KR20220107137A - Optical adhesive composition, and adhesive film, adhesive sheet using the same - Google Patents

Abstract

The present invention provides an optical adhesive composition, an adhesive film using the same, and an adhesive sheet capable of forming an adhesive layer having step following for steps such as frame printing of an attached object; handling of rework; and excellent wet heat durability. The optical adhesive composition contains a copolymerized vinyl monomer which does not have a carboxyl group in a functional group, and has one of an alkyl group, a hydroxyl group, an alkoxy group, and an aromatic group; a copolymer which is obtained by copolymerizing at least two types selected from a compound group of a nitrogen-containing vinyl monomer; (F) a (meth) acrylate monomer; (G) a (meth) acrylate monomer; (E) a thermocrosslinking agent; and (H) a photocrosslinking agent.

Description

An adhesive composition for optics, an adhesive film using the same, and an adhesive sheet {OPTICAL ADHESIVE COMPOSITION, AND ADHESIVE FILM, ADHESIVE SHEET USING THE SAME}

The present invention relates to an adhesive composition for optics, an adhesive film using the same, and an adhesive sheet. More specifically, an optical pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer that has both step followability for steps such as frame printing of an adherend, handling properties during rework (ease of peeling from an adherend), and excellent moisture and heat durability is about providing Moreover, it is related with providing the adhesive film and adhesive sheet using the said adhesive composition for optics.

In addition, the pressure-sensitive adhesive layer crosslinked by a thermal crosslinking agent using the pressure-sensitive adhesive composition for optics according to the present invention has a step followability to steps (irregularities) such as frame printing disposed on the surface of an adherend and handling properties at the time of rework. good Further, the pressure-sensitive adhesive layer after crosslinking in two steps of crosslinking with the thermal crosslinking agent and then crosslinking with a photocrosslinking agent is excellent in wet heat durability.

In addition, the adhesive composition for optics of the present invention, an adhesive film using the same, and an adhesive sheet are included in various electronic devices when bonding an optical film to various displays, bonding between optical films to produce a laminate of an optical film, and It can be used for fixing optical parts and electronic parts to be used.

On the other hand, in the present invention, the "wet heat durability" of the pressure-sensitive adhesive layer means that the pressure-sensitive adhesive layer is left for a long time in a moist heat environment, and then it is taken out under a room temperature environment (temperature: 23°C x 50%RH) without causing significant foaming due to moisture and is transparent It means durability.

DESCRIPTION OF RELATED ART In recent years, the electronic device which combined the display (image display apparatus) and the touch panel as an input device has spread. As a display (image display device) to which a touchscreen is applied, a liquid crystal display (LCD), an electroluminescence display (inorganic EL, organic EL), etc. are mentioned. Moreover, liquid crystal TV, inorganic EL TV, organic electroluminescent TV, portable terminal, a mobile phone, an electronic paper, an electronic book terminal, a personal computer etc. are mentioned as a specific electronic device in which a touchscreen is used as an input device.

In these electronic devices, it is calculated|required by the adhesive layer for bonding together the optical member which comprises a touchscreen to be equipped with functions, such as step|step difference followable|trackability and wet-and-heat durability.

Conventionally, in order to obtain the adhesive layer which has step|step difference followable|trackability, various proposals are made (patent documents 1 - 3). Moreover, the proposal for obtaining the adhesive layer which has step|step difference followability|trackability and wet-heat durability is also proposed (patent document 4).

In Patent Document 1, when the transparent panel and the image display device are fixed, the adhesion is excellent in the step caused by the decorative portion formed on the transparent panel surface or the image display device surface, and the step portion is in a high temperature environment. A double-sided pressure-sensitive adhesive sheet capable of suppressing foaming or peeling is disclosed.

Further, in Patent Document 2, there are few bubbles at the printing edge at the time of forming the pressure-sensitive adhesive layer due to the printing step, and the decorative printing does not generate bubbles when bonding to an adherend, and dents do not easily occur even when a load is applied. A layered surface protection film is disclosed.

In addition, in Patent Document 3, in the photopolymerizable pressure-sensitive adhesive for a touch panel having a conductive film made of a metal or metal oxide, whitening and foaming are suppressed by excellent heat-and-moisture stability and foaming resistance, and there is no odor or skin irritation. , furthermore, a photopolymerizable pressure-sensitive adhesive having no corrosive properties to metals or metal oxides, and a pressure-sensitive adhesive sheet using the same are described.

Moreover, in patent document 4, the acrylic polymer compound used for the adhesive composition for touch panels excellent in transparency, adhesiveness, durability, corrosion resistance, step|step difference followability, high dielectric constant, and coatability is described.

Japanese Patent Laid-Open No. 2012-211282 Japanese Laid-Open Patent Publication No. 2015-221531 Japanese Patent Laid-Open No. 2013-256552 Japanese Patent Laid-Open No. 2012-041456

In the double-sided pressure-sensitive adhesive sheet described in Patent Document 1, the performance regarding the print level difference followability is satisfied at the point where the value of the storage elastic modulus of the pressure-sensitive adhesive layer is suppressed to a specific numerical range to provide a flexible pressure-sensitive adhesive layer. However, if the adhesive force of an adhesive layer is raised, after bonding an optical member to a to-be-adhered body, when the need arises to bond again, it may be difficult to peel, and the handling property (re-bonding operability) at the time of so-called rework (re-bonding operability) is inferior. Conversely, when the handling property at the time of the rework of an adhesive layer is improved, the adhesive force after bonding an optical member to a to-be-adhered body is too low, and a possibility of peeling will arise. For this reason, in the double-sided adhesive sheet of patent document 1, the problem that coexistence of ensuring the handling property at the time of rework of an adhesive layer, and making high adhesive force after bonding an optical member together to a to-be-adhered body is difficult there was.

In addition, in Patent Document 2, a decorative printing layer such as a figure or character is formed on one side of the transparent resin film, and a photopolymerization initiator is included on the upper portion of the portion where the decorative print layer is not formed and on the decorative print layer. After apply|coating the photocurable resin composition which has fluidity|liquidity to do, UV irradiation and photocuring are formed, and obtaining the surface protection film with a decorative printing layer is disclosed. The surface protection film with the decorative printing layer of Patent Document 2 is coated with a photocurable resin composition having fluidity containing a photopolymerization initiator and then UV-irradiated to form an adhesive layer that is photocured, so the adhesive after UV curing It is said that the printing step can be filled regardless of the layer's flexibility. However, since the adhesive layer which concerns on invention of patent document 2 apply|coats a liquid adhesive composition, there existed a problem that it was difficult to form the adhesive layer of a thick film. Moreover, applying a liquid photocurable resin composition to a printing level|step difference part and filling a printing level difference has the subject that handling is complicated.

Further, in Patent Document 3, (a-1) 40 to 92% by weight of alkyl (meth)acrylate, (a-2) 5 to 20% by weight of a hydroxyl group-containing monomer, (a-3) water-soluble N-substituted acrylamide 3 to An isocyanate-based crosslinking agent with respect to 100 parts by weight of the monomer group (A) containing 25% by weight and substantially not containing an acidic group-containing monomer (total monomers are 100% by weight) or its partial polymerization product (A') and/or 0.01 to 2 parts by weight of a polyfunctional monomer (B) and 0.1 to 2 parts by weight of a photoinitiator (C) are disclosed. If it is the photopolymerizable adhesive of patent document 3, it is said that step|step difference followable|trackability and re-peelability are favorable. According to Examples 1 to 6 of Patent Document 3, a photopolymerizable pressure-sensitive adhesive is applied to a substrate to form a coating film having a thickness of 300 µm, and a PET film having a thickness of 25 µm subjected to release treatment on the surface of the coating film is subjected to a release treatment surface. It is installed so that it may come into contact with this, and photopolymerization is carried out by UV irradiation in nitrogen gas atmosphere, and the adhesive sheet is produced. However, since the value of the adhesive force of the obtained adhesive sheet is the range of 14-25 N/25 mm, when re-bonding the adhesive sheet bonded to a to-be-adhered body, it is difficult to peel an adhesive sheet from a to-be-adhered body, and it is difficult to peel at the time of rework. There was a problem that the handling property was poor.

Further, in Patent Document 4, (a) a (meth)acrylic acid ester-based monomer having a hydrocarbon group having 1 to 12 carbon atoms, (b) a hydroxyl group-containing (meth)acrylic acid ester-based monomer, (c) a monomer containing an amide group; And (d) obtained by copolymerizing a monomer component containing a vinyl ester-based monomer, the resin acid value is 0.1 mgKOH / g or less, the weight average molecular weight is 400,000 to 2 million, Tg is -80 to 0 ℃, An acrylic polymer compound having a dielectric constant of 3 to 6 and used in a pressure-sensitive adhesive composition for a touch panel is disclosed. In the acrylic polymer compound of Patent Document 4, "a hydroxyl group-containing acrylic acid ester monomer is preferable, a functional group that serves as a reaction site with a crosslinking agent can be provided to the polymer compound, and the crosslinked product obtained by crosslinking is suitable as an adhesive for elasticity 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularly preferable from the viewpoint of increasing the cohesive force by providing Paragraph [0021] of Patent Document 4).

Moreover, in the adhesive sheet of patent document 4, "in order to improve the designability of a product and to aim at differentiation, the printed layer is formed in the protective transparent plate in many cases. This printing ink layer, a layer such as silver paste used in various circuits, and the level difference occurring in the FPD part, etc., in many cases have a step difference of about 10 to 30 µm in the base sheet or film, and bubbles when bonding by the pressure-sensitive adhesive sheet There is a problem that occurs. This is due to the lack of followability to the step difference of the pressure-sensitive adhesive layer. In the adhesive properties of the pressure-sensitive adhesive sheet obtained from the pressure-sensitive adhesive composition, appropriate Tg and gel fraction are closely related to this level difference followability. The gel fraction of the pressure-sensitive adhesive is preferably about 30 to 70%, more preferably about 40 to 65%” (paragraph [0081] of Patent Document 4).

However, among the pressure-sensitive adhesive sheets of Examples 1 to 12 of Patent Document 4, the pressure-sensitive adhesive sheets of Examples 1, 2, 5, 6, 8, and 10 have a thickness of 50 µm and a thin pressure-sensitive adhesive layer. Since haze value exceeded 4.0 %, there existed a problem that heat-and-moisture resistance needed to be improved further.

As described above, in the prior art, an adhesive composition for optics capable of forming an adhesive layer having good step followability to steps such as frame printing of an adherend, handling properties at the time of rework, and excellent wet and heat durability, and the use of the same It was difficult to obtain an adhesive film and an adhesive sheet.

The present invention has been made in view of the above problems, and an optical pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer that has both step followability to steps such as frame printing of an adherend, handling properties during rework, and excellent wet and heat durability, and this It makes it a subject to provide the used adhesive film and adhesive sheet.

The present inventors diligently researched the above subject, and an acrylic polymer, a (meth)acrylate monomer having an (meth)acryloyl group and an allyl ether group in one molecule, and having two or more ethylenically unsaturated groups, and an alkylene oxide A pressure-sensitive adhesive layer obtained by crosslinking an optical pressure-sensitive adhesive composition containing a (meth)acrylate monomer having two or more ethylenically unsaturated groups in one molecule having a group, a thermal crosslinking agent, and a photocrosslinking agent with a thermal crosslinking agent, and further by a photocrosslinking agent The pressure-sensitive adhesive layer (1st step) before crosslinking is excellent in step followability and handling during rework By discovering that the adhesive layer (2nd step) formed by making it was excellent in wet-heat durability, this invention was able to be completed.

The optical pressure-sensitive adhesive composition according to the present invention includes an acrylic polymer, a (meth)acrylate monomer having an acryloyl group and an allyl ether group in one molecule, and having two or more ethylenically unsaturated groups, and an alkylene oxide group. An optical pressure-sensitive adhesive composition containing a (meth)acrylate monomer having two or more ethylenically unsaturated groups in one molecule, a thermal crosslinking agent, and a photocrosslinking agent is crosslinked in two steps: crosslinking with a thermal crosslinking agent and crosslinking with a photocrosslinking agent , it has the characteristic that the pressure-sensitive adhesive layer having different physical properties can be formed in two steps.

That is, the present invention is composed of the first-stage pressure-sensitive adhesive layer having good step followability for steps such as frame printing of an adherend and handling properties during rework, and the second-stage pressure-sensitive adhesive layer having excellent wet and heat durability. It is making it a technical idea to provide the adhesive composition for optics which can form different adhesive layers in two steps, the adhesive film using the same, and an adhesive sheet.

In order to solve the above problems, the present invention does not have a carboxyl group in the functional group, and at least two or more selected from the group consisting of a copolymerizable vinyl monomer having any one of an alkyl group, a hydroxyl group, an alkoxy group, and an aromatic group, and a nitrogen-containing vinyl monomer. A copolymer obtained by copolymerizing (F) a (meth) acrylate monomer having an (meth) acryloyl group and an allyl ether group in one molecule, and having two or more ethylenically unsaturated groups, and (G) an alkylene oxide group It provides an optical pressure-sensitive adhesive composition comprising a (meth)acrylate monomer having two or more ethylenically unsaturated groups in one molecule, (E) a thermal crosslinking agent, and (H) a photocrosslinking agent.

Further, the copolymer is (B) a nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) relative to a total of 100 parts by weight of at least one or more kinds of alkyl (meth) acrylate monomers having a C1-C18 alkyl group in the copolymer (A). ) 2.0 to 10 parts by weight in total of at least one acrylate monomer, (C) 1.0 to 10 parts by weight in total of at least one or more polyalkylene glycol mono(meth)acrylate monomers, and (D) having a hydroxyl group It is a copolymer with a weight average molecular weight of 200,000 to 1 million in which at least one or more total of 0.5 to 10 parts by weight of the copolymerizable vinyl monomer is copolymerized, and the pressure-sensitive adhesive composition for optics is (E) with respect to 100 parts by weight of the above (A). 0.01 to 5 parts by weight of the thermal crosslinking agent and 0.1 to 10 parts by weight of (F) a (meth)acrylate monomer having an acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups and (G) 0.1 to 10 parts by weight of a (meth)acrylate monomer having two or more ethylenically unsaturated groups in one molecule having an alkylene oxide group, and 0.01 to 5 parts by weight of the (H) photocrosslinking agent. It is preferable to contain

In addition, the total light transmittance of the pressure-sensitive adhesive layer having a thickness of 250 μm formed by crosslinking the optical pressure-sensitive adhesive composition in two steps of crosslinking with the (E) thermal crosslinking agent followed by crosslinking with the (H) photocrosslinking agent is 90% or more. Moreover, it is preferable that haze value is 1.0 % or less.

In addition, the pressure-sensitive adhesive layer having a thickness of 250 μm formed by crosslinking the optical pressure-sensitive adhesive composition in two steps of (E) cross-linking with the thermal cross-linking agent and then (H) cross-linking with the photo cross-linking agent was heated at a temperature of 60° C.×90% RH. It is preferable that haze value at the time of taking out to room temperature environment (temperature 23 degreeC x 50%RH) after leaving it to stand in the atmosphere for 240 hours is 4.0 % or less.

In addition, in the copolymer (A) in a total of 100 parts by weight of at least one or more types of alkyl (meth)acrylate monomers having C1-C18 alkyl groups, alkyl (meth)acrylates having C8-C18 alkyl groups It is preferable to contain it in the ratio of 50 weight part or more.

In addition, the copolymer is made by copolymerizing (C) a polyalkylene glycol mono (meth) acrylate monomer, and the optical pressure-sensitive adhesive composition has (G) two or more ethylenically unsaturated groups in one molecule having an alkylene oxide group. It consists of containing the (meth)acrylate monomer which has, and it is preferable that the average repeating number of the alkylene oxide of said (C) and said (G) is 4-14.

In addition, the present invention uses the above-mentioned pressure-sensitive adhesive composition for optics on one side of the substrate, and the pressure-sensitive adhesive layer formed by crosslinking with the (E) thermal crosslinking agent, or (E) following crosslinking with the thermal crosslinking agent, followed by the above (H) ) A pressure-sensitive adhesive film formed by laminating a pressure-sensitive adhesive layer crosslinked in two steps of crosslinking with a photocrosslinking agent, wherein the pressure sensitive adhesive layer after crosslinking with the (E) thermal crosslinking agent has an adhesive strength to soda glass of 10N/25mm or less In addition, the pressure-sensitive adhesive layer after crosslinking in two steps of (E) crosslinking with a thermal crosslinking agent followed by crosslinking with (H) a photocrosslinking agent has an adhesive strength to soda glass of 25N/25mm or more. film is provided.

In addition, the present invention is an adhesive film in which an adhesive layer crosslinked by the (E) thermal crosslinking agent is laminated on one side of a polyethylene phthalate resin film having a thickness of 188 μm using the optical adhesive composition, When the pressure-sensitive adhesive film is bonded to glass having a printing step of a printed layer having a thickness of 42 μm through the pressure-sensitive adhesive layer having a thickness of 100 μm, followability to the printing step is good, and foaming is performed around the printing step. It provides an adhesive film characterized in that there is no at all.

In addition, the present invention provides a film for a touch panel in which the adhesive film is used.

In addition, the present invention provides a pressure-sensitive adhesive sheet formed by laminating the pressure-sensitive adhesive layer crosslinked by the thermal crosslinking agent (E) between two release-treated release films using the pressure-sensitive adhesive composition for optics.

In addition, the present invention uses the optical pressure-sensitive adhesive composition on at least one side of the optical film, and the pressure-sensitive adhesive layer formed by crosslinking with the (E) thermal crosslinking agent, or (E) following crosslinking with the thermal crosslinking agent (E) H) Provided is an optical film with a pressure-sensitive adhesive layer formed by laminating a pressure-sensitive adhesive layer crosslinked in two steps of crosslinking with a photocrosslinking agent.

The optical pressure-sensitive adhesive composition according to the present invention includes an acrylic polymer, a (meth)acrylate monomer having an acryloyl group and an allyl ether group in one molecule, and having two or more ethylenically unsaturated groups, and an alkylene oxide group. It is an optical adhesive composition containing the (meth)acrylate monomer which has two or more ethylenically unsaturated groups in 1 molecule, a thermal crosslinking agent, and a photocrosslinking agent. Here, the (meth)acrylate monomer having a (meth)acryloyl group and an allylether group in one molecule and having two or more ethylenically unsaturated groups forms a cyclic compound when photocrosslinked with a photocrosslinking agent, The pressure-sensitive adhesive layer after crosslinking in two steps of crosslinking with a thermal crosslinking agent followed by crosslinking with a photocrosslinking agent has excellent moisture and heat durability.

In addition, the pressure-sensitive adhesive film and the pressure-sensitive adhesive sheet according to the present invention include an acrylic polymer, a (meth)acrylate monomer having a (meth)acryloyl group and an allylether group in one molecule, and having two or more ethylenically unsaturated groups, and an alkylene A pressure-sensitive adhesive layer crosslinked using an optical pressure-sensitive adhesive composition containing a (meth)acrylate monomer having two or more ethylenically unsaturated groups in one molecule having an oxide group, a thermal crosslinking agent, and a photocrosslinking agent is formed. The pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer that is crosslinked with a thermal crosslinking agent, and can be crosslinked in two steps: crosslinking with a thermal crosslinking agent followed by crosslinking with a photocrosslinking agent, or crosslinking with a thermal crosslinking agent followed by crosslinking with a photocrosslinking agent It is a pressure-sensitive adhesive layer crosslinked in two steps of crosslinking.

In this respect, according to the present invention, it is possible to provide a pressure-sensitive adhesive film and pressure-sensitive adhesive sheet having both step followability with respect to steps such as frame printing of an adherend, handling properties at the time of rework, and excellent wet and heat durability.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated based on preferable embodiment.

The optical pressure-sensitive adhesive composition of the present embodiment does not have a carboxyl group in a functional group, and at least two or more selected from the group consisting of a copolymerizable vinyl monomer having any one of an alkyl group, a hydroxyl group, an alkoxy group, and an aromatic group, and a nitrogen-containing vinyl monomer. A copolymer obtained by copolymerization, (F) having a (meth)acryloyl group and an allyl ether group in one molecule, and a (meth)acrylate monomer having two or more ethylenically unsaturated groups, (G) having an alkylene oxide group It is characterized by containing a (meth)acrylate monomer 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. In addition, a (meth)acryloyl group is a generic name of an acryloyl group and a methacryloyl group. The copolymer according to the pressure-sensitive adhesive composition for optics of the present embodiment is, for example, (A) at least one or more of an alkyl (meth)acrylate monomer having a C1-C18 alkyl group, and (B) a nitrogen-containing vinyl monomer or At least one or more of an alkoxy group-containing alkyl (meth) acrylate monomer, (C) at least one or more of a polyalkylene glycol mono (meth) acrylate monomer, and (D) at least a copolymerizable vinyl monomer having a hydroxyl group It is a copolymer which copolymerized 1 or more types.

As the (A) alkyl (meth) acrylate monomer having C1-C18 carbon atoms in the alkyl group, 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 At least 1 or more types, such as (meth)acrylate, are mentioned. Any one of linear, branched, and cyclic may be sufficient as the alkyl group of an alkyl (meth)acrylate monomer. For specific compounds belonging to linear alkyl (meth) acrylate monomers having C3 or more, if the presence of a branch is not specified, n-propyl (meth) acrylate, n-butyl (meth) acrylate, etc. are simply propyl ( It may be referred to as meth)acrylate, butyl (meth)acrylate, or the like.

In the above (A), as the branched alkyl acrylate monomer (a monomer containing a branched structure alkyl group), isopropyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-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, isopentadecyl (meth)acrylate, isohexadecyl (meth)acrylate and at least one or more of isoheptadecyl (meth) acrylate, isooctadecyl (meth) acrylate, isomyristyl (meth) acrylate, and isostearyl (meth) acrylate. Branched structure The alkyl group-containing monomer may have a branched structure (eg, two or more side chains relative to the main chain) having two or more alkyl groups, such as a t-butyl group.

In (A), as the cyclic alkyl acrylate monomer (alicyclic-containing monomer), cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, bicycloheptyl (meth) ) acrylate, bicyclooctyl (meth)acrylate, dimethylbicycloheptyl (meth)acrylate, and at least 1 or more types, such as dicyclopentanyl (meth)acrylate, are mentioned.

(A) A ratio of 50 parts by weight or more of an alkyl (meth)acrylate having C8 to C18 alkyl group in a total of 100 parts by weight of at least one or more kinds of alkyl (meth)acrylate monomers having C1-C18 alkyl groups It is preferable to be Among the C8-C18 alkyl (meth)acrylates in which the alkyl group has carbon atoms, branched alkyl group-containing monomers such as isooctyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferable.

In the above (B), the nitrogen-containing vinyl monomer includes at least one or more of a vinyl monomer containing an amide bond, a vinyl monomer containing an amino group, and a vinyl monomer having a nitrogen-containing heterocyclic structure. As a nitrogen-containing vinyl monomer, the thing which does not contain a hydroxyl group is preferable, and the thing which does not contain a hydroxyl group and a carboxyl group is more preferable. Examples of such monomers include the monomers exemplified above, for example, acrylic monomers containing N,N-dialkyl-substituted amino groups or N,N-dialkyl-substituted amide groups; N-vinyl-substituted lactams such as N-vinyl-2-pyrrolidone, N-vinylcaprolactam and N-vinyl-2-piperidone; N-(meth)acryloyl-substituted cyclic amines, such as N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine, are preferable.

Examples of the acrylic monomer containing an N,N-dialkyl-substituted amino group include dimethylaminomethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, and dimethylaminoisopropyl (meth)acrylate. Acrylate, dimethylaminobutyl (meth)acrylate, diethylaminomethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N-ethyl-N-methylaminoethyl (meth)acrylate, N-methyl dialkylamino (meth)acrylates such as -N-propylaminoethyl (meth)acrylate, N-methyl-N-isopropylaminoethyl (meth)acrylate, and dibutylaminoethyl (meth)acrylate; Dimethylaminopropyl (meth)acrylamide, diethylaminopropyl (meth)acrylamide, dipropylaminopropyl (meth)acrylamide, diisopropylaminopropyl (meth)acrylamide, N-ethyl-N-methylaminopropyl ( containing N,N-dialkyl-substituted aminoalkyl groups, such as meth)acrylamide, N-methyl-N-propylaminopropyl (meth)acrylamide, and N-methyl-N-isopropylaminopropyl (meth)acrylamide (meth)acrylamide etc. are mentioned.

Examples of the acrylic monomer containing an N,N-dialkyl-substituted amide group include dimethyl (meth)acrylamide, diethyl (meth)acrylamide, dipropylacrylamide, diisopropyl (meth)acrylamide, and dibutyl (meth)acrylamide. Dialkyl substitution (meth) such as acrylamide, N-ethyl-N-methyl (meth) acrylamide, N-methyl-N-propyl (meth) acrylamide, and N-methyl-N-isopropyl (meth) acrylamide Acrylamide etc. are mentioned.

Examples of N-vinyl-substituted lactams include N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, and N-vinyllauryllactam.

Examples of the N-vinyl-substituted heterocyclic vinyl compound include N-vinylpyridine, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxa. sol, N-vinylmorpholine, etc. are mentioned.

Examples of N-(meth)acryloyl-substituted cyclic amines include N-(meth)acryloylmorpholine, N-(meth)acryloylpiperazine, N-(meth)acryloylaziridine, N- (meth)acryloylazetidine, N-(meth)acryloylpyrrolidine, N-(meth)acryloylpiperidine, N-(meth)acryloylazepane, N-(meth)acryloyl Azokan etc. are mentioned.

Examples of other nitrogen-containing vinyl monomers include N-vinylcarboxylic acid amides such as N-vinylformamide, N-vinylacetamide, and N-vinyl-N-methylacetamide; Unsubstituted (meth)acrylamide, N-methyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-t-butyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N- (meth)acrylamides, such as oxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, and N,N- methylenebis (meth)acrylamide; unsaturated carboxylic acid imides such as N-cyclohexyl maleimide and N-phenyl maleimide; Unsaturated carboxylic acid nitriles, such as (meth)acrylonitrile, etc. are mentioned. It is preferable that the said nitrogen-containing vinyl monomer does not contain an isocyanate group. Further, it is preferable that the nitrogen-containing vinyl monomer does not contain a quaternary cation structure such as quaternary ammonium. The nitrogen-containing vinyl monomer may contain a tertiary cation structure in which the N,N-dialkyl-substituted amino group is neutralized to such an extent that it does not become acidic.

In said (B), as an alkoxy group containing alkyl (meth)acrylate monomer, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-propoxyethyl (meth)acryl Rate, 2-isopropoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-methoxypropyl (meth)acrylate, 2-ethoxypropyl (meth)acrylate, 2-pro Foxypropyl (meth) acrylate, 2-isopropoxypropyl (meth) acrylate, 2-butoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) Acrylate, 3-propoxypropyl (meth) acrylate, 3-isopropoxypropyl (meth) acrylate, 3-butoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4- At least one or more of ethoxybutyl (meth)acrylate, 4-propoxybutyl (meth)acrylate, 4-isopropoxybutyl (meth)acrylate, and 4-butoxybutyl (meth)acrylate can These alkoxy group containing alkyl (meth)acrylate monomers have a structure in which the atom of the alkyl group in the alkyl (meth)acrylate was substituted by the alkoxy group.

(B) nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acryl with respect to a total of 100 parts by weight of at least one or more kinds of alkyl (meth) acrylate monomers having C1 to C18 carbon atoms in the copolymer (A) It is preferable to copolymerize the total of at least 1 or more types of rate monomer in the ratio of 2.0-10 weight part, It is more preferable to copolymerize in the ratio of 2.0-9 weight part, It is especially copolymerized in the ratio of 2.5-9 weight part. desirable. You can also use together 1 type(s) or 2 or more types of a nitrogen containing vinyl monomer and an alkoxy group containing alkyl (meth)acrylate monomer, respectively.

The (C) polyalkylene glycol mono (meth) acrylate monomer is a mono (meth) acrylate monomer having a polyalkylene glycol chain, and among a plurality of hydroxyl groups of polyalkylene glycol, one hydroxyl group is (meth) What is necessary is just an esterified compound as an acrylic acid ester. Since the (meth)acrylic acid ester group becomes a polymerizable group, it can copolymerize with the said copolymer. The other hydroxyl group may be in a state of OH, and may be an alkyl ether such as methyl ether or ethyl ether, or a saturated carboxylic acid ester such as acetic acid ester.

In said (C), although an ethylene group, a propylene group, a butylene group etc. are mentioned as an alkylene group which polyalkylene glycol has, it is not limited to these. Polyalkylene glycol which has 2 or more types of alkylene groups in 1 molecule, such as polyethyleneglycol- polypropylene glycol, polyethyleneglycol- polybutylene glycol, polypropylene glycol- polybutylene glycol, may be sufficient as polyalkylene glycol.

Moreover, in said (C), it is preferable that the average repeating number of the alkylene oxide which comprises a polyalkylene glycol chain|strand is 4-14. Here, the "average number of repetitions of an alkylene oxide" is the average number of repetitions of an alkylene oxide unit in the "polyalkylene glycol chain" part.

As said (C), it is preferable that it is at least 1 or more types selected from 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, methoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth)acrylate, methoxypolybutylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, ethoxypolybutylene glycol (meth)acrylate and the like.

(C) polyalkylene glycol mono (meth) acrylate monomer with respect to a total of 100 parts by weight of at least one or more types of alkyl (meth) acrylate monomers having C1-C18 carbon atoms in the (A) alkyl group of the copolymer It is preferable to copolymerize 1 or more types of sum total in the ratio of 1.0-10 weight part, It is more preferable to copolymerize in the ratio of 1.5-9 weight part, It is especially preferable to copolymerize in the ratio of 2.0-9 weight part.

(D) Examples of the copolymerizable vinyl monomer having a hydroxyl group include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy Hydroxyl group-containing alkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide At least 1 type or more, such as hydroxyl-containing (meth)acrylamides, such as these are mentioned.

(D) the total of at least one copolymerizable vinyl monomer having a hydroxyl group with respect to 100 parts by weight of a total of at least one or more of the alkyl (meth)acrylate monomer having a C1-C18 alkyl group in the copolymer (A) It is preferable that it is copolymerizing in the ratio of 0.5-10 weight part, It is more preferable that it is copolymerizing in the ratio of 0.8-9 weight part, It is especially preferable that it is copolymerizing in the ratio of 0.8-8 weight part. When said (C) may have a hydroxyl group, it is preferable that said (D) does not have a polyalkylene glycol chain|strand.

The said copolymer may copolymerize the copolymerizable vinyl monomer which has an aromatic group in addition to at least 1 or more types of said (A)-(D). Examples of the copolymerizable vinyl monomer having an aromatic group include benzyl (meth) acrylate, naphthyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxybutyl (meth) acrylate, and 2-(1-naphthyl). Oxy) ethyl (meth) acrylate, 2- (2-naphthyloxy) ethyl (meth) acrylate, 6- (1-naphthyloxy) hexyl (meth) acrylate, 6- (2-naphthyloxy) (meth)acrylate monomers having an aromatic group such as hexyl (meth)acrylate, 8-(1-naphthyloxy)octyl (meth)acrylate, and 8-(2-naphthyloxy)octyl (meth)acrylate; and at least one or more of styrene-based monomers such as , styrene and methylstyrene. A copolymerizable vinyl monomer having no aromatic group may be sufficient as said (A)-(D).

The polymerization method of the said copolymer is not specifically limited, Well-known polymerization methods, such as a solution polymerization method and an emulsion polymerization method, can be used suitably. It is preferable that the said copolymer is an acrylic polymer containing 50 to 100 weight% of acrylic monomers, such as a (meth)acrylate monomer. It is preferable that the said copolymer is a copolymer with a weight average molecular weight of 200,000-1 million. It is preferable that the said copolymer is a copolymer which does not copolymerize the copolymerizable vinyl monomer which has a carboxyl group. In addition, from the viewpoint of suppressing the corrosiveness of the transparent conductive film to an adherend that is easily corroded, such as the ITO surface, by making the copolymer not copolymerized with a copolymerizable vinyl monomer having a carboxyl group, the acid value of the copolymer is set to 1.0 or less it is preferable

As said (E) thermal crosslinking agent, at least 1 or more types, such as an isocyanate type crosslinking agent, an epoxy type crosslinking agent, and an aluminum chelate type crosslinking agent, are mentioned.

Examples of the isocyanate-based crosslinking agent include bifunctional isocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), and xylylene diisocyanate (XDI). (diisocyanate compound) and trifunctional or more than trifunctional polyisocyanate compounds, such as these burette modified bodies, isocyanurate modified bodies, and an adduct body, are mentioned. Here, the adduct body of trivalent or more trivalent or more trivalent polyols, such as a diisocyanate compound and trimethylol propane and glycerol, is mentioned as an adduct body more than trifunctional. As said (E) thermal crosslinking agent, you may use only an isocyanate compound.

It is preferable that the said copolymer has a hydroxyl group as a functional group which can react with the said (E) thermal crosslinking agent, and it is especially preferable that it is formed by copolymerizing the said (D).

Moreover, it is preferable that the said adhesive composition for optics contains the said (E) thermal crosslinking agent in the ratio of 0.01-5 weight part with respect to 100 weight part of said (A).

As said (F), at least 1 or more types of the (meth)acrylate monomer which has a (meth)acryloyl group and an allyl ether group in 1 molecule is mentioned. Since the (meth)acryloyl group and the allyl ether group each have an ethylenically unsaturated group, said (F) has two or more ethylenically unsaturated groups. The number of (meth)acryloyl groups in (F) in one molecule is 1 or 2 or more, and the number of allyl ether groups in (F) in 1 molecule is 1 or 2 or more. Although the number of the (meth)acryloyl groups which said (F) has in 1 molecule and the number of allyl ether groups may differ, it is preferable that they are the same number.

Further, in the pressure-sensitive adhesive composition for optics according to the present embodiment, (F) has a function of remarkably improving the wet-heat durability of the pressure-sensitive adhesive layer. Although it is not clear why the wet-heat durability of the pressure-sensitive adhesive layer significantly increases when the above-mentioned (F) is contained in the pressure-sensitive adhesive composition for optics, the following is considered to be one of the reasons.

For this reason, in (F), (meth)acryloyl group and allyl ether group form a cyclic structure when crosslinking with the (H) photocrosslinking agent. And, when (F) is crosslinked by the (H) photocrosslinking agent, a polymer having a cyclic structure formed by a (meth)acryloyl group and an allyl ether group, and/or the cyclic structure is In the pressure-sensitive adhesive layer left to stand for a long time in a moist heat environment by crosslinking with the copolymer of the acrylic polymer, etc., moisture in the wet heat environment is trapped inside the cyclic structure, and then the pressure sensitive adhesive layer is placed in a room temperature environment (temperature 23). It is presumed that even when taken out under (°C x 50%RH), the free movement of water is prevented and foaming due to aggregation of water is suppressed.

For this reason, it is considered that the pressure-sensitive adhesive layer after crosslinking in two steps of crosslinking with the thermal crosslinking agent (E) followed by crosslinking with the above (H) photocrosslinking agent is provided with excellent moist heat durability. When the (F) is crosslinked with the (H) photocrosslinking agent to form the pressure sensitive adhesive layer, in order to form a cyclic structure, the pressure sensitive adhesive layer crosslinked with the (E) thermal crosslinking agent contains the above (F) And it is preferable that said (F) maintains the reactivity of two or more ethylenically unsaturated groups. For this reason, it is preferable that the said adhesive composition for optics does not contain a thermal-polymerization initiator at the time of bridge|crosslinking by the said (E) thermal crosslinking agent.

Moreover, as said (F), it is allyl ether group containing alkyl (meth)acrylate [CH ₂ =C(R ¹ ) COO-R ² -OCH ₂ CH=CH ₂ ; Here, R ¹ is a hydrogen atom or a methyl group, R ² is a divalent group such as an alkylene group], 2-(allyloxymethyl) acrylic acid alkyl ester [CH ₂ =CHCH ₂ OCH ₂ C(=CH ₂ )COOR; Here, R is an alkyl group] and the like. In particular, it is preferable that a 5-membered ring or 6-membered ring with high stability can be formed as a cyclic structure.

Specific examples of (F) include allyloxyethyl (meth)acrylate, allyloxypropyl (meth)acrylate, 2-(allyloxymethyl)methyl acrylate, 2-(allyloxymethyl)ethyl acrylate, 2- (allyloxymethyl) propyl acrylate, 2-(allyloxymethyl) butyl acrylate, 2-(allyloxymethyl) pentyl acrylate, 2-(allyloxymethyl) hexyl acrylate, etc. are mentioned.

Moreover, it is preferable that the said adhesive composition for optics contains the said (F) in the ratio of 0.1-10 weight part with respect to 100 weight part of said (A).

At least 1 type or more of the (meth)acrylate monomer which has two or more ethylenically unsaturated groups in 1 molecule which has an alkylene oxide group as said (G) is mentioned.

In addition, the said (G) should just be a compound in which two or more hydroxyl groups were esterified as (meth)acrylic acid ester among the several hydroxyl groups which alkylene glycol, polyalkylene glycol, etc. have, for example.

Moreover, in said (G), it is preferable that the average repeating number of the alkylene oxide which comprises polyalkylene glycol chain|strand is 4-14. Here, the "average number of repetitions of an alkylene oxide" is an average number of repetitions of an alkylene oxide unit in the "polyalkylene glycol chain" part. The average number of repetitions of the alkylene oxide of said (G) may be the same as or different from the average number of repetitions of the alkylene oxide of said (C).

In said (G), at least 1 or more types, such as an ethylene oxide group, a propylene oxide group, a butylene oxide group, are mentioned as said alkylene oxide group. The alkylene oxide group which said (G) has may be the same as or different from the alkylene oxide group which said (C) has. As a specific example of said (G), polyethyleneglycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, etc. are mentioned.

Moreover, it is preferable that the said adhesive composition for optics contains the said (G) in the ratio of 0.1-10 weight part with respect to 100 weight part of said (A).

As said (H) photocrosslinking agent, photoinitiators, such as a photoradical initiator, are mentioned, for example. After the optical pressure-sensitive adhesive composition is crosslinked with the thermal crosslinking agent (E), and then crosslinked with the (H) photocrosslinking agent to form a pressure-sensitive adhesive layer, even in the step (E) after crosslinking with the thermal crosslinking agent (E) H) It is preferable that the photocrosslinking agent maintains reactivity. Examples of the (H) photocrosslinking agent include acetophenone-based photocrosslinking agents, benzoin-based photocrosslinking agents, benzophenone-based photocrosslinking agents, thioxanthone-based photocrosslinking agents, and acylphosphine oxide-based photocrosslinking agents.

Moreover, it is preferable that the said adhesive composition for optics contains the said (H) photocrosslinking agent in the ratio of 0.01-5 weight part with respect to 100 weight part of said (A).

Examples of the acetophenone-based photocrosslinking agent include acetophenone, p-(tert-butyl)1',1',1'-trichloroacetophenone, chloroacetophenone, 2',2'-diethoxyacetophenone, hydroxylaceto phenone, 2,2-dimethoxy-2'-phenylacetophenone, 2-aminoacetophenone, dialkylaminoacetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and the like. have.

Benzoin-based photocrosslinking agents include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2- Methyl-1-phenyl-2-methylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, benzyldimethylketal, 2,2-dimethoxy- 1,2-diphenylethan-1-one and the like.

Benzophenone-based photocrosslinking agents include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, hydroxylbenzophenone, hydroxylpropylbenzophenone, acrylbenzophenone, 4,4 '-bis(dimethylamino)benzophenone etc. are mentioned.

Examples of the thioxanthone-based photocrosslinking agent include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, diethylthioxanthone, and dimethylthioxanthone.

Examples of the acylphosphine oxide-based photocrosslinking agent include (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

Other photocrosslinking agents include α-acyloxime ester, benzyl-(o-ethoxycarbonyl)-α-monoxime, phenylglyoxylic acid ester, 3-ketocoumarin, 2-ethylanthraquinone, camphorquinone, tetramethylthiuram sulfide, azobisisobutyronitrile, benzoyl peroxide, dialkyl peroxide, tert-butylperoxypivalate, and the like.

The optical pressure-sensitive adhesive composition is an optional component, and known additives such as antioxidants, surfactants, curing accelerators, plasticizers, fillers, crosslinking catalysts, crosslinking retarders, curing retarders, processing aids, and antioxidants can be appropriately blended. have. These additives may be used individually or in combination of 2 or more types.

After the pressure-sensitive adhesive layer of the present embodiment is applied to a substrate or a release film, the pressure-sensitive adhesive composition for optics is formed by crosslinking with the thermal crosslinking agent (E) and crosslinking with the (H) photocrosslinking agent, the pressure sensitive adhesive composition for optics It can be produced by crosslinking. In the pressure-sensitive adhesive layer of the present embodiment, after crosslinking with the thermal crosslinking agent (E), and before crosslinking with the photocrosslinking agent (H), the pressure sensitive adhesive layer (first step) has step followability and handling properties at the time of rework. great. In addition, the pressure-sensitive adhesive layer (second step) formed by crosslinking in two steps of (E) crosslinking with a thermal crosslinking agent and crosslinking with (H) a photocrosslinking agent is excellent in wet heat durability. The adhesive layer of this embodiment may bond a 1st-stage adhesive layer to a to-be-adhered body, and may bond a 2nd stage adhesive layer to a to-be-adhered body according to a use, objective, etc.

The pressure-sensitive adhesive layer of the first step contains the (H) photocrosslinking agent, so it is possible to crosslink it by the (H) photocrosslinking agent. When the 1st step adhesive layer is bonded to a to-be-adhered body, you may bridge|crosslink the adhesive layer in the state bonded to a to-be-adhered body with the said (H) photocrosslinking agent.

Examples of the energy rays irradiated when crosslinking with the (H) photocrosslinking agent include ultraviolet rays, electron beams, and in some cases, visible rays, but ultraviolet rays are preferably used from the viewpoint of simplicity. However, in this invention, it is not limited to an ultraviolet-ray. When irradiating with energy rays, the pressure-sensitive adhesive layer may be exposed, but if the release film or adherend laminated on the pressure-sensitive adhesive layer has energy ray permeability, it is preferable to irradiate the pressure-sensitive adhesive layer with energy rays through the release film or the adherend. do.

It is preferable that the adhesive composition for optics of this embodiment is excellent in the optical characteristic at the time of producing an adhesive layer. The optical pressure-sensitive adhesive composition is preferably transparent. It is preferable that the said additive does not impair transparency of the said adhesive layer in a function, quantity, etc. (non-coloring property). In addition, it is preferable that the pressure-sensitive adhesive layer (the first step pressure-sensitive adhesive layer or the second step pressure-sensitive adhesive layer) produced from the pressure-sensitive adhesive composition for optics is transparent.

Specifically, the total light transmittance of the pressure-sensitive adhesive layer having a thickness of 250 μm formed by crosslinking the optical pressure-sensitive adhesive composition in two steps of crosslinking with the (E) thermal crosslinking agent and crosslinking with the (H) photocrosslinking agent is 90 It is preferable that it is % or more, and it is more preferable that a total light transmittance is 91 % or more.

In addition, the haze value of the pressure-sensitive adhesive layer having a thickness of 250 μm formed by crosslinking the optical pressure-sensitive adhesive composition in two steps of crosslinking with the thermal crosslinking agent (E) followed by crosslinking with the photocrosslinking agent (H) is 1.0% or less. It is preferable, and it is more preferable that haze value is 0.6 % or less.

In addition, the pressure-sensitive adhesive layer having a thickness of 250 μm formed by crosslinking the optical pressure-sensitive adhesive composition in two steps of crosslinking with the (E) thermal crosslinking agent followed by crosslinking with the (H) photocrosslinking agent was formed at a temperature of 60° C. × relative humidity. After leaving it to stand in the atmosphere of 90 %RH for 240 hours, it is preferable that haze value at the time of taking out to room temperature environment (temperature 23 degreeC x 50 %RH) is 4.0 % or less, and it is more preferable that haze value is 3.5 % or less.

The pressure-sensitive adhesive layer after crosslinking by the thermal crosslinking agent (E) (before crosslinking by the (H) photocrosslinking agent) preferably has an adhesive force of 10N/25mm or less to soda glass. Thereby, the handling property at the time of the rework of an adhesive layer can be improved.

In addition, the pressure-sensitive adhesive layer crosslinked in two steps of (E) crosslinking by thermal crosslinking agent followed by (H) crosslinking by photocrosslinking agent preferably has an adhesive strength of 25N/25mm or more to soda glass. Even when the first-stage pressure-sensitive adhesive layer is bonded to the adherend and then crosslinked with the (H) photocrosslinking agent, high adhesive strength is obtained in the same manner as when the second-stage pressure-sensitive adhesive layer is prepared and bonded to the adherend. can

In the pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer crosslinked by the (E) thermal crosslinking agent is laminated on one side of a polyethylene phthalate resin film having a thickness of 188 μm, the pressure-sensitive adhesive film, When the adhesive layer with a thickness of 100 μm is interposed to glass having a printing step of a printed layer having a thickness of 42 μm, the followability to the printing step is good, and there is no foaming around the printing step. it is preferable

The adhesive film and adhesive sheet of this embodiment can be manufactured by forming the said adhesive layer on one side of a base material or a release film. On the other hand, in the 2015 edition of JIS Z0109 (Adhesive tape/adhesive sheet terminology), "adhesive sheet" is "a plate-shaped thing in which an adhesive layer is formed on one or both sides of a base material, and is a generic term for a thing to which a release liner is bonded." It is defined as "adhesive tape" defined as "a general term for forming an adhesive layer on one or both sides of a substrate and wound in a roll shape", but the adhesive film and adhesive sheet of this embodiment are limited to these it is not Although the thickness of the adhesive layer in the said adhesive film and an adhesive sheet is not specifically limited, For example, 10-3000 micrometers is preferable and 50-2000 micrometers is more preferable.

Resin films, such as a polyester film, etc. can be used as a base film used for formation of the said adhesive layer, and the release film (separator) which protects an adhesive surface.

The base film may be subjected to an antistatic treatment by application or mixing of an antistatic agent, antifouling treatment with a silicone-based or fluorine-based release agent or coating agent, silica fine particles, or the like on the surface opposite to the side on which the pressure-sensitive adhesive layer of the resin film is formed.

The release film is subjected to a release treatment with a silicone-based, fluorine-based mold release agent, or the like, on the surface of the pressure-sensitive adhesive layer to be combined with the pressure-sensitive adhesive surface. It can also be set as the adhesive sheet which consists of a structure of "release film/adhesive layer/release film" by putting together the surface to which the release process of the release film was respectively given to both surfaces of one adhesive layer. In this case, it becomes possible to bond optical members, such as an optical film, to to-be-adhered bodies, such as glass, by peeling the release film of both sides sequentially or simultaneously to expose an adhesive surface. As an optical film, a polarizing film, retardation film, an antireflection film, an anti-glare (anti-glare) film, an ultraviolet-ray absorption film, an infrared-absorbing film, an optical compensation film, a brightness improving film, etc. are mentioned.

Since the said adhesive layer can acquire favorable step|step difference followability|trackability also in bonding of glass and glass like a cover glass and a sensor glass, when bonding together the cover glass of a touchscreen and sensor glass, it can be used suitably. In addition, when bonding a film member and a glass member, the said adhesive film obtained by laminating|stacking the said adhesive layer on one side of a film member can also be bonded together to glass members, such as a cover glass and a sensor glass. The pressure-sensitive adhesive layer and the pressure-sensitive adhesive film are preferred as the pressure-sensitive adhesive layer for a touch panel and the pressure-sensitive adhesive film for a touch panel. As a film for touch panels in which the said adhesion film was used, the various optical films for touch panels mentioned later other than the adhesion film for touch panels, etc. are mentioned.

The pressure-sensitive adhesive film and the pressure-sensitive adhesive sheet can be used for bonding various optical films for peripheral members of liquid crystal display devices, mainly polarizing plates, various optical films for touch panels, various optical films for electronic paper, various optical films for organic EL, etc. .

Moreover, it can be set as the optical film in which the adhesive layer in which the said adhesive layer is laminated|stacked on at least one surface of these optical films was formed. Specifically, "optical film / adhesive layer / optical film", "optical film / adhesive layer / release film", "optical film / adhesive layer", "optical film / adhesive layer / optical film / adhesive layer / optical film" , "optical film/adhesive layer/optical film/adhesive layer/release film", "release film/adhesive layer/optical film/adhesive layer/release film", etc. are mentioned.

For example, if you have an adhesive layer protected with a release film, such as "optical film / adhesive layer / release film", peel the release film and expose the adhesive layer as in "optical film / adhesive layer", By bonding together with an optical film, the structure similar to "optical film/adhesive layer/optical film" in which an adhesive layer was used for bonding between layers is obtained.

The said adhesive film and adhesive sheet are used suitably for bonding of a polarizing plate and a display panel. As a display panel, a liquid crystal panel or organic electroluminescent panel is mentioned, for example. The pressure-sensitive adhesive film and the pressure-sensitive adhesive sheet can be preferably used as a pressure-sensitive adhesive layer of a polarizing plate having a pressure-sensitive adhesive layer formed thereon. As a constituent material of the polarizing plate, a retardation film having a retardation of λ/4 or λ/2 may be used. The said adhesive layer can be used for bonding of retardation film and a polarizing plate. According to the said adhesive film and adhesive sheet, since an adhesive layer has a low dielectric constant, the on-cell display apparatus in which the touch sensor was provided between a color filter and a polarizing plate WHEREIN: Bonding of the optical member in between a polarizing plate and a backlight unit. can be preferably used for In addition, the pressure-sensitive adhesive film and the pressure-sensitive adhesive sheet may be used for fixing optical components and electronic components included in various electronic devices.

Example

Hereinafter, the present invention will be described in detail with reference to Examples.

<Production 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 introduction tube, and the air in the reaction apparatus was replaced with nitrogen gas. Thereafter, 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, and polypropylene glycol monoacrylate (alkyl 60 parts by weight of a solvent (ethyl acetate) was added along with 4 parts by weight of renoxide average repetition number n=12) and 3.0 parts by weight of 6-hydroxyhexyl acrylate. Then, 0.1 weight part of azobisisobutyronitrile as a polymerization initiator was dripped over 2 hours, it was made to react at 65 degreeC for 6 hours, and the acrylic polymer solution used in Example 1 was obtained.

[Examples 2 to 5 and Comparative Examples 1 to 3]

Examples 2 to 5 and Comparative Examples 1 to 1 were carried out in the same manner as in the acrylic polymer solution used in Example 1, except that the monomer composition was as described in Groups (A) to (D) of Table 1, respectively. An acrylic polymer solution used in step 3 was obtained.

<Preparation of the pressure-sensitive adhesive composition, pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet>

[Example 1]

With respect to the acrylic polymer solution of Example 1 prepared as described above, 0.5 parts by weight of coronate HX, 5 parts by weight of 2-(allyloxymethyl)methyl acrylate, and polyethylene glycol diacrylate (average number of repetitions of alkylene oxide n= 4) 5 parts by weight and 0.5 parts by weight of a photocrosslinking agent (Omnirad (registered trademark) 184) were added and mixed with stirring to obtain the pressure-sensitive adhesive composition of Example 1. After applying the pressure-sensitive adhesive composition to the release film (1) (polyethylene terephthalate (PET) film with a thickness of 100 μm of the substrate coated with a silicone resin as a release agent layer) so that the thickness of the pressure-sensitive adhesive layer after drying becomes a predetermined value, After removing a solvent by drying at 90 degreeC, the adhesive layer which bridge|crosslinked the adhesive composition with the thermal crosslinking agent was formed by aging in 23 degreeC and atmosphere of 50 %RH for 7 days. Further, a release film (2) having a thickness of 75 µm on a substrate having a release agent layer having a peeling force lighter than that of the release film (1) is bonded to the surface of the pressure-sensitive adhesive layer, and a release film (1)/adhesive layer/ The adhesive sheet A of Example 1 comprised with the release film 2 (the 1st stage adhesive layer was formed) was obtained. After crosslinking with this thermal crosslinking agent, the pressure-sensitive adhesive layer was further irradiated with ultraviolet (UV) light and crosslinked with a photocrosslinking agent. Thereby, the pressure-sensitive adhesive sheet B of Example 1 in which the pressure-sensitive adhesive layer obtained by performing crosslinking by thermal crosslinking and crosslinking by light crosslinking in two steps is sandwiched by two release films (a second step pressure-sensitive adhesive layer is formed) got

[Examples 2 to 5 and Comparative Examples 1 to 3]

Except having made the composition of an additive as described in (E) group - (H) group of Table 1, respectively, it carried out similarly to the said adhesive sheet A-B of Example 1, Examples 2-5 and Comparative Examples 1 - 3 adhesive sheets A to B were obtained.

In Table 1, the numerical value of the weight part calculated|required by making the total of group (A) 100 weight part is shown. In addition, the compound name of the abbreviation of each component used in Table 1 is shown in Table 2. On the other hand, Coronate (registered trademark) is a trade name of Toso Corporation, Duranate (registered trademark) is a trade name of Asahi Kasei Corporation, and Omnirad (registered trademark) is a trade name of IGM Corporation. Omnirad 184 is a photocrosslinking agent based on 1-hydroxycyclohexylphenylketone. Omnirad 651 is a photocrosslinking agent based on 2,2-dimethoxy-2-phenylacetophenone. Omnirad TPO is a photocrosslinking agent based on (2,4,6-trimethylbenzoyl)diphenylphosphine oxide.

<Test method and evaluation>

From the pressure-sensitive adhesive sheets A to B in Examples 1 to 5 and Comparative Examples 1 to 3, if necessary, the release films (1) to (2) are peeled to expose the pressure-sensitive adhesive layer, and the following test method and measurement method evaluated by

On the other hand, about the adhesive sheets A-B in Examples 1-5 and Comparative Examples 1-3, in order to follow the following measuring method and test method, the thickness of an adhesive layer is different, and also the 1st stage adhesive layer The multiple types of adhesive sheet A with this formed, or the multiple types of adhesive sheet B with which the 2nd stage adhesive layer is formed was prepared. When testing the 1st stage adhesive layer, the adhesive sheet A was used. In addition, when testing the 2nd stage adhesive layer, the adhesive sheet B was used.

<Measuring method of total light transmittance>

Measurement method of light transmittance: According to JIS K7105, "Test method for optical properties of plastics", the total light transmittance (%) of the pressure-sensitive adhesive layer (second-stage pressure-sensitive adhesive layer) having a thickness of 250 µm was measured, and the "total light transmittance" of Table 3 ' did.

<Measuring method of haze value>

Measurement method of haze value: According to JIS K7136, "Method for obtaining haze of plastic-transparent material", the haze value (%) of the pressure-sensitive adhesive layer (2nd stage pressure-sensitive adhesive layer) having a thickness of 250 µm was measured, and shown in Table 3 It was set as "initial haze value". Furthermore, after leaving it to stand in the atmosphere of temperature 60 degreeC x 90 %RH for 240 hours, it took out to room temperature environment (23 degreeC, 50 %RH). 5 minutes after taking out, the haze value (%) was measured in the state which covered both surfaces of the said peeling film (1)-(2), and it was set as "haze value after moist heat" of Table 3.

<Evaluation of wet heat durability>

Evaluation of the wet-and-heat durability of the adhesive layer formed in the adhesive sheet B in Examples 1-5 and Comparative Examples 1-3 was performed using the "haze value after moist heat" measured by the measuring method of the said haze value. In addition, the judgment standard of moist heat durability was carried out as follows, and the evaluation result was made into "wet heat durability" of Table 3.

(circle): "haze value after moist heat" is 4.0 % or less.

(triangle|delta): "haze value after moist heat" is more than 4.0 % and 6.0 % or less.

x: "haze value after wet heat" is more than 6.0 %.

<Measuring method of adhesive force>

From the adhesive sheets A to B on one side of a polyester film having a thickness of 50 μm, a pressure-sensitive adhesive layer having a thickness of 175 μm (a first-stage pressure-sensitive adhesive layer or a second-stage pressure-sensitive adhesive layer) is transferred, and an adhesive film as a sample (adhesive) layered optical film) was obtained. Each of the obtained pressure-sensitive adhesive films was bonded to a non-tin-free surface of alkali-free glass washed with acetone with a pressing roll, autoclaved under the conditions of 50° C. and 0.5 MPa×20 minutes, and returned under an air atmosphere of 23° C.×50% RH, 1 hour passed. Then, the peel strength of the adhesive film was measured with a tensile tester in accordance with JIS Z0237 "Adhesive tape and adhesive sheet test method", and the peel strength when peeled at a rate of 300 mm/min in the 180 ° direction was measured, , was set as the adhesive force (N/25 mm) of the adhesive layer, respectively. In Table 3, the adhesive force measured using the pressure-sensitive adhesive layer in the first stage was defined as "adhesive force after thermal crosslinking", and the adhesive force measured using the pressure sensitive adhesive layer in the second stage was referred to as "adhesive force after photocrosslinking".

<Test method of step followability>

On one side of a polyethylene phthalate resin film having a thickness of 188 µm, from the pressure-sensitive adhesive sheet A, a pressure-sensitive adhesive layer (first stage pressure-sensitive adhesive layer) having a thickness of 100 µm, which is crosslinked by a thermal crosslinking agent, is transferred and bonded to form a sample An adhesion film was obtained. Thereafter, a cover glass having a thickness of 1.1 mm and having a printing step of a printed layer having a thickness of 42 μm was applied from above the pressure-sensitive adhesive layer (first-stage pressure-sensitive adhesive layer) to a vacuum bonding device under the conditions of a pressure of 80 kPa and a degree of vacuum of -100 kPa. was concatenated Furthermore, the level|step difference followability|trackability after autoclaving under the conditions of a temperature of 60 degreeC, 6 atmospheres, and 30 minutes was confirmed visually. The judgment criteria of visual confirmation were as follows, and the evaluation result was made into "step difference followability|trackability" of Table 3.

(circle): Follows the printing level difference, and there is no foaming around the printing level difference at all.

(triangle|delta): There is some foaming around the printing level|step difference.

x: There is foaming around the printing level difference.

In Table 3, the evaluation result of the adhesive sheets A-B of Examples 1-5 and the adhesive sheets A-B of Comparative Examples 1-3 is shown.

The pressure-sensitive adhesive sheet B of Examples 1 to 5 according to the present invention has a total light transmittance of 90% or more of an adhesive layer having a thickness of 250 μm after crosslinking in two steps of crosslinking with a thermal crosslinking agent followed by crosslinking with a photocrosslinking agent, and Even if the "initial haze value" is 1.0% or less, and the "haze value after moist heat" is 4.0% or less, even if the pressure-sensitive adhesive layer is left to stand in a moist heat environment for a long period of time and then taken out under a room temperature environment (temperature 23°C x 50%RH) , it was excellent in wet heat durability at the point which was excellent in an optical characteristic.

In addition, the pressure-sensitive adhesive films produced using the pressure-sensitive adhesive sheets A to B of Examples 1 to 5 according to the present invention have an adhesive force to soda glass of 10 N/25 mm or less after crosslinking with a thermal crosslinking agent, and additionally a thermal crosslinking agent 25N/25mm or more after crosslinking in two steps of crosslinking by means of a photocrosslinking agent. Therefore, the pressure-sensitive adhesive layer after crosslinking by the thermal crosslinking agent has excellent handling properties (easiness of peeling from the adherend) during rework, and the pressure sensitive adhesive after crosslinking in two steps: crosslinking with a thermal crosslinking agent followed by crosslinking with a photocrosslinking agent The layer had high adhesion.

In addition, the pressure-sensitive adhesive film produced using the pressure-sensitive adhesive sheet A of Examples 1 to 5 according to the present invention is the result of the step difference followability test when the pressure-sensitive adhesive layer (first-stage pressure-sensitive adhesive layer) having a thickness of 100 μm is formed. was followed by a printing step having a thickness of 42 μm, and there was no foaming around the printing step, and the step tracking property was also excellent.

That is, according to the pressure-sensitive adhesive sheets A to B of Examples 1 to 5 according to the present invention and the pressure-sensitive adhesive films produced using them, the subject of the present invention is the followability of the step to the step difference such as frame printing of the adherend, which is the subject of the present invention, and the rework time. A pressure-sensitive adhesive layer having good handling properties and excellent wet-heat durability could be achieved.

On the other hand, the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheets A to B of Comparative Example 1 is a copolymer obtained by copolymerizing two or more types of monomers, including the monomer of group (F) and crosslinking without the monomer of group (G). However, the adhesive sheet B of Comparative Example 1 had a low "haze value after moist heat" and was excellent in wet heat durability at the point with high transparency. In addition, the adhesive film produced using the adhesive sheet A of Comparative Example 1 had high "adhesive force after thermal crosslinking", poor reworkability, foaming around printing steps, and poor step followability.

In addition, the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheets A to B of Comparative Example 2 crosslinks the copolymer obtained by copolymerizing two or more types of monomers without containing the monomer of group (F) and containing the monomer of group (G). What was made and the adhesive sheet B of the comparative example 2 had high "haze value after moist heat", and since transparency was low, it was inferior to moist heat durability. Moreover, the "adhesive force after optical crosslinking" of the adhesive film produced using the adhesive sheet B of the comparative example 2 was very low. Moreover, the adhesive film produced using the adhesive sheet A of the comparative example 2 had foaming around the printing level difference, and it was inferior to step|step difference followability|trackability.

In addition, the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheets A to B of Comparative Example 3 is a copolymer obtained by copolymerizing two or more types of monomers, crosslinked by containing the monomers of (F) group and (G) group, or in Comparative Example 3 The adhesive sheet B had a low "haze value after moist heat" and was excellent in wet heat durability at the point with high transparency. In addition, the adhesive film produced using the adhesive sheet B of Comparative Example 3 had slightly low "adhesive force after photocrosslinking". Moreover, the adhesive film produced using the adhesive sheet A of the comparative example 3 had foaming around the printing level difference, and it was inferior to the level difference followability|trackability.

As described above, in the pressure-sensitive adhesive sheets A to B of Comparative Examples 1 to 3 and the pressure-sensitive adhesive films produced using them, the followability to steps to steps such as frame printing of the adherend, which is a subject of the present invention, and handling properties at the time of rework are good. Moreover, the adhesive layer which has the outstanding wet-heat durability was not able to be achieved.

In the adhesive sheet B of Comparative Examples 1 to 3, in the adhesive sheet B of Comparative Examples 1 and 3 in which the copolymer obtained by copolymerizing two or more types of monomers was crosslinked by containing the monomer of group (F), " The haze value after moist heat" was low, and the wet heat durability of the adhesive layer was excellent. However, in the adhesive sheet B of Comparative Example 2 in which the copolymer obtained by copolymerizing two or more monomers was crosslinked without containing the monomer of group (F), the "haze value after moist heat" was high, and the wet heat durability of the adhesive layer was It was poor. Therefore, in the optical pressure-sensitive adhesive composition according to the present invention, a useful component for obtaining a pressure-sensitive adhesive layer having excellent wet-heat durability is (F) having a (meth)acryloyl group and an allyl ether group in one molecule, and an ethylenically unsaturated group It was demonstrated that it is a (meth)acrylate monomer which has two or more.

Claims (5)

At least two or more selected from the group of compounds of a copolymerizable vinyl monomer having any one of an alkyl group, a hydroxyl group, and an aromatic group, and a nitrogen-containing vinyl monomer;
(C) a copolymer obtained by copolymerizing at least one of polyalkylene glycol mono (meth) acrylate monomers;
(F) a (meth)acrylate monomer having a (meth)acryloyl group and an allyl ether group in one molecule, and having two or more ethylenically unsaturated groups;
(G) a (meth)acrylate monomer having two or more ethylenically unsaturated groups in one molecule having an alkylene oxide group;
(E) a thermal crosslinking agent;
(H) An optical adhesive composition comprising a photocrosslinking agent. The method of claim 1,
The alkylene oxide of the (C) polyalkylene glycol mono (meth) acrylate monomer and/or the (G) alkylene oxide group in one molecule having two or more ethylenically unsaturated groups in the (meth) acrylate monomer The average number of repetitions is 4-14, The adhesive composition for optics characterized by the above-mentioned. On one side of the substrate, using the optical pressure-sensitive adhesive composition of claim 1 or 2, the pressure-sensitive adhesive layer formed by crosslinking with the (E) thermal crosslinking agent, or (E) following crosslinking with the thermal crosslinking agent, the above (E) H) A pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer crosslinked in two steps of crosslinking with a photocrosslinking agent is laminated. A pressure-sensitive adhesive sheet formed by using the pressure-sensitive adhesive composition for optics according to claim 1 or 2, wherein the pressure-sensitive adhesive layer crosslinked by the thermal crosslinking agent (E) is laminated between two release-treated release films. Using the optical pressure-sensitive adhesive composition of claim 1 or 2 on at least one side of the optical film, the pressure-sensitive adhesive layer formed by crosslinking with the (E) thermal crosslinking agent, or (E) following crosslinking with the thermal crosslinking agent (H) An optical film with a pressure-sensitive adhesive layer formed by laminating a pressure-sensitive adhesive layer crosslinked in two steps of crosslinking with a photocrosslinking agent.