JP2022000694A - Polarizing film with adhesive layer and image display device - Google Patents

Abstract

Kind Code: A1 The present invention can solve the problem of yield reduction, and can provide a sufficient UV cut function even when a polarizing film is thin, and can suppress the occurrence of curling. An object of the present invention is to provide a polarizing film with a pressure-sensitive adhesive layer. Another object of the present invention is to provide an image display device using the pressure-sensitive adhesive layer-attached polarizing film. The present invention provides a polarizing film with an adhesive layer that is used on the viewing side of an image display device in an image display device, wherein the polarizing film with an adhesive layer is attached to both sides of the polarizing film and the polarizing film. having an agent layer, the polarizing film has a polarizer and a transparent protective film on both sides of the polarizer, and the transparent protective film on the viewing side of the polarizer has a transmittance of less than 6% at a wavelength of 380 nm, Further, the polarizing film with an adhesive layer is characterized in that the adhesive layer on the viewing side of the polarizing film has an ultraviolet absorbing function. [Selection drawing] Fig. 1

Description

The present invention relates to a polarizing film with an adhesive layer used in an image display device. The present invention also relates to an image display device using the polarizing film with an adhesive layer. Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), electronic paper, and the like.

Due to the image forming method of a liquid crystal display device, an organic EL display device, or the like, for example, in a liquid crystal display device, it is indispensable to arrange polarizing elements on both sides of the liquid crystal cell, and generally, a polarizing film is attached. Has been done. In addition to polarizing films, various optical elements have come to be used for display panels such as liquid crystal panels and organic EL panels in order to improve the display quality of displays.

The polarizing film used in these image display devices generally has a structure in which a polarizing element is sandwiched between two protective films, and triacetyl cellulose (TAC) is widely used as the protective film.

In recent years, with the trend of weight reduction and thinning of image display devices, thinning of each member used in the image display device is required, and thinning of the protective film of the polarizing film is also required. When the thickness of the protective film becomes thin, the ultraviolet rays incident on the image display device cannot be sufficiently cut, and various optical members such as liquid crystal panels and organic EL elements used in the image display device as well as the polarizing element cannot be sufficiently cut. There was a problem of accelerating the deterioration due to ultraviolet rays.

In order to solve such a problem, for example, it is a double-sided adhesive sheet arranged between the surface protection panel in the image display device and the visual recognition side of the liquid crystal module to integrate the two members. A transparent double-sided adhesive for an image display device having at least one ultraviolet absorbing layer, having a light transmittance of 30% or less at a wavelength of 380 nm, and having a visible light transmittance of 80% or more on a wavelength side longer than the wavelength of 430 nm. Sheets (see, for example, Patent Document 1) and pressure-sensitive adhesive sheets having a pressure-sensitive adhesive layer containing an acrylic polymer and a triazine-based ultraviolet absorber are known (see, for example, Patent Document 2). Further, it is known that in an adhesive type optical film provided with an adhesive layer on one side or both sides of the optical film, the adhesive layer can be imparted with an ultraviolet absorbing ability (see, for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2012-211305 Japanese Unexamined Patent Publication No. 2013-75978 Japanese Patent No. 4208187

In recent years, as described in Patent Documents 1 to 3, it has been known that various members used in an image display device are bonded together using a transparent adhesive having an ultraviolet absorbing function, but in this case, thickness unevenness occurs. There were problems in terms of occurrence, deterioration of yield, and workability.

Further, depending on the use of the polarizing film, the polarizing film may be required to have a higher ultraviolet absorbing function. Specifically, it is required that the optical characteristics do not change even when exposed to ultraviolet rays for a long time (specifically, about 300 hours) or when exposed to ultraviolet rays having a wide wavelength range. Therefore, a polarizing film satisfying such a higher ultraviolet absorption function has been desired.

Further, there is a problem that the obtained polarizing film is curled due to the thinning of the polarizing element of the polarizing film and the protective film.

Therefore, the present invention can solve the problem of low yield, can impart a higher ultraviolet ray blocking function even when the polarizing film is thin, and can suppress curl generation. It is an object of the present invention to provide a polarizing film with an adhesive layer. Another object of the present invention is to provide an image display device using the polarizing film with an adhesive layer.

As a result of diligent studies to solve the above problems, the present inventors have found the following polarizing film with an adhesive layer, and have completed the present invention.

That is, the present invention is a polarizing film with an adhesive layer used on the visual side of an image display unit in an image display device.
The polarizing film with an adhesive layer has an adhesive layer on both sides of the polarizing film and the polarizing film.
The polarizing film has a polarizing element and a transparent protective film on both sides of the polarizing element.
Polarized light with an adhesive layer, characterized in that the transmittance of the transparent protective film on the visible side of the polarizing element at a wavelength of 380 nm is less than 6%, and the adhesive layer on the visible side of the polarizing film has an ultraviolet absorbing function. Regarding film.

The transparent protective film on the visible side of the polarizing element is at least one film selected from the group consisting of a triacetyl cellulose film, an acrylic film, a polyethylene terephthalate film, and a polyolefin film having a cyclo-based or norbornene structure, and The thickness is preferably 40 μm or less.

It is preferable that the thickness of the pressure-sensitive adhesive layer on the visible side of the polarizing film is at least twice the thickness of the pressure-sensitive adhesive layer on the image display portion side of the polarizing film.

It is preferable that the adhesive layer on the visible side of the polarizing film has a transmittance of 9% or less at a wavelength of 380 nm and a transmittance of 60% or more at a wavelength of 400 nm.

The b * value of the pressure-sensitive adhesive layer on the visible side of the polarizing film is preferably 3.0 or less.

It is preferable that the adhesive layer on the visible side of the polarizing film has a transmittance of 9% or less at a wavelength of 380 nm and a transmittance of 75% or less at a wavelength of 420 nm.

It is preferable that the pressure-sensitive adhesive layer on the visible side of the polarizing film contains an acrylic polymer as a base polymer.

The polarizing film with an adhesive layer of the present invention is preferably used in a liquid crystal display device or an organic EL display device.

The present invention also relates to an image display device characterized in that the polarizing film with an adhesive layer of the present invention is used on the visual side of the image display unit.

Since the polarizing film with an adhesive layer of the present invention has a structure in which an adhesive layer having an ultraviolet absorbing function is laminated in advance on the visual side of the polarizing film, it is possible to solve the problems of process deletion and reduction in yield. Moreover, even when the polarizing film is thin, a higher ultraviolet ray blocking function can be imparted and curl generation can be suppressed. Further, since the image display device of the present invention uses the polarizing film with the pressure-sensitive adhesive layer, deterioration of various optical members such as liquid crystal panels and organic EL elements used in the image display device due to ultraviolet rays is suppressed. be able to.

It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer of this invention. It is sectional drawing which shows typically one Embodiment of the image display device of this invention. It is sectional drawing which shows typically one Embodiment of the image display device of this invention. It is sectional drawing which shows typically one Embodiment of the image display device of this invention.

1. 1. Polarizing film with adhesive layer The polarizing film with adhesive layer of the present invention is used on the visual side of the image display unit in an image display device.
The polarizing film with an adhesive layer has an adhesive layer on both sides of the polarizing film and the polarizing film.
The polarizing film has a polarizing element and a transparent protective film on both sides of the polarizing element.
The transparent protective film on the visible side of the polarizing element has a transmittance of less than 6% at a wavelength of 380 nm, and the pressure-sensitive adhesive layer on the visible side of the polarizing film has an ultraviolet absorbing function.

As shown in FIG. 1, the polarizing film 1 with an adhesive layer of the present invention has the adhesive layer 2a on the visible side / the transparent protective film 3a on the visible side / the polarizing element 4 / the transparent protective film 3b on the image display unit side / the image display unit side. The configuration may include the pressure-sensitive adhesive layer 2b, and may further include a retardation film or the like. Specifically, the visible side adhesive layer 2a / the visible side transparent protective film 3a / the polarizing element 4 / the image display unit side transparent protective film 3b / the image display unit side adhesive layer 2b / retardation film (not shown) / image It may have a structure such as an adhesive layer on the display side (not shown). The polarizing film 5 is composed of a transparent protective film 3a on the viewing side / a polarizing element 4 / a transparent protective film 3b on the image display unit side. Each layer will be described in detail below.

(1) Visible Adhesive Layer The present invention is characterized in that the adhesive layer on the visible side (adhesive layer on the visible side) of the polarizing film has an ultraviolet absorbing function. The visual-viewing adhesive layer may have an ultraviolet absorbing function, and its composition is not particularly limited.

An appropriate pressure-sensitive adhesive can be used for forming the visible-side pressure-sensitive adhesive layer, and the type thereof is not particularly limited. As the adhesive, rubber adhesive, acrylic adhesive, silicone adhesive, urethane adhesive, vinyl alkyl ether adhesive, polyvinyl alcohol adhesive, polyvinylpyrrolidone adhesive, polyacrylamide adhesive, etc. Examples include cellulose-based adhesives. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate adhesiveness, cohesiveness, and adhesiveness, and are excellent in weather resistance, heat resistance, and the like. .. The acrylic pressure-sensitive adhesive (composition) contains an acrylic polymer as a base polymer.

The acrylic pressure-sensitive adhesive composition preferably contains, for example, a partial polymer of a monomer component containing an alkyl (meth) acrylate and / or a (meth) acrylic polymer obtained from the monomer component, and an ultraviolet absorber. ..

(1-1) Partial Polymer of Monomer Component and (Meta) Acrylic Polymer The acrylic pressure-sensitive adhesive composition is obtained from the partial polymer of the monomer component containing an alkyl (meth) acrylate and / or the monomer component. Includes (meth) acrylic polymers.

Examples of the alkyl (meth) acrylate include those having a linear or branched alkyl group having 1 to 24 carbon atoms at the ester terminal. The alkyl (meth) acrylate may be used alone or in combination of two or more. The alkyl (meth) acrylate refers to an alkyl acrylate and / or an alkyl methacrylate, and has the same meaning as the (meth) of the present invention.

As the alkyl (meth) acrylate, for example, the alkyl (meth) acrylate having a branch having 1 to 9 carbon atoms can be preferably exemplified. The alkyl (meth) acrylate is preferable because it is easy to balance the adhesive properties. Specifically, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, isohexyl. Examples thereof include (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, and isononyl (meth) acrylate, and these are used alone or in combination of two or more. be able to.

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

The monomer component may contain a copolymerization monomer other than the alkyl (meth) acrylate as a monofunctional monomer component. The copolymerizable monomer can be used as the remainder of the alkyl (meth) acrylate in the monomer component.

As the copolymerization monomer, for example, a cyclic nitrogen-containing monomer can be included. 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 lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, vinylpyrazine, vinylpyrrole, and vinyl. Examples thereof include vinyl-based monomers having a nitrogen-containing heterocycle such as imidazole, vinyloxazole, and vinylmorpholin. In addition, (meth) acrylic monomers containing a heterocycle such as a morpholine ring, a piperidine ring, a pyrrolidine ring, and a piperazine ring can be mentioned. Specific examples thereof include N-acryloyl morpholine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloyl pyrrolidine and the like. Among the cyclic nitrogen-containing monomers, lactam-based vinyl monomers are preferable.

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

The monomer component used in the present invention may contain a hydroxyl group-containing monomer as a monofunctional monomer component. As the hydroxyl group-containing monomer, 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 hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as meth) acrylates, 6-hydroxyhexyl (meth) acrylates, 8-hydroxyoctyl (meth) acrylates, 10-hydroxydecyl (meth) acrylates, 12-hydroxylauryl (meth) acrylates; (4) -Hydroxyalkylcycloalkane (meth) acrylates such as hydroxymethylcyclohexyl) methyl (meth) acrylates can be mentioned. Other examples include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like. These can be used alone or in combination. Among these, hydroxyalkyl (meth) acrylate is preferable.

In the present invention, the hydroxyl group-containing monomer is preferably 1% by weight or more from the viewpoint of enhancing the adhesive force and the cohesive force with respect to the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It is more preferably 2% by weight or more, and further preferably 3% by weight or more. On the other hand, if the amount of the hydroxyl group-containing monomer is too large, the pressure-sensitive adhesive layer may become hard and the adhesive strength may be lowered, and the viscosity of the pressure-sensitive adhesive may be too high or gelled. The hydroxyl group-containing monomer is preferably 30% by weight or less, more preferably 27% by weight or less, and 25% by weight or less, based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. Is even more preferable.

Further, the monomer component forming the (meth) acrylic polymer may contain other functional group-containing monomers as the monofunctional monomer, and examples thereof include a carboxyl group-containing monomer and a monomer having a cyclic ether group. Be done.

As the carboxyl group-containing monomer, 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 carboxyl group can be used without particular limitation. 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. Can be used alone or in combination. These anhydrides can be used for itaconic acid and maleic acid. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable. A carboxyl group-containing monomer can be arbitrarily used as the monomer component used for producing the (meth) acrylic polymer of the present invention, and on the other hand, the carboxyl group-containing monomer may not be used.

Examples of the monomer having a cyclic ether group include 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 ether group such as an epoxy group or an oxetane group. It can be used without particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and the like. Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, and 3-butyl-oxetanylmethyl (meth) acrylate. , 3-Hexyl-oxetanylmethyl (meth) acrylate and the like. These can 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, preferably 27% by weight, based on the total amount of the monofunctional monomer components forming the (meth) acrylic polymer. % Or less is more preferable, and 25% by weight or less is further preferable.

The monomer component forming the (meth) acrylic polymer of the present invention may contain, for example, CH ₂ = C (R ¹ ) COOR ² (where R ¹ is a hydrogen or a methyl group and R ² is the number of carbon atoms). Examples thereof include alkyl (meth) acrylates represented by 1 to 3 substituted alkyl groups and cyclic cycloalkyl groups).

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. .. The aryl group is not limited, but 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, and 3,3,5-trimethylcyclohexyl. Examples thereof include (meth) acrylate and isobornyl (meth) acrylate. These can be used alone or in combination.

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

Other copolymerization monomers include vinyl acetate, vinyl propionate, styrene, α-methylstyrene; (meth) polyethylene glycol acrylate, (meth) polypropylene glycol (meth) acrylate, (meth) methoxyethylene glycol (meth) acrylate, (meth). Glycol-based acrylic ester monomers such as methoxypolypropylene glycol acrylate; Acrylic ester-based monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate; containing amide groups. Monomers, amino group-containing monomers, imide group-containing monomers, N-acryloylmorpholine, vinyl ether monomers and the like can also be used. Further, as the copolymerization monomer, a monomer having a cyclic structure such as terpene (meth) acrylate and dicyclopentanyl (meth) acrylate can be used.

Further, a silane-based monomer containing a silicon atom and the like can be mentioned. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-vinyloctyloxydecyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane and the like.

In addition to the above-exemplified monofunctional monomer, the monomer component forming the (meth) acrylic polymer of the present invention contains, if necessary, a polyfunctional monomer in order to adjust the cohesive force of the pressure-sensitive adhesive. be able to.

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, and is, for example, a (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 Glycoldi (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylol propanetri (meth) acrylate, tetramethylol methanetri (meth) acrylate, etc. Ester compound of polyhydric alcohol and (meth) acrylic acid; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldi (meth) acrylate, hexyldi (meth) acrylate, etc. Can be mentioned. Among these, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. The polyfunctional monomer may be used alone or in combination of two or more.

The amount of the polyfunctional monomer used varies depending on its molecular weight, the number of functional groups, and the like, but it is preferably used in an amount of 3 parts by weight or less, more preferably 2 parts by weight or less, based on 100 parts by weight of the total monofunctional monomer. More preferably, it is 1 part by weight or less. The lower limit is not particularly limited, but is preferably 0 parts by weight or more, and more preferably 0.001 part by weight or more. When the amount of the polyfunctional monomer used is within the above range, the adhesive strength can be improved.

For the production of the (meth) acrylic polymer, known production methods such as solution polymerization, radiation polymerization such as ultraviolet (UV) polymerization, bulk polymerization, and various radical polymerization such as emulsion polymerization can be appropriately selected. Further, the obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

Further, in the present invention, a partial polymer of the monomer component can also be preferably used.

When the (meth) acrylic polymer is produced by radical polymerization, the polymerization can be carried out by appropriately adding a polymerization initiator, a chain transfer agent, an emulsifier and the like used for radical polymerization to the monomer component. The polymerization initiator, chain transfer agent, emulsifier and the like used in the radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent used, and the reaction conditions, and the amount used is appropriately adjusted according to these types.

For example, in solution polymerization and the like, for example, ethyl acetate, toluene and the like are used as the polymerization solvent. As a specific example of solution polymerization, the reaction is carried out under an inert gas stream such as nitrogen, a polymerization initiator is added, and usually at about 50 to 70 ° C. under reaction conditions of about 5 to 30 hours.

Examples of the thermal polymerization initiator used for solution polymerization and the like include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 2,2'-azobis (2). -Methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovalerian acid, azobisisobutyvaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutyry) Azobisisobutyin), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.) and other azo-based initiators; persulfate. Persulfates such as potassium and ammonium persulfate, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy Neodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2 -Ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butylhydroperoxide, Examples include peroxide-based initiators such as hydrogen peroxide, combinations of persulfate and sodium hydrogen sulfite, and redox-based initiators in which peroxides and reducing agents such as combinations of peroxide and sodium ascorbate are combined. It can, but is not limited to these.

The polymerization initiator may be used alone or in combination of two or more, but is preferably about 1 part by weight or less based on 100 parts by weight of the total amount of the monomer components. , 0.005 to 1 part by weight is more preferable, and about 0.02 to 0.5 part by weight is further preferable.

When 2,2'-azobisisobutyronitrile is used as the polymerization initiator, the amount of the polymerization initiator used is about 0.2 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components. It is preferably about 0.06 to 0.2 parts by weight, and more preferably about 0.06 to 0.2 parts by weight.

Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol and the like. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.3 parts by weight with respect to 100 parts by weight of the total amount of the monomer components. It is below the degree.

Examples of the emulsifier used for emulsifying polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, ammonium polyoxyethylene alkyl ether sulfate, and sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxy. Examples thereof include nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer. These emulsifiers may be used alone or in combination of two or more.

Further, as an emulsifier into which a radically polymerizable functional group such as a propenyl group or an allyl ether group has been introduced as a reactive emulsifier, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05. , BC-10, BC-20 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Adecaria Soap SE10N (manufactured by ADEKA), and the like. The amount of the emulsifier used is preferably 5 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components.

When the (meth) acrylic polymer is produced by radiation polymerization, the monomer component can be polymerized by irradiating the monomer component with radiation such as an electron beam or ultraviolet rays (UV). Among these, ultraviolet polymerization is preferable. Hereinafter, ultraviolet polymerization, which is a preferred embodiment of radiation polymerization, will be described.

When polymerizing with ultraviolet rays, it is preferable to include a photopolymerization initiator in the monomer component because of the advantage that the polymerization time can be shortened. Therefore, when performing ultraviolet polymerization, for example, an ultraviolet curable acrylic pressure-sensitive adhesive containing a monomer component containing the alkyl (meth) acrylate and / or a partial polymer of the monomer component, an ultraviolet absorber, and a photopolymerization initiator. It is preferably formed by UV polymerization of the composition. As the pressure-sensitive adhesive layer formed by UV-polymerizing the ultraviolet-curable acrylic pressure-sensitive adhesive composition, a thick pressure-sensitive adhesive layer having a thickness of 150 μm or more can be formed, and a pressure-sensitive adhesive layer having a wide range of thickness can be formed. preferable.

The photopolymerization initiator preferably contains a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more. When the pressure-sensitive adhesive composition contains an ultraviolet absorber, when ultraviolet polymerization is carried out, the ultraviolet absorber absorbs ultraviolet rays and the polymerization cannot be sufficiently performed. However, the photopolymerization initiator (A) having an absorption band having a wavelength of 400 nm or more is preferable because it can sufficiently polymerize even though it contains an ultraviolet absorber.

Examples of the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure819, manufactured by BASF), 2,4,6-trimethylbenzoyl-. Examples thereof include diphenyl-phosphine oxide (LUCIRIN TPO, manufactured by BASF).

The photopolymerization initiator (A) having an absorption band having a wavelength of 400 nm or more may be used alone or in combination of two or more.

The amount of the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is not particularly limited, but is preferably smaller than the amount of the ultraviolet absorber described later, (meth). It is preferably about 0.005 to 1 part by weight, more preferably about 0.02 to 0.5 part by weight, based on 100 parts by weight of the monofunctional monomer component forming the acrylic polymer. When the amount of the photopolymerization initiator (A) added is within the above range, ultraviolet polymerization can be sufficiently proceeded, which is preferable.

Further, the photopolymerization initiator may contain a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm. Further, it is preferable that the photopolymerization initiator (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 a radical by ultraviolet rays to initiate photopolymerization and has an absorption band at a wavelength of less than 400 nm, and is usually used for photopolymerization. Any of the initiators can be preferably 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. A system-based photopolymerization initiator, a ketal-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like can be used.

Specifically, examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenylethane-. 1-on, anisole methyl ether and the like can be mentioned.

Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, and 4-t-butyldichloroacetophenone. And so on.

Examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-hydroxy-2-methylpropane-1-one, and the like. Can be mentioned.

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

Examples of the benzoin-based photopolymerization initiator include benzoin and the like.

Examples of the benzyl-based photopolymerization initiator include benzyl and the like.

Benzophenone-based photopolymerization initiators include, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenylketone and the like.

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

Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4. -Includes diisopropyl thioxanthone, dodecylthioxanthone, etc.

The acylphosphine oxide-based photopolymerization initiator includes, for example, 2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphin oxide and the like.

The photopolymerization initiator (B) having an absorption band having 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 having a wavelength of less than 400 nm can be added within a range that does not impair the effect of the present invention, but the addition amount is monofunctional to form a (meth) acrylic polymer. It is preferably about 0.005 to 0.5 parts by weight, and more preferably about 0.02 to 0.1 parts by weight with respect to 100 parts by weight of the sex monomer component.

In the present invention, when the monomer component is polymerized by ultraviolet rays, a photopolymerization initiator (B) having an absorption band with a wavelength of less than 400 nm is first added to the monomer component, and the monomer component is partially polymerized by irradiating with ultraviolet rays. It is preferable to add a photopolymerization initiator (A) and an ultraviolet absorber having an absorption band at a wavelength of 400 nm or more to the partial polymer (prepolymer composition) of the monomer component to carry out ultraviolet polymerization. When the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is added to the partial polymer (prepolymer composition) of the monomer component partially polymerized by irradiation with ultraviolet rays, the photopolymerization is started. It is preferable to add the agent after dissolving it in the monomer.

(1-2) Ultraviolet absorber The ultraviolet absorber contained in the acrylic pressure-sensitive adhesive composition is not particularly limited, and for example, a triazine-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and the like. Examples thereof include an oxybenzophenone-based ultraviolet absorber, a salicylate ester-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, and the like, and these can be used alone or in combination of two or more. Among these, triazine-based UV absorbers and benzotriazole-based UV absorbers are preferable, triazine-based UV absorbers having two or less hydroxyl groups in one molecule, and benzo having one benzotriazole skeleton in one molecule. At least one UV absorber selected from the group consisting of triazole UV absorbers has good solubility in the monomer used for forming the acrylic pressure-sensitive adhesive composition, and has a wavelength of around 380 nm. It is preferable because it has a high ability to absorb ultraviolet rays.

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-Methenylphenyl) -1,3,5-triazine (Tinosorb S, manufactured by BASF), 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (TINUVIN 460, manufactured by BASF), 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine-2-yl) -5-hydroxyphenyl And [(C10-C16 (mainly C12-C13) alkyloxy) methyl] reaction product with oxylan (TINUVIN400, manufactured by BASF), 2- [4,6-bis (2,4-dimethylphenyl) -1,3 , 5-Triazine-2-yl] -5- [3- (dodecyloxy) -2-hydroxypropoxy] phenol), 2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-) Reaction product of dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidate ester (TINUVIN405, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazine-2) -Il) -5-[(hexyl) oxy] -phenol (TINUVIN1577, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5- [2- (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 (TINUVIN479, manufactured by BASF) and the like can be mentioned.

Further, as a benzotriazole-based ultraviolet absorber having one benzotriazole skeleton in one molecule, 2- (2H-benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-Tetramethylbutyl) Phenzotriazole (TINUVIN 928, manufactured by BASF), 2- (2-Hydroxy-5-tert-butylphenyl) -2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzene Ester compounds of propanoic acid and 3- (2H-benzotriazole-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and linear alkyl) (TINUVIN384-2, BASF) , 2- (2H-benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (TINUVIN900, manufactured by BASF), 2- (2H-benzotriazole-2-yl) ) -6- (1-Methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN928, manufactured by BASF), Methyl-3- (3- (2H-benzotriazole) -2-yl) -5-t-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction product (TINUVIN1130, manufactured by BASF), 2- (2H-benzotriazole-2-yl) -p-cresol ( TINUVIN P, manufactured by BASF), 2 (2H-benzotriazole-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol (TINUVIN234, manufactured by BASF), 2- [5-chloro (2H) ) -Benzotriazole-2-yl] -4-methyl-6- (tert-butyl) phenol (TINUVIN326, manufactured by BASF), 2- (2H-benzotriazole-2-yl) -4,6-di-tert- Pentylphenol (TINUVIN328, manufactured by BASF), 2- (2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN329, manufactured by BASF), methyl3- (3) -(2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) reaction product of propionate and polyethylene glycol 300 (TINUVIN213, manufactured by BASF), 2- (2H-benzotriazole-2-) Il) -6-dodecyl-4-methylfe Knoll (TINUVIN571, manufactured by BASF), 2- [2-Hydroxy-3- (3,4,5,6-tetrahydrophthalimide-methyl) -5-methylphenyl] benzotriazole (Sumisorb250, manufactured by Sumitomo Chemical Co., Ltd.) And so on.

Examples of the benzophenone-based ultraviolet absorber (benzophenone-based compound) and oxybenzophenone-based ultraviolet absorber (oxybenzophenone-based compound) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy. -4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2, Examples thereof include 2', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4-dimethoxybenzophenone and the like.

Examples of the salicylic acid ester-based ultraviolet absorber (salicylic acid ester-based compound) include phenyl-2-acryloyloxybenzoate, phenyl-2-acrylyloxy-3-methylbenzoate, and phenyl-2-acryloyloxy. -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 (TINUVIN120, manufactured by BASF) and the like can be mentioned.

Examples of the cyanoacrylate-based ultraviolet absorber (cyanoacrylate-based compound) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, and alkynyl-. 2-cyanoacrylate and the like can be mentioned.

Further, as the ultraviolet absorber, for example, the product name "FDB-001" (manufactured by Yamada Chemical Co., Ltd.), the product name "SMP-122" (manufactured by Hayashihara Co., Ltd.), and the azomethine compound (trade name: BONASORB UA-). 3911, manufactured by Orient Chemical Co., Ltd.), Indore Chemicals (trade name: BONASORB UA-3701, manufactured by Orient Chemical Industry Co., Ltd.), Disperse Yellow54 (trade name: KAYASET YELLOW AG, manufactured by Nippon Kayaku Co., Ltd.) , Kinoftalone compound (trade name: MS YELLOW HD-137, manufactured by Yamada Chemical Co., Ltd.), Solvent Yellow93 (PLASTYELLOW 8000, manufactured by Arimoto Chemical Co., Ltd.), Solvent Yellow163 (KP Last Yellow MK, Kiwa Chemical Co., Ltd.) It is also possible to use a dye such as (manufactured by Co., Ltd.).

The ultraviolet absorber may be used alone or in combination of two or more, but the content as a whole is a monofunctional monomer component forming a (meth) acrylic polymer. It is preferably about 0.1 to 5 parts by weight, more preferably about 0.5 to 3 parts by weight, based on 100 parts by weight. By setting the amount of the ultraviolet absorber added within the above range, the ultraviolet absorbing function of the pressure-sensitive adhesive layer can be sufficiently exhibited, and in the case of ultraviolet polymerization, it does not interfere with the polymerization, which is preferable.

(1-3) Silane Coupling Agent Further, the acrylic pressure-sensitive adhesive composition used in the present invention may contain a silane coupling agent. The blending amount of the silane coupling agent is preferably 1 part by weight or less, more preferably 0.01 to 1 part by weight, based on 100 parts by weight of the monofunctional monomer component forming the (meth) acrylic polymer. 0.02 to 0.6 parts by weight is more preferable.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4 epoxycyclohexyl). Epyl group-containing silane coupling agent such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1, (3-Dimethylbutylidene) Amino group-containing silane coupling agents such as propylamine and N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and the like ( Meta) Examples thereof include an acrylic group-containing silane coupling agent and an isocyanate group-containing silane coupling agent such as 3-isocyanuppropyltriethoxysilane.

(1-4) Cross-linking agent The acrylic pressure-sensitive adhesive composition used in the present invention may contain a cross-linking agent. Examples of the cross-linking agent include isocyanate-based cross-linking agent, epoxy-based cross-linking agent, silicone-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent, silane-based cross-linking agent, alkyl etherified melamine-based cross-linking agent, metal chelate-based cross-linking agent, and excess. Includes cross-linking agents such as oxides. The cross-linking agent may be used alone or in combination of two or more. Among these, isocyanate-based cross-linking agents are preferably used.

The above-mentioned cross-linking agent may be used alone or in combination of two or more, but the content as a whole is a monofunctional monomer forming a (meth) acrylic polymer. It is preferably 5 parts by weight or less, more preferably 0.01 to 5 parts by weight, further preferably 0.01 to 4 parts by weight, and 0.02 to 3 parts by weight with respect to 100 parts by weight of the component. Especially preferable.

The isocyanate-based cross-linking agent refers to a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or quantification) in one molecule. Examples of the isocyanate-based cross-linking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, aliphatic 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, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylenepolyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) ), Trimethylol propane / hexamethylene diisocyanate trimeric adduct (trade name: Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), isocyanurate of hexamethylene diisocyanate (trade name: Coronate HX, Nippon Polyurethane Industry Co., Ltd.) Isocyanate adduct such as (manufactured by Mitsui Kagaku Co., Ltd.), Trimethylol propane adduct of xylylene diisocyanate (trade name: D110N, manufactured by Mitsui Kagaku Co., Ltd.), Trimethylol propane adduct of hexamethylene diisocyanate (trade name: D160N, Mitsui Kagaku Co., Ltd.) ); Polyether polyisocyanate, polyester polyisocyanate, adducts of these with various polyols, polyisocyanate polyfunctionalized by isocyanurate bond, burette bond, allophanate bond, etc. can be mentioned.

(1-5) Other Additives The acrylic pressure-sensitive adhesive composition used in the present invention may contain appropriate additives in addition to the above-mentioned components, depending on the intended use. For example, a tackifier (for example, a solid, semi-solid, or liquid material at room temperature made of a rosin derivative resin, a polyterpene resin, a petroleum resin, an oil-soluble phenol resin, etc.); a filler such as a hollow glass balloon; a plasticizer; an aging agent. Antioxidants; Antioxidants and the like can be mentioned.

(1-6) Method for Forming Visible Adhesive Layer In the present invention, the acrylic pressure-sensitive adhesive composition is preferably adjusted to have a viscosity suitable for work such as coating on a substrate. The viscosity of the acrylic pressure-sensitive adhesive composition is adjusted, for example, by adding various polymers such as a thickening additive or a polyfunctional monomer, or by partially polymerizing the monomer components in the acrylic pressure-sensitive adhesive composition. The partial polymerization may be carried out before or after the addition of various polymers such as a thickening additive or a polyfunctional monomer. Since the viscosity of the above-mentioned acrylic pressure-sensitive adhesive composition changes depending on the amount of additives and the like, the polymerization rate when the monomer component in the acrylic pressure-sensitive adhesive composition is partially polymerized cannot be uniquely determined, but as a guide. It is preferably about 20% or less, more preferably about 3 to 20%, and even more preferably about 5 to 15%. If it exceeds 20%, the viscosity becomes too high, and it becomes difficult to apply it to the substrate.

The visible side pressure-sensitive adhesive layer is formed by applying the acrylic pressure-sensitive adhesive composition to at least one surface of the base material and drying a coating film formed from the acrylic pressure-sensitive adhesive composition, or ultraviolet rays or the like. It can be formed by irradiating the active energy rays of.

The base material is not particularly limited, and for example, various base materials such as a release film and a transparent resin film base material, and a polarizing film described later can be preferably used as the base material. When the visible side pressure-sensitive adhesive layer is formed on a substrate other than the polarizing film, the visible side pressure-sensitive adhesive layer can be bonded to the polarizing film and transferred.

Examples of the constituent material of the release film include resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and non-woven fabric, nets, foam sheets, metal foils, and laminates thereof. However, a resin film is preferably used because of its excellent surface smoothness.

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

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

The transparent resin film base material is not particularly limited, but various transparent resin films are used. The resin film is formed of a single layer film. For example, the materials thereof include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and (meth) acrylic resins. , Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyallylate resin, polyphenylene sulfide resin and the like. Of these, polyester-based resins, polyimide-based resins and polyether sulfone-based resins are particularly preferable.

The thickness of the film substrate is preferably 15 to 200 μm, more preferably 25 to 188 μm.

The method of applying the acrylic pressure-sensitive adhesive composition on the substrate is roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat. , Curtain coat, lip coat, die coater and other known and appropriate methods can be used, and are not particularly limited.

When the coating film formed from the acrylic pressure-sensitive adhesive composition is dried to form the visual-viewing pressure-sensitive adhesive layer, the drying conditions (temperature, time) thereof are not particularly limited, and the pressure-sensitive adhesive composition is not particularly limited. It can be appropriately set depending on the composition, concentration and the like, and is, for example, about 60 to 170 ° C., preferably 60 to 150 ° C. for 1 to 60 minutes, preferably 2 to 30 minutes.

When the acrylic pressure-sensitive adhesive composition is an ultraviolet-curable acrylic pressure-sensitive adhesive composition and the coating film formed from the ultraviolet-curable acrylic pressure-sensitive adhesive composition is formed by irradiating the coating film with ultraviolet rays, the ultraviolet rays to be irradiated are applied. The illuminance of the above is preferably ^{5 mW / cm 2 or more.} If the illuminance of the ultraviolet rays ^{is less than 5 mW / cm 2} , the polymerization reaction time becomes long and the productivity may be inferior. The illuminance of the ultraviolet rays ^{is preferably 200 mW / cm 2} or less. When the illuminance of the ultraviolet rays ^{exceeds 200 mW / cm 2} , the photopolymerization initiator is rapidly consumed, so that the molecular weight of the polymer is lowered, and the holding power at a particularly high temperature may be lowered. Further, the integrated quantity of ultraviolet light ^is preferably ^{100mJ / cm 2 ~5000mJ / cm 2} .

The ultraviolet lamp used in the present invention is not particularly limited, but an LED lamp is preferable. Since the LED lamp is a lamp having a lower heat emission than other ultraviolet lamps, the temperature during the polymerization of the pressure-sensitive adhesive layer can be suppressed. Therefore, it is possible to prevent the polymer from having a low molecular weight, prevent a decrease in the cohesive force of the pressure-sensitive adhesive layer, and increase the holding power at a high temperature when the pressure-sensitive adhesive sheet is used. It is also possible to combine a plurality of ultraviolet lamps. Further, it is also possible to intermittently irradiate ultraviolet rays to provide a light period in which the ultraviolet rays are irradiated and a dark period in which the ultraviolet rays are not irradiated.

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, still more preferably 98% or more.

In the present invention, the peak wavelength of ultraviolet rays irradiating the ultraviolet curable acrylic pressure-sensitive adhesive composition is preferably in the range of 200 to 500 nm, and more preferably in the range of 300 to 450 nm. If the peak wavelength of ultraviolet rays exceeds 500 nm, the photopolymerization initiator may not be decomposed and the polymerization reaction may not be started. Further, if the peak wavelength of ultraviolet rays is less than 200 nm, the polymer chains may be cut and the adhesive properties may be deteriorated.

Since the reaction is inhibited by oxygen in the air, in order to block oxygen, a release film or the like is formed on a coating film formed from an ultraviolet curable acrylic pressure-sensitive adhesive composition, or a photopolymerization reaction is carried out with nitrogen. It is preferable to go in an atmosphere. Examples of the release film include the above-mentioned ones. When a release film is used, the release film can be used as it is as a separator for a polarizing film with an adhesive layer.

When the ultraviolet curable acrylic pressure-sensitive adhesive composition used in the present invention contains a photopolymerization initiator (B), a monomer component containing an alkyl (meth) acrylate and the photopolymerization initiator (B) ( A composition containing (sometimes referred to as a "pre-added polymerization initiator") is irradiated with ultraviolet rays to form a partial polymer of the monomer component, and the partial polymer of the monomer component is combined with an ultraviolet absorber and a wavelength of 400 nm. It is preferable to add the photopolymerization initiator (A) having an absorption band (sometimes referred to as “post-addition polymerization initiator”) to prepare an ultraviolet curable acrylic pressure-sensitive adhesive composition. The polymerization rate of the partial polymer is preferably about 20% or less, more preferably about 3 to 20%, still more preferably about 5 to 15%. The ultraviolet irradiation conditions are as described above.

As described above, when the pressure-sensitive adhesive layer is formed from the ultraviolet-curable acrylic pressure-sensitive adhesive composition containing the photopolymerization initiator (B), the polymerization rate of the monomer component is increased by polymerizing in the above-mentioned two steps. It can be raised, and the ultraviolet absorbing function of the finally produced pressure-sensitive adhesive layer can be improved.

The thickness of the adhesive layer on the visible side is at least twice the thickness of the adhesive layer on the image display portion side (adhesive layer on the image display portion) of the polarizing film, which will be described later, from the viewpoint of ensuring the ultraviolet absorbing function. It is preferably present, more preferably 5 times or more, and even more preferably 10 times or more. Specifically, the thickness of the visible side pressure-sensitive adhesive layer is preferably 50 μm or more, more preferably 100 μm or more, and further preferably 150 μm or more. The upper limit of the thickness of the adhesive layer on the visible side is not particularly limited, but is preferably 10 mm or less. If the thickness of the pressure-sensitive adhesive layer exceeds 10 mm, it becomes difficult for ultraviolet rays to pass through, it takes time to polymerize the monomer components, and productivity may be inferior, which is not preferable.

The gel fraction of the visible side pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 35% or more, more preferably 50% or more, and further preferably 75% or more. It is preferably 85% or more, and particularly preferably 85% or more. If the gel fraction of the adhesive layer on the visible side is small, the cohesive force may be inferior, and if it is too large, the adhesive force may be inferior.

The permeation b * value of the visible side pressure-sensitive adhesive layer is not particularly limited, but is preferably 3.0 or less, more preferably 1.5 or less, and further preferably 0.5 or less. The above b * value refers to the b * value (chromaticity) in the L * a * b * color system conforming to JIS Z8729, and is, for example, a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Corporation). ) Can be used for measurement.

The transmittance of the visible side pressure-sensitive adhesive layer at a wavelength of 380 nm is preferably 9% or less, more preferably 7% or less, further preferably 5% or less, and preferably 3% or less. Especially preferable. Since the transmittance at a wavelength of 380 nm is within the above range, the incident ultraviolet rays can be blocked to a higher degree, so that deterioration of optical members such as liquid crystal panels, organic EL elements, and polarizing elements can be remarkably suppressed. Can be done.

The transmittance of the visible side pressure-sensitive adhesive layer at a wavelength of 400 nm is preferably 60% or more, preferably 70% or more, and more preferably 75% or more. It is preferable that the transmittance at a wavelength of 400 nm is in the above range because the incident visible light can be sufficiently transmitted and sufficient visibility can be ensured in the image display device.

When the polarizing film with the pressure-sensitive adhesive layer of the present invention is used for an organic EL display device (OLED), the transmittance of the pressure-sensitive adhesive layer on the visible side at a wavelength of 420 nm is preferably 75% or less, preferably 50% or less. It is more preferably present, and further preferably 40% or less. Since the transmittance at a wavelength of 420 nm is in the above range, it is preferable from the viewpoint of protecting the light emitting element of the OLED.

When the visible side pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a release film until it is put into practical use. The release film can be used as it is as a separator for a polarizing film with an adhesive layer, and can be simplified in terms of process.

(2) Adhesive layer on the image display unit side The adhesive layer on the surface of the polarizing film on the image display unit side (adhesive layer on the image display unit side) is not particularly limited, and is detailed in the visual recognition side adhesive layer. The same acrylic pressure-sensitive adhesive composition as described above may be used, and various commonly used pressure-sensitive adhesive layers can be used.

An appropriate adhesive can be used to form the adhesive layer on the surface of the image display portion, and the type thereof is not particularly limited. As the adhesive, rubber adhesive, acrylic adhesive, silicone adhesive, urethane adhesive, vinyl alkyl ether adhesive, polyvinyl alcohol adhesive, polyvinylpyrrolidone adhesive, polyacrylamide adhesive, etc. Examples include cellulose-based adhesives. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate adhesiveness, cohesiveness, and adhesiveness, and are excellent in weather resistance, heat resistance, and the like. ..

The acrylic pressure-sensitive adhesive uses an acrylic polymer having a monomer unit of a (meth) acrylic acid alkyl ester as a main skeleton as a base polymer. Examples of the (meth) acrylic acid alkyl ester constituting the main skeleton of the acrylic polymer include those similar to those used for the acrylic pressure-sensitive adhesive composition forming the visual-viewing side pressure-sensitive adhesive layer. Moreover, as the copolymerization monomer and the ratio thereof, the same thing as the one used for the said acrylic pressure-sensitive adhesive composition can be mentioned.

The acrylic polymer can be produced by various known methods, and for example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo-based and peroxide-based agents can be used. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is 1 to 8 hours. Further, among the above-mentioned production methods, the solution polymerization method is preferable, and ethyl acetate, toluene and the like are generally used as the solvent for the acrylic polymer. The solution concentration is usually about 20 to 80% by weight.

Further, the pressure-sensitive adhesive can be a pressure-sensitive adhesive composition containing a cross-linking agent. As the cross-linking agent, the above-mentioned ones can be mentioned, but an isocyanate-based cross-linking agent is particularly preferable. The blending ratio of the acrylic polymer and the cross-linking agent is not particularly limited, but it is usually preferably about 0.001 to 20 parts by weight of the cross-linking agent (solid content) with respect to 100 parts by weight of the acrylic polymer (solid content). , 0.01 to 15 parts by weight is more preferable.

Further, the pressure-sensitive adhesive may include, if necessary, a pressure-imparting agent, a plasticizer, a glass fiber, a glass bead, a metal powder, a filler composed of other inorganic powders, a pigment, a colorant, a filler, and an antioxidant. Agents, ultraviolet absorbers, silane coupling agents and the like can be appropriately used, and various additives can be appropriately used without departing from the object of the present invention. Further, it may be used as a pressure-sensitive adhesive layer or the like containing fine particles and exhibiting light diffusivity. Examples of the silane coupling agent include those mentioned above.

The pressure-sensitive adhesive layer on the image display portion side is formed by applying the pressure-sensitive adhesive composition to various substrates such as a polarizing film or a release film and drying it. When the pressure-sensitive adhesive layer is formed on various substrates such as a release film, the pressure-sensitive adhesive layer can be bonded to a polarizing film and transferred. Examples of the method for applying the pressure-sensitive adhesive and the various base materials are the same as the method for applying the acrylic pressure-sensitive adhesive composition and the various base materials.

Further, in the coating step, the coating amount is controlled so that the formed pressure-sensitive adhesive layer has a predetermined thickness (thickness after drying). The thickness of the pressure-sensitive adhesive layer on the image display portion side is not particularly limited, but is preferably 1/2 or less, preferably 1/5 or less of the thickness of the pressure-sensitive adhesive layer on the visual viewing side. It is preferably 1/10 or less. Specifically, the thickness of the pressure-sensitive adhesive layer on the image display portion side is preferably about 1 to 100 μm, more preferably about 3 to 50 μm, and even more preferably about 5 to 30 μm.

In forming the pressure-sensitive adhesive layer on the image display portion side, the applied pressure-sensitive adhesive is dried. The drying temperature and drying time are not particularly limited and are appropriately set, but are preferably, for example, about 80 to 200 ° C. for 0.5 to 10 minutes.

When the pressure-sensitive adhesive layer on the image display portion side is exposed, the pressure-sensitive adhesive layer may be protected with a release film until it is put into practical use. The release film can be used as it is as a separator for a polarizing film with an adhesive layer, and can be simplified in terms of process.

(3) Polarizing film The polarizing film used in the present invention has a transparent protective film on both sides of the polarizing element and the polarizing element, and the transparent protective film on the visible side of the polarizing element (transparent protective film on the visible side) transmits at a wavelength of 380 nm. The rate is characterized by less than 6%.

(3-1) Visible Transparent Protective Film The transmittance of the visible transparent protective film used in the present invention at a wavelength of 380 nm is less than 6%, preferably 3% or less, and more preferably 2% or less. It is preferably 1% or less, and more preferably 1% or less. In the present invention, a higher degree of ultraviolet absorption ability is achieved by combining the visible side transparent protective film having a transmittance of less than 6% at a wavelength of 380 nm and the visible side adhesive layer (containing an ultraviolet absorber). It is something that can be done. Further, the lower limit of the transmittance of the transparent protective film on the visual recognition side at a wavelength of 380 nm is not particularly limited, and the smaller it is, the more preferable it is from the viewpoint of the ultraviolet absorbing function.

As the material for forming the transparent protective film on the visible side, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property and the like is 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, and styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin). Examples thereof include based polymers and polystyrene polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, and sulfone polymers. , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy polymer, or Blends of the polymers and the like are also mentioned as examples of polymers forming the transparent protective film. The transparent protective film can also be formed as a cured layer of a thermosetting type or ultraviolet curable type resin such as acrylic type, urethane type, acrylic urethane type, epoxy type and silicone type. Among these, the visible side transparent protective film is selected from the group consisting of a triacetyl cellulose film, an acrylic film (a film using an acrylic polymer), a polyethylene terephthalate film, and a cyclo-based or a polyolefin film having a norbornene structure. At least one kind of film is preferable, and a triacetyl cellulose film is more preferable.

The thickness of the transparent protective film on the visible side is not particularly limited, but is preferably 40 μm or less, more preferably 35 μm or less, and further preferably 30 μm or less. The lower limit of the thickness of the transparent protective film on the visible side is not particularly limited, but is preferably 1 μm or more. When the thickness of the transparent protective film on the viewing side is within the above range, the thickness of the polarizing film can be sufficiently reduced and the protective function of the polarizing element is not impaired, which is preferable.

It is preferable that the polarizing element, which will be described later, and the visible side protective film are in close contact with each other via a water-based adhesive or the like. Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, water-based polyurethanes, and water-based polyesters. In addition to the above, examples of the adhesive between the polarizing element and the transparent protective film on the visible side include an ultraviolet curable adhesive, an electron beam curable adhesive, and the like. The adhesive for an electron beam curable polarizing film exhibits suitable adhesiveness to the above-mentioned various visible side 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 the visible side to which the polarizing element is not adhered may be subjected to a hard coat layer, antireflection treatment, anti-sticking treatment, or treatment for the purpose of diffusion or anti-glare.

(3-2) Polarizer The polarizing element is not particularly limited, and various types can be used. As the substituent, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene / vinyl acetate copolymerization system partially saponified film, and a bicolor property of iodine or a bicolor dye are used. Examples thereof include a uniaxially stretched film by adsorbing a substance, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride. Among these, a polarizing element composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizing elements is not particularly limited, but is generally about 5 to 80 μm.

A polarizing element obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine to dye it and stretching it to 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution of potassium iodide or the like, which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, it is possible to clean the surface of the polyvinyl alcohol-based film and the blocking inhibitor, and by swelling the polyvinyl alcohol-based film, it also has the effect of preventing non-uniformity such as uneven dyeing. be. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. It can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, in the present invention, a thin polarizing element having a thickness of 10 μm or less can also be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizing element has less uneven thickness, excellent visibility, excellent durability because there is little dimensional change, and the thickness of the polarizing film can be reduced.

Typical examples of the thin polarizing element include Japanese Patent Application Laid-Open No. 51-06644, Japanese Patent Application Laid-Open No. 2000-338329, International Publication No. 2010/100917 Pamphlet, International Publication No. 2010/100917 Pamphlet, or Patent. Examples thereof include the thin polarizing film described in Japanese Patent Application Laid-Open No. 4751481 and Japanese Patent Application Laid-Open No. 2012-0756363. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a stretching resin base material in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without any trouble such as breakage due to stretching because it is supported by the stretching resin base material.

The thin polarizing film can be stretched at a high magnification and the polarization performance can be improved even in a manufacturing method including a step of stretching in a laminated state and a step of dyeing. , International Publication No. 2010/100917, or those obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in Japanese Patent Application Laid-Open No. 4751481 and Japanese Patent Application Laid-Open No. 2012-073563 are preferable, and particularly patented. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in a boric acid aqueous solution described in the specification of 4751481 and Japanese Patent Application Laid-Open No. 2012-073563.

(3-3) Transparent protective film on the image display side As the transparent protective film on the image display side, conventionally used transparent protective films can be appropriately used. Specifically, a transparent protective film formed of a material having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is preferable, and for example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate is preferable. , Cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethylmethacrylate, styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin), polycarbonate-based polymers and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, and sulfone polymers. , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy polymer, or Blends of the polymers and the like are also mentioned as examples of polymers forming the transparent protective film. The transparent protective film can also be formed as a cured layer of a thermosetting type or ultraviolet curable type resin such as acrylic type, urethane type, acrylic urethane type, epoxy type and silicone type.

The thickness of the protective film on the image display portion side can be appropriately determined, but is generally about 1 to 500 μm in terms of workability such as strength and handleability, and thin film property.

The polarizing element and the transparent protective film on the image display portion side are also usually in close contact with each other via a water-based adhesive or the like. Examples of the water-based adhesive include those mentioned above.

The surface of the transparent protective film on the image display side to which the polarizing element is not adhered may be subjected to a hard coat layer, antireflection treatment, anti-sticking treatment, or treatment for the purpose of diffusion or anti-glare.

2. 2. Image Display Device The image display device of the present invention is characterized in that the polarizing film with the pressure-sensitive adhesive layer of the present invention is used.

As an example of a specific configuration of the image display device, for example, as shown in FIGS. 2 to 4, a cover glass or a cover plastic 6 / a visible side adhesive layer 2a / a visible side transparent protective film 3a / a polarizing element 4 / Image display side transparent protective film 3b / Image display side adhesive layer 2b / Liquid crystal display (LCD) or organic EL display (OLED) 7 (FIG. 2); Cover glass or cover plastic 6 / Adhesive layer 8a / Sensor layer 9 / Visible adhesive layer 2a / Visible transparent protective film 3a / Polarizer 4 / Image display side transparent protective film 3b / Image display unit side adhesive layer 2b / Liquid crystal display (LCD) or organic EL display Device (OLED) 7 (FIG. 3); Cover glass or cover plastic 6 / Adhesive layer 8a / Sensor layer 9 / Adhesive layer 8b / Sensor layer 9 / Visible adhesive layer 2a / Visible transparent protective film 3a / Polarized As shown in the child 4 / transparent protective film 3b on the image display unit side / adhesive layer 2b on the image display unit side / liquid crystal display device (LCD) or organic EL display device (OLED) 7 (FIG. 4); The image display device that has been used can be mentioned. In the above-mentioned configuration, the polarizing film 1 with an adhesive layer of the present invention has "visual adhesive layer 2a / visible transparent protective film 3a / polarizing element 4 / image display side transparent protective film 3b / image display side adhesive". The portion of "agent layer 2b" is referred to, and a retardation film or the like may be included in addition to these. When a retardation film is included, specifically, the image display unit side adhesive layer 2b is laminated between the liquid crystal display device (LCD) or the organic EL display device (OLED) 7 via the adhesive layer. can do. Further, in laminating each layer, an adhesive layer and / or an adhesive layer can be appropriately used.

Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), electronic paper, and the like. Among these, a liquid crystal display device having the above-mentioned configuration, an organic EL (organic EL). An electroluminescence) display device or the like is preferable.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The parts and% in each example are based on weight.

Production Example 1 (Production of Acrylic Adhesive Composition (a-1))
Photopolymerization initiated into a monomer mixture composed 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). As an agent, 1-hydroxycyclohexylphenylketone (trade name: Irgacure 184, having an absorption band at a wavelength of 200 to 370 nm, manufactured by BASF) 0.035 part by weight, 2,2-dimethoxy-1,2-diphenylethane-1 -On (trade name: Irgacure 651, having an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF) After blending 0.035 parts by weight, viscosity (measurement conditions: BH viscosity meter No. 5 rotor, 10 rpm, measurement temperature) The mixture was irradiated with ultraviolet rays until the temperature reached about 20 Pa · s (30 ° C.) to obtain a prepolymer composition (polymerization rate: 8%) in which a part of the above-mentioned monomer components was polymerized. 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. And mixed to obtain an acrylic pressure-sensitive adhesive composition (a-1).

Production Example 2 (Production of Acrylic Adhesive Composition (a-2))
Polymerized into a monomer mixture composed of 72 parts by weight of 2-ethylhexyl acrylate (2EHA), 1 part by weight of methacrylic acid acrylate (MMA), 12 parts by weight of N-vinylpyrrolidone (NVP), and 15 parts by weight of hydroxyethyl acrylate (HEA). After 0.2 parts by weight of azobisbutylnitrile (AIBN) and 233 parts by weight of ethyl acetate were added as an initiator, a part of the above monomer components was polymerized by reacting at 60 ° C. for 7 hours under a nitrogen atmosphere. A partial polymer was obtained. Next, 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the partial polymer, and an isocyanate-based cross-linking agent (trade name: Takenate D110N, Mitsui) was used as a cross-linking agent. (Chemical Co., Ltd.) 0.21 part by weight was added to obtain an acrylic pressure-sensitive adhesive composition (a-2).

Production Example 3 (Manufacturing of the adhesive layer (B-1) on the image display side)
In a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, 95 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, 0.2 parts by weight of azobisisobutyronitrile as a polymerization initiator, and After adding 233 parts by weight of ethyl acetate, nitrogen gas was flowed and nitrogen substitution was performed for about 1 hour with stirring. Then, the flask was heated to 60 ° C. and reacted for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1.1 million.
To the above acrylic polymer solution (solid content is 100 parts by weight), trimethylolpropane tolylene diisocyanate (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.8 parts by weight as an isocyanate-based cross-linking agent. A pressure-sensitive adhesive composition (solution) was prepared by adding 0.1 part by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.).
The obtained pressure-sensitive adhesive composition solution was applied onto a 38 μm-thick separator (polyethylene terephthalate-based film whose surface had been peeled off) so that the dried thickness would be 12 μm, and dried at 100 ° C. for 3 minutes. The layer was applied to remove the solvent, and a pressure-sensitive adhesive layer was obtained. Then, it was heated at 50 ° C. for 48 hours to carry out a crosslinking treatment. Hereinafter, this pressure-sensitive adhesive layer is referred to as "image display portion side pressure-sensitive adhesive layer (B-1)".

Manufacturing Example 4 (Manufacturing of the adhesive layer (B-2) on the image display side)
The pressure-sensitive adhesive composition solution obtained in Production Example 3 was applied onto a 38 μm-thick separator (polyethylene terephthalate-based film whose surface was mold-released) so that the dried thickness would be 15 μm, and 100 A dry layer was allowed to be formed at ° C. for 3 minutes to remove the solvent, and a pressure-sensitive adhesive layer was obtained. Then, it was heated at 50 ° C. for 48 hours to carry out a crosslinking treatment. Hereinafter, this pressure-sensitive adhesive layer is referred to as "image display portion side pressure-sensitive adhesive layer (B-2)".

Example 1
(Manufacturing of adhesive composition with UV absorption function)
2,4-Bis- [{4- (4-ethylhexyloxy) -4-hydroxy, which was dissolved in the obtained acrylic pressure-sensitive adhesive composition (a-1) in butyl acrylate so as to have a solid content of 15%. } -Phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, "ultraviolet absorber 1" in Tables 1 and 2, manufactured by BASF Japan Ltd.) 1.4 weight Add 0.2 parts by weight of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: Irgacure 819, having absorption resistance at a wavelength of 200 to 450 nm, manufactured by BASF Japan Ltd.) and stirring. A pressure-sensitive adhesive composition having an ultraviolet absorbing function was obtained.

The pressure-sensitive adhesive composition with an ultraviolet absorbing function is applied onto a film that has been peeled off from a release film so that the thickness after forming the pressure-sensitive adhesive layer is 150 μm, and then the surface of the pressure-sensitive adhesive composition layer is applied. A release film was attached to. After that, ultraviolet irradiation was performed under the conditions of illuminance: 6.5 mW / cm ² , light intensity: 1500 mJ / cm ² , and peak wavelength: 350 nm to photo-cure the pressure-sensitive adhesive composition layer to obtain a visible-side pressure-sensitive adhesive layer (A-1). ) Was formed.

(Manufacturing of polarizing film (P-1))
A 25 μm-thick cycloolefin polymer (COP) film is attached to the visible side of a polarizing element made of a 5 μm-thick stretched polyvinyl alcohol film impregnated with iodine using a polyvinyl alcohol-based adhesive, and an image of the polarizing element is displayed. A 20 μm-thick acrylic film was laminated on the surface of the portion using a polyvinyl alcohol-based adhesive to obtain a polarizing film (P-1). The degree of polarization of the polarizing film was 99.995.

(Manufacturing of polarizing film with adhesive layer)
The visible side pressure-sensitive adhesive layer (A-1) was laminated on the visible side of the polarizing film (P-1) (that is, the surface of the cycloolefin polymer (COP) film having a thickness of 25 μm). An image display portion side adhesive layer (B-1) is laminated on the image display portion side surface of the polarizing film (P-1) (that is, the surface of an acrylic film having a thickness of 20 μm), and further, a retardation film (that is, a retardation film (P-1)) is laminated. The thickness: 56 μm, material: polycarbonate) and the pressure-sensitive adhesive layer (B-2) on the image display portion side were laminated to form a polarizing film with a pressure-sensitive adhesive layer. The obtained polarizing film with an adhesive layer is a visible side adhesive layer (A-1) / polarizing film (P-1) / image display unit side adhesive layer (B-1) / retardation film / image display unit. It had the structure of the side pressure-sensitive adhesive layer (B-2).

Examples 2-3
The pressure-sensitive adhesive layer is the same as in Example 1 except that the types of the acrylic pressure-sensitive adhesive composition, the amount of the ultraviolet absorber 1 added, and the thickness after forming the pressure-sensitive adhesive layer on the visual side are as shown in Table 1. A polarizing film was formed.

Example 4
The adhesive layer is attached in the same manner as in Example 1 except that the adhesive layer on the visible side is changed from the adhesive layer on the visible side (A-1) to the adhesive layer on the visible side (A-2) obtained below. A polarizing film was formed.

(Manufacturing of visible adhesive layer (A-2))
2,4-Bis- [{4- (4-ethylhexyloxy)] dissolved in ethyl acetate so as to have a solid content of 15% in the acrylic pressure-sensitive adhesive composition (a-2) obtained in Production Example 2. -4-Hydroxy} -Phenyl] -6- (4-Methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan Ltd.) 1.4 parts by weight is added and stirred to obtain ultraviolet rays. A pressure-sensitive adhesive composition with an absorption function was obtained.

The pressure-sensitive adhesive composition with an ultraviolet absorbing function is applied onto a film that has been peeled off from a release film so that the thickness after forming the pressure-sensitive adhesive layer is 150 μm, and is applied at 60 ° C. for 2 minutes and at 120 ° C. for 2 minutes. After being dried for a minute, the peeled film was bonded to form a visible side adhesive layer (A-2).

Examples 5-6
A polarizing film with an adhesive layer was formed in the same manner as in Example 4, except that the thickness of the adhesive layer on the visible side after formation and the adhesive layer on the image display portion side were as shown in Table 1.

Example 7
(Manufacturing of visible adhesive layer (A-3))
2,4-Bis- [{4- (4-ethylhexyloxy)] dissolved in butyl acrylate so as to have a solid content of 15% in the acrylic pressure-sensitive adhesive composition (a-1) obtained in Production Example 1. -4-Hydroxy} -Phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan Ltd.) 0.7 parts by weight, Solvent Yellow163 (KP Last Yellow MK) , "Ultraviolet absorber 2" in Table 2, 0.2 parts by weight of Kiwa Chemical Industry Co., Ltd., bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: Irgacure 819, wavelength) A pressure-sensitive adhesive composition having an ultraviolet absorbing function was obtained by adding 0.2 parts by weight of (manufactured by BASF Japan, Inc.) having an absorption resistance at 200 to 450 nm and stirring.

The pressure-sensitive adhesive composition with an ultraviolet absorbing function is applied onto a film that has been peeled off from a release film so that the thickness after forming the pressure-sensitive adhesive layer is 150 μm, and then the surface of the pressure-sensitive adhesive composition layer is applied. A release film was attached to. Thereafter, illuminance: 6.5 mW / cm ^2, light quantity: 3000 mJ / cm ^2, the peak wavelength irradiated with ultraviolet rays under the condition of 350 nm, the pressure-sensitive adhesive composition layer by light-curing, the visible side pressure-sensitive adhesive layer (A-3 ) Was formed.

The adhesive layer is attached in the same manner as in Example 1 except that the adhesive layer on the visible side is changed from the adhesive layer on the visible side (A-1) to the adhesive layer on the visible side (A-3) obtained above. A polarizing film was formed.

Comparative Example 1
A polarizing film with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive layer (A-1) on the visible side, the retardation film, and the adhesive layer (B-2) on the image display portion side were not formed. Formed.

Comparative Example 2
A polarizing film with an adhesive layer was formed in the same manner as in Example 1 except that the adhesive layer (A-1) on the visible side was not formed.

Comparative Examples 3 and 4
A polarizing film with an adhesive was formed in the same manner as in Examples 1 and 4 except that the ultraviolet absorber was not added to the adhesive layers (A-1) and (A-2) on the visible side.

Comparative Example 5
(Manufacturing of polarizing film (P-2))
A 25 μm-thick triacetyl cellulose film is attached to the visible side of a polarizing element made of a stretched polyvinyl alcohol film having a thickness of 12 μm impregnated with iodine using a polyvinyl alcohol-based adhesive, and the surface of the polarizing element on the image display side side. An acrylic film having a thickness of 20 μm was laminated with a polyvinyl alcohol-based adhesive to obtain a polarizing film (P-2). The degree of polarization of the polarizing film was 99.995.

In Example 2, a polarizing film with an adhesive was formed in the same manner as in Example 2 except that the polarizing film (P-1) was changed to the polarizing film (P-2).

The obtained pressure-sensitive adhesive layer and the polarizing film with the pressure-sensitive adhesive layer were evaluated as follows.

<Polymerization rate>
The release film of the visible side adhesive layer obtained in Examples and Comparative Examples was peeled off, and only the visible side adhesive layer was placed on the weighed aluminum petri dish. The weight of (aluminum petri dish + adhesive layer on the visual side) was measured, and the weight of the adhesive layer before drying was determined. After drying at 130 ° C. for 2 hours and cooling at room temperature for about 20 minutes, the weight of (aluminum petri dish + adhesive) was measured again to determine the weight of the adhesive layer on the visible side after drying. The polymerization rate was calculated by the following formula.

<Gel fraction>
Approximately 0.1 g was collected from the visual adhesive layer obtained in Examples and Comparative Examples, and wrapped in a porous tetrafluoroethylene sheet (trade name: NTF1122, manufactured by Nitto Denko KK) with an average pore size of 0.2 μm. After that, it was tied with a kite string, and the weight at that time was measured (Zg), and the weight was taken as the weight before immersion. The weight before immersion is the total weight of the visible side pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer collected above), the tetrafluoroethylene sheet, and the kite string. The total weight of the tetrafluoroethylene sheet and the kite string was also measured (Yg). Next, the adhesive layer on the visual side was wrapped with a tetrafluoroethylene sheet and tied with a kite string (referred to as a "sample"), placed in a 50 mL container filled with ethyl acetate, and allowed to stand at 23 ° C. for 7 days. Then, the sample (after treatment with ethyl acetate) was taken out from the container, transferred to an aluminum cup, dried in a dryer at 130 ° C. for 2 hours to remove ethyl acetate, and then weighed (Xg). The weight was taken as the weight after immersion. The gel fraction was calculated from the following formula.
Gel fraction (% by weight) = (XY) / (ZY) x 100

<Measurement of transmittance and b * value of the adhesive layer on the visual side>
The release film of the visible side adhesive layer obtained in Examples and Comparative Examples was peeled off, the visible side adhesive layer was attached to a measuring jig, and a spectrophotometer (product name: U4100, Hitachi High-Technologies Corporation) was attached. Measured by Technologies). The transmittance was measured at wavelengths of 380 nm, 400 nm, and 420 nm (however, the transmittance of 420 nm was measured only in Examples 2 and 7).

<Residual stress>
A test piece was prepared by cutting out a width of 30 mm and a length of 50 mm from the visual adhesive layer obtained in Examples and Comparative Examples and forming them into a cylinder. This was installed with a chuck spacing of 20 mm, and the test piece was pulled by 60 mm (300%) at a tensile speed of 200 mm / min (the chuck spacing after tension was 80 mm). It was fixed (held) for 300 seconds at a position pulled by 60 mm, and the stress value (N) after 300 seconds was measured. The residual stress was calculated by the following formula.
Residual stress after 300 seconds = Stress value after 300 seconds (N) / (4 x thickness of test piece / 10)

<Optical reliability>
The visible side adhesive layer obtained in Examples 1 to 7 and Comparative Examples 3 to 5 was attached to the COP film of the polarizing film (P-1) used in Example 1. Further, a 56 μm retardation film (manufactured by Nitto Denko KK) with a 15 μm adhesive was attached to the opposite side (acrylic film side) of the polarizing film to which the visible adhesive layer was attached. Both sides of the sample are bonded with glass (trade name: S200200, thickness: 1.3 mm, size: 45 mm × 50 mm, manufactured by Matsunami Glass Ind. Co., Ltd.) and autoclaved (atmospheric pressure: 0.5 MPa, temperature:). 50 ° C.) was carried out for 15 minutes. Then, it was put under the following various reliability conditions, and the transmittance was measured with a spectral transmittance measuring device (product name: DOT-3, manufactured by Murakami Color Technology Laboratory Co., Ltd.). The amount of change in transmittance from the initial stage was calculated. It was evaluated according to the following evaluation criteria.
(Various reliability conditions)
(Condition 1) 85 ° C x 500h
(Condition 2) 60 ° C, 95% x 500h
(Condition 3) Heat shock (HS) (-40 ° C to 85 ° C) x 300 cycles (Condition 4) UV irradiation x ^{100 h, illuminance: 500 W / cm 2} (300 to 700 nm), environmental temperature: 60 to 65 ° C, Environmental humidity: 50%
(Condition 5) Under Xenon irradiation x 300 h, illuminance: 2.40 W / cm ² (420 nm), environmental temperature: 50 ° C., environmental humidity: 30%
(Evaluation criteria)
◯: The amount of change in transmittance is 2.0% or less.
Δ: The amount of change in transmittance exceeds 2.0% and is 3.0% or less.
X: The amount of change in transmittance exceeds 3.0%.

<Glue stain, dimensional accuracy, edge appearance>
The polarizing film with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 25 mm × 30 mm with a super cutter. Then, by using an end face processing machine (manufactured by Megalo Technica Co., Ltd.), the four sides of the cut piece were cut by 0.05 mm to prepare a sample. For glue stains, the side surface of the sample was visually checked to confirm the presence or absence of glue stains. The dimensional accuracy and the appearance of the edges were observed with an optical microscope and evaluated according to the following evaluation criteria.
(Dimensional accuracy)
○: Within ± 0.3 mm ×: Exceeds ± 0.3 mm (edge appearance)
◯: When there is no stickiness at the end when touched by hand ×: When there is stickiness at the end when touched by hand

<Curl measurement>
The sample cut into 50 mm × 40 mm was placed on a flat desk, and the curl was measured with a feeler gauge.
(curl)
◯: Within ± 1.0 mm Δ: Greater than ± 1.0 mm, within ± 2.0 mm ×: Greater than ± 2.0 mm

In Table 1, P-1 is a polarizing film (P-1), P-2 is a polarizing film (P-2), and a-1 is an acrylic pressure-sensitive adhesive composition obtained in Production Example 1. (A-1), a-2 is the acrylic pressure-sensitive adhesive composition (a-2) obtained in Production Example 2, and the ultraviolet absorber 1 is 2,4-bis- [{4- (4). -Ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan Ltd.), UV absorber 2 is Solvent Yellow163 (KP Last Yellow MK, manufactured by Kiwa Chemical Industry Co., Ltd.), B-1 is the image display unit side adhesive layer (B-1) obtained in Production Example 3, and B-2 is a production example. The adhesive layer (B-2) on the image display side obtained in 4 is shown.

1 Polarizing film with adhesive layer 2a Adhesive layer on the visible side 2b Adhesive layer on the image display side 3a Transparent protective film on the visible side 3b Transparent protective film on the image display part 4 Polarizer 5 Polarizing film 6 Cover glass or cover plastic 7 Liquid crystal display Device (LCD) or organic EL display device (OLED)
8a, 8b Adhesive layer 9 Sensor layer

Claims (9)

A polarizing film with an adhesive layer used on the visual side of an image display device in an image display device.
The polarizing film with an adhesive layer has an adhesive layer on both sides of the polarizing film and the polarizing film.
The polarizing film has a polarizing element and a transparent protective film on both sides of the polarizing element.
The transmittance of the transparent protective film on the visible side of the polarizing element at a wavelength of 380 nm is less than 6%.
The transparent protective film on the visible side of the polarizing element is at least one film selected from the group consisting of a triacetyl cellulose film, a polyethylene terephthalate film, and a polyolefin film having a cyclo-based or norbornene structure.
Neither the transparent protective film on the visual side of the polarizing element nor the transparent protective film on the image display portion side of the polarizing element is a triacetyl cellulose film.
The adhesive layer on the visible side of the polarizing film contains an ultraviolet absorber and a dye, and contains.
A polarizing film with an adhesive layer, wherein the adhesive layer on the visual side of the polarizing film has an ultraviolet absorbing function. The polarizing film with an adhesive layer according to claim 1, wherein the thickness of the transparent protective film on the visual side of the polarizing element is 40 μm or less. The adhesive according to claim 1 or 2, wherein the thickness of the pressure-sensitive adhesive layer on the visible side of the polarizing film is at least twice the thickness of the pressure-sensitive adhesive layer on the image display portion side of the polarizing film. Polarizing film with agent layer. One of claims 1 to 3, wherein the pressure-sensitive adhesive layer on the visible side of the polarizing film has a transmittance of 9% or less at a wavelength of 380 nm and a transmittance of 60% or more at a wavelength of 400 nm. The polarizing film with an adhesive layer described in 1. One of claims 1 to 3, wherein the pressure-sensitive adhesive layer on the visible side of the polarizing film has a transmittance of 9% or less at a wavelength of 380 nm and a transmittance of 75% or less at a wavelength of 420 nm. The polarizing film with an adhesive layer described in 1. The polarizing film with an adhesive layer according to any one of claims 1 to 4, wherein the b * value of the adhesive layer on the visual side of the polarizing film is 3.0 or less. The polarizing film with a pressure-sensitive adhesive layer according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive layer on the visible side of the polarizing film contains an acrylic polymer as a base polymer. The polarizing film with an adhesive layer according to any one of claims 1 to 7, wherein the polarizing film is used in a liquid crystal display device or an organic EL display device. An image display device according to any one of claims 1 to 8, wherein the polarizing film with an adhesive layer is used on the visual side of the image display unit.

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