JP2000227516A - Method for producing epoxy-based substrate sheet and substrate sheet thereof - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To be useful for forming a liquid crystal cell having excellent thinness.
To efficiently form a substrate on which a retardation sheet, a gas barrier layer, and an epoxy-based cured sheet overlap. SOLUTION: While running a long retardation sheet (1) sequentially, coating liquids (22, 32) are sequentially spread on the sheet and formed into a film (23, 33). A method of manufacturing an epoxy-based substrate sheet for continuously manufacturing a substrate (6) in which a gas barrier layer (2) and an epoxy resin cured layer (3) are successively adhered and superimposed on the retardation sheet, and a phase difference for optical compensation An epoxy-based substrate sheet in which a sheet and an epoxy resin cured layer are in close contact with each other via a gas barrier layer without the interposition of an adhesive layer. [Effects] Epoxy-based substrate sheets of various physical properties with excellent optical properties, thinness, gas barrier properties, etc. can be continuously manufactured by simple operations, and mass production speed and thickness can be easily controlled, and thin and liquid crystal that does not easily deteriorate in quality. Cells can be formed efficiently.

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 superposition type epoxy substrate sheet excellent in mass productivity and an epoxy substrate sheet excellent in thinness and suitable for forming a liquid crystal cell or the like.

[0002]

2. Description of the Related Art Conventionally, as an epoxy-based substrate sheet in which a retardation sheet is provided on a cured sheet of an epoxy resin subjected to a gas barrier treatment, the cured sheet is laminated on the retardation sheet via an adhesive with the gas barrier treated surface. What was done was known. Such a retardation sheet is provided for the purpose of compensating and eliminating, for example, a coloring phenomenon or the like caused by a retardation due to the liquid crystal. In addition, gas barrier processing
When used as a cell substrate or the like, it is performed for the purpose of preventing the encapsulating material such as liquid crystal from being altered.

However, there has been a problem that the production efficiency is poor due to the need for the step of bonding via an adhesive as described above, and that the thickness is increased due to the interposition of the adhesive layer, thereby lowering flexibility. Also, when the epoxy resin coating liquid is spread directly on a casting support such as an endless belt or roll to form a cured sheet, the adhesion to the support is so strong that it cannot be peeled or collected, or it cures when peeling. It is difficult to continuously produce an epoxy resin cured sheet due to problems such as damage to the sheet, and the casting method using a mold has a problem that the production efficiency of the cured sheet is poor.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for efficiently forming a substrate on which a retardation sheet, a gas barrier layer and an epoxy-based cured sheet are superimposed, and is useful for forming a liquid crystal cell having excellent thinness. The task is to develop a system board sheet.

[0005]

According to the present invention, a long retardation sheet is sequentially run, and a coating liquid is sequentially spread on the long retardation sheet and formed into a film. A method for manufacturing an epoxy-based substrate sheet, comprising continuously manufacturing a substrate on which a gas barrier layer and an epoxy resin cured layer are successively adhered and superimposed, and a retardation sheet for optical compensation and an epoxy resin cured layer forming a gas barrier layer. The present invention provides an epoxy-based substrate sheet characterized in that the epoxy-based substrate sheets are formed in close contact with each other without an adhesive layer therebetween.

[0006]

According to the manufacturing method of the present invention, the phase difference sheet, the gas barrier layer, and the epoxy resin cured layer adhere to each other through a series of simple operations of spreading the coating liquid on the phase difference sheet to form a film. It is possible to continuously and efficiently manufacture the superposed epoxy-based substrate sheets, and it is possible to easily control the mass production speed and the thickness of the sheets obtained by adjusting the moving speed of the retardation sheet and the spread amount of the coating liquid.

[0007] In addition, due to the reinforcing effect due to the close contact with the retardation sheet and the gas barrier layer, a brittle epoxy resin can be used, and an epoxy resin cured layer having excellent rigidity can be formed. You can get a sheet. Furthermore, the obtained epoxy-based substrate sheet can be easily separated from the support through the interface with the retardation sheet, so that the casting support is hardly damaged at the time of recovery and has a long service life. Even if a support having a rough surface is used and the state is not reflected, the surface state based on the retardation sheet can be ensured, and since a peeling step for releasing the adhesion state is not performed, damage such as optical defects does not easily occur.

[0008] In addition, an epoxy-based substrate sheet which is easy to be reduced in thickness, and which is excellent in flexibility and gas barrier properties, can form a close-contact superimposed state of a retardation sheet, a gas barrier layer and a cured epoxy resin layer without the interposition of an adhesive layer. It can be easily obtained, and it can be used as a cell substrate to efficiently form a thin liquid crystal cell or the like in which liquid crystal or the like is hardly deteriorated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method according to the present invention comprises the steps of sequentially running a long retardation sheet, successively spreading a coating solution on the sheet in a sheet form, and forming the sheet into a film. An epoxy-based substrate sheet in which a gas barrier layer and an epoxy resin cured layer are successively adhered and superimposed on a phase difference sheet is continuously manufactured.

FIG. 1 shows an example of the above manufacturing process. This shows a continuous production method by a casting method, wherein 1 is a long retardation sheet, 2 is a gas barrier layer, 21 is a die for spreading the coating liquid in a sheet form, and 3 is an epoxy resin. Reference numeral 31 denotes a die for spreading the epoxy resin coating liquid into a sheet, 23.33 denotes a film forming apparatus, and 4 denotes an endless belt. Reference numeral 6 denotes an epoxy-based substrate sheet, which is formed by laminating a gas barrier layer 2 and an epoxy resin cured layer 3 on a retardation sheet 1 in sequence without interposition of an adhesive layer as shown in FIG.

In the above, the phase difference sheet 1 is sequentially fed out from the winding roll 11 via the endless belt 4 which is rotated and driven in the direction of a thick arrow by a driving drum 41 and a driven drum 42, for example, from 0.1 to 50 m. / M, especially at a speed of 0.2 to 5 m / min, and a coating liquid for forming a gas barrier layer is sequentially spread thereon in the form of a sheet via a die 21 to form a spread layer 22. Processing unit 23
To form a gas barrier layer 2 and adhere to the retardation sheet during the film formation process.

Subsequently, an epoxy resin coating liquid is sequentially spread on the gas barrier layer 2 through a die 31 in the form of a sheet, and the spread layer 32 is cured through a film forming apparatus 33 to cure the epoxy resin. The epoxy-based substrate sheet 6 is continuously produced while being in close contact with the gas barrier layer 2 on the retardation sheet 1 during the curing process.
2 through a cutting step (not shown).

In the above, as the film forming processing devices 23 and 33, for example, an appropriate processing device such as a heating type or a light irradiation type capable of forming a film of a target coating liquid can be used. In the above-described example, the coating layers of the coating liquid are each formed into a film. However, the present invention also employs a method of forming a superposed layer of the coating liquid developing layers and then forming them all at once. be able to. From the viewpoint of controlling the thickness of each layer to be formed, it is preferable to perform the film forming treatment for each spread layer of the coating liquid as in the above example.

The retardation sheet may be, for example, a stretched film made of various resins, a film having a controlled refractive index in the thickness direction, a liquid crystal polymer oriented film or its oriented layer depending on the intended use of the epoxy substrate sheet. An appropriate long body such as that supported by the above can be used, and there is no particular limitation.

Accordingly, the retardation characteristics of the retardation sheet are also arbitrary. For example, various wave plates such as a half-wave plate and a quarter-wave plate, and compensation for coloring and viewing angle due to birefringence of a liquid crystal layer, etc. The optical compensator may have an appropriate phase difference according to the intended use. Further, the retardation sheet may be a single-layered material, or a laminated material in which two or more layers of the same or different types of retardation layers are laminated for the purpose of controlling optical characteristics such as retardation. You may.

Rather than maintaining the retardation characteristics, it has heat resistance enough to withstand the temperature at which the coating solution for forming the gas barrier layer or the epoxy resin coating solution is formed into a film, the intended use of the epoxy-based substrate sheet, and the like. Those can be preferably used. Further, those having excellent flexibility are preferable from the viewpoints of handleability and production efficiency of the target product.

When used for forming a liquid crystal display device, by taking into account heat treatment in the manufacturing process, a phase difference of a resin having a glass transition temperature of 120 ° C. or more, such as polycarbonate, polysulfone, or polyethersulfone, is used. A film or the like can be preferably used. The thickness of the retardation sheet differs depending on the intended retardation characteristics and the like, but is generally 1 mm or less for the purpose of thinning and flexibility.
Especially, it is 5 to 500 μm, especially 10 to 300 μm.

Further, in the above, the retardation sheet is used in combination with the casting support of the retardation sheet for the purpose of preventing the surface from being damaged due to contact with the casting support made of an endless belt or the like in the manufacturing process. It can also be used in a state where a protective sheet is provided on the side in contact. As the protective sheet, an appropriate one such as a resin film, a foamed sheet, paper, or a nonwoven fabric can be used.

The protective sheet may be integrated with the retardation sheet by, for example, an adhesive treatment through an adhesive layer or the like. Preferably, it is in a state where it can be easily separated.
Although the thickness of the protective sheet can be determined as appropriate, it is generally 1 mm or less, especially 5 to 500 μm, for the purpose of thinning and flexibility.
m, especially 10 to 300 μm.

The coating liquid for forming a gas barrier layer spread on the retardation sheet can be prepared by using an appropriate material that can be liquefied so as to prevent permeation of a desired gas. Incidentally, in a liquid crystal cell, if moisture or oxygen permeates the cell substrate and enters the cell, there is a possibility that the appearance of the liquid crystal deteriorates due to deterioration, bubbles are formed, and the transparent conductive film pattern is disconnected.

Therefore, in the case of a liquid crystal cell, it is important to prevent permeation of water vapor and oxygen gas, and a material capable of preventing permeation of such gas is used. As the material, an inorganic material such as silica may be used, but generally, a polymer is used in terms of ease of forming a film by a coating method and deformation resistance.

As the above-mentioned polymer, any suitable polymer which can prevent the permeation of water vapor or oxygen gas as described above can be used.
For example, polyvinyl alcohol, a partially saponified product thereof, an ethylene / vinyl alcohol copolymer, polyacrylonitrile, polyvinylidene chloride, or the like having a small oxygen permeability coefficient is used. In particular, a vinyl alcohol-based polymer can be preferably used from the viewpoint of gas barrier properties, water diffusibility, and uniformity of water absorption.

The coating liquid for forming a gas barrier layer made of a polymer may be one or two of a method in which a polymer solution is prepared using an appropriate solvent capable of dissolving a polymer to be used, such as an aqueous solution of a vinyl alcohol-based polymer. It can be prepared by making at least one kind of forming material into a state where it can be fluidized and developed by using a solvent as necessary.

The coating liquid can be spread by an appropriate method such as a curtain coating method, a roll coating method, a wire bar coating method, an extrusion coating method, or a spray coating method. In particular, in the casting method via a die or the like, the extrusion coating method can be preferably applied from the viewpoint of coating efficiency and the like.

The thickness of the gas barrier layer to be formed can be appropriately determined and is not particularly limited. Generally, transparency and color prevention,
The thickness is preferably 15 μm or less, more preferably 13 μm or less, and particularly preferably 1 to 10 μm, from the viewpoints of gas barrier properties, thinning, and flexibility of the obtained epoxy-based substrate sheet.

In preparing the gas barrier layer or the epoxy resin coating liquid spread on the coating liquid for forming the gas barrier layer, an epoxy resin and its curing agent are used, and if necessary, a curing accelerator and a leveling agent are used. Agents are used in combination. The epoxy resin is not particularly limited, and an appropriate epoxy resin may be used according to the intended use of the epoxy-based substrate sheet to be formed, a desired curing treatment method such as heat curing or light irradiation curing, and the like.

Examples of the epoxy resin include bisphenol A such as bisphenol A type, bisphenol F type, bisphenol S type and hydrogenated type thereof, novolak type such as phenol novolak type and cresol novolak type, and triglycidyl isocyanate. Nitrogen-containing ring type such as nurate type and hydantoin type, alicyclic type and aliphatic type, aromatic type such as naphthalene type and glycidyl ether type, low water absorption type such as biphenyl type, dicyclo type, ester type and ether ester And modified forms thereof.

Epoxy resins which can be preferably used from the viewpoint of optical characteristics such as transparency do not contain a conjugated double bond such as a benzene ring and have good discoloration preventing properties, such as an alicyclic type. Usually, the epoxy equivalent is 100 to 100.
An epoxy resin having a softening point of 0.degree. C. or lower at 0 is preferably used from the viewpoint of physical properties such as flexibility and strength of the obtained epoxy-based substrate sheet. More than the point of obtaining an epoxy resin coating liquid excellent in coatability and spreadability into a sheet form, etc., the temperature is lower than the temperature at the time of coating, especially, a two-pack mixed type liquid which shows a liquid state at room temperature is preferable. Can be used.

One or more epoxy resins can be used, and liquid and solid epoxy resins can be used in combination. The strength and heat resistance can be improved by using a solid epoxy resin, and the viscosity of the coating liquid can be adjusted. In particular, the viscosity of the coating liquid can be increased and the thickness of the spreading layer can be easily controlled. Can be.

On the other hand, the curing agent is not particularly limited.
One or more appropriate curing agents depending on the epoxy resin can be used. Incidentally, examples thereof include organic compounds such as tetrahydrophthalic acid and methyltetrahydrophthalic acid, hexahydrophthalic acid and methylhexahydrophthalic acid, ethylenediamine and propylenediamine, diethylenetriamine and triethylenetetramine,
Examples thereof include amine compounds such as amine adducts, metaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone.

Amide compounds such as dicyandiamide and polyamide; hydrazide compounds such as dihydrazide; methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole and isopropylimidazole, 2,4-dimethylimidazole and phenylimidazole; Imidazole compounds such as undecylimidazole, heptadecylimidazole and 2-phenyl-4-methylimidazole are also examples of the curing agent.

Further, methylimidazoline and 2-ethyl-
Imidazoline compounds such as 4-methylimidazoline, ethylimidazoline and isopropylimidazoline, 2,4-dimethylimidazoline and phenylimidazoline, undecylimidazoline and heptadecylimidazoline, 2-phenyl-4-methylimidazoline and other phenolic compounds And urea-based compounds and polysulfide-based compounds are also examples of the curing agent.

In addition, acid anhydride compounds and the like are also examples of the above-mentioned curing agent. In view of work environment due to low irritation, high temperature durability due to improvement in heat resistance of the obtained cured layer, and discoloration prevention. Is preferably such an acid anhydride-based curing agent. Examples include phthalic anhydride and maleic anhydride, trimellitic anhydride and pyromellitic anhydride, nadic anhydride and glutaric anhydride, tetrahydrophthalic anhydride and methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and Methyl hexahydrophthalic anhydride,
Methyl nadic anhydride or dodecenyl succinic anhydride,
Examples thereof include dichlorosuccinic anhydride, benzophenonetetracarboxylic anhydride, and chlorendic anhydride.

Among them, colorless or pale yellow like phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride,
An acid anhydride-based curing agent having a molecular weight of about 140 to about 200 can be preferably used.

The amount of the curing agent to be used can be appropriately determined according to the type thereof, the epoxy equivalent of the epoxy resin, and the like, and can be the same as in the case of ordinary epoxy resin curing. Incidentally, in the case of the above-mentioned acid anhydride-based curing agent, from the viewpoint of preventing the hue and moisture resistance of the resulting cured layer from decreasing, 0.5 equivalent to 1 equivalent of epoxy group is used.
-1.5 equivalents, especially 0.6-1.4 equivalents, especially 0.7-
It is preferable to use an acid anhydride-based curing agent at a ratio of 1.2 equivalents. When other curing agents are used alone or in combination of two or more, the amount of use can be in accordance with the above-mentioned equivalent ratio.

The curing accelerator used as required is not particularly limited, either. For example, tertiary amines, imidazoles, or the like depending on the type of epoxy resin or curing agent.
Appropriate ones such as quaternary ammonium salts, organic metal salts, phosphorus compounds and urea compounds can be used alone or in combination of two or more.

By using a curing accelerator, the curing speed can be accelerated to shorten the required curing time, and the required line length from development to curing can be reduced to a fraction of that required when no accelerator is used. be able to. Therefore, the amount of the curing accelerator can be appropriately determined according to the acceleration effect and the like,
In general, the amount is preferably 0.05 to 7 parts by weight, more preferably 0.1 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight, per 100 parts by weight of the epoxy resin from the viewpoint of the anti-tarnish property.

The leveling agent, if necessary, may be used to cure the spread layer of the epoxy resin coating solution in contact with air when the epoxy resin coating solution is cured. It is blended for the purpose of forming a smooth surface by preventing the occurrence of such a situation, for example, a silicone-based or acrylic-based, appropriate surfactant that can reduce the surface tension of various surfactants such as fluorine-based One or more of these can be used.

In preparing the epoxy resin coating solution, an antioxidant such as a phenol-based, amine-based, organic sulfur-based, or phosphine-based antioxidant, which may be further incorporated into the epoxy resin cured product as required. , Silicones, alcohols and other modifiers, foam inhibitors, hydroxyl-containing compounds, dyes, discoloration inhibitors, UV absorbers and other suitable additives. The above-mentioned foaming inhibitor is added for the purpose of preventing air bubbles which cause a decrease in optical properties from being mixed into the obtained cured layer, and a polyhydric alcohol such as glycerin can be preferably used.

The epoxy resin coating liquid can be prepared by mixing the components with a solvent if necessary so that the components can be fluidized and developed. The development of the coating liquid can be based on the above-described coating liquid for forming a gas barrier layer.
Therefore, in the casting method via a die or the like, the extrusion coating method can be preferably applied from the viewpoint of coating efficiency and the like.

The thickness of the epoxy resin cured layer to be formed can be determined as appropriate, but is generally 100 to 1 in terms of rigidity such as bending strength, surface smoothness, low phase difference, thinness and lightness.
000 μm, especially 150-800 μm, especially 200-50
0 μm is preferred. Further, it is preferable that the thickness accuracy is ± 10% or less from the viewpoint of optical use and the like. The thickness accuracy can be achieved by, for example, a method of maintaining the surface of the retardation sheet as horizontal as possible in the process of forming the epoxy resin cured layer. Such a method is preferably applied to the above-described process of forming the gas barrier layer to increase the thickness accuracy.

The continuum of the formed epoxy-based substrate sheet is cut to an appropriate size through an appropriate cutting means such as a laser beam, an ultrasonic cutter, dicing, or a water jet as necessary according to the purpose of use. It can also be collected.

The epoxy-based substrate sheet according to the present invention can be preferably used for various applications such as a retardation plate. In particular, it can be preferably used for optical applications, such as a substrate for a liquid crystal cell, which is required to withstand high-temperature treatment and to be excellent in bending strength and lightness because of its excellent optical characteristics and heat resistance.

In particular, an epoxy-based substrate sheet in which a retardation sheet for optical compensation, a gas barrier layer and an epoxy resin cured layer are in close contact with each other, is excellent in thinness without an adhesive layer interposed therebetween, and is excellent in a liquid crystal cell. It can be preferably used as a cell substrate or the like for forming.

[0045]

EXAMPLE 1 100 parts (parts by weight, the same applies hereinafter) of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, methylhexahydrophthalic anhydride 1
25 parts, tetra-n-butylphosphonium o, o-diethyl phosphorodithioate 3.75 parts, glycerin 2.
25 parts and 0.07 part of a silicone-based surfactant (leveling agent, manufactured by Kusumoto Kasei Co., Ltd., Dispalon LS-009) were stirred and mixed, and aged at 49 ° C. for 90 minutes to prepare an epoxy resin coating liquid.

Next, the casting method illustrated in FIG.
While running at a constant speed of 0.5 m / min a long retardation sheet made of a stretched polycarbonate film having a thickness of 0.5 m, a 5.5% by weight aqueous solution of polyvinyl alcohol is continuously passed through the die at a rate of 7.6 g / min. And spread it in a sheet form, and the spread layer is heated at 60 ° C. for 10
After heating and drying for minutes, the film was formed into a film, and a 3 μm-thick gas barrier layer made of polyvinyl alcohol adhered to the retardation sheet was formed.

Subsequently, the above-mentioned epoxy resin coating liquid was continuously discharged from the die at a rate of 100 g / min onto the gas barrier layer, cast and developed into a sheet, and the developed layer was passed through a heating device. Heat cured at 120 ° C for 30 minutes,
An epoxy-based substrate sheet in which an epoxy resin cured layer having a thickness of 400 μm was tightly superimposed on the gas barrier layer was continuously obtained.

The epoxy-based substrate sheet described above maintains the retardation characteristics of the retardation sheet satisfactorily. When the oxygen permeability of the sheet was measured by the oxirant method in accordance with ASTM D-3985 at 40 ° C. and 43% RH (the same applies hereinafter), 0.2 cc / m ² · 24
It was time / atm.

Example 2 A retardation sheet, a gas barrier layer having a thickness of 3 μm and a cured epoxy resin layer having a thickness of 400 μm were used in the same manner as in Example 1 except that a stretched polysulfone film having a thickness of 60 μm was used as the retardation sheet. Epoxy-based substrate sheets in close contact with each other were continuously obtained. This sheet maintains the retardation characteristics of the retardation sheet well, and has an oxygen permeability of 0.2.
It was cc ^{/ m} 2 · 24 hours · atm.

Comparative Example An epoxy sheet in which a retardation sheet and a cured epoxy resin layer having a thickness of 400 μm were directly adhered was continuously obtained in the same manner as in Example 1 except that the gas barrier layer was not provided. The oxygen permeability of this sheet was 80 cc / m ² · 24 hours · atm.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an example of a manufacturing process.

FIG. 2 is a cross-sectional view of an example of an epoxy-based substrate sheet.

[Explanation of symbols]

 6: Epoxy-based substrate sheet 1: Phase difference sheet 2: Gas barrier layer 3: Epoxy resin cured layer 21, 31: Die 22: Spread layer of coating liquid for forming gas barrier layer 32: Spread layer of epoxy resin coating liquid 23, 33: Film forming equipment

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kiichi Shimohira 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Minoru Miyatake 1-1-1, Shimohozumi, Ibaraki-shi, Osaka No. 2 Nitto Denko Corporation F-term (reference) 2H049 BA06 BA07 BA25 BB25 BB42 BB62 BC09 BC22 4F100 AK21B AK45C AK53A AR00B AR00C BA03 BA07 BA10A BA10C CC00A CC00B EH461 EH462 EJ082 EJ421 J02JEJBJ02J01J02B

Claims (3)

[Claims] 1. A method in which a long retardation sheet is sequentially run, and a coating liquid is sequentially spread on the long retardation sheet to form a film, and a gas barrier layer is formed on the retardation sheet. A method for manufacturing an epoxy-based substrate sheet, comprising continuously manufacturing a substrate on which an epoxy resin cured layer is sequentially adhered and overlapped. 2. The method according to claim 1, wherein the retardation sheet is a single layer or a laminate of two or more layers of a resin having a glass transition temperature of 120 ° C. or higher, and the gas barrier layer is a polymer film;
A method for producing an epoxy-based substrate sheet in which the thickness of a cured epoxy resin layer is 100 μm or more. 3. An epoxy-based substrate sheet wherein an optical compensation retardation sheet and an epoxy resin cured layer are closely adhered to each other via a gas barrier layer without an adhesive layer interposed therebetween.