KR20210125597A - Ultraviolet-curable acrylic adhesive composition, ultraviolet-curable acrylic adhesive layer, adhesive layer-equipped polarization film, method for producing ultraviolet-curable acrylic adhesive layer, and image display device - Google Patents

Abstract

It is an ultraviolet curable acrylic adhesive composition for forming the adhesive layer located between the cover glass or cover plastic in an image display apparatus, and a polarizing film, The said adhesive composition is a monomer component containing an alkyl (meth)acrylate and/or A partial polymer of the monomer component, an ultraviolet absorber, and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more, wherein the PSA layer formed from the PSA composition has a transmittance of 40% or less at a wavelength of 380 nm Moreover, the transmittance|permeability in wavelength 400nm is 30 % or more, It is an ultraviolet curable acrylic adhesive composition characterized by the above-mentioned.

Description

UV-curable acrylic pressure-sensitive adhesive composition, UV-curable acrylic pressure-sensitive adhesive layer, polarizing film having a pressure-sensitive adhesive layer, UV-curable acrylic pressure-sensitive adhesive layer manufacturing method, and image display device TECHNICAL FIELD [0002] EQUIPPED POLARIZATION FILM, METHOD FOR PRODUCING ULTRAVIOLET-CURABLE ACRYLIC ADHESIVE LAYER, AND IMAGE DISPLAY DEVICE}

This invention relates to the ultraviolet curable acrylic adhesive composition for forming the adhesive layer located between the cover glass or cover plastic in an image display apparatus, and a polarizing film. The present invention also provides an ultraviolet curable acrylic pressure-sensitive adhesive layer formed from the ultraviolet curable acrylic pressure-sensitive adhesive composition, a polarizing film having a pressure-sensitive adhesive layer having the ultraviolet curable acrylic pressure-sensitive adhesive layer, a method for producing the ultraviolet curable acrylic pressure-sensitive adhesive layer, and an image display device is about Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper.

For a liquid crystal display device, an organic EL display device, etc., from the image formation method, for example, in a liquid crystal display device, it is indispensable to arrange|position a polarizing element on both sides of a liquid crystal cell, and a polarizing film is generally adhere|attached. In addition to the polarizing film, various optical elements have been used in display panels such as liquid crystal panels and organic EL panels to improve display quality of displays.

The polarizing film used for these image display apparatuses generally has a structure which clamps a polarizer with two protective films, and triacetyl cellulose (TAC) is widely used as a protective film.

In recent years, with the flow of weight reduction and thinning of an image display apparatus, thin film formation is calculated|required with respect to each member used for an image display apparatus, and thin film formation is calculated|required also about the protective film of a polarizing film. When the thickness of the protective film becomes thin, the ultraviolet rays incident on the image display device cannot be sufficiently cut, and not only the polarizer but also various optical members including liquid crystal panels and organic EL elements used in the image display device are deteriorated by ultraviolet rays. There were problems such as speeding up the

In order to solve such a problem, for example, it is provided between the surface protection panel in an image display device and the visual recognition side of a liquid crystal module, and is a double-sided adhesive sheet for integrating two members, It has at least one ultraviolet-ray absorption layer, , a transparent double-sided adhesive sheet for an image display device having a light transmittance of 30% or less at a wavelength of 380 nm and a visible light transmittance of 80% or more on a longer wavelength side than a wavelength of 430 nm (see, for example, Patent Document 1), and an acrylic polymer And the adhesive sheet which has an adhesive layer containing a triazine type ultraviolet absorber is known (for example, refer patent document 2). Moreover, in the adhesive optical film in which the adhesive layer is provided in the single side|surface or both surfaces of an optical film, it is known that the said adhesive layer can provide ultraviolet-ray absorption (for example, refer patent document 3).

Japanese Patent Laid-Open No. 2012-211305 Japanese Patent Laid-Open No. 2013-75978 Japanese Patent No. 4208187 Publication

In the adhesive sheet of the said patent document 1, 2, since the thickness of the adhesive layer containing a ultraviolet absorber was thin, it was not sufficient as an ultraviolet-ray absorption function. Moreover, since the thickness of an adhesive layer is thin, when uneven (step difference) absorbency is required, problems, such as a defect which generate|occur|produces a bubble generate|occur|produced, may arise. In these patent documents, polymerization by ultraviolet irradiation is not performed in formation of the adhesive layer containing an ultraviolet absorber, and, of course, examination is not made also about the photoinitiator which has an absorption band at wavelength 400nm or more.

Moreover, in patent document 3, using the polymerization method by ultraviolet irradiation, forming the adhesive layer which has an ultraviolet-ray absorption function is not specifically examined at all, It is sufficient also about the photoinitiator which has an absorption band at wavelength 400nm or more. review has not been done.

In addition to Patent Documents 1 to 3, a variety of transparent pressure-sensitive adhesives having a UV-absorbing function are known, but as for the currently known transparent pressure-sensitive adhesives having a UV-absorbing function, the placenta was prepared by solution polymerization of a base polymer of the pressure-sensitive adhesive. In such a manufacturing method, it is difficult to manufacture a 150 micrometer or more thick product, and there existed a limit in the thickness of the adhesive layer which can be manufactured. It is known that a thick pressure-sensitive adhesive layer can be formed when the polymerization method by ultraviolet irradiation is used, but it is currently unknown about a method of forming a pressure-sensitive adhesive layer having an ultraviolet absorption function by the polymerization method by ultraviolet irradiation. situation was.

Then, an object of this invention is to provide the ultraviolet curable acrylic adhesive composition which can form the adhesive layer which has an ultraviolet-ray absorption function by the polymerization method by ultraviolet irradiation. The present invention also provides an ultraviolet curable acrylic pressure-sensitive adhesive layer formed from the ultraviolet curable acrylic pressure-sensitive adhesive composition, a polarizing film having a pressure-sensitive adhesive layer having the ultraviolet curable acrylic pressure-sensitive adhesive layer, a method for producing the ultraviolet curable acrylic pressure-sensitive adhesive layer, and an image display device It is also intended to provide

MEANS TO SOLVE THE PROBLEM As a result of repeating earnest examination to solve the said subject, the present inventors found out the following ultraviolet curable acrylic adhesive composition, and came to complete this invention.

That is, the present invention is an ultraviolet curable acrylic pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer positioned between a cover glass or cover plastic and a polarizing film in an image display device,

The pressure-sensitive adhesive composition comprises a monomer component containing an alkyl (meth) acrylate and/or a partial polymer of the monomer component, a UV absorber, and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more,

Transmittance in wavelength 380nm of the adhesive layer formed from the said adhesive composition is 40% or less, and the transmittance|permeability in wavelength 400nm is 30% or more, It relates to the ultraviolet curable acrylic adhesive composition characterized by the above-mentioned.

It is preferable that the permeation|transmission b* value of the said adhesive layer is 3.0 or less.

At least one ultraviolet absorber selected from the group consisting of a triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule, and a benzotriazole-based ultraviolet absorber having one benzotriazole skeleton in one molecule, wherein the ultraviolet absorber is It is preferable to be

It is preferable that the addition amount of the said photoinitiator (A) is less than the addition amount of the said ultraviolet absorber.

It is preferable to further contain the photoinitiator (B) which has an absorption band in wavelength less than 400 nm in the ultraviolet curable acrylic adhesive composition of this invention.

This invention is the adhesive layer located between the cover glass or cover plastic in an image display apparatus, and a polarizing film,

It relates to an ultraviolet curable acrylic adhesive layer, characterized in that it is formed by irradiating ultraviolet rays to the ultraviolet curable acrylic pressure sensitive adhesive composition to photopolymerize a monomer component in the ultraviolet curable acrylic pressure sensitive adhesive composition.

This invention has a polarizing film and the said ultraviolet curable acrylic adhesive layer on at least one surface of the said polarizing film, It relates to the polarizing film which has an adhesive layer characterized by the above-mentioned.

Further, the present invention is a method for producing a pressure-sensitive adhesive layer formed from an ultraviolet curable acrylic pressure-sensitive adhesive composition containing the photopolymerization initiator (B),

A step of forming a partial polymer of the monomer component by irradiating ultraviolet rays to a composition comprising a monomer component containing an alkyl (meth) acrylate and the photopolymerization initiator (B);

A step of adding an ultraviolet absorber and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more to the partial polymer of the monomer component to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition;

A step of coating the ultraviolet curable acrylic pressure-sensitive adhesive composition on at least one side of a substrate and irradiating the ultraviolet curable acrylic pressure-sensitive adhesive composition with ultraviolet rays

It relates to a method for producing a UV-curable acrylic pressure-sensitive adhesive layer, characterized in that it comprises a.

Moreover, this invention is an image display apparatus which has at least a cover glass or cover plastic, and a polarizing film,

It relates to an image display device characterized in that it has the UV-curable acrylic pressure-sensitive adhesive layer between the cover glass or cover plastic and the polarizing film.

Since the UV-curable acrylic pressure-sensitive adhesive composition of the present invention can form a pressure-sensitive adhesive layer having a UV-absorbing function by a polymerization method by UV irradiation, it is possible to form a thick pressure-sensitive adhesive layer of 150 μm or more, thereby forming a pressure-sensitive adhesive layer with a wide thickness. it can be done Since the adhesive layer of this invention has the outstanding ultraviolet absorption function, deterioration of optical members, including a liquid crystal panel, an organic electroluminescent element, a polarizer, etc. can be suppressed by using the said adhesive layer for an image display device.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically one Embodiment of the image display apparatus of this invention.
2 is a cross-sectional view schematically showing an embodiment of the image display device of the present invention.
It is sectional drawing which shows typically one Embodiment of the image display apparatus of this invention.

1. UV-curable acrylic pressure-sensitive adhesive composition

The ultraviolet curable acrylic adhesive composition of this invention is an ultraviolet curable acrylic adhesive composition for forming the adhesive layer located between the cover glass or cover plastic in an image display apparatus, and a polarizing film,

The pressure-sensitive adhesive composition comprises a monomer component containing an alkyl (meth) acrylate and/or a partial polymer of the monomer component, a UV absorber, and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more,

The transmittance|permeability in wavelength 380nm of the adhesive layer formed from the said adhesive composition is 40 % or less, and the transmittance|permeability in wavelength 400nm is 30 % or more, It is characterized by the above-mentioned.

EMBODIMENT OF THE INVENTION Embodiment of the image display apparatus containing the adhesive layer of this invention is described in detail using drawing. However, this invention is not limited to embodiment of drawing.

As an example of the structure of an image display apparatus, as shown in FIGS. 1-3, for example,

cover glass or cover plastic (1)/adhesive layer (2a)/polarizing film (5)/liquid crystal display (LCD) or organic EL display (OLED) (6);

Cover Glass or Cover Plastic (1)/Adhesive Layer (2b)/Sensor Layer (7)/Adhesive Layer (2a)/Polarizing Film (5)/Liquid Crystal Display (LCD) or Organic EL Display (OLED) (6) ;

Cover glass or cover plastic (1)/Adhesive layer (2b)/Sensor layer (7)/Adhesive layer (2c)/Sensor layer (7)/Adhesive layer (2a)/Polarizing film (5)/Liquid crystal display device (LCD) ) or an organic EL display (OLED) (6);

As mentioned above, the image display apparatus in which each layer was laminated|stacked in this order is mentioned. In addition to these layers, a retardation film may be appropriately added, and specifically, the polarizing film 5 and the liquid crystal display (LCD) or organic EL display (OLED) 6 may be laminated with an adhesive layer interposed therebetween. can Moreover, lamination|stacking of each layer WHEREIN: An adhesive layer and/or an adhesive bond layer can be used suitably. In addition, although the polarizing film 5 of FIGS. A single-sided protective polarizing film may be used.

The pressure-sensitive adhesive layer made of the ultraviolet curable acrylic pressure-sensitive adhesive composition of the present invention is a cover glass or cover plastic 1 in an image display device, and a liquid crystal display device (LCD) or an organic EL display device (OLED) 6 on the viewing side It is an adhesive layer located between the polarizing films 5 which exist in, and although any place of the adhesive layers 2a-2c in FIGS. 1-3 may be sufficient, the adhesive layer in contact with the polarizing film 5 (2a in a figure) It is more preferable from a viewpoint of ultraviolet-absorbing ability to use the adhesive layer of this invention for this. By disposing the pressure-sensitive adhesive layer made of the ultraviolet curable acrylic pressure-sensitive adhesive composition of the present invention at the above position, the polarizing film and the like in the image display device can be protected from the ultraviolet light incident from the viewer side in the image display device, which is preferable.

The UV-curable acrylic pressure-sensitive adhesive composition of the present invention includes a monomer component containing an alkyl (meth)acrylate and/or a partial polymer of the monomer component, a UV absorber, and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more. will do

As said alkyl (meth)acrylate, what has a linear or branched C1-C24 alkyl group at the ester terminal can be illustrated. Alkyl (meth)acrylate can be used individually by 1 type or in combination of 2 or more type. In addition, alkyl (meth) acrylate refers to an alkyl acrylate and/or an alkyl methacrylate, and has the same meaning as (meth) in the present invention.

As said alkyl (meth)acrylate, the alkyl (meth)acrylate which has an alkyl group which has a C4-C9 branch at the ester terminal can be illustrated, for example. The said alkyl (meth)acrylate is preferable at the point which is easy to balance an adhesive characteristic. Specifically, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl ( Meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, etc. are mentioned. and these can be used individually by 1 type or in combination of 2 or more types.

In the present invention, the alkyl (meth) acrylate having an alkyl group having 1 to 24 carbon atoms at the ester terminal is preferably 40% by weight or more based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer, 50 Weight % or more is more preferable, and 60 weight% or more is still more preferable.

As a monomer component which forms the said (meth)acrylic-type polymer, it can contain copolymerization monomers other than the said alkyl (meth)acrylate as a monofunctional monomer component. A copolymerization monomer can be used as the remainder of the said alkyl (meth)acrylate in a monomer component.

As a copolymerization monomer, a cyclic nitrogen-containing monomer can be contained, for example. As the cyclic nitrogen-containing monomer, those having a polymerizable functional group having an unsaturated double bond, such as a (meth)acryloyl group or a vinyl group, and having a cyclic nitrogen structure can be used without particular limitation. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure. Examples of the cyclic nitrogen-containing monomer include N-vinylpyrrolidone; lactam-based vinyl monomers such as N-vinyl-ε-caprolactam and methylvinylpyrrolidone; and vinyl monomers having a nitrogen-containing heterocycle such as vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, and vinyl morpholine. . Moreover, the (meth)acryl monomer containing heterocyclic rings, such as a morpholine ring, a piperidine ring, a pyrrolidine ring, and a piperazine ring, is mentioned. Specific examples thereof include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Among the cyclic nitrogen-containing monomers, a lactam-based vinyl monomer is preferable.

In the present invention, the cyclic nitrogen-containing monomer is preferably 0.5 to 50% by weight, more preferably 0.5 to 40% by weight, and 0.5 to 30% by weight based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer. % by weight is more preferred.

The monomer component used in the present invention may include a hydroxyl group-containing monomer as a monofunctional monomer component. As the hydroxyl group-containing monomer, those having a polymerizable functional group having an unsaturated double bond, such as a (meth)acryloyl group or a vinyl group, and having a hydroxyl group can be used without particular limitation. As the hydroxyl group-containing monomer, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate ) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12- hydroxyalkyl (meth)acrylates such as hydroxylauryl (meth)acrylate; Hydroxyalkylcycloalkane (meth)acrylates, such as (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, are mentioned. In addition, hydroxyethyl (meth)acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. are mentioned. These may be used alone or in combination. Among these, hydroxyalkyl (meth)acrylate is suitable.

In the present invention, the hydroxyl group-containing monomer is preferably 1% by weight or more, and more preferably 2% by weight or more from the viewpoint of increasing adhesion and cohesion with respect to the total amount of the monofunctional monomer component forming the (meth)acrylic polymer. Preferably, it is more preferable that it is 3 weight% or more. On the other hand, when the amount of the hydroxyl group-containing monomer is too large, the pressure-sensitive adhesive layer may become hard and the adhesive force may decrease, and the viscosity of the pressure-sensitive adhesive may become excessively high or gelled. It is preferable that it is 30 weight% or less with respect to the whole amount of the monofunctional monomer component which forms a (meth)acrylic-type polymer, 27 weight% or less is more preferable, and 25 weight% or less is still more preferable.

Moreover, as a monomer component which forms the said (meth)acrylic-type polymer, it can contain other functional group containing monomers as a monofunctional monomer, For example, a carboxyl group containing monomer and the monomer which has a cyclic ether group are mentioned.

As a carboxyl group-containing monomer, what has a polymerizable functional group which has an unsaturated double bond, such as a (meth)acryloyl group or a vinyl group, and has a carboxyl group can be used without restriction|limiting in particular. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like. It can be used alone or in combination. Itaconic acid and maleic acid can use these anhydrides. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is especially preferable. In addition, as the monomer component used in the production of the (meth)acrylic polymer, a carboxyl group-containing monomer may be arbitrarily used, and on the other hand, it is not necessary to use a carboxyl group-containing monomer.

As the monomer having a cyclic ether group, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group and having a cyclic ether group such as an epoxy group or an oxetane group can be used without any particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether. . Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate, 3-butyl-oxetanylmethyl (meth)acrylate, 3-hexyl-oxetanylmethyl (meth)acrylate, etc. are mentioned. These may be used alone or in combination.

In the present invention, the carboxyl group-containing monomer and the monomer having a cyclic ether group are preferably 30% by weight or less, more preferably 27% by weight or less, based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer, 25% by weight or less is more preferable.

As a monomer component forming the (meth)acrylic polymer, as a copolymerized monomer, for example, CH ₂ =C(R ¹ )COOR ² (R ¹ is hydrogen or a methyl group, R ² is a substituted substituted group having 1 to 3 carbon atoms) and alkyl (meth)acrylates represented by an alkyl group or a cyclic cycloalkyl group.

Here, ^{the substituent of the substituted alkyl group having 1 to 3 carbon atoms as R 2} is preferably an aryl group having 3 to 8 carbon atoms or an aryloxy group having 3 to 8 carbon atoms. Although it does not limit as an aryl group, A phenyl group is preferable.

Examples of such a monomer represented by CH ₂ =C(R ¹ )COOR ² include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, 3,3,5-trimethylcyclo Hexyl (meth)acrylate, isobornyl (meth)acrylate, etc. are mentioned. These may be used alone or in combination.

In the present invention, the _{(meth)acrylate represented by CH 2} =C(R ¹ )COOR ² may be used in an amount of 50% by weight or less based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer, and , 45 weight% or less is preferable, 40 weight% or less is more preferable, and 35 weight% or less is still more preferable.

Examples of other copolymer monomers include vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; glycol-based acrylic ester monomers such as (meth)acrylic acid polyethylene glycol, (meth)acrylic acid polypropylene glycol, (meth)acrylic acid methoxyethylene glycol, and (meth)acrylic acid methoxypolypropylene glycol; acrylic acid ester-based monomers such as (meth)acrylic acid tetrahydrofurfuryl, fluorine (meth)acrylate, silicone (meth)acrylate and 2-methoxyethyl acrylate; An amide group-containing monomer, an amino group-containing monomer, an imide group-containing monomer, N-acryloylmorpholine, a vinyl ether monomer and the like can also be used. Moreover, as a copolymerization monomer, the monomer which has a cyclic structure, such as terpene (meth)acrylate and dicyclopentanyl (meth)acrylate, can be used.

Moreover, the silane-type monomer etc. containing a silicon atom are mentioned. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8- Vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltri Ethoxysilane, 10-acryloyloxydecyl triethoxysilane, etc. are mentioned.

As a monomer component forming the (meth)acrylic polymer, in addition to the monofunctional monomers exemplified above, a polyfunctional monomer may be contained as needed to adjust the cohesive force of the pressure-sensitive adhesive.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, for example, (poly)ethylene glycol di(meth)acrylate, (poly) Propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetra Ester compounds of polyhydric alcohols and (meth)acrylic acid, such as methylol methane tri(meth)acrylate; Allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di (meth) acrylate, hexyl di (meth) acrylate, etc. are mentioned. have. Among these, trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be used suitably. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more type.

Although the amount of the polyfunctional monomer used varies depending on the molecular weight or the number of functional groups, it is preferably used in an amount of 3 parts by weight or less, more preferably 2 parts by weight or less, and 1 part by weight or less with respect to 100 parts by weight of the total of the monofunctional monomers. is more preferable. Moreover, although it does not specifically limit as a lower limit, It is preferable that it is 0 weight part or more, and it is more preferable that it is 0.001 weight part or more. Adhesion can be improved by the usage-amount of a polyfunctional monomer within the said range.

In the present invention, a partial polymer of the monomer component may be used. The "partially polymerized product" as used herein is obtained by partially polymerizing a monomer component. The polymerization rate of the partial polymer of the monomer component is as described later.

The ultraviolet curable acrylic pressure-sensitive adhesive composition of the present invention contains an ultraviolet absorber.

Although it does not specifically limit as a ultraviolet absorber, For example, a triazine type ultraviolet absorber, a benzotriazole type ultraviolet absorber, a benzophenone type ultraviolet absorber, an oxybenzophenone type ultraviolet absorber, a salicylate type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, etc. These can be used individually by 1 type or in combination of 2 or more type. Among these, triazine-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers are preferable, triazine-based ultraviolet absorbers having two or less hydroxyl groups in one molecule, and benzotriazole-based ultraviolet absorbers having one benzotriazole skeleton in one molecule. It is especially preferable that it is at least 1 sort(s) of ultraviolet absorber selected from the group which consists of it has favorable solubility with respect to the monomer used for formation of an ultraviolet curable acrylic adhesive composition, and also has high ultraviolet-absorbing ability in wavelength 380nm vicinity.

Specific examples of the triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule include 2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]-6- (4-methoxyphenyl)-1,3,5-triazine (Tinosorb S, manufactured by BASF), 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibu Toxyphenyl)-1,3,5-triazine (TINUVIN 460, manufactured by BASF), 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl) Reaction product of 5-hydroxyphenyl with [(C10-C16 (mainly C12-C13)alkyloxy)methyl]oxirane (TINUVIN 400 from BASF), 2-[4,6-bis(2,4-dimethyl Phenyl)-1,3,5-triazin-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol, 2-(2,4-dihydroxyphenyl)- Reaction product of 4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester (TINUVIN 405, manufactured by BASF), 2-(4, 6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (TINUVIN 1577, manufactured by BASF), 2-(4,6-diphenyl-1,3 ,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (ADK STAB LA46, manufactured by ADEKA), 2-(2-hydroxy-4-[1) -Octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (TINUVIN 479, manufactured by BASF), etc. can be used.

Moreover, as a benzotriazole type ultraviolet absorber which has one benzotriazole skeleton in 1 molecule, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1, 1,3,3-tetramethylbutyl)phenol (TINUVIN 928, manufactured by BASF), 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzenepropane Ester compound of acid and 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy (C7-9 branched and straight chain alkyl) (TINUVIN 384-2, BASF Manufactured), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN 900, manufactured by BASF), 2-(2H-benzotriazole- 2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (TINUVIN 928, manufactured by BASF), methyl-3-(3-( 2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate/reaction product of polyethylene glycol 300 (TINUVIN 1130, manufactured by BASF), 2-(2H-benzotriazole- 2-yl)-p-cresol (TINUVIN P, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN 234, BASF), 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (TINUVIN 326, manufactured by BASF), 2-(2H-benzotria Zol-2-yl)-4,6-di-tert-pentylphenol (TINUVIN 328, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3- Tetramethylbutyl)phenol (TINUVIN 329, manufactured by BASF), methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and polyethylene glycol 300 (TINUVIN 213, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (TINUVIN 571, manufactured by BASF), 2-[2-hydroxy- 3-(3,4,5,6-tetrahydrophthalimidemethyl)-5-methylphene Neil] benzotriazole (Sumisorb 250, manufactured by Sumitomo Chemical Co., Ltd.) or the like can be used.

Moreover, as said benzophenone-type ultraviolet absorber (benzophenone-type compound) and an oxybenzophenone-type ultraviolet absorber (oxybenzophenone-type compound), 2, 4- dihydroxybenzophenone, 2-hydroxy-4-methyl Toxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone , 4-benzyloxy-2-hydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4-dimethoxybenzophenone, etc. are mentioned. have.

Moreover, as said salicylic acid ester type|system|group ultraviolet absorber (salicylic acid ester type compound), For example, phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, phenyl-2-acrylo Iloxy-4-methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl -2-hydroxy-3-methylbenzoate, phenyl-2-hydroxy-4methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl2-hydroxy-3-methoxybenzoate, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (TINUVIN 120, manufactured by BASF); and the like.

Examples of the cyanoacrylate-based ultraviolet absorber (cyanoacrylate-based compound) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, Alkenyl-2-cyanoacrylate, alkynyl-2-cyanoacrylate, etc. are mentioned.

The ultraviolet absorber may be used alone or in mixture of two or more, but the content as a whole is about 0.1 to 5 parts by weight based on 100 parts by weight of the monofunctional monomer component forming the (meth)acrylic polymer. It is preferable, and it is more preferable that it is about 0.5-3 weight part. By making the addition amount of a ultraviolet absorber into the said range, since the ultraviolet-ray absorption function of an adhesive layer can fully be exhibited and it does not become interference with ultraviolet polymerization, it is preferable.

The ultraviolet curable acrylic adhesive composition of this invention contains the photoinitiator (A) which has an absorption band at wavelength 400nm or more. The photoinitiator (A) having an absorption band at a wavelength of 400 nm or more may have an absorption band at a wavelength of 400 nm or more, and may have an absorption band at a wavelength of less than 400 nm. When an ultraviolet absorber was included in an adhesive composition, when ultraviolet-ray polymerization was performed, the ultraviolet-ray was absorbed by the said ultraviolet absorber, and it was a thing which did not fully superpose|polymerize. However, since the adhesive composition of this invention has the photoinitiator (A) which has an absorption band at a wavelength of 400 nm or more, in spite of containing a ultraviolet absorber, it can fully superpose|polymerize.

As the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819, manufactured by BASF), 2,4,6-trimethylbenzoyl-diphenyl- and phosphine oxide (LUCIRIN TPO, manufactured by BASF).

The photoinitiator (A) which has an absorption band at the said wavelength of 400 nm or more may be used independently, and may mix and use 2 or more types.

In addition, the addition amount of the photoinitiator (A) having an absorption band at the wavelength of 400 nm or more is not particularly limited, but it is preferably less than the amount of the ultraviolet absorber added, and 100 parts by weight of a monofunctional monomer component forming a (meth)acrylic polymer It is preferable that it is about 0.005-1 weight part with respect to it, and it is more preferable that it is about 0.02-0.5 weight part. When the addition amount of a photoinitiator (A) is the said range, since ultraviolet-ray polymerization can fully advance, it is preferable.

Moreover, the ultraviolet curable acrylic adhesive composition of this invention can contain the photoinitiator (B) which has an absorption band at wavelength less than 400 nm. Moreover, it is preferable that a photoinitiator (B) does not have an absorption band at a wavelength of 400 nm or more. The photopolymerization initiator (B) is not particularly limited as long as it generates radicals by ultraviolet rays to initiate photopolymerization, and has an absorption band at a wavelength of less than 400 nm, and all commonly used photoinitiators can be suitably used. For example, benzoin ether-based photopolymerization initiator, acetophenone-based photopolymerization initiator, α-ketol-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, benzyl-based photopolymerization initiator, benzophenone-based photopolymerization initiator, ketal-based photopolymerization initiator , a thioxanthone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like can be used.

Specifically, as a benzoin ether type photoinitiator, For example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1 and 2-diphenylethan-1-one, anisolemethyl ether, and the like.

Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, 4 -t-butyldichloroacetophenone etc. are mentioned.

As the α-ketol-based photopolymerization initiator, for example, 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-hydroxy-2-methylpropane-1- On and so on.

Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

As a benzoin type photoinitiator, benzoin etc. are mentioned, for example.

As a benzyl type photoinitiator, benzyl etc. are contained, for example.

Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenylketone.

The ketal-based photopolymerization initiator includes benzyldimethyl ketal and the like.

To a thioxanthone type photoinitiator, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothi oxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like.

The photoinitiator (B) having an absorption band at a wavelength of less than 400 nm can be used alone or in combination of two or more. The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be added within a range that does not impair the effects of the present invention, but as an amount to be added, 100 parts by weight of a monofunctional monomer component forming a (meth)acrylic polymer It is preferable that it is about 0.005-0.5 weight part with respect to it, and it is more preferable that it is about 0.02-0.1 weight part.

In the present invention, a partial polymerization product (prepolymer composition) of a monomer component that is partially polymerized by adding a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm to the monomer component and irradiating an ultraviolet ray to the monomer component (prepolymer composition) with a wavelength of 400 nm or more It is preferable to add the photopolymerization initiator (A) and the ultraviolet absorber which have an absorption band to it, and to carry out ultraviolet polymerization. When adding the photopolymerization initiator (A) having an absorption band at the wavelength of 400 nm or more to the partial polymerization product (prepolymer composition) of the monomer component partially polymerized by irradiation with ultraviolet light, it is preferable to add the photopolymerization initiator after dissolving the photoinitiator in the monomer. do.

In addition, the ultraviolet curable acrylic pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent. It is preferable that the compounding quantity of a silane coupling agent is 1 weight part or less with respect to 100 weight part of monofunctional monomer components which form a (meth)acrylic-type polymer, 0.01-1 weight part is more preferable, 0.02-0.6 weight part is still more preferable.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4epoxycyclo). Epoxy group-containing silane coupling agent such as hexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-n -(1,3-dimethylbutylidene)propylamine, amino group-containing silane coupling agent such as N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyl (meth)acryl group containing silane coupling agents, such as triethoxysilane, isocyanate group containing silane coupling agents, such as 3-isocyanate propyl triethoxysilane, etc. are mentioned.

The ultraviolet curable acrylic pressure-sensitive adhesive composition of the present invention may contain a crosslinking agent. Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, silicone crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, silane crosslinking agents, alkyletherified melamine crosslinking agents, metal chelate crosslinking agents, crosslinking agents such as peroxides. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types. Among these, an isocyanate type crosslinking agent is used preferably.

The crosslinking agent may be used alone or in combination of two or more, but the content as a whole is 5 parts by weight or less with respect to 100 parts by weight of the monofunctional monomer component forming the (meth)acrylic polymer. It is preferable, It is more preferable that it is 0.01-5 weight part, 0.01-4 weight part is still more preferable, 0.02-3 weight part is especially preferable.

The isocyanate-based crosslinking agent refers to a compound having two or more isocyanate groups in one molecule (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or quantification, etc.). Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, for example, lower aliphatic polyisocyanates, such as butylene diisocyanate and hexamethylene diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, alicyclic isocyanates, such as isophorone diisocyanate, 2,4- Aromatic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate, trimethylolpropane/tolylene diisocyanate trimer adduct (trade name: Coronate L, Nippon Polyurethane Kogyo Co., Ltd. product), trimethylolpropane/hexamethylene diisocyanate trimer adduct (trade name: Coronate HL, Nippon Polyurethane Kogyo Co., Ltd. product), isocyanurate form of hexamethylene diisocyanate ( Brand name: isocyanate adducts such as Coronate HX, manufactured by Nippon Polyurethane Kogyo Co., Ltd., trimethylolpropane adduct of xylylene diisocyanate (trade name: D110N, manufactured by Mitsui Chemicals Co., Ltd.), hexamethylene diisocyanate trimethylolpropane adduct (trade name: D160N, manufactured by Mitsui Chemicals Co., Ltd.); Polyether polyisocyanate, polyester polyisocyanate, and the polyisocyanate polyisocyanate etc. which were polyfunctionalized by the addition product of these and various polyols, an isocyanurate bond, a biuret bond, an allophanate bond, etc. are mentioned.

The ultraviolet curable acrylic adhesive composition of this invention may contain the additive suitable according to a use other than the said component. For example, a tackifier (For example, a solid, semi-solid, or liquid thing at normal temperature which consists of a rosin derivative resin, a polyterpene resin, a petroleum resin, oil-soluble phenol resin, etc.); fillers such as hollow glass balloons; plasticizer; anti-aging; antioxidant etc. are mentioned.

In this invention, it is preferable to adjust the said ultraviolet curable acrylic adhesive composition to the viscosity suitable for the operation|work which performs application|coating etc. on a base material. Adjustment of the viscosity of an ultraviolet curable acrylic adhesive composition is performed, for example by adding various polymers, such as a thickening additive, a polyfunctional monomer, etc., or partial polymerization of the monomer component in an ultraviolet curable acrylic adhesive composition. In addition, the said partial polymerization may be performed before adding various polymers, such as a thickening additive, a polyfunctional monomer, etc., and may be performed after it. Since the viscosity of the UV-curable acrylic pressure-sensitive adhesive composition changes depending on the amount of additives, the polymerization rate in the case of partial polymerization of the monomer component in the UV-curable acrylic pressure-sensitive adhesive composition cannot be uniquely determined, but the target is about 20% or less. It is preferable, about 3 to 20 % is more preferable, and about 5 to 15 % is still more preferable. When it exceeds 20%, since the viscosity becomes too high, it becomes difficult to apply|coat to a base material.

Although the transmission b* value of the adhesive layer formed by the ultraviolet curable acrylic adhesive composition of this invention is not specifically limited, It is preferable that it is 3.0 or less, It is more preferable that it is 1.5 or less, It is still more preferable that it is 0.5 or less. The said b* value points out the b* value (chromaticity) in the L*a*b* color system based on JIS Z8729, For example, a spectrophotometer (Product name: U4100, Hitachi High-Technologies Co., Ltd. product) can be used to measure

The transmittance|permeability in wavelength 380nm of the adhesive layer formed of the ultraviolet curable acrylic adhesive composition of this invention is 40 % or less, It is preferable that it is 20 % or less, It is more preferable that it is 8 % or less. When the transmittance|permeability wavelength in wavelength 380nm is the said range, since an incident ultraviolet-ray can fully be interrupted|blocked, deterioration of optical members including a liquid crystal panel, an organic electroluminescent element, a polarizer, etc. can be suppressed.

Moreover, the transmittance|permeability in wavelength 400nm of the adhesive layer formed with the ultraviolet curable acrylic adhesive composition of this invention is 30 % or more, It is preferable that it is 50 % or more, It is more preferable that it is 70 % or more. When the transmittance|permeability wavelength in wavelength 400nm is the said range, since the visible light which injects can fully permeate|transmit and can ensure sufficient visibility in an image display apparatus, it is preferable.

2. UV-curable acrylic adhesive layer

The ultraviolet curable acrylic adhesive layer of this invention is an adhesive layer located between the cover glass or cover plastic in an image display apparatus, and a polarizing film,

It is characterized in that it is formed by irradiating ultraviolet rays to the ultraviolet curable acrylic pressure-sensitive adhesive composition to photopolymerize the monomer component in the ultraviolet curable acrylic pressure-sensitive adhesive composition.

For the ultraviolet curable acrylic pressure-sensitive adhesive composition, those described above can be used.

The illuminance of the ultraviolet ray irradiated to the ultraviolet curable acrylic pressure-sensitive adhesive composition is preferably 5 mW/cm 2 or more. When the illuminance of the ultraviolet ray is less than 5 mW/cm 2 , the polymerization reaction time becomes long and productivity may be poor. Moreover, as for the illuminance of the said ultraviolet-ray, 200 mW/cm<2> or less is preferable. When the illuminance of the ultraviolet light exceeds 200 mW/cm 2 , the photopolymerization initiator is rapidly consumed, so that the polymer has a low molecular weight, and in particular, the holding power at high temperature may be lowered. Moreover, it is preferable that the accumulated light amount of ultraviolet-ray is 100 mJ/cm<2> - 5000 mJ/cm<2>.

Although the ultraviolet lamp used for this invention is not specifically limited, An LED lamp is preferable. Since an LED lamp is a lamp with a low emission heat compared with other ultraviolet lamps, the temperature during superposition|polymerization of an adhesive layer can be suppressed. Therefore, while reduction in molecular weight of a polymer can be prevented and the fall of the cohesive force of an adhesive layer is prevented, the holding force in high temperature at the time of setting it as an adhesive sheet can be raised. It is also possible to combine a plurality of ultraviolet lamps. In addition, by intermittently irradiating ultraviolet rays, it is also possible to provide a bright stage for irradiating ultraviolet rays and a dark stage for not irradiating ultraviolet rays.

In the present invention, the final polymerization rate of the monomer component in the ultraviolet curable acrylic pressure-sensitive adhesive composition is preferably 90% or more, more preferably 95% or more, and still more preferably 98% or more.

In the present invention, the peak wavelength of ultraviolet rays irradiated to the ultraviolet curable acrylic pressure-sensitive adhesive composition is preferably in the range of 200 to 500 nm, more preferably in the range of 300 to 450 nm. When the peak wavelength of an ultraviolet-ray exceeds 500 nm, a photoinitiator may not decompose|disassemble and a polymerization reaction may not start. Moreover, when the peak wavelength of an ultraviolet-ray is less than 200 nm, a polymer chain may be cut|disconnected and adhesive property may fall.

It is preferable that it is 50 micrometers or more from a viewpoint of ensuring the ultraviolet-ray absorption function, as for the thickness of the adhesive layer of this invention, it is more preferable that it is 100 micrometers or more, It is still more preferable that it is 150 micrometers or more. Although the upper limit of the thickness of an adhesive layer is not specifically limited, It is preferable that it is 10 mm or less. When the thickness of an adhesive layer exceeds 10 mm, since permeation|transmission of an ultraviolet-ray becomes difficult and superposition|polymerization of a monomer component takes time and productivity may fall, it is unpreferable.

Although the gel fraction of the adhesive layer of this invention is not specifically limited, It is preferable that it is 50 % or more, It is more preferable that it is 75 % or more, It is still more preferable that it is 85 % or more. When the gel fraction of an adhesive layer is small, cohesive force may fall, and when too large, adhesive force may fall.

It is as above-mentioned about the transmittance|permeability b* value of the said adhesive layer, the transmittance|permeability in wavelength 380nm, and the transmittance|permeability in wavelength 400nm.

The adhesive layer of this invention is used for an image display apparatus, More specifically, it is located between the cover glass or cover plastics in an image display apparatus, and a polarizing film. When the adhesive layer of this invention exists in the said position, a ultraviolet-ray absorption function can fully be exhibited.

3. Polarizing film with pressure-sensitive adhesive layer

The polarizing film which has an adhesive layer of this invention has a polarizing film and the said ultraviolet curable acrylic adhesive layer in at least one surface of the said polarizing film, It is characterized by the above-mentioned.

Although the method for forming the UV-curable acrylic pressure-sensitive adhesive layer is as described above, the pressure-sensitive adhesive layer may be formed by applying the UV-curable acrylic pressure-sensitive adhesive composition directly on the polarizing film, or after forming the pressure-sensitive adhesive layer on a release film or the like, the polarizing film You may form an adhesive layer on a polarizing film by transcribe|transferring an adhesive layer.

As said polarizing film, it is preferable that it is a polarizing film which has a transparent protective film on at least single side|surface of a 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 uniaxial and polyene-based oriented films such as those stretched, dehydrated products of polyvinyl alcohol, and dehydrochlorinated products of polyvinyl chloride. Among these, a polarizer made of 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 about 5-80 micrometers.

A polarizer in which a polyvinyl alcohol-based film is dyed with iodine and uniaxially stretched can be produced by, for example, immersing polyvinyl alcohol in an aqueous solution of iodine, dyeing the polyvinyl alcohol-based film, and stretching to 3 to 7 times the 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. By washing the polyvinyl alcohol-based film with water, contamination and blocking agents on the surface of the polyvinyl alcohol-based film can be washed, and by swelling the polyvinyl alcohol-based film, there is also an effect of preventing unevenness such as staining of dyeing. Extending 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.

Moreover, in this invention, the thin-shaped polarizer whose thickness is 10 micrometers or less can also be used. It is preferable that the said thickness is 1-7 micrometers from a viewpoint of thinning. Such a thin polarizer has little thickness nonuniformity, is excellent in visibility, and since there are few dimensional changes, it is excellent in durability, Furthermore, the point which can attain thickness reduction as a polarizing film is preferable.

As a thin polarizer, typically, Unexamined-Japanese-Patent No. 51-069644, Unexamined-Japanese-Patent No. 2000-338329, International Publication No. 2010/100917 pamphlet, International Publication No. 2010/100917 pamphlet, or Japanese Patent Publication The thin-shaped polarizing film described in the specification of 4751481 and Unexamined-Japanese-Patent No. 2012-073563 is mentioned. These thin polarizing films can be obtained by a manufacturing method including the process of extending|stretching a polyvinyl alcohol-type resin (henceforth PVA-type resin) layer and the resin base material for extending|stretching in the state of a laminated body, and the process of dyeing. According to this manufacturing method, even if the PVA-based resin layer is thin, by being supported by the resin substrate for stretching, stretching can be performed without defects such as breakage due to stretching.

As said thin polarizing film, among the manufacturing methods including the process of extending|stretching and dyeing in the state of a laminated body, from the point which can extend|stretch at high magnification and can improve polarization performance, International Publication No. 2010/100917 pamphlet, international It is preferable to obtain by a manufacturing method including the process of extending|stretching in a boric acid aqueous solution which has description in Unexamined-Japanese-Patent No. 2010/100917 pamphlet, or the specification of Japanese Patent No. 4751481 or Unexamined-Japanese-Patent No. 2012-073563, Especially the thing obtained by the Japanese Patent Publication It is preferable to obtain by the manufacturing method including the process of carrying out auxiliary|air_stretching auxiliary before extending|stretching in boric-acid aqueous solution which has description in the specification of 4751481 or Unexamined-Japanese-Patent No. 2012-073563.

As a material for forming the transparent protective film provided on one or both surfaces of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene or acrylonitrile styrene copolymer ( AS resin), etc. styrene-type polymers, polycarbonate-type polymers, etc. are mentioned. In addition, polyethylene, polypropylene, polyolefin having a cyclo or norbornene structure, polyolefin polymer such as ethylene/propylene copolymer, vinyl chloride polymer, amide polymer such as nylon or aromatic polyamide, imide polymer, sulfone polymer Polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy Polymers or blends of the above polymers are also exemplified as examples of the polymer forming the transparent protective film. The transparent protective film can also be formed as a cured resin layer of a thermosetting type such as an acrylic type, a urethane type, an acrylic urethane type, an epoxy type, or a silicone type, or an ultraviolet curing type.

Although the thickness of a protective film can be determined suitably, it is generally about 1-500 micrometers from viewpoints, such as workability|operativity, such as intensity|strength and handleability, and thin film property.

The polarizer and the protective film are usually in close contact with each other through a water-based adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex-based adhesive, a water-based polyurethane, and an aqueous polyester. In addition to the above, examples of the adhesive for the polarizer and the transparent protective film include an ultraviolet curing adhesive, an electron beam curing adhesive, and the like. The adhesive for an electron beam curing type polarizing film shows suitable adhesiveness with respect to the said various transparent protective films. Further, the adhesive used in the present invention may contain a metal compound filler.

The surface of the transparent protective film on which the polarizer is not adhered may be treated with a hard coat layer, antireflection treatment, sticking prevention, or treatment for diffusion or antiglare.

Moreover, when the adhesive layer of the polarizing film which has an adhesive layer of this invention is exposed, you may protect an adhesive layer with a peeling film (separator) until it uses practically. As a peeling film, the thing mentioned above is mentioned. When a peeling film is used as a base material in preparation of the said adhesive layer, by bonding the adhesive layer on a peeling film and a polarizing film, the said peeling film can be used as a peeling film of the adhesive layer of a polarizing film which has an adhesive layer, It is possible to simplify the process.

4. Manufacturing method of the pressure-sensitive adhesive layer

The present invention is a method for producing a pressure-sensitive adhesive layer formed from an ultraviolet curable acrylic pressure-sensitive adhesive composition containing a photopolymerization initiator (B),

A step of forming a partial polymer of the monomer component by irradiating ultraviolet rays to a composition comprising a monomer component containing an alkyl (meth) acrylate and the photopolymerization initiator (B);

A step of adding an ultraviolet absorber and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more to the partial polymer of the monomer component to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition;

A step of coating the ultraviolet curable acrylic pressure-sensitive adhesive composition on at least one side of a substrate and irradiating the ultraviolet curable acrylic pressure-sensitive adhesive composition with ultraviolet rays

It relates to a method of manufacturing an ultraviolet-curable acrylic pressure-sensitive adhesive layer comprising a.

Each component constituting the UV-curable acrylic pressure-sensitive adhesive composition is as described above.

When the pressure-sensitive adhesive layer is formed from the UV-curable acrylic pressure-sensitive adhesive composition containing the photopolymerization initiator (B), first, the monomer component containing the alkyl (meth)acrylate and the photopolymerization initiator (B) (“preaddition polymerization initiator”) In some cases, a partial polymerization product of the monomer component is formed by irradiating ultraviolet rays to a composition comprising a. The polymerization rate of the partial polymer is preferably about 20% or less, more preferably about 3 to 20%, and still more preferably about 5 to 15%. UV irradiation conditions are the same as described above.

Then, to the partial polymerization product of the monomer component, an ultraviolet absorber and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more (sometimes referred to as a “post-addition polymerization initiator”) are added, and an ultraviolet curable acrylic pressure-sensitive adhesive composition to produce About the ultraviolet absorber, the photoinitiator (A) which has an absorption band at wavelength 400nm or more, and these addition amounts are as above-mentioned.

The ultraviolet curable acrylic adhesive composition obtained in this way is coated on at least one side of a base material, and an ultraviolet curable acrylic adhesive layer can be manufactured by irradiating an ultraviolet-ray to the said ultraviolet curable acrylic adhesive composition. UV irradiation conditions are the same as described above.

It does not specifically limit as said base material, For example, various base materials, such as a peeling film and a transparent resin film base material, are mentioned, Moreover, the polarizing film mentioned later can also be used conveniently as a base material.

Examples of the constituent material of the release film include a resin film such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, a porous material such as paper, cloth, and nonwoven fabric, a net, a foam sheet, metal foil, and a laminate thereof Although suitable thin leaf bodies, such as a sieve, etc. are mentioned, A resin film is used suitably from the point excellent in surface smoothness.

Examples of the resin film include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, and a polybutylene terephthalate film. , a polyurethane film, an ethylene-vinyl acetate copolymer film, and the like.

The thickness of the release film is usually 5 to 200 µm, preferably about 5 to 100 µm. If necessary, the release film may be subjected to release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl- or fatty acid amide-based release agent, silica powder, or the like, or antistatic treatment such as coating, kneading, or vapor deposition. In particular, the peelability from the pressure-sensitive adhesive layer can be further improved by appropriately performing a release treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the release film.

Although it does not restrict|limit especially as said transparent resin film base material, Various resin films which have transparency are used. The said resin film is formed of the film of one layer. For example, as the material, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, acetate-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, and polyolefin-based resins Resin, (meth)acrylic-type resin, polyvinyl chloride-type resin, polyvinylidene chloride-type resin, polystyrene-type resin, polyvinyl alcohol-type resin, polyarylate-type resin, polyphenylene sulfide-type resin, etc. are mentioned. Among these, polyester-based resins, polyimide-based resins and polyethersulfone-based resins are particularly preferable.

It is preferable that the thickness of the said film base material is 15-200 micrometers, and it is more preferable that it is 25-188 micrometers.

A method of applying the UV-curable acrylic pressure-sensitive adhesive composition on the substrate may use an appropriate known method such as a roll coater, a bar coater, or a die coater, and is not particularly limited.

Since the reaction is inhibited by oxygen in the air, in order to block oxygen, it is preferable to form a release film or the like on the application layer of the acrylic pressure-sensitive adhesive composition or to perform photopolymerization in a nitrogen atmosphere. Moreover, the thing mentioned above is mentioned as a peeling film.

As described above, when the pressure-sensitive adhesive layer is formed from the UV-curable acrylic pressure-sensitive adhesive composition containing the photopolymerization initiator (B), the photopolymerization initiator (B) is first added to form a partial polymerization product of the monomer component, and the partial polymerization product It is preferable to post-add a ultraviolet absorber and a photoinitiator (A) having an absorption band at a wavelength of 400 nm or more to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition. By polymerization in two steps as described above, the polymerization rate of the monomer component can be increased, and the ultraviolet absorption function of the finally produced pressure-sensitive adhesive layer can be improved.

5. Image display device

The image display device of the present invention has at least a cover glass or cover plastic and a polarizing film,

It is characterized in that it has the pressure-sensitive adhesive layer between the cover glass or cover plastic and the polarizing film.

An image display apparatus has at least 1 sheet of polarizing film, and at least 1 sheet of cover glass or cover plastic, It is as above-mentioned as a specific structure. Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. luminescence) display devices and the like are preferable.

Example

Hereinafter, the present invention will be specifically described by way of Examples, but the present invention is not limited by these Examples. In addition, all parts and % in each example are based on weight. Evaluation items in Examples and the like were measured as follows.

Preparation Example 1 (Preparation of acrylic pressure-sensitive adhesive composition (a-1))

In a monomer mixture consisting of 78 parts by weight of 2-ethylhexyl acrylate (2EHA), 18 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 4 parts by weight of 2-hydroxyethyl acrylate (HEA), a photopolymerization initiator (line Addition photopolymerization initiator) 0.035 parts by weight of 1-hydroxycyclohexylphenyl ketone (trade name: Irgacure 184, manufactured by BASF), 2,2-dimethoxy-1,2-diphenylethan-1-one (trade name: After blending 0.035 parts by weight of Irgacure 651, manufactured by BASF, irradiated with ultraviolet rays until the viscosity (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30° C.) reached about 20 Pa·s, A prepolymer composition in which a part of the monomer component was polymerized (polymerization rate: 8%) was obtained. Next, 0.15 parts by weight of hexanediol diacrylate (HDDA) and 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the prepolymer composition, mixed and irradiated with ultraviolet rays, An acrylic pressure-sensitive adhesive composition (a-1) was obtained.

Preparation Example 2 (Preparation of acrylic pressure-sensitive adhesive composition (a-2))

67 parts by weight of butyl acrylate (BA), 14 parts by weight of cyclohexyl acrylate (CHA), 19 parts by weight of 4-hydroxybutyl acrylate (4HBA), 2,2-dimethoxy-1,2-di as a photopolymerization initiator 0.09 parts by weight of phenyl-1-one (trade name: Irgacure 651, manufactured by BASF Japan) and 0.09 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone (trade name: Irgacure 184, manufactured by BASF Japan) 4 A partial polymerization product (monomer syrup) having a polymerization rate of 10% was obtained by pouring into a neck flask and partially photopolymerizing by exposure to ultraviolet light in a nitrogen atmosphere. Next, 0.15 parts by weight of dipentaerythritol penta and hexaacrylate (DPHA) and 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to the partial polymer and mixed. By irradiating with an ultraviolet-ray, the acrylic adhesive composition (a-2) was obtained.

Example 1

2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]-6 in acrylic pressure-sensitive adhesive composition (a-1) dissolved in butyl acrylate to a solid content of 15% 1.4 parts of -(4-methoxyphenyl)-1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan) and bis(2,4,6-trimethylbenzoyl)-phenyl as post-addition polymerization initiator 0.2 parts of phosphine oxide (trade name: Irgacure 819, manufactured by BASF Japan) was added and stirred to obtain an ultraviolet curable acrylic pressure-sensitive adhesive composition.

The UV-curable acrylic pressure-sensitive adhesive composition was applied on the surface of the release film to a thickness of 150 μm after the pressure-sensitive adhesive layer was formed to form an application layer, and then the release film was bonded to the surface of the application layer. Then, ultraviolet irradiation was performed under the conditions of illuminance: 6.5 mW/cm<2> and light quantity: 1500 mJ/cm<2>, the said coating layer was photocured, and the adhesive sheet which has a peeling film on both surfaces of an adhesive layer was formed.

Examples 2 to 16, Comparative Examples 1 to 6

UV-curable acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the type and amount of the acrylic pressure-sensitive adhesive composition used, the UV absorber, the type and amount of the post-addition photopolymerization initiator, and the thickness after forming the pressure-sensitive adhesive layer were as described in Table 1. prepared to form an adhesive sheet. However, about Comparative Examples 5 and 6, as shown in Table 2, since the solubility of an acrylic adhesive composition and a ultraviolet absorber was bad, although the ultraviolet curable acrylic adhesive composition was prepared, formation of an adhesive sheet was not performed.

In Table 1,

a-1 is the acrylic pressure-sensitive adhesive composition (a-1) obtained in Production Example 1,

a-2 is the acrylic pressure-sensitive adhesive composition (a-2) obtained in Production Example 2,

Tinosorb S is 2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]-6-(4-methoxyphenyl)-1,3,5-triazine ( BASF Corporation),

Tinuvin 928 is 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF) )second,

LA-F70 is 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine (manufactured by ADEKA),

KEMISORB 279 is 2,2'-methylenebis[6-(benzotriazol-2-yl)-4-tert-octylphenol] (manufactured by Chemipro Gassei Co., Ltd.),

Irgacure 819: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name, manufactured by BASF Japan), having an absorption band at a wavelength of 200 to 450 nm,

Irgacure 651: 2,2-dimethoxy-1,2-diphenylethan-1-one (trade name, manufactured by BASF Japan), having an absorption band at a wavelength of 200 to 380 nm,

Irgacure 184: 1-hydroxy-cyclohexyl-phenyl-ketone (trade name, manufactured by BASF Japan), has an absorption band at a wavelength of 200 to 370 nm

indicates

The following evaluation was performed about the obtained adhesive sheet.

<solubility>

Each ultraviolet absorber used in Examples and Comparative Examples was added incidentally as shown in Table 1 with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive composition shown in Table 1, and the solubility was visually observed and evaluated according to the following evaluation criteria.

(circle): The ultraviolet absorber was melt|dissolved in the acrylic adhesive composition without a fusion|melting residue.

x: The ultraviolet absorber generated fusion|melting residual in the acrylic adhesive composition.

<Polymerization rate>

The peeling film on both sides of the adhesive sheet obtained by the Example and the comparative example was peeled, and only the adhesive layer was mounted on the weighed aluminum petri dish. The weight of the (aluminum petri dish + pressure-sensitive adhesive layer) was measured to obtain the weight of the pressure-sensitive adhesive layer before drying. After drying at 130° C. for 2 hours, after cooling for about 20 minutes at room temperature, the weight of (aluminum petri dish + adhesive) was measured again to obtain the weight of the pressure-sensitive adhesive layer after drying. The polymerization rate was calculated|required by the following formula.

<Gel fraction>

About 0.1 g of the pressure-sensitive adhesive layer was collected from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, wrapped with a porous tetrafluoroethylene sheet (trade name: NTF1122, manufactured by Nitto Denko Co., Ltd.) having an average pore diameter of 0.2 μm, and then tied with a twine. The weight at that time was measured (Zg), and the said weight was made into the weight before immersion. The weight before immersion is the total weight of the pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer collected above), the tetrafluoroethylene sheet, and the smoke thread. In addition, the total weight of the tetrafluoroethylene sheet and the smoke was also measured (Yg). Next, the pressure-sensitive adhesive layer was wrapped with a tetrafluoroethylene sheet and tied with a soft thread (referred to as a “sample”), placed in a 50 mL container filled with ethyl acetate, and left still at 23° C. for 7 days. Thereafter, a sample (after ethyl acetate treatment) is taken out from the container, transferred to an aluminum cup, dried at 130°C for 2 hours in a dryer to remove ethyl acetate, and the weight is measured (Xg) and the weight is immersed. It was set as the weight after. The gel fraction was calculated from the following formula.

Gel fraction (wt%)=(X-Y)/(Z-Y)×100

<Measurement of transmittance, b* value>

The release films on both sides of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were peeled off, and the pressure-sensitive adhesive layer was mounted on a measuring jig and measured with a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Co., Ltd.).

<Optical reliability of the pressure-sensitive adhesive layer alone>

The release films on both sides of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were peeled off, and glass (trade name: S200200, thickness: 1.3 mm, size: 45 mm × 50 mm, manufactured by Matsunami Glass Kogyo Co., Ltd.) on both sides of the pressure-sensitive adhesive layer. ), and autoclave treatment (atmospheric pressure: 0.5 MPa, temperature: 50° C.) was performed for 15 minutes. The transmittance and color after each input to the following various reliability conditions 1 to 5 were measured with U4100 (product name) manufactured by Hitachi High-Technologies Co., Ltd., and the amount of change in transmittance from the initial stage was calculated. It evaluated according to the following evaluation criteria.

(Various reliability conditions)

(Condition 1) 85℃×500h

(Condition 2) -40℃×500h

(Condition 3) 60℃, 95%×500h

(Condition 4) Heat shock (HS) (-40°C to 85°C) x 300 cycles

(Condition 5) Under UV irradiation x 100 h, illuminance: 500 W/cm 2 (300 to 700 nm), environmental temperature: 60 to 65 ° C., environmental humidity: 50%

(Evaluation standard)

(double-circle): Transmittance change amount is 0.2 % or less.

(circle): Transmittance change amount is more than 0.2% and 0.7% or less.

(triangle|delta): Transmittance change amount is more than 0.7 % and 1.0 % or less.

x: The transmittance|permeability change amount is more than 1.0 %.

<Visibility>

The polarizing film which has a TAC film (25 micrometers) to which the hard-coat process was given to one side of a 12-micrometer-thick polarizer, and has an acrylic film (20 micrometers) on the other surface of the said polarizer was prepared. Peel the release film on both sides of the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and bond the pressure-sensitive adhesive layer on each protective film of the polarizing film, and further, on the pressure-sensitive adhesive layer on both sides of the glass (trade name: S200200, thickness: 1.3) mm, size: 45 mm x 50 mm, Matsunami Glass Kogyo Co., Ltd. product) was joined, and it was set as the measurement sample. The obtained measurement sample was autoclaved (atmospheric pressure: 0.5 MPa, temperature: 50 degreeC) for 15 minutes. The color was measured by measuring with an ultraviolet visible near-infrared spectrophotometer (product name: V7100, manufactured by Nippon Bunko Co., Ltd.), and the following evaluation criteria evaluated.

○: b value of 1.4 or more and 3.4 or less

△: b value greater than 3.4 and less than or equal to 3.9

×: b value exceeds 3.9

<Durability>

The release films on both sides of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were peeled off, and glass (trade name: S200200, thickness: 1.3 mm, size: 45 mm × 50 mm, manufactured by Matsunami Glass Kogyo Co., Ltd.) on both sides of the pressure-sensitive adhesive layer. ) was joined to obtain a measurement sample. The obtained measurement sample was autoclaved (atmospheric pressure: 0.5 MPa, temperature: 50 degreeC) for 15 minutes. Various reliability conditions shown in Table 1 (Condition 1: 85 °C x 500 h, Condition 2: -40 °C x 500 h, Condition 3: 60 °C, 95% x 500 h, Condition 4: HS (-40 °C to 85 °C) x 300 Cycle, condition 5: under UV irradiation x 100 h), the evaluation sample was measured by means of a magnifying glass or an electron microscope. It evaluated by the following evaluation criteria.

(circle): There is no peeling and foaming from an edge part.

x: It peels and foaming has generate|occur|produced.

<UV resistance (protective function of polarizing film)>

A polarizing film was prepared in which one side of a polarizer having a thickness of 12 μm was protected with a TAC film (25 μm) subjected to a hard coat treatment, and the other side of the polarizer was protected with an acrylic film (20 μm). On each protective film of the polarizing film, the release films on both sides of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were peeled to bond the pressure-sensitive adhesive layers, and further, on the pressure-sensitive adhesive layers on both sides, glass (trade name: S200200, thickness: 1.3) mm, size: 45 mm x 50 mm, Matsunami Glass Kogyo Co., Ltd. product) was joined, and it was set as the measurement sample. The obtained measurement sample was autoclaved (atmospheric pressure: 0.5 MPa, temperature: 50 degreeC) for 15 minutes. After that, it was put into UV irradiation conditions of illuminance: 500 W/cm 2 (300 to 700 nm), environmental temperature: 60 to 65 ° C, and environmental humidity: 50%, and an ultraviolet visible near-infrared spectrophotometer (product name: V7100, Nippon Bunko Co., Ltd.) ), and the amount of change in transmittance from the initial stage was obtained. It evaluated according to the following evaluation criteria.

(double-circle): Transmittance change amount is 1.0 % or less.

(circle): Transmittance change amount is more than 1.0 % and 2.0 % or less.

(triangle|delta): Transmittance change amount is more than 2.0 % and 3.0 % or less.

x: The transmittance|permeability change amount is more than 3.0 %.

1: Cover glass or cover plastic
2a to 2c: pressure-sensitive adhesive layer
3a, 3b: protective film
4: Polarizer
5: Polarizing film
6: Liquid crystal display (LCD) or organic EL display (OLED)
7: sensor layer

Claims (7)

It is an ultraviolet curable acrylic adhesive composition for forming the adhesive layer located between the cover glass or cover plastic in an image display device, and a polarizing film,
The pressure-sensitive adhesive composition includes a monomer component containing an alkyl (meth) acrylate and/or a partial polymer of the monomer component, a UV absorber, a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more, and an absorption band at a wavelength of less than 400 nm A photopolymerization initiator (B) having
Based on the total amount of the monomer component, the alkyl (meth) acrylate is 40% by weight or more,
The amount of the photopolymerization initiator (A) added is smaller than the amount of the ultraviolet absorber,
The transmittance|permeability in wavelength 380nm of the adhesive layer formed from the said adhesive composition is 40 % or less, and the transmittance|permeability in wavelength 400nm is 30 % or more, The ultraviolet curable acrylic adhesive composition characterized by the above-mentioned. According to claim 1,
The permeation b* value of the pressure-sensitive adhesive layer is 3.0 or less,
It indicates the b* value (chromaticity) in the L*a*b* colorimetric system conforming to JIS Z8729, attaching the adhesive layer to a measuring jig, and using a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Co., Ltd.) It is a measured value, The ultraviolet curable acrylic adhesive composition characterized by the above-mentioned. According to claim 1,
The ultraviolet absorber is at least one ultraviolet absorber selected from the group consisting of a triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule, and a benzotriazole-based ultraviolet absorber having one benzotriazole skeleton in one molecule. UV-curable acrylic pressure-sensitive adhesive composition, characterized in that. It is an adhesive layer located between the cover glass or cover plastic in an image display apparatus, and a polarizing film,
An ultraviolet curable acrylic pressure-sensitive adhesive layer, characterized in that it is formed by irradiating an ultraviolet curable acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 3 to photopolymerizing the monomer component in the ultraviolet curable acrylic pressure-sensitive adhesive composition. Polarizing film and at least one surface of the said polarizing film have the ultraviolet curable acrylic adhesive layer of Claim 4, The polarizing film which has an adhesive layer characterized by the above-mentioned. It is a method for producing a pressure-sensitive adhesive layer formed from the UV-curable acrylic pressure-sensitive adhesive composition according to claim 1,
A step of forming a partial polymer of the monomer component by irradiating ultraviolet rays to a composition comprising a monomer component containing an alkyl (meth) acrylate and the photopolymerization initiator (B);
A step of preparing an ultraviolet curable acrylic pressure-sensitive adhesive composition by adding a UV absorber and a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more to the partial polymer of the monomer component;
A step of coating the ultraviolet curable acrylic pressure-sensitive adhesive composition on at least one side of a substrate and irradiating the ultraviolet curable acrylic pressure-sensitive adhesive composition with ultraviolet rays
A method for producing an ultraviolet curable acrylic pressure-sensitive adhesive layer, comprising: An image display device having at least a cover glass or cover plastic and a polarizing film,
Between the said cover glass or cover plastic, and a polarizing film, it has the ultraviolet curable acrylic adhesive layer of Claim 4, The image display apparatus characterized by the above-mentioned.

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