JP2015041529A - Film for transparent electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for a transparent electrode which includes an organic easily adhesive layer, suppresses an interference spot in a higher degree, prevents the interference spot from being viewed even when being viewed through a pair of polarized sunglasses, and also has excellent adhesion.SOLUTION: A film has a polyester film and an easily adhesive layer provided on at least one face thereof. The polyester film has an in-plane retardation of 7,000 nm or more and has a thickness of 5-250 μm. The easily adhesive layer contains a binder component formed from a thermoplastic resin as a main component, and has a wetting index of the surface thereof of 60 mN/m or more.

Description

  The present invention relates to a transparent electrode film. In particular, it is related with the film for transparent electrodes used suitably as a base material of the transparent electrode of a touchscreen.

  As a base material used for a transparent electrode, studies for replacing a glass plate with a plastic film have been made for a long time in order to reduce weight and impart flexibility. However, in such replacement, there is a problem that the surface smoothness is impaired, and when used in a liquid crystal display device, interference spots easily occur. Here, it is known that the surface smoothness is smoothed by providing a hard coat layer on the surface. However, if it does so, the problem about the adhesiveness of a base material and the layer formed on it will arise.

For such problems, Patent Documents 1 and 2 provide a thin film made of silicon oxide or silicon aluminum composite oxide on a uniaxially stretched polyethylene terephthalate film having a retardation value of 5000 nm or more, and a cured resin layer thereon. An electrode substrate on which is formed has been reported.
In addition, the base material of the transparent electrode is often used to prevent deterioration due to ultraviolet rays from sunlight or ultraviolet rays from a liquid crystal backlight source (particularly in mobile devices used outdoors, to prevent deterioration of members due to external light). Ultraviolet absorbing ability is required. As an ultraviolet absorber used for an optical polyester film, for example, an ultraviolet absorber as disclosed in Patent Document 3 has been reported.

Japanese Patent Laid-Open No. 10-10558 JP-A-10-62776 JP 2003-191390 A

In recent years, the demand for interference spot suppression and adhesion has become even stronger. In particular, regarding the demand for suppression of interference spots, an increasing number of mobile devices are used outdoors, and there is an opportunity to view the liquid crystal display device while wearing polarized sunglasses.
In addition to the problem that the inorganic easy adhesive layer itself is hard and easy to be scratched, the inorganic easy adhesive layer for improving the adhesion is low in flexibility, so it can be pressed with a pen or finger like a touch panel. It is not suitable as a transparent electrode for applications requiring moderate flexibility.
Therefore, the present invention provides a transparent electrode film that includes an organic easy-adhesion layer, suppresses interference spots to a higher degree, makes it difficult to see interference spots even when viewed through polarized sunglasses, and has excellent adhesion. For the purpose.

Furthermore, as described above, a method of adding an ultraviolet absorber to the film is conceivable for imparting ultraviolet absorbing ability. However, the ultraviolet absorber internally added to the film generally tends to bleed out. Such a problem becomes more conspicuous particularly when the film is a uniaxially oriented polyester film because the oriented crystal structure is less than that of the biaxially oriented polyester film. If the ultraviolet absorbent bleeds out, it will lead to film whitening and process contamination.
Therefore, the present invention provides a transparent electrode film in which bleeding out of an ultraviolet absorber is suppressed while having a degree of molecular orientation that can suitably suppress interference spots when used as a substrate for a transparent electrode. Is a desirable purpose.

（ただし、上記一般式（１）において、Ａｒはｎ価のビフェニル残基を表す。また、該ビフェニル残基は置換基を有していてもよい。Ａｒに結合している環は、任意の位置に二重結合を有していてもよい。Ｘａ、Ｘｂ、Ｘｃは、互いに独立してヘテロ原子を表す。またＸａ、Ｘｂ、Ｘｃは、置換基を有していてもよい。Ｒは１価の炭化水素基を表す。ｍは０〜４の整数を表す。ｎは１〜４の整数を表す。）
５．上記易接着層とは反対側の面にハードコート層を有する、上記１〜４のいずれか１項に記載の透明電極用フィルム。
６．上記１〜５に記載の透明電極用フィルムの上記易接着層とは反対側の面、もしくは、上記易接着層とは反対側の面にハードコート層を有する場合は該ハードコート層の上に透明導電層を設けた透明電極。
７．上記易接着層の上にポリビニルアルコールからなる偏光子を有する、上記６に記載の透明電極。
８．液晶表示装置と共に用いられるタッチパネル用である、上記６または７に記載の透明電極。 The present invention employs the following configuration in order to solve the above problems.
1. A film having a polyester film and an easy adhesion layer provided on one side thereof,
The in-plane retardation of the polyester film is 7000 nm or more, the thickness is 5 to 250 μm,
The easy-adhesion layer contains a binder component composed of a thermoplastic resin as a main component, and the surface wetting index is 60 mN / m or more.
Transparent electrode film.
2. 2. The transparent material according to 1 above, wherein the binder component of the easy-adhesion layer comprises 40 to 90% by mass of a copolyester based on the mass of the binder component and 10 to 60% by mass of polyvinyl alcohol based on the mass of the binder component. Electrode film.
3. The film for transparent electrodes according to 1 or 2 above, wherein the polyester film contains 0.1 to 10% by mass of an ultraviolet absorber based on the mass of the polyester film.
4). 4. The transparent electrode film as described in 3 above, wherein the ultraviolet absorber is an ultraviolet absorber represented by the following general formula (1).

(However, in the above general formula (1), Ar represents an n-valent biphenyl residue. The biphenyl residue may have a substituent. The ring bonded to Ar may be any arbitrary ring. Xa, Xb, and Xc each independently represent a hetero atom, and Xa, Xb, and Xc may have a substituent, and R is 1. Represents a valent hydrocarbon group, m represents an integer of 0 to 4, and n represents an integer of 1 to 4.)
5. 5. The transparent electrode film according to any one of 1 to 4, which has a hard coat layer on the surface opposite to the easy-adhesion layer.
6). On the surface of the transparent electrode film described in the above 1 to 5 on the side opposite to the easy-adhesive layer, or on the surface opposite to the easy-adhesive layer, a hard coat layer is provided on the hard coat layer. A transparent electrode provided with a transparent conductive layer.
7). 7. The transparent electrode according to 6 above, having a polarizer made of polyvinyl alcohol on the easy-adhesion layer.
8). 8. The transparent electrode as described in 6 or 7 above, which is for a touch panel used with a liquid crystal display device.

According to the present invention, a transparent electrode film having an organic easy-adhesion layer, more highly suppressing interference spots, hardly seeing interference spots even when viewed through polarized sunglasses, and having excellent adhesion is obtained. be able to.
Moreover, according to a desirable aspect of the present invention, a transparent electrode in which bleeding out of an ultraviolet absorber is suppressed while having a molecular orientation that can suitably suppress interference spots when used as a substrate of a transparent electrode. Films can be provided.

  Therefore, the film of the present invention can be suitably used as a transparent electrode particularly used for optical applications. Especially, it can use suitably as a transparent electrode used for a touch panel, and can show a function more effectively by adopting the film of the present invention as a substrate of a transparent electrode of a touch panel used with a liquid crystal display device. .

  The film of this invention has an easily bonding layer in the at least single side | surface of the polyester film whose in-plane retardation is 7000 nm or more. Hereafter, each structural component which comprises the film of this invention is demonstrated.

[Polyester film]
The polyester film in the present invention is formed from polyester.

(polyester)
Such polyester comprises a dicarboxylic acid component and a glycol component. As the dicarboxylic acid component, an aromatic dicarboxylic acid component is preferable from the viewpoint that a preferable degree of molecular orientation is easily obtained and from the viewpoint of excellent mechanical characteristics and thermal characteristics. Preferred examples of the aromatic dicarboxylic acid component include components derived from phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. Moreover, as a glycol component, the component derived from ethylene glycol, diethylene glycol, neopentyl glycol, and polyalkylene glycol can be illustrated preferably. Among these, as the polyester, polyethylene terephthalate is preferable from the viewpoints of heat resistance and optical properties. Such polyethylene terephthalate may be a copolymerized polyethylene terephthalate containing a copolymer component as long as the object of the present invention is not impaired.

(Retardation)
The polyester film in the present invention has an in-plane retardation of 7000 nm or more. Here, the retardation is expressed as: | nTD−nMD | × film thickness (nm) from the maximum refractive index (nTD) in the film plane and the refractive index (nMD) in a direction perpendicular to the direction showing the maximum refractive index. This is the required value.
When the in-plane retardation of the polyester film is in the above range, a change in the vibration direction of linearly polarized light emitted from the polarizer can be suppressed. Furthermore, interference fringes generated when light from the outside is reflected can be suppressed. From this viewpoint, the in-plane retardation is preferably 7500 nm or more, more preferably 7800 nm or more, still more preferably 8000 nm or more, and particularly preferably 8500 nm or more. On the other hand, the upper limit of retardation is not particularly limited from the viewpoint of suppressing the vibration direction change of linearly polarized light, but considering that the above-described retardation mode is achieved by stretching orientation of the polyester film, it is a film that attempts to obtain an excessively high retardation. There is a tendency that breakage tends to occur or the obtained polyester film becomes brittle. From this viewpoint, the upper limit of the in-plane retardation is preferably 30000 nm.

(Film thickness)
The thickness of the polyester film in the present invention is 5 from the viewpoint of providing a strength and stiffness suitable as a transparent electrode film, particularly as a transparent electrode film used in a touch panel, easily obtaining a suitable retardation, and excellent transparency. ˜250 μm. If it is too thin, suitable retardation tends to be difficult to obtain, and strength and stiffness tend to decrease. Moreover, it is inferior in handleability and tends to be difficult to bond with other optical members and to be incorporated into an apparatus. Furthermore, film formation tends to be difficult. On the other hand, if it is too thick, the product mass tends to increase due to the increase in mass of the polyester film. Also, it tends to be inferior in transparency. From this viewpoint, the thickness is preferably 10 to 125 μm, more preferably 10 to 100 μm, and still more preferably 25 to 100 μm.

[Ultraviolet absorber]
It is preferable that the polyester film in this invention contains a 0.1-10 mass% ultraviolet absorber based on the mass of a polyester film. Examples include benzophenone-based UV absorbers, hindered amine-based UV absorbers, benzoate-based UV absorbers, and triazine-based UV absorbers, and UV absorbers represented by the following general formula (1) are preferred.

（ただし、上記一般式（１）において、Ａｒはｎ価のビフェニル残基を表す。また、該ビフェニル残基は置換基を有していてもよい。Ａｒに結合している環は、任意の位置に二重結合を有していてもよい。Ｘａ、Ｘｂ、Ｘｃは、互いに独立してヘテロ原子を表す。またＸａ、Ｘｂ、Ｘｃは、置換基を有していてもよい。Ｒは１価の炭化水素基を表す。ｍは０〜４の整数を表す。ｎは１〜４の整数を表す。）

(However, in the above general formula (1), Ar represents an n-valent biphenyl residue. The biphenyl residue may have a substituent. The ring bonded to Ar may be any arbitrary ring. Xa, Xb, and Xc each independently represent a hetero atom, and Xa, Xb, and Xc may have a substituent, and R is 1. Represents a valent hydrocarbon group, m represents an integer of 0 to 4, and n represents an integer of 1 to 4.)

By adopting the ultraviolet absorber having such a structure, bleeding out from the film is suppressed.
In the general formula (1), Ar represents a monovalent to tetravalent biphenyl residue. In the present invention, such a structure is essential, and the effect of suppressing bleed out is greatly achieved by such a structure. Ar is preferably a divalent to tetravalent group, more preferably a divalent group, from the viewpoints of cost, ease of obtaining a compound, and the like.

  Ar is a 1 to 4 valent biphenyl residue obtained by removing 1 to 4 hydrogen atoms from the biphenyl structure. The position where the hydrogen atom is removed from the biphenyl structure may be any location. In the case of being divalent, for example, 3, 3 'position, 4, 4' position and the like are mentioned. In the case of being trivalent, for example, the 3, 5, 3 'positions and the like can be mentioned. In the case of tetravalent, for example, 3, 5, 3 ', 5' positions and the like can be mentioned.

The biphenyl residue Ar may have a substituent. A monovalent substituent is mentioned as a substituent. Examples of the monovalent substituent (hereinafter referred to as R1) include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a linear or branched alkyl group having 1 to 20 carbon atoms (for example, methyl, Ethyl), an aryl group having 6 to 20 carbon atoms (for example, phenyl, naphthyl), a cyano group, a carboxyl group, an alkoxycarbonyl group (for example, methoxycarbonyl), an aryloxycarbonyl group (for example, phenoxycarbonyl), a substituted or unsubstituted carbamoyl group (Eg carbamoyl, N-phenylcarbamoyl, N, N-dimethylcarbamoyl), alkylcarbonyl group (eg acetyl), arylcarbonyl group (eg benzoyl), nitro group, substituted or unsubstituted amino group (eg amino, dimethylamino, Anilino), acylamino group (eg ace Amide, ethoxycarbonylamino), sulfonamide group (eg methanesulfonamide), imide group (eg succinimide, phthalimide), imino group (eg benzylideneamino), hydroxy group, alkoxy group having 1 to 20 carbon atoms (eg methoxy), Aryloxy groups (eg phenoxy), acyloxy groups (eg acetoxy), alkylsulfonyloxy groups (eg methanesulfonyloxy), arylsulfonyloxy groups (eg benzenesulfonyloxy), sulfo groups, substituted or unsubstituted sulfamoyl groups (eg sulfamoyl) N-phenylsulfamoyl), alkylthio group (for example, methylthio), arylthio group (for example, phenylthio), alkylsulfonyl group (for example, methanesulfonyl), arylsulfonyl group Group (e.g., benzenesulfonyl), and the like Hajime Tamaki having 6 to 20 carbon atoms (e.g. pyridyl, morpholino). Further, the substituent may be further substituted, and when there are a plurality of substituents, they may be the same or different. At that time, examples of the substituent include the monovalent substituent R1 described above. Moreover, you may combine with substituents and may form a ring.
Preferred examples of the substituent include an alkyl group, an alkoxy group, and an aryl group. An alkyl group and an aryl group are more preferable, and an alkyl group is particularly preferable.

  In the general formula (1), Xa, Xb and Xc each independently represent a hetero atom. Examples of the hetero atom include a boron atom, a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom, a sulfur atom, a selenium atom, and a tellurium atom. A hetero atom is preferably a nitrogen atom, an oxygen atom, or a sulfur atom. More preferably, they are a nitrogen atom and an oxygen atom. By selecting these heteroatoms, the effect of improving the ultraviolet absorption ability can be enhanced, the wavelength characteristics are excellent, the visible light region has a high transmittance, and the ultraviolet light region has a high absorption rate. This makes it possible to achieve compatible characteristics. Further, the stability and heat resistance of the ultraviolet absorber can be increased, and the production is easy. Xa, Xb and Xc may have a substituent. For example, when a nitrogen atom is selected as Xa and the bond between carbon bonded to Ar and Xa is a single bond, and a nitrogen atom is selected as Xb and carbon bonded to Ar and Xb When the bond between these is a single bond, or when a nitrogen atom is selected as Xc, the nitrogen atom appropriately has a substituent. Examples of the substituent include the examples of the monovalent substituent R1 described above.

The ring bonded to Ar including Xa, Xb and Xc may have a double bond at an arbitrary position. For example, when a nitrogen atom is selected as Xa, a double bond may be formed between carbon bonded to Ar and Xa. When a nitrogen atom is selected as Xb, a double bond may be formed between Xb and the carbon bonded to Ar.
A particularly preferred embodiment of Xa, Xb and Xc is an embodiment in which Xa is a nitrogen atom, a carbon and Xa bonded to Ar is a double bond, and Xb and Xc are oxygen atoms. As a result, the ultraviolet absorbing ability, wavelength characteristics, stability of the ultraviolet absorbent, and heat resistance can be further increased.

  In the general formula (1), R represents a monovalent hydrocarbon group. Such a hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, may contain a branched structure, or may contain a cyclic structure. Further, it may be a saturated hydrocarbon group or may have an unsaturated bond. Furthermore, you may have a substituent.

  The hydrocarbon group is preferably a hydrocarbon group having 1 to 20 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, from the viewpoint of the stability of the ultraviolet absorber. Saturated and chained aliphatic hydrocarbon groups are preferred. The number of carbon atoms is more preferably 1 to 4, and a methyl group, an ethyl group, a 1,2-propyl group, a 1,3-propyl group, a 1,4-butyl group, and a 1,6-hexyl group are preferable. Furthermore, as for carbon number, 1-2 are more preferable, and a methyl group and an ethyl group are especially preferable.

In the general formula (1), m represents an integer of 0 to 4. From the viewpoint of the absorption wavelength and the stability of the ultraviolet absorber, m is preferably 0 to 2, more preferably 0 to 1, and particularly preferably 0.
In the general formula (1), n represents an integer of 1 to 4. From the viewpoint of enhancing the effect of improving the ultraviolet absorbing ability, and the stability of the ultraviolet absorber and the ease of production, etc., n is preferably 1 to 3, more preferably 1 to 2, and particularly preferably 2. It is. When n is small, it tends to be sublimated easily. When n is large, synthesis tends to be difficult, and light in the visible light region tends to be absorbed, and transmittance tends to deteriorate and hue deteriorates.

(Ultraviolet absorber represented by the general formula (2))
Further, the ultraviolet absorber represented by the general formula (1) is preferably an ultraviolet absorber represented by the following general formula (2). By adopting such a configuration, the ultraviolet absorbing agent represented by the general formula (1) is further excellent in ultraviolet absorbing ability while maintaining the bleed-out suppressing effect or more excellent. Can be. Further, the stability as a compound is improved, and the ultraviolet absorbing ability can be maintained over a long period of time. Furthermore, the synthesis is easy, and the cost and productivity are excellent.

（ただし、上記一般式（２）において、Ａｒはｎ価のビフェニル残基を表す。また、該ビフェニル残基は置換基を有していてもよい。Ｒは１価の炭化水素基を表す。ｍは０〜４の整数を表す。ｎは１〜４の整数を表す。）

(However, in the general formula (2), Ar represents an n-valent biphenyl residue. The biphenyl residue may have a substituent. R represents a monovalent hydrocarbon group.) m represents an integer of 0 to 4. n represents an integer of 1 to 4.)

In the general formula (2), Ar has the same meaning as Ar in the general formula (1), and the preferred embodiments and the effects obtained are also the same.
In the general formula (2), R has the same meaning as R in the general formula (1), and the preferred embodiments and the effects obtained are the same.
In the general formula (2), m has the same meaning as m in the general formula (1), and the preferred embodiments and the effects obtained are also the same.
In the said General formula (2), n is synonymous with n in the said General formula (1), A preferable aspect and the effect acquired are also the same.

(Ultraviolet absorber represented by the general formula (3))
Furthermore, it is preferable that the ultraviolet absorber represented by the general formula (2) is an ultraviolet absorber represented by the following general formula (3). By adopting such a configuration, the compound represented by the general formula (2) has a further excellent bleed-out suppressing effect while maintaining the ultraviolet absorbing ability or further improving these. Can be. Further, the stability as a compound is further improved, and the ultraviolet absorbing ability can be maintained for a longer period. Furthermore, synthesis is easier, and the cost and productivity are further improved.

  It is preferable that the polyester film in this invention contains 0.1-10 mass% of above-mentioned ultraviolet absorbers on the basis of the mass of a polyester film. By setting it as this content, suitable ultraviolet absorptivity can be show | played efficiently and deterioration of the other member by ultraviolet-ray can be suppressed suitably. At the same time, bleeding out of the ultraviolet absorber can be suppressed. It also has excellent transparency. If the content is too small, the ultraviolet absorption ability tends to be low. From such a viewpoint, the content of the ultraviolet absorber is preferably 0.2% by mass or more, more preferably 0.3% by mass or more. On the other hand, if the content is too large, bleeding tends to occur and the transparency tends to be poor. From this viewpoint, the content of the ultraviolet absorber is preferably 5% by mass or less, more preferably 3% by mass or less.

(Production method of UV absorber)
The ultraviolet absorber represented by any one of the general formulas (1) to (3) can be synthesized by any method. For example, known patent documents and the like, for example, Examples and Comparative Examples of JP-A-57-209799, Examples and Comparative Examples of JP-A-7-11231, Examples and Comparative Examples of JP-A-2009-286717 It can be synthesized from any anthranilic acid and any acid chloride with reference to examples.

(Other additives)
In the polyester film of the present invention, in addition to the above ultraviolet absorber, a lubricant (wax etc.), particles (organic particles, inorganic particles, organic-inorganic composite particles, etc.), antioxidants, etc., as long as the object of the present invention is not impaired In addition, additives such as an antistatic agent, a release agent, and a fluorescent brightening agent may be contained. In addition, other ultraviolet absorbers (metallic ultraviolet absorbers, ultraviolet absorbers described in, for example, JP-A-7-11231, etc.) can be used in combination as long as the object of the present invention is not impaired.

[Production method of polyester film]
Hereinafter, an example is given and demonstrated about the manufacturing method of the polyester film in this invention.
First, a polyester composition is obtained in which a predetermined amount of an ultraviolet absorber and optionally other additives are added to the above-described polyester as necessary. For example, a master batch made of polyester and containing an ultraviolet absorber and a polyester chip for dilution may be mixed so that the content of the ultraviolet absorber in the obtained polyester film falls within a predetermined range. The obtained polyester composition is sufficiently dried using a hot air dryer or a vacuum apparatus. Then, it is put into an extruder and melted at a temperature equal to or higher than the melting point of the polyester, for example, 260 to 320 ° C., and the molten resin is filtered through a filter to remove foreign matters, and a molten sheet is removed from a die having a slit-shaped die. Extruded and cooled, for example, rapidly cooled and solidified on a casting drum of about 10 to 70 ° C. to obtain an unstretched film. The thickness of the unstretched film obtained here may be determined in consideration of the thickness of the film to be obtained and the stretch ratio.

  Next, the unstretched film is subjected to a film forming machine axial direction (hereinafter, sometimes referred to as a longitudinal direction or a longitudinal direction or MD) or a direction perpendicular to the film forming machine axial direction and the thickness direction (hereinafter referred to as a horizontal direction or a width direction). (It may be referred to as TD). Here, “stretching in the uniaxial direction” does not necessarily limit that the film is not stretched in the biaxial direction. As long as it satisfies the in-plane molecular orientation (retardation) defined by the present invention, It may be stretched in the axial direction. Such uniaxial stretching is preferably performed in the lateral uniaxial direction from the viewpoint of easy formation of an easily adhesive layer during production of the film and from the viewpoint of productivity. Hereinafter, the case of extending in the uniaxial direction in the lateral direction will be described.

In addition, it is preferable to apply | coat the coating liquid for forming the easily bonding layer mentioned later on a film surface before extending | stretching. This may dry the coating liquid, promote the reaction of the components in the coating liquid, or improve the adhesion between the easy-adhesive layer and the film, by heat in the subsequent transverse stretching process or heat setting process. it can.
And preferably, the unstretched film coated with the coating liquid is led to a stenter and is transversely, preferably at 80 to 110 ° C., preferably 2.0 to 6.0 times, more preferably 3.0 to 4 times. Stretch by 5 times to obtain a lateral uniaxially stretched film. In the present invention, a polyester film having a desired retardation can be obtained by employing such stretching conditions.

Subsequently, the uniaxially stretched film is subjected to a heat treatment (referred to as heat setting) at a temperature higher than the crystallization temperature of the polyester and lower than the melting point, preferably 150 to 240 ° C. for 1 to 60 seconds. Thereby, mechanical characteristics, heat resistance, and transparency can be further improved. In this way, a lateral uniaxially oriented film is obtained.
The laterally uniaxially oriented film is further subjected to reheat treatment while shrinking 0 to 20% in the longitudinal direction and / or the width direction at a temperature lower by 10 to 20 ° C. than the heat treatment temperature as necessary, so that the heat shrinkage rate is increased. Can be adjusted.
The uniaxial stretching in the longitudinal direction can be similarly performed with reference to the above conditions.

[Easily Adhesive Layer (PVA Easy Adhesive Layer)]
The film of the present invention contains a binder component made of a thermoplastic resin as a main component on one side of a polyester film, and has an easy adhesion layer having a surface wetting index of 60 mN / m or more (particularly different from the HC easy adhesion layer described later). In this case, the easy adhesion layer is referred to as a PVA easy adhesion layer). Such an easy-adhesion layer is excellent in adhesion to other members such as a PVA film and PVA-based water paste used for bonding with such members. That is, when pasting with a polarizer via a PVA-based water paste, as a result, the adhesiveness between the film of the present invention and the polarizer made of the PVA film is excellent. From this viewpoint, the wetting index of the surface of the PVA easy-adhesion layer is preferably 65 mN / m or more, and more preferably 70 mN / m or more. On the other hand, from the viewpoint of adhesiveness with PVA, a higher wetting index is preferable, but if it is too high, there is a possibility that the thickness of the applied water paste becomes non-uniform, so it is preferably 90 mN / m or less. More preferably, it is 80 mN / m or less, More preferably, it is 74 mN / m or less. Further, in the above, “contained as a main component” may be an aspect in which the binder component occupies the remainder other than the optional component in the PVA easy-adhesion layer described later. For example, it is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more based on the mass of the easy adhesion layer.

The binder component in the PVA easy-adhesion layer is not particularly limited as long as the above-described wetting index range is achieved, but a binder component composed of a copolymerized polyester and polyvinyl alcohol is preferable because it easily achieves the above-described wetting index range. Moreover, this is excellent in the adhesiveness of both a polyester film and PVA.
More preferably, the binder component is an embodiment comprising 40 to 90% by mass of a copolymerized polyester based on the mass of the binder component and 10 to 60% by mass of polyvinyl alcohol based on the mass of the binder component, whereby a polyester film It is further excellent in the adhesiveness of both PVA and PVA. If the content of the copolyester is too small and the content of the polyvinyl alcohol is too large, the effect of improving the adhesiveness with the polyester film tends to be low. On the other hand, the content of the copolyester is too large, and the polyvinyl alcohol When there is too little content of, there exists a tendency for the adhesive improvement effect with PVA to become low. From this viewpoint, the content of the copolyester is more preferably 50 to 80% by mass, and the content of the polyvinyl alcohol is more preferably 20 to 50% by mass.

(Copolymerized polyester)
Examples of the copolyester of the PVA easy-adhesion layer include polyesters composed of the following polybasic acid component and polyol component. The copolyester of the easy-adhesion layer in the present invention is one in which at least one of these polybasic acid component and polyol component contains two or more components.

  As polybasic acid component of copolymer polyester, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyro Examples include components derived from merit acid, dimer acid, and 5-sodium sulfoisophthalic acid. These polybasic acid components are preferably two or more types of copolyester. Such a copolyester may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid, as long as it is in a slight amount.

  As a polyol component of the copolymer polyester, ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, poly (ethylene oxide) Examples include components derived from glycol and poly (tetramethylene oxide) glycol.

  The copolyester preferably contains 1 to 16 mol% of a dicarboxylic acid component having a sulfonate group per total carboxylic acid component. Examples of the dicarboxylic acid component include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, Examples include 5-potassium sulfoterephthalic acid. The amount of the dicarboxylic acid component having such a sulfonate group is more preferably 1.5 to 14 mol%. When such a component is less than the lower limit, the hydrophilicity of the copolyester may be insufficient. On the other hand, when such a component exceeds the upper limit value, the moisture resistance of the coating layer is lowered, and for example, the function of the polarizer may be lowered.

  The copolyester of the PVA easy-adhesion layer preferably has a glass transition point (hereinafter sometimes abbreviated as Tg) of 20 to 90 ° C, more preferably 25 to 80 ° C. If the glass transition point is less than the lower limit, the films tend to block each other. On the other hand, if the glass transition point exceeds the upper limit, the effect of improving adhesiveness with PVA tends to be reduced.

  The range of the glass transition point of the copolyester can be obtained by making the copolymerization ratio of the above components moderate. Specifically, for example, with respect to the upper limit of the glass transition point, for example, the aromatic dicarboxylic acid component capable of increasing Tg such as 2,6-naphthalenedicarboxylic acid exceeds 80 mol% based on the total acid component of the copolymer polyester. By using it so that the glass transition point does not exceed the upper limit of such a range. Also, the cycloaliphatic diol and aromatic diol components capable of increasing Tg, such as 1,4-cyclohexanedimethanol and bisphenol A ethylene oxide adduct, should not exceed 60 mol% based on the total diol components of the copolymer polyester. By having it, it is possible to prevent the glass transition point from exceeding the upper limit of the range.

  On the other hand, the lower limit of the glass transition point of the copolyester can be lowered by Tg such as 1,4-butanediol, diethylene glycol, 1,6-hexanediol, poly (ethylene oxide) glycol, poly (tetramethylene oxide) glycol. By making the long-chain aliphatic diol component not exceed 60 mol% based on the total diol component of the copolyester, the glass transition point can be prevented from falling below the lower limit of the range.

  In the present invention, when forming the easy-adhesion layer on the film, it is preferable to form the coating layer composition by dissolving or dispersing the coating layer composition in water or an aqueous solution containing some organic solvent. It is preferable that the copolyester constituting is a polyester that is soluble or dispersible in water or an aqueous solution containing some organic solvent. In order to improve water dispersibility, it is preferable that a copolymer component having a functional group with a high degree of ionization such as a sulfonate and a highly hydrophilic copolymer component such as a polyalkyl ether are included.

(Polyvinyl alcohol)
As the polyvinyl alcohol of the PVA easy-adhesion layer in the present invention, it is preferable to use polyvinyl alcohol having a saponification degree of 80 to 95 mol%, more preferably 85 to 90 mol%. Examples of such polyvinyl alcohol include vinyl alcohol-vinyl acetate copolymer, vinyl alcohol-vinyl butyral copolymer, and ethylene-vinyl alcohol copolymer. Among these, vinyl alcohol-vinyl acetate copolymer, ethylene-vinyl alcohol A copolymer is preferred. Usually, the copolymerization ratio of vinyl alcohol is represented by the degree of saponification. As described above, by increasing the saponification degree of the polyvinyl alcohol of the easy-adhesion layer, it is possible to further strengthen the adhesiveness with a polarizer made of PVA-based water paste or PVA film.
If the degree of saponification is too low, the effect of improving adhesiveness tends to be reduced, while if it is too high, the moisture resistance of the easy-adhesive layer tends to be reduced.

(particle)
The PVA easy-adhesion layer preferably contains 0.1 to 5.0% by mass of particles based on the mass of the PVA easy-adhesion layer for the purpose of imparting slipperiness to the film. The content of particles is more preferably 0.2 to 3.0% by mass. If the content of the particles is less than the lower limit, the slipperiness of the film, i.e., the transportability, tends to be insufficient. On the other hand, if the content exceeds the upper limit, the haze value of the film tends to increase, making it difficult to use for display applications Tend to be.

Examples of such particles include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, antimony trioxide, Examples thereof include inorganic fine particles such as carbon black and molybdenum disulfide, and organic fine particles such as acrylic cross-linked polymers, styrene cross-linked polymers, silicone resins, fluororesins, benzoguanamine resins, phenol resins, and nylon resins. Among these, for the water-insoluble solid substance, it is preferable to select particles whose specific gravity does not exceed 3 in order to avoid sedimentation in the aqueous dispersion. Moreover, these may use 1 type and may use 2 or more types.
The average particle size of the particles in the PVA easy-adhesion layer is preferably 10 to 300 nm from the viewpoint of the balance between transparency and lubricity.

(Crosslinking agent)
It is preferable that the PVA easy-adhesion layer further contains a crosslinking agent to make the easy-adhesion layer stronger. Thereby, the improvement effect of adhesiveness becomes high. In an embodiment in which the easy-adhesion layer contains polyvinyl alcohol, such components tend to become brittle over time, so that the adhesion to the polarizer is increased by its use, but the strength of the easy-adhesion layer may decrease over time. is there. Therefore, by further containing a crosslinking agent, the crosslinking agent self-crosslinks to form a network structure, and the strength of the easy-adhesion layer can be maintained over time.

As such a cross-linking agent, epoxy-based, isocyanate-based, oxazoline-based, urethane-based, melamine-based cross-linking agents and the like can be used. Of these, oxazoline-based crosslinking agents are preferred. The oxazoline-based cross-linking agent is less likely to react with the OH group of the polyvinyl alcohol of the easy-adhesion layer than other cross-linking agents, and therefore, even if it is used, the adhesiveness is easily maintained. Two or more crosslinking agents may be used in combination.
The content of the cross-linking agent is preferably 0 to 20% by mass, more preferably 10 to 20% by mass, based on the mass of the binder component, from the viewpoint of the above effects.

(Thickness of PVA easy adhesion layer)
The thickness of the PVA easy-adhesion layer is preferably 0.01 to 1 μm. Thereby, it becomes easy to ensure wettability, and it becomes easy to achieve the said wettability. If the thickness of the easy-adhesion layer is too thin, it tends to be difficult to ensure wettability, and the effect of improving adhesiveness tends to be low. Conversely, if it is too thick, blocking occurs or the haze value increases. There is a possibility. From this viewpoint, the thickness of the easy-adhesion layer is more preferably 0.01 to 0.3 μm, further preferably 0.02 to 0.25 μm, and particularly preferably 0.02 to 0.12 μm.

[Easily adhesive layer (HC easy adhesive layer)]
When forming the hard coat layer (HC layer), the film of the present invention has the above-mentioned PVA easy-adhesion layer on one side of the polyester film, and on the other side, the surface wetting index is 40 mN / m or more, An embodiment having an easy adhesion layer of less than 60 mN / m (in particular, when distinguishing from the aforementioned PVA easy adhesion layer, this easy adhesion layer is referred to as an HC easy adhesion layer) can be exemplified as a preferred embodiment. Such an HC easy-adhesion layer is excellent in adhesion to the hard coat layer. If the wetting index is too high, the agent for forming the hard coat layer is difficult to spread and, as a result, tends to be inferior in adhesion, and if it is too low, the surface tends to be too inert to reduce the adhesion. is there. From this point of view, the wetting index of the surface of the HC easy-adhesion layer is preferably 40 mN / m or more, more preferably 45 mN / m or more, preferably 60 mN / m or less, and more preferably 55 mN / m or less.

  The HC easy-adhesion layer is not particularly limited as long as it is in the above wetting index range, but an embodiment containing a binder component made of an acrylic resin as a main component is preferable. Thereby, it is excellent by the adhesiveness of both a polyester film and HC layer. Here, the “main component” may be an aspect in which the binder component occupies the remainder other than the optional component in the HC easy-adhesion layer described later. For example, it indicates that it is 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more with respect to the mass of the HC easy-adhesion layer.

(acrylic resin)
The acrylic resin of the HC easy-adhesion layer has a glass transition point (Tg) of preferably 20 to 80 ° C, more preferably 25 to 70 ° C. Thereby, it is more excellent in HC easy adhesion. Moreover, it is excellent in blocking resistance. When the glass transition point is less than 20 ° C., the film blocking property is deteriorated. When the glass transition point is higher than 80 ° C., the film forming property is lowered, and the effect of improving the HC easy adhesion property tends to be lowered. The acrylic resin is particularly preferably an acrylic resin that is soluble or dispersible in water, but may be soluble or dispersible in water containing some organic solvent.

  Such an acrylic resin can be produced by polymerizing the following acrylic monomers. As the acrylic monomer, alkyl (meth) acrylate ((meth) acrylate may be described by combining acrylate and methacrylate. In addition, as the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl may be used. Hydroxy group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, etc.), n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc. Epoxy group-containing monomers such as glycidyl (meth) acrylate and allyl glycidyl ether; (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt) Tertiary amine salt ) Or a carboxy group or a salt thereof; (meth) acrylamide (may be described as (meth) acrylamide together with acrylamide and methacrylamide), N-alkyl (meth) acrylamide, N, N -Dialkyl (meth) acrylamide (wherein alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.) , N-alkoxy (meth) acrylamide, N, N-dialkoxy (meth) acrylamide (wherein alkoxy groups include methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), acryloylmorpholine, N-methylol (meth) Acrylamide, N-phenyl (meth) acryl Monomers containing an amide group such as amide; monomers of acid anhydrides such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, styrene (but as a copolymerization component), α-methylstyrene (but as a copolymerization component) ), Vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxy silane, alkyl maleic acid monoester, alkyl fumaric acid mono ester, alkyl itaconic acid mono ester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, acetic acid Examples thereof include monomers such as vinyl and butadiene.

  The acrylic resin can be produced according to the method described in Production Examples 1 to 3 of JP-A-63-37167. That is, a predetermined amount of sodium lauryl sulfonate as a surfactant and a predetermined amount of ion-exchanged water were charged into a four-necked flask and heated to 60 ° C. in a nitrogen stream, and then 0.5 parts of ammonium persulfate as a polymerization initiator Then, 0.2 part of sodium hydrogen nitrite is added, and a mixture of monomers capable of expressing a desired function is added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. In addition, an aqueous dispersion of an acrylic resin can be obtained by maintaining the reaction in the same temperature range for 2 hours while continuing the reaction with stirring and then cooling.

(particle)
The HC easy-adhesion layer preferably contains 0.1 to 10% by mass of particles based on the mass of the HC easy-adhesion layer for the purpose of imparting slipperiness to the film or imparting scratch resistance. . The content of particles is more preferably 0.2 to 3.0% by mass. If the content of the particles is less than the lower limit value, the slipperiness of the film, that is, the transportability tends to be insufficient, and the effect of improving the scratch resistance tends to be low. On the other hand, if the content exceeds the upper limit, the haze value of the film Tends to be high, and the cohesive force of the easy-adhesion layer tends to be low, and the adhesiveness tends to be low.

  Examples of such particles include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, antimony trioxide, Examples thereof include inorganic fine particles such as carbon black and molybdenum disulfide, and organic fine particles such as acrylic cross-linked polymers, styrene cross-linked polymers, silicone resins, fluororesins, benzoguanamine resins, phenol resins, and nylon resins. Among these, for the water-insoluble solid substance, it is preferable to select particles whose specific gravity does not exceed 3 in order to avoid sedimentation in the aqueous dispersion. Moreover, these may use 1 type and may use 2 or more types.

  The average particle diameter of the particles in the HC easy-adhesion layer is, for example, 20 to 300 nm, preferably 60 to 300 nm, and more preferably 80 to 250 nm, and has a good balance of the effect of slipperiness, scratch resistance, and particle dropout suppression. If the average particle size is too large, the particles are liable to fall off, and if it is too small, the lubricity and scratch resistance tend to be lowered.

(Crosslinking agent)
It is preferable that the HC easy-adhesion layer further contains a crosslinking agent to make the easy-adhesion layer stronger. Thereby, the improvement effect of adhesiveness becomes high.
As such a cross-linking agent, epoxy-based, isocyanate-based, oxazoline-based, urethane-based, melamine-based cross-linking agents and the like can be used. Of these, an oxazoline-based crosslinking agent is preferred from the viewpoint of superior adhesiveness. Moreover, the oxazoline crosslinking agent is easy to handle and the pot life of the coating solution is relatively long. Two or more crosslinking agents may be used in combination.

  As the oxazoline-based crosslinking agent, a polymer containing an oxazoline group is preferable. It can be prepared by polymerization with addition polymerizable oxazoline group-containing monomers alone or with other monomers. As addition-polymerizable oxazoline group-containing monomers, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not particularly limited as long as it is a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (wherein the alkyl group includes a methyl group, an ethyl group, and an n-propyl group). Group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group) and the like (meth) acrylic acid esters; (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid , Unsaturated carboxylic acids such as crotonic acid, styrene sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide N-alkyl (meth) acrylamide N, N-dialkyl (meth) acrylic (Wherein the alkyl group is a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.) Vinyl esters such as vinyl acetate, vinyl propionate, and (meth) acrylic acid ester units added with polyalkylene oxide; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene And halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like.

  The content of the crosslinking agent is preferably from 0.1 to 30% by mass, more preferably from 10 to 25% by mass, based on the mass of the binder component, from the viewpoint of the above effects. If the amount is too small, the cohesive force of the easy-adhesion layer tends to be difficult to increase, and the effect of improving adhesiveness tends to be low. On the other hand, if the amount is too large, the easy-adhesion layer becomes very hard, stress relaxation tends to decrease, and the effect of improving adhesiveness tends to decrease.

(HC adhesive layer thickness, refractive index)
The thickness of the HC easy-adhesion layer is preferably 40 to 100 nm. This makes it easy to achieve the wettability. If the thickness of the easy-adhesion layer is too thin, the wettability tends to be low, and the effect of improving adhesiveness tends to be low. On the other hand, if it is too thick, blocking may occur or the haze value may increase. From this viewpoint, the thickness of the easy-adhesion layer is more preferably 50 to 90 nm.
The refractive index of the HC easy-adhesion layer is preferably 1.58 to 1.65. By satisfying the thickness and the refractive index at the same time, an effect of reducing rainbow spots due to interference with the hard coat layer when the hard coat layer is formed can be obtained.

[Method of forming easy-adhesion layer]
The easy-adhesion layer is used in the form of an aqueous coating liquid such as an aqueous solution, aqueous dispersion or emulsion containing the components constituting the easy-adhesion layer (hereinafter sometimes simply referred to as a coating liquid). It is preferable to form a coating film by coating, drying the coating film, and effecting as necessary. In order to form a coating film, other components other than the above components, for example, an antistatic agent, a colorant, a surfactant, an ultraviolet absorber, and the like can be added to the coating liquid as necessary.
The solid content concentration of the coating liquid is usually 20% by mass or less, and preferably 1 to 10% by mass. If this ratio is less than the lower limit, the applicability to the polyester film may be insufficient. On the other hand, if the ratio exceeds the upper limit, the stability of the coating liquid and the appearance of the easy-adhesion layer may be deteriorated.

  Application of the coating liquid to the polyester film can be carried out at any stage, but it is preferably carried out during the production process of the polyester film, and more preferably applied to the polyester film before the orientation crystallization is completed. . Here, the polyester film before completion of crystal orientation includes an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and the like. Especially, in this invention, it is preferable to apply | coat the aqueous coating liquid of the said composition to an unstretched film, and to perform longitudinal stretching or horizontal stretching and heat setting as it is.

When applying the coating solution to the film, as a pretreatment for improving the coating property, the film surface is subjected to physical treatment such as corona surface treatment, flame treatment, plasma treatment, or chemically with the composition. It is preferable to use an inert surfactant in combination.
Such a surfactant promotes the wetting of the coating liquid on the polyester film. For example, polyoxyethylene alkylphenyl ether, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl Anionic and nonionic surfactants such as sulfates, alkyl sulfonates and alkyl sulfosuccinates can be mentioned. It is preferable that 1-10 mass% of surfactant is contained in the composition which forms a coating film.

  As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination. In addition, an easily bonding layer may be formed only in the single side | surface of a film as needed, and may be formed in both surfaces.

[Characteristics of film]
(UV absorption capacity (spectral transmittance))
The film of the present invention preferably has the above-mentioned ultraviolet absorber having a specific structure, so that it has excellent ultraviolet absorbing ability, and at the same time, there is little bleeding out of the ultraviolet absorber, thereby reducing sublimates upon heating, An ultraviolet-absorbing film having excellent appearance and few defects can be obtained.

  The film of the present invention preferably has a light transmittance of 10% or less at a wavelength of 360 nm. Within such a range, the film has excellent ultraviolet absorbing ability, and when used outdoors such as by adopting the film of the present invention for a mobile device, the film and various kinds of films located inside the film from ultraviolet rays in sunlight. A member can be protected and these deteriorations can be suppressed. Further, various members can be protected from ultraviolet rays emitted from the light source of the liquid crystal display device, and deterioration can be suppressed. The light transmittance at a wavelength of 360 nm is more preferably 5.0% or less, and particularly preferably 1.0% or less. At the same time, the light transmittance at a wavelength of 390 nm is preferably 80% or more. As described above, when the light transmittance is abruptly changed from the ultraviolet region to the visible light region, excessive absorption in the visible light region due to the absorption of ultraviolet rays is suppressed, thereby causing discoloration of the film. Suppressed and excellent in colorlessness. In addition, a light transmittance in the visible light region is improved, and a liquid crystal display device with high luminance can be obtained. From this, the light transmittance at a wavelength of 390 nm is more preferably 81% or more, and particularly preferably 82% or more. In order to achieve such an embodiment, an ultraviolet absorber preferably defined by the present invention may be used. Moreover, what is necessary is just to make the addition amount into the range which this invention defines preferably.

[Hard coat layer]
The film of the present invention can have a hard coat layer on the HC easy-adhesion layer. And by forming an electrode on this, the electrode defect by the protrusion of a polyester film or an easily bonding layer, and a foreign material can be suppressed, maintaining a softness | flexibility.
The thickness of the hard coat layer is preferably 1.0 to 6.0 μm from the viewpoint of imparting sufficient smoothness and scratch resistance.

(Curable resin)
Such a hard coat layer is formed of a curable resin such as a thermosetting resin or a radiation curable resin as a main component. In the present invention, a radiation curable resin is preferable, and an ultraviolet curable resin is particularly preferable from the viewpoint that excellent hardness is obtained and excellent smoothness and scratch resistance can be imparted for a transparent electrode. The hard coat layer in the present invention is preferably made of the following radiation curable resin as a main component. Here, “as the main component” means 50% by mass or more, preferably 80% by mass or more based on the mass of the hard coat layer.

  A radiation curable resin is a monomer, oligomer, or polymer that can be crosslinked and cured by radiation. As the radiation curable resin in the present invention, it is possible to increase the crosslink density after curing, from the viewpoint that the effect of improving the surface hardness can be increased, and the effect of improving the transparency can be increased. A polyfunctional (meth) acrylate compound such as a polyfunctional (meth) acrylate monomer, a polyfunctional (meth) acrylate oligomer, or a polyfunctional (meth) acrylate polymer is preferable. Here, “(meth) acrylate” represents acrylate and / or methacrylate.

  Such a polyfunctional (meth) acrylate compound is a compound containing a (meth) acryloyl group in the molecule, and preferably contains at least two (meth) acryloyl groups in the molecule. As a result, the crosslinking reaction of the radiation curable resin easily proceeds, and the effect of improving the surface hardness can be enhanced. In addition, the polyfunctional (meth) acrylate compound in this invention may contain other polymerizable functional groups other than a (meth) acryloyl group in a molecule | numerator. Here, the “(meth) acryloyl group” represents an acryloyl group and / or a methacryloyl group.

  Specific examples of the polyfunctional (meth) acrylate compound containing at least two (meth) acryloyl groups in the molecule include, for example, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri ( (Meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Alkyl modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa Monomers such as (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate), melamine (meth) acrylate, and oligomers of about 2 to 20 mer composed of at least one of these, and polymer composed of at least one of these Can be mentioned. Such polyfunctional (meth) acrylate compounds may be used alone or in combination of two or more.

  The number of repeating units of the polyfunctional (meth) acryl oligomer / polymer is not particularly limited. For example, the number average molecular weight is preferably 150 to 1,000,000, preferably 1,000 to 500,000, and the effect of improving the coating appearance is enhanced. Can do. When the number average molecular weight is less than 150 or exceeds 1,000,000, the viscosity tends to be too low or too high, and the effect of improving the coating appearance tends to be low.

  Polyfunctional (meth) acrylate compounds containing at least two (meth) acryloyl groups in the molecule as described above are, for example, Aronics M-400, M-450, M-305, M-309, M-310, M-315, M-320, TO-1200, TO-1231, TO-595, TO-756 (above, manufactured by Toagosei), KAYARD D-310, D-330, DPHA, DPHA-2C (above, Nipponization) Such as Nikarac MX-302 (manufactured by Sanwa Chemical Co., Ltd.).

(Method for forming hard coat layer)
The hard coat layer can be obtained by applying a coating liquid (HC agent) for forming the hard coat layer to the surface on which the hard coat layer is to be formed, drying by heating, and curing.
The HC agent in the present invention is a solution in which the above-described curable resin and optional components are added to a solvent and mixed. When adding each component, it may be added as a solid such as a powder, or a solid in a form of a solution or a dispersion using an appropriate solvent may be added. The solvent used for the HC agent is not particularly limited. For example, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohols such as methanol, ethanol, propanol, n-butanol, secondary butanol and isopropyl alcohol, butyl acetate, Esters such as ethyl acetate, aromatic hydrocarbons such as toluene and xylene, glycol ethers such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate can be used, and the dispersibility of the HC agent is improved. The appearance of the coat layer is improved. Of these, ketones are preferable from the viewpoint of good solubility, and methyl ethyl ketone and methyl isobutyl ketone are particularly preferable. As solid content concentration of HC agent, 1-70 mass% is preferable, and 10-60 mass% is more preferable, By setting it as such an aspect, defects, such as a smear, can be reduced.

As a method for applying the HC agent, a method known per se can be adopted. For example, the lip direct method, comma coater method, slit reverse method, die coater method, gravure roll coater method, blade coater method, spray coater method, air knife coat method, dip coat method, bar coater method and the like can be preferably mentioned. By these application methods, the HC agent is applied on the transparent substrate to form a coating film, and the obtained coating film is heated and dried. As conditions for heat drying, it is preferable to heat at 50 to 150 ° C. for 10 to 180 seconds, more preferably to heat at 50 to 120 ° C. for 20 to 150 seconds, and to heat at 50 to 80 ° C. for 30 to 120 seconds. Is particularly preferred. After heat drying, the HC coating is cured by ultraviolet irradiation or electron beam irradiation. For UV irradiation, the irradiation amount is preferably 10 to 2,000 mJ / cm ^2, more preferably 50~1,500mJ / cm ^2, particularly preferably a 100~1,000mJ / cm ^2. Thus, a hard coat layer can be formed.

[Transparent conductive layer]
In the present invention, an HC easy-adhesion layer and a hard coat layer are preferably formed on the surface opposite to the PVA easy-adhesion layer, or the surface opposite to the PVA easy-adhesion layer, and a transparent An electrode layer can be formed to make a transparent electrode.

  In the present invention, examples of the transparent conductive layer include a layer made of a crystalline metal or a crystalline metal compound. Examples of the component constituting the transparent conductive layer include metal oxides such as silicon oxide, aluminum oxide, titanium oxide, magnesium oxide, zinc oxide, indium oxide, and tin oxide. Of these, a crystalline layer mainly composed of indium oxide is preferable, and a layer made of crystalline ITO (Indium Tin Oxide) is particularly preferably used. When the transparent conductive layer is a crystalline film, for example, the environmental reliability required for a touch panel tends to be improved. The method of crystallization is not particularly limited, and for example, the crystallization can be performed by heat treatment at 120 to 160 ° C. for about 60 to 90 minutes.

A layer made of a conductive polymer such as polyacetylene, polyparaphenylene, polythiophene, polyethylenedioxythiophene, polypyrrole, polyaniline, polyacene, or polyphenylene vinylene can also be employed.
The film thickness of the transparent conductive layer is preferably 5 to 50 nm from the viewpoints of transparency and conductivity. More preferably, it is 5-30 nm. When the film thickness of the transparent conductive layer is less than 5 nm, the resistance value tends to be inferior in stability with time, and when it exceeds 50 nm, the transparency tends to decrease. Further, the color tone of the film becomes strong, and when forming a pattern, the pattern tends to be emphasized.

  When the transparent electrode of the present invention is used for a touch panel, the transparent conductive layer has a surface resistance value of 100 to 1000 Ω / □, more preferably 100 to 10 nm at a thickness of 10 to 30 nm due to reduction of power consumption of the touch panel and necessity for circuit processing. It is preferable to use a transparent conductive layer exhibiting a range of 600Ω / □.

(Method for forming transparent conductive layer)
The transparent conductive layer can be formed by a known method. For example, a physical formation method (such as a DC magnetron sputtering method, an RF magnetron sputtering method, an ion plating method, a vacuum deposition method, a pulse laser deposition method) (Physical Vapor Deposition (PVD)) or the like can be used, but DC magnetron sputtering is desirable from the viewpoint of industrial productivity of forming a metal compound layer having a uniform film thickness over a large area. In addition to the physical formation method (PVD), a chemical formation method such as chemical vapor deposition (CVD) or a sol-gel method can be used. A sputtering method is preferred.

  In addition, the transparent conductive layer in this invention may be formed in the whole surface of the film, and may be formed in a part. Moreover, when using as a transparent electrode of a capacitive touch panel, the transparent conductive layer may be patterned. Here, patterning refers to an aspect in which a portion where the transparent conductive layer exists in a prescribed shape and a portion where the transparent conductive layer does not exist are formed. That is, the transparent conductive layer is formed on part of the film. The specified shape may be a known shape that can be used as an electrode of a capacitive touch panel. For example, there are fine line and diamond patterns. The patterning method is not particularly limited, and a conventionally known etching method can be used.

[Polarizer]
The transparent electrode film of the present invention has a PVA easy-adhesion layer on one side of a polyester film, and preferably has an HC easy-adhesion layer and a hard coat layer on the opposite side of the PVA easy-adhesion layer. As a transparent electrode provided with a transparent electrode layer, a polarizer made of polyvinyl alcohol can be provided on the PVA easy-adhesion layer. By adopting such a configuration, a polarizing plate and a transparent electrode are conventionally laminated as a laminated structure of polarizer / polarizer protective film / electrode base film / transparent electrode layer. As the laminated structure of the polarizer protective film / electrode base film / transparent electrode layer, the film can be omitted to improve transparency, reduce weight, reduce costs, and the like.
Moreover, by using the film having the preferred embodiment of the present invention as the support substrate for the polarizer as described above, iodine can be protected while enhancing the durability of the polarizer, and the hue reproducibility is excellent.

The method of compounding with the polarizer is not particularly limited, and examples thereof include bonding with a film-like polarizer in which dichroic molecules are uniaxially oriented in a matrix. As the dichroic molecule, polyiodine ion is used. In many cases, a polyvinyl alcohol (PVA) film is used as the film-like polarizer material.
About the method of compounding with a polarizer, you may use the apply | coating method other than the method of laminating | stacking with a polarizer film. Examples of the coating type include a method in which liquid crystal molecules are aligned by coating shear force, and the applied reactive liquid crystal molecules are aligned and solidified by irradiation with polarized light.

More specifically, the polarizing plate is such that the polarizer and the film of the present invention are parallel to the transmission axis direction of the polarizer and the direction of the maximum refractive index in the plane of the film of the present invention. It can be obtained by combining, and by doing so, it becomes possible to reduce the influence on the linearly polarized light by the film of the present invention, that is, the change in the polarization state.
In addition, the obtained polarizing plate can ensure the stability of the optical axis that can prevent color shift and color spot of the liquid crystal display, and there is little variation in the screen of the display image quality when incorporated in the display. Higher performance display image quality is manifested.

  In the bonding with the polarizer, the film of the present invention may be used for only one of the supporting substrates to be bonded to both sides of the polarizer, or may be used for both. In addition, when the polarizer and the film of the present invention are combined, it is preferable to directly laminate the polarizer and the film of the present invention via an easy-adhesion layer. However, the polarizer and the adhesive layer (for example, PVA water glue) And the adhesive layer and the easy-adhesion layer of the present invention may be bonded together. At that time, care must be taken so that the adhesive layer does not impair the optical function of the polarizing plate.

  Hereinafter, the present invention will be described in detail with reference to examples. The physical properties were measured and evaluated by the following methods. “PET” represents polyethylene terephthalate.

(1) Film thickness A film sample is sandwiched between spindle detectors (K107C manufactured by Anritsu Electric Co., Ltd.), and 10 thicknesses are measured at different positions using a digital differential electronic micrometer (K351 manufactured by Anritsu Electric Co., Ltd.). Then, the average value was obtained and defined as the film thickness.

(2) Refractive index and retardation of film Measured with an Abbe refractometer (light source: sodium D line 589 nm, mounting solution: methylene iodide) according to JIS-K7105. In the measurement, the lateral direction of the film was set to 0 °, the refractive index was measured every 5 °, and the maximum refractive index nTD and the refractive index nMD in the direction orthogonal to the maximum refractive index were obtained.
Next, nTD and nMD obtained above were applied to the following formula, and the calculated value was defined as retardation (Re, unit: nm).
Re (nm) = | nTD-nMD | × film thickness (nm)
In addition, the film thickness uses the value which measured the thickness of the place which measured the refractive index according to the method of said (1).

(3) Spectral transmittance (UV absorption ability)
Using a spectrophotometer (Shimadzu UV-3101PC), the light transmittance at wavelengths of 360 nm and 390 nm was measured in the wavelength range of 300 to 800 under the conditions of a scanning speed of 200 nm, a slit width of 20 nm, and a sampling pitch of 1.0 nm. The evaluation was based on the following criteria.
360 nm: ◎: 1% or less, ◯: over 1%, 5% or less, △: over 5%, 10% or less, x: over 390 nm, ◎: 82% or more, ◯: 81% Or more, less than 82%, Δ: 80% or more and less than 81%, ×: 70% or more and less than 80%, XX: less than 70%

(4) Wetting index According to JIS-C2151, it measured in the room | chamber interior adjusted to temperature 23 +/- 2 degreeC and humidity 50 +/- 5%. As the wetting index solution, a product manufactured by Wako Pure Chemical Industries, Ltd., in which formamide and ethylene glycol monoethyl ether were mixed at a predetermined ratio and a very small amount of dye having a high degree of coloring was added, was used. A cotton swab was soaked in enough that the wetting index solution was not applied, and was applied horizontally to the sample and moved in one direction to apply the wetting index solution. Application was completed in 0.5 seconds. If this liquid film does not break and remains in the state of being applied for 2 seconds or more, the process proceeds to a liquid mixture with the next highest surface tension. Conversely, in less than 2 seconds, the liquid film is formed. If it breaks or shrinks as a whole, it proceeds to the next liquid with a low surface tension. This operation is repeated and continued until the wetting index liquid closest to wetting the surface for exactly 2 seconds can be selected. The numerical value (unit: mN / m) of the surface tension of the selected wetting index liquid was taken as the wetting index at that location. The measurement was performed 5 times at different locations, and the average value was taken as the result.

(5) PVA easy adhesion (cross cut test)
Using the film having a polarizer obtained in Examples, the PVA adhesiveness was evaluated based on a cross-cut tape test in JIS K5400 (1990).
First, 25 squares of 2 mm × 2 mm square cuts were made using a cutter knife and a cutter guide on the test surface (polarizer surface). The cellophane tape is strongly pressure-bonded to the grid area, the end of the tape is peeled off at an angle of 45 °, and the state of the polarizer peeling (number of grids peeled off) at the grid is observed. Judged.
(PVA easy adhesion criteria)
: 0
○: 1 to 5
Δ: 6-9
X: 10 or more In addition, the square which peeled 1/4 or more by area was counted as 1 square, and it was determined that the thing peeled less than 1/4 was not peeled.

(6) HC easy adhesion (cross cut test)
Using the film having the hard coat layer obtained in the examples, HC adhesion was evaluated in accordance with a cross-cut tape test in JIS K5400 (1990).
First, 25 squares of 2 mm × 2 mm square cuts were made on the test surface (hard coat surface) using a cutter knife and a cutter guide in the hard coat layer. The cellophane tape is strongly pressure-bonded to the grid area, the end of the tape is peeled off at an angle of 45 °, and the state of the hard coat layer peeling (number of grids peeled off) at the grid is observed, and the following evaluation criteria Judged by.
(HC criteria for easy adhesion)
: 0
○: 1 to 5
Δ: 6-9
X: 10 or more In addition, the square which peeled 1/4 or more by area was counted as 1 square, and it was determined that the thing peeled less than 1/4 was not peeled.

(7) Haze and total light transmittance The haze and total light transmittance were measured using a haze meter (NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS-K7136. It was set as the average of arbitrary 5 places. The total light transmittance was evaluated according to the following criteria.
(Total light transmittance criteria)
○: 88% or more Δ: 85% or more and less than 88% ×: less than 85%

(8) Bleed-out property (Δhaze)
About the film obtained in the Example, it heated at 150 degreeC * 60 minute (s) in oven, and calculated | required the amount of haze changes (haze difference, (DELTA) haze 1) before and behind that.
Next, for each film sample, a basic film was prepared in the same manner except that it did not contain an ultraviolet absorber, heated in an oven at 150 ° C. for 60 minutes, and the amount of haze change before and after that (haze difference, Δhaze) 0) was obtained.
The value of Δhaze 1 is subtracted from the value of the haze change amount (Δhaze 0) not caused by the bleed-out of the ultraviolet absorber to obtain the haze change amount (Δhaze) caused by the bleed-out of the ultraviolet absorber. The bleed-out property of the ultraviolet absorber was evaluated according to the following criteria. The haze measurement method was as described in (7) above.
(Bleedout criteria)
◎: Δ haze is 1.5% or less ○: Δ haze exceeds 1.5% to 3% or less Δ: Δ haze exceeds 3% to 5% or less ×: Δ haze exceeds 5% to 8% or less XX : Δhaze exceeds 8%

[Example 1]
5 parts by mass of an ultraviolet absorber represented by the following general formula (3) and 95 parts by mass of polyethylene terephthalate (PET, intrinsic viscosity 0.65 (o-chlorophenol, 25 ° C.)) are prepared, and these are used in an extruder. Then, a UV absorber was kneaded into PET to prepare a master batch (inherent viscosity 0.60 (o-chlorophenol, 25 ° C.)) containing 5% by weight of the UV absorber.

Using the above polyethylene terephthalate (PET) for dilution, mixing with the masterbatch containing the ultraviolet absorber obtained above, blended so that the content of the ultraviolet absorber is 1% by mass in the obtained film And it extruded from the extruder and created the unstretched film.
Next, an aqueous coating liquid 1 having the following composition was applied to one side of the unstretched film, and an aqueous coating liquid 2 was applied to the opposite side so that the easy-adhesion layer thickness after drying was 80 nm and 60 nm, respectively.

(Water-based coating solution 1)
Copolyester: 59 mol% terephthalic acid component, 35 mol% isophthalic acid component, 6 mol% 5-sodium sulfoisophthalic acid component, 59 mol% ethylene glycol component, 38 mol% diethylene glycol component, 5 mol% triethylene glycol component An aqueous dispersion of a copolymerized polyester having a glass transition point Tg of 40 ° C. was used.
Polyvinyl alcohol: Polyvinyl alcohol having a saponification degree of 85 mol% was used by adding ion exchange water to prepare a polyvinyl alcohol aqueous solution having a concentration of 5% by mass.
Subsequently, the aqueous dispersion of the above-mentioned copolymerized polyester and the aqueous polyvinyl alcohol solution are mixed so that the solid content mass ratio of the copolymerized polyester and polyvinyl alcohol is 60:40, and the solid content concentration is 3.0% by mass. The aqueous coating liquid 1 was prepared by diluting with ion exchange water.

(Water-based coating liquid 2)
Acrylic resin: An aqueous dispersion of acrylic resin (Tg 25 ° C.) consisting of 65 mol% methyl methacrylate, 28 mol% ethyl acrylate, 2 mol% 2-hydroxyethyl methacrylate and 5 mol% N-methylol acrylamide was used.
Cross-linking agent: An aqueous dispersion of an oxazoline-based cross-linking agent that is 15 mol% methacrylic acid, 33 mol% methyl methacrylate, 6 mol% polyethylene glycol (n = 10) methacrylate, 46 mol% 2-isopropenyl-2-oxazoline is used. It was.
Surfactants: The composition was used _{C 18 H 35 O- (C 2} H 4 O) surfactants polyoxyethylene oleyl ether is 12 -H.

Next, the aqueous dispersion of the acrylic resin, the aqueous dispersion of the oxazoline-based crosslinking agent, and the surfactant are mixed so that the solid content mass ratio is 80: 15: 5, and the solid content concentration is 4. The aqueous coating liquid 2 was obtained by diluting with ion-exchanged water so as to be 0% by mass.
Next, the unstretched film coated with the aqueous coating liquid was guided to a stenter, preheated at 100 ° C., and stretched 3.8 times (lateral stretching ratio) in the transverse direction at a stretching temperature of 110 ° C. Then, it heat-processed for 10 second at 235 degreeC in the crystallization zone, and obtained the laminated film. In the heat treatment, relaxation was adjusted to 1.5% in the vertical direction and 2.0% in the horizontal direction to adjust the heat shrinkage rate. The evaluation results of the obtained film are shown in Table 1.

[Examples 2 and 3, Comparative Example 1]
A film was obtained in the same manner as in Example 1 except that the transverse draw ratio was as shown in Table 1. The evaluation results of the obtained film are shown in Table 1.

[Example 4]
A film was obtained in the same manner as in Example 2 except that the thickness of the film was changed to 80 μm. The evaluation results of the obtained film are shown in Table 1.

[Example 5]
A film was obtained in the same manner as in Example 2 except that the aqueous coating liquid 2 was not applied and the HC easy-adhesion layer was not formed. The evaluation results of the obtained film are shown in Table 1. The film obtained in Example 5 was insufficient in adhesion with the HC layer. The wetting index on the HC easy-adhesion layer side was evaluated on the surface of the polyester film.

[Examples 6 and 7]
A film was obtained in the same manner as in Example 2 except that the following aqueous coating solution 3 (Example 6) or aqueous coating solution 4 (Example 7) was used instead of the aqueous coating solution 1. The evaluation results of the obtained film are shown in Table 1.

(Water-based coating solution 3)
In the aqueous coating solution 1, an aqueous dispersion of copolymerized polyester and an aqueous polyvinyl alcohol solution are mixed so that the solid content mass ratio is 70:30, and ion exchange is performed so that the solid content concentration is 3.0 mass%. Diluted with water to obtain aqueous coating solution 3.

(Water-based coating solution 4)
The aqueous dispersion of the copolyester used in the aqueous coating solution 1 and the aqueous polyvinyl alcohol solution are mixed so that the solid content mass ratio is 40:60, so that the solid content concentration is 3.0% by mass. The aqueous coating liquid 4 was obtained by diluting with ion-exchanged water.

[Examples 8 and 9]
A film was obtained in the same manner as in Example 2 except that the coating amount was adjusted and the thickness of the PVA easy-adhesion layer after drying was as shown in Table 1. The evaluation results of the obtained film are shown in Table 1.

[Examples 10 and 11]
A film was obtained in the same manner as in Example 2 except that the coating amount was adjusted and the thickness of the HC easy-adhesion layer after drying was as shown in Table 1. The evaluation results of the obtained film are shown in Table 1.

[Example 12]
A film was obtained in the same manner as in Example 2 except that the ultraviolet absorber was replaced with the ultraviolet absorber represented by the following general formula (4). The evaluation results of the obtained film are shown in Table 1.

[Comparative Example 2]
A film was obtained in the same manner as in Example 2 except that the aqueous coating liquid 1 was not applied and a PVA easy-adhesion layer was not formed. The evaluation results of the obtained film are shown in Table 1. The film obtained in Comparative Example 2 was not suitable for adhesion with the polarizer. The wetting index on the PVA easy-adhesion layer side was evaluated on the surface of the polyester film.

[Production Example 1] Formation of hard coat layer One side of the film obtained above (if it has a PVA easy-adhesion layer, the opposite side of the PVA easy-adhesion layer, and if it has an HC easy-adhesion layer, A hard coat layer was formed on the surface of the HC easy-adhesion layer by the following method.
A mixture of ditrimethylolpropane tetraacrylate (structural formula (5)) and a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (structural formula (6)) is blended so that the mass ratio upon drying is 50:50. To do. It was diluted with an organic solvent in which methyl ethyl ketone and butyl acetate were blended so as to have a mass ratio of 50:50 to a concentration of 20 to 30% by mass to prepare a coating solution for forming a hard coat layer. This coating solution was applied to the film using a Mayer bar # 6 so that the thickness when dried was 3 μm.

After application, the film was dried in an oven at 70 ° C. for 1 minute, and then irradiated with ultraviolet rays having an intensity of 300 mJ / cm ² to be sufficiently cured to form a hard coat layer.

[Production Example 2] Production of transparent electrode On the hard coat layer of the film having the hard coat layer obtained above, indium oxide and tin oxide are in a composition having a weight ratio of 95: 5 and a packing density of 98%. Using a tin oxide target, an ITO layer (refractive index of 2.1) as a transparent conductive layer was formed by a sputtering method to obtain a transparent electrode. The film thickness of the formed ITO layer was 40 nm.

[Production Example 3] Preparation of polarizing plate A polarizing plate was prepared by the following method using the transparent electrode obtained above.
1. Production of polyvinyl alcohol (PVA) film (1) 10 g of PVA having a polymerization degree of 1800 or more is put into 100 ml of water, and stirred while heating to dissolve PVA to obtain an aqueous PVA solution.
(2) PVA obtained by preparing one glass plate (about 40 cm × 40 cm), two plastic plates cut into a 1 mm thick strip (1 cm × 40 cm) and one glass rod (50 cm). The solution is dropped on a glass plate, and a plastic strip is used as a spacer, and it is uniformly spread with a glass rod.
(3) After extending PVA, a glass plate is left still on a horizontal stand, a water | moisture content is evaporated, and a PVA film is created.

2. Iodine dyeing and stretching (1) Add 0.2 g of iodine and 0.5 g of potassium iodide to a small amount of water to dissolve iodine. This solution is added to 500 ml of 4% boric acid solution to form a dyeing solution.
(2) The PVA film cut to an appropriate size is immersed in the staining solution for about 15 seconds.
(3) The film is pulled up from the dyeing solution and spread on the filter paper to absorb water droplets.
(4) Prepare two stretchers, wrap the end of the film around a strip-shaped plate, 3 to 3.5
Double-stretch and leave to stretch for about 30 minutes to dry. A polarizer is thus obtained.

3. Bonding The polarizer obtained in the above steps 1 and 2 is arranged into a shape that can be easily bonded to the transparent electrode. Next, an aqueous solution prepared so that PVA has a concentration of 5% by mass as water paste is uniformly applied at 10 g / m ² on the surface of the transparent electrode obtained in Production Example 2 on the PVA easy-adhesion layer side, A polarizer was attached to the resultant and dried at 80 ° C. for 10 minutes. At this time, the alignment direction of the polarizer and the alignment direction of the transparent electrode were made parallel to each other. Those bonded to one side are used for the easy adhesion test. On the opposite surface of the polarizer, a film having no hard coat layer of the used transparent electrode and no transparent conductive layer was bonded in the same manner to prepare a polarizing plate.

[Evaluation of interference spots]
In a commercially available liquid crystal display (20 inches), the polarizing plate having the transparent conductive layer obtained above is disposed in place of the viewing-side polarizing plate originally incorporated so that the transparent conductive layer is on the viewing side. I assembled the display again. At this time, the alignment direction of the polarizing plate having the transparent conductive layer was the same as the alignment direction of the polarizing plate on the viewing side that was originally incorporated. The display was laid horizontally with the screen facing upward, and a fluorescent lamp (three-wave tube) was installed 30 cm above the screen. White was displayed on the screen, the screen was illuminated with a fluorescent lamp installed above, and interference spots were visually observed with polarized sunglasses. At that time, the viewing direction was changed to search for a particularly easily visible position of the interference spots, and evaluation was performed using the following indices.
(Interference spot criteria)
A: No interference spots are visible.
○: Interference spots are hardly visible.
Δ: Some interference spots are visible.
X: Interference spots look strong.
In addition, since the said evaluation becomes substantially the same as the structure which formed the touch panel using the transparent electrode of this invention in the liquid crystal panel surface, it becomes equivalent to having evaluated about the use for the touch panel use of the transparent electrode of this invention. .

  The film of the present invention can be suitably used, for example, as a base film of a transparent electrode used together with a liquid crystal display device, particularly as a base film of a transparent electrode of a touch panel, in order to exhibit an excellent interference spot suppressing effect. Moreover, since it is excellent also in adhesiveness with the polarizer which consists of PVA, the transparent electrode obtained using the film of this invention can also be used as a polarizer protective film as it is, and the film which comprises a display by doing so Reduction, transparency improvement, weight reduction, cost reduction, and the like. Therefore, the industrial applicability is high.

Claims (8)

A film having a polyester film and an easy adhesion layer provided on one side thereof,
The in-plane retardation of the polyester film is 7000 nm or more, the thickness is 5 to 250 μm,
The easy-adhesion layer contains a binder component composed of a thermoplastic resin as a main component, and the surface wetting index is 60 mN / m or more.
Transparent electrode film.   The binder component of the easy-adhesion layer is composed of 40 to 90% by mass of a copolyester based on the mass of the binder component and 10 to 60% by mass of polyvinyl alcohol based on the mass of the binder component. Transparent electrode film.   The film for transparent electrodes according to claim 1 or 2, wherein the polyester film contains 0.1 to 10% by mass of an ultraviolet absorber based on the mass of the polyester film. The film for transparent electrodes according to claim 3, wherein the ultraviolet absorber is an ultraviolet absorber represented by the following general formula (1).

(However, in the above general formula (1), Ar represents an n-valent biphenyl residue. The biphenyl residue may have a substituent. The ring bonded to Ar may be any arbitrary ring. Xa, Xb, and Xc each independently represent a hetero atom, and Xa, Xb, and Xc may have a substituent, and R is 1. Represents a valent hydrocarbon group, m represents an integer of 0 to 4, and n represents an integer of 1 to 4.)   The film for transparent electrodes of any one of Claims 1-4 which has a hard-coat layer in the surface on the opposite side to the said easily bonding layer.   The transparent electrode film according to claim 1, wherein a hard coat layer is provided on a surface opposite to the easy adhesion layer or a surface opposite to the easy adhesion layer. A transparent electrode provided with a transparent conductive layer.   The transparent electrode according to claim 6, comprising a polarizer made of polyvinyl alcohol on the easy-adhesion layer.   The transparent electrode according to claim 6 or 7, which is for a touch panel used together with a liquid crystal display device.