CN111465668B - Release film-attached pressure-sensitive adhesive sheet and method for producing same - Google Patents

Release film-attached pressure-sensitive adhesive sheet and method for producing same Download PDF

Info

Publication number
CN111465668B
CN111465668B CN201880076662.3A CN201880076662A CN111465668B CN 111465668 B CN111465668 B CN 111465668B CN 201880076662 A CN201880076662 A CN 201880076662A CN 111465668 B CN111465668 B CN 111465668B
Authority
CN
China
Prior art keywords
adhesive sheet
release film
release
photocurable
layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201880076662.3A
Other languages
Chinese (zh)
Other versions
CN111465668A (en
Inventor
松本真理
形见普史
三井数马
野中崇弘
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nitto Denko Corp
Original Assignee
Nitto Denko Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nitto Denko Corp filed Critical Nitto Denko Corp
Publication of CN111465668A publication Critical patent/CN111465668A/en
Application granted granted Critical
Publication of CN111465668B publication Critical patent/CN111465668B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
    • C08K5/3477—Six-membered rings
    • C08K5/3492—Triazines
    • 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
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • 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
    • 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
    • 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
    • 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]
    • 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
    • C09J7/40—Adhesives in the form of films or foils characterised by release liners
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
    • C09J2301/416—Additional features of adhesives in the form of films or foils characterized by the presence of essential components use of irradiation

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Laminated Bodies (AREA)

Abstract

The invention provides a release film-equipped adhesive sheet (1) comprising: a photocurable pressure-sensitive adhesive sheet (50) having a first main surface and a second main surface, and a first release film (10) temporarily attached to the first main surface of the pressure-sensitive adhesive sheet, wherein the first release film comprises a release layer (15) on a film base (11), the release layer (15) is in contact with the pressure-sensitive adhesive sheet (50), the pressure-sensitive adhesive sheet (50) contains a photocurable acrylic polymer and an ultraviolet absorber, the release layer (15) is a silicone-based release layer, and the content of Si atoms is 0.02 to 0.07g/m2。

Description

Release film-attached pressure-sensitive adhesive sheet and method for producing same
Technical Field
The present invention relates to an adhesive sheet to which a release film is temporarily attached, and a method for producing the same.
Background
A transparent adhesive sheet is used when an optical member is bonded to a display device such as a liquid crystal display and an organic EL display, or to an input device for a display such as a touch panel. The transparent adhesive sheet is generally provided in the form of a release film-equipped adhesive sheet having release films attached to both sides thereof. When using the pressure-sensitive adhesive sheet, first, one release film (light release film) is peeled off to expose one surface of the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet is bonded to a first adherend, and the other release film (heavy release film) is peeled off to bond a second adherend to the other surface of the pressure-sensitive adhesive sheet.
From the viewpoint of suppressing deterioration of elements due to ultraviolet rays, ultraviolet blocking properties are sometimes required for optical members used in display devices, input devices, and the like. For example, in an organic EL display, deterioration of organic molecules constituting a light-emitting layer and the like by ultraviolet rays greatly affects display characteristics, and thus high ultraviolet blocking properties are required for an optical member disposed on the front surface of an element. In addition, in a polarizing plate used in a liquid crystal display or an organic EL display, in order to prevent deterioration of a polarizer due to ultraviolet rays (for example, discoloration of iodine), an optical member disposed on the front surface of the polarizer is required to have ultraviolet blocking properties.
As a method for imparting ultraviolet barrier properties to an adhesive sheet, a method of adding an ultraviolet absorber to an adhesive composition is known. For example, patent document 1 describes: an adhesive composition obtained by adding an ultraviolet absorber to a thermal polymerization type acrylic adhesive solution was applied in a film form, and then heated and dried to obtain an adhesive sheet having ultraviolet barrier properties. Patent document 2 describes: a photocurable acrylic pressure-sensitive adhesive composition containing a photocurable acrylic composition, a photopolymerization initiator and an ultraviolet absorber was applied in a layer form to a release film substrate, and then another release film was laminated thereon to block contact with air, and in this state, photocuring was performed to obtain a photocurable pressure-sensitive adhesive sheet having ultraviolet blocking properties.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2013-75978
Patent document 2: japanese patent laid-open publication No. 2016-155981
Disclosure of Invention
Problems to be solved by the invention
If a photocurable adhesive is used as described in patent document 2, a solvent is not required for forming the adhesive sheet, and therefore, the thickness of the adhesive sheet is easily increased. In addition, the following advantages are provided: the smoothness of the adhesive sheet can be improved by photocuring the release sheet in a state where the release sheet is in contact with both surfaces of the sheet-like photocurable adhesive composition.
However, according to the studies of the present inventors, it has been found that if a photocurable adhesive composition containing an ultraviolet absorber is irradiated with ultraviolet rays through a release film to perform photocuring, the peeling force between the release film on the light-irradiated surface and the photocurable adhesive sheet is greatly increased, and when the composition is adhered to an adherend, the release film may be difficult to peel. In view of the above problems, an object of the present invention is to provide a release film-attached pressure-sensitive adhesive sheet having ultraviolet blocking properties and good releasability from a release film.
Means for solving the problems
The pressure-sensitive adhesive sheet with a release film of the present invention comprises: the pressure-sensitive adhesive sheet includes a photocurable pressure-sensitive adhesive sheet having a first main surface and a second main surface, and a first release film temporarily attached to the first main surface of the pressure-sensitive adhesive sheet. The first release film includes a release layer on a film base, the release layer being in contact with an adhesive sheet, and the adhesive sheet includes a photocurable acrylic polymer and an ultraviolet absorber. The release film-equipped adhesive sheet may further include a second release film temporarily attached to the second main surface of the adhesive sheet.
The first main surface of the adhesive sheet is a light irradiation surface when the photocurable adhesive composition is photocured. That is, the photocurable adhesive composition is irradiated with light through the first release film to form a photocurable adhesive sheet. By using a release film having a predetermined silicone-based release layer as the first release film provided on the light irradiation surface side of the photocurable adhesive composition, an excessive increase in the release force can be suppressed even when the adhesive contains an ultraviolet absorber. The Si atom content of the silicone-based release layer of the first release film is preferably 0.02 to 0.07g/m2。
The pressure-sensitive adhesive sheet preferably has a light transmittance of 10% or less at a wavelength of 380 nm. The adhesive sheet preferably contains 0.1 to 10 parts by weight of an ultraviolet absorber per 100 parts by weight of the acrylic polymer. As the ultraviolet absorber, for example, a triazine-based ultraviolet absorber is used. The acrylic polymer of the pressure-sensitive adhesive sheet may contain, as a monomer component, a polyfunctional monomer component having 2 or more polymerizable functional groups in 1 molecule.
In a state where the first release film is attached to the first main surface of the photocurable adhesive composition layer, the photocurable adhesive composition is irradiated with light through the first release film, whereby a release film-attached adhesive sheet can be obtained. The photocurable adhesive composition comprises an acrylic material, an ultraviolet absorber, and a photopolymerization initiator. Examples of the acrylic material contained in the photocurable adhesive composition include an acrylic monomer and a partial polymer thereof. The acrylic material may contain both an acrylic monomer and a partial polymer of the acrylic monomer.
In one embodiment, a laminate having a photocurable adhesive composition layer sandwiched between a first release film and a second release film is irradiated with light from the first release film side to photocure the photocurable adhesive composition, thereby obtaining an adhesive sheet having release films temporarily attached to both surfaces. In the case of an adhesive sheet temporarily attached with release films on both sides, the peeling force between the first release film and the adhesive sheet may be larger than the peeling force between the second release film and the adhesive sheet.
ADVANTAGEOUS EFFECTS OF INVENTION
The pressure-sensitive adhesive sheet having high visible light transmittance and ultraviolet blocking property can be suitably used as an optical pressure-sensitive adhesive sheet for display devices and input devices for displays, which require ultraviolet blocking property. The release film-equipped adhesive sheet of the present invention can suppress an excessive increase in the peeling force between the adhesive sheet and the first release film, and therefore has excellent workability in peeling the release film from the adhesive sheet and in bonding the adhesive sheet to an adherend.
Drawings
Fig. 1 is a sectional view showing a laminated structure of a release film-attached adhesive sheet.
Description of the symbols
1: adhesive sheet with release film
50: adhesive sheet
10. 20: mold release film
11. 21: base material
15. 25: release layer
5: laminated body
55: photocurable adhesive composition layer
Detailed Description
The pressure-sensitive adhesive sheet with a release film of the present invention includes a release film temporarily attached to at least one surface of the pressure-sensitive adhesive sheet. The term "temporarily attached" means a state of being releasably attached. The release film-attached pressure-sensitive adhesive sheet may have release films temporarily attached to both surfaces of the pressure-sensitive adhesive sheet.
Fig. 1 is a sectional view of a release film-equipped pressure-sensitive adhesive sheet 1 having release films 10 and 20 temporarily adhered to both surfaces of a pressure-sensitive adhesive sheet 50. The adhesive sheet 50 is formed by forming an adhesive into a sheet shape. The adhesive sheet 50 is transparent and has low light absorption of visible light. The total light transmittance of the pressure-sensitive adhesive sheet 50 is preferably 85% or more, more preferably 90% or more. The haze of the adhesive sheet is preferably 2% or less, more preferably 1% or less. The total light transmittance and haze were measured by a haze meter according to JIS K7136.
The pressure-sensitive adhesive sheet 50 is an acrylic pressure-sensitive adhesive containing a photocurable acrylic polymer, and contains an ultraviolet absorber in addition to the acrylic polymer. The acrylic pressure-sensitive adhesive sheet is formed of a photocurable pressure-sensitive adhesive obtained by applying a photocurable pressure-sensitive adhesive composition containing a partial polymer (prepolymer) of an acrylic monomer and/or an acrylic polymer, an ultraviolet absorber, and a photopolymerization initiator in layers and photocuring the layers. In the present specification, the term "photocurable" adhesive refers to an adhesive that contains a compound having a photopolymerizable functional group such as a vinyl group or a (meth) acryloyl group and is photocurable, and the term "photocurable" adhesive refers to an adhesive obtained by photocuring a photocurable adhesive. In the case where a part of the photopolymerizable compound remains unreacted in the adhesive after polymerization of the photocurable adhesive, the adhesive may be photocurable (photocurable) or photocurable.
[ Photocurable adhesive composition ]
The photocurable adhesive composition comprises a photopolymerizable acrylic material, an ultraviolet absorber, and a photopolymerization initiator.
< photopolymerizable acrylic material >
Examples of the photopolymerizable acrylic material contained in the photocurable adhesive composition include acrylic monomers and partial polymers (prepolymers) thereof.
(monomer component)
As the acrylic monomer, an alkyl (meth) acrylate having an alkyl group of 1 to 20 carbon atoms, wherein the alkyl group of the alkyl (meth) acrylate may have a branch, can be suitably used. The content of the alkyl (meth) acrylate is preferably 40% by weight or more, more preferably 50% by weight or more, and further preferably 60% by weight or more, based on the total amount of the monomer components of the acrylic material.
The monomer component may contain a high-polarity monomer such as a hydroxyl group-containing monomer and a nitrogen-containing monomer in addition to the alkyl (meth) acrylate. When the acrylic polymer contains a highly polar monomer unit, the cohesive strength of the adhesive agent can be improved, the adhesion of the adhesive sheet to an adherend can be improved, and the clouding of the adhesive agent in a high-temperature and high-humidity environment can be suppressed, which tends to improve the transparency of the adhesive sheet.
As the hydroxyl group-containing monomer, there may be mentioned: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxydodecyl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl acrylate. The content of the hydroxyl group-containing monomer is preferably 1 to 40 wt%, more preferably 3 to 30 wt%, and further preferably 5 to 20 wt% with respect to the total amount of the monomer components.
Examples of the nitrogen-containing monomer include: n-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridinePyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl pyrazine
Figure BDA0002510840770000051
Vinyl monomers such as oxazole, vinyl morpholine, (meth) acryloyl morpholine, N-vinylcarboxylic acid amides and N-vinylcaprolactam, and cyanoacrylate monomers such as acrylonitrile and methacrylonitrile. The nitrogen-containing monomer preferably has a cyclic structure containing a nitrogen atom, and among these, lactam-based vinyl monomers such as N-vinylpyrrolidone are preferred. The content of the nitrogen-containing monomer is preferably 0.5 to 50% by weight, more preferably 1 to 40% by weight, and further preferably 3 to 30% by weight, based on the total amount of the monomer components.
The monomer component may contain monomers other than the above monomers, such as a carboxyl group-containing monomer, a cyclic ether group-containing monomer, and a silane-based monomer.
The monomer component may contain a polyfunctional polymerizable compound having 2 or more polymerizable functional groups in 1 molecule. Examples of the polyfunctional polymerizable compound include compounds having 2 or more C ═ C bonds in 1 molecule, compounds having 1C ═ C bond and epoxy, aziridine, and the like,
Figure BDA0002510840770000052
And compounds having a polymerizable functional group such as oxazoline, hydrazine, or methylol group. Among them, a polyfunctional polymerizable compound having 2 or more C ═ C bonds in 1 molecule is preferable. The polyfunctional polymerizable compound may be present in the adhesive composition in the form of a monomer or an oligomer, or may be bonded to a functional group such as a hydroxyl group of the prepolymer component.
Examples of the polyfunctional polymerizable compound having 2 or more C ═ C bonds in 1 molecule include: ester compounds of polyfunctional acrylates (polyhydric alcohols and (meth) acrylic acids) such as (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 2-ethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and tetramethylolmethane tri (meth) acrylate; allyl (meth) acrylate, vinyl (meth) acrylate, diethenylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di (meth) acrylate, hexyl di (meth) acrylate, and the like. Of these, polyfunctional acrylates, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like are preferably used as the polyfunctional monomer.
The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, and the like, and is preferably 5% by weight or less, more preferably 3% by weight or less, and still more preferably 2% by weight or less, based on the total amount of the monomer components. The polyfunctional monomer may be used in an amount of 0.001 parts by weight or more, 0.01 parts by weight or more, or 0.05 parts by weight or more, relative to the total amount of the monomer components.
In the photocurable adhesive composition, the above-mentioned monomer component may be present in the form of a partial polymer (prepolymer). The prepolymer is a polymer obtained by partially polymerizing a monomer component. By allowing the monomer component to be present in the form of a prepolymer, the viscosity of the photocurable adhesive composition can be adjusted to a range suitable for application to a support substrate.
The prepolymer can be prepared, for example, by partially polymerizing a prepolymer-forming composition obtained by mixing a monomer component with a polymerization initiator. The prepolymer-forming composition may contain all of the monomer components constituting the acrylic polymer, or may contain only a part of the monomers constituting the acrylic polymer. When the monomer component constituting the acrylic polymer contains a monofunctional monomer and a polyfunctional monomer, the polyfunctional monomer may be added to a prepolymer composition obtained by partially polymerizing only the monofunctional monomer to prepare an adhesive composition. By adding a polyfunctional monomer to a prepolymer composition obtained by partially polymerizing only a monofunctional monomer and then polymerizing the resultant mixture, crosslinking points formed by the polyfunctional monomer can be uniformly introduced into the polymer. The composition for forming a prepolymer may contain a part of the polyfunctional monomer component constituting the acrylic polymer, and the prepolymer may be polymerized and then the remaining part of the polyfunctional monomer component may be added to the composition for forming a prepolymer to perform post-polymerization.
The prepolymer may be prepared by polymerization in 2 or more stages or 3 or more stages. For example, after only a monofunctional monomer is preliminarily polymerized, a polyfunctional monomer is added to partially polymerize the monomer to prepare a prepolymer composition, and if necessary, a monomer component or the like is further added to perform post-polymerization.
The method of polymerizing the prepolymer is not particularly limited, and photopolymerization by irradiation with active light such as ultraviolet light is preferable from the viewpoint of adjusting the reaction time and setting the molecular weight (polymerization rate) of the prepolymer in a desired range. When photopolymerization is performed, the prepolymer composition preferably contains a photopolymerization initiator, and specific examples of the photopolymerization initiator will be described later.
The prepolymer-forming composition may contain a chain transfer agent and the like as necessary in addition to the monomer component and the polymerization initiator. The chain transfer agent has a function of stopping elongation of the polymer by receiving a radical from a growing polymer chain, and starting polymerization again by attacking the monomer by the chain transfer agent having received the radical. By using the chain transfer agent, the excessive increase in the molecular weight is suppressed without lowering the radical concentration in the reaction system. As the chain transfer agent, thiols such as α -thioglycerol, dodecylmercaptan, glycidylthiol, mercaptoacetic acid, 2-mercaptoethanol, mercaptoglycolic acid, 2-ethylhexyl thioglycolate, and 2, 3-dimercapto-1-propanol are suitably used.
The polymerization rate of the prepolymer is not particularly limited, but is preferably 3 to 50%, more preferably 5 to 40%, from the viewpoint of achieving a viscosity suitable for coating on a substrate. The polymerization ratio of the prepolymer can be adjusted to a desired range by adjusting the kind and amount of the photopolymerization initiator, the irradiation intensity and irradiation time of the active light such as ultraviolet light, and the like. The polymerization ratio was calculated from the weight of the prepolymer composition before and after heating (drying) at 130 ℃ for 3 hours according to the following formula. When partial polymerization is performed by solution polymerization, the polymerization rate is calculated by subtracting the amount of the solvent from the total weight of the prepolymer composition as the weight before heating in the following formula.
Polymerization rate (%) of polymer was 100 × (weight after heating/weight before heating)
< preparation of Photocurable adhesive composition >
The photocurable adhesive composition is obtained by mixing the remaining monomer components, an ultraviolet absorber, a photopolymerization initiator, and other additives with the above photopolymerizable acrylic material (monomer and/or its partial polymer).
< ultraviolet absorber >
Examples of the ultraviolet absorber include: benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, triazine ultraviolet absorbers, salicylate ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, and the like. Triazine-based ultraviolet absorbers are preferred because they have high ultraviolet absorptivity, excellent compatibility with acrylic polymers, and high transparency, and among them, triazine-based ultraviolet absorbers containing a hydroxyl group are preferred, and particularly hydroxyphenyl triazine-based ultraviolet absorbers are preferred. The number of hydroxyl groups of the triazine-based ultraviolet absorber is preferably 2 or less.
As the ultraviolet absorber, commercially available ones can be used. Commercially available triazine ultraviolet absorbers include: a reaction product of 2- (4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazin-2-yl) -5-hydroxyphenyl with [ (alkoxy) methyl ] ethylene oxide (manufactured by BASF as "TINUVIN 400"), a reaction product of 2- (2, 4-dihydroxybenzene) -4, 6-bis- (2, 4-dimethylphenyl) -1,3, 5-triazine with 2-ethylhexyl epoxypropionate (manufactured by BASF as "TINUVIN 405"), (2, 4-bis [ 2-hydroxy-4-butoxyphenyl ] -6- (2, 4-dibutoxyphenyl) -1,3, 5-triazine (manufactured by BASF as "TINUVIN 460"), 2- (4, 6-Diphenyl-1, 3, 5-triazin-2-yl) -5- [ (hexyl) oxy ] phenol ("TINUVIN 577" from BASF), 2- (2-hydroxy-4- [ 1-octyloxycarbonylethoxy ] phenyl) -4, 6-bis (4-phenylphenyl) -1,3, 5-triazine ("TINUVIN 479" from BASF), and the like.
The content of the ultraviolet absorber in the photocurable adhesive composition is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 7 parts by weight, and still more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the monomer component. By setting the content of the ultraviolet absorber to the above range, it is possible to suppress a decrease in transparency due to bleeding of the ultraviolet absorber or the like, and to improve the ultraviolet barrier property of the adhesive sheet. When the content of the ultraviolet absorber is within the above range, the polymerization rate of the adhesive composition can be inhibited from decreasing.
< photopolymerization initiator >
The photocurable adhesive composition contains a photopolymerization initiator. The photopolymerization initiator is a photo radical generator that generates radicals by visible light or ultraviolet light having a wavelength shorter than 450 nm.
When the photocurable adhesive composition contains an ultraviolet absorber, part of irradiation light for photocuring is absorbed by the ultraviolet absorber. From the viewpoint of promoting the generation of radicals by cleavage of the photopolymerization initiator and increasing the polymerization rate, it is preferable to use a photopolymerization initiator having sensitivity in a wavelength region where absorption by an ultraviolet absorber is small. Specifically, the photopolymerization initiator preferably has sensitivity at a wavelength longer than 380nm, more preferably at a wavelength longer than 400 nm. Preferably, the absorption coefficient at a wavelength of 405nm is 1X 102[mLg-1cm-1]The photopolymerization initiator described above. The photopolymerization initiator having a photosensitivity of a long wavelength may have a sensitivity to light having a wavelength of 400nm or less.
Specific examples of the photopolymerization initiator having a photosensitivity of a wavelength of 400nm or more include: acylphosphine oxides such as 2,4, 6-trimethylbenzoyldiphenylphosphine oxide ("Lucirin TPO" manufactured by BASF) and 2,4, 6-trimethylbenzoylphenylethoxyphosphine oxide ("Lucirin TPO-L" manufactured by BASF); aminoketones such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 ("Irgacure 369" manufactured by BASF); bisacylphosphine oxides such as bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide ("Irgacure 819" from BASF), 2-dimethoxy-1, 2-diphenylethan-1-one ("Irgacure 651" from BASF), bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide ("CGI 403" from BASF), and the like.
As the photopolymerization initiator, a photopolymerization initiator having a photosensitivity of a long wavelength and a photopolymerization initiator having no photosensitivity of a long wavelength (for example, the number of light absorption coefficients at a wavelength of 405nm is less than 1X 10)2[mLg-1cm-1]The photopolymerization initiator).
Examples of the photopolymerization initiator having no photosensitivity with a long wavelength include: benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, alpha-alcohol ketone photopolymerization initiator, photoactive oxime photopolymerization initiator, benzoin photopolymerization initiator, benzil photopolymerization initiator, benzophenone photopolymerization initiator, ketal photopolymerization initiator, thioxanthone photopolymerization initiator, acyl phosphine oxide photopolymerization initiator, cyclopentadienyl titanium photopolymerization initiator, and the like.
The content of the photopolymerization initiator in the photocurable adhesive composition is preferably 0.02 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the total of the monomer component and the prepolymer component constituting the acrylic polymer. When the photopolymerization initiator is too small, the polymerization rate may be insufficient, and when the photopolymerization initiator is too large, the molecular weight of the polymer may be low, and the adhesive strength of the adhesive may be insufficient.
As described above, in the preparation (partial polymerization) of the prepolymer, a photopolymerization initiator may also be used. The photopolymerization initiator used for the partial polymerization may be the same as or different from the photopolymerization initiator added to the photocurable adhesive composition. When the prepolymer-forming composition does not contain an ultraviolet absorber and an ultraviolet absorber is added after partial polymerization, the photopolymerization initiator used for partial polymerization may not have a light sensitivity of a long wavelength. The unreacted material of the photopolymerization initiator used in the partial polymerization may be used as it is as the photopolymerization initiator in the photopolymerizable adhesive composition.
From the viewpoint of the utilization efficiency of the irradiated light, it is preferable that the ultraviolet absorber is not contained in the prepolymer composition and is added to the prepolymer composition after the partial polymerization. For example, it is preferable to use a photopolymerization initiator having no long-wavelength photosensitivity as an initial addition polymerization initiator to perform partial polymerization, add an ultraviolet absorber and a photopolymerization initiator having long-wavelength photosensitivity as an additional polymerization initiator to the partially polymerized composition to prepare a photocurable adhesive composition, coat the photocurable adhesive composition in a layer form on a substrate, and perform post polymerization.
< other ingredients >
The photocurable adhesive composition may contain a chain transfer agent. The chain transfer agent contained in the photocurable adhesive composition is not particularly limited, and for example, the above-mentioned chain transfer agent can be used. For the purpose of adjusting the adhesive strength, etc., a silane coupling agent, a crosslinking agent, a tackifier, a plasticizer, a softening agent, etc. may be contained in the adhesive composition. The adhesive composition may contain additives such as a deterioration preventing agent, a filler, a colorant, an antioxidant, a surfactant, and an antistatic agent, within a range not to impair the characteristics of the adhesive.
The photocurable adhesive composition preferably has a viscosity (e.g., about 5 to 100 poise) suitable for application to a substrate. The viscosity of the pressure-sensitive adhesive composition can be adjusted by, for example, adding various polymers such as a tackifier, a polyfunctional monomer, and the like, and the polymerization rate of a prepolymer. In the photocurable adhesive composition, the content of the acrylic monomer component (acrylic monomer and partial polymer of acrylic monomer) is 50% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more.
[ formation of adhesive sheet ]
The photocurable adhesive composition is applied to a support substrate and photocured to obtain an adhesive sheet. Examples of the method for coating the adhesive composition on the substrate include roll coating, roll-lick coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, blade coating, air knife coating, curtain coating, lip coating, and die coating. Since oxygen in the air inhibits photo radical polymerization, it is preferable to provide a cover sheet on the coating layer of the photocurable adhesive composition to block oxygen. The adhesive composition may be applied so that the photocurable adhesive composition is sandwiched between 2 sheets (a support base and a cover sheet).
The thickness of the photocurable adhesive composition (thickness of the adhesive sheet 50) to be applied is not particularly limited, and is, for example, about 10 to 500 μm. From the viewpoint of improving the ultraviolet absorptivity by the pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet is preferably 50 μm or more, more preferably 100 μm or more, and still more preferably 150 μm or more. The light transmittance of the adhesive sheet 50 at a wavelength of 380nm is preferably 10% or less, more preferably 5% or less, and still more preferably 3% or less.
A laminate having a photocurable acrylic pressure-sensitive adhesive composition layer on a support substrate is irradiated with ultraviolet light and/or short-wavelength visible light to be photocured, thereby obtaining a pressure-sensitive adhesive sheet. In the case where the laminate in which the photocurable adhesive composition layer is sandwiched between the support base material and the cover sheet is subjected to light irradiation for photocuring, the light irradiation may be performed from either the support base material side or the cover sheet side, or may be performed from both sides. As described in detail later, in the present invention, as the support base material or the cover sheet attached to the light irradiation surface side of the adhesive sheet, the release film 10 having the predetermined release layer 15 can be used.
From the viewpoint of improving the curing rate, the light irradiation intensity is preferably 5mW/cm2The above. From the viewpoint of sufficiently increasing the molecular weight of the acrylic polymer after photocuring and ensuring the retention at high temperature, the light irradiation intensity is preferably 20mW/cm2The following components,
The cumulative light quantity of the irradiation light is preferably 100 to 5000mJ/cm2Left and right. The light source used for the light irradiation is not particularly limited as long as it can irradiate light in the wavelength range of the sensitivity of the photopolymerization initiator contained in the adhesive composition, and an LED light source, a high-pressure mercury lamp, a fluorescent lamp, and the like are preferably used,An ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like.
Most of the ultraviolet light irradiated to the photocurable adhesive composition containing an ultraviolet absorber is absorbed by the ultraviolet absorber. From the viewpoint of suppressing the decrease in molecular weight due to the increase in temperature and improving the utilization efficiency of the irradiation light and the curing speed, it is preferable to irradiate the light in a wavelength region where the light absorption by the ultraviolet absorber is small. Since the heat emission from the light source is small and light having a small wavelength range can be irradiated, an LED light source is preferably used. When an LED light source is used, the emission peak wavelength is preferably 350nm or more, more preferably 380nm or more, and further preferably 400nm or more.
The final polymerization rate of the monomer component in the pressure-sensitive adhesive sheet after photocuring is preferably 90% or more, more preferably 95% or more, and further preferably 98% or more. The gel fraction of the pressure-sensitive adhesive sheet is preferably 50% or more, more preferably 75% or more, and still more preferably 85% or more.
[ Release film ]
As the supporting base for applying the adhesive composition and the cover sheet attached to the surface of the coating layer of the adhesive composition, a release film having a release layer on the surface in contact with the coating layer (adhesive sheet) is preferably used. In the present invention, photocuring is performed in a state where the release film (first release film) 11 having the predetermined silicone-based release layer 15 is provided on the light irradiation surface side of the photocurable adhesive composition layer 55.
< substrate >
Various transparent resin films are used as the substrates 11 and 21 of the release films 10 and 20. As the resin material, there can be mentioned: polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, polyphenylene sulfide resins, and the like. Among these, polyester resins such as polyethylene terephthalate are particularly preferable. The thickness of the substrates 11, 21 is preferably 10 to 200 μm, more preferably 25 to 150 μm.
< Release layer >
As the material of the release layer, there can be mentioned: silicone release agents, fluorine release agents, long-chain alkyl release agents, fatty acid amide release agents, silica powders, and the like. Since both adhesiveness and releasability to an acrylic pressure-sensitive adhesive sheet can be achieved, a release film having a silicone-based release layer 25 formed of a silicone-based release agent on the surface of a film base 21 is preferably used as the release film 20.
The release film 10 attached to the light irradiation surface side of the photocurable adhesive composition layer 55 includes a silicone release layer 15. The silicone release layer 15 has a Si atom content per unit area of 0.02 to 0.07g/m2. The Si atom content of the silicone-based release layer 15 is preferably 0.025 to 0.06g/m2More preferably 0.03 to 0.055g/m2。
The silicone-based release layer 15 of the release film 10 contains a curable silicone resin. The silicone resin may be of the type having itself as a main component, or may be a silicone-modified resin obtained by introducing a reactive silicone into an organic resin such as a urethane resin, an epoxy resin, or an alkyd resin by graft polymerization or the like. As the silicone resin, various curing reaction types such as addition type, condensation type, ultraviolet curing type, electron beam curing type, and solvent-free type can be used. In particular, a silicone resin of a type that forms a releasable film by curing through an addition reaction by heat is preferably used because it has excellent adhesion to a film base and can achieve both adequate adhesion to an acrylic adhesive sheet and releasability.
Examples of the silicone-based material that cures by an addition reaction include polyorganosiloxanes having a vinyl group or an alkenyl group in the molecule. Examples of the alkenyl group include a 3-butenyl group, a 4-pentenyl group, a 5-hexenyl group, a 6-heptenyl group, a 7-octenyl group, an 8-nonenyl group, a 9-decenyl group, a 10-undecenyl group, and a 11-dodecenyl group. Examples of the polyorganosiloxane include polyalkylalkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane; a polyalkylaryl siloxane; and poly (dimethylsiloxane-diethylsiloxane) and the like, which are copolymers using a plurality of monomer components containing Si atoms.
As the silicone resin, a commercially available composition containing a curable silicone resin can be used. Commercially available products as curable silicone release agents include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2422 and X-62-2461, all of which are manufactured by shin-Etsu chemical industries; YSR-3022, TPR-6700, TPR-6720, and TPR-6721 made of Toshiba organosilica; LTC300B, LTC303E, LTC310, LTC314, SRX357, BY24-749, SD7333, BY24-179, BY24-840, BY24-842, BY24-850, SP7015, SP7259, SD7220, SD7226, and SD7229 manufactured BY Toray Dow Corning; DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210 and the like manufactured by Dow Corning Asia.
The curable silicone-based release agent composition may further contain an additive (release controlling agent) for the purpose of, for example, adjusting the releasability of the release layer. The addition type silicone type release agent composition may contain a curing catalyst. As the curing catalyst, a platinum-based catalyst is preferable. Examples of the platinum-based catalyst include chloroplatinic acid, an olefin complex of platinum, and an olefin complex of chloroplatinic acid. The amount of the platinum catalyst used is about 10 to 1000ppm in terms of platinum relative to the total solid content of the silicone release agent composition.
The silicone-based mold release composition may contain an organic solvent. As the organic solvent, there may be mentioned: hydrocarbon solvents such as cyclohexane, n-hexane, and n-heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone; alcohol solvents such as methanol, ethanol, and butanol. The organic solvent may be a mixed solvent. The amount of the organic solvent used is preferably about 80 to 99.9 mass% in the silicone-based release agent composition.
The silicone-based mold release composition may contain various additives such as a filler, an antistatic agent, an antioxidant, a plasticizer, and a colorant, as required.
The silicone-based release layer is formed by applying the silicone-based release agent composition onto the substrate 11 and heating and drying the composition. Examples of the coating method include a roll coating method, a roll lick coating method, a gravure coating method, a reverse coating method, a roll brush method, a spray coating method, a dip roll coating method, a bar coating method, a blade coating method, an air knife coating method, a shower coating method, a die lip coating method, and a die coating method. As the heating drying method, hot air drying is exemplified. The conditions for hot air drying are different depending on the heat resistance of the base material, and are usually about 80 to 150 ℃ and about 10 seconds to 10 minutes. If necessary, for the purpose of accelerating the addition reaction of the silicone, a combination of heat treatment and irradiation with active energy rays such as ultraviolet irradiation may be used.
The amount of the silicone release agent composition applied is 0.03 to 1g/m based on the amount of the silicone resin2The left and right modes can be adjusted. The thickness of the silicone-based release layer 15 is, for example, 10 to 500 nm. The amount of the silicone-based mold releasing agent composition to be applied and the thickness of the silicone-based mold releasing layer 15 may be adjusted so that the Si atom content of the silicone-based mold releasing layer 15 falls within the above-described range.
[ releasability between release film and adhesive sheet ]
In a release film-equipped pressure-sensitive adhesive sheet having release films temporarily adhered to both surfaces of the pressure-sensitive adhesive sheet, the peel force between the pressure-sensitive adhesive sheet and one release film is generally relatively smaller than the peel force between the pressure-sensitive adhesive sheet and the other release film. When the adhesive sheet is used, a release film (light release film) having a low peeling force is peeled from the adhesive sheet and bonded to a first adherend, and then a release film (heavy release film) having a relatively large peeling force is peeled and bonded to a second adherend. By providing a difference in peeling force between the release films temporarily attached to the front and back surfaces of the pressure-sensitive adhesive sheet, the light release film can be selectively peeled off when the pressure-sensitive adhesive sheet is attached to the first adherend, and therefore, the workability of attachment can be improved.
Since the adhesive strength of the pressure-sensitive adhesive differs between before and after photocuring in the photocurable pressure-sensitive adhesive sheet, the adhesiveness (peelability) between the light-release film and the heavy-release film and each pressure-sensitive adhesive sheet is adjusted in consideration of the adhesive properties of the pressure-sensitive adhesive sheet after photocuring. In the case where the adhesive composition does not contain an ultraviolet absorber, the magnitude relationship of the peeling force between one release film and the other release film does not change before and after photocuring. In contrast, when the photocurable adhesive composition contains an ultraviolet absorber, the increase in the peel force of the first release film on the light irradiation surface tends to be significantly larger than the increase in the peel force of the second release film disposed on the opposite surface.
Therefore, in the release film-equipped adhesive sheet of the present invention, it is preferable that the first release film 10 on the light irradiation surface is a heavy release film and the second release film 20 on the opposite surface is a light release film. That is, the peeling force between the first release film 10 and the adhesive sheet 50 is preferably larger than the peeling force between the second release film 20 and the adhesive sheet 50.
If the peeling force between the first release film 10 (heavy release film) and the adhesive sheet 50 is too large, when the first release film 10 is peeled from the surface of the adhesive sheet 50 in a state where the adhesive sheet 50 is bonded to a first adherend, there may be a problem that the adhesive sheet is deformed, and the adhesive sheet is peeled from the adherend. The peeling force between the pressure-sensitive adhesive sheet 50 and the first release film 10 after photocuring is preferably 0.1 to 1.1N/50mm, more preferably 0.2 to 0.8N/50mm, and further preferably 0.3 to 0.7N/50 mm. The peeling force between the release film and the adhesive sheet was determined by the stretching speed: measured value obtained by 180 ℃ peel test of 0.3 m/min. In the present invention, by setting the Si atom content in the release layer 15 of the first release film 10 in the above range, an excessive increase in the peeling force between the pressure-sensitive adhesive sheet and the first release film after photocuring can be suppressed.
When the ultraviolet absorber is contained in the photocurable adhesive composition, the reason why the peeling force of the first release film increases and the reason why an excessive increase in the peeling force after photocuring the adhesive composition can be suppressed by adjusting the Si content of the release layer are not clear, but it is presumed that the increase is related to the reaction of the unreacted thermally reactive functional group in the release layer with the compound in the adhesive composition.
As described above, most of the ultraviolet light irradiated to the photocurable adhesive composition containing an ultraviolet absorber is absorbed by the ultraviolet absorber. Even when the sensitivity wavelength of the photopolymerization initiator and the wavelength of the irradiation light are shifted to the longer wavelength side (for example, 400nm or more), it is difficult to completely suppress light absorption by the ultraviolet absorber. When the ultraviolet absorber absorbs light, the light energy is converted into heat energy, and the temperature rises. In particular, in the vicinity of the interface between the release layer 15 and the adhesive composition layer 55 on the light irradiation surface side, the temperature is likely to rise because the amount of light absorption by the ultraviolet absorber is large. When the temperature rises under light irradiation, a thermosetting reaction is easily progressed in addition to a photocuring reaction. Therefore, it is considered that unreacted heat-reactive functional groups (vinyl group, alkenyl group, alkoxysilyl group, silanol group, hydrosilyl group, etc.) in the release layer 15 react with compounds in the adhesive composition, and the adhesive force (peeling force) increases.
By reducing the Si atom content per unit area of the silicone-based releasing layer 15, the amount of unreacted thermally reactive functional groups in the releasing layer 15 decreases. Therefore, in the present invention, it is considered that the amount of residual reactive functional groups in the release layer 15 that can react with the compound in the adhesive composition layer 15 is small, and an excessive increase in the peeling force between the adhesive sheet 50 and the release film 10 after photocuring can be suppressed.
As described above, the light irradiation of the adhesive composition may be performed from either the support substrate side or the cover sheet side, or may be performed from both sides. When the light irradiation is performed from the supporting substrate side, the release film 10 including the silicone-based release layer 15 described above may be used as the supporting substrate to which the adhesive composition is applied. When light irradiation is performed from the cover sheet side, the release film 10 including the silicone-based release layer 15 described above may be used as the cover sheet attached to the pressure-sensitive adhesive composition layer 55.
When light is irradiated from both sides, the release film described above may be used for either the support base material or the cover sheet. The release film described above may also be used for both the support base material and the cover sheet. As described in japanese patent application laid-open No. 2014-65754, when both surfaces are irradiated with light while being transported along a folded path in which the transport direction is reversed, it is preferable to use the above-described release film for the surface to which light is first irradiated.
[ uses of adhesive sheets ]
The photocurable adhesive sheet has high visible light transmittance and ultraviolet blocking property, and is therefore suitable as an optical adhesive for display devices and input devices for displays, which require ultraviolet blocking property. Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. As the input device, a touch panel is exemplified. The photocurable adhesive sheet can be used for bonding a display device to an input device, bonding a transparent plate disposed on the surface of the display device or the input device, or the like.
When a release film-equipped adhesive sheet having release films temporarily attached to both sides thereof is used, the light release film (second release film 20) is first peeled off to expose the second main surface of the adhesive sheet 50, and the adhesive sheet is attached to the first adherend. Then, the heavy release film (first release film 10) is peeled off to expose the first main surface of the adhesive sheet 50, and the second adherend is bonded thereto. The release films on both sides may be peeled off and then bonded to an adherend. In the case where the adhesive sheet is photocurable, the adhesive sheet after being bonded to an adherend may be further irradiated with light. By further photo-curing the adhesive sheet after the adhesive sheet is bonded to an adherend, the reliability of adhesion to the adherend may be improved.
Examples
The present invention will be further described below by way of examples and comparative examples, but the present invention is not limited to these examples.
[ preparation of Photocurable adhesive composition ]
< adhesive composition A >)
In the synthesis of a compound consisting of 2-ethylhexyl acrylate (2 EHA): 78 parts by weight, N-vinyl-2-pyrrolidone (NVP): 18 parts by weight, and 2-hydroxyethyl acrylate (HEA): 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, BASF) as a photopolymerization initiator was added to 4 parts by weight of the monomer mixture: 0.035 parts by weight, and 2, 2-dimethoxy-1, 2-diphenylethan-1-one (Irgacure 651, BASF.): 0.035 weight portions. This composition was irradiated with ultraviolet rays and prepolymerized until the viscosity at room temperature reached about 20 pas, to obtain a prepolymer having a polymerization rate of about 8%.
100 parts by weight of prepolymer was added with hexanediol diacrylate (HDDA): 0.15 part by weight of a silane coupling agent (KBM-403, manufactured by shin-Etsu chemical industry): 0.3 part by weight of a 15% by weight Butyl Acrylate (BA) solution of an ultraviolet absorber (2, 4-bis- [ {4- (4-ethylhexyloxy) -4-hydroxy } -phenyl ] -6- (4-methoxyphenyl) -1,3, 5-triazine; manufactured by BASF as "Tinosorb S"): 4.7 parts by weight (ultraviolet absorber: 0.7 part by weight), and bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide ("Irgacure 819" from BASF) as a polymerization initiator: 0.15 part by weight, an ultraviolet-curable acrylic adhesive composition a was obtained.
< adhesive composition B >
An adhesive composition B was obtained in the same manner as in the preparation of the adhesive composition 1, except that the amount of the post-addition polymerization initiator was changed from 0.15 parts by weight to 0.1 parts by weight.
< adhesive composition C >
In the preparation of the prepolymer composition, the composition of the monomer mixture was changed to 2 EHA: 30.5 parts by weight of isostearyl acrylate (ISTA): 30.5 parts by weight of isobornyl acrylate (IBXA): 19 parts by weight, and 4-hydroxybutyl acrylate (4 HBA): 20 parts by weight of a photopolymerization initiator, wherein the addition amount of the photopolymerization initiator is 1-hydroxycyclohexyl phenyl ketone: 0.05 parts by weight, and 2, 2-dimethoxy-1, 2-diphenylethan-1-one: 0.05 part by weight, other than these changes, the adhesive composition C was obtained in the same manner as in the preparation of the adhesive composition 1.
[ preparation of Silicone Release agent solution ]
< Release agent solution A >
A30% toluene solution (LTC 761, manufactured by Toray Dow Corning) of addition-type silicone containing a hexenyl group (an addition-type silicone release agent containing polyorganosiloxane having a hexenyl group in the molecule and a polyorganosiloxane crosslinking agent having a hydrosilyl group in the molecule) was prepared by using a mixed solvent of toluene and hexane at a volume ratio of 1: 30 parts BY weight of a silicone dispersion ("BY 24-850" manufactured BY Toray Dow Corning): 0.9 part by weight, and a platinum catalyst for curing silicone (SRX 212, Toray Dow Corning Co., Ltd.): 2 parts by weight were diluted to give the given concentrations shown in Table 1, and a mold release agent solution A was prepared.
< Release agent solution B >
A release agent solution B was prepared by diluting 10 parts by weight of a 30% toluene solution of vinyl group-containing addition type silicone (KS-847T, manufactured by shin-Etsu chemical Co., Ltd.) and 1 part by weight of a platinum catalyst for curing silicone (CAT-PL-50T, manufactured by shin-Etsu chemical Co., Ltd.) with a mixed solvent of toluene and hexane at a volume ratio of 1:1 to give the concentrations shown in Table 1.
[ example 1]
< production of base Material Release film >
A release agent solution B prepared so that the solid content of silicone became 1.25 wt% was applied to one surface of a biaxially oriented polyester film (lumiror XD500P manufactured by Toray Advanced Materials Korea) having a thickness of 75 μm using a wire rod (#15), and heated for 1 minute using a hot air dryer at 130 ℃.
< production of Cap mold Release film >
A mold release agent solution a prepared so that the solid content of silicone became 0.7 wt% was applied to one surface of a biaxially oriented polyester film ("lumiror XD 500P" manufactured by Toray Advanced Materials Korea) having a thickness of 75 μm using a wire rod (#9), and heated for 1 minute using a hot air dryer at 130 ℃.
< production of adhesive sheet with Release film >
The pressure-sensitive adhesive composition a was applied to the release layer-formed surface of the release film coated with the substrate in a thickness of 150 μm to form a coating layer, and a lid release film was bonded to the surface of the coating layer to obtain a laminate. At the illumination intensity: 6.5mW/cm2Accumulated light amount: 1500mJ/cm2Under the conditions of (1), the laminate was irradiated with ultraviolet rays from the lid release film side to photocure the coating layer, thereby obtaining a photocurable adhesiveThe adhesive sheet has a release film on both sides of the agent layer.
Examples 2 to 6 and comparative examples 1 to 3
The kind and concentration of the release agent solution, the wire diameter (type) of the wire rod, and the kind of the adhesive composition in the production of the lid release film were changed as shown in table 1, and a photocurable adhesive sheet having release films on both surfaces was produced in the same manner as in example 1 except for these changes.
[ evaluation ]
< Si atom content of mold release layer >
The amount of Si atoms per unit area (mg/m) was calculated by fluorescent X-ray analysis (XRF) of the surface of the mold release layer of the cap mold release film2). In the XRF analysis, a scanning fluorescent X-ray analyzer (ZSX 100e, physical product) including a vertical rhodium tube as an X-ray source was used, and the analysis area: 30mm phi, analytical elements: si, spectral crystallization: RX4, output: the measurement was carried out under the conditions of 50kV and 70 mA.
< peeling force of mold release film >
The pressure-sensitive adhesive sheet with a release film was cut into a 50mm width, and a 180 ° peel test was performed at a tensile speed of 0.3 m/min in an environment of 23 ℃ using a tensile tester, and the peel force of each of the substrate release film and the cover release film when peeled from the pressure-sensitive adhesive sheet was measured.
[ evaluation results ]
The evaluation results of the structure of the release layer (the type of release agent solution, the silicone concentration, the thickness, and the Si amount), the type of the adhesive, and the peeling force in the cap release films of examples and comparative examples are shown in table 1.
[ Table 1]
Figure BDA0002510840770000181
In examples 1 to 6 and comparative examples 1 to 3, the peeling force of the substrate release film was about 0.2N/50mm, and no significant difference was observed. In comparative example 3 in which the same release agent was used for the base release film and the lid release film, the peel force of the lid release film after photocuring of the pressure-sensitive adhesive sheet was 10 times or more the peel force of the base release film, and peeling was difficult. In comparative example 1 in which the kind of silicone release agent and the composition of the adhesive agent of the lid release film were changed, the lid release film peel strength was significantly increased in the same manner as in comparative example 3. From these results, it was found that when a laminate in which a photocurable adhesive sheet containing an ultraviolet absorber was sandwiched between 2 release films was photocured by light irradiation, the release sheet on the light irradiation surface exhibited a large peeling force.
In comparative example 2 in which the concentration of the release agent solution and the coating thickness in the production of the cap release film were made larger than those in comparative example 1, the Si content per unit area of the release layer was increased, and the peel force of the cap release film after photocuring of the adhesive sheet was also made larger than that in comparative example 1.
In examples 1, 4 and 5 in which the amount of Si per unit area was reduced by adjusting the concentration and coating thickness of the release agent solution in the production of the lid release film, the peeling force of the lid release film after photocuring of the adhesive sheet was reduced to less than 1N/50mm, and defects such as deformation of the adhesive sheet at the time of peeling were less likely to occur. From the results of examples 1, 4 and 5 and comparative examples 1 and 2, it is understood that the peeling force of the lid release film after photocuring of the adhesive sheet is reduced by reducing the amount of Si per unit area of the release layer.
In examples 2 and 3 in which the same lid release film as in example 1 was used but the composition of the pressure-sensitive adhesive was changed, the peel force of the lid release film was the same as that in example 1. In example 6 using the same pressure-sensitive adhesive sheet as in example 2, the lid release film after photocuring of the pressure-sensitive adhesive sheet was also excellent in peelability.
From the above results, it is found that by providing a release sheet having a release layer having an Si atomic weight per unit area within a predetermined range on a photocurable pressure-sensitive adhesive sheet containing an ultraviolet absorber, an excessive increase in the peeling force of the release film after photocuring the pressure-sensitive adhesive sheet can be suppressed.

Claims (9)

1. A release film-equipped adhesive sheet comprising:
photocurable adhesive sheet having first and second main surfaces, and
a first release film temporarily attached to the first main surface of the adhesive sheet,
wherein the content of the first and second substances,
the first release film includes a release layer on a film base,
the release layer is in contact with the adhesive sheet,
the adhesive sheet comprises a photocurable acrylic polymer and an ultraviolet absorber,
the demoulding layer is an organic silicon demoulding layer, and the content of Si atoms is 0.02-0.07 g/m2。
2. The release film-equipped adhesive sheet according to claim 1, further comprising a second release film temporarily attached to the second main surface of the adhesive sheet.
3. The release film-equipped adhesive sheet according to claim 2,
the peeling force of the first release film from the adhesive sheet is greater than the peeling force of the second release film from the adhesive sheet.
4. The release film-equipped adhesive sheet according to any one of claims 1 to 3,
the adhesive sheet has a light transmittance at a wavelength of 380nm of 10% or less.
5. The release film-equipped adhesive sheet according to any one of claims 1 to 3,
the acrylic polymer contains, as a monomer component, a polyfunctional monomer component having 2 or more polymerizable functional groups in 1 molecule.
6. The release film-equipped adhesive sheet according to any one of claims 1 to 3,
the ultraviolet absorbent is triazine ultraviolet absorbent.
7. The release film-equipped adhesive sheet according to any one of claims 1 to 3,
the adhesive sheet contains 0.1 to 10 parts by weight of the ultraviolet absorber per 100 parts by weight of the acrylic polymer.
8. A method for producing a release film-equipped adhesive sheet, comprising:
a photocurable adhesive sheet having a first main surface and a second main surface,
A first release film temporarily attached to the first main surface of the adhesive sheet, and
a second release film temporarily attached to the second main surface of the adhesive sheet,
the method comprises the following steps:
a step of preparing a laminate in which a photocurable adhesive composition layer containing an acrylic monomer and/or a partial polymer of the acrylic monomer, an ultraviolet absorber, and a photopolymerization initiator is sandwiched between a first release film and a second release film; and
a step of irradiating the laminate with light from the first release film side to photocure the photocurable adhesive composition,
wherein the content of the first and second substances,
the first release film has a release layer on a surface of a film base material on a side in contact with the photocurable adhesive composition,
the demoulding layer is an organic silicon demoulding layer, and the content of Si atoms is 0.02-0.07 g/m2。
9. The method for producing a release film-equipped adhesive sheet according to claim 8,
the photopolymerization initiator has sensitivity at a wavelength longer than 400 nm.
CN201880076662.3A 2017-12-21 2018-10-15 Release film-attached pressure-sensitive adhesive sheet and method for producing same Active CN111465668B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2017245614A JP2019112505A (en) 2017-12-21 2017-12-21 Pressure sensitive adhesive sheet with release film and manufacturing method thereof
JP2017-245614 2017-12-21
PCT/JP2018/038375 WO2019123799A1 (en) 2017-12-21 2018-10-15 Adhesive sheet with mold release film and method for producing same

Publications (2)

Publication Number Publication Date
CN111465668A CN111465668A (en) 2020-07-28
CN111465668B true CN111465668B (en) 2022-05-10

Family

ID=66993289

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201880076662.3A Active CN111465668B (en) 2017-12-21 2018-10-15 Release film-attached pressure-sensitive adhesive sheet and method for producing same

Country Status (6)

Country Link
JP (2) JP2019112505A (en)
KR (1) KR102567694B1 (en)
CN (1) CN111465668B (en)
SG (1) SG11202005787TA (en)
TW (1) TWI791076B (en)
WO (1) WO2019123799A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019244986A1 (en) * 2018-06-21 2019-12-26 凸版印刷株式会社 Protection film and sheet
JP7312679B2 (en) * 2019-11-19 2023-07-21 日東電工株式会社 OPTICAL FILM WITH ADHESIVE AND METHOD FOR MANUFACTURING THE SAME
JP2021127413A (en) 2020-02-14 2021-09-02 日東電工株式会社 Release film-attached adhesive sheet and method for producing the same
WO2023074555A1 (en) * 2021-10-27 2023-05-04 日東電工株式会社 Photocurable adhesive sheet
WO2023074554A1 (en) * 2021-10-27 2023-05-04 日東電工株式会社 Photocurable adhesive sheet
JP7435889B1 (en) 2023-07-05 2024-02-21 王子ホールディングス株式会社 Adhesive sheets and laminates

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015151473A (en) * 2014-02-14 2015-08-24 日東電工株式会社 Sheet containing photoreaction product layer and production method of the same
CN105008481A (en) * 2013-03-11 2015-10-28 琳得科株式会社 Adhesive sheet, and production method for processed device-related members
JP2016155981A (en) * 2015-02-26 2016-09-01 日東電工株式会社 Ultraviolet-curable acrylic adhesive composition, ultraviolet-curable acrylic adhesive layer, polarization film with adhesive layer, method for producing ultraviolet-curable acrylic adhesive layer and image display device
JP2017003906A (en) * 2015-06-15 2017-01-05 日東電工株式会社 Polarization film with adhesive layer on both sides, and image formation apparatus

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5107761B2 (en) * 2008-03-24 2012-12-26 三菱樹脂株式会社 Release film
JP2012193221A (en) 2011-03-15 2012-10-11 Mitsubishi Plastics Inc Adhesive sheet
JP5945393B2 (en) 2011-09-30 2016-07-05 日東電工株式会社 Adhesive sheet
JP5903978B2 (en) * 2012-03-28 2016-04-13 住友化学株式会社 Method for producing optical member with adhesive
JP2014189660A (en) * 2013-03-27 2014-10-06 Lintec Corp Method for manufacturing laminate, adhesive roll and adhesive layer-containing laminated structure using laminate
JP2014226923A (en) * 2013-05-28 2014-12-08 三菱樹脂株式会社 Laminated film

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105008481A (en) * 2013-03-11 2015-10-28 琳得科株式会社 Adhesive sheet, and production method for processed device-related members
JP2015151473A (en) * 2014-02-14 2015-08-24 日東電工株式会社 Sheet containing photoreaction product layer and production method of the same
JP2016155981A (en) * 2015-02-26 2016-09-01 日東電工株式会社 Ultraviolet-curable acrylic adhesive composition, ultraviolet-curable acrylic adhesive layer, polarization film with adhesive layer, method for producing ultraviolet-curable acrylic adhesive layer and image display device
JP2017003906A (en) * 2015-06-15 2017-01-05 日東電工株式会社 Polarization film with adhesive layer on both sides, and image formation apparatus

Also Published As

Publication number Publication date
KR102567694B1 (en) 2023-08-18
TW201930521A (en) 2019-08-01
KR20200100128A (en) 2020-08-25
WO2019123799A1 (en) 2019-06-27
CN111465668A (en) 2020-07-28
JP2023009099A (en) 2023-01-19
SG11202005787TA (en) 2020-07-29
TWI791076B (en) 2023-02-01
JP2019112505A (en) 2019-07-11

Similar Documents

Publication Publication Date Title
CN111465668B (en) Release film-attached pressure-sensitive adhesive sheet and method for producing same
TW201728683A (en) Active energy ray curable hot melt silicone composition, cured product thereof, and method of producing film
JP6323851B2 (en) Photoreactive material layer-containing sheet and method for producing the same
WO2020054745A1 (en) Adhesive sheet, layered product and method for producing layered product
JP7251073B2 (en) Adhesive sheet, adhesive sheet with release sheet, laminate, and method for producing laminate
WO2021161874A1 (en) Adhesive sheet with release film and manufacturing method thereof
WO2024019151A1 (en) Method for producing adhesive sheet and method for producing optical film with adhesive sheet
WO2024019153A1 (en) Method for producing pressure-sensitive adhesive sheet and method for producing optical film with pressure-sensitive adhesive sheet
WO2024019159A1 (en) Adhesive sheet and optical layered product
WO2024019152A1 (en) Method for producing adhesive sheet, method for producing laminate, and method for producing adhesive sheet-bearing optical film
WO2024019158A1 (en) Method for producing adhesive sheet and method for producing optical film including adhesive sheet
JP7285641B2 (en) Adhesive sheet with release film and method for producing the same
JP7279339B2 (en) Adhesive sheet, laminate, and method for producing laminate
WO2023074554A1 (en) Photocurable adhesive sheet
WO2024019160A1 (en) Optical laminate and image display device
WO2024019161A1 (en) Optical layered body
TW202413573A (en) Adhesive Sheets and Optical Laminates
TW202413572A (en) Method for manufacturing adhesive sheet and method for manufacturing optical film attached to adhesive sheet
JP2005023115A (en) Pressure-sensitive double-sided adhesive tape or sheet
TW202411374A (en) Adhesive sheet and optical multilayer body
KR20240062967A (en) Release liner
TW202334359A (en) Optical Adhesive Sheet

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant