CN115362235A - Optical laminate - Google Patents

Optical laminate Download PDF

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Publication number
CN115362235A
CN115362235A CN202180026276.5A CN202180026276A CN115362235A CN 115362235 A CN115362235 A CN 115362235A CN 202180026276 A CN202180026276 A CN 202180026276A CN 115362235 A CN115362235 A CN 115362235A
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CN
China
Prior art keywords
adhesive layer
meth
pressure
sensitive adhesive
weight
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Pending
Application number
CN202180026276.5A
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Chinese (zh)
Inventor
浅井量子
家原惠太
真田加纱音
仲野武史
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Nitto Denko Corp
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Nitto Denko Corp
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Priority to CN202311331023.6A priority Critical patent/CN117551396A/en
Publication of CN115362235A publication Critical patent/CN115362235A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/30—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/006—Anti-reflective coatings
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/04—Thixotropic paints
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/29—Laminated material
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
    • H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/58—Optical field-shaping elements
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/318—Applications of adhesives in processes or use of adhesives in the form of films or foils for the production of liquid crystal displays
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/122—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/20—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive itself
    • C09J2301/208—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive itself the adhesive layer being constituted by at least two or more adjacent or superposed adhesive layers, e.g. multilayer adhesive
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Optics & Photonics (AREA)
  • Wood Science & Technology (AREA)
  • Materials Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Theoretical Computer Science (AREA)
  • Laminated Bodies (AREA)
  • Electroluminescent Light Sources (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

The invention aims to provide an optical laminate suitable for manufacturing a self-luminous display device such as a Mini/Micro LED display device which improves the light emitting efficiency and the anti-reflection function and contrast of metal wiring. The present invention also aims to reduce the number of steps and necessary members in the manufacturing process of the self-luminous display device. The optical laminate (10) has a laminated structure in which a first pressure-sensitive adhesive layer (1), a second pressure-sensitive adhesive layer (2), and a base material (3) are laminated in this order. Visible light transmittance T of the first adhesive layer (1) 1 And the visible light transmittance T of the second adhesive layer (2) 2 Satisfy T 1 <T 2 . Preferably, the first adhesive layer (1) has a visible light transmittance T 1 And the visible light transmittance T of the base material (3) 3 Satisfy T 1 <T 3 。

Description

Optical laminate
Technical Field
The present invention relates to an optical laminate suitable for encapsulating a light emitting element of a self-light emitting display device such as a Mini/Micro LED.
Background
In recent years, as a next-generation Display device, a self-Light Emitting Display device represented by a Mini/Micro LED Display device (Mini/Micro Light Emitting Diode Display device) has been designed. A Mini/Micro LED display device uses, as a basic configuration, a substrate on which a plurality of Micro LED light emitting elements (LED chips) are arrayed at high density as a display panel, the LED chips are sealed with a sealing material, and a covering member such as a resin film or a glass plate is laminated on the outermost layer.
Self-luminous display devices such as Mini/Micro LED display devices include several types such as a white backlight type, a white light emission color filter type, and an RGB type, and in the white light emission color filter type and the RGB type, a black sealing material is sometimes used in order to prevent reflection of metal wiring, metal oxide such as ITO, and the like disposed on a substrate of a display panel (see, for example, patent documents 1 to 3). In the RGB Mini/Micro LED display device in which the LED chips are arranged, the black sealing material can also contribute to preventing color mixture of RGB and improving contrast.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2019-204905
Patent document 2: japanese patent laid-open publication No. 2017-203810
Patent document 3: japanese Kohyo publication 2018-523854
Disclosure of Invention
Problems to be solved by the invention
When the black sealing material is used, the light emitting element such as an LED chip is covered with the black sealing material having a reduced transmittance for visible light at the upper portion (image display side), which causes a problem of a reduction in light emission efficiency and a problem of a darkening of an image. In order to cope with this problem, there is also a problem of an increase in power consumption when the output power of the LED chip is increased to increase the emission luminance.
In the case where the transmittance of the black encapsulant with respect to visible light is increased in order to improve the light emission efficiency, there is a trade-off relationship among the antireflection function of the metal wiring and the like, prevention of color mixing of RGB, and a decrease in contrast, and it is difficult to achieve both of them.
On the other hand, as the black sealing material, a liquid curable resin containing a black colorant (dye or pigment) or an adhesive is used. When a liquid curable resin containing a black colorant is used, there is a problem that unevenness occurs in blackness due to unevenness in thickness. In addition, pigments are often selected because they are superior to dyes in both heat resistance and weather resistance, but when a liquid curable resin in which pigments are dispersed is used, problems such as uneven filling of the liquid curable resin during filling and uneven dispersion of the pigments during flowing occur in addition to the above-described thickness unevenness. Further, there is a problem that the surface of the liquid curable resin cured after sealing has no adhesive force, and the covering member needs to be laminated using an adhesive or the like, which requires more man-hours and members.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical laminate suitable for manufacturing a self-luminous display device such as a Mini/Micro LED display device in which the light emission efficiency is improved and the antireflection function and the contrast of metal wiring and the like are improved.
Another object of the present invention is to reduce the number of steps and necessary members in the manufacturing process of the self-luminous display device.
Means for solving the problems
As a result of intensive studies to achieve the above object, the present inventors have found that a self-luminous display device having both an improved light emission efficiency and an improved antireflection function and contrast of metal wiring and the like can be manufactured by using an optical laminate obtained by laminating 2 adhesive layers having different transmittances and further laminating a base material for manufacturing the self-luminous display device. It has also been found that the use of the optical laminate enables reduction in the number of steps and necessary members, and enables efficient production of a self-luminous display device having improved luminous efficiency, antireflection function of metal wiring and the like, and contrast. The present invention has been completed based on these findings.
That is, a first aspect of the present invention provides an optical laminate having a laminate structure in which a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer, and a substrate are laminated in this order, the first pressure-sensitive adhesive layer having a visible light transmittance T 1 And a visible light transmittance T of the second adhesive layer 2 Satisfy T 1 <T 2 。
In the optical laminate according to the first aspect of the present invention, the first pressure-sensitive adhesive layer has a visible light transmittance T 1 And a visible light transmittance T of the second adhesive layer 2 Satisfy T 1 <T 2 That is, the visible light transmittance of the first pressure-sensitive adhesive layer is preferably lower than the visible light transmittance of the second pressure-sensitive adhesive layer in terms of: by using the optical laminate of the first aspect of the present invention for the production of a self-luminous display device, the first adhesive layer prevents reflection due to metal wiring or the like on the display panel, prevents color mixing between the arranged light-emitting elements, and improves contrast. Furthermore, this solution is suitable in the following respects: the second pressure-sensitive adhesive layer, which exhibits a higher visible light transmittance than the first pressure-sensitive adhesive layer, is formed on the upper portion (image display side) of the light-emitting element, so that the light-emitting efficiency can be improved, the image can be brightened, and the power consumption due to the increase in output power for improving the light-emitting luminance can be reduced.
That is, the optical layered body according to the first aspect of the present invention has such a configuration, and thus, while improving the light emission efficiency, it solves the problems of the antireflection function of the metal wiring and the like, the prevention of color mixing of RGB, and the improvement of contrast, which are in trade-off relation with the light emission efficiency.
In addition, when the optical laminate according to the first aspect of the present invention is used for manufacturing a self-luminous display device, the laminated structure of the first adhesive layer and the second adhesive layer constitutes a sealing material for sealing the light-emitting elements arranged on the display panel, and the base material constitutes the outermost layer of the covering member, so that it is not necessary to laminate a covering member after sealing, the number of steps and necessary members can be reduced, and the manufacturing efficiency can be improved.
Further, the case where the sealing material for sealing the light emitting element is a pressure-sensitive adhesive layer having a laminated structure of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is preferable for the following reason: when the light-emitting element is packaged with the adhesive layer in the production of a self-luminous display device, the above-described unevenness in blackness due to the unevenness in thickness, the unevenness in filling, the unevenness in dispersion of the pigment, and the like is less likely to occur, and further, the antireflection of metal wiring and the like, the prevention of color mixing of RGB, and the contrast can be improved.
In the optical laminate according to the first aspect of the present invention, the first pressure-sensitive adhesive layer preferably has a visible light transmittance T 1 And the visible light transmittance T of the base material 3 Satisfy T 1 <T 3 . This is preferable in that the light emission efficiency can be improved.
In the optical laminate according to the first aspect of the present invention, the first pressure-sensitive adhesive layer preferably has a visible light transmittance T 1 Is 80% or less. This embodiment is preferable in further improving the antireflection function of the metal wiring and the like, color mixture prevention of RGB, and contrast. Further, it is preferable that the visible light transmittance T of the second adhesive layer is 2 85 to 100 percent. This embodiment is suitable for further improving the above-described light emission efficiency. Namely, the visible light transmittance T of the first pressure-sensitive adhesive layer 1 80% or less of the visible light transmittance T of the second adhesive layer 2 85 to 100% is highly suitable in the following respects: the light emitting efficiency is improved, and the anti-reflection function of metal wiring and the like, the prevention of color mixing of RGB, and the improvement of contrast are balanced.
In the optical laminate according to the first aspect of the present invention, the first adhesive layer and the second adhesive layer are preferably adhesive layers formed from an adhesive composition selected from the group consisting of a photocurable adhesive composition and a solvent-based adhesive composition. Preferably, the binder composition forming the first binder layer contains a colorant. These protocols are suitable in the following respects: form the aforementioned T 1 And the aforementioned T 2 Satisfy T 1 <T 2 The above-mentioned light emission efficiency, antireflection function of metal wiring and the like, prevention of color mixture of RGB, and contrast are further improved.
In the optical laminate according to the first aspect of the present invention, the pressure-sensitive adhesive composition preferably contains an acrylic polymer. Preferably, the acrylic polymer contains a (meth) acrylic block copolymer. Preferably, the adhesive composition forming the first adhesive layer is a solvent-based adhesive composition containing a (meth) acrylic block copolymer. These solutions are preferred in the following respects: when the optical laminate of the first aspect of the present invention is used for manufacturing a self-luminous display device, the first adhesive layer and the second adhesive layer (particularly, the first adhesive layer) fill the level difference of the light-emitting elements arranged on the display panel without a gap, and the optical laminate is excellent in level difference absorption and also excellent in processability.
In the optical laminate according to the first aspect of the present invention, the thickness of the first pressure-sensitive adhesive layer is preferably 10 to 300 μm, and more preferably 15 to 200 μm. The thickness of the second pressure-sensitive adhesive layer is preferably 1 to 500. Mu.m, more preferably 10 to 300. Mu.m, and still more preferably 15 to 200. Mu.m. The ratio of the thickness of the second pressure-sensitive adhesive layer to the thickness of the first pressure-sensitive adhesive layer (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is preferably 1.0 to 5.0, more preferably 1.2 to 4.0, and still more preferably 1.3 to 3.0. These solutions are preferred in the following respects: by sufficiently sealing the space between the light emitting elements arranged on the display panel of the self-luminous display device with the first adhesive layer, reflection of metal wiring or the like is prevented, color mixing of RGB is prevented, and contrast is improved, and by covering the upper portion (image display side) of the light emitting element with the second adhesive layer having high permeability, light emission efficiency can be improved.
In the optical laminate according to the first aspect of the present invention, the surface of the base material on which the second pressure-sensitive adhesive layer is not laminated is preferably subjected to an antireflection treatment and/or an antiglare treatment. Preferably, the antireflection treatment and/or the antiglare treatment is an antiglare layer provided on one surface of the substrate. Preferably, the antiglare layer is formed using an antiglare layer-forming material containing a resin, particles, and a thixotropic agent, and the antiglare layer has an aggregate portion on the surface of the antiglare layer, the aggregate portion forming a convex portion, by aggregation of the particles and the thixotropic agent. Preferably, the convex portion on the surface of the antiglare layer has an average inclination angle θ a (°) in the range of 0.1 to 5.0. These solutions are preferred in the following respects: the surface of the optical laminate of the first aspect of the present invention is provided with an antireflection function and/or an antiglare function, and the surface is prevented from being degraded in visibility due to reflection of external light, reflection of an image, and the like, and is adjusted in aesthetic properties such as glossiness.
The optical laminate according to the first aspect of the present invention may further include a surface protective film laminated on the surface of the substrate on which the second pressure-sensitive adhesive layer is not laminated. This solution is suitable in the following respects: the optical laminate and the optical product including the same are prevented from being damaged or contaminated during production, transportation, and shipment of the optical laminate.
Further, a second aspect of the present invention provides a self-luminous display device including: the present invention is directed to a display panel in which a plurality of light-emitting elements are arranged on one surface of a substrate, and an optical laminate according to the first aspect of the present invention, wherein the surface of the display panel on which the light-emitting elements are arranged is laminated with a first adhesive layer of the optical laminate. 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 surface of a substrate. This scheme is preferable in the following respects: the self-luminous display device of the second aspect of the present invention can improve the light emission efficiency and prevent the reflection of metal wiring on the substrate, prevent color mixing of RGB, and improve the contrast.
ADVANTAGEOUS EFFECTS OF INVENTION
When the optical laminate of the present invention is used for manufacturing a self-luminous display device, a self-luminous display device having improved luminous efficiency, antireflection function of metal wiring, and the like, and contrast can be manufactured efficiently.
Drawings
Fig. 1 is a schematic view (cross-sectional view) showing one embodiment of an optical laminate of the present invention.
Fig. 2 is a schematic diagram (cross-sectional view) showing another embodiment of the optical stack of the present invention.
Fig. 3 is a schematic view (cross-sectional view) showing another embodiment of the optical stack of the present invention.
Fig. 4 is a schematic view (cross-sectional view) showing one embodiment of a self-luminous display device (Mini/Micro LED display device) of the present invention.
Fig. 5 is a schematic view (cross-sectional view) showing another embodiment of a self-luminous display device (Mini/Micro LED display device) of the present invention.
Fig. 6 is a schematic view (cross-sectional view) showing another embodiment of a self-luminous display device (Mini/Micro LED display device) of the present invention.
Detailed Description
A first aspect of the invention provides an optical stack. The optical laminate according to the first aspect of the present invention has a laminate structure in which a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer, and a substrate are laminated in this order. The visible light transmittance T of the first adhesive layer 1 And a visible light transmittance T of the second adhesive layer 2 Is to satisfy T 1 <T 2 In (3).
The term "optical" in the optical laminate of the first aspect of the present invention means to be used for optical applications, more specifically, means to be used for production of products using optical members (optical products) and the like. The optical product includes, for example, an input device such as an image display device and a touch panel, and is preferably a self-luminous display device such as a Mini/Micro LED display device and an organic EL (electroluminescence) display device, and can be suitably used for manufacturing the Mini/Micro LED display device in particular.
Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto and is only exemplary.
Fig. 1 to 3 are schematic diagrams (cross-sectional views) showing one embodiment of an optical stack according to a first aspect of the present invention. Fig. 4 to 6 are schematic diagrams (cross-sectional views) showing an embodiment of a self-light emitting display device (Mini/Micro LED display device) according to a second aspect of the present invention.
In fig. 1, the optical laminate 10 has a laminate structure in which a first pressure-sensitive adhesive layer 1, a second pressure-sensitive adhesive layer 2, and a substrate 3 are laminated in this order. In fig. 2, the optical laminate 11 is subjected to an antireflection treatment and/or an antiglare treatment 4 on the surface 3a of the substrate 3 on which the second pressure-sensitive adhesive layer 2 is not laminated. In fig. 3, the optical laminate 12 has an antiglare layer 4a formed as an antireflection treatment and/or an antiglare treatment on a surface 3a of the base material 3 on which the second pressure-sensitive adhesive layer 2 is not laminated.
In the present embodiment, the first pressure-sensitive adhesive layer 1 has a visible light transmittance T 1 And the visible light transmittance T of the second adhesive layer 2 2 Satisfy T 1 <T 2 . That is, the visible light transmittance of the first adhesive layer 1 is lower than that of the second adhesive layer 2.
In fig. 4, a self-luminous display device (Mini/Micro LED display device) 20 includes a display panel in which a plurality of LED chips 7 are arranged on one surface of a substrate 5, and an optical laminate 10 according to the first aspect of the present invention. The surface of the display panel on which the LED chips 7 are arranged is laminated with the first adhesive layer 1 of the optical laminate 10. In fig. 5, a self-light-emitting display device (Mini/Micro LED display device) 21 is subjected to an antireflection treatment and/or an antiglare treatment 4 on a surface 3a of a base material 3 on which a second pressure-sensitive adhesive layer 2 is not laminated. In fig. 6, a self-light-emitting display device (Mini/Micro LED display device) 22 has an antiglare layer 4a formed as an antireflection treatment and/or an antiglare treatment on a surface 3a of a base material 3 on which a second adhesive layer 2 is not laminated.
In the present embodiment, a metal wiring layer 6 for transmitting a light emission control signal to each LED chip 7 is laminated on a substrate 5 of the display panel. The LED chips 7 emitting light of red (R), green (G), and blue (B) colors are alternately arranged on the substrate 5 of the display panel via the metal wiring layer 6. The metal wiring layer 6 is formed of a metal such as copper, and reflects light emitted from each LED chip 7, thereby reducing visibility of an image. Further, the light emitted from each LED chip 7 of each of RGB colors is mixed, and the contrast is lowered.
In the present embodiment, each LED chip 7 arranged on the display panel is encapsulated by the first adhesive layer 1 and the second adhesive layer 2 without a gap. That is, the laminated structure of the first adhesive layer 1 and the second adhesive layer 2 may constitute the encapsulating material of each LED chip 7.
In the present embodiment, the first adhesive layer 1 encapsulates the metal wiring layer 6 and the LED chips 7 arranged on the display panel. By making the visible light transmittance of the first adhesive layer 1 lower than that of the second adhesive layer 2, sufficient light shielding properties in the visible light region are provided. Since the first pressure-sensitive adhesive layer 1 having higher light-shielding properties encapsulates the LED chips 7 without any gap therebetween, color mixing between the LED chips 7 can be prevented, and contrast can be improved. Further, since the first adhesive layer 1 having higher light-shielding properties also encapsulates the surface of the metal wiring layer 6, reflection by the metal wiring layer 6 can be prevented.
In the present embodiment, the second adhesive layer 2 encapsulates the upper portions (display image side) of the LED chips 7 arranged on the display panel. By making the visible light transmittance of the second adhesive layer 2 higher than that of the first adhesive layer 1, sufficient transmittance in the visible light region is obtained. Since the second adhesive layer 2 having higher permeability encapsulates the upper portion (on the display image side) of each LED chip 7, absorption of visible light emitted from each LED chip 7 can be suppressed to be low, and the light emission efficiency can be improved, whereby an image can be made brighter. In addition, since it is not necessary to increase the output power to increase the light emission luminance, the power consumption can be suppressed to be low.
The Mini/Micro LED display device of the present embodiment can be manufactured by bonding a display panel having a plurality of LED chips arranged on one surface of a substrate to the first adhesive layer of the optical laminate of the present embodiment. In this case, the base material 3 may constitute a covering member forming the outermost layer of the self-luminous display device (Mini/Micro LED display device). Therefore, according to the present embodiment, the step of separately attaching the covering member can be omitted, the number of necessary members and steps can be reduced, and the production efficiency can be improved.
In the Mini/Micro LED display device 21 of the present embodiment, the surface 3a of the base material 3 is subjected to the antireflection treatment and/or the antiglare treatment 4, and in the Mini/Micro LED display device 22, the antiglare layer 4a is formed as the antireflection treatment on the surface 3a of the base material 3. The antireflection treatment and/or the antiglare treatment 4, particularly the antiglare layer 4a prevents a decrease in visibility at the surface 3a of the base material 3 as a covering member caused by reflection of external light, reflection of an image, or the like, and/or adjusts the beauty such as glossiness.
Hereinafter, each configuration will be described in detail.
< substrate >
In the present embodiment, the substrate 3 is not particularly limited, and examples thereof include glass, transparent plastic film substrates, and the like. The transparent plastic film substrate is not particularly limited, but a substrate having excellent visible light transmittance and excellent transparency (preferably a substrate having a haze value of 5% or less) is preferable, and examples thereof include a transparent plastic film substrate described in japanese patent application laid-open No. 2008-90263. As the transparent plastic film substrate, a substrate having little optical birefringence can be suitably used. In the present embodiment, the substrate 3 may be used as a cover member of a self-luminous display device, for example, and in this case, a film made of triacetyl cellulose (TAC), polycarbonate, an acrylic polymer, polyolefin having a cyclic or norbornene structure, or the like is preferable as the transparent plastic film substrate. In addition, the base material 3 may be the aforementioned covering member itself in the present embodiment. With this configuration, the number of steps for separately laminating the cover member can be reduced in the manufacturing of the self-luminous display device, and therefore, the number of steps and necessary members can be reduced, and the production efficiency can be improved. In addition, if this is the case, the covering member can be further thinned. When the substrate 3 is a cover member, the surface 3a constitutes the outermost surface of the self-luminous display device.
In the optical laminate of the present embodiment, the visible light transmittance T of the first pressure-sensitive adhesive layer 1 is preferably set to be lower than that of the second pressure-sensitive adhesive layer 1 1 And the visible light transmittance T of the base material 3 3 Satisfy T 1 <T 3 . This solution is suitable in the following respects: by forming the substrate 3, which exhibits a higher visible light transmittance than the first pressure-sensitive adhesive layer 1, on the upper portion (image display side) of the light-emitting element, it is possible to improve the light emission efficiency, brighten the image, and reduce power consumption due to an increase in output power for improving the light emission luminance. Visible light transmittance T to the base material 3 3 The content is not particularly limited, and may be, for example, 85 to 100%, or 88% or moreMore than 90% or more than 92%.
In the present embodiment, the thickness of the base material 3 is not particularly limited, but is preferably in the range of 10 to 500. Mu.m, more preferably in the range of 20 to 300. Mu.m, and most preferably in the range of 30 to 200. Mu.m, in view of, for example, strength, workability such as workability, and thin-layer property. The refractive index of the substrate 3 is not particularly limited, and is, for example, in the range of 1.30 to 1.80, preferably in the range of 1.40 to 1.70.
In the present embodiment, it is preferable that the surface 3a of the base material 3 is subjected to a reflective surface treatment and/or an antiglare treatment 4. When the surface 3a of the base material 3 is subjected to the reflection surface treatment and/or the anti-glare treatment 4, the surface 3a constitutes the outermost surface of the self-luminous display device, and it is possible to prevent deterioration of visibility due to reflection of external light, reflection of an image, or the like, and to adjust the appearance such as glossiness. An anti-glare treatment that is easy and low cost to manufacture is preferred.
The anti-reflection treatment may be any known anti-reflection treatment without particular limitation, and for example, anti-reflection (AR) treatment may be mentioned.
The anti-reflection (AR) treatment may be performed by applying a known AR treatment without any particular limitation, and specifically, may be performed by forming two or more optical films having strictly controlled thickness and refractive index or an anti-reflection layer (AR layer) obtained by laminating the optical films on one surface 3a of the substrate 3. The AR layer exhibits an antireflection function by canceling out reverse phases of incident light and reflected light by an interference effect of light. The wavelength region of visible light rays exhibiting an antireflection function is, for example, 380 to 780nm, and particularly the wavelength region with high visual sensitivity is in the range of 450 to 650nm, and it is preferable to design the AR layer so that the reflectance at 550nm of the center wavelength is minimized.
The AR layer is generally a multilayer antireflection layer having a structure in which two or five optical thin layers (thin films having strictly controlled thicknesses and refractive indices) are laminated, and by forming a plurality of layers of components having different refractive indices only in a predetermined thickness, the degree of freedom in optical design of the AR layer is improved, the antireflection effect can be further improved, and the spectral reflectance characteristics can be made uniform (flat) in the visible light region. Since the optical thin film is required to have high thickness accuracy, the formation of each layer is generally performed by vacuum deposition, sputtering, CVD, or the like which is a dry method.
The anti-glare (AG) treatment may be any known AG treatment, and may be performed by forming an anti-glare layer 4a on the surface 3a of the base material 3. As the antiglare layer 4a, a known antiglare layer can be used without limitation, and is generally formed as a layer in which inorganic or organic particles as an antiglare agent are dispersed in a resin.
In the present embodiment, the antiglare layer 4a is formed using an antiglare layer-forming material containing a resin, particles, and a thixotropy-imparting agent, and the particles and the thixotropy-imparting agent aggregate to form a convex portion on the surface of the antiglare layer 4a. According to this embodiment, the antiglare layer 4a has excellent display characteristics in which both antiglare properties and white blur prevention are achieved, and even though the antiglare layer is formed by aggregation of particles, generation of a projecting object on the surface of the antiglare layer, which is an appearance defect, can be prevented, and the yield of products can be improved.
Examples of the resin include: the thermosetting resin is an ionizing radiation curable resin which is cured by ultraviolet rays or light. As the resin, a commercially available thermosetting resin, ultraviolet curable resin, or the like can be used.
Examples of the thermosetting resin and the ultraviolet curable resin include curable compounds having at least one of an acrylate group and a methacrylate group, which are cured by heat, light (ultraviolet rays, etc.), an electron beam, or the like, and examples thereof include: and oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiolpolyene resins, and polyols. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.
The resin may be a reactive diluent having at least one of an acrylate group and a methacrylate group. The reactive diluent may be, for example, one described in jp 2008-88309 a, and examples thereof include monofunctional acrylates, monofunctional methacrylates, multifunctional acrylates, and multifunctional methacrylates. The reactive diluent is preferably an acrylate having 3 or more functions or a methacrylate having 3 or more functions. This is because the hardness of the antiglare layer 4a can be made excellent. Examples of the reactive diluent include: butanediol glyceryl ether diacrylate, an acrylate ester of isocyanuric acid, a methacrylate ester of isocyanuric acid, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.
The particles for forming the antiglare layer 4a impart antiglare properties by making the surface of the formed antiglare layer 4a uneven, and control the haze value of the antiglare layer 4a are main functions. The haze value of the antiglare layer 4a can be designed by controlling the difference in refractive index between the aforementioned particles and the aforementioned resin. Examples of the particles include inorganic particles and organic particles. The inorganic particles are not particularly limited, and examples thereof include: silica particles, titanium oxide particles, alumina particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, calcium sulfate particles, and the like. The organic particles are not particularly limited, and examples thereof include: 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 resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyvinyl fluoride resin powder, and the like. These inorganic particles and organic particles may be used alone or in combination of two or more.
The weight average particle diameter (D) of the particles is preferably in the range of 2.5 to 10 μm. By making the weight average particle diameter of the foregoing particles the foregoing range, for example, the antiglare property is more excellent, and white blurring can be prevented. The weight average particle diameter of the particles is more preferably in the range of 3 to 7 μm. The weight average particle diameter of the particles can be measured by, for example, the coulter counter method. For example, the number and volume of the particles are measured by measuring the resistance of the electrolyte solution corresponding to the volume of the particles when the particles pass through the pores using a particle size distribution measuring apparatus (trade name: coulter particle size Analyzer, manufactured by Beckman Coulter, inc.) using a pore resistance method, and the weight average particle diameter is calculated.
The shape of the particles is not particularly limited, and may be, for example, roughly spherical in the form of beads, or may be amorphous particles such as powder, and roughly spherical particles are preferable, roughly spherical particles having an aspect ratio of 1.5 or less are more preferable, and spherical particles are most preferable.
The proportion of the particles in the antiglare layer 4a 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, and still more preferably in the range of 1 to 7 parts by weight, relative to 100 parts by weight of the resin. By setting the above range, for example, the antiglare property is more excellent and white blur can be prevented.
Examples of the thixotropic agent for forming the antiglare layer 4a include: organoclays, oxidized polyolefins, modified ureas, and the like.
The organoclay is preferably organically treated clay in order to improve the affinity with the resin. Examples of the organoclay include a layered organoclay. The organoclay may be prepared by itself 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 name, all Co-op Chemical Co., manufactured by Ltd.); S-BEN, S-BEN C, S-BEN E, S-BEN W, S-BEN P, S-BEN WX, S-BEN-400, S-BEN NX80, S-BEN NO12S, S-BEN NEZ, S-BEN NO12, S-BEN NE, S-BEN NZ70, ORGANITE D, ORGANITE T (trade names, manufactured by HOJUN Co., ltd.); kuipif, kuipia G4 (trade name, both manufactured by kuimine INDUSTRIES co., ltd.); TIXOGEL VZ, CLAYTONE HT, CLAYTONE40 (trade name, all manufactured by Rockwood Additives Ltd.) and the like.
The oxidized polyolefin may be prepared by itself or a commercially available product may be used. Examples of the commercially available products include: DISPARLON 4200-20 (trade name, manufactured by NAKAI CHENJIAO Co., ltd.), FLOWNON SA300 (trade name, manufactured by Kyoho chemical Co., ltd.), and the like.
The modified urea is a reactant of isocyanate monomer or adduct thereof and organic amine. The modified urea may be prepared by itself or may be a commercially available product. Examples of the commercially available products include: BYK410 (BYK chemical), and the like.
The thixotropic agent may be used singly or in combination of two or more.
In the present embodiment, it is preferable that the height of the convex portion from the roughness average line of the antiglare layer 4a is less than 0.4 times the thickness of the antiglare layer 4a. 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. If the amount is within this range, it is possible to suitably prevent the formation of projections which may cause defects in the appearance of the projecting portion. The convex portion having such a height makes it possible to prevent appearance defects from occurring in the antiglare layer 4a of the present embodiment. Here, the height of the distance average line can be measured by, for example, the method described in japanese patent application laid-open No. 2017-138620.
The proportion of the thixotropic agent in the antiglare layer 4a is preferably in the range of 0.1 to 5 parts by weight, and 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 antiglare layer 4a is not particularly limited, and is preferably within a range of 3 to 12 μm. By setting the thickness (d) of the antiglare layer 4a to the above range, for example, occurrence of curling of the optical laminate 12 can be prevented, and a problem of a decrease in productivity such as a conveyance failure can be avoided. When the thickness (D) is in the above range, the weight-average particle diameter (D) of the particles is preferably in the range of 2.5 to 10 μm, as described above. By making the thickness (D) of the antiglare layer 4a and the weight average particle diameter (D) of the particles the aforementioned combination, the antiglare property can be made more excellent. The thickness (d) of the antiglare layer 4a is more preferably in the range of 3 to 8 μm.
Regarding the relationship between the thickness (D) of the antiglare layer 4a and the weight-average particle diameter (D) of the particles, it is preferable that D/D is in the range of 0.3. Ltoreq. D.ltoreq.0.9. By doing so, the antiglare property is further improved, white blurring can be prevented, and an antiglare layer free from appearance defects can be formed.
In the optical laminate 12 of the present embodiment, as described above, the antiglare layer 4a is formed with the convex portion on the surface of the antiglare layer 4a by the aggregation of the particles and the thixotropy imparting agent. At the aggregated portion where the convex portion is formed, the particles are present in a state of being aggregated in a plurality in the plane direction of the antiglare layer 4a. Thereby, the convex portion is formed into a smooth shape. The antiglare layer 4a of the present embodiment can prevent white blur while maintaining antiglare properties by having the convex portion with such a shape, and further can make appearance defects less likely to occur.
The surface shape of the antiglare layer 4a can be arbitrarily designed by controlling the aggregation state of particles contained in the antiglare layer-forming material. The aggregation 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, affinity for a solvent or a resin, or the like), the type or combination of the resin (binder) and the solvent. Here, the present embodiment can control the aggregation state of the particles by the thixotropic agent contained in the anti-glare layer forming material. As a result, in the present embodiment, the aggregation state of the particles can be made as described above, and the convex portion can be formed into a smooth shape.
In the optical laminate 12 of the present embodiment, when the base material 3 is formed of a resin or the like, it is preferable to have a penetration layer at the interface between the base material 3 and the antiglare layer 4a. The penetration layer is formed by penetrating the resin component contained in the material for forming the antiglare layer 4a into the base material 3. It is preferable that the penetration layer is formed to improve the adhesion between the base material 3 and the antiglare layer 4a. The thickness of the permeation 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 substrate 3 is triacetyl cellulose and the resin included in the antiglare layer 4a is an acrylic resin, the permeation layer can be formed. The permeation layer can be confirmed by, for example, observing the cross section of the optical layered body 12 with a Transmission Electron Microscope (TEM), and the thickness can be measured.
Even when the present embodiment is applied to the optical laminate 12 having such a penetration layer, it is possible to easily form a desired smooth surface irregularity shape that achieves both the antiglare property and the prevention of white blur. In the permeation layer, the base material 3 is preferably formed thick to improve adhesiveness, as the adhesion to the antiglare layer 4a is poor.
In the present embodiment, it is preferable that the average of appearance defects having a maximum diameter of 200 μm or more in the antiglare layer 4a is 1m or more 2 The number of the antiglare layer 4a is 1 or less. More preferably, the aforementioned appearance defect is not present.
In the present embodiment, the substrate 3 on which the antiglare layer 4a is formed preferably has a haze value in the range of 0 to 10%. The haze value refers to a haze value (haze) according to JIS K7136 (2000 edition). The haze value is more preferably in the range of 0 to 5%, and still more preferably in the range of 0 to 3%. In order to set the haze value in the above range, the particles and the resin are preferably selected so that the difference in refractive index between the particles and the resin is in the range of 0.001 to 0.02. By setting the haze value to the above range, a sharp image can be obtained, and the contrast in a dark place can be improved.
In the present embodiment, the average inclination angle θ a (°) at the irregularities on the surface of the antiglare layer 4a is preferably in the range of 0.1 to 5.0, more preferably in the range of 0.3 to 4.5, even 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 θ a is a value defined by the following equation (1). The average tilt angle θ a is a value measured by a method described in japanese patent application laid-open No. 2017-138620, for example.
Mean inclination angle θ a = tan-1 Δ a (1)
In the above formula (1), Δ a is a value obtained by dividing the reference length L by the sum (h 1+ h2+ h3 \8230; + hn) of the differences (height h) between the peaks and the valleys of the adjacent mountains in the reference length L of the roughness curve defined in JIS B0601 (1994 version), as shown in the following formula (2). The roughness curve is a curve obtained by removing a surface waviness component longer than a predetermined wavelength from a cross-sectional curve by a phase difference compensation type high-pass filter. The cross-sectional curve is a contour appearing at a cut when the target surface is cut on a plane perpendicular to the target surface.
Δa＝(h1+h2+h3…+hn)/L (2)
If θ a is in the above range, the antiglare property is more excellent and white blur can be prevented.
In forming the antiglare layer 4a, the prepared antiglare layer-forming material (coating liquid) preferably exhibits thixotropy, and the Ti value specified below is preferably in the range of 1.3 to 3.5, more preferably in the range of 1.3 to 2.8.
Ti value = β 1/β 2
Here, β 1 is a viscosity measured at a shear rate of 20 (1/s) using RheoStress 6000 manufactured by HAAKE, and β 2 is a viscosity measured at a shear rate of 200 (1/s) using RheoStress 6000 manufactured by HAAKE.
If the Ti value is less than 1.3, appearance defects are liable to occur, and the anti-glare property, the property regarding white blur, is deteriorated. Further, if the Ti value exceeds 3.5, the particles are less likely to aggregate, and a dispersed state is easily formed.
The method for producing the antiglare layer 4a of the present embodiment is not particularly limited, and the antiglare layer can be produced by any method, for example, by preparing an antiglare layer-forming material (coating liquid) containing the resin, the particles, the thixotropy-imparting agent, and a solvent, applying the antiglare layer-forming material (coating liquid) to the surface 3a of the base material 3 to form a coating film, and curing the coating film to form the antiglare layer 4a. In the present embodiment, a method of providing a concave-convex shape by an appropriate method such as a transfer method using a mold, sandblasting, or emboss roller may be used in combination.
The solvent is not particularly limited, and various solvents can be used, and one solvent may be used alone, or two or more solvents may be used in combination. The kind and the ratio of the solvent are optimum depending on the composition of the resin, the kinds and the contents of the particles and the thixotropic agent. The solvent is not particularly limited, and examples thereof include: alcohols such as methanol, ethanol, isopropanol, butanol, and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone; esters such as methyl acetate, ethyl acetate, and 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, and xylene.
As the substrate 3, for example, in the case of forming a permeation layer using triacetyl cellulose (TAC), a good solvent for TAC may be suitably used. Examples of the solvent include: ethyl acetate, methyl ethyl ketone, cyclopentanone, and the like.
Further, by appropriately selecting the solvent, the thixotropy of the antiglare layer-forming material (coating liquid) by the thixotropy-imparting agent can be exhibited well. For example, in the case of using an organoclay, toluene and xylene may be suitably used alone or in combination, for example, in the case of using an oxidized polyolefin, methyl ethyl ketone, ethyl acetate, propylene glycol monomethyl ether may be suitably used alone or in combination, and for example, in the case of using a modified urea, butyl acetate and methyl isobutyl ketone may be suitably used alone or in combination.
Various leveling agents may be added to the above-described antiglare layer-forming material. For the purpose of preventing coating unevenness (uniformity of the coated surface), for example, a fluorine-based or silicone-based leveling agent can be used as the leveling agent. In the present embodiment, the leveling agent can be appropriately selected depending on the case where the surface of the antiglare layer 4a is required to have antifouling property, the case where an antireflection layer (low refractive index layer) or a layer containing an interlayer filler is to be formed on the antiglare layer 4a, or the like. The present embodiment can make the coating liquid exhibit thixotropy by including the aforementioned thixotropy-imparting agent, for example, and thus is less likely to cause coating unevenness. Thus, this embodiment has, for example, the advantage that the option of the aforementioned leveling agent can be extended.
The amount of the leveling agent is, for example, 5 parts by weight or less, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the resin.
The material for forming an antiglare layer may contain, as necessary, a pigment, a filler, a dispersant, a plasticizer, an ultraviolet absorber, a surfactant, an antifouling agent, an antioxidant, and the like, as long as the performance is not impaired. These additives may be used singly or in combination of two or more.
As the material for forming the antiglare layer, a conventionally known photopolymerization initiator such as that described in japanese patent application laid-open No. 2008-88309 can be used.
As a method of applying the antiglare layer-forming material to the surface 3a of the base material 3, for example, an application method such as a jet coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, or a bar coating method can be used.
The antiglare layer forming material is applied to form a coating film on the substrate 3, and the coating film is cured. The coating film is preferably dried before the curing. The drying may be, for example, natural drying, air drying by blowing, heat drying, or a combination thereof.
The curing means of the coating film of the antiglare layer-forming material is not particularly limited, and ultraviolet curing is preferred. The irradiation amount of the energy ray source is preferably 50 to 500mJ/cm in terms of the cumulative exposure amount at an ultraviolet wavelength of 365nm 2 . If the irradiation dose is 50mJ/cm 2 As described above, the curing is more sufficient, and the hardness of the antiglare layer formed is also more sufficient. Further, if it is 500mJ/cm 2 The coloring of the formed antiglare layer can be prevented as follows.
As described above, the antiglare layer 4a may be formed on the surface 3a of the substrate 3. Note that the antiglare layer 4a may be formed by a manufacturing method other than the aforementioned method. The hardness of the antiglare layer 4a of the present embodiment is preferably 2H or more in pencil hardness, although it is influenced by the thickness of the layer.
In the present embodiment, the antiglare layer 4a may have a multilayer structure in which two or more layers are stacked.
In the present embodiment, the AR layer (low refractive index layer) may be disposed on the antiglare layer 4a. For example, when the optical layered body 12 of the present embodiment is mounted on a self-luminous display device, reflection of light at the interface between air and an antiglare layer is one of the main factors that reduce visibility of an image. The AR layer reduces the surface reflection. The antiglare layer 4a and the antireflection layer may each have a multilayer structure in which two or more layers are stacked.
Further, in order to prevent the adhesion of contaminants and to improve the ease of removal of the contaminants adhered, it is preferable to stack an anti-contamination layer formed of a fluorine-containing silane-based compound, a fluorine-containing organic compound, or the like on the antiglare layer 4a.
In the present embodiment, at least one of the substrate 3 and the antiglare layer 4a is preferably subjected to surface treatment. When the surface of the base material 3 is surface-treated, the adhesion to the antiglare layer 4a is further improved. Further, if the surface of the antiglare layer 4a is surface-treated, the adhesion to the AR layer is further improved.
In order to prevent the substrate 3 from curling, the other side of the antiglare layer 4a may be solvent-treated. Further, in order to prevent the occurrence of curling, a transparent resin layer may be formed on the other surface of the antiglare layer 4a.
< adhesive layer >
In the present embodiment, the first adhesive layer 1 and the second adhesive layer 2 are adhesive layers formed from an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition.
In the present embodiment, the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 may be both pressure-sensitive adhesive layers formed from a photocurable pressure-sensitive adhesive composition, may be both pressure-sensitive adhesive layers formed from a solvent-based pressure-sensitive adhesive composition, may be one pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition, and may be the other pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition.
In the present embodiment, the first pressure-sensitive adhesive layer 1 is preferably a pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition in terms of excellent level difference absorption and also excellent processability. On the other hand, the second adhesive layer 2 may be an adhesive layer formed from a photocurable adhesive composition or may be an adhesive layer formed from a solvent-based adhesive composition.
The adhesive composition forming the first adhesive layer 1 preferably contains a colorant. When the binder composition for forming the first binder layer 1 contains a colorant, the first binder layer 1 has a reduced transmittance for visible light, and the above-mentioned T is formed 1 And the aforementioned T 2 Satisfy T 1 <T 2 Is preferable. By sealing the space between the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini/Micro LED display device) of the present embodiment with the first pressure-sensitive adhesive layer 1 having reduced transparency to visible light and imparted light-shielding properties, reflection due to the metal wiring or the like can be prevented, color mixing between the LED chips can be prevented, and the contrast of an image can be improved.
The adhesive composition for forming the second adhesive layer 2 may contain a colorant, but is selected from the group consisting of 1 And the aforementioned T 2 Satisfy T 1 <T 2 From the viewpoint of the embodiment of (1), it is preferable that no colorant is contained.
< Photocurable adhesive composition >
The photocurable adhesive composition includes a polymer, a photopolymerizable compound, and a photopolymerization initiator. That is, the photocurable adhesive composition used for forming the first adhesive layer 1 and the second adhesive layer 2 of the present embodiment contains a polymer, a photopolymerizable compound, and a photopolymerization initiator.
The adhesive layer formed using the photocurable adhesive composition is roughly divided into: an adhesive layer of the type that undergoes photocuring (first mode); and an adhesive layer of a type which is not photocured and is photocured after being bonded to a display panel described later (second embodiment). The first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 may be both pressure-sensitive adhesive layers of the first embodiment, may be both pressure-sensitive adhesive layers of the second embodiment, or may be both pressure-sensitive adhesive layers of the first embodiment, and may be both pressure-sensitive adhesive layers of the second embodiment.
[ first mode ]
The adhesive layer of the first embodiment can be formed by applying a photocurable adhesive composition containing a polymer, a photopolymerizable compound and a photopolymerization initiator onto a release film and photocuring the composition.
< Photocurable adhesive composition >
(Polymer)
Examples of the polymer contained in the photocurable adhesive composition include: and rubbers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate/vinyl chloride copolymers, modified polyolefins, epoxies, fluorines, natural rubbers, and synthetic rubbers. In particular, an acrylic polymer can be suitably used from the viewpoint of exhibiting appropriate adhesion properties such as wettability, aggregability and adhesiveness and also having excellent weather resistance, heat resistance and the like.
The acrylic polymer contains an alkyl (meth) acrylate as a main constituent monomer component. In the present specification, "(meth) acrylic acid" means acrylic acid and/or methacrylic acid. The amount of the alkyl (meth) acrylate based on the total amount of the monomer components constituting the acrylic polymer is preferably 50% by weight or more, more preferably 55% by weight or more, and still more preferably 60% by weight or more.
As the alkyl (meth) acrylate, an alkyl (meth) acrylate in which the carbon number of the alkyl group is 1 to 20 can be suitably used. The alkyl group of the alkyl (meth) acrylate may have a branch or may have a cyclic alkyl group.
Specific examples of the alkyl (meth) acrylate having a chain alkyl group include: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-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, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, isotetradecyl (meth) acrylate, pentadecyl (meth) acrylate, cetyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, and the like. Preferred examples of the alkyl (meth) acrylate having a chain alkyl group used in the first embodiment include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octadecyl (meth) acrylate, and dodecyl (meth) acrylate. The amount of the alkyl (meth) acrylate having a chain alkyl group is, for example, about 40 to 90% by weight, and may be 45 to 80% by weight or 50 to 70% by weight, based on the total amount of the monomer components constituting the acrylic polymer.
Specific examples of the alkyl (meth) acrylate having an alicyclic alkyl group include: cycloalkyl (meth) acrylates such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth) acrylate; a (meth) acrylate having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth) acrylate; (meth) acrylic esters having an aliphatic hydrocarbon ring having at least three rings, such as dicyclopentyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, tricyclopentyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate. As the alkyl (meth) acrylate having an alicyclic alkyl group, which is preferably used in the first embodiment, there are cyclohexyl (meth) acrylate and isobornyl (meth) acrylate. The amount of the alkyl (meth) acrylate having an alicyclic alkyl group relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be about 5 to 40% by weight or about 10 to 30% by weight.
The acrylic polymer may contain, as a constituent monomer component, a polar group-containing monomer such as a hydroxyl group-containing monomer, a carboxyl group-containing monomer, or a nitrogen-containing monomer. When the acrylic polymer contains a polar group-containing monomer as a constituent monomer component, the cohesive force and adhesive force of the pressure-sensitive adhesive tend 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 the polar group-containing monomer (the sum of the hydroxyl group-containing monomer, the carboxyl group-containing monomer and the nitrogen-containing monomer) relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be about 5 to 40% by weight or 10 to 30% by weight.
Examples of the hydroxyl group-containing monomer include: (meth) acrylic esters such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate. In the case of introducing a crosslinked structure into a polymer by an isocyanate crosslinking agent, a hydroxyl group may constitute a reaction site (crosslinking point) with an isocyanate group. Preferred hydroxyl group-containing monomers for use in the first embodiment include: 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate. The amount of the hydroxyl group-containing monomer relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.
Examples of the carboxyl group-containing monomer include: acrylic monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, and carboxypentyl (meth) acrylate, and itaconic acid, maleic acid, fumaric acid, and crotonic acid. When a crosslinked structure is introduced into a polymer by an epoxy crosslinking agent, a carboxyl group may constitute a reactive site (crosslinking point) with an epoxy group. As a preferred carboxyl group-containing monomer used in the first embodiment, there is (meth) acrylic acid. The amount of the carboxyl group-containing monomer relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.
Examples of the nitrogen-containing monomer include: vinyl monomers such as N-vinylpyrrolidone, methyl vinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth) acryloylmorpholine, N-vinylcarboxylic acid amides, N-vinylcaprolactam and acrylamide, and cyano group-containing monomers such as acrylonitrile and methacrylonitrile. A preferred nitrogen-containing monomer for use in the first embodiment is N-vinylpyrrolidone. The amount of the nitrogen-containing monomer relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.
The acrylic polymer may contain, as monomer components (sometimes referred to as "other monomers") other than the above: vinyl monomers such as acid anhydride group-containing monomers, caprolactone adducts of (meth) acrylic acid, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, vinyl acetate, vinyl propionate, styrene, and α -methylstyrene; epoxy group-containing monomers such as glycidyl (meth) acrylate; glycol acrylate monomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxy ethylene glycol (meth) acrylate, and methoxy polypropylene glycol (meth) acrylate; acrylic ester monomers such as tetrahydrofurfuryl (meth) acrylate, fluoro (meth) acrylate, silicone (meth) acrylate, and 2-methoxyethyl (meth) acrylate.
The glass transition temperature (Tg) of the polymer contained in the photocurable adhesive composition is preferably 0 ℃ or lower. The glass transition temperature of the polymer may be below-5 ℃ and below-10 ℃ or below-15 ℃. The glass transition temperature of the polymer is the peak top temperature of the loss tangent (tan δ) based on the dynamic viscoelasticity measurement. When a crosslinked structure is introduced into the polymer, the glass transition temperature may be calculated based on the theoretical Tg from the composition of the polymer. The theoretical Tg is calculated by the Fox equation described later.
The polymer can be obtained by polymerizing the above monomer components by various known methods. The polymerization method is not particularly limited, and the polymer is preferably produced by photopolymerization. Since photopolymerization enables the production of a polymer without using a solvent, it is not necessary to dry and remove the solvent when forming an adhesive layer, and an adhesive layer having a large thickness can be uniformly formed.
In the production of the pressure-sensitive adhesive layer of the first embodiment, it is preferable to produce the pressure-sensitive adhesive layer as a polymer (prepolymer) having a low degree of polymerization in which a part of the monomer component remains unreacted. The composition for preparing a prepolymer (prepolymer-forming composition) preferably further contains a photopolymerization initiator in addition to the monomer. The photopolymerization initiator may be appropriately selected depending on the kind of the monomer. For example, a photo radical polymerization initiator may be used for polymerization of the acrylic polymer. Examples of the photopolymerization initiator include: benzoin ether type photopolymerization initiator, acetophenone type photopolymerization initiator, α -ketol type photopolymerization initiator, aromatic sulfonyl chloride type photopolymerization initiator, photoactive oxime type photopolymerization initiator, benzoin type photopolymerization initiator, benzil type photopolymerization initiator, benzophenone type photopolymerization initiator, ketal type photopolymerization initiator, thioxanthone type photopolymerization initiator, acylphosphine oxide type photopolymerization initiator, and the like.
In the polymerization, a chain transfer agent, a polymerization inhibitor (polymerization retarder), or the like may be used for the purpose of molecular weight adjustment or the like. Examples of the chain transfer agent include: thiols such as α -thioglycerol, lauryl thiol, glycidyl thiol, thioglycolic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2, 3-dimercapto-1-propanol, and α -methylstyrene dimer.
The polymerization rate of the prepolymer is not particularly limited, but is preferably 3 to 50% by weight, more preferably 5 to 40% by weight, from the viewpoint of forming a viscosity suitable for coating on a substrate. The polymerization rate of the prepolymer can be adjusted to a desired range by adjusting the type and amount of the photopolymerization initiator, the irradiation intensity/irradiation time of the active light such as UV light, and the like. The polymerization ratio of the prepolymer was calculated from the nonvolatile content when heated at 130 ℃ for 3 hours, using the following formula. The polymerization rate (nonvolatile content) of the pressure-sensitive adhesive layer was also measured by the same method.
Polymerization rate (%) = weight after heating/weight before heating × 100
As described above, the photocurable adhesive composition for forming the adhesive layer contains a polymer, a photopolymerizable compound, and a photopolymerization initiator. For example, a photopolymerizable compound and a photopolymerization initiator are added to the prepolymer to obtain a photocurable adhesive composition. Instead of using the prepolymer, a low-molecular-weight polymer (oligomer) may be used, and a photopolymerizable compound, a photopolymerization initiator, and a colorant may be mixed with the low-molecular-weight polymer to prepare a photocurable adhesive composition.
(photopolymerizable Compound)
The photopolymerizable compound contained in the photocurable adhesive composition has 1 or more photopolymerizable functional groups in 1 molecule. The photopolymerizable functional group may be any of radical polymerizable, cationic polymerizable, and anionic polymerizable, and is preferably a radical polymerizable functional group having an unsaturated double bond (ethylenically unsaturated group) from the viewpoint of excellent reactivity.
The prepolymer contains a monomer which is not reacted with the polymer, and the unreacted monomer maintains photopolymerization. Therefore, it is not always necessary to add a photopolymerizable compound in the preparation of the photocurable adhesive composition. In the case where a photopolymerizable compound is added to the prepolymer, the photopolymerizable compound to be added may be the same as or different from the monomer used for preparing the prepolymer.
When the polymer is an acrylic polymer, the compound added as the photopolymerizable compound is preferably a monomer or oligomer having a (meth) acryloyl group as a photopolymerizable functional group, from the viewpoint of high compatibility with the polymer. The photopolymerizable compound may be a polyfunctional compound having 2 or more photopolymerizable functional groups in 1 molecule. Examples of the photopolymerizable polyfunctional compound include polyfunctional (meth) acrylates. Examples of the polyfunctional (meth) acrylate include: 2-functional (meth) acrylates such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, bisphenol a ethylene oxide-modified di (meth) acrylate, bisphenol a propylene oxide-modified di (meth) acrylate, alkanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, pentaerythritol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol di (meth) acrylate, and urethane di (meth) acrylate; 3-functional (meth) acrylates such as pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and ethoxylated isocyanuric acid tri (meth) acrylate; 4-functional (meth) acrylates such as ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, and the like; dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate, and other 5-or more-functional (meth) acrylates.
When a polyfunctional compound is used as the photopolymerizable compound, the amount of the polyfunctional compound used is preferably 10 parts by weight or less, more preferably 0.001 to 1 part by weight, and still more preferably 0.005 to 0.5 part by weight, based on 100 parts by weight of the polymer (including the prepolymer). When the amount of the polyfunctional monomer used is too large, the adhesive layer after photocuring may have low viscosity and poor adhesion. The amount of the polyfunctional compound used is 10 parts by weight or less, and may be 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight or less. The polyfunctional monomer may be used in an amount of 0, and may be used in an amount of 0.001 parts by weight or more, 0.01 parts by weight or more, or 0.1 parts by weight or more.
When a monomer for forming a prepolymer is used 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 a hydroxyl group-containing monomer is used as the photopolymerizable compound, the amount of the hydroxyl group-containing monomer used is preferably 40 parts by weight or less, more preferably 1 to 30 parts by weight, and still more preferably 5 to 20 parts by weight, based on 100 parts by weight of the polymer (including the prepolymer). The amount of the hydroxyl group-containing monomer used is 40 parts by weight or less, and may be 30 parts by weight or less and 20 parts by weight or less. The hydroxyl group-containing monomer may be used in an amount of 0 part by weight or more, 5 parts by weight or more, or 10 parts by weight or more.
(photopolymerization initiator)
The photocurable adhesive composition includes a photopolymerization initiator. The photopolymerization initiator generates radicals, acids, bases, and the like by irradiation with active light such as ultraviolet rays, and can be appropriately selected according to the kind of the photopolymerizable compound and the like. When the photopolymerizable compound is a compound having a (meth) acryloyl group (for example, a monofunctional or polyfunctional (meth) acrylate), a photoradical polymerization initiator is preferably used as the photopolymerization initiator. The photopolymerization initiator may be used alone or in combination of 2 or more.
In the case where the photopolymerization initiator used in the preparation (polymerization) of the above-mentioned polymer (including prepolymer) remains without being deactivated, the addition of the photopolymerization initiator may be omitted. In the case where a photopolymerization initiator is added to a polymer, the added photopolymerization initiator may be the same as or different from the photopolymerization initiator used for preparing the polymer.
The photopolymerization initiator contained in the photocurable adhesive composition preferably has a maximum absorption in a wavelength region where light absorption by a colorant described later is small. Specifically, the photopolymerization initiator preferably has a maximum absorption in a wavelength region of 330 to 400 nm. By making the photopolymerization initiator have the maximum absorption in the region where the light absorption by the colorant is small, the inhibition of curing by the colorant can be suppressed, and therefore the polymerization rate can be sufficiently increased by photocuring. Examples of the photo radical polymerization initiator having the maximum absorption in the wavelength range of 330 to 400nm include: hydroxyketones, benzildimethylketals, aminoketones, acylphosphine oxides, benzophenones, trichloromethyl-containing triazine derivatives, and the like.
The content of the photopolymerization initiator in the photocurable adhesive composition 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 total amount of the monomers (the monomers used for preparing the polymer and the photopolymerizable compound added to the polymer).
(coloring agent)
The photocurable adhesive composition for use in the first embodiment may contain a colorant. In particular, the photocurable adhesive composition for forming the first adhesive layer 1 preferably further contains a colorant. The photocurable adhesive composition forming the first adhesive layer 1, if containing a colorant, is preferable in the following respects: the first pressure-sensitive adhesive layer 1 has a reduced permeability to visible light, and the T is formed 1 And the aforementioned T 2 Satisfy T 1 <T 2 The scheme (2). By sealing the space between the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini/Micro LED display device) of the present embodiment with the first pressure-sensitive adhesive layer 1 having reduced transparency to visible light and imparted light-shielding properties, reflection due to the metal wiring or the like can be prevented, color mixing between the LED chips can be prevented, and the contrast of an image can be improved.
The colorant may be a dye or a pigment as long as it can be dissolved or dispersed in the photocurable adhesive composition. Dyes are preferred because they can achieve low haze with a small amount of addition and are easily distributed uniformly like pigments without sedimentation. Further, pigments are also preferable from the viewpoint of obtaining high color developability with a small amount of addition. When a pigment is used as the colorant, a pigment having low or no conductivity is preferable. When a dye is used, it is preferably used in combination with an antioxidant or the like described later.
The colorant is not particularly limited, and a colorant that absorbs visible light and has ultraviolet transparency is preferable. That is, the colorant preferably has an average transmittance at a wavelength of 330 to 400nm which is larger than an average transmittance at a wavelength of 400 to 700 nm. The colorant preferably has a maximum transmittance at a wavelength of 330 to 400nm which is greater than a maximum transmittance at a wavelength of 400 to 700 nm. The transmittance of the colorant is measured using a solution or dispersion obtained by diluting with an appropriate solvent or dispersion medium (an organic solvent having low absorption in the wavelength range of 330 to 700 nm) such as Tetrahydrofuran (THF) so that the transmittance at a wavelength of 400nm is about 50 to 60%.
Examples of the ultraviolet-transmitting black pigment having ultraviolet absorption smaller than visible light absorption include: TOKUSHIKI co, "9050BLACK", "UVBK-0001" manufactured by ltd. Examples of the ultraviolet-transmitting black dye include: ORIENT CHEMICAL INDUSTRIES CO., "SOC-L-0123" manufactured by LTD.
Carbon black and titanium black generally used as black colorants have a higher ultraviolet absorption than visible light (a lower ultraviolet transmittance than visible light transmittance). Therefore, if a colorant such as carbon black is added to a photocurable adhesive composition having sensitivity to ultraviolet rays, most of the ultraviolet rays irradiated for photocuring are absorbed by the colorant, and the amount of light absorbed by the photopolymerization initiator is small, which takes time for photocuring (the cumulative amount of irradiated light is large). In addition, when the thickness of the pressure-sensitive adhesive layer is large, since ultraviolet rays reaching the surface opposite to the light irradiation surface are small, light curing tends to be insufficient even if light irradiation is performed for a long time. In contrast, by using a colorant having a higher ultraviolet transmittance than that of visible light, the inhibition of curing by the colorant can be suppressed.
The content of the colorant in the photocurable adhesive composition for forming the first adhesive layer may be, for example, about 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the monomers, and may be appropriately set according to the kind of the colorant, the color tone of the adhesive layer, the light transmittance, and the like. The colorant may be added to the composition in the form of a solution or dispersion dissolved or dispersed in a suitable solvent.
The photocurable adhesive composition for forming the second adhesive layer preferably does not contain a colorant. When the photocurable adhesive composition forming the second adhesive layer does not contain a colorant, the transmittance of visible light is increased, and the light emission efficiency of a self-luminous display device (Mini/Micro LED display device) is improved. When the photocurable adhesive composition for forming the second adhesive layer contains a colorant, the content thereof is, for example, about 0.1 part by weight or less relative to 100 parts by weight of the total amount of the monomers. In the case where the colorant is not compounded in the photocurable adhesive composition for forming the second adhesive layer, the colorant compounded in the first adhesive layer may move to the second adhesive layer.
(silane coupling agent)
In the photocurable adhesive composition, a silane coupling agent may be contained within a range not to impair the effects of the present invention. When the photocurable adhesive composition contains a silane coupling agent, the adhesion reliability to glass (especially, the adhesion reliability to glass in a high-temperature and high-humidity environment) is improved, which is preferable.
The silane coupling agent is not particularly limited, and preferably includes: gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, N-phenyl-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane and the like. Among them, gamma-glycidoxypropyltrimethoxysilane is preferable. Further, examples of commercially available products include: the trade name "KBM-403" (manufactured by shin-Etsu chemical Co., ltd.). The silane coupling agent may be used alone or in combination of 2 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, and more preferably 0.03 to 0.5 part by weight, based on 100 parts by weight of the polymer.
(other Components)
In the first embodiment, the photocurable adhesive composition may contain components other than the polymer, the photopolymerizable compound, the photopolymerization initiator, and the colorant. For example, a chain transfer agent may be contained for the purpose of adjusting the photocuring rate or the like. Further, oligomers and tackifiers may be included for the purpose of adjusting the viscosity of the photocurable adhesive composition and the adhesive strength of the adhesive layer. As the oligomer, for example, an oligomer having a weight average molecular weight of about 1000 to 30000 can be used. As the oligomer, an acrylic oligomer is preferable in terms of excellent compatibility with an acrylic polymer. The photocurable adhesive composition may contain additives such as a plasticizer, a softening agent, a deterioration preventing agent, a filler, an antioxidant, a surfactant, and an antistatic agent.
[ second mode ]
The pressure-sensitive adhesive layer of the second embodiment is a type of pressure-sensitive adhesive layer that does not undergo photocuring, and is formed from a photocurable pressure-sensitive adhesive composition in a sheet form. Since the adhesive layer of the second embodiment contains a photopolymerizable compound in an unreacted state, the adhesive layer has photocurability.
The photocurable adhesive composition for forming the adhesive layer of the second embodiment contains a polymer, a photopolymerizable compound, and a photopolymerization initiator.
(Polymer)
As the polymer contained in the pressure-sensitive adhesive composition, various polymers can be used as in the first embodiment, and an acrylic polymer can be suitably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.
In order to introduce a crosslinked structure by a crosslinking agent described later, it is preferable that the monomer component constituting the polymer contains a hydroxyl group-containing monomer and/or a carboxyl group-containing monomer. For example, when an isocyanate-based crosslinking agent is used, a hydroxyl group-containing monomer is preferably contained as a monomer component. When an epoxy-based crosslinking agent is used, a carboxyl group-containing monomer is preferably contained as a monomer.
In the second embodiment, since the photo-curing is not performed on the substrate, a polymer having a relatively high molecular weight can be used as the polymer contained in the photo-curable adhesive composition in order to form a solid (fixed shape) adhesive layer. The weight average molecular weight of the polymer is, for example, about 10 to 200 ten thousand.
Since the high molecular weight polymer is a solid, the 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 polymerization of monomer components. The polymer solution may be prepared by dissolving a solid polymer in an organic solvent.
As the solvent for the solution polymerization, ethyl acetate, toluene or the like is generally used. The solution concentration is usually about 20 to 80% by weight. As the polymerization initiator, a thermal polymerization initiator such as an azo initiator, a peroxide initiator, and a redox initiator obtained by combining a peroxide and a reducing agent (for example, a combination of a persulfate and sodium hydrogen sulfite, or a combination of a peroxide and sodium ascorbate) is preferably used. The amount of the polymerization initiator to be used is not particularly limited, and is, for example, preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, based on 100 parts by weight of the total amount of the monomer components forming the polymer.
(photopolymerizable Compound)
In the second embodiment, the photopolymerizable compound contained in the adhesive composition may be a compound having 1 or 2 or more photopolymerizable functional groups, as described above with respect to the first embodiment.
(photopolymerization initiator)
In the second embodiment, the photopolymerization initiator contained in the adhesive composition is preferably a photopolymerization initiator having a maximum absorption in a wavelength range of 330 to 400nm, as described above with respect to the first embodiment. 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.
(coloring agent)
The binder composition used in the second embodiment may contain a colorant. In particular, the photocurable adhesive composition for forming the first adhesive layer 1 preferably further contains a colorant. The photocurable adhesive composition forming the first adhesive layer 1, if containing a colorant, is preferable in the following respects: the first pressure-sensitive adhesive layer 1 has a reduced permeability to visible light, and the T is formed 1 And the aforementioned T 2 Satisfy T 1 <T 2 The scheme (2). By encapsulating the space between the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini/Micro LED display device) of the present embodiment with the first adhesive layer 1 having reduced permeability to visible light and imparted light-shielding property, reflection due to metal wiring or the like can be prevented, color mixing between the LED chips can be prevented, and the contrast of an image can be improved.
The colorant contained in the adhesive composition used in the second embodiment is preferably such that the average transmittance at a wavelength of 330 to 400nm is larger than the average transmittance at a wavelength of 400 to 700nm, as described above with respect to the first embodiment. The colorant preferably has a maximum transmittance at a wavelength of 330 to 400nm which is greater than a maximum transmittance at a wavelength of 400 to 700 nm.
(crosslinking agent)
The adhesive composition of the second embodiment preferably contains a crosslinking agent capable of crosslinking with the polymer. Specific examples of the crosslinking agent for introducing a crosslinked structure into a polymer include: isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, metal chelate crosslinking agents, and the like. Among them, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferable because they have high reactivity with hydroxyl groups and carboxyl groups of the polymer and easily introduce a crosslinked structure. These crosslinking agents react with functional groups such as hydroxyl groups and carboxyl groups introduced into the polymer to form a crosslinked structure.
As the isocyanate-based crosslinking agent, a polyisocyanate having 2 or more isocyanate groups in 1 molecule can be 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; aromatic isocyanates such as 2, 4-tolylene diisocyanate, 4' -diphenylmethane diisocyanate, and xylylene diisocyanate; trimethylolpropane/tolylene diisocyanate trimer adducts (for example, "CORONATE L" manufactured by tokyo co., ltd.), trimethylolpropane/hexamethylene diisocyanate trimer adducts (for example, "CORONATE HL" manufactured by tokyo co., ltd.), and trimethylolpropane adducts of xylylenediisocyanate (for example, "TAKENATE D110N" manufactured by mitsui chemical corporation and isocyanurate of hexamethylene diisocyanate (for example, "CORONATE HX" manufactured by tokyo co., ltd.), and the like.
As the epoxy-based crosslinking agent, a polyfunctional epoxy compound having 2 or more epoxy groups in 1 molecule can be 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-xylylenediamine, 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, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol anhydride polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and the like. As the epoxy crosslinking agent, commercially available products such as "DENANOL" manufactured by Nagase ChemteX Corporation, "TETRAD X" and "TETRAD C" manufactured by Mitsubishi gas chemical Corporation can be used.
The amount of the crosslinking agent is about 0.01 to 5 parts by weight, may be 0.05 parts by weight or more, 0.1 parts 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, based on 100 parts by weight of the polymer.
(other Components)
The pressure-sensitive adhesive composition of the second embodiment may contain, in addition to the above components, an oligomer, an adhesion promoter, a silane coupling agent, a chain transfer agent, a plasticizer, a softening agent, a deterioration preventing agent, a filler, an antioxidant, a surfactant, an antistatic agent, and the like.
< solvent-based adhesive composition >
In the present embodiment, the first adhesive layer 1 and the second adhesive layer 2 may be adhesive layers formed of solvent-based adhesive compositions (third embodiment). The aforementioned solvent-based adhesive composition contains at least a polymer and a solvent, and may contain a crosslinking agent. That is, the solvent-based adhesive composition for forming the adhesive layer of the third embodiment contains a polymer and a solvent, and may contain a crosslinking agent as needed.
[ third mode ]
The adhesive layer of the third embodiment can be formed by applying a solvent-based adhesive composition containing a polymer and a solvent and, if necessary, a crosslinking agent to a release film and drying off the solvent.
The solvent-based adhesive composition for forming the adhesive layer of the third embodiment contains a polymer and a solvent, and if necessary, contains 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 an acrylic polymer can be suitably 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 (fixed shape) adhesive layer on a substrate, a polymer having a relatively high molecular weight can be used as a polymer contained in the solvent-based adhesive composition. The weight average molecular weight of the polymer is, for example, about 10 to 200 ten thousand.
The acrylic polymer contained in the solvent-based adhesive composition of the third embodiment may be a (meth) acrylic block copolymer. When the first pressure-sensitive adhesive layer 1 and/or the second pressure-sensitive adhesive layer 2 are formed from a solvent-based pressure-sensitive adhesive composition containing a (meth) acrylic block copolymer, the step absorption property is excellent and the workability is also excellent, and therefore, the step of a plurality of LED chips arranged on a substrate of a display panel can be sealed without leaving air bubbles and without leaving gaps, and the workability is also excellent, and therefore, the pressure-sensitive adhesive layer is less likely to bleed out from the end portions during storage.
In the present embodiment, the adhesive composition forming the first adhesive layer 1 is preferably a solvent-based adhesive composition containing a (meth) acrylic block copolymer. According to this embodiment, the first pressure-sensitive adhesive layer 1 has excellent level difference absorption and workability, and can package level differences between a plurality of LED chips, metal wirings, and the like arranged on a substrate of a display panel without leaving air bubbles and without gaps, thereby preventing color mixing between the LED chips, improving the contrast of an image, and efficiently preventing reflection due to the metal wirings and the like.
In the present embodiment, the (meth) acrylic block copolymer preferably includes: a high Tg segment having a glass transition temperature of 0 ℃ or higher and 100 ℃ or lower, and a low Tg segment having a glass transition temperature of-100 ℃ or higher and lower than 0 ℃, wherein the high Tg segment and the low Tg segment have tan delta peaks in the region of 0 ℃ or higher and the region of lower than 0 ℃.
In the present specification, the "high Tg segment having a glass transition temperature of 0 ℃ or higher and 100 ℃ or lower" is simply referred to as "high Tg segment", the "low Tg segment having a glass transition temperature of-100 ℃ or higher and lower than 0 ℃ is simply referred to as" low Tg segment ", the peak of tan δ in the region of 0 ℃ or higher is simply referred to as" high temperature region tan δ peak ", the peak of tan δ in the region of lower than 0 ℃ is simply referred to as" low temperature region tan δ peak ", the (meth) acrylic block copolymer having the high Tg segment, the low Tg segment, the high temperature region tan δ peak, and the low temperature region tan δ peak is referred to as" (meth) acrylic block copolymer a ", and the solvent-based adhesive composition containing the (meth) acrylic block copolymer a is referred to as" solvent-based adhesive composition a ".
The "segment" of the high Tg segment and the low Tg segment refers to a partial structure of each block unit constituting the (meth) acrylic block copolymer a.
The structure of the aforementioned (meth) acrylic block copolymer a may be a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. The structure of such a block copolymer may be appropriately selected depending on the physical properties of the block copolymer to be required, and a linear block copolymer is preferable from the viewpoint of cost and ease of production. The linear block copolymer may have any structure (arrangement), and is preferably selected from the group consisting of (A-B) n Type, (A-B) n A block copolymer having at least 1 structure selected from the group consisting of A type (n is an integer of 1 or more, for example, an integer of 1 to 3). In these structures, A and B represent structures composed of different monomersAnd (3) forming a chain segment. In the present 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 viewpoints of ease of production, physical properties of the solvent-based adhesive composition A, and the like, an AB type diblock copolymer represented by A-B and an ABA type triblock copolymer represented by A-B-A are preferable, and an ABA type triblock copolymer is more preferable. It is considered that the ABA type triblock copolymer can exhibit higher adhesion (adhesion) by improving the cohesive force of the block copolymer by pseudo-crosslinking between the a segments at both ends to form a crosslinked structure with a higher degree of crosslinking between the block copolymers. In the ABA type triblock copolymer, the 2a segments located at both ends may be the same as or different from each other.
When the (meth) acrylic block copolymer a is an ABA type triblock copolymer, at least one of the 2a segments and 1B segment (total 3) may be a high Tg segment, and at least the other may be a low Tg segment. From the viewpoints of ease of production, physical properties of the solvent-based adhesive composition a, and the like, an ABA type triblock copolymer having the high Tg segment as an a segment and the low Tg segment as a B segment is preferable. In this case, an ABA type triblock copolymer in which at least one of the 2a segments is a high Tg segment and the B segment is a low Tg segment is preferable, and an ABA type triblock copolymer in which all of the 2a segments are high Tg segments and the B segment is a low Tg segment is more preferable.
The glass transition temperature (Tg) of the high Tg segment constituting the (meth) acrylic block copolymer A is 0 ℃ or higher and 100 ℃ or lower, as described above. When the Tg of the high Tg segment is in this range, the following tendency is exhibited: the solvent-based adhesive composition a is easily controlled to have a high storage modulus at room temperature (25 ℃), is hard and excellent in processability, and has a significantly reduced storage modulus in a region exceeding 50 ℃, and thus becomes a high-fluidity adhesive composition. The Tg of the high Tg segment is preferably 4 ℃ or higher, more preferably 6 ℃ or higher, still more preferably 8 ℃ or higher, still more preferably 10 ℃ or higher, and particularly preferably 12 ℃ or higher, from the viewpoint of improving the processability of the solvent-based adhesive composition A at room temperature (25 ℃). On the other hand, the Tg of the high Tg segment is preferably 90 ℃ or less, more preferably 85 ℃ or less, further preferably 60 ℃ or less, further preferably 50 ℃ or less, and particularly preferably 35 ℃ or less, from the viewpoint that the storage modulus (G') of the solvent-based adhesive composition a is significantly reduced in a region exceeding 50 ℃ and high fluidity is easily formed.
The Tg of the low Tg segment constituting the (meth) acrylic block copolymer A is-100 ℃ or higher and lower than 0 ℃ as described above. By setting the glass Tg of the low Tg segment in this range, there is a tendency that: only the low Tg segment fluidizes at room temperature (25 ℃), and a suitable adhesive force can be imparted to the solvent-based adhesive composition a while ensuring processability. The Tg of the low Tg segment is preferably at least-95 ℃, more preferably at least-90 ℃, and still more preferably at least-80 ℃ from the viewpoint that the storage modulus of the solvent-based adhesive composition A is not easily lowered at room temperature (25 ℃) and the processability can be improved. On the other hand, the Tg of the low Tg segment is preferably-5 ℃ or lower, more preferably-10 ℃ or lower, still more preferably-20 ℃ or lower, still more preferably-30 ℃ or lower, and particularly preferably-40 ℃ or lower, from the viewpoint of improving the appropriate adhesive strength and processability of the solvent-based adhesive composition A at room temperature (25 ℃).
The difference between the Tg of the high Tg segment and the Tg of the low Tg segment constituting the (meth) acrylic block copolymer a (Tg of the high Tg segment-Tg of the low Tg segment) is not particularly limited, but from the viewpoint of easily controlling the storage modulus of the solvent-based adhesive composition a at room temperature (25 ℃) to be high, being hard and excellent in processability, and being an adhesive composition having a storage modulus remarkably reduced in a region exceeding 50 ℃ and having high fluidity, it is preferably 30 ℃ or more, more preferably 35 ℃ or more, more preferably 40 ℃ or more, more preferably 45 ℃ or more, further preferably 50 ℃ or more, particularly preferably 55 ℃ or more, preferably 120 ℃ or less, more preferably 115 ℃ or less, more preferably 110 ℃ or less, more preferably 105 ℃ or less, further preferably 100 ℃ or less, and particularly preferably 95 ℃ or less.
The glass transition temperatures (Tg) of the high Tg segment and the low Tg segment constituting the (meth) acrylic block copolymer a were calculated from the following Fox equation. The calculated glass transition temperature is calculated based on the kind and amount of each monomer component constituting the high Tg segment or the low Tg segment of the (meth) acrylic block copolymer a, and therefore, can be adjusted by selecting the kind and amount of the monomer component of each segment, and the like.
The calculated glass transition temperature (calculated Tg) can be calculated according to the following Fox equation [1 ].
1/calculation Tg = W1/Tg (1) + W2/Tg (2) + \8230, + Wn/Tg (n) [1]
Herein, W1, W2, \ 8230, wn represents the weight fractions (% by weight) of the monomer component (1), the monomer component (2) and the monomer component 8230constituting the copolymer, and Tg (n) represents the glass transition temperatures (in absolute temperature: K) of the homopolymers of the monomer component (1), the monomer components (2) and 8230, and the monomer component (n) represents Tg (1), tg (2) and 8230, respectively.
The glass transition temperature of the homopolymer is known in various literatures, catalogs and the like, and is described, for example, in j. Brandup, e.g., h. Immergut, e.g., grucke: polymer Handbook: JOHNWILEY & SONS, INC. For the monomers which are not described in numerical values in various documents, values measured by a conventional thermal analysis, for example, a differential thermal analysis, a dynamic viscoelasticity measurement method, and the like can be used.
The temperature range in which the high-temperature range tan δ peak of the (meth) acrylic block copolymer a appears is 0 ℃ or higher (for example, 0 ℃ or higher and 100 ℃ or lower) as described above. When the high temperature region tan δ peak is in this temperature range, the following tendency is present: the solvent-based adhesive composition a is easily controlled to have a high storage modulus at room temperature (25 ℃), is hard and excellent in processability, and has a significantly reduced storage modulus in a region exceeding 50 ℃, resulting in a high-fluidity adhesive composition. The temperature at which the tan δ peak appears in the high temperature region is preferably 3 ℃ or higher, more preferably 6 ℃ or higher, even more preferably 9 ℃ or higher, even more preferably 12 ℃ or higher, and particularly preferably 15 ℃ or higher, from the viewpoint of improving the processability of the solvent-based adhesive composition a at room temperature (25 ℃). On the other hand, the temperature at which the peak of tan δ appears in the high temperature region is preferably 90 ℃ or less, more preferably 80 ℃ or less, further preferably 70 ℃ or less, further preferably 65 ℃ or less, and particularly preferably 60 ℃ or less, from the viewpoint that the storage modulus (G') of the solvent-based adhesive composition a is significantly reduced in the region exceeding 50 ℃ and high fluidity is easily formed.
The temperature region in which the tan δ peak in the low temperature region of the (meth) acrylic block copolymer a appears is lower than 0 ℃ (for example, -100 ℃ or higher and lower than 0 ℃) as described above. By setting the low temperature region tan δ peak in this temperature range, the following tendency is present: only the low Tg segment fluidizes at room temperature (25 ℃), and a suitable adhesive force can be imparted to the solvent-based adhesive composition A while ensuring processability. The temperature at which the tan δ peak appears in the low temperature region is preferably-95 ℃ or higher, more preferably-90 ℃ or higher, even more preferably-80 ℃ or higher, and even more preferably-70 ℃ or higher, from the viewpoint that the storage modulus of the solvent-based adhesive composition a is not easily lowered at room temperature (25 ℃) and the processability can be improved. On the other hand, the temperature at which the tan δ peak appears in the low temperature region is preferably-5 ℃ or less, more preferably-10 ℃ or less, further preferably-20 ℃ or less, further preferably-30 ℃ or less, and particularly preferably-40 ℃ or less, from the viewpoint of being able to improve the appropriate adhesive strength and processability of the solvent-based adhesive composition A at room temperature (25 ℃).
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 high-temperature region tan δ peak is within this range, since the (meth) acrylic block copolymer a can achieve excellent processability and shape stability. The maximum value of the high-temperature region tan δ peak is preferably 0.6 or more, and more preferably 0.7 or more, from the viewpoint of achieving excellent workability. The maximum value of the high-temperature region tan δ peak is preferably 2.5 or less, and more preferably 2.2 or less, from the viewpoint of less susceptibility to indentation.
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 is within this range, since the (meth) acrylic block copolymer a can achieve excellent processability and shape stability. The maximum value of the high-temperature region tan δ peak is preferably 0.2 or more, and more preferably 0.3 or more, from the viewpoint of achieving excellent workability. The maximum value of the low temperature region tan δ peak is preferably 1.5 or less, and more preferably 1 or less, from the viewpoint of being less likely to cause indentation.
The high-temperature region tan δ peak and the low-temperature region tan δ peak, and the temperature and the maximum value at which these peaks appear, are measured by dynamic viscoelasticity measurement.
The (meth) acrylic block copolymer a is composed of a plurality of segments (including a high Tg segment and a low Tg segment) obtained by polymerizing a monomer component including a monomer (acrylic monomer) having a (meth) acryloyl group in the molecule.
The (meth) acrylic block copolymer a or each segment thereof preferably contains 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 90% by weight or more of an acrylic monomer with respect to the total amount (100% by weight) of the monomer components.
The acrylic monomer constituting the (meth) acrylic block copolymer a or each segment thereof (including the high Tg segment and the low Tg segment) includes, as the most major monomer units in terms of weight ratio, a monomer component derived from an alkyl acrylate having a linear or branched alkyl group and/or an alkyl methacrylate having a linear or branched alkyl group.
Specific examples of the alkyl (meth) acrylate having a linear or branched alkyl group for forming the segment of the (meth) acrylic block copolymer a include the above-mentioned alkyl (meth) acrylate having a chain alkyl group. As the alkyl (meth) acrylate used for the segment, one kind of alkyl (meth) acrylate may be used, or two or more kinds of alkyl (meth) acrylates may be used. As the alkyl (meth) acrylate used for the segment, at least one selected from the group consisting of methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, t-butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, and isononyl acrylate is preferably used.
The segment of the (meth) acrylic block copolymer a may contain a monomer unit derived from an alicyclic monomer. Specific examples of the alicyclic monomer used as the monomer unit for forming the segment include the above-mentioned alkyl (meth) acrylate 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), linear or branched alkyl groups having 1 to 6 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, etc.), and the like. The number of the substituents is not particularly limited, and may be appropriately selected from 1 to 6. When 2 or more substituents are present, the 2 or more substituents may be the same or different. As the alicyclic monomer used in the segment, one kind of alicyclic monomer may be used, or two or more kinds of alicyclic monomers may be used. The alicyclic monomer used in the segment is preferably a cycloalkyl (meth) acrylate 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), and more preferably at least one selected from the group consisting of cyclohexyl acrylate and 3, 5-trimethylcyclohexyl (meth) acrylate.
The segment of the (meth) acrylic block copolymer a may contain a monomer unit derived from a hydroxyl group-containing monomer. The hydroxyl group-containing monomer is a monomer having at least one hydroxyl group in the monomer unit. When the segment in the (meth) acrylic block copolymer a contains a hydroxyl group-containing monomer unit, adhesiveness and appropriate cohesive force are easily obtained in the solvent-based adhesive composition a.
Specific examples of the hydroxyl group-containing monomer used for the monomer unit forming the segment include the above-mentioned hydroxyl group-containing monomers. As the hydroxyl group-containing monomer used for the segment, one kind of hydroxyl group-containing monomer may be used, or two or more kinds of hydroxyl group-containing monomers may be used. The hydroxyl group-containing monomer used in the segment is preferably a hydroxyl group-containing (meth) acrylate, and more preferably at least one selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate.
The segment of the (meth) acrylic block copolymer a may contain a monomer unit derived from a nitrogen atom-containing monomer. The nitrogen atom-containing monomer is a monomer having at least one nitrogen atom in the monomer unit. When the segment of the (meth) acrylic block copolymer a contains a nitrogen atom-containing monomer unit, hardness and good adhesion reliability can be easily obtained in the solvent-based adhesive composition a.
Specific examples of the nitrogen atom-containing monomer used for forming the segment include the nitrogen atom-containing monomers described above. As the nitrogen atom-containing monomer used for the acrylic polymer, one nitrogen atom-containing monomer may be used, or two or more nitrogen atom-containing monomers may be used. As the nitrogen atom-containing monomer used for the aforementioned segment, N-vinyl-2-pyrrolidone is preferably used.
The segment of the (meth) acrylic block copolymer a may contain a monomer unit derived from a carboxyl group-containing monomer. The carboxyl group-containing monomer is a monomer having at least one carboxyl group in a 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.
Specific examples of the carboxyl group-containing monomer used for the monomer unit forming the segment include the above-mentioned carboxyl group-containing monomers. As the carboxyl group-containing monomer used in the segment, one kind of carboxyl group-containing monomer may be used, or two or more kinds of carboxyl group-containing monomers may be used. As the carboxyl group-containing monomer used for the aforementioned segment, acrylic acid is preferably used.
Further, as the monomer unit for forming the segment, the other monomers mentioned above can be mentioned. The content of the other monomer in the monomer units constituting the segment of the (meth) acrylic block copolymer a is not particularly limited as long as it is 30% by weight or less with respect to the total amount (100% by weight) of the monomer components, and may be appropriately selected within a range that does not impair the effects of the present invention.
The monomer component constituting the high Tg segment of the (meth) acrylic block copolymer a is preferably an alkyl (meth) acrylate containing a linear alkyl group having 1 to 3 carbon atoms (hereinafter, may be referred to as "C (meth) acrylate") selected from the group consisting of alkyl (meth) acrylates having a linear alkyl group having 1 to 3 carbon atoms, from the viewpoint of easily controlling the Tg of the high Tg segment within a predetermined range and imparting desired physical properties to the (meth) acrylic block copolymer a 1-3 Linear alkyl ester) ", an alkyl (meth) acrylate having a branched alkyl group having 3 or 4 carbon atoms (hereinafter, may be referred to as" (meth) acrylic acid C 3-4 Branched alkyl ester ") and an alicyclic monomer. Since homopolymers of these monomers have a relatively high Tg, it is easy to control the Tg of the high Tg segment to the range defined in the present invention by containing a monomer selected from these monomers as a monomer component constituting the high Tg segment.
The alicyclic monomer is preferably a cycloalkyl (meth) acrylate having a cycloalkyl group with 4 to 10 carbon atoms, which may have a substituent (e.g., a linear or branched alkyl group with 1 to 6 carbon atoms), more preferably a cycloalkyl acrylate having a cycloalkyl group with 4 to 10 carbon atoms, which may have a substituent (e.g., a linear or branched alkyl group with 1 to 6 carbon atoms), and particularly preferably cyclohexyl acrylate (Tg of homopolymer: 15 ℃) and 3, 5-trimethylcyclohexyl (meth) acrylate (Tg of homopolymer: 52 ℃).
When an alicyclic monomer is contained as a monomer component constituting the high Tg segment, the content of the alicyclic monomer with respect to the total amount (100 wt%) of the monomer components is preferably 10 wt% or more (for example, 10 to 100 wt%), more preferably 20 wt% or more, more preferably 30 wt% or more, more preferably 40 wt% or more, more preferably 50 wt% or more, more preferably 60 wt% or more, more preferably 70 wt% or more, more preferably 80 wt% or more, further preferably 90 wt% or more, and particularly preferably 95 wt% or more, from the viewpoint of easily controlling the Tg of the high Tg segment within a predetermined range and of imparting desired physical properties to the (meth) acrylic block copolymer a.
As the aforementioned (meth) acrylic acid C 1-3 Straight chain alkyl esters, preferably acrylic acid C 1-3 The linear alkyl ester is particularly preferably methyl acrylate (Tg of the homopolymer: 8 ℃ C.).
As the aforementioned (meth) acrylic acid C 3-4 Branched alkyl esters, preferably C acrylic acid 3-4 The branched alkyl ester is particularly preferably t-butyl acrylate (Tg of homopolymer: 35 ℃ C.).
Containing (meth) acrylic acid C as a monomer component constituting the high Tg segment 1-3 Linear alkyl ester and/or (meth) acrylic acid C 3-4 In the case of a branched alkyl ester, the (meth) acrylic acid C 1-3 Linear alkyl ester and/or (meth) acrylic acid C 3-4 The content of the branched alkyl ester relative to the total amount (100% by weight) of the monomer components is 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 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, further preferably 90% by weight or more, and particularly preferably 95% by weight or more, from the viewpoint of easily controlling Tg of the high Tg segment within a predetermined range and of being able to impart desired physical properties to the (meth) acrylic block copolymer a.
The monomer component constituting the low Tg segment of the (meth) acrylic block copolymer a is preferably an alkyl (meth) acrylate containing a linear or branched alkyl group having 4 to 18 carbon atoms (hereinafter, may be referred to as "C (meth) acrylate"), from the viewpoint of easily controlling the Tg of the low Tg segment in a predetermined range and of imparting desired physical properties to the (meth) acrylic block copolymer a 4-18 Alkyl ester ") and hydroxyl group-containing monomers. Namely, (meth) acrylic acid C 4-18 Since the homopolymer of the alkyl ester has a low Tg, the Tg of the low Tg segment can be easily controlled within the range defined in the present invention by containing the homopolymer as a monomer component constituting the low Tg segment. On the other hand, hydroxyl group-containing monomers are also preferredA low Tg, and furthermore, adhesiveness and appropriate cohesive force are easily obtained in the (meth) acrylic block copolymer a. Therefore, it is more preferable that the monomer component constituting the low Tg segment of the (meth) acrylic block copolymer a further contains (meth) acrylic acid C 4-18 Both alkyl esters and hydroxyl-containing monomers.
As the aforementioned (meth) acrylic acid C 4-18 Alkyl esters, preferably acrylic acid C 4-18 Alkyl esters, particularly preferably butyl acrylate (homopolymer Tg: -55 ℃ C.), 2-ethylhexyl acrylate (homopolymer Tg: -70 ℃ C.), n-hexyl acrylate (homopolymer Tg: -57 ℃ C.), n-octyl acrylate (homopolymer Tg: -65 ℃ C.), isononyl acrylate (homopolymer Tg: -58 ℃ C.).
Containing (meth) acrylic acid C as a monomer component constituting the low Tg segment 4-18 In the case of alkyl esters, with respect to (meth) acrylic acid C 4-18 The content of the alkyl ester relative to the total amount (100% by weight) of the monomer components is 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 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, further preferably 90% by weight or more, and particularly preferably 95% by weight or more, 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.
As the hydroxyl group-containing monomer, a hydroxyl group-containing alkyl (meth) acrylate is preferable, and 4-hydroxybutyl acrylate (homopolymer Tg: -65 ℃ C.) and 2-hydroxyethyl acrylate (homopolymer Tg: -15 ℃ C.) are particularly preferable.
When the hydroxyl group-containing monomer is contained as the monomer component constituting the low Tg segment, the content of the hydroxyl group-containing monomer relative to the total amount (100% by weight) of the monomer components is preferably 1% by weight or more, more preferably 1.5% by weight or more, more preferably 2% by weight or more, further preferably 2.5% by weight or more, and particularly preferably 3% by weight or more, 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. On the other hand, the content of the hydroxyl group-containing monomer with respect to the total amount (100% by weight) of the monomer components is preferably 50% by weight or less, more preferably 40% by weight or less, more preferably 30% by weight or less, more preferably 20% by weight or less, further preferably 10% by weight or less, and particularly preferably 5% by weight or less.
The (meth) acrylic block copolymer A contains a (meth) acrylic acid C as a monomer component constituting the low Tg segment 4-18 In the case of both the alkyl ester and the hydroxyl group-containing monomer, the hydroxyl group-containing monomer and (meth) acrylic acid C 4-18 Ratio of alkyl esters (hydroxyl group-containing monomer/(meth) acrylic acid C) 4-18 Alkyl ester), 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, and the upper limit is preferably 50/50, more preferably 40/60, more preferably 30/70, further preferably 20/80.
The (meth) acrylic block copolymer a can be produced by a living radical polymerization method of the monomer components. The living radical polymerization method is preferable in the following respects: while maintaining the simplicity and versatility of conventional radical polymerization methods, termination reactions and chain transfer do not easily occur, and the growth proceeds without deactivation of the growing end, so that it is easy to precisely control the molecular weight distribution and to produce a polymer having a uniform composition.
In the living radical polymerization method, a high Tg segment can be prepared first, and then a monomer of a low Tg segment is polymerized with the high Tg segment; alternatively, the low Tg segment may be made and then the monomers of the high Tg segment may be polymerized with the low Tg segment.
When the (meth) acrylic block copolymer a is an ABA type triblock copolymer, it is preferable to first produce an a segment and then polymerize a monomer of a B segment with the a segment from the viewpoint of ease of production.
The living radical polymerization method may be any known method without particular limitation, and there are, depending on the method for stabilizing the polymerization growth end: a method using a transition metal catalyst (ATRP method); a method (RAFT method) using a sulfur-based reversible addition-fragmentation chain transfer agent (RAFT agent); a method using an organotellurium compound (TERP method), and the like. Among these methods, the RAFT method is preferably used from the viewpoint of the variety of monomers that can be used, the ease of molecular weight control, the absence of metal residues in the solvent-based adhesive composition, and the like.
The RAFT method may be any known method without particular limitation, and includes, for example, the following steps: step 1, for example, preparing a first segment by polymerizing a monomer component using a RAFT agent (first RAFT polymerization); and a step 2 of adding/polymerizing a monomer component having a different monomer composition from that in the step 1 to the first segment obtained in the step 1, and adding a second segment to the first segment (second RAFT polymerization). After the second RAFT polymerization, RAFT polymerization of 3 rd and 4 th\8230canbe carried out in the same manner as the second RAFT polymerization, and the segment of 3 rd and 4 th \8230canbe further added.
The steps 1 and 2 can be carried out by a known and conventional method, and examples thereof include: a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method by heat or irradiation with active energy rays (a thermal polymerization method, an active energy ray polymerization method), and the like. Among them, the solution polymerization method is preferable in terms of transparency, water resistance, cost, and the like. In view of suppressing polymerization inhibition by oxygen, it is preferable to carry out the polymerization while avoiding contact with 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 the step 1 and add a B segment to the obtained a segment in the step 2. In this case, the high Tg segment is preferably an A segment, and the low Tg segment is preferably a B segment.
The RAFT agent may be a known RAFT agent without any particular limitation, and is preferably a compound (trithiocarbonate, dithioester, dithiocarbonate) represented by, for example, the following formula (1), formula (2), or formula (3).
Figure BDA0003872505190000431
Formula (1), formula (2), or formula (3) [ formulae (1) to (3) ]]In, R 1a And R 1b The same or different, represents a hydrogen atom, a hydrocarbon group or a cyano group. R 1c Represents a hydrocarbon group optionally having a cyano group. With respect to as the above R 1a 、R 1b And R 1c Examples of the hydrocarbon group(s) include hydrocarbon groups having 1 to 20 carbon atoms (e.g., linear, branched or cyclic saturated or unsaturated hydrocarbon groups), and among them, hydrocarbon groups having 1 to 12 carbon atoms are preferable. Specific examples of the hydrocarbon group include: a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a cyclohexyl group, a dodecyl group, an octadecyl group, etc.; aryl groups having 6 to 12 carbon atoms such as phenyl groups; and arylalkyl groups having 7 to 10 total carbon atoms such as benzyl and phenethyl. With respect to as the above R 1c Examples of the hydrocarbon group having a cyano group include those in which 1 to 3 hydrogen atoms of the hydrocarbon group are substituted with a cyano group.
In the formulae (1) to (3), R 2 The term "hydrocarbyl" refers to a hydrocarbyl group or a group in which a part of the hydrogen atoms of the hydrocarbyl group have been replaced with carboxyl groups (e.g., carboxyalkyl groups). Examples of the hydrocarbon group include hydrocarbon groups having 1 to 20 carbon atoms (linear, branched or cyclic saturated or unsaturated hydrocarbon groups, etc.), and among them, hydrocarbon groups having 1 to 12 carbon atoms are preferable. Specific examples of the hydrocarbon group include: a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a cyclohexyl group, a dodecyl group, an octadecyl group, etc.; and arylalkyl groups having 7 to 10 total carbon atoms such as benzyl and phenethyl.
The RAFT method is a method in which a raw material monomer is polymerized by a reaction between a sulfur atom in a RAFT agent represented by (1) to (3) and a methylene group adjacent to the sulfur atom.
Most of the aforementioned RAFT agents are commercially available. Commercially unavailable can be readily synthesized using well-known and conventional methods. In the present invention, 1 RAFT agent may be used alone, or 2 or more RAFT agents may be used in combination.
Examples of RAFT agents include: trithiocarbonates such as dibenzyltrithiocarbonate and S-cyanomethyl-S-dodecyl trithiocarbonate; dithioesters such as cyanoethyl dithiopropionate, benzyl dithiobenzoate, and acetoxyethyl dithiobenzoate; dithiocarbonates such as O-ethyl-S- (1-phenylethyl) dithiocarbonate, O-ethyl-S- (2-propoxyethyl) dithiocarbonate, and O-ethyl-S- (1-cyano-1-methylethyl) dithiocarbonate are preferred, of which trithiocarbonates are more preferred, trithiocarbonates having a structure symmetrical to the left and right in formula (1) are still more preferred, and dibenzyl trithiocarbonate and bis {4- [ ethyl- (2-acetoxyethyl) carbamoyl ] benzyl } trithiocarbonate are particularly preferred.
The step 1 may be carried out by polymerizing the monomer component in the presence of a RAFT agent. The amount of the RAFT agent used in step 1 is usually 0.05 to 20 parts by weight, preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the total amount of the monomer components. When the amount is such an amount, the reaction can be easily controlled, and the weight average molecular weight of the obtained segment can be easily controlled.
The step 2 may be performed by adding a monomer component to the polymerization reaction mixture obtained in the step 1 and further polymerizing the mixture.
The RAFT process is preferably carried out in the presence of a polymerisation initiator. Examples of the polymerization initiator include common organic polymerization initiators, specifically peroxides and azo compounds, and among these, azo compounds are preferred. The polymerization initiator may be used alone in 1 kind or in 2 or more kinds.
Examples of the peroxide-based polymerization initiator include: benzoyl peroxide and tert-butyl peroxymaleate.
Examples of the azo compound include: 2,2 '-azobisisobutyronitrile, 2' -azobis (4-methoxy-2, 4-dimethylvaleronitrile), 2 '-azobis (2-cyclopropylpropionitrile), 2' -azobis (2, 4-dimethylvaleronitrile), 2 '-azobis (2-methylbutyronitrile) 1,1' -azobis (cyclohexane-1-carbonitrile), 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy-2, 4-dimethylvaleronitrile, 2 '-azobis (2-amidinopropane) dihydrochloride, 2' -azobis (N, N '-dimethyleneisobutylamidine), 2' -azobis (isobutylamide) dihydrate, 4 '-azobis (4-cyanopentanoic acid), 2' -azobis (2-cyanopropanol), dimethyl-2, 2 '-azobis (2-methylpropionate), 2' -azobis [ 2-methyl-N- (2-hydroxyethyl) propionamide ].
The amount of the polymerization initiator to be used is usually 0.001 to 2 parts by weight, preferably 0.002 to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components. If it is used in such an amount, the weight average molecular weight of the resulting segment can be easily controlled.
The RAFT method may be bulk polymerization without using a polymerization solvent, but preferably uses 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; alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1, 2-dichloroethane, chlorobenzene, and the like; ethers such as diethyl ether, diisopropyl ether, 1, 2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenetole, and diphenyl ether; esters such as ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethyl sulfoxide and sulfolane. The polymerization solvent may be used alone in 1 kind or in 2 or more kinds.
The amount of the polymerization solvent to be used is not particularly limited, and is, for example, preferably 0.01mL or more, more preferably 0.05mL or more, further preferably 0.1mL or more, preferably 50mL or less, more preferably 10mL or less, and further preferably 1mL or less, relative to 1g of the monomer component.
The reaction temperature in the RAFT method is usually 60 to 120 ℃, preferably 70 to 110 ℃, and is usually carried out in an inert gas atmosphere such as nitrogen. The reaction can be carried out under any of normal pressure, increased pressure and reduced pressure, and is usually carried out under normal pressure. The reaction time is usually 1 to 20 hours, preferably 2 to 14 hours.
The polymerization conditions of the RAFT method can be applied to step 1 and step 2, respectively.
After the polymerization reaction is completed, the desired (meth) acrylic block copolymer a can be isolated from the obtained reaction mixture by a common separation and purification means, for example, by using a solvent or removing residual monomers.
When the high Tg segment or the low Tg segment of the (meth) acrylic block copolymer a is produced in the step 1, the weight average molecular weight (Mw) of the high Tg segment or the low Tg segment is not particularly limited, but is preferably 10,000 to 1,000,000, more preferably 50,000 to 500,000, and further preferably 100,000 to 300,000. An Mw of the high Tg segment or the low Tg segment within this range is suitable for the above-described effects of the present invention.
When two or more high Tg segments or low Tg segments are present in the (meth) acrylic block copolymer a, the Mw is the sum of these Mw.
The weight average molecular weight (Mw) of the (meth) acrylic block copolymer a is not particularly limited, but is preferably 20 ten thousand (200,000) or more, more preferably 300,000 to 5,000,000, and still more preferably 400,000 to 2,500,000. An Mw of the (meth) acrylic block copolymer A within this range is suitable 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 greater than 1, more preferably 1.5 or more, further preferably 2 or more, particularly preferably 2.5 or more, preferably 5 or less, more preferably 4.5 or less, further preferably 4 or less, and particularly preferably 3.5 or less.
The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) were measured by GPC.
The content of the high Tg segment in the (meth) acrylic block copolymer a is preferably 10 wt% or more, more preferably 20 wt% or more, further preferably 25 wt% or more, particularly preferably 30 wt% or more, preferably 95 wt% or less, more preferably 90 wt% or less, further preferably 85 wt% or less, of the total 100 wt% of the (meth) acrylic block copolymer a.
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, further preferably 15% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, further preferably 40% by weight or less, and particularly preferably 30% by weight or less, of the total 100% by weight of the (meth) acrylic block copolymer a.
The content of each segment and the ratio thereof can be calculated from the weight average molecular weight (Mw) of each segment obtained in each step of the RAFT method or the (meth) acrylic block copolymer a, and can be controlled by the addition ratio of the monomers at the time of forming each segment, the polymerization ratio of each monomer, and the like.
The content of the (meth) acrylic block copolymer a in the solvent-based adhesive composition a is not particularly limited, and is preferably 50% by weight or more (for example, 50 to 100% by weight), more preferably 60% by weight or more, further preferably 80% by weight or more, and particularly preferably 90% by weight or more, relative to the total amount (total weight, 100% by weight) of the solvent-based adhesive composition a, from the viewpoint of obtaining excellent processability at room temperature (25 ℃) and excellent level difference absorption in a region exceeding 50 ℃.
(solvent)
Since the polymer in the third embodiment 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 polymerization of a monomer component. The polymer solution may be prepared by dissolving a solid polymer in an organic solvent.
As the solvent, ethyl acetate, toluene, or the like is generally used. The concentration of the solution is usually about 20 to 80% by weight.
As the polymerization initiator for solution polymerization of the monomer component, a thermal polymerization initiator such as an azo initiator, a peroxide initiator, and a redox initiator obtained by combining a peroxide and a reducing agent (for example, a combination of a persulfate and sodium hydrogen sulfite, or a combination of a peroxide and sodium ascorbate) is preferably used. The amount of the polymerization initiator to be used is not particularly limited, and is, for example, preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, based on 100 parts by weight of the total amount of the monomer components forming the polymer.
(coloring agent)
The solvent-based adhesive composition used to form the adhesive layer of the third embodiment may contain a colorant. In particular, the solvent-based adhesive composition for forming the first adhesive layer 1 preferably further contains a colorant. If the solvent-based adhesive composition forming the first adhesive layer 1 contains a colorant, it is preferable in the following respects: the first pressure-sensitive adhesive layer 1 has a reduced transmittance for visible light, and the T is formed 1 And the aforementioned T 2 Satisfy T 1 <T 2 The scheme (2). By encapsulating the space between the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini/Micro LED display device) of the present embodiment with the first adhesive layer 1 having reduced permeability to visible light and imparted light-shielding property, reflection due to metal wiring or the like can be prevented, color mixing between the LED chips can be prevented, and the contrast of an image can be improved.
The colorant may be a dye or a pigment as long as it is soluble or dispersible in the solvent-based adhesive composition. Dyes are preferred because they can achieve low haze with a small amount of addition and are easily distributed uniformly like pigments without sedimentation. Further, pigments are also preferable from the viewpoint of obtaining high color developability with a small amount of addition. When a pigment is used as the colorant, a pigment having low or no conductivity is preferable. When a dye is used, it is preferably used in combination with an antioxidant or the like described later.
In the third aspect, the colorant contained in the solvent-based adhesive composition further includes an ultraviolet absorbing colorant in addition to the ultraviolet-transmitting colorant described above with respect to the first aspect.
Examples of the ultraviolet-transmitting black pigment include: TOKUSHIKI co, "9050BLACK", "UVBK-0001" manufactured by ltd. Examples of the ultraviolet-absorbing black dye include: ORIENT CHEMICAL INDUSTRIES CO., LTD. "VALIFAST BLACK3810", "NUBIAN Black PA-2802", and the like. Examples of the ultraviolet-absorbing black pigment include: carbon black, titanium black, and the like.
The content of the colorant in the solvent-based adhesive composition may be, for example, about 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the monomers, and may be appropriately set depending on the kind of the colorant, the color tone of the adhesive layer, the light transmittance, and the like. 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 adhesive composition of the third embodiment may contain a crosslinking agent capable of crosslinking with the above-mentioned polymer. When the solvent-based adhesive composition contains a (meth) acrylic block copolymer, the adhesive layer of the third embodiment may contain no crosslinking agent because the adhesive layer has sufficient shape stability.
In the third aspect, when the solvent-based adhesive composition contains a crosslinking agent, the crosslinking agent is preferably an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent, as described above with respect to the second aspect.
In the third aspect, when the solvent-based adhesive composition contains the crosslinking agent, the content thereof may be about 0.01 to 5 parts by weight, 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more, and 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less, relative to 100 parts by weight of the polymer.
(other Components)
The solvent-based adhesive composition according to the third embodiment may contain, in addition to the above components, an oligomer, an adhesion promoter, a silane coupling agent, a chain transfer agent, a plasticizer, a softening agent, a deterioration preventing agent, a filler, an antioxidant, a surfactant, an antistatic agent, and the like.
< optical layered body >
In the present embodiment, the optical layered bodies 10 to 12 can be prepared by laminating the second adhesive layer 2 on the surface 3b of the substrate 3 and further laminating the first adhesive layer 1.
[ first mode ]
The method for laminating the second pressure-sensitive adhesive layer 2 of the first embodiment on the surface 3b of the substrate 3 is not particularly limited, and for example, the method can be performed by applying the photocurable pressure-sensitive adhesive composition to a release film, molding the composition into a sheet form, photocuring the sheet form to produce the second pressure-sensitive adhesive layer 2 in a sheet form, and then bonding the sheet form to the surface 3b of the substrate 3.
The method of further laminating the first pressure-sensitive adhesive layer 1 on the second pressure-sensitive adhesive layer 2 laminated on the substrate 3 is not particularly limited, and for example, the method can be performed by applying the photocurable pressure-sensitive adhesive composition on a release film, molding the composition into a sheet form, photocuring the sheet form to prepare the sheet-form first pressure-sensitive adhesive layer 1, and then bonding the sheet-form first pressure-sensitive adhesive layer 1 to the second pressure-sensitive adhesive layer laminated on the surface 3b of the substrate 3.
The first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer of the first embodiment can be obtained by applying a photocurable pressure-sensitive adhesive composition in a sheet form (layer form) on a release film, and irradiating ultraviolet rays onto the coating film of the pressure-sensitive adhesive composition on the release film to effect photocuring. In the case of photocuring, it is preferable to further provide a release film on the surface of the coating film, and irradiate the photocurable adhesive composition with ultraviolet light in a state of being sandwiched between 2 release films to prevent inhibition of polymerization by oxygen. The sheet-like coating film may be heated before photocuring for the purpose of, for example, removing a solvent or a dispersion medium for the colorant. When the solvent or the like is removed by heating, it is preferably performed before the release film is attached.
As the film base material of the release film, films formed of various resin materials can be used. As the resin material, there can be mentioned: polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, polyphenylene sulfide resins, and the like. Among these, polyester resins such as polyethylene terephthalate are particularly preferable. The thickness of the film substrate is preferably 10 to 200. Mu.m, more preferably 25 to 150. Mu.m. Examples of the material of the release layer include: silicone release agents, fluorine release agents, long-chain alkyl release agents, fatty acid amide release agents, and the like. The thickness of the release layer is generally about 10 to 2000 nm.
As a method for coating the adhesive composition on the release film, various methods such as roll coating, roll-lick coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, blade coating, air knife coating, curtain coating, lip coating, die coater, and the like can be used.
The thickness of the first pressure-sensitive adhesive layer 1 is not particularly limited, and may be appropriately set so that the upper portion (image display side) of the light-emitting element is covered with the second pressure-sensitive adhesive layer 2 while the light-emitting element arranged on a display panel described later is sufficiently sealed. For example, the thickness of the first pressure-sensitive adhesive layer is adjusted to be 0.1 to 2.0 times, preferably 0.2 to 1.5 times, and more preferably 0.3 to 1.2 times the height of the light-emitting element. Specifically, the thickness of the first pressure-sensitive adhesive layer is, for example, about 10 to 300. Mu.m, preferably 15 to 200. Mu.m. Specifically, the thickness of the first pressure-sensitive adhesive layer may be 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. In addition, in the case where the first adhesive layer contains an ultraviolet-permeable colorant, even when the thickness of the first adhesive layer is large, the photocurable adhesive composition can be uniformly photocured in the thickness direction. The thickness of the first adhesive layer is 300 μm or less, and may be 250 μm or less or 200 μm or less.
The thickness of the second pressure-sensitive adhesive layer 2 is not particularly limited, and may be appropriately set so as to sufficiently encapsulate light-emitting elements arranged on a display panel described later and sufficiently transmit light above the light-emitting elements (on the image display side). Specifically, the thickness of the second pressure-sensitive adhesive layer is, for example, about 1 to 500. Mu.m, more preferably 10 to 300. Mu.m, and still more preferably 15 to 200. Mu.m. Specifically, the thickness of the second pressure-sensitive adhesive layer may be 1 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. The thickness of the second adhesive layer may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less.
The total thickness of the first adhesive layer 1 and the second adhesive layer 2 is not particularly limited, and may be appropriately set so that the light-emitting elements arranged on a display panel described later can be sufficiently sealed and the height of the light-emitting elements is not less than the height of the light-emitting elements. For example, the thickness of the pressure-sensitive adhesive layer is adjusted to be 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2.5 times, and still more preferably 1.3 to 2.0 times the height of the light-emitting element. Specifically, the total thickness of the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 is, for example, about 11 to 800 μm, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. The total thickness of the first adhesive layer 1 and the second adhesive layer 2 is, for example, 700 μm or less, and may be 600 μm or less, 500 μm or less, or 400 μm or less.
The ratio of the thickness of the second pressure-sensitive adhesive layer to the thickness of the first pressure-sensitive adhesive layer (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is not particularly limited, and may be appropriately set so that the light-emitting elements arranged on a display panel described later are sufficiently sealed and the upper portions (image display side) of the light-emitting elements are covered with the second pressure-sensitive adhesive layer. Specifically, the thickness of the (second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) may be, for example, about 1.0 to 5.0, preferably 1.2 to 4.0, and more preferably 1.3 to 3.0.
When the photocurable adhesive composition applied in a layer form on the release film is irradiated with ultraviolet rays, active species are generated from the photopolymerization initiator, and the photopolymerizable compound is polymerized, whereby the liquid photocurable adhesive composition forms a solid (predetermined shape) adhesive layer with an increase in polymerization rate (decrease in unreacted monomer). The light source used for ultraviolet irradiation is not particularly limited as long as it can irradiate light in a wavelength range in which the photopolymerization initiator contained in the photocurable adhesive composition has sensitivity, and an LED light source, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like can be used.
The cumulative light amount of the irradiation light is, for example, 100 to 5000mJ/cm 2 Left and right. The polymerization ratio (nonvolatile content) of the pressure-sensitive adhesive layer formed from a photocurable product of the photocurable pressure-sensitive adhesive composition is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. The polymerization rate may be 93% or more or 95% or more. In order to reduce the nonvolatile components, the pressure-sensitive adhesive layer may be heated to remove volatile components such as residual monomers, unreacted polymerization initiator, and solvent.
When release films are provided on both sides of the pressure-sensitive adhesive layer, the thickness of one release film may be the same as or different from that of the other release film. The peeling force at the time of peeling the peeling film temporarily bonded to one surface from the adhesive layer may be the same as or different from the peeling force at the time of peeling the peeling film temporarily bonded to the other surface from the adhesive layer. When the two are different in peel force, the release film (light release film) having a relatively small peel force is peeled off from the second pressure-sensitive adhesive layer 2 to bond the second pressure-sensitive adhesive layer 2 to the surface 3b of the substrate 3, and then the release film (heavy release film) having a relatively large peel force is peeled off from the second pressure-sensitive adhesive layer 2 to expose the second pressure-sensitive adhesive layer. Then, the light release film is peeled off from the first pressure-sensitive adhesive layer 1, and the first pressure-sensitive adhesive layer 1 is attached to the exposed second pressure-sensitive adhesive layer, whereby an optical laminate having the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first embodiment can be produced.
An optical laminate having the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first embodiment can also be produced in the same manner as described above, except that the photocurable pressure-sensitive adhesive composition is applied to the surface 3b of the substrate 3, formed into a sheet, and then a release film is attached to the surface of the coating film, and the second pressure-sensitive adhesive layer is laminated on the substrate 3 by irradiation with ultraviolet light.
In the case where a colorant is contained in the first adhesive layer and/or the second adhesive layer, light absorption is provided for visible light. The optical laminate of the first embodiment may have a visible light transmittance of, for example, 80% or less, and may have a visible light transmittance of 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 aspect, the visible light transmittance T to the first pressure-sensitive adhesive layer 1 The content is not particularly limited, and may be, for example, 80% or less, or 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less. By making the visible light transmittance T of the first adhesive layer 1 80% or less, and easily has a lower transmittance than the visible light transmittance T of the second pressure-sensitive adhesive layer 2 As described above, by encapsulating between the metal wiring and the light emitting element of the self-luminous display device, reflection of the metal wiring and the like can be prevented, color mixing between the light emitting elements can be prevented, and contrast can be improved. Further, as described above, when a colorant having an absorption of ultraviolet rays smaller than that of visible light is used for the first pressure-sensitive adhesive layer, the average transmittance T of the first pressure-sensitive adhesive layer at a wavelength of 330 to 400nm is UV Will be greater than the average transmittance T of the wavelength of 400-700 nm VIS . Average transmittance T of the first adhesive layer at a wavelength of 400 to 700nm VIS For example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less. The first adhesive layer has an average transmittance T of 330 to 400nm UV Preferably 5% or more, and may be 10% or more, 15% or more, 20% or more, or 25% or more. T is a unit of UV And T VIS Difference of difference T UV -T VIS May be 3% or more, 5% or more, 8% or more, or 10% or more.
In the first aspect, the visible light transmittance T to the second pressure-sensitive adhesive layer 2 The content is not particularly limited, and may be, for example, 85 to 100%, 88% or more, 90% or more, or 92% or more. As described above, the light-emitting efficiency is improved by covering the upper portion (image display side) of the light-emitting element of the self-luminous display device with the second adhesive layer having high permeability.
In the first embodiment, the shear storage modulus G'25 ℃ at a temperature of 25 ℃ of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is, for example, about 10 to 1000kPa, and may be 30kPa or more, 50kPa or more, 70kPa or more, or 100kPa or more, and may be 700kPa or less, 500kPa or less, 300kPa or less, or 200kPa or less. The shear storage modulus G'85 ℃ at a temperature of 85 ℃ in the pressure-sensitive adhesive layer is, for example, about 3 to 300kPa, and may be 5kPa or more, 7kPa or more, or 10kPa or more, and may be 200kPa or less, 150kPa or less, or 100kPa or less. When the shear storage modulus of the pressure-sensitive adhesive layer is in the above range, both appropriate flexibility and adhesiveness can be achieved. The shear storage modulus is a measured value based on a dynamic viscoelasticity measurement at a frequency of 1 Hz.
[ second mode ]
An optical laminate having the adhesive layer of the second embodiment may be prepared as follows: the photocurable adhesive composition of the second embodiment is applied to a release film, and the solvent is dried and removed as necessary to form a second adhesive layer, which is then attached to the surface 3b of the substrate 3. Next, the photocurable adhesive composition of the second embodiment is applied to a release film, and the solvent is dried and removed as necessary to form a first adhesive layer, which is then bonded to the second adhesive layer laminated on the surface 3b of the substrate 3.
In addition, an optical laminate having the adhesive layer of the second embodiment may also be prepared as follows: the photocurable adhesive composition of the second embodiment is applied to the surface 3b of the substrate 3, and the solvent is dried and removed as necessary, thereby forming a second adhesive layer. Next, the photocurable adhesive composition of the second embodiment is applied to a release film, and the solvent is dried and removed as necessary to form a first adhesive layer, which is then bonded to the second adhesive layer laminated on the surface 3b of the substrate 3.
When the photocurable adhesive composition contains a solvent, the solvent is preferably dried after the adhesive composition is applied. As the drying method, an appropriate method can be adopted according to the purpose. The heating and drying temperature is preferably 40 to 200 ℃, more preferably 50 to 180 ℃, and particularly preferably 70 to 170 ℃. The drying time may be appropriately set to an appropriate time. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.
After the application of the photocurable adhesive composition, the polymer is heated as necessary to introduce a crosslinked structure. The heating temperature and the heating time may be appropriately set depending on the kind of the crosslinking agent to be used, and are usually in the range of 20 to 160 ℃ for about 1 minute to 7 days. The heating for drying the solvent may double as the heating for crosslinking. The introduction of the crosslinked structure does not necessarily require heating.
The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the second embodiment preferably have the same thickness (thickness, total thickness, and ratio of thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer), light transmittance, and shear storage modulus as those of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first embodiment, respectively. Since the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the second embodiment are not photocured, the photopolymerizable compound is contained in an unreacted state. That is, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the second embodiment are photocurable pressure-sensitive adhesive layers containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and, if necessary, a colorant.
The optical laminate having the photocurable first pressure-sensitive adhesive layer and/or the photocurable second pressure-sensitive adhesive layer according to the second embodiment can be photocured by irradiating ultraviolet rays after being bonded to a display panel described later. The adhesive strength between the optical laminate and the display panel can be changed by photocuring. For example, the adhesive layer before photocuring is highly flexible, and therefore can fill irregularities and level differences formed by the light-emitting elements arranged on the display panel, and can improve adhesion to the display panel and adhesion reliability after photocuring.
As the active ray for photo-curing the adhesive layer, ultraviolet rays can be used. In the case of using an ultraviolet-transmitting colorant as in the adhesive layer of the first embodiment, since the ultraviolet transmittance is higher than that of visible light, the inhibition of curing during photocuring can be suppressed even when the thickness of the adhesive layer is large.
An optical laminate having the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the first and second embodiments, which contain the ultraviolet-permeable colorant, has light absorption in visible light. The optical layered body according to the first and second embodiments preferably has a maximum transmittance in a range of 350nm to 450 nm.
The visible light transmittance of the optical laminate of the first and second embodiments is, for example, 80% or less, and may be 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.
[ third mode ]
An optical laminate having the adhesive layer of the third embodiment may be prepared as follows: the solvent-based adhesive composition of the third embodiment is applied to a release film, and the solvent is dried and removed as necessary to form a second adhesive layer, which is then attached to the surface 3b of the base 3. Next, the solvent-based adhesive composition of the third embodiment is applied to a release film, and the solvent is dried and removed as necessary to form a first adhesive layer, which is then bonded to the second adhesive layer laminated on the surface 3b of the base material 3.
Further, an optical laminate having the adhesive layer of the third embodiment may also be prepared as follows: the solvent-based adhesive composition of the third embodiment is applied to the surface 3b of the base material 3, and the solvent is dried and removed as necessary, thereby forming a second adhesive layer. Next, the solvent-based adhesive composition of the third embodiment is applied to a release film, and the solvent is dried and removed as necessary to form a first adhesive layer, which is then bonded to the second adhesive layer laminated on the surface 3b of the base material 3.
After the solvent-based adhesive composition is applied, the solvent is dried. As the drying method, an appropriate method can be adopted according to the purpose. The heating and drying temperature is preferably 40 to 200 ℃, more preferably 50 to 180 ℃, and particularly preferably 70 to 170 ℃. The drying time may be appropriately selected. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.
After the application of the photocurable adhesive composition, heating may be performed as necessary. The heating temperature and the heating time may be appropriately set depending on the kind of the crosslinking agent to be used, and are usually in the range of 20 to 160 ℃ for about 1 minute to 7 days.
The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the third aspect preferably have the same thickness (thickness, total thickness, and ratio of thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer), light transmittance, and shear storage modulus as the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first aspect, respectively.
The storage modulus (G' 25) at 25 ℃ of the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer (particularly the first pressure-sensitive adhesive layer) when the solvent-based adhesive composition contains the (meth) acrylic block copolymer a is not particularly limited, but is preferably 1MPa or more, more preferably 1.5MPa or more, more preferably 2MPa or more, more preferably 2.5MPa or more, and more preferably 3MPa or more, from the viewpoint of improving processability at room temperature, and is preferably 50MPa or less, more preferably 45MPa or less, more preferably 40MPa or less, more preferably 35MPa or less, and more preferably 30MPa or less from the viewpoint of improving adhesion reliability at room temperature.
The storage modulus (G' 50) at 50 ℃ of the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer (particularly the first pressure-sensitive adhesive layer) when the solvent-based pressure-sensitive adhesive composition contains the (meth) acrylic block copolymer a is not particularly limited, but is preferably 0.5MPa or less, more preferably 0.45MPa or less, more preferably 0.4MPa or less, more preferably 0.35MPa or less, more preferably 0.3MPa or less, from the viewpoint of improving the level difference absorptivity in the region exceeding 50 ℃, and is preferably 0.0001MPa or more, more preferably 0.0005MPa or more, more preferably 0.001MPa or more, more preferably 0.005MPa or more, more preferably 0.01MPa or more from the viewpoint of improving the workability in the region exceeding 50 ℃.
The ratio (G '25/G' 50) of the storage modulus at 25 ℃ to the storage modulus at 50 ℃ of the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer (particularly, the first pressure-sensitive adhesive layer) when the solvent-based pressure-sensitive adhesive composition contains the (meth) acrylic block copolymer a is not particularly limited, but is preferably 3 or more, more preferably 5 or more, more preferably 10 or more, further preferably 15 or more, and particularly preferably 20 or more from the viewpoint of improving processability at room temperature and improving the level difference absorptivity in the region exceeding 50 ℃, and is preferably 100 or less, more preferably 95 or less, more preferably 90 or less, further preferably 85 or less, and particularly preferably 80 or less from the viewpoint of adhesion reliability, handling property, and the like.
The storage modulus at 25 ℃ (G '25) and the storage modulus at 50 ℃ (G' 25) and the ratio thereof (G '25/G' 50) are measured by dynamic viscoelasticity measurement.
The optical laminate having the first adhesive layer and/or the second adhesive layer of the third embodiment containing a colorant has light absorption for visible light.
The visible light transmittance of the optical laminate of the third embodiment is, for example, 80% or less, and may be 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.
The optical laminate according to the present embodiment (first to third embodiments) may be provided with a release film on the pressure-sensitive adhesive layer until the time of use. In the optical laminate according to the present embodiment (first to third embodiments), a surface protective film may be laminated on the surface 3a of the substrate 3. The surface protective film is suitable in the following respects: the optical laminate and the optical product including the same are prevented from being damaged or contaminated during production, transportation, and shipment of the optical laminate.
The optical laminate of the present embodiment (first to third embodiments) may have other layers on the surface or between any layers, for example, a substrate other than the substrate 3, an adhesive layer other than the first adhesive layer 1 and the second adhesive layer 2, an intermediate layer, and a primer layer, in addition to the first adhesive layer 1, the second adhesive layer 2, the substrate 3, the release film, and the surface protective film, within a range not impairing the effects of the present invention.
< self-luminous display device >
A self-light-emitting display device of a second aspect of the present invention is: a display device in which a large number of minute light-emitting elements are arranged on a wiring board and the light-emitting elements are selectively caused to emit light by a light-emission control means connected thereto, whereby visual information such as characters, images, and videos can be directly displayed on a display screen by turning on and off the light-emitting elements. Examples of the self-luminous display device include: mini/Micro LED display device, organic EL (electroluminescence) display device. The optical laminate of the third aspect of the present invention is particularly suitable for use in the production of Mini/Micro LED display devices.
Fig. 4 to 6 are schematic views (cross-sectional views) showing one embodiment of a self-light emitting display device (Mini/Micro LED display device) of a second aspect of the present invention. The Mini/Micro LED display device 20 of the present embodiment includes a display panel in which a plurality of LED chips 7 are arranged on one surface of a substrate 5, and an optical laminate 10. The surface of the display panel on which the LED chips 7 are arranged is laminated with the first adhesive layer 1 of the optical laminate 10. In the Mini/Micro LED display device 21, the surface 3a of the base material 3 on which the second pressure-sensitive adhesive layer 2 is not laminated is subjected to an antireflection treatment and/or an antiglare treatment 4. In the Mini/Micro LED display device 22, the surface 3a of the base material 3 on which the second pressure-sensitive adhesive layer 2 is not laminated is provided with an antiglare layer 4a as an antiglare treatment.
In the present embodiment, a metal wiring layer 6 for transmitting a light emission control signal to each LED chip 7 is laminated on a substrate 5 of the display panel. The LED chips 7 emitting light of red (R), green (G), and blue (B) colors are alternately arranged on the substrate 5 of the display panel via the metal wiring layer 6. The metal wiring layer 6 is formed of a metal such as copper, and reflects light emitted from each LED chip 7, thereby reducing visibility of an image. Further, the light emitted from each LED chip 7 of each color of RGB is mixed, and the contrast is lowered.
In the Mini/Micro LED display device of the present embodiment, the first adhesive layer 1 encapsulates the metal wiring layer 6 and the space between the LED chips 7 arranged on the display panel. By making the visible light transmittance of the first adhesive layer 1 lower than that of the second adhesive layer 2, sufficient light-shielding properties in the visible light region are provided. Since the first pressure-sensitive adhesive layer 1 having higher light-shielding properties (having lower permeability) encapsulates the LED chips 7 without a gap therebetween, color mixing between the LED chips 7 can be prevented, and contrast can be improved. Further, since the first adhesive layer 1 having higher light-shielding property (lower permeability) encapsulates the surface of the metal wiring layer 6 as well, reflection by the metal wiring layer 6 can be prevented.
In the present embodiment, the second adhesive layer 2 encapsulates the upper portion (on the display image side) of each LED chip 7 arranged on the display panel. By making the visible light transmittance of the second adhesive layer 2 higher than that of the first adhesive layer 1, sufficient transmittance in the visible light region is obtained. Since the second adhesive layer 2 having higher transmittance encapsulates the upper portion (display image side) of each LED chip 7, absorption of visible light emitted from each LED chip 7 can be suppressed to be low, and light emission efficiency can be improved, whereby an image can be made brighter. In addition, since the output power does not need to be increased to increase the light emission luminance, power consumption can be suppressed to be low.
As described above, the optical laminate of the present embodiment includes the first pressure-sensitive adhesive layer having higher light-shielding properties (having lower permeability), and therefore, even when a metal adherend is laminated on the first pressure-sensitive adhesive layer, reflection and gloss on the metal surface can be prevented. The reflectance in the visible light region of the 5 ° regular reflection on the base material surface 3a when the metal adherend is laminated on the first pressure-sensitive adhesive layer of the optical laminate of the present embodiment is preferably 50% or less, more preferably 30% or less, further preferably 15% or less, and particularly preferably 10% or less. The glossiness (based on JIS Z8741-1997) of the substrate surface 3a when a metal adherend is laminated on the first pressure-sensitive adhesive layer of the optical laminate of the present embodiment is preferably 100% or less, more preferably 80% or less, further preferably 60% or less, and particularly preferably 50% or less.
As the metal adherend, copper, aluminum, stainless steel, or the like can be used.
In the Mini/Micro LED display device of the present embodiment, when the surface 3a of the base material 3 is subjected to the antireflection treatment and/or the antiglare treatment 4, deterioration in visibility due to reflection of external light, reflection of an image, or the like on the surface 3a of the base material is prevented, or the appearance such as glossiness is adjusted. In the Mini/Micro LED display device 22 of the present embodiment, an antiglare layer 4a is formed on the surface 3a of the base material 3. The average inclination angle θ a (°) of the antiglare layer 4a of the Mini/Micro LED display device 22 of the present embodiment is the same as described above.
The self-luminous display device of the present embodiment may include an optical member other than the display panel and the optical laminate. The optical member is not particularly limited, and examples thereof include: polarizing plates, retardation plates, antireflection films, viewing angle adjusting films, optical compensation films, and the like. The optical member includes a member (a decorative film, a surface protection plate, and the like) which plays a role of decoration and protection while maintaining visibility of the display device and the input device.
The Mini/Micro LED display device of the present embodiment can be manufactured by bonding a display panel having a plurality of LED chips arranged on one surface of a substrate to the first adhesive layer of the optical laminate of the first aspect of the present invention.
Specifically, the optical laminate including the display panel and the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the first embodiment can be bonded by laminating under heat and/or pressure. In the case of bonding an optical laminate including a display panel and the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the second aspect, the optical laminate may be laminated under heat and/or pressure and then photocured. The photocuring can be performed in the same manner as the photocuring for forming the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the first embodiment.
When the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer is formed from a solvent-based pressure-sensitive adhesive composition containing a (meth) acrylic block copolymer a, the bonding is preferably performed by heating and pressing at 50 ℃ or higher. By heating and pressurizing at 50 ℃ or higher, the adhesive layer has high fluidity, and can sufficiently follow the height difference of the LED chips arranged on the substrate, and can be closely adhered without a gap. The heating is carried out at 50 ℃ or higher, preferably 60 ℃ or higher, and more preferably 70 ℃ or higher. The pressurization is not particularly limited, and is performed, for example, at 1.5atm or more, preferably at 2atm or more, and more preferably at 3atm or more. The heating and pressurizing can be performed using, for example, an autoclave. After the Mini/Micro LED display device thus manufactured was returned to room temperature (25 ℃), the storage modulus of the adhesive layer was increased, and the workability and adhesion reliability were improved.
Examples
The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Various properties in the following production examples were evaluated or measured by the following methods.
(measurement of surface shape)
A glass plate (thickness: 1.3 mm) manufactured by Sonlang glass industries, inc. was bonded to the surface of an antiglare film, on which an antiglare layer was not formed, with an adhesive, and the surface shape of the antiglare layer was measured with a high-precision fine shape measuring instrument (trade name; surfcorder ET4000, manufactured by Showa Kaisha) at a cutoff value of 0.8mm to determine an average tilt angle thetaa. The high-precision fine shape measuring device automatically calculates the average inclination angle θ a. The average tilt angle θ a is based on JIS B0601 (1994 version).
(haze)
The haze value was measured by a method prescribed in JIS K7136, by setting a haze meter (product name "HN-150" manufactured by color technology research on village, ltd.) into which light is incident from the antiglare layer of the antiglare film.
(visible light transmittance of adhesive sheet)
The peeling film on one surface is peeled from the adhesive sheet, and the alkali-free glass is bonded to the exposed surface. Then, the other side of the release film was peeled from the adhesive sheet to obtain a sample in which the adhesive sheet was bonded to an alkali-free glass plate. Using this sample, the transmission spectrum of the sample for evaluation was measured by a visible-ultraviolet spectrophotometer (manufactured by Hitachi High-Technologies Corporation, trade name "U-4100"). The transmittance of the adhesive sheet was determined by taking the alkali-free glass (simple substance) as a base line and the ratio of the transmittance (transmitted light amount) of the sample for evaluation to the transmittance (transmitted light amount) of the alkali-free glass. From the transmission spectrum of the adhesive sheet, the transmittance T at a wavelength of 550nm was calculated VIS 。
(visible light transmittance of anti-glare film)
The antiglare film was set to a spectrophotometer U4100 (manufactured by High-Technologies Corporation) so that light was incident from the antiglare layer side, and the transmittance (%) in the visible light region was measured. The transmittance is a Y value measured in a 2-degree field of view (C light source) according to JIS Z8701 and corrected for visibility.
Production example 1
(preparation of anti-glare film)
100 parts by weight of an ultraviolet-curable urethane acrylate resin (trade name "UNIDIC 17-806" manufactured by DIC corporation, solid content 80%) was prepared as a resin included in the antiglare layer. To 100 parts by weight of the resin solid content of the resin, 14 parts by weight of styrene crosslinked particles (trade name "MX-350H", weight average particle diameter: 3.5 μm, refractive index: 1.59, manufactured by seikagaku corporation) as light-diffusing fine particles, 2.5 parts by weight of synthetic montmorillonite (kunmine INDUSTRIES co., ltd., trade name "SURECTON SAN") as a thixotropy-imparting agent, 5 parts by weight of a photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF corporation), and 0.5 part by weight of a leveling agent (trade name "MEGAFAC-556", solid content 100%) were mixed. This mixture was diluted with a toluene/ethyl acetate mixed solvent (weight ratio 90/10) to a solid content concentration of 30% by weight, to prepare a light diffusing element-forming material (coating liquid).
An anti-glare layer-forming material (coating liquid) was applied to one surface of a triacetyl cellulose (TAC) film (product name "TG60UL" manufactured by Fuji photo film Co., ltd., thickness: 60 μm) that can function as a protective layer by a bar coater to form a coating film. Then, the transparent TAC film substrate on which the coating film is formed is conveyed to a drying step. In the drying step, the coating film is dried by heating at 110 ℃ for 1 minute. Then, the accumulated light amount was irradiated with 300mJ/cm by a high-pressure mercury lamp 2 The coating film was cured to form a light diffusing element with a thickness of 5.0 μm on one side of the TAC film, thereby obtaining an antiglare film 1.The haze value of the antiglare film 1 was 42%. The antiglare layer of the antiglare film 1 had θ a (°) of 1.22. The visible light transmittance of the antiglare film 1 was 90%.
Production example 2
(preparation of anti-glare film)
A light diffusing element was formed on one surface of the TAC film in the same manner as in production example 1 except that 14 parts by weight of amorphous silica (product name "SYLOPHOBIC 100" manufactured by Fuji simple chemical ltd., having a weight average particle diameter of 2.6 μm) was added as the light diffusing fine particles so that the thickness after curing was 7.0 μm, thereby obtaining an antiglare film 2. The haze value of the antiglare film 2 was 11%. The antiglare layer of the antiglare film 2 had θ a (°) of 1.43. The visible light transmittance of the antiglare film 2 was 91%.
Production example 3
(preparation of antiglare film)
100 parts by weight of an ultraviolet-curable urethane acrylate resin (product name "UNIDIC 17-806" manufactured by DIC corporation, solid content 80%) was prepared as a resin contained in the antiglare layer-forming material. With respect to 100 parts by weight of the resin solid content of the resin, as antiglare layer-forming particles, 7 parts by weight of amorphous silica (trade name "SYLOPHOBIC 702" manufactured by Fuji Silysia chemical ltd.), 6.5 parts by weight of amorphous silica (trade name "SYLOPHOBIC 100" manufactured by Fuji Silysia chemical ltd.), 5 parts by weight of a photopolymerization initiator (trade name "OMNIRAD184" manufactured by BASF corporation) and 0.5 part by weight of a leveling agent (trade name "MEGAFAC F-556" manufactured by DIC corporation) were mixed. The mixture was diluted with toluene to a solid content concentration of 30% to prepare an antiglare layer-forming material (coating liquid).
As the light-transmitting substrate, a transparent plastic film substrate (TAC film, manufactured by Fuji film Co., ltd., trade name "TD80UL", thickness: 80 μm) was prepared. The antiglare layer-forming material (coating liquid) was applied to one surface of the transparent plastic film substrate by a bar coater to form a coating film. Then, the transparent plastic film substrate on which the coating film is formed is conveyed to a drying step. In the dry stateIn the drying step, the coating film is dried by heating at 110 ℃ for 1 minute. Then, the accumulated light amount was irradiated with 300mJ/cm by a high-pressure mercury lamp 2 The coating film was cured with ultraviolet rays to form an antiglare layer having a thickness of 5.0 μm, thereby obtaining an antiglare film 3. The antiglare layer of the antiglare film 3 had θ a (°) of 3.5. The antiglare film 3 had a visible light transmittance of 91%.
Production example 4
(preparation of antiglare film)
An antiglare film 4 was obtained in the same manner as in production example 3, except that 6.5 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical ltd., trade name "sylophbic 702"), 6.5 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical ltd., trade name "sylophbic 200"), and 2.5 parts by weight of a tackifier (Co-op Chemical Co., manufactured by ltd., trade name "lucent SAN") were added to the particles forming the antiglare layer, and the thickness after curing treatment was set to 8.0 μm. The antiglare layer of the antiglare film 4 had θ a (°) of 2.3. The antiglare film 4 had a visible light transmittance of 91%.
Production example 5
(preparation of prepolymer)
67 parts by weight of Butyl Acrylate (BA), 14 parts by weight of cyclohexyl acrylate (CHA, product name "Viscoat #155" manufactured by Osaka organic chemical industries, ltd.), 19 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.09 part by weight of a photopolymerization initiator (product name "IRGACURE 184" manufactured by BASF) and 0.09 part by weight of a photopolymerization initiator (product name "IRGACURE 651" manufactured by BASF) were put into a separable flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube, and then nitrogen gas was introduced thereinto and replaced with nitrogen gas for about 1 hour while stirring. Then, at 5mW/cm 2 UVA is irradiated to carry out polymerization, and the reaction rate is adjusted to 5-15%, so that an acrylic prepolymer solution is obtained.
Production example 6
(preparation of Polymer RAFT solution A1)
50 parts by weight of cyclohexyl acrylate (CHA), 50 parts by weight of 3, 5-trimethylcyclohexyl acrylate (TMCHA), 0.5 part by weight of dibenzyl trithiocarbonate (DBTC) as a RAFT agent, and 100 parts by weight of ethyl acetate as a polymerization solvent were charged into a reaction vessel equipped with a condenser tube, a nitrogen inlet tube, a thermometer, and a stirrer, and 0.2 part by weight of 2,2' -Azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was charged and solution polymerization was carried out in a nitrogen atmosphere, thereby obtaining a polymer RAFT solution A1 having Mw of 18 ten thousand.
(preparation of acrylic triblock copolymer-containing adhesive solution B1)
To a reaction vessel equipped with a condenser tube, a nitrogen inlet tube, a thermometer and a stirrer, 97 parts by weight of 2-ethylhexyl acrylate (2 EHA), 3 parts by weight of 4-hydroxybutyl acrylate (4 HBA), 100 parts by weight of the polymer RAFT solution A1 obtained above and 100 parts by weight of ethyl acetate as a polymerization solvent were fed as monomer components, 0.2 part by weight of 2,2' -Azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was fed, and solution polymerization was performed in a nitrogen atmosphere, thereby obtaining a binder solution B1 containing an ABA type acrylic triblock copolymer having Mw of 40 ten thousand and Mw/Mn of 4.3.
In the calculated glass transition temperature (Tg) based on the formula FOX, the Tg of segment A of the ABA type acrylic triblock copolymer was 32 ℃ and the Tg of segment B was-70 ℃.
The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) of the above product were measured in terms of standard polystyrene by gel permeation chromatography (GCP method) under the following measurement conditions.
The measurement device: HLC-8320GPC (manufactured by Tosoh corporation)
Column chromatography: TSKgelGMH-H (S) (manufactured by Tosoh corporation)
Mobile phase solvent: tetrahydrofuran (THF)
Flow rate: 1.0cm 3 /min
Column temperature: 40 deg.C
Production example 7
(preparation of Black adhesive composition)
To the acrylic prepolymer solution obtained in production example 5 (the total amount of the prepolymer was set to 100 parts by weight), 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.02 part by weight of dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by NONSUMU.S. CORPORATION), 0.35 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and 0.3 part by weight of a photopolymerization initiator (trade name "IRGACURE 651", manufactured by BASF) 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 (product name "IRGACURE 651", manufactured by BASF) and 4 parts by weight of a Black pigment dispersion (product name "TOKUSHIKI 9050Black", manufactured by ltd., ltd.) were added to prepare a photopolymerizable Black adhesive composition solution.
Production example 8
(preparation of Black adhesive composition)
To the acrylic triblock copolymer-containing adhesive solution B1 obtained in production example 6, 2 parts by weight of a BLACK dye (obtained organic CHEMICAL additives co., ltd., product "VALIFAST BLACK 3810") was added, based on 100 parts by weight of the total amount of the monomers used in production example 6, to prepare a BLACK solvent-based adhesive composition solution.
Production example 9
(preparation of adhesive composition)
To the acrylic prepolymer solution obtained in production example 5 (the total amount of the prepolymer was set to 100 parts by weight), 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.12 parts by weight of dipentaerythritol hexaacrylate (product name "KAYARAD DPHA", manufactured by NONSHOUKI chemical Co., ltd.) as a polyfunctional monomer and 0.35 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent were added to prepare a photopolymerizable adhesive composition solution.
Production example 10
(preparation of adhesive sheet)
A release film R1 (Mitsubishi resin type) having a thickness of 38 μm and having a release surface on one side of the polyester filmTrade name "MRF #38", manufactured by mitsubishi corporation), the black pressure-sensitive adhesive composition solution prepared in production example 7 was applied so that the thickness after curing was 50 μm, and a release film R2 (MRE #38, manufactured by mitsubishi resin corporation) having a release surface on one surface of the polyester film was covered to block air. From one side of the laminate, a black light lamp (product name: FL15BL, manufactured by Toshiba Co., ltd.) was used to irradiate at an illuminance of 5mW/cm 2 1300mJ/cm of accumulated light amount 2 The condition (2) is ultraviolet ray irradiation. Thus, a pressure-sensitive adhesive sheet 1 having a thickness of 50 μm, in which the photo-crosslinkable pressure-sensitive adhesive as a cured product of the black pressure-sensitive adhesive composition was sandwiched between the release films R1 and R2, was obtained in the form of a substrate-free pressure-sensitive adhesive sheet.
The value of the illuminance of the black light lamp was measured by an industrial UV detector (manufactured by TOPCON CORPORATION, trade name: UVR-T1, and light receiver model number UD-T36) having a peak sensitivity wavelength of about 350 nm.
The visible light transmittance of the adhesive sheet 1 was 40%.
Production example 11
(preparation of adhesive sheet)
A 100 μm thick psa sheet 2 was obtained in the form of a substrate-free psa sheet, in which a photo-crosslinkable psa, which was a cured product of a black psa composition, was sandwiched between release films R1, R2, in the same manner as in production example 10, except that the cured psa sheet was coated to a thickness of 100 μm.
The visible light transmittance of the adhesive sheet 2 was 16%.
Production example 12
(preparation of adhesive sheet)
A 150 μm thick psa sheet 3 was obtained in the form of a substrate-free psa sheet, in which a photo-crosslinkable psa, which is a cured product of a black psa composition, was sandwiched between release films R1, R2, in the same manner as in production example 10, except that the cured psa sheet was coated to a thickness of 150 μm.
The visible light transmittance of the adhesive sheet 3 was 3%.
Production example 13
(preparation of adhesive sheet)
A75 μm thick polyethylene terephthalate (PET) film (DIAFOIL MRF75, manufactured by Mitsubishi chemical corporation) having a silicone-based release layer formed on the surface thereof was used as a substrate, and the black solvent-based adhesive composition solution prepared in production example 8 was applied to the substrate and dried at 130 ℃ for 3 minutes to form a 50 μm thick adhesive layer. To this pressure-sensitive adhesive layer, a 75 μm thick PET film (DIAFOIL MRE75, manufactured by mitsubishi chemical) having one side subjected to silicone release treatment was bonded, and a pressure-sensitive adhesive sheet 4 having a release film attached to both sides thereof was obtained in the form of a substrate-free pressure-sensitive adhesive sheet.
The visible light transmittance of the adhesive sheet 4 is less than 1%.
Production example 14
(preparation of adhesive sheet)
A 75 μm thick psa sheet 5 was obtained in the form of a baseless psa sheet with the psa layer of the black solvent-based psa composition sandwiched between release films, in the same manner as in production example 13, except that the black solvent-based psa composition solution prepared in production example 8 was applied to a dried thickness of 75 μm.
The visible light transmittance of the adhesive sheet 5 is less than 1%.
Production example 15
(preparation of adhesive sheet)
A 100 μm thick adhesive sheet 6 in which the adhesive layer of the black solvent-based adhesive composition was sandwiched between release films was obtained in the form of a substrate-free adhesive sheet in the same manner as in production example 13, except that the black solvent-based adhesive composition solution prepared in production example 8 was applied so that the thickness after drying was 100 μm.
The visible light transmittance of the adhesive sheet 6 is less than 1%.
Production example 16
(preparation of adhesive sheet)
A pressure-sensitive adhesive sheet 7 having a thickness of 100 μm sandwiched between release films R1 and R2, which was a cured product of the pressure-sensitive adhesive composition, was obtained in the form of a substrate-less pressure-sensitive adhesive sheet in the same manner as in production example 10, except that the pressure-sensitive adhesive composition solution prepared in production example 9 was applied so that the thickness after curing was 100 μm.
The visible light transmittance of the adhesive sheet 7 was 90%.
Production example 17
(preparation of adhesive sheet)
A pressure-sensitive adhesive sheet 8 having a thickness of 200 μm sandwiched between release films R1 and R2 was obtained as a substrate-free pressure-sensitive adhesive sheet in the same manner as in production example 10, except that the pressure-sensitive adhesive composition solution prepared in production example 9 was applied so that the thickness after curing was 200 μm.
The visible light transmittance of the adhesive sheet 8 was 90%.
Example 1
(preparation of optical laminate)
The release film on one side peeled from the pressure-sensitive adhesive sheet 8 obtained in production example 17 cut to 20mm × 20mm was adhered to the center of a 45mm × 50mm glass plate (visible light transmittance: 93%), and then the release film on the other side was peeled off to expose the pressure-sensitive adhesive surface. The pressure-sensitive adhesive sheet 1 obtained in production example 10 was cut into 20mm × 20mm, and the pressure-sensitive adhesive surface exposed by peeling the release film on the side from which the pressure-sensitive adhesive sheet 1 was peeled was bonded to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet 8, thereby obtaining an optical laminate 1 composed of a glass plate/pressure-sensitive adhesive sheet 8/pressure-sensitive adhesive sheet 1/release film.
Examples 2 to 6
(preparation of optical laminate)
Optical laminates 2 to 6 each composed of a glass plate/adhesive sheet 8/adhesive sheets 2 to 6/release film were obtained in the same manner as in example 1 except that adhesive sheets 2 to 6 were used instead of adhesive sheet 1.
Comparative example 1
(preparation of optical laminate)
An optical laminate 7 composed of a glass plate/adhesive sheet 8/adhesive sheet 7/release film was obtained in the same manner as in example 1, except that the adhesive sheet 7 was used instead of the adhesive sheet 1.
(evaluation)
The optical layered bodies obtained in the above examples and comparative examples were subjected to the following evaluations. The evaluation method is shown below.
(1) Evaluation of following Properties for level differences
(preparation of uneven adherend)
A laminate of a TAC film (thickness 60 μm) and an adhesive (thickness 20 μm) was bonded to a 45mm X50 mm glass plate, and then CO was used 2 The laser (wavelength 10.6 μm, laser diameter good μm) was linearly etched in a range of 10mm × 10mm at the center at a pitch of 150 μm in the longitudinal direction and at a pitch of 225 μm in the width direction, thereby obtaining an adherend a in which a TAC film and a pressure-sensitive adhesive layer were processed into a lattice-shaped irregular shape.
This adherend a simulates an LED panel in which a plurality of LED chips are arranged on a substrate.
(vacuum bonding)
Samples 1 to 7 for evaluation each composed of a glass plate/pressure-sensitive adhesive sheet 8/pressure-sensitive adhesive sheets 1 to 7/adherend a were obtained by bonding the pressure-sensitive adhesive surfaces exposed by peeling the release films of the optical laminates 1 to 7 prepared in examples 1 to 6 and comparative example 1 to the processing surface of the adherend a with a vacuum bonding apparatus (manufactured by Climb Products, SE340 aaH) with such accuracy that the pressure-sensitive adhesive sheets can completely cover the processing range of the adherend a.
(evaluation of following-up to height)
In the evaluation samples 1 to 7, the difference in level following property was evaluated by taking an image of the area of the white formic acid portion with a fixed point camera, taking advantage of the property that the processed portion of the adherend a appeared transparent and the unsuccessfully followed portion appeared white when the adhesive sheet successfully followed the pattern portion of the uneven shape.
Height difference following Property (%) = area of white portion at evaluation of 100- { []/[ area of white part before bonding =1cm 2 ]×100}
The level difference following property was measured immediately after the bonding and after the autoclave (15 minutes, 30 minutes, and 60 minutes under the conditions of 50 ℃ and 0.5 MPa). The results are shown in Table 1.
[ Table 1]
(Table 1)
Figure BDA0003872505190000691
(2) Transmittance of visible light
The optical layered bodies obtained in the above examples and comparative examples were set in a spectrophotometer U4100 (manufactured by High-Technologies Corporation) so that light entered from the glass plate side, and the transmittance (%) in the visible light region was measured. The transmittance is a Y value measured in a 2-degree field of view (C light source) according to JIS Z8701 and corrected for visibility. The results are shown in Table 2.
(3) Reflectivity of light
A plate was prepared by laminating aluminum foil on a black acrylic plate. The pressure-sensitive adhesive surface exposed by peeling the release film of the optical laminate obtained in the above examples and comparative examples was laminated on the aluminum foil side of the plate to prepare a sample. The obtained sample was set in a spectrophotometer U4100 (manufactured by Hitachi High-Technologies Corporation) with the anti-glare film/TAC film on the light source side, and the reflectance (%) in the visible light region of regular reflection at 5 ° was measured.
[ Table 2]
(Table 2)
Transmittance (550 nm) Reflectivity (550 nm)
Example 1 40％ 18％
Example 2 16％ 7％
Example 3 3％ 5％
Example 4 <1％ 4％
Example 5 <1％ 4％
Example 6 <1％ 4％
Comparative example 1 90％ 73％
Example 7
(preparation of optical laminate)
The pressure-sensitive adhesive surface exposed by peeling off the release film on one side from the pressure-sensitive adhesive sheet 8 obtained in production example 17 cut to 20mm × 20mm was adhered to the center portion of the surface of the antiglare film 1 obtained in production example 1 cut to 45mm × 50mm where the antiglare layer was not formed, and then the release film on the other side was peeled off to expose the pressure-sensitive adhesive surface. An optical laminate 8 comprising an antiglare film 1/pressure-sensitive adhesive sheet 8/pressure-sensitive adhesive sheet 1/release film was obtained by bonding the pressure-sensitive adhesive surface exposed by peeling the release film from the pressure-sensitive adhesive sheet 1 obtained in production example 10 cut into 20mm × 20mm to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet 8.
Examples 8 to 10
(preparation of optical laminate)
Optical laminates 9 to 11 each composed of an antiglare film 2 to 4, an adhesive sheet 8, an adhesive sheet 1 and a release film were obtained in the same manner as in example 7, except that the antiglare films 2 to 4 obtained in production examples 2 to 4 were used instead of the antiglare film 1.
Various modifications of the present invention will be described below.
[ additional note 1] an optical laminate having a laminate structure in which a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer, and a substrate are laminated in this order,
the visible light transmittance T of the first adhesive layer 1 And a visible light transmittance T of the second adhesive layer 2 Satisfy T 1 <T 2 。
[ attached note 2)]The optical laminate according to supplementary note 1, wherein the first pressure-sensitive adhesive layer has a visible light transmittance T 1 And the visible light transmittance T of the base material 3 Satisfy T 1 <T 3 。
[ appendix 3]]The optical laminate according to supplementary note 1 or 2, wherein the first pressure-sensitive adhesive layer has a visible light transmittance T 1 Is 80% or less.
[ attached note 4]The optical laminate according to any one of supplementary notes 1 to 3, wherein the second pressure-sensitive adhesive layer has a visible light transmittance T 2 Is 85 to 100 percent.
[ additional 5] the optical laminate according to any one of additional 1 to additional 4, wherein the first adhesive layer and the second adhesive layer are adhesive layers formed from an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition.
[ appendix 6] the optical laminate according to appendix 5, wherein the adhesive composition forming the first adhesive layer contains a colorant.
[ appendix 7] the optical laminate according to appendix 5 or 6, wherein the pressure-sensitive adhesive composition contains an acrylic polymer.
[ appendix 8] the optical laminate according to appendix 7, wherein the acrylic polymer comprises a (meth) acrylic block copolymer.
[ additional character 9] the optical laminate according to additional character 8, wherein the adhesive composition forming the first adhesive layer is a solvent-based adhesive composition containing a (meth) acrylic block copolymer.
[ additional note 10] the optical laminate according to any one of additional notes 1 to 9, wherein the thickness of the first pressure-sensitive adhesive layer is 10 to 300 μm.
[ appendix 11] the optical laminate according to any one of appendix 1 to 10, wherein the second pressure-sensitive adhesive layer has a thickness of 1 to 500 μm.
[ additional note 12] the optical laminate according to any one of additional notes 1 to 11, wherein a ratio of the thickness of the second pressure-sensitive adhesive layer to the thickness of the first pressure-sensitive adhesive layer (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is 1.0 to 5.0.
[ additional ] 13] the optical laminate according to any one of additional 1 to 12, wherein a surface of the base material on which the second pressure-sensitive adhesive layer is not laminated is subjected to an antireflection treatment and/or an antiglare treatment.
[ additional character 14] the optical laminate according to additional character 13, wherein the anti-glare treatment is an anti-glare layer provided on one surface of the base material.
[ appendix 15] the optical laminate according to appendix 14, wherein the antiglare layer is formed using an antiglare layer-forming material containing a resin, a particle, and a thixotropy-imparting agent,
the antiglare layer has an aggregate portion on the surface thereof, which forms a convex portion, by aggregating the particles and the thixotropic agent.
[ appendix 16] the optical laminate according to appendix 15, wherein the convex portion on the surface of the antiglare layer has an average inclination angle θ a (°) in a range from 0.1 to 1.5.
[ appendix 17] the optical laminate according to any one of appendix 1 to 16, further comprising a surface protection film laminated on a surface of the substrate on which the second pressure-sensitive adhesive layer is not laminated.
[ additional note 18] A self-light-emitting type display device, comprising:
display panel having a plurality of light-emitting elements arranged on one surface of substrate, and display device
The optical laminate according to any one of supplementary notes 1 to 17,
the surface of the display panel on which the light-emitting elements are arranged is laminated with the first adhesive layer of the optical laminate.
[ supplementary note 19] the self-luminous display device according to supplementary note 18, wherein the display panel is an LED panel having a plurality of LED chips arranged on one surface of a substrate.
Industrial applicability
The optical laminate of the present invention is suitable for encapsulating light emitting elements of a self-light emitting display device such as a Mini/Micro LED.
Description of the reference numerals
10. 11, 12 optical laminate
1. First adhesive layer
2. Second adhesive layer
3. Base material
4. Anti-reflection and/or anti-glare treatments
4a antiglare layer
20. 21, 22 self-luminous display device (Mini/Micro LED display device)
5. Substrate
6. Metal wiring layer
7. Light emitting element (LED chip).

Claims (19)

1. An optical laminate having a laminate structure in which a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer and a base material are laminated in this order,
a visible light transmittance T of the first adhesive layer 1 And a visible light transmittance T of the second adhesive layer 2 Satisfy T 1 <T 2 。
2. The optical laminate of claim 1, wherein the first adhesive layer has a visible light transmission T 1 And the visible light transmittance T of the base material 3 Satisfy T 1 <T 3 。
3. The optical laminate of claim 1 or 2, wherein the first adhesive layer has a visible light transmission T 1 Is 80% or less.
4. The optical laminate of any one of claims 1-3, wherein the second adhesive layer has a visible light transmission T 2 Is 85 to 100 percent.
5. The optical laminate according to any one of claims 1 to 4, wherein the first adhesive layer and the second adhesive layer are adhesive layers formed from an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition.
6. The optical laminate according to claim 5, wherein the adhesive composition forming said first adhesive layer contains a colorant.
7. The optical stack according to claim 5 or 6, wherein the adhesive composition comprises an acrylic polymer.
8. The optical stack according to claim 7, wherein said acrylic polymer comprises a (meth) acrylic block copolymer.
9. The optical laminate according to claim 8, wherein the adhesive composition forming the first adhesive layer is a solvent-based adhesive composition containing a (meth) acrylic block copolymer.
10. The optical stack according to any one of claims 1 to 9, wherein the thickness of the first adhesive layer is from 10 to 300 μ ι η.
11. The optical stack according to any one of claims 1 to 10, wherein the thickness of the second adhesive layer is from 1 to 500 μm.
12. The optical laminate according to any one of claims 1 to 11, wherein the ratio of the thickness of the second adhesive layer to the thickness of the first adhesive layer, i.e., the thickness of the second adhesive layer/the thickness of the first adhesive layer, is 1.0 to 5.0.
13. The optical laminate according to any one of claims 1 to 12, wherein a surface of the substrate on which the second adhesive layer is not laminated is subjected to an antireflection treatment and/or an antiglare treatment.
14. An optical stack according to claim 13, wherein the anti-glare treatment is an anti-glare layer disposed on a single side of the substrate.
15. The optical laminate according to claim 14, wherein the antiglare layer is formed using an antiglare layer-forming material comprising a resin, particles, and a thixotropy-imparting agent,
the antiglare layer has an aggregate portion on the surface thereof, which forms a convex portion, by aggregating the particles and the thixotropic agent.
16. The optical laminate according to claim 15, wherein an average inclination angle θ a (°) of the convex portion on the surface of the antiglare layer is in a range from 0.1 to 1.5.
17. The optical laminate according to any one of claims 1 to 16, further comprising a surface protective film laminated on the surface of the substrate on which the second adhesive layer is not laminated.
18. A self-luminous display device, comprising:
display panel having a plurality of light-emitting elements arranged on one surface of substrate, and display device
The optical stack according to any one of claims 1 to 17,
the surface of the display panel on which the light-emitting elements are arranged is laminated with the first adhesive layer of the optical laminate.
19. The self-luminous display device according to claim 18, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one surface of a substrate.
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