KR20210121108A - A laminate, an optical film, an image display device, and a manufacturing method therefor - Google Patents

Abstract

A polarizing plate with a pressure-sensitive adhesive layer having a novel configuration is provided. A polarizing plate containing an ultraviolet absorber and an adhesive layer on at least one surface of the polarizing plate, wherein the adhesive layer has a base polymer, a photocuring agent, and a molar extinction coefficient at a wavelength of 380 nm of 15 [Lmol ^-1 cm ^-1 ] It is a laminated body which is a layer formed of the adhesive composition containing the above photoinitiator.

Description

A laminate, an optical film, an image display device, and a manufacturing method therefor

The present invention relates to a laminate including a polarizing plate and an adhesive layer, an optical film and an image display device containing the same, and a method for manufacturing an image display device.

In a liquid crystal display device (LCD) or the like, a polarizing plate is affixed to both sides or one side of a liquid crystal cell from the image formation method thereof. As a polarizing plate, a polarizing film in which a protective film such as a triacetyl cellulose film is adhered to both sides of a polarizer in which a dichroic material such as iodine or a dichroic dye is adsorbed and stretched to a polyvinyl alcohol-based film is generally used. . When affixing a polarizing plate to a panel, an adhesive is used normally, and the polarizing plate with an adhesive layer which provided the adhesive layer previously on one side of the polarizing plate is generally used.

As a necessary characteristic calculated|required by the adhesive used for a polarizing plate, long-term adhesiveness (peel durability) at the time of bonding a polarizing plate with an adhesive layer to a panel is calculated|required. For example, it is calculated|required that problems, such as peeling and floating|lifting which originate in an adhesive, do not generate|occur|produce even in a high-temperature, high-humidity environment.

On the other hand, when bonding a polarizing plate to a panel using an adhesive, bonding defects, such as mixing of a bubble and a shift|offset|difference of an attachment position, may generate|occur|produce. When bonding defect generate|occur|produces, a polarizing plate is peeled off from a panel, and a panel is reused. For this reason, the re-peelability (rework property) which can peel easily a polarizing plate from a panel without adhesive residue is calculated|required of an adhesive after a fixed period of time passes from sticking. With the recent trend of panel thinning and enlargement, the demand for panel rehabilitation is increasing, and reworkability is an important item. However, since durability and reworkability have a trade-off relationship, it is a characteristic difficult to be compatible, In order to achieve coexistence, examination is performed. For example, Patent Document 1 discloses a polarizing plate with a pressure-sensitive adhesive layer designed to have low tackiness immediately after bonding to an adherend and to increase adhesive strength after heating.

Japanese Patent Laid-Open No. 2018-060172

There is still a demand for a polarizing plate with a pressure-sensitive adhesive layer having a novel configuration having properties such as adhesion or reworkability.

The present inventors discovered that the said subject could be solved by the laminated body which laminated|stacked the adhesive layer formed of the adhesive composition containing a base polymer, a photocuring agent, and a specific photoinitiator on a polarizing plate, and came to complete this invention .

The present invention includes the following embodiments.

[1] A polarizing plate comprising an ultraviolet absorber;

having an adhesive layer on at least one surface of the polarizing plate,

The pressure-sensitive adhesive layer is a layer formed of a pressure-sensitive adhesive composition comprising a base polymer, a photocuring agent, and a ^{photopolymerization initiator having a molar extinction coefficient of 15 [Lmol -1} cm ^{-1 ] or more at a wavelength of 380 nm, the laminate.}

[2] The laminate according to [1], wherein the polarizing plate has a light transmittance at 380 nm of 20% or less.

[3] The laminate according to [1] or [2], wherein the pressure-sensitive adhesive layer can be cured by irradiation with energy actinic rays in a wavelength range of 380 nm or more and 450 nm or less.

[4] The laminate according to any one of [1] to [3], wherein the adhesive force after curing of the pressure-sensitive adhesive layer is larger than the adhesive strength before curing.

[5] The laminate according to any one of [1] to [4], wherein the adhesive layer before curing by 90-degree peeling at a rate of 300 mm/min to alkali free glass of the pressure-sensitive adhesive layer is 7 N/25 mm or less.

[6] The laminate according to any one of [1] to [5], wherein the adhesive layer after curing by 90-degree peeling at a rate of 300 mm/min to alkali-free glass is 5 N/25 mm or more.

[7] The laminate according to any one of [1] to [6], wherein the pressure-sensitive adhesive composition further contains a sensitizer.

[8] The laminate according to any one of [1] to [7], wherein the photopolymerization initiator contains at least one selected from the group consisting of an oxime compound, a metallocene compound, an acylphosphine compound, and an aminoacetophenone compound. sifter.

[9] The ultraviolet absorber contains at least one selected from the group consisting of a benzophenone-based compound, an oxalic acid anilide-based compound, a cyanoacrylate-based compound, a benzotriazole-based compound, and a triazine-based compound, [1] to [ 8] The laminate as described in any one of.

[10] The laminate according to any one of [1] to [9], wherein the pressure-sensitive adhesive composition contains 1 to 50 parts by weight of the photocuring agent and 0.01 to 3 parts by weight of the photopolymerization initiator based on 100 parts by weight of the base polymer. sifter.

[11] The laminate according to any one of [1] to [10], wherein the base polymer contains an acrylic polymer.

[12] The laminate according to [11], wherein the acrylic polymer contains a hydroxyl group-containing monomer and a nitrogen-containing monomer as monomer components.

[13] The laminate according to any one of [1] to [12], wherein the photocuring agent contains a polyfunctional (meth)acrylate.

[14] The laminate according to any one of [1] to [13], wherein the polarizing plate has a polarizer and a transparent protective film on at least one surface of the polarizer, and the transparent protective film contains the ultraviolet absorber.

[15] An optical film comprising the laminate according to any one of [1] to [14].

[16] An image display device comprising the laminate according to any one of [1] to [14].

[17] The device according to [16], wherein the pressure-sensitive adhesive layer includes a curing reaction product of the base polymer and the photocuring agent.

[18] The method for manufacturing the image display device according to [16] or [17],

Disposing a laminate through the pressure-sensitive adhesive layer on a panel, and irradiating the pressure-sensitive adhesive layer with energy actinic rays in a wavelength range of 380 nm or more and 450 nm or less to cure the pressure-sensitive adhesive layer.

[19] The method according to [18], wherein the amount of irradiation with energy actinic rays in a wavelength range of 380 nm or more and 450 nm or less to the pressure-sensitive adhesive layer is 1000 mJ/cm ^{2 or more.}

The present invention has one or more of the following effects.

(1) The laminated body which can be used as a polarizing plate with an adhesive layer is provided. The laminate of this invention is used suitably for image display apparatuses, such as an optical film and a liquid crystal display device (LCD), for example.

(2) The laminate of the present invention can increase the adhesive force by photocuring the pressure-sensitive adhesive layer after adhesion to an adherend such as a panel. ADVANTAGE OF THE INVENTION According to the preferable aspect of this invention, adhesive force increases after photocuring, providing the rework property immediately after bonding, and the outstanding long-term adhesiveness (peelability durability) is provided.

(3) The pressure-sensitive adhesive layer constituting the laminate of the present invention is photocurable, and since the timing of curing after bonding to an adherend can be arbitrarily set, it is possible to flexibly respond to the lead time of the process.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the laminated body of one Embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. In addition, this invention is not limited to the following embodiment, In the range which does not deviate from the summary, it can change arbitrarily and can implement it. In addition, in description of drawing, the same code|symbol is attached|subjected to the same element, and the overlapping description is abbreviate|omitted. Dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from actual ratios.

In addition, all documents and publications described in the present specification are incorporated herein by reference in their entirety, regardless of their purpose. In addition, this specification includes the disclosure content of the claims, specification and drawings of Japanese Patent Application No. 2019-011976 (filed on January 28, 2019), which is a Japanese patent application that is the basis for claiming the priority of the present application.

One aspect of the present invention has a polarizing plate containing an ultraviolet absorber, and an adhesive layer on at least one surface of the polarizing plate, wherein the adhesive layer has a base polymer, a photocuring agent, and a molar extinction coefficient at a wavelength of 380 nm of 15 [Lmol ^-1 cm ^-1 ] It relates to a layer formed of a pressure-sensitive adhesive composition containing a photopolymerization initiator or more, the laminate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows one Embodiment of the polarizing film with an adhesive layer using a laminated body.

The polarizing film 10 with an adhesive layer is comprised including the laminated body 6 provided with the adhesive layer 4 on one main surface of the polarizing plate 3 . The pressure-sensitive adhesive layer 4 is fixedly laminated on one main surface of the polarizing plate 3 . 1, the polarizing plate 3 is comprised as a polarizing film provided with the polarizer 1 and the transparent protective films 2, 2' formed on both surfaces of the polarizer 1, The transparent protective film 2, 2' ) contains a UV absorber. In addition, the transparent protective film may be provided only on the single side|surface of a polarizer. In addition, the ultraviolet absorber may be contained only in one side of a transparent protective film. Although not shown in FIG. 1, the polarizer 1 and the transparent protective films 2 and 2' may be laminated|stacked through intervening layers, such as an adhesive bond layer, an adhesive layer, and an undercoat layer (primer layer). In addition, the ultraviolet absorber may be contained in the other layer (For example, an adhesive bond layer, an adhesive layer, an undercoat layer, etc.) which comprises a polarizing plate.

The pressure-sensitive adhesive layer 4 is a photocurable pressure-sensitive adhesive containing a base polymer, a photocuring agent, and a ^{photopolymerization initiator having a molar extinction coefficient at a wavelength of 380 nm of 15 [Lmol -1} cm ^-1 ] or more, and photocuring by irradiation with energy actinic rays As a result, the adhesive force (peel strength) with the adherend increases.

The polarizing plate 10 with an adhesive layer affixes the adhesive layer 4 to a to-be-adhered body, and is used.

The separator 5 is temporarily attached to the surface of the adhesive layer 4 of the polarizing film 10 with an adhesive layer shown in FIG. As the separator 5, for example, by providing a peeling layer by a peeling agent on the single side|surface of a sheet-like base material (liner base material), what was comprised so that the said single side might become a peeling surface can be used preferably. Before bonding to an adherend, the separator 5 is peeled off from the surface of the pressure-sensitive adhesive layer 4, and the exposed surface of the pressure-sensitive adhesive layer 4 is bonded to the surface of the adherend, whereby the laminate 6 is temporarily adhered to the adherend. do. The thickness of the separator 5 is usually 3 to 200 µm, preferably about 10 to 100 µm.

Alternatively, the separator 5 is omitted and the polarizing plate 3 in which the surface that does not face the pressure-sensitive adhesive layer 4 of the polarizing plate 3 is used as a peeling surface is used, and the polarizing film 10 with an pressure-sensitive adhesive layer is wound, The form (roll form) may be sufficient as the adhesive surface which does not oppose the polarizing plate 3 of the adhesive layer 4 contact|abuts against the surface which does not oppose the adhesive layer 4 of the polarizing plate 3, and was protected. Before bonding to an adherend, the laminate 6 is temporarily adhered to the adherend by exposing the surface of the pressure-sensitive adhesive layer 4 and bonding the exposed surface of the pressure-sensitive adhesive layer 4 to the surface of the adherend.

The separator 5 is peeled off and removed from the surface of the pressure-sensitive adhesive layer 4 of the polarizing film 10 with an pressure-sensitive adhesive layer 10 shown in FIG. By bonding to , the laminate 6 is laminated on the surface of the adherend. Before the photocuring of the pressure-sensitive adhesive layer 4 , the polarizing plate 3 is temporarily attached to the adherend through the pressure-sensitive adhesive layer 4 . By photocuring the pressure-sensitive adhesive layer 4 , the adherend and the polarizing plate 3 are fixed through the pressure-sensitive adhesive layer 4 .

In this specification, "sticking" is a state in which two laminated layers are firmly adhered, and peeling at the interface between them is impossible or difficult. "Temporary adhesion" is a state in which the adhesive force between the two laminated layers is small and can be easily peeled off at the interface of both.

Hereinafter, the member which comprises the polarizing plate 10 with an adhesive layer which concerns on the said embodiment is demonstrated.

<Polarizer>

The polarizing plate contains an ultraviolet absorber. Although the structure of a polarizing plate is not specifically limited, It is preferable that a polarizing plate has a polarizer and a transparent protective film on at least one surface of a polarizer.

(polarizer)

A polarizer is not specifically limited, A various thing can be used. As the polarizer, for example, a dichroic substance such as iodine or a dichroic dye is adsorbed to a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene/vinyl acetate copolymer-based partially saponified film. and polyene-based oriented films such as those axially stretched, dehydrated products of polyvinyl alcohol, and dehydrochlorinated products of polyvinyl chloride. Among these, a polarizer containing a polyvinyl alcohol-based film and a dichroic substance such as iodine is suitable.

Although the thickness in particular of these polarizers is not restrict|limited, Generally, it is 2-25 micrometers.

A polarizer obtained by uniaxially stretching a polyvinyl alcohol-based film by dyeing it with iodine can be produced by, for example, immersing a polyvinyl alcohol-based film in an aqueous solution of iodine to dye it, and stretching it to 3 to 7 times its original length. It can also be immersed in aqueous solutions, such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride, etc. as needed. If necessary, the polyvinyl alcohol-based film may be immersed in water before dyeing and washed with water. In addition to being able to wash the surface of the polyvinyl alcohol-based film by washing the polyvinyl alcohol-based film with water and the anti-blocking agent, swelling the polyvinyl alcohol-based film also has an effect of preventing unevenness such as staining of dyeing. Extending|stretching may be performed after dyeing|staining with iodine, may be extended|stretched while dyeing|staining, and may dye|stain with iodine after extending|stretching. It can be extended also in aqueous solutions, such as boric acid and potassium iodide, and a water bath.

(Transparent protective film)

A transparent protective film is not specifically limited, A various thing can be used. As a material constituting the transparent protective film, those having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like are preferable. For example, Polyester-type polymers, such as a polyethylene terephthalate and a polyethylene naphthalate; Cellulose polymers, such as a diacetyl cellulose and a triacetyl cellulose; acrylic polymers such as polymethyl methacrylate; styrenic polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); polycarbonate-based polymers; polyolefin-based polymers such as polyethylene, polypropylene, cycloolefin-based polymer, polyolefin having a norbornene structure, and ethylene/propylene copolymer; vinyl chloride-based polymers; amide-based polymers such as nylon and aromatic polyamide; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyether ether ketone-based polymers; polyphenylene sulfide-based polymers; vinyl alcohol-based polymers; vinylidene chloride-based polymers; vinyl butyral-based polymer; arylate-based polymers; polyoxymethylene-based polymers; and epoxy polymers or blends of the above polymers. These protective films are bonded to a polarizer by an adhesive bond layer normally. In addition, a transparent protective film can be formed by using thermosetting resins, such as (meth)acrylic type, a urethane type, an acrylic urethane type, an epoxy type, a silicone type, or ultraviolet curable resin, apply|coating these to a polarizer, and hardening it.

As a transparent protective film, retardation film can be used. Examples of the retardation film include those having a phase difference of 40 nm or more in front retardation and/or 80 nm or more in thickness direction retardation. The front retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm. When using retardation film as a transparent protective film, since the said retardation film also functions as a polarizer protective film, thickness reduction can be aimed at. As retardation film, the birefringent film formed by carrying out the uniaxial or biaxial stretching process of a thermoplastic resin film is mentioned. The temperature of the stretching, the stretching ratio, and the like are appropriately set depending on the retardation value, the material of the film, and the thickness.

Although the thickness of a transparent protective film can be determined suitably, it is generally preferable that it is 3-200 micrometers from points, such as workability|workability, such as intensity|strength and handling property, and thin layer property. As the thickness increases, the amount of light transmitted decreases and the reaction of the polymerization initiator tends to be delayed. It exists in the tendency for members, such as a polarizer, and a panel, to deteriorate, so that thickness is thin. From such a viewpoint, 5-100 micrometers is more preferable, and 5-80 micrometers is still more preferable. A transparent protective film can also be used in multiple sheets or multiple layers.

Functional layers, such as a hard-coat layer, a reflection prevention layer, a sticking prevention layer, a diffusion layer, and an anti-glare layer, can be provided on the surface of a transparent protective film to which the polarizer is not adhere|attached. In addition, the functional layers such as the hard coat layer, anti-reflection layer, anti-stick layer, diffusion layer, and anti-glare layer may be provided on the transparent protective film itself, and separately from the transparent protective film. .

A pressure-sensitive adhesive layer may be provided on the surface of the functional layer such as the hard coat layer, the anti-reflection layer, the anti-stick layer, the diffusion layer, and the anti-glare layer.

The transparent protective film and the polarizer may be laminated through an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). The adhesive layer is not particularly limited as long as it is optically transparent, and may be composed of various types of adhesives such as water-based, solvent-based, hot-melt-based, and active energy ray-curable adhesives. You may provide an easily bonding layer between a transparent protective film and an adhesive bond layer.

(Ultraviolet absorber)

The ultraviolet absorber is contained in a polarizing plate for the main purpose of suppressing deterioration of the structural member (for example, a polarizer) of the image display apparatus by the ultraviolet light which injects. Especially, since a polarizer is easy to receive the influence by an ultraviolet light, it is preferable that a ultraviolet absorber is contained in the transparent protective film adjacent to a polarizer.

The ultraviolet absorber is not specifically limited, Various things can be used. Specific examples include a benzophenone-based compound, an oxalic acid anilide-based compound, a cyanoacrylate-based compound, a benzotriazole-based compound, and a triazine-based compound. The ultraviolet absorber can be used individually or by selecting two or more types. Especially, a benzotriazole type compound and a triazine type compound are preferable, and especially a triazine type compound is more preferable. The triazine-based compound can obtain a sufficient ultraviolet absorption effect with a small addition amount, and can prevent bleed-out or the like at the time of film forming.

Examples of the benzophenone-based compound include 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzo Phenone, 2-hydroxy-4-n-octyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 1,4-bis(4-benzoyl-3-hydroxyphenone )-butane and the like.

Examples of the anilide oxalate compound include N-(2-ethylphenyl)-N'-ethoxy-phenyl)oxalic acid amide, N-(2-dodecylphenyl)-N'-ethoxy-phenyl)oxalic acid amide, etc. can be heard

Examples of the cyanoacrylate-based compound include octyl-2-cyano-3,3-diphenyl acrylate.

Examples of the benzotriazole-based compound include 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole and 2-(3-dodecyl-5-methyl-2-hydroxyphenyl). Benzotriazole, 2-(3,5-di-(2-methyloctan-2-yl)-2-hydroxyphenyl)benzotriazole, 2-(3-tert-methyl-5-(octoxycarbonyl) Ethyl)-2-hydroxyphenyl)benzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl) phenol], 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazol-2-yl)-p-cresol, 2- (2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol; 2- [5-Chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6- Di-tert-butylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazol-2-yl )-4-methyl-6-(3,4,5,6-tetrahydro phthalimidylmethyl)phenol, methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl- Reaction product of 4-hydroxyphenyl)propionate/polyethylene glycol 300, 2-(2H-benzotriazol-2-yl)-6-(straight chain and branched dodecyl)-4-methylphenol, 2-(5 -Methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 3-(2H-benzotriazole zol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-C7-9 branched and straight chain alkyl esters, 2,2-methylenebis[6-(2H-benzotriazole-2- yl)-4-(1,1,3,3-tetramethylbutyl)phenol] and the like.

It does not specifically limit as a triazine type compound, Various things can be used. For example, the triazine-type compound described in WO2005/109052 and Unexamined-Japanese-Patent No. 2009-52021 can be used suitably. For example, 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy- 4-ethoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine, 2,4-di Phenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3, 5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxyl -4-octyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2 , 4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxy oxy)-1,3,5-triazine, 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3,5-triazine , 2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-alkyloxy-2-hydroxypropyl oxy)-5-α-cumylphenyl]-s-tri Ultraviolet absorbent having an azine skeleton (alkyloxy; long-chain alkyloxy groups such as octyloxy, nonyloxy, and decyloxy), 2,4,6-tris(2-hydroxy-4-hexyloxyphenyl)-1,3 ,5-triazine, 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4- dodecyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6- Tris(2-hydroxy-4-(1-(2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine, 2,4,6- Tris(2-hydroxy-3-methyl-4-hexyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-octyloxyphenyl) -1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4,6- Tris(2-hydroxy-3-methyl-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyethoxy painting nyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4 ,6-tris(2-hydroxy-3-methyl-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl -4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-(1-(2-ethoxyhexylox) Si)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine, 2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-( 3-alkyloxy-2-hydroxypropyl oxy)-5-α-cumylphenyl]-s-triazine backbone (alkyloxy; and ultraviolet absorbers having long-chain alkyloxy groups such as octyloxy, nonyloxy and decyloxy).

As a commercial item of a triazine type compound, Tinuvin 1577, Tinuvin 460, and Tinuvin 477 (made by BASF Japan) are mentioned. As a commercial item of a benzotriazole type compound, Adecastab LA-31 (made by ADEKA), Tinuvin 326 (made by BASF Japan), etc. are mentioned.

Content in particular of a ultraviolet absorber in case a ultraviolet absorber is contained in a transparent protective film is not restrict|limited. For example, 0.01 to 10 weight% is preferable with respect to the weight (100 weight%) of a transparent protective film, 0.01 to 7 weight% is more preferable, 0.05 to 5 weight% is still more preferable.

(light transmittance)

As for a polarizing plate, it is preferable that the light transmittance of wavelength 380nm is 20 % or less. Since the polarizing plate has such a UV absorption ability, even when the pressure-sensitive adhesive layer is photocured by irradiating an energy actinic ray from the polarizing plate side, deterioration of the polarizer can be suppressed. Although the lower limit of the light transmittance of wavelength 380 nm is not particularly limited, for example, it is preferable that the photocuring reaction by the polymerization initiator is accelerated and the function of the adhesive by increasing the adhesive force after photocuring is sufficiently exhibited, so that it is preferably 1% or more. . The light transmittance at a wavelength of 380 nm is more preferably 1 to 20%, still more preferably 1 to 15%, particularly preferably 1.5 to 12%. The light transmittance with a wavelength of 380 nm can be measured using a spectrophotometer.

By containing the photoinitiator mentioned later, the adhesive layer of this invention can irradiate an energy actinic ray from the polarizing plate side which has such UV absorption ability, and can harden an adhesive layer.

(thickness)

Although the thickness in particular of a polarizing plate is not restrict|limited, Usually, it is 10-200 micrometers.

<Adhesive layer>

An adhesive layer is a layer formed with the adhesive composition containing a base polymer, a photocuring agent, a photoinitiator, and a sensitizer as needed. The pressure-sensitive adhesive layer is a photocurable pressure-sensitive adhesive. The pressure-sensitive adhesive layer undergoes a photocuring reaction by irradiation with energy actinic rays, so that adhesion to an adherend may be improved. The pressure-sensitive adhesive layer may be a cured layer of the pressure-sensitive adhesive composition including a base polymer, a photocuring agent, a photopolymerization initiator and, if necessary, a sensitizer. For example, the pressure-sensitive adhesive layer includes a curing reaction product of a base polymer and a photocuring agent. It is preferable that an adhesive layer can be hardened|cured by irradiation of the energy actinic ray of the wavelength range of 380 nm or more and 450 nm or less.

Since the adhesive layer with a polarizing plate has small adhesive force before photocuring, rework is easy. The adhesive layer increases the adhesive force with an adherend by photocuring, and is excellent in long-term adhesiveness (peelability durability).

A thermosetting pressure-sensitive adhesive may cure over time in a storage state, whereas a photocurable pressure-sensitive adhesive hardly progresses in a general storage environment and is cured by irradiation with energy actinic rays. The laminate of the present invention has the advantage that the curing timing of the pressure-sensitive adhesive layer can be arbitrarily set, and it can respond flexibly to the lead time of the process and the like.

It is preferable that the adhesive force after hardening of an adhesive layer is larger than the adhesive force before hardening from a viewpoint of rework property and adhesiveness. A method of measuring the adhesive force before or after curing of the pressure-sensitive adhesive layer is not particularly limited. For example, the adhesive strength before and after curing of the pressure-sensitive adhesive layer is the adhesive strength before and after curing by 90-degree peeling at a speed of 300 mm/min to alkali-free glass of the pressure-sensitive adhesive layer (adhesive strength T1 before curing to alkali-free glass) and adhesive force T2) after curing to alkali-free glass. Specifically, T1 and T2, according to the 90° peeling test in JIS Z0237:2009, the pressure-sensitive adhesive layer before and after curing formed on alkali-free glass, the peeling angle of 90 degrees (that is, in the vertical direction) tensile rate 300mm It is measured as the adhesive force at the time of peeling from the said alkali free glass on the conditions of /min. In one embodiment, the ratio of the adhesive strength after curing of the pressure-sensitive adhesive layer to the adhesive strength before curing (for example, the adhesive strength after curing to the alkali-free glass / the adhesive strength before curing to the alkali-free glass (T2/T1)) , From a viewpoint of rework property and adhesiveness, Preferably it is 1 or more, More preferably, it is 1.5 or more, More preferably, it is 2 or more.

Adhesive force before curing (adhesion before curing to alkali-free glass, T1) by 90 degree peeling at a speed of 300 mm/min to alkali-free glass of the pressure-sensitive adhesive layer facilitates rework and prevents adhesive residue after peeling From the viewpoint of From the viewpoint of preventing peeling during storage or handling, the adhesion (T1) before curing to alkali-free glass is preferably 0.1N/25mm or more, more preferably 0.5N/25mm or more, and furthermore 0.7N/25mm or more. desirable.

Adhesive force (adhesive force after curing to alkali-free glass, T2) after curing by 90 degree peeling at a speed of 300 mm/min to alkali-free glass of the pressure-sensitive adhesive layer is excellent in long-term adhesion (peel strength, peel durability), From the viewpoint of excellent adhesion reliability with an adherend, 5N/25mm or more is preferable, 6N/25mm or more is more preferable, and 8N/25mm or more is still more preferable. It is so preferable that the adhesive force (T2) after hardening with respect to alkali free glass is high, Although there is no restriction|limiting in the upper limit, Usually, it is 20 N/25 mm or less.

The thickness of an adhesive layer is about 1-300 micrometers, for example. Although adhesiveness with a to-be-adhered body improves, so that the thickness of an adhesive layer is large, there exists a tendency for rework property to deteriorate. Therefore, 5-100 micrometers is preferable, as for the thickness of an adhesive layer, 8-50 micrometers is more preferable, 10-40 micrometers is still more preferable, 13-30 micrometers is especially preferable.

When a laminated body is used for optical devices, such as a display, 80 % or more is preferable, as for the total light transmittance of an adhesive layer, 85 % or more is more preferable, and 90 % or more is still more preferable. 2 % or less is preferable, as for the haze of an adhesive layer, 1 % or less is more preferable, 0.7 % or less is still more preferable, and 0.5 % or less is especially preferable.

The composition of the pressure-sensitive adhesive layer is not particularly limited as long as the adhesive strength to the adherend is improved by photocuring.

(Base Polymer)

The base polymer is a main component of the pressure-sensitive adhesive composition and is a major factor determining the adhesive strength of the pressure-sensitive adhesive.

It is preferable that the crosslinked structure is introduce|transduced into a base polymer from a viewpoint of making the adhesive layer before photocuring hard and making peeling from the to-be-adhered body at the time of rework easy.

The type of the base polymer is not particularly limited, and an acrylic polymer, a silicone polymer, a urethane polymer, a rubber polymer, or the like may be appropriately selected. The base polymer may be used alone or by selecting two or more types. In particular, since it is excellent in optical transparency and adhesiveness, and it is easy to control various properties such as frictional force, the pressure-sensitive adhesive composition preferably contains an acrylic polymer as a base polymer, and 50% by weight or more of the pressure-sensitive adhesive composition (more preferably is 60% by weight or more, more preferably 70% by weight or more) is preferably an acrylic polymer.

As an acryl-type polymer, what contains (meth)acrylic-acid alkylester as a main monomer component is used suitably. In addition, in this specification, "(meth)acryl" means acryl and/or methacryl. The content of the (meth)acrylic acid alkyl ester is preferably 40% by weight or more, more preferably 50% by weight or more, still more preferably 55% by weight or more with respect to the total amount (100% by weight) of the monomer components constituting the acrylic polymer. do.

As (meth)acrylic-acid alkylester, the (meth)acrylic-acid alkylester of C1-C20 of an alkyl group is used suitably. The alkyl group of the (meth)acrylic acid alkylester may be linear or may have a branch. Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, (meth) acrylate pentyl, (meth) acrylate isopentyl, (meth) acrylic acid neopentyl, (meth) acrylate hexyl, (meth) acrylate heptyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylate octyl, (meth) Isooctyl acrylate, (meth) nonyl acrylate, (meth) acrylate isononyl, (meth) acrylate decyl, (meth) acrylate isodecyl, (meth) acrylate undecyl, (meth) acrylate dodecyl, (meth) acrylic acid iso Tridodecyl, (meth)acrylic acid tetradecyl, (meth)acrylic acid isotetradecyl, (meth)acrylic acid pentadecyl, (meth)acrylic acid cetyl, (meth)acrylic acid heptadecyl, (meth)acrylic acid octadecyl, (meth) Acrylic acid isooctadecyl, (meth)acrylic acid nonadecyl, (meth)acrylic acid aralkyl, etc. are mentioned.

The acrylic polymer preferably contains, as a copolymerization component, a monomer component having a crosslinkable functional group. Examples of the monomer having a crosslinkable functional group include a hydroxyl group-containing monomer and a carboxyl group-containing monomer. Especially, it is preferable to contain a hydroxyl-group containing monomer as a copolymerization component of a base polymer. The hydroxyl group and the carboxyl group of the base polymer serve as a reaction point with the crosslinking agent described later. When the crosslinked structure is introduced into the base polymer, cohesive force is improved, the adhesiveness of the pressure-sensitive adhesive layer is improved, and the fluidity of the pressure-sensitive adhesive is lowered, so the adhesive residue on the adherend at the time of rework tends to be reduced.

As the hydroxyl group-containing monomer, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 4-hydroxybutyl, (meth)acrylic acid 6-hydroxyhexyl, (meth)acrylic acid 8 -hydroxyoctyl, (meth)acrylic acid 10-hydroxydecyl, (meth)acrylic acid 12-hydroxylauryl, (meth)acrylic acid 4-(hydroxymethyl)cyclohexyl)methyl, etc. are mentioned.

Examples of the carboxyl group-containing monomer include (meth)acrylic acid, (meth)acrylic acid 2-carboxyethyl, carboxypentyl (meth)acrylic acid carboxypentyl, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

In the acrylic polymer, the total amount of the hydroxyl group-containing monomer and the carboxyl group-containing monomer with respect to the total amount of the constituent monomer components (100 wt%) is preferably 1 to 30 wt%, more preferably 3 to 25 wt%, and 5 to 20 wt% It is more preferable that it is weight %. In particular, it is preferable that content of the (meth)acrylic acid ester containing a hydroxyl group is the said range.

Acrylic polymer is a constituent monomer component, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole. It is preferable to contain nitrogen-containing monomers, such as vinyl morpholine, N-acryloyl morpholine, N-vinyl carboxylic acid amides, and N-vinyl caprolactam. Since the acrylic polymer containing a nitrogen-containing monomer component exhibits moderate water absorption in a moist heat environment and local absorption of the pressure-sensitive adhesive is suppressed, it contributes to the prevention of local whitening, local swelling, peeling, and the like of the pressure-sensitive adhesive layer.

The content of the nitrogen-containing monomer with respect to the total amount of the constituent monomer components (100 wt%) of the acrylic polymer is preferably 1 to 30 wt%, more preferably 3 to 25 wt%, and 5 to 20 wt% more preferably. It is particularly preferable that the acrylic polymer contains N-vinylpyrrolidone within the above range as a nitrogen-containing monomer.

The acrylic polymer preferably contains a hydroxyl group-containing monomer and a nitrogen-containing monomer as monomer components. When the acrylic polymer contains both a hydroxyl group-containing monomer and a nitrogen-containing monomer as a monomer component, the cohesive force and transparency of the pressure-sensitive adhesive tend to increase. The acrylic polymer is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, more preferably 15 to 35% by weight of the total amount of the hydroxyl group-containing monomer and the nitrogen-containing monomer with respect to the total amount of the constituent monomer components (100% by weight). It is more preferable that it is weight %.

The acrylic polymer may contain monomer components (other monomer components) other than the above. The acrylic polymer may contain, as a monomer component, for example, a cyano group-containing monomer, a vinyl ester monomer, an aromatic vinyl monomer, an epoxy group-containing monomer, a vinyl ether monomer, a sulfo group-containing monomer, a phosphoric acid group-containing monomer, an acid anhydride group-containing monomer, and the like. . The content of these other monomer components is preferably 0 to 40% by weight, more preferably 0 to 30% by weight, still more preferably 0 to 20% by weight with respect to the total amount (100% by weight) of the constituent monomer components. do.

In one embodiment of the present invention, the acrylic polymer is a monomer component and contains 40 to 99% by weight of the (meth)acrylic acid alkylester monomer (preferably 50 to 97% by weight) based on the total amount (100% by weight) of the constituent monomer components. %, more preferably 55 to 95% by weight), 1 to 30 weights of the monomer having a crosslinkable functional group (preferably the hydroxyl group-containing monomer and/or the carboxyl group-containing monomer, more preferably the hydroxyl group-containing monomer) % (preferably 3 to 25% by weight, more preferably 5 to 20% by weight), 1 to 30% by weight of the nitrogen-containing monomer (preferably 3 to 25% by weight, more preferably 5 to 20% by weight) %) included.

The adhesive strength of the pressure-sensitive adhesive layer before curing is likely to depend on the constituent components and molecular weight of the base polymer. From a viewpoint of making suitable adhesiveness and rework property compatible, 100,000-5 million are preferable, as for the weight average molecular weight of an acrylic polymer, 300,000-3 million are more preferable, 500,000-2 million are still more preferable. In addition, when a crosslinked structure is introduce|transduced into a base polymer, the molecular weight of a base polymer refers to the molecular weight before crosslinked structure introduction. The weight average molecular weight of the acrylic polymer can be measured using gel permeation chromatography (GPC).

There exists a tendency for an adhesive to become hard, so that there is much content of the high Tg monomer component in the structural component of a base polymer. In addition, a high Tg monomer means a monomer with a high glass transition temperature (Tg) of a homopolymer. As a monomer whose Tg of a homopolymer is 40 degreeC or more, dicyclopentanyl methacrylate (Tg: 175 degreeC), dicyclopentanyl acrylate (Tg: 120 degreeC), isobornyl methacrylate (Tg: 173 degreeC), iso Bornyl acrylate (Tg: 97 °C), methyl methacrylate (Tg: 105 °C), 1-adamantyl methacrylate (Tg: 250 °C), 1-adamantyl acrylate (Tg: 153 °C) (meth)acrylic monomers such as; Acryloylmorpholine (Tg: 145°C), dimethylacrylamide (Tg: 119°C), diethylacrylamide (Tg: 81°C), dimethylaminopropylacrylamide (Tg: 134°C), isopropylacrylamide ( amide group-containing vinyl monomers such as Tg: 134° C.) and hydroxyethyl acrylamide (Tg: 98° C.); N-vinylpyrrolidone (Tg: 54 degreeC) etc. are mentioned.

It is preferable that content of the monomer whose Tg of a homopolymer is 40 degreeC or more of an acryl-type polymer is 5 to 50 weight% with respect to the total amount of structural monomer components, and, as for the acrylic polymer, it is more preferable that it is 10 to 40 weight%. In order to form a pressure-sensitive adhesive layer having suitable hardness and excellent reworkability, as a monomer component of the base polymer, it is preferable to include a monomer component having a Tg of the homopolymer of 80°C or higher, and a monomer component having a Tg of 100°C or higher of the homopolymer. It is more preferable to include In the acrylic polymer, the content of the monomer having a Tg of 100° C. or higher with respect to the total amount of the constituent monomer components is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, 3 It is especially preferable that it is weight % or more. In particular, it is preferable that content of methyl methacrylate is the said range.

An acrylic polymer as a base polymer is obtained by superposing|polymerizing the said monomer component by various well-known methods, such as solution polymerization, emulsion polymerization, and bulk polymerization. From viewpoints of balance of characteristics, such as the adhesive force of an adhesive and holding|maintenance force, cost, etc., the solution polymerization method is preferable. As a solvent for solution polymerization, ethyl acetate, toluene, etc. are used. The solution concentration is usually about 20 to 80% by weight. As a polymerization initiator, various well-known things, such as an azo type and a peroxide type, can be used. In order to adjust molecular weight, a chain transfer agent may be used. The reaction temperature is usually about 50 to 80°C, and the reaction time is usually about 1 to 8 hours.

(crosslinking agent)

From the viewpoint of giving the pressure-sensitive adhesive a suitable cohesive force, it is preferable that a crosslinked structure is introduced into the base polymer. For example, a crosslinking structure is introduced into a base polymer by adding a crosslinking agent to the solution after polymerization of a base polymer, and heating as needed. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an oxazoline type crosslinking agent, an aziridine type crosslinking agent, a carbodiimide type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned. These crosslinking agents react with functional groups such as hydroxyl groups introduced into the base polymer to form a crosslinked structure.

As a crosslinking agent, the polyisocyanate which has two or more isocyanate groups in 1 molecule is preferable. Examples of the polyisocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; Trimethylolpropane/tolylene diisocyanate trimer adduct (e.g., dosing agent "Coronate L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (e.g., dosing agent "Coronate HL") , a trimethylolpropane adduct of xylylene diisocyanate (for example, "Takenate D110N" manufactured by Mitsui Chemicals), an isocyanurate body of hexamethylene diisocyanate (for example, "Coronate HX" manufactured by Tosoh), etc. of isocyanate adducts, and the like.

One type of crosslinking agent may be used alone or two or more types may be selected.

The amount of the crosslinking agent to be used may be appropriately adjusted according to the composition or molecular weight of the base polymer. The amount of the crosslinking agent used is about 0.1 to 10 parts by weight based on 100 parts by weight of the base polymer before crosslinking, preferably 0.3 to 7 parts by weight, more preferably 0.5 to 5 parts by weight, and still more preferably 1 to 4 parts by weight. . By making the usage-amount of a crosslinking agent larger than the general acrylic transparent adhesive for optics, there exists a tendency for rework property to improve.

In order to promote formation of a crosslinked structure, a crosslinking catalyst may be used. Examples of the cross-linking catalyst include metal-based cross-linking catalysts (especially tin-based cross-linking catalysts) such as tetra-n-butyl titanate, tetraisopropyl titanate, nashem ferric, butyl tin oxide, and dioctyl tin dilaurate. . The amount of the crosslinking catalyst used is generally 0.05 parts by weight or less based on 100 parts by weight of the base polymer.

By introducing the crosslinked structure into the base polymer, the gel fraction rises. The higher the gel fraction, the harder the pressure-sensitive adhesive, and at the time of peeling of the laminate from the adherend by rework or the like, the adhesive residue on the adherend tends to be suppressed. 30 % or more is preferable, as for the gel fraction of the adhesive layer before photocuring, 50 % or more is more preferable, 60 % or more is still more preferable, 65 % or more is especially preferable. 70% or more or 75% or more of the gel fraction before photocuring of an adhesive layer may be sufficient.

Since the adhesive layer contains an unreacted photocuring agent, the gel fraction of the adhesive layer before photocuring is generally 90 % or less. When the gel fraction of the pressure-sensitive adhesive layer before photocuring is excessively large, the anchoring force to the adherend may decrease and the initial adhesive force may become insufficient. Therefore, 85 % or less is preferable and, as for the gel fraction of the adhesive layer before photocuring, 80 % or less is more preferable.

A gel fraction can be calculated|required as an insoluble content with respect to solvent, such as ethyl acetate, and specifically, the weight fraction of the insoluble component after immersing an adhesive layer in ethyl acetate at 23 degreeC for 7 days with respect to the sample before immersion (unit: weight%) ) is obtained as In general, the gel fraction of a polymer is equal to the degree of crosslinking, and the more crosslinked portions in the polymer, the greater the gel fraction. Also, the larger the amount of the photocuring agent, the smaller the gel fraction.

(photocuring agent)

When the pressure-sensitive adhesive layer containing the photocuring agent is photocured after bonding to the adherend, the frictional force increases and the adhesive force with the adherend is improved.

As the photocuring agent, a photocurable monomer or photocurable oligomer is used. As a photocuring agent, the compound which has two or more ethylenically unsaturated bonds in 1 molecule is preferable. In addition, the photocuring agent is preferably a compound exhibiting compatibility with the base polymer. From the viewpoint of showing suitable compatibility with the base polymer, the photocuring agent is preferably a liquid at room temperature. When the photocuring agent is compatible with the base polymer and is uniformly dispersed in the composition, a contact area with the adherend can be secured, and a pressure-sensitive adhesive layer with high transparency can be formed.

By controlling the compatibility of the base polymer and the photocuring agent, a small amount of the photocuring agent bleeds out on the surface of the pressure-sensitive adhesive layer, forming a Weak Boundary Layer (WBL) at the adhesion interface with the adherend. have. When the WBL is formed, the properties of the surface (adhesive interface) are changed while maintaining the bulk properties of the pressure-sensitive adhesive layer. That is, when the WBL is formed, the pressure-sensitive adhesive layer maintains hardness and the frequency dependence of the frictional force and frictional force becomes small, so that peeling at the time of rework becomes easy, and the adhesive residue on the adherend can be reduced. After the photocuring, the photocuring agent reacts, and the WBL disappears or the thickness of the WBL becomes thin, so that the adhesion is improved. Thereby, the outstanding rework property before photocuring and the outstanding adhesiveness (peel durability) after photocuring can be achieved.

The compatibility of the base polymer and the photocuring agent is mainly affected by the structure of the compound. The structure and compatibility of the compound can be evaluated by, for example, Hansen solubility parameters, and the smaller the difference between the solubility parameters of the base polymer and the photocuring agent, the higher the compatibility tends to be.

It is preferable to use a polyfunctional (meth)acrylate as a photocuring agent at a point with high compatibility with the acrylic polymer as a base polymer. Examples of the polyfunctional (meth)acrylate include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and bisphenol A ethylene oxide-modified di(meth)acryl. rate, bisphenol A propylene oxide modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, penta Erythitol tri(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acryl rate, pentaerythol tetra (meth) acrylate, dipentaerythol poly (meth) acrylate, dipentaerythol hexa (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylic a rate, urethane (meth)acrylate, epoxy (meth)acrylate, butadiene (meth)acrylate, isoprene (meth)acrylate, etc. are mentioned.

A photocuring agent may be used individually or by selecting two or more types.

The compatibility of the base polymer and the photocuring agent also depends on the molecular weight of the compound. The lower the molecular weight of the photocuring agent compound, the higher the compatibility with the base polymer tends to be. From a viewpoint of compatibility with a base polymer, 1,500 or less are preferable and, as for the molecular weight of a photocuring agent, 1,000 or less are more preferable.

The type or content of the photocuring agent mainly affects the adhesive strength after photocuring. The adhesive force after photocuring tends to become large, so that the functional group equivalent is small (that is, the functional group number per unit molecular weight is large) and content of a photocuring agent is large.

From a viewpoint of raising the adhesive force after photocuring, 500 or less are preferable and, as for the functional group equivalent (g/eq) of a photocuring agent, 450 or less are more preferable. On the other hand, when the photocrosslinking density is excessively increased, the viscosity of the pressure-sensitive adhesive may be lowered and the adhesive force may be lowered. Therefore, 100 or more are preferable, as for the functional group equivalent of a photocuring agent, 130 or more are more preferable, 150 or more are still more preferable, and 180 or more are especially preferable.

In the combination of the acrylic polymer as the base polymer and the polyfunctional acrylate as the photocuring agent, when the functional group equivalent of the photocuring agent is small, the interaction between the base polymer and the photocuring agent is strong, and the initial adhesive strength tends to increase. In the use of this invention, an excessive raise of initial stage adhesive force may lead to the fall of rework property. It is preferable that the functional group equivalent of a photocuring agent exists in the said range also from a viewpoint of maintaining the adhesive force of the adhesive layer before photocuring and to-be-adhered body in an appropriate range.

1-50 weight part is preferable with respect to 100 weight part of base polymers, as for content of the photocuring agent in an adhesive composition, 5-40 weight part is more preferable, 10-35 weight part is still more preferable. In order to contain a photocuring agent in an uncured state in an adhesive layer, it is preferable to add a photocuring agent to the polymer solution after superposition|polymerization of a base polymer.

When the content of the photocuring agent increases, the photocuring agent tends to bleed out on the surface. The photocuring agent bleed out on the surface forms WBL, contributing to a decrease in the frictional force of the pressure-sensitive adhesive layer. In connection with this, it is possible to appropriately reduce the adhesive force with the adherend, and the reworkability tends to be improved. On the other hand, when a photocuring agent bleeds out in large quantities, the fall of transparency and the fall of adhesive force may be caused. From this point of view, it is preferable to control the amount of the photocuring agent in the above range.

(Photoinitiator)

The photopolymerization initiator generates active species by irradiation with energetic actinic rays, and accelerates the curing reaction of the photocuring agent. The photoinitiator is not particularly limited as long as the molar extinction coefficient at a wavelength of 380 nm is 15 [Lmol ^-1 cm ^{-1 ] or more.} The molar extinction coefficient in a wavelength of 380 nm can be measured for a photoinitiator using a light absorber. The photoinitiator has a molar extinction coefficient at a wavelength of 380 nm, preferably 20 [Lmol ^-1 cm ^-1 ] or more, more preferably 25 [Lmol ^-1 cm ^-1 ] or more. Although the upper limit in particular of the molar extinction coefficient in the wavelength of 380 nm of a photoinitiator is not restrict|limited, For example, it is 1000 [Lmol ^-1 cm ^-1 ] or less.

In the polarizing plate of this invention, in order to suppress deterioration, such as a polarizer by incident of an ultraviolet light, the ultraviolet absorber is contained. When an energy actinic ray is irradiated to the laminate of the polarizing plate and the pressure-sensitive adhesive layer to which such ultraviolet absorption ability is imparted, light having a wavelength shorter than 380 nm is absorbed by the ultraviolet absorber and reaching the pressure-sensitive adhesive layer is suppressed, so that the curing reaction is usually difficult to proceed. However, in the present invention, by using a photoinitiator having a specific molar extinction coefficient, the curing reaction of the photocuring agent can be accelerated even when the ultraviolet absorber is contained in the polarizing plate. Thereby, the adhesive force between the to-be-adhered body of the adhesive layer after photocuring increases, and long-term adhesiveness (peel durability) improves.

As a photoinitiator, the initiator with absorption in a long wavelength region is preferable, For example, an oxime type compound, a metallocene type compound, an acylphosphine type compound, and an aminoacetophenone compound are mentioned. Among them, an acylphosphine-based compound and an oxime-based compound are preferable from the viewpoint of a broad absorption characteristic (especially a large extinction coefficient of 380 nm or more).

As an oxime type compound, the compound of Unexamined-Japanese-Patent No. 2001-233842, the compound of Unexamined-Japanese-Patent No. 2000-80068, the compound of Unexamined-Japanese-Patent No. 2006-342166, J.C.S. Perkin II (1979) pp.1653-1660, J.C.S. Compounds described in each document of Perkin II (1979) pp.156-162, Journal of Photopolymer Science and Technology (1995) pp.202-232, Japanese Patent Laid-Open No. 2000-66385, Japanese Patent Laid-Open No. 2000- 80068, Japanese Patent Publication Nos. 2004-534797, Japanese Unexamined Patent Publication Nos. 2006-342166, WO2015/36910, WO2017/146152 Paragraph Nos. 0154 to 0156 of publications The compounds described in each publication, etc. can be used can

In addition, the compound described in Japanese Patent Publication No. 2009-519904 in which an oxime is linked to the N position of the carbazole ring, a compound described in US Patent No. 7626957 in which a hetero substituent is introduced at the benzophenone moiety, a nitro group is introduced in the dye moiety A compound described in the specification of Japanese Patent Application Laid-Open No. 2010-15025 and US Patent Application Publication No. 2009-292039, a ketoxime compound described in International Publication No. WO2009-131189, a U.S. Patent containing a triazine skeleton and an oxime skeleton in the same molecule You may use the compound described in the specification of 7556910, the compound of Unexamined-Japanese-Patent No. 2009-221114, etc. which have an absorption maxima at 405 nm and have favorable sensitivity with respect to a g-ray light source.

Moreover, the cyclic oxime type compound described in Unexamined-Japanese-Patent No. 2007-231000 and Unexamined-Japanese-Patent No. 2007-322744 can also be used suitably. Among the cyclic oxime compounds, the cyclic oxime compounds condensed with a carbazole dye described in JP-A-2010-32985 and JP-A-2010-185072 have high light absorption properties and are highly sensitive. preferred in

In addition, the compound which has an unsaturated bond at the specific site|part of an oxime type compound (For example, the compound described in Unexamined-Japanese-Patent No. 2009-242469), the oxime type compound which has a fluorine atom (For example, Unexamined-Japanese-Patent No. 2010) - Compounds described in Japanese Patent Application Laid-Open No. 262028, compounds 24 and 36-40 described in Paragraph No. 0345 of Japanese Unexamined Patent Publication No. 2014-500852, Paragraph No. 0101 of Japanese Unexamined Patent Publication No. 2013-164471, compounds (C-3) and the like).

Especially, as a preferable oxime type compound, an oxime ester type is mentioned.

A commercial item may be used for an oxime type compound. As a commercial item, IRGACURE OXE-01 (made by BASF), IRGACURE OXE-02 (made by BASF)---, TR-PBG-304 (made by Changzhou Kyoryoku Shin-Iryo Co., Ltd.)--, DFI-091, as a commercial item, for example. (Dytokemix Co., Ltd. product) etc. can be used.

As a metallocene type compound, Unexamined-Japanese-Patent No. 59-152396, Unexamined-Japanese-Patent No. 61-151197, Unexamined-Japanese-Patent No. 63-41484, Unexamined-Japanese-Patent No. 2-249, JP, for example. The titanocene compound described in Paragraph Nos. 0159 to 0153 of Unexamined Patent Application Publication Nos. 2-291, Hei 2-4705, and WO2017/146152; and the iron-arene complex described in Publication No. 1-152109.

As a metallocene type compound, a commercial item can be used. For example, as bis(methylcyclopentadienyl)-Ti-bis(2,6-difluorophenyl), IRGACURE-727 (made by BASF) etc. are mentioned, Bis(cyclopentadienyl)-bis Examples of (2,6-difluoro-3-(pyri-1-yl)phenyl)titanium include IRGACURE-784 (manufactured by BASF).

Examples of the acylphosphine-based compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. Moreover, the acylphosphine oxide type|system|group initiator described in Japanese Patent No. 4225898 can also be used.

As an acylphosphine-type compound, a commercial item can be used. For example, commercially available Omnirad-819 or Omnirad-TPO (trade names: all made by IGM Japan) can be used.

As an aminoacetophenone compound, the compound of Unexamined-Japanese-Patent No. 10-291969 can be used, for example. Moreover, as an aminoacetophenone type compound, the compound described in Unexamined-Japanese-Patent No. 2009-191179 in which the maximum absorption wavelength was matched to the long-wave region, such as 365 nm or 405 nm, can also be used.

Among these, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one is mentioned as a preferable aminoacetophenone compound.

As an aminoacetophenone compound, a commercial item can be used. For example, commercial items Omnirad-907, Omnirad-369, and Omnirad-379 (trade names: all made by IGM Japan) can be used.

A photoinitiator may be used independently and may mix and use 2 or more types.

0.01-3 weight part is preferable with respect to 100 weight part of base polymers, as for content of the photoinitiator in an adhesive composition, 0.02-1 weight part is more preferable, 0.04-0.5 weight part is still more preferable. From the viewpoint of suppressing the change in the adhesive strength of the pressure-sensitive adhesive layer over time when storing the laminate for a long period of time or storing the laminate in a state before photocuring after bonding with the adherend, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition is 3 parts by weight or less. Preferably, 1 part by weight or less is more preferable, and 0.5 part by weight or less is still more preferable. From a viewpoint of fully advancing photocuring by ultraviolet irradiation etc. and improving adhesion reliability, 0.01 weight part or more is preferable and, as for content of the photoinitiator in an adhesive composition, 0.02 weight part or more is more preferable.

(sensitizer)

The pressure-sensitive adhesive composition may also contain a sensitizer. By using a photoinitiator and a sensitizer together, the reaction rate of a photocuring reaction can be slowed down. Therefore, even when stored under visible light irradiation such as a fluorescent lamp after bonding, the initial adhesive force is kept low, and a laminate excellent in reworkability is obtained.

Although a sensitizer in particular is not restrict|limited, For example, the compound represented by the following general formula (e1) is mentioned.

(wherein, R ¹ and R ² each independently represent -H, -CH ₃ , -CH ₂ CH ₃ , -CH(CH ₃ ) ₂ or Cl, and R ¹ and R ² may be the same or different)

Among them, R ¹ and R ² is -CH ₂ CH ₃ of diethyl thioxanthone is particularly preferred.

A sensitizer may be used independently and may mix and use 2 or more types.

0.001-10 weight part is preferable with respect to 100 weight part of base polymers, and, as for content of the sensitizer in an adhesive composition, 0.01-5 weight part is more preferable.

(Other additives)

In addition to each component exemplified above, the pressure-sensitive adhesive composition contains additives such as a silane coupling agent, a tackifier, a plasticizer, a softener, an anti-degradation agent, a filler, a colorant, an ultraviolet absorber, an antioxidant, a surfactant, an antistatic agent, and the like, the properties of the present invention You may contain it in the range which does not impair.

<Use of laminated body>

The laminate of the said embodiment can be used as an optical film laminated|stacked with the other optical layer on a polarizing plate at the time of practical use. That is, according to one Embodiment of this invention, the optical film containing the laminated body of the said embodiment is provided.

Although there is no limitation in particular about an optical layer, For example, used for formation of liquid crystal display devices, such as a reflective plate, a transflective plate, retardation plate (including a wave plate of 1/2 or 1/4 etc.), a visual compensation film, etc. One or two or more optical layers may be used. In particular, in the laminate of the above embodiment, a reflective polarizing plate or a transflective polarizing plate in which a reflective plate or a transflective plate is further laminated on a polarizing plate, or an elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate, the polarizing plate also visually A wide viewing angle polarizing plate in which a compensation film is laminated, or a polarizing plate in which a brightness improving film is further laminated on the polarizing plate is preferable.

The optical film in which the optical layer is laminated on the polarizing plate in the laminate can also be formed by sequentially and separately laminated in the manufacturing process of a liquid crystal display device etc. There is an advantage in that the manufacturing process of the liquid crystal display device and the like can be improved due to excellent assembly work and the like. The same adhesive as the adhesive layer which comprises a laminated body may be used for lamination|stacking of an optical layer, and other commonly used bonding means may be used. For example, an adhesive having, as a base polymer, an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based polymer or a rubber-based polymer can be appropriately selected and used.

The laminate or optical film of the said embodiment can be used suitably for various image display apparatuses, such as a liquid crystal display device. That is, according to one Embodiment of this invention, the image display apparatus containing the laminated body of the said embodiment is provided. As an image display apparatus, a liquid crystal display device, an organic electroluminescent display, etc. are mentioned, for example.

<Production of laminated body>

The laminate may be formed by laminating a pressure-sensitive adhesive layer on the surface of the polarizing plate. The pressure-sensitive adhesive layer may use a direct method formed on a polarizing plate, or a transfer method in which a pressure-sensitive adhesive layer formed in a sheet shape on a peelable surface (peelable surface) is transferred onto a polarizing plate, or a combination of these methods may be used. . As said release surface, the surface of a release liner, the back surface of the base material by which the release process was carried out, etc. can be used. It is good also considering the base material which has a peeling surface used for formation of an adhesive layer as a separator as it is.

For example, a pressure-sensitive adhesive composition comprising a base polymer, a photocuring agent and a photopolymerization initiator, and, if necessary, a sensitizer, other additives and solvents, on a polarizing plate or a substrate, roll coating, kiss roll coating, gravure coating, reverse coating, The pressure-sensitive adhesive layer is formed by applying by roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coating, etc., and drying off the solvent as necessary. As the drying method, an appropriately suitable method can be adopted. The heat drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, still more preferably 70°C to 170°C. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, still more preferably 10 seconds to 10 minutes.

When an adhesive composition contains a crosslinking agent, it is preferable to advance bridge|crosslinking by a heating or aging after drying of a solvent or simultaneous with drying of a solvent. Heating temperature and heating time are suitably set according to the kind of crosslinking agent to be used, and bridge|crosslinking is performed by heating for about 1 minute - about 7 days in the range of 20 degreeC - 160 degreeC normally. Heating for drying and removing the solvent may also serve as heating for crosslinking.

Even after the crosslinking structure is introduced into the polymer by the crosslinking agent, the photocuring agent maintains an unreacted state. Therefore, the photocurable adhesive layer containing a base polymer and a photocuring agent is formed.

When forming the pressure-sensitive adhesive' layer on the polarizing plate, it is preferable to lay a separator on the pressure-sensitive adhesive layer for the purpose of protection of the pressure-sensitive adhesive layer or the like. You may bridge|crosslink after laying a separator on an adhesive layer.

<Photocuring of the adhesive layer>

After bonding a laminated body to a to-be-adhered body, an adhesive layer is photocured by irradiating an energy actinic ray to an adhesive layer. As for the laminated body of this invention, an adhesive layer is photocurable, and the timing of hardening can be set arbitrarily. Since processing such as rework and processing can be performed at any timing from the time the laminate is attached to the adherend to the photocuring of the adhesive, it is possible to respond flexibly to the lead time of the device manufacturing process. .

Examples of the energetic actinic rays include ultraviolet rays, visible light, infrared rays, X-rays, α-rays, β-rays, and γ-rays. Since hardening of the adhesive layer in a storage state can be suppressed and hardening of an adhesive layer can be made easy, as an energy actinic ray, the energy actinic ray of the wavelength range of 380 nm or more and 450 nm or less is preferable. By using an energy actinic ray having a longer wavelength than ultraviolet (wavelength less than 380 nm), even when a polarizing plate containing a ultraviolet absorber is used, the photocuring reaction by the polymerization initiator is accelerated, and the function of the pressure-sensitive adhesive by increasing the adhesive force after photocuring is sufficiently improved. can perform

As a light source of energy actinic radiation in the wavelength range of 380 nm or more and 450 nm or less, a gallium-encapsulated metal halide lamp and the LED light source which light-emits 380-440 nm in wavelength range are preferable. Alternatively, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, an incandescent bulb, a xenon lamp, a halogen lamp, a carbon arc lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a gallium lamp, an excimer laser or sunlight as a light source, It is also possible to use a pass filter to block light with a wavelength shorter than 380 nm.

What is necessary is just to set the irradiation intensity and irradiation time of an energy actinic ray suitably according to the composition, thickness, etc. of an adhesive layer. From the viewpoint of peel strength (adhesiveness), the irradiation amount of energy actinic ray in the wavelength range of 380 nm or more and 450 nm or less is preferably 1,000 mJ/cm ² or more, more preferably 2,000 mJ/cm ² or more, still more preferably 3,000 mJ/cm ² or more. Moreover, from the viewpoint of deterioration of polarizing plate etc., the irradiation amount of this energy actinic ray becomes like this. Preferably it is 50,000 J/cm ² or less, More preferably, it is 30,000 J/cm ² or less, More preferably, it is 10,000 J/cm ² or less. am. The active energy line irradiation dose, is for example 1,000 to 50,000mJ / cm ² range, or the range of 1,000 to 30,000mJ / cm ^2, or from 2,000 to the range of 30,000mJ / cm ^2.

The to-be-adhered body to which a laminated body is bonded is not specifically limited, Various electronic devices which require a polarizing plate, an optical device, its constituent parts, etc. are mentioned. The adherend is, for example, a panel (eg, a liquid crystal panel or an organic EL panel). The laminate may be bonded to the entire surface of the adherend, or may be selectively bonded to only a portion. In addition, after bonding a laminated body to the whole surface of a to-be-adhered body, you may cut|disconnect the laminated body in the location which is not required, and may peel and remove. Before photocuring, since the laminate is in a state of being temporarily adhered to the surface of the adherend, the laminate can be easily peeled off from the surface of the adherend.

One embodiment of the present invention relates to a method of manufacturing an image display device. The manufacturing method includes disposing a laminate through the pressure-sensitive adhesive layer on a panel, and curing the pressure-sensitive adhesive layer by irradiating the pressure-sensitive adhesive layer with energy actinic rays in a wavelength range of 380 nm to 450 nm.

The irradiation direction of the energy actinic ray is not particularly limited, but since it is usually difficult for the panel to transmit light through wiring or the like, it is preferable to irradiate from the polarizing plate side. In this invention, deterioration of a polarizer at the time of irradiating an energy actinic ray is suppressed by a polarizing plate containing a ultraviolet absorber. In addition, by using a photoinitiator having a specific molar extinction coefficient, the curing reaction of the photocuring agent can be accelerated even when an energy actinic ray is irradiated through a polarizing plate to which ultraviolet absorption ability is imparted, and the adhesiveness of the adherend of the pressure-sensitive adhesive layer can be improved. .

Example

Hereinafter, the present invention will be described in detail with reference to Examples, but the technical scope of the present invention is not limited thereto. In addition, unless otherwise noted, all parts and % in each example are based on weight. All room temperature leaving conditions not specifically prescribed|regulated below are 23 degreeC and 65%RH.

In addition, the measurement of each physical property was performed by the following method.

<Weight Average Molecular Weight>

The weight average molecular weight (in terms of polystyrene) of the base polymer was measured under the following conditions using GPC ("HLC-8220GPC" manufactured by Tosho).

Sample concentration: 0.2% by weight (tetrahydrofuran solution)

Sample injection volume: 10 μl

Eluent: THF

Flow rate: 0.6ml/min

Measuring temperature: 40℃

Sample column: TSKguardcolumn SuperHZ-H (1 pc.) +TSKgel SuperHZM-H (2 pc.)

Reference column: TSKgel SuperH-RC (1 pc.)

Detector: RI

<Light transmittance of 380 nm>

Measurement was made using a spectrophotometer (manufactured by Shimadzu Corporation, UV2450).

[Polymerization of acrylic polymer]

<Polymer A1>

In a reaction vessel equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, as a monomer, 63 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinylpyrrolidone (NVP), and methyl meta 9 parts by weight of acrylate (MMA) and 13 parts by weight of hydroxyethyl acrylate (HEA), 0.2 parts by weight of azobisisobutyronitrile as a polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent were added, and nitrogen gas was flowed to , nitrogen substitution was performed for about 1 hour while stirring. Then, it heated at 60 degreeC, made it react for 7 hours, and obtained the solution of the acrylic polymer (polymer A) whose weight average molecular weight (Mw) is 1.2 million.

[Preparation of adhesive composition]

<Adhesive Compositions 1 to 8>

To the solution of the acrylic polymer, a photocuring agent, a crosslinking agent, and, if necessary, a photoinitiator and a sensitizer were added and mixed uniformly to prepare a pressure-sensitive adhesive composition having a composition shown in Table 1 below. In addition, the addition amount in Table 1 is the addition amount (weight part of solid content) with respect to 100 weight part of acrylic polymers. The details of the photoinitiator, photocuring agent, crosslinking agent, and sensitizer used are as follows.

(crosslinking agent)

B1: Takenate D110N (75% ethyl acetate solution of trimethylolpropane adduct of xylylene diisocyanate; manufactured by Mitsui Chemicals)

(Photoinitiator)

C1: Omnirad819 (Acylphosphine-based compound: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; manufactured by IGM Japan)

C2: Omnirad907 (aminoacetophenone-based compound; 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one; manufactured by IGM Japan)

C3: Omnirad184 (1-hydroxycyclohexylphenyl ketone; manufactured by IGM Japan)

(photocuring agent)

D1: APG700 (polypropylene glycol #700 (n=12) diacrylate; functional group equivalent 404 g/eq)

(sensitizer)

E1: KAYACURE DETX-S (diethyl thioxanthone; manufactured by Nippon Kayaku Co., Ltd.)

[Production of polarizing film]

<Polarizing film 1>

A polyvinyl alcohol (PVA) film having a thickness of 80 µm (average degree of polymerization: 2400, degree of saponification: 99.9 mol%) is dyed up to three times in an iodine solution of 0.3% concentration at 30°C for 1 minute between rolls with different speed ratios. was stretched. Then, it extended|stretched to the overall draw ratio 6 times, immersing in the aqueous solution containing 60 degreeC 4% concentration of boric acid and 10% concentration of potassium iodide for 0.5 minute after that. Then, after wash|cleaning by immersing for 10 second in the aqueous solution containing potassium iodide of 30 degreeC 1.5% density|concentration, it dried at 50 degreeC for 4 minutes, and obtained the 25-micrometer-thick polarizer.

A PVA-based resin aqueous solution is applied to both surfaces of the polarizer, an acrylic resin film with a thickness of 30 μm is applied to one side, and a triacetyl cellulose (TAC)-based film (containing a UV absorber) having a thickness of 40 μm is bonded to the other side. Polarizing film 1 was produced. In the obtained polarizing film 1, the light transmittance in 380 nm was 2.5 %.

[Production of cross-linked and laminated body]

Examples 1 to 6, Comparative Examples 1 to 2 (laminated bodies 1 to 8)

The pressure-sensitive adhesive composition shown in Table 2 was applied to the release treatment surface of the separator (a polyethylene terephthalate film having a thickness of 25 µm on which the surface was subjected to silicone release treatment) using a fountain roll so that the thickness after drying was set to 25 µm. After drying at 130° C. for 1 minute to remove the solvent, the coated surface of the pressure-sensitive adhesive was bonded onto the acrylic resin film of the polarizing film. Thereafter, an aging treatment was performed for 4 days in an atmosphere of 25°C, crosslinking was advanced, and a crosslinked structure was introduced into the acrylic polymer as a base polymer. Thereby, the adhesive layer was fixedly laminated on the polarizing film, and the laminated body by which the separator was temporarily adhered was obtained on it.

Reference Example 1 (Laminate 9)

On a polyethylene terephthalate (PET) film with a thickness of 75 µm that has not been surface-treated ("Lumirer S10" manufactured by Toray Industries, Ltd.), the pressure-sensitive adhesive composition shown in Table 2 was applied to a thickness of 25 µm after drying using a fountain roll. was applied. After drying at 130° C. for 1 minute to remove the solvent, the release-treated surface of a separator (a polyethylene terephthalate film with a thickness of 25 μm, the surface of which has been subjected to silicone release treatment) was bonded to the coated surface of the pressure-sensitive adhesive. Then, the aging process for 4 days was performed in 25 degreeC atmosphere, crosslinking was advanced, the adhesive layer was fixedly laminated on PET film, and the laminated body by which the separator was temporarily adhered was obtained.

The following evaluation was performed about the laminated body obtained in the said Examples 1-6, Comparative Examples 1-2, and Reference Example 1. A result is shown in Table 2.

<Evaluation of adhesive strength>

The separator is peeled and removed from the adhesive surface of a polarizing plate with an adhesive cut out to an alkali-free glass (made by Corning, EagleXG) to a width of 25 mm x a length of 100 mm, and the exposed adhesive surface is bonded to an alkali-free glass using a hand roller, and photocured. It was set as the previous test sample.

What photocured the adhesive layer by irradiating energy actinic ray (light source: LED) from the polarizing plate side of the test sample before photocuring was made into the test sample after photocuring.

Using these test samples before and after photocuring, using a tensile tester (device name: Precision Universal Tester, Autograph AG-IS, manufactured by Shimadzu Corporation), according to JIS Z0237:2009, peeling angle 90°, Under the condition of a tensile rate of 300 mm/min, 90° peel adhesion (adhesive force T1 to alkali-free glass before photocuring and adhesive force T2 to alkali-free glass after photocuring) was measured. The measurement was performed 3 times, the average value was calculated|required, and it showed in the "before photocuring" and "after photocuring" column of "adhesive force with respect to an alkali free glass" of Table 2, respectively. In addition, the increase ratio (=T2/T1) of the adhesive force (T2) to the alkali-free glass after photocuring with respect to the adhesive force (T1) with respect to the alkali-free glass before photocuring is computed, and the column of "increase ratio" of Table 2 shown in

(reworkability)

From the value of the adhesive force of the test sample before photocuring, the rework property was judged by the following reference|standard.

A: 3N/25mm or less

B: More than 3N/25mm 6N/25mm or less

C: More than 6N/25mm 7N/25mm or less

D: more than 7N/25mm

A result is shown in Table 2.

(Adhesiveness)

From the value of the adhesive force of the test sample before and behind photocuring, adhesiveness (peel durability) was judged by the following reference|standard.

A: 8N/25mm or more

B: 5N/25mm or more and less than 8N/25mm

C: less than 5N/25mm

A result is shown in Table 2.

As shown in Table 2, a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive composition comprising a polarizing film including a UV absorber, a base polymer, a photocuring agent, and a ^{photopolymerization initiator having a molar extinction coefficient of 15 [Lmol -1} cm ^{-1 ] or more} It was confirmed that the laminated body (Examples 1-6) of the fruit was excellent in rework property and adhesiveness. In these laminates, it was confirmed that the adhesive force after photocuring is 1.4 times or more before photocuring, and the adhesive force can be increased by photocuring the pressure-sensitive adhesive layer after adhesion to the adherend.

Even when the photoinitiator and the sensitizer were used together (Examples 2 and 3), it was confirmed that the adhesive force after photocuring can be increased (adhesion improvement) while maintaining the low adhesive force (good rework property) before photocuring (adhesion improvement). comparison of Examples 2 and 3 and Example 6).

Due to the difference in the addition amount of the photopolymerization initiator, a difference was seen in the adhesive strength before and after photocuring (comparison between Examples 1 and 4).

Due to the difference in the amount of UV irradiation, there was a difference in the adhesive strength after photocuring (compare Example 1 and Example 5).

On the other hand, in the laminate (comparative example 1) using the adhesive composition 6 containing the photoinitiator whose molar extinction coefficient is less than 15, the raise of the adhesive force by photocuring was not enough, and adhesiveness was not enough.

In the laminate (comparative example 2) using the adhesive composition 8 which does not contain a photocuring agent, the raise of the adhesive force by photocuring was hardly recognized. Moreover, in the comparative example 2, the adhesive force before photocuring was high and it was inferior to rework property. This is presumably because in the laminate of Comparative Example 2, no WBL (adhesion inhibiting layer; brittle layer) was formed at the interface between the pressure-sensitive adhesive layer and the adherend.

The reference example 1 was implemented in order to examine the influence which a polarizing film has on photocuring reaction. When a PET film was used instead of the polarizing film 1 containing the ultraviolet absorber (Reference Example 1), as in Comparative Example 1, even when the pressure-sensitive adhesive composition 6 containing a photopolymerization initiator having a molar extinction coefficient of less than 15 was used, by photocuring It was confirmed that the adhesive force increased. From this, in the photocuring reaction of the adhesive layer laminated|stacked on the polarizing film containing a ultraviolet absorber, it is suggested that the presence of the photoinitiator whose ^{molar extinction coefficient is 15 [Lmol -1} cm ^{-1] or more is important.}

By using a pressure-sensitive adhesive composition containing a photopolymerization initiator having a ^{molar extinction coefficient of 15 [Lmol -1} cm ^-1 ] or more in a polarizing plate containing an ultraviolet absorber, the photocuring reaction of the pressure-sensitive adhesive layer is sufficiently achieved by irradiation with energy actinic rays (UV). It is thought that it progressed and led to the improvement of the adhesive force (adhesion improvement) after hardening.

The laminated body of this invention is used suitably for the polarizing plate with an adhesive layer, the optical film using this, or an image display apparatus.

1: Polarizer
2,2': transparent protective film
3: Polarizer
4: adhesive layer
5: separator
6: Laminate
10: Polarizing film with adhesive layer

Claims (19)

A polarizing plate comprising an ultraviolet absorber, and
having an adhesive layer on at least one surface of the polarizing plate,
The pressure-sensitive adhesive layer is a layer formed of a pressure-sensitive adhesive composition comprising a base polymer, a photocuring agent, and a ^{photopolymerization initiator having a molar extinction coefficient of 15 [Lmol -1} cm ^{-1 ] or more at a wavelength of 380 nm, the laminate.} The laminate according to claim 1, wherein the polarizing plate has a light transmittance of 380 nm of 20% or less. The laminate according to claim 1 or 2, wherein the pressure-sensitive adhesive layer can be cured by irradiation with energy actinic rays in a wavelength range of 380 nm or more and 450 nm or less. The laminate according to any one of claims 1 to 3, wherein the adhesive force after curing of the pressure-sensitive adhesive layer is larger than the adhesive force before curing. The adhesive force before hardening by 90 degree peeling at the speed|rate of 300 mm/min with respect to the alkali free glass of the said adhesive layer is 7 N/25 mm or less, The laminated body of any one of Claims 1-4. The adhesive force after hardening by 90 degree peeling at the speed|rate of 300 mm/min with respect to the alkali free glass of the said adhesive layer is 5 N/25 mm or more, The laminated body of any one of Claims 1-5. The laminate according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive composition further comprises a sensitizer. The laminate according to any one of claims 1 to 7, wherein the photopolymerization initiator comprises at least one selected from the group consisting of an oxime compound, a metallocene compound, an acylphosphine compound, and an aminoacetophenone compound. sifter. According to any one of claims 1 to 8, wherein the ultraviolet absorber is at least selected from the group consisting of a benzophenone-based compound, an oxalic acid anilide-based compound, a cyanoacrylate-based compound, a benzotriazole-based compound, and a triazine-based compound. A laminate comprising one type. The lamination according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive composition comprises 1 to 50 parts by weight of the photocuring agent, and 0.01 to 3 parts by weight of the photopolymerization initiator based on 100 parts by weight of the base polymer. sifter. The laminate according to any one of claims 1 to 10, wherein the base polymer contains an acrylic polymer. The laminate according to claim 11, wherein the acrylic polymer contains a hydroxyl group-containing monomer and a nitrogen-containing monomer as monomer components. The laminate according to any one of claims 1 to 12, wherein the photocuring agent comprises a polyfunctional (meth)acrylate. The laminate according to any one of claims 1 to 13, wherein the polarizing plate has a polarizer and a transparent protective film on at least one surface of the polarizer, and the transparent protective film contains the ultraviolet absorber. The optical film containing the laminated body in any one of Claims 1-14. The image display device containing the laminated body in any one of Claims 1-14. The device of claim 16 , wherein the pressure-sensitive adhesive layer comprises a curing reaction product of the base polymer and the photocuring agent. It is the manufacturing method of the image display apparatus of Claim 16 or 17,
Disposing a laminate through the pressure-sensitive adhesive layer on a panel, and irradiating the pressure-sensitive adhesive layer with energy actinic rays in a wavelength range of 380 nm or more and 450 nm or less to cure the pressure-sensitive adhesive layer. The method according to claim 18, wherein the irradiation amount of the energy actinic ray in the wavelength range of 380 nm or more and 450 nm or less to the pressure-sensitive adhesive layer is 1000 mJ/cm ² or more.

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