JP2022003390A - Polarizing film having optical functional layer and liquid crystal display device - Google Patents

Abstract

To provide a polarizing film having an optical functional layer that has excellent aging stability and has an optical functional layer containing a coloring matter capable of maintaining a wider color gamut by the coloring matter.SOLUTION: In a polarizing film having an optical functional layer that has an optical functional layer A containing a coloring matter and a polyvinyl alcohol-based polarizer P, a distance between the optical functional layer A and the polyvinyl alcohol-based polarizer P is 45 μm or less. The polarizing film having an optical functional layer has excellent aging stability and has an optical functional layer containing a coloring matter capable of maintaining a wider color gamut by the coloring matter.SELECTED DRAWING: Figure 1

Description

The present invention relates to a polarizing film with an optical functional layer having an optical functional layer having a dye and a polarizing film having a polyvinyl alcohol-based polarizing element. The polarizing film with an optical functional layer may form an image display device such as a liquid crystal display device (LCD) or an organic EL display device alone or as an optical film in which the polarizing film with an optical functional layer is laminated.

In an image display device or the like, it is indispensable to arrange polarizing elements on both sides of a liquid crystal cell due to the image forming method, and generally, a polarizing film is attached. When the polarizing film is attached to the liquid crystal cell, an adhesive is usually used. Further, in order to reduce the loss of light, the polarizing film and the liquid crystal cell are usually adhered to each other by using an adhesive. In such a case, the pressure-sensitive adhesive has an advantage that a drying step is not required to fix the polarizing film. Therefore, the pressure-sensitive adhesive is polarized light with a pressure-sensitive adhesive layer previously provided as a pressure-sensitive adhesive layer on one side of the polarizing film. Film is commonly used.

Further, it has been proposed to give an arbitrary hue to a polarizing film by adding a dye or a pigment to the pressure-sensitive adhesive layer to obtain a high-contrast liquid crystal display (Patent Document 1). In recent years, image display devices are required to have brightness and vividness (that is, wide color gamut), and organic EL display devices (OLEDs) are attracting attention. However, liquid crystal display devices also have wide color gamut. Is required. For example, as a method for widening the color gamut of a liquid crystal display device, a polarizing film is applied to one or both sides of the liquid crystal cell via an adhesive layer containing a dye showing an absorption maximum wavelength in a specific wavelength (560 to 610 nm) range. It has been proposed to stack them (Patent Documents 2 and 3).

Jitsuto No. 3052812 specification Japanese Unexamined Patent Publication No. 2011-039093 Japanese Unexamined Patent Publication No. 2014-092611

As described above, the dye can be contained in the pressure-sensitive adhesive layer, and can also be contained in the film layer applied to the optical member. As described above, by incorporating the dye in the resin layer such as the film layer or the pressure-sensitive adhesive layer, the optical functional layer containing the dye can be formed. However, since the optical functional layer contains a dye, the dye in the optical functional layer deteriorates with time from the viewpoint of moisture permeability of the resin layer that is the base of the optical functional layer, and the optical functional layer Gradually fades. In particular, when the optical functional layer is a pressure-sensitive adhesive layer containing a dye, the durability of the pressure-sensitive adhesive layer is not sufficient from the viewpoint of moisture permeability, and the pressure-sensitive adhesive layer initially colored by the dye is used. Even if there is, it will gradually fade. As described above, when the dye in the optical functional layer (particularly, the pressure-sensitive adhesive layer) deteriorates with time, it is difficult to maintain the wide color gamut by the dye.

An object of the present invention is to provide a polarizing film with an optical functional layer having an optical functional layer containing a dye, which has good stability over time and can maintain a wide color gamut due to the dye.

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 optical functional layer having an optical functional layer containing a dye on at least one side of a polarizing film having a polyvinyl alcohol-based polarizing element, and contains the polyvinyl alcohol-based polarizing element and the dye. The present invention relates to a polarizing film with an optical functional layer, characterized in that the distance from the optical functional layer is 45 μm or less. The distance from the optical functional layer to the polyvinyl alcohol-based polarizing element is preferably 25 μm or less.

In the polarizing film with an optical functional layer, the pressure-sensitive adhesive layer with the polyvinyl alcohol-based polarizing element can be directly laminated.

In the polarizing film with an optical functional layer, at least one layer having no dye having a thickness of 45 μm or less can be provided between the pressure-sensitive adhesive layer and the polyvinyl alcohol-based polarizing element.

In the above polarizing film with an optical functional layer, the polyvinyl alcohol-based polarizer, it is preferable oxygen permeability is less than ^{1 [cm 3 / (m 2} · 24h · atm)].

In the polarizing film with an optical functional layer, a dye having a maximum absorption wavelength in at least one of a wavelength range of 470 to 510 nm and a wavelength range of 570 to 610 nm can be used.

In the polarizing film with an optical functional layer, a tetraazaporphyrin-based dye can be used as the dye.

In the polarizing film with an optical functional layer, it is preferable that the dye is contained in an amount of 0.01 to 5 parts by weight with respect to 100 parts by weight of the base polymer forming the resin layer of the optical functional layer.

In the polarizing film with an optical functional layer, the pressure-sensitive adhesive layer containing the dye is preferably 25 μm or less in thickness.

The present invention also relates to an image display device having the polarizing film with an optical functional layer.

The polarizing film with an optical functional layer of the present invention has an optical functional layer containing a dye. The optical functional layer can adjust the overall hue of the liquid crystal display device by absorbing light of a part of the wavelength by the dye, and can improve the vividness by widening the color gamut. In particular, a dye having a maximum absorption wavelength in at least one of a wavelength range of 470 to 510 nm and a wavelength range of 570 to 610 nm is a color in a wavelength range other than RGB (wavelength range 470 to 510 nm and / or wavelength range 570 to 610 nm). It is possible to absorb the unnecessary light emission that is unnecessary for expression and suppress the unnecessary light emission, which is effective for widening the color range.

It was found that the fading of the dye in the optical functional layer containing the dye is caused by oxygen existing in the atmosphere or the resin invading the optical functional layer and being activated by heat to attack the dye. rice field. Oxygen is considered to enter from the upper, lower, left and right surfaces of the pressure-sensitive adhesive layer.

In the polarizing film with an optical functional layer of the present invention, the optical functional layer containing the dye is applied to a polarizing film using a polyvinyl alcohol-based polarizing element. The polyvinyl alcohol-based polarizing element has a low oxygen permeability and can prevent oxygen from entering the optical functional layer from the upper surface or the lower surface of the optical functional layer containing the dye. The polarizing film with an optical functional layer of the present invention can be used by using a separator or the like having a low oxygen transmittance on the other surface of the optical functional layer until the specific use. Can be applied to an adherend having low oxygen permeability such as glass to prevent oxygen from entering the optical functional layer, suppress fading (decomposition) of the dye, and stabilize over time. It is possible to provide an optical functional layer capable of maintaining a wide color gamut.

Further, in the polarizing film with an optical functional layer of the present invention, the optical functional layer containing the dye and the polyvinyl alcohol-based polarizing element are laminated so that the distance between them is 45 μm or less. By setting the distance to 45 μm or less, oxygen entering from the end of the polarizing film with an optical functional layer can be prevented, and fading (decomposition) of the dye is suppressed even at the end of the polarizing film with an optical functional layer. Therefore, it is possible to maintain a wide color gamut stably over time.

It is sectional drawing which shows schematic outline of the polarizing film with an optical functional layer of this invention. It is sectional drawing which shows typically one Embodiment of the polarizing film with an optical functional layer of this invention. It is sectional drawing which shows typically one Embodiment of the polarizing film with an optical functional layer of this invention. It is sectional drawing which shows typically one Embodiment of the polarizing film with an optical functional layer of this invention.

Hereinafter, embodiments of the polarizing film with an optical functional layer of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments of the drawings.

As shown in FIG. 1, the polarizing film with an optical functional layer of the present invention has an optical functional layer A containing a polyvinyl alcohol-based polarizing element P and a dye. The polyvinyl alcohol-based polarizing element P and the optical functional layer A are laminated so that the distance x between them is 45 μm or less. The shorter the distance x, the more oxygen can be prevented from entering from the end. The distance x is preferably 25 μm or less, more preferably 10 μm or less, further preferably 5 μm or less, and further preferably 1 μm or less.

FIG. 2 shows a case where the polyvinyl alcohol-based polarizing element P and the optical functional layer A are directly laminated (x = 0 μm). Note that FIG. 2 illustrates the case of a polarizing film (single protective polarizing film) having a transparent protective film F on one side (the side on which the optical functional layer A is not provided) of the polyvinyl alcohol-based polarizing element P. Further, FIG. 2 illustrates a case where the base material S is provided on the optical functional layer A, as the base material S used until the specific use of the polarizing film with the optical functional layer. Examples include a separator, a vapor-deposited film, and the like. Specific examples include glass, a transparent substrate with a thin-film deposition layer, and the like.

Further, in FIG. 3, in the embodiment of FIG. 2, a case where a layer B having a thickness of 45 μm or less is provided between the polyvinyl alcohol-based polarizing element P and the optical functional layer A is exemplified. In FIG. 3, the case where the layer B is one layer is exemplified, but the layer B can be a combination of a plurality of layers. Examples of the layer B include an adhesive layer, a film layer, and the like. The thickness of the layer B is in the range of 45 μm or less, and can be designed according to the characteristics of each layer.

Further, in FIG. 4, in the embodiment of FIG. 2, the polyvinyl alcohol-based polarizing element P and the optical functional layer A are directly (x = 0 μm) laminated, and further, a layer is further formed on the optical functional layer A. The case of having C is exemplified. The case where the layer C is one layer is exemplified, but the layer C can be a combination of a plurality of layers. Examples of the layer C include an adhesive layer, a surface treatment layer (hard coat layer, antiglare treatment layer, antireflection layer, etc.) and the like. The thickness of the layer C is in the range of 45 μm or less, and can be designed according to the characteristics of each layer. Layer C can also be applied in combination with layer B.

The polarizing film with an optical functional layer of the present invention has a polarizing film having a polyvinyl alcohol-based polarizing element and an optical functional layer containing a dye. Hereinafter, each member will be described.

<Optical functional layer>
The optical functional layer of the present invention is not particularly limited as long as it is a resin layer containing a dye. Examples of the resin layer include a film layer and an adhesive layer. The optical functional layer can be formed from a composition containing a base polymer and a dye.

<Dye>
Various dyes can be used as the dye contained in the optical functional layer of the present invention. Examples of the dye include various compounds such as tetraazaporphyrin-based, porphyrin-based, cyanine-based, azo-based, pyrromethene-based, squarylium-based, xanthene-based, oxonor-based, and Skualine-based. From the viewpoint of widening the color gamut, the dye is preferably a tetraazaporphyrin-based dye, a porphyrin-based dye, a cyanine-based dye, a squalium-based dye, or a skualine-based dye, and particularly preferably a tetraazaporphyrin-based dye. Specifically, the dye is disclosed in Japanese Patent Application Laid-Open No. 2011-116818. As the dye, only one kind may be used, or two or more kinds may be used in combination.

The dye preferably has a maximum absorption wavelength in at least one of a wavelength range of 470 to 510 nm and a wavelength range of 570 to 610 nm. The dye having a maximum absorption wavelength in the wavelength range can absorb light emission unnecessary for color expression and suppress the light emission, which is effective for widening the color gamut. As the dye having the maximum absorption wavelength in the wavelength range, a tetraazaporphyrin-based dye can be preferably used. For example, as a dye showing a maximum absorption wavelength in the wavelength range of 570 to 610 nm, a tetraazaporphyrin-based compound manufactured by Yamamoto Kasei Co., Ltd. (trade names: PD-320, PD311) and a tetraazaporphyrin-based compound manufactured by Yamada Chemical Industry Co., Ltd. (trade names: PD-320, PD311) Product name: FDG-007) and the like. The maximum absorption wavelength of the dye was measured by a spectrophotometer (V-570 manufactured by JASCO Corporation).

The content of the dye in the optical functional layer of the present invention is adjusted by the absorption wavelength range of the dye, the absorption coefficient and the type of the base polymer, but is usually 0.01 to 5 parts by weight with respect to 100 parts by weight of the base polymer. It is preferably present, more preferably 0.05 to 3 parts by weight, still more preferably 0.1 to 1 part by weight. In particular, the above range is preferable when a tetraazaporphyrin-based dye is used.

<Adhesive layer>
Examples of the optical functional layer of the present invention include a pressure-sensitive adhesive layer containing a dye, and the pressure-sensitive adhesive layer can be formed from a pressure-sensitive base polymer and a pressure-sensitive adhesive composition containing a dye. There are no particular restrictions on the type of adhesive base polymer, but for example, rubber-based polymers, (meth) acrylic-based polymers, silicone-based polymers, urethane-based polymers, vinyl alkyl ether-based polymers, polyvinyl alcohol-based polymers, and polyvinylpyrrolidone-based polymers. Various polymers such as polymers, polyacrylamide-based polymers, and cellulose-based polymers can be mentioned.

The pressure-sensitive adhesive composition of the present invention contains a pressure-sensitive base polymer as a main component. The main component refers to the component having the highest content ratio in the total solid content contained in the pressure-sensitive adhesive composition, and is, for example, a component accounting for more than 50% by weight of the total solid content contained in the pressure-sensitive adhesive composition. Further, it refers to a component that accounts for more than 70% by weight.

Among these adhesive base polymers, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness, and adhesive adhesive properties, and having excellent weather resistance and heat resistance are preferably used. A (meth) acrylic polymer is preferably used to exhibit such characteristics. Hereinafter, an acrylic pressure-sensitive adhesive using a (meth) acrylic polymer containing an alkyl (meth) acrylate as a monomer unit as a base polymer, which is a material for forming the pressure-sensitive adhesive layer, will be described.

<(Meta) acrylic polymer>
The (meth) acrylic polymer usually contains an alkyl (meth) acrylate as a main component as a monomer unit. In addition, (meth) acrylate means acrylate and / or methacrylate, and has the same meaning as (meth) of the present invention.

Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer include linear or branched alkyl groups having 1 to 18 carbon atoms. These can be used alone or in combination. The average number of carbon atoms of these alkyl groups is preferably 3 to 9.

Further, from the viewpoints of adhesive properties, durability, adjustment of phase difference, adjustment of refractive index, etc., an alkyl (meth) acrylate containing an aromatic ring such as phenoxyethyl (meth) acrylate and benzyl (meth) acrylate is used. be able to.

One or more of the (meth) acrylic polymers having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group for the purpose of improving adhesiveness and heat resistance. The copolymerization monomer of can be introduced by copolymerization. Specific examples of such a copolymerizable monomer include, for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6 (meth) acrylate. Hydroxyl group-containing monomers such as −hydroxyhexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate. Carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid; acid anhydrides such as maleic anhydride and itaconic anhydride. Material-containing monomer; Acrylic acid caprolactone adduct; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, ( Meta) Examples thereof include sulfonic acid group-containing monomers such as acryloyloxynaphthalene sulfonic acid; and phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate.

Further, (N-substituted) amides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth) acrylamide. Monomer; (meth) Alkylaminoalkyl-acrylic acid monomer such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate; (meth) acrylic (Meta) Acrylic acid alkoxyalkyl-based monomers such as methoxyethyl acid and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N-( Meta) Succinimide-based monomers such as acryloyl-8-oxyoctamethylenesuccinimide and N-acryloylmorpholin; maleimide-based monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; Italonimide-based monomers such as imide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide are also used for modification. As an example of the monomer of.

Further, as modified monomers, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholin, N- Vinyl-based monomers such as vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate-based monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Glycol-based acrylic ester monomers such as (meth) polyethylene glycol acrylate, (meth) polypropylene glycol acrylate, (meth) methoxyethylene glycol acrylate, (meth) methoxypolypropylene glycol acrylate; (meth) tetrahydrofurfuryl acrylate, Acrylic acid ester-based monomers such as fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate can also be used. Further, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

Further, as a copolymerizable monomer other than the above, 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.

Examples of the copolymerization monomer include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, and neo. Pentyl glycol di (meth) acrylate, trimethyl propantri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate , Caprolactone-modified dipentaerythritol Hexa (meth) Acrylate and other (meth) acrylic acids and polyhydric alcohols such as esterified products such as (meth) acryloyl groups and vinyl groups and other unsaturated double bonds having two or more unsaturated double bonds. Polyester (meth) acrylates and epoxys (meth) acrylates and epoxys in which two or more unsaturated double bonds such as (meth) acryloyl groups and vinyl groups are added as functional groups similar to the monomer components to the skeletons of sex monomers, polyesters, epoxys, urethanes, etc. Meta) acrylate, urethane (meth) acrylate and the like can also be used.

The (meth) acrylic polymer contains an alkyl (meth) acrylate as a main component in the weight ratio of all the constituent monomers, and the ratio of the copolymerized monomer in the (meth) acrylic polymer is not particularly limited, but the above-mentioned copolymer. The proportion of the polymerized monomer is preferably about 0 to 20%, about 0.1 to 15%, and more preferably about 0.1 to 10% in terms of the weight ratio of all the constituent monomers.

Among these copolymerizable monomers, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferably used from the viewpoint of adhesiveness and durability. A hydroxyl group-containing monomer and a carboxyl group-containing monomer can be used in combination. These copolymerizable monomers become reaction points with the cross-linking agent when the pressure-sensitive adhesive composition contains the cross-linking agent. Since the hydroxyl group-containing monomer, the carboxyl group-containing monomer and the like are highly reactive with the intermolecular cross-linking agent, they are preferably used for improving the cohesiveness and heat resistance of the obtained pressure-sensitive adhesive layer. The hydroxyl group-containing monomer is preferable in terms of reworkability, and the carboxyl group-containing monomer is preferable in terms of achieving both durability and reworkability.

When the hydroxyl group-containing monomer is contained as the copolymerization monomer, the ratio thereof is preferably 0.01 to 15% by weight, more preferably 0.03 to 10% by weight, and further preferably 0.05 to 7% by weight. preferable. When the carboxyl group-containing monomer is contained as the copolymerization monomer, the ratio thereof is preferably 0.05 to 10% by weight, more preferably 0.1 to 8% by weight, and further preferably 0.2 to 6% by weight. preferable.

As the (meth) acrylic polymer of the present invention, those having a weight average molecular weight in the range of 500,000 to 3,000,000 are usually used. Considering durability, particularly heat resistance, it is preferable to use one having a weight average molecular weight of 700,000 to 2.7 million. Further, it is preferably 800,000 to 2.5 million. If the weight average molecular weight is less than 500,000, it is not preferable in terms of heat resistance. Further, when the weight average molecular weight is larger than 3 million, a large amount of diluting solvent is required to adjust the viscosity for coating, which is not preferable because it increases the cost. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

For the production of such (meth) acrylic polymers, known production methods such as solution polymerization, radiation polymerization such as UV polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations 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.

In solution polymerization, 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.

The polymerization initiator, chain transfer agent, emulsifier and the like used for 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 of the (meth) acrylic polymer used is appropriately adjusted according to these types.

Examples of the radical polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, and 2,2'-azobis [2- (5-methyl-). 2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutyramidin), 2, Azo-based initiators such as 2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057), persulfates such as potassium persulfate and ammonium persulfate. Salt, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexyl Peroxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di ( Peroxides such as 4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butylhydroperoxide, hydrogen peroxide, etc. Examples include system initiators, redox-based initiators in which a peroxide and a reducing agent such as a combination of a persulfate and sodium hydrogen sulfite, and a combination of a peroxide and sodium ascorbate are combined, but the present invention is limited to these. It is not something that will be done.

The radical polymerization initiator may be used alone or in combination of two or more, but the total content is 0.005 to 1 weight by weight based on 100 parts by weight of the monomer. The amount is preferably about 0.02 to 0.5 parts by weight, and more preferably about 0.02 to 0.5 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 0.1 part 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 Asahi Denko Co., Ltd.) and the like. Since the reactive emulsifier is incorporated into the polymer chain after polymerization, it has good water resistance and is preferable. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight from the viewpoint of polymerization stability and mechanical stability with respect to 100 parts by weight of the total amount of the monomer components.

<Crosslinking agent>
Further, in the present invention, a cross-linking agent can be contained in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer having a dye. As the cross-linking agent, an organic cross-linking agent or a polyfunctional metal chelate can be used. Examples of the organic cross-linking agent include an isocyanate-based cross-linking agent, a peroxide-based cross-linking agent, an epoxy-based cross-linking agent, and an imine-based cross-linking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinated to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti and the like. Can be mentioned. Examples of the atom in the organic compound having a covalent bond or a coordination bond include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

Examples of the compound related to the isocyanate-based cross-linking agent include isocyanate monomers such as tolylene diisocyanate, chlorphenylene diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate, and these isocyanate monomers. Examples include isocyanate compounds added with trimethylolpropane, isocyanurates, bullet-type compounds, and urethane prepolymer-type isocyanates that have been subjected to an addition reaction such as polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, and polyisoprene polyols. be able to. Particularly preferred is a polyisocyanate compound, which is one selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived thereto. Here, the polyisocyanate compound selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate or derived thereof includes hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and polyol modification. Hexamethylene diisocyanate, polyol-modified hydrogenated xylylene diisocyanate, trimmer-type hydrogenated xylylene diisocyanate, polyol-modified isophorone diisocyanate and the like are included. The exemplified polyisocyanate compound is particularly preferable because the reaction with the hydroxyl group proceeds rapidly by using the acid and the base contained in the polymer as a catalyst, which contributes to the speed of cross-linking.

As the peroxide, any peroxide that generates radically active species by heating or light irradiation to promote cross-linking of the base polymer of the pressure-sensitive adhesive composition can be appropriately used, but in consideration of workability and stability. It is preferable to use a peroxide having a half-life temperature of 80 ° C. to 160 ° C. for 1 minute, and more preferably to use a peroxide having a half-life temperature of 90 ° C. to 140 ° C.

Examples of the peroxide include di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.) and di-sec-butylperoxydicarbonate (1 minute half-life temperature). : 92.4 ° C.), t-butylperoxyneodecanoate (1 minute half-life temperature: 103.5 ° C.), t-hexylperoxypivalate (1 minute half-life temperature: 109.1 ° C.), t -Butyl peroxypivalate (1 minute half temperature: 110.3 ° C), dilauroyl peroxide (1 minute half temperature: 116.4 ° C), di-n-octanoyl peroxide (1 minute half temperature) 117.4 ° C.), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1) Minute half-life temperature: 128.2 ° C), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C), t-butylperoxyisobutyrate (1 minute half-life temperature: 136.1 ° C), 1 , 1-di (t-hexyl peroxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) and the like. Among them, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.) and dilauroyl peroxide (1 minute half-life temperature: 116.) Since the cross-linking reaction efficiency is particularly excellent. 4 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C.) and the like are preferably used.

The half-life of the peroxide is an index showing the decomposition rate of the peroxide, and means the time until the residual amount of the peroxide is halved. The decomposition temperature for obtaining a half-life at an arbitrary temperature and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc. For example, "Organic Peroxide Catalog 9th Edition" of Nippon Oil & Fats Co., Ltd. (May 2003) ”and so on.

The amount of the cross-linking agent used is preferably 20 parts by weight or less, more preferably 0.01 to 20 parts by weight, based on 100 parts by weight of the base polymer such as the (meth) acrylic polymer in the pressure-sensitive adhesive composition. Further, 0.03 to 10 parts by weight is preferable. If the amount of the cross-linking agent is more than 20 parts by weight, the moisture resistance is not sufficient and peeling is likely to occur in a reliability test or the like.

Further, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer having the dye of the present invention may contain a silane coupling agent. Durability can be improved by using a silane coupling agent. Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,). 4-Epoxycyclohexyl) Epyl group-containing silane coupling agents such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N- (1,3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltri Examples thereof include a (meth) acrylic group-containing silane coupling agent such as ethoxysilane, and an isocyanate group-containing silane coupling agent such as 3-isoxapropyltriethoxysilane.

The silane coupling agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the base polymer such as the (meth) acrylic polymer. On the other hand, 0.001 to 5 parts by weight of the silane coupling agent is preferable, 0.01 to 1 part by weight is more preferable, 0.02 to 1 part by weight is more preferable, and 0.05 to 0 part is more preferable. 6.6 parts by weight is preferable. It is an amount that improves durability and appropriately retains adhesive force to optical members such as liquid crystal cells.

Further, in the present invention, a polyether-modified silicone can be blended in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer having a dye. As the polyether-modified silicone, for example, those disclosed in JP-A-2010-275522 can be used.

Further, in the present invention, other known additives may be contained in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer having a pigment, for example, a colorant, a powder such as a pigment, a dye, and a surfactant. Agents, plasticizers, tackifiers, surfactants, leveling agents, softeners, anti-aging agents, antioxidants, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, It can be appropriately added depending on the intended use of particles, foils and the like. Further, a redox system to which a reducing agent is added may be adopted within a controllable range.

A pressure-sensitive adhesive layer having a dye is formed from the pressure-sensitive adhesive composition. In forming the pressure-sensitive adhesive layer, the amount of the cross-linking agent added is adjusted, and the influences of the cross-linking treatment temperature and the cross-linking treatment time are fully considered. Is preferable.

The cross-linking treatment temperature and the cross-linking treatment time can be adjusted depending on the cross-linking agent used. The crosslinking treatment temperature is preferably 170 ° C. or lower.

Further, the cross-linking treatment may be performed at the temperature at the time of the drying step of the pressure-sensitive adhesive layer, or may be carried out by separately providing a cross-linking treatment step after the drying step.

The crosslinking treatment time can be set in consideration of productivity and workability, but is usually about 0.2 to 20 minutes, preferably about 0.5 to 10 minutes.

As a method for forming a pressure-sensitive adhesive layer having a dye, for example, the pressure-sensitive adhesive composition is applied to a separator that has been peeled off, and a polymerization solvent or the like is dried and removed to form a pressure-sensitive adhesive layer, and then a polyvinyl alcohol-based polarizing element is formed. The pressure-sensitive adhesive composition is applied to a polarizing film having a polyvinyl alcohol-based polarizing element, and the pressure-sensitive adhesive layer is removed by drying to remove a polymerization solvent or the like. It is produced by a method of forming in. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

As the peeling-treated separator, a silicone peeling liner is preferably used. In the step of applying the adhesive composition of the present invention on such a liner and drying it to form a pressure-sensitive adhesive layer, as a method of drying the pressure-sensitive adhesive, an appropriate method is appropriately adopted according to the purpose. obtain. Preferably, a method of overheating and drying the coating film is used. The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 70 ° C. to 170 ° C. By setting the heating temperature in the above range, a pressure-sensitive adhesive having excellent adhesive properties can be obtained.

As the drying time, an appropriate time may be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Further, an anchor layer (for example, about 0.5 to 2 μm in thickness) is formed on the surface of a polarizing film having a polyvinyl alcohol-based polarizing element, and various easy-adhesion treatments such as corona treatment and plasma treatment are performed before the pressure-sensitive adhesive. Layers can be formed. Further, the surface of the pressure-sensitive adhesive layer may be subjected to an easy-adhesion treatment.

Various methods are used as the method for forming the pressure-sensitive adhesive layer. Specifically, for example, 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, etc. Examples include the extrusion coating method.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. It is preferably 2 to 50 μm, more preferably 2 to 40 μm, and even more preferably 5 to 35 μm. The thickness of the pressure-sensitive adhesive layer containing the dye is preferably 25 μm or less in order to prevent oxygen from entering from the end portion of the pressure-sensitive adhesive layer.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a sheet (separator) that has been peeled off until it is put into practical use.

<Film layer>
In addition, examples of the optical functional layer of the present invention include a film layer containing a dye, and the film layer can be formed from a base polymer for film formation and a composition containing a dye. As the material of the base polymer forming the film layer, the same materials as those constituting the transparent protective film described later can be exemplified. In particular, as the material, a cellulose resin such as triacetyl cellulose, a polyester resin, a (meth) acrylic resin, a cyclic polyolefin resin (norbornen-based resin) and the like are preferably used. The film layer can be applied to a polyvinyl alcohol-based polarizing element by appropriately using an adhesive, an adhesive, or the like.

As a method for forming the film layer containing the dye, various methods can be adopted. For example, when the pellet of the resin material is dissolved in a solvent, a dye is mixed to prepare a composition, and the composition can be cast or extruded to produce a film layer. At that time, the film layer can be formed to an appropriate thickness. Additives can be added as appropriate when preparing the composition.

The thickness of the film layer is not particularly limited and is the same as that of the pressure-sensitive adhesive layer, for example, about 1 to 100 μm. It is preferably 2 to 50 μm, more preferably 2 to 40 μm, and even more preferably 5 to 35 μm. The separator can also be applied to a film layer containing a dye.

Examples of the constituent material of the separator include plastic 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. An appropriate thin-leaved body or the like can be mentioned, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the optical functional layer (particularly, the pressure-sensitive adhesive layer), and is, for example, a polyvinyl alcohol film, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, and a polymethyl. Examples thereof include a penten film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. The separator 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, a kneading type, and a vapor deposition type. It is also possible to perform antistatic treatment such as. 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 separator, the peelability from the optical functional layer (particularly, the pressure-sensitive adhesive layer) can be further enhanced.

The peeled sheet used for producing the above-mentioned polarizing film with an adhesive layer can be used as it is as a separator for the polarizing film with an optical functional layer, and can be simplified in terms of process.

As the separator, the oxygen permeability of ^{1 [cm 3 / (m 2} · 24h · atm)] is preferably used the following ones. The oxygen permeability ^is 0.8 preferably ^{[cm 3 / (m 2 ·} 24h · atm)] or less, more preferably ^{0.6 [cm 3 / (m 2} · 24h · atm)] or less, more ^{0.5 [cm 3 / (m 2} · 24h · atm)] or less. The oxygen permeability is determined by the material, thickness and the like. Specifically, the oxygen permeability of the optical member is measured according to the description of the embodiment.

As the separator capable of satisfying the low oxygen permeability, for example, polyvinyl alcohol film, polyethylene terephthalate film, aluminum-deposited film, polyacrylonitrile, ethylene vinyl alcohol and the like are preferable. The thickness of the film is preferably 10 to 100 μm, more preferably 25 to 75 μm.

<Polarizing film>
The polarizing film of the present invention has the polyvinyl alcohol-based polarizing element. The polyvinyl alcohol-based polarizer, the oxygen permeability is low, the oxygen permeability can satisfy the following ^{1 [cm 3 / (m 2} · 24h · atm)].

As the polarizing film, a polyvinyl alcohol-based polarizing element having a transparent protective film on one side or both sides is generally used.

The polyvinyl alcohol-based 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 80 μm or less.

A polarizing element obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by immersing the polyvinyl alcohol-based film in an aqueous solution of iodine to dye it and stretching it to 3 to 7 times the original length. can. 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, as the polarizing element, a thin polarizing element having a thickness of 10 μm or less can 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 JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, PCT / JP2010 / 00146, or Japanese Patent Application No. 2010-. The thin polarizing film described in the specification of No. 269002 and the specification of Japanese Patent Application No. 2010-263692 can be mentioned. 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 can improve the polarization performance even in a manufacturing method including a step of stretching in a laminated state and a step of dyeing. It is preferably obtained by a production method including a step of stretching in a boric acid aqueous solution as described in JP2010 / 00460, or in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692, particularly preferably. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in the boric acid aqueous solution described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692.

As a material constituting the transparent protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, and cyclic resins. Examples thereof include a polyolefin resin (norbornen-based resin), a polyarylate resin, a polystyrene resin, a polyvinyl alcohol resin, and a mixture thereof. A transparent protective film is attached to one side of the polarizing element by an adhesive layer, but the other side has (meth) acrylic, urethane, acrylic urethane, epoxy, and silicone as transparent protective films. A thermosetting resin such as a system or an ultraviolet curable resin can be used. The transparent protective film may contain one or more suitable additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a color inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant and the like. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. .. When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

The thickness of the transparent protective film is not particularly limited, and is, for example, about 10 to 90 μm. It is preferably 15 to 60 μm, more preferably 20 to 50 μm. When a transparent protective film is placed between the polyvinyl alcohol-based polarizing element and the pressure-sensitive adhesive layer containing the dye, the thickness adjusted so that the total thickness of the adhesive layer and the like is 45 μm or less. Transparent protective film is used.

A functional layer (surface layer) such as a hard coat layer, an antireflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the transparent protective film to which the polarizing element is not adhered.

The adhesive used for bonding the polarizing element and the transparent protective film is not particularly limited as long as it is optically transparent, and various forms such as water-based, solvent-based, hot-melt-based, radical-curing type, and cation-curing type are used. However, water-based adhesives or radically curable adhesives are suitable. The thickness of the adhesive layer is usually about 0.01 to 3 μm, preferably 0.3 to 2 μm, and more preferably 0.5 to 1.5 μm.

Examples of the layer having no dye (for example, layer B in the embodiment of FIG. 3) that can be provided between the polyvinyl alcohol-based polarizing element and the pressure-sensitive adhesive layer having the dye include the anchor layer and the polarizing element. Applicable transparent protective film, adhesive layer (to attach the transparent protective film to the polarizing element), adhesive layer (without dye), retardation layer (or retardation film), light scattering layer, light emitting layer , Undercoat layer, liquid crystal layer, polarizing layer and the like. The layer B can be used as a single layer, or a plurality of layers can be combined. When a plurality of layers (for example, layer B1 and layer B2) are used, for example, the polarizing element P / layer B1 / adhesive layer (without dye) / layer B2 / adhesive layer A (dye). It is possible to use a layer in which a plurality of layers B are laminated via a pressure-sensitive adhesive layer having no dye. The thickness of the layer B can be designed according to the characteristics of each layer in the range of 45 μm or less. The layer B also preferably has low oxygen permeability.

<LCD panel>
The polarizing film with an optical functional layer of the present invention can be suitably used when forming a liquid crystal panel. For example, in the case of a polarizing film with an adhesive layer in which the optical functional layer of the polarizing film with an optical functional layer of the present invention is an adhesive layer, the polarizing film with an adhesive layer is at least one of liquid crystal cells. A liquid crystal panel is formed by being bonded to the surface via the pressure-sensitive adhesive layer of the polarizing film with the pressure-sensitive adhesive layer. The polarizing film with an adhesive layer of the present invention is suitably used on the visible side of a liquid crystal cell.

As the liquid crystal cell, for example, any type such as TN type, STN type, π type, VA type, IPS type and the like can be used, but the liquid crystal cell of the IPS mode is preferably used for the liquid crystal panel of the present invention.

In addition to the polarizing film, another optical layer can be applied to form the liquid crystal panel. The optical layer is not particularly limited, but for example, a liquid crystal panel such as a reflector, a transflective plate, a retardation plate (including a wave plate such as 1/2 or 1/4), a viewing angle compensation film, and a brightness improving film. One or two or more optical layers that may be used for formation can be used on the visible side and / or the back side of the liquid crystal cell.

<Liquid crystal display device>
The liquid crystal panel is used as the liquid crystal display device, and is formed by appropriately assembling components such as a lighting system and incorporating a drive circuit as needed. Further, when forming the liquid crystal display device, for example, an appropriate component such as a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight is placed at an appropriate position in one layer or Two or more layers can be arranged. Further, an appropriate liquid crystal display device such as a lighting system using a backlight or a reflector can be formed.

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. All the conditions left at room temperature, which are not specified below, are 23 ° C. and 65% RH.

<Measurement of weight average molecular weight of (meth) acrylic polymer>
The weight average molecular weight (Mw) of the (meth) acrylic polymer was measured by GPC (gel permeation chromatography). Mw / Mn was also measured in the same manner.
-Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
-Column: Tosoh, G7000H _XL + GMH _XL + GMH _XL
-Column size: 7.8 mm φ x 30 cm each 90 cm in total
-Column temperature: 40 ° C
・ Flow rate: 0.8 mL / min
・ Injection amount: 100 μL
・ Eluent: Tetrahydrofuran ・ Detector: Differential refractometer (RI)
・ Standard sample: Polystyrene

<Measurement of oxygen permeability>
It was determined according to JISK 7126-2 under the conditions of 23 ° C. and 0% RH using an oxygen permeability measuring device OX-TRAN manufactured by Mocon.

Example 1
<Manufacturing of polarizing film>
In order to produce a thin polarizing layer, first, a laminate in which a 9 μm-thick PVA layer is formed on an amorphous PET substrate is subjected to aerial auxiliary stretching at a stretching temperature of 130 ° C. to form a stretched laminate, and then stretching. A colored laminate is produced by dyeing the laminate, and the colored laminate is further stretched integrally with the amorphous PET substrate by stretching in boric acid water at a stretching temperature of 65 ° C so that the total stretching ratio becomes 5.94 times. An optical film laminate containing a PVA layer having a thickness of only 4 μm was produced. The PVA molecules in the PVA layer formed on the amorphous PET substrate by such two-step stretching are highly oriented, and the iodine adsorbed by dyeing is unidirectionally oriented as a polyiodine ion complex. It was possible to generate an optical film laminate containing a PVA layer having a thickness of 4 μm, which constitutes the highly functional polarizing layer. Further, while applying a polyvinyl alcohol-based adhesive to the surface of the polarizing layer of the optical film laminate (thickness of the formed adhesive layer is 1 μm), a saponified 40 μm-thick first acrylic resin film (oxygen permeable) is further applied. degrees ^{5 [cm 3 / (m 2} · 24h · atm)]) after the combined lamination and peeling the amorphous PET substrate, thin polarizer (less oxygen permeability 0.02 ^[cm 3 / (m ² · 24h · atm)]) to produce a single protective polarizing film was used. This is called a thin single protective polarizing film.

<Preparation of (meth) acrylic polymer>
A monomer mixture containing 100 parts of butyl acrylate, 0.01 part of 2-hydroxyethyl acrylate, and 5 parts of acrylic acid was charged into a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer. Further, 0.1 part of 2,2'-azobisisobutyronitrile was charged to 100 parts of the monomer mixture together with 100 parts of ethyl acetate as a polymerization initiator, and nitrogen gas was introduced with gentle stirring to introduce nitrogen. After the substitution, the liquid temperature in the flask was maintained at around 55 ° C. and the polymerization reaction was carried out for 8 hours to obtain a solution (solid content concentration) of an acrylic polymer having a weight average molecular weight (Mw) of 1.8 million and Mw / Mn = 4.1. 30% by weight) was prepared.

(Preparation of adhesive composition)
For 100 parts of the solid content of the acrylic polymer solution produced above,
0.3 copies of benzoyl peroxide (trade name: NOF BMT manufactured by NOF CORPORATION),
1 copy of isocyanate-based cross-linking agent (trade name Coronate L manufactured by Tosoh Corporation),
A pressure-sensitive adhesive composition was obtained by blending 0.25 parts of a tetraazaporphyrin-based dye (trade name PD-320 manufactured by Yamamoto Chemicals, Inc.: having a maximum absorption wavelength at a wavelength of 595 nm) and.

(Preparation of polarizing film with adhesive layer)
The pressure-sensitive adhesive composition was evenly applied directly to the surface of the polarizing element (PVA layer) of the thin single-protective polarizing film with an applicator, and dried in an air-circulating constant temperature oven at 155 ° C. for 2 minutes. A pressure-sensitive adhesive layer having a dye with a thickness of 20 μm was formed on the surface of the polarizing element to prepare a piece-protected polarizing film with a pressure-sensitive adhesive layer.

Example 2
In Example 1, the same as in Example 1 except that the pressure-sensitive adhesive layer having a thickness of 20 μm and having no dye was laminated on the surface of the polarizing element and then the pressure-sensitive adhesive layer having a thickness of 20 μm was formed. A piece protective polarizing film with an adhesive layer was prepared.
For the formation of the pressure-sensitive adhesive layer having a thickness of 20 μm without the dye, the same pressure-sensitive adhesive composition is used except that the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer having the above-mentioned dye does not contain the dye. I used a thing. The pressure-sensitive adhesive layer is formed by uniformly applying the pressure-sensitive adhesive composition to the surface of a peeling base material (MRF38CK manufactured by Mitsubishi Plastics Co., Ltd.) of a polyethylene terephthalate film treated with a silicone-based release agent with an applicator at 155 ° C. This was performed by drying in an air circulation type constant temperature oven for 2 minutes, and the pressure-sensitive adhesive layer was transferred to the polarizing element and laminated.

Example 3
In Example 1, a pressure-sensitive adhesive having a thickness of 20 μm after laminating two layers of the pressure-sensitive adhesive layer having a thickness of 20 μm used in Example 2 on the surface of the polarizing element (total thickness of 40 μm). A piece protective polarizing film with an adhesive layer was produced in the same manner as in Example 1 except that a layer was formed. The formation of the pressure-sensitive adhesive layer having no dye is the same as that described in Example 2.

Example 4
<Manufacturing of polarizing film>
The surface of the polarizer (PVA layer) of the obtained thin piece protective polarizing film in Example 1, the second acrylic resin film of 40μm thickness was saponified (oxygen permeability ^{5 [cm 3 / (m 2} · 24h · Atm)]) was bonded via an adhesive (thickness of the adhesive layer 1 μm) to prepare both protective polarizing films. This is called a thin double protective polarizing film.

(Preparation of polarizing film with adhesive layer)
The pressure-sensitive adhesive composition used in Example 1 was directly and evenly applied to the back surface (opposite to the adhesive layer) of the second acrylic resin film of both protective polarizing films with an applicator at 155 ° C. The film was dried in an air circulation type constant temperature oven for 2 minutes to form a pressure-sensitive adhesive layer having a dye with a thickness of 20 μm on the back surface of the second acrylic resin film to prepare a piece-protected polarizing film with a pressure-sensitive adhesive layer.

Comparative Example 1
In Example 1, a pressure-sensitive adhesive having a thickness of 20 μm after laminating three layers of the pressure-sensitive adhesive layer having a thickness of 20 μm used in Example 2 on the surface of the polarizing element (total thickness of 60 μm). A piece protective polarizing film with an adhesive layer was produced in the same manner as in Example 1 except that a layer was formed. The formation of the pressure-sensitive adhesive layer having no dye is the same as that described in Example 2.

Comparative Example 2
In Example 1, instead of forming the pressure-sensitive adhesive composition on the surface of the polarizing element (PVA layer) of the thin piece protective polarizing film, a saponified 40 μm-thick acrylic resin film (oxygen permeability 5 [cm ^{3)). / (m 2 · 24h · atm} )] except for forming a) to prepare an acrylic resin film with a pressure-sensitive adhesive layer in the same manner as in example 1.

The following evaluation was performed using the single-sided protective or double-protective polarizing film with an adhesive layer or the acrylic resin film with an adhesive layer obtained in the above Examples and Comparative Examples as samples. The evaluation results are shown in Table 1.

(Evaluation of fading)
After cutting the sample into test pieces having a length of 50 mm and a width of 25 mm, the state (initial) of the front surface and the end portion was captured as a photograph using a scanner (specifically, Canon's trade name PIXMA MX923). Then, after performing a durability test in which the sample is left in a constant temperature bath at 85 ° C. for 24 hours, it is taken out, returned to room temperature (23 ° C.), and then again in the state of the front and end of the sample (after 24 hours). Was captured again as a photograph using a similar scanner. The photographs before (initial) and after (24) hours after the test injection were binarized, and the presence or absence of color loss on the front surface and the amount of color loss at the edges were measured by the following method.

<Color loss on the front>
Based on the images of the binarized photograph before the test piece was put into the durability test and the binarized photograph after the put-in, it was visually evaluated whether or not the color was missing. Table 1 also shows the transmittance before and after putting the test piece into the durability test. The transmittance was measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c of Murakami Color Technology Laboratory) with the test piece at 23 ° C.
〇 There is no color difference compared to before the introduction.
× The color is clearly lighter than before it was added.

<Color loss at the edges>
From the peripheral edge of the test piece toward the center, measure the distance of the longest part of the peripheral edge where the color is clearly missing with a ruler, and evaluate this as the color loss (fading progress distance: mm). did.

In the examples, there was no color loss on the front surface, and the amount of color loss on the edges was small. The color loss (fading progress distance: mm) at the end is preferably 3 mm or less, more preferably 2 mm or less, further preferably 1 mm or less, and preferably 0 mm. On the other hand, in Comparative Example 1, since the polyvinyl alcohol-based polarizing element was used, no color loss was observed in the front surface, but the distance between the polyvinyl alcohol-based polarizing element and the optical functional layer (adhesive layer) was large. It was possible to exceed 45 μm, and color loss (fading traveling distance: mm) at the end was observed. In Comparative Example 2, since the polyvinyl alcohol-based polarizing element was not used, both front color loss and edge color loss were observed.

P Polyvinyl alcohol-based polarizing element A Optical functional layer F Transparent protective film S Separator B, C Other layers x Distance from the adhesive layer with the polyvinyl alcohol-based polarizing element

Claims (1)

A polarizing film with an optical functional layer having an optical functional layer containing a dye on at least one side of a polarizing film having a polyvinyl alcohol-based polarizing element, wherein the polyvinyl alcohol-based polarizing element and the optical functional layer containing the dye are used. A polarizing film with an optical functional layer, characterized in that the distance is 45 μm or less.

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