JP3498157B2 - Pressure sensitive adhesive composition for liquid crystal device and liquid crystal device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition for a liquid crystal element or a liquid crystal display device (hereinafter, sometimes simply referred to as “liquid crystal element”) and the pressure-sensitive adhesive composition. The present invention relates to a manufactured liquid crystal element. More specifically, the present invention is peelable at the time of manufacturing a liquid crystal display device,
The present invention relates to a pressure-sensitive adhesive composition for a liquid crystal element that has excellent durability under high temperature and high humidity conditions, and a liquid crystal element manufactured using the pressure-sensitive adhesive composition.

[0002]

BACKGROUND OF THE INVENTION A liquid crystal element is composed of two substrates having transparent electrodes arranged on the surface in contact with liquid crystal, a liquid crystal material filled between the two substrates, and outer surfaces of the two substrates. Or a laminated plate of a polarizing plate and a retardation plate.

In such a liquid crystal element, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is attached to the surface of a substrate by using a pressure sensitive adhesive. An acrylic resin is often used as a pressure-sensitive adhesive used for attaching such a polarizing plate or a laminated plate of a polarizing plate and a retardation plate to the surface of a substrate.

In recent years, the liquid crystal element has been used in a remarkably wide range of applications such as a display unit of a desk-top electronic computer, a display panel of a personal computer, a liquid crystal display device mounted on a vehicle, and a screen of a television, and thus the application is expanded. Accordingly, the usage environment of liquid crystal elements has become extremely severe. Accordingly, it is desirable that the adhesive strength between the polarizing plate or the laminated plate of the polarizing plate and the retardation plate and the glass is high so as to withstand such use conditions, and that the high adhesive strength does not fluctuate for a long period of time. From this point of view, an acrylic resin adhesive is used.

By the way, in the process of manufacturing a liquid crystal element using such an adhesive, when a problem occurs in bonding the polarizing plate or the laminated plate of the polarizing plate and the retardation plate,
It is necessary to peel off the polarizing plate or the laminated plate of the polarizing plate and the retardation plate, and reattach the polarizing plate or the laminated plate of the polarizing plate and the retardation plate to manufacture a liquid crystal element. That is,
Compared with a polarizing plate or a laminated plate of a polarizing plate and a retardation plate, the liquid crystal cell and the liquid crystal material filled in the cell are extremely expensive, and thus the polarizing plate or the polarizing plate and the retardation plate are Since the liquid crystal material and the cell itself filled with the liquid crystal material often have no problem even if the laminated plate is poorly adhered, reattach the polarizing plate or the laminated plate of the polarizing plate and the retardation plate. If so, good liquid crystal performance is exhibited.

However, since the environment in which the liquid crystal element is used has become considerably severe as described above, the adhesive strength of the adhesive for adhering the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is also extremely high. A polarizing plate or a laminated plate of a polarizing plate and a retardation film, which is pasted with an acrylic resin adhesive that has been conventionally used, has a high adhesive strength, and therefore, a glass substrate is used when peeling. In many cases, it cannot be used as a liquid crystal element because it is damaged or the width of the gap filled with the liquid crystal material changes. Further, even if the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is peeled off, the adhesive remains on the glass substrate, and in fact, a new polarizing plate or the laminated plate of the polarizing plate and the retardation plate is attached. There is a problem that you cannot wear it.

In addition, the adhesive for such a liquid crystal element includes
Considering the current state of use of liquid crystal elements, which is exposed to high-temperature and high-humidity conditions such as when used in vehicle-mounted liquid-crystal elements, adhesives for liquid-crystal elements can be used as polarizing plates even under such high-temperature and high-humidity conditions. Alternatively, the property (durability) that foaming or peeling does not occur in the laminated plate of the polarizing plate and the retardation plate is required.

As described above, the pressure-sensitive adhesive used for sticking the polarizing plate or the laminated plate of the polarizing plate and the retardation plate to the glass substrate of the liquid crystal element can maintain stable adhesive strength for a long period of time. That is, there is a contradictory characteristic that the polarizing plate or the laminated plate of the polarizing plate and the retardation plate can be easily peeled off without damaging the liquid crystal element when peeling.

[0009]

An object of the present invention is to provide a pressure-sensitive adhesive composition which is particularly suitable for adhering a glass substrate and a polarizing plate or a glass substrate and a laminated plate of a polarizing plate and a retardation plate. I am trying.

More specifically, the present invention surely adheres a polarizing plate or a laminated plate of a polarizing plate and a retardation plate to a glass substrate which constitutes a liquid crystal element with appropriate strength, and at the same time, the polarizing plate or polarizing plate is manufactured in a manufacturing process. When it becomes necessary to peel off the laminated plate of the plate and the retardation plate, it can be peeled without damaging the liquid crystal cell such as the glass substrate, and the adhesive remains on the glass substrate. It is an object of the present invention to provide a pressure-sensitive adhesive composition for liquid crystal devices, which is difficult to use.

It is another object of the present invention to provide a liquid crystal device in which a polarizing plate or a laminated plate of a polarizing plate and a retardation film is adhered on a glass substrate with the adhesive composition as described above. .

[0012]

SUMMARY OF THE INVENTION A pressure-sensitive adhesive composition for a liquid crystal device according to the present invention comprises an acrylic polymer , a rosin liquid having a glass transition temperature of 0 ° C. or lower and exhibiting fluidity at 25 ° C.
Resin, terpene liquid resin, petroleum liquid resin, coumaro
Indene liquid resin, styrene liquid resin, phenol
From the group consisting of liquid resin and xylene liquid resin
It is characterized by comprising at least one kind of liquid resin selected and containing the liquid resin in an amount of 2 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer.

In addition, in the liquid crystal device of the present invention, liquid crystal is filled in a gap formed by two substrates in which a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is arranged on the surface of the substrate. In a liquid crystal device, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is provided on the surface of the substrate, an acrylic polymer, a glass transition temperature of 0 ° C. or lower, and a rosin showing fluidity at 25 ° C. Liquid resin, terpene liquid
Resin, petroleum liquid resin, coumarone / indene liquid resin,
Styrene liquid resin, phenol liquid resin and xy
At least one selected from the group consisting of len-based liquid resins
Liquid polymer of the same class , and the acrylic polymer 100
It is characterized in that it is attached by a pressure-sensitive adhesive composition containing the liquid resin in an amount of 2 to 100 parts by weight with respect to parts by weight.

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention has a glass transition temperature of 0 ° C. or lower and room temperature (25 ° C.).
Liquid resin is mixed in. By containing this liquid resin, the adhesive of the present invention requires a substrate and a polarizing plate or a laminated plate of a polarizing plate and a retardation plate in an environment in which a liquid crystal element is actually used. In addition, it can be bonded with sufficient adhesive strength. Moreover, the adhesive strength does not become excessively high due to heating in the liquid crystal element manufacturing process. Therefore, when adhesion failure occurs in the manufacturing process of the liquid crystal element, the polarizing plate or the laminated plate of the polarizing plate and the retardation plate can be easily peeled off from the substrate. Is hard to remain.

Although the pressure-sensitive adhesive of the present invention has the characteristic that it can be peeled off in the manufacturing process of liquid crystal elements as described above, it can be used under severe conditions such as high temperature and high humidity. Even when a liquid crystal element is used, the pressure-sensitive adhesive composition of the present invention exhibits good adhesiveness, and even when used under such conditions, a polarizing plate or a laminate of a polarizing plate and a retardation plate is laminated. Adhesion failure such as swelling or peeling on the plate is unlikely to occur.

A liquid crystal device to which a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is attached with the adhesive composition of the present invention is a laminated body of a transparent substrate and a polarizing plate or a polarizing plate and a retardation plate. The adhesion to the plate is good, and the adhered state of the two is stable for a long period of time. Therefore, the liquid crystal device of the present invention can maintain excellent optical characteristics for a long period of time.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The pressure-sensitive adhesive composition for a liquid crystal element and the liquid crystal element of the present invention will be specifically described.

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
It is composed of an acrylic polymer and a liquid resin having a glass transition temperature of 0 ° C. or lower and having fluidity at 25 ° C. (room temperature). The acrylic polymer is a (co) polymer such as an acrylic monomer such as a (meth) acrylic acid ester or a functional group-containing acrylic monomer.

Examples of the (meth) acrylic acid ester used here include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. , Lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate. It can be used alone or in combination. The acrylic polymer used in the present invention contains the repeating unit derived from the (meth) acrylic acid ester in an amount of usually 50 to 99.5% by weight, preferably 60 to 99% by weight, and more preferably 8%.
It has an amount of 0 to 98% by weight.

Examples of functional group-containing acrylic monomers include acrylic acid, methacrylic acid, β-carboxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, chloro-2- Hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate,
Examples thereof include dimethylaminoethyl (meth) acrylate and glycidyl (meth) acrylate.
It can be used alone or in combination. The acrylic polymer used in the present invention contains the repeating unit derived from the above functional group-containing acrylic monomer in an amount of usually 0.5 to 20% by weight, preferably 1 to 20% by weight.
%, More preferably 2 to 10% by weight. Among the functional group-containing monomers described above, a carboxyl group-containing monomer such as (meth) acrylic acid is particularly preferable.

The acrylic polymer used in the present invention may have a repeating unit derived from a monomer other than the above-mentioned (meth) acrylic acid ester and the functional group-containing acrylic monomer. Examples include repeating units derived from styrenic monomers and repeating units derived from vinylic monomers.

Specific examples of the styrene-based monomer include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene. Alkyl styrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene and iodostyrene; and nitrostyrene, acetylstyrene and methoxystyrene.

Examples of vinyl monomers include vinylpyridine, vinylpyrrolidone, vinylcarbazole, divinylbenzene, vinyl acetate and acrylonitrile; conjugated diene monomers such as butadiene, isoprene and chloroprene; halogens such as vinyl chloride and vinyl bromide. Vinyl halide; vinylidene halide such as vinylidene chloride and the like can be mentioned.

These monomers can be used alone or in combination. The repeating unit derived from the other monomer in the acrylic polymer used in the present invention is usually 0 to 45% by weight, preferably 0.
-20% by weight, particularly preferably 0-10% by weight.

The acrylic polymer used in the present invention is prepared, for example, by adding the above-mentioned monomers to a reaction solvent and replacing the air in the reaction system with an inert gas such as nitrogen gas, and then reacting the mixture if necessary. It can be produced by heating and stirring to cause a polymerization reaction in the presence of an initiator.

As the reaction solvent used here, an organic solvent is used, and specifically, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-hexane, ethyl acetate and butyl acetate. And the like, aliphatic alcohols such as n-propyl alcohol and iso-propyl alcohol, and ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone.

As the reaction initiator, for example, azobisisobutyronitrile, benzoyl peroxide, diester
-tert-Butyl peroxide and cumene hydroperoxide can be used.

The reaction temperature of the above polymerization reaction is usually 50 to
90 ° C, the reaction time is usually 2 to 20 hours, preferably 4
~ 12 hours. In the reaction as described above, the monomer can be added in an amount corresponding to the amount of each repeating unit in the acrylic polymer to be obtained.

The reaction solvent is a total amount of monomers of 100.
It is used in an amount of 50 to 300 parts by weight with respect to parts by weight.
Further, the reaction initiator is usually used in an amount of 0.01 to 10 parts by weight.

By carrying out the reaction as described above, the acrylic polymer used in the present invention can be obtained as a solution or a dispersion liquid in which the reaction solvent contains the (co) polymer in an amount of 25 to 70% by weight. In the present invention, after removing the solvent from this dispersion, the obtained acrylic polymer may be blended with other components. However, in the present invention, it is preferable to mix the acrylic polymer and other components in a state of being dispersed in the reaction solvent without removing the reaction solvent obtained as described above. Generally, the acrylic polymer obtained as described above is stably dispersed in the reaction solvent, and by using such a dispersion as it is, the respective components can be uniformly mixed.

The acrylic polymer used in the present invention is usually 100,000 to 15,000,000, preferably 3
It has a weight average molecular weight of 00000-800000. In addition, you may mix | blend other components, such as an inorganic filler, with this acrylic polymer within the range which does not impair the objective of this invention.

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
It comprises the acrylic polymer and a liquid resin having a glass transition temperature of 0 ° C. or lower and having fluidity at 25 ° C. That is, with only the acrylic polymer as described above,
When the adhesive strength after applying heat becomes too high and the adhesion state of the polarizing plate etc. becomes defective, peel off this polarizing plate etc. and reattach it without damaging the body of the liquid crystal element. I can't. Further, with only the acrylic polymer, the adhesive often remains on the substrate to which the polarizing plate or the like has been attached, so that the replacement of the polarizing plate or the like cannot be performed smoothly.

In the present invention, the adhesive strength of this adhesive can be adjusted to a necessary and sufficient range by blending the above acrylic polymer with a specific liquid resin, and the adhesive is used under severe conditions. However, it was made based on the finding that peeling or swelling does not occur in the polarizing plate or the laminated plate of the polarizing plate and the retardation plate.

This liquid resin has fluidity at room temperature (that is, 25 ° C.), and the viscosity of this solution at 25 ° C. when diluted to 80% with toluene is usually 10 ⁴ centipoise or less, preferably Is less than 10 ³ centipoise. The liquid resin has a glass transition temperature of 0 ° C. or lower, and further has a glass transition temperature of −80 to −10.
Resins in the range of ° C are preferred. By using a liquid resin having a glass transition temperature within the above range, it is possible to obtain necessary and sufficient adhesive strength at normal temperature, and even when heated to a high temperature, the adhesive strength does not become excessively high. . Resins that are solid at room temperature and have a glass transition temperature above 0 ° C. (for example, a glass transition temperature of 36
(° C α-methylstyrene resin), the initial adhesive strength and the adhesive strength after heating become too high, and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is peeled off from the glass substrate of the liquid crystal element. At this time, the liquid crystal element is likely to be damaged, and the adhesive may remain on the liquid crystal element substrate after heating. As described above, a liquid resin having fluidity at room temperature and a glass transition temperature of 0 ° C. or lower generally has a pour point within a range of the glass transition temperature to 25 ° C.

Further, the liquid resin is preferably one which can form a transparent mixture with the above-mentioned acrylic polymer. That is, the liquid resin of the present invention usually has compatibility with an acrylic polymer that a mixture obtained by mixing 100 parts by weight of the acrylic polymer in an amount of 2 to 100 parts by weight becomes transparent. . This is to ensure the optical characteristics of the liquid crystal element.

Examples of resins having such characteristics include rosin-based liquid resins, terpene-based liquid resins and synthetic liquid resins. Specific examples of the rosin-based liquid resin include rosin ester and modified rosin alcohol.

Specific examples of the terpene-based liquid resin include terpene resin and modified terpene resin. Furthermore, specific examples of the synthetic liquid resin include petroleum-based liquid resin, coumarone-indene liquid resin, styrene-based liquid resin, phenol-based liquid resin, and xylene-based liquid resin.

The liquid resin used in the present invention has a molecular weight of
Since the glass transition temperature and the viscosity at 25 ° C. vary depending on the structure and the like, the number average molecular weight of the liquid resin used in the present invention is usually in the range of 150 to 4000, and in many cases in the range of 150 to 1000.

Among the above liquid resins, particularly in the present invention, xylene liquid resin, styrene liquid resin and rosin liquid resin can be particularly preferably used. By using the liquid resin as described above, the pressure-sensitive adhesive composition of the present invention has a substrate, particularly a glass substrate, and a polarizing plate or a laminated plate of a polarizing plate and a retardation plate, which are provided in JIS described later. 200-2000g / measured by the specified method
Can be bonded with an adhesive strength of about 25 mm. Further, the pressure-sensitive adhesive composition of the present invention is adhesively processed to a polarizing plate or a laminated plate of a polarizing plate and a retardation plate, and the polarizing plate or the laminated plate of the polarizing plate and a retardation plate is applied to the surface of a glass substrate. Even if it is peeled off after adhering to, the adhesive component is removed together with the polarizing plate or the laminated plate of the polarizing plate and the retardation plate without remaining on the glass substrate surface.

The pressure-sensitive adhesive composition for liquid crystal element of the present invention comprises
The liquid resin is contained in an amount of 2 to 100 parts by weight, preferably 5 to 50 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of the acrylic polymer.
If the amount of the liquid resin added exceeds 100 parts by weight, the adhesive strength may be too low and peeling may occur. Further, if the amount of the liquid resin added is less than 2 parts by weight, the desired releasability at the time of producing the liquid crystal element and the durability under high temperature and high humidity conditions, which is the object of the present invention, are not exhibited.

The pressure-sensitive adhesive composition for liquid crystal element of the present invention comprises
Although the above-mentioned acrylic polymer and the above-mentioned specific liquid resin are contained as essential components, other components may be further contained. Examples of other components that can be added to the pressure-sensitive adhesive composition for liquid crystal devices of the present invention include solid tackifiers, crosslinking agents and dyes. As the above-mentioned other components, already known components can be blended alone or in combination.

In the liquid crystal device of the present invention, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is adhered to a substrate with the above pressure-sensitive adhesive composition for liquid crystal devices. FIG. 1 schematically shows a cross section of the liquid crystal element of the present invention.

As shown in FIG. 1, the liquid crystal element 1 of the present invention.
Has two substrates 2 and 2 and a liquid crystal 3 filled in a gap formed by the two substrates 2 and 2. This substrate is made of glass or transparent synthetic resin.
The thickness of this substrate is usually 0.01 to 2.0 mm. In the present invention, a glass substrate is particularly preferable as this substrate.

Transparent electrodes 4 and 4 are formed on the surfaces of the two substrates 2 and 2 which are in contact with the liquid crystal material 3. The transparent electrode is usually made of ITO or the like. The thickness of this transparent electrode is typically 100-2000 Angstroms.
A liquid crystal alignment film (not shown) may be further formed on the transparent electrodes 4, 4. This liquid crystal alignment film can be formed by rubbing a polyimide resin.

The substrate having the transparent electrode and the liquid crystal alignment film formed on one surface as described above is arranged so that the transparent electrodes 4 face each other and form a constant gap. Transparent electrode 4,
The fixed gap formed between the four is usually formed by using the spacer 5. As the spacer 5, for example, inorganic particles, inorganic fibers, resin particles, or a resin film formed in a predetermined pattern (for example, comb shape) can be used. The spacer may also serve as the liquid crystal alignment film.

The width of the gap thus formed is usually 1
10 to 10 μm. The two transparent substrates arranged with a gap as described above are usually bonded by sealing the periphery 6 with a sealing material. As the sealing material 6, an epoxy resin, a silicone resin, or the like can be used.

The liquid crystal 3 is filled in the gap formed as described above. As the liquid crystal 3 filled here, a Schiff base liquid crystal compound, an azoxy liquid crystal compound,
Examples thereof include benzoic acid ester liquid crystal compounds, cyclohexylcarboxylic acid ester liquid crystal compounds, phenyl liquid crystal compounds, terphenol liquid crystal compounds, cyclohexyl liquid crystal compounds, and pyrimidine liquid crystal compounds. These liquid crystal compounds can be used alone or in combination.

The liquid crystal element has the above-mentioned structure. In the liquid crystal element of the present invention, a polarizing plate or a phase difference with the polarizing plate is provided on the outer surface of the substrate by using a specific adhesive composition. Laminated boards 7, 7'with boards are attached.

The polarizing plate used here is, for example, a polyester film, a polyvinyl alcohol resin film,
It can be manufactured by dyeing a resin film such as a polyvinyl butyral resin film with iodine or a dichroic dye, stretching it uniaxially, and laminating a protective film such as a triacetate film from both sides.

The polarizing plate or the laminated plates 7 and 7'of the polarizing plate and the retardation plate are attached to the surface of the substrate 2 as follows.
First, a laminated plate 7 or 7'of a polarizing plate or a polarizing plate and a retardation plate
A polarizing plate or a laminated plate of the polarizing plate and the retardation plate is adhered to the surface of the polarizing plate or the laminated plate of the polarizing plate and the retardation plate by using the pressure-sensitive adhesive composition for liquid crystal element described above. Then, the adhesive layers 8 and 8 are formed. The thickness of the adhesive layers 8, 8 thus formed is usually 10 to 50 μm, preferably 15 to 40 μm. By forming the adhesive layer with the above thickness, the substrate and the polarizing plate, or the substrate and the laminated plate of the polarizing plate and the retardation plate can be bonded with necessary and sufficient adhesive strength. At the same time, the adhesive layers 8 and 8 are transparent, and the optical characteristics of the liquid crystal element are not deteriorated by the adhesive layers.

The polarizing plate on which the adhesive layer 8 is thus formed or the laminated plate of the polarizing plate and the retardation plate is pressure-bonded to the outer surface of the substrate 2. If necessary, heating can be performed during this pressure bonding. By pressure-bonding in this manner, a pressure-sensitive adhesive composition for liquid crystal elements, which is composed of a liquid resin having a glass transition temperature of 0 ° C. or less and an acrylic polymer, a substrate surface and a polarizing plate surface (or a polarizing plate and a retardation plate). Adhesive strength with suitable strength is developed between the laminated sheet and In addition,
The time required for this pressure bonding is, for example, about 10 to 30 minutes at 50 ° C. and 5 atmospheric pressure.

As described above, by using the pressure-sensitive adhesive composition for liquid crystal elements of the present invention, the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is adhered to the surface of the substrate with a suitable adhesive force. It becomes difficult for a gap to occur between the substrate and the polarizing plate, or between the substrate and the laminated plate of the polarizing plate and the retardation plate. Further, even if the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is peeled from the glass substrate, the adhesive does not remain on the glass substrate surface, and the glass substrate or the liquid crystal cell is damaged during the peeling. There is nothing to do.

Further, in the liquid crystal element of the present invention, the substrate and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate are stably bonded for a long period of time, so that the substrate and the polarizing plate or the substrate and the polarizing plate are adhered to each other. It is possible to effectively prevent the performance of the liquid crystal element from being deteriorated due to poor adhesion between the retardation plate and the laminated plate.

[0054]

The pressure-sensitive adhesive composition for a liquid crystal element of the present invention contains the above-mentioned specific liquid resin, and by using this adhesive composition, the substrate and the polarizing plate or the polarizing plate can be aligned with each other. The retardation plate and the laminated plate can be bonded together with a bonding strength necessary and sufficient for use in an environment where the liquid crystal element is actually used.

In addition, if this adhesive strength causes a problem in the adhesion in the liquid crystal element manufacturing process, the adhesive can be peeled off without leaving the adhesive component on the substrate, and further the glass substrate can be peeled off. Alternatively, the liquid crystal cell is rarely damaged.

As described above, although the pressure-sensitive adhesive for liquid crystal elements of the present invention can be peeled off in the manufacturing process, swelling or peeling occurs when the liquid crystal element is used under high temperature and high humidity conditions. It is difficult to do so, and by using this adhesive, the liquid crystal element can be used for a long time under severe conditions.

In addition, the liquid crystal element of the present invention has good adhesion between the glass substrate and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate, and the adhesion state of the both is stable for a long period of time. Therefore, the liquid crystal device of the present invention can maintain excellent optical characteristics for a long time.

[0058]

The present invention will be described in more detail below with reference to examples of the present invention, but the present invention should not be construed as limited by these examples.

[0059]

Example 1 25 parts by weight of 2-ethylhexyl acrylate, 43 parts by weight of n-butyl acrylate, 3 parts by weight of styrene, 20 parts by weight of ethyl acrylate, 7 parts by weight of acrylic acid, 2 parts by weight of 2-hydroxyethyl acrylate, acetic acid. 100 parts by weight of ethyl and 0.2 parts by weight of azobisisobutyronitrile were placed in a reactor, the air in the reactor was replaced with nitrogen gas, and the reaction solution was stirred at 63 ° C. in a nitrogen atmosphere. The temperature was raised to 2, and the reaction was performed for 2 hours.

Separately, a solution was prepared by dissolving 0.05 parts by weight of azobisisobutyronitrile in 10 parts by weight of ethyl acetate. 10 parts by weight of the thus-prepared solution of azobisisobutyronitrile in ethyl acetate was added dropwise to the reaction solution heated to 63 ° C. over 2 hours.

Further, this reaction solution was heated to 72 ° C., and 10 parts by weight of an ethyl acetate solution of azobisisobutyronitrile prepared in the same manner as above was added dropwise over 4 hours.

220 parts by weight of a solution of an acrylic polymer in ethyl acetate was obtained by performing the above operation and polymerizing for a total of 8 hours. The concentration of the acrylic polymer in this ethyl acetate solution is 45% by weight.

220 parts by weight of the above reaction liquid (corresponding to 100 parts by weight of the acrylic polymer) is a synthetic liquid resin, a styrene liquid resin (styrene resin, glass transition temperature: -4).
Viscosity of 2%, 80% solution (solvent: toluene) at 25 ° C: 43 centipoise, number average molecular weight: 250, trade name: Picolastic A5, manufactured by Rika Hercules Co., Ltd.
15 parts by weight and a polyisocyanate compound (trade name: Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent 2
Parts by weight and well stirred to obtain an adhesive composition of the present invention. When the mixture of the liquid styrene resin and the acrylic polymer was dried, it was transparent.

The adhesive composition thus obtained was coated on a polyester release film and then dried (dry coating thickness of the adhesive composition: 25 μm). Then, the adhesive composition applied on the release film was coated with a thickness of
After transfer onto a 20 mm polarizing plate and aging for 7 days at a temperature of 23 ° C. and a humidity of 65%, the polarizing plate and the glass substrate are held at a temperature of 50 ° C. and a pressure of 5 kg / cm ² for 20 minutes. Glued.

The adhesive force between the polarizing plate and the glass substrate thus bonded is determined according to JIS-Z-0237 and JIS-Z-0238.
The initial adhesive strength (adhesive strength after leaving at 23 ° C. for 1 hour) was measured according to. Furthermore, the sample prepared in the same manner was left at 80 ° C. for 10 hours and then cooled to 23 ° C.,
The adhesive strength after standing for 1 hour at this temperature was measured. The smaller the difference in adhesive strength between the two, the better the removability, and the smaller the difference in adhesive strength is. Furthermore, when measuring the above-mentioned adhesive strength, the residual property (adhesive residue) of the adhesive on the surface of the glass substrate was visually observed and evaluated.

Also, 20 samples prepared in the same manner were used.
Cut into 30 cm ² and adhere under the above conditions, 100 ℃
× 500 hours and 60 ° C 90% RH × 500 hours After the standing condition, the occurrence of foaming and peeling was visually observed and evaluated.

The results are shown in Table 1. The liquid crystal device in which the polarizing plate prepared as described above was attached to the surface showed good characteristics.

[0068]

Example 2 In Example 1, instead of the styrene liquid resin, a xylene liquid resin (modified xylene formaldehyde resin, glass transition temperature: -31 ° C., viscosity of 80% solution (solvent: toluene) at 25 ° C .: 73 centipoise, number average molecular weight: 400, trade name: Nikanol L, manufactured by Mitsubishi Gas Chemical Co., Inc. 10 parts by weight was used in the same manner as above to obtain an adhesive composition of the present invention. When the mixture of the liquid xylene resin and the acrylic polymer was dried, it was transparent.

Using the adhesive composition produced as described above, its characteristics were evaluated in the same manner as in Example 1.

[0070]

Example 3 In Example 1, instead of the liquid styrene resin, a rosin-based liquid resin (rosin alcohol resin, glass transition temperature: -20 ° C, viscosity of 80% solution (solvent: toluene) at 25 ° C: 116 centipoise. , Number average molecular weight: 275, trade name: abitol, manufactured by Rika Hercules Co., Ltd.), and an adhesive composition of the present invention was obtained in the same manner except that 15 parts by weight was used. When the mixture of the rosin ester and the acrylic polymer was dried, it was transparent.

The results are shown in Table 1. Using the adhesive composition produced as described above, its characteristics were evaluated in the same manner as in Example 1.

The results are shown in Table 1.

[0073]

Comparative Example 1 An adhesive composition was obtained in the same manner as in Example 1 except that the liquid styrene resin was not used and the amount of the above-mentioned polyisocyanate compound as a crosslinking agent was changed to 2 parts by weight. .

Using the adhesive composition produced as described above, its characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0075]

[Comparative Example 2] In Example 1, instead of the liquid styrene resin, a styrene resin (α-methylstyrene resin, glass transition temperature: 36 ° C, solid at 25 ° C, which is a synthetic solid resin, has a fluidity. No, number average molecular weight: 44
No. 0, trade name: Crystalrex 3085, 10 parts by weight of Rika Hercules Co., Ltd. was used to obtain an adhesive composition in the same manner.

[0076]

[Table 1]

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a liquid crystal element of the present invention.

[Explanation of symbols]

1 ... Liquid crystal element 2 ... Substrate 3 ... Liquid crystal material 4 ... Transparent electrode 5 ... Spacer 6 ... Sealing material 7, 7 '... Polarizing plate Laminated plate with phase difference plate 8 ... Adhesive layer

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Claims (6)

(57) [Claims] Shows a 1. A acrylic polymer, the glass transition temperature is at 0 ℃ or less, and the fluidity at 25 ° C.,
Rosin-based liquid resin, terpene-based liquid resin, petroleum-based liquid resin
Fat, coumarone / indene liquid resin, styrene liquid resin
Oils, phenolic liquid resins and xylene liquid resins
Consisting of at least one liquid resin selected from the group consisting of
A pressure-sensitive adhesive composition for a liquid crystal device, which comprises the liquid resin in an amount of 2 to 100 parts by weight. 2. The pressure-sensitive adhesive composition for a liquid crystal device according to claim 1, wherein the liquid resin has a viscosity of 10 ⁴ centipoise or less at 25 ° C. when it is a toluene solution having a solid content of 80%. object. 3. The number average molecular weight of the liquid resin is 150.
To 4,000 in range.
Item or the pressure-sensitive adhesive composition for liquid crystal device according to item 2. 4. The acrylic polymer comprises 50 to 99.5% by weight of alkyl (meth) acrylate, 0.5 to 20% by weight of a monomer having a functional group, and 0 to 45% by weight of another copolymerizable monomer. The pressure-sensitive adhesive composition for liquid crystal elements according to claim 1, which is a copolymer of 5. The liquid resin according to claim 1 or 4, wherein the liquid resin is transparently mixed in an amount within a range of 2 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer. A pressure-sensitive adhesive composition for a liquid crystal device as described above. 6. A liquid crystal device in which liquid crystal is filled in a gap formed by two substrates in which a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is arranged on the surface of the substrate. A rosin-based liquid , on the surface of which a polarizing plate or a laminated plate of a polarizing plate and a retardation plate, an acrylic polymer, a glass transition temperature of 0 ° C. or lower, and fluidity at 25 ° C.
Resin, terpene liquid resin, petroleum liquid resin, coumaro
Indene liquid resin, styrene liquid resin, phenol
From the group consisting of liquid resin and xylene liquid resin
It is composed of at least one kind of liquid resin selected , and is stuck by a pressure-sensitive adhesive composition containing the liquid resin in an amount of 2 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer. Liquid crystal device characterized by.