JPH08286181A - Adhesive composition for liquid crystal display device - Google Patents

Abstract

PURPOSE: To provide an adhesive compsn. used for sticking the liquid crystal cell and polarizing plate of a liquid crystal display device. CONSTITUTION: This adhesive compsn. is used for adhering substrates 2, 2' and the polarizing plate 6 at the time of producing the liquid crystal display device including the liquid crystal cell 1 formed by providing one surface of the substrates 2, 2' with a liquid crystal layer 5 via transparent electrodes 3, 3' and oriented layers 4, 4' and the polarizing plate 6 adhered to the other surface of the substrates 2, 2'. This adhesive compsn. for the liquid crystal display device is a photosetting adhesive consisting essentially of at least one kind selected from a group consisting of (1) an ethylene-vinyl acetate copolymer, (2) a copolymer of ethylene, vinyl acetate and acrylate and/or methacrylate monomer, (3) a copolymer of ethylene and vinyl acetate and maleic acid and/or maleic anhydride, (4) a copolymer of ethylene and acrylate and/or methacrylate monomer and maleic acid and/or maleic anhydride and (5) an ionomer resin formed by conjugating the molecules of an ethylene-methacrylic acid copolymer to each other with metal ions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition used in the field of optoelectronics for bonding a liquid crystal cell and a polarizing plate of a liquid crystal display device for the purpose of display utilizing the response of liquid crystal molecules by an electric field. Regarding things.

[0002]

2. Description of the Related Art Conventionally, the alignment layers of two substrates having a transparent electrode and an alignment layer formed on one surface thereof are opposed to each other, and a liquid crystal layer is interposed therebetween, and A liquid crystal display (LCD) having a polarizing plate bonded to the other surface of the substrate is widely used. In this case, a technique of using an acrylic pressure-sensitive adhesive for bonding the substrate and the polarizing plate is known (Japanese Patent Laid-Open No. 57-1952).
08, JP-A-3-12471).

Here, the polarizing plate for a liquid crystal display device is one in which both sides of a polarizing film are covered and protected by protective films. The protective film is a cellulose film,
Polyester resin film, polyacrylic resin film, polycarbonate film polyether sulfone, etc. are used, while the surface substrates of liquid crystal cells are becoming diverse, such as glass, polycarbonate, polyester resin, polyarylate resin, etc. After bonding the both, durability is required for various treatments and practical use. However, in the current acrylic pressure-sensitive adhesive, the adhesive strength depends on the bonding pressure, and the heat resistance after bonding,
There is an undeniable decrease in adhesive strength due to the accelerated heat and humidity resistance test, and peeling, floating and foaming occur at the adhesive interface. In other words, when heat treatment such as transparent electrode formation and alignment treatment is applied to the substrate surface of the laminated body in which the polarizing plate and the surface substrate of the liquid crystal cell are adhered and integrated, the heat resistance of the conventional acrylic pressure-sensitive adhesive is high. Therefore, there is a problem that peeling of the adhesive interface occurs due to the low value.

The present invention has been made in view of the above circumstances, and since it has excellent initial adhesive strength and excellent heat resistance, it can sufficiently withstand heat treatment and is excellent in durability, and has excellent durability and polarization. An object is to provide an adhesive composition for a liquid crystal display device, which is used for adhesion to a plate.

[0005]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies to achieve the above object, the present inventors have found that ethylene-vinyl acetate is used for adhesion between the substrate of the liquid crystal cell and the polarizing plate. Copolymers, copolymers of ethylene with vinyl acetate and acrylate and / or methacrylate monomers, copolymers of ethylene with vinyl acetate, maleic acid and / or maleic anhydride, ethylene with acrylates and / or methacrylates Main component is at least one polymer selected from the group consisting of a copolymer of a system monomer and maleic acid and / or maleic anhydride, and an ionomer resin in which ethylene-methacrylic acid copolymer has intermolecular bonds with metal ions. When the photo-curable adhesive is used, the adhesive is a photo-curable polymer containing a polymer with excellent transparency and weather resistance. Because of the adhesive,
The initial adhesive strength is high, and it is possible to bond the polarizing plate to the polarizing plate. Also, since this adhesive has excellent heat resistance, it can withstand heat-related treatments and The inventors have found that it is possible to provide a polarizing plate in which a surface substrate is integrated, and have completed the present invention.

Therefore, the present invention manufactures a liquid crystal display device including a liquid crystal cell in which a liquid crystal layer is provided on one surface of a substrate through a transparent electrode and an alignment layer, and a polarizing plate adhered to the other surface of the substrate. In this case, in the adhesive composition used for adhering the substrate and the polarizing plate, the adhesive composition is an ethylene-vinyl acetate copolymer, or a copolymer of ethylene, vinyl acetate and an acrylate-based and / or methacrylate-based monomer. A copolymer of ethylene with vinyl acetate and maleic acid and / or maleic anhydride; a copolymer of ethylene with an acrylate and / or methacrylate monomer and maleic acid and / or maleic anhydride; ethylene-methacrylic acid copolymer Main component is at least one polymer selected from the group consisting of ionomer resins in which the molecules of the polymer are bound by metal ions. To provide a liquid crystal display device adhesive composition, which is a light curable adhesive.

Hereinafter, the present invention will be described in more detail. The adhesive composition according to the present invention comprises an ethylene-vinyl acetate copolymer as a main component, an ethylene / vinyl acetate / acrylate and / or methacrylate monomer copolymer. A copolymer of ethylene with vinyl acetate and maleic acid and / or maleic anhydride; a copolymer of ethylene with an acrylate and / or methacrylate monomer and maleic acid and / or maleic anhydride; ethylene-methacrylic acid copolymer It is a photocurable adhesive using at least one polymer selected from the group consisting of ionomer resins in which the molecules of the polymer are bound by metal ions.

When an ethylene-vinyl acetate copolymer is used as the polymer, the ethylene-vinyl acetate copolymer preferably has a vinyl acetate content of 10 to 50% by weight, more preferably 14 to 45% by weight. %.
If the vinyl acetate content is lower than 10% by weight, the transparency and optical uniformity of the photocured adhesive will not be sufficient, while if it exceeds 50% by weight, the transparency and optical uniformity will be good. The strength and durability of the adhesive layer tend to be significantly reduced.

Further, the copolymer comprising ethylene, vinyl acetate, and an acrylate-based and / or methacrylate-based monomer preferably has a vinyl acetate content of 1 or less.
0 to 50% by weight, more preferably 14 to 45% by weight is used. If the vinyl acetate content is lower than 10% by weight, the transparency and optical uniformity of the photocured adhesive will not be sufficient, while if it exceeds 50% by weight, the transparency and optical uniformity will be good. The strength and durability of the adhesive layer tend to be significantly reduced. Further, the content of the acrylate and / or methacrylate monomer is 0.0
It is preferably from 1 to 10% by weight, more preferably from 0.05 to 5% by weight. When the content of the monomer is less than 0.01% by weight, the effect of improving the adhesive strength is lowered, while when it exceeds 10% by weight, the processability may be lowered.

The acrylate-based and / or methacrylate-based monomers that can be used are monomers selected from acrylic acid ester or methacrylic acid ester-based monomers. Acrylic acid or methacrylic acid and 1 to 20 carbon atoms, particularly 1 to Ester with 18 unsubstituted or substituted aliphatic alcohols having a substituent such as an epoxy group is preferable, and examples thereof include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, and glycidyl methacrylate.

Further, the copolymer of ethylene, vinyl acetate, maleic acid and / or maleic anhydride preferably has a vinyl acetate content of 10 to 50% by weight, more preferably 14 to 45% by weight. Stuff used. If the vinyl acetate content is lower than 10% by weight, the transparency and optical uniformity of the photocured adhesive will not be sufficient,
On the other hand, when it exceeds 50% by weight, transparency and optical uniformity are improved, but the strength and durability of the adhesive layer tend to be significantly reduced. The content of maleic acid and / or maleic anhydride is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight. If this content is less than 0.01% by weight, the effect of improving the adhesive strength will be reduced, while if it exceeds 10% by weight, the workability will be reduced.

The copolymer of ethylene, an acrylate and / or methacrylate monomer and maleic acid and / or maleic anhydride preferably has an acrylate compound content of 10 to 50% by weight, more preferably. 14 to 45% by weight is used. If the content of the acrylate compound is lower than 10% by weight, the transparency and optical uniformity of the photocured adhesive will not be sufficient, while if it exceeds 50% by weight, the transparency and optical uniformity will be good. However, the strength and durability of the adhesive layer tend to be significantly reduced. Further, the content of maleic acid and / or maleic anhydride is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight. If the content is less than 0.01% by weight, the effect of improving the adhesive strength is reduced, while if it exceeds 10% by weight, the processability may be reduced.

As the acrylate-based and / or methacrylate-based monomers, the same ones as mentioned above can be mentioned.

Further, an ionomer resin in which the molecules of the ethylene-methacrylic acid copolymer are bonded with a metal ion (hereinafter referred to as an ethylene-methacrylic acid ionomer resin).
Is used, the ethylene-methacrylic acid ionomer resin having a methacrylic acid content of 1 to 30% by weight, more preferably 5 to 25% by weight is used. If the methacrylic acid content is less than 1% by weight, the ionic crosslinking effect will be reduced, and the adhesive strength will be reduced, and if it exceeds 30% by weight, the processability may be significantly reduced.

The metal ions used for the ethylene-methacrylic acid ionomer resin are metal ions such as sodium, zinc, magnesium and lithium, and the ionization degree by the metal ions is preferably 5 to 80%. , And more preferably 7 to 70%. If the ionization degree is less than 5%, the transparency is significantly reduced, and 8
If it exceeds 0%, the workability may be significantly lowered.

A photosensitizer is added to cure the photocurable adhesive according to the present invention. Examples of usable photosensitizers include benzoin, benzophenone, benzoin methyl ether and benzoin ethyl ether. , Benzoin isopropyl ether, benzoin isobutyl ether, dibenzyl, 5-nitroacenaphthene, hexachlorocyclopentadiene, paranitrodiphenyl, paranitroaniline, 2,4,6-trinitroaniline,
1,2-benzanthraquinone, 3-methyl-1,3-
Diaza-1,9-benzathlon and the like,
These may be used alone or in combination of two or more.

The addition amount of the photosensitizer in the present invention is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymer.

A silane coupling agent may be added to the adhesive composition of the present invention as an adhesion promoter. Examples of the silane coupling agent include vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy. Propyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (Aminoethyl) -γ-
There are aminopropyltrimethoxysilane and the like, and one of these may be used alone or two or more of them may be used in combination. The addition amount of these silane coupling agents is usually 0.01 to 5 parts by weight per 100 parts by weight of the polymer.

Further, in order to improve and adjust the physical properties (mechanical strength, optical properties, adhesiveness, heat resistance, moist heat resistance, weather resistance, crosslinking rate) of the adhesive composition of the present invention, etc. The compound containing an acryloxy group, a methacryloxy group or an allyl group can be added.

Most commonly used compounds for this purpose are acrylic acid or methacrylic acid derivatives such as their esters and amides. In this case, as the ester residue, in addition to alkyl groups such as methyl, ethyl, dodecyl, stearyl and lauryl, cyclohexyl group, tetrahydrofurfuryl group, aminoethyl group, 2
-Hydroxyethyl group, 3-hydroxypropyl group, 3
-Chloro-2-hydroxypropyl group and the like. Further, esters of acrylic acid or methacrylic acid with a polyfunctional alcohol such as ethylene glycol, triethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, pentaerythritol and the like are also used. Acrylamide is a typical amide. Examples of the allyl group-containing compound include triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl maleate, and the like. One kind or a mixture of two or more kinds thereof is used as a polymer 100% by weight. 0.1 to 50 parts by weight,
It is preferably used by adding 0.5 to 30 parts by weight. 5
If it exceeds 0 parts by weight, workability and film-forming property at the time of preparation of the adhesive may be deteriorated, and if it is less than 0.1 parts by weight, the effect of improving mechanical strength may be deteriorated.

Further, a hydrocarbon resin may be added to the adhesive composition of the present invention for the purpose of improving workability and workability such as bonding. In this case, the added hydrocarbon resin may be a natural resin type or a synthetic resin type. As the natural resin type, rosin, rosin derivative and terpene type resin are preferably used. For rosin, gum resins, tall oil resins and wood resins can be used. As a rosin derivative, rosin is hydrogenated, heterogenized,
Polymerized, esterified, or metal chloride can be used. As the terpene-based resin, terpene-based resins such as α-pinene and β-pinene, and terpene-phenolic resins can be used. Further, other natural resins such as dammar, cobal and shellac may be used. On the other hand, petroleum-based resins, phenol-based resins, and xylene-based resins are preferably used in the synthetic resin system. In petroleum resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin,
Copolymer petroleum resin, hydrogenated petroleum resin, pure monomer petroleum resin, and coumarone indene resin can be used. As the phenol resin, an alkylphenol resin or a modified phenol resin can be used. As the xylene-based resin, a xylene resin or a modified xylene resin can be used.

The amount of the above-mentioned hydrocarbon resin added is appropriately selected, but it is preferably 1 to 200 parts by weight, more preferably 5 to 150 parts by weight, based on 100 parts by weight of the polymer.

In addition to the above additives, the adhesive composition of the present invention may contain a small amount of an ultraviolet absorber, an antiaging agent, a dye, a processing aid and the like. In addition, in some cases, a small amount of additives such as silica gel, calcium carbonate, and fine particles of silicon copolymer may be included.

In the adhesive composition of the present invention, the above polymer and the above additives are uniformly mixed and kneaded by an extruder, a roll or the like, and then a film forming method such as calender, roll, T-die extrusion or inflation. It can be used by forming a film into a predetermined shape. In film formation, embossing may be performed in order to prevent blocking and facilitate degassing during pressure bonding with a polarizing plate protective film or a liquid crystal cell.
In addition, the above-mentioned polymer and the above-mentioned additive are uniformly dissolved in a solvent that does not affect the protective film or the liquid crystal cell surface substrate, are evenly applied to the surface of the film, and are temporarily pressure-bonded, and then are irradiated with light to be bonded. Can be cured.

The adhesive composition of the present invention is applied to the liquid crystal display device as shown in FIG. 1, that is, the transparent electrodes 3, 3'on one side.
A liquid crystal cell 1 in which two substrates 2 and 2'having alignment layers 4 and 4'are arranged so that the alignment layers 4 and 4'are opposed to each other, and a liquid crystal layer 5 is interposed between them; In the manufacture of the liquid crystal display device including the polarizing plate 6 laminated on the other surface of the substrate 2 and the analysis plate 7 laminated on the other surface of the other substrate 2 ', the substrates 2 and 2'and the polarizing plate 6 are used. It is used to bond and. In this case, the polarizing plate 6 is usually formed by covering and protecting both surfaces of the polarizing film 6'with protective films 6 "and 6" as shown in FIG. 6 ″ is bonded to the substrates 2 and 2 ′. After such adhesion, a liquid crystal display device can be manufactured by a conventional method such as forming a transparent electrode on the entire surface of the substrate and further performing an alignment treatment.

The type of the above substrate can be appropriately selected, and examples thereof include glass, polycarbonate, polyester resin,
Examples thereof include polyarylate resin and polyether sulfone resin. Further, as a protective film for a polarizing plate adhered to this substrate, a cellulose-based film, a polyester resin, a polyacrylic resin film, a polycarbonate film, a polyether sulfone is used. A phone or the like can be exemplified.

The photocurable adhesive of the present invention can be cured by irradiating the laminate with ultraviolet rays using a mercury lamp or the like. Further, in order to accelerate the curing, the laminated body may be preheated to about 40 to 120 ° C. and irradiated with ultraviolet rays. In this case, first, the polarizing film is interposed between the protective film and the adhesive of the present invention,
0.01 to 2 at 50 to 120 ° C., particularly 70 to 100 ° C.
0 kgf / cm ^2, in particular 2 to 20 minutes at a pressure of 0.1 to 10 / cm ^2, after pressurizing the heating in particular 5 to 10 minutes, it is recommended to perform the photocuring. The irradiation amount of ultraviolet rays is not particularly limited, but it is preferably 1.0 μW / cm ² or more.

[0028]

Since the adhesive composition according to the present invention is a photocurable adhesive containing the above polymer as a main component, it is excellent in transparency and weather resistance. Further, since it has a cross-linking structure with a photosensitizer and an acryloxy group-containing compound, a methacryloxy group-containing compound, and an allyl group-containing compound which are further added as necessary, heat resistance, moist heat resistance and transparency are improved.
Further, the addition of the silane coupling agent improves the adhesiveness associated with the curing, and the initial adhesive strength and the adhesive strength with excellent thermal stability can be obtained. Due to these actions, reliability such as heat resistance is dramatically improved as compared with conventional acrylic pressure-sensitive adhesives. Along with this, a laminated body in which a polarizing plate and a liquid crystal cell surface substrate are bonded and integrated. When heat treatment such as transparent electrode formation and orientation treatment is performed on the substrate surface, the conventional acrylic adhesive has low heat resistance and thus peels off at the adhesive interface. By using the composition, it is possible to provide a polarizing plate in which a liquid crystal cell surface substrate that can withstand heat treatment is also integrated.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1] 2.0 parts by weight of benzoyl isopropyl ether and γ-methacrylic acid were added to 100 parts by weight of an ethylene-vinyl acetate copolymer (EVA; manufactured by Tosoh Corporation, Ultracene 760, vinyl acetate content 42%). Roxypropyltrimethoxysilane (Shin-Etsu Silicone, KB
M503) 0.5 part by weight and triallyl isocyanurate (manufactured by Nippon Kasei Co., Ltd., TAIC) 2.0 parts by weight were mixed to prepare a solution uniformly dissolved in toluene so that the resin concentration was 20% by weight. Then, this solution was uniformly applied onto a triacetate film by using a roll coater, and the dried film was pressure-bonded to a polycarbonate film while being deaerated, and this was irradiated with ultraviolet rays on a 4 kW high-pressure mercury lamp for 30 minutes on each side for a total of 1 minute for lamination. Body A is obtained.

Example 2 A laminated body B using glass in place of the polycarbonate film in Example 1 was obtained by the same method.

Example 3 A laminate C was obtained in the same manner as in Example 1 except that a polyester film was used instead of the triacetate film and glass was used instead of the polycarbonate film.

Comparative Example A mixture of 95 parts by weight of ethyl acrylate and 5 parts by weight of acrylic acid was polymerized in toluene,
To this, 1 part by weight of polyisocyanate was added to obtain an acrylic pressure-sensitive adhesive. This was applied onto a triacetate film using a roll coater, dried, and pressure-bonded to a polycarbonate film under a pressure of 0.5 kgf / cm ² while degassing, to obtain a laminate D.

Next, a 180 ° peel test was conducted on the laminates of Examples 1 to 3 and Comparative Example under different temperature conditions.
The results are shown in Table 1.

[0035]

[Table 1]

Example 4 Benzoyl isopropyl ether was added to 100 parts by weight of ethylene-vinyl acetate-glycidyl methacrylate copolymer (Sumitomo Chemical Co., Ltd., Bondfast 2A, vinyl acetate content 8%, glycidyl methacrylate content 3%). 2.0 parts by weight, γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd., KBM503) 0.5 parts by weight, and triallyl isocyanurate (manufactured by Nippon Kasei Co., Ltd., TAIC) 2.0 parts by weight were mixed to prepare a resin. A solution uniformly dissolved in toluene was prepared to a concentration of 10% by weight. Then, this solution was uniformly applied onto a triacetate film by using a roll coater, and the dried film was pressure-bonded to a polycarbonate film while degassing, and this was applied to a 4 kW high-pressure mercury lamp on one side 3
A layered product A was obtained by irradiating ultraviolet rays for 0 minutes each for a total of 1 minute.

[Example 5] A laminate B using glass in place of the polycarbonate film in Example 4 was obtained by the same method.

Example 6 A laminate C was obtained in the same manner as in Example 4, except that a polyester film was used instead of the triacetate film and glass was used instead of the polycarbonate film.

Next, a 180 ° peel test was conducted on the laminates of Examples 4 to 6 and Comparative Example under different temperature conditions.
Table 2 shows the results.

[0040]

[Table 2]

[Example 7] Ethylene / vinyl acetate / maleic anhydride copolymer (MODIC manufactured by Mitsubishi Chemical Industry Co., Ltd.)
E-100H, vinyl acetate content about 20%, maleic anhydride content about 0.5%) to 100 parts by weight, benzoyl isopropyl ether 2.0 parts by weight, γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd., K
BM503) 0.5 part by weight and triallyl isocyanurate (manufactured by Nippon Kasei Co., Ltd., TAIC) 1.0 part by weight are mixed,
After kneading with a roll at 80 ° C, a calender gives a film thickness of 100
The film was formed to a thickness of μm. The obtained film was sandwiched between a triacetate film and a polycarbonate film, and after temporarily pressure-bonded in a 90 ° C. oven while degassing in a vacuum bag,
This was irradiated with a 4 kW high-pressure mercury lamp on one side for 30 seconds with ultraviolet rays for a total of 1 minute to obtain a laminate A.

Example 8 A laminate B using glass in place of the polycarbonate film in Example 7 was obtained by the same method.

Example 9 A laminate C using a polyester film in place of the triacetate film and glass in place of the polycarbonate film in Example 7 was obtained by the same method.

Next, a 180 ° peel test was conducted on the laminates of Examples 7 to 9 and Comparative Example under different temperature conditions.
The results are shown in Table 3.

[0045]

[Table 3]

[Example 10] Ethylene-ethyl acrylate-maleic anhydride copolymer (L, manufactured by Sumitomo Chemical Co., Ltd.)
X4110, ethylene content 91%, ethyl acrylate content 8%, maleic anhydride content 1%) 100 parts by weight, benzoyl isopropyl ether 2.0 parts by weight, γ
-Methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone, KBM503) 0.5 part by weight, triallyl isocyanurate (manufactured by Nippon Kasei Co., TAIC) 1.0
After mixing parts by weight and kneading with a roll at 80 ° C., a calender was used to form a film having a thickness of 100 μm. The obtained film was sandwiched between a triacetate film and a polycarbonate film, temporarily depressurized in a vacuum bag in a 90 ° C. oven, and then irradiated with ultraviolet rays on a 4 kW high pressure mercury lamp for 30 minutes on each side for a total of 1 minute. A laminate A was obtained.

[Example 11] A laminate B using glass in place of the polycarbonate film in Example 10 was obtained by the same method.

[Example 12] A laminate C using a polyester film in place of the triacetate film and glass in place of the polycarbonate film in Example 10 was obtained in the same manner.

Next, the laminates of Examples 10 to 12 and Comparative Example were subjected to a 180 ° peel test under different temperature conditions. The results are shown in Table 4.

[0050]

[Table 4]

Example 13 Ethylene-sodium methacrylate ion type ionomer resin (Mitsui DuPont Polychemical Co., Ltd., Himilan 1856, methacrylic acid content 5%, Na ionization degree 40%) 100
2.0 parts by weight of benzoyl isopropyl ether
Parts by weight, γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone, KBM503) 0.5 parts by weight, triallyl isocyanurate (manufactured by Nippon Kasei Co., TA
(IC) 1.0 part by weight was mixed and kneaded with a roll at 80 ° C., and then formed into a film having a thickness of 100 μm by a calendar. The obtained membrane was sandwiched between a triacetate film and a polycarbonate film and degassed in a vacuum bag.
After temporary pressure bonding in an oven at 0 ° C., a 4 kW high-pressure mercury lamp was irradiated with ultraviolet rays for 30 minutes on each side for a total of 1 minute to obtain a laminate A.

[Example 14] A laminate B using glass in place of the polycarbonate film in Example 13 was obtained by the same method.

Example 15 A laminate C using a polyester film in place of the triacetate film and glass in place of the polycarbonate film in Example 13 was obtained by the same method.

Next, the laminates of Examples 13 to 15 and Comparative Example were subjected to a 180 ° peel test under different temperature conditions. The results are shown in Table 5.

[0055]

[Table 5]

As can be seen from the above results, in the laminate D using the acrylic pressure-sensitive adhesive, the adhesive strength is remarkably lowered as the temperature rises. Therefore, when a process for aligning the liquid crystal is performed on the surface of each type of laminate, the heat cannot be endured, and the adhesive interface may float or peel. On the other hand, the laminate using the adhesive of the present invention,
It can be processed even at a high temperature of 70 ° C. without breaking its integrated structure. In addition, a humidity and heat resistance test (50 ° C × 95
After visually inspecting the appearance of various laminates after (% RH × 500 hr), the laminate D using the acrylic pressure-sensitive adhesive showed floating due to foaming at the adhesive interface.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a liquid crystal display device.

FIG. 2 is a cross-sectional view showing an example of a polarizing plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal cell 2,2 'Substrate 3,3' Transparent electrode 4,4 'Alignment layer 5 Liquid crystal layer 6 Polarizing plate 6'Polarizing film 6' 'Protective film 7 Analyzing plate

 ─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 7-25711 (32) Priority date Hei 7 (1995) February 14 (33) Country of priority claim Japan (JP) (31) Priority Claim number Japanese Patent Application No. 7-25712 (32) Priority date Hei 7 (1995) February 14 (33) Country of priority claim Japan (JP)

Claims (9)

[Claims] 1. A substrate for manufacturing a liquid crystal display device comprising a liquid crystal cell in which a liquid crystal layer is provided on one surface of a substrate via a transparent electrode and an alignment layer, and a polarizing plate adhered to the other surface of the substrate. In the adhesive composition used for adhesion between
This adhesive composition is an ethylene-vinyl acetate copolymer; a copolymer of ethylene, vinyl acetate and an acrylate-based and / or methacrylate-based monomer; a copolymerization of ethylene, vinyl acetate, maleic acid and / or maleic anhydride. Copolymers; copolymers of ethylene and acrylate-based and / or methacrylate-based monomers with maleic acid and / or maleic anhydride; from the group consisting of ionomer resins in which the ethylene-methacrylic acid copolymers are bound with metal ions between the molecules. An adhesive composition for a liquid crystal display device, which is a photocurable adhesive containing at least one polymer selected as a main component. 2. The photocurable adhesive comprises 0.1 to 10 parts by weight of a photosensitizer and 0.01 to 5 parts by weight of a silane coupling agent to 100 parts by weight of a polymer. The adhesive composition for a liquid crystal display device according to claim 1. 3. The photocurable adhesive is obtained by adding 0.1 to 50 parts by weight of at least one of an acryloxy group-containing compound, a methacryloxy group-containing compound and an allyl group-containing compound to 100 parts by weight of a polymer. The adhesive composition for a liquid crystal display device according to claim 1 or 2. 4. The liquid crystal according to claim 1, wherein the photocurable adhesive comprises 1 to 200 parts by weight of a hydrocarbon resin with respect to 100 parts by weight of the polymer. Adhesive composition for display device. 5. The adhesive composition for a liquid crystal display device according to claim 1, wherein the polymer is an ethylene-vinyl acetate copolymer, and the vinyl acetate content is 10 to 50% by weight. . 6. The polymer is a copolymer of ethylene, vinyl acetate, and an acrylate-based and / or methacrylate-based monomer, and has a vinyl acetate content of 10 to 50% by weight and an acrylate-based and / or methacrylate-based monomer content. The adhesive composition for liquid crystal display device according to any one of claims 1 to 4, wherein the ratio is 0.01 to 10% by weight. 7. The polymer is a copolymer of ethylene, vinyl acetate, maleic acid and / or maleic anhydride,
The vinyl acetate content is 10 to 50% by weight, and the content of maleic acid and / or maleic anhydride is 0.01 to 10% by weight, according to any one of claims 1 to 4. An adhesive composition for a liquid crystal display device. 8. A polymer comprising ethylene and an acrylate-based and / or methacrylate-based monomer and maleic acid and / or
Or a copolymer with maleic anhydride, wherein the content of the acrylate compound is 10 to 50% by weight, and the content of maleic acid and / or maleic anhydride is 0.01 to 10% by weight. The adhesive composition for a liquid crystal display device according to any one of claims 1 to 4. 9. The polymer according to claim 1, wherein the polymer is the ionomer resin, the content of methacrylic acid is 1 to 30% by weight, and the degree of ionization by metal ions is 5 to 80%. The adhesive composition for a liquid crystal display device according to item 1.