JP2018025790A - Laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film capable of maintaining a high degree of polarization even in humid and hot environments.SOLUTION: A laminated film includes: a polarizer layer in which a dichroic dye is oriented in a polyvinyl alcohol-based resin; a resin layer that has a resin film, as a formation material, having a slow axis in direction oblique to an absorption axis of the polarizer layer; and an adhesive layer for adhering between the polarizer layer and the resin layer. The resin layer contains a plasticizer. The adhesive layer contains, as a formation material, a hardened product of an adhesive composition containing an oxetane compound. The oxetane compound has a main chain having an ether linkage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated film.

  Conventionally, a polarizing plate has been widely used as a polarized light supplying element and a polarized light detecting element in a display device such as a liquid crystal display device. A polarizing plate having a configuration in which a protective film is bonded to one side or both sides of a polarizing film (polarizer layer) using an adhesive or the like is known.

  As a polarizing film, a film in which a dichroic dye such as iodine is oriented on a film made of a polyvinyl alcohol resin is known. Iodine in the polarizing film exists as an iodine complex, and the iodine complex itself is oriented depending on the orientation of the polyvinyl alcohol resin. It is known that this iodine complex absorbs light in the visible region, so that the polarizing film exhibits polarization characteristics (polarization degree).

  By the way, when applying a polarizing plate to a display device, various optical layers (resin layers) such as a phase difference plate and an optical compensation film having optical properties are provided on a polarizing film provided with a protective film, if necessary. Is bonded (for example, Patent Document 1). The optical layer may contain an additive such as a plasticizer for the purpose of improving the performance of the film.

JP 2011-186482 A

  However, when the polarizing plate described in Patent Document 1 is left in a humid heat environment (for example, at room temperature of 60 ° C. and humidity of 95%), the degree of polarization may decrease.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the laminated | multilayer film which can maintain a high degree of polarization also in a humid heat environment.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have transferred the plasticizer contained in the optical layer to the polarizing film in a humid heat environment and reacted with the iodine complex contributing to the polarization. It was estimated that the degree of polarization of the resulting polarizing plate was reduced by the disappearance of the iodine complex. On the other hand, by applying a cured product of an adhesive composition containing an oxetane compound as a material for forming an adhesive layer interposed between the polarizing film and the optical layer, the migration of the plasticizer to the polarizing film can be suppressed. Thus, the present invention has been completed.

  One embodiment of the present invention is a material for forming a polarizer film in which a dichroic dye is oriented in a polyvinyl alcohol resin, and a resin film having a slow axis in a direction oblique to the absorption axis of the polarizer layer And a cured product of an adhesive composition that includes a plasticizer, and the adhesive layer includes an oxetane compound. And the oxetane compound provides a laminated film having an ether bond in the main chain.

  In one embodiment of the present invention, the oxetane compound preferably includes a plurality of oxetane rings.

  In one embodiment of the present invention, the polarizer layer and the resin layer may both be long.

  According to one embodiment of the present invention, there is provided a laminated film that can maintain a high degree of polarization even in a humid heat environment.

It is a cross-sectional schematic diagram which shows an example of the laminated constitution of the laminated film of this embodiment. It is a cross-sectional schematic diagram which shows the modification of the layer structure of the laminated | multilayer film of this embodiment.

<Laminated film>
FIG. 1 is a schematic cross-sectional view showing an example of the layer configuration of the laminated film of the present embodiment. As shown in FIG. 1, the laminated film 1 of this embodiment includes a polarizer layer 11, a resin layer 21, and an adhesive layer 31 that bonds the polarizer layer 11 and the resin layer 21. In another embodiment, a protective film may be further laminated on the side of the polarizer layer 11 opposite to the resin layer 21.

  The laminated film of the present embodiment may be long or may be a single wafer obtained by cutting the long laminated film into a predetermined length. The long laminated film includes a long polarizer layer and a long resin layer. The long polarizer layer and the long resin layer will be described later.

[Polarizer layer]
A polarizer layer refers to an optical film having the property of absorbing linearly polarized light having a vibration plane parallel to the optical axis and transmitting linearly polarized light having a vibration plane perpendicular to the optical axis. Specifically, the polarizer layer 11 of this embodiment is a film in which a dichroic dye is oriented in a polyvinyl alcohol-based resin (hereinafter sometimes referred to as “PVA-based resin”).

  The thickness of the polarizer layer 11 is preferably 30 μm or less, more preferably 25 μm or less, further preferably 15 μm or less, particularly preferably 10 μm or less, and particularly preferably 7 μm or less. preferable.

  When the polarizer layer 11 is a film in which a dichroic dye is oriented in a PVA-based resin, the polarizer layer 11 may be obtained by stretching a film original including the PVA-based resin. When the thickness of the polarizer layer 11 is 7 μm or less, the polarizer layer 11 may be obtained by stretching a coating film containing a PVA-based resin formed on the substrate together with the substrate, and then peeling the substrate.

  Examples of the substrate that may be used in the present embodiment include a polypropylene film, a polyethylene terephthalate film, a polycarbonate film, a triacetyl cellulose film, a norbornene film, a polyester film, and a polystyrene film.

  Examples of the PVA resin used in the present embodiment include a saponified polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having ammonium groups.

  The saponification degree of the PVA resin is preferably 80 mol% or more, more preferably 90 mol% or more and 99.5 mol% or less, and further preferably 94 mol% or more and 99 mol% or less. . When the degree of saponification is 80 mol% or more, the moisture and heat resistance of the resulting laminated film 1 is improved. Moreover, the laminated | multilayer film 1 which has sufficient polarization | polarized-light performance as saponification degree is 99.5 mol% or less is obtained.

  The PVA resin may be a modified polyvinyl alcohol partially modified. For example, olefin modification with ethylene, propylene, etc .; unsaturated carboxylic acid modification with acrylic acid, methacrylic acid, crotonic acid, etc .; one modified with an alkyl ester of unsaturated carboxylic acid, acrylamide or the like may be used.

  The modification ratio of the PVA resin is preferably less than 30 mol%, and more preferably less than 10%. When a PVA resin having a modification ratio of less than 30 mol% is used, the dichroic dye can be sufficiently adsorbed, and a polarizer having sufficient polarization performance can be obtained.

  The average degree of polymerization of the PVA resin is preferably 100 or more and 10,000 or less, more preferably 1500 or more and 8000 or less, and further preferably 2000 or more and 5000 or less. When the average degree of polymerization is 100 or more, a polarizer having sufficient polarization performance can be obtained. Moreover, when the average degree of polymerization is 10,000 or less, the solubility in a solvent becomes good, and the formation of a film containing a PVA resin is easy.

  Commercially available PVA-based resins can be easily obtained, and preferable examples of commercially available products are trade names, “PVA124” and “PVA117” (both saponification degrees) manufactured by Kuraray Co., Ltd. : 98-99 mol%), "PVA624" (degree of saponification: 95-96 mol%), "PVA617" (degree of saponification: 94.5-95.5 mol%); manufactured by Nippon Synthetic Chemical Industry Co., Ltd. "N-300" and "NH-18" (both saponification degree: 98-99 mol%), "AH-22" (saponification degree: 97.5-98.5 mol%), "AH-26 “(Saponification degree: 97 to 98.8 mol%)” “JC-33” (saponification degree: 99 mol% or more), “JF-17”, “JF-17L” of Nippon Vinegar Poval Co., Ltd. And "JF-20" (both saponification degree: 98-99 mol) ), “JM-26” (degree of saponification: 95.5 to 97.5 mol%), “JM-33” (degree of saponification: 93.5 to 95.5 mol%), “JP-45” ( Saponification degree: 86.5 to 89.5 mol%).

  Examples of the dichroic dye used in the present embodiment include iodine or a dichroic organic dye. Dichroic organic dyes include Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B , Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Spura Blue G, Spura Blue GL, Spura Orange GL, Direct Sky Blue , Direct First Orange S, and First Black.

  A dichroic dye may be used individually by 1 type, and may use 2 or more types together.

[Resin layer]
The resin layer 21 of the present embodiment uses a resin film having a slow axis in a direction oblique to the absorption axis of the polarizer layer 11 as a forming material. Such a resin film can be manufactured through a stretching process, and the resin film is left with a tensile stress in a direction oblique to the absorption axis of the polarizer layer 11. This residual stress can also cause a decrease in the degree of polarization of the laminated film in a moist heat environment, similarly to the migration of the plasticizer described later.

  The resin layer 21 has a slow axis in a direction oblique to the absorption axis of the polarizer layer 11. For example, the angle of the slow axis is 45 ± 10 ° or 135 with respect to the absorption axis of the polarizer layer 11. It is preferably ± 10 °. When the angle of the slow axis is in the above range, the difference between the light phase in the fast axis direction and the light phase in the slow axis direction is π / 2. When the phase difference between the fast axis and the slow axis is π / 2, when the laminated film 1 of the present embodiment is applied to a display device, the light that has passed through the laminated film 1 can be made into circularly polarized light. . Therefore, even when viewed through a polarizing glass, a configuration with excellent visibility can be obtained.

  The resin layer 21 of this embodiment is preferably a retardation layer having retardation characteristics and wavelength dispersion characteristics that satisfy the following formulas (1) to (4). When the resin layer 21 satisfies the formulas (1) to (4), when the laminated film 1 of the present embodiment is incorporated in a display device, the screen is viewed from various directions (azimuth and polar angles) through the polarizing glass. It is possible to effectively suppress the color change when viewing the screen. Thereby, the visibility of the image display device can be improved.

(1) 100 nm ≦ R _e (590) ≦ 180 nm,
(2) 0.5 <R _th (590) / R _e (590) ≦ 0.8,
(3) 0.85 ≦ R _e (450) / R _e (550) <1.00, and (4) 1.00 <R _e (630) / R _e (550) ≦ 1.1

In the formula, R _e (590), R _e (450), R _e (550), and R _e (630) represent in-plane retardation values at measurement wavelengths of 590 nm, 450 nm, 550 nm, and 630 nm, respectively, and R _th ( 590) represents a thickness direction retardation value at a measurement wavelength of 590 nm. These in-plane retardation value and thickness direction retardation value are values measured in an environment of a temperature of 23 ° C. and a humidity of 55% RH.

Plane retardation value R _e, and the thickness direction retardation value R _th, refraction of the refractive index in the in-plane slow axis direction n _x, plane fast axis direction (perpendicular to the plane slow axis direction) When the rate is _ny , the refractive index in the thickness direction is _nz , and the thickness of the optical film is d, it is defined by the following formulas (S1) and (S2).

_{(S1) R e = (n} x -n y) × d
_{(S2) R th = [{} (n x + n y) / 2} -n z] × d

From the viewpoint of more effectively suppressing the color change in the laminated film 1, R _e (590) in the formula (1) is preferably 105 to 170 nm. R _th (590) / R _e (590) in the formula (2) is preferably 0.6 to 0.75. In the formula (3), R _e (450) / R _e (550) is preferably 0.86 to 0.98. In the formula (4), R _e (630) / R _e (550) is preferably 1.01 to 1.06.

  For example, the resin layer 21 can be produced by stretching a film containing a resin described later. Examples of the stretching treatment include uniaxial stretching and biaxial stretching.

  Examples of the stretching direction include a machine flow direction (MD) of an unstretched film, a direction orthogonal to the machine flow direction (TD), and a direction oblique to the machine flow direction (MD). Here, the unstretched film refers to a film that is not stretched. In uniaxial stretching, an unstretched film is stretched in any one of these directions. On the other hand, the biaxial stretching may be simultaneous biaxial stretching that simultaneously stretches in two stretching directions, or may be sequential biaxial stretching that stretches in another direction after stretching in a predetermined direction.

  For the stretching process, for example, two or more pairs of nip rolls with increased peripheral speed on the outlet side are used to stretch in the longitudinal direction (machine flow direction: MD), or the both ends of the unstretched film are gripped with a chuck and machine flow is performed. It can be performed by spreading in a direction (TD) orthogonal to the direction. At this time, the retardation value and the wavelength dispersion can be controlled within the ranges of the above formulas (1) to (4) by adjusting the thickness of the film or adjusting the draw ratio.

  Moreover, it is possible to control the wavelength dispersion value within the range of the above formulas (3) to (4) by adding a wavelength dispersion adjusting agent to the resin.

  In general, a long polarizing film (polarizer layer) has an absorption axis in the long side direction. The long resin layer and the long polarizer layer can be bonded by roll-to-roll, and the angle between the absorption axis and the slow axis of the resin layer is within the above range. It is preferable that the resin layer 21 is manufactured by being obliquely stretched by biaxial stretching.

  Examples of the resin forming the resin film include cellulose acetate resin, cycloolefin resin, polyolefin resin, acrylic resin, polyimide resin, polycarbonate resin, and polyester resin.

  The cellulose acetate-based resin is composed of a cellulose portion or a complete acetate ester. Examples of the cellulose acetate resin include triacetyl cellulose and diacetyl cellulose.

  A resin film made of a cellulose acetate resin can be easily obtained as a commercial product. As a preferable example of the commercial product, all of them are trade names of “Fujitac (registered)” sold by FUJIFILM Corporation. Trademark) TD80 "," Fujitac (registered trademark) TD80UF "and" Fujitac (registered trademark) TD80UZ "," KC8UX2M "and" KC8UY "sold by Konica Minolta Opto Corporation.

  The cycloolefin resin forming the resin film is, for example, a thermoplastic amorphous resin having a monomer unit composed of a cyclic olefin (cycloolefin) such as norbornene or a polycyclic norbornene monomer (non-crystalline polyolefin). Also called resin.) The cycloolefin-based resin may be a hydrogenated product of the above-mentioned cycloolefin ring-opening polymer or a hydrogenated product of a ring-opening copolymer using two or more kinds of cycloolefins. It may be an addition copolymer with an olefin and / or an aromatic compound having a vinyl group. In addition, a polar group may be introduced.

  When a resin film is formed using a copolymer of a cycloolefin and a chain olefin and / or an aromatic compound having a vinyl group, examples of the chain olefin include ethylene and propylene. Examples of the aromatic compound having a vinyl group include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. In such a copolymer, the unit of the monomer composed of cycloolefin may be 50 mol% or less, and preferably 15 to 50 mol%.

  In particular, when a terpolymer of a cycloolefin, a chain olefin, and an aromatic compound having a vinyl group is used, the amount of the monomer unit comprising the cycloolefin can be made relatively small as described above. In such a terpolymer, the monomer unit composed of a chain olefin is preferably 5 to 80 mol%. Moreover, it is preferable that the unit of the monomer which consists of an aromatic compound which has a vinyl group is 5-80 mol%.

  Cycloolefin-based resins can be easily obtained from commercial products, and preferable examples of the commercial products are all trade names, manufactured by TOPAS ADVANCED POLYMERS GmbH, sold in Japan by Polyplastics Co., Ltd. "TOPAS (registered trademark)", "Arton (registered trademark)" sold by JSR Corporation, "ZEONOR (registered trademark)" and "ZEONEX" sold by Nippon Zeon Corporation. ) (Registered trademark) ”,“ Apel (registered trademark) ”sold by Mitsui Chemicals, Inc., and the like.

  When the resin layer 21 of the present embodiment is a retardation layer, the thickness of the retardation layer is preferably 10 μm or more and 50 μm or less.

  In addition to the resin that forms the resin film, the resin layer 21 of the present embodiment includes a plasticizer for the purpose of imparting flexibility to the resin film and facilitating stretching. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane.

  Only one type of plasticizer may be used, or two or more types may be used in combination. In particular, ethylene glycol and glycerin are preferably used.

[Adhesive layer]
The adhesive layer 31 of the present embodiment includes a cured product of an adhesive composition containing an oxetane compound (hereinafter sometimes referred to as “the present composition”) as a forming material. The oxetane compound is one of cationically polymerizable compounds and can be cured by irradiation with active energy rays (for example, ultraviolet rays, visible light, electron beams, X-rays, etc.).

  The thickness of the adhesive layer 31 is preferably 0.01 μm or more and 5 μm or less, more preferably 0.01 μm or more and 2 μm or less, and further preferably 0.01 μm or more and 1 μm or less. Sufficient adhesiveness can be acquired as the thickness of the adhesive bond layer 31 is 0.01 micrometer or more. Moreover, when the thickness of the adhesive layer 31 is 5 μm or less, the laminated film 1 is unlikely to have a poor appearance.

The moisture permeability of the adhesive layer 31 is preferably 300 g / (m ² · 24 h) or less in an evaluation sample described later. Although the lower limit of the water vapor transmission rate of the adhesive bond layer 31 is not specifically limited, For example, it is 50 g / (m < ² > 24h) and may be 100 g / (m < ² > 24h). By using the adhesive layer 31 having such moisture permeability, the width of decrease in the degree of polarization of the laminated film 1 can be further reduced.

  The evaluation sample can be produced as follows.

  First, the adhesive composition of this embodiment is apply | coated on a triacetyl cellulose film, the layer which consists of 2-3 micrometers in thickness adhesive composition is formed, and a laminated body is obtained.

Next, the obtained laminate is irradiated with ultraviolet rays from the layer side made of the adhesive composition so that the integrated light amount becomes 400 mJ / cm ² to cure the layer made of the adhesive composition. In this way, an evaluation sample is obtained. The moisture permeability of the obtained evaluation sample is measured at a temperature of 40 ° C. and a humidity of 90% RH in accordance with JIS Z 0208: 1976 “Moisture permeability test method for moisture-proof packaging material (cup method)”.

The triacetyl cellulose film used has a thickness of 57.5 μm. Moreover, the water vapor transmission rate of the triacetylcellulose film calculated | required similarly to the above is 553 g / (m < ² > * 24h).

(Oxetane compound)
The oxetane compound used in the present embodiment has an ether bond in the main chain. Furthermore, the oxetane compound preferably contains a plurality of oxetane rings in the molecule. In this specification, the main chain is the longest carbon chain when the oxetane compound is represented by a structural formula.

  Specifically, as the oxetane compound, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3 -Oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and the like. Among these, those containing a plurality of oxetane rings in the molecule are 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, di [(3-ethyl-3-oxetanyl) methyl]. Ether.

  These oxetane compounds can be easily obtained as commercial products. As commercial products, all of them are trade names sold by Toagosei Co., Ltd., “Aron Oxetane (registered trademark) OXT-121”. "Aron oxetane (registered trademark) OXT-211", "Aron oxetane (registered trademark) OXT-221", "Aron oxetane (registered trademark) OXT-212", and the like.

  The oxetane compound has a low affinity with the plasticizer and forms a crosslinked structure when polymerized. Therefore, the cured product of the composition containing the oxetane compound is considered to be difficult for the plasticizer to enter. Thereby, in the case where the plasticizer is transferred from the resin layer 21 toward the polarizer layer 11 (in the direction of the arrow in FIG. 1) in a humid heat environment (for example, an environment having a room temperature of 60 ° C. and a humidity of 95%). It is speculated that the penetration of the plasticizer can be suppressed.

  The content of the oxetane compound is preferably 10% by mass to 99% by mass and more preferably 40% by mass to 99% by mass with respect to the total amount of the present composition. When the content of the oxetane compound is within this range, a cured product having excellent crosslinking density can be obtained, and migration of the plasticizer can be suppressed.

  In this composition, an oxetane compound may be used individually by 1 type, and may use 2 or more types together.

(Other ingredients)
(Epoxy compound)
Moreover, in addition to said oxetane compound, this composition may contain an epoxy compound as needed. The epoxy compound is one of cationically polymerizable compounds like the oxetane compound, and can be cured by irradiation with active energy rays. When this composition contains an epoxy compound, the adhesiveness of the resin layer 21 and the polarizer layer 11 can be improved.

  Examples of the epoxy compound include an aromatic epoxy compound, a glycidyl ether of a polyol having an alicyclic ring, an aliphatic epoxy compound, and an alicyclic epoxy compound.

  Aromatic epoxy compounds include bisphenol type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F and diglycidyl ether of bisphenol S; phenol novolac epoxy resins, cresol novolac epoxy resins and hydroxybenzaldehyde phenol novolacs Examples thereof include novolak-type epoxy resins such as epoxy resins; glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and polyfunctional epoxy resins such as epoxidized polyvinylphenol.

  As the glycidyl ether of a polyol having an alicyclic ring, a nuclear hydrogenated polyhydroxy compound obtained by selectively hydrogenating an aromatic polyol under pressure in the presence of a catalyst under pressure is used as a glycidyl ether. Can be listed. Examples of aromatic polyols include bisphenol type compounds such as bisphenol A, bisphenol F, and bisphenol S; novolac type resins such as phenol novolac resin, cresol novolac resin, hydroxybenzaldehyde phenol novolac resin; tetrahydroxydiphenylmethane, tetrahydroxybenzophenone, A polyfunctional compound such as polyvinylphenol is exemplified.

Glycidyl ether can be obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic ring of these aromatic polyols with epichlorohydrin.
Among these glycidyl ethers of polyols having an alicyclic ring, hydrogenated bisphenol A diglycidyl ether is preferable.

  Examples of the aliphatic epoxy compound include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. Specifically, 1,4-butanediol diglycidyl ether; 1,6-hexanediol diglycidyl ether; glycerin triglycidyl ether; trimethylolpropane triglycidyl ether; polyethylene glycol diglycidyl ether; propylene glycol Diglycidyl ether of neopentyl glycol; by adding one or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol or glycerin The polyglycidyl ether of the polyether polyol obtained is mentioned.

Moreover, the monofunctional epoxy compound represented by following formula (I) is also mentioned as an aliphatic epoxy compound. R ¹ is an optionally branched alkyl group having 1 to 15 carbon atoms. The alkyl group preferably has 6 or more carbon atoms, more preferably 6 to 10 carbon atoms. Of these, a branched alkyl group is preferred. Examples of the monofunctional epoxy compound represented by the formula (I) include 2-ethylhexyl glycidyl ether.

  An alicyclic epoxy compound refers to a compound having at least one structure in the molecule forming an oxirane ring together with a carbon atom of the alicyclic ring. Here, “a structure in which an oxirane ring is formed together with a carbon atom of an alicyclic ring” means a structure represented by the following formula (II). N in a formula is an integer of 2-5.

A compound in which a group in a form in which one or a plurality of hydrogen atoms in (CH ₂ ) _n in formula (II) are removed is bonded to another chemical structure is an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _n forming the alicyclic ring may be substituted with a linear alkyl group such as a methyl group or an ethyl group.

  As the epoxy compound, an alicyclic epoxy compound is preferable, and an epoxy cyclohexane (n = 4 in the above formula (II)) or epoxy cycloheptane is preferable in that an excellent protective layer can be easily obtained due to adhesion with a polarizer. Epoxy compounds having (with n = 5 in the above formula (II)) are more preferred.

  In this composition, an epoxy compound may be used individually by 1 type, and may use 2 or more types together.

(Radically polymerizable compound)
Further, in addition to the cationically polymerizable compound such as the oxetane compound or the epoxy compound, a radical polymerizable compound may be included.

  Examples of the radical polymerizable compound include a compound having at least one (meth) acryloyloxy group in the molecule (hereinafter sometimes referred to as “(meth) acrylic compound”), and at least one ( Examples thereof include compounds having a meth) acrylamide group (hereinafter sometimes referred to as “(meth) acrylamide compounds”). The “(meth) acryloyloxy group” means a methacryloyloxy group or an acryloyloxy group, and the (meth) acrylamide group means a methacryloylamide group or an acryloylamide group.

  (Meth) acrylic compounds include (meth) acrylate monomers having at least one (meth) acryloyloxy group in the molecule and (meth) acrylates having at least two (meth) acryloyloxy groups in the molecule. An oligomer etc. are mentioned. These may be used alone or in combination of two or more. When two or more types are used in combination, two or more (meth) acrylate monomers may be used, two or more (meth) acrylate oligomers may be used, and, of course, one or more (meth) acrylate monomers. One or more (meth) acrylate oligomers may be used in combination.

Examples of (meth) acrylamide compounds include N-substituted (meth) acrylamide compounds. An N-substituted (meth) acrylamide compound is a (meth) acrylamide compound having a substituent at the N-position. A typical example of the substituent is an alkyl group. The N-position substituents may be bonded to each other to form a ring, and —CH ₂ — constituting the ring may be substituted with an oxygen atom. Further, a substituent such as an alkyl group or an oxo group (═O) may be bonded to the carbon atom constituting the ring. N-substituted (meth) acrylamides can generally be prepared by reaction of (meth) acrylic acid or its chloride with a primary or secondary amine.

  In this composition, a radically polymerizable compound may be used individually by 1 type, and may use 2 or more types together.

(Cationic polymerization initiator)
When this composition contains cationically polymerizable compounds, such as the said oxetane compound and the said epoxy compound, it is preferable that the cationic polymerization initiator is further included. The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of the cationic polymerizable compound. Examples of the cationic polymerization initiator include aromatic diazonium salts, onium salts such as aromatic iodonium salts and aromatic sulfonium salts, and iron-arene complexes.

  Examples of the aromatic diazonium salt include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.

  Examples of the aromatic iodonium salt include diphenyliodonium tetrakis (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di (4-nonylphenyl) iodonium hexafluorophosphate, and the like.

  Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4′-bis [diphenylsulfonio] diphenyl sulfide bishexa. Fluorophosphate, 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluoroantimonate, 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bis Hexafluorophosphate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfoni O] -2-Isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfo Nio-diphenyl sulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenyl sulfide tetrakis (pentafluorophenyl) borate, and the like.

  Examples of the iron-arene complex include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) tris ( (Trifluoromethylsulfonyl) methanide and the like.

  These cationic polymerization initiators can be easily obtained from commercial products, for example, “Kayarad (registered trademark) PCI-220” and “Kayarad” sold by Nippon Kayaku Co., Ltd. under the trade names, respectively. (Registered trademark) PCI-620 "," UVI-6990 "sold by Dow Chemical Company," UVACURE (registered trademark) 1590 "sold by Daicel-Cytec Corporation, sold by ADEKA Corporation "Adekaoptomer (registered trademark) SP-150" and "Adekaoptomer (registered trademark) SP-170", "CI-5102", "CIT-1370", "CIT" sold by Nippon Soda Co., Ltd. -1682 "," CIP-1866S "," CIP-2048S "and" CIP-2064S " "DPI-101", "DPI-102", "DPI-103", "DPI-105", "MPI-103", "MPI-105", "BBI-101" sold by Midori Chemical Co., Ltd. "," BBI-102 "," BBI-103 "," BBI-105 "," TPS-101 "," TPS-102 "," TPS-103 "," TPS-105 "," MDS-103 ", “MDS-105”, “DTS-102” and “DTS-103”, “PI-2074” sold by Rhodia, and the like.

  Among these cationic polymerization initiators, the aromatic sulfonium salt is capable of absorbing light having a wavelength of 300 nm or more, having excellent curability, and obtaining a cured product having good mechanical strength and adhesion. preferable.

  In this composition, a cationic polymerization initiator may be used individually by 1 type, and may mix and use 2 or more types.

(Radical polymerization initiator)
When this composition contains said radically polymerizable compound, it is preferable that the radical polymerization initiator is further included. Any radical polymerization initiator may be used as long as it can initiate polymerization of a radical polymerizable compound such as a (meth) acrylic compound by irradiation with active energy rays, and a known one can be used.

  Examples of the radical polymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- ( Acetophenone initiators such as methylthio) phenyl-2-morpholinopropan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone and 4,4′-diamino Benzophenone initiators such as benzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; other xanthone, fluorenone, camphorquinone, Lens aldehyde, such as anthraquinone, and the like.

  Commercially available radical polymerization initiators can be easily obtained. For example, “Irgacure (registered trademark) 184”, “Irgacure (registered trademark) 907” and “Darocur (registered trademark)” manufactured by BASF are available. Trademark) 1173 "," Lucirin (registered trademark) TPO ", and the like.

  In this composition, a radical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

(Other additives)
In addition to the above compounds, the present composition may contain a photosensitizer, a solvent, a leveling agent, an antioxidant, a light stabilizer, an ultraviolet absorber, and the like as long as the effects of the present invention are not impaired.

  Examples of the photosensitizer that may be used in this embodiment include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreductive dyes.

  Examples of the solvent that may be used in the present embodiment include aliphatic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; methanol, ethanol, propanol, isopropanol, and n- Alcohols such as butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; Halogenated hydrocarbons such as methylene and chloroform.

  As a leveling agent that may be used in the present embodiment, various compounds such as silicone-based, fluorine-based, polyether-based, acrylic acid copolymer-based, and titanate-based compounds can be used.

  Examples of the antioxidant that may be used in the present embodiment include primary antioxidants such as phenols and amines, and sulfur-based secondary antioxidants.

Examples of the light stabilizer that may be used in the present embodiment include hindered amine light stabilizers (HALS).
Examples of ultraviolet absorbers that may be used in this embodiment include benzophenone-based, benzotriazole-based, and benzoate-based compounds.

[Protective film]
FIG. 2 is a schematic cross-sectional view showing a modification of the layer configuration of the laminated film of the present embodiment. As shown in FIG. 2, in the laminated film 2, a protective film 23 can be further laminated on the side of the polarizer layer 11 opposite to the side where the resin layer 21 is laminated. As a material for forming the protective film 23, the same resin as the material for forming the resin layer 21 can be used. The material forming the resin layer 21 and the material forming the protective film 23 may be the same or different.

The protective film 23 can be laminated on the polarizer layer 11 via the adhesive layer 33.
Examples of the adhesive layer 33 include a water-based adhesive and an active energy ray-curable adhesive. Examples of the active energy ray-curable adhesive include a cationic polymerization-type active energy ray-curable adhesive and a radical polymerization-type active energy. A line curable adhesive is mentioned. An adhesive layer may be provided instead of the adhesive layer 33. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive containing an acrylic resin.

  An adhesive layer (not shown) may be provided on the side opposite to the surface of the polarizer layer 11 on which the resin layer 21 is laminated, or on the side of the protective film opposite to the surface on which the polarizer layer 11 is laminated. . By providing the pressure-sensitive adhesive layer, the laminated film 2 can be bonded to the liquid crystal cell of the display device. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive containing an acrylic resin. The laminated film of the present invention is preferably arranged on the viewing side of the liquid crystal cell.

[Production method of laminated film]
The laminated film 1 of this embodiment is
(I) forming a layer of an adhesive composition containing an oxetane compound (hereinafter sometimes referred to as “adhesive composition layer”) on one surface of the resin layer 21 having a slow axis;
(Ii) The polarizer layer 11 and the adhesive composition layer formed on the resin layer 21 in (i) above have a slow axis of 45 ± 10 ° with respect to the absorption axis of the polarizer layer 11. Or a step of obtaining a laminate in which the polarizer layer 11, the adhesive composition layer, and the resin layer 21 are laminated in this order by laminating so as to be 135 ± 10 °;
(Iii) The laminate obtained in (ii) above is irradiated with active energy rays (for example, ultraviolet rays, visible light, electron beams, X-rays, etc.), and the adhesive composition layer is cured to form an adhesive layer 31. And obtaining a process. Hereinafter, each process will be described with specific examples.

  In the step shown in (i) above, first, a resin layer 21 having a slow axis is prepared. When the polarizer layer 11 is continuously manufactured, the elongated polarizer layer may have an absorption axis in the flow direction. A laminate (laminated film) can be produced by roll-to-roll, and both can be arranged so that the angle formed by the absorption axis and the slow axis of the resin layer 21 falls within the above range. The resin layer 21 is preferably manufactured by being obliquely stretched.

  Examples of the stretching machine used for the oblique stretching include a tenter type stretching machine. The tenter type stretching machine can apply a feeding force, a pulling force or a pulling force at different speeds in the left and right directions in the horizontal direction or the vertical direction or in both directions. Examples of such a tenter-type stretching machine include a horizontal uniaxial stretching machine and a simultaneous biaxial stretching machine. Any suitable stretching machine can be used as long as the resin film can be continuously stretched obliquely. it can.

  Examples of a method for forming the adhesive composition layer on one surface of the resin layer 21 include a method in which the present composition is directly applied and dried as necessary. Further, as another method, there is a method in which the present composition is applied to a transparent substrate film, dried as necessary, and then transferred to the polarizer layer 11. In the latter case, the base film is removed before the step (ii). As the transparent base film, the same resin as described above is used. Moreover, in the transparent substrate film, the application surface of the present composition may be subjected to a peeling treatment in advance.

  As a coating method of this composition, a well-known coating method can be employ | adopted, for example, a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater etc. are mentioned.

  In the step shown in (ii) above, the polarizer layer 11 and the adhesive composition layer formed on the resin layer 21 in (i) above are bonded together, and the polarizer layer 11, the adhesive composition layer, and the resin layer 21 are bonded together. Are stacked in this order.

  In the step shown in (iii) above, the adhesive composition layer is formed by irradiating the laminate obtained in (ii) with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams. It hardens | cures and it is set as the adhesive bond layer 31, and the laminated | multilayer film 1 is obtained.

  The light source used for irradiation with active energy rays is not particularly limited, but a light source having a light emission distribution at a wavelength of 400 nm or less is used. Examples of such a light source include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp.

The irradiation intensity of the active energy ray varies depending on the adhesive composition to be cured, but it is preferable that the irradiation intensity in the wavelength region effective for activating the cationic polymerization initiator is set in the range of 10 to 2500 mW / cm ² .

Although the irradiation time of an active energy ray changes with adhesive compositions to harden | cure, it is preferable to set the integrated light quantity represented by the product of irradiation intensity | strength and irradiation time to the range of 10-2500 mJ / cm < ² >.

  In the above production example, the adhesive composition layer is formed on one surface of the resin layer 21, but may be formed on one surface of the polarizer layer 11 or on both surfaces. As shown in FIG. 2, a protective film 23 may be laminated on the side of the polarizer layer 11 opposite to the side where the resin layer 21 is bonded, and further a pressure-sensitive adhesive for bonding to a liquid crystal cell. A layer (not shown) may be provided.

  According to the laminated film having the above-described configuration, a high degree of polarization can be maintained even in a humid heat environment.

<Laminated film stock>
In the present embodiment, the polarizer layer and the resin layer may both be long. The laminated film original fabric (elongated laminated film) of the present embodiment includes a strip-shaped polarizing film original fabric (long-shaped polarizer layer), a belt-shaped resin film original fabric (long-shaped resin layer), and And an adhesive layer that bonds the polarizing film original and the resin film original.

  The polarizing film original fabric is a band-shaped film made of a PVA-based resin, and a dichroic dye is oriented in the longitudinal direction of the film. The PVA resin and the dichroic dye are the same as described above.

  The resin film original is formed by stretching a strip-shaped film having a thermoplastic resin and a plasticizer as a forming material in a direction oblique to the longitudinal direction of the film. Thereby, a roll, a toe | roll, and a roll are attained at the time of lamination | stacking with a polarizing film original fabric, and a manufacturing process can be simplified. The thermoplastic resin and the plasticizer are the same as described above.

  The resin film original is preferably a retardation film original. In the resin film original fabric, a slow axis is given at an arbitrary angle with respect to the absorption axis of the polarizing film original fabric. The arbitrary angle is preferably 45 ± 10 ° or 135 ± 10 ° with respect to the absorption axis of the polarizing film original. When the angle of the slow axis is in the above range, when the laminated film original fabric of the present embodiment is applied to a display device, a configuration with excellent visibility can be obtained even when viewed through a polarizing glass.

  The adhesive layer contains a cured product of an adhesive composition containing an oxetane compound as a forming material. The oxetane compound is the same as described above. The oxetane compound has a low affinity with the plasticizer and forms a crosslinked structure upon polymerization. Therefore, the cured product of the composition containing the oxetane compound is considered to be difficult for the plasticizer to enter. This suppresses the intrusion of the plasticizer even in the case where the plasticizer moves from the resin film original to the polarizing film original in a humid heat environment (for example, at room temperature of 60 ° C. and humidity of 95%). Presumed to be possible.

  According to the laminated film original fabric having the above-described configuration, a high degree of polarization can be maintained even in a humid heat environment.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The unstretched film used in this example refers to a film that has not been stretched.

[Evaluation of heat and humidity resistance of laminated film]
The laminated films of the examples and comparative examples were left in an environment of a temperature of 65 ° C. and a humidity of 90% RH for 250 hours, and the visibility correction polarization degrees before and after being left were compared. At that time, the absolute value (ΔPy) of the value obtained by subtracting the visibility-corrected polarization degree before leaving from the visibility-corrected polarization degree after being left is set to ○, and ΔPy is set to 0. What was larger than 3 was set as x. The visibility correction polarization degree was measured by the following method. The results are shown in Tables 2-5.

(Measurement of visibility correction polarization degree)
About the laminated | multilayer film of the Example and the comparative example, MD transmittance | permeability and TD transmittance | permeability in the wavelength range of 380 nm-780 nm were measured with the spectrophotometer with an integrating sphere (the JASCO Corporation make, "V7100"). Next, the degree of polarization at each wavelength was calculated based on the formula (T1) using the MD transmittance and the TD transmittance.
Here, “MD transmittance” indicates the transmittance when the direction of polarized light emitted from the Glan-Thompson prism is parallel to the transmission axis of the laminated film sample. The “TD transmittance” refers to the transmittance when the direction of polarized light emitted from the Glan-Thompson prism is orthogonal to the transmission axis of the laminated film sample.

(Measurement of moisture permeability of adhesive layer)
The moisture permeability of the following evaluation samples was adopted as the moisture permeability of the adhesive layers of the laminated films of Examples and Comparative Examples. The evaluation sample was produced as follows.

  First, the adhesive compositions of Examples and Comparative Examples were coated on a triacetyl cellulose film using a bar coater to form an adhesive composition layer having a thickness of 2 to 3 μm, and an evaluation laminate Got. For the triacetyl cellulose film, “KC6UA” manufactured by Konica Minolta Co., Ltd. was used.

Next, the obtained laminate for evaluation was irradiated with ultraviolet rays from the adhesive composition layer side using a D-bulb manufactured by Fusion UV Systems so that the accumulated light amount was 400 mJ / cm ^2, and adhered. The agent composition layer is cured. In this way, an evaluation sample was obtained. The moisture permeability of the obtained evaluation sample was measured at a temperature of 40 ° C. and a humidity of 90% RH in accordance with JIS Z 0208: 1976 “Moisture permeability test method for moisture-proof packaging material (cup method)”.

In addition, the thickness of the used triacetyl cellulose film was 57.5 micrometers. The moisture permeability of the triacetyl cellulose film determined in the same manner as described above was 553 g / (m ² · 24 h).

[Production Example (Preparation of Adhesive Composition)]
According to the compounding amounts shown in Tables 2 to 5, adhesive compositions of Examples and Comparative Examples were prepared. However, the names of the compounds used for the preparation may be indicated by abbreviations.
The cationic polymerization initiator “Adekaoptomer (registered trademark) SP-150” uses a propylene carbonate solution, but in Tables 2 to 5, it is indicated by the amount of the active ingredient. The epoxy-based cross-linking agent “SUMIREZ RESIN (registered trademark) 650” is an aqueous solution, but in Table 5, it is indicated by the amount of its active ingredient.

  In addition, the following compounds were used about each component of the adhesive composition.

[Active energy ray-curable adhesive composition]
(Cationically polymerizable compound)
“Celoxide (registered trademark) 2021P”: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, obtained from Daicel Chemical Industries, Ltd.
“YX8000”: Diglycidyl ether of bisphenol, obtained from Mitsubishi Chemical Corporation.
“TECHMORE® VG3101L”: 2- [4- (2,3-epoxypropoxy) phenyl] -2- [4- [1,1-bis [4-([2,3-epoxypropoxy] phenyl]] Ethyl] phenyl] propane, obtained from Printec.
“Aron Oxetane (registered trademark) OXT-101”: 3-ethyl-3-hydroxymethyloxetane, obtained from Toagosei Co., Ltd.
“Aron Oxetane (registered trademark) OXT-212”: 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, obtained from Toagosei Co., Ltd.
“Aron oxetane (registered trademark) OXT-221”: di [(3-ethyl-3-oxetanyl) methyl] ether, obtained from Toagosei Co., Ltd.

  Table 1 shows the structure of the oxetane compound.

(Radically polymerizable compound)
“A-DCP”: tricyclodecane dimethanol diacrylate, obtained from Shin-Nakamura Chemical Co., Ltd.

(Cationic polymerization initiator)
“Adekaoptomer (registered trademark) SP-150”: 4,4′-bis [diphenylsulfonio] diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator, obtained from ADEKA Corporation in the form of a propylene carbonate solution.

(Radical polymerization initiator)
“Darocur (registered trademark) 1173”: 2-hydroxy-2-methyl-1-phenyl-propan-1-one, obtained from BASF Japan Ltd.

[Water-based adhesive composition]
(Polyvinyl alcohol)
“Kuraray Poval (registered trademark) KL-318”: a carboxyl group-modified polyvinyl alcohol, obtained from Kuraray Co., Ltd.

(Epoxy-based crosslinking agent)
“Smilease Resin (registered trademark) 650”: Water-soluble polyamide epoxy resin (aqueous solution with a solid content of 30%), obtained from Sumika Chemtex Co., Ltd.

[Other ingredients]
“SH710”: Silicone leveling agent, obtained from Toray Dow Corning Co., Ltd.

[Examples 1 to 13, Comparative Examples 1 to 6]
(A) Preparation of polarizer layer A polyvinyl alcohol film having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 30 μm is uniaxially stretched about 5 times in a dry process, and further kept in a tension state After being immersed in pure water at 60 ° C. for 1 minute, it was immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the film was washed with pure water at 26 ° C. for 20 seconds, and then dried at 65 ° C. to prepare a polarizer layer in which iodine was oriented on a uniaxially stretched polyvinyl alcohol film. The thickness of the polarizer layer was 12 μm.

(B) Preparation of resin layer A triacetyl cellulose film produced by oblique stretching as a resin layer and containing a plasticizer was prepared.
A hard coat layer was formed on one side of the triacetyl cellulose film. Moreover, the angle of the slow axis with respect to the longitudinal direction of the film of the resin layer was about 45 ° on average.
The following materials were used as the triacetyl cellulose film produced by oblique stretching.
Triacetyl cellulose film produced by the oblique stretching: Konica Minolta Co., Ltd., KC4UGR-HC, thickness _{= 44μm, R e (590)} = 106nm, R th (590) = 75nm, R th (590) / R e ( 590) = 0.71, R _e (450) / R _e (550) = 0.96, R _e (630) / R _e (550) = 1.02)
_{Incidentally, R e (590), R} e (450), R e (550), R e (630) , respectively, represent the measurement wavelength 590 nm, 450 nm, 550 nm, an in-plane retardation value at 630 nm, R _th (590 ) Represents a thickness direction retardation value at a measurement wavelength of 590 nm.

(C) Production of laminated film Next, the adhesive composition obtained in the production example was applied to the surface of the resin layer (b) where the hard coat layer was not formed to form an adhesive composition layer. . Specifically, the adhesive composition was applied using a bar coater (manufactured by Daiichi Rika Co., Ltd.) so that the film thickness after curing was about 2 μm.

  Separately, a corona discharge treatment was performed on one side of an unstretched film (trade name “ZEONOR (registered trademark)” manufactured by Nippon Zeon Co., Ltd.) using a norbornene resin having a thickness of 23 μm as a forming material. The adhesive composition was applied to the corona discharge treated surface in the same manner as the resin layer to form an adhesive composition layer. The unstretched film is used as a protective film in the laminated film.

  While bonding one surface of the polarizer layer produced by said (a) and the adhesive composition layer formed in the resin layer prepared by said (b), the other surface of a polarizer layer, and an unstretched film The adhesive composition layer formed on was laminated to prepare a laminate. For pasting, a pasting apparatus (manufactured by Fuji Pla Co., Ltd., “LPA3301”) was used. When pasting, the angle formed by the absorption axis of the polarizer layer and the slow axis of the resin layer was set to 45 °.

Next, using an ultraviolet irradiation device with a belt conveyor (the lamp uses a “D bulb” manufactured by Fusion UV Systems), the accumulated light amount is 250 mJ / cm ² from the unstretched film side of the obtained laminate. The adhesive composition layer was cured by irradiating with UV rays. In this way, a laminated film composed of protective film / adhesive layer / polarizer layer / adhesive layer / resin layer / hard coat layer was produced.

The moisture permeability of the adhesive layers obtained by curing the adhesive composition layers used in the following examples and comparative examples was as follows.
Example ^{13: 293g / (m 2 ·} 24h), Comparative Example ^{1: 447g / (m 2 ·} 24h), Comparative Example ^{3: 307g / (m 2 ·} 24h), Comparative Example ^{4: 428g / (m 2 ·} 24h ), Comparative Example 5: 529 g / (m ² · 24 h).

[Comparative Example 7]
(C) A laminated film of Comparative Example 7 was produced in the same manner as in Example 1 except that the following operation was performed in the production of the laminated film.

  The resin layer prepared in (b) above was bonded to one surface of the polarizer layer prepared in (a) above via the aqueous adhesive composition obtained in the production example. Then, after drying at 80 degreeC for 5 minute (s), it cured at 40 degreeC and 23% RH for 72 hours, and produced the laminated | multilayer film.

  From the results of Tables 2 to 5, an adhesive composition containing an oxetane compound having an ether bond in the main chain ("Aron oxetane (registered trademark) OXT-212" and "Aron oxetane (registered trademark) OXT-221") was used. In this case, ΔPy was 0.3 or less, and it was shown that a high degree of polarization was maintained even in a humid heat environment.

  In the following reference examples, it was confirmed that the problem of the present invention occurs when the slow axis of the resin layer is oblique to the absorption axis of the polarizer layer.

[Reference example]
(A-1) Production of Polarizer Layer A polarizer layer having a thickness of 30 μm in which iodine was oriented on a uniaxially stretched polyvinyl alcohol film was produced.

(B-1) Preparation of Resin Layer A film obtained by subjecting a triacetyl cellulose film (“KC4FR-1” manufactured by Konica Minolta Opto Co., Ltd., thickness 43 μm) to saponification was prepared as a resin layer. This film is a stretched film and contains a plasticizer.

(B-2) Preparation of Protective Film A film obtained by subjecting a triacetyl cellulose film having a thickness of 83 μm to saponification treatment as a protective film was prepared. A hard coat layer was formed on one side of the triacetyl cellulose film.

(C-1) Production of Laminated Film Next, in the same manner as in the above examples and comparative examples, the water-based adhesive composition obtained in the production example was formed on one surface of the resin layer in (b-1). Was applied.
Separately from this, the aqueous adhesive composition was applied to the surface of the protective film (b-2) where the hard coat layer was not formed in the same manner as the resin layer.

Using a nip roll, one surface of the polarizer layer prepared in (a-1) above and the resin layer prepared in (b-1) were bonded together via the aqueous adhesive composition. . Moreover, the other surface of the polarizer layer and the protective film prepared in the above (b-2) were bonded via the aqueous adhesive composition. In this way, a laminate was produced. At this time, the slow axis of the resin layer and the absorption axis of the polarizer layer were made substantially parallel.
Next, the obtained laminate was passed through a drying furnace while maintaining the tension, and the aqueous adhesive composition was dried. Furthermore, the laminate was cured at 40 ° C. and 23% RH for 72 hours to obtain a laminated film.

  A pressure-sensitive adhesive layer (thickness: 15 μm) having a storage elastic modulus of about 0.7 MPa was formed on the other surface of the resin layer. The laminated film was bonded to one side of the glass plate via this pressure-sensitive adhesive layer to obtain an evaluation sample. The obtained evaluation samples were left in an environment of a temperature of 65 ° C. and a humidity of 90% RH for 250 hours in the same manner as the above “Evaluation of heat and humidity resistance of laminated film”, and the visibility corrected polarization degree before and after being left was compared.

  As a result of evaluation, ΔPy in the laminated film of the reference example was 0.3% or less. From this result, when the slow axis of the resin layer and the absorption axis of the polarizer layer are substantially parallel, even if the adhesive composition does not contain an oxetane compound having an ether bond in the main chain, ΔPy is 0. .3 or less, and it was shown that a high degree of polarization was maintained even in a humid heat environment.

  From the above, it was confirmed that the present invention is useful.

  The present invention can be used as a polarization supply element or a polarization detection element in a display device such as a liquid crystal display device.

  1, 2 ... laminated film, 11 ... polarizer layer, 21 ... resin layer, 23 ... protective film, 31, 33 ... adhesive layer

Claims (3)

A polarizer layer in which a dichroic dye is oriented in a polyvinyl alcohol resin;
A resin layer having a resin film having a slow axis in a direction oblique to the absorption axis of the polarizer layer; and
An adhesive layer that bonds the polarizer layer and the resin layer;
The resin layer includes a plasticizer,
The adhesive layer includes, as a forming material, a cured product of an adhesive composition containing an oxetane compound,
The oxetane compound is a laminated film having an ether bond in the main chain.   The laminated film according to claim 1, wherein the oxetane compound includes a plurality of oxetane rings.   The laminated film according to claim 1 or 2, wherein the polarizer layer and the resin layer are both long.

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