured under the condition of a cutoff value of 0.8 mm, and an average inclination angle θa was obtained. The high-precision fine shape measuring instrument automatically calculates the average inclination angle θa. The average inclination angle θa is based on JIS B 0601 (1994 edition).

(Haze)
By the method specified by JIS 7136, a haze meter (manufactured by Murakami Color Science Laboratory Co., Ltd., trade name "HN-150") was installed so that light was incident from the anti-glare layer surface of the anti-glare film, and the haze value was measured.

Manufacturing example 1
(Preparation of anti-glare film)
As a resin contained in the anti-glare layer, 100 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by DIC Corporation, trade name "Unidic 17-806", solid content 80%) was prepared. Styrene crosslinked particles (manufactured by Soken Kagaku Co., Ltd., trade name "MX-350H", weight average particle size: 3.5 μm, refractive index 1.59) per 100 parts by weight of the resin solid content of the resin. 14 parts by weight, 2.5 parts by weight of synthetic smectite (manufactured by Kunimine Kogyo Co., Ltd., trade name "Smecton SAN"), which is an organic clay as a styrene-imparting agent, photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907") ”) Was mixed in 5 parts by weight, and a leveling agent (manufactured by DIC Co., Ltd., trade name “Megafuck F-556”, 100% solid content) was mixed in 0.5 parts by weight. A light diffusing element forming material (coating liquid) was prepared by diluting this mixture with a mixed solvent of toluene / ethyl acetate (weight ratio 90/10) so that the solid content concentration was 30% by weight.
An anti-glare layer forming material (coating liquid) is applied to one side of a triacetyl cellulose (TAC) film (manufactured by Fujifilm, product name "TG60UL", thickness: 60 μm) that can function as a protective layer using a bar coater. A coating film was formed. Then, the transparent TAC film base material on which this coating film was formed was transported to a drying step. In the drying step, the coating film was dried by heating at 110 ° C. for 1 minute. Then, an ultraviolet ray having an integrated light amount of 300 mJ / cm ² is irradiated with a high-pressure mercury lamp, and the coating film is cured to form a light diffusing element having a thickness of 5.0 μm on one side of the TAC film to obtain an antiglare film 1. rice field. The haze value of the anti-glare film 1 was 42%. The θa (°) of the anti-glare layer of the anti-glare film 1 was 1.22.

Manufacturing example 2
(Preparation of anti-glare film)
As light diffusing fine particles, 14 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical Ltd., trade name "Silohobic 100", weight average particle size: 2.6 μm) was added, and the thickness after curing was increased to 7. An anti-glare film 2 was obtained by forming a light diffusing element on one side of the TAC film in the same manner as in Production Example 1 except that the thickness was set to 0 μm. The haze value of the anti-glare film 2 was 11%. The θa (°) of the anti-glare layer of the anti-glare film 2 was 1.43.

Manufacturing example 3
(Preparation of anti-glare film)
As a resin contained in the anti-glare layer forming material, 100 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by DIC Corporation, trade name "Unidic 17-806", solid content 80%) was prepared. 7 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical Ltd., trade name "Silohobic 702") and amorphous silica (Fuji Silysia Chemical Ltd.) per 100 parts by weight of the resin solid content of the resin. ), Product name "Silica Hobic 100") is 6.5 parts by weight, photopolymerization initiator (BASF, product name "OMNIRAD184") is 5 parts by weight, leveling agent (manufactured by DIC Corporation, product name) "Mega Fuck F-556") was mixed in an amount of 0.5 parts by weight. This mixture was diluted with toluene so that the solid content concentration became 30% to prepare an antiglare layer forming material (coating liquid).
As a translucent base material, a transparent plastic film base material (TAC film, manufactured by Fuji Film Co., Ltd., trade name "TD80UL", thickness: 80 μm) was prepared. A coating film of the anti-glare layer forming material (coating liquid) was formed on one side of the transparent plastic film base material using a bar coater. Then, the transparent plastic film base material on which this coating film was formed was transported to a drying step. In the drying step, the coating film was dried by heating at 110 ° C. for 1 minute. Then, an ultraviolet ray having an integrated light intensity of 300 mJ / cm ² was irradiated with a high-pressure mercury lamp, and the coating film was cured to form an anti-glare layer having a thickness of 5.0 μm to obtain an anti-glare film 3. The θa (°) of the anti-glare layer of the anti-glare film 3 was 3.5.

Manufacturing example 4
(Preparation of anti-glare film)
As anti-glare layer forming particles, 6.5 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical Ltd., trade name "Silohobic 702"), amorphous silica (manufactured by Fuji Silysia Chemical Ltd., trade name "Silohobic") Except that 6.5 parts by weight of 200 ") was added and 2.5 parts by weight of a thickener (manufactured by Corp Chemical, trade name" Lucentite SAN ") was added to make the thickness after curing treatment 8.0 μm. Obtained an antiglare film 4 in the same manner as in Production Example 3. The θa (°) of the anti-glare layer of the anti-glare film 4 was 2.3.

Production example 5
(Preparation of prepolymer)
In a separable flask equipped with a thermometer, agitator, a reflux cooling tube and a nitrogen gas introduction tube, 67 parts by weight of butyl acrylate (BA), cyclohexyl acrylate (CHA, manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat # 155") 14 By weight, 19 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.09 parts by weight of photopolymerization initiator (BASF, trade name "Irgacure 184"), and photopolymerization initiator (BASF, product) After 0.09 part by weight of the name "Irgacure 651") was added, nitrogen gas was flowed and nitrogen substitution was carried out for about 1 hour while stirring. Then, UVA was irradiated at 5 mW / cm ² to carry out polymerization, and the reaction rate was adjusted to 5 to 15% to obtain an acrylic prepolymer solution.

Production example 6
(Preparation of black adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) in the acrylic prepolymer solution obtained in Production Example 7 (the total amount of the prepolymer is 100 parts by weight). , 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Kogyo Kagaku, trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, And 0.3 part of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 651") was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
In 100 parts by weight of the photopolymerizable pressure-sensitive adhesive composition solution obtained above, 0.2 part by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 651") and a black pigment dispersion (manufactured by Tokushiki Co., Ltd., A photopolymerizable black pressure-sensitive adhesive composition solution was prepared by adding 4 parts by weight (trade name “Tokushiki 9050 Black”).

Production example 7
(Preparation of adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) in the acrylic prepolymer solution obtained in Production Example 7 (the total amount of the prepolymer is 100 parts by weight). , 0.12 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Kogyo Kagaku, trade name "KAYARAD DPHA") as a polyfunctional monomer, and 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent. Was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.

Production Example 8
(Preparation of adhesive sheet)
The black pressure-sensitive adhesive composition solution prepared in Production Example 6 is cured on the peeling surface of a release film R1 (manufactured by Mitsubishi Resin Co., Ltd., trade name "MRF # 38") having a thickness of 38 μm in which one side of the polyester film is a peeling surface. After that, the film was applied so as to have a thickness of 100 μm, and the polyester film was covered with a release film R2 (MRE # 38 manufactured by Mitsubishi Resin Co., Ltd.) having a release surface on one side to block air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name "FL15BL") under ^{the conditions of an illuminance of 5 mW / cm 2} and an integrated light intensity of 1300 mJ / cm ^2. As a result, a pressure-sensitive adhesive sheet 1 having a thickness of 100 μm in which the photocrosslinkable pressure-sensitive adhesive, which is a cured product of the black pressure-sensitive adhesive composition, was sandwiched between the release films R1 and R2 was obtained in the form of a base material-less pressure-sensitive adhesive sheet.
The illuminance value of the black light is a value measured by an industrial UV checker (manufactured by Topcon Corporation, trade name: UVR-T1, light receiving unit model UD-T36) having a peak sensitivity wavelength of about 350 nm.

Manufacturing example 9
(Preparation of adhesive sheet)
The photocrosslinkable adhesive, which is a cured product of the black adhesive composition, was sandwiched between the release films R1 and R2 in the same manner as in Production Example 10, except that the coating was applied so that the thickness after curing was 50 μm. A pressure-sensitive adhesive sheet 2 having a thickness of 50 μm was obtained in the form of a base material-less pressure-sensitive adhesive sheet.

Production Example 10
(Preparation of adhesive sheet)
The photocrosslinkable pressure-sensitive adhesive, which is a cured product of the pressure-sensitive adhesive composition, was sandwiched between the release films R1 and R2 in the same manner as in Production Example 10, except that the pressure-sensitive adhesive composition solution prepared in Production Example 7 was used. A pressure-sensitive adhesive sheet 3 having a thickness of 50 μm was obtained in the form of a base material-less pressure-sensitive adhesive sheet.

Examples 1-4
(Preparation of optical laminate)
One of the release films was peeled off from the pressure-sensitive adhesive sheet 1 obtained in Production Example 10, and the exposed adhesive surface was formed on the surface of the anti-glare films 1 to 4 obtained in Production Examples 1 to 4 in which the anti-glare layer was not formed. By laminating, an optical laminate composed of anti-glare films 1 to 4 / adhesive sheet 1 / release film was obtained.

Examples 5-8
(Preparation of optical laminate)
An optical laminate composed of antiglare films 1 to 4 / adhesive sheet 2 / release film was obtained in the same manner as in Examples 1 to 4 except that the adhesive sheet 2 obtained in Production Example 9 was used.

Comparative Examples 1 to 4
(Preparation of optical laminate)
An optical laminate composed of antiglare films 1 to 4 / adhesive sheet 3 / release film was obtained in the same manner as in Examples 1 to 6 except that the adhesive sheet 3 obtained in Production Example 10 was used.

Comparative Example 5
(Preparation of optical laminate)
From the TAC film / adhesive sheet 1 / release film in the same manner as in Examples 1 to 4 except that a TAC film (manufactured by Konica Minolta Co., Ltd., trade name "KC4UY") was used instead of the anti-glare film. An optical laminate was obtained.

Comparative Example 6
(Preparation of optical laminate)
From the TAC film / adhesive sheet 2 / release film in the same manner as in Examples 5 to 8 except that a TAC film (manufactured by Konica Minolta Co., Ltd., trade name "KC4UY") was used instead of the anti-glare film. An optical laminate was obtained.

Comparative Example 7
(Preparation of optical laminate)
From the TAC film / adhesive sheet 3 / release film in the same manner as in Comparative Examples 1 to 4, except that a TAC film (manufactured by Konica Minolta Co., Ltd., trade name "KC4UY") was used instead of the anti-glare film. An optical laminate was obtained.

(evaluation)
The transmittance, reflectance, and glossiness were measured using the optical laminates obtained in the above Examples and Comparative Examples. The measurement method is shown below. The measurement results are shown in Table 1.

(1) Transmittance The release film of the optical laminate obtained in the above Examples and Comparative Examples is peeled off, and light is incident on the spectrophotometer U4100 (manufactured by Hitachi High Technology) from the antiglare film / TAC film side. The transmittance (%) in the visible light region was measured. This transmittance is a Y value measured by a two-degree field of view (C light source) of JIS Z8701 and corrected for luminosity factor.

(2) Reflectance / Glossiness A plate was prepared by pasting an aluminum foil on a black acrylic plate and laminating it. The adhesive surface exposed by peeling off the release film of the optical laminate obtained in the above Examples and Comparative Examples was laminated on the aluminum foil side of the above plate to prepare a sample. The obtained sample was placed on a spectrophotometer U4100 (manufactured by Hitachi High-Technology Co., Ltd.) with an antiglare film / TAC film on the light source side, and the reflectance (%) in the visible light region of 5 ° specular reflection was measured. In addition, the obtained sample was transferred to a gloss meter (manufactured by Murakami Color Chemistry Laboratory, trade name "GM-26 PRO") by the method specified in JIS Z8741-1997, and an antiglare film / TAC film was placed on the light source side. It was installed and the glossiness (%) was measured.

10, 11 Optical laminate 1 Base material 2 Adhesive layer 3 Anti-reflection treatment and / or anti-glare treatment 3a Anti-glare layer 20, 21 Self-luminous display device (mini / micro LED display device)
4 Substrate 5 Wiring layer 6 Light emitting element (LED chip)

Claims (18)

An optical laminate containing a base material and a pressure-sensitive adhesive layer containing a colorant.
One side of the base material is anti-reflective and / or anti-glare treated.
An optical laminate in which the pressure-sensitive adhesive layer is laminated on a surface of the base material that has not been subjected to the antireflection treatment and / or the antiglare treatment. The optical according to claim 1, wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed of a photocurable pressure-sensitive adhesive composition containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant. Laminated body. The optical laminate according to claim 2, wherein the colorant has an average transmittance at a wavelength of 330 to 400 nm higher than an average transmittance at a wavelength of 400 to 700 nm. The optical laminate according to claim 2 or 3, wherein the photopolymerization initiator has at least one absorption maximum in the wavelength range of 330 to 400 nm. The optical laminate according to any one of claims 2 to 4, wherein the polymer is an acrylic polymer. The optical laminate according to any one of claims 2 to 5, wherein the glass transition temperature of the polymer is 0 ° C. or lower. The optical laminate according to any one of claims 2 to 6, wherein the photocurable pressure-sensitive adhesive composition further contains a cross-linking agent capable of cross-linking with the polymer. The optical laminate according to any one of claims 1 to 7, wherein the optical laminate has a maximum transmittance at 350 nm to 450 nm. The optical laminate according to any one of claims 1 to 8, wherein the total light transmittance of the pressure-sensitive adhesive layer is 80% or less. The optical laminate according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive layer has a thickness of 10 to 500 μm. The optical laminate according to any one of claims 1 to 10, wherein the shear storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25 ° C. is 10 to 1000 kPa. The optical laminate according to any one of claims 1 to 11, wherein the shear storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 85 ° C. is 3 to 300 kPa. The optical laminate according to any one of claims 1 to 12, wherein the anti-glare treatment is an anti-glare layer provided on one side of the base material. The anti-glare layer is formed using an anti-glare layer-forming material containing a resin, particles and a thixotropy-imparting agent.
The optical laminate according to claim 13, wherein the anti-glare layer has an aggregated portion that forms a convex portion on the surface of the anti-glare layer by aggregating the particles and the thixotropy-imparting agent. The optical laminate according to claim 14, wherein the average inclination angle θa (°) is in the range of 0.1 to 5.0 in the convex portion on the surface of the anti-glare layer. The optical laminate according to any one of claims 1 to 15, wherein a surface protective film is laminated on the antireflection-treated and / or anti-glare-treated surface of the base material. A display panel in which multiple light emitting elements are arranged on one side of the substrate,
A self-luminous display device comprising the optical laminate according to any one of claims 1 to 16.
A self-luminous display device in which a surface on which light emitting elements of the display panel are arranged and an adhesive layer of the optical laminate are laminated. The self-luminous display device according to claim 17, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate.

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