JPH09294959A - Production of laminated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to continuously produce a 100nm thick layer with controlled thickness distribution within 45% or lower and having no defect such as a vertical wrinkling, turning backside, etc., on a thin flexible film substrate. SOLUTION: This method is to form layers on at least one side of a flexible substrate and produce a laminated body. At least one layer of the layers is formed by applying a coating liquid containing one or more metal alkoxides or one or more ultraviolet curable resins as main components and having 0.1-10wt.% of solid matter concentration and 0.1-200cP viscosity at the time of application by microgravure application method and drying and curing the coating liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminate, and more particularly to a method for producing a laminate useful as an optical material, and more particularly to an antireflection-coated plastic film and an antireflection-coated liquid crystal display device. TECHNICAL FIELD The present invention relates to a method useful for producing a polarizing plate for use.

[0002]

2. Description of the Related Art It is known from an optical theory that a layer of which the refractive index and the optical film thickness are controlled is laminated on a substrate such as glass or plastic to give the substrate various optical functions. Among them, the antireflection coating utilizing the interference of the reflected light of the base material and the reflected light from the laminated thin film has been actively studied in recent years in order to improve the visibility of the spectacle lens, the liquid crystal display element and the like. . Especially in the case of liquid crystal display devices used in video cameras, personal computers, car navigation systems, etc., when used outdoors, the visibility is extremely deteriorated due to the reflection of external light reflection. It is considered essential. Conventional techniques of such an antireflection coating are roughly classified into a vapor phase method and a wet method. Each of the above will be described below.

The vapor phase method includes a vacuum vapor deposition method, a sputtering method, an ion plating method, etc., which can form a layer having a highly controlled refractive index and optical film thickness, and has little variation in the in-plane antireflection effect. A laminated body can be obtained. However, the vapor phase method has a problem that the production rate is slow and the cost is high.

Wet method: There are a dipping method of immersing the base material in a coating liquid, a spin coating method of rotating the base material at a high speed, and the like, both of which can form a layer having a highly controlled refractive index and film thickness. is there. However, in the case of the dipping method, when a film used for a polarizing plate requires a single-sided antireflection coating, masking is required on the non-film-forming surface, which causes a problem that the number of steps is increased. Further, in the case of the spin coating method, in addition to the batch type film forming process, since the base material is rotated at a high speed for coating, a considerable amount of coating liquid is scattered,
There is a problem that productivity is low.

As a method for solving these problems, a metal alkoxide-based coating material is continuously coated on a glass substrate by a reverse roll coating method, and then a layer of about 1 μm or less is ± 10 by heat drying at several hundred degrees. A method of forming a film with a film thickness distribution of not more than 10% is disclosed (Japanese Patent Laid-Open No. 7-68219).
Issue). However, in this method, when coating a flexible base material such as a thin plastic film, a back bead phenomenon occurs in which the coating liquid spins on the back side of the base material, and in order to prevent back beading, Even if the roll width is narrowed, there is a problem that vertical wrinkles occur in the film substrate portion in contact with the roll end. Further, in the case of a plastic film having low heat resistance, the coating layer cannot be completely dried by heat, so that the coating layer becomes thermodynamically unstable. It is difficult to control the thickness distribution within ± 5%.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and its object is to provide a flexible thin film base material with vertical wrinkles and linings. An object of the present invention is to provide a manufacturing method for continuously forming a layer having a thickness of about 100 nm in which the layer thickness distribution is controlled to ± 5% or less without defects such as the above.

[0007]

A method for producing a laminated body according to claim 1 (hereinafter, the invention according to claim 1 is referred to as the present invention 1) comprises forming a layer on at least one surface of a flexible base material. In the method for producing a laminate, at least one of the layers is mainly composed of one or more kinds of metal alkoxide or one or more kinds of ultraviolet curable resin, and has a viscosity of 0.1 to 20 at the time of coating.
It is characterized by being formed by applying a coating liquid of 0 cP and a solid content concentration of 0.1 to 10% by weight by a microgravure coating method, followed by drying and curing.

The flexible substrate used in the present invention 1 is not particularly limited as long as it is a flexible substrate, and examples thereof include a plastic film, and examples of the plastic material include: , A polycarbonate film, a polyethylene terephthalate film, a cellulose triacetate film and the like.

The micro gravure coating method used in the present invention 1 is a gravure roll having a diameter of about 20 to 50 mm and engraved with a gravure pattern on the entire circumference thereof, which is provided under a flexible base material and a base material. Arranged so that the conveying direction of the material and the axial direction of the gravure roll are orthogonal to each other, while rotating the gravure roll in the reverse direction with respect to the conveying direction of the base material, the excess coating liquid is applied from the surface of this gravure roll by a doctor blade. Before applying, a certain amount of the coating liquid is applied to the lower surface of the base material at a position where the upper surface of the base material is in a free state, and the base material is solidly coated with the coating liquid. It is a gravure coating method.

An example of the micro gravure coating method will be described with reference to FIG. 1 showing the gravure head portion. The coating liquid 5 is supplied from the coating liquid supply unit 1 to the coating liquid reservoir 3, and a part of the micro gravure roll 2 having a gravure pattern engraved on the entire circumference is put into the coating liquid reservoir 3 to apply the coating liquid 5 to the microgravure. The micro gravure roll 2 is made to adhere to the roll 2, the surplus coating liquid 5 is scraped off from the surface of the micro gravure roll 2 by the doctor blade 4, and then the base 6 moving at a predetermined transport speed is applied with a solid coating.

In the present invention 1, as a coating liquid, a liquid containing at least one metal alkoxide or at least one ultraviolet curable resin as a main component is used.

The above metal alkoxide is preferably used as a raw material of a coating liquid which can easily obtain an inorganic layer at a lower temperature than before, and by combining a plurality of metal alkoxides, a thin film having arbitrary optical characteristics can be obtained. Can be formed. As the metal alkoxide used in the present invention 1, for example, silicon alkoxide, titanium alkoxide, zirconium alkoxide, aluminum alkoxide, antimony alkoxide, lanthanum alkoxide, tin alkoxide, tantalum alkoxide, yttrium alkoxide, etc. are relatively easily available. It is suitable. As the metal alkoxide, not only an alkoxide in which only the alkoxy groups such as a methoxy group, an ethoxy group and an isopropoxy group are bonded to all the bonds of the metal atom, but a part thereof is an alkyl group such as a methyl group or an ethyl group. It may be an alkoxide substituted with a group or another group.

The metal alkoxides preferably used in the present invention 1 are listed below. Silicon alkoxide tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, phenyltriethoxysilane, γ-glycidoxypropyldimethoxymethylsilane, [N- (β- Aminoethyl)
-Γ-aminopropyl] dimethoxymethylsilane

Titanium alkoxide Titanium tetraethoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide zirconium alkoxide Zirconium tetraethoxide, zirconium tetraisopropoxide, zirconium tetra-n-butoxide aluminum alkoxide aluminum trimethoxide, aluminum trioxide. Ethoxide, aluminum triisopropoxide, aluminum tri-n-butoxide

Antimony alkoxide Antimony triethoxide, antimony tri-n-butoxide lanthanum alkoxide, lanthanum triethoxide, lanthanum triisopropoxide tin alkoxide tin tetraethoxide, tin tetraisopropoxide, tin tetra-n-butoxide.

Tantalum alkoxide Tantalum pentamethoxide, tantalum pentaethoxide, tantalum pentaisopropoxide yttrium alkoxide Yttrium trimethoxide, yttrium triethoxide, yttrium triisopropoxide

The metal alkoxide is usually applied on a substrate as a metal alkoxide paint in which an alkoxy group is hydrolyzed in an organic solvent, and is formed as a metal oxide by polycondensation of hydroxyl groups when the organic solvent volatilizes. To be done. Therefore, the coating liquid containing at least one kind of metal alkoxide as the main component used in the present invention 1 does not mean that the main component is only the metal alkoxide, but the metal alkoxide is partially hydrolyzed and further partially polycondensed. May be included as an oligomer. Also, colloid particles that have been previously hydrolyzed and polycondensed may be dispersed in a solvent. As the colloid, colloidal silica and colloidal titanium are available at a relatively low cost and are preferably used.
Alternatively, oxide fine particles prepared using the metal alkoxide may be dispersed in an organic solvent. Examples of the oxide particles include SiO ₂ particles, TiO ₂ particles, ZrO ₂ particles, Al ₂ O ₃ particles, Sb ₂ O ₅ particles, La ₂ O ₃ particles, SnO ₂ particles, Ta ₂ O ₅ particles.
Examples include fine particles and Y ₂ O ₃ fine particles. Further, a metal alkoxide-based coating liquid chelated with β-diketones, ethyl acetoacetates or the like may be used for the purpose of controlling the hydrolysis rate and improving the chemical stability of the coating liquid.

As the ultraviolet curable resin, an ultraviolet curable resin which is usually used for forming an organic thin film, particularly an optical thin film, is used as it is. For example, a (meth) acrylate functional group, that is, a polyester resin, a polyether resin, an acrylic resin, a urethane resin, an epoxy resin into which a (meth) acryloyl group or the like is introduced can be used. These resins are usually used together with a radical polymerization initiator.

It is also possible to use an ultraviolet-curable resin silicone acrylate in which a (meth) acryloyl group or the like is introduced on the surface of silica fine particles.

Further, examples of the ultraviolet curable resin include epoxy resin and vinyl ether resin used together with a photoreactive cationic polymerization initiator.

The above-mentioned UV-curable resin may contain a UV-reactive monomer and is usually mixed with the above-mentioned polymerization initiator to form a coating liquid. Further, an organic solvent or the like for adjusting the viscosity and solid content concentration of the coating liquid is mixed and used in the coating liquid. Therefore, the coating liquid containing at least one kind of ultraviolet curable resin as a main component in the present invention 1 may be, for example, a mixture of an ultraviolet curable resin, a monomer, a polymerization initiator, an organic solvent and the like.

Further, in order to control the refractive index of a thin film obtained from a coating liquid containing at least one kind of the above ultraviolet curable resin as a main component, fine particles having an arbitrary refractive index are added. To increase the refractive index, for example, ZrO ₂
(Refractive index 2.1), TiO ₂ (refractive index around 2.3), A
l ₂ O ₃ (refractive index 1.63) and the like.

Examples of the above organic solvent include hydrocarbon solvents, alcohol solvents, ether solvents, ester solvents and the like. Among them, hexane, cyclohexane, toluene, ethanol, isopropyl alcohol, methyl ethyl ketone, ethyl acetate and the like are preferably used.

The viscosity of the coating liquid containing at least one metal alkoxide or at least one ultraviolet-curable resin used in the present invention at the time of coating becomes lower when a gravure roll having a smaller number of lines is used. Even if an attempt is made to transfer a large amount of coating liquid, it becomes difficult to obtain a desired layer thickness, and when the coating thickness is increased, fine bubbles are apt to be mixed in when the film is transferred from the gravure roll to the substrate, and the appearance of the coating film is deteriorated. After transfer, when the solvent in the coating liquid volatilizes, the smoothness of the layer surface decreases and the layer thickness distribution increases, so it is limited to 0.1 to 200 cP. The viscosity is the viscosity measured by an E-type viscometer.

Further, when the solid content concentration of the above-mentioned coating liquid is low, it is difficult to obtain a desired layer thickness even if a large amount of the coating liquid is transferred than the gravure roll, and it becomes difficult to obtain a desired layer thickness. Not only becomes large, but also the stability of the coating liquid becomes poor, so it is limited to 0.1 to 10% by weight, preferably 1 to 5% by weight.

In the case of a coating liquid containing a metal alkoxide as a main component, the above-mentioned solid content concentration means that the solvent or the like contained in the coating liquid is volatilized to form a metal alkoxide, a partial hydrolyzate of a metal alkoxide, an oligomer or the like. Is a weight percentage with respect to the total coating liquid of the metal oxide obtained by complete polycondensation,
In the case of a coating liquid containing an ultraviolet curable resin as a main component, it is the weight percentage of the polymer obtained after the polymerization reaction of the ultraviolet curable resin and the reactive monomer is completed by the coating and ultraviolet irradiation steps, relative to the coating liquid. .

The conditions of the above-mentioned drying and curing are not particularly limited in the case of a coating liquid containing a metal alkoxide as a main component, and they are not particularly limited, but are not less than the boiling point of the solvent,
It is preferably lower than the heat resistant temperature of the substrate. The time is not particularly limited, but if it is carried out for a long time, a more optically stable coating film can be obtained.

In the case of a coating liquid containing an ultraviolet curable resin as a main component, when the coating liquid contains a solvent, it is preferable to dry it at a temperature not lower than the boiling point of the solvent. The preferable irradiation wavelength of ultraviolet irradiation is determined by the initiator contained in the coating liquid. The amount of irradiation varies depending on the type of UV-curable resin, the type of initiator, the thickness of the coating film, etc., but the amount of irradiation capable of completing the polymerization reaction gives a coating film having excellent optical stability.

The method for producing a laminate according to claim 2 (hereinafter, the invention according to claim 2 is referred to as the present invention 2) is a gravure pattern engraved on a gravure roll under the microgravure coating method. Is 70 to 250 lines / inch, the depth of the gravure pattern engraved on the gravure roll is 13 to 150 μm, the rotation speed of the gravure roll is 5 to 200 rpm, and the transfer speed of the substrate is limited to 1 to 30 m / min. It is characterized by

The coating solution used in the present invention 2 has a viscosity at the time of coating of 0.1 to 200 cP and a solid content concentration of 0.1 to 1.
It is limited to 0% by weight (preferably 1 to 5% by weight). The reason for limiting the viscosity and the solid content concentration at the time of application is the present invention 1
Is the same as

In the present invention 2, as the coating conditions in the micro gravure coating method, as described above, the number of lines and depth of the gravure pattern engraved on the gravure roll, the number of rotations of the gravure roll, and the transfer of the substrate. Limited speed. Hereinafter, the reason for this limitation will be described in detail.

The amount of the coating liquid transferred to the substrate in the microgravure coating method is determined by the number of lines and the depth of the gravure pattern engraved on the gravure roll. Generally, as the number of lines decreases, the depth increases, a large amount of the coating liquid is transferred to the base material, and the thickness of the layer formed increases. Conversely, as the number of lines increases, the depth decreases, a small amount of coating liquid is transferred to the substrate, and the layer thickness also decreases. Therefore, when the number of lines in the present invention 2 becomes small, the amount of the coating liquid transferred increases,
Since the smoothness of the layer surface after transfer is lowered and the desired layer thickness distribution cannot be obtained, and when the layer thickness is increased, the amount of the coating liquid transferred is reduced and the desired layer thickness cannot be obtained. Therefore, it is limited to 70 to 250 lines / inch. , Preferably 90 to 200 lines / inch.

When the depth of the gravure pattern engraved on the gravure roll according to the second aspect of the present invention is small, the amount of the coating liquid transferred is small and the desired layer thickness cannot be obtained. After that, the smoothness of the layer surface decreases and the desired layer thickness distribution cannot be obtained.
It is limited to 13 to 150 μm, and preferably 30 to 10
0 μm.

When the rotation speed of the gravure roll is small, the amount of the coating liquid transferred is small and the desired layer thickness cannot be obtained, and when it is large, the coating liquid transferred is large and the layer surface after transfer is smooth. Since the property is deteriorated and the desired layer thickness distribution cannot be obtained, it is limited to 5 to 200 rpm, and preferably 30 to 180 rpm.

Further, if the base material is conveyed at a low speed, the speed tends to be uneven, and the layer thickness distribution tends to become large, and if it becomes faster, it is necessary to lengthen the drying device in the drying process which is a post-process. Limited to 1-30m / min,
It is preferably 2 to 10 m / min.

The method for producing a laminate according to claim 3 (hereinafter, the invention according to claim 3 is referred to as the present invention 3) is the same as the method for producing a laminate according to the present invention 1 or 2, wherein the metal alkoxide is Si or Ti. The method is the same as the method for producing a laminate according to the first or second aspect of the present invention, except that it is limited to alkoxide of Zr or Al. The reason for this is that the refractive index of the resulting thin film can be easily controlled, the stability of the coating liquid is excellent, and it can be obtained at low cost. Therefore, it is particularly suitable as a coating liquid material for obtaining an optical thin film. It depends.

Preferable examples of Si, Ti, Zr or Al alkoxide used in the present invention 3 are the same as those mentioned in the description of the present invention 1 for each metal alkoxide. Also, as a metal alkoxide,
Not only a simple metal alkoxide, but a part of the metal alkoxide partially hydrolyzed and further partially polycondensed to form an oligomer may be contained, and colloid particles preliminarily hydrolyzed and polycondensed may be contained. It may be one dispersed in a solvent, or one in which the oxide fine particles prepared by using the metal alkoxide are dispersed in an organic solvent, the hydrolysis rate is controlled, and the chemistry of the coating liquid is controlled. Similar to the first aspect of the present invention, an alkoxide-based coating liquid chelated with β-diketones, ethyl acetoacetates or the like may be used for the purpose of improving the thermal stability.

The method for producing a laminate according to claim 4 (hereinafter, the invention according to claim 4 is referred to as the present invention 4) is the same as the method for producing a laminate according to the present invention 1 or 2, wherein the ultraviolet curable resin is ( The method is the same as the method for producing a laminate of the first or second aspect of the present invention, except that it is limited to those having a (meth) acrylate functional group. The reason for this is that the obtained thin film has excellent hardness, the stability of the coating liquid is excellent, it is available at low cost, and there are many types. As being particularly suitable as

Suitable examples of the UV-curable resin having a (meth) acrylate functional group used in the present invention 4 are the same as those mentioned in the description of the present invention 1. Further, as the ultraviolet curable resin, an oligomer, a monomer, a polymerization initiator, etc., an organic solvent for adjusting the viscosity of the coating liquid and the solid content concentration, if necessary, for controlling the refractive index of the resulting thin film The fine particles and the like are used in the same manner as in the first aspect of the present invention.

In the method for producing a laminate according to claim 5 (hereinafter, the invention according to claim 5 is referred to as the present invention 5), the flexible substrate has a light transmittance of 80 in the visible light wavelength range. % Or more of the plastic film. The method for producing a laminate according to claim 1, wherein

The flexible base material used in the present invention 5 is not particularly limited as long as it is a plastic film having a light transmittance of 80% or more in the visible light wavelength range, and the material of the film is, for example, Cellulose triacetate film,
Examples thereof include a polycarbonate film and a polyethylene terephthalate film. In particular, a cellulose triacetate film has a small optical anisotropy and a good visible light transmittance, and thus is suitable as a film used for a polarizing plate for a liquid crystal display device. The polycarbonate film is slightly inferior to the cellulose triacetate film in visible light transmittance, but is preferable because it is excellent in heat resistance. Further, the plastic film may be surface-treated in order to improve the coatability. Examples of the surface treatment include corona discharge treatment and saponification treatment.

According to the fifth aspect of the present invention, since a plastic film having a high transmittance in the visible light wavelength region is used, a laminate particularly suitable for optical member applications can be obtained.

The method for producing a laminate according to claim 6 (hereinafter, the invention according to claim 6 is referred to as the present invention 6) comprises:
A hard coating layer is directly provided, and (2) the coating liquid according to claim 1, 3 or 4, which can form a layer having a higher refractive index than the plastic film and the hard coating layer on the hard coating layer. Item 3 is applied under the microgravure coating conditions, dried and cured to provide a high refractive index layer, and (3) then, a refractive index lower than the high refractive index layer is provided on the high refractive index layer. The coating liquid according to claim 1, 3 or 4 capable of forming a layer having a low refractive index layer is formed by applying the coating liquid according to the microgravure coating conditions according to claim 2 and drying and curing. ) Furthermore, an antifouling layer having a layer thickness of 1 to 20 nm is provided on the low refractive index layer.

A sixth object of the present invention is to form an antireflection treatment layer having excellent abrasion resistance and antifouling property on the flexible plastic film according to the fifth invention.

Hereinafter, the present invention 6 will be described along with the steps.
First, a hard coat layer is laminated on at least one surface of the plastic film of claim 5 so as to be in contact with the film. This hard coat layer is provided for the purpose of improving the abrasion resistance of the laminate. The hard coat layer is not particularly limited, but it is preferable to use a commercially available hard coat agent such as an ultraviolet curable type or an electron beam curable type having excellent visible light transmittance because a laminate suitable for optical use can be obtained. Further, it is preferable that the hard coat layer has a refractive index within ± 0.5% of the refractive index of the substrate for the purpose of eliminating an optical interface with the substrate. The thickness of the hard coat layer is not particularly limited, but is preferably 0.5 μm or more, and more preferably 2.0 μm or more in order to impart sufficient abrasion resistance to the laminate.

Next, the coating solution according to claim 1, 3 or 4 capable of forming a layer having a higher refractive index than the plastic film and the hard coat layer is applied under the microgravure coating conditions according to claim 2. Work, dry, cure,
Provide a high refractive index layer. The refractive index of the high refractive index layer must be higher than that of the substrate and the hard coat layer in order to exert the antireflection effect. As the coating liquid material for forming the high refractive index layer, the viscosity at the time of coating is 0.1 to 200 cP,
It is not particularly limited as long as it is a coating liquid having a solid content concentration of 0.1 to 10% by weight and can form a layer having a higher refractive index than the plastic film and the hard coat layer. For example, in the case of a coating liquid containing titanium alkoxide as a main component, a layer having a refractive index of about 2.0 can be obtained. Further, also in the case of a coating liquid containing zirconia alkoxide as a main component, a layer having a refractive index of about 2.0 can be obtained.

Next, the coating liquid according to claim 1, 3 or 4, which can form a layer having a refractive index lower than that of the high refractive index layer, on the high refractive index layer. A low refractive index layer is provided by coating, drying and curing under microgravure coating conditions. The low refractive index layer should have a lower refractive index than the high refractive index layer in order to exert an antireflection effect. As the coating liquid material for forming the low refractive index layer, the viscosity during coating is 0.1 to 200 cP, and the solid content concentration is 0.1 to 1
The coating liquid is 0% by weight and is not particularly limited as long as it can form a layer having a lower refractive index than the high refractive index layer. For example, in the case of a coating liquid containing silicon alkoxide as a main component, a layer having a refractive index of about 1.4 can be obtained. Further, in the case of a coating liquid containing an ultraviolet curable resin having a (meth) acrylate functional group as a main component, a layer having a refractive index of about 1.5 can be obtained.

The thicknesses of the high refractive index layer and the low refractive index layer are not particularly limited, but a layered product exhibiting an excellent antireflection effect can be obtained by film formation under the following conditions in terms of optical theory. High refractive index layer 1.4 <n ₁ <2.1 (mλ / 4) × 0.7 <n ₁ d ₁ <(mλ / 4) × 1.
3 Low refractive index layer 1.2 <n ₂ <1.5 (nλ / 4) × 0.7 <n ₂ d ₂ <(nλ / 4) × 1.
3 n ₁ : refractive index of high refractive index layer d ₁ : layer thickness of high refractive index layer n ₂ : refractive index of low refractive index layer d ₂ : layer thickness of low refractive index layer m: positive integer n: positive Odd integer λ: Calculation center wavelength

Next, an antifouling layer is provided on the low refractive index layer. The type of the antifouling layer is not limited, but a contact angle with water of 100 degrees or more is preferable as a measure of the antifouling function. Examples of the coating agent for forming the antifouling layer include fluorine-containing compounds. Among the fluorine-containing compounds, 2-perfluorooctylethyltriaminosilane, which is a fluorine-containing aminosilane compound, has low adhesion to the low-refractive index layer formed by a coating liquid containing silicon alkoxide as a main component. It is particularly preferable because it is excellent. The thickness of the antifouling layer becomes insufficient to obtain a sufficient antifouling effect, and the thicker the antifouling layer becomes, the poor abrasion resistance of the antifouling layer causes the appearance failure. Therefore, it is limited to 1 to 20 nm. The coating method used for forming the antifouling layer may be the above-mentioned microgravure coating method, but may be any other known coating method and is not particularly limited.

According to a seventh aspect of the present invention (hereinafter, the invention of the seventh aspect is referred to as the seventh aspect of the present invention) of the polarizing plate, the laminated body obtained by the production method of the sixth aspect has an intervening layer interposed therebetween. Alternatively, it is characterized in that the polarizing elements are laminated without any interposition.

The polarizing element is not particularly limited,
Examples thereof include a polyvinyl alcohol film, a polyvinyl formal film, and a polyvinyl acetal film, which are obtained by dyeing with iodine or a dye and stretching. Moreover, a cellulose triacetate film is mentioned as said intervening layer.

The method for producing a polarizing plate according to the present invention 7 provides the method according to claim 6.
A polarizing element is laminated on the base material layer (plastic film) of the laminate obtained by the production method described above via the above-mentioned intervening layer for production. Further, without using the above-mentioned intervening layer,
You may laminate | stack a polarizing element directly on the base material layer of the laminated body obtained by the manufacturing method of Claim 6. Further, a cellulose triacetate film may be further laminated on the polarizing element layer of the laminate thus obtained.

The polarizing plate of Invention 7 is preferably used as a member for a liquid crystal display device.

[0054]

Embodiments of the present invention will be described below.

(Example 1) Preparation of coating liquid: To 15 mol of isopropyl alcohol,
1 mol of tetraethoxysilane and 4 mol of water having a pH of 11.7 were added, and the mixture was stirred at 20 ° C. for 2 hours to obtain a liquid (A). To 15 mol of isopropyl alcohol, 1 mol of tetraethoxysilane and 6 mol of water having a pH of 1.2 were added, and the mixture was stirred at 20 ° C. for 2 hours to obtain a liquid (B). Furthermore, the weight ratio (A) / (B) =
Mix two solutions at 1.5 and stir for 2 hours at 20 ° C. (C)
A liquid was obtained. Isopropyl alcohol was further added to the obtained liquid (C) to obtain a solid content concentration of 4.0% by weight and a viscosity of 3.7c.
P [measured at 20 ° C. using an E-type viscometer (DVM-E manufactured by Tokyo Keiki Co., Ltd.). The viscosities of the following examples and comparative examples were measured in the same manner. ] To obtain a coating liquid.

Using the obtained coating liquid, a film was formed on a substrate by the microgravure coating method shown in FIG. 1 under the following coating conditions to obtain a laminate. Substrate type: Polycarbonate film (Teijin Panlite, Teijin Panlite, thickness 80 μm). Micro gravure roll: Number of lines is 180 lines / inch, depth is 20mm with gravure pattern of 40μm
Micro gravure roll. Microgravure roll rotation speed: 120 rpm Coating temperature: 20 ° C Substrate transport speed: 5 m / min Drying oven length: 5 m Drying temperature: 110 ° C

5 10 samples were sampled from the obtained laminated body, and a spectrophotometer (manufactured by Shimadzu Corporation, UV-3101P) was used.
The minimum reflectance wavelength (4nd) in the visible light region was determined using C) (n is the refractive index of the layer, and d is the layer thickness). Since the refractive index (n) of the obtained layer is considered to be almost constant, the layer thickness can be calculated from the minimum reflectance wavelength (4nd). The coating film of the obtained laminate had no visible defects such as coating unevenness, vertical wrinkles, and backing. Minimum reflectance wavelength (4nd)
The layer thickness calculated from was an average of 110 nm, and the layer thickness distribution was ± 4%.

Example 2 Isopropyl alcohol was added to the coating solution prepared in Example 1 to obtain a coating solution having a solid content concentration of 2.0% by weight and a viscosity of 2.7 cP. Using the obtained coating liquid, a film was formed on the substrate by the microgravure coating method shown in FIG. 1 under the following coating conditions to obtain a laminate. Substrate type: the same as in Example 1. Micro gravure roll: diameter of 20 mm with gravure pattern with 80 lines / inch and depth of 130 μm
Micro gravure roll. Micro gravure roll rotation speed: 100 rpm Coating temperature, substrate transfer speed, drying oven length and drying temperature are
Same as Example 1.

The obtained laminate was evaluated in the same manner as in Example 1. As a result, the coating film of the obtained laminate did not show coating defects such as coating unevenness, vertical wrinkles, and backing. The layer thickness was 125 nm on average, and the layer thickness distribution was ± 4%.

Example 3 Preparation of coating liquid: To 30 mol of isopropyl alcohol,
0.3 mol of tetraethoxysilane and 0.7 mol of water containing 0.036% by weight of hydrogen chloride were added, and the mixture was allowed to stand for 20 hours for 20 hours.
Stirred at ° C. Next, 0.7 mol of titanium-n-butoxide was added, and the mixture was further stirred for 2 hours. Isopropyl alcohol was further added to this solution to obtain a solid content concentration of 2.0.
A coating liquid having a weight% and a viscosity of 2.0 cP was obtained.

Using the obtained coating solution, a film was formed on a substrate by the microgravure coating method shown in FIG. 1 under the following coating conditions to obtain a laminate. Substrate type: Cellulose triacetate film (Fuji Tack, thickness 80 μm, manufactured by Fuji Photo Film Co., Ltd.). Micro gravure roll: 100 lines / inch, depth 20 mm with gravure pattern of 75 μm
Micro gravure roll. Micro gravure roll rotation speed: 40 rpm Coating temperature, substrate transfer speed, drying oven length and drying temperature are
Same as Example 1.

The obtained laminated body was evaluated in the same manner as in Example 1. As a result, the coating film of the obtained laminated body was free from defects such as coating unevenness, vertical wrinkles, and backing. The layer thickness was 120 nm on average, and the layer thickness distribution was ± 4%.

(Embodiment 4) Instead of the micro gravure roll in Embodiment 3, a diameter of 20 mm having a gravure pattern with a line number of 50 lines / inch and a depth of 200 μm.
A laminated body was obtained in the same manner as in Example 3 except that the microgravure roll of 1 was used.

The obtained laminate was evaluated in the same manner as in Example 1. As a result, the layer thickness of the coating film of the obtained laminate was 30 on average.
It was 0 nm, and the layer thickness distribution was ± 5%.

Example 5 A cellulose triacetate film having a hard coat layer of about 3 μm laminated was obtained using a commercially available acrylic hard coat agent. In order to perform antireflection coating on this film, a high refractive index layer, a low refractive index layer, and an antifouling layer were formed in this order as described below to obtain a laminate.

High Refractive Index Layer Using the same coating liquid as in Example 3, a film was formed on the hard coat layer under the following coating conditions by the microgravure coating method shown in FIG. Micro gravure roll: 100 lines / inch, depth 20 mm with gravure pattern of 75 μm
Micro gravure roll. Micro gravure roll rotation speed: 10 rpm Coating temperature: 20 ° C Substrate conveying speed: 3 m / min Drying oven length: 5 m Drying temperature: 120 ° C

Low Refractive Index Layer Preparation of Coating Liquid: 15 mol of isopropyl alcohol,
1 mol of tetraethoxysilane and 6 mol of water containing 0.36% by weight of hydrogen chloride were added, and the mixture was stirred at 20 ° C. for 2 hours. To this liquid, isopropyl alcohol was further added,
A coating liquid having a solid content concentration of 2.0% by weight and a viscosity of 2.0 cP was obtained. Using the obtained coating liquid, a film was formed on the high refractive index layer by the microgravure coating method shown in FIG. 1 under the following coating conditions. Micro gravure roll: Number of lines is 180 lines / inch, depth is 20mm with gravure pattern of 40μm
Micro gravure roll. Micro gravure roll rotation speed: 30 rpm Coating temperature: 20 ° C Substrate conveying speed: 5 m / min Drying oven length: 5 m Drying temperature: 110 ° C

Preparation of antifouling layer coating liquid: 2-perfluorooctylethyltriaminosilane was diluted with a commercially available fluorine-based solvent to a solid content concentration of 0.5% by weight. Using the obtained coating liquid, FIG.
A film was formed on the low refractive index layer according to the following coating conditions by the microgravure coating method shown in FIG. Micro gravure roll: Number of lines is 180 lines / inch, depth is 20mm with gravure pattern of 40μm
Micro gravure roll. Microgravure roll rotation speed: 80 rpm Coating temperature: 20 ° C. Substrate conveying speed: 5 m / min Drying oven length: 5 m Drying temperature: 110 ° C. The obtained antifouling layer had a thickness of 5 nm.

The obtained laminated body was evaluated in the same manner as in Example 1. As a result, the coating film of the obtained laminated body was free from uneven appearance such as coating unevenness, vertical wrinkles, and backing. The average value of the minimum reflectance wavelength (nd) of the coating film was 575 nm, and the distribution was ± 4%. Further, the average luminous reflectance defined by the following formula in the visible light range of the laminate was 0.5% or less, which showed an excellent antireflection effect.

[0070]

[Equation 1]

Further, the laminate was subjected to a steel wool resistance test (steel wool # 0000 used, load 250 g / c).
was carried out m ^2, 10 round-trip), the appearance of such as scratches failure was excellent in abrasion resistance not observed. Further, the contact angle of water with respect to the coating film was measured and found to be 110 degrees or more.

(Example 6) In order to carry out antireflection coating on the same cellulose triacetate film as used in Example 3, a high refractive index layer, a low refractive index layer and an antifouling layer were formed in this order as follows. A film was formed to obtain a laminated body.

High Refractive Index Layer Using the same coating liquid as in Example 3, a film was formed on the hard coat layer by the same coating method and coating conditions as in Example 5.

Low Refractive Index Layer Preparation of coating liquid: Toluene was added to an acrylic ultraviolet curable resin (Seika Beam EXY-26S manufactured by Dainichiseika Co., Ltd.),
A coating liquid having a solid content concentration of 2.0% was obtained. Using the obtained coating liquid, the same coating method and coating conditions as in Example 5 were applied, and after drying, a high pressure mercury lamp with an output of 160 W / cm ² was used, and the irradiation time was 10 seconds and the irradiation distance was 100 mm. UV irradiation was performed to form a film on the high refractive index layer.

Antifouling Layer Using the same coating liquid as in Example 5, a film was formed on the low refractive index layer by the same coating method and coating conditions as in Example 5.

The obtained laminated body was evaluated in the same manner as in Example 1. As a result, the coating film of the obtained laminated body was free from appearance defects such as coating unevenness, vertical wrinkles, and backing. The average value of the minimum reflectance wavelength (nd) of the coating film was 600 nm, and the distribution was ± 4%. Further, the average luminous reflectance in the visible light region of the laminate was 1.0% or less, which showed an excellent antireflection effect.

Further, when a steel wool test similar to that of Example 5 was carried out, no external appearance defects such as scratches were observed and the abrasion resistance was excellent. Moreover, the measured values of the contact angle of water with respect to the coating film were all 110 degrees or more.

Comparative Example 1 As shown in FIG.
After applying the coating liquid 7 prepared in step 1 to a gravure roll 8 having a diameter of 100 mm and rotating at a rotation speed of 100 rpm shown in FIG. 2, the doctor blade 9 wipes off the excess coating liquid 7 from the surface of the gravure roll 8. The remaining coating liquid 7 was applied to the cellulose triacetate film 11 similar to that in Example 3, which was pressed against the gravure roll 8 by the rubber roll 10 and moved at a conveying speed of 5 m / min to obtain a laminate. In the obtained laminate, the backing of the coating liquid occurred, and both ends of the cellulose triacetate film were covered on both sides.

Comparative Example 2 Preparation of coating liquid: 1 mol of tetraethoxysilane and 6 mol of water containing 0.036% by weight of hydrogen chloride were added to 4 mol of isopropyl alcohol, and the mixture was stirred at 20 ° C. for 6 hours. Then, a coating liquid having a solid content concentration of 12.0% by weight was obtained. Using the obtained coating liquid, a film was formed on the substrate by the microgravure coating method shown in FIG. 1 under the following coating conditions to obtain a laminate. Substrate type: the same as in Example 1. Micro gravure roll: 200 lines / inch, 20 mm diameter with gravure pattern with depth of 30 μm
Micro gravure roll. Micro gravure roll rotation speed: 30 rpm Coating temperature, substrate transfer speed, drying oven length and drying temperature are
Same as Example 1.

The obtained laminated body was evaluated in the same manner as in Example 1. As a result, about half of the coating films of the obtained laminated body had poor appearance such as cloudiness and coating unevenness, and the layer thickness distribution was ±. It was 10%.

(Comparative Example 3) Isopropyl alcohol was added to the coating liquid prepared in Example 1 to obtain a coating liquid having a solid content concentration of 0.05% by weight. Using the obtained coating liquid, a film was formed on the substrate by the microgravure coating method shown in FIG. 1 under the following coating conditions to obtain a laminate. Substrate type: the same as in Example 1. Micro gravure roll: diameter of 20 mm with gravure pattern with 80 lines / inch and depth of 130 μm
Micro gravure roll. Micro gravure roll rotation speed: 30 rpm Coating temperature, substrate transfer speed, drying oven length and drying temperature are
Same as Example 1.

10 points were sampled from the obtained laminate, and a spectrophotometer (UV-3101P manufactured by Shimadzu Corporation) was sampled.
The reflection spectrum in the visible light region was measured using C).
As a result, the reflection spectrum was almost the same as that of the substrate, and no antireflection effect was observed. From this result, it is estimated that the layer thickness of the formed coating film is extremely thin.

Comparative Example 4 The solid content concentration of the coating liquid (2-perfluorooctylethyltriaminosilane coating agent) for producing the antifouling layer in Example 5 was 4.0% by weight.
A laminated body was obtained in the same manner as in Example 5 except that The antifouling layer of the obtained laminate had a thickness of about 50 nm, and a steel wool resistance test was conducted in the same manner as in Example 5. As a result, many scratches were generated and the appearance was poor.

[0084]

EFFECT OF THE INVENTION The constitution of the present invention 1 is as described above, and is composed mainly of at least one kind of metal alkoxide or at least one kind of ultraviolet curable resin whose viscosity and solid content concentration at the time of application are limited. A coating liquid with limited viscosity and solid content concentration
Since the micro gravure coating method is used for coating on a flexible substrate, there are no defects such as vertical wrinkles and back lines, and the layer thickness distribution is controlled to ± 5 nm or less, specifically about 100 nm. It is possible to obtain a laminate having a layer having a thickness of.

The constitution of the present invention 2 is as described above, and the coating solution of the present invention 1 is applied to a flexible substrate by the microgravure coating method to obtain the number of lines of the gravure pattern and the depth of the gravure pattern. Since the film is formed under the microgravure coating conditions in which the rotation speed of the gravure roll and the conveying speed of the base material are limited, it is possible to obtain a laminate particularly suitable for optical material applications.

The configuration of the present invention 3 is as described above, and S
Since coating is performed using a coating liquid containing at least one kind of alkoxide of i, Ti, Zr, or Al as a main component, it is possible to obtain a laminate particularly suitable for optical material applications.

The constitution of the present invention 4 is as described above, and it is particularly suitable for optical materials since it is applied by using a coating liquid containing an ultraviolet curable resin having a (meth) acrylate functional group as a main component. It is possible to obtain a laminated body.

The constitution of the present invention 5 is as described above, and since a plastic film having a light transmittance of 80% or more in the visible light wavelength region is used as the flexible substrate in the present inventions 1 to 4, It is possible to obtain a laminate that is suitable as a member for device use.

The constitution of the present invention 6 is as described above, and the flexible plastic film of the present invention 5 is provided with a hard coat layer, and the viscosity at the time of coating and the solid content concentration are limited thereon. The coating liquid containing at least one type of metal alkoxide or at least one type of ultraviolet curable resin as a main component is applied under specific coating conditions by a microgravure coating method to obtain a high refractive index layer and a low refractive index layer. Are provided in this order, and further, an antifouling layer having a limited thickness is provided thereon, so that not only a laminated body having a small in-plane distribution of variations in antireflection effect but also excellent is obtained. A laminate having abrasion resistance and antifouling property can be obtained.

The constitution of the present invention 7 is as described above. When the polarizing plate obtained in the present invention 7 is used, it is excellent in visibility without reflection of external light rays, and is excellent in abrasion resistance and stain resistance. A liquid crystal display device can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example of a microgravure coating method.

FIG. 2 is an explanatory diagram of a coating method of Comparative Example 1.

[Explanation of symbols] 1 coating liquid supply unit 2 micro gravure roll 3 coating liquid reservoir 4 doctor blade 5 coating liquid 6 base material

Claims (7)

[Claims] 1. A method for producing a laminate by forming a layer on at least one surface of a flexible substrate, wherein at least one layer of the layer is mainly composed of at least one kind of metal alkoxide or at least one kind of ultraviolet curable resin. As a component, the viscosity during coating is 0.
A method for producing a laminate, which comprises applying a coating solution having a solid content concentration of 0.1 to 10% by weight of 1 to 200 cP by a microgravure coating method, and drying and curing the coating solution. 2. The coating conditions of the microgravure coating method are as follows: the number of lines of the gravure pattern engraved on the gravure roll is 70 to 250 lines / inch, and the depth of the gravure pattern engraved on the gravure roll is 13 to 150 μm.
The method for producing a laminate according to claim 1, wherein m, the gravure roll rotation speed is 5 to 200 rpm, and the substrate transport speed is 1 to 30 m / min. 3. The metal alkoxide is Si, Ti, Z.
The method for producing a laminated body according to claim 1, which is an alkoxide of r or Al. 4. The method for producing a laminate according to claim 1, wherein the ultraviolet curable resin has a (meth) acrylate functional group. 5. The method for producing a laminate according to claim 1, wherein the flexible substrate is a plastic film having a light transmittance in the visible light wavelength range of 80% or more. . 6. A plastic film according to claim 5, wherein (1) a hard coat layer is directly provided on at least one surface of the plastic film,
(2) The coating liquid according to claim 1, 3 or 4 capable of forming a layer having a higher refractive index than the plastic film and the hard coat layer on the hard coat layer.
Coating under the described microgravure coating conditions, drying and curing to provide a high refractive index layer, (3) then having a lower refractive index on the high refractive index layer than the high refractive index layer. The coating liquid according to claim 1, 3 or 4 capable of forming a layer,
Coating under the microgravure coating conditions according to claim 2, drying and curing to provide a low refractive index layer, and (4) further
A method for producing a laminate, comprising providing an antifouling layer having a layer thickness of 1 to 20 nm on the low refractive index layer. 7. A method for producing a polarizing plate, which comprises laminating a polarizing element on the laminate obtained by the method according to claim 6 with or without an intervening layer.