KR101145024B1 - Adhesive composition for discotic liquid crysltal layer and optical film with function for widening angle of vision field - Google Patents

Abstract

An object of the present invention is an optical functional film having a discotic liquid crystal layer for expanding the viewing angle

A pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer on the discotic liquid crystal layer of the present invention, which is excellent in adhesiveness with the adherend as well as with a discotic liquid crystal layer, and also has durability (heat resistance, water resistance, etc.) required for liquid crystal display applications. To provide a pressure-sensitive adhesive composition for a discotic liquid crystal layer capable of forming an excellent pressure-sensitive adhesive layer, and an optical functional film having a viewing angle enlargement function having the pressure-sensitive adhesive layer, which is mainly composed of an acrylic copolymer polymer and a tolylene diisocyanate type as a silane coupling agent and a crosslinking agent. The said subject is solved by setting it as the adhesive composition for discotic liquid crystal layers containing a crosslinking agent (X) and another crosslinking agent (Y).

Description

Adhesion composition for discotic liquid crystal layer and optical viewing film to enlarge viewing angle {ADHESIVE COMPOSITION FOR DISCOTIC LIQUID CRYSLTAL LAYER AND OPTICAL FILM WITH FUNCTION FOR WIDENING ANGLE OF VISION FIELD}

The present invention relates to a pressure-sensitive adhesive composition for a discotic liquid crystal layer and an optical functional film imparting a viewing angle enlargement function, and more particularly, to the discotic liquid crystal layer of an optical functional film having a discotic liquid crystal layer for expanding the viewing angle. A pressure-sensitive adhesive composition for forming an pressure-sensitive adhesive layer on a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer having excellent adhesion to a discotic liquid crystal layer and durability, and an optically functional film having a viewing angle enlargement function obtained by using the pressure-sensitive adhesive composition. It is about.

The basic configuration of a liquid crystal display is a liquid crystal panel in which a liquid crystal is sandwiched between two glass substrates. From the image display format, a polarizing element must be disposed on the surface of two glass substrates of a liquid crystal panel, and a polarizing film is usually attached. In addition, various optical functional films for improving the quality of the liquid crystal display, for example, retardation film, viewing angle magnification film (optical compensation film), brightness enhancement film and the like are disposed.

Among such optical functional films, as the viewing angle expanding film, an independent optical film in which an optically anisotropic layer in which an alignment layer of a liquid crystal polymer, in particular, a discotic liquid crystal is hybridized, is formed on a support film represented by a triacetyl cellulose film (TAC film). It was used in the form which sticks to a polarizing film and other optical functional films through an adhesive bond layer as a functional film.

However, for example, when sticking especially to a polarizing film, since a polarizing film sandwiches a polarizer (polyvinyl alcohol film etc. which adsorbed and oriented iodine) between two support films (TAC film etc.), an adhesive body enlarges a viewing angle. Together with the support film of a film, it has one layer of adhesive bond layers for bonding the support film of three sheets, the support film of a polarizing film, and the support film of a viewing angle expansion film.

On the other hand, the liquid crystal display is required to make the whole thickness thin with the expansion and diversification of the use.

Therefore, a polarizing film was produced using a film having a discotic liquid crystal layer formed in advance as one of the two supporting films, and a viewing angle expanding function imparting polarization form in which a discotic liquid crystal layer was formed directly on one supporting film of the polarizing film. It is proposed to set it as a film, and as a result, to set it as the polarizing film of the viewing angle expansion layer integrated type which was made thin as the size of one support film and one layer of adhesive bond layers.

In the case of the polarizing film of the viewing angle expanding layer integrated type, an adhesive layer is usually formed on the discotic liquid crystal layer and adhered to the glass substrate of the liquid crystal panel through the adhesive layer. In order to cut into chips (chip cut), the adhesive layer formed on the discotic liquid crystal layer is also cut at the same time.

As a method of forming the adhesive layer for optical functional films, such as a polarizing film, the acrylic resin containing the functional group reacting with an epoxy group conventionally, the silane compound which has a functional group reacting with an epoxy group, the compound which has at least 2 or more epoxy groups, and a crosslinking agent Using a pressure-sensitive adhesive composition containing an acrylic polymer having a carboxyl group and an isocyanate-based crosslinking agent (for example, see Patent Publication No. 1999 (1997) No. 292525) using a pressure-sensitive adhesive composition containing Moreover, the method of forming by crosslinking an adhesive composition so that the ratio of the said crosslinking agent which does not affect bridge | crosslinking may be 70% or more (for example, refer Unexamined-Japanese-Patent No. 2073).

However, such a conventional adhesive has no problem with the adhesion to the adherend (such as the glass substrate of the liquid crystal panel) as well as with the film such as the TAC film commonly used as the support of the optical functional film, but with the discotic liquid crystal layer. Adhesiveness is low and not enough.

Therefore, as described above, in the case of chip-cutting a viewing angle expansion function-providing polarizing film having an adhesive layer formed on the discotic liquid crystal layer, the pressure-sensitive adhesive layer near the cut surface is stuck to the cutting blade and removed from the discotic liquid crystal layer. Or performance problems. In addition, after the liquid crystal cell is attached to the glass substrate, the adhesive remains on the glass substrate when pulled off as necessary, resulting in a viscous residue.

The present invention has been made in view of the above-described prior art, and forms an adhesive layer having excellent adhesion to an adherend as well as adhesion to a discotic liquid crystal layer and excellent durability (heat resistance, water resistance, etc.) required for liquid crystal display applications. An object of the present invention is to provide a pressure-sensitive adhesive composition for a discotic liquid crystal layer and a viewing angle expanding function-providing optical functional film having the pressure-sensitive adhesive layer.

As a result of intensive studies, the inventors have found that the problem can be solved by using both a tolylene diisocyanate-based crosslinking agent (X) and other crosslinking agents (Y) as crosslinking agents of the acrylic polymer. The present invention has been completed based on these findings.

That is, the present invention,

(1) A pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer on the discotic liquid crystal layer of the optically functional film having a discotic liquid crystal layer for expanding the viewing angle, comprising tolylene diisocyanate as an silane coupling agent and a crosslinking agent based on an acrylic copolymer. Adhesive composition for discotic liquid crystal layers containing system type crosslinking agent (X) and another crosslinking agent (Y),

(2) The content of tolylene diisocyanate crosslinking agent (X) is 0.5 to 30 mmol as the functional group equivalent of the acrylic copolymer, and the content of the other crosslinking agent (Y) is 0.2 to the functional group equivalent of the acrylic copolymer. The pressure-sensitive adhesive composition for discotic liquid crystal layer of (1), characterized in that 10 mmol,

(3) Tolylene diisocyanate crosslinking agent (X) is tolylene diisocyanate or trimethylolpropane modified tolylene diisocyanate, The adhesive composition for discotic liquid crystal layers as described in said (1) or (2),

(4) Other crosslinking agent (Y) is xylylene diisocyanate type crosslinking agent, The adhesive composition for discotic liquid crystal layers in any one of said (1)-(3),

(5) an optical-functional film having a viewing angle enlargement function in which a discotic liquid crystal layer and a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition for a discotic liquid crystal layer according to any one of the above (1) to (4) are sequentially formed on the surface of the optical functional film, and

(6) The optical functional film is a polarizing film in which a polarizer is sandwiched between two support films to provide the viewing angle-expansion-providing optical functional film of (5) above.

In the adhesive composition for a discotic liquid crystal layer of the present invention (hereinafter may be simply referred to as an "adhesive composition"), the acrylic copolymer polymer is a copolymer of a monomer mixture mainly composed of (meth) acrylic acid alkyl esters, but has an alkyl group carbon number. What is obtained by copolymerizing the (meth) acrylic-acid alkylester which is 4 or more and a crosslinkable functional group containing monomer with another copolymerizable monomer as needed is preferable.

Examples of the (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group include butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate. ) Acyl acrylate. Moreover, the alkyl ester which has alicyclic group or aromatic groups, such as (meth) acrylic-acid cycloalkyl ester and (meth) acrylic-acid benzyl ester, may be sufficient. These may be used independently or may be used in combination of 2 or more type.

As a crosslinkable functional group containing monomer, it is a monomer which has functional groups, such as a polymerizable double bond, a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group in a molecule, Preferably a hydroxyl group containing unsaturated compound and a carboxyl group-containing unsaturated compound are Is used.

As a specific example of such a functional group containing monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth) (Meth) acrylic-acid hydroxyalkyl esters, such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate; (Meth) acrylic acid acetoacetoxymethyl; (Meth) acrylic acid monoalkyl aminoalkyl, such as (meth) acrylic acid monomethyl aminoethyl, (meth) acrylic acid monoethyl aminoethyl, (meth) acrylic acid monomethyl aminopropyl, and (meth) acrylic acid monoethyl aminopropyl; And ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These monomers may be used independently or may be used in combination of 2 or more type.

As another monomer which can be copolymerized, the (meth) acrylic-acid alkylester whose carbon number of an alkyl group is three or less, specifically, methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid propyl, acrylonitrile, acrylamide, Vinyl ester, such as vinyl acetate and a vinyl butyrate, etc. are mentioned.

These may be used independently or may be used in combination of 2 or more type.

In the acrylic copolymer, the content ratio of the structural unit derived from the (meth) acrylic acid alkyl ester monomer having 4 or more carbon atoms in the alkyl group is preferably 60% by weight or more in order to have the necessary adhesiveness.

That is, the range of the content rate of the structural unit derived from the (meth) acrylic-acid alkylester monomer whose carbon number of an alkyl group is four or more becomes like this. Preferably it is 6-99 weight%, Especially preferably, it is 8-95 weight%.

In the acrylic copolymer, the structural unit derived from the crosslinkable functional group-containing monomer contributes to the formation of three-dimensional crosslinks by the crosslinking agent and to increase cohesion. For this reason, the content rate of a crosslinkable functional group containing monomer becomes like this. Preferably it is 0.1 to 10 weight%, Especially preferably, it is 1 to 5 weight%.

The structural unit guide | induced from the other copolymerizable monomer can control the glass transition point (Tg) of an acryl-type copolymer polymer by introducing this, and can adjust the adhesive force and cohesion force of an adhesive layer. For this reason, the content rate of the structural unit derived from the other monomer which can be copolymerized becomes like this. Preferably it is 0-40 weight%, Especially preferably, it is 0-10 weight%.

In order for the glass transition point (Tg) of an acryl-type copolymer polymer to produce necessary adhesiveness, -10 degrees C or less is preferable, Especially preferably, it is -6O-1-10 degreeC.

In addition, the weight average molecular weight of the acrylic copolymer is preferably 10,000 or more in order to exclude adverse effects such as odor due to residual monomers or contamination of the adherend, and 200,000 or less in order to obtain the viscosity required for applying the pressure-sensitive adhesive. Do.

That is, the weight average molecular weight of an acrylic copolymer polymer becomes like this. Preferably it is only 10-200000, Especially preferably, it is only 20-150000.

In the adhesive composition of this invention, both a tolylene diisocyanate type crosslinking agent (X) and another crosslinking agent (Y) are contained as a crosslinking agent.

Here, as an example of tolylene diisocyanate type crosslinking agent (X), tolylene diisocyanate (TDI), trimethylolpropane modified tolylene diisocyanate (TDI-TMP), etc. are mentioned.

Examples of the other crosslinking agent (Y) include isocyanate crosslinking agents other than tolylene diisocyanate crosslinking agent (X), epoxy crosslinking agents, metal chelate crosslinking agents, aziridine crosslinking agents, and the like.

Examples of isocyanate-based crosslinkers other than the tolylene diisocyanate-based crosslinker (X) include hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hydrogenated tolylene diisocyanate, diphenylmethane Polyvalent isocyanate, such as diisocyanate, and the adduct of these polyisocyanate and a polyhydric alcohol, For example, trimethylolpropane modified XDI (XDI-TMP) etc. are mentioned.

Examples of the epoxy crosslinking agent include 1,3-bis (N, N'-diglycidyl aminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl-m-xylylenediamine and ethylene Glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidylamine and the like.

As an example of a metal chelate type crosslinking agent, the chelate compound which consists of acetylacetone or acetonic acid ester of divalent or more metals, such as aluminum, steel, iron, tin, zinc, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, For example, ethyl acetoacetate aluminum diisopropionate, aluminum tris (ethylacetoacetate), etc. are mentioned.

Examples of the aziridine-based crosslinking agent include trimethylolpropane-tri-β-aziridinyl propionate and bisisophthaloyl-1- (2-methylaziridine).

Among these other crosslinking agents (Y), xylylene diisocyanate-based crosslinking agents such as xylylene diisocyanate (XDI) and trimethylolpropane-modified XDI (XDI-TMP) are particularly preferable in terms of excellent durability after adhesion. .

These other crosslinking agents (Y) may be used individually by 1 type, or may be used in combination of 2 or more type.

In order to acquire the adhesiveness which content of the tolylene diisocyanate type crosslinking agent (X) in an adhesive composition has, the range of 0.5-30 mmol is preferable at the functional group equivalent of an acrylic copolymer, especially 100-20 mmol Range is preferred.

In order to obtain the required durability (heat resistance, water resistance, etc.), the content of the other crosslinking agent (Y) is preferably in the range of 0.2 to 10 mmol, in particular in the functional group equivalent of the acrylic copolymer, particularly in the range of 0.5 to 7 mmol. Range.

A silane coupling agent is added to the adhesive composition of this invention in order to improve the adhesiveness with respect to the liquid crystal cell (glass) under wet heat conditions, and to make it hard to lift or peel of optical functional films, such as a polarizing film and retardation film. .

As the silane coupling agent, an organosilicon compound having at least one alkoxy silyl group in its molecule is well suited for compatibility with the pressure-sensitive adhesive component and having a light transmittance, for example, a substantially transparent one. Examples of such silane coupling agents include vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-methacryloxypropyl trimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2 -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and the like.

The amount of the silane coupling agent added is preferably in the range of 0.1 to 10 parts by weight, and particularly preferably in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of the pressure-sensitive adhesive composition.

To the pressure-sensitive adhesive composition of the present invention, various known additives used in conventional pressure-sensitive adhesive compositions, for example, tackifiers, plasticizers, antioxidants, ultraviolet absorbers, and the like, can be added to the pressure-sensitive adhesive composition as desired. Can be.

The adhesive composition of this invention is for forming an adhesive layer on the said discotic liquid crystal layer of the optical functional film which has a discotic liquid crystal layer for viewing angle expansion.

This viewing angle enlargement discotic liquid crystal layer is an optically anisotropic layer which hybrid-oriented the discotic liquid crystal compound which is a uniaxial compound.

Discotic liquid crystal compounds were discovered by S. Chandrasekhar et al. And published in “Pramana” 9 , 471 (1977), for example by the authors et al. Under the title “Rep. Prog. Phys. " 53 (199O) 57 or by Takenaka Sunsuke under the heading" Design and Synthesis of Discotic Liquid Crystal Molecules ", as described in the Japanese Chemical Society, Journal of Biological Chemistry, vol. 22, p. 60. It is seen as a compound in which a relatively long side chain is bonded to the core of the phase.

Kinds of the compounds can be classified mainly according to the structure of the core, derivatives of 6-substituted benzene and 3-substituted benzene, derivatives of phthalocyanine and porphyrin, triphenylene, truxene, pyrylium And derivatives thereof, tribenzocyclononene derivatives, azacrown derivatives and cyclohexane derivatives.

5-100 micrometers is preferable and, as for the thickness of the adhesive layer formed on the discotic liquid crystal layer for viewing angle expansion, 10-50 micrometers is especially preferable.

As a method of forming this adhesive layer, for example, the said adhesive composition is directly apply | coated to a discotic liquid crystal layer by a well-known method, and the adhesive layer is formed, or the said adhesive composition is apply | coated by a well-known method on a peeling sheet, for example. After forming an adhesive layer, the method etc. which transfer this to a discotic liquid crystal layer can be used.

As a method of applying the pressure-sensitive adhesive composition, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater or the like is used. The method can be mentioned.

Moreover, as an optical functional film which has a discotic liquid crystal layer for viewing angle expansion to which the adhesive composition of this invention can be applied, the viewing angle of the form in which the discotic liquid crystal layer was formed directly on one support film of the above-mentioned polarizing film In addition to the expansion function-providing polarizing film, optical functional films other than the phase difference film of the form in which the discotic liquid crystal layer was formed similarly, and a brightness improving film can also be illustrated, for example.

Moreover, even when using a discotic liquid crystal layer as an independent optical functional film (film for viewing angle expansion) formed on a support film, when the adhesive layer needs to be formed in a discotic liquid crystal layer, the adhesive composition of this invention is effective. Can be applied.

Next, although an Example demonstrates this invention in more detail, this invention is not limited to this example at all.

In addition, each evaluation of the viewing angle expansion function provision polarizing film with an adhesive layer obtained by each example was performed according to the method shown below.

(1) adhesion

The polarizing film with pressure-sensitive adhesive layer and discotic liquid crystal layer was cut into 233 mm × 3O9 mm with a super cutter (manufactured by Ogino Precision Machinery Co., Ltd.), and the cut surface was visually inspected using a magnifying glass to observe the presence or absence of viscosity defects and Evaluated by reference.

◎: no viscosity defect

○: viscous defects of less than 100 µm in length

(Triangle | delta): Viscous defect of 100 micrometers or more in length in several places

×: There are a plurality of viscous defects

(2) reworkability

The polarizing film with an adhesive layer and the discotic liquid crystal layer of 125 mmx25 mm was affixed on the alkali free glass, and then autoclave-treated and left for 24 hours under the conditions of 23 degreeC 65% Rh, and then alkali free. It peeled off from the glass, the glass surface was visually confirmed, the presence or absence of a viscous residue was evaluated, and the following reference | standard evaluated. In addition, the sticking conditions and the peeling conditions were based on JIS Z 0237.

○: no viscous residue

△: some viscous residue

×: viscous residue

(3) durability

After attaching a 233 mm x 3O9 mm polarizing film with a pressure-sensitive adhesive layer and a discotic liquid crystal layer to an alkali-free glass, autoclave the process, and leaving it for 20 hours under conditions of drying at 80 ° C, the appearance of the polarizing film was changed using an magnifying glass. Observed and evaluated by the following criteria.

◎: no defect

○: micro bubbles, incontinence (less than 100 μm in length)

(Triangle | delta): Bubble and incontinence (length 100 micrometers or more)

×: There is peeling

In the following examples and comparative examples, the following were used as the acrylic copolymer.

(Polymer A): 99 weight part of acrylic acid n-butyl, 1 weight part acrylic acid, and 0.2 weight part of azobis isobutyronitrile (initiator) are added to 200 weight part of ethyl acetate, and the weight obtained by stirring at 65 degreeC for 17 hours. Only the average molecular weight 15O, a polymer of Tg -54 ℃.

(Polymer B): 89 parts by weight of n-butyl acrylate, 10 parts by weight of methyl acrylate, 1 part by weight of acrylic acid and 0.2 parts by weight of azobis isobutyronitrile (initiator) were added to 20 parts by weight of ethyl acetate and 17 at 65 ° C. Only the weight average molecular weight 13O obtained by stirring for time is a polymer of Tg -49 degreeC.

(Polymer C): 99 parts by weight of n-butyl acrylate, 1 part by weight of acrylic acid and 0.2 parts by weight of azobis isobutyronitrile (initiator) were added to 200 parts by weight of ethyl acetate and stirred at 75 ° C. for 10 hours, followed by acrylic acid A solution obtained by dissolving 49.5 parts by weight of n-butyl, 0.5 parts by weight of acrylic acid and 0.2 parts by weight of azobis isobutyronitrile (initiator) in 50 parts by weight of ethyl acetate was added dropwise over 4 hours, followed by stirring for 10 hours. Weight average molecular weight 1.2 million, Tg -54 degreeC polymer.

In addition, the thing comprised with the following four-layered constitution was used as a viewing angle expansion function provision (with a discotic liquid crystal layer) polarizing film.

20 μm thick polyvinyl alcohol film / thickness 100 μm TAC film / thickness 3 μm optically anisotropic layer (a discotic liquid crystal layer composed of triphenylene derivative)

Example 1

Toylene diisocyanate-based crosslinking agent (manufactured by Japan Polyurethane Co., Trademark: Colonate L) 1.6O parts by weight (functional group equivalent 7.32 mmol), xylylene diisocyanate-based crosslinking agent (Mitsui Takeda) ) Chemical product, brand name: Takenate D-11O N) O.6O weight part (functional group equivalent 2.58 mmol), and a silane coupling agent [Shin-Etsu Chemical Co., Ltd. brand name: KBM-3O3, 2- (3, 4- epoxy cyclohexyl) ) Ethyl trimethoxysilane] O. 6 parts by weight was added, and diluted with ethyl acetate to a concentration of 25% by weight to obtain an adhesive composition solution.

The coating thickness after drying was 25 micrometers on the peeling process surface of the peeling film (The peeling film which peeled off to polyethylene terephthalate film of 38 micrometers in thickness, product made by Lintec, brand name: SP-PET 3811 by the knife coater) with a knife coater. It applied so that it might dry and it dried at 90 degreeC for 1 minute, and formed the adhesive layer. Next, the release film with an adhesive layer was laminated | stacked on the polarizing film with a discotic liquid crystal layer so that an adhesive layer and a discotic liquid crystal layer may contact.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 2

A polarizing film with an adhesive layer and a discotic liquid crystal layer was obtained in the same manner as in Example 1 except that the amount of the tolylene diisocyanate-based crosslinking agent was changed from 1.6 parts by weight to 0.4 parts by weight (functional group equivalent 1.83 mmol). .

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 3

A polarizing film with an adhesive layer and a discotic liquid crystal layer was obtained in the same manner as in Example 1 except that the amount of the tolylene diisocyanate crosslinking agent was changed from 1.6 parts by weight to 3.2O parts by weight (functional group equivalent: 14.61 mmol).

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 4

A pressure-sensitive adhesive layer and a discotic liquid crystal layer were prepared in the same manner as in Example 1 except that the amount of the xylylene diisocyanate-based crosslinking agent was changed from 0.6 parts by weight to 0.15 parts by weight (functional group equivalent amount of 0.63 mmol). A polarizing film was obtained.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 5

A polarizing film with an adhesive layer and a discotic liquid crystal layer was prepared in the same manner as in Example 1 except that the amount of the xylylene diisocyanate-based crosslinking agent was changed from 0.6 parts by weight to 1.2 parts by weight (functional equivalent 5.13 mmol). Got it.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 6

Except having changed the polymer A into the polymer B of the same weight, it carried out similarly to Example 1, and obtained the polarizing film with an adhesive layer and a discotic liquid crystal layer.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 7

Except having changed the polymer A into the polymer C of the same weight, it carried out similarly to Example 1, and obtained the polarizing film with an adhesive layer and a discotic liquid crystal layer.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1.

Example 8

The polymer A was changed to the polymer C of the same weight, and 0.16 parts by weight of the xylylene diisocyanate-based crosslinking agent was added to 0.24 parts by weight (functional group equivalent of 2.6O mmol) of the epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-C). Except having changed, it carried out similarly to Example 1, and obtained the polarizing film with an adhesive layer and a discotic liquid crystal layer.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 9

The polymer A was changed to the polymer C of the same weight, and the amount of the xylylene diisocyanate-based crosslinking agent O.6O parts by weight was 0.23 parts by weight of the aluminum chelate-based crosslinking agent (manufactured by Kawaken Fine Chemicals, trade name: ALCH-TR). Except having changed into (functional group equivalent 2.61 mmol), it carried out similarly to Example 1, and obtained the polarizing film with an adhesive layer and a discotic liquid crystal layer.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Example 10

O.37 parts by weight of aziridine-based crosslinking agent (trade name: TAZM) by changing the polymer A into a polymer C having the same weight and further adding O.6O parts by weight of the xylylene diisocyanate-based crosslinking agent (trade name: TAZM) 2.58 mmol) was obtained in the same manner as in Example 1 to obtain a polarizing film with an adhesive layer and a discotic liquid crystal layer.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Comparative Example 1

Polarizing with pressure-sensitive adhesive layer and discotic liquid crystal in the same manner as in Example 1 except that only 1.60 parts by weight (functional group equivalent of 7.32 mmol) of tolylene diisocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., brand name: Colonate L) was used. A film was obtained.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Comparative Example 2

A pressure-sensitive adhesive layer and disco in the same manner as in Example 1, except that only xylylene diisocyanate-based crosslinking agent (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takenate D-11ON) was used in an amount of 0.6 parts by weight (functional group equivalent of 2.58 mmol). The polarizing film with a tick liquid crystal layer was obtained.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Comparative Example 3

Polarizing with pressure-sensitive adhesive layer and discotic liquid crystal in the same manner as in Example 1 except that only 24 parts by weight (functional group equivalent of 2.6O mmol) of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-C) was used as the crosslinking agent. A film was obtained.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

Comparative Example 4

Xylylene diisocyanate crosslinking agent (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takenate D-11ON) O.6O parts by weight (functional group equivalent 2.58 mmol) and epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: TETRAD-C) A polarizing film with an adhesive layer and a discotic liquid crystal layer was obtained in the same manner as in Example 1 except that 0.24 parts by weight (functional group equivalent of 2.6O mmol) was used.

About the polarizing film with an adhesive layer and a discotic liquid crystal layer obtained in this way, adhesiveness, rework property, and durability were evaluated, and the result was shown in Table 1. FIG.

[Table 1]

Adhesion Reworkability durability Example 1 ◎  ○  ◎ Example 2 ◎  ○  ◎ Example 3 ◎  ○  ◎ Example 4 ◎  ○  ◎ Example 5 ◎  ○  ◎ Example 6 ◎  ○  ◎ Example 7 ◎  ○  ◎ Example 8 ○  ○  ◎ Example 9 ○  ○  ○ Example 10 ○  ○  ○ Comparative Example 1 ○  ○  × Comparative Example 2 ×  ×  × Comparative Example 3 ×  × △ Comparative Example 4 ×  ○ △

 ADVANTAGE OF THE INVENTION According to this invention, the adhesive for discotic liquid crystal layers which can form the adhesive layer excellent in adhesiveness with a to-be-adhered body as well as adhesiveness with a discotic liquid crystal layer, and also excellent durability (heat resistance, water resistance, etc.) required for a liquid crystal display use. The viewing angle expansion function provision optical functional film which has a composition and its adhesive layer can be provided.

Claims (6)

As an adhesive composition for forming an adhesive layer on the said discotic liquid crystal layer of the optical functional film which has a discotic liquid crystal layer for viewing angle expansion, Tolylene diisocyanate system as an acrylic copolymer, a silane coupling agent, and a crosslinking agent It contains a crosslinking agent (X) and a xylylene diisocyanate crosslinking agent (Y), The content of the tolylene diisocyanate-based crosslinking agent (X) is 0.5 to 30 mmol as the functional group equivalent of the acrylic copolymer, and the content of the xylylene diisocyanate-based crosslinking agent (Y) is the functional group equivalent of the acrylic copolymer. It is 2-10 mmol, The adhesive composition for discotic liquid crystal layers characterized by the above-mentioned. delete The method of claim 1, The tolylene diisocyanate-based crosslinking agent (X) is tolylene diisocyanate or trimethylolpropane-modified tolylene diisocyanate, the pressure-sensitive adhesive composition for a discotic liquid crystal layer. delete The optical-functional film with a viewing angle enlargement function in which the discotic liquid crystal layer and the adhesive layer which consists of the adhesive composition for discotic liquid crystal layers of Claim 1 or 3 are formed in order on the surface of an optical functional film. The method of claim 5, Said optical functional film is a polarizing film in which a polarizer is pinched | interposed into two support films, The optical-function film with a viewing angle expansion function characterized by the above-mentioned.