JP3533446B2 - Pressure sensitive adhesive composition for liquid crystal device and liquid crystal device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element or a liquid crystal display device (hereinafter collectively referred to simply as "liquid crystal element").
And a liquid crystal element manufactured using the pressure-sensitive adhesive composition. More specifically, the present invention uses a pressure-sensitive adhesive composition for a liquid crystal element, which can be peeled off during the production of a liquid crystal display device and has excellent durability under high temperature and high humidity conditions, and this pressure-sensitive adhesive composition. The present invention relates to a manufactured liquid crystal element.

[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.

Considering the current state of use of liquid crystal elements, in which such an adhesive agent for a liquid crystal element is exposed to high temperature and high humidity conditions such as when it is used for a vehicle-mounted liquid crystal element, an adhesive agent for a liquid crystal element is The property (durability) that foaming or peeling does not occur in the polarizing plate or the laminated plate of the polarizing plate and the retardation plate even when used under such high temperature and high humidity conditions 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 of the present invention comprises an acrylic polymer and a silane compound represented by the following formula and having an alkoxy group having a β-ketoester structure. It is characterized in that the silane compound is contained in an amount of 0.001 to 5 parts by weight with respect to 100 parts by weight of the base polymer.

[Chemical 3] However, R represents a hydrocarbon group having 1 to 6 carbon atoms, and n
Represents an integer of 0 to 20, a is an integer of 1 to 3 , b is 1 to 3
, C is 0 or 1, and a + b + c = 4 .

Further, 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 the liquid crystal element, on the surface of the substrate, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate has an acrylic polymer, a β-ketoester structure, and a silane compound represented by the following formula having an alkoxy group. And a pressure-sensitive adhesive composition containing the silane compound in an amount of 0.001 to 5 parts by weight based on 100 parts by weight of the acrylic polymer.

[Chemical 4] However, R represents a hydrocarbon group having 1 to 6 carbon atoms, and n
Represents an integer of 0 to 20, a is an integer of 1 to 3 , b is 1 to 3
, C is 0 or 1, and a + b + c = 4 .

The pressure-sensitive adhesive composition for liquid crystal devices of the present invention contains a specific silane compound having a β-ketoester structure and an alkoxy group. By containing this silane compound, The adhesive composition of the invention is
The substrate and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate can be bonded with necessary and sufficient adhesive strength required in the environment where the liquid crystal element is actually used. 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 from the glass substrate from the substrate. It is difficult for the adhesive to remain.

The pressure-sensitive adhesive composition of the present invention has the characteristic that it can be peeled off in the manufacturing process of a liquid crystal element as described above, but is harsh under high temperature and high humidity conditions. Even when the liquid crystal element is used under the conditions, it exhibits good adhesiveness, and even when used under such conditions, the polarizing plate or the laminated plate of the polarizing plate and the retardation plate has no swelling or peeling. Poor adhesion 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 contains an acrylic polymer, which is the main component of the adhesive, and a silane compound having a β-ketoester structure and having an alkoxy group.

The acrylic polymer has a pressure-sensitive adhesive property, and is usually a (co) polymer formed from an acrylic monomer such as (meth) acrylic acid ester or a functional group-containing acrylic monomer. used.

Examples of the (meth) acrylic acid ester used here include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 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 has the repeating unit derived from the (meth) acrylic acid ester in an amount of usually 60 to 99% by weight, preferably 80 to 98% by weight.

Examples of the functional group-containing acrylic monomer include acrylic acid, methacrylic acid, β-carboxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and chloro-2- Hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate,
Dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N-
Examples thereof include methylol (meth) acrylamide and N-ethylol (meth) acrylamide. 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 1 to 20% by weight, preferably 2 to 10% by weight.
Have in quantity.

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 above-mentioned other monomer in the acrylic polymer used in the present invention is usually 0 to 20% by weight, preferably 0.
It is contained in an amount of 10 to 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 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.

When a reaction initiator is used, for example, azobisisobutyronitrile, benzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide and the like 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 contains the acrylic polymer and a silane compound having a β-ketoester structure and having an alkoxy group.
The silane compound used in the present invention is required to have a β-ketoester structure, and this silane compound further has an alkoxy group as a functional group.

The group having a β-ketoester structure can be represented by the following formula [I].

[0035]

[Chemical 1]

However, in the above formula [I], R represents a hydrocarbon group having 1 to 6 carbon atoms, and in the present invention, it is preferable that R is a methyl group. That is, the silane compound used in the present invention is an acetoacetyl group (CH _3-
It is preferred to have the CO-CH ₂ -CO-). The group having the β-ketoester structure may be directly bonded to a silicon atom, or may be bonded via an alkylene group [-(CH ₂ ) _n- ; n is usually an integer of 1 to 20] and the like. May be.

The alkoxy group which is a functional group introduced into a silicon atom in the present invention is usually a methoxy group or an ethoxy group. Per molecule of silane compound,
The number of groups having a β-ketoester structure represented by the above formula [I] is usually 1 to 3. The number of alkoxy groups is 1 to 3 per molecule of the silane compound.

Specific examples of the above-mentioned silane compound having a group having a β-ketoester structure and an alkoxy group include the compounds described below.

[0039]

[Chemical 5]

By using the above-mentioned β-ketoester structure and a silane compound having an alkoxy group as a functional group, the pressure-sensitive adhesive composition of the present invention can be used as a substrate, particularly a glass substrate, and a polarizing plate or a polarizing plate. The phase difference plate and the laminated plate were measured by the method specified in JIS described later to be 200
It can be bonded with an adhesive strength of about 2000 g / 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 glass substrate, the adhesive component does not remain on the glass substrate surface and is removed from the glass substrate surface together with the polarizing plate or the laminate of the polarizing plate and the retardation plate.

The pressure-sensitive adhesive composition for liquid crystal element of the present invention comprises
It is necessary to contain the silane compound in an amount of 0.001 to 5 parts by weight, and more preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the acrylic polymer. To do. When the amount of the silane compound exceeds the above range, the initial adhesive strength is lowered, and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is swollen or peeled off under the environment where the liquid crystal element is used. Further, if it is less than the above range, the adhesive strength after heating becomes too high, causing a defect in the manufacturing process and peeling the polarizing plate or the laminated plate of the polarizing plate and the retardation plate to damage the liquid crystal cell. Or, the non-stick residue on the substrate surface easily occurs. Alternatively, the adhesive residue on the substrate surface is likely to occur. Further, peeling is more likely to occur during moist heat.

In the pressure-sensitive adhesive composition for a liquid crystal device of the present invention, since the silane compound and the acrylic polymer interact with each other, the acrylic polymer and the silane compound are usually packaged separately, Stored and transported. Immediately before use, both are mixed and used in an amount within the above range.

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
Although the above-mentioned acrylic polymer and silane compound are contained as essential components, other components may be further contained if necessary.

Examples of other components that can be added to the pressure-sensitive adhesive composition for liquid crystal devices of the present invention include tackifiers, plasticizers, crosslinking agents and dyes.
As the above-mentioned other components, already known components can be blended alone or in combination.

In particular, the pressure-sensitive adhesive composition for liquid crystal elements of the present invention preferably contains a crosslinking agent. Examples of the cross-linking agent used in the present invention include isocyanate compounds, epoxy compounds, amine compounds, metal chelate compounds and aziridine compounds.

Among the crosslinking agents, examples of isocyanate compounds include tolylene diisocyanate, hydrogenated tolylene diisocyanate, tolylene diisocyanate adduct of trimethylol propane, xylylene diisocyanate adduct of trimethylol propane, triphenylene methane triisocyanate, isophorone. Mention may be made of diisocyanates and their ketoxime block products or phenol block products.

Examples of epoxy compounds include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexane. Diol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diglycidyl amine, N, N, N ', N'-tetraglycidyl-m-xylenediamine and 1,3-bis (N, N'
-Diglycidylaminomethyl) cyclohexane can be mentioned.

Further, examples of the amine compound include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resin and melamine resin.

Furthermore, examples of the metal chelate compound include compounds in which polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium are coordinated with acetylacetone, Examples thereof include compounds in which the polyvalent metal is coordinated with ethyl acetoacetate.

Further, examples of the aziridine compound include N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxamide) and N, N'-toluene-2,4-bis (1-aziridinecarboxamide). , Triethylenemelamine, bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide), tri Mention may be made of methylolpropane-tri-β-aziridinylpropionate and tetramethylolmethane-tri-β-aziridinylpropionate.

Such a crosslinking agent is usually used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the resin component in the composition of the present invention.
It is used in an amount of parts by weight, preferably 0.05-5 parts by weight. Since these cross-linking agents have reactivity with the pressure-sensitive adhesive composition for liquid crystal elements of the present invention, they are packaged separately,
Used just before mixing.

Such cross-linking agents can be used alone or in combination. In the liquid crystal element of the present invention,
A polarizing plate or a laminated plate of a polarizing plate and a retardation plate is adhered on a substrate using the above pressure-sensitive adhesive composition for liquid crystal elements.

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, 4 are formed on the surfaces of the two substrates 2, 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 constant gap formed between the four is usually formed using a 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 constitution, and the liquid crystal element of the present invention uses a specific adhesive composition on the outer surface of the above-mentioned substrate to form a polarizing plate or a phase difference with the polarizing plate. 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 two-color dye and stretching it in a uniaxial direction.

The retardation plate is a film having birefringence and is perpendicular to the light transmitted through the retardation plate.
By causing a difference in the refractive index of the direction, is a film that gives a phase difference to light rays orthogonal to each other after passing through the retardation plate, usually formed of cellulose resin, polyvinyl alcohol resin, polycarbonate resin, cyclic olefin resin, or the like,
Usually, the retardation value is in the range of 135 to 700 nm, and the film is uniaxially stretched so that the variation of the retardation value in the entire film is 15 nm or less.

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, the pressure-sensitive adhesive composition for a liquid crystal element, which comprises a silane compound and an acrylic polymer, and the substrate surface and the polarizing plate surface (or the laminated plate surface comprising the polarizing plate and the retardation plate) During that time, a suitable strength of adhesive force is developed. The time required for this pressure bonding is, for example, about 10 to 30 minutes at 50 ° C. and 5 atmospheres.

By using the pressure-sensitive adhesive composition for a liquid crystal element of the present invention in this manner, 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 adhered 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.

[0065]

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention contains an acrylic polymer as an adhesive main component and a silane compound having a β-ketoester structure and an alkoxy group. By using this adhesive, the substrate and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate are bonded with a necessary and sufficient adhesive strength for use in an environment where the liquid crystal element is actually used. be able to.

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

As described above, the pressure-sensitive adhesive composition for a liquid crystal element of the present invention is swellable or peeled off when the liquid crystal element is used under high temperature and high humidity conditions, although it is peelable in the manufacturing process. Is less likely to occur, and by using this adhesive, the liquid crystal element can be used for a long time under severe conditions.

Further, 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 both is stable for a long period of time. Therefore, in the liquid crystal device of the present invention, excellent optical characteristics are maintained for a long period of time.

[0069]

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.

[0070]

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, 10 parts by weight of ethyl acetate was added with 0.05 of azobisisobutyronitrile.
A solution in which part by weight was dissolved was prepared. 10 parts by weight of the solution of azobisisobutyronitrile thus prepared was added to 63 parts of
It was added dropwise to the reaction solution heated to 0 ° C over 2 hours.

Further, the temperature of this reaction solution was raised to 72 ° C., and 10 parts by weight of a solution of azobisisobutyronitrile prepared in the same manner as above was added dropwise over 4 hours. 220 parts by weight of an ethyl acetate solution of an acrylic polymer was obtained by operating as described above and polymerizing for a total of 8 hours.
The concentration of the acrylic polymer in this ethyl acetate solution is 45% by weight.

To 220 parts by weight of the above reaction solution (corresponding to 100 parts by weight of acrylic polymer), 0.1 part by weight of a silane compound represented by the following formula [II] and a polyisocyanate compound (trade name: Coronate) as a crosslinking agent L, 2 parts by weight of Nippon Polyurethane Co., Ltd.) and well stirred to obtain an adhesive composition of the present invention.

[0073]

[Chemical 3]

The adhesive composition obtained as described above was applied to a polyester release film and dried (adhesive composition dry coating thickness 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.

Regarding the adhesive force between the polarizing plate and the glass substrate thus bonded, JIS-Z-0237 and JIS-Z-
According to 0238, the initial adhesive strength (adhesive strength after leaving at 23 ° C. for 1 hour) was measured. Furthermore, the sample prepared in the same manner was left at 80 ° C. for 10 hours, then allowed to cool to 23 ° C., and left at this temperature for 1 hour, and the adhesive strength was measured. The lower the adhesive strength between the two, the better the peelability. 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.

[0078]

Example 2 An adhesive composition was obtained in the same manner as in Example 1 except that a silane compound represented by the following formula [III] was used instead of the silane compound represented by the formula [II].

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

[0080]

[Chemical 4]

The results are shown in Table 1.

[0082]

Comparative Example 1 An adhesive composition was obtained in the same manner as in Example 1 except that the silane compound represented by the formula [II] was not used.

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.

[0084]

COMPARATIVE EXAMPLE 2 The procedure of Example 1 was repeated except that the silane compound represented by the formula [II] was not used and 0.2 part by weight of the silane compound represented by the following formula [IV] was used. An adhesive composition was obtained.

[0085]

[Chemical 5]

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.

[0087]

Comparative Example 3 Adhesion was the same as in Example 1 except that the silane compound represented by the formula [II] was not used and 0.5 part by weight of the silane compound represented by the following formula [V] was used. An agent composition was obtained.

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.

[0089]

[Chemical 6]

[0090]

[Table 1]

[Brief description of drawings]

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

[Simple 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

Claims (4)

(57) [Claims] 1. An acrylic polymer and a silane compound having a β-ketoester structure and having an alkoxy group and represented by the following formula:
A pressure-sensitive adhesive composition for liquid crystal devices, characterized in that the silane compound is contained in an amount of 0.001 to 5 parts by weight based on 0 parts by weight; (However, R represents a hydrocarbon group having 1 to 6 carbon atoms,
n represents an integer of 0 to 20, a is an integer of 1 to 3, and b is 1 to
3 integers, c is 0 or 1, and a + b + c = 4 der
It ). 2. The pressure-sensitive adhesive composition for a liquid crystal device according to claim 1, wherein the β-ketoester structure of the silane compound is an acetoacetyl group. 3. A copolymer of the acrylic polymer with 60 to 99 parts by weight of alkyl (meth) acrylate, 1 to 20 parts by weight of a monomer having a functional group, and 0 to 20 parts by weight of another copolymerizable monomer. The pressure-sensitive adhesive composition for a liquid crystal element according to claim 1, wherein 4. A liquid crystal element in which a 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. On the surface, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is composed of an acrylic polymer and a silane compound represented by the following formula having an alkoxy group having a β-ketoester structure, A liquid crystal device, characterized in that it is pasted with a pressure-sensitive adhesive composition containing the silane compound in an amount of 0.001 to 5 parts by weight with respect to 100 parts by weight of the polymer; (However, R represents a hydrocarbon group having 1 to 6 carbon atoms,
n represents an integer of 0 to 20, a is an integer of 1 to 3, and b is 1 to
3 integers, c is 0 or 1, and a + b + c = 4 der
It ).