JPH07331206A - Pressure-sensitive adhesive composition for liquid crystal element and liquid crystal element - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive adhesive composition for a liquid crystal element capable of bonding a substrate to a polarizing plate, etc., with necessary and sufficient adhesive force, and also capable of releasing such polarizing plate, etc., from the substrate without damaging the liquid crystal cell and without leaving the adhesive on the substrate even in case the polarizing plate, etc., having been bonded to the substrate get out of order during the production process for a liquid crystal element. CONSTITUTION:This adhesive composition comprises 100 pts.wt. of an acrylic polymer and 0.001-4 pts.wt. of a polymer-type silane coupling agent having affinity for the acrylic polymer and bearing respective functional groups for inorganic and organic materials with the main chain consisting of siloxane skeleton. The other objective liquid crystal element is obtained by applying a polarizing plate, etc., on the substrate through this adhesive composition.

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 has been pasted with an adhesive made of an acrylic resin, which has been conventionally used, has a high adhesive strength, and therefore has a glass substrate at the time of peeling. Is damaged,
The gap width in which the liquid crystal material is filled fluctuates and cannot be used as a liquid crystal element in many cases. 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.

Further, considering the current state of use in which the liquid crystal element is exposed to high temperature and high humidity conditions such as when it is used in a vehicle-mounted liquid crystal element, the adhesive for the liquid crystal element can be used under such high temperature and high humidity conditions. Even in use, the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is required to have the property (durability) that foaming or peeling does not occur.

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 the laminated plate of the plate and the retardation plate from the glass substrate, the laminated plate can be peeled without damaging the liquid crystal cell such as the glass substrate, and the adhesive on the glass substrate It is an object of the present invention to provide a pressure-sensitive adhesive composition for a liquid crystal element, in which the residual is less likely to remain.

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 plate is adhered on a substrate with the above adhesive composition.

[0012]

SUMMARY OF THE INVENTION A pressure-sensitive adhesive composition for a liquid crystal device according to the present invention is a polymer type silane having an acrylic polymer, a functional group for an inorganic substance and a functional group for an organic substance, and a main chain formed of a siloxane skeleton. A coupling agent, and the polymer type silane coupling agent is added to 0.00 parts by weight with respect to 100 parts by weight of the acrylic polymer.
It is characterized in that it is contained in an amount of 1 to 4 parts by weight.

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 a liquid crystal element, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate has an acrylic polymer and a functional group for an inorganic substance and a functional group for an organic substance on the surface of the substrate, and the main chain is formed of a siloxane skeleton. And a polymer-type silane coupling agent, and a pressure-sensitive adhesive composition containing the polymer-type silane coupling agent in an amount of 0.001 to 4 parts by weight based on 100 parts by weight of the acrylic polymer. It is characterized by being attached by.

The pressure-sensitive adhesive composition for liquid crystal devices of the present invention contains a specific polymer type silane coupling agent, and by containing this coupling agent, the adhesive composition of the present invention is The substrate and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate can be bonded together with the 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. Adhesion such as swelling or peeling to the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is shown even if the liquid crystal element is used under the conditions, even if the liquid crystal element is used under such conditions. Less likely to cause defects.

Further, JP-A-57-195208 discloses an invention of a pressure-sensitive adhesive type polarizing plate having a layer composed of a mixture containing an organosilicon monomer having a functional group.

Here, the silicon monomer having a functional group has an unsaturated group such as a vinyl group, an allyl group or an acryloxy group or an amino group, a glycidyl group or a cyclic glycidyl group in one molecule, In addition, hydrogen atom, halogen atom,
It is described as having an alkoxy group such as a hydroxy group, a methoxy group and an ethoxy group, and having two or more different functional groups in the molecule. The pressure-sensitive adhesive composition for liquid crystal elements of the present invention uses a polymer type silane coupling agent whose main chain is formed of a polysiloxane skeleton, has excellent removability, and does not have such a constitution. The composition using is not good in removability as shown in Comparative Example 2 below.

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.

[0019]

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 specific polymer type silane coupling agent. The acrylic polymer has pressure-sensitive adhesiveness, and a (co) polymer formed from an acrylic monomer such as (meth) acrylic acid ester or a functional group-containing acrylic monomer is usually used. .

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 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.

Further, examples of the functional group-containing acrylic monomer 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 has a 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.

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.

Particularly, the acrylic polymer used in the present invention preferably has at least one kind of group selected from the group consisting of hydroxyl group, carboxyl group, amino group, glycidyl group and amide group. The acrylic polymer having such a group has good reactivity with the polymer type silane coupling agent constituting the adhesive composition of the present invention or the crosslinking agent optionally blended.

The acrylic polymer used in the present invention has a weight average molecular weight of usually 100,000 to 15,000,000, preferably 300,000 to 800,000.

The acrylic polymer may be blended with other components such as an inorganic filler within the range that does not impair the object of the present invention.

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. The reaction solvent is usually used in an amount of 50 to 300 parts by weight based on 100 parts by weight of the total amount of monomers.

As the reaction initiator, for example, azobisisobutyronitrile, benzoyl peroxide, diester
-tert-Butyl peroxide and cumene hydroperoxide can be used. The reaction initiator is
Usually 0.01 per 100 parts by weight of total monomers
Used in an amount of from 10 to 10 parts by weight.

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.

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 containing the (co) polymer in an amount of 25 to 70% by weight in the reaction solvent. 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 pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
It is composed of the above acrylic polymer and a specific polymer type silane coupling agent. This polymer-type silane coupling agent has a functional group for an inorganic substance such as a glass substrate and a functional group for an organic substance such as an acrylic polymer as an adhesive component, and further has an affinity for the acrylic polymer. It is preferable to have a group having.

This polymer type silane coupling agent is
It has a functional group for inorganic substances. The inorganic substance involved in the adhesive composition of the present invention is mainly the glass substrate of the liquid crystal device, and the functional group for the inorganic substance present in the polymer type silane coupling agent in the present invention is functional to the glass substrate of the liquid crystal device. have. Examples of the group having functionality with respect to the inorganic substance include alkoxy groups such as methoxy group and ethoxy group. Of these groups, a single type of group may be introduced into the polymer-type silane coupling agent, or a plurality of types of groups may be introduced.

Further, this polymer type silane coupling agent has a functional group for an organic substance. The organic substance in which the polymer-type silane coupling agent participates is mainly an acrylic polymer forming an adhesive composition and a crosslinking agent optionally blended, and the functional group for the organic substance is an acrylic polymer or a crosslinking agent. It has reactivity. Examples of functional groups for such organic substances include epoxy groups, hydroxyl groups, carboxy groups, and amino groups. Of these groups, a single type of group may be introduced into the polymer-type silane coupling agent, or a plurality of types of groups may be introduced. Particularly, a coupling agent having a functional group for an organic substance as an epoxy group or a hydroxyl group is particularly preferable.

Further, examples of the group having an affinity for the acrylic polymer, which the polymer type silane coupling agent preferably has, are polyether groups,
Mention may be made of alkyl groups, polyester groups and aralkyl groups. Of these groups, a single type of group may be introduced into the polymer-type silane coupling agent, or a plurality of types of groups may be introduced. The group as described above has a good affinity for the acrylic polymer, and by introducing such a group, the affinity of the polymer type silane coupling agent for the acrylic polymer as the adhesive component is improved, Phase separation is less likely to occur.

The polymer type silane coupling agent having a group as described above has a skeleton in which a plurality of alkyl siloxanes are bonded, a skeleton in which a plurality of aryl siloxanes are bonded, or a plurality of alkyl siloxanes and aryl siloxanes are mixed and bonded. A part of an alkyl group or an aryl group having a skeleton and directly bonded to a silicon atom forming such a skeleton is a functional group for the inorganic substance, a functional group for the organic substance, or an acrylic polymer. Substituted with a group having an affinity for.

It is also considered that the alkyl group and aryl group of the alkyl siloxane or aryl siloxane for forming the main chain also act as a group having an affinity for the acrylic polymer. To be

Further, the molecular end of the main chain of such a polymer type silane coupling agent is usually end-capped with three alkyl groups or aryl groups, and 2 having three alkyl groups or aryl groups. The chain having the largest number of silicon atoms between the individual silicon atoms is the main chain in the present invention.

As an example of such a polymer type silane coupling agent, a compound represented by the following formula [I] can be mentioned.

[0043]

[Chemical 1]

However, in the above formula [I], X has an alkoxy group which is a functional group for an inorganic substance, and Y is
It has at least one kind of group selected from the group consisting of an epoxy group, a carboxy group, a hydroxyl group and an amino group, which is a functional group for an organic substance. Further, R independently represents one or both of an alkyl group and an aryl group, and Z is a polyether group, an alkyl group, an aryl group, an aralkyl group, which is a group having an affinity for an acrylic polymer. And at least one type of group selected from the group consisting of polyester groups.

When m, n, p and q are shown in relative proportions, n is usually 0.1 to 5 per 100 mol% of m.
0 mol%, p is usually 0.1 to 50 mol%, q is usually 0.1
˜50 mol%. The above repeating units are randomly combined to form the polymer type silane coupling agent used in the present invention.

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
The polymer type silane coupling agent is contained in an amount of 0.001 to 4 parts by weight, preferably 0.005 to 2 parts by weight, based on 100 parts by weight of the acrylic polymer.
If the amount added exceeds 4 parts by weight, the compatibility with the above-mentioned acrylic polymer will decrease. The addition amount is 0.001
If the amount is less than the weight part, the peelability at the time of producing the liquid crystal element and the durability under high temperature and high humidity conditions, which are the objects of the present invention, are not exhibited.

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
Immediately before use, the acrylic polymer and the polymer type silane coupling agent are mixed and used in an amount within the above range. Therefore, both are usually packaged separately for storage, transportation, and the like.

By using this polymer type silane coupling agent having a siloxane skeleton as the main chain, the pressure-sensitive adhesive composition of the present invention can be used as a substrate, particularly a glass substrate, a polarizing plate or a polarizing plate and a retardation plate. And a laminated plate of
300-2000g / 25 measured by the method specified by IS
It can be bonded with a bonding strength of about 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.

Although the reason why the pressure-sensitive adhesive composition for liquid crystal element of the present invention has necessary and sufficient adhesive strength by blending such a polymer type silane coupling agent, it is not clear. The functional group of the polymer-type silane coupling agent for the organic substance, and optionally the functional group for the acrylic polymer and the coupling agent and the functional group for the inorganic substance, which are provided by the group having an affinity for the acrylic polymer. The bond strength between the substrate and this coupling agent and the releasability inherent in the silicon compound are balanced, and the required adhesive strength is secured without excessively increasing the adhesive strength. It is presumed that

The pressure-sensitive adhesive composition for liquid crystal elements of the present invention comprises
In addition to the above components, other components can be blended, and examples of the other components used here include a tackifier, a plasticizer, a crosslinking agent, and a dye. The above-mentioned other components can be blended alone or in combination.

Further, in the pressure-sensitive adhesive composition for liquid crystal devices of the present invention, a crosslinking agent such as a polyisocyanate compound, an epoxy compound, a melamine compound and a metal chelate is added to 100 parts by weight of the acrylic polymer. .0
It is preferable to add it in an amount of 01 to 10 parts by weight. Since these cross-linking agents are also reactive with the functional groups of the polymer-type silane coupling agent with respect to the organic substance, by using such a cross-linking agent, an acrylic resin having a cross-linked structure with the polymer-type silane coupling agent is formed. Good bond strength is developed with the polymer.

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 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 with a sealing material 6. 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 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 a liquid crystal device, which comprises a polymer-type silane coupling agent and an acrylic polymer, and a substrate surface and a polarizing plate surface (or a laminated plate comprising a polarizing plate and a retardation plate). Adhesive strength with a suitable strength is developed between the plate surface). 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.

[0064]

The pressure-sensitive adhesive composition for a liquid crystal element of the present invention contains an acrylic polymer and a specific polymer type silane coupling agent. The plate or the laminated plate of the polarizing plate and the retardation plate can be adhered with an adhesive 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 the glass substrate can be peeled off during the peeling. 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 even 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 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.

[0068]

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.

[0069]

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. After 2 hours, 10 parts by weight of the thus-prepared solution of azobisisobutyronitrile was added dropwise to the reaction solution heated to 63 ° 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.

220 parts by weight of the above reaction liquid (corresponding to 100 parts by weight of acrylic polymer) was added to the polymer type silane coupling agent [A] (trade name: MAC-2101, manufactured by Nippon Unicar Co., Ltd.) [main chain: poly Dimethyl siloxane (containing polyether group in side chain, functional group: alkoxy group, epoxy group) 0.02 parts by weight and polyisocyanate compound as a cross-linking agent (trade name: Coronate L, Nippon Polyurethane)
(Manufactured by K.K.) and well stirred to obtain the adhesive composition of the present invention.

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 thus adhered and the glass substrate is measured 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 The state of occurrence of foaming and peeling was evaluated by visual observation under the conditions.

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.

[0077]

[Example 2] In Example 1, instead of the polymer type silane coupling agent [A], a polymer type silane coupling agent [B] (trade name: MAC-2301, manufactured by Nippon Unicar Co., Ltd.) [main chain : Polydimethylsiloxane (containing polyether group in side chain, functional group: alkoxy group, hydroxyl group) An adhesive composition of the present invention was obtained in the same manner except that 0.04 part by weight was 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.

[0079]

Comparative Example 1 An adhesive composition was obtained in the same manner as in Example 1, except that the polymer type silane coupling agent [A] 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.

[0081]

Comparative Example 2 An adhesive was prepared in the same manner as in Example 1, except that the polymer type silane coupling agent [A] was not used and 0.2 part by weight of γ-glycidoxytrimethoxysilane [C] was used. A 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.

[0083]

[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]

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

Claims (6)

[Claims] 1. An acrylic polymer, and a polymer-type silane coupling agent having a functional group for an inorganic substance and a functional group for an organic substance, and a main chain formed of a siloxane skeleton, and 100 parts by weight of the acrylic polymer. On the other hand, a pressure-sensitive adhesive composition for a liquid crystal device, which contains the polymer type silane coupling agent in an amount of 0.001 to 4 parts by weight. 2. The polymer type silane coupling agent,
In addition to having a functional group for an inorganic substance and a functional group for an organic substance, it further has a group having an affinity for the acrylic polymer, the functional group for an inorganic substance is an alkoxy group, and the functional group for an organic substance is epoxy. Group, a hydroxyl group, a carboxy group and an amino group, which is at least one kind of group, and has an affinity for the acrylic polymer, a group such as a polyether group, an alkyl group, an aryl group, an aralkyl group and a polyester. The pressure-sensitive adhesive composition for liquid crystal devices according to claim 1, which is at least one kind of group selected from the group consisting of groups. 3. The polymer-type silane coupling agent has a siloxane skeleton in which either or both of a polyalkylsiloxane skeleton and / or a polyarylsiloxane skeleton are mixed, and is directly bonded to a silicon atom forming the siloxane skeleton. 3. A part of the alkyl group or aryl group which is present is substituted with a group having an affinity for the acrylic polymer, a functional group for an inorganic substance, or a functional group for an organic substance. A pressure-sensitive adhesive composition for a liquid crystal device. 4. The acrylic polymer is a copolymer of 60 to 99% by weight of alkyl (meth) acrylate, 1 to 20% by weight of a monomer having a functional group, and 0 to 20% by weight of another copolymerizable monomer. The adhesive composition for a liquid crystal device according to claim 1, wherein the adhesive composition is used. 5. The pressure-sensitive adhesive composition for liquid crystal devices according to claim 1, further comprising 0.1 part by weight of acrylic polymer.
The pressure-sensitive adhesive composition for a liquid crystal device according to claim 1, further comprising 001 to 10 parts by weight of a crosslinking agent. 6. A liquid crystal device 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. A polymer type silane cup in which a polarizing plate or a laminated plate of a polarizing plate and a retardation plate has an acrylic polymer and a functional group for an inorganic substance and a functional group for an organic substance on the surface, and the main chain is formed of a siloxane skeleton. A pressure sensitive adhesive composition comprising a ring agent and containing the polymer type silane coupling agent in an amount of 0.001 to 4 parts by weight with respect to 100 parts by weight of the acrylic polymer. Liquid crystal device characterized by.