JP2769830B2 - Liquid crystal cell manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for industrially and advantageously producing a liquid crystal cell using a flexible laminate and a base material as intermediate materials.

2. Description of the Related Art A liquid crystal cell required for manufacturing a liquid crystal display panel is formed by forming a transparent electrode on a substrate made of a glass plate or a thick plastic sheet, further forming an alignment film thereon, and then performing a rubbing treatment. The two liquid crystal cell substrates obtained in this manner are disposed so that the transparent electrode sides thereof are opposed to each other with a spacer interposed therebetween, and a liquid crystal is sealed between the two liquid crystal cell substrates and the periphery is sealed.

Problems to be Solved by the Invention The above-described manufacturing process of the liquid crystal cell is, more specifically, a very multi-step process as described below, that is, “substrate cleaning → transparent conductive film deposition → resist coating → developing → etching・ Washing → alignment layer formation → rubbing treatment → sealant printing or common electrode transfer printing → semi-curing → lamination → heat curing → vacuum degassing → liquid crystal injection → injection port sealing '' It must be done in a high environment.

Although these process operations have been automated, as long as a glass plate or a thick plastic sheet is used as a substrate, various restrictions are inevitable in the production line.

For example, taking only one process, the "transparent conductive film deposition" process as an example, the substrate, even if a plastic substrate is used as well as a glass plate, has a suitable rigidity or thickness. Therefore, it is impossible to form a transparent electrode on a substrate by roll-to-roll. So conventionally,
A substrate of a predetermined size is supplied into a vacuum deposition apparatus or a sputtering apparatus to bring it to a high vacuum condition, the vacuum state is released after the vacuum deposition or sputtering is performed, and then the next substrate is supplied into the box. A complicated operation of repeating the same operation is performed.

The present invention has been made in view of such circumstances, and in order to drastically improve productivity and operability, the liquid crystal cell manufacturing process has been rolled.
To provide a method for industrially advantageously producing a liquid crystal cell by using a two-roll to obtain a flexible laminate as an intermediate material, and then using the flexible laminate and a base material. It is the purpose.

Means for Solving the Problems The method for producing a liquid crystal cell of the present invention comprises the steps of: forming a thin film (1a) having a crosslinked resin cured material layer having a retardation value of 50 nm or less and a light transmittance of 60% or more on the cured resin layer side The transparent electrode (1b) is provided on the surface of (2), and the two thin layer materials (1) that can be wound into a roll and have a configuration in which the alignment layer (1c) is further provided thereon,
A flexible laminate for manufacturing a liquid crystal cell in which liquid crystal (2) is sealed between both thin-layer materials (1), (1), and arranged close to each other so that the respective alignment layers (1c) face each other. Using (3), the flexible laminate for manufacturing a liquid crystal cell (3)
Is made of a glass sheet or a plastic sheet that cannot be wound into a roll via an adhesive layer (5), (5), and has a retardation value of 80 nm or less and a light transmittance of 60% or more. The substrate base materials (4) and (4) are laminated and integrated.

 Hereinafter, the present invention will be described in detail.

<Flexible laminate (3) for producing liquid crystal cell> The flexible laminate (3) is an intermediate material for producing a liquid crystal cell, and is composed of a thin layer material (1) / liquid crystal (2). ) /
It has a configuration of a thin layer material (1). Thin layer material (1) is thin film (1
a) / transparent electrode (1b) / alignment layer (1c), the flexible laminate (3) is more specifically formed of [thin film (1a) / transparent electrode (1b) / alignment layer (1c). )] / Liquid crystal (2)
/ [Alignment layer (1c) / transparent electrode (1b) / thin film (1a)].

The production of the flexible laminate (3), that is, the series of steps from the formation of the transparent electrode (1b) to the thin film (1a) to the encapsulation of the liquid crystal (2) can be all performed by roll-to-roll. .

First, as the thin film (1a), the crosslinked resin cured material layer has a retardation value of 50 nm or less (especially 40 nm or less), a light transmittance of 60% or more (especially 80% or more), and is rolled. Various thin films can be used as long as they can be turned. As the thin film (1a), a film manufactured by an arbitrary method such as an extrusion method and a casting method can be used as long as it has the above-mentioned characteristic values.

Since the thin film (1a) is required to be able to be wound into a roll, its thickness is usually 10 to 300 μm, especially 20 to 200 μm.
m, especially from the range of 30-150 μm. However, if it can be wound into a roll, the thickness may be more than 300 μm.

The resin layers constituting the thin film (1a) include a polycarbonate film layer, a polyethersulfone film layer, a polysulfone film layer, a polyarylene ester film layer, a polyparabanic acid resin film layer, an amorphous polyolefin film layer, a cellulose resin film layer, and a crosslinked resin film layer. Examples thereof include a cured resin layer and an air-permeable synthetic resin layer. However, at least the surface on which the transparent electrode (1b) is provided is required to be a crosslinked resin cured material layer.

Here, as the crosslinked resin cured material layer, a layer of a cured product of a crosslinkable resin such as a phenoxy ether-based crosslinkable resin, an epoxy resin, an acrylic resin, a melamine resin, a phenol resin, and a urethane resin may be mentioned. Of these, particularly preferred are layers formed from a composition of a phenoxy ether-based polymer and a crosslinking agent. As the crosslinking agent, a group having a high reaction activity with active hydrogen, for example, an isocyanate group or a carboxyl group A compound having two or more reactive inducing groups (for example, halide, active amide, active ester, acid anhydride, etc.), mercapto group and the like is used.

Examples of the gas-permeable synthetic resin layer include a resin layer containing at least 50 mol% of an acrylonitrile component, a vinyl alcohol component or a vinylidene halide component, and in particular, polyvinyl alcohol or a copolymerized modified product or graft thereof, A polymer having an OH group such as an ethylene-vinyl alcohol copolymer or a graft thereof having an ethylene content of 15 to 50 mol% is important.

In the case of multiple layers, an anchor coating layer, an adhesive layer, and the like can be interposed, if necessary, to increase the adhesion between adjacent layers or to prevent the film from being affected by a solvent during casting.

The crosslinked resin cured material layer, especially the phenoxy ether-based crosslinked resin cured material layer has good adhesion to the transparent electrode (1b) such as ITO, so the thin film (1a) is transparent to the surface of the crosslinked resin cured material layer side. An electrode (1b) will be formed.

Materials for forming the transparent electrode (1b) include Sn,
When metals such as In, Ti, and Pb or oxides thereof are used, and a single metal is formed on the above-mentioned thin film (1a),
If necessary, it can be subsequently oxidized. From the beginning, it is also possible to adopt a method of forming an adhered layer as an oxide layer, but first, a film is formed in the form of a simple metal or a lower oxide,
Then, a means for performing an oxidizing treatment such as heat oxidation or liquid phase oxidation to make it transparent may be employed. When a low-temperature sputtering device is used, the oxidation heating step can be omitted. In addition, a noble metal such as Au, Pt, or Ag may be used in some cases.

 The formation of the transparent electrode (1b) is performed as follows.

First, the thin film (1a) wound around the supply roll and the take-up roll are set in a transparent electrode (1b) forming device such as a vacuum evaporation device or a sputtering device.

One surface of the thin film (1a) (the surface on which the crosslinked resin cured material layer is provided) while bringing the inside of the apparatus into a high vacuum and winding the thin film (1a) around the winding roll while feeding the thin film (1a) from the supply roll. The transparent electrode (1b) is continuously formed.

After the formation of the transparent electrode (1b), the vacuum state in the apparatus is released, and the thin film (1a) with the transparent electrode (1b) wound on the winding roll is taken out.

The layer thickness of the transparent electrode (1b) is often 100 Å or more, preferably 200 Å or more.

After the transparent electrode (1b) is formed on the thin film (1a) as described above, the formation of the alignment layer (1c) and the rubbing treatment are performed according to a conventional method to obtain the thin layer material (1), or , Resist coating, development, etching / cleaning, alignment layer (1c) formation,
A rubbing treatment is performed to obtain a thin layer material (1).

Subsequently, sealant printing or common electrode transfer printing and semi-cure are performed on the thin layer material (1), and the two thin layer materials (1) are laminated and heat-cured so that the respective alignment layers (1c) sides face each other. , Vacuum degassing, liquid crystal (2) injection, and injection port sealing are performed in this order.

In the present invention, these series of steps are performed by a roll-to-roll process to obtain a flexible laminate (3) for producing a liquid crystal cell.
Get.

FIG. 1 is a schematic sectional view of a flexible laminate (3) for producing a liquid crystal cell according to the present invention.

<Liquid Crystal Cell> Then, base materials (4) and (4) for the substrate are laminated on both surfaces of the above-described flexible laminate (3) for producing a liquid crystal cell via adhesive layers (5) and (5). By integrating, a target liquid crystal cell is obtained.

FIG. 2 is a schematic sectional view of a liquid crystal cell obtained by the method of the present invention.

As the base material (4) for a substrate, a glass plate or a plastic sheet that cannot be wound into a roll is used, and its retardation value is preferably 80 nm or less and light transmittance is preferably 60% or more.

Thickness of plastic sheet is 400 ~ 5000μ
m (preferably 500 to 4000 μm) is appropriate, but may be thicker or thinner in some cases.

Among the substrate base materials (4), particularly preferred are polycarbonate, polymethyl methacrylate, polyether sulfone, polyarylene ester, polyacrylate (polymethyl methacrylate and polymethyl acrylate), amorphous polyolefin and the like.

Lamination integration is performed using an adhesive (including a pressure-sensitive adhesive, a heat-sensitive adhesive, and the like), and the adhesive includes a urethane-based, acrylic-based, polyester-based, cyanoacrylate-based, olefin-based, epoxy-based, or silicone-based adhesive. An adhesive such as is used.

In addition, due to the solvent contained in these adhesives,
Depending on the type of the thin film (1a) of the thin layer material (1) or the base material (4) for the substrate, the surface may be affected. In addition, ordinary adhesives are inconvenient in terms of sticking operation, and pressure-sensitive adhesives have a problem that they are not completely cured like ordinary adhesives.

Therefore, when the thin film (1a) or the base material for a substrate (4) does not have solvent resistance, an aqueous or alcohol-flexible thermosetting adhesive or an alcohol-soluble ultraviolet-curing adhesive may be used as the adhesive. preferable.

The water-based thermosetting adhesive is a polymer that has been polymerized by at least one type of a bonding group selected from the group consisting of an ester bond, an amide bond, a urethane bond, and an ether bond. A composition comprising a polymer having a hydrophilic group in a molecule in an amount sufficient to dissolve or disperse and a curing agent is suitably used. Examples of the aqueous medium include water and a mixed solvent of water and an alcohol, and examples of the hydrophilic group include sulfonic acid metal bases, carboxyl groups, primary amine groups, secondary amine groups, and tertiary amine groups. And quaternary ammonium groups. Representative examples of the polymer having a hydrophilic group in the molecule include a polyester resin having the above hydrophilic group, a polyamide resin having the above hydrophilic group, a polyurethane resin having the above hydrophilic group, and a polyester urethane having the above hydrophilic group. Resin, ionic polymer complex comprising a mixture of polyethylene, polyacrylic acid and modified starch, and the like. The term “polymer” is a concept including an oligomer or a prepolymer.

As with the water-based thermosetting adhesive, a thermosetting adhesive that is soluble in or dilutable with alcohol can also be used.

Examples of the alcohol-soluble UV-curable adhesive include a non-functional polymer and a polyfunctional or / and monofunctional monomer, a functional prepolymer, a functional prepolymer and a polyfunctional or / and monofunctional monomer,
A composition in which a polymerization initiator is added to a functional prepolymer, a non-functional polymer, a polyfunctional or / and monofunctional monomer, a functional prepolymer and a non-functional polymer, and further an additive is added as necessary. Is used. Here, as the non-functional polymer, urethane polymer, amide polymer, acrylic polymer,
Examples include polyester-based polymers.

Among the alcohol-soluble UV-curable adhesives described above, urethane acrylate-based one-part UV-curable adhesives using isopropanol as a solvent are most preferable. As a commercial product, Takeda Pharmaceutical Co., Ltd. There is Takelight UV-500 made by the company.

The composition of the phenoxy ether-based polymer and the cross-linking agent described above as the cross-linked resin cured product for forming the thin film (1a) is:
When the thin film (1a) or the base material (4) for a substrate has solvent resistance, the above composition is used because it has a tacky-adhesive property such that it has a tack by drying and is completely cured by heating under pressure. Can be used as an adhesive.

When the above-mentioned adhesive (a water-based or alcohol-soluble thermosetting adhesive, an alcohol-soluble ultraviolet-curable adhesive, an adhesive made of a composition of a phenoxy ether-based polymer and a crosslinking agent, etc.) is used as the adhesive, The adhesive is stable after coating and drying on one of the thin film (1a) of the thin layer material (1) or the base material (4) for the substrate unless heated or irradiated with ultraviolet light. , It is possible to adhere to the other member. Further, after both are press-bonded, if heat curing or ultraviolet irradiation is performed, the adhesive is completely cured, and permanent bonding between the thin layer material (1) and the base material for substrate (4) is achieved. In other words, the adhesive can be adhered like a conventional adhesive while being an adhesive, and can achieve permanent adhesion.

Although the thickness of the adhesive layer (5) formed of these adhesives is not particularly limited, it is 1 to 50 μm, especially 3 to 30 μm on a dry basis.
It is often set to μm.

Function and Effect of the Invention In the present invention, first, a laminate (3) having flexibility
And then, on both surfaces thereof, base materials for substrates (4), (4)
Are laminated and integrated to produce a liquid crystal cell. The main part of the liquid crystal cell is made first, and finally the reinforcing part is made. Thin film (1a)
Has a cured crosslinkable resin layer, and the transparent electrode (1b) is formed on the surface of the cured crosslinkable resin layer side, so that the adhesion of the transparent electrode (1b) is good.

The production of the flexible laminate (3), that is, the series of steps from the formation of the transparent electrode (1b) to the thin film (1a) to the encapsulation of the liquid crystal (2) must be performed by "roll-to-roll". It is possible to use a glass plate or a plastics substrate with a thickness that cannot be rolled as before,
"Transparent conductive film deposition → resist coating → development → etching
Production compared to the case of performing various processes of washing → forming an alignment layer → rubbing treatment → printing of a sealant or common electrode transfer printing → semi-curing → lamination → heating and curing → vacuum degassing → liquid crystal injection → injection port sealing Dramatically improved. Therefore, a desired liquid crystal display panel can be manufactured efficiently and at low cost.

EXAMPLES Next, the present invention will be further described with reference to examples. In the following, "parts" and "%" are used except for light transmittance (%),
It is shown on a weight basis.

Example 1 <Thin film (1a)> Thickness 80 μm, retardation value 12 nm, light transmittance 90
% Of a 40% solids aqueous dispersion (NeoRezR-9317, manufactured by Kusumoto Kasei Co., Ltd.) containing 100% polyester urethane as a main component in a 100% polycarbonate film, and a water-soluble epoxy-based curing agent (World Rock, manufactured by Kyoritsu Chemical Industry Co., Ltd.) X-2030) 5
The anchor agent mixed with the parts was applied using a wire round doctor and dried at 90 ° C. for about 5 minutes to form an aqueous anchor coating layer having a thickness of about 1 μm.

Ethylene content on this aqueous anchor coating layer
16 parts of a 32 mol% ethylene-vinyl alcohol copolymer,
A coating solution having a composition consisting of 48 parts of water and 32 parts of n-propanol was applied and dried at 70 to 110 ° C. to form an air-permeable synthetic resin layer having a thickness of about 10 μm.

Then, 40 parts of a phenoxy ether-based resin (manufactured by Toto Kasei Co., Ltd.), 40 parts of methyl ethyl ketone, 20 parts of cellosolve acetate, and 75 parts of tolylene isocyanate-trimethylolpropane adduct were placed on the air-permeable synthetic resin layer.
% Solution (Coronate L manufactured by Nippon Polyurethane Co., Ltd.)
A curable resin solution having a composition of 40 parts was applied using an applicator, dried at 80 ° C. for 4 minutes, and then heat-treated at 130 ° C. for 20 minutes to form a phenoxy ether-based crosslinked polymer layer.

Thereby, the thickness of the layer structure consisting of polycarbonate film / water-based anchor coating layer / air-permeable synthetic resin layer / phenoxy ether-based crosslinked polymer layer is 105 μm,
A thin film (1a) having a multilayer structure with a retardation value of 8 nm and a light transmittance of 92% was obtained.

<Thin Film (1a) with Transparent Electrode (1b)> The thin film (1a) obtained above was set in a sputtering device while being wound on a supply roll, and a winding roll was also set in the sputtering device.

The inside of the apparatus is brought to a high vacuum, and while the thin film (1a) is wound up on a take-up roll while being unwound from the supply roll, ITO is continuously applied to the surface of the thin film (1a) on the phenoxyether-based crosslinked polymer layer side. Sputtering, thickness 300
An Angstrom transparent electrode (1b) was formed. Thereafter, the inside of the apparatus was returned to normal pressure, and the thin film (1a) with the transparent electrode (1b) wound on the winding roll was taken out.

<Flexible laminate (3)> After the transparent electrode (1b) is formed on the thin film (1a) as described above, the formation of the alignment layer (1c) and the alignment layer (1
The rubbing treatment of c) was carried out using a roll-to-roll method to obtain a thin layer material (1).

In addition, resist coating, development, etching / washing, alignment layer (1c) formation, and rubbing treatment were all performed on the other thin film (1a) with the transparent electrode (1b) using a roll-to-roll process. (1) was obtained.

Seal material printing or common electrode transfer printing on one thin layer material (1), semi-curing by roll-to-roll, and then laminating the other thin layer material (1), heat curing, vacuum degassing Each step of injecting the liquid crystal (2) and sealing the injection port was carried out by roll-to-roll.

Thereby, the thin material (1) / the liquid crystal (2) / the thin material (1), that is, [thin film (1a) / transparent electrode (1b) / alignment layer (1c)] / liquid crystal (2) / [alignment] Layer (1c) / Transparent Electrode (1b) / Thin Film (1a)] to obtain a flexible laminate (3) with good productivity.

<Liquid crystal cell> Thickness 1000 μm, retardation value 8 nm, light transmittance 9
A thin film (1) is placed on one side of each of two base materials (4) and (4) made of 4% polymethyl methacrylate sheet.
a) Apply an aqueous thermosetting adhesive solution with the same composition as the anchor agent used for formation using an applicator, and apply at 80 ° C.
For 15 minutes to form adhesive layers (5) and (5) having a slightly tacky thickness of 10 μm.

The adhesive layer (5) side of each of the two plates composed of the substrate base material (4) / adhesive layer (5) obtained above is placed on both sides of the above-mentioned flexible laminate (3). Laminated and crimped, temperature 120
The adhesive layer (5) is cured by heating at 20 ° C for 20 minutes.
(5) was almost completely cured. As a result, a desired liquid crystal cell was obtained.

Example 2 Thickness 1000 μm, retardation value 8 nm, light transmittance 9
An alcohol-soluble UV-curable adhesive solution (Takelite UV-500 manufactured by Takeda Pharmaceutical Co., Ltd.) was applied to one side of each of two base materials (4) and (4) made of a 4% polymethyl methacrylate sheet. An anaerobic UV-curable resin based on acrylic urethane as the main component, isopropanol solution, one-pack type, solid content 40%, Zahn viscosity 18 seconds / 25 ° C) is applied using an applicator and dried at 80 ° C for 2 minutes. hand,
An adhesive layer (5) having a slight tack of 10 μm thickness,
(5) was formed.

The adhesive layer (5) side of each of the two plates composed of the base material for substrate (4) / adhesive layer (5) obtained above is the same flexible laminate (3) as in Example 1. On both sides and crimped.

While moving the laminated sheet on the conveyor, ultraviolet light was irradiated from both sides under the conditions of an irradiation amount of 120 W / cm ² and an irradiation time of 10 seconds, and the adhesive layers (5) and (5) were almost completely cured. . As a result, a desired liquid crystal cell was obtained.

Examples 3 to 4 As a base material (4) for a substrate, a glass plate having a thickness of 1.5 mm (Example 3), a thickness of 800 μm, a retardation value of 10 nm, a light transmittance of 93%, a refractive index of 1.55, and a water absorption of 0.01% Hereinafter, a liquid crystal cell was manufactured by repeating Example 1 except that an amorphous polyolefin (APO manufactured by Mitsui Petrochemical Industries, Ltd.) sheet (Example 4) having a softening temperature of 150 ° C. and a pencil hardness of 2H was used.

Example 5 A thin film (1a) was obtained in the same manner as in Example 1 except that a polyethersulfone film having a thickness of 100 μm, a retardation value of 14 nm, and a light transmittance of 90% was used instead of the polycarbonate film. Example 1 was repeated to produce a flexible laminate (3) and further a liquid crystal cell.

Example 6 As a thin film (1a), a phenoxyether-based crosslinked polymer layer / water-based anchor coating layer / polycarbonate film / water-based anchor coating layer / phenoxyether-based crosslinked polymer layer has a thickness of 120 μm and a retardation value of 16 nm. Using a film having a light transmittance of 89%, a flexible laminate (3) and a liquid crystal cell were produced in the same manner as in Example 1 below.

Example 7 ADCOTE, an alcohol-soluble adhesive manufactured by Toyo Morton Co., Ltd., was used as an adhesive for bonding the base materials (4) and (4) for a substrate composed of a polymethyl methacrylate sheet to the flexible laminate (3). -70 (base agent, solid content 65%) and ADCOTE-
Example 1 was repeated except that 9H3 (curing agent, solid content: 65%) was used at a weight ratio of 100: 2 to produce a liquid crystal cell.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a flexible laminate (3) for producing a liquid crystal cell according to the present invention. FIG. 2 is a schematic sectional view of a liquid crystal cell obtained by the method of the present invention. (1) ... a thin layer material that can be wound into a roll shape (1a) ... a thin film, (1b) ... a transparent electrode, (1c) ... an alignment layer, (2) ... a liquid crystal, (3) ... ... Flexible laminate for manufacturing liquid crystal cell (4) ... Base material for substrate (5) ... Adhesive layer

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-300221 (JP, A) JP-A-57-20718 (JP, A) JP-A-64-17020 (JP, A) JP-A-58-58 140718 (JP, A) JP-A-63-262681 (JP, A) JP-A-56-42211 (JP, A) JP-A-63-71829 (JP, A) JP-A-61-41122 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/1333

Claims (1)

(57) [Claims] A transparent electrode (1b) is provided on a surface of a thin film (1a) having a crosslinked resin cured material layer having a retardation value of 50 nm or less and a light transmittance of 60% or more on the crosslinked resin cured material layer side. Two thin layer materials (1) that can be wound into a roll having a configuration in which an alignment layer (1c) is provided thereon are arranged close to each other so that the respective alignment layer (1c) sides face each other.
A flexible laminate (3) for manufacturing a liquid crystal cell, in which a liquid crystal (2) is sealed between the two thin layer materials (1) and (1), is used. Is made of a glass sheet or a plastic sheet that cannot be wound into a roll via an adhesive layer (5), (5), and has a retardation value of 80 nm or less and a light transmittance of 60% or more. A method for manufacturing a liquid crystal cell, comprising: laminating and integrating substrate base materials (4) and (4).