JPH08267689A - Transparent laminated film - Google Patents

Abstract

PURPOSE: To provide a transparent laminated film which has excellent optical properties to be sufficiently applied to a liquid crystal display element. CONSTITUTION: A protective layer having solvent resistance is provided at least on one surface of a polymer film, and formed of cured resin of epoxy cured resin. The transparent laminated film has high solvent resistance for simultaneously satisfying organic solvent resistance, alkali resistance and etchant liquid resistance which are required for various applications, small load for the steps, and can be sufficiently applied to an electrode board for various display or particularly a liquid crystal display element in which requirements are severe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent laminated film having excellent solvent resistance and transparency, and more particularly to optical applications, particularly for transparent substrates such as liquid crystal display panels, touch panels and flat lighting panels, and transparent electrode substrates. The present invention relates to a suitable transparent laminated film.

[0002]

2. Description of the Related Art In recent years, in addition to the demands for lighter and thinner and larger size members for liquid crystal display devices, long-term reliability,
There are high demands on the degree of freedom of shape and curved surface display. In particular, as the use of portable and mobile devices such as pagers (pagers), mobile phones, electronic organizers, and pen input devices becomes widespread, these transparent substrates and transparent electrode substrates are thick, heavy, and cracked. Transparent substrates and transparent electrode substrates using a plastic film as a substrate have been studied in place of the easy glass substrate, and some of them have been put into practical use.

However, this plastic film substrate is generally inferior in solvent resistance to the glass substrate.
By the way, the transparent electrode substrate of a plastic film provided with a transparent conductive layer, when used in the above liquid crystal display panel or the like, an acidic aqueous solution for etching the transparent conductive layer, an alkaline liquid for dissolving the resist after patterning, and depending on the application. It will be exposed to an organic solvent when the alignment film is formed. At this time, the plastic film may be swollen or whitened and may be further dissolved, so that it cannot be used as an electrode substrate.

As a concrete proposal for improving this problem,
It has been proposed to provide a plastic film with a protective layer having solvent resistance. For example, JP-A-64-500
No. 22, etc. propose to provide a resin layer for crosslinking a phenoxyether type resin with an isocyanate group or the like by a coating method, but the solvent resistance is not sufficiently satisfied. Further, Japanese Patent Laid-Open No. 5-313150 proposes to provide an active energy ray curable resin layer, but a release film is required at the time of curing, which causes difficulty in the process.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above problems and has sufficient solvent resistance, specifically, organic solvent resistance, alkali resistance and etching solution resistance required for various applications. To provide a transparent laminated film having high solvent resistance, satisfying all of the requirements at the same time, having a small load on the process, and being sufficiently applicable to various display electrode substrates, particularly to liquid crystal display elements that are particularly demanding. The purpose is to

[0006]

The above object can be achieved by the present invention described below. That is, the present invention is a transparent laminated film in which a protective layer having solvent resistance is provided on at least one surface of a polymer film, wherein the protective layer comprises a cured product of a novolac type epoxy curable resin. It is a transparent laminated film.

According to the present invention described above, a layer composed of a cured product of a novolac type epoxy curable resin among epoxy resins has a high resistance to the above-mentioned organic solvent resistance, alkali resistance and etching solution resistance at the same time. It was made by finding that it has a solvent property and sufficient optical characteristics.

The present invention will be described in detail below. In the present invention, having solvent resistance means that when a polymer film substrate provided with a transparent conductive layer is applied to an electrode substrate for various displays, the substrate is an acidic aqueous solution for etching the transparent conductive layer, and a resist is used after patterning. It means that when exposed to an alkaline liquid for dissolution and, depending on the application, various solvents such as an organic solvent during preparation of the alignment film, it does not swell, whiten or dissolve, and does not pass these solvents. That is, when exposed to the solvent by providing a layer having solvent resistance, the layer having solvent resistance does not swell or whiten or dissolve, and does not penetrate the solvent, and a polymer film serving as a substrate is formed. Protecting against swelling, whitening and dissolution by a solvent.

As described above, the present invention is characterized by using a novolac type epoxy-based curable resin for the solvent-resistant protective layer provided on the polymer film.

Of these, a novolac type epoxy resin represented by the following structural formula is preferably applied from the viewpoint of solvent resistance.

[0011]

Embedded image

Here, R ¹ is H or CH ₃ , and R ² is H.
Or a glycidyl phenyl ether group, n is 1 to 50
Indicates an integer. Note that n generally has a distribution,
Although a certain number cannot be specified, the average number is preferably large, preferably 3 or more, more preferably 5 or more.

As the curing agent for curing the above epoxy resin, known ones can be applied. For example, curing agents such as amine-based, polyaminoamide-based, acids and acid anhydrides, imidazole, mercaptan, and phenol resin are used.

Among them, as the curing agent for curing the above-mentioned novolac type epoxy resin, an acid anhydride, a polymer containing an acid anhydride structure, or an alicyclic amine is particularly preferable in view of solvent resistance, optical characteristics, thermal characteristics and the like. It is preferably used, more preferably an acid anhydride or a polymer containing an acid anhydride structure. Examples of the acid anhydride include methylhexahydrophthalic anhydride, alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride, aromatic acid anhydrides such as phthalic anhydride, and aliphatic acid anhydrides such as dodecenylsuccinic anhydride. Among them, methylhexahydrophthalic anhydride is preferably used. Examples of the polymer having an acid anhydride structure include maleic anhydride copolymers, and styrene-maleic anhydride copolymers and isobutylene-maleic anhydride copolymers are preferably used. The polymer having an acid anhydride structure may be used alone or as a mixture with an acid anhydride. Bis (4-amino-3-methyldicyclohexyl) methane as an alicyclic amine,
Examples thereof include diaminodicyclohexylmethane and isophoronediamine, and bis (4-amino-3-methyldicyclohexyl) methane is preferably used.

When an acid anhydride or a polymer containing an acid anhydride structure is used as a curing agent, it is preferable to add an appropriate amount of a known curing catalyst such as a tertiary amine or imidazole in order to increase the reaction rate.

Means for providing this epoxy resin layer include wet coating methods such as the Mayer bar coating method, the gravure roll coating method, the spin coating method, the dipping method, the laminate coating method, etc., but the uniform film thickness is obtained. The wet coating method is preferably used because it is easy to control. In addition, at the time of coating, dilution with a solvent is possible for the purpose of adjusting the pot life and viscosity of the epoxy resin. As the solvent, any solvent capable of uniformly dissolving epoxy, such as ketones and ether esters, may be used, and an appropriate amount can be added according to the purpose.

The coated epoxy resin layer is cured by heat treatment at a temperature not higher than the glass transition temperature of the polymer film to form a cured resin layer having solvent resistance.

The thickness of the epoxy-based curable resin layer is preferably 0.1 μm or more and 30 μm or less in terms of the thickness after curing, and is 0.1.
It is more preferably 3 μm or more and 20 μm or less. If it is less than 0.1 μm, the effect as a solvent resistant layer becomes insufficient,
If it exceeds μm, the flexibility required for processing, assembly, etc. becomes insufficient, which is not suitable for practical use.

When the transparent laminated film may be dipped in a solvent, it is desirable to provide the above protective layers on both sides of the polymer film.

The transparent laminated film provided with this protective layer is
Considering optical applications that require a high degree of optical characteristics such as when used in a display panel such as a liquid crystal display panel, the retardation value is 20 nm or less, and the light transmittance at a wavelength of 550 nm is 80% or more. preferable.

Here, the retardation value is a product Δn · d of the known difference Δn in birefringence refractive index and the film thickness d, and it depends on the measurement wavelength, but the measurement value at the measurement wavelength of 590 nm is Use as a representative value. When the retardation value exceeds 20 nm, it causes coloring especially when used as a liquid crystal display device. On the other hand, when the light transmittance is less than 80%, the transparency as an electrode substrate for various displays becomes insufficient.

The polymer film in the present invention includes
Known transparent polymer films such as polyester, polycarbonate, polyarylate, polysulfone, and polyethersulfone are applied, but when the above optical applications are included, the retardation value is 20 nm or less, and at a wavelength of 550 nm. An optically isotropic polymer film having a light transmittance of 85% or more is preferable.

In general, a polymer film is prepared by a melt extrusion method in which a raw material polymer material is thermally melted and extruded from a die to form a film, or the polymer material is dissolved in a solvent and poured onto a support. It can be obtained by a solution casting method of rolling and heating to evaporate the solvent to form a film, but the solution casting method is preferably used to achieve the retardation. In the melt extrusion method, it is not only difficult to obtain a film with low retardation, but die lines, gelation products, fish eyes, etc. are likely to occur in the film, and it is possible to obtain a film with uniform optical properties over a wide area. difficult.

Examples of the polymer material for the above-mentioned optically isotropic polymer film include amorphous polymer materials such as polycarbonate, polyarylate, polyether sulfone and polysulfone. From the viewpoint, polycarbonate or polyarylate is particularly preferably used.

Polycarbonate is 2,2-bis (4-
A main component is hydroxyphenyl) propane, and a copolymerization component may be included for improving optical characteristics and heat resistance. Examples of the copolymerization component include bis (4-oxyphenyl) methane, 1,1-bis (4-oxyphenyl) ethane, 1,1-bis (4-oxyphenyl) butane, 2,
2-bis (4-oxyphenyl) butane, 1,1-cyclohexylene, 9,9-bis (4-hydroxyphenyl) fluorene, 1,1-bis (4-hydroxyphenyl) 3,3,5-trimethylcyclohexane Etc.

Polyarylate contains 2,2-bis (4-hydroxyphenyl) propane component as a main component as a diol component, and terephthalic acid and isophthalic acid as a main component as dicarboxylic acid components.

For the production of these films, as described above, the above-mentioned solution casting method in which polycarbonate or polyarylate is dissolved in a solvent and cast on a support is preferably applied. As the solvent for forming the film, any solvent that basically dissolves polycarbonate or polyarylate can be applied, but methylene chloride or the like is preferably used. The concentration of the raw material polymer in the solution for film formation is 6% by weight.
The amount is preferably 30% by weight or less. If it exceeds 30% by weight, uniform dissolution and storage stability of the solution are poor, and if it is less than 6% by weight, the effective viscosity is low and it is not preferable in practice.

By the way, when a polymer film is used for a transparent electrode substrate of a liquid crystal display panel or the like, a gas barrier property is required. That is, the polymer film generally has gas permeability as compared with the glass substrate, and the permeated gas becomes bubbles in the liquid crystal part, which causes a display defect. Therefore, a layer that prevents gas permeation, that is, a gas barrier layer is required. Therefore, when the above-mentioned transparent laminated film of the present invention is also applied to these applications, it is preferable to provide a gas barrier layer.

As the gas barrier layer, known materials can be applied, for example, polyvinyl alcohol, polyvinyl alcohol-ethylene copolymer, polyvinylidene chloride and its copolymer weight, which are known as polymers having gas barrier properties. Coalescence, polyacrylonitrile and its copolymer, etc. can be applied. Among them, polyvinyl alcohol and polyvinyl alcohol-ethylene copolymer are preferable from the viewpoint of gas generated during incineration.

This gas barrier layer is formed by the wet coating method described for the protective layer. For example, the gas barrier layer of polyvinyl alcohol or polyvinyl alcohol-ethylene copolymer is a known solvent, that is, polyvinyl alcohol is dissolved in water, polyvinyl alcohol-ethylene copolymer is dissolved in a mixed solvent of water and propyl alcohol, It is formed by coating a polymer film by a coating method and removing the solvent by a drying treatment at a temperature not higher than the glass transition temperature of the polymer film.

The thickness of the gas barrier layer varies depending on the required gas barrier performance, but is usually 0.1 μm or more and 50 or more.
μm or less, and when used in a liquid crystal display device, 25
At least 1 cc / (m ² · day · a
A gas barrier property of tm) or less is required.

When used in the transparent laminated film of the present invention, this gas barrier layer is preferably provided between the polymer film and the epoxy type curable resin layer of the protective layer from the viewpoint of solvent resistance.

In this structure, when the adhesiveness between the polymer film and the gas barrier layer is required, an anchor coat layer is provided between them if necessary. A commercially available urethane adhesive or the like can be used as the anchor coat layer.

Also, when adhesiveness between the epoxy curable resin layers of the gas barrier layer and the protective layer is required, an anchor coat layer is provided between these layers, if necessary. As the anchor coat layer, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, a so-called silane coupling agent, or an isocyanate such as an adduct of trimethylolpropane of tolylene diisocyanate is preferable. Isocyanates are preferred. Isocyanates may be used alone,
It is more preferable to mix a phenoxy resin, a phenoxy ether resin, a polyol, an acrylic polyol, or the like.

The protective layer of the present invention contains a suitable amount of a so-called silane coupling agent such as γ-aminopropyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane before being applied to the epoxy-based curable resin. By mixing, the adhesiveness can be improved, and even if the anchor coat layer is not provided, it can be dealt with in some cases.

Further, by providing a transparent conductive layer on the surface of the laminated film of the present invention having the above constitution, a transparent conductive laminated film suitable for a transparent electrode of a liquid crystal display panel, a touch panel or the like can be obtained.

As the transparent conductive layer, known metals such as tin, indium, titanium and the like or oxides thereof can be applied, but among them, those comprising indium oxide containing 5 to 15% by weight of tin are preferable. The thickness of the transparent conductive layer is 2
The range of 0 to 200 nm is preferable in terms of transparency, conductivity, flexibility and the like.

Examples of the present invention will be described below together with comparative examples.

[0039]

EXAMPLES Various physical properties of Examples and Comparative Examples were measured as follows.

(1) Solvent resistance (a) Organic solvent resistance It was immersed in N-methylpyrrolidone at 80 ° C. for 3 minutes, and the change in appearance was visually observed. (B) Alkali resistance It was immersed in a 3.5 wt% NaOH aqueous solution at 25 ° C. for 10 minutes, thoroughly washed with running water, dried and weighed, and the weight difference before and after immersion was judged. (C) Resistance to etching liquid: Immerse in a liquid in which 35% ferric chloride aqueous solution, 35% hydrochloric acid, and water are mixed at a weight ratio of 1: 1: 10 for 10 minutes at 25 ° C. and thoroughly rinse with running water. After that, it was dried and weighed, and the weight difference was measured before and after the immersion.

(2) Light Transmittance Using U-3500 manufactured by Hitachi, Ltd., a wavelength of 550
An integrated sphere type light transmittance measurement of nm was performed.

(3) Retardation measurement Multi-wavelength birefringence measuring device M-15 manufactured by JASCO Corporation
0 was used for measurement at a wavelength of 590 nm.

(4) Oxygen permeability measurement 25 using Oxytran 2 / 20MH manufactured by MOCON
It was measured at ° C.

Example 1 As a polymer film for a substrate, a polycarbonate film was prepared by the solution casting method as follows.

After dissolving 20 parts by weight of a polycarbonate resin (specifically, C-1400 manufactured by Teijin Kasei Co., Ltd.) in 80 parts by weight of methylene chloride, it is cast on a glass plate with an applicator and then dried. It was placed inside and gradually heated from room temperature. When the residual solvent reaches 13% by weight, peel it off from the glass plate and
It was dried at 0 ° C. until the residual solvent amount became 0.1% by weight or less to obtain a polycarbonate film. The thickness of this film was 98 μm.

An anchor coat layer was formed on one surface of this polycarbonate film. The anchor coat layer is made of polyurethane resin. Specifically, 100 parts by weight of A310 manufactured by Takeda Pharmaceutical Co., Ltd. is used as the polyol component of the main agent, and 2 parts of A3 manufactured by the same company is used as the isocyanate component of the curing agent.
After mixing 5 parts by weight, coat with a Meyer bar and apply 1 at 80 ° C.
It was further formed by heat treatment at 130 ° C. for 5 minutes.

Next, a gas barrier layer was laminated on this anchor coat layer. The gas barrier layer is made of polyvinyl alcohol (specifically, PVA-11 manufactured by Kuraray Co., Ltd.).
7) 10 parts by weight was uniformly dissolved in 90 parts by weight of water as a solvent, and the solution was applied with a Meyer bar and heat-treated at 110 ° C. for 5 minutes to form a film. The thickness of the gas barrier layer is 3μ
It was m. The film having this structure will be referred to as a polymer film with a gas barrier layer.

A protective layer was laminated on the polymer film with the gas barrier layer as follows to obtain a transparent laminated film. The protective layer is a cresol novolac type epoxy resin (specifically, EOCN-104 manufactured by Nippon Kayaku Co., Ltd.).
S) 100 parts by weight are dissolved in 150 parts by weight of methyl isobutyl ketone to give methyl hexahydrophthalic anhydride 74
1 part by weight and 5 parts by weight of 1,8-diazabicyclo (5,4,0) undecene were added and uniformly mixed to obtain a Mayer bar.
And heat treatment at 100 ° C. for 3 minutes, and then apply the same on the other side of the polymer film with a gas barrier layer in the same manner with a Meyer bar and heat-treat at 100 ° C. for 3 minutes. Further, heat treatment was performed at 135 ° C. for 30 minutes to form both surfaces. The protective layers each had a thickness of 8 μm.

The obtained transparent laminated film had a retardation of 10 nm, a light transmittance of 89.5% and an oxygen transmittance of 0.15 cc / (m ² · day · atm), and had no problem with solvent resistance. It was a transparent laminated film having excellent optical properties, gas barrier properties and solvent resistance.

Example 2 A protective layer was laminated on the polymer film with a gas barrier layer obtained in Example 1 as follows to obtain a transparent laminated film.

The protective layer is a cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.) 10
0 parts by weight was dissolved in 150 parts by weight of methyl isobutyl ketone, and 27.5 parts by weight of bis (4-amino-3-methyldicyclohexyl) methane and 1 part by weight of γ-glycidoxypropyltrimethoxysilane were added to homogeneity. The mixture is applied on one side of the polymer film with a gas barrier layer with a Meyer bar, heat-treated at 80 ° C for 60 minutes, and the same is applied on the other side with a Meyer bar in the same manner. After heat treatment at 80 ℃ for 60 minutes, further at 135 ℃ 1
It was formed on both sides by heat treatment for 80 minutes.

The obtained transparent laminated film had a retardation of 10 nm, a light transmittance of 89%, an oxygen transmittance of 0.15 cc / (m ² · day · atm), no solvent resistance and no optical problem. It was a transparent laminated film having excellent properties, gas barrier properties and solvent resistance.

Example 3 As a polymer film for a substrate, a polyarylate film was prepared by the solution casting method as follows.

Polyarylate (U-produced by Unitika Ltd.)
After dissolving 23 parts by weight of 100) in 77 parts by weight of methylene chloride, the mixture was cast on a glass plate with an applicator, then placed in a dryer and gradually heated from room temperature. When the residual solvent was 15% by weight, it was peeled from the glass plate and dried at 120 ° C. while balancing the vertical and horizontal tensions until the residual solvent amount became 0.08% by weight to obtain a polyarylate film. The thickness of this film was 101 μm.

The same anchor coat layer, gas barrier layer and protective layer as those in Example 1 were laminated on this polyarylate film in the same manner as in Example 1.

The transparent laminated film thus obtained had a retardation of 11 nm, a light transmittance of 87%, an oxygen transmittance of 0.1 cc / (m ² · day · atm), no solvent resistance and no optical problem. It was a transparent laminated film having excellent properties, gas barrier properties and solvent resistance.

[Example 4] A protective layer was laminated on the polymer film with a gas barrier layer obtained in Example 1 as follows to obtain a transparent laminated film.

The protective layer is made of phenol novolac type epoxy resin (EPPN-201 manufactured by Nippon Kayaku Co., Ltd.) 100.
By mixing 150 parts by weight of methyl isobutyl ketone with 90 parts by weight of methylhexahydrophthalic anhydride and 5 parts by weight of 1,8-diazabicyclo (5,4,0) undecene, a uniform mixture is prepared. Apply to one side of the polymer film with gas barrier layer with a bar, heat treatment at 100 ° C for 3 minutes, and apply the same to the other side of the polymer film with gas barrier layer in the same manner as a Mayer bar. Was applied and heat-treated at 100 ° C. for 3 minutes, and then heat-treated at 135 ° C. for 30 minutes to form both surfaces. The protective layers each had a thickness of 8 μm.

The transparent laminated film thus obtained had a retardation of 10 nm, a light transmittance of 90%, an oxygen transmittance of 0.15 cc / (m ² · day · atm), no solvent resistance, and an optical property. It was a transparent laminated film having excellent properties, gas barrier properties and solvent resistance.

Example 5 A protective layer was laminated on the polymer film with a gas barrier layer obtained in Example 1 as follows to obtain a transparent laminated film.

The protective layer is a cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.) 10
0 parts by weight was dissolved in 100 parts of methyl isobutyl ketone, and further 30 parts by weight of methylhexahydrophthalic anhydride,
5 parts by weight of 1,8-diazabicyclo (5,4,0) undecene were added and mixed uniformly, and 50 parts by weight of styrene-maleic anhydride copolymer (SMA-1000 manufactured by Elf Atchem Japan Co., Ltd.) was added to methyl isobutyl. A coating solution prepared by uniformly dissolving 50 parts by weight of ketone was applied with a Meyer bar, heat-treated at 100 ° C. for 3 minutes, and the same was applied to the other side of the polymer film with a gas barrier layer. Was coated with a Meyer bar in the same manner, heat-treated at 100 ° C. for 3 minutes, and further heat-treated at 135 ° C. for 30 minutes to laminate both surfaces. The thickness of the protective layer is
Each was 8 μm.

The obtained transparent laminated film had a retardation of 10 nm, a light transmittance of 89.5% and an oxygen transmittance of 0.15 cc / (m ² · day · atm), and had no problem with solvent resistance. It was a transparent laminated film having excellent optical properties, gas barrier properties and solvent resistance.

[Example 6] Only the protective layer was directly laminated on the polycarbonate film obtained in Example 1 as described below to obtain a transparent laminated film having a simple structure and suitable for use in which gas barrier property is unnecessary.

The protective layer is a cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.) 10
0 parts by weight was dissolved in 150 parts by weight of methyl isobutyl ketone to obtain 74 parts by weight of methyl hexahydrophthalic anhydride,
A mixture of 5 parts by weight of 1,8-diazabicyclo (5,4,0) undecene and a uniform mixture was applied to one side of a polycarbonate film with a Meyer bar and heat-treated at 100 ° C. for 3 minutes, and then another The same thing was similarly coated on one surface with a Meyer bar, heat-treated at 100 ° C. for 3 minutes, and then heat-treated at 135 ° C. for 60 minutes to form both surfaces. The protective layers each had a thickness of 8 μm.

The obtained transparent laminated film had a retardation of 10 nm, a light transmittance of 90%, solvent resistance without problems, and excellent optical characteristics and solvent resistance.

Further, an indium-tin oxide layer was formed as a transparent conductive layer on one surface by a sputtering method. As the sputtering target, a target having a composition of indium / tin = 90/10 by weight and a packing density of 90% was used. The obtained transparent laminated film with a transparent conductive layer was suitable for a transparent electrode substrate such as a transparent touch panel.

[Comparative Example 1] A protective layer was laminated on the polymer film with a gas barrier layer obtained in Example 1 as follows to obtain a transparent laminated film.

For the protective layer, 40 parts by weight of a phenoxy resin (YP-50 manufactured by Tohto Kasei Co., Ltd.) was dissolved in 60 parts by weight of methyl ethyl ketone, and 40 parts by weight of A3 manufactured by Takeda Pharmaceutical Co., Ltd. was added as an isocyanate and mixed uniformly. What was done was coated on one side of the polymer film with a gas barrier layer with a Meyer bar, heat-treated at 80 ° C for 4 minutes, and the same on the other side with the Meyer bar. Heat treatment at 80 ℃ for 4 minutes, then at 135 ℃ for 20 minutes
It was formed on both sides by heat treatment for minutes. The protective layers each had a thickness of 8 μm.

The obtained transparent laminated film had a retardation of 11 nm, a light transmittance of 90% and an oxygen transmittance of 0.15 cc / (m ² · day · atm). , The swelling of the transparent laminated film is severe,
The shape was not retained and the resistance to organic solvents was poor.

The above results are summarized in Table 1.

[0071]

[Table 1]

[0072]

INDUSTRIAL APPLICABILITY The present invention has a solvent-resistant protective layer formed of a novolac type epoxy resin and has excellent solvent resistance which simultaneously satisfies organic solvent resistance, alkali resistance and etching solution resistance. Further, it realizes a transparent laminated film having good optical characteristics, and can be widely applied to a display device such as a liquid crystal display panel, a transparent substrate such as a touch panel, a transparent electrode substrate and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Fujishima 4-32 Asahigaoka, Hino City, Tokyo Teijin Limited Tokyo Research Center

Claims (5)

[Claims] 1. A transparent laminated film in which a protective layer having solvent resistance is provided on at least one surface of a polymer film, wherein the protective layer comprises a cured product of a novolac type epoxy curable resin. A transparent laminated film. 2. The transparent laminated film according to claim 1, wherein the epoxy curable resin is a novolac type epoxy resin represented by the following structural formula. Embedded image (In the above formula, R ¹ is H or CH ₃ , R ² is H or a glycidyl phenyl ether group, and n is an integer of 1 to 50.) 3. The transparent laminated film according to claim 1, wherein the curing agent for the epoxy curable resin is an acid anhydride or a polymer having an acid anhydride structure. 4. The retardation value of the laminated film is 2.
0 nm or less and a light transmittance of 8 at a wavelength of 550 nm.
It is 0% or more, The transparent laminated film in any one of Claims 1-3. 5. The polymer film is polycarbonate.
The transparent laminated film according to claim 4, which is a transparent film or a polyarylate film.