JP2018172571A - Optical adhesive composition, optical adhesive sheet, and optical laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical adhesive composition having excellent foaming resistance and/or peeling resistance.SOLUTION: An optical adhesive composition contains: a (meth) acryl copolymer, which contains, based on 100 pts.mass of monomer components constituting the (meth) acryl copolymer, a constitutional unit derived from (meth) acrylate having a C1-15 hydrocarbon group of 40-80 pts.mass; and 0.5-2.5 pts.mass of 1H-benzotriazol, based on 100 pts.mass of the total amount of the monomer components constituting the (meth) acryl copolymer.SELECTED DRAWING: None

Description

  The present invention relates to an optical pressure-sensitive adhesive composition, an optical pressure-sensitive adhesive sheet, and an optical laminate.

  A capacitive touch panel or the like has a cover panel on the forefront in order to protect the module. Conventionally, glass has been used as a material for the cover panel, but from the viewpoint of improving safety when broken, a transparent resin plate such as polycarbonate or polymethyl methacrylate has been used. .

  Patent Documents 1 and 2 disclose an optical pressure-sensitive adhesive sheet or tape for bonding between a cover panel and a touch sensor panel.

  However, when a resin plate is used for the cover panel, there arises a problem that the transparent adhesive of the optical pressure-sensitive adhesive sheet to be bonded to the resin plate is foamed or peeled off due to outgas generated from the resin plate by heating.

JP2009-155629 JP2014-145054

  An object of the present invention is to provide an optical pressure-sensitive adhesive composition, an optical pressure-sensitive adhesive sheet, and an optical laminate that have improved foam resistance and / or peel resistance.

  The inventors have unexpectedly found that when 1H-benzotriazole is added to the optical pressure-sensitive adhesive composition, foaming of the optical pressure-sensitive adhesive composition is suppressed, and the present invention has been completed. It was.

  That is, the present invention is as follows.

  Item 1. 40 to 80 parts by mass of a structural unit derived from a (meth) acrylic acid ester having a hydrocarbon group having 1 to 15 carbon atoms with respect to 100 parts by mass of the monomer component constituting the (meth) acrylic copolymer ( An optical pressure-sensitive adhesive composition containing 0.5 to 2.5 parts by mass of 1H-benzotriazole with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer and the (meth) acrylic copolymer. object.

  Item 2. An optical pressure-sensitive adhesive sheet obtained by polymerizing and curing the optical pressure-sensitive adhesive composition according to Item 1.

Item 3. Item 2. The optical pressure-sensitive adhesive sheet according to Item 2,
A first adherend laminated on the first surface of the optical pressure-sensitive adhesive sheet;
The optical laminated body provided with the 2nd to-be-adhered body laminated | stacked on the 2nd surface opposite to the said 1st surface of the said adhesive sheet for optics.

  Item 4. 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 4. The optical laminate according to Item 3.

  The optical pressure-sensitive adhesive composition, optical pressure-sensitive adhesive sheet and optical laminate of the present invention can exhibit excellent foam resistance and / or peel resistance.

(A) A perspective view showing an image display device provided with an optical layered product concerning one embodiment of the present invention, (B) An expansion exploded perspective view of a portion surrounded by a dotted line of Drawing 1 (A).

  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.

1. Optical pressure-sensitive adhesive composition The optical pressure-sensitive adhesive sheet of the present invention is formed by polymerizing the monomers in the optical pressure-sensitive adhesive composition to form a copolymer and further curing the copolymer.

  The optical pressure-sensitive adhesive composition is not particularly limited as long as it is transparent, but is preferably an acrylic pressure-sensitive adhesive composition containing (mono) acrylic acid ester as a main component monomer. In this case, a (mono) acrylic acid ester monomer is polymerized to form a (meth) acrylic copolymer, which is further cured to form an optical pressure-sensitive adhesive sheet.

  Hereinafter, the components of the acrylic pressure-sensitive adhesive composition of one embodiment of the optical pressure-sensitive adhesive composition of the present invention will be described.

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

  (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 (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and 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) acrylate such as decyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate; isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) ) (Meth) acrylic acid ester having an alicyclic hydrocarbon group such as acrylate; aromatic carbonization such as phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate (Meth) acrylic acid ester having a hydrogen 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 constituting the (meth) acrylic copolymer. It is.

  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 with respect to the total amount of monomer components constituting the (meth) acrylic copolymer. By being in this range, whitening resistance and polymerization stability are imparted to the optical pressure-sensitive adhesive composition. When the content is 5 mass or more, whitening of the optical pressure-sensitive adhesive composition during heating and humidification is more effectively suppressed. Moreover, the polymerization reaction of the monomer component which comprises a (meth) acryl copolymer will progress stably that content is 50 mass or less.

  Although content of the said component (A) and (B) is not limited, Preferably, the optical adhesive composition is 40-about 100 mass parts of monomer components whole quantity which comprises this (meth) acryl copolymer. A (meth) acrylic copolymer containing 80 parts by mass of (meth) acrylic acid ester (A) and 5 to 50 parts by mass of a hydroxy group-containing monomer (B) as monomer components is contained.

  The total amount of the monomer components constituting the (meth) acrylic copolymer is usually 50% by mass or more, preferably 60% by mass, more preferably 70% by mass, and still more preferably 80% with respect to the amount of the optical pressure-sensitive adhesive composition. % By mass. In one embodiment, particularly in the monomer component constituting the (meth) acrylic copolymer, the total amount of the (meth) acrylic acid ester (A) and the hydroxy group-containing monomer (B) satisfies the above ratio.

  The optical pressure-sensitive adhesive composition contains 0.5 to 2.5 parts by mass of 1H-benzotriazole (C) with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer. When the amount of 1H-benzotriazole (C) is less than 0.5 parts by mass, the foam resistance and / or peel resistance is lowered, and even when it exceeds 2.5 parts by mass, the foam resistance and / or peel resistance is lowered. To do. 1H-benzotriazole is known as a rust preventive, but it is surprising that it can improve foam resistance and / or peel resistance by containing a certain amount of 1H-benzotriazole in the optical pressure-sensitive adhesive composition. It is a knowledge that should be done.

  The optical pressure-sensitive adhesive composition can contain a silane coupling agent (D) for the purpose of improving foam resistance and suppressing whitening. It is preferable that content of a silane coupling agent (D) is 0.05-10 mass parts with respect to 100 mass parts of monomer components whole quantity which comprises a (meth) acryl copolymer, 0.1-5 masses More preferably, it is a part.

  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.-mercaptopropylmethyldimethoxysilane, and the like. As for the said silane coupling agent, 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 optical pressure-sensitive adhesive composition can optionally contain a small amount of (meth) acrylic acid (E) that does not cause corrosion of the conductive material, but a large amount of (meth) acrylic acid is contained in the conductive material. Since it is corrosive, the content of (meth) acrylic acid is preferably 0.5 parts by mass or less with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer. More preferably, it is 25 parts by mass or less.

  The pressure-sensitive adhesive composition of the present invention may contain a structural unit derived from a highly polar monomer as necessary. Examples of such highly polar monomers include vinyl pyrrolidone, (meth) acryloyl morpholine, vinyl morpholine, dialkyl (meth) acrylamide, and hydroxyalkyl acrylamide. When such a highly polar monomer is added, it is usually about 0.01 to 50 parts by mass with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer.

  Various additives may be added to the optical 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.), polymerization initiators, crosslinking agents, colorants (pigments or Dyes, etc.), ultraviolet absorbers, light stabilizers, chain transfer agents, polymerization inhibitors and the like. When such an additive is added, it is usually about 0.01 to 10 masses per 100 mass parts of the total amount of monomer components constituting the (meth) acrylic copolymer.

2. Method for producing optical pressure-sensitive adhesive composition, optical pressure-sensitive adhesive, and optical pressure-sensitive adhesive sheet Examples of the method for producing the optical pressure-sensitive adhesive composition include a mixture of monomer components constituting the (meth) acrylic copolymer. Is a method in which a (meth) acrylic copolymer is produced by radical polymerization in the presence of a polymerization initiator to obtain an optical pressure-sensitive adhesive composition. 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.

  The amount of the polymerization initiator used is not particularly limited, and is, for example, 0.001 to 50 parts by mass, preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer. About a part.

  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 adhesiveness of a 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.

  The optical pressure-sensitive adhesive comprising the optical pressure-sensitive adhesive composition of the present invention, particularly the acrylic pressure-sensitive adhesive, can take any form during the preparation process, but in terms of handling, it is solvent-based, emulsion-based, hot-melt It is preferably used in the form of a system, a photopolymerization system or the like. The optical pressure-sensitive adhesive can be used alone or in combination of two or more.

  The optical pressure-sensitive adhesive sheet of the present invention is formed from a pressure-sensitive adhesive layer formed by polymerizing, curing, and optionally molding the optical pressure-sensitive adhesive composition containing the (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 optical adhesive sheet has the said adhesive layer, the structure in particular will not be restrict | limited. Specifically, as the optical pressure-sensitive adhesive sheet, for example, (1) a substrate-less double-sided optical pressure-sensitive adhesive sheet having a configuration formed only from the pressure-sensitive adhesive layer, and (2) a pressure-sensitive adhesive layer on at least one surface of the substrate And a double-sided optical pressure-sensitive adhesive sheet having a structure in which adhesive surfaces are formed on both sides of the base material, and (3) an optical material with a base material having a structure in which an adhesive layer is formed on one surface of the base material An adhesive sheet for use. When the optical pressure-sensitive adhesive sheet is a double-sided optical 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. Even if the layer formed on the surface is an adhesive layer and the layer formed on the other surface of the substrate is an adhesive layer other than the adhesive layer (sometimes referred to as a “non-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. Examples of the plastic substrate include a transparent sheet made of a transparent resin such as acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, urethane, and polyimide. The substrate includes a release liner, and a known release liner for an optical pressure-sensitive adhesive sheet or tape can be used as the release liner. A base material functions as a to-be-adhered body which bonds the optical adhesive sheet of this invention.

  The optical 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 optical pressure-sensitive adhesive sheet of the present invention can have a form such as a tape or sheet. Therefore, the optical adhesive sheet includes an optical adhesive sheet or an adhesive tape.

  The method for producing the optical pressure-sensitive adhesive sheet of the present invention is not limited, and in particular, as a method for producing the optical pressure-sensitive adhesive sheet of the present invention, a mixture of monomer components, a photopolymerization initiator, and additives as necessary, etc. And a monomer composition not containing a solvent is applied to a release treatment surface of a transparent synthetic resin film on which one surface is release-treated to form a monomer layer. The monomer component is obtained by superimposing the release treatment surface of another transparent synthetic resin film on which one surface has been released, and irradiating the monomer layer with light such as ultraviolet irradiation through the synthetic resin film. A method of radical polymerization of the mixture is preferably used. In addition, as said transparent synthetic resin film, a polyethylene terephthalate film etc. are mentioned, for example.

  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 ( Acetophenone-based photopolymerization initiators such as BASF, trade name “IRGACURE (registered trademark) 651”), 2-hydroxy-2-cyclohexylacetophenone (BASF, trade name “IRGACURE (registered trademark) 184”), benzyl Ketal photopolymerization initiators such as dimethyl ketal, halogenated ketones, Sill 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 components whole quantity which comprises 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 pressure-sensitive 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 pressure-sensitive adhesive sheet.

  Although the thickness of the said adhesive layer of the optical adhesive tape of this invention is not specifically limited, A preferable minimum is 5 micrometers and a preferable upper limit is 1 mm. The adhesive layer can exhibit the adhesive force with respect to a to-be-adhered body as the thickness of the said adhesive layer is 5 micrometers or more. When the thickness of the pressure-sensitive adhesive layer is 1 or less, handleability is good. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 10 μm, a further preferable lower limit is 20 μm, a more preferable upper limit is 500 μm, and a further preferable upper limit is 300 μm.

  Even if the optical pressure-sensitive adhesive sheet of the present invention is exposed to a high temperature during pretreatment, various production process steps, product use, etc., the foam resistance and / or peel resistance is suppressed.

  The optical pressure-sensitive adhesive sheet of the present invention is excellent in foam resistance and / or peel resistance.

  The optical pressure-sensitive adhesive sheet of the present invention is an image display for an electric 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 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, the cover panel and the display panel module are bonded, It can be used suitably for bonding a touch panel module and a display panel module. The optical 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 pressure-sensitive adhesive sheet of the present invention is also included in the present invention.

  The optical laminate according to the present invention includes an optical pressure-sensitive adhesive sheet, a first adherend laminated on the first surface of the optical pressure-sensitive adhesive sheet, and a first surface opposite to the first surface of the optical pressure-sensitive adhesive sheet. And a second adherend laminated on the surface of the second. 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. 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 metal or metal oxide thin film, or a touch panel module. Preferably there is.

  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 adhesive sheet, and a cover panel and a display panel module via an optical adhesive sheet. Examples include a bonded cover panel-display panel module laminate 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 adhesive sheet. As the cover panel, a glass plate or a resin plate is preferably used. The optical pressure-sensitive adhesive sheet is particularly suitable when the cover panel is a polycarbonate plate or an acrylic plate.

  Moreover, the film laminated body with a transparent electrode layer by which two of the films with a transparent electrode layer formed of the metal or metal oxide through the said optical adhesive sheet was laminated | stacked is also preferable as an optical laminated body.

  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 10 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 adhesive sheet 12. The touch panel module 14 has a structure in which a film 16 with a metal thin film, an optical pressure-sensitive adhesive sheet 17, a film 16 with a metal thin film, an optical pressure-sensitive adhesive sheet 17, and a support 18 are laminated in this order. The portion where the optical pressure-sensitive adhesive sheet 12, the metal thin film-attached film 16, the optical pressure-sensitive adhesive sheet 17, and the metal thin film-attached film 16 are laminated in this order is a metal thin film-attached film laminate 19.

  In FIG. 1, the touch panel module 14 is bonded to the display panel module 15 via the optical pressure-sensitive adhesive sheet 17. In this case, the touch panel module 14 is bonded to the touch panel module 14 with the support 18 peeled off.

  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 Part, 25 parts by mass of 4-hydroxybutyl acrylate, 0.05 parts by mass of 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE 651, BASF) and after replacing with nitrogen, viscosity (BH viscosity) The reactor was irradiated with ultraviolet rays until the total No. 5 rotor, 10 rpm, measurement temperature 25 ° C.) reached about 4 Pa · s, to prepare an optical pressure-sensitive adhesive composition in which a part of the monomer component was polymerized. Table 1 shows the content (parts by mass) of each component.

(2) Production of optical adhesive sheet The optical adhesive composition solution obtained in 1 has 0.05 part by mass of IRGACURE651 (IRGACURE651, BASF), silane coupling agent (KBM-403, epoxy structure). 1 part by mass of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.) was added 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. Optical pressure-sensitive adhesive by irradiating UV light with an illuminance of ² mW / cm ² with a chemical lamp for 360 seconds so as to face the pressure-sensitive adhesive layer formed by coating and to have a pressure-sensitive adhesive layer thickness of 300 μm. A sheet was produced.

(Examples 2-4, Comparative Examples 1-5)
Optical adhesives of Examples 2 to 4 and Comparative Examples 1 to 5 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. A sheet was obtained.

(Evaluation)
The following evaluation was performed about the adhesive sheet for optics obtained by the Example and the comparative example. The results are shown in Table 1. The optical pressure-sensitive adhesive sheets of Examples 1 to 4 were excellent in foam resistance and peel resistance, but the optical pressure-sensitive adhesive sheets in Comparative Examples 1 to 5 had low foam resistance and peel resistance.

(Evaluation of foam release resistance)
The obtained optical pressure-sensitive adhesive sheet was cut so as to have a planar shape of 45 mm × 60 mm. One of the release polyethylene terephthalate films of the cut optical pressure-sensitive adhesive sheet is peeled off, and the exposed surface of the optical pressure-sensitive adhesive sheet is a 1 mm thick polycarbonate resin plate (trade name “MR-58” (Mitsubishi Gas Chemical Co., Ltd.). Furthermore, the other release polyethylene terephthalate film of the optical pressure-sensitive adhesive sheet was peeled off, and the exposed surface of the optical pressure-sensitive adhesive sheet was a glass plate (trade name “S-9112”, manufactured by MATSUNAMI). The test piece which is a module laminated body by which the adhesive sheet for optics and the glass plate were laminated | stacked in this order on the resin board was bonded together.

  Thereafter, this test piece is left under high temperature and high humidity of 85 ° C. and relative humidity (RH) 85%, and when foaming and peeling are not seen after 1000 hours, ○, and when foaming or peeling is seen As evaluated.

Claims (4)

40 to 80 parts by mass of a structural unit derived from a (meth) acrylic acid ester having a hydrocarbon group having 1 to 15 carbon atoms with respect to 100 parts by mass of the monomer component constituting the (meth) acrylic copolymer ( An optical pressure-sensitive adhesive composition containing 0.5 to 2.5 parts by mass of 1H-benzotriazole with respect to 100 parts by mass of the total amount of monomer components constituting the (meth) acrylic copolymer and the (meth) acrylic copolymer. object. An optical pressure-sensitive adhesive sheet obtained by polymerizing and curing the optical pressure-sensitive adhesive composition according to claim 1. An optical pressure-sensitive adhesive sheet according to claim 2,
A first adherend laminated on the first surface of the optical pressure-sensitive adhesive sheet;
The optical laminated body provided with the 2nd to-be-adhered body laminated | stacked on the 2nd surface opposite to the said 1st surface of the said adhesive sheet for optics. 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 laminate according to claim 3.

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