CN111849361A - Adhesive composition for optics, and adhesive film and adhesive sheet using the same - Google Patents

Abstract

The present invention provides an optical adhesive composition capable of forming an adhesive layer having both step followability to step differences such as frame printing of an adherend, handling performance during rework, and excellent wet heat durability, and an adhesive composition using The adhesive film and the adhesive sheet of the adhesive composition for optics. The optical adhesive composition contains a copolymer obtained by copolymerizing at least two or more selected from the group consisting of a copolymerizable vinyl monomer and a nitrogen-containing vinyl monomer, the copolymerizable vinyl monomer It does not have a carboxyl group in the functional group, but has any one of an alkyl group, a hydroxyl group, an alkoxy group and an aromatic group; (F) has a (meth)acryloyl group and an allyl ether group in one molecule, and has two (G) Monomers of (meth)acrylates of (meth)acrylates having at least one ethylenically unsaturated group; A monomer; (E) a thermal crosslinker; and (H) a photocrosslinker.

Description

Adhesive composition for optics, and adhesive film and sheet using the same

technical field

The present invention relates to an optical adhesive composition, and an adhesive film and an adhesive sheet using the optical adhesive composition. In more detail, it relates to the provision of an adhesive capable of forming an adhesive that combines step followability to step differences such as frame printing of an adherend, handling performance during re-operation (easy peeling from an adherend), and excellent wet heat durability. The optical adhesive composition of the agent layer. Furthermore, it relates to providing the adhesive film and the adhesive sheet using this adhesive composition for optics.

In addition, the adhesive layer cross-linked with the thermal crosslinking agent using the optical adhesive composition of the present invention has the step followability of the step (unevenness) such as frame printing provided on the surface of the adherend, and rework good handling performance. Furthermore, the adhesive bond layer crosslinked through two stages of crosslinking by the thermal crosslinking agent and subsequent crosslinking by the photocrosslinking agent is excellent in wet heat durability.

Moreover, the adhesive composition for optics of this invention, and the adhesive film and adhesive sheet using this adhesive composition for optics can be used for the case where the optical film is bonded to various displays, and the optical films are bonded together to obtain a In the case of producing a laminated body of an optical film, and the case of fixing various optical components and electronic components mounted on electronic devices, etc.

In addition, in the present invention, the "damp heat durability" of the adhesive layer means that even if the adhesive layer is left in a humid heat environment for a long time and then taken out to a room temperature environment (temperature 23°C x 50% RH), it does not occur Visible foaming due to moisture and durability to maintain transparency.

Background technique

In recent years, electronic equipment combining a display (image display device) with a touch panel as an input device has been popularized. As a display (image display device) to which a touch panel is applied, a liquid crystal display (LCD), an electroluminescence display (inorganic EL, organic EL), etc. are mentioned. In addition, as a specific electronic device using a touch panel as an input device, a liquid crystal television, an inorganic EL television, an organic EL television, a mobile terminal, a mobile phone, an electronic paper, an electronic book terminal, a computer, etc. are mentioned.

In these electronic devices, the adhesive layer for bonding the optical member constituting the touch panel is required to have functions such as step followability and wet heat durability.

Conventionally, various proposals have been made in order to obtain an adhesive layer having step followability (Patent Documents 1 to 3). Moreover, the proposal for obtaining the adhesive bond layer which has step followability and wet heat durability is also proposed (patent document 4).

Patent Document 1 describes a method that, when a transparent panel and an image display device are fixed, has excellent adhesion to a step difference caused by a decorative portion provided on the surface of the transparent panel or the surface of the image display device, and can suppress the high temperature environment. A double-sided adhesive sheet with blisters and peeling in the step part.

In addition, Patent Document 2 describes a tape in which there are few bubbles at the edge of the printing due to the difference in printing steps when the adhesive layer is formed, no bubbles are generated when the adhesive is attached to the to-be-adhered body, and even if a load is applied, it is difficult to generate a dent. Surface protection film for decorative printed layers.

In addition, Patent Document 3 describes a photopolymerizable adhesive for use in a touch panel having a conductive film composed of a metal or a metal oxide, which is excellent in moisture-heat resistance stability and foaming resistance. A photopolymerizable adhesive that suppresses whitening and foaming, does not generate odor, and is not irritating to the skin, and is further non-corrosive to metals or metal oxides, and an adhesive sheet using the photopolymerizable adhesive.

In addition, Patent Document 4 describes an acrylic acid used in an adhesive composition for touch panels that is excellent in transparency, adhesiveness, durability, corrosion resistance, step followability, high dielectric constant, and coatability class of polymer compounds.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2012-211282

Patent Document 2: Japanese Patent Laid-Open No. 2015-221531

Patent Document 3: Japanese Patent Laid-Open No. 2013-256552

Patent Document 4: Japanese Patent Laid-Open No. 2012-041456

SUMMARY OF THE INVENTION

Technical problem to be solved by the present invention

The double-sided adhesive sheet described in Patent Document 1 satisfies the performance related to the print step followability because the value of the storage modulus of the adhesive layer is controlled within a specific numerical range to form a soft adhesive layer. However, if the adhesive force of the pressure-sensitive adhesive layer is increased, when the optical member is attached to the adherend and needs to be reattached, peeling may be difficult in some cases. )Difference. Conversely, when the handling performance at the time of rework of the adhesive layer is improved, the adhesive force after bonding the optical member to the adherend is too low, and peeling may occur. Therefore, the double-faced pressure-sensitive adhesive sheet described in Patent Document 1 has a problem in that it is difficult to achieve both the handling performance at the time of securing the pressure-sensitive adhesive layer and the improvement of the adhesive force after bonding the optical member to the adherend.

In addition, Patent Document 2 discloses that a decorative printing layer such as graphics and characters is formed on one side of a transparent resin film, and a photocurable resin composition containing a photopolymerization initiator and having fluidity is applied on a surface where the decoration is not formed. After the upper part of the part of the printing layer and the upper part of the decorative printing layer, UV irradiation was performed to form a photocured adhesive layer, and a surface protection film with a decorative printing layer was obtained. The surface protective film with a decorative printing layer of Patent Document 2 is coated with a photopolymerizable resin composition containing a photopolymerization initiator and has fluidity, and then UV-irradiated to form a photocured adhesive layer. Regardless of the flexibility of the UV-cured adhesive layer, the printing step difference can be embedded. However, since a liquid adhesive composition is applied, the adhesive layer of the invention of Patent Document 2 has a problem that it is difficult to form a thick adhesive layer. In addition, there is a technical problem that a liquid photocurable resin composition is applied to the part of the printing step to cover the printing step, and the operation is complicated.

In addition, Patent Document 3 discloses a photopolymerizable adhesive containing 40 to 92% by weight of (a-1) alkyl (meth)acrylate, 5 to 20% by weight of (a-2) Hydroxyl monomer, 3 to 25% by weight of (a-3) water-soluble N-substituted acrylamide, and monomer group (A) that does not substantially contain an acidic group-containing monomer relative to 100 parts by weight (total monomers body as 100% by weight) or its partial polymer (A'), containing 0.01 to 2 parts by weight of an isocyanate-based crosslinking agent and/or a multifunctional monomer (B) and 0.1 to 2 parts by weight of a photopolymerization initiator agent (C). If it is the photopolymerizable adhesive of patent document 3, the step followability and re-peelability are favorable. According to Examples 1 to 6 of Patent Document 3, a photopolymerizable adhesive was applied to a substrate to form a coating film with a thickness of 300 μm, and a PET film with a thickness of 25 μm that had undergone mold release treatment was coated with a mold release treatment surface. The surface of the coating film was placed in contact with the surface of the coating film, and photopolymerized by UV irradiation in a nitrogen atmosphere to produce an adhesive sheet. However, since the value of the adhesive force of the obtained adhesive sheet is in the range of 14 to 25 N/25 mm, it is difficult to peel off the adhesive sheet from the to-be-adhered body when re-adhering the adhesive sheet to the to-be-adhered body , there is a problem of poor processing performance during re-operation.

In addition, Patent Document 4 discloses an acrylic polymer compound for use in an adhesive composition for a touch panel obtained by copolymerizing a monomer component containing (a) having a carbon number (Meth)acrylate-based monomers having a hydrocarbon group of 1 to 12, (b) hydroxyl-containing (meth)acrylate-based monomers, (c) amide group-containing monomers, and (d) vinyl esters For the monomer, the polymer compound has a resin acid value of 0.1 mgKOH/g or less, a weight average molecular weight of 400,000 to 2 million, a Tg of -80 to 0°C, and a dielectric constant of 3 to 6. In the acrylic polymer compound of Patent Document 4, "preferably a hydroxyl-containing acrylate-based monomer is a cross-linked product obtained by cross-linking by imparting a functional group that can become a reactive site with a cross-linking agent to the polymer compound. For reasons such as imparting appropriate elasticity as an adhesive and improving cohesion, and at the same time increasing the dielectric constant, further contributing to the improvement of the heat-and-moisture resistance of the adhesive sheet, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularly preferred.” (Paragraph [0021] of Citation 4).

In addition, in the adhesive sheet of Patent Document 4, "in order to improve product design and achieve differentiation, a printing layer is often provided on a protective transparent plate. The substrate sheet or film often has this printing ink layer, which is used for each The level difference of about 10 to 30 μm, such as the layer of silver paste in the circuit and the level difference generated on the FPD part, has a problem that air bubbles are generated when the adhesive sheet is used for lamination. This is due to the lack of the level difference followability of the adhesive layer. Caused. This step followability is closely related to the appropriate Tg and gel fraction in the adhesive properties of the adhesive sheet obtained from the adhesive composition. The gel fraction of the adhesive is preferably about 30 to 70%, more preferably is about 40 to 65%” (paragraph [0081] of Citation 4).

However, in the adhesive sheets of Examples 1 to 12 of Citation 4, although the thickness of the adhesive layer of the adhesive sheets of Examples 1, 2, 5, 6, 8, and 10 was as thin as 50 μm, due to The haze value exceeds 4.0%, so there is a problem that it is necessary to further improve the heat and humidity resistance.

As described above, it is difficult to obtain an optical adhesive composition which can form an adhesive layer having excellent wet-heat durability and excellent handling performance during re-operation, which is capable of step-following to the step of the adherend such as frame printing, etc., by the prior art. , and an adhesive film and an adhesive sheet using the optical adhesive composition.

The present invention has been made in view of the above-mentioned problems, and its technical problem is to provide an adhesive which can form an adhesive that can form an adhesive that can have both step followability to step differences such as frame printing of an adherend, handling performance at the time of rework, and excellent wet heat durability. An optical adhesive composition for a layer, and an adhesive film and an adhesive sheet using the optical adhesive composition.

technical means to solve technical problems

The inventors of the present application have carefully studied the above-mentioned technical problems, and have found an adhesive layer ( The first stage) is excellent in step followability and handling performance during reoperation, and further, the optical crosslinking agent is made through two stages of crosslinking by the thermal crosslinking agent and subsequent crosslinking by the photocrosslinking agent. The adhesive layer (second stage) formed by crosslinking with the adhesive composition is excellent in wet heat durability, thereby completing the present invention. The optical adhesive composition contains: an acrylic polymer; a (meth)acrylic acid having a (meth)acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups A monomer of an ester; a monomer of a (meth)acrylate having an epoxy group and having two or more ethylenically unsaturated groups in one molecule; a thermal crosslinking agent; and a photocrosslinking agent.

The optical adhesive composition of the present invention is characterized in that it contains an acrylic polymer and has ( Monomers of (meth)acrylates having meth)acryloyl and allyl ether groups and having two or more ethylenically unsaturated groups, having epoxy alkyl groups and having two or more ethylenically unsaturated groups in one molecule The optical adhesive composition of a saturated group (meth)acrylate monomer, a thermal crosslinking agent, and a photocrosslinking agent is crosslinked, and an adhesive layer having different physical properties can be formed in two stages.

That is, the technical idea of the present invention is to provide an optical adhesive composition capable of forming an adhesive layer having different physical properties in two stages, and an adhesive film and an adhesive sheet using the optical adhesive composition, the Adhesive layers with different physical properties include the first-stage adhesive layer which is good in step followability to step differences such as frame printing of the adherend, and which has good handling performance during reoperation, and the first-stage adhesive layer which has excellent wet heat durability. Two-stage adhesive layer.

In order to solve the above-mentioned technical problem, the present invention provides an optical adhesive composition characterized by containing at least two selected from the group consisting of a copolymerizable vinyl monomer and a nitrogen-containing vinyl monomer. In the copolymer obtained by the above-mentioned copolymerization, the copolymerizable vinyl monomer does not have a carboxyl group in the functional group, but has any one of an alkyl group, a hydroxyl group, an alkoxy group and an aromatic group; (F) in one molecule Monomers of (meth)acrylates having (meth)acryloyl and allyl ether groups and having two or more ethylenically unsaturated groups; (G) having an epoxy group and having in one molecule A monomer of a (meth)acrylate of two or more ethylenically unsaturated groups; (E) a thermal crosslinking agent; and (H) a photocrosslinking agent.

Further, it is preferable that the copolymer is a copolymer having a weight average molecular weight of 200,000 to 1,000,000, which is composed of (methyl) having C1 to C18 carbon atoms with respect to the total of 100 parts by weight of the (A) alkyl group. At least one or more of the (B) nitrogen-containing vinyl monomers or alkoxy-containing (meth)acrylic acid alkyl ester monomers are copolymerized in an amount of 2.0 to 10 parts by weight. At least one or more of the (C) polyalkylene glycol mono(meth)acrylate monomers in a total of 1.0 to 10 parts by weight, and (D) having a hydroxyl group in a total of 0.5 to 10 parts by weight It is composed of at least one or more of the copolymerizable vinyl monomers; with respect to 100 parts by weight of the (A), the adhesive composition for optics contains the (E) in a ratio of 0.01 to 5 parts by weight A thermal crosslinking agent containing (F) (F) having a (meth)acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups in a ratio of 0.1 to 10 parts by weight. (G) a monomer of acrylic acid ester containing the (G) (meth)acrylic acid ester having an epoxy group and having two or more ethylenically unsaturated groups in one molecule in a ratio of 0.1 to 10 parts by weight The monomer contains the (H) photocrosslinking agent in a ratio of 0.01 to 5 parts by weight.

Moreover, it is preferable to crosslink the optical adhesive composition through two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent. The total light transmittance of the adhesive layer with a thickness of 250 μm formed together is 90% or more, and the haze value is 1.0% or less.

Moreover, it is preferable to crosslink the optical adhesive composition through two stages of crosslinking by the (E) thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent. The adhesive layer with a thickness of 250 μm was formed, and the adhesive layer was left for 240 hours in an atmosphere with a temperature of 60°C×90%RH, and then taken out to a room temperature environment (temperature 23°C×50%RH) Haze The value is 4.0% or less.

In addition, it is preferable that the copolymer is 50 parts by weight in at least one kind of (meth)acrylic acid alkyl ester monomers having a carbon number of C1 to C18 in the (A) alkyl group in a total of 100 parts by weight. The above ratios include (meth)acrylic acid alkyl esters having an alkyl group of C8 to C18 carbon atoms.

In addition, it is preferable that the copolymer is obtained by copolymerizing (C) a polyalkylene glycol mono(meth)acrylate monomer, and the optical adhesive composition contains (G) an epoxy group having an epoxy group in In the monomer of the (meth)acrylate having two or more ethylenically unsaturated groups in one molecule, it is preferable that the average number of repetitions of the alkylene oxides of the (C) and (G) is 4-14.

In addition, the present invention provides an adhesive film, which is formed by laminating an adhesive layer on one side of a base material, the adhesive layer using the above-mentioned optical adhesive composition and using the The (E) thermal cross-linking agent is cross-linked, or by using the above-mentioned optical adhesive composition, and through the cross-linking based on the (E) thermal cross-linking agent and the subsequent cross-linking based on the (H) optical adhesive The two-stage cross-linking of the cross-linking agent is formed by cross-linking; the adhesive force of the adhesive layer after cross-linking with the (E) thermal cross-linking agent to the soda-lime glass is below 10N/25mm, and further, through Adhesion of the adhesive layer to soda-lime glass after cross-linking in two stages of cross-linking by the (E) thermal cross-linking agent and subsequent cross-linking by the (H) optical cross-linking agent 25N/25mm or more.

In addition, the present invention provides an adhesive film, characterized in that it is formed by laminating an adhesive layer on one side of a polyethylene phthalate resin film having a thickness of 188 μm, the adhesive layer passing through The above-mentioned optical adhesive composition is used, and is cross-linked by the (E) thermal crosslinking agent; In the case of the glass with the printing step difference of the printing layer, the followability to the printing step difference is good, and there is no bubble at all around the printing step difference.

Moreover, this invention provides the film for touch panels using the said adhesive film.

Further, the present invention provides an adhesive sheet which has undergone a mold release treatment by laminating the adhesive layer cross-linked with the (E) thermal crosslinking agent using the above-mentioned optical adhesive composition on two sheets. between the release films.

Further, the present invention provides an optical film with an adhesive layer, which is obtained by laminating an adhesive layer on at least one surface of the optical film, the adhesive layer using the above-mentioned adhesive composition for optics and utilizing the above-mentioned adhesive composition for optics. The (E) thermal cross-linking agent is cross-linked, or by using the above-mentioned optical adhesive composition, and through the cross-linking based on the (E) thermal cross-linking agent and the subsequent cross-linking based on the (H) optical adhesive The cross-linking of the cross-linking agent is formed by the two-stage cross-linking.

Invention effect

The optical adhesive composition of the present invention is a (meth)acrylic acid containing an acrylic polymer, having a (meth)acryloyl group and an allyl ether group in one molecule, and having two or more ethylenically unsaturated groups Monomer of ester, monomer of (meth)acrylate having epoxy alkyl group and having two or more ethylenically unsaturated groups in one molecule, thermal crosslinking agent, and optical adhesive of photocrosslinking agent agent composition. Here, when a photocrosslinking agent is used, a mono (meth)acrylate having a (meth)acryloyl group and an allyl ether group in one molecule and having two or more ethylenically unsaturated groups Therefore, the adhesive layer after cross-linking in two stages of thermal cross-linking agent-based cross-linking and subsequent photo-cross-linking agent-based cross-linking has excellent moist heat durability. sex.

Moreover, in the adhesive film and the adhesive sheet of the present invention, an adhesive layer cross-linked using an optical adhesive composition comprising an acrylic polymer and having (methyl) in one molecule is formed. (meth)acrylate monomer of acryloyl group and allyl ether group and having two or more ethylenically unsaturated groups, having epoxy alkyl group and having two or more ethylenically unsaturated groups in one molecule group of (meth)acrylate monomers, thermal crosslinkers, and photocrosslinkers. The adhesive layer is an adhesive layer that is cross-linked with a thermal cross-linking agent and can be cross-linked in two stages of cross-linking based on a thermal cross-linking agent and subsequent cross-linking based on a photo-cross-linking agent, or It is an adhesive layer that has been cross-linked through two stages of thermal cross-linking agent-based cross-linking and subsequent photo-cross-linking agent-based cross-linking.

Therefore, according to the present invention, it is possible to provide an adhesive film and an adhesive sheet that have both step followability to step such as frame printing of an adherend, handling performance during rework, and excellent wet heat durability.

Detailed ways

Hereinafter, the present invention will be described based on suitable embodiments.

The optical adhesive composition of the present embodiment is characterized by containing a copolymer obtained by copolymerizing at least two or more selected from the group consisting of a copolymerizable vinyl monomer and a nitrogen-containing vinyl monomer, wherein the The copolymerizable vinyl monomer does not have a carboxyl group in the functional group, but has any one of an alkyl group, a hydroxyl group, an alkoxy group and an aromatic group; (F) has a (meth)acryloyl group and an allyl group in one molecule ether group and monomers of (meth)acrylates having two or more ethylenically unsaturated groups; (G) having epoxy alkyl groups and having two or more ethylenically unsaturated groups in one molecule ( meth)acrylate monomer; (E) thermal crosslinking agent; and (H) photocrosslinking agent.

In this specification, (meth)acrylate is a general term for acrylate and methacrylate. In addition, a (meth)acryloyl group is a general term for an acryloyl group and a methacryloyl group. The copolymer of the optical adhesive composition of the present embodiment is composed of, for example, at least one or more of (A) alkyl (meth)acrylate monomers having C1-C18 alkyl group carbon atoms, (B) At least one of nitrogen-containing vinyl monomers or alkoxy-containing alkyl (meth)acrylate monomers, and at least one of (C) polyalkylene glycol mono(meth)acrylate monomers A copolymer obtained by copolymerizing at least one type and (D) at least one type of copolymerizable vinyl monomer having a hydroxyl group.

Examples of the (A) alkyl (meth)acrylate monomer having a carbon number of C1 to C18 in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylate. ) propyl acrylate, butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, (meth)acrylic acid Nonyl ester, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, ten (meth)acrylate Among tetraalkyl esters, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, etc. at least one or more. The alkyl group of the (meth)acrylic acid alkyl ester monomer may be linear, branched, or cyclic. Regarding specific compounds belonging to the linear (meth)acrylic acid alkyl ester monomer having C3 or more carbon atoms, when the existence of a branch is not specified, n-propyl (meth)acrylate, ( N-butyl meth)acrylate and the like are abbreviated as propyl (meth)acrylate, butyl (meth)acrylate, and the like.

In the above (A), examples of branched alkyl acrylate monomers (monomers containing branched alkyl groups) include isopropyl (meth)acrylate and isobutyl (meth)acrylate. ester, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, Isononyl (meth)acrylate, isodecyl (meth)acrylate, isundecyl (meth)acrylate, isododecyl (meth)acrylate, isotridecyl (meth)acrylate Alkyl ester, isotetradecyl (meth)acrylate, isopentadecyl (meth)acrylate, isohexadecyl (meth)acrylate, isoheptadecyl (meth)acrylate At least one of esters, isostearyl (meth)acrylate, isomyristyl (meth)acrylate, isostearate (meth)acrylate, and the like. The branched-structure alkyl group-containing monomer may have a branched structure such as a t-butyl group having two or more alkyl groups (for example, two or more side chains on the main chain).

In the above (A), examples of the cyclic alkyl acrylate monomer (alicyclic-containing monomer) include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, ( Isobornyl meth)acrylate, dicycloheptyl (meth)acrylate, dicyclooctyl (meth)acrylate, dimethyldicycloheptyl (meth)acrylate, dicycloheptyl (meth)acrylate At least one of cyclopentyl esters and the like.

Among at least one of the (A) alkyl (meth)acrylate monomers in which the carbon number of the alkyl group is C1 to C18 in a total of 100 parts by weight, it is preferable that the carbon number of the alkyl group is C8 The ratio of the alkyl (meth)acrylate of -C18 is 50 weight part or more. Among the (meth)acrylic acid alkyl esters in which the number of carbon atoms in the alkyl group is C8 to C18, branched-chain structure-containing alkyl groups such as isooctyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred. 's monomer.

Examples of the nitrogen-containing vinyl monomer in (B) include amide bond-containing vinyl monomers, amino group-containing vinyl monomers, and vinyl monomers having a nitrogen-containing heterocyclic structure. at least one or more. As the nitrogen-containing vinyl monomer, a nitrogen-containing vinyl monomer not containing a hydroxyl group is preferable, and a nitrogen-containing vinyl monomer not containing a hydroxyl group and a carboxyl group is more preferable. As such monomers, the monomers exemplified above are preferred, such as acrylic monomers containing N,N-dialkyl-substituted amino groups or N,N-dialkyl-substituted amide groups; N-vinyl-2- N-vinyl substituted lactams such as pyrrolidone, N-vinyl caprolactam, N-vinyl-2-piperidone, etc.; N-(meth)acryloyl morpholine or N-(meth)acryloyl pyrrolidine, etc. N-(meth)acryloyl-substituted cyclic amines.

Examples of the acrylic monomer containing an N,N-dialkyl-substituted amino group include dimethylaminomethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and dimethylamino propyl (meth)acrylate, dimethylaminoisopropyl (meth)acrylate, dimethylaminobutyl (meth)acrylate, diethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate Ethylaminoethyl (meth)acrylate, N-ethyl-N-methylaminoethyl (meth)acrylate, N-methyl-N-propylaminoethyl (meth)acrylate, Dialkylamino (meth)acrylates such as N-methyl-N-isopropylaminoethyl (meth)acrylate, dibutylaminoethyl (meth)acrylate; dimethylaminopropyl (Meth)acrylamide, diethylaminopropyl (meth)acrylamide, dipropylaminopropyl (meth)acrylamide, diisopropylaminopropyl (meth)acrylamide, N-ethyl N-methylaminopropyl (meth)acrylamide, N-methyl-N-propylaminopropyl (meth)acrylamide, N-methyl-N-isopropylaminopropyl (meth)acrylamide (meth)acrylamide and the like containing N,N-dialkyl-substituted aminoalkyl groups.

Examples of the acrylic monomer containing an N,N-dialkyl-substituted amide group include dimethyl(meth)acrylamide, diethyl(meth)acrylamide, dipropylacrylamide, and diisopropylamide. (meth)acrylamide, dibutyl (meth)acrylamide, N-ethyl-N-methyl (meth)acrylamide, N-methyl-N-propyl (meth)acrylamide, Dialkyl-substituted (meth)acrylamides such as N-methyl-N-isopropyl (meth)acrylamide and the like.

As N-vinyl-substituted lactams, N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinyllaurolactam, etc. are mentioned.

Examples of the N-vinyl-substituted heterocyclic vinyl compound include N-vinylpyridine, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylpyrrole, N-vinylpyridine - Vinylimidazole, N-vinyloxazole, N-vinylmorpholine, etc.

Examples of N-(meth)acryloyl-substituted cyclic amines include N-(meth)acryloylmorpholine, N-(meth)acryloylpiperazine, and N-(meth)acryloylaziridine. pyridine, N-(meth)acryloyl azetidine, N-(meth)acryloyl pyrrolidine, N-(meth)acryloyl piperidine, N-(meth)acryloyl azetidine alkane, N-(meth)acryloyl azacyclooctane, etc.

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-tert-butyl (meth)acrylamide, N-methoxymethyl (Meth)acrylamide, N-ethoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, N,N-methylenebis(meth)acrylamide (meth)acrylamides such as acrylamide; unsaturated carboxylic acid imides such as N-cyclohexylmaleimide and N-phenylmaleimide; (meth)acrylonitrile, etc. Saturated carboxylic acid nitriles, etc. Preferably, the nitrogen-containing vinyl monomer does not contain an isocyanate group. In addition, it is preferable that the nitrogen-containing vinyl monomer does not contain a quaternary cationic structure such as a quaternary ammonium salt. The nitrogen-containing vinyl monomer may contain a tertiary cationic structure neutralized by an N,N-dialkyl-substituted amino group to such an extent that it does not become acidic.

Examples of the alkoxy-containing alkyl (meth)acrylate monomer in the (B) include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate base) acrylate, 2-propoxyethyl (meth)acrylate, 2-isopropoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2- Methoxypropyl (meth)acrylate, 2-ethoxypropyl (meth)acrylate, 2-propoxypropyl (meth)acrylate, 2-isopropoxypropyl (meth)acrylate base) acrylate, 2-butoxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylic acid, 3-ethoxypropyl (meth)acrylate, 3-propoxy propyl (meth)acrylate, 3-isopropoxypropyl (meth)acrylate, 3-butoxypropyl (meth)acrylate, 4-methoxybutyl (methyl) Acrylates, 4-ethoxybutyl (meth)acrylate, 4-propoxybutyl (meth)acrylate, 4-isopropoxybutyl (meth)acrylate, 4-butoxy At least one or more of butyl (meth)acrylate and the like. These alkoxy group-containing alkyl (meth)acrylate monomers have a structure in which the atom of the alkyl group in the alkyl (meth)acrylate is substituted with an alkoxy group.

In the copolymer, at least one or more of the C1-C18 alkyl (meth)acrylate monomers with respect to the total of 100 parts by weight of the (A) alkyl group is preferably 2.0 in total. (B) The nitrogen-containing vinyl monomer or the alkoxy-containing (methyl group) is copolymerized in a ratio of to 10 parts by weight, more preferably in a ratio of 2.0 to 9 parts by weight in total, particularly preferably in a ratio of 2.5 to 9 parts by weight in total. group) at least one or more of alkyl acrylate monomers. A nitrogen-containing vinyl monomer and an alkoxy group-containing alkyl (meth)acrylate monomer can be used individually by 1 type or in combination of 2 or more types.

The (C) polyalkylene glycol mono(meth)acrylate monomer is a mono(meth)acrylate monomer having a polyalkylene glycol chain and is derived from polyalkylene glycol. A compound in which one of the plurality of hydroxyl groups possessed is esterified into a (meth)acrylate may be sufficient. Since the (meth)acrylate group is a polymerizable group, it can be copolymerized with the copolymer. Other hydroxyl groups may remain OH, or may be alkyl ethers such as methyl ether or ethyl ether, or saturated carboxylic acid esters such as acetate.

Although an ethylene group, a propylene group, a butylene group, etc. are mentioned as an alkylene group which polyalkylene glycol has in said (C), it is not limited to these. The polyalkylene glycol may be a polyalkylene group having two or more types of alkylene groups in one molecule, such as polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, and the like glycol.

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

The (C) is preferably selected from polyalkylene glycol mono(meth)acrylate, methoxypolyalkylene glycol (meth)acrylate, ethoxypolyalkylene glycol ( At least one or more of meth)acrylates. More specifically, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polybutylene glycol mono(meth)acrylate, methoxypolyethylene glycol ( Meth)acrylate, Methoxypolypropylene glycol (meth)acrylate, Methoxypolybutylene glycol (meth)acrylate, Ethoxypolyethylene glycol (meth)acrylate, Ethoxypolyethylene glycol (meth)acrylate Propylene glycol (meth)acrylate, ethoxylated polybutylene glycol (meth)acrylate, etc.

In the copolymer, at least one or more of the C1-C18 alkyl (meth)acrylate monomers with respect to the total of 100 parts by weight of the (A) alkyl group is preferably 1.0 in total. (C) polyalkylene glycol mono(meth)acrylate monopoly(C) is copolymerized in a ratio of to 10 parts by weight, more preferably in a ratio of 1.5 to 9 parts by weight in total, particularly preferably in a ratio of 2.0 to 9 parts by weight in total At least one or more in the body.

Examples of the (D) copolymerizable vinyl monomer having a hydroxyl group include 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Hydroxy-containing (meth)acrylic acid alkyl esters such as 2-hydroxyethyl (meth)acrylate, and N-hydroxy (meth)acrylamide, N-methylol (meth)acrylamide, N -At least one kind or more of hydroxyl group-containing (meth)acrylamides such as hydroxyethyl (meth)acrylamide.

In the copolymer, at least one or more of the C1-C18 alkyl (meth)acrylate monomers with respect to the total of 100 parts by weight of the (A) alkyl group is preferably 0.5 in total. At least one of (D) the copolymerizable vinyl monomer having a hydroxyl group is copolymerized in a ratio of to 10 parts by weight, more preferably in a ratio of 0.8 to 9 parts by weight in total, particularly preferably in a ratio of 0.8 to 8 parts by weight in total above. When the (C) may have a hydroxyl group, it is preferable that the (D) does not have a polyalkylene glycol chain.

In the copolymer, in addition to at least one or more of the above (A) to (D), a copolymerizable vinyl monomer having an aromatic group may be copolymerized. Examples of the copolymerizable vinyl monomer having an aromatic group include benzyl (meth)acrylate, naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxy (meth)acrylate Butyl ester, 2-(1-naphthoxy)ethyl (meth)acrylate, 2-(2-naphthoxy)ethyl (meth)acrylate, 6-(1-naphthoxy)hexyl ( Meth)acrylate, 6-(2-naphthyloxy)hexyl(meth)acrylate, 8-(1-naphthyloxy)octyl(meth)acrylate, 8-(2-naphthyloxy) At least one or more of (meth)acrylate monomers having an aromatic group such as octyl (meth)acrylate, and styrene-based monomers such as styrene and methylstyrene. The said (A)-(D) may be a copolymerizable vinyl monomer which does not have an aromatic group.

The polymerization method of the copolymer is not particularly limited, and suitable and well-known polymerization methods such as solution polymerization method and emulsion polymerization method can be used. The copolymer is preferably an acrylic polymer containing 50 to 100% by weight of acrylic monomers such as (meth)acrylate monomers. Preferably, the copolymer is a copolymer having a weight average molecular weight of 200,000 to 1,000,000. Preferably, the copolymer is a copolymer in which a copolymerizable vinyl monomer having a carboxyl group is not copolymerized. In addition, from the viewpoint of suppressing the corrosiveness of the ITO surface of the transparent conductive film, etc. to the adherend which is easily corroded, it is preferable to use a copolymer in which a copolymerizable vinyl monomer having a carboxyl group is not copolymerized. The acid value of the said copolymer shall be 1.0 or less.

As said (E) thermal crosslinking agent, at least 1 type or more of an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an aluminum chelate type crosslinking agent, etc. are mentioned.

Examples of the isocyanate-based crosslinking agent include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), and xylylene diisocyanate. Difunctional isocyanates (diisocyanate compounds) such as diisocyanate (XDI), or their biuret modifications, isocyanurate modifications, adducts and other trifunctional or higher polyisocyanate compounds (polyisocyanate) . Here, the adduct of tri- or higher-functionality includes an adduct of a diisocyanate compound and a tri- or higher-valent polyhydric alcohol such as trimethylolpropane and glycerin. As the (E) thermal crosslinking agent, only an isocyanate compound may be used.

The copolymer preferably has a hydroxyl group as a functional group reactive with the (E) thermal crosslinking agent, and particularly preferably the (D) is copolymerized.

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 type or more of the monomer of the (meth)acrylate which has a (meth)acryloyl group and an allyl ether group in one molecule is mentioned. Since the (meth)acryloyl group and the allyl ether group each have an ethylenically unsaturated group, the (F) has two or more ethylenically unsaturated groups. The number of (meth)acryloyl groups contained in the (F) molecule is 1 or 2 or more, and the number of allyl ether groups contained in the (F) molecule is 1 or 2 or more. The number of the (meth)acryloyl group and the number of the allyl ether group which the (F) has in one molecule may be different, but the same number is preferable.

Moreover, in the adhesive composition for optics of this embodiment, the said (F) has the function of remarkably improving the wet heat durability of the adhesive layer. The reason why the wet-heat durability of the adhesive layer is remarkably improved when the optical adhesive composition contains the above-mentioned (F) is not clear, but one of the reasons is thought to be as follows.

The reason for this is that when the (F) is cross-linked by the (H) photo-crosslinking agent, the (meth)acryloyl group and the allyl ether group form a cyclic structure. Furthermore, when the (F) is cross-linked by the (H) photo-crosslinking agent, a polymer having a cyclic structure composed of a (meth)acryloyl group and an allyl ether group is formed, And/or, the cyclic structure and the copolymer of the acrylic polymer are cross-linked, etc., so that in the adhesive layer placed in a humid and hot environment for a long time, the moisture in the humid and hot environment is trapped in the cyclic structure. Inside the structure, even after the adhesive layer is taken out to a room temperature environment (temperature 23°C x 50% RH), free movement of moisture is prevented and blistering caused by moisture aggregation is suppressed.

For the above-mentioned reasons, it is considered that the adhesive layer that has been cross-linked through two stages of cross-linking by the (E) thermal cross-linking agent and subsequent cross-linking by the (H) photo-cross-linking agent has Excellent damp heat durability. When forming an adhesive layer by crosslinking the (F) with the (H) photocrosslinking agent, in order to form a cyclic structure, an adhesive crosslinked with the (E) thermal crosslinking agent is preferable The layer contains the (F), and the (F) maintains the reactivity of the two or more ethylenically unsaturated groups. Therefore, when crosslinking with the (E) thermal crosslinking agent, it is preferable that the optical adhesive composition does not contain a thermal polymerization initiator.

Moreover, as said (F), allyl ether group-containing alkyl (meth)acrylate [CH ₂ =C(R ¹ )COO-R ² -OCH ₂ CH=CH ₂ ; here is exemplified , R ¹ is a hydrogen atom or a methyl group, R ² is a divalent group such as an alkylene group], 2-(allyloxymethyl) acrylate [CH ₂ =CHCH ₂ OCH ₂ C(=CH ₂ ) COOR; where R is alkyl] etc. As the cyclic structure, a five-membered ring or a six-membered ring capable of forming high stability is particularly preferable.

Specific examples of the (F) include allyloxyethyl (meth)acrylate, allyloxypropyl (meth)acrylate, and 2-(allyloxymeth)acrylic acid. methyl ester, ethyl 2-(allyloxymeth)acrylate, propyl 2-(allyloxymeth)acrylate, butyl 2-(allyloxymeth)acrylate, 2-(allyl) oxymethyl) pentyl acrylate, 2-(allyloxymeth) hexyl acrylate, and the like.

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).

As said (G), at least 1 type or more of the monomer of the (meth)acrylate which has an epoxy group and has two or more ethylenically unsaturated groups in one molecule is mentioned.

Further, the (G) may be, for example, a compound obtained by esterifying two or more hydroxyl groups among a plurality of hydroxyl groups included in an alkylene glycol, a polyalkylene glycol, or the like into a (meth)acrylate. That's it.

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

In said (G), as said alkylene oxide group, at least 1 type or more of an ethylene oxide group, a propylene oxide group, a butylene oxide group, etc. are mentioned. The alkylene oxide which the said (G) has may be the same as or different from the alkylene oxide which the said (C) has. Specific examples of the (G) include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, and the like.

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. In order to form an adhesive layer by crosslinking the optical adhesive composition with the (E) thermal crosslinking agent and then crosslinking it with the (H) photocrosslinking agent, the (H) photo-crosslinking agent is preferably used. H) The photo-crosslinking agent maintains reactivity even in the stage after the cross-linking with the (E) thermal cross-linking agent. Examples of such (H) photocrosslinking agents include acetophenone-based photocrosslinking agents, benzoin-based photocrosslinking agents, benzophenone-based photocrosslinking agents, and thioxanthone-based photocrosslinking agents. agent, acylphosphine oxide photocrosslinking agent, etc.

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'-dichloroacetophenone Ethoxyacetophenone, hydroxyacetophenone, 2,2-dimethoxy-2'-phenylacetophenone, 2-aminoacetophenone, dialkylaminoacetophenone, 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one, etc.

Examples of the benzoin-based photocrosslinking agent include benzil, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 1-hydroxy ring Hexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-2-methylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane -1-one, benzoin dimethyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, etc.

Examples of the benzophenone-based photocrosslinking agent include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, methyl phthaloyl benzoate, and 4-phenyldiphenyl Ketone, hydroxybenzophenone, hydroxypropyl benzophenone, acrylic benzophenone, 4,4'-bis(dimethylamino)benzophenone, etc.

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, phenylbis(2,4,6-trimethylbenzoyl) Phosphine oxide, etc.

Examples of other photocrosslinking agents include α-acyl oxime ester, benzyl-(o-ethoxycarbonyl)-α-monoxime, benzoyl formate, 3-coumarin ketone, 2-ethyl acetate Anthraquinone, camphorquinone, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzoyl peroxide, dialkyl peroxide, tert-butyl peroxypivalate, etc.

Antioxidants, surfactants, curing accelerators, plasticizers, fillers, crosslinking catalysts, crosslinking retarders, curing retarders, processing aids, A well-known additive, such as an aging agent, is used as an arbitrary component. These additives can be used alone or in combination of two or more.

The pressure-sensitive adhesive layer of the present embodiment can be obtained by applying the pressure-sensitive adhesive composition for optics to a substrate or a release film, and then performing cross-linking by the (E) thermal cross-linking agent with the (H) The photo-crosslinking agent crosslinks the adhesive composition for optics and produces it. The pressure-sensitive adhesive layer of the present embodiment follows the step of the pressure-sensitive adhesive layer (first stage) after being cross-linked by the (E) thermal cross-linking agent and before being cross-linked by the (H) photo-cross-linking agent. Excellent performance in handling and reprocessing. Further, the adhesive layer (second stage) cross-linked by the two-stage cross-linking by the (E) thermal cross-linking agent and the subsequent cross-linking by the (H) photo-cross-linking agent Excellent wet heat durability. In the adhesive layer of the present embodiment, the first-stage adhesive layer may be bonded to the adherend, and the second-stage adhesive layer may be bonded to the to-be-adhered body, depending on the application, purpose, and the like.

The adhesive layer of the first stage contains the (H) photo-crosslinking agent, and can be cross-linked by the (H) photo-crosslinking agent. When the adhesive layer of the first stage is bonded to an adherend, the (H) photocrosslinking agent may be used to crosslink the adhesive layer in the state of being bonded to the adherend.

Examples of energy rays to be irradiated during crosslinking by the (H) photocrosslinking agent include ultraviolet rays, electron beams, and optionally visible light. In terms of simplicity, ultraviolet rays are preferably used. However, in the present invention, it is not limited to ultraviolet rays. When irradiating the energy ray, the adhesive layer may be exposed, but if the release film or the adherend laminated on the adhesive layer is transparent to the energy ray, the adhesive layer is preferably exposed through the release film or the adherend. Irradiation of energy rays is performed.

Preferably, the optical adhesive composition of the present embodiment is excellent in optical properties when used as an adhesive layer. The optical adhesive composition is preferably transparent. It is preferable that the function, amount, etc. of the additive do not impair the transparency (non-coloring property) of the adhesive layer. Moreover, it is preferable that the adhesive bond layer (1st-stage adhesive bond layer or 2nd-stage adhesive bond layer) produced from the said adhesive composition for optics is transparent.

Specifically, the optical adhesive composition is cross-linked through two stages of cross-linking by the (E) thermal cross-linking agent and subsequent cross-linking by the (H) photo-cross-linking agent. It is preferable that the total light transmittance of the 250-micrometer-thick adhesive bond layer formed together is 90% or more, and it is more preferable that the total light transmittance is 91% or more.

In addition, the optical adhesive composition is cross-linked through two stages of cross-linking by the (E) thermal cross-linking agent and subsequent cross-linking by the (H) photo-cross-linking agent, whereby the optical adhesive composition is cross-linked. The haze value of the formed adhesive layer having a thickness of 250 μm is preferably 1.0% or less, and more preferably 0.6% or less.

In addition, the optical adhesive composition is cross-linked through two stages of cross-linking by the (E) thermal cross-linking agent and subsequent cross-linking by the (H) photo-cross-linking agent, whereby the optical adhesive composition is cross-linked. An adhesive layer with a thickness of 250 μm was formed, and the adhesive layer was left for 240 hours in an atmosphere of temperature 60°C×relative humidity 90%RH, and then taken out to room temperature (temperature 23°C×50%RH) Haze value It is preferably 4.0% or less, and the haze value is more preferably 3.5% or less.

The adhesive force to soda lime glass of the adhesive layer after crosslinking with the (E) thermal crosslinking agent (before crosslinking with the (H) photocrosslinking agent) is preferably 10 N/25 mm or less. Thereby, the handling performance at the time of rework of an adhesive bond layer can be improved.

Further, the adhesion to soda lime glass of the adhesive layer cross-linked through two stages of cross-linking by the (E) thermal cross-linking agent and subsequent cross-linking by the (H) photo-cross-linking agent Preferably it is 25N/25mm or more. When the first-stage adhesive layer is bonded to the adherend and then cross-linked with the (H) photo-crosslinking agent, the second-stage adhesive layer can also be produced and then bonded to the adherend. In the same way, high adhesion is obtained.

The adhesive film in which the adhesive layer was laminated on one side of a polyethylene phthalate resin film having a thickness of 188 μm was pasted via the adhesive layer having a thickness of 100 μm. When it is suitable for the glass which has the printing level difference of the printing layer with a thickness of 42 micrometers, it is preferable that the followability to the printing level difference is good, and there is no bubble at all around the printing level difference. The pressure-sensitive adhesive layer is formed by cross-linking with the (E) thermal cross-linking agent using the optical pressure-sensitive adhesive composition.

The pressure-sensitive adhesive film and pressure-sensitive adhesive sheet of the present embodiment can be produced by forming the pressure-sensitive adhesive layer on one surface of a base material or a release film. In addition, in the 2015 edition of JIS Z0109 (Terminology of Adhesive Tape and Adhesive Sheet), "adhesive sheet" is defined as "a sheet having an adhesive layer provided on one side or both sides of a substrate, a plate-like sheet, and a "A general term for articles with release liners", which is distinguished from "adhesive tapes" defined as "a general term for articles in which an adhesive layer is provided on one or both sides of a substrate and is wound into a roll shape", but The adhesive film and the adhesive sheet of this embodiment are not limited to this. Although the thickness of the adhesive bond 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 bond layer, or a release film (separation film) which protects an adhesive surface.

In the base film, the surface of the resin film opposite to the side on which the adhesive layer is formed can be subjected to antifouling treatment using silicone-based, fluorine-based mold release agents or coating agents, silica fine particles, or the like, based on Antistatic treatment such as coating or kneading of antistatic agent.

In the mold release film, mold release treatment can be performed on the surface on the side to which the adhesive surface of the adhesive layer is bonded with a silicone-based, fluorine-based mold release agent, or the like. An adhesive sheet having a configuration of "release film/adhesive layer/release film" can also be obtained by sticking the release-treated surface of the release film to both sides of one adhesive layer, respectively. At this time, by peeling off the release film of both sides sequentially or simultaneously, and exposing the adhesive surface, optical members, such as an optical film, can be bonded to to-be-adhered bodies, such as glass. As an optical film, a polarizing film, a retardation film, an antireflection film, an anti-glare film, an ultraviolet absorption film, an infrared absorption film, an optical compensation film, a brightness improvement film, etc. are mentioned.

Since the adhesive layer can obtain good step followability even in lamination of glass such as cover glass and sensor glass, it is possible to attach a cover plate of a touch panel to a touch panel. Use it appropriately for glass and sensor glass. Moreover, 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 to glass members, such as a cover glass and a sensor glass. The adhesive layer and the adhesive film are suitable as the adhesive layer for touch panels and the adhesive film for touch panels. As a film for touch panels using the said adhesive film, in addition to the adhesive film for touch panels, various optical films for touch panels etc. which are mentioned later are mentioned.

The adhesive film and the adhesive sheet can be used to bond various optical films for peripheral members of liquid crystal display devices including polarizers, various optical films for touch panels, and various optical films for electronic paper , Various optical films for organic EL, etc.

Moreover, the optical film with an adhesive bond layer which laminated|stacked the said adhesive bond layer on at least one surface of these optical films can be used. Specifically, "optical film/adhesive layer/optical film", "optical film/adhesive layer/release film", "optical film/adhesive layer", "optical film/adhesive layer/optical film" 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. composition.

For example, when there is a pressure-sensitive adhesive layer protected by a release film as in "optical film/adhesive layer/release film", by peeling the release film, the pressure-sensitive adhesive is applied in the form of "optical film/adhesive layer" The layer is exposed and bonded to another optical film to obtain a configuration of "optical film/adhesive layer/optical film" in which the adhesive layer is used for interlayer bonding.

The adhesive film and the adhesive sheet are suitable for bonding a polarizer and a display panel. As a display panel, a liquid crystal panel or an organic electroluminescent panel is mentioned, for example. The pressure-sensitive adhesive film and the pressure-sensitive adhesive sheet can be suitably used as the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached polarizing plate. As a constituent material of the polarizer, a retardation film having a retardation of λ/4 or λ/2 can also be used. When bonding a retardation film and a polarizing plate, the said adhesive bond layer can be used. According to the above-mentioned adhesive film and adhesive sheet, since the dielectric constant of the adhesive layer is low, it can be suitably used for an on-cell display device in which a touch sensor is provided between a color filter and a polarizer. Bonding of the optical member between the polarizer and the backlight unit. In addition, the above-mentioned adhesive film and adhesive sheet can be used when fixing optical components and electronic components attached to various electronic devices.

Example

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

<Preparation of acrylic polymer>

[Example 1]

Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction pipe, and the air in the reaction apparatus was replaced with nitrogen gas. Then, 70 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of ethyl acrylate, 20 parts by weight of isobornyl acrylate, 5 parts by weight of N-vinylpyrrolidone, 4 parts by weight of Polypropylene glycol monoacrylate (average number of repetitions of alkylene oxide n=12), 3.0 parts by weight of 6-hydroxyhexyl acrylate, and 60 parts by weight of a solvent (ethyl acetate). Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and the mixture was reacted at 65° C. for 6 hours to obtain the acrylic polymer solution used in Example 1.

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

Examples 2 to 5 were obtained in the same manner as the acrylic polymer solution used in the above-mentioned Example 1, except that the compositions of the monomers were as shown in the descriptions of the groups (A) to (D) in Table 1, respectively. and the acrylic polymer solutions used in Comparative Examples 1 to 3.

<Preparation of an adhesive composition, an adhesive layer, and an adhesive sheet>

[Example 1]

To the acrylic polymer solution of Example 1 prepared in the above-described manner, 0.5 parts by weight of CORONATE HX, 5 parts by weight of methyl 2-(allyloxymethyl)acrylate, 5 parts by weight of polyethylene glycol were added Diacrylate (average number of repetitions of alkylene oxide n=4) and 0.5 parts by weight of a photocrosslinking agent (Omnirad (registered trademark) 184) were stirred and mixed to obtain the adhesive composition of Example 1. This adhesive composition is applied on a release film (1) (a silicone resin as a release agent layer is applied, and the thickness of the base material is 100 μm) so that the thickness of the adhesive layer after drying becomes a predetermined value. After being coated on a polyethylene terephthalate (PET) film), the solvent was removed by drying at 90°C, and then it was aged for 7 days in an atmosphere of 23°C and 50% RH, so as to facilitate the thermal crosslinking agent. The adhesive layer is formed by crosslinking the adhesive composition. Further, a release film (2) having a peeling force lighter than the release film (1) and a base material having a thickness of 75 μm was attached to the surface of the adhesive layer to obtain The pressure-sensitive adhesive sheet A of Example 1 composed of the release film (1)/adhesive layer/release film (2) (the first-stage pressure-sensitive adhesive layer is formed). Ultraviolet (UV) is further irradiated to the adhesive layer after crosslinking with the heat-facilitating crosslinking agent, and the photocrosslinking agent is used for crosslinking. In this way, the adhesive sheet B of Example 1 in which the adhesive layer was sandwiched between the two release films (forming the second-stage adhesive layer) was obtained. The photocrosslinking is made of these two stages of crosslinking.

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

Examples 2 to 5 and Comparative Examples were obtained in the same manner as in the adhesive sheets A to B of the above-mentioned Example 1, except that the compositions of the additives were as shown in the descriptions of Groups (E) to (H) in Table 1, respectively. Adhesive Sheets A to B of 1 to 3.

[Table 1]

In Table 1, the numerical value of the weight part calculated|required by making the total of (A) group 100 weight part is shown. In addition, in Table 2, the compound name of the abbreviation symbol of each component used in Table 1 is shown. In addition, CORONATE (registered trademark) is a trade name of TOSOH CORPORATION, Duranate (registered trademark) is a trade name of Asahi Kasei Corporation, and Omnirad (registered trademark) is a trade name of IGM Resins B.V. Omnirad 184 is a photocrosslinking agent with 1-hydroxycyclohexyl phenyl ketone as the main component. Omnirad 651 is a photocrosslinking agent with 2,2-dimethoxy-2-phenylacetophenone as the main component. Omnirad TPO is a photocrosslinking agent mainly composed of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide.

[Table 2]

<Test method and evaluation>

If necessary, the release films (1) to (2) were peeled off from the adhesive sheets A to B in Examples 1 to 5 and Comparative Examples 1 to 3 to expose the adhesive layer, and the following test methods and measurement methods were used. Evaluate.

In addition, about the adhesive sheets A to B in Examples 1 to 5 and Comparative Examples 1 to 3, in order to comply with the following measurement methods and test methods, different thicknesses of the adhesive layers were prepared, and further, the first-stage adhesive was formed. A plurality of adhesive sheets A of the adhesive layer, or a plurality of adhesive sheets B having a second-stage adhesive layer formed thereon. When testing the adhesive layer of the first stage, the adhesive sheet A was used. In addition, when testing the adhesive layer of the second stage, the adhesive sheet B was used.

<Measuring method of total light transmittance>

Measurement method of light transmittance: According to JIS K7105, "Test methods for optical properties of plastics", the total light transmittance (%) of the adhesive layer with a thickness of 250 μm (the second-stage adhesive layer) was measured, and recorded as Table 3 "Total transmittance".

<Measurement method of haze value>

Measurement method of haze value: According to JIS K7136, "Determination method of haze of plastics-transparent materials", the haze value (%) of the adhesive layer (second-stage adhesive layer) with a thickness of 250 μm was measured, and recorded. The "initial haze value" of Table 3 was used. Furthermore, after standing for 240 hours in an atmosphere with a temperature of 60° C.×90% RH, it was taken out to a room temperature environment (23° C., 50% RH). Five minutes after taking out, the haze value (%) was measured with the release films (1) to (2) covering both surfaces of the pressure-sensitive adhesive layer, and described as "Haze value after wet heat" in Table 3.

<Evaluation of damp heat durability>

The wet heat durability of the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheet B in Examples 1 to 5 and Comparative Examples 1 to 3 was evaluated using the "haze value after wet heat" measured by the above-described measurement method of the haze value. In addition, the criterion of the wet heat durability was set as follows, and the evaluation result was described as "damp heat durability" in Table 3.

○: "Haze value after wet heat" is 4.0% or less.

Δ: "Haze value after wet heat" exceeds 4.0% and is 6.0% or less.

×: "Haze value after wet heat" exceeds 6.0%.

<Measuring method of adhesive force>

An adhesive layer with a thickness of 175 μm (the first-stage adhesive layer or the second-stage adhesive layer) was transferred from the adhesive sheets A to B to one side of a polyester film with a thickness of 50 μm to obtain a test sample. Such an adhesive film (optical film with an adhesive layer). The obtained adhesive films were respectively bonded to the non-tin surface of the alkali-free glass washed with acetone by a press roll, and after autoclaving at 50°C and 0.5MPa×20 minutes, the temperature was restored to 23°C×50°C. %RH in an air atmosphere, and after 1 hour. Using a tensile tester, the peel strength of the adhesive film after that was measured in accordance with JIS Z0237 "Test methods for adhesive tapes and adhesive sheets", and the peel strength when peeled at a speed of 300 mm/min in the 180° direction was measured as each Adhesion of the adhesive layer (N/25mm). In Table 3, the adhesive force measured using the adhesive layer in the first stage was referred to as "adhesive force after thermal crosslinking", and the adhesive force measured using the adhesive layer in the second stage was referred to as "adhesive force after photocrosslinking" Adhesion".

<Test method for step followability>

A 100 μm-thick adhesive layer (first-stage adhesive layer) cross-linked with a thermal crosslinking agent was transferred from the adhesive sheet A to a 188 μm-thick polyethylene phthalate resin film and lamination on one side of the sample to obtain an adhesive film as a sample. Then, under the conditions of a pressure of 80 kPa and a degree of vacuum of -100 kPa, using a vacuum laminating device, from above the adhesive layer (the first-stage adhesive layer), a printing step with a thickness of 42 μm was applied to the printing layer. A cover glass with a thickness of 1.1 mm is attached to the adhesive layer. Furthermore, step followability after autoclaving under the conditions of a temperature of 60° C., 6 atmospheres, and 30 minutes was confirmed with the naked eye. The judgment criteria for visual inspection were set as follows, and the evaluation results were described as "step followability" in Table 3.

(circle) : It follows the printing step difference, and there is no bubbling around the printing step difference at all.

△: There is a small amount of foaming around the printing step.

×: Blisters are present around the printing step.

Table 3 shows the evaluation results of the adhesive sheets A to B of Examples 1 to 5 and the adhesive sheets A to B of Comparative Examples 1 to 3.

[table 3]

In the adhesive sheets B of Examples 1 to 5 of the present invention, the adhesives having a thickness of 250 μm after being cross-linked through two stages of cross-linking by a thermal cross-linking agent and subsequent cross-linking by a photo-cross-linking agent The total light transmittance of the layer is 90% or more, and the "initial haze value" is 1.0% or less, and the "haze value after wet heat" is 4.0% or less, even if the adhesive layer is left in a humid heat environment for a long time. After that, it was taken out to a room temperature environment (temperature 23° C.×50% RH), and since it was excellent in optical properties, it was also excellent in wet heat durability.

In addition, the adhesive films produced using the adhesive sheets A to B of Examples 1 to 5 of the present invention had an adhesive force to soda lime glass of 10 N/25 mm or less after cross-linking with a thermal cross-linking agent, and further It is 25 N/25mm or more after cross-linking by two steps of cross-linking by a thermal cross-linking agent and subsequent cross-linking by a photo-cross-linking agent. Therefore, the handling performance (easy peeling from the adherend) at the time of reoperation of the adhesive layer after crosslinking with the thermal crosslinking agent is excellent, and the crosslinking by the thermal crosslinking agent and the subsequent photocrosslinking agent-based crosslinking agent are excellent. The adhesive layer after crosslinking in these two stages has high adhesive force.

In addition, when the pressure-sensitive adhesive layer (first-stage pressure-sensitive adhesive layer) having a thickness of 100 μm was formed on the pressure-sensitive adhesive films produced using the pressure-sensitive adhesive sheets A of Examples 1 to 5 of the present invention, the test of the step followability was As a result, the printing step with a thickness of 42 μm was followed, and there was no bubble at all around the printing step, and the step followability was excellent.

That is, according to the adhesive sheets A to B of Examples 1 to 5 of the present invention and the adhesive films produced using them, the step followability to the step such as frame printing of the adherend, which is the technical problem of the present invention, can be realized , An adhesive layer with good handling properties during reoperation and excellent wet heat durability.

On the other hand, with respect to the adhesive layers formed on the adhesive sheets A to B of Comparative Example 1, the copolymers obtained by copolymerizing two or more kinds of monomers contained the monomers of the (F) group without The adhesive sheet B of Comparative Example 1 was obtained by crosslinking so as to contain the monomer of the group (G), since the "haze value after wet heat" was low and the transparency was high, it was excellent in wet heat durability. In addition, the adhesive film produced using the adhesive sheet A of Comparative Example 1 had high "adhesion after thermal crosslinking", poor reworkability, bubbling around the printing step, and poor step followability.

In addition, the adhesive layers formed on the adhesive sheets A to B of Comparative Example 2 contained (F) a copolymer obtained by copolymerizing two or more monomers without containing the monomer of the group (F). It was obtained by crosslinking as a monomer in the group G), and since the "haze value after wet heat" of the adhesive sheet B of Comparative Example 2 was high, and the transparency was low, it was inferior to wet heat durability. Moreover, the "adhesive force after photocrosslinking" of the adhesive film produced using the adhesive sheet B of the comparative example 2 was very low. In addition, the adhesive film produced using the adhesive sheet A of Comparative Example 2 had bubbles around the printing step, and the step followability was poor.

In addition, the adhesive layers formed on the adhesive sheets A to B of Comparative Example 3 were obtained by copolymerizing two or more kinds of monomers in the form of monomers containing (F) group and (G) group. The adhesive sheet B of Comparative Example 3 had a low "haze value after wet heat" and high transparency, and thus was excellent in wet heat durability. Moreover, the "adhesive force after photocrosslinking" of the adhesive film produced using the adhesive sheet B of the comparative example 3 was a little low. In addition, the adhesive film produced using the adhesive sheet A of Comparative Example 3 had bubbles around the printing step, and the step followability was poor.

As described above, the adhesive sheets A to B of Comparative Examples 1 to 3 and the adhesive films produced using them were not able to achieve the level difference followability to the level difference such as frame printing of the adherend, which is the technical problem of the present invention, and the Adhesive layer with good handling properties and excellent wet heat durability.

In the pressure-sensitive adhesive sheets B of the above-mentioned Comparative Examples 1 to 3, the copolymer obtained by copolymerizing two or more kinds of monomers was cross-linked so as to contain the monomer of the group (F) and the comparative example 1 and the comparison The "haze value after wet heat" of the adhesive sheet B of Example 3 was low, and the wet heat durability of the adhesive layer was excellent. However, the "haze value after wet heat" of the adhesive sheet B of Comparative Example 2 obtained by crosslinking the copolymer obtained by copolymerizing two or more monomers so as not to contain the monomer of group (F) "High, the wet heat durability of the adhesive layer is poor. Therefore, in the adhesive composition for optics of the present invention, it was confirmed that the useful component for obtaining an adhesive layer having excellent wet heat durability is (F) having (meth)acryloyl and allyl in one molecule. A monomer of a (meth)acrylate having a base ether group and having two or more ethylenically unsaturated groups.

Claims (11)

1. An optical adhesive composition comprising: a copolymer obtained by copolymerizing at least two or more selected from the group consisting of a copolymerizable vinyl monomer and a nitrogen-containing vinyl monomer , the copolymerizable vinyl monomer does not have a carboxyl group in the functional group, but has any one of an alkyl group, a hydroxyl group, an alkoxy group and an aromatic group; (F) has a (meth)acryloyl group and Allyl ether group and monomer of (meth)acrylate having two or more ethylenically unsaturated groups; (G) having epoxy alkyl group and having two or more ethylenically unsaturated groups in one molecule (Meth)acrylate monomer; (E) thermal crosslinking agent; and (H) photocrosslinking agent. 2. The adhesive composition for optics according to claim 1, wherein The copolymer is a copolymer having a weight-average molecular weight of 200,000 to 1,000,000, which is composed of an alkyl (meth)acrylate having C1 to C18 carbon atoms with respect to 100 parts by weight of the (A) alkyl group in total. At least one of the monomers, at least one of (B) a nitrogen-containing vinyl monomer or an alkoxy-containing (meth)acrylic acid alkyl ester monomer, at least one or more of (B) a nitrogen-containing vinyl monomer or an alkoxy-containing (meth)acrylic acid alkyl ester monomer in an amount of 2.0-10 parts by weight, A total of 1.0 to 10 parts by weight of (C) at least one or more of the polyalkylene glycol mono(meth)acrylate monomers, and a total of 0.5 to 10 parts by weight of (D) copolymerizable ethylene having a hydroxyl group At least one or more of the base monomers, The adhesive composition for optics contains the (E) thermal crosslinking agent in a ratio of 0.01 to 5 parts by weight, and the adhesive composition for optics contains the thermal crosslinking agent in a ratio of 0.1 to 10 parts by weight with respect to 100 parts by weight of the (A). (F) Monomer of (meth)acrylate having (meth)acryloyl group and allyl ether group in one molecule and having two or more ethylenically unsaturated groups, in a ratio of 0.1 to 10 parts by weight A monomer containing the (G) (meth)acrylate having an epoxy group and having two or more ethylenically unsaturated groups in one molecule, and containing the (H) in a ratio of 0.01 to 5 parts by weight ) photocrosslinkers. 3. The adhesive composition for optics according to claim 1 or 2, characterized in that, after crosslinking based on the (E) thermal crosslinking agent and subsequent crosslinking based on the (H) photocrosslinking agent In these two stages of crosslinking, the total light transmittance of the adhesive layer with a thickness of 250 μm formed by crosslinking the optical adhesive composition is 90% or more, and the haze value is 1.0% or less. 4. The adhesive composition for optics according to claim 1 or 2, characterized in that, after crosslinking based on the (E) thermal crosslinking agent and subsequent crosslinking based on the (H) photocrosslinking agent In these two stages of cross-linking, the optical adhesive composition was cross-linked to form an adhesive layer with a thickness of 250 μm, and the adhesive layer was left to stand in an atmosphere with a temperature of 60° C.×90% RH for 240 hours , the haze value when taken out to a room temperature environment (temperature 23°C × 50% RH) is 4.0% or less. 5 . The optical adhesive composition according to claim 1 , wherein the (A) alkyl group has a (meth)acrylic alkyl group having C1 to C18 carbon atoms in a total of 100 parts by weight. 6 . In at least one or more of the ester monomers, the copolymer contains a C8-C18 alkyl (meth)acrylate having an alkyl group in a ratio of 50 parts by weight or more. 6. The optical adhesive composition according to claim 1 or 2, wherein the copolymer is copolymerized by (C) polyalkylene glycol mono(meth)acrylate monomer, so The optical adhesive composition contains (G) a monomer having an epoxy group and a (meth)acrylate having two or more ethylenically unsaturated groups in one molecule, the (C) and the above The average repeating number of the alkylene oxide of (G) is 4-14. 7 . An adhesive film obtained by laminating an adhesive layer on one side of a base material, the adhesive layer using the optical adhesive according to claim 1 . agent composition, and cross-linked with the (E) thermal cross-linking agent, or by using the optical adhesive composition according to any one of claims 1 to 6, and based on the (E) The cross-linking of the thermal cross-linking agent and the subsequent cross-linking based on the (H) optical cross-linking agent are two-stage cross-linking, The adhesive force of the adhesive layer crosslinked by the (E) thermal crosslinking agent to soda lime glass is 10 N/25 mm or less. The adhesive force of the adhesive layer to the soda lime glass after cross-linking in two stages of the subsequent cross-linking by the (H) photo-cross-linking agent is 25 N/25 mm or more. 8. An adhesive film, characterized in that it is formed by laminating an adhesive layer on one side of a polyethylene phthalate resin film having a thickness of 188 μm, the adhesive layer being formed by using the claims The adhesive composition for optics according to any one of 1 to 6, which is obtained by crosslinking with the (E) thermal crosslinking agent, wherein the adhesive film is formed through the adhesive layer having a thickness of 100 μm. When it was bonded to the glass having the printing step of the printing layer with a thickness of 42 μm, the followability to the printing step was good, and there was no bubble at all around the printing step. The film for touch panels using the adhesive film of Claim 7 or 8. The pressure-sensitive adhesive sheet obtained by laminating the pressure-sensitive adhesive layer cross-linked with the (E) thermal cross-linking agent using the optical pressure-sensitive adhesive composition according to any one of claims 1 to 6 It is formed between two pieces of release film that has been released from the mold. 11 . An optical film with an adhesive layer obtained by laminating an adhesive layer on at least one surface of an optical film, the adhesive layer using the optical film according to claim 1 . The adhesive composition is cross-linked by using the (E) thermal crosslinking agent, or by using the optical adhesive composition according to any one of claims 1 to 6, and based on the (E) ) Crosslinking by the thermal crosslinking agent and subsequent crosslinking by the (H) photocrosslinking agent are formed by crosslinking in two stages.