JP2018172668A - Acrylic adhesive composition and adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic adhesive composition that has excellent foaming resistance, and whitening resistance and/or yellowing resistance.SOLUTION: An acrylic adhesive composition contains an amino group-containing compound. The content of the amino group-containing compound is 0.001 to 3 pts.mass (exclusive) relative to 100 pts.mass of the total amount of monomer components of (meth)acryl copolymers, and further contains a silane coupling agent.SELECTED DRAWING: None

Description

  The present invention relates to an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.

  As the front plate of touch panels mounted on automobiles and airplanes, not only glass but also resin plates are used for the purpose of safety or weight reduction. The resin plates are connected with touch panel modules by optical transparent adhesive sheets. It is pasted together. However, since the resin plate has a property of generating outgas by heating, there is a problem that bubbles due to the outgas are generated between the resin plate and the adhesive sheet during heating.

  Patent Document 1 relates to an acrylic pressure-sensitive adhesive composition containing an acrylic resin (A) obtained by copolymerizing a copolymer component containing a hydroxyl group-containing monomer (a1) and an amino group-containing monomer (a2). We are working to improve foam resistance by adding the group-containing monomer (a2).

JP 2013-213203 A

  By the way, when an amine compound is added, the foaming resistance of the acrylic pressure-sensitive adhesive composition is improved. However, when the amount of the amine compound is increased, whitening or yellowing with time occurs, and this trade-off is a problem.

  An object of the present invention is to provide an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet excellent in foam resistance and whitening resistance, or foam resistance and yellowing resistance.

  In order to achieve the above-mentioned object, the present inventors use a relatively small amount of an amino group-containing compound, and further use a silane coupling agent to improve foam resistance, whitening resistance and The inventors have found that it is possible to achieve compatibility with yellowing resistance and have completed the present invention.

  That is, the present invention is as follows.

Item 1.
Including the amino group-containing compound, the content of the amino group-containing compound is less than 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer, and the silane coupling agent is further added. An acrylic pressure-sensitive adhesive composition.

  Item 2. Item 2. The acrylic pressure-sensitive adhesive composition according to item 1, wherein the amino group-containing compound is a tertiary amine.

  Item 3. Item 3. The acrylic pressure-sensitive adhesive composition according to item 1 or 2, wherein the amino group-containing compound is at least one of an amino group-containing (meth) acrylic monomer and an amino group-containing (meth) acrylamide monomer.

  Item 4. Item 4. The acrylic pressure-sensitive adhesive composition according to any one of items 1 to 3, wherein the acid value is 5 mgKOH / g or less.

  Item 5. Item 5. The acrylic pressure-sensitive adhesive composition according to any one of Items 1 to 4, comprising 0.01 to 10 parts by mass of a silane coupling agent, based on 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer.

  Item 6. (Meth) acryl containing 40 to 80 parts by weight of (meth) acrylic acid ester and 5 to 50 parts by weight of a hydroxy group-containing monomer as monomer components with respect to 100 parts by weight of the total amount of monomer components of the (meth) acrylic copolymer. Item 6. The acrylic pressure-sensitive adhesive composition according to any one of Items 1 to 5, which contains a copolymer.

  Item 7. Item 7. An optical transparent pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer comprising the acrylic pressure-sensitive adhesive composition according to any one of items 1 to 6.

  Item 8. Item 8. The optical transparent adhesive sheet according to Item 7, the first adherend laminated on the first surface of the optical transparent adhesive sheet, and the first surface of the optical transparent adhesive sheet are opposite to each other. And a second adherend laminated on the second surface of the optical laminate.

  Item 9. The first adherend is a cover panel, a film with a metal or metal oxide thin film, a glass with a metal or metal oxide thin film, a scattering prevention film, a super birefringence film, an antireflection film, a polarizing plate or a touch panel module. The second adherend is a cover panel, a film with a metal or metal oxide thin film, a glass with a metal or metal oxide thin film, an anti-scattering film, a super birefringent film, a polarizing plate, a touch panel module, or a display panel module. Item 10. The optical laminate according to Item 9.

  Even when the acrylic pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet of the present invention are applied to a touch panel mounted on an automobile or an aircraft, they can exhibit excellent foam resistance, whitening inhibition and / or yellowing resistance. it can.

It is a perspective view which shows an image display apparatus provided with the optical laminated body which concerns on one Embodiment of this invention, and its one part disassembled perspective view.

  In this specification, “and / or” means at least one, for example, “A and / or B” refers to only A, only B, and both A and B.

  In this specification, “(meth) acryl” refers to “acryl” and “methacryl”. Thus, for example, (meth) acrylic acid includes acrylic acid and methacrylic acid, and (meth) acrylic acid ester includes acrylic acid ester and methacrylic acid ester. The same applies to other compounds in which “(meth) acryl” is used.

  In the present specification, the “acrylic pressure-sensitive adhesive composition” refers to a pressure-sensitive adhesive composition containing an acrylate ester as a main component.

1. Acrylic pressure-sensitive adhesive composition The optically transparent pressure-sensitive adhesive sheet of the present invention is obtained by polymerizing monomers in an acrylic pressure-sensitive adhesive composition containing (mono) acrylic acid ester as a main component monomer, and a (meth) acrylic copolymer. It is formed by doing.

  The components of the acrylic pressure-sensitive adhesive composition according to one embodiment of the present invention will be described.

    The acrylic pressure-sensitive adhesive composition contains (meth) acrylic acid ester (A) and hydroxy group-containing monomer (B) as monomer components.

  (Meth) acrylic acid ester (A) is the main monomer component that constitutes the base polymer in the acrylic pressure-sensitive adhesive, and can be used alone or in combination of two or more (meth) acrylic acid esters. Can also be used. The proportion of each (meth) acrylic acid ester when (meth) acrylic acid ester is combined can be arbitrarily selected. The (meth) acrylic acid ester is preferably a (meth) acrylic acid ester having a hydrocarbon group having 1 to 15 carbon atoms.

  Examples of the (meth) acrylic acid ester (A) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl ( (Meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate , Alkyl ester (meth) acrylates such as tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate; isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl ( (Meth) acrylate and other (meth) acrylic acid esters having an alicyclic hydrocarbon group; aromatics such as phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, and phenoxydiethylene glycol (meth) acrylate (Meth) acrylic acid ester having a hydrocarbon group;

  The content of the (meth) acrylic acid ester (A) is preferably 40 to 95 parts by mass, more preferably 40 to 80 parts by mass with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer. is there.

  Examples of the monomer (B) containing a hydroxy group include hydroxy (meth) acrylate, and examples of the hydroxy (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxy Examples thereof include hydroxyalkyl (meth) acrylates such as butyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate. It is preferable that carbon number of the alkyl of hydroxyalkyl (meth) acrylate is 2-6. As the monomer containing a hydroxy group, only one kind can be used, or two or more kinds can be used in combination.

  The content of the monomer (B) containing a hydroxy group is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer. By being in this range, whitening suppression and polymerization stability are imparted to the acrylic pressure-sensitive adhesive composition. When the content is 5 parts by mass or more, whitening of the acrylic pressure-sensitive adhesive composition during heating and humidification is more effectively suppressed. Further, when the content is 50 parts by mass or less, the polymerization reaction of the monomer component of the (meth) acrylic copolymer proceeds stably.

  The acrylic pressure-sensitive adhesive composition contains the amino group-containing compound (C), and the content of the amino group-containing compound is 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer. Part, and further contains a silane coupling agent.

  The amino group-containing compound (C) is preferably a tertiary amine.

  The amino group-containing compound (C) is preferably at least one of an amino group-containing (meth) acrylic monomer and an amino group-containing (meth) acrylamide monomer.

  Examples of amino group-containing (meth) acrylic monomers include aminoalkyl (meth) acrylates such as aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, aminoisopropyl (meth) acrylate; N Monosubstituted amino group-containing (meth) acrylates such as N-alkylaminoalkyl (meth) acrylates including-(t-butyl) aminoethyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate and other N, N-dialkylaminoalkyl (meth) acrylates Substituted amino group Available (meth) Akureto; and the like. Among these, N, N-dialkylaminoalkyl (meth) acrylate is preferable.

  Examples of amino group-containing (meth) acrylamide monomers include N, N-dialkylaminoalkyl (meth) acrylamides such as dimethylaminopropyl (meth) acrylamide.

  From the viewpoint of yellowing resistance, the upper limit of the content of the amino group-containing compound (C) is more preferably 1.5 parts by mass, and still more preferably 0.8 parts by mass. The lower limit of the content is more preferably 0.05 parts by mass.

  Examples of the silane coupling agent (D) include vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyltri Methoxysilane, γ-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, γ-mercaptopropyltri Tokishishiran, .gamma.-mercaptopropyl triethoxy silane, mercaptopropyl butyl trimethoxy silane, and .gamma.-mercaptopropyl methyl dimethoxy silane, and the like. As for the said silane coupling agent (D), only 1 type may be used and 2 or more types may be used together. Of these, a silane coupling agent having an epoxy group is preferable.

  The content of the silane coupling agent (D) is preferably 10 parts by mass or less with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer. The content of the silane coupling agent (D) is preferably 0.01 to 10 parts by mass, more preferably 0.05 parts by mass or more, with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer. 5 parts by mass or less. In this way, by including a relatively high concentration of the silane coupling agent compared to the conventional one, when the optical transparent adhesive sheet is applied to the resin plate, the whitening of the laminate of the adhesive sheet and the resin plate is suppressed. can do. In particular, when a tertiary amine is used as the amino group-containing compound (C), whitening resistance can be improved while maintaining foam resistance. When the content of the silane coupling agent (D) is 0.01 parts by mass or more (preferably 0.05 parts by mass or more), whitening of the acrylic pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet formed therefrom is preferable. And / or yellowing can be prevented. When the content of the silane coupling agent (D) is 10 parts by mass or less, the release paper or the release film can be easily peeled from the pressure-sensitive adhesive sheet.

  The acrylic pressure-sensitive adhesive composition may optionally contain a structural unit derived from a highly polar monomer. Examples of such highly polar monomers include vinyl pyrrolidone, (meth) acryloyl morpholine, vinyl morpholine, dialkyl (meth) acrylamide, and hydroxyalkyl acrylamide.

  The acrylic pressure-sensitive adhesive composition may optionally contain a small amount of (meth) acrylic acid to the extent that corrosion of the conductive material does not proceed. A small amount of (meth) acrylic acid contributes to the improvement of foam resistance, but a large amount of (meth) acrylic acid impairs whitening resistance and yellowing resistance, so the content of (meth) acrylic acid is (meta ) It is preferably 0.5 parts by mass or less, more preferably 0.25 parts by mass or less, based on 100 parts by mass of the total amount of monomer components constituting the acrylic copolymer.

  Although content of the said component (A) and (B) is not limited, Preferably, an acrylic adhesive composition is 40-80 mass parts with respect to 100 mass parts of monomer components whole quantity of a (meth) acryl copolymer. A (meth) acrylic copolymer containing (meth) acrylic acid ester (A) and 5-50 parts by mass of a hydroxy group-containing monomer (B) as monomer components. In this case, it is preferable not to include (meth) acrylic acid, but when (meth) acrylic acid is included, it is 0.25 parts by mass or less with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer. It is preferable.

  Various additives may be added to the acrylic pressure-sensitive adhesive composition of the present invention as necessary. Examples of such additives include tackifier resins (eg, rosin resins, terpene resins, petroleum resins, coumarone / indene resins, styrene resins, etc.), thermal stabilizers, antioxidants, antistatic agents, Examples include various known additives such as thickeners, fillers, colorants (such as pigments or dyes), ultraviolet absorbers, and surfactants. When such an additive is added, it is usually about 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer.

  In order to provide more excellent foam resistance, whitening resistance and / or yellowing resistance, the acid value of the acrylic pressure-sensitive adhesive composition is preferably 5 mgKOH / g or less. Also, from the viewpoint of corrosion resistance, the acid value of the acrylic pressure-sensitive adhesive composition is preferably 5 mgKOH / g or less.

2. Method for producing acrylic pressure-sensitive adhesive composition, acrylic pressure-sensitive adhesive, and pressure-sensitive adhesive sheet As a method for producing the above-mentioned acrylic pressure-sensitive adhesive, for example, a mixture of monomer components constituting the (meth) acrylic copolymer is used as a polymerization initiator. A method of producing a (meth) acrylic copolymer by radical polymerization in the presence of an acrylic pressure-sensitive adhesive is mentioned. If necessary, other components such as the above-mentioned various additives can be added to the mixture.

  Examples of the polymerization initiator include persulfates, organic peroxides (peroxide-based initiators), azo-based compounds (azo-based initiators), and the like. Of these, organic peroxides or azo compounds are preferred in view of the influence on the metal thin film when a metal thin film containing a metal such as ITO or a metal oxide is used as the adherend.

  Examples of the persulfate include potassium persulfate, sodium persulfate, and ammonium persulfate.

  Examples of the organic peroxide include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, lauroyl peroxide. 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t -Butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like.

  Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis (2-methylpropionic acid) dimethyl, , 4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazoline) -2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-dimethyleneisobutylamidine) dihydrochloride, and the like. .

  The usage-amount of a polymerization initiator is not restrict | limited in particular, For example, it is 0.001-50 mass parts with respect to 100 mass parts of monomer components of a (meth) acryl copolymer, Preferably it is about 0.01-10 mass parts. is there.

  In the present invention, the (meth) acrylic copolymer obtained by polymerization using each monomer component may be used after being dried, and the (meth) acrylic copolymer is further crosslinked with a crosslinking agent. It may be cured by using. By crosslinking the (meth) acrylic copolymer, durability such as heat resistance is imparted to the (meth) acrylic copolymer in addition to the releasability and tackiness of the substrate (such as a release liner). The (meth) acrylic copolymer can be crosslinked during or after the formation of the acrylic pressure-sensitive adhesive layer.

  As the above-mentioned crosslinking agent, conventionally known ones can be used, but polyisocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, and melamine compounds are preferable, and polyisocyanate compounds are particularly preferable. is there. A crosslinking agent can be used individually or in mixture of 2 or more types. Examples of polyisocyanate compounds include tolylene diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate, diphenylmethane diisocyanate double product, reaction product of trimethylolpropane and tolylene diisocyanate, trimethylolpropane. And the reaction product of hexamethylene diisocyanate, polyether polyisocyanate, polyester polyisocyanate and the like. The amount of the polyisocyanate compound used is, for example, about 0.01 to 20 parts by mass (preferably 0.05 to 15 parts by mass) with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer. is there. In one embodiment, the acrylic pressure-sensitive adhesive composition of the present invention containing the (meth) acrylic copolymer includes a crosslinking agent. In another embodiment, the acrylic pressure-sensitive adhesive composition of the present invention containing the (meth) acrylic copolymer does not contain a crosslinking agent.

  The total amount of monomer components of the (meth) acrylic copolymer is usually 50 parts by mass or more, preferably 60 parts by mass, more preferably 70 parts by mass, and still more preferably 100 parts by mass of the acrylic pressure-sensitive adhesive composition. 80 parts by mass (typically 50% by mass or more, preferably 60% by mass, more preferably 70% by mass, and even more preferably 80% by mass with respect to the amount of the acrylic pressure-sensitive adhesive composition. The monomer component of the (meth) acrylic copolymer is the total amount of (meth) acrylic acid ester (A), hydroxy group-containing monomer (B), and optional dialkyl (meth) acrylamide and / or diethylacrylamide. Satisfy the ratio.

  The acrylic pressure-sensitive adhesive composed of the acrylic pressure-sensitive adhesive composition of the present invention can take any form during the preparation process, but in terms of handleability, such as a solvent system, an emulsion system, a hot melt system, and a photopolymerization system. It is preferable to use it in the form. An acrylic adhesive can be used individually or in combination of 2 or more types.

  The optical transparent pressure-sensitive adhesive sheet of the present invention is formed from a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive composition containing the above (meth) acrylic copolymer. The pressure-sensitive adhesive layer may have any form of a single layer or a laminate. Although it will not restrict | limit especially if it is a range which does not impair high transparency etc. as a thickness of an adhesive layer, For example, it can select from the range of about 1-several thousand micrometers.

  In addition, the formation method in particular of an adhesive layer is not restrict | limited. For example, using a conventional coater (gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, etc.), an acrylic adhesive is applied to a predetermined surface (for example, the surface of a substrate). Etc.) to form a pressure-sensitive adhesive layer.

  If the adhesive sheet has the said adhesive layer, the structure in particular will not be restrict | limited. Specifically, as the pressure-sensitive adhesive sheet, for example, (1) a baseless double-sided pressure-sensitive adhesive sheet having a configuration formed only from the pressure-sensitive adhesive layer, (2) a pressure-sensitive adhesive layer is formed on at least one surface of the base material, and Examples include a double-sided pressure-sensitive adhesive sheet with a base material having a pressure-sensitive adhesive surface formed on both sides of the base material, and (3) a pressure-sensitive adhesive sheet with a base material with a pressure-sensitive adhesive layer formed on one surface of the base material. When the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet with a substrate, the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) formed on both surfaces of the substrate may be a pressure-sensitive adhesive layer, and is formed on one surface of the substrate. Even if the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer formed on the other surface of the substrate is a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer (sometimes referred to as a “non-pressure-sensitive adhesive layer”). Good.

  Base materials include paper base materials such as paper, fiber base materials such as cloth, non-woven fabric and net; metal base materials such as metal foil and metal plate; plastic base materials such as plastic films and sheets. An appropriate thin layered body such as a substrate; a rubber-based substrate such as a rubber sheet; or the like can be used. As the substrate, a plastic substrate such as a plastic film or sheet can be suitably used. The substrate includes a release liner, and a known release liner for pressure-sensitive adhesive sheets or tapes can be used as the release liner. A base material functions as a to-be-adhered body which bonds the transparent adhesive sheet for optics of this invention.

  The pressure-sensitive adhesive sheet may be formed in a form wound in a roll shape, or may be formed in a form in which sheets are laminated. That is, the transparent adhesive sheet for optics of the present invention can have a form such as a tape or sheet. Therefore, an adhesive sheet or an adhesive tape is contained in an adhesive sheet.

  The method for producing the optical transparent pressure-sensitive adhesive sheet of the present invention is not particularly limited. As a method for producing a substrate-less transparent adhesive sheet for optics, for example, a coating film is formed by applying the acrylic pressure-sensitive adhesive composition to a release treatment surface of a release material, and the obtained coating film There may be mentioned a method in which a laminate is obtained by superimposing a newly prepared release material so that the release treatment surface is in contact with the coating film, and then the resulting laminate is pressed with a rubber roller or the like.

  In addition, as a method of producing the optical transparent adhesive sheet of the present invention, a mixture of monomer components used as a raw material for the (meth) acrylic copolymer is radically polymerized by bulk polymerization, and the (meth) acrylic copolymer is obtained. A method of producing a sheet at the same time as manufacturing is also suitable.

  The bulk polymerization is preferably photopolymerization because the heat of polymerization is easily removed and the reaction is easily controlled.

  In particular, as a method for producing the optical transparent pressure-sensitive adhesive sheet of the present invention, a monomer composition containing a mixture of monomer components, a photopolymerization initiator, and, if necessary, an additive and not containing a solvent, After forming a monomer layer by coating on the release surface of a transparent synthetic resin film on which one surface has been released, another transparent surface on which one surface has been released is applied on the monomer layer. A method in which a mixture of monomer components is radically polymerized by overlaying the release treatment surfaces of the synthetic resin film and performing light irradiation such as ultraviolet irradiation on the monomer layer through the synthetic resin film is suitably used. In addition, as said transparent synthetic resin film, a polyethylene terephthalate film etc. are mentioned, for example.

  When the optical transparent pressure-sensitive adhesive sheet of the present invention is produced by photopolymerization, since a crosslinked structure can be formed simultaneously with polymerization, the mixture of monomer components contains a polyfunctional (meth) acrylate having two or more polymerizable functional groups. You may contain.

  Examples of the polyfunctional (meth) acrylate include 1,6-hexanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and hydrogenated polybutadiene di (meth). ) Acrylate, trimethylolpropane triacrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyurethane di (meth) acrylate, polyester di (meth) acrylate, and the like. Among them, 1,6-hexanediol diacrylate, polypropylene glycol diacrylate, hydrogenated polybutadiene diacrylate, polyurethane diacrylate, and polyester are preferred because of the low decrease in stress dispersibility of the obtained optical transparent adhesive sheet and excellent adhesive performance. Diacrylate is preferred.

  When the mixture of the monomer components contains the polyfunctional (meth) acrylate, the blending amount of the polyfunctional (meth) acrylate is preferably a lower limit in 100 parts by mass of the total amount of the monomer components of the (meth) acrylic copolymer. 0.02 part by mass, and a preferred upper limit is 5 parts by mass. When the blending amount of the polyfunctional (meth) acrylate is 0.02 part by mass or more, the (meth) acrylic copolymer is sufficiently cross-linked, and the obtained optical transparent adhesive sheet has cohesive strength. Good workability. When the blending amount of the polyfunctional (meth) acrylate is 5 parts by mass or less, the obtained optical transparent pressure-sensitive adhesive sheet has an adhesive force and initial adhesiveness to the adherend, and maintains reliability. The more preferable minimum of the compounding quantity of the said polyfunctional (meth) acrylate is 0.05 mass part in 100 mass parts of monomer component whole quantity of a (meth) acryl copolymer, and a more preferable upper limit is 3 mass parts.

  Examples of the photopolymerization initiator include ketone-based light such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone (trade name “IRGACURE (registered trademark) 2959” manufactured by BASF). Polymerization initiator, α-hydroxy-α, α′-dimethyl-acetophenone (manufactured by BASF, trade name “IRGACURE (registered trademark) 1173”), methoxyacetophene, 2,2-dimethoxy-2-phenylacetophene (BASF) Acetophenone photopolymerization initiator such as 2-hydroxy-2-cyclohexylacetophenone (trade name “IRGACURE® 184” manufactured by BASF) Ketal photopolymerization initiators such as ketals, halogenated ketones, polymers Le phosphino, dimethylsulfoxide, and the like acyl phosphonium isocyanate is.

  As a compounding quantity of the said photoinitiator, the preferable minimum with respect to 100 mass parts of monomer component whole quantity of a (meth) acryl copolymer is 0.01 mass part, and a preferable upper limit is 5 mass parts. When the blending amount of the photopolymerization initiator is 0.01 parts by mass or more, polymerization of the monomer component mixture proceeds, and the obtained optical transparent adhesive sheet has cohesive force and necessary physical properties are obtained. When the blending amount of the photopolymerization initiator is 5 parts by mass or less, the amount of radicals generated is kept low during light irradiation, and the molecular weight of the resulting (meth) acrylic copolymer becomes good. The more preferable lower limit of the amount of the photopolymerization initiator is 0.03 parts by mass, and the more preferable upper limit is 1 part by mass.

  Examples of the lamp used for the light irradiation include a lamp having a light emission distribution at a wavelength of 400 nm or less. Examples of the lamp having a light emission distribution at a wavelength of 400 nm or less include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp. Can be mentioned. Among these, the light in the active wavelength region of the photopolymerization initiator is efficiently emitted, and there is little light absorption of components other than the photopolymerization initiator contained in the monomer layer, so that light can enter the monomer layer. A chemical lamp is preferred because it can reach sufficiently to effectively polymerize the mixture of monomer components.

  The light irradiation intensity and irradiation time in the light irradiation can be appropriately selected by those skilled in the art according to the polymerization degree of the (meth) acrylic copolymer or the performance of the optical transparent adhesive sheet.

  Even if the transparent adhesive sheet for optical use of the present invention is exposed to high temperature and / or high humidity during pretreatment, various manufacturing process steps, product use, etc., whitening and / or yellowing is suppressed.

  The transparent adhesive sheet for optics of the present invention is excellent in foam resistance, whitening suppression and / or yellowing resistance.

  The optical transparent adhesive sheet of the present invention is an image of an electrical product, electronic product, or optical device having an optically transparent member, such as a mobile phone, a smartphone, a personal computer, electronic paper, a tablet personal computer, and a game machine. When manufacturing a display device (for example, a liquid crystal display, an OECD display, an electrowetting display), the cover panel for protecting the surface and the touch panel module are bonded, or the cover panel and the display panel module are bonded. The touch panel module and the display panel module can be suitably used for bonding. The pressure-sensitive adhesive sheet can also be applied to optical applications such as optical films other than these.

  An optical laminate in which substrates are laminated via the optical transparent adhesive sheet of the present invention is also included in the present invention.

  The optical laminated body according to the present invention includes an optical transparent adhesive sheet, a first adherend laminated on the first surface of the optical transparent adhesive sheet, and the first surface of the optical transparent adhesive sheet. And a second adherend laminated on the opposite second surface. The first adherend is a cover panel, a film with a metal or metal oxide thin film, a glass with a metal or metal oxide thin film, a scattering prevention film, a super birefringence film, an antireflection film, a polarizing plate or a touch panel module. Is preferred. The second adherend is a cover panel, a film with a metal or metal oxide thin film, a glass with a metal or metal oxide thin film, an anti-scattering film, a super birefringent film, a polarizing plate, a touch panel module, or a display panel module. It is preferable.

  The cover panel is a cover glass, a polycarbonate plate, or a polymethyl methacrylate plate, and the first adherend is a cover glass, a polycarbonate plate, a polymethyl methacrylate plate, a film with a metal or metal oxide thin film, or a touch panel. Preferably it is a module.

  Specific examples of the optical laminate include a cover panel-touch panel module laminate in which a cover panel and a touch panel module are bonded via an optical transparent adhesive sheet, and a cover panel and a display panel module via an optical transparent adhesive sheet. And a touch panel module display panel module laminate in which a touch panel module and a display panel module are bonded via an optical transparent adhesive sheet. As the cover panel, a glass plate or a resin plate is preferably used. The optical transparent adhesive sheet is particularly suitable when the cover panel is a polycarbonate plate or an acrylic plate.

  A film laminate with a transparent electrode layer in which two films with a transparent electrode layer formed of a metal or metal oxide are laminated through the optical transparent adhesive sheet is also preferable as the optical laminate.

  The optical laminate is suitably used for an image display device including the optical laminate and an image display unit.

  FIG. 1 is a perspective view showing an image display device 1 including an optical laminated body according to an embodiment of the present invention, and an exploded perspective view of a part thereof.

  The image display device 10 has a structure in which a cover panel 13 for protecting the surface is bonded onto a touch panel module 14 via an optical transparent adhesive sheet 12. The touch panel module 14 has a structure in which a film 16 with a metal thin film, an optical transparent adhesive sheet 17, a film 16 with a metal thin film, an optical transparent adhesive sheet 17, and a support 18 are laminated in this order. A portion where the optical transparent adhesive sheet 12, the film 16 with a metal thin film, the optical transparent adhesive sheet 17 and the film 16 with a metal thin film are laminated in this order is a film laminate 19 with a metal thin film. A portion in which the film laminate 19 with a metal thin film, the optical transparent adhesive sheet 17 and the support 18 are laminated in this order is a touch panel module 20.

  In FIG. 1, the touch panel module is bonded to the display panel module via the optical transparent adhesive sheet 17. In this case, the touch panel module is bonded with the support 18 being peeled from the touch panel module.

  Examples of the image display device 10 include a mobile phone and a portable information terminal. Examples of the support 18 include a release-treated polyethylene terephthalate film.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1
(1) Manufacture of (meth) acrylic acid ester copolymer solution A reactor equipped with a thermometer, a stirrer, a condenser tube, and an ultraviolet irradiation device, 45 parts by mass of 2-ethylhexyl acrylate and 30 parts by mass of isobornyl acrylate Parts, 25 parts by mass of 4-hydroxybutyl acrylate, 0.05 parts by mass of dimethylaminopropylacrylamide, 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE® 651, BASF) 0. After addition of 05 parts by mass and nitrogen substitution, the reactor was irradiated with ultraviolet rays until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 25 ° C.) reached about 4 Pa · s. An optical pressure-sensitive adhesive composition in which a part of the monomer component was polymerized was produced. Table 1 shows the content (parts by mass) of each component.

(2) Production of pressure-sensitive adhesive sheet 0.05 parts by mass of a photopolymerization initiator (IRGACURE (registered trademark) 651, manufactured by BASF) into the solution of the optical pressure-sensitive adhesive composition obtained in (1) above, silane coupling An agent (KBM-403, a silane coupling agent having an epoxy structure, manufactured by Shin-Etsu Chemical Co., Ltd.) was added in mass and stirred. The obtained solution was coated on the release-treated surface of a release polyethylene terephthalate film (SP3000, manufactured by Toyo Cloth), and the release-treated surface of the release polyethylene terephthalate film (SP4107, manufactured by Toyo Cloth) was the above. It is placed on the release polyethylene terephthalate film so that it faces the pressure-sensitive adhesive layer formed by coating and the thickness of the pressure-sensitive adhesive layer is 300 μm, and UV light with an illuminance of 2 mW / cm 2 is applied for 360 seconds with a chemical lamp. Irradiation produced a transparent adhesive sheet for optics.

(Examples 2-10, Comparative Examples 1-2)
Optical transparency of Examples 2 to 10 and Comparative Examples 1 and 2 in the same manner as in Example 1 except that the monomer types and ratios constituting the (meth) acrylic acid ester copolymer are as shown in Table 1. An adhesive sheet was obtained.

(Evaluation)
The following evaluation was performed about the adhesive sheet obtained by the Example and the comparative example. The results are shown in Table 1. The optical transparent adhesive sheets of Examples 1 to 10 were excellent in foaming resistance and whitening resistance (further yellowing resistance in Examples 1 to 6 and 8 to 10). Furthermore, in addition to these properties, the optical transparent adhesive sheets of Examples 1 to 9 were excellent in corrosion resistance.

(1) Evaluation of foam resistance The obtained adhesive sheet was cut so as to have a planar shape of 45 mm × 60 mm. One release polyethylene terephthalate film of the cut pressure-sensitive adhesive sheet was peeled, and the exposed surface of the pressure-sensitive adhesive sheet was bonded to a 1 mm thick resin plate (trade name “MR-58” (manufactured by Mitsubishi Gas Chemical Company)). Further, the other release polyethylene terephthalate film of the pressure-sensitive adhesive sheet is peeled off, and the exposed surface of the pressure-sensitive adhesive sheet is bonded onto a glass plate (trade name “S-9112”, manufactured by MATSUNAMI), on the resin plate, A test piece which was a module laminate in which the pressure-sensitive adhesive sheet and the glass plate were laminated in this order was obtained.

  Thereafter, the obtained module laminate was treated in an autoclave at 45 ° C. and 0.45 MPa for 15 minutes, and then left overnight in an environment of 23 ° C. and 50% RH. From the next day, the temperature was 85 ° C. and 85%. It left still for 1000 hours on the conditions of RH, and obtained the cover panel-touch panel module laminated body. The bubble generation state in the adhesive interface of the obtained cover panel-touch panel module laminate was visually observed.

  When no bubbles with a size of 0.1 mm or more were observed at all, “◯ (no foaming resistance)”, one or more bubbles with a size of 0.1 mm or more per cover panel-touch panel module laminate The observed bubble was evaluated as “× (with foam resistance)”.

(2) Evaluation of whitening resistance As shown in (1) above, a test piece having a layer structure of resin plate / adhesive layer / glass plate was produced.

  Next, this test piece was left under high temperature and high humidity of 85 ° C. and 85% relative humidity (RH), and the Δhaze value (%) of the test piece before starting to stand and after leaving for 1000 hours was measured with a spectrocolorimeter. (Product name “CM-3600D”, manufactured by Konica Minolta Co., Ltd.) was used, and the calculation was performed according to the following formula.

ΔHaze value (%)
= {Haze value after leaving for 1000 hours (%)}-{Haze value before starting to stand (%)}
The case where the Δhaze value was 1 or less was evaluated as “◯”, the case where it was larger than 1 and 3 or less was evaluated as “Δ”, and the case where it was larger than 3 was evaluated as “X”.

(3) Evaluation of yellowing resistance As shown in (1) above, a test piece having a layer structure of resin plate / adhesive layer / glass plate was prepared.

  Next, this test piece is left under high temperature and high humidity at 85 ° C. and 85% relative humidity (RH), and the Δb * value (%) of the test piece before starting to stand and after leaving for 1000 hours is measured with a spectrocolorimeter. (Product name “CM-3600D”, manufactured by Konica Minolta Co., Ltd.) was used, and the calculation was performed according to the following formula.

Δb * value (%)
= {B * value (%) after leaving for 1000 hours}-{b * value (%) before starting to stand}
The case where the Δb * value was 1 or less was evaluated as “◯”, the case where it was larger than 1 was evaluated as “Δ”, and the case where it was larger than 1.5 was evaluated as “X”.

(4) Measurement of acid value The acid value was measured as follows using a sample obtained by peeling the polyethylene terephthalate film on both sides of the pressure-sensitive adhesive sheet.

  Into a 100 mL Erlenmeyer flask, 0.5 g to 1 g of a sample and 60 mL of a toluene / methanol = 70/30 (volume) mixed solvent were added and dispersed while stirring overnight at room temperature, and then 0.1 mol using a potentiometric titrator. Potentiometric titration with / L potassium hydroxide alcohol solution was performed, and the obtained inflection point was taken as the end point. A blank test was also conducted by the same method, and the acid value was calculated from the following formula. As a potentiometric titrator, AT-500N manufactured by Kyoto Electronics Industry Co., Ltd. was used, and a composite glass electrode was used as an electrode.

(5) Evaluation of corrosion resistance The above (1) except that a glass plate with a metal oxide thin film (product name “Glass with ITO film (sputtered product) 0002”, manufactured by GEOMATEC)) is used instead of the resin plate. By a similar method, a test piece (metal oxide thin film glass plate / adhesive layer / glass plate layer) which is a module laminate in which an adhesive sheet and a glass plate are laminated in this order on a metal oxide thin film glass plate Having a structure).

  Next, this test piece was left under high temperature and high humidity of 85 ° C. and relative humidity (RH) 85%, and the resistance measurement value of the glass plate with the metal oxide thin film of the test piece before starting to stand and after leaving for 1000 hours was measured. Using a non-contact resistance measuring device (product name “EC-80P”, manufactured by Napson), measurement was performed from the glass side with the metal oxide thin film. Based on the obtained measured value, the resistance change rate was calculated by the following formula.

Resistance change rate (%)
= {(Measured value after leaving for 1000 hours−Measured value before starting to stand) / Measured value before starting to stand} × 100
The case where the resistance change rate was 20% or less was evaluated as “◯”, and the case where the resistance change rate was larger than 20% was evaluated as “X”.

Claims (9)

Including the amino group-containing compound, the content of the amino group-containing compound is less than 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer, and the silane coupling agent is further added. An acrylic pressure-sensitive adhesive composition. The acrylic pressure-sensitive adhesive composition according to claim 1, wherein the amino group-containing compound is a tertiary amine. The acrylic pressure-sensitive adhesive composition according to claim 1 or 2, wherein the amino group-containing compound is at least one of an amino group-containing (meth) acrylic monomer and an amino group-containing (meth) acrylamide monomer. The acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the acid value is 5 mgKOH / g or less. The acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 4, comprising 0.01 to 10 parts by mass of a silane coupling agent based on 100 parts by mass of the total amount of monomer components of the (meth) acrylic copolymer. (Meth) acryl containing 40 to 80 parts by weight of (meth) acrylic acid ester and 5 to 50 parts by weight of a hydroxy group-containing monomer as monomer components with respect to 100 parts by weight of the total amount of monomer components of the (meth) acrylic copolymer. The acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 5, comprising a copolymer. The transparent adhesive sheet for optics which has an adhesive layer which consists of an acrylic adhesive composition in any one of Claims 1-6. The optical transparent adhesive sheet according to claim 7, the first adherend laminated on the first surface of the optical transparent adhesive sheet, and the first surface of the optical transparent adhesive sheet. The optical laminated body provided with the 2nd to-be-adhered body laminated | stacked on the 2nd surface opposite. The first adherend is a cover panel, a film with a metal or metal oxide thin film, a glass with a metal or metal oxide thin film, a scattering prevention film, a super birefringence film, an antireflection film, a polarizing plate or a touch panel module. The second adherend is a cover panel, a film with a metal or metal oxide thin film, a glass with a metal or metal oxide thin film, an anti-scattering film, a super birefringent film, a polarizing plate, a touch panel module, or a display panel module. The optical laminated body according to claim 8.