KR20140049941A - Optical film, method for producing same, polarizer and liquid crystal display - Google Patents

Abstract

Provided is an optical film capable of having great durability and decreasing perviousness to water vapor. The optical film contains a thermoplastic resin. The perviousness to water vapor of the optical film is less than and equal to 90 g/m^2/day and the modulus of any of a return direction of the optical film by drawing or a wide direction is more than and equal to 1.5 times of the modulus without drawing. Additionally, the perviousness to water vapor of the optical film after drawing is less than and equal to 0.9 times of before drawing. (wherein the perviousness to water vapor, in the method of JIS Z 0208, is a value of after 24 hours at 40 °C and 90% of relative humidity.).

Description

Optical film and its manufacturing method, polarizing plate and liquid crystal display {OPTICAL FILM, METHOD FOR PRODUCING SAME, POLARIZER AND LIQUID CRYSTAL DISPLAY}

This invention relates to an optical film, its manufacturing method, and a polarizing plate.

The present invention relates to a polarizing plate and a liquid crystal display device. In particular, it is related with the polarizing plate which is excellent in polarizer durability even in a high temperature, high humidity environment, and the liquid crystal display device which has this polarizing plate.

BACKGROUND ART A liquid crystal display device is widely used every year as a space saving image display device with low power consumption. Conventionally, the liquid crystal display device has a large drawback in that the viewing angle dependence of the display image is large. However, wide viewing angle liquid crystal modes such as VA mode have been put into practical use. As a result, the demand for liquid crystal display devices is rapidly increasing even in a market where high quality images such as televisions are required. It is expanding.

The basic configuration of the liquid crystal display device is to form polarizing plates on both sides of the liquid crystal cell. The polarizing plate described above plays a role of passing only light of a polarization plane in a predetermined direction, and the performance of the liquid crystal display device largely depends on the performance of the polarizing plate. A polarizing plate generally has the structure which bonded together the polarizer which consists of a polyvinyl alcohol film etc. which adsorbed and oriented iodine or a dye, and the transparent protective film on both front and back sides of the polarizer. As the polarizing plate protective film, a cellulose acylate-based polarizing plate protective film typified by cellulose acetate has been widely used because of its high transparency and easily securing adhesion with polyvinyl alcohol used for a polarizer.

In recent years, with the expansion of the use of liquid crystal display devices, large-size and high-definition applications of televisions and the like have been expanded, and demands for the quality of polarizing plates and polarizing plate protective films have also increased. In particular, large size and high quality liquid crystal display devices are required to be used in various harsh environments, such as, for example, outdoor electronic signage applications, and in various harsh high temperature environments. In view of the above, in recent years, polarizers used in liquid crystal displays have been used to suppress all changes in polarizer durability under various harsh high temperature environments, specifically, changes in orthogonal transmittance (hereinafter referred to as cross transmittance) of polarizers under high temperature and high humidity. It is strongly desired.

In order to improve polarizer durability in a high temperature environment, it is known that it is effective to suppress the invasion of water into a polarizer conventionally, For example, Patent Document 1 describes a film having a moisture permeability of 150 g / m 2/24 hr or less in a polarizing plate. A method for use in a protective film is disclosed.

Japanese Patent Application Laid-Open No. 11-142645

A liquid crystal display device is used not only in the conventional indoor use but also in a harsh environment, such as outdoors, and the performance which does not permeate moisture of the optical film of the outermost surface of a liquid crystal display device becomes important. This TV problem also has an influence of the tendency of the glass of a liquid crystal cell to become thin in the case of TV use which enlarges in recent years, and it becomes easy to bend, and the influence on the polarizing plate deterioration after elapse of time of high temperature, high humidity environment is concerned. In addition, in small and medium-sized devices such as tablet PCs and mobile applications, which are rapidly spreading in recent years, space-saving demands in thinner and liquid crystal display devices are high. Therefore, there is a strong demand for solving polarizer deterioration after elapse of high temperature and high humidity environment.

In view of the above circumstances, an object of the present invention is to provide an optical film excellent in durability and capable of reducing moisture permeability and a method of manufacturing the same.

Another object of the present invention is to provide a polarizing plate using the optical film. Another object of the present invention is to provide a liquid crystal display device in which polarization plate deterioration after elapse of high temperature and high humidity environment is improved.

The object of the present invention can be achieved by the following means.

[1] An optical film containing a thermoplastic resin,

The water vapor transmission rate of the above-mentioned optical film is 90 g / m <2> / day or less, and by extending | stretching, the elasticity modulus in any of the conveyance direction or the width direction of the above-mentioned optical film will be 1.5 times or more with respect to the elasticity modulus when not extending | stretching,

Also

The optical film whose moisture permeability after extending | stretching becomes 0.9 times or less before extending | stretching.

(However, the moisture permeability is a value after a lapse of 24 hours at 40 ° C. and a relative humidity of 90% by the method of JIS Z 0208.)

[2] The optical film according to [1], wherein the film thickness is 60 µm or less.

[3] An optical film having a functional layer having a thickness of 0.1 to 20 µm on at least one surface of the optical film according to [1] or [2].

[4] The water vapor transmission rate (C) of the optical film when the above-mentioned functional layer is laminated, and the water vapor transmission rate (D) when the above-mentioned functional layer is not laminated are C / D ≤ 0.9 [3] The optical film of description.

[5] The optical film according to any one of [1] to [3], in which the thermoplastic resin described above contains an acrylic resin having a cyclic structure.

[6] an optical film for producing an optical film having a water vapor transmission rate of 90 g / m 2 / day or less by stretching a film containing a thermoplastic resin such that the elasticity modulus of the conveying direction or the width direction is 1.5 times and the water vapor transmission rate is 0.9 times or less. Method for producing a film.

[7] A polarizing plate comprising at least one optical film according to any one of [1] to [5] as a protective film for the polarizer.

[8] liquid crystal cells,

It includes the polarizing plate of [7] arrange | positioned in at least one of this liquid crystal cell,

The liquid crystal display device arrange | positioned so that the above-mentioned optical film may become an outermost layer.

According to this invention, the optical film which can be excellent in durability, and can reduce water vapor transmission rate, and its manufacturing method can be provided. By using the optical film of this invention, the liquid crystal display device by which the polarizing plate deterioration after time-lapse of high temperature, high humidity environment was suppressed can be provided.

1 is a schematic view of a film production line for carrying out a solution film forming method.
2 is a top view of an example of the optical film of the present invention.

Below, the polarizing plate of this invention, its manufacturing method, the additive used for it, etc. are demonstrated in detail.

The description of constituent elements described below may be made based on a representative embodiment of the present invention, but the present invention is not limited to such embodiment. In addition, the numerical range shown using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

The term &quot; acrylic resin &quot; means a resin obtained by polymerizing a derivative of methacrylic acid or acrylic acid, and a resin containing the derivative. Moreover, when it does not specifically limit, "(meth) acrylate" shows an acrylate and a methacrylate, and "(meth) acryl" shows an acryl and methacryl.

In addition, the "ground axis direction" of an optical film is a direction in which refractive index becomes the largest in a film plane, and a "fast axis direction" shall mean the direction orthogonal to a slow axis in a film plane.

[Optical film]

The optical film of this invention is an optical film containing a thermoplastic resin, The water vapor transmission rate of the above-mentioned optical film is 90 g / m <2> / day or less, The elasticity modulus when the elasticity modulus of any of TD and MD is not extended by extending | stretching. It is 1.5 times or more with respect to, and the water vapor transmission rate after extending | stretching becomes 0.9 times or less before extending | stretching.

By stretching an optical film and making elastic modulus 1.5 times or more, it is thought that the orientation of a molecular chain becomes strong and the packing between molecules becomes dense. It is presumed that the effect of the present invention is obtained because the diffusivity of the water molecules is suppressed as compared with before stretching.

The optical film of this invention can also be manufactured by extending | stretching a thermoplastic resin, and can also be made to use the stretched thermoplastic resin as a transparent support body, and to provide the functional layer in the at least one surface. The functional layer may be formed on one surface of the transparent support or may be formed on both surfaces.

<Thermoplastic resin>

Hereinafter, the thermoplastic resin used by this invention is demonstrated.

In the optical film of the present invention, examples of the optimal thermoplastic resin include (meth) acrylic resins, polycarbonate resins, polystyrene resins, cycloolefin resins, and the like. You can choose from resin.

The (meth) acrylic resin is a concept including both a methacrylic resin and an acrylic resin. The (meth) acrylic resin also includes derivatives of acrylate / methacrylate, particularly (co) polymers of acrylate ester / methacrylate ester.

((Meth) acrylic resin)

It is preferable that the above-mentioned (meth) acrylic-acid resin has a repeating structural unit derived from a (meth) acrylic acid ester monomer as a repeating structural unit, and it is more preferable to have a cyclized structure.

The (meth) acrylic acid-based resin described above further comprises a repeating structural unit which is formed by polymerizing at least one selected from a hydroxyl group-containing monomer, an unsaturated carboxylic acid and a monomer represented by the following general formula (201) as a repeating structural unit. You may contain it.

General formula (201)

CH ₂ = C (X) R ²⁰¹

(Wherein R ²⁰¹ represents a hydrogen atom or a methyl group, X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, a -CN group, a -CO-R ²⁰² group, or a -O-CO-R ²⁰³ group) , R ²⁰² and R ²⁰³ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)

As said (meth) acrylic acid ester, For example, Acrylic acid ester, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and benzyl acrylate; Methacrylic acid such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate and benzyl methacrylate Esters; These may be used alone or in combination of two or more. Among these, methyl methacrylate is preferable at the point which is excellent in heat resistance and transparency.

When using the above-mentioned (meth) acrylic acid ester, the content rate in the monomer component provided to a polymerization process fully exhibits the effect of this invention, Preferably it is 10-100 weight%, More preferably, 25 It is-100 weight%, More preferably, it is 40-100 weight%, Especially preferably, it is 50-100 weight%.

As a hydroxyl-containing monomer mentioned above, For example, 2- (hydroxyalkyl) acrylic acid ester, such as (alpha)-hydroxymethyl styrene, (alpha)-hydroxyethyl styrene, and 2- (hydroxyethyl) acrylate; 2- (hydroxyalkyl) acrylic acid such as 2- (hydroxyethyl) acrylic acid; These may be used alone or in combination of two or more.

When using the hydroxyl-containing monomer mentioned above, the content rate in the monomer component provided to a polymerization process fully exhibits the effect of this invention, Preferably it is 0-30 weight%, More preferably, it is 0-20 It is weight%, More preferably, it is 0-15 weight%.

Examples of the unsaturated carboxylic acid described above include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid, and the like, and these may be used alone or in combination of two or more. You may also Of these, acrylic acid and methacrylic acid are particularly preferable from the viewpoint of fully exerting the effects of the present invention.

When using the above-mentioned unsaturated carboxylic acid, the content rate in the monomer component provided to a polymerization process fully exhibits the effect of this invention, Preferably it is 0-30 weight%, More preferably, it is 0-. 20 weight%, More preferably, it is 0-15 weight%, Especially preferably, it is 0-10 weight%.

As a monomer represented by the above-mentioned general formula (201), styrene, vinyltoluene, (alpha) -methylstyrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, vinyl acetate etc. are mentioned, These are used only 1 type, for example. You may use and 2 or more types together. Among these, styrene and (alpha) -methylstyrene are preferable at the point which fully exhibits the effect of this invention.

When using the monomer represented by general formula (201) mentioned above, the content rate in the monomer component provided to a polymerization process fully exhibits the effect of this invention, Preferably it is 0-30 weight%, More preferably Preferably it is 0-20 weight%, More preferably, it is 0-15 weight%, Especially preferably, it is 0-10 weight%.

The monomer component described above may form a lactone ring after polymerization. In that case, it is preferable to polymerize the monomer component to obtain a polymer having a hydroxyl group and an ester group in the molecular chain.

As a form of the polymerization reaction for superposing | polymerizing the above-mentioned monomer component and obtaining the polymer which has a hydroxyl group and ester group in a molecular chain, it is preferable that it is a polymerization form using a solvent, and solution polymerization is especially preferable.

For example, the lactone ring structure of Unexamined-Japanese-Patent No. 2007-316366, Unexamined-Japanese-Patent No. 2005-189623, WO2007 / 032304, WO2006 / 025445 is also preferable. to be.

(Lactone ring-containing polymer)

Although a lactone ring containing polymer will not be specifically limited if it has a lactone ring, Preferably it has a lactone ring structure represented by following General formula (401).

In general formula (401):

[Chemical Formula 1]

In general formula (401), R ⁴⁰¹ , R ⁴⁰² and R ⁴⁰³ each independently represent a hydrogen atom or an organic moiety having 1 to 20 carbon atoms, and the organic moiety may contain an oxygen atom. The organic residue having 1 to 20 carbon atoms is preferably a methyl group, an ethyl group, an isopropyl group, an n-butyl group or a t-butyl group.

The content rate of the lactone ring structure represented by the said General formula (401) in the structure of a lactone ring containing polymer becomes like this. Preferably it is 5-90 mass%, More preferably, it is 10-70 mass%, More preferably, it is 10- 60 mass%, Especially preferably, it is 10-50 mass%. The heat resistance of the obtained polymer and surface hardness tend to improve by making the content rate of a lactone ring structure 5 mass% or more, and the moldability of the obtained polymer improves by making the content rate of a lactone ring structure 90 mass% or less. Tends to be.

Although there is no limitation in particular about the manufacturing method of a lactone ring containing polymer, Preferably, after obtaining the polymer (p) which has a hydroxyl group and an ester group in a molecular chain by a polymerization process, it heat-processes the obtained polymer (p) It is obtained by performing the lactone cyclization condensation process which introduces a ring structure into a polymer.

The mass average molecular weight of the lactone ring-containing polymer is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, and particularly preferably 50,000 to 500,000.

As for a lactone ring containing polymer, the mass reduction rate in the range of 150-300 degreeC in dynamic TG measurement becomes like this. Preferably it is 1% or less, More preferably, it is 0.5% or less, More preferably, it is 0.3% or less. About the measuring method of dynamic TG, the method of Unexamined-Japanese-Patent No. 2002-138106 can be used.

Since the lactone ring-containing polymer has a high cyclization condensation reaction rate, there is little de-alcohol reaction during the manufacturing process of the molded article, and bubbles or silvery silver (silver streaks) are generated in the molded article after molding using this alcohol. Defects can be avoided. In addition, since the lactone ring structure is sufficiently introduced into the polymer by the high cyclization condensation reaction rate, the obtained lactone ring-containing polymer has high heat resistance.

When the lactone ring-containing polymer is a chloroform solution having a concentration of 15 mass%, the degree of coloration (YI) thereof is preferably 6 or less, more preferably 3 or less, further preferably 2 or less, particularly preferably 1 or less . When coloring degree (YI) is six or less, since the problem which transparency is impaired by coloring hardly arises, it can use preferably in this invention.

The lactone ring-containing polymer has a 5% mass reduction temperature in thermal mass spectrometry (TG), preferably 330 ° C or higher, more preferably 350 ° C or higher, even more preferably 360 ° C or higher. 5% mass reduction temperature in thermal mass spectrometry (TG) is an index of thermal stability, and when it is made 330 degreeC or more, it exists in the tendency for sufficient thermal stability to be exhibited easily. The thermal mass spectrometry can use the said dynamic TG measuring apparatus.

The lactone ring-containing polymer preferably has a glass transition temperature (Tg) of at least 115 ° C, more preferably at least 125 ° C, more preferably at least 130 ° C, particularly preferably at least 135 ° C, and most preferably at least 140 ° C Or more.

The total amount of residual volatile matter contained in the lactone ring-containing polymer is preferably 5,000 ppm or less, more preferably 2,000 ppm or less, still more preferably 1, 500 ppm, particularly preferably 1,000 ppm. If the total amount of remaining volatile matter is 5,000 ppm or less, it is preferable because molding defects such as coloring, foaming, or silver streaks are less likely to occur due to deterioration or the like during molding.

The lactone ring-containing polymer has a total light transmittance measured by a method according to ASTM-D-1003 for a molded article obtained by injection molding, preferably 85% or more, more preferably 88% or more, and still more preferably 90 It is% or more. A total light transmittance is an index of transparency, and when this is made into 85% or more, there exists a tendency for transparency to improve.

In the case of the polymerization form using a solvent, a polymerization solvent is not specifically limited, For example, Aromatic-hydrocarbon solvents, such as toluene, xylene, ethylbenzene; Ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; Ether solvents such as tetrahydrofuran; These may be used alone, or two or more of them may be used in combination.

Moreover, in the manufacturing method of this invention, since (meth) acrylic-type resin is melt | dissolved in an organic solvent and solution casting is formed, when the organic solvent at the time of synthesis | combination of (meth) acrylic-type resin performs melt film forming, It does not specifically limit, You may synthesize | combine using the high organic solvent of boiling point.

In the polymerization reaction, a polymerization initiator may be added, if necessary. As a polymerization initiator, for example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxy isopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate; Azo compounds such as 2,2'-azobis (isobutyronitrile), 1,1'-azobis (cyclohexanecarbonitrile) and 2,2'-azobis (2,4-dimethylvaleronitrile); These may be used alone or in combination of two or more. What is necessary is just to set the usage-amount of a polymerization initiator suitably according to the combination, reaction conditions, etc. of the monomer to be used.

The weight average molecular weight of a polymer can be adjusted by adjustment of the quantity of a polymerization initiator.

When performing polymerization, it is preferable to control so that the concentration of the produced polymer in a polymerization reaction mixture may be 50 weight% or less, in order to suppress gelation of a reaction liquid. Specifically, when the concentration of the produced polymer in the polymerization reaction mixture exceeds 50% by weight, it is preferable to add the polymerization solvent to the polymerization reaction mixture as appropriate to control it to be 50% by weight or less. The concentration of the resulting polymer in the polymerization reaction mixture is more preferably 45% by weight or less, still more preferably 40% by weight or less.

The form in which the polymerization solvent is appropriately added to the polymerization reaction mixture is not particularly limited, and a polymerization solvent may be added continuously, or a polymerization solvent may be added intermittently. By controlling the concentration of the polymer produced in the polymerization reaction mixture in this way, the gelation of the reaction solution can be more fully inhibited. Although the same kind of solvent as the solvent used at the time of the initial injection of a polymerization reaction may be sufficient as a polymerization solvent to add, and a different kind of solvent may be sufficient, but it is preferable to use the same kind of solvent as the solvent used at the time of initial injection of a polymerization reaction. Do. Moreover, 1 type of solvents may be sufficient as the polymerization solvent to add, and 2 or more types of mixed solvents may be sufficient as it.

The mass average molecular weight Mw of the acrylic resin used in the present invention is preferably 80000 or more. When the mass average molecular weight Mw of the acrylic resin is 80000 or more, the mechanical strength is high and the handling suitability at the time of film production is excellent. From this viewpoint, the mass average molecular weight Mw of the acrylic resin is preferably 100000 or more.

As the acrylic resin used in the present invention, commercially available acrylic resins may also be used. For example, Derpet 60N, 80N (manufactured by Asahi Chemical Chemicals Co., Ltd.), diamonds BR80, BR85, BR88, BR102 (manufactured by Mitsubishi Rayon Co., Ltd.), KT75 (manufactured by Denki Chemical Industries, Ltd.), etc. Can be mentioned.

Two or more acrylic resins may be used in combination.

(Polycarbonate Resin)

In the present invention, as the thermoplastic resin, a polycarbonate-based resin containing an additive in order to suitably control peeling force and toughness can be used.

(Polystyrene-based resin)

In the present invention, as the thermoplastic resin, a polystyrene-based resin containing an additive in order to suitably control peeling force and toughness can be used.

(Cyclic polyolefin resin)

In the present invention, a cyclic polyolefin-based resin can be used as the thermoplastic resin. Here, cyclic polyolefin type resin shows the polymer resin which has a cyclic olefin structure.

Examples of the polymer resin having a cyclic olefin structure for use in the present invention include (1) a norbornene-based polymer, (2) a polymer of a cyclic olefin of a single ring, (3) a polymer of a cyclic conjugated diene, and (4) vinyl Alicyclic hydrocarbon polymer, and the hydride of (1)-(4).

Preferred polymers for the present invention include at least one of an addition (co) polymer cyclic polyolefin-based resin containing at least one or more repeating units represented by the following general formula (II) and, if necessary, the repeating unit represented by the general formula (I). It is an addition (co) polymer cyclic polyolefin type resin which further contains a species or more. Moreover, the ring-opening (co) polymer containing at least 1 type of cyclic repeating unit represented by General formula (III) can also be used preferably.

(2)

(3)

[Chemical Formula 4]

M shows the integer of 0-4 in a formula (I)-(III). R ¹ to R ⁶ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, X ¹ to X ³ and Y ¹ to Y ³ are each independently a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or a halogen C1-C10 hydrocarbon group substituted by atoms,-(CH ₂ ) _n COOR ¹¹ ,-(CH ₂ ) _n OCOR ¹² ,-(CH ₂ ) _n NCO,-(CH ₂ ) _n NO ₂ ,-(CH ₂ ) _n CN,-(CH ₂ ) _n CONR ¹³ R ¹⁴ ,-(CH ₂ ) _n NR ¹³ R ¹⁴ ,-(CH ₂ ) _n OZ,-(CH ₂ ) _n W, or X ¹ and Y ¹ or X (-CO) ₂ O, (-CO) ₂ NR ¹⁵ composed of ² and Y ² or X ³ and Y ³ . In ^{addition, R 11, R 12, R} 13, R 14, R 15 each independently represent a hydrogen atom, a hydrocarbon group of 1 to 20 carbon atoms, Z is substituted by a hydrocarbon group or a halogenated hydrocarbon group, W is SiR ¹⁶ _p D _{3 -p} (R ¹⁶ D is a halogen atom, -OCOR ¹⁶ or -OR ^16, a hydrocarbon group, having a carbon number of 1 ~ 10 p represents an integer of 0 to 3), n represents an integer of 0 to 10.

By introducing a highly polarizable functional group into the substituents of X ¹ to X ³ and Y ¹ to Y ³ , the thickness direction retardation (Rth) of the optical film can be increased to increase the expression of the in-plane retardation (Re). Can be.

Norbornene-based polymer hydrides are disclosed in Japanese Patent Application Laid-Open No. Hei 1-240517, Japanese Patent Laid-Open No. 7-196736, Japanese Patent Laid-Open No. 60-26024, Japanese Patent Laid-Open No. 62-19801, and Japanese Laid-Open Patent Publication. As disclosed in Japanese Patent Laid-Open Publication No. 2003-159767 or Japanese Laid-Open Patent Publication No. 2004-309979 and the like, the polycyclic unsaturated compound is produced by hydrogenation after addition polymerization or metathesis ring-opening polymerization. In the norbornene-based polymer used in the present invention, R ⁵ to R ⁶ are preferably a hydrogen atom or -CH ₃ , X ³ and Y ³ are preferably a hydrogen atom, Cl, -COOCH ₃ , and other groups Appropriately selected. This norbornene-based resin is marketed under the trade names of Arton G or Aton F from JSR, and Zeonor ZF14, ZF16, Zeonex 250 or from Nippon Xeon It is marketed under the brand name Zeonex 280, and can be used.

Norbornene-based addition (co) polymers are disclosed in Japanese Patent Application Laid-Open No. H10-7732, Japanese Patent Application Laid-Open No. 2002-504184, US Publication No. 2004229157A1 or WO2004 / 070463A1. It is obtained by addition-polymerizing norbornene-type polycyclic unsaturated compounds. If necessary, a norbornene-based polycyclic unsaturated compound and at least one compound selected from the group consisting of ethylene, propylene, and butene; Conjugated dienes such as butadiene and isoprene; Non-conjugated dienes such as ethylidene norbornene; The linear diene compounds, such as acrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, acrylic acid ester, methacrylic acid ester, maleimide, vinyl acetate, vinyl chloride, can also be addition-polymerized. This norbornene-based addition (co) polymer is available from Mitsui Chemicals Co., Ltd. under the trade name of Apel, and has a different glass transition temperature (Tg), for example, APL8008T (Tg 70 ° C), APL6013T (Tg 125 ° C) or Grades such as APL6015T (Tg 145 ° C.). Pellets such as TOPAS8007, 6013 and 6015 are commercially available from Polyplastics Co., Ltd. Appear3000 is also being released from Ferrania.

In this invention, although there is no restriction | limiting in the glass transition temperature (Tg) of cyclic polyolefin type resin, High Tg cyclic polyolefin type resin of 200-400 degreeC can also be used, for example.

(Glutaric anhydride resin)

In the present invention, glutaric anhydride resin can be used as the thermoplastic resin. Here, glutaric anhydride type resin shows the polymer resin which has a glutaric anhydride unit.

It is preferable that the polymer which has a glutaric anhydride unit has a glutaric anhydride unit (henceforth a glutaric anhydride unit) represented by following General formula (101).

In general formula (101):

[Chemical Formula 5]

In General Formula (101), R ³¹ , R ³² Each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. In addition, the organic residue may contain an oxygen atom. R ³¹ and R ³² particularly preferably represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

It is preferable that the polymer which has a glutaric anhydride unit is an acrylic copolymer containing a glutaric anhydride unit. As an acryl-type thermoplastic copolymer, it is preferable to have a glass transition temperature (Tg) 120 degreeC or more from a heat resistant viewpoint.

As content of the glutaric anhydride unit with respect to an acryl-type thermoplastic copolymer, 5-50 mass% is preferable, More preferably, it is 10-45 mass%. By setting it as 5 mass% or more, More preferably, it is 10 mass% or more, the effect of heat resistance improvement can be acquired, and also the effect of a weather resistance improvement can also be obtained.

Moreover, it is preferable that the said acrylic thermoplastic copolymer contains the repeating unit further based on unsaturated carboxylic acid alkyl ester. As a repeating unit based on unsaturated carboxylic acid alkyl ester, it is preferable to represent with the following general formula (102), for example.

(102): - [CH ₂ -C (R ⁴¹ ) (COOR ⁴² )] -

In General Formula (102), R ⁴¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ⁴² is substituted with an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms, or a hydroxyl group or halogen having 1 or more carbon atoms or less. An aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms is shown.

The monomer corresponding to the repeating unit represented by General formula (102) is represented by following General formula (103).

(103): CH ₂ = C (R ⁴¹ ) (COOR ⁴² )

Specific examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyhexyl acrylate, and 2,3,4,5-tetrahydroxypentyl (meth) acrylate. Of these, methyl methacrylate is most preferably used . These may be used individually by 1 type, or may use 2 or more types together.

As for content of the unsaturated carboxylic acid alkyl ester unit with respect to the said acrylic thermoplastic copolymer, 50-95 mass% is preferable, More preferably, it is 55-90 mass%. The acrylic thermoplastic copolymer having a glutaric anhydride unit and an unsaturated carboxylic acid alkyl ester-based unit can be obtained by, for example, polymerizing and cyclizing a copolymer having an unsaturated carboxylic acid alkyl ester-based unit and an unsaturated carboxylic acid unit. Can be.

The unsaturated carboxylic acid unit is preferably represented by, for example, the following general formula (104).

(104): - [CH ₂ -C (R ⁵¹ ) (COOH)] -

R ⁵¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms.

As a preferable specific example of the monomer which derives an unsaturated carboxylic acid unit, the compound represented by following General formula (105) which is a monomer corresponding to the repeating unit represented by General formula (104), and maleic acid, and also maleic anhydride Although hydrolyzate etc. are mentioned, Acrylic acid and methacrylic acid are preferable at the point which is excellent in thermal stability, More preferably, it is methacrylic acid.

(105): CH ₂ = C (R ⁵¹ ) (COOH)

These may be used individually by 1 type, or may use 2 or more types together. As described above, the acrylic thermoplastic copolymer having a glutaric anhydride unit and an unsaturated carboxylic acid alkyl ester-based unit is polymerized and cyclized, for example, a copolymer having an unsaturated carboxylic acid alkyl ester-based unit and an unsaturated carboxylic acid unit. Since it can obtain by making it, you may have leaving an unsaturated carboxylic acid unit in the structural unit.

As content of the unsaturated carboxylic acid unit with respect to the said acrylic thermoplastic copolymer, 10 mass% or less is preferable, More preferably, it is 5 mass% or less. By setting it as 10 mass% or less, fall of colorless transparency and retention stability can be prevented.

Moreover, the acryl-type thermoplastic copolymer mentioned above may have another vinylic monomer unit which does not contain an aromatic ring in the range which does not impair the effect of this invention. As a specific example of the other vinylic monomer unit which does not contain an aromatic ring, Speaking corresponding monomer, Vinyl cyanide monomers, such as an acrylonitrile, methacrylonitrile, an ethacrylonitrile; Allyl glycidyl ether; Maleic anhydride, itaconic anhydride; N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide; Aminoethyl acrylate, propylaminoethyl methacrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate; N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallyl amine, N-methylallylamine; Oxazoline, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acyl-oxazoline and the like. These may be used individually by 1 type and may use 2 or more types together.

As content of the other vinylic monomer unit which does not contain the aromatic ring with respect to the said acrylic thermoplastic copolymer, 35 mass% or less is preferable.

In addition, about the vinyl-type monomeric unit (N-phenylmaleimide, phenyl amino ethyl methacrylate, p-glycidyl styrene, p-amino styrene, 2-styryl- oxazoline etc.) containing an aromatic ring, Since there exists a tendency for a fall in weatherability and weather resistance, it is preferable that it is only 1 mass% or less as content with respect to the acryl-type thermoplastic copolymer mentioned above.

(Glutarimide resin)

In the present invention, glutarimide-based resin can be used as the thermoplastic resin. Here, glutarimide-type resin represents the polymer resin which has a glutarimide unit.

The glutarimide-based resin mentioned above is a thermoplastic resin which has a substituted or unsubstituted imide group in a side chain. By having a substituted or unsubstituted imide group in a side chain, preferable characteristic balance can be expressed from an aspect, such as an optical characteristic or heat resistance. The glutarimide-based resin described above is at least the following general formula (301):

General Formula (301)

[Chemical Formula 6]

20 wt% or more of a glutarimide unit (wherein, R ³⁰¹ , R ³⁰² , and R ³⁰³ are each independently hydrogen or an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aryl group) It is desirable to have.

As a preferable glutimide unit which comprises the glutarimide-type resin used for this invention, R ³⁰¹ and R ³⁰² are hydrogen or a methyl group, and R ³⁰³ is a methyl group or a cyclohexyl group. A single kind may be sufficient as this glutarimide unit, and R ³⁰¹ , R ³⁰² , and R ³⁰³ may contain the some kind from which different.

As a preferable 2nd structural unit which comprises the glutarimide-type resin used for this invention, it is a unit which consists of an acrylic acid ester or methacrylic acid ester. Preferred examples of the acrylic ester or methacrylate ester structural unit include methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. Moreover, as another preferable imidable unit, N-alkyl methacrylamide, such as N-methylmethacrylamide and N-ethyl methacrylamide, is mentioned. These 2nd structural units may be individual types, and they may contain several types.

Content of the glutarimide unit represented by General formula (301) of glutarimide-type resin is 20 weight% or more based on the total repeating unit of glutarimide-type resin. Preferable content of a glutarimide unit is 20 to 95 weight%, More preferably, it is 50 to 90 weight%, More preferably, it is 60 to 80 weight%. When a glutarimide unit is smaller than this range, the heat resistance of the film obtained may be inadequate or transparency may be impaired. Moreover, when this range is exceeded, heat resistance will rise unnecessarily and it will become difficult to form a film, the mechanical strength of the film obtained will fall extremely, and transparency may be impaired.

As needed, the third structural unit may be copolymerized with the glutarimide resin. Examples of the preferred third structural unit include styrene monomers such as styrene, substituted styrene and α-methylstyrene, acrylic monomers such as butyl acrylate, nitrile monomers such as acrylonitrile and methacrylonitrile, maleimide and N The structural unit formed by copolymerizing maleimide-type monomers, such as -methyl maleimide, N-phenyl maleimide, and N-cyclohexyl maleimide, can be used. These may be directly copolymerized with this glutarimide unit and the unit which can be imidized in glutarimide-type resin, and may be graft-copolymerized with respect to resin which has this glutarimide unit and the unit which can be imidated. When a 3rd component adds this, it is preferable that content rate in glutarimide-type resin is 5 mol% or more and 30 mol% or less based on the total repeating unit in glutarimide-type resin.

Glutarimide-based resin is described in each of U.S. Patent No. 3284425, U.S. Patent No. 4246374, Japanese Patent Application Laid-Open No. 2-153904 and the like, and the main raw material is methacrylic acid methyl ester or the like as a resin having an imidable unit. It can obtain by imidating resin which has the above-mentioned imidable unit using resin obtained by making into the above, using ammonia or substituted amine. When obtaining glutarimide-type resin, the unit comprised from acrylic acid, methacrylic acid, or its anhydride may be introduce | transduced in glutarimide-type resin as a reaction by-product. Since the presence of such a structural unit, especially an acid anhydride, reduces the total light transmittance and haze of the optical film of this invention obtained, it is not preferable. The content of acrylic acid or methacrylic acid is preferably 0.5 milliequivalent or less, preferably 0.3 milliequivalent or less, and more preferably 0.1 milliequency or less, per 1 g of the resin. Moreover, as shown in Unexamined-Japanese-Patent No. 2-153904, it is also possible to obtain glutarimide-type resin by imidating using resin mainly consisting of N-methyl acrylamide and methacrylic acid methyl ester.

Moreover, it is preferable that glutarimide resin has a weight average molecular weight of 1 * 10 <^4> -5 * 10 <^5> .

(Other thermoplastic resin)

The thermoplastic of this invention may contain other thermoplastic resins other than the said resin. The other thermoplastic resins are not particularly problematic unless they are in violation of the spirit of the present invention, but thermodynamically compatible thermoplastic resins are preferred from the viewpoint of improving mechanical strength and desired physical properties.

As said other thermoplastic resin, For example, olefinic thermoplastics, such as polyethylene, a polypropylene, an ethylene propylene copolymer, and a poly (4-methyl-1- pentene); Halogen-containing thermoplastics such as vinyl chloride and vinyl chlorinated resin; Acrylic thermoplastics such as polymethyl methacrylate; Styrene-based thermoplastics such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer; Polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; Polyamides such as nylon 6, nylon 66 and nylon 610; Polyacetal; Polycarbonate; Polyphenylene oxide; Polyphenylene sulfide; Polyether ether ketone; Polysulfone; Polyether sulfone; Polyoxybenzylene; Polyamideimide; Rubber polymers such as ABS resin and ASA resin containing polybutadiene rubber and acrylic rubber; And the like. Moreover, it is preferable that it is 100 nm or less from a viewpoint of the transparency improvement at the time of making the average particle diameter of a rubbery polymer into a film form, and it is more preferable that it is 70 nm or less.

When a copolymer containing a vinyl cyanide monomer unit and an aromatic vinyl monomer unit is used, specifically, a polymer containing 50% by weight or more of acrylonitrile-styrene copolymer, polyvinyl chloride resin, and methacrylic acid esters is used. do. Among them, when an acrylonitrile-styrene copolymer is used, a film having a glass transition temperature of 120 ° C. or more and a phase difference per 100 μm in the plane direction of 20 nm or less and a total light transmittance of 85% or more can be easily obtained.

<Additives>

(Fine particles made of mat)

Microparticles | fine-particles can be added to the optical film of this invention as a mat agent. Examples of the fine particles used as the mat agent include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, calcium silicate hydrate, aluminum silicate, magnesium silicate, and calcium phosphate. have. It is preferable that microparticles | fine-particles contain silicon from the point that the haze of a film becomes low, and especially silicon dioxide is preferable. It is preferable that the microparticles of silicon dioxide have a primary average particle diameter of 20 nm or less, and have an apparent specific gravity of 70 g / liter or more. It is more preferable that the average diameter of a primary particle is 5-16 nm as small as it can lower the haze of a film. 90-200 g / liter or more is preferable, and, as for apparent specific gravity, 100-200 g / liter or more is more preferable. The larger the apparent specific gravity is, the more preferable it is to be able to form a high concentration dispersion liquid and to improve haze and aggregates.

These microparticles | fine-particles usually form the secondary particle whose average particle diameter is 0.1-3.0 micrometers, and these microparticles | fine-particles exist as aggregate of a primary particle in a film, and form unevenness | corrugation of 0.1-3.0 micrometers in a film surface. 0.2 micrometer or more and 1.5 micrometer or less are preferable, 0.4 micrometer or more and 1.2 micrometer or less are more preferable, and 0.6 micrometer or more and 1.1 micrometer or less are the most preferable. The particle diameters of a primary particle and a secondary particle observed the particle | grains in a film with the scanning electron microscope, and made the diameter of the circle circumscribed to particle | grains the particle diameter. Moreover, 200 particles were observed after changing places, and the average value was made into the average particle diameter.

A commercially available product such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.) . Fine particles of zirconium oxide are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.).

Among these, aerosil 200V and aerosil R972V are fine particles of silicon dioxide having an average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more, while keeping the turbidity of the optical film low, It is particularly preferable because the effect of lowering the friction coefficient is large.

In this invention, in order to obtain the optical film which has a particle | grain with small average particle diameter in a secondary particle, some methods are considered when preparing the dispersion liquid of microparticles | fine-particles. For example, a fine particle dispersion obtained by stirring and mixing a solvent and fine particles is prepared in advance, and the fine particle dispersion is added to a small amount of a cellulose ester or acrylic resin solution separately prepared, stirred and dissolved, and further, a polymer solution for producing a main film (dope solution) ) Can be mixed. This method is a preferable preparation method in that the dispersibility of silicon dioxide fine particles is good and silicon dioxide fine particles are hardly reaggregated. In addition, after adding a small amount of cellulose ester or an acrylic resin to a solvent and stirring and dissolving it, microparticles are added to this, and it disperse | distributes with a disperser, this is made into a fine particle addition liquid, and this fine particle addition liquid is dope liquid by an in-line mixer. There is also a method of mixing sufficiently. Although the present invention is not limited to these methods, the concentration of silicon dioxide in mixing and dispersing silicon dioxide fine particles with a solvent or the like is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, more preferably 15 to 20% % Is most preferable. The higher the dispersion concentration, the lower the liquid turbidity with respect to the addition amount, and the haze and the agglomerate become positive.

0.01-1.0 g per 1 m <2> is preferable, as for the addition amount of the mat agent in a final dope solution, 0.03-0.3g is more preferable, 0.08-0.16g are the most preferable. As addition amount of a mat agent, 0.001-0.4 mass% is preferable with respect to the total amount of resin used for dope solutions, such as a cellulose ester resin and an acrylic resin, 0.001-0.2 mass% is more preferable, 0.01-0.1 mass% More preferred. Moreover, when an optical film is formed in multiple layers, it is preferable not to add to an inner layer but to add only to the surface layer side, and in this case, it is a surface layer with respect to the total amount of resin used for dope solutions, such as a cellulose ester resin and an acrylic resin. As addition amount of the matting agent, 0.001-0.4 mass% is preferable, 0.001-0.2 mass% is more preferable, 0.01-0.1 mass% is more preferable.

The solvent used for the dispersion is preferably a lower alcohol, and examples thereof include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol and butyl alcohol. As solvent other than lower alcohol, it is preferable to use the solvent used at the time of film forming of an optical film.

(Other additives)

In addition to the mat particles, other various additives (for example, a retardation expression agent, a plasticizer, an ultraviolet absorber, a deterioration inhibitor, a release agent, an infrared absorber, a wavelength dispersion regulator, etc.) can be added to the optical film of the present invention, They may be solid or may be oily. That is, it is not specifically limited in the melting point or boiling point. For example, a mixture of an ultraviolet absorbing material of 20 占 폚 or lower and an ultraviolet absorbing material of 20 占 폚 or more, or a mixture of a plasticizer and the like, and is described in, for example, Japanese Patent Laid-Open Publication No. 2001-151901. Further, the infrared absorbing dye is described in, for example, Japanese Patent Application Laid-Open No. 2001-194522. Moreover, although the addition time may be added at any time in a dope manufacturing process, you may add and implement the process of adding and preparing an additive to the last preparation process of a dope preparation process. In addition, the addition amount of each raw material is not specifically limited as long as a function is expressed. Moreover, when an optical film is formed in multiple layers, the additive kind and addition amount of each layer may differ. For example, although it is described in Unexamined-Japanese-Patent No. 2001-151902 etc., these are the techniques known conventionally. Details of these materials are preferably those described in detail on pages 16 to 22 of the Invention Association publication no. (Air No. 2001-1745, published on Mar. 15, 2001 by the Invention Society).

A plasticizer having good compatibility with cellulose esters and acrylic resins is less likely to bleed out, has a low haze, and is effective for the production of a film that realizes a liquid crystal display device excellent in light leakage, front contrast, and brightness.

You may use a plasticizer for the optical film of this invention. Although it does not specifically limit as a plasticizer, A phosphate ester plasticizer, a phthalic ester plasticizer, a polyhydric alcohol ester plasticizer, a polyhydric carboxylic acid ester plasticizer, a glycolate plasticizer, a citric acid ester plasticizer, a fatty acid ester plasticizer, a carboxylic acid Ester plasticizers, polyester oligomer plasticizers, sugar ester plasticizers, ethylenically unsaturated monomer copolymerizing plasticizers, and the like.

Preferably, they are phosphate ester plasticizer, glycolate plasticizer, polyhydric alcohol ester plasticizer, polyester oligomer plasticizer, sugar ester plasticizer, and ethylenically unsaturated monomer copolymerizing plasticizer, More preferably, polyester oligomer type It is a plasticizer, a sugar ester plasticizer, and an ethylenically unsaturated monomer copolymerization plasticizer, More preferably, it is an ethylenically unsaturated monomer copolymerization plasticizer and a sugar ester plasticizer, Especially preferably, it is an ethylenically unsaturated monomer copolymerization plasticizer.

In particular, the polyester oligomer-based plasticizer, the ethylenically unsaturated monomer copolymerized plasticizer, and the sugar ester-based plasticizer have high compatibility with the optical film of the present invention, and have high bleed-out reduction, low haze and low moisture permeability, and change in temperature and humidity. Degradation of the plasticizer over time and deterioration or deformation of the film are less likely to occur, and therefore it can be preferably used in the present invention.

In this invention, 1 type of plasticizers may be used and 2 or more types may be mixed and used for it.

Moreover, you may contain acryl particle | grains in the optical film of this invention. It is described in Japanese Patent Application Laid-open No. H-60-17406, Japanese Patent Laid-Open No. 3-39095 and the like by adding acrylic particles, in particular, a multilayered acrylic granular composite, to improve impact resistance and stress whitening resistance.

In the optical film of this invention, when adding these additives, it is preferable that it is 50 mass% or less with respect to an optical film, and it is preferable that it is 30 mass% or less with respect to an optical film.

&Lt; Properties of optical film &

(Retardation)

In the optical film of the present invention, it is preferable that Re and Rth (defined by the following formulas (I) and (II)) measured at a wavelength of 590 nm satisfy the formulas (III) and (IV).

Formula (I) Re = (nx-ny) × d

Formula (II) Rth = {(nx + ny) / 2-nz} × d

Formula (III) -50 ≤ Re ≤ 50

Equation (IV) Rth ≥ 300

(Wherein nx is a refractive index in the slow axis direction in the film plane of the optical film described above, ny is a refractive index in the fast axis direction in the film surface described above, nz is a refractive index in the film thickness direction of the optical film described above, d Is the thickness (nm) of the above-mentioned optical film)

Moreover, in the optical film of this invention, it is preferable that said formula (III) and (IV) are satisfied in at least 1 point in a film plane, and the said Formula (III) and (IV) in arbitrary points in a film plane It is more preferable that is satisfied.

Re, Rth and Nz in wavelength (lambda) nm can be measured as follows.

Re is measured by injecting light having a wavelength of λ nm in the film normal line direction in KOBRA 21ADH (manufactured by Oji Measurement Instruments Co., Ltd.).

Rth is a retardation measured by injecting light having a wavelength of λnm in a direction inclined at + 40 ° with respect to the film normal direction using the above-described Re, the in-plane slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). Value and the retardation value measured in the total three directions of the retardation value measured by injecting light having a wavelength of λ nm in a direction inclined at -40 ° to the film normal direction using the in-plane slow axis as the inclination axis (rotation axis). It calculates by KOBRA 21ADH on a basis. The assumption of the average refractive index may be a thermoplastic handbook (JOHN WILEY & SONS, INC) and catalog values of various optical films. The thing which does not know the value of an average refractive index in advance can be measured with an Abbe refractometer. The value of the average refractive index of the main optical film is illustrated below: cellulose acylate (1.48), cycloolefin thermoplastic (1.52), polycarbonate (1.59), polymethylmethacrylate (1.49), polystyrene (1.59).

Nz is computed by Formula (VI) based on Re and Rth. Moreover, based on the hypothesis value of the average refractive index and the film thickness, nx, ny, nz can be calculated by KOBRA 21ADH, and Nz can be calculated by the formula (II) from the values of these nx, ny, and nz.

In the measurement of the optical film of this invention, the retardation is measured by making the average refractive index of an optical film 1.48.

Said Re, Rth, and Nz can be adjusted with substitution degree of a cellulose ester, the ratio of a cellulose ester and an acrylic resin, addition of a retardation expression agent, the film thickness of a film, the extending | stretching direction and elongation of a film, etc.

(Thickness of film)

100 micrometers or less are preferable, as for the thickness of the optical film of this invention, 60 micrometers or less are more preferable, 40 micrometers or less are more preferable, 25 micrometers or less are especially preferable. If it is 60 micrometers or less, the environment in which a liquid crystal display device is put, ie, the nonuniformity of the panel accompanying a temperature-humidity change can be made small.

(Moisture permeability of film)

The water vapor transmission rate of a film is measured on 40 degreeC and the conditions of 90% of a relative humidity based on JISZ0208.

The water vapor transmission rate becomes small when the film thickness of a film is thick, and becomes large when the film thickness is thin. Therefore, in samples with different film thicknesses, it is necessary to set the reference to 40 µm and convert it. Conversion of the film thickness can be performed according to the following equation.

Equation: Water vapor transmission rate in terms of 40 µm = Actual water vapor transmission rate × actual film thickness (µm) / 40 (µm).

The water vapor transmission rate of the optical film of this invention is 90 g / m <2> / day or less, It is more preferable that it is 70 g / m <2> / day or less, It is still more preferable that it is 50 g / m <2> / day. When water vapor transmission rate is 90 g / m <2> / day or less, the curvature of the liquid crystal cell and the display nonuniformity at the time of black display after time passage of normal temperature, high humidity, and high temperature, high humidity environment of a liquid crystal display device can be suppressed.

Moreover, the water vapor transmission rate after extending | stretching of this invention is 0.9 times or less compared with before extending | stretching. It is preferable that it is 0.7 times or less, and, as for the water vapor transmission rate after extending | stretching before extending | stretching, it is more preferable that it is 0.6 times or less. There is no special lower limit.

(Haze of film)

It is preferable that all the haze values of the optical film of this invention are 2.00% or less. When the total haze value is 2.00% or less, the transparency of the film is high, and it is effective for improving the contrast ratio and luminance of the liquid crystal display device. The total haze value is more preferably 1.00% or less, still more preferably 0.50% or less, particularly preferably 0.30% or less, and most preferably 0.20% or less. The lower the total haze value is, the better the optical performance is, but in consideration of raw material selection, manufacturing control, and handling property of the roll film, it is preferably 0.01% or more.

It is preferable that the internal haze value of the optical film of this invention is 1.00% or less. By setting the internal haze value to 1.00% or less, the contrast ratio of the liquid crystal display device can be improved, and excellent display characteristics can be realized. The internal haze value is more preferably 0.50% or less, still more preferably 0.20% or less, particularly preferably 0.10% or less, and most preferably 0.05% or less. It is preferable that it is 0.01% or more from a viewpoint of raw material selection, manufacture control, etc.

As the optical film of the present invention, the total haze value is particularly preferably 0.30% or less, and the internal haze value is preferably 0.10% or less.

The total haze value and internal haze value refer to the kind and the amount of the cellulose ester and the acrylic resin of the film material, the amount of the additive selected (particularly, the particle diameter, refractive index, and the amount of the particles of the mat agent), and the film manufacturing conditions (the temperature at the time of stretching). And draw ratio).

In addition, the measurement of haze can be measured according to JISK-6714 by the haze meter (HGM-2DP, Suga tester) at 25 degreeC and 60% of a relative humidity of the film sample of 40 mm x 80 mm of this invention.

(Elastic modulus of film)

It is preferable that the elasticity modulus of the optical film of this invention is 1800-7000 Mpa in the width direction (TD direction).

In the present invention, the elastic modulus in the TD direction is within the above range, and the viewpoint of manufacturing aptitude such as uneven display at the time of black display after elapse of time of high humidity and high temperature and high humidity environment, transportability at the time of film production, end slitability, and poor fracture. Preferred at If the TD modulus is too small, display unevenness occurs during black display after high humidity and high temperature and high humidity environment time elapses, and there is a problem in the aptitude for manufacturing. If the TD modulus is too large, the film workability is inferior. MPa is more preferable, and it is still more preferable that it is 1800-4000 MPa.

Moreover, 1800-4000 Mpa is preferable and, as for the elasticity modulus of (MD direction) of the conveyance direction of the optical film of this invention, it is more preferable that it is 1800-3000 Mpa.

Here, the conveyance direction (length direction) of a film is a conveyance direction (MD direction) at the time of film manufacture, and a direction (TD direction) perpendicular | vertical to the conveyance direction at the time of film manufacture with a width direction.

The elastic modulus of the film can be adjusted by the type and amount of the cellulose ester or acrylic resin of the film material, the selection of the additives (particularly, the particle size of the particles of the mat agent, the refractive index, the amount of addition), and furthermore, the film production conditions (elongation ratio, etc.). have.

Elastic modulus can be calculated | required using the universal tensile tester "STM T50BP" by Toyo Baldwin Co., Ltd., for example.

In the present invention, a 10 mm x 150 mm (TD x MD) sample is humidified at 25 ° C, relative humidity of 60% for 2 hours, and the atmosphere of 60% relative humidity at 25 ° C using a universal tensile tester STM T50BP manufactured by Toyo Baldwin. The stress of 0.1% elongation time point and 0.5% elongation is measured by the extending | stretching process to MD direction by 50 mm of initial sample lengths and 10% / min.

In the optical film of this invention, when extending | stretching to either a conveyance direction (MD direction) or the width direction (TD direction) of a film, the elasticity modulus after extending | stretching becomes 1.5 times or more compared with the elasticity modulus when it is not extending | stretching. The ratio of this elastic modulus becomes like this. More preferably, it is 1.6 times or more. It is preferable that an upper limit is 2.0 times or less.

(Glass transition temperature Tg)

100-200 degreeC is preferable and, as for the glass transition temperature Tg of the optical film of this invention from a viewpoint of manufacture suitability and heat resistance, 100-150 degreeC is more preferable.

The glass transition temperature is the average value of the temperature at which the baseline originating from the glass transition of the film starts to change when measured at a temperature rising rate of 10 ° C./minute using a differential scanning calorimeter (DSC) and the temperature returns to the baseline again. It can be obtained as

In addition, the measurement of glass transition temperature can also be calculated | required using the following dynamic viscoelasticity measuring apparatus. Dynamic viscoelasticity measuring device (Vibron: DVA-225 (manufactured by Haiti Metrology Control Co., Ltd.)) after humidifying 5 mm x 30 mm of the film sample of this invention at 25 degreeC, 60% of a relative humidity for 2 hours or more. The distance between the grips was 20 mm, the temperature increase rate was 2 ° C./min, the measurement temperature range was 30 ° C. to 250 ° C., and the frequency was 1 Hz, and the storage elastic modulus and the horizontal axis were taken as temperature (° C.) on the vertical axis. The intersection of the straight line 1 and the straight line 2 when a straight line 1 is drawn in the solid region and a straight line 2 is drawn in the glass transition region is caused to drastically decrease the storage elastic modulus seen when the storage modulus transitions from the solid region to the glass transition region. The storage elastic modulus decreases rapidly at the time, and the temperature at which the film starts to soften, and the temperature at which the film starts to transition to the glass transition region, is defined as the glass transition temperature Tg (dynamic viscoelasticity).

(Equilibrium moisture content of film)

The water content (equilibrium water content) of the optical film of the present invention is 25 ° C. and relative humidity regardless of the film thickness, so as not to impair adhesion with water-soluble thermoplastics such as polyvinyl alcohol when used as a protective film of a polarizing plate. It is preferable that the moisture content in 80% is 0-4 mass%. It is more preferable that it is 0.1-2.5 mass%, and it is still more preferable that it is 0.5-1.5 mass%. When the equilibrium moisture content is 4% by mass or less, the dependence due to the humidity change of the retardation does not become too large, and the display unevenness at the time of black display after elapse of time in the room temperature, high humidity, and high temperature and high humidity environment of the liquid crystal display device is suppressed. Also preferred.

The measurement method of the moisture content measured 7 mm x 35 mm of film samples by the Karl Fischer method with a moisture meter, sample drying apparatus "CA-03", and "VA-05" (all are manufactured by Mitsubishi Chemical Corporation). It can calculate by dividing the moisture content g by the sample mass g.

(Dimension of film)

The dimensional stability of the optical film of this invention is the dimensional change rate of (high humidity) when it is left to stand on 60 degreeC and the conditions of 90% of relative humidity for 24 hours, and 80 degreeC of DRY environment (5% or less of relative humidity). When it is left to stand on conditions for 24 hours, it is preferable that all the dimensional change rates of (high temperature) are 0.5% or less. More preferably, it is 0.3% or less, More preferably, it is 0.15% or less.

(Optical elastic modulus)

When the optical film of this invention is used as a protective film for polarizing plates, birefringence (Re, Rth) may change by stress etc. by shrinkage of a polarizer. Although the birefringence change accompanying such a stress can be measured as a photoelastic coefficient, it is preferable that the range is 15 Br or less, It is more preferable that it is -3-12 Br, It is still more preferable that it is 0-11 Br.

[Method of Manufacturing Optical Film]

The preferable manufacturing method of the optical film of this invention is demonstrated. As an example of a preferable manufacturing method, the thermoplastic resin and the moisture permeability-reducing compound are flexible, and the process of forming a polymer film is carried out on a support body,

The molecular weight of the above-mentioned water vapor transmission rate reduction compound is 200 or more,

The manufacturing method by which the water vapor transmission rate reduction compound mentioned above satisfy | fills following formula (1) is mentioned.

Equation (1) A / B ≤ 0.9

(In formula (1), A shows the water vapor transmission rate of the optical film at the time of adding 10 mass% of this water vapor transmission rate reduction compound with respect to the mass with the above-mentioned thermoplastic resin, B contains the above-mentioned thermoplastic resin, and also has a water vapor transmission rate reduction compound. The water vapor transmission rate of an optical film in the case of not adding (yield) is shown, except that the water vapor transmission rate is a value obtained by converting the value after the lapse of 24 hours at 40 ° C. and 90% of the relative humidity by a method of JIS Z 0208 to a 40 μm film thickness.)

As a polymer film used for extending | stretching, 100-200 degreeC is preferable and, as for the glass transition temperature Tg of the unstretched polymer film after drying, 100-150 degreeC is more preferable.

Here, with the polymer film (dry film) after drying, the residual solvent amount in a film is 3.0 mass% or less, Preferably it is 1.0 mass% or less, More preferably, it is 0.5 mass% or less, More preferably, it is 0.3 mass% or less, Especially preferably, Refers to a polymer film that is 0.2% by mass or less.

As the film forming method of the polymer film described above, manufacturing methods such as the inflation method, the T-die method, the calendar method, the cutting method, the casting method, the emulsion method, and the hot pressing method can be used. Solution film forming by the casting method is preferable from the viewpoint of suppressing optical defects such as the like.

The optical film of this invention may be manufactured using the solution casting method, and may be manufactured using the melt casting method.

In the case of the solution casting method, the above-described polymer film is formed by casting a polymer solution (dope) containing the above-mentioned thermoplastic resin, the above-mentioned moisture-permeability-reducing compound, and a solvent on a support.

(menstruum)

The solvent useful for forming the dope can be used without limitation so long as it dissolves the above-mentioned thermoplastic resin, the above-mentioned moisture-permeability-reducing compound, and other additives simultaneously.

In the present invention, any of a chlorine-based solvent containing chlorine-based organic solvent as a main solvent and a non-chlorine-based solvent containing no chlorine-based organic solvent can be used as the organic solvent. You may mix and use two or more types of organic solvents.

In preparing dope, a chlorine organic solvent is used preferably as a main solvent. In the present invention, as long as the object can be achieved within the range in which the above-mentioned thermoplastic resin can be dissolved and cast and film forming, the kind of the chlorine-based organic solvent is not particularly limited. These chlorine organic solvents are preferably dichloromethane and chloroform. In particular, dichloromethane is preferable. In addition, it is not particularly problematic to mix an organic solvent other than the chlorinated organic solvent. In that case, it is necessary to use at least 50 mass% of dichloromethane in the organic solvent whole quantity. Other organic solvents used in combination with the chlorinated organic solvent in the present invention are described below. That is, preferred examples of the other organic solvent include a solvent selected from esters, ketones, ethers, alcohols and hydrocarbons having 3 to 12 carbon atoms. The esters, ketones, ethers and alcohols may have a cyclic structure. Compounds having two or more functional groups (i.e., -O-, -CO- and -COO-) of ester, ketone and ether can also be used as the solvent, and even if they contain other functional groups such as alcoholic hydroxyl groups do. In the case of the solvent which has two or more types of functional groups, the carbon atom number should just be in the prescribed range of the compound which has any functional group.

Examples of the esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate. Examples of the ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phentol Etc. can be mentioned. 2-ethoxy ethyl acetate, 2-methoxy ethanol, 2-butoxy ethanol, etc. are mentioned as an example of the organic solvent which has two or more types of functional groups.

Moreover, as alcohol used together with a chlorine organic solvent, Preferably, it may be linear, may have a branch, may be cyclic, and it is especially preferable that it is a saturated aliphatic hydrocarbon. The hydroxyl group of alcohol may be any of the 1st class-3rd class. Examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, a fluorinated alcohol is also used. For example, 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3- tetrafluoro-1-propanol, etc. are mentioned. The hydrocarbons may be linear, branched or cyclic. Both aromatic and aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene.

As the other solvent, for example, the solvent described in JP-A-2007-140497 can be used.

(Preparation of dope)

Dope can be prepared by the general method which consists of processing at temperature (normal temperature or high temperature) of 0 degreeC or more. Preparation of the dope of this invention can be performed using the preparation method and apparatus of the dope in a normal solvent casting method. In addition, in the general method, halogenated hydrocarbons (particularly dichloromethane) and alcohols (particularly methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-) are used as organic solvents. Pentanol, 2-methyl-2-butanol and cyclohexanol).

It is preferable to adjust so that the total amount of the above-mentioned thermoplastic resin may be contained 10-40 mass% in the obtained polymer solution.

It is further more preferable that the quantity of the above-mentioned thermoplastic resin is 10-30 mass%. In the organic solvent (main solvent), you may add the arbitrary additive mentioned later.

A solution can be prepared by stirring the above-mentioned thermoplastic resin and organic solvent at normal temperature (0-40 degreeC). The high concentration solution may be stirred under pressurized and heated conditions. Specifically, the above-mentioned thermoplastic resin and the organic solvent are put in a pressurized container and sealed, and the mixture is stirred while heating to a temperature not lower than the boiling point at normal temperature of the solvent and the solvent does not boil under pressure.

Heating temperature is 40 degreeC or more normally, Preferably it is 60-200 degreeC, More preferably, it is 80-110 degreeC.

Each component may be preliminarily mixed and then put in a container. It is also permissible to sequentially inject the solution into a container. The vessel needs to be configured to be able to stir. The vessel can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may use the vapor pressure raise of a solvent by heating. Alternatively, after sealing the container, each component may be added under pressure.

When heating, it is preferable to heat from the exterior of a container. For example, a jacket type heating device can be used. It is also possible to heat the entire container by forming a plate heater on the outside of the container and circulating the liquid through the pipe.

It is preferable to form stirring vanes inside the container and stir using this. It is preferable that the stirring blade is a length reaching near the wall of the container. In order to update the liquid film of a container wall, it is preferable to form a deodorant blade at the end of the stirring blade.

Instrumentation such as pressure gauge, thermometer, etc. may be installed in the container. Each component is dissolved in a solvent in a container. The prepared dope is taken out of the container after cooling or taken out, and then cooled using a heat exchanger or the like.

(Production of film-solution film formation method-)

Next, the method to manufacture the optical film of this invention using the dope obtained above is demonstrated.

1 is a schematic view showing a film production line 20. However, this invention is not limited to the film manufacturing line shown in FIG. The film production line 20 includes a stock tank 21, a filtration device 30, a flexible die 31, a flexible band 34, a tenter-type dryer 35, and the like placed over the rotating rollers 32 and 33. It is provided. Moreover, the edge cutting device 40, the drying chamber 41, the cooling chamber 42, the winding chamber 43, etc. are arrange | positioned.

The stirrer 61 which rotates by the motor 60 is attached to the stock tank 21. The stock tank 21 is connected to the flexible die 31 via the pump 62 and the filtration device 30.

Although the width | variety of the casting die 31 is not specifically limited, It is preferable that it is 1.1 times-2.0 times the width of the film used as a final product.

Below the casting die 31, the casting band 34 which is spread over the rotating rollers 32 and 33 is formed. The rotary rollers 32 and 33 rotate by a drive device not shown, and with this rotation, the flexible band 34 travels without permission.

Moreover, in order to make the surface temperature of the flexible band 34 into a predetermined value, it is preferable that the heat transfer medium circulation apparatus 63 is attached to the rotating rollers 32 and 33. It is preferable that the surface temperature of the flexible band 34 can be adjusted to -20 degreeC-40 degreeC.

Although the width | variety of the flexible band 34 is not specifically limited, It is preferable to use the thing of 1.1 times-2.0 times the range of the flexible width of the dope 22. The length is preferably 20 m to 200 m, the film thickness is 0.5 mm to 2.5 mm, and the surface roughness is preferably polished to 0.05 µm or less. It is preferable that the flexible band 34 is made of stainless steel, and more preferably made of SUS316 so as to have sufficient corrosion resistance and strength. Moreover, it is preferable to use the thing in which the film thickness nonuniformity of the whole flexible band 34 is 0.5% or less.

In addition, the rotating rollers 32 and 33 can also be used directly as a support body.

The flexible die 31, the flexible band 34, and the like are housed in the flexible chamber 64. The casting chamber 64 is provided with a temperature controller 65 for maintaining the internal temperature at a predetermined value, and a condenser 66 for condensing and recovering the volatilized organic solvent. And the collection | recovery apparatus 67 for collect | recovering the condensation liquefied organic solvent is formed in the exterior of the casting chamber 64. Moreover, it is preferable that the pressure reduction chamber 68 for pressure-controlling the back part of the flexible bead formed over the flexible band 34 in the casting die 31 is arrange | positioned, and this embodiment also uses this.

In order to evaporate the solvent in the casting film 69, the tuyere 70, 71, 72 is formed near the peripheral surface of the casting band 34.

The conveying part 80 is provided with the blower 81, and the edge cutting device 40 downstream of the tenter type | mold dryer 35 cut | disconnects finely the debris of the side edge part (referred to as an edge) of the film 82 cut out. The crusher 90 for processing is connected.

The drying chamber 41 is equipped with many rollers 91, and is equipped with the adsorption | recovery recovery apparatus 92 for adsorption-recovery of the solvent gas which evaporated and generate | occur | produced. Downstream of the cooling chamber 42, a forced static elimination device (antistatic bar) 93 for adjusting the large voltage of the film 82 to be within a predetermined range (for example, -3 kPa to +3 kPa) is formed. It is. In addition, in this embodiment, the knurling provision roller 94 for giving a knurling to both edges of the film 82 by embossing is formed suitably downstream of the forced static elimination apparatus 93. Moreover, the winding roller 95 for winding up the film 82 and the press roller 96 for controlling the tension at the time of winding are provided in the inside of the winding chamber 43.

Next, an example of the method of manufacturing the film 82 using the above-mentioned film production line 20 is demonstrated below.

The dope 22 is always uniformized by the rotation of the stirrer 61. In the dope 22, additives, such as a retardation expression agent, a plasticizer, and a ultraviolet absorber, can also be mixed also at the time of this stirring.

After the dope 22 is sent to the filtration apparatus 30 by the pump 62 and filtered here, it is cast on the casting band 34 in the casting die 31.

A flexible bead is formed in the flexible die 31 over the flexible band 34, and a flexible film 69 is formed on the flexible band 34. It is preferable that the temperature of the dope 22 at the time of casting | flow_spread is -10 degreeC-57 degreeC.

The dope 22 from the casting die 31 forms a casting bead, and is cast on the casting band 34.

The flexible membrane 69 moves with the movement of the flexible band 34.

Next, the flexible membrane 69 is continuously conveyed to the point where the tuyere 73 is arrange | positioned at the upper part. Dry air is blown toward the casting film 69 from the nozzle of the tuyeres 73.

After the solvent evaporates as a result of evaporation of the flexible film 69, the flexible film 69 is dehydrated from the flexible band 34 while being supported by the deodorizing roller 75 as the wet film 74. do. It is preferable that the amount of residual solvent at the time of deodorization is 20 mass%-250 mass% on a solid content basis.

After that, the conveyance part 80 in which many rollers are formed is conveyed, and the wet film 74 is conveyed to the tenter type dryer 35. In the conveyance part 80, drying of the wet film 74 is advanced by blowing the drying wind of desired temperature from the blower 81. FIG. At this time, it is preferable that the temperature of a drying wind is 20 degreeC-250 degreeC.

It is preferable that the wet film 74 is extended | stretched in any direction of a conveyance direction (MD direction) and the orthogonal width direction (TD direction). By extending | stretching to a conveyance direction and the width direction, a water vapor transmission rate can be reduced. Moreover, the nonuniformity which generate | occur | produced at the time of drying in a support body, and deprivation can be reduced, and the favorable surface shape can be obtained in a film surface.

The wet film 74 conveyed to the tenter type dryer 35 is dried while its both ends are gripped and conveyed by a clip. Stretching in the width direction can be performed using the tenter type dryer 35 at this time.

In addition, it is preferable to divide the inside of the tenter type dryer into the temperature zone, and to adjust the drying conditions suitably for each division.

In this way, the wet film 74 can be stretched in the width direction by the transfer unit 80 and / or the tenter type dryer 35.

Moreover, you may perform extending | stretching to a conveyance direction, and give a wet tension to the wet film 74 in a conveyance direction by carrying out faster than the rotational speed of the roller of a downstream side by the conveyance part 80 in the conveyance direction. can do.

Here, in the transfer part 80 and / or the tenter type dryer 35, the wet film 74 is unstretched and dried, and the residual solvent amount in a film is 3.0 mass% or less, Preferably it is 1.0 mass% or less, More Preferably it is 0.5 mass% or less, More preferably, you may extend | stretch after setting it as the dry film which is 0.3 mass% or less, Especially preferably, it is 0.2 mass% or less.

In addition, when extending | stretching a dry film, you may perform extending | stretching further, after manufacturing a dry film and winding up once, unstretched.

Although a dry film or a wet film may be sufficient as the polymer film used for extending | stretching, it is more preferable that it is a wet film.

It is preferable that the draw ratio of a width direction (TD direction) is 3.0-6.0 times. It is preferable that the draw ratio of a conveyance direction (MD direction) is 3.0-6.0 times. Moreover, since tension by conveyance is added even if it does not extend | stretch draw tension intentionally in a conveyance direction, the film extended | stretched by the magnification of about 1.01 to 1.1 times may be obtained as a result.

It is preferable to make the temperature at the time of extending | stretching into the temperature range of Tg +/- 30 degreeC with respect to the glass transition temperature Tg of the unstretched polymer film after drying. Here, the glass transition temperature of the unstretched polymer film after drying is the glass transition temperature of the thermoplastic resin mentioned above. Stretching in this temperature range has good handling aptitude of the film, and can produce a desired optical film without breaking the polymer film. By extending | stretching above (Tg-30 degreeC), break of a film can be prevented and the dispersion | variation of Rth in a film can be suppressed. Moreover, extending | stretching below (Tg + 30 degreeC) can prevent extending | stretching by the self weight of a film, and can suppress the dispersion | variation of Rth in a film. Moreover, the increase of the total haze and internal haze by phase separation in a film can be suppressed.

Thus, after extending | stretching the wet film 74, the extending | stretching process may be performed by the drying process which passes the conveyance part 80 and the tenter type dryer 35, and after drying the wet film 74, after winding up, it may be performed. do.

When the film is manufactured by unstretching, the casting conditions of the present invention are preferably carried out under the condition that the film thickness of the film is 10 to 200 µm, more preferably 20 to 150 µm, and further 30 to 120 µm. It is preferable to set it as conditions which become 40-100 micrometers.

When it exists in this range, the film thickness of the film after extending | stretching can be made small, and the retardation change after elapse of time in humidity change, high temperature, and high temperature, high humidity environment becomes small, and it is possible to manufacture an inexpensive film with few resins to use further. It is preferable because it can.

The wet film 74 is dried to a predetermined residual solvent amount by the tenter dryer 35 and then sent out to the downstream side as the film 82. Both side ends of the film 82 are cut at both edges by the edge cutting device 40. The cut | disconnected side end part is sent to the crusher 90 by the cutter blower which is not shown in figure. The crusher 90 causes the film side ends to be crushed into chips. Since this chip is reused for dope preparation, this method is effective in terms of cost. In addition, although the process of cutting | disconnecting this film both side end parts may be abbreviate | omitted, it is preferable to implement in any process from the casting process mentioned above to the process of winding up the said film.

The film 82 whose both ends are cut off is sent to the drying chamber 41, and is further dried. Although the temperature in the drying chamber 41 is not specifically limited, It is preferable that it is the range of 50 degreeC-160 degreeC. In the drying chamber 41, the film 82 is conveyed while being wound on the roller 91, and the solvent gas generated by evaporation is adsorbed and recovered by the adsorption recovery apparatus 92. The air from which the solvent component has been removed is blown again as dry air inside the drying chamber 41. In addition, the drying chamber 41 is more preferably divided into a plurality of sections in order to change the drying temperature.

The film 82 is cooled to approximately room temperature in the cooling chamber 42. In addition, a humidity chamber (not shown) may be provided between the drying chamber 41 and the cooling chamber 42, and it is preferable that air adjusted to a desired humidity and temperature is injected to the film 82 in the humidity chamber. Do. Thereby, generation | occurrence | production of the curl of the film 82 and generation | occurrence | production of the winding fault at the time of winding up can be suppressed.

In addition, by the forced static elimination device (antistatic bar) 93, the large voltage while the film 82 is being conveyed is within a predetermined range (for example, -3 kPa to +3 kPa). Moreover, it is preferable to form a knurling provision roller 94, and to provide knurling to both edges of the film 82 by embossing.

Finally, the film 82 is wound up by the winding roller 95 in the winding chamber 43. At this time, it is preferable to wind up, providing the desired tension with the press roller 96. Moreover, as for tension, it is more preferable to change gradually from the start of winding to the end. It is preferable to make the film 82 to be wound into at least 100 m or more in the longitudinal direction (flexibility direction). Moreover, it is preferable that the width | variety of the film 82 is 600 mm or more, It is more preferable that it is 1100 mm or more and 2900 mm or less, More preferably, it is 1800 mm or more and 2500 mm or less.

In the solution film forming method of the present invention, when the dope is softened, two or more types of dope may be co-laminated shared lead or sequential laminated co-lead. Further, both shared lines may be combined. When performing simultaneous lamination sharing, a flexible die with a feed block may be used, or a multi-manifold flexible die may be used. It is preferable that at least one of the thickness of the layer of an air surface side, and the thickness of the layer of a support body side is 0.5%-30% of the film thickness of the whole film of the film which consists of a multilayer by a covalent lead. In addition, in the case of performing simultaneous lamination sharing, it is preferable that the high viscosity dope is wrapped by the low viscosity dope when the dope is cast from the die slit to the support. In addition, in the case of performing simultaneous lamination sharing, it is preferable that, among the flexible beads formed from the die slit over the support, the dope in contact with the external system has a larger alcohol composition ratio than the internal dope.

Structures such as casting die, pressure reduction chamber, support body, covalent lead, peeling method, stretching, drying conditions of each step, handling method, curl, winding method after planarity correction, solvent recovery method, film recovery method It is described in detail in paragraphs [0617] to [0889] of 2005-104148.

Moreover, in the above, an example of the manufacturing method of the optical film of this invention was demonstrated to the example which made dope cast on a band, You may make dope cast on a drum.

(Surface treatment)

The optical film can achieve the improvement of the adhesion of an optical film and another layer (for example, a polarizer, a undercoat, and a back layer) by subjecting to surface treatment as needed. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment herein may be a low temperature plasma generated under a low pressure gas of 10 ⁻³ to 20 Torr, and also preferably a plasma treatment under atmospheric pressure. The plasma-excited gas refers to a gas that is plasma excited under the above conditions, and examples thereof include argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, and freons such as tetrafluoromethane, and mixtures thereof. About these, the details are described in detail in 30-32 pages in the invention association publication (an air service number 2001-1745, published March 15, 2001, invention association), and can be used conveniently in this invention. .

(Functional layer)

Moreover, the optical film of this invention may laminate | stack a functional layer with a film thickness of 0.1-20 micrometers on at least one surface. Examples of the functional layer include a hard coat layer, an antireflection layer (a layer having a refractive index such as a low refractive index layer, a medium refractive index layer, and a high refractive index layer), an antiglare layer, an antistatic layer, an ultraviolet absorbing layer, a moisture permeability reducing layer, and the like.

One layer may be sufficient as the above-mentioned functional layer, and multiple layers may be formed. Although the lamination method of the functional layer mentioned above is not specifically limited, It apply | coats and forms on the covalent edge of a thermoplastic resin and the optical film containing the above-mentioned water vapor transmission rate reduction compound, or on the optical film containing a thermoplastic resin and the above-mentioned water vapor transmission rate reduction compound, It is preferable to form.

When forming a functional layer by application | coating and drying, it is preferable to use a polymeric polyfunctional monomer as a binder, It is more preferable to use a photopolymerizable polyfunctional monomer, It is more preferable to use two or more (meth) acryloyl groups It is especially preferable to use the coating liquid containing the monomer which has.

Specific examples of the monomer having two or more (meth) acryloyl groups include alkylene glycols such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, and propylene glycol di (meth) acrylate. (Meth) acrylic acid diesters;

(Meth) acrylic of polyoxyalkylene glycols such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate Acid diesters;

(Meth) acrylate diesters of polyhydric alcohols such as pentaerythritol di (meth) acrylate;

(Meth) acrylate of an ethylene oxide or propylene oxide adduct such as 2,2-bis {4- (acryloxy diethoxy) phenyl} propane and 2-2-bis {4- (acryloxypolypropoxy) Acrylic acid diesters;

And the like.

Furthermore, epoxy (meth) acrylates, urethane (meth) acrylates, and polyester (meth) acrylates are also preferably used as the photopolymerizable polyfunctional monomer.

Especially, ester of polyhydric alcohol and (meth) acrylic acid is preferable.

More preferably, the polyfunctional monomer which has three or more (meth) acryloyl groups in 1 molecule is preferable. For example, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, propylene oxide modified Trimethylolpropane tri (meth) acrylate, ethylene oxide modified phosphate tri (meth) acrylate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, Caprolactone modified tris (acryloxyethyl) isocyanurate etc. are mentioned.

In addition, resins having three or more (meth) acryloyl groups, for example, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, and polybutadiene resins And oligomers or prepolymers such as polyfunctional compounds such as polythiolpolyene resins and polyhydric alcohols.

As another polyfunctional monomer mentioned above, the dendrimer of Unexamined-Japanese-Patent No. 2005-76005 and 2005-36105 can also be used, for example.

Moreover, as other polyfunctional monomer, the ester of polyhydric alcohol and (meth) acrylic acid, the amide of the isocyanate containing polyhydric alcohol and several (meth) acryloyl groups are also used preferably. Polyhydric alcohol means bivalent or more alcohol. Although it does not restrict | limit especially as polyhydric alcohol, Aliphatic alcohol is preferable and the alcohol which has a cyclic aliphatic hydrocarbon group is especially preferable.

As an alicyclic alcohol, a monocyclic type, such as a cyclopentyl group and a cyclohexyl group, may be sufficient as a polycyclic type, but a polycyclic type is more preferable. As the polycyclic alcohol, it is particularly preferable to use polyhydric alcohols having a norbornyl group and polyhydric alcohols having an adamantyl group as described in JP 2005-60425 A.

The polyfunctional monomer may use two or more types together. Polymerization of the monomer having these ethylenically unsaturated groups can be carried out by irradiation of ionizing radiation or heating in the presence of an optical radical initiator or a thermal radical initiator.

It is preferable to use a photoinitiator for the polymerization reaction of a photopolymerizable polyfunctional monomer. As a photoinitiator, an optical radical polymerization initiator and a photocationic polymerization initiator are preferable, and an optical radical polymerization initiator is especially preferable.

Moreover, it is also preferable to use together the monomer which has two or more (meth) acryloyl groups mentioned above, and the monomer which has one (meth) acryloyl group.

As for the monomer which has one (meth) acryloyl group, ester of monohydric alcohol and (meth) acrylic acid is preferable.

The monohydric alcohol described above may be aliphatic or aromatic as long as it has a hydrophobic skeleton. As an aliphatic alcohol, monocyclic type, such as a cyclopentyl group and a cyclohexyl group, may be sufficient, and polycyclic type which has a norbornyl group and an adamantyl group may be sufficient as it.

As (meth) acrylic acid, acrylic acid and methacrylic acid are preferable.

As for the thickness of the functional layer mentioned above, it is more preferable that it is 0.01-100 micrometers, and it is especially preferable that it is 0.02-50 micrometers. Moreover, as a functional layer which reduces water vapor transmission rate, it is more preferable that it is 0.1-20 micrometers in thickness.

When using the functional layer which reduces the water vapor transmission rate mentioned above, it is preferable that C / D becomes 0.9 or less for the water vapor transmission rate (C) of the optical film which laminated | stacked the functional layer, and the water vapor transmission rate (D) of the optical film without lamination | stacking. . It is more preferable that it is 0.85 or less, and it is still more preferable that it is 0.8 or less.

Other functional layers

The optical film of this invention may have another optically anisotropic layer, and a cross-sectional schematic diagram is shown in FIG. 2 as an example of the preferable aspect.

The optical film 10 shown in FIG. 2 has the transparent support body 14, the optically anisotropic layer 12, and the support body 16, and the optically anisotropic layer 12 is a layer which produces a phase difference, The film | membrane which has a constant phase difference is The optically anisotropic layer formed uniformly in surface may be sufficient, and the pattern optically anisotropic layer in which the area | region different from slow axis, phase difference, etc. mutually differ may be regularly arrange | positioned in surface.

As an optically anisotropic layer in which the film having a constant phase difference described above is formed uniformly in the plane, a λ / 4 film is preferable, and for a specific embodiment of an optical film in which the λ / 4 film is an optically anisotropic layer, JP 2012-098721 A, The optically anisotropic layer and optical film of Unexamined-Japanese-Patent No. 2012-103689, Unexamined-Japanese-Patent No. 2012-177894 can be used suitably.

The optical film which uses (lambda) / 4 film as an optically anisotropic layer can be used for a brightness improving board, a 3D liquid crystal display device, etc., and is especially useful as a member of an active 3D liquid crystal display device.

Next, a patterned optically anisotropic layer is demonstrated.

The patterned optically anisotropic layer is an optically anisotropic layer in which the first and second phase difference regions are equally and symmetrically arranged in the image display device. It is preferable that the first and second retardation regions each have an in-plane slow axis orthogonal to each other.

The in-plane slow axes of the first and second retardation regions are orthogonal to each other, and the in-plane retardation Re is preferably a pattern λ / 4 layer having λ / 4. When the patterned optically anisotropic layer of this aspect is combined with a polarizing film, the light passing through each of the first and second retardation regions becomes circularly polarized states in the opposite directions to form circularly polarized images for the right eye and the left eye, respectively.

About the specific aspect of the optical film which makes the above-mentioned pattern (lambda) / 4 layer an optically anisotropic layer, the optically anisotropic layer of Unexamined-Japanese-Patent No. 4825934, 4887463, and an optical film can be used suitably.

The above-mentioned optical film is useful as a member of a 3D liquid crystal display device, especially a passive 3D liquid crystal display device. In this aspect, the polarized light image that has passed through each of the first and second retardation areas is recognized as an image for the right eye or the left eye through polarized glasses or the like. Therefore, it is preferable that the first and second retardation regions have a shape equal to each other so that the left and right images are not uneven, and each arrangement is preferably equal and symmetrical.

The above-mentioned pattern optically anisotropic layer is not limited to the said aspect, For example, one in-plane retardation of a 1st and 2nd phase difference region is (lambda) / 4, and the other in-plane retardation is 3 (lambda) / A display pixel area of 4 can be used. In addition, a phase difference region in which one in-plane retardation of the first and second retardation regions is λ / 2 and the other in-plane retardation is zero may be used.

The optical film of this invention can be used also as an optical compensation film of a liquid crystal display device. The liquid crystal cell in which a liquid crystal display device carries a liquid crystal between two electrode substrates, two polarizing elements arrange | positioned at the both sides, and at least 1 optical film of this invention between this liquid crystal cell and this polarizing element are optical compensation films It is more preferable that it is a structure arrange | positioned as. As these liquid crystal display devices, the liquid crystal display device of TN, IPS, FLC, AFLC, OCB, STN, ECB, VA, and HAN mode is preferable, and the liquid crystal display device of TN, OCB, IPS, and VA mode is more preferable, The liquid crystal display device of VA mode is more preferable.

In that case, you may provide various functional layers to the optical film of this invention. Examples of the functional layer include an antistatic layer, a cured resin layer (transparent hard coat layer), an antireflection layer, an easy adhesion layer, an antiglare layer, an optically anisotropic layer, an alignment layer, a liquid crystal layer, and the like. As these functional layers and its material, surfactant, a lubricating agent, a mat agent, an antistatic layer, a hard-coat layer, etc. are mentioned, Invention Association Publication (Publication No. 2001-1745, published March 15, 2001, Invention Association) ) Is described in detail on pages 32 to 45, and can be preferably used in the present invention.

[Polarizer]

The polarizing plate of this invention contains at least 1 optical film of this invention as a protective film of a polarizer, It is characterized by the above-mentioned.

The optical film of the present invention can be used as a protective film for a polarizing plate. In this case, it can serve as the optical compensation film of a liquid crystal display device, and the protective film for polarizing plates. When used as a protective film for a polarizing plate, the production method of the polarizing plate is not particularly limited and can be produced by a general method. Alkali treatment of the obtained optical film and the polyvinyl alcohol film are immersed and extended in the iodine solution, and there exists a method of bonding together using the fully saponified polyvinyl alcohol aqueous solution on both sides of the polarizer manufactured. Instead of alkali treatment, you may perform the easily bonding process as described in Unexamined-Japanese-Patent No. 6-94915 and Unexamined-Japanese-Patent No. 6-118232. Moreover, you may perform the surface treatment as mentioned above.

Examples of the adhesive used for bonding the protective film treated surface and the polarizer include polyvinyl alcohol based adhesives such as polyvinyl alcohol and polyvinyl butyral and vinyl based latex such as butyl acrylate have.

A polarizing plate is comprised from the polarizer and the protective film which protects both surfaces, and is further comprised by bonding a protective film to one surface of this polarizing plate, and a separate film to the opposite surface. A protective film and a separate film are used for the purpose of protecting a polarizing plate at the time of a polarizing plate shipment, a product inspection, etc. In this case, a protective film is bonded for the purpose of protecting the surface of a polarizing plate, and is used for the opposite surface side of the surface which bonds a polarizing plate to a liquid crystal plate. Moreover, a separator film is used for the purpose of covering the adhesive layer bonded to a liquid crystal plate, and is used for the surface side which a polarizing plate bonds to a liquid crystal plate.

Although the board | substrate containing a liquid crystal cell is normally arrange | positioned between two polarizing plates in a liquid crystal display device, although the protective film for polarizing plates which applied the optical film of this invention can be used as a protective film of any one of two polarizing plates, It is preferable to be used as a protective film arrange | positioned at the liquid crystal cell side with respect to a polarizer among long protective films.

(Optical compensation film)

The optical film of this invention can be used for various uses, and when used as an optical compensation film of a liquid crystal display device, it is especially effective. In addition, an optical compensation film is generally used for a liquid crystal display device, shows the optical material which compensates retardation, and has the same meaning as a retardation plate, an optical compensation sheet, etc. An optical compensation film has birefringence and is used for the purpose of removing the coloring of the display screen of a liquid crystal display device, or improving a viewing angle characteristic.

The optical film of this invention may be itself an optical compensation film, may be used as a support body of an optical compensation film, and may form an optically anisotropic layer on it. The optically anisotropic layer is not limited to the optical performance of the liquid crystal cell of the liquid crystal display device in which the optical film of this invention is used, or a drive system, and can use together the optically anisotropic layer required as an optical compensation film. As an optically anisotropic layer used together, you may form with the composition containing a liquid crystalline compound, and you may form with the thermoplastic film which has birefringence.

When the polarizing plate protective film of this invention is an optical compensation film, it is preferable to bond together the bonding method with respect to the polarizer so that the transmission axis of a polarizer and the slow axis of the polarizing plate protective film of this invention may become substantially parallel. In the liquid crystal display device of this invention, it is preferable that the transmission axis of a polarizing plate and the slow axis of the polarizing plate protective film of this invention are substantially parallel. Here, substantially parallel means that the shift | offset | difference of the direction of the principal refractive index nx of the polarizing plate protective film of this invention, and the direction of the transmission axis of a polarizing plate is 5 degrees or less, and it is 1 degrees or less, Preferably it is 0.5 degrees or less desirable. If the deviation is larger than 1 °, the polarization degree performance under the polarizing plate cross nicol degrades and light leakage occurs, which is not preferable.

<Performance of Polarizer>

The orthogonal transmittance CT of the polarizing plate was measured using UV3100PC (made by Shimadzu Corporation). As a measurement, it measured in the range of 380 nm-780 nm, and used the average value of 10 times of measurement. A polarizing plate durability test can be performed in two types of forms which stuck only (1) a polarizing plate and (2) polarizing plate to glass via an adhesive, as follows. The measurement of only the polarizing plate of (1) combines so that the polarizing plate protective film of this invention may be sandwiched between two polarizers, and prepares two orthogonal and the same thing. The measurement in the form which affixed the polarizing plate of (2) to glass via an adhesive is two samples (about 5 cm x 5 cm) which affixed the polarizing plate on glass so that the polarizing plate protective film of this invention might be on a glass side. Manufacture. In a single-plate orthogonal transmittance measurement, the film side of this sample is set toward the light source and measured. Two samples are respectively measured and the average value is made into single plate orthogonal transmittance | permeability. In the Example of this invention, the test method of (2) was employ | adopted among the test methods of said (1) and (2).

As a preferable range of polarization performance, orthogonal transmittance CT is CT <= 2.0, and more preferable range is CT <= 1.3 (all units are%).

In the polarizing plate durability test, the change amount is preferably smaller. The change amount (%) of the orthogonal single-sheet transmittance | permeability at the time of letting it stand for 1000 hours at 70 degreeC and 80% of a relative humidity of the polarizing plate of this invention is 0.60% or less. It is preferable that it is 0.40% or less, and, as for the amount of change (%) of the orthogonal single-sheet transmittance | permeability when it is left to stand at 70 degreeC and 80% of relative humidity for 1000 hours, it is more preferable that it is 0.10% or less. Here, the change amount is a value obtained by subtracting the measured value before the test from the measured value after the test.

When the range of the change amount of the orthogonal transmittance is satisfied, stability during long time use or storage under high temperature, high humidity of a polarizing plate is preferable, and it is preferable.

<Functionalization of Polarizer>

The polarizing plate of the present invention is also preferable as a functionalized polarizing plate complexed with an optical film having an antireflection film, a brightness enhancement film for improving the visibility of a display, a functional layer such as a hard coat layer, a front scattering layer, an antiglare (antiglare) layer, and the like. Is used. The antireflection film for the functionalization, the brightness enhancement film, the other functional optical film, the hard coat layer, the front scattering layer, and the antiglare layer are described in Japanese Patent Application Laid-Open No. 2007-86748. The polarizing plate functionalized based on these base materials can be manufactured.

(Antireflection film)

The polarizing plate of the present invention can be used in combination with an antireflection film. As the antireflection film, both a film having a reflectance of about 1.5% which merely gives a low refractive index material such as a fluorine-based polymer or a film having a reflectance of 1% or less using multilayer interference of a thin film can be used. In this invention, the structure which laminated | stacked the low refractive index layer and the at least 1 layer (namely, the high refractive index layer, the medium refractive index layer) which has higher refractive index than the low refractive index layer on a transparent support body is used preferably. Moreover, the anti-reflective film of Nitto Kibo, vol. 38, No. 1, May, 2000, pages 26-28, Unexamined-Japanese-Patent No. 2002-301783, etc. can also be used preferably.

(Luminance improvement film)

The polarizing plate of this invention can be used in combination with a brightness improving film. The brightness enhancement film has a separation function of circularly polarized light or linearly polarized light, and is disposed between the polarizing plate and the backlight, and reflects one circularly polarized light or linearly polarized light to the backlight side or back scatters. Since the re-reflected light from the backlight portion is partially transmitted when the polarization state is changed and partially reenters the luminance enhancement film and the polarizing plate, the light utilization is improved by repeating this process, and the front luminance is about 1.4 times. Is improved. Anisotropic reflection system and anisotropic scattering system are known as a brightness improving film, and all can be combined with the polarizing plate in this invention.

(Other Functional Optical Films)

The polarizing plate of this invention is further combined with the functional optical film which formed the hard-coat layer, the front-scattering layer, the antiglare (anti-glare) layer, the gas barrier layer, the slip layer, the antistatic layer, the undercoat layer, the protective layer, etc. It is also preferable to use. Moreover, it is also preferable to use these functional layers together mutually in the same layer as the antireflection layer, optically anisotropic layer, etc. in the antireflection film mentioned above. These functional layers can be formed and used on either one or both surfaces of the polarizer side and the opposite surface (surface on the air side).

(Hard coat layer)

In order to provide mechanical strength, such as abrasion resistance, in the polarizing plate of this invention, combining a hard coat layer with the functional optical film formed in the surface of a transparent support body is performed preferably. When the hard coat layer is applied to the above-described antireflection film, it is particularly preferably formed between the transparent support and the high refractive index layer.

It is preferable that the above-mentioned hard-coat layer is formed by the crosslinking reaction of the curable compound by light and / or heat, or a polymerization reaction. As a curable functional group, a photopolymerizable functional group is preferable, or the organoalkoxysilyl compound is preferable for the organometallic compound containing a hydrolysable functional group. As a specific structural composition of a hard-coat layer, the thing of Unexamined-Japanese-Patent No. 2002-144913, 2000-9908, international publication 00/46617 pamphlet, etc. can be used preferably, for example.

It is preferable that the film thickness of a hard-coat layer is 0.2 micrometer-100 micrometers.

In the pencil hardness test according to JIS K 5400, the strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher. In the taper test according to JIS K 5400, the smaller the amount of abrasion of the test pieces before and after the test, the more preferable.

(Front scattering layer)

The front scattering layer is used to improve the viewing angle characteristics (color and luminance distribution) in the vertical and horizontal directions when the polarizing plate in the present invention is applied to the liquid crystal display device. In the present invention, the front scattering layer preferably has a binder dispersion of fine particles having different refractive indices. For example, Japanese Laid-Open Patent Publication No. 11-38208, which specifies the forward scattering coefficient, specifies the relative refractive index of the transparent resin and the fine particles. The structure of Unexamined-Japanese-Patent No. 2000-199809 made into the range, Unexamined-Japanese-Patent No. 2002-107512 which prescribed | regulated the haze value to 40% or more can be used. Moreover, in order to control the viewing angle characteristic of haze, it is also preferable to use the polarizing plate in this invention in combination with the "Lumisti" described in the technical report "optical functional film" pages 31-39 of Sumitomo Chemical Co., Ltd. It can be carried out.

(Antiglare Layer)

The antiglare (antiglare) layer is used to scatter the reflected light to prevent the reflected glare. The anti-glare function is obtained by forming irregularities on the outermost surface (display side) of the liquid crystal display device. The haze of the optical film having the anti-glare function is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.

As a method of forming irregularities on the surface of a film, for example, a method of forming irregularities on the surface of a film by adding fine particles (for example, JP-A 2000-271878, etc.), relatively large particles (particle size 0.05 to 2 micrometers) is added (0.1-50 mass%), and the method of forming a surface asperity film | membrane (for example, Unexamined-Japanese-Patent No. 2000-281410, 2000-95893, 2001-100004, 2001-281407) And the like, and a method of physically transferring an uneven shape to the surface of a film (for example, Japanese Patent Application Laid-Open No. 63-278839, Japanese Patent Laid-Open No. H11-183710, Japanese Patent Laid-Open No. 2000-A) as an embossing method. 275401 etc.) etc. can be used preferably.

[Liquid crystal display device]

The liquid crystal display device of this invention includes a liquid crystal cell and the polarizing plate of this invention arrange | positioned in at least one of this liquid crystal cell, and is arrange | positioned so that the optical film of this invention contained in the polarizing plate mentioned above may become outermost layer. .

(Composition of General Liquid Crystal Display)

The liquid crystal display device comprises a liquid crystal cell formed by supporting a liquid crystal between two electrode substrates, two polarizing plates disposed on both sides thereof, and a configuration in which at least one optical compensation film is disposed between the liquid crystal cell and the polarizing plate as necessary. Have

The liquid crystal layer of the liquid crystal cell is usually formed by encapsulating a liquid crystal in a space formed by placing a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive material. In the liquid crystal cell, a gas barrier layer, a hard coat layer, or an undercoat layer (undercoat layer) (used for bonding the transparent electrode layer) may be further formed. These layers are normally formed on a board | substrate. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

(Type of liquid crystal display device)

The film of this invention can be used for the liquid crystal cell of various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (Super Twisted Nematic), VA (Vertically Aligned), Various display modes have been proposed, such as Electrically Controlled Birefringence (ECB), and Hybrid Aligned Nematic (HAN). Moreover, the display mode which orientation-divided the said display mode is also proposed. The optical film of this invention is effective also in the liquid crystal display device of any display mode. Moreover, it is effective also in any liquid crystal display device of a transmissive type, a reflective type, and a transflective type.

Example

Hereinafter, the present invention will be described in detail based on examples. Materials, reagents, amounts of substances, proportions thereof, operations, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following examples and is not limited.

&Lt; Production of optical film &

(Comparative Example 1)

[Formula 7]

[In the general formula (1), (meth) acrylic resin having a lactone ring structure in which R ⁴⁰¹ is a hydrogen atom, R ⁴⁰² and R ⁴⁰³ are methyl groups (copolymerization monomer mass ratio = methyl methacrylate / 2- (hydroxymethyl) Methyl acrylate = 75/15, lactone cyclization rate about 100%, content rate of lactone ring structure 19.4%, mass average molecular weight 133000, melt flow rate 6.5 g / 10min (240 degreeC, 10 kgf), Tg 131 degreeC} 90 mass A mixture of 5 parts by mass of acrylonitrile-styrene (AS) resin (Toyo AS AS20, manufactured by Toyo Styrene); Tg 127 ° C.] was supplied to a twin screw extruder, and melt-extruded into a sheet at about 280 ° C. to obtain a (meth) acrylic resin sheet having a lactone ring structure having a thickness of 160 μm. The unstretched sheet was stretched 2.0 times in the conveyance direction (MD) and 2.0 times in the width direction (TD) orthogonal to it under a temperature condition of 160 ° C, and the optical film of Comparative Example 1 (thickness: 40 µm, in-plane) Phase difference (DELTA) nd: 1 nm, thickness direction phase difference Rth: 1 nm) was obtained.

(Examples 1 and 2)

Except having changed extending | stretching conditions in Table 1 in the comparative example 1, it carried out similarly to the comparative example 1, and manufactured the optical film.

(Comparative Example 2)

According to the synthesis method described in Unexamined-Japanese-Patent No. 2010-261025 [0171]-[0173], the pellet of the glutarimide containing polymer was obtained. Next, this pellet was melted similarly to the optical film of the comparative example 1, and the optical film of the comparative example 2 was manufactured.

(Examples 3 and 4)

An optical film was produced in the same manner as in Comparative Example 2 except that the draw ratio of the film of Comparative Example 2 was set forth in Table 1 below.

<Evaluation of the optical film>

The film thickness was measured about each manufactured optical film, and the following physical property measurement and evaluation were performed. The results are shown in Table 1 below.

(Moisture permeability)

After cutting the optical film sample of each Example and the comparative example by the circle | round | yen of diameter 70mm, the value after 24 hours passed at 40 degreeC and 90% of a relative humidity by the method of JISZ0208 was converted into the 40 micrometer film thickness. It was used as the moisture permeability.

Moreover, the water vapor transmission rate of the obtained optical film was made a, and the water vapor transmission rate of the optical film of the comparative example 1 mentioned above was B, and the value of a / B was computed. The value of this a / B is described in Table 1.

(Elastic modulus)

According to the following method, the elastic modulus of MD and TD direction was measured.

Sample 10 mm x 150 mm (TD x MD) was humidified for 25 hours at 60% relative humidity for 2 hours, using a universal tensile tester STM T50BP manufactured by Toyo Baldwin, at 60 ° C for 60% relative humidity. In the atmosphere, the stress at the elongation rate of 0.1% and 0.5% was measured by the stretching treatment in the MD direction at an initial sample length of 50 mm and 10% / min, and the film elastic modulus E '(MD) in the MD direction was obtained. .

Similarly, extending | stretching process was performed on the same conditions in the TD direction using 150 mm x 10 mm (TD x MD) of the sample, and the film elastic modulus E '(TD) of the TD direction was calculated | required.

<Production of Polarizing Plate>

1) saponification of the film

After immersing a commercially available cellulose triacetate film (Fujitak ZRD40, Fujifilm Co., Ltd.) for 2 minutes in 1.5 mol / L NaOH aqueous solution (saponification liquid) maintained at 55 degreeC, the film was washed with water, after that After immersing in a 25 mol of 0.05 mol / L sulfuric acid aqueous solution for 30 seconds, the water bath was further passed under 30 seconds of running water to make the film neutral. And water removal by the air knife was repeated 3 times, after removing water, it was made to dry for 15 second in the 70 degreeC dry zone, and the saponified film was produced.

2) manufacture of polarizer

According to Example 1 of Unexamined-Japanese-Patent No. 2001-141926, iodine was made to adsorb | suck to the stretched polyvinyl alcohol film, and the polarizer of 20 micrometers in thickness was manufactured.

3) bonding

After the corona treatment was performed to each optical film manufactured using the acrylic adhesive agent on the single side | surface of this polarizer, it bonded together. The said saponified commercially available cellulose triacetate film was affixed using the polyvinyl alcohol-type adhesive agent on the other side, and it dried at 70 degreeC for 10 minutes or more, and manufactured the polarizing plate. Here, the transmission axis of the polarizer and the transport direction of the film were arranged so as to be perpendicular to each other.

Using the polarizing plate manufactured as mentioned above, the liquid crystal display device was manufactured according to the following method, and the polarizing plate durability after time-lapse of high temperature, high humidity environment was evaluated. The results are shown in Table 1 below.

<Evaluation of the polarizing plate durability>

About the polarizing plates of each Example and comparative example manufactured above, the orthogonal transmittance CT of the polarizer in wavelength 410nm was measured using UV3100PC (made by Shimadzu Corporation), and the average value of 10 times of measurements was used.

The polarizer durability test was carried out as follows, in which the polarizer plate was attached to glass with an adhesive agent interposed therebetween. Two samples (about 5 cm * 5 cm) which affixed the polarizing plate on the glass with the cellulose triacetate film on the glass side were produced. In the single-plate orthogonal transmittance measurement, the film side of this sample is set to face a light source and measured. Two samples were respectively measured, and the average value was regarded as the orthogonal transmittance of the polarizing plate.

Then, orthogonal transmittance | permeability was measured by the same method with respect to 1000 hours after storing for 1000 hours in 70 degreeC and 80% of the relative humidity. The change in the orthogonal transmittance before and after the elapse of time is obtained, and the result is shown in the following Table 1 as the polarizer durability.

A: change in orthogonal transmittance is less than 0.1

B: change in orthogonal transmittance is 0.1 or more and less than 0.15

C: change in orthogonal transmittance is 0.15 or more

As is clear from the results shown in Table 1, the optical films of Examples 1 to 4, in which the moisture permeability is 90 g / m 2 / day or less, the elastic modulus change before and after stretching is 1.5 times or more, and the moisture permeability change is 0.9 times or less, all at high temperature and high humidity. Under the polarizing plate durability was excellent.

In contrast, the optical films of Comparative Examples 1 and 2, which have a moisture permeability of 90 g / m 2 / day or less and do not satisfy the condition that the change in elastic modulus before and after stretching is 1.5 times or more and the moisture permeability change is 0.9 times or less, are high temperature and high humidity. Under polarizing plate durability was inferior.

Claims (8)

As an optical film containing a thermoplastic resin,
The water vapor transmission rate of the said optical film is 90 g / m <2> / day or less, and by elongation, the elasticity modulus in either the conveyance direction or the width direction of the said optical film will be 1.5 times or more with respect to the elasticity modulus when it is not extended,
Also
The optical film whose water vapor transmission rate after extending | stretching becomes 0.9 times or less before extending | stretching.
(However, the moisture permeability is a value after the passage of 24 hours at 40 ° C. and a relative humidity of 90% by the method of JIS Z 0208.) The method of claim 1,
The optical film whose film thickness is 60 micrometers or less. The optical film which has a functional layer with a film thickness of 0.1-20 micrometers in the at least one surface of the optical film of Claim 1. The method of claim 3, wherein
The water vapor transmission rate (C) of the optical film in the case of laminating | stacking the said functional layer, and the water vapor transmission rate (D) of the optical film in the absence of lamination of the said functional layer become C / D <= 0.9. The method of claim 1,
The optical film in which the said thermoplastic resin contains acrylic resin which has a cyclic structure. By stretching the film containing a thermoplastic resin so that the elasticity modulus of either a conveyance direction or the width direction may become 1.5 times, and a water vapor transmission rate becomes 0.9 times or less, the optical film which manufactures the optical film whose water vapor transmission rate is 90 g / m <2> / day or less Manufacturing method. The polarizing plate containing at least 1 optical film as described in any one of Claims 1-5 as a protective film of a polarizer. With a liquid crystal cell,
It includes the polarizing plate of Claim 7 arrange | positioned in at least one of the said liquid crystal cell,
The liquid crystal display device arrange | positioned so that the said optical film may become outermost layer.

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