JP7387522B2 - optical laminate - Google Patents

Description

The present invention relates to an optical laminate suitable for sealing light-emitting elements of self-luminous display devices such as mini/micro LEDs.

2. Description of the Related Art In recent years, self-emissive display devices typified by mini/micro LED display devices (Mini/Micro Light Emitting Diode Displays) have been devised as next-generation display devices. The basic configuration of a mini/micro LED display device is that a substrate on which many 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 types of self-emitting display devices such as mini/micro LED display devices, such as a white backlight method, a white light emitting color filter method, and an RGB method. A black sealing material is sometimes used to prevent reflection of metal wiring or metal oxides such as ITO arranged on a substrate (for example, see Patent Documents 1 to 3). In particular, in an RGB type mini/micro LED display device in which LED chips are arranged, the black sealing material can also contribute to preventing RGB color mixing and improving contrast.

JP2019-204905A JP2017-203810A Special table 2018-523854 publication

As the black sealing material, a liquid curable resin or adhesive containing a black coloring agent (dye or pigment) is used. When using a liquid curable resin containing a black colorant, there is a problem in that the degree of blackness becomes uneven due to uneven thickness. In addition, pigments are often selected because they have superior heat resistance and weather resistance compared to dyes, but when using liquid curable resin in which pigments are dispersed, in addition to the above-mentioned thickness unevenness, liquid curable resin Problems also arise, such as uneven filling during resin filling and uneven pigment dispersion during flow. Additionally, since the surface of the liquid curable resin that has hardened after sealing does not have adhesion, it is necessary to laminate the cover member using an adhesive or the like, which creates the problem of requiring additional man-hours and materials. there were.

The present invention was devised under the above-mentioned circumstances, and an object of the present invention is to provide mini/micro LED display devices with improved anti-reflection function and/or anti-glare function and contrast. The objective is to reduce the number of steps and required members in the manufacturing process of light-emitting display devices.

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

That is, a first aspect of the present invention is an optical laminate including a base material and an adhesive layer containing a colorant, wherein one side of the base material is subjected to antireflection treatment and/or antiglare treatment. The present invention provides an optical laminate in which the adhesive layer is laminated on the side of the base material that is not subjected to the antireflection treatment and/or the antiglare treatment. By using the optical laminate of the first aspect of the present invention for manufacturing a self-luminous display device, the adhesive layer becomes a sealing material for sealing light emitting elements arranged on a display panel, and the base material Since it becomes the outermost cover member, there is no need to separately laminate a cover member after sealing, which reduces the number of steps and required members, and improves manufacturing efficiency.

In addition, the configuration in which the adhesive layer contains a coloring agent can be used to prevent uneven thickness, uneven filling, uneven pigment dispersion, etc., when sealing a light emitting element with the adhesive layer in the manufacture of a self-luminous display device. This is preferable because it is less likely to cause unevenness in blackness, and can also prevent reflections on metal wiring, prevent RGB color mixing, and improve contrast.
Furthermore, the configuration in which one side of the base material is treated with anti-reflection treatment and/or anti-glare treatment can be used to prevent deterioration of visibility due to reflection of external light or image reflection, and to adjust appearance such as gloss level. Preferred from this point of view.

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

In the optical laminate according to the first aspect of the invention, the polymer is preferably an acrylic polymer. The glass transition temperature of the polymer is preferably 0°C or lower. The adhesive layer preferably has a shear storage modulus of 3 to 300 kPa at a temperature of 85°C. These configurations are such that when the optical laminate according to the first aspect of the present invention is used for manufacturing a self-luminous display device, the adhesive layer is filled without gaps between the steps of the light emitting elements arranged on the display panel. , is preferable in that it has excellent level difference absorbability.

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

In the optical laminate according to the first aspect of the present invention, the antireflection treatment and/or antiglare treatment is preferably an antiglare 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, and the anti-glare layer is formed on the surface of the anti-glare layer by aggregation of the particles and the thixotropy-imparting agent. It is preferable to have an agglomerated portion forming a convex portion. In the convex portions 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 provide an anti-reflection function and/or anti-glare treatment to the surface of the optical laminate according to the first aspect of the present invention, and prevent a decrease in visibility due to reflection of external light or image reflection. Alternatively, it is preferable from the viewpoint of adjusting appearance such as glossiness.

In the optical laminate according to the first aspect of the present invention, a surface protection film may be further laminated on the antireflection-treated and/or anti-glare-treated surface of the base material. Such a configuration is suitable for preventing scratches and dirt from adhering during manufacturing, transportation, and shipping of the optical laminate and optical products including the same.

A second aspect of the present invention is a self-luminous display device comprising a display panel in which a plurality of light emitting elements are arranged on one side of a substrate, and the optical laminate of the first aspect of the present invention, A self-luminous display device is provided, in which a surface of a display panel on which light emitting elements are arranged and an adhesive layer of the optical laminate are laminated. In the self-luminous display device according to the second aspect 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. Such a configuration allows the self-luminous display device according to the second aspect of the present invention to prevent reflection of metal wiring on the substrate, prevent RGB color mixing, improve contrast, and improve visibility by reflecting external light and reflecting images. This is preferable in that it can prevent deterioration in properties or adjust appearance such as glossiness.

By using the optical laminate of the present invention in the production of a self-emissive display device, it is possible to reduce the number of steps and required components, and it is possible to reduce the number of processes and necessary materials, and it is possible to produce a self-emissive display device with improved anti-reflection and/or anti-glare functions and contrast. A display device can be efficiently manufactured.

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

The optical laminate according to the first aspect of the present invention is an optical laminate including a base material and an adhesive layer containing a colorant, wherein one side of the base material is treated with anti-reflection treatment and/or anti-glare treatment. The adhesive layer is laminated on the surface of the base material that is not subjected to the antireflection treatment and/or the antiglare treatment.

"Optical" in the optical laminate in the first aspect of the present invention means used for optical purposes, and more specifically, used for manufacturing products (optical products) using optical members. means to be Examples of optical products include image display devices and input devices such as touch panels, but self-luminous display devices such as mini/micro LED display devices and organic EL (electroluminescence) display devices are preferred, and in particular mini /Can be suitably used for manufacturing micro LED display devices.

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 diagram (cross-sectional view) showing one embodiment of the optical laminate according to the first aspect of the present invention.

In this embodiment, the optical laminate 10 includes a base material 1 and an adhesive layer 2 containing a colorant. The base material 1 has been subjected to anti-reflection treatment and/or anti-glare treatment 3 on one side 1a thereof. An adhesive layer 2 is laminated on the side 1b of the base material 1 that has not been subjected to anti-reflection treatment and/or anti-glare treatment.

<Base material>
In this embodiment, the base material 1 is not particularly limited, and examples thereof include glass, a transparent plastic film base material, and the like. The transparent plastic film substrate is not particularly limited, but preferably has excellent visible light transmittance (preferably 90% or more light transmittance) and excellent transparency (preferably haze value 5% or less). , for example, the transparent plastic film base material described in JP-A-2008-90263. As the transparent plastic film base material, one having optically low birefringence is suitably used. In this embodiment, the base material 1 can also be used as a cover member of a self-luminous display device, for example, and in this case, the transparent plastic film base material may be triacetyl cellulose (TAC), polycarbonate, acrylic A film formed from a polyolefin having a cyclic or norbornene structure or the like is preferred. Further, in this embodiment, the base material 1 may be the cover member itself. With such a configuration, it is possible to eliminate the step of separately laminating the cover member in manufacturing the self-luminous display device, thereby reducing the number of steps and required members, and improving production efficiency. Moreover, with such a configuration, the cover member can be made thinner. Note that when the base material 1 is a cover member, the surface 1a that has been subjected to anti-reflection treatment and/or anti-glare treatment becomes the outermost surface of the self-luminous display device, and visibility due to reflection of external light, reflection of images, etc. It plays the role of preventing deterioration in quality and adjusting appearance such as glossiness.

In this embodiment, the thickness of the base material 1 is not particularly limited, but in consideration of workability such as strength and handleability, and thin layer property, the thickness is preferably in the range of 10 to 500 μm, more preferably 20 μm. ~300 μm, optimally between 30 and 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, any known antireflection treatment can be used without particular limitation, such as antireflection (AR) treatment.

As the anti-reflection (AR) treatment, any known AR treatment can be applied without any particular restriction, and specifically, an optical thin film whose thickness and refractive index are strictly controlled on one side 1a of the base material 1 or the aforementioned 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 out the reversed phases of incident light and reflected light using light interference effects. The wavelength range of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength range with particularly high visibility is 450 to 650 nm, and the reflectance at the center wavelength of 550 nm is minimized. It is preferable to design the AR layer as follows.

The AR layer generally includes a multilayer antireflection layer having a laminated structure of two to five optical thin layers (thin films with strictly controlled thickness and refractive index), in which components with different refractive indexes are stacked in a predetermined manner. By forming multiple layers with a thickness of become. In the optical thin film, since high thickness accuracy is required, each layer is generally formed by a dry method such as vacuum evaporation, sputtering, CVD, etc.

As the anti-glare (AG) treatment, any 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 diagram (cross-sectional view) showing another embodiment of the optical laminate according to the first aspect of the present invention. In the optical laminate 11 of this embodiment, an anti-glare layer 3a is formed on one side 1a of the base material 1. As the anti-glare layer 3a, any known anti-glare layer can be used without limitation, and is generally formed as a layer in which inorganic or organic particles as an anti-glare agent are dispersed in a resin.

In this embodiment, the anti-glare layer 3a is formed using an anti-glare layer forming material containing a resin, particles and a thixotropy agent, and the particles and the thixotropy agent aggregate to form a surface of the anti-glare layer 3a. A convex portion is formed on the surface. With this configuration, the anti-glare layer 3a has excellent display characteristics that are both anti-glare and prevents white blurring, and also has no appearance defects even though the anti-glare layer is formed using particle aggregation. It is possible to prevent the formation 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 light or light. As the resin, it is also possible to use commercially available thermosetting resins, ultraviolet curable resins, and the like.

As the thermosetting 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 (such as ultraviolet rays), or electron beam, etc. can be used, for example, Silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as polyhydric alcohols, etc. can give. These may be used alone or in combination of two or more.

For example, a reactive diluent having at least one of an acrylate group and a methacrylate group can also be used in the resin. The reactive diluent can be, for example, the reactive diluent described in JP-A No. 2008-88309, and includes, for example, monofunctional acrylate, monofunctional methacrylate, polyfunctional acrylate, polyfunctional methacrylate, and the like. As the reactive diluent, trifunctional or higher functional acrylates or trifunctional or higher functional methacrylates are preferred. This is because the hardness of the anti-glare layer 3a can be made excellent. Examples of the reactive diluent include butanediol glycerol ether diacrylate, isocyanuric acid acrylate, isocyanuric acid methacrylate, and the like. These may be used alone or in combination of two or more.

The main functions of the particles for forming the anti-glare layer 3a are to provide anti-glare properties by making the surface of the anti-glare layer 3a uneven 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 refractive index difference between the particles and the resin. Examples of the particles include inorganic particles and organic particles. The inorganic particles are not particularly limited, and include, 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, etc. can be given. The organic particles are not particularly limited, and include, for example, polymethyl methacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin. Examples include resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyfluoroethylene resin powder, and the like. 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 diameter (D) of the particles is preferably within the range of 2.5 to 10 μm. By setting the weight average particle diameter of the particles within the above range, for example, it is possible to have better anti-glare properties and prevent white blurring. The weight average particle diameter of the particles is more preferably within the range of 3 to 7 μm. Note that the weight average particle diameter of the particles can be measured, for example, by the Coulter counting method. For example, using a particle size distribution measuring device (trade name: Coulter Multisizer, manufactured by Beckman Coulter) that uses the pore electrical resistance method, an electrolyte solution corresponding to the volume of the particles when the particles pass through the pores is measured. By measuring electrical resistance, the number and volume of the particles are determined, and the weight average particle diameter is calculated.

The shape of the particles is not particularly limited, and may be, for example, approximately spherical in the form of beads, or irregularly shaped such as powder, but is preferably approximately spherical, and more preferably has an aspect ratio. The particles are approximately spherical particles with a ratio of 1.5 or less, and most preferably spherical particles.

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, even more preferably 1. ~7 parts by weight. By setting it within the above range, for example, it is possible to have better anti-glare properties and prevent white blurring.

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

It is preferable that the organic clay is a clay that has been subjected to an organic treatment in order to improve its 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, Somasif MPE (trade names, all manufactured by 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 names, all manufactured by Hojun Co., Ltd.); Kunipia F, Kunipia G, Kunipia G4 (trade names, all manufactured by Kunimine Industries Co., Ltd.); Thixogel VZ, Clayton HT and Kraton 40 (trade names, both manufactured by Rockwood Additives).

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

The modified urea is a reaction product of an isocyanate monomer or its adduct 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 products 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 this embodiment, the height of the convex portion from the average roughness 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 still more preferably 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 that would cause defects in appearance on the convex portion. The anti-glare layer 3a of this embodiment has convex portions with such a height, thereby making it difficult to cause defects in appearance. Here, the height from the average line can be measured, for example, by the method described in JP-A-2017-138620.

The proportion 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 within the range of 3 to 12 μm. By setting the thickness (d) of the anti-glare layer 3a within the above range, for example, it is possible to prevent the optical laminate 11 from curling, and to avoid the problem of reduced productivity such as poor conveyance. Further, when the thickness (d) is within the above range, the weight average particle diameter (D) of the particles is preferably within 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 diameter (D) of the particles are in the above-mentioned combination, the anti-glare properties can be further improved. The thickness (d) of the anti-glare layer 3a is more preferably within the range of 3 to 8 μm.

The relationship between the thickness (d) of the anti-glare layer 3a and the weight average particle diameter (D) of the particles is preferably within the range of 0.3≦D/d≦0.9. By having such a relationship, it is possible to obtain an anti-glare layer that has better anti-glare properties, can prevent white blurring, and has no defects in appearance.

In the optical laminate 11 of this embodiment, as described above, the anti-glare layer 3a forms convex portions on the surface of the anti-glare layer 3a by aggregation of 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 surface direction of the anti-glare layer 3a. Thereby, 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 and prevent white blurring, and furthermore, can prevent appearance defects from occurring. can.

The surface shape of the anti-glare layer 3a can be arbitrarily designed by controlling the aggregation state of particles contained in the anti-glare layer forming material. The agglomeration state of the particles can be controlled by, for example, the material of the particles (for example, the chemical modification state of the particle surface, the affinity for solvents and resins, etc.), the type and combination of resins (binder) or solvents, and the like. Here, in this embodiment, the agglomeration state of the particles can be controlled by the thixotropy imparting agent contained in the anti-glare layer forming material. As a result, in this embodiment, the agglomeration state of the particles can be made as described above, and the convex portion can have a gentle shape.

In the optical laminate 11 of this embodiment, when the base material 1 is made of resin or the like, it is preferable to have a permeable layer at the interface between the base material 1 and the anti-glare layer 3a. The permeable layer is formed by permeating the base material 1 with a resin component included in the material for forming the anti-glare layer 3a. It is preferable that the permeable layer is formed because the adhesion between the base material 1 and the anti-glare layer 3a can be improved. The thickness of the permeable layer is preferably 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 triacetylcellulose and the resin contained in the anti-glare layer 3a is an acrylic resin, the permeable layer can be formed. The permeation layer can be confirmed and its thickness can be measured, for example, by observing a cross section of the optical laminate 11 with a transmission electron microscope (TEM).

In this embodiment, even when applied to the optical laminate 11 having such a permeable layer, it is possible to easily form a desired smooth surface unevenness that combines anti-glare properties and prevention of white blur. Can be done. The penetration layer is preferably formed thicker in order to improve adhesion as the base material 1 has poorer adhesion to the anti-glare layer 3a.

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

In this embodiment, the base material 1 on which the anti-glare layer 3a is formed preferably has a haze value within the range of 0 to 10%. The haze value is a haze value (cloudiness) according to JIS K 7136 (2000 edition). 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 keep the haze value within 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 within the above range, a clear image can be obtained and the contrast in a dark place can be improved.

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

In the above formula (1), Δa is the distance between the peaks and valleys of adjacent peaks in the standard length L of the roughness curve specified in JIS B 0601 (1994 edition), as shown in the formula (2) below. This is the 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 surface waviness components longer than a predetermined wavelength from a cross-sectional curve using a phase difference compensating high-pass filter. Further, the cross-sectional curve is a contour that appears at a cut end when the target surface is cut by a plane perpendicular to the target surface.
Δa=(h1+h2+h3...+hn)/L (2)

When θa is within the above range, anti-glare properties are better and white blur 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 the viscosity measured at a shear rate of 20 (1/s) using Rheostress 6000 manufactured by HAAKE, and β2 is the viscosity measured at a shear rate of 200 (1/s) using Rheostress 6000 manufactured by HAAKE. This is the viscosity measured under the following conditions.

When the Ti value is less than 1.3, appearance defects are likely to occur, and the anti-glare properties and white blurring properties are deteriorated. Furthermore, when the Ti value exceeds 3.5, the particles are less likely to aggregate and become more 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 liquid), apply the anti-glare layer forming material (coating liquid) to one side 1a of the base material 1 to form a coating film, and cure the coating film to form an anti-glare layer 3a. , can be manufactured. In this embodiment, a transfer method using a mold, a method of imparting an uneven shape by an appropriate method such as sandblasting, embossing roll, etc. 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 optimal solvent types and solvent ratios depending on the composition of the resin, the types and contents of the particles and the thixotropy-imparting agent, and the like. Examples of the solvent include, but are not limited to, 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, 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. Aromatic hydrocarbons such as benzene, toluene, xylene, etc.

For example, when triacetylcellulose (TAC) is used as the base material 1 to form the permeation layer, a good solvent for TAC can be suitably used. Examples of the solvent include ethyl acetate, methyl ethyl ketone, and cyclopentanone.

In addition, by appropriately selecting the solvent, the thixotropy imparting agent can exhibit good thixotropy to the anti-glare layer forming material (coating liquid). For example, when using organoclay, toluene and xylene can be preferably used alone or in combination; for example, when using an oxidized polyolefin, methyl ethyl ketone, ethyl acetate, propylene glycol monomethyl ether can preferably be used alone. They can be used or used in combination. For example, when using modified urea, butyl acetate and methyl isobutyl ketone can be suitably 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 (uniform coating surface). In this embodiment, the anti-glare layer 3a is used in cases where antifouling properties are required on the surface of the anti-glare layer 3a, or where an anti-reflection layer (low refractive index layer) or a layer containing an interlayer filler is formed on the anti-glare layer 3a. The leveling agent can be selected as appropriate. In this embodiment, for example, by including the thixotropy imparting agent, the coating liquid can exhibit thixotropy, so that coating unevenness is less likely to occur. Therefore, this embodiment has the advantage that, for example, the options for the leveling agent can be expanded.

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

If necessary, pigments, fillers, dispersants, plasticizers, ultraviolet absorbers, surfactants, antifouling agents, antioxidants, etc. may be added to the anti-glare layer forming material within a range that does not impair performance. You can. These additives may be used alone or in combination of two or more.

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

Examples of the method for coating the anti-glare layer forming material on one side 1a of the base material 1 include a fountain 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. Coating methods such as the following 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 combination of these methods.

The means for curing the coating film of the anti-glare layer forming material is not particularly limited, but ultraviolet curing is preferred. The irradiation amount of the energy ray source is preferably 50 to 500 mJ/cm ² as a cumulative exposure amount at an ultraviolet wavelength of 365 nm. If the irradiation amount is 50 mJ/cm ² or more, curing will be more sufficient, and the anti-glare layer formed will also have more sufficient hardness. Moreover, if it is 500 mJ/cm ² or less, coloring of the anti-glare layer to be formed can be prevented.

As described above, the anti-glare layer 3a can be formed on one side 1a of the base material 1. Note that 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 this embodiment is influenced by the thickness of the layer in pencil hardness, but preferably has a hardness of 2H or more.

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

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

In addition, in order to prevent the adhesion of contaminants and improve the ease of removing the adhered contaminants, a contamination prevention layer formed from a fluorine group-containing silane compound, a fluorine group-containing organic compound, etc. is provided on the anti-glare layer 3a. Lamination is preferred.

In this 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 with the anti-glare layer 3a will be further improved. Moreover, if the surface of the anti-glare layer 3a is subjected to a surface treatment, the adhesion with the AR layer is further improved.

In order to prevent the substrate 1 from curling, the other surface of the anti-glare layer 3a may be treated with a solvent. Furthermore, in order to prevent curling, a transparent resin layer may be formed on the other surface of the anti-glare layer 3a.

<Adhesive layer>
In this embodiment, the adhesive layer 2 is preferably an adhesive layer formed from an adhesive composition selected from a photocurable adhesive composition containing a colorant and a solvent-based adhesive composition.

<Photocurable adhesive composition>
The photocurable adhesive composition contains a polymer, a photopolymerizable compound, and a photopolymerization initiator in addition to a colorant. That is, the photocurable adhesive composition used to form the adhesive layer 2 of this embodiment contains a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant. The adhesive layer 2 of this embodiment is an adhesive layer that absorbs visible light.

The adhesive layer formed using a photocurable adhesive composition is of a type that is photocured (first form), and of a type that is not photocured but is photocured after being bonded to a display panel as described below. It is roughly divided into two types (second form).

[First form]
The adhesive layer of the first form applies a photocurable adhesive composition containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant onto a release film, and photocures the composition. By doing so, it can be formed.

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

The acrylic polymer contains a (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 relative to the total amount of monomer components constituting the acrylic polymer is preferably 50% by weight or more, more preferably 55% by weight or more, and even more preferably 60% by weight or more.

As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester in which the alkyl group has 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 (meth)acrylic acid alkyl esters having a chain alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylate. 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 , undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridodecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth) Examples include cetyl acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, and nonadecyl (meth)acrylate. Preferred (meth)acrylic acid alkyl esters having a chain alkyl group used in the first embodiment include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octadecyl (meth)acrylate, and (meth)acrylate. The acid is dodecyl. The amount of the (meth)acrylic acid alkyl ester having a chain alkyl group relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 40 to 90% by weight, 45 to 80% by weight, or 50 to 70% by weight. There may be.

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

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

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and (meth)acrylate. Examples include (meth)acrylic acid esters such as 8-hydroxyoctyl acid, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl (meth)acrylate. . When a crosslinked structure is introduced into the polymer by an isocyanate crosslinking agent, the hydroxyl group can serve as a reaction point (crosslinking point) with the isocyanate group. Preferred hydroxyl group-containing monomers used in the first embodiment include 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. The amount of the hydroxyl group-containing monomer relative to the total amount of 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 carboxy group-containing monomers include acrylic monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. . When a crosslinked structure is introduced into a polymer by an epoxy crosslinking agent, a carboxy group can become a reaction point (crosslinking point) with an epoxy group. A preferred carboxy group-containing monomer used in the first embodiment is (meth)acrylic acid. The amount of the carboxy group-containing monomer relative to the total amount of 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 nitrogen-containing monomers include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, and N-vinyl. Examples include vinyl monomers such as carboxylic acid amides, N-vinylcaprolactam, and acrylamide, and cyano group-containing monomers such as acrylonitrile and methacrylonitrile. A preferred nitrogen-containing monomer used in the first embodiment is N-vinylpyrrolidone. The amount of the nitrogen-containing monomer based on the total amount of 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 monomer components other than those listed above (sometimes referred to as "other monomers"), such as acid anhydride group-containing monomers, caprolactone adducts of (meth)acrylic acid, sulfonic acid group-containing monomers, and phosphoric acid group-containing monomers. Monomers, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene; 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)acrylate. It may also contain an acrylic ester 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 a polymer is the peak top temperature of 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 using the Fox equation described later.

A polymer can be obtained by polymerizing the above monomer components by various known methods. Although the polymerization method is not particularly limited, it is preferable to prepare the polymer by photopolymerization. In photopolymerization, a polymer can be prepared without using a solvent, so it is not necessary to dry and remove the solvent when forming an adhesive layer, and a thick adhesive layer can be formed uniformly.

In producing the adhesive layer of the first form, it is preferable to prepare a polymer (prepolymer) with a low degree of polymerization in which a portion of the monomer components remains unreacted. The composition used for preparing the prepolymer (composition for forming a 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 polymerizing acrylic polymers. Examples of photopolymerization initiators include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, Examples include benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and the like.

During polymerization, a chain transfer agent, a polymerization inhibitor (polymerization retardant), etc. may be used for the purpose of controlling the molecular weight. Examples of chain transfer agents 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 include α-methylstyrene dimer.

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

As mentioned above, the photocurable adhesive composition used to form the adhesive layer contains a polymer, a photopolymerizable compound, a photopolymerization initiator, and a colorant. For example, a photocurable adhesive composition can be obtained by adding a photopolymerizable compound, a photopolymerization initiator, and a colorant to a prepolymer. Instead of using a prepolymer, a photocurable adhesive composition is prepared by using a low molecular weight polymer (oligomer) and mixing a photopolymerizable compound, a photoinitiator, and a coloring agent with the low molecular weight polymer. You can.

(Photopolymerizable compound)
The photopolymerizable compound contained in the photocurable 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; however, since it has excellent reactivity, a radically polymerizable functional group having an unsaturated double bond (ethylenic unsaturated group) is preferable. is preferred.

The prepolymer contains monomers that have not reacted with the polymer, and the unreacted monomers retain photopolymerizability. Therefore, in preparing a photocurable pressure-sensitive adhesive composition, it is not necessarily necessary to add a photopolymerizable compound. When adding a photopolymerizable compound to the prepolymer, the photopolymerizable compound added may be the same as or different from the monomer used to prepare the prepolymer.

When the polymer is an acrylic polymer, the compound added as a photopolymerizable compound is preferably a monomer or oligomer having a (meth)acryloyl group as a photopolymerizable functional group because of its 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 photopolymerizable polyfunctional compounds include polyfunctional (meth)acrylates. Examples of polyfunctional (meth)acrylates 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, alkanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, pentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate , difunctional (meth)acrylic acid esters such as urethane di(meth)acrylate; trifunctional (such as pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and ethoxylated isocyanuric acid tri(meth)acrylate) meth)acrylic acid ester; tetrafunctional (meth)acrylic ester such as ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythol penta Examples include (meth)acrylic acid esters having five or more functional groups such as (meth)acrylate and dipentaerythol hexa(meth)acrylate.

When using a polyfunctional compound as a 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 prepolymer). parts, more preferably 0.005 to 0.5 parts by weight. If the amount of the polyfunctional monomer used is too large, the viscosity of the pressure-sensitive adhesive layer after photocuring may be 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, 0.001 parts by weight or more, 0.01 parts by weight or more, or 0.1 parts by weight or more.

When using a monomer that forms a prepolymer as the photopolymerizable compound, a hydroxyl group-containing monomer is preferred, and 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferred. When using a hydroxyl group-containing monomer as a 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 prepolymer). The amount is 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, or 20 parts by weight or less. The amount of the hydroxyl group-containing monomer used may be 0, 1 part by weight or more, 5 parts by weight or more, or 10 parts by weight or more.

(Photopolymerization initiator)
The photocurable adhesive composition contains a photopolymerization initiator. The photopolymerization initiator generates radicals, acids, bases, etc. upon irradiation with actinic rays such as ultraviolet rays, and can be appropriately selected depending on the type of photopolymerizable compound. 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 radical photopolymerization initiator as the photopolymerization initiator. The photopolymerization initiators may be used alone or in combination of two or more.

If the photopolymerization initiator used during the preparation (polymerization) of the polymer (including prepolymer) remains without being deactivated, the addition of the photopolymerization initiator may be omitted. When adding a photopolymerization initiator to a polymer, the photopolymerization initiator added may be the same as or different from the photopolymerization initiator used for preparing 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 the colorant described below is small. Specifically, the photopolymerization initiator preferably has an absorption maximum in the wavelength range of 330 to 400 nm. Since the photopolymerization initiator has an absorption maximum in a region where light absorption by the colorant is small, inhibition of curing by the colorant is suppressed, so that the polymerization rate can be sufficiently increased by photocuring. Examples of the photoradical polymerization initiator having an absorption maximum in the wavelength range of 330 to 400 nm include hydroxyketones, benzyldimethyl ketals, aminoketones, acylphosphine oxides, benzophenones, and trichloromethyl group-containing triazine derivatives. .

The content of the photopolymerization initiator in the photocurable adhesive composition is 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of monomers (monomer used for preparing the polymer 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 adhesive composition used to form the 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 preferred because they can achieve low haze even when added in small amounts, and are easy to distribute uniformly without settling unlike pigments. Pigments are also preferred because they provide high color development even when added in small amounts. If a pigment is used as a coloring agent, it is preferably one with low or no electrical conductivity. Furthermore, when a dye is used, it is preferable to use it together with an antioxidant, which will be described later.

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

Examples of ultraviolet-transparent black pigments that absorb less ultraviolet light than 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 Industry Co., Ltd.

Carbon black and titanium black, which are commonly used as black colorants, absorb more ultraviolet light than visible light (their ultraviolet transmittance is lower than their visible light transmittance). Therefore, when a colorant such as carbon black is added to a photocurable adhesive composition that is sensitive to ultraviolet light, most of the ultraviolet light irradiated for photocuring is absorbed by the colorant, and the amount of light absorbed by the photoinitiator is small and takes time to photocure (integrated amount of irradiation light increases). Furthermore, when the adhesive layer is thick, less ultraviolet rays reach the surface opposite to the light irradiation surface, so even if light irradiation is performed for a long time, photocuring tends to be insufficient. On the other hand, by using a colorant that has a higher transmittance for ultraviolet light than visible light, curing inhibition caused by the colorant can be suppressed.

The content of the colorant in the photocurable adhesive composition is, for example, about 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of monomers, and depends on the type of colorant, the color tone of the adhesive layer, and the light intensity. What is necessary is just to set it suitably according to transmittance|permeability etc. The colorant may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

(Silane coupling agent)
The photocurable pressure-sensitive adhesive composition may contain a silane coupling agent to the extent that the effects of the present invention are not impaired. It is preferable that the photocurable pressure-sensitive adhesive composition contains a silane coupling agent because it improves the reliability of adhesion to glass (particularly the reliability of adhesion to glass in a high temperature and high humidity environment).

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

The content of the silane coupling agent in the photocurable 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. Parts by weight.

(Other ingredients)
In the first form, the photocurable adhesive composition may contain components other than the polymer, photopolymerizable compound, photoinitiator, and colorant. For example, a chain transfer agent may be included for the purpose of adjusting the photocuring speed. Further, an oligomer or a tackifier may be included for the purpose of adjusting the viscosity of the photocurable adhesive composition and adjusting the adhesive force of the adhesive layer. As the oligomer, for example, one having a weight average molecular weight of about 1,000 to 30,000 is used. As the oligomer, acrylic oligomers are preferred because they have excellent compatibility with acrylic polymers. The photocurable adhesive composition may contain additives such as a plasticizer, a softener, a deterioration inhibitor, a filler, an antioxidant, a surfactant, and an antistatic agent.

[Second form]
The second type of adhesive layer is a type of adhesive layer that does not undergo photocuring, and is a sheet-shaped adhesive layer made of a photocurable adhesive composition. Since the adhesive layer of the second form contains the photopolymerizable compound in an unreacted state, the adhesive layer has photocurability.

<Photocurable adhesive composition>
The photocurable adhesive composition used to form the second type of adhesive layer 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 used, as in the first embodiment, and acrylic polymers are preferably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.

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

In the second form, photocuring is not performed on the base material, so in order to form a solid (standard shape) adhesive layer, a polymer with a relatively large molecular weight is used as the polymer contained in the photocurable adhesive composition. used. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

Since high molecular weight polymers are solid, the photocurable 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 monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene, etc. are generally used as a solvent for solution polymerization. The solution concentration is usually about 20 to 80% by weight. Polymerization initiators include azo initiators, peroxide initiators, redox initiators that combine peroxide and reducing agent (for example, combinations of persulfate and sodium bisulfite, peroxide and ascorbic acid). A thermal polymerization initiator such as a combination of sodium acid and the like is preferably used. The amount of the polymerization initiator used is not particularly limited, but for example, it 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 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 embodiment is the same as that described above for the first embodiment, and preferably has an absorption maximum in the wavelength range 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 adhesive composition in the second form is the same as that described above for the first form, and the average transmittance in the wavelength range of 330 to 400 nm is higher than the average transmittance in the wavelength range of 400 to 700 nm. Larger ones are preferred.

(Crosslinking agent)
The photocurable pressure-sensitive adhesive composition of the second form preferably contains a crosslinking agent capable of crosslinking with the above polymer. Specific examples of crosslinking agents for introducing crosslinked structures into polymers include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, metal chelate crosslinking agents, etc. It will be done. Among these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred because they have high reactivity with the hydroxyl groups and carboxyl groups of polymers and can easily introduce a crosslinked structure. These crosslinking agents react with functional groups such as hydroxyl groups and carboxy groups introduced into the polymer to form a crosslinked structure.

As the isocyanate crosslinking agent, polyisocyanate having two or more isocyanate groups in one molecule is used. Examples of the isocyanate-based crosslinking 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/tolylene diisocyanate trimer adduct (for example, "Coronate L" manufactured by Tosoh), trimethylolpropane/hexamethylene Diisocyanate trimer adducts (e.g. "Coronate HL" manufactured by Tosoh), trimethylolpropane adducts of xylylene diisocyanate (e.g. "Takenate D110N" manufactured by Mitsui Chemicals), isocyanurates of hexamethylene diisocyanate (e.g. "Coronate HL" manufactured by Tosoh), Examples include isocyanate adducts such as "Coronate HX").

As the epoxy crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule is used. The epoxy group of the epoxy crosslinking agent may be a glycidyl group. Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylene diamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)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 Erythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris(2-hydroxyethyl) isocyanurate, Examples include resorcin diglycidyl ether and bisphenol-S-diglycidyl ether. As the epoxy crosslinking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX, "Tetrad X" and "Tetrad C" manufactured by Mitsubishi Gas Chemical may be used.

The amount of the crosslinking agent is about 0.01 to 5 parts by weight per 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. , 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-mentioned components, the photocurable adhesive composition of the second form also contains an oligomer, a tackifier, a silane coupling agent, a chain transfer agent, a plasticizer, a softener, an anti-degradation agent, a filler, and an antioxidant. , a surfactant, an antistatic agent, and the like.

<Solvent type adhesive composition>
In this embodiment, the adhesive layer 2 may be an adhesive layer (third form) formed from a solvent-based adhesive composition containing a colorant. In addition to the colorant, the solvent-based adhesive composition contains at least a polymer and a solvent, and may also contain a crosslinking agent . That is, the solvent-based adhesive composition used to form the adhesive layer 2 of this embodiment contains a polymer, a solvent, and a colorant, and may also contain a crosslinking agent if necessary. The adhesive layer 2 of this embodiment is an adhesive layer that absorbs visible light.

[Third form]
The third type of adhesive layer contains a polymer, a solvent, and a colorant, and a solvent-based adhesive composition containing a crosslinking agent if necessary is applied onto a release film, and the solvent is dried and removed. By doing so, it can be formed.

The solvent-based adhesive composition used to form the third type of adhesive layer contains a polymer, a solvent, a colorant, and optionally a crosslinking agent.

(polymer)
As the polymer contained in the solvent-based adhesive composition, various polymers can be used, as in the first embodiment, and acrylic polymers are preferably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.

In the third embodiment, in order to form a solid (standard shape) adhesive layer on a substrate, a polymer having a relatively large molecular weight is used as the polymer contained in the solvent-based adhesive composition. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

The acrylic polymer contained in the third embodiment of the solvent-based adhesive composition may be a (meth)acrylic block copolymer. When the adhesive layer 2 is formed from a solvent-based adhesive composition containing a (meth)acrylic block copolymer, it has excellent step absorbability and processability, so it can be arranged on the substrate 5 of the display panel. It is possible to seal the steps of a plurality of LED chips without leaving any air bubbles and have excellent processability, so that the problem of the adhesive layer protruding from the edges during storage is less likely to occur.

In this embodiment, the (meth)acrylic block copolymer has a high Tg segment having a glass transition temperature of 0°C or more and 100°C or less, and a low Tg segment having a glass transition temperature of -100°C or more and less 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 this 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 tan δ peak in the region above 0°C is simply "high temperature region tan δ peak", the tan δ peak in the region below 0° C. is simply "low temperature region tan δ peak", the high Tg segment and the low Tg A (meth)acrylic block copolymer having a segment, the high-temperature region tan δ peak, and the low-temperature region tan δ peak is “(meth)acrylic block copolymer A,” and a solvent-based adhesive containing the (meth)acrylic block copolymer A. The composition may be referred to as "solvent-based adhesive composition A."

The "segment" in the high Tg segment and the low Tg segment refers to a partial structure that constitutes 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-shaped) block copolymer, or a mixture thereof. The structure of such a block copolymer may be appropriately selected depending on the desired physical properties of the block copolymer, but from the viewpoint of cost and ease of manufacture, a linear block copolymer is preferable. In addition, 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-based adhesive composition A, (AB) _n- type, It is preferable that the block copolymer has at least one type of structure selected from the group consisting of (AB) _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 refer to segments composed of different monomer compositions. In this specification, the segment represented by A constituting the linear block copolymer may be referred to as an "A segment", and the segment represented by B may be referred to as a "B segment".

Among these, from the viewpoint of ease of manufacture and physical properties of solvent-based adhesive composition A, AB type diblock copolymers represented by AB and ABA type triblock copolymers represented by ABA are preferred. Preferably, an ABA type triblock copolymer is more preferable. The ABA type triblock copolymer has a more advanced crosslinked structure between the block copolymers due to pseudo-crosslinking between the A segments at both ends, which improves the cohesive force of the block copolymer and develops higher adhesion (adhesive force). It is thought that this can be done. In addition, in the ABA type triblock copolymer, the two A segments located at both ends may be the same or different.

When (meth)acrylic block copolymer A is an ABA type triblock copolymer, at least one of two A segments and one B segment (total of three) is a high Tg segment, and at least one other is a low Tg segment. It is fine as long as it is a segment. From the viewpoint of ease of production, physical properties of the solvent-based adhesive composition A, etc., an ABA type triblock copolymer in which the A segment is the above-mentioned high Tg segment and the B segment is the above-mentioned low Tg segment is preferred. In that case, an ABA type triblock copolymer is preferred in which at least one of the two A segments is a high Tg segment and the B segment is a low Tg segment, both of the two A segments are high Tg segments, and the B segment More preferred are ABA-type triblock copolymers in which Tg is a low Tg segment.

As described above, the glass transition temperature (Tg) of the high Tg segment constituting (meth)acrylic block copolymer A is 0° C. or higher and 100° C. or lower. By having the Tg of the high Tg segment within this range, it is easy to control the storage modulus of solvent-based adhesive composition A at room temperature (25°C) to a high level, and it is hard and has excellent processability, as well as in the region exceeding 50°C. There is a tendency for the storage modulus to decrease significantly, resulting in a highly fluid adhesive composition. From the viewpoint of improving the processability of solvent-based 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, even more preferably 8°C or higher, The temperature is even more preferably 10°C or higher, particularly preferably 12°C or higher. On the other hand, from the viewpoint that the storage modulus (G') of the solvent-based adhesive composition A decreases significantly in the region exceeding 50°C and tends to have high fluidity, the Tg of the high Tg segment is set at 90°C or lower. The temperature is preferably 85°C or lower, more preferably 60°C or lower, even more preferably 50°C or lower, and particularly preferably 35°C or lower.

As mentioned above, the Tg of the low Tg segment constituting (meth)acrylic block copolymer A is -100°C or more and less than 0°C. By having the glass Tg of the low Tg segment within this range, only the low Tg segment becomes fluidized at room temperature (25°C), ensuring processability while imparting appropriate adhesive strength to the solvent-based adhesive composition A. There is a tendency for it 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 modulus of the solvent-based adhesive composition A is less likely to decrease at room temperature (25°C) and the processability can be improved. Preferably, −80° C. or higher is more preferable. On the other hand, from the viewpoint of improving the appropriate adhesive strength and processability of the solvent-based adhesive composition A at room temperature (25°C), the Tg of the low Tg segment is preferably -5°C or lower, and more preferably -10°C or lower. The temperature is preferably -20°C or lower, more preferably -30°C or lower, and particularly preferably -40°C or lower.

The difference in Tg between the high Tg segment and 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; The storage modulus at room temperature (25°C) can be easily controlled to be high, and the adhesive composition is hard and has excellent processability, and the storage modulus decreases significantly in the region exceeding 50°C, resulting in a highly fluid adhesive composition. , preferably 30°C or higher, more preferably 35°C or higher, more preferably 40°C or higher, more preferably 45°C or higher, even 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, even more preferably 100°C or lower, particularly preferably 95°C or lower.

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

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 (wt% ), and Tg(1), Tg(2), ...Tg(n) is the glass transition of the homopolymer of monomer component (1), monomer component (2), ... monomer component (n). Represents temperature (unit: absolute temperature: K).
Note that the glass transition temperature of a homopolymer is known from various documents, catalogs, etc., and is described, for example, in J. Brandup, EH Immergut, EA Grulke: Polymer Handbook: JOHNWILEY & SONS, INC. For monomers that do not have numerical values in various literatures, values measured by general thermal analysis, such as differential thermal analysis or dynamic viscoelasticity measurement, can be employed.

The temperature range in which the high-temperature tan δ peak of (meth)acrylic block copolymer A appears is 0° C. or higher (for example, 0° C. or higher and 100° C. or lower), as described above. Since the high temperature region tan δ peak is in this temperature range, the storage modulus of solvent-based adhesive composition A at room temperature (25°C) can be easily controlled to be high, and it is hard and has excellent processability, as well as in the region exceeding 50°C. There is a tendency for the storage modulus to decrease significantly, resulting in a highly fluid adhesive composition. From the viewpoint of improving the processability of solvent-based adhesive composition A at room temperature (25°C), the temperature at which the tan δ peak appears in the high temperature region is preferably 3°C or higher, more preferably 6°C or higher, and even more preferably 9°C or higher. The temperature is preferably 12°C or higher, even more preferably 15°C or higher, and particularly preferably 15°C or higher. On the other hand, from the viewpoint that the storage modulus (G') of solvent-based adhesive composition A is likely to decrease significantly in the region exceeding 50°C and become highly fluid, the temperature at which the tan δ peak appears in the high temperature region is 90°C. The temperature is preferably below, more preferably 80°C or below, even more preferably 70°C or below, even more preferably 65°C or below, and particularly preferably 60°C or below.

The temperature range in which the low-temperature tan δ peak of (meth)acrylic block copolymer A appears is below 0°C (for example, -100°C or higher and below 0°C), as described above. Since the low-temperature region tan δ peak is in this temperature range, only the low Tg segment becomes fluidized at room temperature (25 ° C.), providing appropriate adhesive strength to solvent-based adhesive composition A while ensuring processability. There is a tendency to do so. From the viewpoint that the storage modulus of the solvent-based adhesive composition A is unlikely to decrease at room temperature (25°C) and the processability can be improved, the temperature at which the low-temperature region tan δ peak appears is preferably -95°C or higher, and -90°C. The temperature is more preferably -80°C or higher, even more preferably -70°C or higher. On the other hand, from the viewpoint of improving the appropriate adhesive strength and processability of the solvent-based adhesive composition A at room temperature (25°C), the temperature at which the low-temperature region tan δ peak appears is preferably -5°C or lower, and -10°C or lower. is more preferred, -20°C or lower is even more preferred, -30°C or lower is even more preferred, and -40°C or lower is particularly preferred.

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. It is preferable that the maximum value of the tan δ peak in the high temperature region be within this range, since it is possible to realize excellent processability and shape stability of the (meth)acrylic block copolymer A. 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, from the viewpoint of achieving excellent workability. Further, the maximum value of the tan δ peak in the high temperature region is preferably 2.5 or less, and more preferably 2.2 or less, from the viewpoint that dents are less likely 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. It is preferable that the maximum value of the tan δ peak in the low temperature region be within this range, since it is possible to realize excellent processability and shape stability of the (meth)acrylic block copolymer A. 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, from the viewpoint of achieving excellent workability. Further, the maximum value of the tan δ peak in the low temperature region is preferably 1.5 or less, and more preferably 1 or less, from the viewpoint that dents are less likely to occur.

Note that the above-mentioned high temperature region tan δ peak and low temperature region tan δ peak, as well as the temperature and maximum value at which they appear, are measured by dynamic viscoelasticity measurement.

(Meth)acrylic block copolymer A is composed of multiple segments (including high Tg segments and low Tg segments) obtained by polymerizing monomer components, and the monomer components have (meth)acryloyl groups in the molecule. This includes monomers (acrylic monomers) that have
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 of monomer components (100% by weight). % or more is particularly preferable.

The acrylic monomer constituting (meth)acrylic block copolymer A or each segment thereof (including high Tg segment and low Tg segment) includes an acrylic acid alkyl ester having a linear or branched alkyl group, and Or, it contains a monomer component derived from a methacrylic acid alkyl ester having a linear or branched alkyl group as the main monomer unit with the largest proportion by weight.

As the (meth)acrylic acid alkyl ester having a linear or branched alkyl group to form a segment of the (meth)acrylic block copolymer A, the above-mentioned (meth)acrylic acid having a chain alkyl group is used. Specific examples of alkyl esters are listed. As the (meth)acrylic acid alkyl ester for the segment, one type of (meth)acrylic acid alkyl ester may be used, or two or more types of (meth)acrylic acid alkyl ester 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 acrylate and isononyl acrylate is used.

The segment of the (meth)acrylic block copolymer A may include a monomer unit derived from an alicyclic monomer. Specific examples of the alicyclic monomer for forming the monomer unit of the segment include the above-mentioned (meth)acrylic acid alkyl esters having an alicyclic alkyl group. The alicyclic alkyl group may have a substituent. Examples of the substituent include halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom), straight-chain or branched alkyl groups having 1 to 6 carbon atoms (e.g., methyl group, ethyl group, n-propyl group), group, isopropyl group, etc.). 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 type of alicyclic monomer may be used, or two or more types of alicyclic monomers may be used. The alicyclic monomer for the segment is preferably a cycloaliphatic monomer having 4 to 10 carbon atoms that may have a substituent (e.g., 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)acrylate is used.

The segment of the (meth)acrylic block copolymer A may include a monomer unit derived from a hydroxyl group-containing monomer. A hydroxyl group-containing monomer is a monomer that has at least one hydroxyl group within its monomer unit. When the segment in the (meth)acrylic block copolymer A contains a hydroxyl group-containing monomer unit, adhesiveness and appropriate cohesive force can be easily obtained in the solvent-based pressure-sensitive adhesive composition A.

Specific examples of the hydroxyl group-containing monomer for forming the monomer unit of the segment include the above-mentioned hydroxyl group-containing monomers. 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 ester, more preferably 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, or 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 include a monomer unit derived from a nitrogen atom-containing monomer. A nitrogen atom-containing monomer is a monomer that has at least one nitrogen atom within 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 good hardness and good adhesion reliability in the solvent-based adhesive composition A.

Examples of the nitrogen atom-containing monomer for forming the segment include the above-mentioned nitrogen atom-containing monomers. As the nitrogen atom-containing monomer for the acrylic polymer, one type of nitrogen atom-containing monomer may be used, or two or more types of nitrogen atom-containing monomers may be used. N-vinyl-2-pyrrolidone is preferably used as nitrogen atom-containing monomer for the segment.

The segment of the (meth)acrylic block copolymer A may include a monomer unit derived from a carboxy group-containing monomer. A carboxy group-containing monomer is a monomer that has at least one carboxy group within the monomer unit. When the segment of the (meth)acrylic block copolymer A contains a carboxyl group-containing monomer unit, good adhesion reliability may be obtained in the solvent-based adhesive composition A.

As the carboxy group-containing monomer for forming the monomer unit of the segment, the above-mentioned carboxy group-containing monomers may be mentioned. As the carboxyl group-containing monomer for the segment, one type of carboxyl group-containing monomer may be used, or two or more types of carboxyl group-containing monomers may be used. Acrylic acid is preferably used as the carboxy group-containing monomer for the segment.

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

The monomer component constituting the high Tg segment of the (meth)acrylic block copolymer A is said to be able to easily control the Tg of the high Tg segment within a predetermined range and impart desired physical properties to the (meth)acrylic block copolymer A. From this point of view, (meth)acrylic acid alkyl ester having a linear alkyl group having 1 to 3 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C _1-3 linear alkyl ester") ), (meth)acrylic acid alkyl ester having a branched alkyl group having 3 or 4 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C _3-4 branched alkyl ester") and alicyclic monomers. Since homopolymers of these monomers have a relatively high Tg, by including a monomer selected from these as a monomer component constituting the high Tg segment, it is easy to control the Tg of the high Tg segment within the predetermined range of the present invention.

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

When a high Tg segment contains an alicyclic monomer as a monomer component, the content of the alicyclic monomer relative to the total amount of monomer components (100% by weight) can easily 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 even 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, and more. The content is preferably 80% by weight or more, more preferably 90% by weight or more, 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 alkyl ester, acrylic acid C _3-4 branched alkyl ester is preferable, and t-butyl acrylate (Tg of homopolymer: 35° C.) is particularly preferable.

When the high Tg segment contains (meth)acrylic acid C _1-3 linear alkyl ester and/or (meth)acrylic acid C _3-4 branched alkyl ester as a monomer component, (meth)acrylic acid The content of C _1-3 linear alkyl ester and/or (meth)acrylic acid C _3-4 branched alkyl ester with respect to the total amount of monomer components (100% by weight) is such that the Tg of the high Tg segment is within a predetermined range. From the viewpoint of easy 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, particularly preferably 95% by weight or more.

The monomer component constituting the low Tg segment of the (meth)acrylic block copolymer A is said to be able to easily control the Tg of the low Tg segment within a predetermined range and impart desired physical properties to the (meth)acrylic block copolymer A. From this point of view, (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C _4-18 alkyl ester") ) and a hydroxyl group-containing monomer. That is, since the homopolymer of (meth)acrylic acid C _4-18 alkyl ester has a relatively low Tg, by including it as a monomer component constituting the low Tg segment, the Tg of the low Tg segment can be adjusted to the specified value in the present invention. Easy to control within the range. On the other hand, the hydroxyl group-containing monomer also has a relatively low Tg, and furthermore, the (meth)acrylic block copolymer A can easily obtain adhesive properties and appropriate cohesive force. Therefore, it is more preferable that the monomer component constituting the low Tg segment of the (meth)acrylic block copolymer A contains both a (meth)acrylic acid C _4-18 alkyl ester and a hydroxyl group-containing monomer.

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), 2-ethylhexyl acrylate (Tg of homopolymer: -55°C), : -70℃), n-hexyl acrylate (Tg of homopolymer: -57℃), n-octyl acrylate (Tg of homopolymer: -65℃), isononyl acrylate (Tg of homopolymer: -58℃) ) is particularly preferred.

When a (meth)acrylic acid C _4-18 alkyl ester is contained as a 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 of monomer components (100% by weight) is: From the viewpoint of easily controlling the Tg of the low Tg segment within a predetermined range and imparting desired physical properties to the (meth)acrylic block copolymer A, preferably 10% by weight or more (for example, 10 to 100% by weight), more 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 The content is 70% by weight or more, more preferably 80% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more.

The hydroxyl group-containing monomer is preferably a hydroxyl group-containing (meth)acrylic acid alkyl ester, such as 4-hydroxybutyl acrylate (Tg of homopolymer: -65°C), 2-hydroxyethyl acrylate (Tg of homopolymer: -15 °C) is particularly preferred.

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

When the monomer component constituting the low Tg segment of (meth)acrylic block copolymer A contains both a (meth)acrylic acid C _4-18 alkyl ester and a hydroxyl group-containing monomer, the hydroxyl group-containing monomer and (meth)acrylic acid The ratio of C _4-18 alkyl ester (hydroxyl group-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, further 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.

(Meth)acrylic block copolymer A can be produced by the above-mentioned living radical polymerization method of monomer components. Living radical polymerization maintains the simplicity and versatility of conventional radical polymerization, while preventing termination reactions and chain transfer and allowing growth without deactivation of growing terminals, allowing precise control and uniformity of molecular weight distribution. This is preferable because it is easy to produce a polymer having a specific 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 to the high Tg segment; the low Tg segment may be produced first and the monomer of the high Tg segment may be polymerized.

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

For the living radical polymerization method, any known method can be used without particular limitation, and depending on the method of stabilizing the polymer growth terminal, there may be a method using a transition metal catalyst (ATRP method); a sulfur-based reversible addition method; There are methods such as a method using a cleavage chain transfer agent (RAFT agent) (RAFT method) and a method using an organic tellurium compound (TERP method). Among these methods, it is preferable to use the RAFT method from the viewpoints of diversity of usable monomers, ease of molecular weight control, and no metal remaining in the solvent-based adhesive composition.

For the RAFT method, any known method can be used without particular limitation. For example, step 1 (first RAFT polymerization ), and Step 2 (Step 2) in which a monomer component different from the monomer composition in Step 1 is further added and polymerized to the first segment obtained in Step 1 to add the second segment to the first segment. 2 RAFT polymerization). After the second RAFT polymerization, third, fourth, etc. RAFT polymerizations may be performed in the same manner as the second RAFT polymerization, and third, fourth, etc. segments may be further added.

The steps 1 and 2 can be carried out by a known and commonly used method, such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method using heat or active energy ray irradiation (thermal polymerization method, active energy ray polymerization). method), etc. Among these, the solution polymerization method is preferred in terms of transparency, water resistance, cost, and the like. Note that the polymerization is preferably carried out while avoiding contact with oxygen in order to suppress polymerization inhibition caused by oxygen. For example, it is preferable to carry out the polymerization under a nitrogen atmosphere.

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

As the RAFT agent, known agents can be used without particular limitation, such as compounds represented by the following formula (1), formula (2), or formula (3) (trithiocarbonate, dithioester, dithiocarbonates) are preferred.

In formula (1), formula (2), or formula (3) [formulas (1) to (3)], R ^1a and R ^1b are the same or different and represent a hydrogen atom, a hydrocarbon group, or a cyano group. 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 (linear, branched, or cyclic saturated or unsaturated hydrocarbon groups, etc.). Among them, hydrocarbon groups having 1 to 12 carbon atoms 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, etc. Straight chain, branched, or cyclic alkyl group having 1 to 12 carbon atoms; Aryl group having 6 to 12 carbon atoms such as phenyl group; Aryl alkyl group having 7 to 10 total carbon atoms such as benzyl group and 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 of the 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 some of the hydrogen atoms of the hydrocarbon group are substituted with carboxyl groups (eg, carboxyalkyl group). Examples of the above-mentioned hydrocarbon groups include hydrocarbon groups having 1 to 20 carbon atoms (straight chain, branched chain, or cyclic saturated or unsaturated hydrocarbon groups, etc.), and among them, carbon atoms 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, etc. Straight chain, branched, or cyclic alkyl groups having 1 to 12 carbon atoms; arylalkyl groups having 7 to 10 total carbon atoms such as benzyl group and phenethyl group; and the like.

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

Many of the above RAFT agents are commercially available. Those that are not commercially available can be easily synthesized by known or conventional methods. In addition, in this invention, RAFT agent can also be used individually by 1 type, and can also be used in combination of 2 or more types.

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

The step 1 can be performed by polymerizing monomer components in the presence of a RAFT agent. In step 1, the amount of the RAFT agent used 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 monomer components. With such an amount used, it is easy to control the reaction, and it is also easy to control the weight average molecular weight of the obtained segment.
The step 2 can be carried out 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 include peroxides and azo compounds. Among these, azo compounds are preferred. One kind of polymerization initiator can be used alone or two or more kinds can be used.

Examples of peroxide-based polymerization initiators include benzoyl peroxide and tert-butyl permaleate.
Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 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'-dimethyleneisobutyramidine), 2,2'-azobis(isobutyramide) dihydrate, 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobis(2-cyanopropanol), Examples 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 monomer components. With such a usage amount, it is easy to control the weight average molecular weight of the obtained segment.

Although the RAFT method may be bulk polymerization without using a polymerization solvent, 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 cyclopentane; 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 , phenylethyl ether, diphenyl ether; esters such as ethyl acetate, propyl acetate, butyl acetate, methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone; N,N-dimethylformamide, N , N-dimethylacetamide, and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; and sulfoxides such as dimethyl sulfoxide and sulfolane. The polymerization solvent can be used alone or in combination of two or more.

The amount of the polymerization solvent used is not particularly limited, and for example, it is preferably 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 per 1 g of monomer component. It is preferably 1 mL or less, 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 under an inert gas atmosphere such as nitrogen gas. This reaction can be carried out under normal pressure, increased pressure or reduced pressure, and is usually carried out under normal pressure. Further, 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 the completion of the polymerization reaction, the solvent used, residual monomers, etc. are removed from the resulting reaction mixture by ordinary separation and purification means, and the desired (meth)acrylic block copolymer A can be separated.

When preparing the high Tg segment or low Tg segment of the (meth)acrylic block copolymer A in step 1, the weight average molecular weight (Mw) of the high Tg segment or low Tg segment is not particularly limited, but is preferably 10 ,000 to 1,000,000, more preferably 50,000 to 500,000, still more preferably 100,000 to 300,000. It is suitable for the Mw of the high Tg segment or the low Tg segment to be within this range for the effects of the present invention described above.
When the (meth)acrylic block copolymer A has two or more high Tg segments or low Tg segments, the above Mw is the sum of the two or more high Tg segments or low Tg segments.

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, even more preferably is 400,000 to 2,500,000. It is suitable for the Mw of the (meth)acrylic block copolymer A to be within this range for the above-mentioned effects of the present invention.

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, particularly preferably 2. It is 5 or more, preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less, particularly preferably 3.5 or less.

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

The content of high Tg segments in the (meth)acrylic block copolymer A is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably The content is 25% by weight or more, particularly preferably 30% by weight or more, and 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, and even more preferably The content is 15% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, even more preferably 40% by weight or less, particularly preferably 30% by weight or less.

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

The content of (meth)acrylic block copolymer A in solvent-based pressure-sensitive adhesive composition A is not particularly limited, but has excellent processability at room temperature (25°C) and excellent level difference absorption in a region exceeding 50°C. From the viewpoint of obtaining the desired amount, it 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-based adhesive composition A. The content is more preferably 80% by weight or more, particularly preferably 90% by weight or more.

(solvent)
Since the polymer in the third form is a solid, the solvent-based 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 monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene, etc. are generally used as the solvent. The solution concentration is usually about 20 to 80% by weight.

Polymerization initiators for solution polymerization of monomer components include azo initiators, peroxide initiators, and redox initiators that combine peroxides and reducing agents (for example, persulfate and sodium bisulfite). (a combination of peroxide and sodium ascorbate) are preferably used. The amount of the polymerization initiator used is not particularly limited, but for example, it 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 monomer components forming the polymer. preferable.

(colorant)
The solvent-based adhesive composition used to form the third type of 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 solvent-based adhesive composition. Dyes are preferred because they can achieve low haze even when added in small amounts, and are easy to distribute uniformly without settling unlike pigments. Pigments are also preferred because they provide high color development even when added in small amounts. If a pigment is used as a coloring agent, it is preferably one with low or no electrical conductivity. Moreover, when using a dye, it is preferable to use it together with an antioxidant or the like.

In the third embodiment, the colorant contained in the solvent-based pressure-sensitive adhesive composition includes, in addition to the ultraviolet-transparent colorant described above for the first embodiment, an ultraviolet-absorbing colorant.

Examples of ultraviolet-transparent black pigments 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 Industry Co., Ltd. Examples of ultraviolet absorbing black pigments include carbon black and titanium black.

The content of the colorant in the solvent-based adhesive composition is, for example, about 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of monomers, and depends on the type of colorant, the color tone of the adhesive layer, and the light transmission. It may be set as appropriate depending on the rate, etc. The colorant may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

(Crosslinking agent)
The solvent-based pressure-sensitive adhesive composition of the third form may contain a crosslinking agent capable of crosslinking with the above-mentioned polymer. Note that when the solvent-based adhesive composition contains a (meth)acrylic block copolymer, the third form of the adhesive layer has sufficient shape stability and therefore does not need to contain a crosslinking agent.

When the solvent-based adhesive composition contains a crosslinking agent in the third embodiment, the crosslinking agent is the same as that described above for the second embodiment, and isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferable.

In the third embodiment, when the solvent-based adhesive composition contains a crosslinking agent, the content thereof is about 0.01 to 5 parts by weight, 0.05 parts by weight or more, and 0.05 parts by weight or more, based on 100 parts by weight of the polymer. The amount 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-mentioned components, the third form of the solvent-based adhesive composition contains oligomers, tackifiers, silane coupling agents, chain transfer agents, plasticizers, softeners, deterioration inhibitors, fillers, antioxidants, It may also contain surfactants, antistatic agents, and the like.

<Optical laminate>
In this embodiment, the optical laminate 10 or 11 can be prepared by laminating the adhesive layer 2 on the surface 1b of the base material 1 that has not been subjected to anti-reflection treatment and/or anti-glare treatment.

[First form]
The method for laminating the adhesive layer of the first form on the surface 1b is not particularly limited, and for example, the photocurable adhesive composition of the first form is applied onto a release film, formed into a sheet, and then exposed to light. This can be done by curing to produce a sheet-like adhesive layer and then bonding it onto the surface 1b of the base material 1.

The photocurable adhesive composition of the first form is applied in the form of a sheet (layer) on a release film, and the coating film of the photocurable adhesive composition on the release film is irradiated with ultraviolet rays to perform photocuring. As a result, a pressure-sensitive adhesive layer of the first form is obtained. When performing photocuring, a release film is further attached to the surface of the coating film, and the photocurable adhesive composition is sandwiched between the two release films and irradiated with ultraviolet rays to prevent polymerization inhibition caused by oxygen. It is preferable to prevent this. Before photocuring, the sheet-like coating film may be heated for the purpose of removing the solvent or dispersion medium of the colorant. When removing the solvent and the like by heating, it is preferable to remove the solvent before attaching the release film.

Films made of various resin materials are used as the film base material of the release film. Examples of 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, (meth)acrylic resins, Examples include polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin, and the like. Among these, polyester resins such as polyethylene terephthalate are particularly preferred. The thickness of the film base material is preferably 10 to 200 μm, more preferably 25 to 150 μm. Examples of the material for the mold release layer include silicone mold release agents, fluorine mold release agents, long chain alkyl mold release agents, fatty acid amide mold release agents, and the like. The thickness of the release layer is generally about 10 to 2000 nm.

Methods for applying the photocurable adhesive composition onto the release film include roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, and air knife coating. Various methods such as , curtain coat, lip coat, and die coater are used.

The thickness of the adhesive layer containing the colorant is not particularly limited, and should be appropriately set to be equal to or higher than the height of the light emitting elements arranged on the display panel, which will be described later, so as to be able to sufficiently seal the light emitting elements arranged on the display panel. Bye. For example, the thickness of the adhesive layer containing the colorant is 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2.0 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 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 mentioned above, since the colorant has UV transmittance, it is possible to photocure the photocurable adhesive composition uniformly in the thickness direction even when the adhesive layer is thick. . The thickness of the 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 adhesive composition coated in a layer on a release film with ultraviolet rays, active species are generated from the photopolymerization initiator, the photopolymerizable compound is polymerized, and the polymerization rate increases (unreacted As the amount of monomer decreases, the liquid photocurable adhesive composition becomes a solid (standard shape) adhesive layer. The light source for ultraviolet irradiation is not particularly limited as long as it can irradiate light in the wavelength range to which the photopolymerization initiator contained in the adhesive composition is sensitive, and includes LED light sources, high-pressure mercury lamps, and ultra-high-pressure mercury lamps. Lamps, metal halide lamps, xenon lamps, etc. are used.

The cumulative amount of irradiation light is, for example, about 100 to 5000 mJ/cm ² . The polymerization rate (nonvolatile content) of the adhesive layer made of the photocured product of the photocurable adhesive composition is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The polymerization rate may be 93% or more or 95% or more. In order to reduce the nonvolatile content, the adhesive layer may be heated to remove volatile content such as residual monomers, unreacted polymerization initiators, and solvents.

When release films are provided on both sides of the 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 a release film temporarily attached to one side from the adhesive layer and the peeling force when peeling the release film temporarily attached to the other side from the adhesive layer may be the same or different. You can. If the peeling forces of the two are different, the first form can be obtained by peeling off the release film (light release film) with a relatively small peeling force from the adhesive layer first and then bonding it to the surface 1b of the base material 1. An optical laminate having a pressure-sensitive adhesive layer can be produced.

The method is the same as above except that the photocurable adhesive composition is applied to the surface 1b of the substrate 1 and formed into a sheet, followed by attaching a release film to the surface of the coating film and irradiating it with ultraviolet rays. It is also possible to produce an optical laminate having the adhesive layer of the first form.

The adhesive layer containing the colorant absorbs 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 % or less.

In the first embodiment, as described above, a coloring agent that absorbs ultraviolet light less than visible light is used. Therefore, in the adhesive layer, the average transmittance T _UV in the wavelength range of 330 to 400 nm is larger than the average transmittance T _VIS in the wavelength range of 400 to 700 nm. The average transmittance T _VIS of the 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. The average transmittance T _UV of the adhesive layer at a wavelength of 330 to 400 nm is preferably 5% or more, and may be 10% or more, 15% or more, 20% or more, or 25% or more. The difference T _UV -T _VIS between T _UV and T _VIS may be 3% or more, 5% or more, 8% or more, or 10% or more.

In the first form, the shear storage modulus G'25°C of the adhesive layer at a temperature of 25°C 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 modulus G'85° C. of the adhesive layer at a temperature of 85° C. is, for example, about 3 to 300 kPa, and may be 5 kPa or more, 7 kPa or more, or 10 kPa or more, and 200 kPa or less, 150 kPa or less, or 100 kPa. It may be the following. If the shear storage modulus of the adhesive layer is within the above range, appropriate flexibility and adhesiveness can be achieved at the same time. The shear storage modulus is a value measured by dynamic viscoelasticity measurement at a frequency of 1 Hz.

[Second form]
The optical laminate having the adhesive layer of the second form is prepared by coating the curable adhesive composition of the second form on a release film, drying and removing the solvent as necessary, and then applying the curable adhesive composition of the second form to the surface 1b of the base material 1. It can be prepared by laminating with. Further, the optical laminate having the adhesive layer of the second form can be prepared by applying the curable adhesive composition of the second form onto the surface 1b of the base material 1, and drying and removing the solvent as necessary. can also be prepared.

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

After applying the photocurable adhesive composition, a crosslinked structure is introduced into the polymer by heating if necessary. The heating temperature and heating time may be appropriately set depending on the type of crosslinking 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. Introduction of the crosslinked structure does not necessarily need to involve heating.

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

The optical laminate having the photocurable adhesive layer of the second form can be photocured by irradiating it with ultraviolet rays after being bonded to a display panel described below. 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 is highly flexible, it can fill in uneven shapes and steps formed by light-emitting elements arranged on the display panel, and after photo-curing, the adhesive layer has strong adhesion to the display panel. and improve adhesion reliability.

Ultraviolet rays are used as actinic rays for photocuring the adhesive layer of the second form. Similar to the adhesive layer of the first embodiment, the colorant has a higher transmittance for ultraviolet light than visible light, so even if the adhesive layer is thick, curing inhibition during photocuring can be suppressed.

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

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

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

It is preferable that the adhesive layer of the third form has the same thickness, light transmittance, and shear storage modulus as the adhesive layer of the first form.

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

When the solvent-based adhesive composition contains (meth)acrylic block copolymer A, the storage modulus (G'50) at 50°C of the adhesive layer is not particularly limited, but the level difference absorption in the region exceeding 50°C From the viewpoint of improving the From the viewpoint of improving handling properties in areas exceeding be.

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

The storage modulus (G'25) at 25°C, the storage modulus (G'25) at 50°C, and their ratio (G'25/G'50) are measured by dynamic viscoelasticity measurement. It is something that will be done.

An optical laminate having an adhesive layer containing a colorant absorbs visible light. The optical laminate of this embodiment preferably has a maximum value of transmittance between 350 nm and 450 nm.

The total light transmittance of the optical laminate of this 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 % or less.

In the optical laminate of this embodiment, a release film may be provided on the adhesive layer until use. Further, in the optical laminate of this embodiment, a surface protection film may be laminated on the surface 1a of the base material 1 that has been subjected to antireflection treatment and/or antiglare treatment. Formation of a surface protection film is suitable for preventing scratches and dirt from adhering to the optical laminate and optical products including the optical laminate during manufacture, transportation, and shipping.

In addition to the base material 1, the adhesive layer 2, the release film, and the surface protection film, the optical laminate of this embodiment may include other layers, such as base materials other than the base material 1, to the extent that the effects of the present invention are not impaired. It may have a material, an adhesive layer other than the adhesive layer 2, an intermediate layer, an undercoat layer, etc. on the surface or between arbitrary layers.

<Self-luminous display device>
A self-luminous display device according to a second aspect of the present invention is provided by arranging a small number of light-emitting elements on a wiring board and selectively causing each light-emitting element to emit light by a light-emission control means connected thereto. This is a display device that can directly display visual information such as characters, images, and moving images on a display screen by blinking each light emitting element. Examples of self-luminous display devices include mini/micro LED display devices and organic EL (electroluminescence) display devices. The optical laminate according to the first aspect of the present invention is particularly suitable for manufacturing mini/micro LED display devices.

FIG. 3 is a schematic diagram (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 aspect of the present invention. The surface on which the LED chips 6 are arranged on the display panel and the adhesive layer 2 of the optical laminate 10 are laminated.

In this embodiment, a metal wiring layer 5 for sending light emission control signals to each LED chip 6 is laminated on the substrate 4 of the display panel. LED chips 6 that emit light in each color of red (R), green (G), and blue (B) are alternately arranged on the substrate 4 of the display panel with metal wiring layers 5 interposed therebetween. The metal wiring layer 5 is made of metal such as copper, and reflects the light emitted from each LED chip 6, reducing the visibility of the image. Moreover, the light emitted by each LED chip 6 of each color of RGB is mixed, resulting in a decrease in contrast.

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

As described above, in the optical laminate according to this embodiment, since the adhesive layer contains a colorant, even when a metal adherend is laminated on the adhesive layer, reflection and gloss of the metal surface are not affected. It can be prevented. When a metal adherend is laminated on the adhesive layer of the optical laminate of this embodiment, the reflectance of the base material surface 1a in the visible light region of 5° specular reflection is preferably 50% or less, and 30% or less. % or less, even more preferably 15% or less, particularly preferably 10% or less. When a metal adherend is laminated on the adhesive layer of the optical laminate of this embodiment, the glossiness (based on JIS Z 8741-1997) of the base material surface 1a is preferably 100% or less, and preferably 80%. It is more preferably at most 60%, even more preferably at most 50%.
Note that copper, aluminum, stainless steel, etc. can be used as the metal adherend.

Furthermore, in the mini/micro LED display device of this embodiment, the surface 1a of the base material 1 is subjected to anti-reflection treatment and/or anti-glare treatment 3, which prevents reflection of external light and image reflection on the surface 1a of the base material. Decrease in visibility due to crowding etc. is prevented, or appearance such as glossiness is adjusted. FIG. 4 is a schematic diagram (cross-sectional view) showing another 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 21 according to this embodiment is the same as that shown in FIG. 3 except that an 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 this embodiment is the same as described above.

The self-luminous display device of this embodiment may include optical members other than the display panel and the optical laminate. Examples of the optical member include, but are not particularly limited to, a polarizing plate, a retardation plate, an antireflection film, a viewing angle adjustment film, an optical compensation film, and the like. Note that optical members also include members (design films, decorative films, surface protection plates, etc.) that play a role of decoration and protection while maintaining the visibility of display devices and input devices.

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

Specifically, the display panel and the optical laminate having the adhesive layer of the first embodiment can be attached by laminating them under heat and/or pressure. When an optical laminate having a display panel and an adhesive layer of the second embodiment is attached, it can be carried out by laminating them under heat and/or pressure and then photocuring. Photocuring can be performed in the same manner as the photocuring for forming the adhesive layer of the first embodiment described above.

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

The present invention will be explained in more detail below based on Examples, but the present invention is not limited to these Examples. In addition, 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. was attached to the surface of the anti-glare film on which the anti-glare layer was not formed using an adhesive, and a high-precision micro-shape measuring device (product name: Surfcoder ET4000) was used. , manufactured by Kosaka Institute Co., Ltd.), the surface shape of the anti-glare layer was measured under the condition of a cutoff value of 0.8 mm, and the average inclination angle θa was determined. Note that the high-precision fine shape measuring device automatically calculates the average inclination angle θa. The average inclination angle θa is based on JIS B 0601 (1994 edition).

(Haze)
According to the method specified in JIS 7136, a haze meter (manufactured by Murakami Color Science Institute, trade name "HN-150") was installed so that light was incident on 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 included 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) were used as light-diffusing fine particles per 100 parts by weight of the resin solid content of the resin. 14 parts by weight of synthetic smectite (manufactured by Kunimine Kogyo Co., Ltd., trade name "Smecton SAN"), which is an organic clay, as a thixotropy imparting agent, and a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907"). '') and 0.5 parts by weight of a leveling agent (manufactured by DIC Corporation, trade name ``Megafac F-556'', solid content 100%) were mixed. This mixture was diluted with a toluene/ethyl acetate mixed solvent (weight ratio 90/10) so that the solid content concentration was 30% by weight to prepare a light diffusing element forming material (coating liquid).
Applying an anti-glare layer forming material (coating liquid) using a bar coater to one side of a triacetyl cellulose (TAC) film (manufactured by Fuji Film Corporation, product name "TG60UL", thickness: 60 μm) that can function as a protective layer, A coating film was formed. The transparent TAC film base material on which this coating film was formed was then conveyed to a drying process. In the drying step, the coating film was dried by heating at 110° C. for 1 minute. Thereafter, the coating film was cured by irradiating ultraviolet rays with a cumulative light intensity of 300 mJ/cm ² using a high-pressure mercury lamp, and a light diffusing element with a thickness of 5.0 μm was formed on one side of the TAC film to obtain anti-glare film 1. Ta. The haze value of anti-glare film 1 was 42%. The anti-glare layer of anti-glare film 1 had an θa (°) of 1.22.

Manufacturing example 2
(Preparation of anti-glare film)
14 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical Co., Ltd., trade name "Silohobic 100", weight average particle size: 2.6 μm) was added as light-diffusing fine particles, and the thickness after curing treatment was 7.5 μm. 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 0 μm. The haze value of anti-glare film 2 was 11%. The anti-glare layer of anti-glare film 2 had an θa (°) of 1.43.

Manufacturing example 3
(Preparation of anti-glare film)
As a resin included 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. Per 100 parts by weight of resin solid content of the resin, 7 parts by weight of amorphous silica (manufactured by Fuji Silysia Co., Ltd., trade name "Silohobic 702") as anti-glare layer forming particles, 6.5 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD184"), 5 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD184"), a leveling agent (manufactured by DIC Corporation, trade name) 0.5 part by weight of "Megafac F-556") was mixed. This mixture was diluted with toluene so that the solid content concentration was 30% to prepare an anti-glare layer forming material (coating liquid).
A transparent plastic film base material (TAC film, manufactured by Fuji Film Co., Ltd., trade name "TD80UL", thickness: 80 μm) was prepared as a translucent base material. A coating film was formed on one side of the transparent plastic film substrate using the anti-glare layer forming material (coating liquid) using a bar coater. The transparent plastic film base material on which this coating film was formed was then transported to a drying process. In the drying step, the coating film was dried by heating at 110° C. for 1 minute. Thereafter, the coating film was cured by irradiating ultraviolet rays with a cumulative light intensity of 300 mJ/cm ² using a high-pressure mercury lamp to form an anti-glare layer with a thickness of 5.0 μm, thereby obtaining an anti-glare film 3. The anti-glare layer of anti-glare film 3 had an θa (°) of 3.5.

Production example 4
(Preparation of anti-glare film)
As anti-glare layer forming particles, 6.5 parts by weight of amorphous silica (manufactured by Fuji Silicia Co., Ltd., trade name "Cylohobic 702"), 200") was added, 2.5 parts by weight of a thickener (manufactured by Co-op Chemical, trade name "Lucentite SAN") was added, and the thickness after hardening treatment was 8.0 μm. An anti-glare film 4 was obtained in the same manner as in Production Example 3. The anti-glare layer of anti-glare film 4 had an θa (°) of 2.3.

Manufacturing example 5
(Preparation of prepolymer)
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube, 67 parts by weight of butyl acrylate (BA) and 14 parts by weight of cyclohexyl acrylate (CHA, manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #155") were added. parts by weight, 19 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.09 parts by weight of photopolymerization initiator (manufactured by BASF, trade name "Irgacure 184"), and photopolymerization initiator (manufactured by BASF, product name) After adding 0.09 parts by weight (named "Irgacure 651"), nitrogen gas was passed through the solution, and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, polymerization was performed by irradiating UVA at 5 mW/cm ² and the reaction rate was adjusted to 5 to 15% to obtain an acrylic prepolymer solution.

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

Manufacturing example 7
(Preparation of adhesive composition)
To the acrylic prepolymer solution obtained in Production Example 7 (total prepolymer amount is 100 parts by weight), 9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added. , 0.12 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin Nakamura Industrial Chemical Co., Ltd., 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 adhesive composition solution.

Production example 8
(Preparation of adhesive sheet)
The black adhesive composition solution prepared in Production Example 6 was cured on the release surface of a 38 μm thick release film R1 (manufactured by Mitsubishi Plastics Co., Ltd., trade name "MRF#38"), in which one side of the polyester film is the release surface. The film was coated to a final thickness of 100 μm, and a release film R2 (manufactured by Mitsubishi Plastics Co., Ltd., MRE #38) having one side of the polyester film as a release surface was covered to block air. One side of this laminate was irradiated with ultraviolet rays using a black light (manufactured by Toshiba Corporation, trade name "FL15BL") under conditions of an illuminance of 5 mW/cm ² and an integrated light amount of 1300 mJ/cm ² . Thereby, a 100 μm thick adhesive sheet 1 in which a photocrosslinkable adhesive, which is a cured product of the black adhesive composition, was sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less adhesive sheet.
Note that the value of the illuminance 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) with a peak sensitivity wavelength of about 350 nm.

Production example 9
(Preparation of adhesive sheet)
A photocrosslinkable adhesive, which is a cured product of the black adhesive composition, was sandwiched between 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. An adhesive sheet 2 having a thickness of 50 μm was obtained in the form of a substrate-less adhesive sheet.

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

Examples 1 to 4
(Preparation of optical laminate)
Peel off one of the release films from the adhesive sheet 1 obtained in Production Example 10, and apply the exposed adhesive surface to the surface of the anti-glare films 1 to 4 obtained in Production Examples 1 to 4 on which the anti-glare layer is not formed. By laminating them together, optical laminates each consisting of anti-glare films 1 to 4/adhesive sheet 1/release film were obtained.

Examples 5-8
(Preparation of optical laminate)
Optical laminates each consisting of anti-glare films 1 to 4/adhesive sheet 2/release film were obtained in the same manner as Examples 1 to 4, except that adhesive sheet 2 obtained in Production Example 9 was used.

Comparative examples 1 to 4
(Preparation of optical laminate)
Optical laminates each consisting of anti-glare films 1 to 4/adhesive sheet 3/release film were obtained in the same manner as in Examples 1 to 6, except that adhesive sheet 3 obtained in Production Example 10 was used.

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

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

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

(evaluation)
Transmittance, reflectance, and gloss 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 enters a spectrophotometer U4100 (manufactured by Hitachi High-Technologies) from the anti-glare film/TAC film side. The transmittance (%) in the visible light region was measured. This transmittance is a Y value measured using a 2-degree field of view (C light source) according to JIS Z8701 and subjected to visibility correction.

(2) Reflectance/Gloss A plate was prepared by laminating aluminum foil on a black acrylic plate. 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 in a spectrophotometer U4100 (manufactured by Hitachi High-Technologies Corporation) with an anti-glare film/TAC film placed 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 placed in a gloss meter (manufactured by Murakami Color Chemistry Institute, trade name: "GM-26 PRO") using the method specified in JIS Z8741-1997, with the anti-glare film/TAC film facing the light source. 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 comprising a base material and an adhesive layer containing a colorant,
The base material is anti-reflection treated and/or anti-glare treated on one side,
The adhesive layer is laminated on the side of the base material that is not subjected to the anti-reflection treatment and/or the anti-glare treatment,
The adhesive layer is an adhesive layer formed from a photocurable adhesive composition containing a polymer, a photopolymerizable compound, a photoinitiator, and a colorant,
The colorant is an optical laminate in which the average transmittance in the wavelength range of 330 to 400 nm is higher than the average transmittance in the wavelength range of 400 to 700 nm . The optical system according to claim 1, wherein the colorant is an ultraviolet-transparent black pigment that absorbs ultraviolet light less than visible light, or an ultraviolet-transparent black dye that absorbs ultraviolet light less than visible light. laminate. The optical laminate according to claim 1 , wherein the content of the colorant in the photocurable adhesive composition is 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of monomers. The optical laminate according to any one of claims 1 to 3 , wherein the photopolymerization initiator has at least one absorption maximum in a wavelength range of 330 to 400 nm. The optical laminate according to any one of claims 1 to 4, wherein the polymer is an acrylic polymer. The optical laminate according to any one of claims 1 to 5, wherein the polymer has a glass transition temperature of 0° C. or lower. The optical laminate according to any one of claims 1 to 6, wherein the photocurable adhesive composition further contains a crosslinking agent capable of crosslinking with the polymer. The optical laminate according to any one of claims 1 to 7, wherein the optical laminate has a maximum value of transmittance in a range of 350 nm to 450 nm. The optical laminate according to any one of claims 1 to 8, wherein the adhesive layer has a total light transmittance of 80% or less. The optical laminate according to any one of claims 1 to 9, wherein the adhesive layer has a thickness of 10 to 500 μm. The optical laminate according to any one of claims 1 to 10, wherein the adhesive layer has a shear storage modulus of 10 to 1000 kPa at a temperature of 25°C. The optical laminate according to any one of claims 1 to 11, wherein the adhesive layer has a shear storage modulus of 3 to 300 kPa at a temperature of 85°C. The optical laminate according to claim 1, 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 agent,
The optical laminate according to claim 13, wherein the anti-glare layer has an agglomerated portion where the particles and the thixotropy imparting agent aggregate to form a convex portion on the surface of the anti-glare layer. The optical laminate according to claim 14, wherein the average inclination angle θa (°) of the convex portion on the surface of the anti-glare layer is in the range of 0.1 to 5.0. The optical laminate according to any one of claims 1 to 15, further comprising a surface protection film laminated on the antireflection-treated and/or anti-glare-treated surface of the base material. A display panel with multiple light emitting elements arranged on one side of a substrate,
A self-luminous display device comprising the optical laminate according to any one of claims 1 to 16,
A self-luminous display device, wherein a surface of the display panel on which light emitting elements 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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