CN111849361B - Adhesive composition for optical use, and adhesive film and adhesive sheet each using the same - Google Patents

Adhesive composition for optical use, and adhesive film and adhesive sheet each using the same Download PDF

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Publication number
CN111849361B
CN111849361B CN202010327637.7A CN202010327637A CN111849361B CN 111849361 B CN111849361 B CN 111849361B CN 202010327637 A CN202010327637 A CN 202010327637A CN 111849361 B CN111849361 B CN 111849361B
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meth
adhesive
adhesive layer
acrylate
group
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CN111849361A (en
Inventor
长仓毅
铃木史惠
塚田高士
大津贺健太郎
吉田弘幸
广神萌美
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Fujimori Kogyo Co Ltd
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    • 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
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • C09J4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00
    • 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
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/46—Polymerisation initiated by wave energy or particle radiation
    • C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
    • C08F2/50—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light with sensitising agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F220/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
    • C08F220/285—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing a polyether chain in the alcohol moiety
    • C08F220/286—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing a polyether chain in the alcohol moiety and containing polyethylene oxide in the alcohol moiety, e.g. methoxy polyethylene glycol (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F220/30—Esters containing oxygen in addition to the carboxy oxygen containing aromatic rings in the alcohol moiety
    • C08F220/305—Esters containing oxygen in addition to the carboxy oxygen containing aromatic rings in the alcohol moiety and containing a polyether chain in the alcohol moiety
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—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 a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
    • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
    • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
    • C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
    • C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
    • 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
    • C09J151/00—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C09J151/06—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • 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
    • C09J7/10—Adhesives in the form of films or foils without 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
    • C09J7/22—Plastics; Metallised plastics
    • 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
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/255—Polyesters
    • 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]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/13338—Input devices, e.g. touch panels
    • 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
    • C09J2433/00—Presence of (meth)acrylic polymer
    • 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
    • C09J2451/00—Presence of graft polymer
    • 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
    • C09J2467/00—Presence of polyester
    • C09J2467/006—Presence of polyester in the substrate

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)
  • Polarising Elements (AREA)

Abstract

The invention provides an adhesive composition for optical use, which can form an adhesive layer having step following performance of step difference such as frame printing of an adherend, handling performance during re-operation and excellent wet heat durability, and an adhesive film and an adhesive sheet using the adhesive composition for optical use. The optical adhesive composition contains: a copolymer obtained by copolymerizing at least two or more kinds of compounds selected from the group consisting of a copolymerizable vinyl monomer having no carboxyl group in a functional group and having any one of an alkyl group, a hydroxyl group, an alkoxy group, and an aromatic group, and a nitrogen-containing vinyl monomer; (F) A monomer of a (meth) acrylic acid ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups; (G) A monomer of (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule; (E) a thermal crosslinking agent; and (H) a photocrosslinking agent.

Description

Adhesive composition for optical use, and adhesive film and adhesive sheet each using the same
Technical Field
The present invention relates to an adhesive composition for optical use, and an adhesive film and an adhesive sheet each using the same. More specifically, the present invention relates to an adhesive composition for optical use, which can form an adhesive layer having both of step following properties for a step such as frame printing of an adherend, handling properties (easy peeling from the adherend) during reworking, and excellent wet heat durability. Further, the present invention relates to an adhesive film and an adhesive sheet each using the adhesive composition for optical use.
The adhesive layer obtained by using the adhesive composition for optical use of the present invention and crosslinking the adhesive layer with a thermal crosslinking agent is excellent in level difference following property for level differences (irregularities) such as frame printing provided on the surface of an adherend and handling properties at the time of reworking. Further, the adhesive layer crosslinked by the two stages of crosslinking by the thermal crosslinking agent and subsequent crosslinking by the photocrosslinker is excellent in wet heat durability.
The adhesive composition for optical use, and the adhesive film and the adhesive sheet using the same according to the present invention can be used for bonding optical films to various displays, bonding optical films to each other to produce a laminate of optical films, and fixing various optical components and electronic components mounted on electronic devices.
In the present invention, the term "wet heat durability" of the adhesive layer means durability such that no significant foaming by moisture occurs and transparency can be maintained even when the adhesive layer is taken out to room temperature (temperature 23 ℃ c.×50% rh) after being left in a wet heat environment for a long period of time.
Background
In recent years, electronic devices that combine a display (image display device) and a touch panel as an input device have been widespread. As a display (image display device) to which the touch panel is applied, a Liquid Crystal Display (LCD), an electroluminescent display (inorganic EL, organic EL), or the like can be cited. Specific examples of the electronic device using the touch panel as an input device include a liquid crystal television, an inorganic EL television, an organic EL television, a mobile terminal, a mobile phone, electronic paper, an electronic book terminal, and a computer.
In these electronic devices, an adhesive layer for bonding optical members constituting a touch panel is required to have functions such as step-following property and wet heat durability.
Conventionally, various proposals have been made for obtaining an adhesive layer having step-following properties (patent documents 1 to 3). Further, an adhesive layer having step following property and wet heat durability has been proposed (patent document 4).
Patent document 1 describes a double-sided adhesive sheet which has excellent adhesion to a step caused by a decorative portion provided on the surface of a transparent panel or the surface of an image display device when the transparent panel and the image display device are fixed, and which can suppress foaming and peeling of the step portion in a high-temperature environment.
Patent document 2 describes a surface protective film with a decorative printed layer, which has few bubbles at the printed edge due to the difference in print level when forming an adhesive layer, and which does not generate bubbles when attached to an adherend, and which is less likely to generate dents even when a load is applied.
Patent document 3 describes a photopolymerizable adhesive for use in a touch panel having a conductive film made of a metal or a metal oxide, which is excellent in moisture and heat stability and foaming resistance, and which is free from occurrence of whitening and foaming, smell and skin irritation, and further free from corrosiveness to the metal or the metal oxide, and an adhesive sheet using the same.
Patent document 4 describes an acrylic polymer compound used for an adhesive composition for a touch panel, which is excellent in transparency, adhesion, durability, corrosion resistance, step-following property, high dielectric constant, and coatability.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2012-211282
Patent document 2: japanese patent application laid-open No. 2015-221531
Patent document 3: japanese patent laid-open No. 2013-256552
Patent document 4: japanese patent application laid-open No. 2012-04456
Disclosure of Invention
Technical problem to be solved by the invention
The double-sided adhesive sheet described in patent document 1 satisfies performance related to the following property of the printing stage difference because the value of the storage modulus of the adhesive layer is controlled within a specific numerical range and a soft adhesive layer is produced. However, if the adhesive force of the adhesive layer is increased, when the optical member is required to be reattached after the optical member is attached to the adherend, the optical member may be less likely to be peeled off, and the handling performance (reattachability) at the time of so-called reattachment may be poor. In contrast, if the handling performance at the time of reworking the adhesive layer is improved, the adhesive force after the optical member is attached to the adherend is too low, and peeling may occur. Therefore, the double-sided adhesive sheet described in patent document 1 has a problem that it is difficult to achieve both of ensuring handling performance at the time of reworking of the adhesive layer and improving adhesive force after bonding of the optical member to the adherend.
Patent document 2 discloses that a decorative printed layer such as a pattern or a letter is formed on one surface of a transparent resin film, a photocurable resin composition containing a photopolymerization initiator and having fluidity is applied to an upper portion of a portion where the decorative printed layer is not formed and an upper portion of the decorative printed layer, and then UV irradiation is performed to form a photocurable adhesive layer, thereby obtaining a surface protective film with the decorative printed layer. The surface protective film with a decorative printed layer of patent document 2 is capable of embedding a printed level difference regardless of flexibility of the adhesive layer after UV curing, because the adhesive layer is formed by UV irradiation after applying a photocurable resin composition containing a photopolymerization initiator and having fluidity. However, since the adhesive composition in a liquid form is applied, the adhesive layer of the invention of patent document 2 has a problem that it is difficult to form a thick film adhesive layer. Further, coating a liquid photocurable resin composition on the portion of the printing level difference to embed the printing level difference has a technical problem of troublesome operation.
Further, patent document 3 discloses a photopolymerizable adhesive comprising 40 to 92% by weight of (a-1) (meth) acrylic acid alkyl ester, 5 to 20% by weight of (a-2) hydroxyl group-containing monomer, 3 to 25% by weight of (a-3) water-soluble N-substituted acrylamide, and 0.01 to 2 parts by weight of isocyanate-based crosslinking agent and/or polyfunctional monomer (B) and 0.1 to 2 parts by weight of photopolymerization initiator (C) per 100 parts by weight of monomer group (a) substantially not containing acidic group-containing monomer (100% by weight of total monomer) or part of polymer (a') thereof. In the case of the photopolymerizable adhesive of patent document 3, the level difference tracking property and the re-peeling property are good. According to examples 1 to 6 of patent document 3, a photopolymerizable adhesive was applied to a substrate to form a coating film having a thickness of 300 μm, a release-treated PET film having a thickness of 25 μm was provided on the surface of the coating film so that the release-treated surface was in contact with the surface of the coating film, and photopolymerization was performed by UV irradiation under a nitrogen atmosphere to produce an adhesive sheet. However, since the adhesive force of the obtained adhesive sheet is in the range of 14 to 25N/25mm, when the adhesive sheet attached to the adherend is reattached, the adhesive sheet is hardly peeled off from the adherend, and there is a problem that handling performance at the time of reworking is poor.
Patent document 4 discloses an acrylic polymer compound used in an adhesive composition for a touch panel, which is obtained by copolymerizing a monomer component comprising (a) a (meth) acrylic acid ester monomer having a hydrocarbon group having 1 to 12 carbon atoms, (b) a hydroxyl group-containing (meth) acrylic acid ester monomer, (c) an amide group-containing monomer and (d) a vinyl ester monomer, wherein the polymer compound has a resin acid value of 0.1mgKOH/g or less, a weight average molecular weight of 40 to 200 ten thousand, a Tg of-80 to 0 ℃, and a dielectric constant of 3 to 6. Among the acrylic polymer compounds of patent document 4, "hydroxyl group-containing acrylate monomers are preferable, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularly preferable because the polymer compound can be given a functional group at a reaction site with a crosslinking agent, and a crosslinked product obtained by crosslinking can impart appropriate elasticity as an adhesive agent and improve cohesive force, and at the same time, improve dielectric constant, and further contribute to improvement of moist heat resistance of an adhesive sheet (see [0021] of document 4).
In the adhesive sheet of patent document 4, "a printed layer is often provided on a protective transparent plate in order to improve the design of the product and to make the product different. The printing ink layer, a layer of silver paste for various circuits, and a level difference of about 10 to 30 μm such as a level difference generated in the FPD part are often provided on the base sheet or film, and there is a problem that bubbles are generated when the adhesive sheet is used for bonding. This is caused by the lack of step following property of the adhesive layer. This step-following property is closely related to the proper Tg and gel fraction among the adhesive properties of the adhesive sheet obtained from the adhesive composition. The gel fraction of the adhesive is preferably about 30 to 70%, more preferably about 40 to 65% (see paragraph [0081] of reference 4).
However, in the adhesive sheets of examples 1 to 12 of the cited document 4, although the thickness of the adhesive layers of the adhesive sheets of examples 1, 2, 5, 6, 8, 10 is as thin as 50 μm, there is a problem that the haze value after the wet heat resistance test exceeds 4.0%, and thus further improvement in wet heat resistance is required.
As described above, it is difficult to obtain an optical adhesive composition that can form an adhesive layer having excellent wet heat durability and having good step following property against a step such as frame printing of an adherend and good handling property at the time of reworking, and an adhesive film and an adhesive sheet using the optical adhesive composition.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an adhesive composition for optical use, which can form an adhesive layer having both of step following property against a step such as frame printing of an adherend, handling property at the time of reworking, and excellent wet heat durability, and an adhesive film and an adhesive sheet using the adhesive composition for optical use.
Technical means for solving the technical problems
The inventors of the present application have studied intensively on the above-mentioned technical problems, and have found that an adhesive layer (first stage) formed by crosslinking an optical adhesive composition with a thermal crosslinking agent, which is excellent in step-following property and handling property at the time of reworking, before crosslinking with a photocrosslinker, and an adhesive layer (second stage) formed by crosslinking the optical adhesive composition through two stages of crosslinking with the thermal crosslinking agent and subsequent photocrosslinker, have excellent wet-heat durability, and have completed the present invention. The optical adhesive composition contains: an acrylic polymer; a monomer of a (meth) acrylic acid ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups; a monomer of (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule; a thermal crosslinking agent; and a photocrosslinking agent.
The optical adhesive composition of the present invention has the following characteristics: by crosslinking the acrylic polymer, the monomer of the (meth) acrylic ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups, the monomer of the (meth) acrylic ester having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule, the thermal crosslinking agent, and the optical adhesive composition of the photo crosslinking agent in two stages, an adhesive layer having different physical properties can be formed.
That is, the technical idea of the present invention is to provide an adhesive composition for optical use capable of forming an adhesive layer having different physical properties including a first-stage adhesive layer having a step following property against a step difference such as frame printing of an adherend and good handling properties at the time of reworking, and a second-stage adhesive layer having excellent wet heat durability, and an adhesive film and an adhesive sheet using the same.
In order to solve the above-mentioned problems, the present invention provides an optical adhesive composition comprising: a copolymer obtained by copolymerizing at least two or more kinds of compounds selected from the group consisting of a copolymerizable vinyl monomer having no carboxyl group in a functional group and having any one of an alkyl group, a hydroxyl group, an alkoxy group, and an aromatic group, and a nitrogen-containing vinyl monomer; (F) A monomer of a (meth) acrylic acid ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups; (G) A monomer of (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule; (E) a thermal crosslinking agent; and (H) a photocrosslinking agent.
Furthermore, it is preferable that: the copolymer is a copolymer having a weight average molecular weight of 20 to 100 tens of thousands, and is produced by copolymerizing 2.0 to 10 parts by weight of at least one or more of (B) nitrogen-containing vinyl monomers or alkoxy-containing alkyl (meth) acrylate monomers, 1.0 to 10 parts by weight of at least one or more of (C) polyalkylene glycol mono (meth) acrylate monomers, and 0.5 to 10 parts by weight of at least one or more of (D) copolymerizable vinyl monomers having a hydroxyl group, based on 100 parts by weight of (A) alkyl (meth) acrylate monomers; the optical adhesive composition contains the thermal crosslinking agent (E) in a proportion of 0.01 to 5 parts by weight, the monomer (F) of the (meth) acrylic ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups in a proportion of 0.1 to 10 parts by weight, the monomer (G) of the (meth) acrylic ester having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule in a proportion of 0.01 to 5 parts by weight, and the photocrosslinking agent (H) in a proportion of 0.1 to 10 parts by weight relative to 100 parts by weight of the (A).
Furthermore, it is preferable that: the adhesive layer having a thickness of 250 [ mu ] m formed by crosslinking the optical adhesive composition in two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent has a total light transmittance of 90% or more and a haze value of 1.0% or less.
Furthermore, it is preferable that: the optical adhesive composition is crosslinked to form an adhesive layer having a thickness of 250 [ mu ] m by two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent, and the adhesive layer is left for 240 hours under an atmosphere having a temperature of 60 ℃ x 90% RH and then taken out to have a haze value of 4.0% or less when it is brought into a room temperature environment (a temperature of 23 ℃ x 50% RH).
Further, it is preferable that the copolymer contains an alkyl (meth) acrylate having an alkyl group of a carbon number of from C8 to C18 in a proportion of 50 parts by weight or more in at least one or more of the alkyl (meth) acrylate monomers having an alkyl group of a carbon number of from C1 to C18 in a total of 100 parts by weight of (a).
Furthermore, it is preferable that: the copolymer is obtained by copolymerizing (C) a polyalkylene glycol mono (meth) acrylate monomer, and the optical adhesive composition contains (G) a monomer of a (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule, and the average number of repetitions of the alkylene oxide groups of (C) and (G) is preferably 4 to 14.
The present invention also provides an adhesive film comprising a substrate and an adhesive layer laminated on one surface of the substrate, wherein the adhesive layer is formed by crosslinking the adhesive composition with the (E) thermal crosslinking agent or by crosslinking the adhesive composition with the (E) thermal crosslinking agent and subsequent crosslinking with the (H) photo crosslinking agent; the adhesive layer crosslinked by the (E) thermal crosslinking agent has an adhesive force to soda-lime glass of 10N/25mm or less, and the adhesive layer crosslinked by the (E) thermal crosslinking agent and the subsequent crosslinking by the (H) photo crosslinking agent has an adhesive force to soda-lime glass of 25N/25mm or more.
The present invention also provides an adhesive film comprising an adhesive layer laminated on one side of a polyethylene phthalate resin film having a thickness of 188 μm, wherein the adhesive layer is formed by using the above-mentioned adhesive composition for optical use and crosslinking the adhesive layer with the above-mentioned (E) thermal crosslinking agent; when the adhesive film is bonded to a glass having a print level difference of a print layer having a thickness of 42 μm via the adhesive layer having a thickness of 100 μm, the following property with respect to the print level difference is good, and no blister is generated around the print level difference.
The present invention also provides a film for a touch panel using the adhesive film.
The present invention also provides an adhesive sheet obtained by laminating an adhesive layer obtained by crosslinking the above-mentioned adhesive composition for optical use with the above-mentioned (E) thermal crosslinking agent between two release films subjected to release treatment.
The present invention also provides an optical film with an adhesive layer formed by laminating an adhesive layer on at least one surface of an optical film, wherein the adhesive layer is formed by crosslinking the adhesive composition for optical use with the (E) thermal crosslinking agent, or by crosslinking the adhesive composition for optical use with the (E) thermal crosslinking agent and subsequent crosslinking with the (H) photo crosslinking agent.
Effects of the invention
The optical adhesive composition of the present invention is an optical adhesive composition comprising an acrylic polymer, a monomer of a (meth) acrylate having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups, a monomer of a (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule, a thermal crosslinking agent, and a photocrosslinker. Here, when a monomer of a (meth) acrylate having a (meth) acryloyl group and an allyl ether group in one molecule and two or more ethylenically unsaturated groups is photocrosslinked with a photocrosslinker, a cyclic compound is formed, and therefore, the adhesive layer crosslinked in two stages of crosslinking by a thermal crosslinking agent and subsequent crosslinking by a photocrosslinker has excellent wet heat durability.
The adhesive film and the adhesive sheet of the present invention are each provided with an adhesive layer crosslinked by an optical adhesive composition comprising an acrylic polymer, a monomer of a (meth) acrylate having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups, a monomer of a (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule, a thermal crosslinking agent, and a photocrosslinking agent. The adhesive layer is an adhesive layer which is crosslinked by a thermal crosslinking agent and can be crosslinked in two stages of crosslinking by the thermal crosslinking agent and subsequent crosslinking by the photocrosslinker, or an adhesive layer which has been crosslinked in two stages of crosslinking by the thermal crosslinking agent and subsequent crosslinking by the photocrosslinker.
Therefore, according to the present invention, it is possible to provide an adhesive film and an adhesive sheet which have both of step following property against a step such as frame printing of an adherend, handling property at the time of re-handling, and excellent wet heat durability.
Detailed Description
The present invention will be described below based on preferred embodiments.
The optical adhesive composition of the present embodiment is characterized by comprising: a copolymer obtained by copolymerizing at least two or more kinds of compounds selected from the group consisting of a copolymerizable vinyl monomer having no carboxyl group in a functional group and having any one of an alkyl group, a hydroxyl group, an alkoxy group, and an aromatic group, and a nitrogen-containing vinyl monomer; (F) A monomer of a (meth) acrylic acid ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups; (G) A monomer of (meth) acrylate having an alkylene oxide group and having two or more ethylenically unsaturated groups in one molecule; (E) a thermal crosslinking agent; and (H) a photocrosslinking agent.
In the present specification, (meth) acrylate is a generic term for acrylate and methacrylate. The term "meth" acryl "refers to a general term" acryl "or" methacryl ". The copolymer of the optical adhesive composition of the present embodiment is, for example, a copolymer obtained by copolymerizing (a) at least one or more of alkyl (meth) acrylate monomers having an alkyl group of 1 to 18 carbon atoms, (B) at least one or more of nitrogen-containing vinyl monomers or alkoxy-containing alkyl (meth) acrylate monomers, (C) at least one or more of polyalkylene glycol mono (meth) acrylate monomers, and (D) at least one or more of copolymerizable vinyl monomers having a hydroxyl group.
Examples of the alkyl (meth) acrylate monomer having a carbon number of the alkyl group (a) of 1 to 18 include at least one of methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, and the like. The alkyl group of the alkyl (meth) acrylate monomer may be any of linear, branched, and cyclic. In the case where the presence of a branch is not specified, a specific compound belonging to a linear alkyl (meth) acrylate monomer having a carbon number of 3 or more may be referred to simply as propyl (meth) acrylate, butyl (meth) acrylate, or the like.
In the above (a), examples of the branched alkyl acrylate monomer (branched alkyl group-containing monomer) include at least one of isopropyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isopentyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) acrylate, isoundecyl (meth) acrylate, isododecyl (meth) acrylate, isotridecyl (meth) acrylate, isotetradecyl (meth) acrylate, isopentyl (meth) acrylate, isohexadecyl (meth) acrylate, isoheptadecyl (meth) acrylate, isooctadecyl (meth) acrylate, isomyristyl (meth) acrylate, and isostearyl (meth) acrylate. The branched alkyl group-containing monomer may have a branched structure having 2 or more alkyl groups (for example, having 2 or more side chains in the main chain), such as t-butyl.
In the above (a), as the cyclic alkyl acrylate monomer (alicyclic-containing monomer), at least one or more of cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, bicycloheptyl (meth) acrylate, bicyclooctyl (meth) acrylate, dimethylbicycloheptyl (meth) acrylate, dicyclopentyl (meth) acrylate and the like are exemplified.
In at least one of the alkyl (meth) acrylate monomers having a carbon number of C1 to C18 in the total of 100 parts by weight of the (A) alkyl group, the ratio of the alkyl (meth) acrylate having a carbon number of C8 to C18 in the alkyl group is preferably 50 parts by weight or more. Among alkyl (meth) acrylates having an alkyl group of 8 to 18 carbon atoms, monomers having a branched alkyl group such as isooctyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.
The nitrogen-containing vinyl monomer in (B) may be at least one of an amide bond-containing vinyl monomer, an amino group-containing vinyl monomer, a vinyl monomer having a nitrogen-containing heterocyclic structure, and the like. The nitrogen-containing vinyl monomer is preferably a nitrogen-containing vinyl monomer containing no hydroxyl group, and more preferably a nitrogen-containing vinyl monomer containing no hydroxyl group or carboxyl group. As such a monomer, preferred are the monomers exemplified above, such as an acrylic monomer containing an N, N-dialkyl-substituted amino group or an N, N-dialkyl-substituted amide group; n-vinyl substituted lactams such as N-vinyl-2-pyrrolidone, N-vinyl caprolactam, and N-vinyl-2-piperidone; n- (meth) acryl substituted cyclic amines such as N- (meth) acryl morpholine and N- (meth) acryl pyrrolidine.
Examples of the N, N-dialkyl substituted amino group-containing acrylic monomer include dialkylamino (meth) acrylates such as dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminoisopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate, diethylaminomethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N-propylaminoethyl (meth) acrylate, N-methyl-N-isopropylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, and the like; n, N-dialkyl substituted aminoalkyl-containing (meth) acrylamides such as dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, dipropylaminopropyl (meth) acrylamide, diisopropylaminopropyl (meth) acrylamide, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide, and the like.
Examples of the N, N-dialkyl-substituted amide group-containing acrylic monomer include dialkyl-substituted (meth) acrylamides such as dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dipropyl acrylamide, diisopropyl (meth) acrylamide, dibutyl (meth) acrylamide, N-ethyl-N-methyl (meth) acrylamide, N-methyl-N-propyl (meth) acrylamide, and N-methyl-N-isopropyl (meth) acrylamide.
Examples of the N-vinyl-substituted lactams include N-vinylpyrrolidone, methyl vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, and N-vinyldodecalactam.
Examples of the N-vinyl-substituted heterocyclic vinyl compound include N-vinylpyridine, N-vinylpiperazine, N-vinylpyrzine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, and N-vinylmorpholine.
Examples of the N- (meth) acryl-substituted cyclic amine include N- (meth) acryloylmorpholine, N- (meth) acryloylpiperazine, N- (meth) acryloylaziridine, N- (meth) acryloylazetidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloylpiperidine, N- (meth) acryloylazepane, and N- (meth) acryloylazepane.
Examples of the other nitrogen-containing vinyl monomer include N-vinylcarboxylic acid amides such as N-vinylformamide, N-vinylacetamide, and N-vinyl-N-methylacetamide; (meth) acrylamides such as unsubstituted (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-t-butyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, N-methylenebis (meth) acrylamide, and the like; unsaturated carboxylic acid imides such as N-cyclohexylmaleimide and N-phenylmaleimide; unsaturated carboxylic acid nitriles such as (meth) acrylonitrile, and the like. Preferably, the nitrogen-containing vinyl monomer does not contain an isocyanate group. In addition, it is preferable that the nitrogen-containing vinyl monomer does not contain a quaternary cationic structure such as a quaternary ammonium salt. The nitrogen-containing vinyl monomer may contain a tertiary cationic structure neutralized with an N, N-dialkyl substituted amino group to such an extent that the nitrogen-containing vinyl monomer is not acidic.
Examples of the alkyl (meth) acrylate monomer having an alkoxy group in the above (B) include at least one of 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-isopropoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 2-propoxypropyl (meth) acrylate, 2-isopropoxypropyl (meth) acrylate, 2-butoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylic acid, 3-ethoxypropyl (meth) acrylate, 3-propoxypropyl (meth) acrylate, 3-isopropoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate, 4-propoxybutyl (meth) acrylate, 4-butoxybutyl (meth) acrylate, and the like. These alkoxy group-containing alkyl (meth) acrylate monomers have a structure in which an atom of an alkyl group in the alkyl (meth) acrylate is substituted with an alkoxy group.
In the copolymer, at least one of (B) a nitrogen-containing vinyl monomer and an alkoxy-containing alkyl (meth) acrylate monomer is copolymerized in a total of preferably 2.0 to 10 parts by weight, more preferably 2.0 to 9 parts by weight, and particularly preferably 2.5 to 9 parts by weight, based on 100 parts by weight of (A) at least one of the alkyl (meth) acrylate monomers having a carbon number of C1 to C18. Two or more nitrogen-containing vinyl monomers and alkoxy-containing alkyl (meth) acrylate monomers can be used separately or simultaneously.
The (C) polyalkylene glycol mono (meth) acrylate monomer may be a mono (meth) acrylate monomer having a polyalkylene glycol chain, and may be a compound in which one of a plurality of hydroxyl groups of a polyalkylene glycol is esterified to a (meth) acrylate. Since the (meth) acrylate group is a polymerizable group, it can be copolymerized with the copolymer. The other hydroxyl group may be OH, or may be an alkyl ether such as methyl ether or ethyl ether, or a saturated carboxylic acid ester such as acetic acid ester.
In the above (C), examples of the alkylene group included in the polyalkylene glycol include, but are not limited to, ethylene, propylene, and butylene. The polyalkylene glycol may be a polyalkylene glycol having 2 or more alkylene groups in one molecule, such as polyethylene glycol-polypropylene glycol, polyethylene glycol-polytetramethylene glycol, and polypropylene glycol-polytetramethylene glycol.
In the above (C), the average number of repetitions of alkylene oxide constituting the polyalkylene glycol chain is preferably 4 to 14. Herein, "average number of repetitions of alkylene oxide" refers to the average number of repetitions of alkylene oxide units in the portion of the "polyalkylene glycol chain".
The (C) is preferably at least one selected from the group consisting of polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, and ethoxy polyalkylene glycol (meth) acrylate. More specifically, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, ethoxypolytetramethylene glycol (meth) acrylate, and the like can be cited.
In the copolymer, at least one or more of the (C) polyalkylene glycol mono (meth) acrylate monomers is copolymerized in a total of 1.0 to 10 parts by weight, more preferably 1.5 to 9 parts by weight, and particularly preferably 2.0 to 9 parts by weight, based on 100 parts by weight of the (A) alkyl (meth) acrylate monomers having carbon atoms of C1 to C18.
Examples of the copolymerizable vinyl monomer having a hydroxyl group include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyl group-containing alkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, and at least one or more hydroxyl group-containing (meth) acrylamides such as N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide.
In the copolymer, at least one or more of (D) a copolymerizable vinyl monomer having a hydroxyl group is copolymerized in a total of 0.5 to 10 parts by weight, more preferably 0.8 to 9 parts by weight, and particularly preferably 0.8 to 8 parts by weight, based on 100 parts by weight of (a) an alkyl (meth) acrylate monomer having a carbon number of C1 to C18. When the (C) may have a hydroxyl group, it is preferable that the (D) has no polyalkylene glycol chain.
In the copolymer, a copolymerizable vinyl monomer having an aromatic group may be copolymerized in addition to at least one of the above (a) to (D). Examples of the copolymerizable vinyl monomer having an aromatic group include at least one or more aromatic group-containing (meth) acrylate monomers such as benzyl (meth) acrylate, naphthalene (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxybutyl (meth) acrylate, 2- (1-naphthoxy) ethyl (meth) acrylate, 2- (2-naphthoxy) ethyl (meth) acrylate, 6- (1-naphthoxy) hexyl (meth) acrylate, 6- (2-naphthoxy) hexyl (meth) acrylate, 8- (1-naphthoxy) octyl (meth) acrylate, and 8- (2-naphthoxy) octyl (meth) acrylate. The (A) to (D) may be copolymerizable vinyl monomers having no aromatic group.
The polymerization method of the copolymer is not particularly limited, and suitable and known polymerization methods such as a solution polymerization method and an emulsion polymerization method can be used. Preferably, the copolymer is an acrylic polymer containing 50 to 100% by weight of an acrylic monomer such as a (meth) acrylate monomer. Preferably, the copolymer has a weight average molecular weight of 20 to 100 tens of thousands. Preferably, the copolymer is a copolymer in which a copolymerizable vinyl monomer having a carboxyl group is not copolymerized. Further, from the viewpoint of suppressing the corrosiveness of the ITO surface of the transparent conductive film to an adherend that is easily corroded, it is preferable to prepare a copolymer that does not copolymerize a copolymerizable vinyl monomer having a carboxyl group, and thereby the acid value of the copolymer is set to 1.0 or less.
The thermal crosslinking agent (E) may be at least one of an isocyanate crosslinking agent, an epoxy crosslinking agent, an aluminum chelate crosslinking agent, and the like.
Examples of the isocyanate-based crosslinking agent include difunctional isocyanates (diisocyanate compounds) such as Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene Diisocyanate (TDI), and Xylylene Diisocyanate (XDI), and trifunctional or higher polyisocyanates (polyisocyanurate) such as biuret modified products, isocyanurate modified products, and adducts thereof. Examples of the trifunctional or higher adducts include adducts of diisocyanate compounds and tri-or higher polyols such as trimethylolpropane and glycerin. As the thermal crosslinking agent (E), only an isocyanate compound may be used.
The copolymer preferably has hydroxyl groups as functional groups which are reactive with the (E) thermal crosslinking agent, particularly preferably copolymerized with the (D).
The optical adhesive composition preferably contains the thermal crosslinking agent (E) in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the adhesive (a).
The (F) may be at least one or more of (meth) acrylate monomers having a (meth) acryloyl group and an allyl ether group in one molecule. Since the (meth) acryloyl group and the allyl ether group each have an ethylenically unsaturated group, the (F) has two or more ethylenically unsaturated groups. The number of (meth) acryloyl groups in one molecule is 1 or more than 2, and the number of allyl ether groups in one molecule is 1 or more than 2. The number of (meth) acryloyl groups and the number of allyl ether groups in the molecule of (F) may be different, but are preferably the same number.
In the adhesive composition for optical use of the present embodiment, the (F) has a function of remarkably improving the wet heat durability of the adhesive layer. The reason why the wet heat durability of the adhesive layer is significantly improved when the adhesive composition for optical use contains the above (F) is not clear, but one of the reasons is considered to be as follows.
The reason for this is that when the (F) is crosslinked by the (H) photocrosslinker, the (meth) acryloyl group and the allyl ether group form a cyclic structure. And it is presumed that, when the (F) is crosslinked by the (H) photocrosslinker, a polymer having a cyclic structure formed of a (meth) acryloyl group and an allyl ether group is formed, and/or a copolymer of the cyclic structure and the acrylic polymer is crosslinked or the like, whereby, in an adhesive layer left in a hot and humid environment for a long time, moisture in the hot and humid environment is enclosed inside the cyclic structure, free movement of moisture is prevented and foaming caused by moisture aggregation is suppressed even if the adhesive layer is thereafter taken out to room temperature environment (temperature 23 ℃ x 50% rh).
For the above reasons, it is considered that the adhesive layer crosslinked by the two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent has excellent wet heat durability. When the adhesive layer is formed by crosslinking the (F) with the (H) photocrosslinker, it is preferable that the adhesive layer crosslinked with the (E) thermal crosslinking agent contains the (F) and the (F) maintains reactivity of two or more ethylenically unsaturated groups in order to form a cyclic structure. Therefore, when crosslinking is performed by the (E) thermal crosslinking agent, the optical adhesive composition preferably does not contain a thermal polymerization initiator.
Further, as the (F), there may be mentioned alkyl (meth) acrylate containing an allyl ether group [ CH ] 2 ＝C(R 1 )COO-R 2 -OCH 2 CH＝CH 2 The method comprises the steps of carrying out a first treatment on the surface of the Here, R is 1 Is a hydrogen atom or methyl, R 2 Is a divalent group such as an alkylene group]Alkyl 2- (allyloxymethyl) acrylate [ CH 2 ＝CHCH 2 OCH 2 C(＝CH 2 ) COOR; here, R is an alkyl group]Etc. The cyclic structure is particularly preferably a five-membered ring or a six-membered ring which can form a high stability.
Specific examples of the (F) include allyloxyethyl (meth) acrylate, allyloxypropyl (meth) acrylate, methyl 2- (allyloxymethyl) acrylate, ethyl 2- (allyloxymethyl) acrylate, propyl 2- (allyloxymethyl) acrylate, butyl 2- (allyloxymethyl) acrylate, pentyl 2- (allyloxymethyl) acrylate, and hexyl 2- (allyloxymethyl) acrylate.
The optical adhesive composition preferably contains the (F) in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the (a).
The (G) may be at least one or more monomers of (meth) acrylic acid esters having an alkylene oxide group and two or more ethylenically unsaturated groups in one molecule.
The (G) may be, for example, a compound obtained by esterifying two or more hydroxyl groups out of a plurality of hydroxyl groups contained in an alkylene glycol (alkylene glycol), a polyalkylene glycol, or the like, into a (meth) acrylate.
In the above (G), the average number of repetitions of alkylene oxide constituting the polyalkylene glycol chain is preferably 4 to 14. Herein, the "average number of repetitions of alkylene oxide" refers to the average number of repetitions of alkylene oxide units in the portion of the "polyalkylene glycol chain". The average number of repetitions of the alkylene oxide of (G) may be the same as or different from the average number of repetitions of the alkylene oxide of (C).
In the above (G), the alkylene oxide group may be at least one of an ethylene oxide group, a propylene oxide group, a butylene oxide group, and the like. The alkylene oxide group of (G) may be the same as or different from the alkylene oxide group of (C). Specific examples of the (G) include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, and the like.
The optical adhesive composition preferably contains the (G) in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the (a).
Examples of the (H) photocrosslinker include photoinitiators such as a photo radical initiator. In order to crosslink the optical adhesive composition with the (E) thermal crosslinking agent and then crosslink the optical adhesive composition with the (H) photocrosslinker to form an adhesive layer, it is preferable that the (H) photocrosslinker maintains reactivity even at the stage after crosslinking with the (E) thermal crosslinking agent. Examples of such (H) photocrosslinkers include acetophenone photocrosslinkers, benzoin photocrosslinkers, benzophenone photocrosslinkers, thioxanthone photocrosslinkers, and acylphosphine oxide photocrosslinkers.
The optical adhesive composition preferably contains the (H) photocrosslinker in a proportion of 0.01 to 5 parts by weight relative to 100 parts by weight of the (a).
Examples of the acetophenone photocrosslinkers include acetophenone, p- (t-butyl) 1',1',1' -trichloroacetophenone, chloroacetophenone, 2' -diethoxyacetophenone, hydroxyacetophenone, 2-dimethoxy-2 ' -phenylacetophenone, 2-aminoacetophenone, dialkylaminoacetophenone, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one.
Examples of the benzoin photocrosslinkers include benzil, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-2-methylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, benzoin dimethyl ether, and 2, 2-dimethoxy-1, 2-diphenylethane-1-one.
Examples of the benzophenone photocrosslinkers include benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, methyl o-benzoyl benzoate, 4-phenyl benzophenone, hydroxybenzophenone, hydroxypropyl benzophenone, acrylic benzophenone, and 4,4' -bis (dimethylamino) benzophenone.
Examples of the thioxanthone photocrosslinkers include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, diethylthioxanthone, and dimethylthioxanthone.
Examples of the acylphosphine oxide photocrosslinkers include (2, 4, 6-trimethylbenzoyl) diphenylphosphine oxide and phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide.
Examples of the other photocrosslinkers include α -acyl oxime esters, benzyl- (o-ethoxycarbonyl) - α -monooxime, benzoyl formate, 3-coumarin, 2-ethyl anthraquinone, camphorquinone, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzoyl peroxide, dialkyl peroxide, t-butyl peroxypivalate, and the like.
The optical adhesive composition may contain, as optional components, known additives such as antioxidants, surfactants, curing accelerators, plasticizers, fillers, crosslinking catalysts, crosslinking retarders, curing retarders, processing aids, and aging inhibitors. These additives can be used singly or in combination of two or more.
The adhesive layer of the present embodiment can be produced by applying the optical adhesive composition to a substrate or a release film, and then crosslinking the optical adhesive composition by crosslinking the (E) thermal crosslinking agent and crosslinking the (H) photocrosslinking agent. In the adhesive layer of the present embodiment, the step following property of the adhesive layer (first stage) after crosslinking with the (E) thermal crosslinking agent and before crosslinking with the (H) photo crosslinking agent is excellent, and the handling property at the time of reworking is excellent. Further, the adhesive layer (second stage) obtained by crosslinking in two stages, i.e., crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent, is excellent in wet heat durability. The adhesive layer of the present embodiment may be bonded to the adherend in the first stage, or may be bonded to the adherend in the second stage, depending on the application, purpose, and the like.
The adhesive layer of the first stage contains the (H) photocrosslinker, and can be crosslinked by the (H) photocrosslinker. When the adhesive layer of the first stage is bonded to an adherend, the adhesive layer in a state of being bonded to the adherend may be crosslinked by the (H) photocrosslinking agent.
The energy rays irradiated when crosslinking is performed with the (H) photocrosslinker include ultraviolet rays and electron beams, and visible light and the like as the case may be, and ultraviolet rays are suitably used in terms of convenience. However, the present invention is not limited to ultraviolet rays. When the irradiation with energy rays is performed, the adhesive layer may be exposed, but if the release film or adherend laminated on the adhesive layer has a transmittance for energy rays, it is preferable to irradiate the adhesive layer with energy rays through the release film or adherend.
The adhesive composition for optical use of the present embodiment is preferably excellent in optical characteristics when it is used as an adhesive layer. The optical adhesive composition is preferably transparent. It is preferable that the function, the component, etc. of the additive do not impair the transparency (non-colorability) of the adhesive layer. In addition, it is preferable that the adhesive layer (the adhesive layer of the first stage or the adhesive layer of the second stage) made of the adhesive composition for optical use is transparent.
Specifically, the total light transmittance of the adhesive layer having a thickness of 250 μm formed by crosslinking the optical adhesive composition in two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent is preferably 90% or more, more preferably 91% or more.
Further, the haze value of the adhesive layer having a thickness of 250 μm formed by crosslinking the optical adhesive composition in two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent is preferably 1.0% or less, and more preferably 0.6% or less.
Further, the optical adhesive composition is crosslinked to form an adhesive layer having a thickness of 250 μm by two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent, and the adhesive layer is left for 240 hours under an atmosphere having a temperature of 60 ℃ x relative humidity of 90% rh, and then taken out to room temperature environment (a temperature of 23 ℃ x 50% rh) to have a haze value of preferably 4.0% or less, more preferably 3.5% or less.
The adhesive force of the adhesive layer after crosslinking with the (E) thermal crosslinking agent (before crosslinking with the (H) photocrosslinking agent) to soda lime glass is preferably 10N/25mm or less. This can improve handling performance during reworking of the adhesive layer.
Further, the adhesive force of the adhesive layer crosslinked by the two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photo crosslinking agent to soda lime glass is preferably 25N/25mm or more. When the adhesive layer of the first stage is bonded to an adherend and then crosslinked with the (H) photocrosslinker, high adhesive force can be obtained in the same manner as in the case of manufacturing the adhesive layer of the second stage and then bonding to the adherend.
In the case of an adhesive film formed by laminating an adhesive layer on one surface of a polyethylene phthalate resin film having a thickness of 188 μm, when the adhesive film is bonded to a glass having a print level difference having a print layer having a thickness of 42 μm via the adhesive layer having a thickness of 100 μm, it is preferable that the adhesive film has good following property with respect to the print level difference and no foaming is caused at all around the print level difference. The adhesive layer is formed by using the optical adhesive composition and crosslinking with the (E) thermal crosslinking agent.
The adhesive film and the adhesive sheet according to the present embodiment can be produced by forming the adhesive layer on one surface of a base material or a release film. In addition, in the 2015 edition of JIS Z0109 (adhesive tape/sheet term), the term "adhesive sheet" is defined as "a generic term of a plate-shaped article having an adhesive layer provided on one side or both sides of a substrate and a release liner attached thereto", and the term "adhesive tape" is defined as "a generic term of an article having an adhesive layer provided on one side or both sides of a substrate and wound into a roll shape", but the adhesive film and the adhesive sheet of the present embodiment are not limited thereto. The thickness of the adhesive layer in the adhesive film and the adhesive sheet is not particularly limited, and is preferably, for example, 10 to 3000 μm, more preferably 50 to 2000 μm.
As a base film for forming the adhesive layer or a release film (separation film) for protecting the adhesive surface, a resin film such as a polyester film or the like can be used.
In the base film, an antistatic treatment such as coating or kneading with an antistatic agent can be performed on the surface of the resin film opposite to the side on which the adhesive layer is formed, by an antifouling treatment with silicone-based or fluorine-based release agent, coating agent, silica fine particles, or the like.
In the release film, the surface on the side to be bonded to the adhesive surface of the adhesive layer may be subjected to a release treatment using a silicone-based or fluorine-based release agent or the like. By bonding the release-treated surfaces of the release film to the two surfaces of one adhesive layer, it is possible to produce an adhesive sheet having a structure of "release film/adhesive layer/release film". In this case, the release films on both sides are peeled off sequentially or simultaneously to expose the adhesive surface, whereby an optical member such as an optical film can be bonded to an adherend such as glass. Examples of the optical film include a polarizing film, a retardation film, an antireflection film, an antiglare (anti-glare) film, an ultraviolet light absorbing film, an infrared light absorbing film, an optical compensation film, and a brightness enhancement film.
The adhesive layer can obtain good step following property even in the bonding of glass such as cover glass (cover glass) and sensor glass (sensor glass), and therefore can be suitably used in the bonding of the cover glass and sensor glass of a touch panel. In the case of bonding the film member and the glass member, the adhesive film obtained by laminating the adhesive layer on one surface of the film member may be bonded to a glass member such as cover glass or sensor glass. The adhesive layer and the adhesive film are preferably used as an adhesive layer for a touch panel and an adhesive film for a touch panel. As a film for a touch panel using the adhesive film, various optical films for a touch panel described later and the like are exemplified in addition to the adhesive film for a touch panel.
The adhesive film and the adhesive sheet can be used for bonding various optical films for surrounding members of a liquid crystal display device including a polarizing plate, various optical films for a touch panel, various optical films for electronic paper, various optical films for organic EL, and the like.
In addition, an adhesive layer-attached optical film in which the adhesive layer is laminated on at least one surface of these optical films can be produced. Specifically, the composition may be "optical film/adhesive layer/optical film", "optical film/adhesive layer/release film", "optical film/adhesive layer/optical film", "optical film/adhesive layer/release film", "release film/adhesive layer/optical film/adhesive layer/release film", or the like.
For example, when the release film is peeled off to expose the adhesive layer as an "optical film/adhesive layer" and attach it to another optical film, the configuration of an "optical film/adhesive layer/optical film" in which the adhesive layer is used for interlayer attachment can be obtained.
The adhesive film and the adhesive sheet are suitably used for bonding a polarizing plate and a display panel. Examples of the display panel include a liquid crystal panel and an organic EL panel. The adhesive film and the adhesive sheet can be suitably used as an adhesive layer of a polarizing plate with an adhesive layer. As a constituent material of the polarizing plate, a retardation film having a retardation of λ/4 or λ/2 may be used. The adhesive layer can be used when bonding the retardation film and the polarizing plate. According to the adhesive film and the adhesive sheet, since the adhesive layer has a low dielectric constant, the adhesive film and the adhesive sheet can be suitably used for bonding an optical member between a polarizing plate and a backlight unit in an On-cell display device in which a touch sensor is provided between the color filter and the polarizing plate. In addition, the adhesive film and the adhesive sheet can be used when fixedly mounted on optical components and electronic components of various electronic devices.
Examples
The present invention will be specifically described below with reference to examples.
< preparation of acrylic Polymer >
Example 1
Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube, and air in the reaction apparatus was replaced with nitrogen gas. Then, 70 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of ethyl acrylate, 20 parts by weight of isobornyl acrylate, 5 parts by weight of N-vinylpyrrolidone, 4 parts by weight of polypropylene glycol monoacrylate (average number of repetitions of alkylene oxide n=12), 3.0 parts by weight of 6-hydroxyhexyl acrylate and 60 parts by weight of a solvent (ethyl acetate) were added to the reaction apparatus. Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and reacted at 65℃for 6 hours to obtain an acrylic polymer solution used in example 1.
Examples 2 to 5 and comparative examples 1 to 3
Acrylic polymer solutions used in examples 2 to 5 and comparative examples 1 to 3 were obtained in the same manner as the acrylic polymer solution used in example 1 described above, except that the compositions of the monomers were set forth in the descriptions of groups (a) to (D) of table 1, respectively.
Adhesive composition, adhesive layer and preparation of adhesive sheet
Example 1
To the acrylic polymer solution of example 1 prepared in the above manner, 0.5 parts by weight of CORONATE HX, 5 parts by weight of methyl 2- (allyloxymethyl) acrylate, 5 parts by weight of polyethylene glycol diacrylate (average repetition number of alkylene oxide n=4), 0.5 parts by weight of photo-crosslinking agent (Omnirad (registered trademark) 184) were added, and stirred and mixed to obtain an adhesive composition of example 1. The adhesive composition was applied to a release film (1) (a polyethylene terephthalate (PET) film having a thickness of 100 μm and coated with a silicone resin as a release agent layer) so that the thickness of the adhesive layer after drying became a predetermined value, and then dried at 90 ℃ to remove the solvent, and then cured for 7 days in an atmosphere of 23 ℃ and 50% rh to crosslink the adhesive composition with a thermal crosslinking agent, thereby forming an adhesive layer. Further, a release film (2) having a release agent layer with a release force lighter than that of the release film (1) and a thickness of 75 μm of the base material was bonded to the surface of the adhesive layer, to obtain an adhesive sheet a (adhesive layer in the first stage) of example 1 composed of the release film (1)/the adhesive layer/the release film (2). The adhesive layer crosslinked by the thermally advantageous crosslinking agent is further irradiated with Ultraviolet (UV) and crosslinked by the photocrosslinker. Thus, an adhesive sheet B (adhesive layer of the second stage was formed) of example 1 in which an adhesive layer was sandwiched between two release films, and the adhesive layer was formed by performing two stages of crosslinking by thermal crosslinking and crosslinking by photo crosslinking.
Examples 2 to 5 and comparative examples 1 to 3
The adhesive sheets a to B of examples 2 to 5 and comparative examples 1 to 3 were obtained in the same manner as the adhesive sheets a to B of example 1 described above, except that the compositions of the additives were set forth in the groups (E) to (H) of table 1, respectively.
TABLE 1
Table 1 shows the values of the parts by weight obtained by setting the total of the group (a) to 100 parts by weight. In addition, table 2 shows the compound names of abbreviations of the respective components used in table 1. Further, CORONATE (registered trademark) is a trade name of TOSOH CORPORATION, durarate (registered trademark) is a trade name of Asahi Kasei Corporation, omnirad (registered trademark) is a trade name of IGM Resins b.v. Omnirad 184 is a photocrosslinker containing 1-hydroxycyclohexyl phenyl ketone as a main component. Omnirad 651 is a photocrosslinker comprising 2, 2-dimethoxy-2-phenylacetophenone as a main component. Omnirad TPO is a photocrosslinker comprising (2, 4, 6-trimethylbenzoyl) diphenylphosphine oxide as a main component.
TABLE 2
Test method and evaluation
Release films (1) to (2) were peeled off from the adhesive sheets a to B in examples 1 to 5 and comparative examples 1 to 3 as needed to expose the adhesive layers, and evaluated by the following test methods and measurement methods.
In addition, the adhesive sheets a to B of examples 1 to 5 and comparative examples 1 to 3 were prepared to have different thicknesses of the adhesive layers in order to meet the following measurement method and test method, and further, the adhesive sheets a having the adhesive layer of the first stage or the adhesive sheets B having the adhesive layer of the second stage were formed. When the adhesive layer of the first stage was tested, an adhesive sheet a was used. In addition, the adhesive sheet B was used in the test of the adhesive layer in the second stage.
Method for measuring total light transmittance
The method for measuring the light transmittance comprises the following steps: the total light transmittance (%) of the adhesive layer (adhesive layer of the second stage) having a thickness of 250 μm was measured by JIS K7105, "optical property test method of plastic", and is recorded as "total light transmittance" in Table 3.
Method for measuring haze value
Method for measuring haze value: the haze value (%) of the adhesive layer (adhesive layer in the second stage) having a thickness of 250 μm was measured by JIS K7136, "determination method of haze of plastic-transparent material", and is reported as "initial haze value" in Table 3. Further, the mixture was left under an atmosphere of 60℃X 90% RH for 240 hours, and then taken out to room temperature (23℃and 50% RH). Five minutes after removal, the haze value (%) was measured in a state where both sides of the adhesive layer were covered with the release films (1) to (2), and the haze value after wet heat was recorded as "haze value after wet heat" in table 3.
< evaluation of damp-heat durability >
The wet heat durability of the adhesive layers formed on the adhesive sheets B in examples 1 to 5 and comparative examples 1 to 3 was evaluated using the "haze value after wet heat" measured by the above-described haze value measurement method. The wet heat durability determination criteria were set as follows, and the evaluation results thereof were recorded as "wet heat durability" in table 3.
O: the "haze value after wet heat" is 4.0% or less.
Delta: the "haze value after wet heat" exceeds 4.0% and is 6.0% or less.
X: the "haze value after damp heat" exceeds 6.0%.
Method for measuring adhesive force
An adhesive layer (adhesive layer in the first stage or adhesive layer in the second stage) having a thickness of 175 μm was transferred from the adhesive sheets a to B onto one side of a polyester film having a thickness of 50 μm, to obtain an adhesive film (optical film with adhesive layer) as a sample. The adhesive films thus obtained were bonded to the non-tin surface of alkali-free glass washed with acetone by a press roll, and subjected to autoclave treatment at 50℃under 0.5 MPa.times.20 minutes, and then returned to an air atmosphere of 23℃.times.50% RH for 1 hour. The peel strength of the adhesive film after the peeling was measured by a tensile tester based on JIS Z0237 "adhesive tape and adhesive sheet test method", and the peel strength at the time of peeling at a speed of 300 mm/min in the 180℃direction was measured as the adhesive force (N/25 mm) of each adhesive layer. In table 3, the adhesion measured using the adhesive layer of the first stage is referred to as "adhesion after thermal crosslinking", and the adhesion measured using the adhesive layer of the second stage is referred to as "adhesion after photo crosslinking".
Test method of segment difference following property
An adhesive layer (adhesive layer of the first stage) having a thickness of 100 μm crosslinked by a thermal crosslinking agent was transferred from the adhesive sheet a to one side of a polyethylene phthalate resin film having a thickness of 188 μm, and then bonded to the film, to obtain an adhesive film as a sample. Then, a cover glass having a thickness of 1.1mm and having a print level difference of a print layer having a thickness of 42 μm was bonded to the adhesive layer (adhesive layer in the first stage) from above the adhesive layer by a vacuum bonding apparatus under a pressure of 80kPa and a vacuum of-100 kPa. Further, the step following property after the autoclave treatment at a temperature of 60℃and a pressure of 6 atmospheres for 30 minutes was visually confirmed. The visual inspection judgment standard was set as follows, and the evaluation result thereof was recorded as "step following property" in table 3.
O: the following printing level difference and the periphery of the printing level difference have no foaming at all.
Delta: there was a small amount of bubbling around the print level difference.
X: the print level differences are foamed around.
The evaluation results of the adhesive sheets a to B of examples 1 to 5 and the adhesive sheets a to B of comparative examples 1 to 3 are shown in table 3.
TABLE 3
The adhesive sheets B of examples 1 to 5 of the present invention were excellent in wet heat durability because the total light transmittance of the adhesive layer having a thickness of 250 μm after crosslinking by two stages of crosslinking by a thermal crosslinking agent and subsequent crosslinking by a photo crosslinking agent was 90% or more, the "initial haze value" was 1.0% or less, and the "haze value after wet heat" was 4.0% or less, even when the adhesive layer was left in a wet heat environment for a long period of time and then taken out to room temperature environment (temperature 23 ℃.
The adhesive films produced using the adhesive sheets a to B of examples 1 to 5 of the present invention had an adhesive force to soda lime glass of 10N/25mm or less after crosslinking with a thermal crosslinking agent, and 25N/25mm or more after crosslinking by two stages of crosslinking with a thermal crosslinking agent and subsequent crosslinking with a photocrosslinker. Therefore, the adhesive layer crosslinked by the thermal crosslinking agent is excellent in handling performance (easy to peel from an adherend) during the reworking operation, and the adhesive layer crosslinked by the two stages of crosslinking by the thermal crosslinking agent and subsequent crosslinking by the photocrosslinking agent has high adhesive force.
In addition, when an adhesive layer (adhesive layer in the first stage) having a thickness of 100 μm was formed on the adhesive films produced using the adhesive sheets a of examples 1 to 5 of the present invention, the result of the step following property test was to follow a printed step having a thickness of 42 μm, and no bubbling was found around the printed step, and the step following property was excellent.
That is, according to the adhesive sheets a to B of examples 1 to 5 of the present invention and the adhesive film produced using them, an adhesive layer having excellent wet heat durability and good step following property against a step such as frame printing of an adherend and handling property at the time of reworking can be realized as a technical problem of the present invention.
On the other hand, the adhesive layers formed on the adhesive sheets a to B of comparative example 1 were obtained by crosslinking a copolymer obtained by copolymerizing two or more monomers so as to contain the monomer of group (F) but not contain the monomer of group (G), and the adhesive sheet B of comparative example 1 was low in "haze value after wet heat" and high in transparency, and therefore was excellent in wet heat durability. The adhesive film produced using the adhesive sheet a of comparative example 1 had high "adhesion after thermal crosslinking", poor reworkability, foaming around the print level difference, and poor level difference following property.
The adhesive layers formed on the adhesive sheets a to B of comparative example 2 were obtained by copolymerizing two or more kinds of monomers to obtain a copolymer, and crosslinking the copolymer so as to contain no monomer of group (F) but a monomer of group (G), and the adhesive sheet B of comparative example 2 had a high "haze value after wet heat" and low transparency, and thus had poor wet heat durability. In addition, the "adhesion after photocrosslinking" of the adhesive film produced using the adhesive sheet B of comparative example 2 was very low. Further, the adhesive film produced using the adhesive sheet a of comparative example 2 had blisters around the printed step, and the step following property was poor.
The adhesive layers formed on the adhesive sheets a to B of comparative example 3 were obtained by copolymerizing two or more kinds of monomers to obtain a copolymer containing the monomers of the group (F) and the group (G), and the adhesive sheet B of comparative example 3 was excellent in wet heat durability because of low "haze value after wet heat" and high transparency. The adhesive film produced using the adhesive sheet B of comparative example 3 had a slightly lower "adhesion after photocrosslinking". Further, the adhesive film produced using the adhesive sheet a of comparative example 3 had blisters around the printed step, and the step following property was poor.
As described above, the adhesive sheets a to B of comparative examples 1 to 3 and the adhesive film produced using them failed to realize an adhesive layer having excellent wet heat durability and good step following property against a step such as frame printing of an adherend, and handling property at the time of reworking, which are technical problems of the present invention.
In the adhesive sheets B of comparative examples 1 to 3, the "haze value after wet heat" of the adhesive sheets B of comparative examples 1 and 3 obtained by crosslinking the copolymer obtained by copolymerizing two or more monomers so as to contain the monomer of group (F) was low, and the wet heat durability of the adhesive layer was excellent. However, the adhesive sheet B of comparative example 2 obtained by copolymerizing two or more monomers and crosslinking the copolymer so as not to contain the monomer of group (F) has a high "haze value after wet heat" and the adhesive layer has poor wet heat durability. Therefore, it was confirmed that in the adhesive composition for optical use of the present invention, the useful component for obtaining the adhesive layer having excellent wet heat durability is (F) a monomer of (meth) acrylic ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups.

Claims (10)

1. An optical adhesive composition comprising: a copolymer having a weight average molecular weight of 20 to 100 tens of thousands, which is obtained by copolymerizing 2.0 to 10 parts by weight of at least one or more of (B) a nitrogen-containing vinyl monomer or an alkoxy-containing alkyl (meth) acrylate monomer, 1.0 to 10 parts by weight in total of at least one or more of (C) a polyalkylene glycol mono (meth) acrylate monomer, and 0.5 to 10 parts by weight in total of at least one or more of (D) a copolymerizable vinyl monomer having a hydroxyl group, based on 100 parts by weight in total of at least one or more of (A) alkyl (meth) acrylate monomers having a carbon number of an alkyl group of C1 to C18; (F) A monomer of a (meth) acrylic acid ester having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups; (G) A monomer of a (meth) acrylate having an alkylene oxide group in one molecule and having two or more ethylenically unsaturated groups; (E) a thermal crosslinking agent; (H) a photocrosslinking agent,
the optical adhesive composition contains the thermal crosslinking agent (E) in a proportion of 0.01 to 5 parts by weight, the (F) monomer having a (meth) acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups in a proportion of 0.1 to 10 parts by weight, and the (H) photocrosslinker in a proportion of 0.01 to 5 parts by weight, relative to 100 parts by weight of at least one of the (meth) acrylic acid alkyl ester monomers having a carbon number of C1 to C18 in the (A) alkyl group.
2. The adhesive composition for optical use according to claim 1, wherein the adhesive layer having a thickness of 250 μm formed by crosslinking the adhesive composition for optical use by two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent has a total light transmittance of 90% or more and a haze value of 1.0% or less.
3. The optical adhesive composition according to claim 1 or 2, wherein the optical adhesive composition is crosslinked to form an adhesive layer having a thickness of 250 μm by two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent, and the adhesive layer is left for 240 hours at a temperature of 60 ℃ x 90% rh, and then taken out to have a haze value of 4.0% or less in a room temperature environment at a temperature of 23 ℃ x 50% rh.
4. The optical adhesive composition according to claim 1 or 2, wherein the copolymer contains an alkyl (meth) acrylate having an alkyl group with a carbon number of from C8 to C18 in a proportion of 50 parts by weight or more in at least one or more of the alkyl (meth) acrylate monomers having a carbon number of from C1 to C18 in a total of 100 parts by weight of (a) the alkyl groups.
5. The optical adhesive composition according to claim 1 or 2, wherein the comonomer of the copolymer comprises (C) a polyalkylene glycol mono (meth) acrylate monomer, the optical adhesive composition comprising (G) a monomer of a (meth) acrylate having an alkylene oxide group in one molecule and having two or more ethylenically unsaturated groups, and the average number of repetitions of the alkylene oxide of (C) and (G) is 4 to 14.
6. An adhesive film comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the adhesive layer is formed by crosslinking the adhesive composition for optical use according to any one of claims 1 to 5 with the (E) thermal crosslinking agent or by crosslinking the adhesive composition for optical use according to any one of claims 1 to 5 with the (E) thermal crosslinking agent and subsequent crosslinking with the (H) photo crosslinking agent,
the adhesive layer crosslinked by the (E) thermal crosslinking agent has an adhesive force to soda-lime glass of 10N/25mm or less, and the adhesive layer crosslinked by the (E) thermal crosslinking agent and the subsequent crosslinking by the (H) photo crosslinking agent has an adhesive force to soda-lime glass of 25N/25mm or more.
7. An adhesive film comprising an adhesive layer laminated on one surface of a polyethylene phthalate resin film having a thickness of 188 μm, wherein the adhesive layer is formed by using the adhesive composition for optical use according to any one of claims 1 to 5 and crosslinking the adhesive layer with the thermal crosslinking agent (E), and wherein when the adhesive film is bonded to a glass having a print level difference having a print layer having a thickness of 42 μm via the adhesive layer having a thickness of 100 μm, the adhesive layer has good following property against the print level difference and no foaming is caused around the print level difference.
8. A film for a touch panel using the adhesive film according to claim 6 or 7.
9. An adhesive sheet comprising an adhesive layer formed by laminating the adhesive composition for optical use according to any one of claims 1 to 5 and crosslinked by the thermal crosslinking agent (E) between two release films subjected to release treatment.
10. An optical film with an adhesive layer formed by laminating an adhesive layer on at least one side of an optical film, the adhesive layer being formed by using the adhesive composition for optical use according to any one of claims 1 to 5 and crosslinking with the (E) thermal crosslinking agent, or by using the adhesive composition for optical use according to any one of claims 1 to 5 and crosslinking in two stages of crosslinking with the (E) thermal crosslinking agent and subsequent crosslinking with the (H) photo crosslinking agent.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103153610A (en) * 2010-09-29 2013-06-12 日东电工株式会社 Resin film with adhesive layer, laminated film, and touchpanel
CN106047230A (en) * 2015-04-15 2016-10-26 藤森工业株式会社 Adhesive layer and adhesive film
JP2022085858A (en) * 2020-11-27 2022-06-08 三洋化成工業株式会社 Photocurable adhesive composition and adhesive film

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4072927B2 (en) * 1997-08-28 2008-04-09 リンテック株式会社 Energy ray-curable hydrophilic pressure-sensitive adhesive composition and use thereof
CN102365260B (en) * 2009-03-31 2015-04-15 株式会社日本触媒 a-(unsaturated alkoxyalkyl)acrylate composition and process for production thereof
JP5725760B2 (en) 2010-08-19 2015-05-27 大同化成工業株式会社 Acrylic polymer compounds used in pressure-sensitive adhesive compositions for touch panels
JP5790089B2 (en) 2011-03-31 2015-10-07 Dic株式会社 Double-sided adhesive tape
JP5642028B2 (en) * 2011-07-06 2014-12-17 株式会社日本触媒 Optical UV-curable resin composition, cured product, and display device
JP2013256552A (en) 2012-06-11 2013-12-26 Soken Chem & Eng Co Ltd Photopolymerizable adhesive, adhesive sheet, and laminate for touch panel
JP6026260B2 (en) * 2012-12-17 2016-11-16 藤森工業株式会社 Adhesive layer and adhesive film
JP6384988B2 (en) 2014-05-23 2018-09-05 藤森工業株式会社 Surface protective film with decorative printing layer, anti-scattering film, touch panel and electronic device
JP6363930B2 (en) * 2014-10-10 2018-07-25 日東電工株式会社 Optical film with adhesive, method for producing the same, and method for producing an image display device
JP6228146B2 (en) * 2015-01-09 2017-11-08 藤森工業株式会社 Adhesive composition and adhesive film
JP6904926B2 (en) * 2015-04-15 2021-07-21 藤森工業株式会社 Adhesive layer and adhesive film

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103153610A (en) * 2010-09-29 2013-06-12 日东电工株式会社 Resin film with adhesive layer, laminated film, and touchpanel
CN106047230A (en) * 2015-04-15 2016-10-26 藤森工业株式会社 Adhesive layer and adhesive film
JP2022085858A (en) * 2020-11-27 2022-06-08 三洋化成工業株式会社 Photocurable adhesive composition and adhesive film

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