JP6728650B2 - Optical laminated film and its manufacturing method, polarizing plate and liquid crystal display device - Google Patents

Description

The present invention relates to an optical laminated film, a method for manufacturing the same, a polarizing plate and a liquid crystal display device.

Liquid crystal display devices are widely used as liquid crystal displays for televisions, notebook computers, smartphones, and the like. A liquid crystal display device usually includes a liquid crystal cell and a pair of polarizing plates sandwiching the liquid crystal cell; the polarizing plate includes a polarizer and a protective film.

Cellulose ester, polycarbonate, and cycloolefin resin are known as materials for forming the protective film. Among these, cycloolefin resins are preferably used from the viewpoint of having high heat resistance and high humidity resistance.

On the other hand, since a film containing a cycloolefin resin as a main component has high hydrophobicity, even if the film is adhered to a polarizer via an aqueous adhesive to obtain a polarizing plate, the film is sufficiently There was a problem that it was difficult to obtain good adhesiveness. Therefore, a laminated film including a base film containing a cycloolefin resin as a main component and an easy-adhesion layer has been proposed so that sufficient adhesiveness with a polarizer can be obtained even by using an aqueous adhesive. (For example, refer to Patent Document 1).

Further, since the liquid crystal display device for mobile use is used outdoors, it is desired that the protective film has good durability (UV resistance and oxidation resistance). As such a protective film, an optical laminate including a cycloolefin resin and an ultraviolet absorber has been proposed (for example, Patent Documents 2 and 3).

JP, 2006-171707, A JP, 2005-031753, A Japanese Unexamined Patent Publication No. 2015-045845

However, since the optical laminates of Patent Documents 2 and 3 are manufactured by the melt film-forming method, in order to suppress the bleed-out of the ultraviolet absorber during the melt film formation, only the intermediate layer contains the ultraviolet absorber. I'm out. As described above, since the optical laminated bodies of Patent Documents 2 and 3 have a multilayer structure, there is a problem that it is difficult to reduce the thickness and that delamination easily occurs.

On the other hand, a monolayer film can be obtained by producing a film containing a cycloolefin resin and an ultraviolet absorber by a cast film forming method. However, a liquid crystal display device including a polarizing plate obtained by laminating an easy-adhesion layer on the single-layer film and adhering it to a polarizer may cause optical unevenness under high temperature and high humidity.

A liquid crystal display device including a polarizing plate obtained by laminating an easy-adhesion layer on the optical layered body of Patent Documents 2 and 3 and bonding it to a polarizer has a problem that optical unevenness is more likely to occur under high temperature and high humidity. It was

The present invention has been made in view of such circumstances, and an object thereof is to provide an optical laminated film having good durability and capable of suppressing optical unevenness of a liquid crystal display device under high temperature and high humidity. To do.

[1] A base layer containing a cycloolefin resin and at least one of an ultraviolet absorber and an antioxidant, and an easy-adhesion layer containing an amide resin, a urethane resin or a silane coupling agent. In the cut surface perpendicular to the surface of the material layer, the total of the ultraviolet absorber and the antioxidant in the region S from the surface of the base material layer on which the easy-adhesion layer is arranged to the position of 0.1 t in the thickness direction. When the content is Ms and the total content of the ultraviolet absorber and the antioxidant in the region C from the center of the base material layer to the position of ±0.1 t in the thickness direction is Mc (however, the base material is The layer thickness is t), Mc/Ms is 0.01 or more and less than 1, and the residual solvent amount of the base material layer is 100 ppm or more and 2000 ppm or less.
[2] The optical laminated film according to [1], wherein the content of the ultraviolet absorber in the base material layer is 0.5 to 5 mass% with respect to the cycloolefin resin.
[3] The optical laminated film according to [1] or [2], wherein the content of the antioxidant in the base material layer is 0.5 to 5 mass% with respect to the cycloolefin resin.
[4] The optical laminated film according to any one of [1] to [3], wherein the amide resin is a water-soluble polyamide epoxy resin.
[5] The optical laminated film according to any one of [1] to [4], wherein the base material layer contains 100 to 300 ppm of toluene as the residual solvent.
[6] The optical laminated film according to any one of [1] to [5], wherein the Mc/Ms is 0.7 or less.
[7] A polarizing plate comprising the optical laminated film according to any one of [1] to [6] and a polarizer arranged on the surface of the easily adhesive layer side.
[8] A liquid crystal display device including a first polarizing plate, a liquid crystal cell, a second polarizing plate, and a backlight in this order, wherein the first polarizing plate includes a first polarizer, A protective film F1 disposed on the surface of the first polarizer opposite to the liquid crystal cell; and a protective film F2 disposed on the surface of the first polarizer on the liquid crystal cell side, The second polarizing plate includes a second polarizer, a protective film F3 disposed on a surface of the second polarizer on the liquid crystal cell side, and a side of the second polarizer opposite to the liquid crystal cell. And a protective film F4 disposed on the surface of the first polarizer, wherein at least one of the protective films F1 and F2 is the optical laminated film according to any one of [1] to [6]. Is disposed on the surface of the optical laminated film on the side of the easily adhesive layer, and/or at least one of the protective films F3 and F4 is the optical laminated film according to any one of [1] to [6]. And a liquid crystal display device in which the second polarizer is disposed on the surface of the optical laminated film on the side of the easily adhesive layer.
[9] At least one of the protective films F1 and F2 is the optical laminated film according to any one of [1] to [6], and the first polarizer is an easily adhesive layer of the optical laminated film. The liquid crystal display device according to [8], which is disposed on the side surface.
[10] A base material layer containing a cycloolefin resin and at least one of an ultraviolet absorber and an antioxidant, and a cut surface perpendicular to the surface of the base material layer having a thickness of 0.1 t from at least one surface. The total content of the ultraviolet absorber and the antioxidant in the area S up to the position is Ms, and the ultraviolet absorber and the oxidation in the area C up to the position ±0.1 t in the thickness direction from the center of the base material layer. When the total content of the inhibitor is Mc (however, the thickness of the base material layer is t), Mc/Ms is 0.01 or more and less than 1 and the residual solvent amount is 100 ppm or more and 2000 ppm or less. An amide-based resin and a urethane are formed on the step of obtaining the base material layer, the step of subjecting the surface of the base material layer forming the region S to the hydrophilic treatment, and the step of applying the hydrophilic treatment to the base material layer. A method for producing an optical layered film, comprising the steps of applying an easy-adhesion layer composition containing a base resin or a silane coupling agent, and then drying or curing the composition to form an easy-adhesion layer.

ADVANTAGE OF THE INVENTION According to this invention, the optical laminated film which has favorable durability and can suppress the optical unevenness of a liquid crystal display device under high temperature and high humidity can be provided.

It is a schematic diagram which shows an example of a structure of the optical laminated film of this invention. It is a figure explaining the area|region S and the area|region C of a base material layer in the cut surface perpendicular|vertical to the surface of a base material layer. It is a schematic diagram which shows the other example of a structure of the optical laminated film of this invention. It is a schematic diagram which shows an example of a basic structure of a liquid crystal display device.

As described above, a liquid crystal display device obtained by laminating an easy-adhesion layer on an optical layered body containing a cycloolefin resin and an ultraviolet absorber disclosed in Patent Documents 2 and 3, or obtained by simply casting a film. The liquid crystal display device obtained by laminating the easy-adhesion layer on the single layer film containing the cycloolefin resin and the ultraviolet absorber may cause optical unevenness under high temperature and high humidity.

The cause is not clear, but 1) "unevenness of adhesion" between the base layer and the easy-adhesion layer of the optical laminated film, and 2) the slow axis of the optical laminated film and the absorption axis of the polarizer under high temperature and high humidity. It is considered that there is a "axis shift". That is, the optical unevenness caused by the above 1) is that a region (a gap) that is not locally adhered is formed between the base material layer and the easy-adhesion layer, and moisture that has entered from the outside under high temperature and high humidity enters the gap. It is thought that this is due to retention. The optical unevenness due to the above 2) is such that the easily adhesive layer easily absorbs water and easily expands when the water-based adhesive is applied under high temperature and high humidity, while the base material layer containing the cycloolefin resin as the main component absorbs water. Since it is difficult to expand and it is difficult to expand, a difference occurs in the force of expansion between the two, causing distortion. It is considered that this causes the optical laminated film to warp, causing an axial deviation between the absorption axis of the polarizer and the slow axis of the optical laminated film.

On the other hand, the present inventors have found that the optical unevenness due to the above 1) can be suppressed by unevenly distributing the ultraviolet absorber or the antioxidant contained in the base material layer on the surface (see FIG. 1 described later). ). The reason for this is not clear, but it is speculated as follows. By unevenly distributing the ultraviolet absorber or the antioxidant on the surface of the base material layer, it becomes easy to stably perform hydrophilic treatment such as corona treatment before laminating the easy-adhesion layer, and easily generate many hydrophilic groups. As a result, it is possible to reduce the area (gap) in which the adhesion failure occurs between the base material layer and the easy-adhesion layer, so that it is possible to reduce the adhesion unevenness.

The present inventors have also found that the optical unevenness due to the above 2) can be suppressed by adjusting the amount of residual solvent in the base material layer to a certain level or more. The reason for this is not clear, but it is speculated as follows. The flexibility of the base material layer is enhanced by the base material layer containing a certain amount of residual solvent or more. As a result, when the water-absorbed easy-adhesion layer expands under high temperature and high humidity, the base material layer also easily follows the expansion deformation of the easy-adhesion layer. As a result, the difference in force between the two that expands is reduced, and distortion is unlikely to occur. It is considered that this suppresses the warp of the optical laminated film and suppresses the axial deviation between the absorption axis of the polarizer and the slow axis of the optical laminated film.

As described above, in the present invention, the ultraviolet absorber or the antioxidant contained in the base material layer is unevenly distributed on the surface, and the residual solvent amount in the base material layer is adjusted to be equal to or more than a certain level, thereby providing good durability. While having the above, it is possible to obtain an optical laminated film capable of suppressing optical unevenness of a liquid crystal display device under high temperature and high humidity.

1. Optical Laminated Film FIG. 1 is a schematic view showing an example of the configuration of the optical laminated film of the present invention. As shown in FIG. 1, the optical laminated film 10 of the present invention includes a base material layer 11 and an easy-adhesion layer 13.

1-1. Base Material Layer 11 The base material layer 11 contains a cycloolefin resin as a main component, and further contains at least one of an ultraviolet absorber and an antioxidant.

1-1-1. Cycloolefin Resin The cycloolefin resin is a polymer of a cycloolefin monomer or a copolymer of a cycloolefin monomer and another copolymerizable monomer.

The cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, and is a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2). Is more preferable.

R ^{1 to} R ^{4 in} formula (A-1) independently represent a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group. However, except when all of R ^{1 to} R ⁴ are hydrogen atoms, R ¹ and R ² are hydrogen atoms at the same time, or R ³ and R ⁴ are not hydrogen atoms at the same time.

The hydrocarbon group having 1 to 30 carbon atoms is preferably a hydrocarbon group having 1 to 10 carbon atoms, and more preferably a hydrocarbon group having 1 to 5 carbon atoms. The hydrocarbon group having 1 to 30 carbon atoms may further have a connecting group containing a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom. Examples of such a linking group include a carbonyl group, an imino group, a divalent polar group such as an ether bond, a silyl ether bond and a thioether bond. Examples of the hydrocarbon group having 1 to 30 carbon atoms include methyl group, ethyl group, propyl group, butyl group and the like.

Examples of the polar group include a carboxy group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amide group and a cyano group. Of these, a carboxy group, a hydroxy group, an alkoxycarbonyl group, and an allyloxycarbonyl group are preferable, and an alkoxycarbonyl group and an allyloxycarbonyl group are preferable from the viewpoint of ensuring solubility during solution film formation.

P of General formula (A-1) shows the integer of 0-2. p is preferably 1 or 2.

R ^{5 in the} general formula (A-2) represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms. Especially, a C1-C5 hydrocarbon group is preferable and a C1-C3 hydrocarbon group is more preferable.

R ^{6 in} formula (A-2) represents a carboxy group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, a cyano group, or a halogen atom (a fluorine atom, a chlorine atom, a bromine atom or iodine). Atom). Among them, a carboxy group, a hydroxy group, an alkoxycarbonyl group and an allyloxycarbonyl group are preferable, and an alkoxycarbonyl group and an allyloxycarbonyl group are more preferable from the viewpoint of ensuring the solubility during solution film formation.

P of General formula (A-2) represents the integer of 0-2. p is preferably 1 or 2.

The cycloolefin monomer represented by the general formula (A-2) has an asymmetric structure. That is, since the substituents R ⁵ and R ^{6 of the} cycloolefin monomer represented by the general formula (A-2) are substituted only on the ring-constituting carbon atoms on one side of the symmetry axis of the molecule, Has low symmetry. Such a cycloolefin monomer can accelerate the diffusion and transfer of the ultraviolet absorber and the antioxidant when the cast dope is dried in the production process of the base film described later, and thus these components It is thought that the distribution state of can be easily adjusted.

Specific examples of the cycloolefin monomer represented by the general formula (A-1) are shown in Exemplified compounds 1 to 14, and specific examples of the cycloolefin monomer represented by the general formula (A-2) are exemplified compounds. 15 to 34.

Examples of copolymerizable monomers that can be copolymerized with cycloolefin monomers include copolymerizable monomers that can be ring-opening copolymerized with cycloolefin monomers, and addition copolymerizable with cycloolefin monomers. Such copolymerizable monomers are included.

Examples of the ring-opening copolymerizable copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

Examples of the copolymerizable monomer capable of addition copolymerization include unsaturated double bond-containing compounds, vinyl cyclic hydrocarbon monomers, and (meth)acrylate. Examples of the unsaturated double bond-containing compound are olefinic compounds having 2 to 12 carbon atoms (preferably 2 to 8), and examples thereof include ethylene, propylene and butene. Examples of vinyl-based cyclic hydrocarbon monomers include vinyl-cyclopentene-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene. Examples of the (meth)acrylate include alkyl(meth)acrylates having 1 to 20 carbon atoms such as methyl(meth)acrylate, 2-ethylhexyl(meth)acrylate and cyclohexyl(meth)acrylate.

As described above, the cycloolefin-based resin is obtained by polymerizing a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by the general formula (A-1) or (A-2). It is a polymer obtained by copolymerization, and examples thereof include the following.
(1) Ring-opening polymer of cycloolefin monomer (2) Ring-opening copolymer of cycloolefin monomer and copolymerizable monomer capable of ring-opening copolymerization (3) The above (1) or (2) Hydrogenated product of ring-opened (co)polymer (4) The ring-opened (co)polymer of (1) or (2) above was cyclized by Friedel-Crafts reaction and then hydrogenated (co-polymerized). ) Polymer (5) Saturated copolymer of cycloolefin monomer and unsaturated double bond-containing compound (6) Addition copolymer of cycloolefin monomer with vinyl cyclic hydrocarbon monomer, and The hydrogenated product (7) Alternating copolymer of cycloolefin monomer and (meth)acrylate

Among them, (1) to (3) are preferable, and (3) is more preferable. That is, the cycloolefin-based resin is a structural unit represented by the following general formula (B-1) in that the glass transition temperature and the light transmittance of the obtained cycloolefin-based resin can be increased. It is preferable to include at least one of the structural units represented by the following general formula (B-2). The structural unit represented by the general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by the above general formula (A-1), and is represented by the general formula (B-2). The structural unit represented by the general formula (A-2) is a structural unit derived from the cycloolefin monomer.

X in the general formula (B-1), -CH = CH- or _-CH 2 CH ₂ -.

^R 1 to R ⁴ and p in general formula (B-1) are respectively and ^R 1 to R ⁴ and p of formula (A-1) synonymous.

X in the general formula (B-2) is, -CH = CH- or _-CH 2 CH ₂ -.

^R 5 to R ⁶ and p in the general formula (B-2) are respectively and ^R 5 to R ⁶ and p in the general formula (A-2) synonymous.

All of the cycloolefin resins can be obtained by known methods, for example, the methods described in JP-A-2008-107534, JP-A-2005-227606 and JP-A-4466272. For example, the polymer (3) hydrogenates the double bond of the main chain of the obtained ring-opening polymer after solution polymerization of the monomer. The catalyst is removed (decatalyst) from the polymer obtained after hydrogenation, and further dried under reduced pressure to remove the solvent (desolvate) to obtain the polymer (3). The amount of residual solvent in the substrate layer of the obtained optical laminated film is adjusted by removing the solvent from the ring-opening polymer and the type of solvent used for solution polymerization when synthesizing the cycloolefin resin. It can be performed by adjusting the drying conditions when the solvent is used.

Intrinsic viscosity [η] inh of cycloolefin resin is preferably 0.2~5cm ³ / g, more preferably 0.3~3cm ³ / g, 0.4~1.5cm ³ /G is more preferable.

The number average molecular weight (Mn) of the cycloolefin resin is preferably 8000 to 100,000, more preferably 10,000 to 80,000, and further preferably 12,000 to 50,000. The weight average molecular weight (Mw) of the cycloolefin resin is preferably 20,000 to 300,000, more preferably 30,000 to 250,000, and further preferably 40,000 to 200,000. The number average molecular weight and the weight average molecular weight of the cycloolefin resin can be measured by gel permeation chromatography (GPC) in terms of polystyrene.

When the intrinsic viscosity [η] inh, the number average molecular weight, and the weight average molecular weight are in the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties of the cycloolefin resin and the processability as a film are improved. ..

The glass transition temperature (Tg) of the cycloolefin resin is usually 110° C. or higher, preferably 110 to 350° C., more preferably 120 to 250° C., and 120 to 220° C. More preferable. When Tg is 110° C. or higher, it is easy to suppress deformation under high temperature conditions. On the other hand, when the Tg is 350° C. or lower, the molding process becomes easy, and the deterioration of the resin due to heat during the molding process is easily suppressed.

The content of the cycloolefin-based resin is preferably 70% by mass or more, and more preferably 80% by mass or more, based on the base material layer 11.

1-1-2. Ultraviolet absorber The ultraviolet absorber is added for the purpose of improving the durability of the optical laminated film. Such an ultraviolet absorber is preferably a compound that absorbs ultraviolet rays having a wavelength of 400 nm or less, and specifically, the transmittance of light having a wavelength of 370 nm is 10% or less, preferably 5% or less, more preferably 2%. The following compounds.

Examples of UV absorbers include oxybenzophenone compounds, benzotriazole compounds, salicylate compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders, and polymer UV absorbers. Agents are included. The ultraviolet absorber may be one kind or a combination of two or more kinds.

Among these, benzotriazole compounds, benzophenone compounds and triazine compounds are preferable, and benzotriazole compounds and benzophenone compounds are more preferable, because they have good ultraviolet absorption ability.

Examples of the benzotriazole-based compound include 5-chloro-2-(3,5-di-sec-butyl-2-hydroxylphenyl)-2H-benzotriazole and (2-2H-benzotriazol-2-yl)-. 6-(linear and side chain dodecyl)-4-methylphenol is included. Examples of the benzophenone compound include 2-hydroxy-4-benzyloxybenzophenone and 2,4-benzyloxybenzophenone.

Examples of commercially available products include Tinuvin series such as Tinuvin109, Tinuvin171, Tinuvin234, Tinuvin326, Tinuvin327, Tinuvin328, Tinuvin928 and the like, all of which are commercially available products from BASF.

The content of the ultraviolet absorber (total content in the base material layer 11) is preferably, for example, 0.1 to 10 mass% with respect to the cycloolefin resin. When the content of the ultraviolet absorber is 0.1% by mass or more, the durability (particularly weather resistance) of the optical laminated film can be sufficiently enhanced. When the content of the ultraviolet absorber is 10% by mass or less, the transparency of the optical laminated film is not easily impaired. The content of the ultraviolet absorber is more preferably 0.5 to 5% by mass.

1-1-3. Antioxidant (deterioration inhibitor)
The antioxidant may be added for the purpose of suppressing deterioration of the optical laminated film under high temperature and high humidity. Examples of antioxidants include hindered phenolic compounds. Examples of the hindered phenol compound include 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]. , Triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl- 4-Hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, 2,2- Thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N, N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t) -Butyl-4-hydroxybenzyl)benzene, tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanate and the like are included. The antioxidant may be one kind or a combination of two or more kinds.
Among them, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3 -(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate] is preferred.

Examples of the antioxidant include hydrazine-based metal deactivators such as N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine and tris(2,4-). It may be used in combination with a phosphorus-based processing stabilizer such as di-t-butylphenyl)phosphite.

The content of the antioxidant (total content in the base material layer 11) is preferably 0.1 to 10 mass% with respect to the cycloolefin resin, for example. When the content of the antioxidant is 0.1% by mass or more, the durability (particularly weather resistance) of the optical laminated film can be sufficiently enhanced. When the content of the antioxidant is 10% by mass or less, the transparency of the optical laminated film is less likely to be impaired. The content of the antioxidant is more preferably 0.5 to 5% by mass.

1-1-4. Other Components The base material layer 11 may further contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include plasticizers, heat stabilizers, fine particles (matting agents), surfactants, fluorochemical surfactants, release aids, and the like.

(Fine particles)
The fine particles can give unevenness to the surface of the base material layer and improve slipperiness. The fine particles may be inorganic fine particles or organic fine particles. Examples of inorganic fine particles are fine particles of inorganic oxides such as silica, titania, alumina, zirconia; calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrous calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate. And the like are included. Examples of organic fine particles include fine particles of silicone resin, fluororesin, (meth)acrylic resin, and the like. Among them, silica particles are preferable because they are less likely to cause haze and less colored.

The average particle diameter of the fine particles is preferably 1 nm to 500 nm, more preferably 5 nm to 300 nm. By setting the average particle size to 1 nm or more, the slipperiness of the easy-adhesion layer can be effectively enhanced, and by setting it to 500 nm or less, the haze can be suppressed low. The average particle diameter of the fine particles is the particle diameter (50% volume cumulative diameter D50) at which the cumulative volume calculated from the smaller diameter side in the measured particle diameter distribution is 50% by measuring the particle diameter distribution by the laser diffraction method.

The content of the fine particles may be 10% by mass or less with respect to the base material layer 11.

The base material layer 11 is preferably subjected to a hydrophilization treatment from the viewpoint of further enhancing the adhesiveness with the easy-adhesion layer 13. By applying the hydrophilic treatment, the hydrophilicity of the surface of the base material layer 11 can be enhanced, and the adhesiveness with the easily adhesive layer 11 can be enhanced. The hydrophilic treatment is preferably performed on at least the adhesive surface of the base material layer 11 with the easy-adhesion layer 13.

Examples of the hydrophilic treatment include corona (discharge) treatment, plasma treatment, flame treatment, itro treatment, glow treatment, ozone treatment, primer coating treatment, etc., as described later, and from the viewpoint of productivity, corona treatment is preferable. Processing or plasma processing.

1-1-5. Physical properties of the base material layer 11 (content distribution of ultraviolet absorber/antioxidant)
It is preferable that at least one of the ultraviolet absorber and the antioxidant is unevenly distributed on at least the surface of the base material layer 11 on which the easy-adhesion layer 13 is arranged (see FIG. 1 ). In the example of FIG. 1, the dark gradation area shows the area where the ultraviolet absorber and the antioxidant are unevenly distributed.

Specifically, in the cut surface perpendicular to the surface of the base material layer 11, the total content of the ultraviolet absorber and the antioxidant in the region C (intermediate layer region) of the base material layer 11 is Mc, and the base material layer 11 When the total content of the ultraviolet absorber and the antioxidant in the region S including the surface on which the easy-adhesion layer 13 is arranged is Ms, Mc/Ms is preferably 0.01 or more and less than 1, and 0. It is more preferably from 01 to 0.7. When Mc/Ms is less than 1, preferably 0.7 or less, the ultraviolet absorber or the antioxidant is unevenly distributed on the surface of the base material layer 11 on which the easily adhesive layer 13 is arranged. The polymer chain of cycloolefin resin is difficult to move and is easily fixed. Thereby, a hydrophilic group such as an OH group is likely to be stably generated by a hydrophilic treatment such as a corona treatment, and the easily adhesive layer is laminated on the surface of the base material layer 11 on which the hydrophilic group is stably generated. Uniform and good adhesiveness is easily obtained between the base material layer 11 and the easy-adhesion layer 13.

FIG. 2 is a diagram illustrating a region S and a region C of the base material layer 11 on a cut surface perpendicular to the surface of the base material layer 11. In the figure, the upper side is the side where the easy-adhesion layer 13 is arranged. As shown in FIG. 2, the region S represents a surface layer region from the surface of the base material layer 11 on which the easy-adhesion layer is arranged to a position of 0.1 t (t: thickness of the base material layer 11) in the thickness direction. , Region C indicates the intermediate layer region from the center of the base material layer 11 to the position of ±0.1 t in the thickness direction.

It suffices that the region S including the surface of the base material layer 11 on which the easy adhesion layer is arranged satisfies Mc/Ms of less than 1 (see FIGS. 1 and 2), but the easy adhesion layer 13 of the base material layer 11 is When the total content of the ultraviolet absorber and the antioxidant in the region S′ including the surface not arranged is Ms′, Mc/Ms′ is 0.01 or more and less than 1, preferably 0.01 or more and 0.7. The following may be further satisfied (see FIGS. 3 and 2).

The distribution state or Mc/Ms of the ultraviolet absorber or the antioxidant in the base material layer 11 can be measured by the following method. That is,
1) The optical laminated film 10 is cut with a microtome to obtain a cut surface perpendicular to the surface of the optical laminated film 10.
2) Of the cut surface of the obtained optical laminated film 10, a surface distribution image of organic substances in a measurement area including the area S and the area C of the base material layer 11 is measured by ATR method using Nicolet 380 manufactured by Thermo Fisher Scientific. To do. The measurement region may be a region of 1.5t×1.5t, where t is the thickness of the base material layer.
3) The peak of the ultraviolet absorber or the antioxidant to be measured (peak to be measured) is extracted, the content is quantified from the absorbance, and a visualized IR image image is obtained. From the IR image image, the distribution state of the ultraviolet absorber or the antioxidant on the cut surface of the base material layer 11 is grasped.
The value of Mc/Ms can be obtained from the ratio of the integrated value of the absorbance of the measurement target peak in the region S and the integrated value of the absorbance of the measurement target peak in the region C in the measurement region. The peak to be measured shall be measured in advance. The value of Mc/Ms' can be measured in the same manner.

Mc/Ms can be adjusted by, for example, the solvent composition of the dope or the residual solvent amount of the film-shaped material before drying in the manufacturing process of the base material layer 11. In order to unevenly distribute the ultraviolet absorber/antioxidant on the surface layer of the base material layer 11, it is preferable to reduce the amount of residual solvent in the film material before drying. It is preferable to increase the content ratio of the solvent (low-boiling point solvent) and reduce the residual solvent amount of the film material before drying. If the amount of residual solvent in the film material before drying is reduced, it is not clear why it is easy to adjust Mc/Ms to the above range (the ultraviolet absorber and the antioxidant are likely to be unevenly distributed on the surface). It is considered that when the amount of residual solvent of the film-form material before drying is small, the ultraviolet absorber and the antioxidant in the vicinity of the surface of the film-form product are hard to volatilize and are likely to be concentrated on the surface of the film-form product. ..

(Amount of residual solvent)
The amount of residual solvent contained in the base material layer 11 is preferably 100 to 2000 ppm. When the amount of residual solvent is 100 ppm or more, the base material layer 11 may have appropriate flexibility. Thereby, when the water-based adhesive is applied to the easy-adhesion layer 13 of the optical laminated film 10 and is bonded to the polarizer, the base material layer 11 easily follows the force of the easy-adhesion layer 13 absorbing and expanding. Is less likely to be distorted. As a result, axial misalignment between the slow axis of the optical laminated film and the absorption axis of the polarizer hardly occurs, and optical unevenness can be suppressed. When the amount of residual solvent is 2000 ppm or less, the strength of the base material layer 11 is less likely to be impaired. The residual solvent amount in the base material layer 11 is more preferably 100 to 800 ppm.

The base material layer 11 preferably contains 100 to 300 ppm of toluene as a residual solvent. Since toluene has low polarity, it has good compatibility with cycloolefin resins. Therefore, since the fluidity of the resin is easily secured in the base material layer 11 (the polymer chains are easy to move), the base material layer 11 containing it easily follows the expansive deformation when the easy-adhesion layer 13 absorbs water. Cheap. As a result, warpage of the optical laminated film can be suppressed, and optical unevenness can be further suppressed.

The qualitative and quantitative determination of the residual solvent contained in the base material layer 11 can be performed by headspace gas chromatography. That is, in headspace gas chromatography, the sample is sealed in a container and heated, and the gas in the container is quickly injected into the gas chromatograph while the container is filled with volatile components, and the compound is identified by mass spectrometry. The volatile components are quantified while performing. The volatile component can be quantified by preparing a calibration curve in advance using a sample having a known concentration, and comparing the peak area of the volatile component obtained by the measurement with the calibration curve. Specific measuring devices and measuring conditions are the same as those in the examples described later.

The amount of residual solvent contained in the base material layer 11 depends on the drying conditions when the solvent is removed during the synthesis of the cycloolefin-based resin described above; the drying conditions of the film-like material during the production of the base material layer 11 (see (1- It can be adjusted by the drying conditions) in the step 3). In order to keep the amount of residual solvent contained in the base material layer 11 above a certain level, the drying temperature at the time of solvent removal in the synthesis of the cycloolefin resin may be lowered; The drying temperature in the step (1) may be lowered.

(Thickness)
The thickness of the base material layer 11 is, for example, 10 to 200 μm, preferably 10 to 100 μm, and preferably 15 to 60 μm, from the viewpoint of satisfying the ranges of Ro and Rth of the optical laminated film 10 described later and reducing the thickness. It is more preferable that the thickness is 15 to 30 μm.

1-2. About the Easy-Adhesion Layer 13 The easy-adhesion layer 13 has a function of imparting a function of enhancing the adhesiveness with a polarizer, for example. The easy-adhesion layer 13 is preferably a layer that can enhance the adhesiveness particularly when a water-based adhesive is used.

1-2-1. About the main component The easy-adhesion layer 13 has as its main component a coupling agent having a hydrolyzable hydrophilic group and an organic functional group (reactivity of amino group, vinyl group, epoxy group, mercapto group, chloro group, etc.). A silane coupling agent having a functional group and a hydrolyzable alkoxysilyl group; a titanate coupling agent having a hydrolyzable hydrophilic group containing titanium and an organic functional group; a hydrolyzable group containing aluminum Aluminate coupling agent having a hydrophilic group and an organic functional group); or an amide resin, an epoxy resin, an isocyanate resin and a resin having an organic reactive group such as a urethane resin are preferably contained. ..

Among them, the easy-adhesion layer 13 preferably contains an amide-based resin, a urethane-based resin, or a silane-based coupling agent, and preferably an amide-based resin or a silane-based coupling agent, from the viewpoint that the adhesiveness can be favorably improved. More preferable.

(Amide resin)
The amide resin is preferably a water-soluble polyamide epoxy resin. The water-soluble polyamide epoxy resin is obtained by reacting a polycondensation product of polyamine and polycarboxylic acid with epihalohydrin.

The polyamine is a tri- or higher functional amine, preferably a tri-functional amine. The polyamine is preferably an aliphatic polyamine. The polycarboxylic acid is a bifunctional or higher functional carboxylic acid, preferably a bifunctional carboxylic acid. The polycarboxylic acid is preferably an aliphatic polycarboxylic acid. Epihalohydrin is preferably epichlorohydrin.

Examples of commercially available water-soluble polyamide epoxy resins are Sumirez Resin (registered trademark) 6615, 650(30), 675A manufactured by Taoka Chemical Industry Co., Ltd., WS series manufactured by Seiko PMC, Arakawa Chemical Industry Co., Ltd. ) Arafix 530, 504 and the like are included.

(Urethane resin)
The urethane-based resin contains a repeating unit derived from a reaction product of (i) a polyhydric alcohol component and (ii) a polyvalent isocyanate component.

Examples of the (i) polyhydric alcohol component include a polyol compound, a polyether polyol, a polyester polyol, a polyether ester polyol, and a polycarbonate polyol. These polyhydric alcohol components may be used alone or in combination of two or more.

Examples of the polyol compound include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tricyclodecane dimethanol, 1,4-cyclohexanediene. Methanol, 2,2-dimethylpropanediol, 1,4-butanediol and the like are included.
Examples of the polyether polyol include alkylene oxide adducts of the above-mentioned polyol compounds; ring-opening (co)polymers of alkylene oxide and cyclic ether (for example, tetrahydrofuran); polyethylene glycol, polypropylene glycol, and ethylene glycol-propylene glycol copolymers. Polymers; glycols such as glycol and polytetramethylene glycol are included.
Examples of polyester polyols include dicarboxylic acids such as adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, and phthalic acid, or anhydrides thereof, and polyol compounds such as ethylene glycol and propylene glycol, and hydroxyl groups. Included are those that have been polycondensed under excess conditions.
Examples of the polyether ester polyol include polytetramethylene glycol-adipic acid condensate.
An example of the polycarbonate polyol is represented by the general formula: HO-R-(OC(O)-OR)x-OH (R represents a saturated fatty acid polyol residue having 1 to 12 carbon atoms, and x represents The number of repeating units of the molecule is shown and is an integer of 5 to 50) and the like.

(Ii) Examples of the polyvalent isocyanate component include aliphatic, alicyclic or aromatic compounds containing two or more isocyanate groups in one molecule. The aliphatic diisocyanate compound is preferably an aliphatic diisocyanate having 1 to 12 carbon atoms, and examples thereof include hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and hexane diisocyanate (HDI). The alicyclic diisocyanate compound is preferably an alicyclic diisocyanate having 4 to 18 carbon atoms, and examples thereof include 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate. (HMDI) is included. Examples of aromatic isocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate.

The urethane resin preferably contains an acid structure. This is because even if the amount of the surfactant added is small, the surfactant can be dispersed in water, and the water resistance of the easy-adhesion layer is improved. This is called a self-emulsifying type, which means that the urethane resin can be dispersed and stabilized in water by using only a molecular ionic property without using a surfactant.

Examples of the acid structure include an acid group such as a carboxyl group (-COOH) and a sulfonic acid group (-SO3H). The acid structure may be present at the side chain or at the terminal of the urethane resin.

The acid value of the urethane resin is preferably 20 to 250 mgKOH/g, more preferably 25 to 150 mgKOH/g. When the acid value is less than 20 mgKOH/g, the water dispersibility tends to be insufficient, and when the acid value is more than 250 mgKOH/g, the water resistance of the easily adhesive layer tends to be poor.

Part or all of the acid structure is preferably neutralized. By neutralizing the acid structure, the water dispersibility of the urethane resin can be improved. Examples of neutralizing agents for neutralizing the acid structure include organic amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyldiethanolamine and triethanolamine; inorganic bases such as sodium hydroxide and potassium hydroxide. included.

Examples of commercially available urethane resins include "Superflex" series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., and the like.

(Silane coupling agent)
Examples of the silane coupling agent include isocyanate group-containing alkoxysilanes such as γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-isocyanatepropylmethyldiethoxysilane, and γ-isocyanatepropylmethyldimethoxysilane. Γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ- (2-Aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-ureidopropyltrimethoxysilane, N Amino group-containing alkoxysilanes such as -phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane and N-vinylbenzyl-γ-aminopropyltriethoxysilane; γ-mercaptopropyltrimethoxy Alkoxysilanes containing mercapto group such as silane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Epoxy group-containing alkoxy such as propyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane Silanes; carboxy-containing alkoxysilanes such as β-carboxyethyltriethoxysilane, β-carboxyethylphenylbis(2-methoxyethoxy)silane, N-β-(carboxymethyl)aminoethyl-γ-aminopropyltrimethoxysilane A vinyl type unsaturated group-containing alkoxysilane such as vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyltriethoxysilane; γ-chloropropyltrimethoxysilane, etc. Halogen group-containing alkoxysilanes; isocyanate group-containing alkoxysilanes such as tris(trimethoxysilyl)isocyanate, Included are amino-modified silyl polymers, silylated amino polymers, unsaturated aminosilane complexes, phenylamino long chain alkylsilanes, aminosilylated silicones, silylated polyesters, and derivatives thereof.

The content of the amide-based resin, the urethane-based resin, or the silane-based coupling agent is preferably 60% by mass or more with respect to the easy-adhesion layer 13. When the content of these components is 60% by mass or more, good adhesiveness to the polarizer is easily obtained. The content of the amide-based resin, urethane-based resin or silane-based coupling agent is more preferably 80% by mass or more, further preferably 90% by mass or more.

1-2-2. Other Components The easy-adhesion layer 13 may further contain other components, if necessary. Examples of the other component include fine particles (matting agent) and the like. As the fine particles (matting agent), the same fine particles (matting agent) that can be contained in the base material layer 11 can be used.

1-2-3. Physical Properties of Easy-Adhesion Layer The thickness of the easy-adhesion layer 13 is not particularly limited, but may be in the range where an effect of improving the adhesion is obtained, and is preferably 0.001 to 10 μm. When the thickness of the easy-adhesion layer 13 is 0.001 μm or more, it is easy to obtain sufficient adhesiveness with the polarizer when the water-based adhesive is used. When the thickness of the easy-adhesion layer 13 is 10 μm or less, it is possible to prevent the resulting polarizing plate from being excessively thick. The thickness of the easy-adhesion layer 13 is more preferably 0.01 to 1 μm.

1-3. Physical properties of optical laminated film 10 (retardation value)
The optical laminated film 10 can take various retardation values depending on the application. For example, when the optical laminated film is used as an optical film of a VA mode or IPS mode liquid crystal display device, the optical laminated film 10 has an in-plane direction measured in an environment of a measurement wavelength of 590 nm and 23° C. and 55% RH. The retardation Ro and the retardation Rth in the thickness direction may satisfy the following relationship, for example.
0 nm≦Ro≦300 nm
-200 nm≦Rth≦200 nm

The retardation Ro in the in-plane direction of the optical laminated film 10 more preferably satisfies 5≦Ro≦250 nm, and further preferably 50 nm≦Ro≦200 nm. The retardation Rth in the thickness direction of the optical laminated film 10 more preferably satisfies −150 nm≦Rth≦150 nm, more preferably −120 nm≦Rth≦120 nm.

Ro and Rth of the optical laminated film 10 are respectively defined by the following formulas.
Formula (2a): Ro=(nx−ny)×d
Formula (2b): Rth=((nx+ny)/2-nz)*d
(In the formula,
nx represents the refractive index in the in-plane slow axis direction of the optical laminated film,
ny represents the refractive index in the direction orthogonal to the in-plane slow axis of the optical laminated film,
nz represents the refractive index in the thickness direction of the optical laminated film,
d represents the thickness (nm) of the optical laminated film. )

The in-plane slow axis of the optical laminated film 10 refers to an axis having the maximum refractive index on the film surface. The in-plane slow axis of the optical laminated film can be confirmed by an automatic birefringence meter Axoscan (Axo Scanning Mueller Matrix Polarimeter: manufactured by Axometrics).

The Ro and Rth of the optical laminated film 10 can be measured by the following method.
1) The optical laminated film 10 is conditioned at 23° C. and 55% RH for 24 hours. The average refractive index of this optical laminated film is measured with an Abbe refractometer, and the thickness d is measured with a commercially available micrometer.
2) The retardation Ro and Rth at the measurement wavelength of 590 nm of the optical laminated film 10 after humidity adjustment were respectively measured using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics Co., Ltd.). It is measured under the environment of %RH. In particular,
The R _o when the light is incident in parallel to the measurement wavelength 590nm in the normal direction of i) a film plane, measured at A shit scan.
ii) Furthermore, by AXOSCAN, the in-plane slow axis of the sample piece was used as the tilt axis (rotation axis), and the measurement wavelength of 590 nm from the angle θ (incident angle (θ)) with respect to the normal to the surface of the sample piece. The phase difference R(θ) when light was incident was measured. The phase difference R(θ) is measured at 6 points every 10° in the range of 0° to 50°. The in-plane slow axis of the sample piece is confirmed by an Axoscan.
iii) Axoscan calculates nx, ny, and nz from the measured Ro and R(θ), and the above-described average refractive index and thickness, and Rth at the measurement wavelength of 590 nm is calculated based on the above formula (2b). calculate.

(Thickness)
The thickness of the optical laminated film 10 is, for example, 10 to 210 μm, preferably 10 to 110 μm, and more preferably 15 to 70 μm, from the viewpoint of satisfying the above ranges of Ro and Rth and making the optical device thinner. More preferably, it is 15 to 40 μm.

2. Method for producing optical laminated film The optical laminated film of the present invention comprises 1) a cycloolefin resin, at least one of an ultraviolet absorber and an antioxidant, and Mc/Ms satisfies 0.01 or more and less than 1, and A step of obtaining the above-mentioned base material layer 11 (hereinafter, also referred to as “base material film”) in which the amount of residual solvent satisfies 100 ppm or more and 2000 ppm or less, and 2) a hydrophilic treatment is applied to the surface constituting the region S of the base material film. It is manufactured through a step of applying and 3) a step of applying the composition for an adhesive layer to the surface of the substrate film which has been subjected to the hydrophilic treatment and then drying or curing the composition to obtain an adhesive layer.

Step 2-1-1) Cycloolefin resin and at least one of an ultraviolet absorber and an antioxidant are contained, Mc/Ms satisfies 0.01 or more and less than 1, and the residual solvent amount is 100 ppm or more and 2000 ppm. A substrate film satisfying the following is obtained. The Mc/Ms of the base film is defined similarly to the Mc/Ms of the optical film. That is, Ms in the base film indicates the total content of the ultraviolet absorber and the antioxidant in the region S including the surface of the base film on which the easily adhesive layer is arranged.

Such a substrate film is specifically (1-1) a step of dissolving the cycloolefin resin described above and at least one of the ultraviolet absorber and the antioxidant described above in a solvent to obtain a dope, (1-2) After casting the dope on the support, peeling the dope to obtain a film, and (1-3) drying the film. In the method for producing a base material film, it is preferable to further perform a step of stretching the (1-4) film-like material between (1-2) and (1-3).

Step (1-1) At least a cycloolefin resin and at least one of an ultraviolet absorber and an antioxidant are dissolved in a solvent to obtain a dope. The dope may be obtained by simultaneously mixing and dissolving a cycloolefin resin and at least one of an ultraviolet absorber and an antioxidant in a solvent, or a resin solution in which a cycloolefin resin is dissolved in a solvent, and an ultraviolet absorber. And at least one of the antioxidants may be mixed with an additive solution in which a solvent is dissolved to obtain a dope.

The solvent used for the dope is selected so that the residual solvent amount in the base material layer of the optical laminated film falls within the above range. In order to obtain a transparent base film free of foreign matter such as gel, it is necessary to mix the cycloolefin resin and the solvent uniformly, so it is preferable to include at least one good solvent for the cycloolefin resin. ..

Examples of the good solvent include organic halogen compounds such as methylene chloride and chloroform, toluene, methyl acetate, acetone, dioxolane and the like. Among them, methylene chloride is preferable because it easily dissolves the cycloolefin resin.

The solvent used for preparing the dope may further include a poor solvent for the cycloolefin resin, if necessary. Examples of the poor solvent include linear or branched aliphatic alcohols having 1 to 4 carbon atoms such as methanol, ethanol and n-butanol, and tetrahydrofuran.

When a good solvent and a poor solvent are used in combination, it is preferable to increase the content ratio of the good solvent (low boiling point solvent) in order to set Mc/Ms in the above range. Although it depends on the conditions (time and temperature) at the time of removing the solvent, increasing the content ratio of the good solvent (low boiling point solvent) makes it easy to adjust the residual solvent amount of the film material before drying to a certain level or less. is there. Specifically, the content ratio of the good solvent is 51 to 100 mass% (preferably 70 to 99 mass%, more preferably 80 to 99 mass%), and the content ratio of the poor solvent is 0 to 49 mass% (preferably 1 to 30% by mass, more preferably 1 to 20% by mass).

The resin concentration of the dope is preferably high from the viewpoint of reducing the drying load after casting on the metal support, but the load during filtration increases and the filtration accuracy deteriorates. The resin concentration of the dope satisfying both of these requirements is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass.

The resin can be dissolved by a general method. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure. It is preferable to dissolve with stirring while heating at a temperature not lower than the boiling point of the solvent under normal pressure and under which the solvent does not boil under pressure, in order to prevent generation of lumpy undissolved substances. Alternatively, the resin may be mixed with a poor solvent to wet or swell, and then a good solvent may be further added to dissolve the resin.

The pressurization can be carried out by a method of injecting an inert gas such as nitrogen gas, or a method of expressing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

The heating temperature for melting the resin is preferably higher from the viewpoint of the solubility of the resin, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates. The heating temperature is preferably 45 to 120°C, more preferably 60 to 110°C, and further preferably 70°C to 105°C.

From the viewpoint of suppressing foreign matter failure, it is preferable to filter the obtained dope with a filter material. After defoaming the filtered dope, it is supplied to the casting die by a liquid feeding pump.

Step (1-2) The obtained dope is discharged from a casting die and cast on a metal support, and the obtained cast film is dried and peeled to obtain a film-like material.

The metal support can be a stainless steel belt or a drum whose surface is plated with a casting. The surface of the metal support is preferably mirror-finished.

The surface temperature of the metal support is preferably −50° C. to a temperature lower than the boiling point of the solvent, and the higher the temperature is, the higher the drying speed of the film-like material can be increased. The flatness may deteriorate. Therefore, the surface temperature of the metal support is preferably 0 to 40°C, more preferably 5 to 30°C.

The amount of residual solvent (the amount of residual solvent before drying) of the film-like substance at the time of peeling from the metal support is 1 to 10% by mass in order to set Mc/Ms of the obtained base film to the above range. It is preferably present, and more preferably 5 to 9 mass %.

The residual solvent amount of the film is defined by the following formula.
Residual solvent amount (mass %)={(M−N)/N}×100
(M indicates the mass of the film material, and N indicates the mass after heating the film material at 120° C. for 1 hour)

The film-like material obtained by peeling may be further dried if necessary.

Step (1-4) It is preferable to stretch the film obtained by peeling to adjust the retardation.

The stretching can be performed in at least one direction. The stretching direction may be any of the longitudinal direction (MD direction) of the film, the width direction (TD direction) orthogonal to the longitudinal direction of the film, and the oblique direction with respect to the longitudinal direction of the film. Good. The stretching may be sequential stretching or simultaneous stretching.

For example, when the optical laminated film is made to function as a λ/4 film described later, it is preferably stretched in an oblique direction. The stretching in the oblique direction is such that the in-plane slow axis of the obtained optical laminated film is 20 to 70°, preferably 30 to 60°, and more preferably 40 to 50° with respect to the longitudinal direction of the film-like material. Can be set to. When the optical laminated film is made to function as a retardation film for VA, it is preferable to stretch the film in the width direction (TD direction).

The stretch ratio depends on the required optical performance, but may be 1.03 to 2.00 in order to obtain an optical laminated film that can function as a λ/4 film or a retardation film for VA, for example. The stretch ratio is defined as (the size in the stretching direction of the laminate after stretching)/(the size in the stretching direction of the laminate before stretching).

When the glass transition temperature of the cycloolefin resin is Tg, the stretching temperature is preferably Tg-30°C to Tg+60°C, more preferably Tg-10°C to Tg+50°C.

The amount of residual solvent in the film at the start of stretching is preferably 20 to 100% by mass. The amount of residual solvent in the film at the end of stretching is 10% by mass or less, preferably 5% by mass or less.

Stretching in the MD direction can be performed, for example, by a method in which a plurality of rolls are provided with a peripheral speed difference and the roll peripheral speed difference is used between them. The stretching in the TD direction can be performed, for example, by fixing both ends of the film-like material with clips or pins and widening the intervals between the clips or pins in the traveling direction. These may be combined. Stretching in the oblique direction is preferably performed by an oblique stretching device. As an oblique stretching device, by changing the rail pattern in various ways, it is possible to freely set the orientation angle (the angle of the in-plane slow axis with respect to the longitudinal direction) of the obtained substrate film, and to adjust the orientation axis of the substrate film. It is preferable that it can be uniformly oriented in the left-right direction with high precision in the width direction.

Step (1-3) The film-like material obtained in (1-2) or (1-4) is dried to obtain a base film. The residual solvent amount of the base film can be adjusted mainly in this step. Therefore, the drying temperature and the drying time can be adjusted so that the amount of residual solvent in the obtained base film is in the above range.

The drying temperature is preferably about 40 to 250°C, more preferably 40 to 160°C. Since rapid drying tends to impair the flatness of the obtained substrate film, it is preferable to perform drying at a high temperature when the residual solvent amount of the film-shaped material is 8% by mass or less. The drying time can be adjusted depending on the solvent species used for the dope.

Drying of the film material is performed by alternately passing the film material through a plurality of rolls arranged in the drying device and drying while transporting the film material, or by gripping both ends of the film material with clips and transferring. It can be carried out by a tenter drying method in which it is dried while being dried.

The drying method is not particularly limited, and hot air, infrared rays, heating rolls, microwaves and the like can be used, and hot air is preferable from the viewpoint of simplicity.

Regarding step 2-2.2) Examples of the hydrophilic treatment include corona (discharge) treatment, plasma treatment, flame treatment, itro treatment, glow treatment, ozone treatment, and primer coating treatment. Among them, the corona treatment and the plasma treatment are preferable from the viewpoint of productivity.

Corona discharge treatment is a process of applying a high frequency/high voltage between electrodes that are insulated from the dielectric to generate corona, and passing the base film between the dielectric and the electrodes to clean the surface of the base film. It is a method of processing. Thereby, the adhesiveness of the surface of the base film is enhanced.

Examples of the material of the electrodes include ceramics and aluminum. The distance between the electrode and the dielectric is preferably 1 to 5 mm, more preferably 1 to 3 mm. The line speed (moving speed) is preferably about 3 to 70 m/min, more preferably about 3 to 50 m/min.

The corona output intensity is preferably 0.2 kW to 3 kW, more preferably 0.5 kW to 1.5 kW. If the corona output strength is less than 0.2 kW, corona discharge becomes unstable, and it may be difficult to impart a stable adhesive force to the surface of the base film. When the corona output strength is larger than 2.0 kW, the base film may be easily scratched. The electron irradiation dose in the corona discharge treatment may be 100 to 1000 W/m ² /min.

The plasma treatment is a treatment for activating the surface of the substrate film by performing plasma discharge in a gas atmosphere such as an inert gas or oxygen gas generated under reduced pressure or atmospheric pressure. Plasma treatment under atmospheric pressure is preferable for efficient production under the transportation using rolls.

The plasma treatment can variously modify the surface of the base material layer by changing the kind of gas. Therefore, when activating the surface of the base material layer, the kind of gas can be appropriately selected. Examples of the type of gas include nitrogen, oxygen, argon, helium, acrylic acid, hydroxyalkyl, CF ₄ , CHF ₃ C ₂ F _{6, and} other fluorine-based compounds.

The plasma output is preferably 0.2 kW to 3 kW. The line speed (moving speed) is preferably 3 to 70 m/min, and more preferably 3 to 50 m/min. The frequency is preferably 3 to 30 kH, more preferably 5 to 20 kH.

Step 2-3-3) The composition for easy-adhesion layer is applied to the surface of the base film that has been subjected to the hydrophilization treatment, and then dried or cured to form the easy-adhesion layer. That is, when the composition for easy-adhesion layer contains a thermosetting component (thermosetting resin and cross-linking agent), the composition for easy-adhesion layer is coated on a substrate film and then cured (heat treatment) to facilitate curing. Form an adhesive layer. When the composition for easy-adhesion layer does not contain the above-mentioned thermosetting component, the composition for easy-adhesion layer is applied onto the substrate film and then dried to form the easy-adhesion layer. Among them, from the viewpoint of improving productivity, it is preferable to form the easy-adhesion layer by applying the composition for easy-adhesion layer on the substrate film and then drying.

The composition for an easy-adhesion layer contains an amide-based resin, a urethane-based resin or a silane coupling agent, which are main components, and water or an organic solvent.

The organic solvent used is preferably one that can uniformly dissolve or disperse the silane coupling agent or the amide resin and has appropriate volatility. Examples of such organic solvents include alcohols such as methanol, ethanol and propyl alcohol, ketones such as acetone and methyl ethyl ketone, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated methylene chloride and chloroform. Hydrocarbons may be mentioned. When a silane coupling agent is used as the main component of the easy-adhesion layer, the easy-adhesion layer composition need not contain water or an organic solvent. The concentration of the amide-based resin or the silane coupling agent in the easy-adhesion layer composition may be, for example, 0.1% or more from the viewpoint of easily forming an easy-adhesion layer stably.

The composition for easy-adhesion layer may further contain a crosslinking agent, if necessary. The crosslinking agent may be a compound having a functional group that reacts with the reactive group of the resin as the main component. For example, examples of the cross-linking agent combined with the urethane-based resin include a water-based epoxy compound, a water-based amino compound, and a water-based oxazoline compound. The cross-linking agent may be one kind or a combination of two or more kinds.

The water-based epoxy compound may be a compound having two or more epoxy groups which are soluble in water or emulsified, and examples thereof include 1 mol of glycols such as ethylene glycol and diethylene glycol and 2 mol of epichlorohydrin. A diepoxy compound obtained by etherification with 1 mol of polyhydric alcohols such as glycerin, polyglycerin, and trimethylolpropane, and a polyepoxy compound obtained by etherification with 2 mol or more of epichlorohydrin; phthalic acid, terephthalic acid, shu An epoxy compound such as a diepoxy compound obtained by esterification of 1 mol of a dicarboxylic acid such as an acid or adipic acid with 2 mol of epichlorohydrin is included.

The water-based amino compound may be a compound having two or more amino groups which are soluble in water or emulsified, and examples thereof include carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, and succinic acid dihydrazide. , Adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, glycolic acid dihydrazide, polyacrylic acid dihydrazide, and other hydrazide compounds, melamine resins, urea resins, guanamine resins and the like.

The water-based oxazoline compound may be any compound that is soluble in water or has two or more emulsified oxazoline groups.

As a method for applying the composition for an easily adhesive layer, for example, a gravure coating method, a dip coating method, a spray coating method, a casting method, or the like can be adopted.

The drying temperature may be, for example, 20° C. or higher and Tg or lower of the base film. The drying time may be, for example, 1 minute or more and 10 hours or less.

In the present invention, the base film obtained in the above step 1) has an ultraviolet absorber or an antioxidant unevenly distributed on its surface (because Mc/Ms is less than 1). In the step (1), the surface of the base material film is likely to be favorably hydrophilized. As a result, in the above step 3), the adhesiveness between the surface of the base film subjected to the hydrophilization treatment and the easy-adhesion layer is enhanced, and uneven adhesion can be reduced.

3. Polarizing Plate The polarizing plate of the present invention includes a polarizer and two protective films, and at least one of the protective films can be the optical laminated film of the present invention. When the optical laminated film of the present invention is arranged on only one surface of the polarizer, another film may be arranged on the other surface of the polarizer.

3-1. Polarizer A polarizer is an element that allows only light having a plane of polarization in a certain direction to pass therethrough, and a typical polarizer currently known is a polyvinyl alcohol-based polarizing film. Polyvinyl alcohol-based polarizing films include those obtained by dyeing a polyvinyl alcohol-based film with iodine and those obtained by dyeing a dichroic dye.

The polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a dichroic dye (preferably a film further subjected to a durability treatment with a boron compound); A film obtained by dyeing an alcohol-based film with iodine or a dichroic dye and then uniaxially stretching it (preferably a film further subjected to a durability treatment with a boron compound) may be used. The absorption axis of the polarizer is usually parallel to the maximum stretching direction.

For example, the content of ethylene units described in JP-A-2003-248123 and JP-A-2003-342322 is 1 to 4 mol %, the degree of polymerization is 2000 to 4000, and the degree of saponification is 99.0 to 99.99 mol %. Ethylene-modified polyvinyl alcohol is used. Above all, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73° C. is preferably used.

The thickness of the polarizer is preferably 5 to 30 μm, and more preferably 5 to 20 μm in order to make the polarizing plate thin.

3-2. Optical Laminated Film of the Present Invention The optical laminated film of the present invention can be arranged on at least one surface of a polarizer. The easy-adhesion layer and the polarizer of the optical laminated film are preferably laminated directly or via an adhesive layer.

When the optical laminated film of the present invention is used as a λ/4 film, the angle formed between the in-plane slow axis of the optical laminated film of the present invention and the absorption axis of the polarizer is preferably 20 to 70°, The angle is more preferably 30 to 60°, further preferably 40 to 50°. When the optical laminated film of the present invention is used as a retardation film for VA, the in-plane slow axis of the optical laminated film of the present invention and the absorption axis of the polarizer may be substantially orthogonal to each other.

3-3. Other Film On the other surface of the polarizer, another film may be arranged as necessary. Examples of other films include commercially available cellulose acylate films (for example, Konica Minolta Tuck KC6UA, KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC4FR-1, KC8UY-HA, KC8UX-RHA, KC8UE, KC4UE, KC4HR-1, KC4KR-1, KC4UA, KC6UA or more manufactured by Konica Minolta Opto Co., Ltd. and the like are included.

The thickness of the other film is not particularly limited, but is preferably 10 to 100 μm, more preferably 10 to 60 μm, and particularly preferably 20 to 60 μm.

3-4. Method of Manufacturing Polarizing Plate The polarizing plate of the present invention can be obtained by laminating a polarizer and the optical laminated film of the present invention via an adhesive or a pressure-sensitive adhesive.

The adhesive may be a water-based adhesive containing a polyvinyl alcohol-based resin or a urethane-based resin as a main component, or a photo-curable adhesive containing a photo-curable resin such as an epoxy resin as a main component. The pressure-sensitive adhesive may contain an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether or the like as a base polymer. Among them, the water-based adhesive is preferable because it has good affinity with the easy-adhesion layer of the optical laminated film of the present invention and hardly causes distortion due to water absorption.

The lamination of the polarizer and the optical laminated film of the present invention can be usually performed by roll-to-roll.

4. Liquid Crystal Display Device The liquid crystal display device of the present invention includes a liquid crystal cell and a pair of polarizing plates sandwiching the liquid crystal cell.

FIG. 4 is a schematic diagram showing an example of the basic configuration of the liquid crystal display device. As shown in FIG. 4, the liquid crystal display device 20 of the present invention includes a liquid crystal cell 30, a first polarizing plate 40 and a second polarizing plate 50 sandwiching the liquid crystal cell 30, and a backlight 60.

The display mode of the liquid crystal cell 30 may be any display mode such as TN (Twisted Nematic), VA (Vistational Alignment), or IPS (In Plane Switching). The liquid crystal cell for mobile devices is preferably in the IPS mode, for example. The VA mode is preferable for liquid crystal cells for medium and large-sized applications.

The first polarizing plate 40 is disposed on the viewing side surface of the liquid crystal cell 30, and the first polarizer 41 and the protection disposed on the surface of the first polarizer 41 opposite to the liquid crystal cell side. It includes a film 43 (F1) and a protective film 45 (F2) arranged on the surface of the first polarizer 41 on the liquid crystal cell side.

The second polarizing plate 50 is disposed on the backlight side surface of the liquid crystal cell 30, and the second polarizer 51 and the protective film 53 disposed on the liquid crystal cell side surface of the second polarizer 51. (F3) and a protective film 55 (F4) arranged on the surface of the second polarizer 51 opposite to the liquid crystal cell.

The absorption axis of the first polarizer 41 and the absorption axis of the second polarizer 51 are preferably orthogonal to each other.

The protective film 45 (F2) can be the optical laminated film of the present invention. The easy-adhesion layer 48 of the optical laminated film and the first polarizer 41 are laminated directly or via an adhesive layer (not shown). The in-plane slow axis of the protective film 43 (F2) and the absorption axis of the first polarizer 41 may be substantially orthogonal to each other. The protective films 43 (F1), 53 (F3) and 55 (F4) can be, for example, the other films described above.

Although FIG. 4 shows an example in which the protective film 45 (F2) is the optical laminated film of the present invention, the invention is not limited to this, and the protective films 43 (F1), 45 (F2), 53 (F3) and 55 ( At least one of F4) can be the optical laminated film of the present invention. For example, when the protective film 43 (F1) is used as the optical laminated film of the present invention and functions as a λ/4 film, the in-plane slow axis of the optical laminated film of the present invention and the absorption axis of the first polarizer 41 are The angle formed may be 40 to 50° as described above. When the protective film 45 (F2) is used as the optical laminated film of the present invention to function as a retardation film for VA, the in-plane slow axis of the optical laminated film of the present invention and the absorption axis of the polarizer may be substantially orthogonal to each other. ..

As described above, in the optical laminated film of the present invention as the protective film 45 (F2), since the ultraviolet absorber and the antioxidant are unevenly distributed on the surface of the base material layer 11, the base material layer 11 and the easy adhesion layer 13 are formed. The adhesion unevenness between and is reduced. Furthermore, since the base layer 11 of the optical laminated film of the present invention contains a certain amount or more of residual solvent, the difference in force between the base layer 11 and the easy-adhesion layer 13 that tends to expand can be reduced, An axis shift between the absorption axis of the polarizer and the slow axis of the optical laminated film 10 can be suppressed. Thereby, the liquid crystal display device of the present invention can suppress optical unevenness under high temperature and high humidity while having good durability.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

1. Preparation of base film (base layer) 1) Material of base film <Synthesis of cycloolefin resin>
(Synthesis example 1)
Reaction in which 100 parts by mass of Exemplified Compound 11 of the general formula (A-1) as a cycloolefin monomer, 3.6 parts by mass of 1-hexene that is a molecular weight modifier, and 200 parts by mass of toluene were substituted with nitrogen. It was charged in a container and heated to 80°C. Thereto, and triethylaluminum _{((C 2 H 5) 3} Al) 0.17 parts by weight of a toluene solution of 1.5 mol / l as a polymerization catalyst, t-butanol - Le and modified tungsten hexachloride with methanol (WCl ₆ ), and 1.0 parts by mass of a WCl ₆ solution (concentration 0.05 mol/l) containing t-butanol:methanol:tungsten=0.35:0.3:1 (molar ratio), A ring-opening polymerization reaction was performed by heating and stirring at 80° C. for 3 hours to obtain a polymer solution. The polymerization conversion rate in this polymerization reaction was 96%.
4000 parts by mass of the obtained polymer solution was put into an autoclave, 0.48 parts by mass of RuHCl(CO)[P(C ₆ H ₅ ) ₃ ] ₃ was added to this polymer solution, the hydrogen gas pressure was 10 MPa, and the reaction was performed. The mixture was heated and stirred at a temperature of 160° C. for 3 hours to carry out a hydrogenation reaction.
After cooling the obtained reaction solution, the hydrogen gas was released, and the reaction solution was poured into a large amount of methanol to separate and collect a coagulated product. The collected coagulated product was dried to obtain cycloolefin resin 1.

(Synthesis examples 2 to 4)
The cycloolefin resins 2 to 4 were prepared in the same manner as in Synthesis Example 1 except that the drying temperature at the time of drying the separated coagulated product was changed as shown in Table 1 after the hydrogenation reaction solution was filtered and washed. Obtained.

紫外線吸収剤Ｂ：N,N',N''‐トリ‐ｍ‐トルイル‐１,３,５‐トリアジン‐２,４,６‐トリアミン
紫外線吸収剤Ｃ：CHIMASSORB 81 （下記式参照）

1-2) UV absorber UV absorber A: Tinuvin928 (2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3 -Tetramethylbutyl)phenol) (see formula below)

UV absorber B: N,N',N"-tri-m-toluyl-1,3,5-triazine-2,4,6-triamine UV absorber C: CHIMASSORB 81 (see the following formula)

1-3) Antioxidant Antioxidant: IRGANOX 1010 (see the formula below)

2) Production of base film <Production of base film 1>
(Preparation of liquid containing fine particles)
The components below were mixed by stirring with a dissolver for 50 minutes, and then dispersed with manton-goline. Furthermore, dispersion was performed with an attritor so that the particle size of the secondary particles would be a predetermined size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to obtain a fine particle added liquid.
Fine particles (Aerosil R812: manufactured by Nippon Aerosil Co., Ltd., primary average particle diameter: 7 nm, apparent specific gravity: 50 g/L): 4 parts by mass Methylene chloride: 96 parts by mass

(Preparation of dope solution)
Then, the following components were sufficiently dissolved while heating to obtain a dope solution.
Cycloolefin resin obtained in Synthesis Example 1: 1:100 parts by mass Ultraviolet absorber A: 8 parts by mass IRGANOX 1010 (antioxidant): 0.2 parts by mass Methylene chloride: 210 parts by mass Fine particle additive liquid: 3 parts by mass

(Preparation of substrate film by solution casting film forming method)
The obtained dope solution was kept at 40° C. and uniformly cast on a stainless belt which is an endless metal support kept at 40° C. The cast film was dried until the residual solvent amount became 80% by mass, and then peeled off from the stainless belt to obtain a film-shaped product. The obtained film-like material was dried at 40° C. until the residual solvent amount became 5% by mass, and then stretched in the width direction at a stretch ratio of 1.5 times. The obtained film-like material was further dried at 120° C. while being conveyed by a large number of rolls to obtain a base film 1 having a thickness of 20 μm and a width of 1.3 m.

<Production of base material films 2 to 5>
In the production of the base film 1, base films 2 to 5 were obtained in the same manner except that the solvent composition of the dope was changed as shown in Table 2.

<Production of Base Films 6-11>
In the production of the base film 3, base films 6 to 11 were obtained in the same manner except that the solvent composition of the dope and the drying temperature after stretching were changed as shown in Table 2.

<Production of substrate films 12 to 16>
In the production of the base film 3, base films 12 to 16 were obtained in the same manner except that the content of the ultraviolet absorber contained in the dope was changed as shown in Table 2.

<Production of base material films 17 to 19>
In the production of the base film 15, base films 17 to 19 were obtained in the same manner except that the type of cycloolefin resin contained in the dope was changed as shown in Table 2.

<Production of substrate films 20 to 22>
In the production of the base film 2, base films 20 to 22 were obtained in the same manner except that the kind and the content of the ultraviolet absorber contained in the dope were changed as shown in Table 2.

<Production of base film 23>
(Preparation of pellets)
100 parts by mass of the dried cycloolefin resin 1, 3 parts by mass of the ultraviolet absorber A and 0.2 parts by mass of IRGANOX 1010 (antioxidant) were mixed by a twin-screw extruder. The obtained mixture was put into a hopper connected to an extruder and melt-extruded with a single-screw extruder to obtain pellets.

Next, the obtained pellets are loaded into a double flight type 50 mm single screw extruder (ratio L/D=32 of effective screw length L and screw diameter D) in which a leaf disc-shaped polymer filter with openings of 3 μm is installed. Then, the molten resin was supplied to the die at an extruder outlet temperature of 280° C. and a rotation speed of a gear pump of the extruder of 10 rpm. Then, the molten resin was discharged from the die at 280° C., and cast on a cooling roll whose temperature was adjusted to 150° C. to obtain a base film 23. The air gap amount was 50 mm.

<Preparation of substrate film 24>
A base film 24 was obtained in the same manner as in the preparation of the base film 20, except that stretching was not performed.

<Production of base film 25>
A base film 25 was obtained in the same manner as in the preparation of the base film 2, except that the ultraviolet absorber was not added and the amount of the cycloolefin resin 1 added was 108 parts by mass.

The content distribution (Mc/Ms) of the ultraviolet absorber and the antioxidant and the amount of residual solvent of the obtained base film were measured by the following methods, respectively.

(Mc/Ms)
The Mc/Ms of the base film was measured by the following procedure. That is,
1) The base film was cut with a microtome to obtain a cut surface perpendicular to the surface of the base film.
2) The surface distribution image (IR image image) of the measurement object on the cut surface of the obtained base film was measured by the ATR method using Nicolet 380 manufactured by Thermo Fisher Scientific.
(Measurement condition)
Each measurement area: 30 μm×30 μm (area including the surface and inside of the base film)
3) In the measurement region, the peak of the ultraviolet absorber or the antioxidant to be measured (peak to be measured) was extracted, the content was quantified from its absorbance, and a visualized IR image image was obtained.
In the measurement area, the integrated value As1 of the absorbance of the peak to be measured in the area from one surface of the base film to the position of 2 μm in the thickness direction, from the other surface of the base film to the position of 2 μm in the thickness direction The integrated value As2 of the absorbance of the measurement target peak in the region of and the integrated value As of the absorbance of the measurement target peak in the region from the center of the thickness direction of the base film to the position of ±2 μm in the thickness direction are measured, and the ratio thereof Ac/As1 and Ac/As2 were calculated, respectively. Of these ratios, the smaller value was defined as "Mc/Ms".

(Qualitative and quantitative determination of residual solvent)
The qualitative and quantitative determination of the residual solvent in the obtained base film was performed by headspace gas chromatography. In headspace gas chromatography, the sample is sealed in a container and heated, and the gas in the container is quickly injected into the gas chromatograph when the container is filled with volatile components, and the compound is identified by mass spectrometry. While quantifying the volatile components. The volatile component was quantified by preparing a calibration curve in advance using a sample having a known concentration, and comparing the peak area of the volatile component obtained by the measurement with the calibration curve.
(Measurement condition)
Headspace device: HP7694 Head Space Sampler (manufactured by Hewlett Packard)
Temperature conditions: Transfer line 200℃, loop temperature 200℃
Sample amount: 0.8 g/20 ml vial GC: HP5890 (manufactured by Hewlett Packard)
MS: HP5971 (manufactured by Hewlett Packard)
Column: HP-624 (30m x inner diameter 0.25mm)
Oven temperature: initial temperature 40°C (holding time 3 minutes), temperature rising rate 10°C/minute, ultimate temperature 200°C (holding time 5 minutes)
Measurement mode: SIM (select ion monitor) mode

Table 2 shows the production conditions and evaluation results of the base material films 1 to 25. In the table, MC indicates methylene chloride, Et indicates ethanol, and Me indicates methanol.

It was confirmed from the IR image images that all the base films other than the base films 4, 5, and 23 had the ultraviolet absorber or the antioxidant unevenly distributed on both sides or one side of the base film. Then, as shown in Table 2, by adjusting the solvent composition of the dope in the manufacturing process of the base film and the residual solvent amount of the film material before drying, the Mc/Ms of the base film obtained is less than 1. It is shown that it can be adjusted to (contrast of base material films 1 to 5). Specifically, it is shown that when the content ratio of methylene chloride having a low boiling point increases, the amount of residual solvent of the film material before drying tends to decrease, and Mc/Ms of the base film tends to be kept at a certain level or less.

It is shown that by lowering the drying temperature of the film-like material in the process of manufacturing the base film, the amount of residual solvent in the obtained base film can be set to a certain level or more (contrast with base films 6 to 11).

It is shown that the residual toluene amount of the obtained base film can be set to a certain amount or more by comparing the cycloolefin-based resin synthesis condition (vacuum drying temperature) (contrast between base films 15 and 17 to 19).

2. Preparation of Optical Laminated Film 1) Material of Easy Adhesion Layer <Preparation of Composition 1 for Easy Adhesion Layer>
KBM-603 (amino type silane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd. was dissolved in 1-methoxy-2-propanol to obtain a composition 1 for an easy-adhesion layer having a concentration of 10% by weight.

<Preparation of Composition 2 for Easy Adhesion Layer>
Sumiraz resin 650 (polyamide epoxy resin) manufactured by Taoka Chemical Industry Co., Ltd. was dissolved in pure water to obtain a composition 2 for easy adhesion layer having a concentration of 10% by weight.

<Preparation of Composition 3 for Easy Adhesion Layer>
Superflex 210 (water-based urethane resin) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., and adipic acid as a cross-linking agent and an epoxy resin are dissolved in pure water to form a composition for an easily adhesive layer having a concentration of 10% by mass of Superflex 210. Item 3 was obtained.

2) Production of optical laminated film <Production of optical laminated films 1 to 16 and 28>
Corona discharge treatment was applied to the surface forming the area S of the base film shown in Table 3 (the surface having the value of Mc/Ms in Table 2). The electron irradiation dose in the corona discharge was 500 W/m ² /min. The composition 1 for easy-adhesion layer prepared above was applied on the corona-treated surface of the obtained substrate film by a bar coater so that the thickness after drying was 0.8 μm, and then dried at 80° C. for 5 minutes. To form an easily adhesive layer. Thereby, optical laminated films 1 to 16 and 28 including the base film and the easy-adhesion layer were obtained.

<Production of Optical Laminated Films 17 to 18>
After coating the composition for easy-adhesion layer shown in Table 3 on the base film 15, it was dried at 100° C. for 10 minutes to form an easy-adhesion layer to obtain optical laminated films 17 to 18.

<Production of Optical Laminated Film 19>
In the production of the optical laminated film 15, an optical laminated film 19 was obtained in the same manner except that the easy adhesion layer was not formed.

<Production of Optical Laminated Films 20 to 27>
The composition 2 for easy-adhesion layer produced above was applied onto the base film shown in Table 3, and then dried at 100° C. for 10 minutes to form an easy-adhesion layer, thereby obtaining optical laminated films 20 to 27. It was

The following method evaluated the adhesiveness with the polarizer of the obtained optical laminated film.

(Adhesiveness with polarizer)
1) Production of Polarizer A polyvinyl alcohol film having a thickness of 25 μm was swollen with water at 35° C. The obtained film was dipped in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and further dipped in an aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water at 45°C. .. The obtained film was uniaxially stretched under the conditions of a stretching temperature of 55° C. and a stretching ratio of 5 times. The uniaxially stretched film was washed with water and then dried to obtain a polarizer having a thickness of 7 μm.

2) Preparation of sample for evaluation On the easy-adhesion layer of the obtained optical laminated film, a 3% by mass aqueous solution of polyvinyl alcohol (PVA-117H manufactured by Kuraray), which is an aqueous adhesive, was applied, and then the above-prepared polarizer was attached. I matched it. The lamination was performed so that the slow axis of the optical laminated film and the absorption axis of the polarizer were orthogonal to each other. The obtained laminate was dried at 60° C. for 5 minutes to obtain a sample for evaluation.

The obtained evaluation sample was left for 24 hours in an environment of 23° C. and 55% relative humidity. After that, when the adhesive surface between the polarizer and the optical laminated film of the evaluation sample was peeled off by hand, the presence or absence of material destruction in the optical laminated film and the degree of peeling were visually observed, and adhered according to the following criteria. The sex was evaluated. It was judged that there was no problem in practical use if it was ◯ or more.
⊚: Does not peel off ◯: There is no problem with the adhesive force between the optical laminated film and the polarizer, and when the optical laminated film is tried to be peeled off, a material (a part of at least one end of the optical laminated film and the polarizer ( Substrate) Destruction occurs Δ: Part of the interface between the optical laminated film and the polarizer is peeled off ×: All of the interface between the polarizing plate protective film and the polarizing film is peeled off

Table 3 shows the evaluation results of the optical laminated films 1-27.

As shown in Table 3, the optical laminated film in which the ultraviolet absorber and the antioxidant were unevenly distributed on the surface in the base material layer (Mc/Ms was less than 1) was used as the ultraviolet absorber in the base material layer. It is shown that the adhesiveness to the polarizer is higher than that of the optical laminated film in which the antioxidant is not unevenly distributed on the surface (Mc/Ms=1) (contrast of optical laminated films 1 to 5 and 28).

Further, since the optical laminated film including the melt-formed base material layer has low adhesiveness with the easy-adhesion layer, it can be seen that the adhesiveness with the polarizer is also low (comparison between optical laminated films 26 and 15). .. Further, it is shown that the optical laminated film not provided with the easy-adhesion layer has low adhesiveness to the polarizer (comparison between optical laminated films 15 and 17 to 19).

3. Manufacture of liquid crystal display device <Manufacture of liquid crystal display device 1>
As the polarizer, the polarizer used in the evaluation of the “adhesiveness with the polarizer” described above was prepared. As the protective film F1, Konica Minolta Tack KC6UA (manufactured by Konica Minolta) was prepared. As the protective film F2, the optical laminated film 1 prepared above was prepared.

Then, the surface of KC6UA was subjected to alkali saponification treatment under the following conditions. Specifically, KC6UA was immersed in a 1.5N sodium hydroxide aqueous solution at 55°C for 2 minutes, washed in a water-washing bath at room temperature, and neutralized with 0.1N sulfuric acid at 30°C. The obtained KC6UA was washed again in a water-washing bath at room temperature and then dried with warm air at 100°C.

The alkali-saponified surface-treated KC6UA, the polarizer, and the optical laminated film 1 prepared above were bonded together via a 3% by mass aqueous solution of polyvinyl alcohol (PVA-117H manufactured by Kuraray), which is an aqueous adhesive, and KC6UA/polarizer/optical A laminate of the laminated film 1 was obtained. The lamination is performed so that one surface of the polarizer is in contact with the saponified surface of KC6UA and the other surface is in contact with the easy-adhesion layer of the optical laminated film 1, and the in-plane slow axis of the optical laminated film 1 and the polarized light are polarized. It was performed so that the absorption axis of the child was orthogonal. The obtained laminate was dried to obtain polarizing plate 1.

(Production of liquid crystal display device)
As a liquid crystal display device, a VA type Sony liquid crystal television (model number: BRAVIA KJ-43X8500C) was prepared. The polarizing plate on the viewing side was peeled off from this device, and the polarizing plate 1 prepared above was attached to the viewing side surface of the liquid crystal cell to obtain a liquid crystal display device 1.
The polarizing plate 1 is attached before the optical laminated film 1 (protective film F2) is on the liquid crystal cell side, the absorption axis of the polarizer and the slow axis of the optical laminated film 1 are orthogonal to each other, and before peeling from the liquid crystal cell. It was performed so as to coincide with the absorption axis of the viewing side polarizing plate.

<Production of liquid crystal display devices 2 to 27>
In the production of the liquid crystal display device 1, liquid crystal display devices 2 to 27 were obtained in the same manner except that the kind of the protective film F2 of the polarizing plate was changed as shown in Table 4.

<Production of liquid crystal display devices 28 to 29>
In the manufacture of the liquid crystal display device 1, liquid crystal display devices 28 to 29 were obtained in the same manner except that the types of the protective films F1 and F2 of the polarizing plate were changed as shown in Table 4.

The optical unevenness of the obtained liquid crystal display device was visually observed and evaluated based on the following criteria. The optical unevenness is a phenomenon in which whitish areas such as light leaks are sparsely formed on the entire screen or the four corners of the screen when black is displayed. If it was ◯ or more, it was judged that there was no problem in practical use ◎: No unevenness was observed at all.
◯: Almost no unevenness is observed (total area of unevenness is 5% or less of the area of the entire screen).
Δ: Some slight unevenness is observed depending on the visual angle (the total area of unevenness is more than 5% of the area of the entire screen).
X: Strong unevenness is clearly observed on the screen.

Table 4 shows the evaluation results of the liquid crystal display devices 1 to 29.

As shown in Table 4, the optical laminated films 1 to 3, 7 to 10, 12 to 18 and 20 in which the Mc/Ms of the base film is less than 1 and the residual solvent amount of the base film is a certain amount or more. Nos. 25 and 27 to 29 show that optical unevenness can be suppressed.

On the other hand, in the optical laminated films 4 and 5 in which Mc/Ms of the base film is 1 or more, optical unevenness caused by uneven adhesion occurs, and the optical laminated film 6 in which the residual solvent amount of the base film is too small is It is suggested that the optical unevenness caused by the axis misalignment occurs. Further, the optical laminated film 19 having no easy-adhesion layer has optical unevenness caused by adhesion unevenness, and the optical laminated film 26 obtained by melt-forming the base film has optical unevenness caused by axial misalignment. It is suggested to do.

<Production of liquid crystal display device 30>
(Production of Polarizing Plate 29)
A polarizing plate 29 was obtained in the same manner as described above, except that Konica Minolta Tack KC6UA (manufactured by Konica Minolta) was used as the protective film F1 and the optical laminated film 27 prepared above was used as the protective film F2.

(Production of liquid crystal display device)
As a liquid crystal display device, a liquid crystal television (model number: 43UF6900) manufactured by LG Electronics of the IPS system was prepared. The polarizing plate on the viewing side was peeled off from this apparatus, and the polarizing plate 29 prepared above was attached to the viewing side surface of the liquid crystal cell to obtain a liquid crystal display device 30.
The polarizing plate 29 is attached before the optical laminated film 27 (protective film F2) is on the liquid crystal cell side, the absorption axis of the polarizer and the slow axis of the optical laminated film 27 are orthogonal to each other, and before peeling from the liquid crystal cell. It was performed so as to coincide with the absorption axis of the viewing side polarizing plate.

<Production of liquid crystal display devices 31 to 33>
In the production of the liquid crystal display device 30, liquid crystal display devices 31 to 33 were obtained in the same manner except that the types of the protective films F1 and F2 of the polarizing plate were changed as shown in Table 5.

The optical unevenness of the obtained liquid crystal display device was visually observed and evaluated by the same method as described above. It was judged that there was no problem in practical use if it was ◯ or more.

Table 5 shows the evaluation results of the liquid crystal display devices 30 to 33.

As shown in Table 5, the liquid crystal display devices 30 and 31 using the optical laminated film 27 in which Mc/Ms in the base film is less than 1 and the residual solvent amount of the base film is not less than a certain level are It is shown that unevenness can be suppressed.

On the other hand, it is suggested that the liquid crystal display devices 32 and 33 using the optical laminated film 26 obtained by melt-forming the base material film cause optical unevenness due to axial misalignment.

ADVANTAGE OF THE INVENTION According to this invention, the optical laminated film which has favorable durability and can suppress the optical unevenness of a liquid crystal display device under high temperature and high humidity can be provided.

10 Optical Laminated Film 11 Base Layer 13, 48 Easy Adhesive Layer 20 Liquid Crystal Display Device 30 Liquid Crystal Cell 40 First Polarizing Plate 41 First Polarizer 43 Protective Film (F1)
45 Protective film (F2)
50 Second Polarizing Plate 51 Second Polarizer 53 Protective Film (F3)
55 Protective film (F4)
60 backlight

Claims (11)

Cycloolefin resin, a base material layer containing at least one of an ultraviolet absorber and an antioxidant, an amide resin, a urethane resin or an easy-adhesion layer containing a silane coupling agent,
In the cut surface perpendicular to the surface of the base material layer, the ultraviolet absorber and the antioxidant in the region S from the surface of the base material layer on which the easy-adhesion layer is arranged to a position of 0.1 t in the thickness direction. When Ms is the total content of the ultraviolet absorber and the antioxidant in the region C from the center of the base material layer to the position of ±0.1 t in the thickness direction (provided that the above The thickness of the base material layer is t), Mc/Ms is 0.01 or more and 0.8 or less , and the residual solvent amount of the base material layer is 100 ppm or more and 2000 ppm or less,
Optical laminated film. The content of the ultraviolet absorber in the base material layer is 0.5 to 5 mass% with respect to the cycloolefin resin.
The optical laminated film according to claim 1. The content of the antioxidant in the base material layer is 0.5 to 5 mass% with respect to the cycloolefin resin.
The optical laminated film according to claim 1. The amide resin is a water-soluble polyamide epoxy resin,
The optical laminated film according to claim 1. The base material layer contains 100 to 300 ppm of toluene as the residual solvent.
The optical laminated film according to claim 1. The Mc/Ms is 0.7 or less,
The optical laminated film according to claim 1. An optical laminated film according to any one of claims 1 to 6, and a polarizer arranged on the surface of the easily adhesive layer side thereof.
Polarizer. A liquid crystal display device including a first polarizing plate, a liquid crystal cell, a second polarizing plate, and a backlight in this order,
The first polarizing plate includes a first polarizer, a protective film F1 disposed on a surface of the first polarizer opposite to the liquid crystal cell, and the liquid crystal cell of the first polarizer. Including a protective film F2 arranged on the side surface,
The second polarizing plate is opposite to the second polarizer, the protective film F3 disposed on the liquid crystal cell side surface of the second polarizer, and the liquid crystal cell of the second polarizer. And a protective film F4 arranged on the side surface,
At least one of the protective films F1 and F2 is the optical laminated film according to any one of claims 1 to 6, and the first polarizer is the surface of the optical laminated film on the easy adhesive layer side. And/or at least one of the protective films F3 and F4 is the optical laminated film according to any one of claims 1 to 6, and the second polarizer is the optical layer. It is arranged on the surface of the laminated film on the side of the easily adhesive layer,
Liquid crystal display device. At least one of the protective films F1 and F2 is the optical laminated film according to any one of claims 1 to 6, and the first polarizer is the surface of the optical laminated film on the easy adhesive layer side. Is located in the
The liquid crystal display device according to claim 8. A cycloolefin resin, saw-containing and at least one UV absorber and an antioxidant, wherein are unevenly distributed ultraviolet absorbers and antioxidants surface and the substrate remaining solvent amount is 100ppm or more 2000ppm or less Obtaining a layer,
A step of subjecting the surface of the base material layer where the ultraviolet absorber and the antioxidant are unevenly distributed to a hydrophilic treatment,
A composition for an easy-adhesion layer containing an amide resin, a urethane resin or a silane coupling agent is applied to the surface of the base material layer that has been subjected to the hydrophilic treatment, and then dried or cured to form an easy-adhesion layer. The process of
Have
The step of obtaining the substrate layer,
1) a step of dissolving the cycloolefin resin and at least one of the ultraviolet absorber and the antioxidant in a solvent to obtain a dope,
2) a step of casting the dope on a support and then peeling it off to obtain a film-like material,
3) a step of drying the peeled film material
Have
In the step 2), the residual solvent amount of the film-like material at the time of peeling is 10% by mass or less.
Method for producing optical laminated film. In the cut surface perpendicular to the surface of the base material layer, the total content of the ultraviolet absorber and the antioxidant in the region S from at least one surface of the base material layer to the position of 0.1 t in the thickness direction is determined. Ms, when the total content of the ultraviolet absorber and the antioxidant in the region C from the center of the base material layer to the position of ±0.1 t in the thickness direction is Mc (however, the thickness of the base material layer is Is defined as t), and Mc/Ms is 0.01 or more and 0.8 or less,
The method for producing the optical laminated film according to claim 10 .

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