JP2001027879A - Manufacture of laminated sheet for liquid crystal display panel and manufacture of liquid crystal display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet which keeps a translucent plastic film and a base material resin sheet tightly adhered to each other even under a high-temperature atmosphere in a production stage for liquid crystal display panels, obviates the generation of air pockets and ensures the smooth progression of precise work in the production stage of the liquid crystal display panels. SOLUTION: The translucent plastic film 15 is laminated via a tacky adhesive layer 14 to an adhesive sheet which consists of the base material resin sheet 13 and a tacky adhesive layer 14 formed thereon and is so constituted as to securely adhere the tacky adhesive layer to the translucent plastic film 15 for the liquid crystal display panel placed thereon before the irradiation with UV rays and, on the other hand, to lower the adhesive power and to allow the easy peeling of the tacky adhesive layer from the translucent plastic film 15 after the irradiation with the UV rays, and thereafter, these sheets are subjected to a heat treatment.

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 laminated sheet for a liquid crystal display panel used in producing a liquid crystal display panel, and a liquid crystal display using the laminated sheet for a liquid crystal display panel obtained by the method. The present invention relates to a method for manufacturing a panel.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display panel,
Glass, resin sheets, and the like are used for substrates, but the amount of resin sheets used has been gradually increasing due to recent demands for lighter, thinner and smaller electronic devices.

When a liquid crystal display panel is manufactured using a resin sheet, a light-transmitting metal oxide electrode, an alignment film, and the like are formed directly on two resin sheets to form a laminate. After processing, etc., the spacers are sprayed, followed by superposition of these two laminates and sealing of the peripheral part with an adhesive, injection of liquid crystal and sealing of the injection port, lamination of a polarizing plate and a color filter, etc. Had been performed.

However, when a high-precision, large-area liquid crystal display panel is manufactured on a flexible resin sheet, when electrodes are directly formed on the resin sheet as in the conventional case, the base is not provided. Since the material resin sheet is likely to bend, it is difficult to maintain a constant shape in a three-dimensional sense, and therefore, it is not possible to perform highly accurate processing like processing on a glass substrate. There has been a problem that it is difficult to secure the accuracy of alignment and to achieve automation.

[0005] Therefore, an extremely flat translucent plastic film is placed on a predetermined substrate and brought into close contact with the substrate, and various layers such as a translucent metal oxide electrode are formed on the translucent plastic film. The way was being taken. In this method, first, a light-transmitting metal oxide electrode is formed on a light-transmitting plastic film adhered to a substrate, and then an alignment film and the like are formed to form a first laminated substrate. And a spacer is placed on the alignment film. On the other hand, except that the spacers are not sprayed, a second laminated substrate is produced in the same manner as the above method, a sealing agent layer or the like is formed around the second laminated substrate, and the second laminated substrate on which the sealing agent layer is formed is formed. Then, a liquid crystal display panel is manufactured by laminating and bonding a first laminated substrate, and injecting a liquid crystal and sealing an injection port.

The substrate used in the above process does not basically constitute a liquid crystal display panel, and must be removed by peeling off at any stage of the manufacturing process. Therefore, after laminating the second laminated substrate and the first laminated substrate and then bonding and removing the two substrates, or
The substrate is peeled off and removed from one of the laminated substrates in a process before bonding, and after laminating the second laminated substrate and the first laminated substrate, the other laminated substrate is peeled off and removed. Was taking the way.

In the manufacturing process of such a liquid crystal display panel, after a light-transmitting plastic film is brought into close contact with a substrate, a process of removing the substrate from the laminated substrate is performed.
A transparent plastic film must be firmly fixed on the substrate in order to smoothly carry out precise work.

If the translucent plastic film is weakly fixed to the substrate, the translucent plastic film may be wrinkled or broken, making precise work difficult. On the other hand, the base is unnecessary after the injection of the liquid crystal and the sealing of the injection port are performed. Therefore, it is necessary to easily peel the base from the light-transmitting plastic film and the laminated substrate formed thereon. There is.

[0009]

Therefore, when performing various operations on the light-transmitting plastic film, the adhesiveness with the light-transmitting plastic film is high. By irradiating ultraviolet rays, a method was adopted in which the adhesive sheet, which facilitates peeling, was fixed by inserting it between the translucent plastic film and the substrate, but such an adhesive sheet was used. Even in this case, a thin air layer (hereinafter, referred to as an air pocket) is formed between the light-transmitting plastic film and the adhesive sheet in the heating process for forming the alignment film, and the subsequent process requires precision. There is a problem that difficult work becomes difficult.

[0010]

Means for Solving the Problems In view of the above, the present inventors have conducted intensive studies and found that some air trapped between the laminated sheet for a liquid crystal display panel comprising a translucent plastic film and an adhesive sheet. Even when is formed, it has been found that a heat treatment of the laminated sheet for a liquid crystal display panel causes a phenomenon in which an air pocket gradually disappears, and the present invention has been completed.

That is, the method for producing a laminated sheet for a liquid crystal display panel of the present invention comprises a base resin sheet and a pressure-sensitive adhesive layer formed thereon, and a liquid crystal placed thereon before irradiation with ultraviolet rays. An adhesive sheet configured to adhere firmly to a light-transmitting plastic film for a display panel, but to decrease its adhesive force after being irradiated with ultraviolet light, and to be easily peeled off from the light-transmitting plastic film. Then, after laminating the translucent plastic film via the pressure-sensitive adhesive layer, these are heat-treated. Hereinafter, the present invention will be described in detail.

In the method for producing a laminated sheet for a liquid crystal display panel according to the present invention, the liquid crystal display panel comprises a base resin sheet and a pressure-sensitive adhesive layer formed thereon, and is placed thereon before irradiation with ultraviolet rays. Adhesive sheet that is configured so that it adheres firmly to the translucent plastic film for use, but after ultraviolet irradiation, its adhesive strength is reduced and can be easily separated from the translucent plastic film. .

The adhesive sheet comprises a base resin sheet made of a usual material that can transmit ultraviolet rays, and an adhesive layer formed on the base resin sheet, the adhesiveness of which changes when irradiated with ultraviolet rays in a specific wavelength range.

The base resin sheet is not particularly limited as long as it is a resin sheet capable of transmitting ultraviolet rays. Examples thereof include vinyl chloride resin, vinyl chloride / vinylidene chloride copolymer resin, and vinyl chloride / vinyl acetate copolymer. Resin sheets made of resin, polyvinylidene chloride resin, polyolefin, polyvinyl alcohol, polyamide, polyester, polycarbonate, acetyl cellulose and the like can be mentioned.

The pressure-sensitive adhesive layer is preferably composed of, for example, an acrylic resin-based pressure-sensitive adhesive, an ultraviolet-crosslinkable compound, a polymerization initiator, or the like.

The acrylic resin-based pressure-sensitive adhesive includes, for example, a copolymer of an acrylate monomer and another copolymerizable monomer. The copolymer of the acrylate monomer and another copolymerizable monomer uses the acrylate monomer having a low glass transition point as a main monomer to impart tackiness, while the As other copolymerizable monomers, monomers capable of forming a hard polymer having a high glass transition point to impart cohesiveness, and carboxylic acid groups and hydroxyl groups to improve crosslinkability and adhesion And a monomer having a functional group such as amide group, glycidyl group and hydroxyl group.

Examples of the ultraviolet-crosslinkable compound include acrylic or methacrylic esters as oligomers or monomers which are crosslinked by irradiation of ultraviolet rays in a specific wavelength range. Those having an acroyl group or a methacryloyl group are preferred.

Examples of the oligomer include oligoester acrylate, and examples of the monomer include 1,6-hexanediol acrylate, trimethylolpropane triacrylate, and the like.
Ester of polyhydric alcohol such as tetramethylol methane tetraacrylate, dipentaerythritol hexaacrylate and acrylic acid, or 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, dipentaerythritol hexaacrylate An ester of a polyhydric alcohol such as acrylate and methacrylic acid can be exemplified. In addition, urethane acrylate, epoxy acrylate and the like can also be mentioned.

In preparing the pressure-sensitive adhesive layer, for example,
The ultraviolet-crosslinkable compound is added in an amount of 30 to 100 parts by weight based on 100 parts by weight of the acrylic resin-based pressure-sensitive adhesive. In addition,
Parts by weight indicate the percentage of the weight of the solid content.

The above-mentioned pressure-sensitive adhesive layer may further contain a polymerization initiator, a tackifier and the like. The polymerization initiator is used to promote crosslinking of the ultraviolet-crosslinkable compound by ultraviolet irradiation. In the present invention, a conventionally known polymerization initiator can be used. Examples of these polymerization initiators include benzoin alkyl ethers such as benzoin methyl ether and benzoin propyl ether, aromatic oxyketones such as benzoin, benzyl and benzophenone, aromatic ketones, benzyl dimethyl ketal, and polyvinyl benzophenone. be able to.

The tackifier is not particularly limited, and those conventionally used as pressure-sensitive adhesives can be used. Examples of such tackifiers include xylene resins, rosins and polymerized rosins, hydrogenated rosins, modified rosin resins such as rosin esters, terpene resins, terpene phenol resins, terpene resins such as rosin phenol resins, and aliphatic resins. , Aromatic and alicyclic petroleum resins, cumarone resins, styrene resins, alkylphenol resins and the like.

The amount of the polymerization initiator is preferably 1 to 20 parts by weight based on 100 parts by weight of the ultraviolet-crosslinkable compound. For each component constituting the pressure-sensitive adhesive layer, an appropriate amount of an organic solvent for dissolving them, for example, aromatic hydrocarbons, ketones, or a mixture thereof is added and dissolved to form a pressure-sensitive adhesive layer. A solution composition having a uniform composition can be obtained, and the pressure-sensitive adhesive layer can be formed by applying the solution composition on a base resin sheet by a conventionally known method and drying the solution composition. .

The adhesive sheet is firmly adhered to a light-transmitting plastic film placed thereon before irradiation with ultraviolet light, while the adhesive force is reduced after irradiation with ultraviolet light to reduce the light-transmitting plastic film. It is configured so that it can be easily peeled off from the film.

Examples of the translucent plastic film include polycarbonate, polyether sulfone, polyarylate, polyethylene terephthalate, polyethylene-2,6-naphthalate, and polyether / ether ketone.

In the manufacturing process of the liquid crystal display panel, when various layers are formed on the translucent plastic film by using a physical method or a chemical method, various forces are applied to the translucent plastic film. Acts on conductive plastic films.

When forming an alignment film, it is necessary to heat these systems, so that the temperature of the entire system including the adhesive sheet rises.
Even at a temperature of 0 ° C., the adhesive strength between the translucent plastic film and the adhesive sheet is configured to be strong.

However, if only the light-transmitting plastic film is bonded to the above-mentioned adhesive sheet via the pressure-sensitive adhesive layer, an air pocket is formed between the adhesive sheet and the light-transmitting plastic film, and the liquid crystal is formed. In some cases, it may be difficult to perform a precise operation in a manufacturing process of a display panel.

Therefore, in the present invention, after a light-transmitting plastic film is laminated on the above-mentioned adhesive sheet, they are subjected to a heat treatment. By this heat treatment, even if some air pockets are generated, the air pools can be removed. After laminating a translucent plastic film on the adhesive sheet and fixing it to the substrate with an adhesive, heat treatment may be performed.

The conditions of the heat treatment are not particularly limited.
Although the effect of reducing air pockets appears even when heat treatment is performed for several hours at a temperature of 0 ° C. or more, the heat treatment time during heat treatment is more preferably about 10 to 200 hours, and the heat treatment temperature at that time is 40 to 150 hours. C is more preferred.

When laminating, using a heated roll or the like under the conditions of a heating temperature of 50 to 150 ° C. and a pressure of 0.01 to 10 MPa / m under pressure,
By pressing and rotating the roll or the like against the translucent plastic film placed on the adhesive sheet and performing lamination, it is possible to more effectively eliminate the air pool.

Since the laminated sheet for a liquid crystal display panel manufactured in this manner has been subjected to the heat treatment as described above, even at a high temperature of 100 to 200 ° C., the adhesive sheet and the translucent plastic film can be obtained. Are firmly adhered to each other and no air pocket is formed. Adhesive strength between adhesive sheet and translucent plastic film is 40g
/ Inch or more, preferably 40 to 200 g /
More preferably it is inches.

After that, various layers are formed on the translucent plastic film constituting the laminated sheet for the liquid crystal display panel. In this case, too, there is a gap between the translucent plastic film and the adhesive sheet. Therefore, a layer having a correct shape can be formed at a correct position without causing displacement or peeling.

[0033] The adhesive sheet has an adhesive force with the translucent plastic film at room temperature before irradiation with ultraviolet light.
More preferably, it is not less than 00 g / inch. This is because in the process of manufacturing the liquid crystal display panel, various larger forces act at room temperature.

On the other hand, when the adhesive sheet is irradiated with ultraviolet light, the adhesive force between the adhesive sheet and the translucent plastic film is reduced, and the adhesive sheet is easily peeled off from the translucent plastic film. Will be able to do that. It is preferable that the adhesive strength with the translucent plastic film at normal temperature after irradiation with ultraviolet rays is 20 g / inch or less.

As a result of the decrease in the adhesive strength of the adhesive sheet, for example, when the steps of forming a plurality of layers on the translucent plastic film and manufacturing the liquid crystal display panel are completed, for example, By irradiating the adhesive sheet with ultraviolet rays using a high-pressure mercury lamp, the adhesive sheet can be easily peeled off, and the intended laminate or the like for a liquid crystal display panel can be easily obtained.

The method of irradiating the pressure-sensitive adhesive layer with ultraviolet rays is not particularly limited, and a conventionally used method can be used. For example, a xenon lamp, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, or an ultra-high-pressure A method of irradiating for several seconds to several minutes using an ultraviolet light source such as a mercury lamp can be used.

The pressure-sensitive adhesive layer has a thickness of 254 nm of a low-pressure mercury lamp.
It is preferable that the adhesive strength is hardly reduced by ultraviolet rays having a main wavelength of, while the adhesive strength is greatly reduced by ultraviolet rays of a high-pressure mercury lamp having a main wavelength of 365 nm. This is because, in the manufacturing process of the liquid crystal display panel, for example, when patterning a photoresist, ultraviolet rays having a main wavelength of 254 nm from a low-pressure mercury lamp may be irradiated.

Next, a method of manufacturing a liquid crystal display panel using the laminated sheet for a liquid crystal display panel manufactured by the above method will be specifically described. When manufacturing a liquid crystal display panel, first, as shown in FIG. 1 (a), an adhesive sheet comprising a base resin sheet 13 and an adhesive layer 14 is, if necessary, heated and pressed under pressure. The light-transmitting plastic film 15 is laminated via the agent layer 14, and thereafter, these are subjected to a heat treatment at, for example, 40 to 150 ° C. for 10 to 200 hours to produce the laminated sheet 20 for a liquid crystal display panel.

Next, as shown in FIG. 1B, a laminated sheet 20 for a liquid crystal display panel is adhered to a substrate 11 made of glass or the like via an adhesive layer 12. After this, FIG.
(C) As shown in FIG.
A light-transmitting metal oxide electrode 16, an alignment film 17 and the like are formed thereon, and a laminate used for a liquid crystal display panel is manufactured.

In the step shown in FIG.
When forming 7, the part including the adhesive sheet is heated. Usually, when the alignment film 17 is formed, these systems are kept at 100 to 200 ° C. for 1 to 3 hours.

In the present invention, in the step shown in FIG. 1A, the heat treatment is applied to the laminated sheet 20 for a liquid crystal display panel. Therefore, even at such a high temperature, there is no air accumulation between the pressure-sensitive adhesive layer 14 and the translucent plastic film 15, and the two are firmly adhered to each other. As a result, the precise work in the step shown in FIG. 1 (c) can proceed smoothly.

The reason why the adhesive sheet is adhered to the substrate 11 made of a solid such as glass via the adhesive layer 12 is to fix the adhesive sheet to the firm substrate 11. Base resin sheet 1 constituting a functional sheet
When 2 is not too thick and easily bends or wrinkles, it is preferable to bond the adhesive sheet to the base 11.

Next, by irradiating the pressure-sensitive adhesive layer 14 with, for example, ultraviolet light having a main wavelength of 365 nm of a high-pressure mercury lamp, as shown in FIG. The pressure-sensitive adhesive layer 14) can be easily peeled off from the translucent plastic film 15 or the like. There is no particular limitation on the time at which the adhesive sheet is peeled off from the light-transmitting plastic film, and in the step of manufacturing the liquid crystal display panel, the time may be removed as appropriate so that the work proceeds smoothly. Thereafter, a liquid crystal display panel is manufactured as in the conventional case.

[0044]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, regarding the compounding amount of each component in the following Examples and Comparative Examples, those other than the solvent are parts by weight of solid content.

Example 1 First, 100 parts by weight of an acrylic resin-based pressure-sensitive adhesive (manufactured by Toa Gosei Co., Alondac S-1601), 50 parts by weight of an ultraviolet-crosslinkable compound (manufactured by Toa Gosei Co., Aronix M-400), and photopolymerization was started. 1.6 parts by weight of an agent (manufactured by Ciba Specialty Chemicals, Irgacure 500), 16 parts by weight of a tackifier (manufactured by Arakawa Chemical Industries, KE-604), and 33 parts by weight of methyl ethyl ketone were added to the container in the above proportions. By mixing, a solution composition for forming an adhesive layer was prepared.

Next, the obtained solution composition was applied to a thickness of 38
μm polyethylene terephthalate (PET) and dried at 120 ° C. for 1 minute to obtain 20 μm
A pressure-sensitive adhesive layer having a thickness of 2 was formed to prepare an adhesive sheet.
Next, a polycarbonate (PC) film was superimposed on the pressure-sensitive adhesive layer of the produced adhesive sheet so as not to form air bubbles, and was reciprocated 5 times with a 3 kg roller and pressed and adhered thereto. By performing heat treatment for a day,
A laminated sheet for a liquid crystal display panel was obtained.

The resulting laminated sheet for a liquid crystal display panel was tested for adhesive strength at room temperature before irradiation with ultraviolet light, presence or absence of air pockets at 130 ° C. before irradiation with ultraviolet light, and PC at room temperature after irradiation with ultraviolet light. The adhesion to the film was measured and evaluated using the method described below. The results are shown in Table 1.

[0048]Evaluation method  (1) Measurement of adhesive strength before UV irradiation The obtained laminated sheet for a liquid crystal display panel is 25 mm wide and 25 mm long.
A test piece cut to a length of 100 mm was
Using a 1175 type testing machine at room temperature and a tensile speed of 300
A 90 ° peel test of this test piece was performed under the condition of mm / min.
The adhesive strength was measured.

(2) Measurement of air pocket under an atmosphere of 130 ° C. before irradiation with ultraviolet light
mm, the glass was fixed to a fixing glass with a two-component curing type epoxy adhesive, and left for 1 hour to obtain a test piece.

The test piece was placed in an oven at 130 ° C. for 2 hours and then taken out. The presence or absence of air pockets was visually observed using a loupe, and evaluated according to the following criteria. ：: No air pocket is observed at all ×: 1 to 3 air pockets are observed

(3) Measurement of Adhesive Force after Irradiation with Ultraviolet Light A test piece similar to the test piece used at the time of measuring the adhesive force before irradiation with ultraviolet light was prepared, and a main wavelength of 365 μm, 120 W from the polyethylene terephthalate side was prepared. / Cm for 7 seconds. Then, Instron 1175
The test piece was subjected to a 90 ° peel test at room temperature at a tensile speed of 300 mm / min using a mold type testing machine, and the adhesive strength was measured.

Example 2 After an adhesive sheet was prepared in the same manner as in Example 1, a polycarbonate (PC) film was overlaid on the pressure-sensitive adhesive layer of the adhesive sheet so as not to form air bubbles, and a 3 kg roller was used. After reciprocating 5 times and pressing and contacting them,
For 16 hours to obtain a laminated sheet for a liquid crystal display panel. Using this laminated sheet for a liquid crystal display panel, various characteristics were measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 After an adhesive sheet was prepared in the same manner as in Example 1, a polycarbonate (PC) film was overlaid on the pressure-sensitive adhesive layer of the adhesive sheet so as not to form air bubbles, and a 3 kg roller was used. The laminate was pressed and adhered five times to obtain a laminated sheet for a liquid crystal display panel. In addition, this laminate sheet for liquid crystal display panels was not subjected to any heat treatment. Using this laminated sheet for a liquid crystal display panel, various characteristics were measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0054]

[Table 1]

As shown in Table 1 above, since the laminated sheet for a liquid crystal display panel produced in the example was subjected to heat treatment, the base resin sheet and the light-transmitting plastic film were strongly adhered to each other, and the air pool was formed. Does not occur. Therefore, by using this laminated sheet for a liquid crystal display panel, the translucent plastic film does not shift or peel off, and a liquid crystal display panel can be manufactured favorably.

[0056]

According to the method for producing a laminated sheet for a liquid crystal display panel of the present invention, since the above-described structure is employed, the base resin sheet and the light-transmitting plastic film are strongly adhered to each other, and the high temperature in the production process of the liquid crystal display panel is obtained. Even under the atmosphere,
No bubbles or air pockets are generated. as a result,
Precise work in the process of manufacturing the liquid crystal display panel can smoothly proceed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a manufacturing process of a liquid crystal display panel using an adhesive sheet for a liquid crystal display panel of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Base 12 Adhesive layer 13 Base resin sheet 14 Adhesive layer 15 Translucent plastic film 16 Translucent metal oxide electrode 17 Alignment film 20 Lamination sheet for liquid crystal display panels

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideaki Suzuki 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical Co., Ltd. (72) Inventor Hideo Kuroda 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical (72) Inventor Yoshio Taguchi 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical Co., Ltd.F-term (reference) 4F301 AA02 AA17 AA19 AA20 AA25 AA26 AD02 BA21 BE41 BF31 4J040 DF041 FA142 FA262 FA292 GA02 JA09 JB08 JB09 KA14 LA10 MA10 MA11 MB03 NA17 PA30 PA42 5G435 AA12 AA17 BB12 FF01 HH02 KK05

Claims (3)

[Claims] 1. A base resin sheet and a pressure-sensitive adhesive layer formed thereon, which are firmly adhered to a translucent plastic film for a liquid crystal display panel placed thereon before being irradiated with ultraviolet rays. On the other hand, after irradiation with ultraviolet light, the adhesive strength is reduced, and the light-transmitting plastic sheet is formed on the adhesive sheet via the pressure-sensitive adhesive layer so as to be easily peeled off from the light-transmitting plastic film. A method for producing a laminated sheet for a liquid crystal display panel, comprising laminating films and subjecting them to heat treatment. 2. A method for producing a laminated sheet for a liquid crystal display panel, wherein the temperature of the heat treatment is 40 to 150 ° C. and the time of the heat treatment is 10 to 200 hours. 3. A method for manufacturing a liquid crystal display panel, comprising using the laminated sheet for a liquid crystal display panel obtained by the method according to claim 1.