JPH0664103A - Optical laminated sheet and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an optical laminated sheet having extremely excellent surface smoothness, and to provide a method in which such an optical laminated sheet is manufactured industrially advantageously. CONSTITUTION:The clearance of an optical isotropic sheet 1 having a thermal crosslinking resin layer as a surface layer and a smoothed mold material 3 with a smooth surface is supplied with the resin liquid 2a of an activation-energy ray curable type resin composition and this resin liquid 2a is held between both sheet and mold material in a stratiform shape, and the held layer 2b is cured by the irradiation of activation energy rays, thus forming an activation- energy ray curable type resin cured layer 2. A biaxially oriented polyethylene terephthalate film, which has surface roughness of 0.004mum and in which no corona discharge is generated, is employed as the smoothed mold material 3. Accordingly, the surface roughness of the free surface of the actinic ray curable type resin cured layer 2 reaches 0.1mum or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical laminated sheet having an extremely excellent surface smoothness, and particularly to an optical laminated sheet suitable for an electrode substrate for manufacturing a liquid crystal display panel. It also relates to a method for industrially producing such an optical laminated sheet.

[0002]

2. Description of the Related Art Conventionally, glass has been used as a substrate for transparent electrodes for liquid crystal displays, but it cannot be made thin.
Due to problems such as inferior impact resistance and difficulty in mass production, plastic substrates have recently been used more frequently, and the applicant has also filed several applications as described below. There is. The crosslinked resin cured product layer in these applications means a thermally crosslinkable resin layer.

For example, in Japanese Patent Laid-Open No. 63-71829, an aqueous anchor coat layer is provided on at least one side of a base material layer made of a sheet of polycarbonate resin or the like and having a retardation value of 30 nm or less. An electrode substrate for a liquid crystal display panel, in which a single-layer or multi-layer protective layer made of a gas permeable resin or / and a crosslinked resin cured product is provided on the above.

In JP-A-64-50021, a laminate of an air-permeable synthetic resin film layer and a crosslinkable resin cured product layer is adhered to each other with their respective air-permeable synthetic resin film layer surfaces facing each other. An electrode substrate for a liquid crystal display panel is shown, which has a structure in which it is laminated and integrated via an agent layer.

In JP-A-64-50022, a cross-linking agent capable of reacting with the gas-permeable synthetic resin film layer is used on both sides of the gas-permeable synthetic resin film layer formed by a casting method. A method for producing an electrode substrate for a liquid crystal display panel, in which the cured crosslinkable resin layer is directly formed by a casting method, is disclosed.

JP-A-2-137922 discloses a retardation value of 30 having a resin layer having no solvent resistance.
For manufacturing liquid crystal display panels, in which an alcohol-soluble UV-curable adhesive layer or a water-based thermosetting adhesive layer is laminated on the resin layer side of the base sheet having a thickness of nm or less, and a release sheet is further laminated on the adhesive layer. Is shown as an example of a base sheet, and a sheet having a layer structure of a resin sheet such as polycarbonate / anchor coating layer / air-permeable synthetic resin layer / phenoxyether-based crosslinked polymer layer is shown as an example of the base sheet. I have been given.

In Japanese Patent Laid-Open No. 149819/1990, the electrode support film side of an electrode support film with a transparent electrode having a structure in which a transparent electrode is provided on one surface of an electrode support film that can be wound in a roll is referred to as a retardation value. Shows a liquid crystal cell substrate with a transparent electrode laminated and integrated on a base material having a light transmittance of 80 nm or less and a light transmittance of 60% or more. As an example of the electrode supporting film, a resin film layer / anchor coating layer / crosslinking is shown. Cured resin layer, resin film layer / anchor coating layer / air permeable synthetic resin film layer / crosslinkable resin cured material layer, crosslinkable resin cured material layer / air permeable synthetic resin film layer / anchor coating layer / resin film Layer / anchor coating layer / air-permeable synthetic resin film layer / crosslinkable resin cured product layer, crosslinkable resin cured product layer / air-permeable synthetic resin layer Film having a layer structure such as a film layer / adhesive layer / penetration resistance temper synthetic resin film layer / crosslinkable resin cured material layer is raised.

[0008]

When the above-mentioned sheet-like substrate is used as an electrode substrate for manufacturing a liquid crystal display panel, a transparent electrode such as ITO is formed on the cured crosslinkable resin layer, and further thereon. After the alignment film is provided on, the liquid crystal cell is assembled. In this case, the liquid crystal that can be contained between the substrates is TN.
In the case of (twisted nematic) liquid crystal, some irregularities on the substrate surface on the transparent electrode forming side have almost no effect on product quality. This is because the liquid crystal display panel assembled from the liquid crystal cell using the TN liquid crystal has an achromatic color, and if the light and shade are clear, the panel is acceptable.

However, when the liquid crystal contained between the substrates is STN (super twisted nematic) liquid crystal, the STN liquid crystal has a gap of, for example, about 270 ° although the gap between the substrates is only about 5 to 6 μm. Due to the twisting, even if there is a slight unevenness on the substrate surface on the transparent electrode formation side, the display is colored purple, green, etc. and the screen becomes very difficult to see. It was the biggest weakness of the LCD panel. The electrode substrate according to the applicant's application cited above has not sufficiently solved this problem.

Under such a background, the present invention provides an optical laminated sheet having an extremely excellent surface smoothness, particularly an optical laminated sheet suitable for an electrode substrate for producing a liquid crystal display panel, and the same. It is an object of the present invention to provide a method for industrially producing such an optical laminated sheet.

[0011]

The optical laminated sheet of the present invention comprises a single or multi-layered optically isotropic sheet (1) having at least a surface layer of a thermally crosslinkable resin layer, either directly or on an anchor coating layer. A layered sheet provided with an active energy ray-curable resin cured layer (2) via the above, wherein the surface roughness of the free surface of the active energy ray-curable resin cured layer (2) is 0.5.
The retardation value of the entire laminated sheet is 60 nm or less, and the visible light transmittance is 60% or more.

The method for producing the optical laminated sheet of the present invention is as follows:
At least a surface layer is a heat-crosslinkable resin layer is a single-layer or multi-layer sheet, an optical isotropic sheet with or without anchor coating layer (1) and a smoothing template material (3) having a smooth surface; The resin liquid (2a) of the active energy ray-curable resin composition is supplied to the gap so that the resin liquid (2a) is sandwiched between the two layers, and then the sandwiching layer ((a) is irradiated by irradiation with active energy rays. 2b) is cured to form an active energy ray curable resin cured layer (2).

The present invention will be described in detail below. The terms "sheet", "film", and "layer" all mean thin layers, and do not limit the thickness.

As the optically isotropic sheet (1), a single-layer or multiple-layer optically isotropic sheet in which at least the surface layer is a thermally crosslinkable resin layer is used.

Among the above, examples of the thermally crosslinkable resin in the thermally crosslinkable resin layer include phenoxy ether type crosslinkable resin, epoxy resin, acrylic resin, acrylic epoxy resin, melamine resin, phenol resin or urethane resin.

Among the crosslinkable resins, a particularly preferable resin is a phenoxy ether type polymer represented by the following chemical formula 1.

[0017]

[Chemical 1]

(Wherein R ^{1 to} R ⁶ are each hydrogen, a lower alkyl group having 1 to 3 carbon atoms or Br, R ⁷ is a lower alkylene group having 2 to 4 carbon atoms, m is an integer of 0 to 3, n is 2
It means an integer of 0 to 300, respectively. )

A phenoxyether-type crosslinked polymer is obtained by subjecting the hydrogen portion of the hydroxyl group of this polymer to a crosslinking reaction with a polyfunctional compound as a crosslinking agent. As the cross-linking agent (polyfunctional compound) reacted to obtain a cross-linked polymer, a group having a high reaction activity with a hydroxyl group, for example, an isocyanate group,
A compound having two or more carboxyl groups, reactive induction groups in the carboxyl group (for example, halide, active amide, active ester, acid anhydride group, etc.), mercapto and the like are used, and polyisocyanate is particularly important. .

Among the above, the acrylic resin is at least 3 or more acryloyloxy groups or // in the molecule.
And a composition containing a polyfunctional unsaturated monomer containing a compound containing a methacryloyloxy group (hereinafter referred to as a compound containing a polyfunctional (meth) acryloyloxy group) as a main component and / or an initial radical reactant thereof as a main component I can give you things. Particularly preferred is a polyfunctional unsaturated monomer containing at least 3 or more (meth) acryloyloxy groups in the molecule, in an amount of 50% by weight or more, preferably 70% by weight, based on all unsaturated monomers. , Particularly preferably 90
It is a composition comprising an unsaturated monomer mixture or / and an initial radical reaction product thereof, which is contained in an amount of at least wt%.

Examples of layers other than the thermally crosslinkable resin layer constituting the optically isotropic sheet (1) include a base material layer and a gas permeable resin layer. Examples of the layer structure of the optically isotropic sheet (1) are a heat-crosslinkable resin layer / base material layer, a heat-crosslinkable resin layer / air-permeable resin layer / base material layer, a heat-crosslinkable resin layer / air-permeable resistance. Resin layer / base material layer /
Air-permeable resin layer / heat-crosslinkable resin layer, heat-crosslinkable resin layer / air-permeable resin layer / base material layer / air-permeable resin layer, heat-crosslinkable resin layer / air-permeable resin layer / air-permeable resin Layer / heat-crosslinkable resin layer. In the case of a laminated structure, an anchor coating layer or an adhesive layer can be provided between the layers. An anchor coating layer may be provided on the surface of the thermally crosslinkable resin layer constituting the surface layer of the optically isotropic sheet (1), if necessary.

Among the above, as the base material layer, polycarbonate, polymethylmethacrylate, polyethersulfone, polysulfone, polyarylate, amorphous polyolefin, polyparabanic acid resin, polyamide or the like is used.

The substrate layer preferably has a heat distortion temperature of 80 ° C. or higher. The base material layer is obtained by a casting method or an extrusion method,
The thickness is often about 30 μm to 3 mm.

The air-permeable resin constituting the air-permeable resin layer includes, for example, a layer formed from a polymer containing 50 mol% or more of an acrylonitrile component, a vinyl alcohol component or a vinylidene halide component. Polymers having a hydroxyl group are important, such as polyvinyl alcohol or copolymer modified products or graft products thereof, and ethylene-vinyl alcohol copolymers having an ethylene content of 15 to 50 mol%.

The air-permeable resin layer is usually formed by a casting method, and its oxygen permeability (measured according to ASTM D-1434-75) is 30 cc / 24 hr · m ² · atm or less, especially 20 cc / 24 hr · m ² ·
Atm or less, more preferably 10 cc / 24 hr · m ² · atm or less. The thickness of the air-permeable resin layer is 1 to 50 μm
In particular, it is suitable to set in the range of 2 to 20 μm.

As the active energy ray-curable resin constituting the active energy ray-curable resin cured layer (2), a prepolymer or / and a monomer having photopolymerizability, and optionally other monofunctional or polyfunctional monomer, Various polymers,
A resin composition containing a photopolymerization initiator and a sensitizer is used.

Examples of the photopolymerizable prepolymer include polyester acrylate, polyester urethane acrylate, epoxy acrylate and polyol acrylate, and examples of the photopolymerizable monomer include monofunctional acrylate, bifunctional acrylate and trifunctional or higher functional acrylate. Are exemplified. Of these, epoxy acrylates, which have good physical properties after curing, are particularly useful, so it is desirable to use at least part of them.

As the photopolymerizable prepolymer or monomer, in addition to the above, the phosphazene resin represented by the following chemical formula 2 is also preferably used.

[0029]

[Chemical 2]

When the active energy ray-curable resin is an ultraviolet-curable resin, a small amount of a photoinitiator or a sensitizer is usually used in combination, but depending on the kind of the resin, it is cured even if it is irradiated with ultraviolet rays without blending them. There are cases. Various photocuring agents such as acetophenones, benzophenones, Michler's ketone, benzyl, benzoin, benzoin ether, benzyl ketals, thioxanthones are used as photoinitiators, and amines and diethylaminoethyl methacrylate are used as sensitizers. Various sensitizers are used.

The resin composition usually does not contain a solvent, but a small amount of solvent may be used in combination if necessary.

The thickness of the active energy ray-curable resin-cured layer (2) can be set appropriately, but it is from 1 to 20 μm, especially from 2-1.
It is often 0 μm.

The optical laminated sheet of the present invention is preferably produced by the following first method. That is, an optical isotropic sheet with or without an anchor coating layer (1)
The resin solution (2a) of the active energy ray-curable resin composition is supplied to the gap between the smoothing template material (3) and the smoothing template material (3) so that the resin solution (2a) is sandwiched between the two layers. To The optically isotropic sheet (1) is preliminarily supplied to the film-forming roll (4a), and the smoothing template material (3) is preliminarily supplied to the film-forming roll (4b), and both film-forming rolls (4a), The gap between (4b) is adjusted to a predetermined value. The film forming rolls (4a) and (4b) are configured so that they can be kept warm as necessary.

Then, the sandwiching layer (2b) is cured by irradiation with active energy rays to form an active energy ray-curable resin cured layer (2). Examples of active energy rays include ultraviolet rays and electron rays. The cumulative amount of light and dose during irradiation with active energy rays are set within the optimum range in consideration of the thickness of the active energy ray-curable resin cured layer (2), etc., and the smooth release property and activity of the smoothed template material (3) are set. The energy ray curable resin cured layer (2) should have solvent resistance.

As a result, a laminate comprising the optically isotropic sheet (1) / active energy ray-curable resin-cured layer (2) / smoothing template material (3) can be obtained. The smoothing template material (3) is peeled and removed from the layered product to obtain a layered sheet composed of the optically isotropic sheet (1) / active energy ray curable resin cured layer (2).

As the smoothing template material (3) above,
Biaxially oriented polyester films such as biaxially oriented polyethylene terephthalate sheet, biaxially oriented polybutylene terephthalate sheet, biaxially oriented polyethylene naphthalate sheet, and biaxially oriented polypropylene film are used. Stretched polyethylene terephthalate film is of particular importance. In this case, if the surface is subjected to corona discharge or flame treatment, it will be difficult to peel off the smoothing template material (3) in the subsequent steps, so be careful to use one that is not subjected to such treatment. .

The surface roughness of these smooth films is
0.15 μm or less, preferably 0.05 μm or less, further 0.01
When the surface roughness is required to be not more than 0.1 μm and the surface roughness exceeds 0.15 μm, an optical laminated sheet having desired smoothness cannot be obtained. Among the above-mentioned biaxially stretched polyethylene terephthalate films, which do not contain a filler, the surface smoothness is remarkably improved by the biaxial stretching, so that the smoothness can be maximized.

Second Method for Producing Laminated Optical Sheet of the Present Invention
The method is that the resin liquid (2a) of the active energy ray-curable resin composition is applied to one of the light isotropic sheet (1) with or without an anchor coating layer (1) or the smoothing template material (3) made of a smooth film. While casting, while controlling the thickness of the sandwiching layer (2b) by the roll gap while covering the casting layer with the smoothing template material (3) or the optically isotropic sheet (1), the active energy This is a method in which the sandwiching layer (2b) is cured by irradiation with rays to form an active energy ray-curable resin cured layer (2).

Third Process for Producing Laminated Optical Sheet of the Present Invention
In the method, the resin liquid (2a) of the active energy ray-curable resin composition is cast on the optically isotropic sheet (1) with or without the anchor coating layer, and the casting layer is smoothed. While controlling the thickness of the sandwiching layer (2b) while pressing the smoothed glass as the mold material (3), the sandwiching layer (2b) is cured by irradiation with active energy rays to cure the active energy ray curable resin. This is a method of forming a layer (2). In this method, the glass used is used repeatedly.

The surface roughness of the free surface of the active energy ray-curable resin cured layer (2) of the laminated sheet obtained by each of the above methods depends on the degree of surface smoothness of the smoothing template material (3). , 0.5 μm or less, preferably 0.2 μm or less, more preferably 0.1 μm or less. Generally, the surface roughness of a melt extruded film is 3 to 4 μm for a film having a thickness of 100 μm.
m, the surface roughness of the cast film is 100 to 100 μm, and the surface roughness of the free surface of the active energy ray-curable resin cured layer (2) is so small that it cannot be considered common sense. Is.

Further, the active energy ray-curable resin cured layer (2) of the laminated sheet also has excellent heat resistance, solvent resistance and transparent electrode forming property.

The laminated sheet of the present invention has an overall retardation value of 6 in consideration of its use in optical applications.
0 nm or less, preferably 30 nm or less, visible light transmittance is 6
It is desired to be 0% or more, preferably 70% or more.

A transparent electrode is provided on the active energy ray-curable resin cured layer (2) of the laminated sheet having the layer structure of the optically isotropic sheet (1) / active energy ray curable resin cured layer (2) obtained above. A liquid crystal cell substrate can be manufactured by providing the above structure and further forming an alignment film on it.

For forming the transparent electrode, a vacuum deposition method, a sputtering method, an ion plating method, a metal spraying method, a metal plating method, a chemical vapor deposition method, a spray method or the like is adopted.
The sputtering method is particularly important. As the material of the transparent electrode, a metal such as Sn, In, Ti, Pb, Tb or an oxide thereof is mainly used, and the layer thickness of the transparent electrode is at least 100 angstrom, and further 20
It is usually 0 angstrom or more.

The optical laminated sheet obtained by the method of the present invention is particularly important as an electrode substrate for manufacturing a liquid crystal display panel, but is used for applications such as retardation plate members, polarizing plate members, optical disks and optical cards. Can also be applied.

[0046]

In the optical laminated sheet of the present invention, the surface smoothness of the free surface of the active energy ray curable resin cured layer (2) located on the surface of the laminated sheet is extremely high. Even when it is used as an electrode substrate of a liquid crystal cell for encapsulating, it does not occur that the screen is very difficult to see due to colors such as purple and green.

[0047]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, “parts” means parts by weight.

Example 1 FIG. 1 is a process chart showing an example of a process for manufacturing an optical laminated sheet of the present invention.

In FIG. 1, (5) is a tank, (6) is a jacket, (7) is a lip-shaped discharge port, and (4a) and (4b) are a pair of film-forming rolls. (8) is an ultraviolet irradiation device. (9) is a nip roll, and (10) is a peeling roll for peeling the laminated sheet (S).

As an example of the base material layer, a water-soluble quaternized ester urethane-based anchor coating agent is applied to one side of a polycarbonate sheet (thickness 110 μm, retardation value 12 nm) and dried to form a 0.5 μm-thick anchor coating layer. After the provision, 20 parts of an ethylene-vinyl alcohol copolymer having an ethylene content of 32 mol%, 45 parts of water, and 5 parts of n-propanol are placed on the anchor coating layer.
A resin solution having a composition of 0 part and 4 parts of methylolated melamine (Sumitec M-3 manufactured by Sumitomo Chemical Co., Ltd.) was cast and passed through a drier at a temperature of 110 ° C. to be dried.
As a result, an air-permeable resin layer having a thickness of 8 μm was formed.

Similarly, an anchor coating layer having a thickness of 0.5 μm is provided on the other surface of the polycarbonate sheet which is the base layer, and the air-permeable resin layer having the same thickness as the above is provided on the anchor coating layer. Was set up.

Then, from above the air-permeable resin layer on one side,
Phenoxyether resin (manufactured by Tohto Kasei Co., Ltd.) 40
Part, 40 parts of methyl ethyl ketone, 20 parts of cellosolve acetate, 40 parts of 75% solution of an adduct of tolylene diisocyanate and trimethylolpropane (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) 40 parts using a curable resin composition using an applicator. And apply it at 80 ℃
Dry for 4 minutes, then heat at 130 ° C for 20 minutes,
A phenoxy ether resin-based thermally crosslinkable resin layer having a thickness of 10 μm was formed.

Similarly, a heat-crosslinkable resin layer having a thickness of 10 μm was formed on the other air-permeable resin layer.

As a result, the optical isotropy having the layer structure of heat-crosslinkable resin layer / air-permeable resin layer / anchor coating layer / base material layer / anchor coating layer / air-permeable resin layer / heat-crosslinkable resin layer is obtained. Sheet (1) was obtained.

Separately, as a smoothing template material (3), a thickness of 50
A biaxially stretched polyethylene terephthalate film (O type, manufactured by Teijin Limited) having a thickness of μm and a surface roughness of 0.004 μm and not subjected to corona discharge treatment was prepared.

1 part of benzophenone was added to 100 parts of epoxy acrylic resin "V-254PA" manufactured by Nippon Steel Chemical Co., Ltd. to prepare a resin liquid (2) of an active energy ray curable resin composition.
a) was prepared.

The resin liquid (2a) was charged into the tank (5), and a heating medium was sent to the jacket (6) to keep the contents at about 30 ° C. and degassed.

Then, pressure is applied to the upper space of the tank (5),
From the discharge port (7) into the gap between the film forming rolls (4a) and (4b), the resin liquid
(2a) was discharged.

To the film-forming rolls (4a) and (4b), the above-mentioned optically isotropic sheet (1) and smoothing template material (3) are respectively supplied in advance, and from the discharge port (7). Discharged resin liquid (2a)
Was sandwiched between the heat-crosslinkable resin layer surface of the optically isotropic sheet (1) and the smooth surface of the smoothing template material (3) to form a sandwich layer (2b).

The sandwiching sheet after passing through the film forming rolls (4a) and (4b) was irradiated with ultraviolet rays by the ultraviolet irradiation device (8) under the following conditions, and then the smoothing template material (3) was peeled off. The sandwiching layer (2b) was cured by irradiation with ultraviolet rays to become an active energy ray-curable resin cured layer (2). As a result, a laminated sheet (S) having a layer structure of active energy ray-curable resin cured layer (2) / optical isotropic sheet (1) was obtained. Smoothing mold material (3)
The peeling removal may be performed once after being once wound on a winder, not immediately after the irradiation with ultraviolet rays.

Ultraviolet irradiation conditions Ultraviolet irradiation device UVC-253 manufactured by USHIO INC.
/ 1M lamp High pressure mercury lamp 80W / cm or 1
20W / cm Irradiation distance 200mm Conveyor speed 5m / min or 3m / min

The conditions and results are shown in Table 1. The meanings of the evaluation items are as follows.・ Thickness (2) The thickness is the energy ray curable resin cured layer (2)
Thickness. -Peelability Smoothness of peeling of the biaxially stretched polyethylene terephthalate film as the smoothing mold material (3). (○: good, ×: bad) ・ Roughness The surface smoothness of the free surface of the active energy ray-curable resin cured layer (2) was measured by a non-contact surface roughness meter using light interference. -R value The retardation value of the entire laminated sheet (S). -Transmittance The visible light transmittance of the entire laminated sheet (S). -Hardness Pencil hardness-Solvent resistance The laminated sheet (S) is immersed in dimethylacetamide at 44 ± 1 ° C for 5 minutes to obtain an active energy ray-curable resin cured layer.
Whether or not (2) was dissolved was observed. (○: No abnormality, ×: Melting)

Table 1 Cumulative light intensity (2) Thick peeling Roughness R value Transmittance Hardness Solvent resistance No. (mJ / cm ² ) (μm) (μm) (nm) (%) Properties 1 354 3.6 ○ <0.1 16 90 4H ○ 2 354 4.5 ○ <0.1 16 89 4H ○ 3 538 6.8 ○ <0.1 17 89 5H ○ 4 675 7.7 ○ <0.1 17 88 5H ○

Next, an ITO layer having a thickness of 500 Å was formed on the surface of the cured layer (2) of the active energy ray-curable resin of the laminated sheets (S) of No. 1 to No. 4 obtained above by the sputtering method. The transparent electrode was directly formed. Using this sheet as an electrode substrate, a liquid crystal display panel was produced by a conventional method, including forming an alignment film, rubbing, assembling a liquid crystal cell, and laminating a retardation plate and a polarizing plate. The obtained liquid crystal display panel showed no coloring in the display and had a performance comparable to that of a liquid crystal display panel using glass as a substrate.

Example 2 As a base material layer, instead of a polycarbonate sheet, a polyarylate sheet (Kanefuchi Chemical Co., Ltd., thickness 100 μm) was used.
And a retardation value of 15 nm) were used to obtain an optically isotropic sheet (1) in the same manner as in Example 1.

1 part of benzophenone was added to 100 parts of phosphazene curable resin "Idemitsu PPZ" manufactured by Idemitsu Petrochemical Co., Ltd.
Resin solution of the active energy ray-curable resin composition
(2a) was prepared.

The optically isotropic sheet (1) and the resin liquid (2
Example 1 was repeated except that a) was used. The conditions and results are shown in Table 2.

Table 2 Cumulative light intensity (2) Thick peeling Roughness R value Transmittance Hardness Solvent resistance No. (mJ / cm ² ) (μm) (μm) (nm) (%) Properties 5 354 4.0 ○ <0.1 18 89 7H ○ 6 538 6.8 ○ <0.1 18 89 7H ○

Example 3 In No. 1 to No. 4 of Example 1, the heat-crosslinkable resin layer /
One heat-crosslinkable resin layer of the optically isotropic sheet (1) having a layer structure of air-permeable resin layer / anchor coating layer / base material layer / anchor coating layer / air-permeable resin layer / heat-crosslinkable resin layer Example 1 except that an anchor coating layer having a thickness of 1 μm was formed from a commercially available solvent-type urethane-based anchor coating agent and the resin liquid (2a) was brought into contact with the surface on the anchor coating layer side. When the above procedure was repeated, almost the same results as in Example 1 were obtained.

Example 4 20 parts of ethylene-vinyl alcohol copolymer having an ethylene content of 32 mol% and 45 parts of water were placed on a polyester film.
Parts, n-propanol 50 parts, methylolated melamine
(Sumitec M-3, manufactured by Sumitomo Chemical Co., Ltd.) A resin liquid having a composition of 4 parts is cast, passed through a drier at a temperature of 110 ° C. and dried to form a gas-permeable resin layer having a thickness of 15 μm. Let Subsequently, the same thermosetting resin composition as in Example 1 was applied thereto, dried and then heated to a thickness of 10 μm.
A heat-crosslinkable resin layer was formed.

The urethane-based adhesive solution was applied onto the air-permeable resin layer of the obtained laminated film and then dried, and the air-permeable resin layer side surface of the same laminated film as described above was overlaid thereon. The pieces were bonded together, heat-treated, and left to stand overnight, and then the polyester films on both sides were peeled off. Thereby, the thermally crosslinkable resin layer / air-permeable resin layer / adhesive layer /
An optically isotropic sheet (1) having a layer structure composed of a gas-proof resin layer / a heat-crosslinkable resin layer was obtained.

Using this optically isotropic sheet (1), Example 1
A 4.0 μm-thick active energy ray-curable resin cured layer (2) is formed on one side in the same manner as above, and then a 4.0 μm-thick active energy ray-curable resin cured layer (2) is also formed on the other side. Was formed. The surface roughness of the active energy ray-curable resin cured layer (2) side of the obtained laminated sheet (S) was 0.1 μm or less on both sides.

Example 5 The resin solution (2a) of Example 1 was cast on the surface of the thermally crosslinkable resin layer of the optically isotropic sheet (1) of Example 1, and the smoothing template material was cast on the casting layer. UV irradiation was performed while pressing the glass having a smoothed surface roughness of 0.05 μm as (3) while controlling the thickness of the sandwiching layer (2b) to 5.0 μm, and then the glass was peeled and removed. The surface roughness of the active energy ray-curable resin cured layer (2) surface of the obtained laminated sheet (S) was 0.1 μm or less.

[0074]

In the optical laminated sheet of the present invention,
For example, even when this is used as an electrode substrate of a liquid crystal cell in which STN liquid crystal is sealed, there is no possibility that the screen is very difficult to see due to colors such as purple and green on the display.

As the liquid crystal display panel becomes larger year by year,
Although the spread of the STN liquid crystal system is remarkable, the present invention allows the display characteristics to be comparable even if a plastics substrate is used instead of the glass substrate for the purpose.

Despite such excellent performance, it has an industrial advantage that its manufacturing process is simple.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a manufacturing process of an optical laminated sheet of the present invention.

[Explanation of symbols]

 (1) ... Optical isotropic sheet, (2) ... Active energy ray curable resin cured layer, (2a) ... Resin liquid, (2b) ... Holding layer, (3) ... Smoothing template material, (4a), (4b) ... Film forming roll, (5) ... Tank, (6) ... Jacket, (7) ... Discharge port, (8) ... UV irradiation device, (9) ... Nip roll, (10) ... Peeling roll, (S) ... laminated sheet

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[Procedure amendment]

[Submission date] December 2, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

[0048] Example 1 1 Ri process diagram der showing an example of a manufacturing process of the optical laminated sheet of the present invention, enlarged cross-section of the X portion in FIG. 2 in FIG. 1
FIG, 3 is Ru enlarged sectional view der the Y portion in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a manufacturing process of an optical laminated sheet of the present invention.

FIG. 2 is an enlarged cross-sectional view of a portion X in FIG.

FIG. 3 is an enlarged cross-sectional view of a Y portion in FIG.

[Explanation of symbols] (1) ... Optical isotropic sheet, (2) ... Active energy ray-curable resin cured layer, (2a) ... Resin liquid, (2b) ... Holding layer, (3) ... Smoothing template material , (4a), (4b) ... Film forming roll, (5) ... Tank, (6) ... Jacket, (7) ... Discharge port, (8) ... UV irradiation device, (9) ... Nip roll, (10) … Peeling roll, (S)… laminated sheet

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

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Claims (2)

[Claims] 1. An active energy ray-curable resin cured layer (2) directly or through an anchor coating layer on a single-layer or multi-layered optically isotropic sheet (1) in which at least a surface layer is a thermally crosslinkable resin layer. ) Is provided, the surface roughness of the free surface of the active energy ray-curable resin cured layer (2) is 0.5 μm or less, the retardation value of the entire laminated sheet is 60 nm or less, and the visible light transmission is An optical laminated sheet having a rate of 60% or more. 2. A single-layer or multi-layer sheet having at least a surface layer of a heat-crosslinkable resin layer, and an optically isotropic sheet (1) with or without an anchor coating layer and a smoothing template having a smooth surface. The resin liquid (2a) of the active energy ray-curable resin composition is supplied to the gap between the material (3) and the resin liquid (2a) so as to be sandwiched between them, and then the active energy ray is irradiated. A method for producing an optical laminated sheet, characterized in that the sandwiching layer (2b) is cured by the above to form an active energy ray-curable resin cured layer (2).