JP2002250814A - Adhesive optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive optical film with an adhesive layer arranged thereon to stick an optical film to a glass substrate of a liquid crystal panel, having excellent durability even under a condition such as heating and humidifying, bringing about little variation in dimensions of a base material forming the optical film and little failure caused by the adhesive. SOLUTION: In the adhesive optical film with the adhesive layer to stick the optical film to the glass substrate of the liquid crystal panel laminated on one surface of the optical film, the adhesive optical film is characterized by having <=0.08% dimensional coefficient of expansion of the optical film generated after being let alone for 24 hours in a 60 deg.C/90%RH(relative humidity) atmosphere, and having <=0.20% dimensional coefficient of contraction of the optical film generated after being let alone for 100 hours in a 90 deg.C/5%RH atmosphere in a state in which the adhesive layer of the adhesive optical film is stuck to the outermost surface of the liquid crystal panel and fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive type optical film in which an adhesive layer for attaching the optical film to a glass substrate of a liquid crystal panel is laminated on one surface of the optical film. Further, the present invention relates to a liquid crystal display device using the adhesive optical film. Examples of the optical film include a polarizing film, a retardation film, an optical compensation film, a brightness enhancement film, an antiglare sheet, and a laminate of a plurality of these.

[0002]

2. Description of the Related Art In a liquid crystal display, it is indispensable to arrange polarizing elements on both sides of a glass substrate forming the outermost surface of a liquid crystal panel in view of an image forming method. Affixed to the surface. In addition to the polarizing film on the outermost surface of the liquid crystal panel,
Various optical elements have been used to improve the display quality of a display. For example, a retardation film for preventing coloration, a viewing angle widening film for improving the viewing angle of a liquid crystal display, and a brightness enhancement film for increasing the contrast of the display are used. These films are collectively called optical films.

When the optical film is attached to the outermost surface of a liquid crystal panel, an adhesive is usually used. In addition, since the optical film can be instantaneously fixed to the outermost surface of the liquid crystal panel, and there is a merit that a drying step is not required to fix the optical film, the adhesive is applied to one side of the optical film in advance. It is provided as a layer. That is, an adhesive optical film is generally used for attaching the optical film to the outermost surface of the liquid crystal panel.

[0004] The required properties of the pressure-sensitive adhesive are as follows: (1) When bonding an optical film to the outermost surface of a liquid crystal panel, the bonding position is incorrect, or a foreign substance is caught in the bonding surface. In addition, the optical film can be peeled off from the outermost surface of the liquid crystal panel and bonded (reworked) again. (2) It has a stress relaxation property to prevent optical unevenness caused by a dimensional change of the optical film.
(3) In the endurance test by heating, humidification, and the like, which is usually performed as an environmental acceleration test, there is no problem caused by the adhesive.

[0005] In particular, in the environmental promotion test (3), the dimensional change of the base material forming the optical film causes a problem such as peeling at the interface between the adhesive laminated on the optical film and the glass on the outermost surface of the liquid crystal panel. There was a problem that occurs. For example, in an optical film, stretched polyvinyl alcohol, which can be a layer having a polarizing function, undergoes dimensional shrinkage by a heating test, and triacetyl cellulose used as a protective layer of the optical film absorbs water by a humidification test to expand dimensional expansion. Wake up.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a pressure-sensitive adhesive optical film provided with a pressure-sensitive adhesive layer for bonding the optical film to a glass substrate of a liquid crystal panel. An object of the present invention is to provide a pressure-sensitive adhesive optical film having good durability, a small dimensional change of a base material forming an optical film, and a small problem caused by a pressure-sensitive adhesive.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and have found that the above object can be achieved by the following pressure-sensitive adhesive optical film, and have completed the present invention.

That is, the present invention relates to an adhesive optical film in which an adhesive layer for attaching the optical film to a glass substrate of a liquid crystal panel is laminated on one surface of the optical film. 60 ° C./90 with the layer fixed to the outermost surface of the liquid crystal panel
% RH of the optical film after leaving for 24 hours in an atmosphere of% RH is 0.08% or less, and 90% or less.
The present invention relates to a pressure-sensitive adhesive optical film, characterized in that the dimensional shrinkage of the optical film that occurs after being left for 100 hours in an atmosphere of ° C./5% RH is 0.20% or less.

The pressure-sensitive adhesive optical film of the present invention can be used under a humidifying condition (60 ° C./90% R
H for 24 hours) or under heating conditions (90 ° C
(Left in an atmosphere of / 5% RH for 100 hours). The pressure-sensitive adhesive optical film of the present invention has a small dimensional expansion coefficient of 0.08% or less under the humidifying condition. It is preferable that the dimensional expansion coefficient is 0.05% or less. Also,
The pressure-sensitive adhesive optical film of the present invention has a small dimensional shrinkage of 0.20% or less under the heating conditions. The dimensional shrinkage is preferably 0.14% or less.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive optical film is an acrylic polymer having a monomer unit of alkyl (meth) acrylate as a main skeleton and containing a monomer unit having a carboxyl group and / or a hydroxyl group. It is preferable to include those crosslinked by the following. Preferably, the polyfunctional compound is a polyfunctional metal chelate. Such a crosslinked product can realize the adhesive optical film.

Further, the present invention relates to a liquid crystal display device using the above-mentioned adhesive optical film. The pressure-sensitive adhesive optical film of the present invention is used by being bonded to a glass substrate on the outermost surface of a liquid crystal panel.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive optical film of the present invention is such that the dimensional change of the optical film is not more than the above even under the above-mentioned humidifying condition or heating condition. Those can be used without particular limitation.

The pressure-sensitive adhesive that fixes the liquid crystal panel to the optical film causes a change in the dimensions of the optical film due to its viscosity. To realize the pressure-sensitive adhesive optical film, the pressure-sensitive adhesive has a low viscosity. It is preferable to use an adhesive or an adhesive having improved adhesiveness to glass. Examples of the former pressure-sensitive adhesive include pressure-sensitive adhesives with increased elasticity and pressure-sensitive adhesives with an increased rate of reaction between the base polymer and the polyfunctional compound (improved the degree of cross-linking). Examples thereof include those to which a compound having a functional group capable of chemically bonding to glass is added, and those using a base polymer having such a functional group.

The dimensional change of the optical film fixed to the liquid crystal panel by the adhesive is smaller than the dimensional change caused by the optical film not fixed to the liquid crystal panel, though it depends on the physical properties of the adhesive. A change occurs in the range. Therefore, in the humidification and heating tests, it was visually confirmed that the occurrence of defects caused by the adhesive due to the dimensional change occurring in the optical film on the liquid crystal panel caused floating on the end face of the optical film and dragging of the adhesive. To determine its occurrence.

Examples of the adhesive include various adhesives such as a rubber adhesive, an acrylic adhesive, and a silicone adhesive.

Among these adhesives, alkyl (meth)
An acrylic polymer having a acrylate monomer unit as a main skeleton and containing a monomer unit having a carboxyl group and / or a hydroxyl group, which contains a polyfunctional compound, can be preferably used.
These acrylic polymer and polyfunctional compound are crosslinked in the adhesive layer. In addition, (meth) acrylate means acrylate and / or methacrylate, and has the same meaning as (meth) in the present invention.

Constituting the main skeleton of the acrylic polymer,
The average number of carbon atoms in the alkyl group of the alkyl (meth) acrylate is about 1 to 12. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate and the like, which can be used alone or in combination.
Of these, alkyl (meth) acrylates having 1 to 7 carbon atoms in the alkyl group are preferred.

Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and itaconic acid. As the monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, N-
Examples include hydroxyl group-containing monomers such as methylol (meth) acrylamide, hydroxybutyl (meth) acrylate, and hydroxyhexyl (meth) acrylate.

In addition, as the acrylic polymer, a monomer having a functional group such as an epoxy group-containing monomer such as glycidyl (meth) acrylate, as well as vinyl acetate, styrene and the like are used as long as the performance of the adhesive is not impaired. You can also.

The proportion of the monomer unit (a) having a carboxyl group and / or a hydroxyl group in the acrylic polymer is not particularly limited, but the monomer unit (A) constituting the acrylic polymer (provided that the monomer unit (a) ) And the weight ratio (a / A)
It is adjusted to be about 0.001 to 0.12,
It is preferable in terms of durability. In particular, it is preferably 0.005 to 0.08.

The average molecular weight of the acrylic polymer is not particularly limited, but the weight average molecular weight is preferably about 300,000 to 2.5 million.

The acrylic polymer can be produced by various known methods. For example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, and a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo-based and peroxide-based ones can be used.
The reaction time is about 85 ° C. and the reaction time is about 1 to 8 hours. Among the above production methods, a solution polymerization method is preferable, and a polar solvent such as ethyl acetate or toluene is generally used as a solvent for the acrylic polymer. Solution concentration is usually 20-
It is about 80% by weight.

Examples of the polyfunctional compound include an organic crosslinking agent capable of crosslinking with the acrylic polymer and a polyfunctional metal chelate. In particular, the polyfunctional metal chelate functions as a cross-linking agent for the acrylic polymer as the base polymer, and also forms a chemical bond with glass to provide a certain degree of adhesiveness. Dimensional change of the optical film can be kept low.

Examples of the organic crosslinking agent include those having two or more functional groups which react with a carboxyl group or a hydroxyl group in one molecule, such as an epoxy crosslinking agent, an isocyanate crosslinking agent, and an imine crosslinking agent. Can be As the organic crosslinking agent, an isocyanate crosslinking agent is preferable.

The polyfunctional metal chelate is a polyvalent metal chelate having a covalent bond or a coordination bond with an organic compound.
Examples of polyvalent metal atoms include Al, Cr, Zr, Co, and C.
u, Fe, Ni, V, Zn, In, Ca, Mg, Mn,
Y, Ce, Sr, Ba, Mo, La, Sn, Ti and the like. Of these, Al, Zr, and Ti are preferred. The atom in the organic compound that forms a covalent bond or a coordinate bond includes an oxygen atom and the like, and the organic compound includes an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound and the like.

The mixing ratio of the acrylic polymer and the polyfunctional compound is not particularly limited, but is usually 0.01 to 6 parts by weight of the polyfunctional compound (solid content) per 100 parts by weight of the acrylic polymer (solid content). Parts, preferably 0.1 parts
About 3 parts by weight.

Further, the pressure-sensitive adhesive composition may further contain, if necessary, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like. Various additives can be appropriately used without departing from the scope.

In the pressure-sensitive adhesive optical film of the present invention, as shown in FIG. 1, an optical film 1 is provided with a pressure-sensitive adhesive layer 2 made of the pressure-sensitive adhesive composition. Further, a release sheet 3 can be provided on the adhesive layer 2.

As the optical film 1, a film used for forming a liquid crystal display device or the like is used, and the type thereof is not particularly limited. For example, examples of the optical film include a polarizing film, an elliptically polarizing film, a polarizing film having an optical compensation function, a polarizing film having a viewing angle expanding function, a polarizing film having a brightness improving function, and the like. In these, a retardation film, an optical compensation film, a brightness enhancement film, an antiglare sheet, and the like are laminated on a polarizing film.

As the polarizer constituting the polarizing film,
There is no particular limitation, and various types can be used. Examples of the polarizer include dichroic dyes such as iodine and dichroic dyes on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene-vinyl acetate copolymer-based partially saponified film. Examples thereof include a film obtained by adsorbing a substance and stretched, and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrochlorinated product of polyvinyl chloride. Although the thickness of the polarizer is not particularly limited, it is generally about 5 to 80 μm.

On one or both sides of the polarizer, a transparent protective layer can be provided as a coating layer of a polymer or a laminate layer of a film for the purpose of water resistance or the like. As the transparent polymer or film material for forming the transparent protective layer, an appropriate transparent material can be used, but a material having excellent transparency, mechanical strength, heat stability, moisture barrier property and the like is preferably used. Although the thickness of the transparent protective layer is not particularly limited, it is generally about 10 to 300 μm.

Materials for forming the transparent protective layer include:
For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulosic polymers such as cellulose diacetate and cellulose triacetate, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin) Polymers, polycarbonate polymers and the like. In addition, polyethylene, polypropylene, polyolefin having a cyclo- or norbornene structure, polyolefin polymers such as ethylene-propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, and sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Blends of polymers and the like are also examples of the polymer forming the transparent protective layer.

Examples of the retardation film include a birefringent film and a liquid crystal polymer film obtained by uniaxially or biaxially stretching a polymer material. Although the thickness of the retardation film is not particularly limited, it is generally about 20 to 150 μm. The retardation plate can be formed as a superimposed body of two or more stretched films to control the optical properties such as retardation, etc. It can also be used as an elliptically polarizing film laminated with a polarizing film to compensate for a phase difference or the like.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, and polyethylene naphthalate. Ether sulfone, polyphenylene sulfide, polyphenylene oxide,
Examples include polyallyl sulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymers, and various binary and ternary copolymers, graft copolymers, and blends thereof. These polymer materials become oriented products (stretched films) by stretching or the like.

Examples of the liquid crystalline polymer include various types of main chain type and side chain type in which a conjugated linear atomic group (mesogen) imparting liquid crystal orientation is introduced into the main chain or side chain of the polymer. And so on. Specific examples of the main chain type liquid crystalline polymer include a structure in which a mesogen group is bonded by a spacer portion that imparts flexibility, such as a nematic-oriented polyester-based liquid crystalline polymer, a discotic polymer, and a cholesteric polymer. . Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a paraffin having a nematic alignment imparting property via a spacer portion including a conjugated atomic group as a side chain. And those having a mesogen moiety composed of a substituted cyclic compound unit. These liquid crystalline polymers are prepared by, for example, rubbing the surface of a thin film of polyimide or polyvinyl alcohol formed on a glass plate, or applying a liquid crystalline polymer solution on an alignment-treated surface such as obliquely deposited silicon oxide. It is performed by developing and heat-treating.

The polarizing film and the retardation film can be laminated and used, and can be a reflection type polarizing film, a semi-transmissive layer type polarizing film, a polarized light separating polarizing film and the like. In addition, the above-described optical films can be used as optical compensation films and other various viewing angle widening films. Further, examples of the optical films include a brightness enhancement film and the like. Further, the polarizing film may be provided with a reflection layer having a fine uneven structure on the surface to form an antiglare sheet.

The formation of the adhesive layer 2 is performed on one side of the optical film 1 to be adhered to a glass substrate of a liquid crystal panel. The forming method is not particularly limited, and examples thereof include a method of applying a pressure-sensitive adhesive composition (solution) to the optical film 1 and drying, and a method of transferring the pressure-sensitive adhesive composition using a release sheet 3 provided with a pressure-sensitive adhesive layer 2. The thickness of the adhesive layer 2 (dry film thickness) is not particularly limited.
It is preferably about 0 μm.

The constituent material of the release sheet 3 is as follows.
Examples thereof include paper, synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate. The surface of the release sheet 3 may be subjected to a release treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment as needed in order to enhance the releasability from the pressure-sensitive adhesive layer 2.

[0039]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. In each example, parts are parts by weight.

Example 1 (Preparation of adhesive) A reaction was carried out at about 60 ° C for 6 hours while stirring 100 parts of butyl acrylate, 2 parts of acrylic acid, 0.4 parts of azobisisobutyronitrile and 220 parts of ethyl acetate. Thus, an acrylic polymer solution having a weight average molecular weight of 1.2 million was obtained. To the acrylic polymer solution, 2 parts of a polyfunctional metal chelate, aluminum chelate A, manufactured by Kawaken Fine Chemical Co., was added to 100 parts of the polymer solid content,
An adhesive solution was prepared.

(Preparation of Adhesive Optical Film) Thickness 80 μm
m was stretched 5 times in an aqueous iodine solution and dried, and a triacetyl cellulose film was adhered to both sides via an adhesive to obtain a polarizing film. The pressure-sensitive adhesive solution prepared above was
Was applied on a release paper having a thickness of 25 μm so that the thickness after drying was 25 μm, and this was laminated on the polarizing film produced as described above to obtain an adhesive polarizing film.

Example 2 100 parts of butyl acrylate, 10 parts of 2-hydroxyethyl acrylate, azobisisobutyronitrile 0.1 part Four
The reaction was carried out at around 60 ° C. for 6 hours while stirring the mixture and 220 parts of ethyl acetate to obtain an acrylic polymer solution having a weight average molecular weight of 127,000. To the acrylic polymer solution, 2 parts of Coronate L manufactured by Nippon Polyurethane Co., Ltd., which is an isocyanate-based multifunctional compound, was added to 100 parts of the polymer solid content to prepare a pressure-sensitive adhesive solution. Further, in the same manner as in Example 1, an adhesive type polarizing film was produced using the adhesive solution.

Example 3 100 parts of butyl acrylate, 1 part of acrylic acid, 1 part of 2-hydroxyethyl acrylate, azobisisobutyronitrile 0.1 part The reaction was carried out at about 60 ° C. for 6 hours while stirring 4 parts and 220 parts of ethyl acetate.
360,000 acrylic polymer solutions were obtained. 0.6 parts of Coronate L (produced by Nippon Polyurethane Co., Ltd.), which is an isocyanate-based polyfunctional compound, and 100 parts of polymer solid content, and KBM-403 (produced by Konishi), which is a silane coupling compound, were added to the acrylic polymer solution. One part was added to prepare an adhesive solution. Further, in the same manner as in Example 1, an adhesive polarizing film was produced using the adhesive solution.

Comparative Example 1 100 parts of 2-ethyl-1-hexyl acrylate, 7 parts of acrylic acid, azobisisobutyronitrile 0.1 part. While stirring 4 parts and 220 parts of ethyl acetate, the mixture was reacted at about 60 ° C. for 6 hours to obtain an acrylic polymer solution having a weight average molecular weight of 1.14 million. To the acrylic polymer solution, 2 parts of a polyfunctional metal chelate, aluminum chelate A manufactured by Kawaken Fine Chemical Co., was added to 100 parts of the polymer solid content to prepare an adhesive solution. Further, in the same manner as in Example 1, an adhesive type polarizing film was produced using the adhesive solution.

Comparative Example 2 100 parts of butyl acrylate, 1 part of acrylic acid, azobisisobutyronitrile 0.1 part 4 parts and ethyl acetate 220
The reaction was carried out at about 60 ° C. for 6 hours while stirring the parts to obtain an acrylic polymer solution having a weight-average molecular weight of 1.32 million.
To the acrylic polymer solution, 0.6 part of Coronate L (produced by Nippon Polyurethane Co., Ltd.), which is an isocyanate-based polyfunctional compound, was added to 100 parts of polymer solid content to prepare an adhesive solution. Further, in the same manner as in Example 1, an adhesive type polarizing film was produced using the adhesive solution.

The following evaluation was performed on the pressure-sensitive adhesive polarizing films obtained in the above Examples and Comparative Examples. The evaluation results are shown in Tables 1 and 2.

[Evaluation] Measurement of dimensional change of the adhesive polarizing film fixed on a glass plate by a heating test and a humidification test and confirmation of defects The adhesive polarizing film produced as described above was 280 mm thick.
It was cut out to a size of × 210 mm and bonded to a Corning-free alkali glass # 1737 via an adhesive layer. The dimensions of the polarizing film formed on the glass plate were measured with a digital caliper, and a sample was subjected to a heating test (90 ° C./5% R
H, 100 hours) and a sample was subjected to a humidification test (60 ° C./90% RH, 24 hours). For each sample, the dimensional change rate (dimensional shrinkage rate, dimensional expansion rate) was calculated from the value obtained by measuring the initial dimension of the polarizing film immediately after being subjected to each test and the dimension after the test, by the following formula *. The results are shown in Tables 1 and 2. * Dimensional shrinkage = (initial dimension-dimension after test) / initial dimension x
100 (%) * Dimension expansion rate = (dimension after test-initial dimension) / initial dimension x
100 (%) In addition, 10 samples were put into the heating test or the humidification test, and after the test, defects (lifting, peeling,
Pressure-sensitive adhesive streaks) were visually observed. Tables 1 and 2 show the number of defective sheets.

[0048]

[Table 1]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a sectional view of an adhesive optical film of the present invention.

[Description of Signs] 1 Optical film 2 Adhesive layer 3 Release sheet

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // C09J 163/00 C09J 175/04 175/04 G02B 1/10 Z (72) Inventor Shigeo Kobayashi Ibaraki-shi, Osaka 1-1-2 Hozumi Nitto Denko Corporation (72) Inventor Akiko Ogasawara 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 2H049 BA02 BA06 BB13 BB51 BC22 2H091 FA07X FB12 FC25 FD06 GA17 LA13 2K009 BB02 CC24 CC45 DD01 EE00 4J004 AA10 AA17 AB01 CA02 CA03 CA04 CA05 CA06 CB03 CC03 DA04 DA05 DB03 FA05 GA01 4J040 DF041 DF051 EC002 EC231 EF181 EF261 GA05 GA07 GA11 GA22 NA43 MA09 LA05

Claims (4)

[Claims] 1. An adhesive optical film in which an adhesive layer for attaching the optical film to a glass substrate of a liquid crystal panel is laminated on one surface of the optical film, wherein the adhesive layer of the adhesive optical film is formed on the liquid crystal panel. The optical film has a dimensional expansion coefficient of 0.08% or less when left in an atmosphere of 60 ° C./90% RH for 24 hours in a state where the optical film is bonded and fixed to the outermost surface of the substrate, and 90 ° C./5% A pressure-sensitive adhesive optical film, wherein the dimensional shrinkage of the optical film that occurs after being left for 100 hours in an atmosphere of RH is 0.20% or less. 2. An acrylic polymer wherein the pressure-sensitive adhesive layer has a monomer unit of alkyl (meth) acrylate as a main skeleton and contains a monomer unit having a carboxyl group and / or a monomer unit having a hydroxyl group is a polyfunctional compound. 2. The pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive type optical film comprises a crosslinked product. 3. The pressure-sensitive adhesive optical film according to claim 2, wherein the polyfunctional compound is a polyfunctional metal chelate. 4. A liquid crystal display device using the pressure-sensitive adhesive optical film according to claim 1.