KR20090056904A - Method for producing optical film laminate, optical film laminate, polarizing plate, and liquid crystal display device - Google Patents

Abstract

A method for producing an optical film laminate, an optical film laminate, a polarizing plate, and a liquid crystal display device are provided to have high contrast ratio and small color shifting. A method for producing an optical film laminate comprises the steps of: laminating cyclic olefin resin and vinyl aromatic system resin through a coextrude method; obtaining a cyclic olefin base resin layer and the disk film in which the vinyl aromatic system resin layer is laminated; and extending the obtained film in the length direction.

Description

Manufacturing method of laminated optical film, laminated optical film, polarizing plate, and liquid crystal display device {METHOD FOR PRODUCING OPTICAL FILM LAMINATE, OPTICAL FILM LAMINATE, POLARIZING PLATE, AND LIQUID CRYSTAL DISPLAY DEVICE}

TECHNICAL FIELD The present invention relates to a laminated optical film that realizes excellent viewing angle characteristics in a liquid crystal display device, a manufacturing method thereof, and a polarizing plate and a liquid crystal display device using the film.

The retardation film is generally used for the purpose of compensating the viewing angle of a liquid crystal display device, and serves to prevent light leakage at an oblique viewing angle and to prevent a decrease in contrast ratio. A polycarbonate film, a polyester film, a cellulose acetate film, a cyclic olefin film, etc. are mentioned to the optical film used as a retardation film.

Among them, the cyclic olefin film is attracting attention as a material for various optical parts including retardation film because of its excellent transparency, heat resistance, dimensional stability, low photoelasticity and the like.

In recent years, in addition to the conventional TN mode, high viewing angle liquid crystal modes of VA mode and IPS mode have been put into practical use, and liquid crystal display devices (liquid crystal televisions) have become widespread also in television applications requiring high image quality. For example, as a retardation film for the liquid crystal display device of VA mode, the compensation system which combined A plate and C plate, and the compensation system which combined one or two sheets of biaxial films are known to be especially effective in improving a viewing angle. have.

However, even in these compensation methods, the viewing angle compensation is not applied to changes in color when the screen is viewed from the inclined direction (hereinafter referred to as color shift), for example, purple color is displayed in the black display state. Insufficient. In order to improve this, it is known that a retardation film having a property such as a retardation becomes smaller as the shorter wavelength in the visible light region becomes larger and the retardation becomes larger as the longer wavelength becomes longer. For example, Patent Literature 1 below proposes a method for realizing reverse wavelength dispersion by modification of a resin used in a retardation film. However, the modification of the resin has made it difficult to establish the resin production conditions, and the strength, transparency, stability, and the like of the film are impaired.

As a method other than the modification of the resin, a layer of a specific phase difference may be laminated and controlled so that the total phase difference is reverse wavelength dispersion. For example, Patent Document 2 below proposes a method of realizing reverse wavelength dispersion by laminating a phase difference layer containing a polymerizable liquid crystal and a resin film. However, the retardation layer by a polymerizable liquid crystal has high manufacturing difficulty, for example, it is necessary to control a layer having a thickness of about several micrometers by several percent thickness variation. In the lamination method, a predetermined phase difference value and reverse wavelength dispersion are obtained when observed from the front direction, but when viewed from an inclined direction, the predetermined phase difference is not obtained due to the influence of the optical axis shift, and thus the tilted direction is obtained. There is a problem in that viewing angle compensation cannot be performed.

As another method for laminating the retardation layer, Patent Literature 3 below proposes film forming by the coextrusion method and retardation film production. However, there is a problem in that adhesion between the layers is poor and it is necessary to sandwich the adhesive layer between the layers, which complicates the layer structure and the manufacturing apparatus. As described above, a method for increasing the contrast ratio from the oblique direction and lowering the color shift has not been sufficiently established, and improvement has been required. In addition, in addition to the excellent viewing angle characteristics described above, in the liquid crystal display devices for portable devices such as mobile phones, portable game machines and the like, there is also a demand for durability to withstand long-term use in harsh environments.

[Patent Document 1] Japanese Patent Laid-Open No. 2006-225626

[Patent Document 2] Japanese Patent Application Laid-Open No. 2006-268033

[Patent Document 3] Japanese Unexamined Patent Publication No. 2004-133313

In the liquid crystal display device, the contrast ratio when the screen is viewed from the inclined direction is high, the amount of color shift when the screen is viewed from the inclined direction is small, and uniform screen display is enabled, and the durability is excellent. Another object of the present invention is to provide a laminated optical film having a low amount of external light shining, a method of manufacturing the same, a polarizing plate and a liquid crystal display device using the same.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in view of the above-mentioned situation, this inventor can implement | achieve the predetermined | prescribed phase difference and the reverse wavelength dispersion property which were seen in the inclination direction which became a problem in patent document 2, and the problem in patent document 3 It was discovered that the adhesion of each layer of the laminated film can be secured, and the present invention was completed.

The manufacturing method of the laminated optical film of this invention,

Cyclic olefin resin and vinyl aromatic resin are laminated | stacked into a film by the coextrusion method, and a cyclic olefin resin layer (henceforth (A) layer) and a vinyl aromatic resin layer (henceforth (B) layer) are formed. The process of obtaining this laminated disk film,

It has a process of uniaxially stretching the obtained raw film to a straight direction with respect to a film longitudinal direction,

It is characterized by obtaining a laminated optical film that satisfies all the properties represented by the following formulas i to iii.

[Equation i]

R450≤R550≤R650

[Equation ii]

1.0≤R650 / R550≤1.2

[Equation iii]

70 nm≤R550≤150 nm

[In formulas i to iii, R450, R550, and R650 represent in-plane retardation of the laminated optical film at wavelengths of 450 nm, 550 nm, and 650 nm in order.]

In the manufacturing method of the laminated optical film of this invention, it is preferable that cyclic olefin resin contains the copolymer which has a structural unit represented by following formula (1), and a structural unit represented by following formula (2).

[In formula 1, m is an integer of 1 or more, p is an integer of 0 or more, X is independently a group represented by the formula -CH = CH- or a group represented by the formula -CH ₂ CH _2- ,

R ¹ to R ⁴ each independently represent the ones represented by the following (a) to (e), or represent (f) or (g),

(a) a hydrogen atom,

(b) a halogen atom,

(c) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, including a linking group comprising an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom,

(d) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms,

(e) polar groups,

(f) R ¹ and R ² , or R ³ and R ⁴ represent an alkylidene group formed by bonding to each other, R ¹ to R ^{4 which} is not involved in the bond are independently selected from (a) to (e) Indicates that

(g) R ¹ and R ² , R ³ and R ⁴ , or R ² and R ³ represent an aromatic or non-aromatic monocyclic or polycyclic hydrocarbon ring or heterocyclic ring formed by bonding with each other, and are not involved in the bond. R ¹ to R ⁴ are independently selected from each other (a) to (e).

In Formula 2, Y is a group represented by the formula -CH = CH- or a group represented by the formula -CH ₂ CH _2- ,

R ⁵ to R ⁸ each independently represent the ones represented by the following (a) to (e), or represent (f) or (g),

(a) a hydrogen atom,

(b) a halogen atom,

(c) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, including a linking group comprising an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom,

(d) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms,

(e) polar groups,

(f) R ⁵ and R ⁶ , or R ⁷ and R ⁸ represent an alkylidene group formed by bonding to each other, and R ⁵ to R ^{8 which} are not involved in the bond are independently selected from (a) to (e) To become,

(g) R ⁵ and R ⁶ , R ⁷ and R ⁸ , or R ⁶ and R ⁷ represent an aromatic ring or a non-aromatic monocyclic or polycyclic hydrocarbon ring or heterocyclic ring formed by bonding with each other and are not involved in the above bond; R ⁵ to R ⁸ are independently selected from each other selected from the above (a) to (e)]

In the manufacturing method of the laminated optical film of this invention, it is preferable that vinyl aromatic resin is a styrene- (meth) acrylic acid copolymer, and also it is preferable that vinyl aromatic resin is a styrene-maleic anhydride copolymer.

In the manufacturing method of the laminated optical film of this invention, it is preferable that the cyclic olefin resin layer and the vinyl aromatic resin layer directly contact.

In the manufacturing method of the laminated optical film of this invention, it is preferable that cyclic olefin resin and vinyl aromatic resin have a relationship which satisfy | fills following formula (iv).

[Equation iv]

TgA (° C) -TgB (° C) | ≤20 (° C)

[In formula, TgA represents the glass transition temperature of cyclic olefin resin, TgB represents the glass transition temperature of vinyl aromatic resin.]

In the manufacturing method of the laminated optical film of this invention, it is preferable that both the glass transition temperature (TgA) of cyclic olefin resin and the glass transition temperature (TgB) of vinyl aromatic resin are 110 degreeC or more.

The laminated optical film of the present invention is characterized in that the cyclic olefin resin layer and the vinyl aromatic resin layer are in direct contact with each other and laminated, and satisfy all the characteristics of the following formulas (i) to (iii).

Equation i

R450≤R550≤R650

<Equation ii>

1.0≤R650 / R550≤1.2

<Equation iii>

70 nm≤R550≤150 nm

[In formulas i to iii, R450, R550, and R650 represent in-plane retardation of the laminated optical film at wavelengths of 450 nm, 550 nm, and 650 nm in order.]

It is preferable that the optical film of this invention satisfy | fills following formula (v) further.

[Equation v]

1.0≤NZ≤3.0

[Wherein, NZ is a coefficient expressed by NZ = (nx−nz) / (nx−ny) and a value at a wavelength of 550 nm, where nx is the maximum refractive index in the laminated optical film plane, ny represents the refractive index of the direction orthogonal to nx in a laminated optical film plane, nz represents the refractive index of the laminated optical film thickness direction orthogonal to nx and ny, provided that the average refractive index of a laminated optical film is N _ave , N _ave = (nx + ny + nz) / 3, N _ave is a weighted average of the average refractive indices of each of the cyclic olefin resin layer and the vinyl aromatic resin layer in the thickness ratio of the laminated optical film]

In the laminated optical film of this invention, it is preferable that both the glass transition temperature of cyclic olefin resin and the glass transition temperature of vinyl aromatic resin are 110 degreeC or more.

The laminated optical film of this invention is obtained by the manufacturing method of the laminated optical film of said this invention, It is characterized by the above-mentioned.

The polarizing plate of the present invention is characterized in that the laminated optical film of the present invention is laminated on at least one surface of the polarizer via an adhesive or an adhesive. It is preferable that such a polarizing plate of the present invention further has at least one layer selected from an antireflection layer and an antiglare layer.

The liquid crystal display device of the present invention has any one of the polarizing plates of the present invention.

By the laminated optical film of this invention, in a liquid crystal display device, the contrast ratio at the time of viewing a screen from the inclination direction is high, and the amount of color shift at the time of viewing the screen from the inclination direction is small, and liquid crystal which enables uniform screen display is possible. A display device is obtained.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely.

[Method for Manufacturing Laminated Optical Film]

The manufacturing method of the laminated optical film of this invention,

A step of laminating a cyclic olefin resin and a vinyl aromatic resin by coextrusion to obtain a raw film in which the cyclic olefin resin layer and the vinyl aromatic resin layer are laminated;

It has a process of uniaxially stretching the obtained raw film to a straight direction with respect to a film longitudinal direction.

Cyclic olefin resin

The cyclic olefin resin used in the present invention is not particularly limited, and a ring-opening (co) polymer of a cyclic olefin monomer having a norbornene skeleton, a hydrogenated product of a ring-opening (co) polymer, an addition (co) polymer, or Copolymers of cyclic olefin monomers and other copolymerizable monomers, hydrogenated products thereof, and the like. Preferably, the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) ) Is a copolymer. It may also optionally include other structural units.

The copolymer is also referred to as at least one monomer represented by the following formula (3) (hereinafter also referred to as "monomer (1)") and at least one monomer represented by the following formula (4) (hereinafter referred to as "monomer (2)"). ) Is obtained by ring-opening copolymerization.

(Definition of m, p, R ¹ , R ² , R ³ and R ^{4 in} the formula (3) is the same as the definition of the formula (1).)

(The definition of R <^5> , R <^6> , R <^7> and R <^8> is the same as the definition of Formula (2) in Formula (4).

In Formulas 1 to 4, R ¹ to R ⁸ may be selected from a hydrogen atom; Halogen atom; A substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; Or a polar group. The said atom and group are demonstrated below.

As a halogen atom, a fluorine atom, a chlorine atom, and a bromine atom are mentioned.

As a hydrocarbon group of 1-30 carbon atoms, For example, Alkyl groups, such as a methyl group, an ethyl group, and a propyl group; Cycloalkyl groups such as cyclopentyl group and cyclohexyl group; Alkenyl groups, such as a vinyl group, an allyl group, and a propenyl group, etc. are mentioned.

In addition, the substituted or unsubstituted hydrocarbon group may be directly bonded to the ring structure, or may be bonded through a linkage. Examples of the linking group include a divalent hydrocarbon group having 1 to 10 carbon atoms (for example, an alkylene group represented by-(CH ₂ ) m-(wherein m is an integer of 1 to 10)); Linking groups containing oxygen, nitrogen, sulfur or silicon (e.g. carbonyl group (-CO-), oxycarbonyl group (-0 (CO)-), sulfone group (-SO _2- ), ether bond (-O-) , Thioether bond (-S-), imino group (-NH-), amide bond (-NHCO-, -CONH-), siloxane bond (-OSi (R ₂ )-(where R is methyl, ethyl, etc.) Alkyl group)) and the like, and may be a linking group containing a plurality of these groups.

Examples of the polar group include a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group, an aryloxycarbonyl group, a cyano group, an amide group, an imide ring-containing group, a triorganosiloxy group, a triorganosilyl group, an amino group, and the like. An acyl group, an alkoxy silyl group, a sulfonyl containing group, a carboxyl group, etc. are mentioned. More specifically, as said alkoxy group, a methoxy group, an ethoxy group, etc. are mentioned, for example; As an alkoxycarbonyl group, a methoxycarbonyl group, an ethoxycarbonyl group, etc. are mentioned, for example; Examples of the aryloxycarbonyl group include phenoxycarbonyl group, naphthyloxycarbonyl group, fluorenyloxycarbonyl group, biphenylyloxycarbonyl group, and the like; Examples of the triorganosiloxy group include trimethylsiloxy group, triethylsiloxy group, and the like; Examples of the triorganosilyl group include trimethylsilyl group and triethylsilyl group; Primary amino group is mentioned as an amino group, For example, a trimethoxy silyl group, a triethoxy silyl group, etc. are mentioned as an alkoxy silyl group.

As a more specific example of cyclic olefin resin in this invention, the copolymer shown to following <1>-<3> is mentioned. Among these, the copolymer shown in <3> is especially preferable at the point which has the outstanding thermal stability and is excellent in the optical characteristic.

<1> Ring-opening copolymer of monomer (1) and monomer (2).

<2> Ring-opening copolymer of monomer (1), monomer (2), and another copolymerizable monomer.

<3> Hydrogenated substance of the ring-opening copolymer of <1> and <2>.

Monomer (1)

The structural unit (1) is usually derived from monomer (1). Although the specific example of monomer (1) is given to the following, this invention is not limited to these specific examples. In addition, the monomer (1) can also be used in combination of 2 or more type.

Tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

^Pentacyclo [6.5.1.1 ^{3,6 2,7} .0 ^9,13 ] -4- ^pentadecene ,

Pentacyclo [7.4.0.1 ^2,5 .1 ^9,12 .0 ^8,13 ] -3- ^pentadecene ,

Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,

8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-phenoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-phenoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

Pentacyclo [8.4.0.1 ^2,5 .1 ^9,12 .0 ^8,13 ] -3-hexadecene,

Heptacyclo [8.7.0.1 ^3,6 .1 ^10,17 .1 ^12,15 .0 ^2,7 .0 ^11,16 ] -4-eicosene,

Heptacyclo [8.8.0.1 ^4,7 .1 ^11,18 .1 ^13,16 .0 ^3,8 .0 ^12,17 ] -5- ^heneicosene ,

8-ethylidenetetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-phenyl-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3- dodecene,

8-methyl-8-phenyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-fluorotetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-fluoromethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-difluoromethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-pentafluoroethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8-difluorotetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,9-difluorotetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,9-difluoro-8-heptafluoro iso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene

Etc. can be mentioned.

Among them, it is preferable to use the monomer (1) having one or more polar groups in the molecule. That is, in Formula 3, R ¹ and R ³ are a hydrogen atom or a hydrocarbon group of 1 to 10 carbon atoms, R ² and R ⁴ is a hydrogen atom or a monovalent organic group, at least one of R ² and R ⁴ Polar groups other than this hydrogen atom and a hydrocarbon group are preferable in order to improve adhesiveness and adhesiveness with other raw materials.

Although content of the polar group in a copolymer is determined by a desired function etc., it does not specifically limit, In order to improve adhesiveness and adhesiveness with another raw material, the structural unit (1) which has a polar group in all the structural units (1) is normally 50 mol% or more, Preferably it is 70 mol% or more, More preferably, it is contained 80 mol% or more. The entire structural unit (1) may have a polar group. By presence of a polar group, adhesiveness with the vinyl aromatic resin layer in a coextrusion film forming can be improved.

Moreover, the monomer (1) whose one or more of R <^2> and R <^4> is a polar group represented by following formula (5) is preferable at the point which is easy to control the glass transition temperature and water absorption of the copolymer obtained. As a monovalent organic group represented by R <^9> in General formula (5), For example, Alkyl groups, such as a methyl group, an ethyl group, and a propyl group; Aryl groups, such as a phenyl group, a naphthyl group, anthracenyl group, and a biphenylyl group; In addition, monovalent groups which have aromatic rings, such as fluorenes, such as diphenyl sulfone and tetrahydrofluorene, and heterocycles, such as a furan ring and an imide ring, etc. are mentioned.

-(CH ₂ ) _n COOR ⁹

[Where n is usually an integer of 0 to 5, preferably an integer of 0 to 2, more preferably 0, and R ⁹ is a monovalent organic group]

In addition, in the general formula (5), n is an integer of 0 to 5 as described above, and the smaller the value of n, the higher the glass transition temperature of the obtained copolymer is preferable, and especially monomer (1) in which n is 0 is And the synthesis thereof is preferable.

In addition, in said Formula (3), it is preferable that an alkyl group couple | bonds with the carbon atom which the polar group represented by Formula (5) couple | bonded further in order to balance the heat resistance and water absorption of the copolymer obtained. It is preferable that carbon number of the said alkyl group is 1-5, More preferably, it is 1-2, Especially preferably, it is 1.

Moreover, the monomer (1) in which m is 1 and p is 0 in general formula (3) is preferable at the point from which the copolymer with high glass transition temperature is obtained.

For example, among specific examples of the monomer (1), for example, in particular 8-methyl-8-methoxy-carbonyl tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3-dodecene is, the resultant copolymer It is preferable because it can raise the glass transition temperature and hardly receive adverse effects such as deformation due to absorption, and can maintain absorbency to the extent that adhesion and adhesion with other materials are good.

Monomer (2)

Structural unit (2) is derived from monomer (2). Although the specific example of monomer (2) is given to the following, this invention is not limited to these specific examples. In addition, the monomer (2) can also be used in combination of 2 or more type.

Bicyclo [2.2.1] hept-2-ene (norbornene),

5-methylbicyclo [2.2.1] hept-2-ene,

5-ethylbicyclo [2.2.1] hept-2-ene,

5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,

5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,

5-phenoxycarbonylbicyclo [2.2.1] hept-2-ene,

5-methyl-5-phenoxycarbonylbicyclo [2.2.1] hept-2-ene,

5-cyanobicyclo [2.2.1] hept-2-ene,

5-ethylidenebicyclo [2.2.1] hept-2-ene,

5-phenylbicyclo [2.2.1] hept-2-ene,

5- (2-naphthyl) bicyclo [2.2.1] hept-2-ene (both types of α and β are possible),

5-fluorobicyclo [2.2.1] hept-2-ene,

5-fluoromethylbicyclo [2.2.1] hept-2-ene,

5-trifluoromethylbicyclo [2.2.1] hept-2-ene,

5-pentafluoroethylbicyclo [2.2.1] hept-2-ene,

5,5-difluorobicyclo [2.2.1] hept-2-ene,

5,6-difluorobicyclo [2.2.1] hept-2-ene,

5,5-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5-methyl-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,

5,5,6-trifluorobicyclo [2.2.1] hept-2-ene,

5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,5,6,6-tetrafluorobicyclo [2.2.1] hept-2-ene,

5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,

5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,6-difluoro-5-heptafluoro-iso-propyl-6-trifluoromethylbicyclo [2.2.1] hept-2-ene,

5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene,

5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.1] hept-2-ene,

5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-ene,

5- (4-phenylphenyl) bicyclo [2.2.1] hept-2-ene,

4- (bicyclo [2.2.1] hept-5-en-2-yl) phenylsulfonylbenzene,

Tricyclo [5.2.1.0 ^2,6 ] -8-decene,

Tricyclo [4.3.0.1 ^2,5 ] deck-3,7-diene (dicyclopentadiene)

Etc. can be mentioned.

Among them, monomers (2) in which all of R ⁵ to R ^{8 in the general} formula (4) are hydrogen atoms or one of them is a hydrocarbon group having 1 to 30 carbon atoms and the other is a hydrogen atom improve the toughness of the resulting optical film. The effect is preferable, and especially the monomer in which all of R <^5> -R <^8> is a hydrogen atom or all one is a methyl group, an ethyl group, or a phenyl group, and all others are hydrogen atoms are also preferable from a heat resistant viewpoint. Bicyclo [2.2.1] hept-2-ene (norbornene), 5-phenylbicyclo [2.2.1] hept-2-ene, tricyclo [4.3.0.1 ^2,5 ] deck-3, 7-diene (dicyclopentadiene) is preferable at the point which the synthesis | combination is easy, the point which can improve the toughness of resin, adjustment of glass transition temperature, and favorable coextrusion moldability.

In the present invention, the ratio of monomer (1) to monomer (2) is usually used as a weight ratio of monomer (1): monomer (2) = 95: 5 to 5:95, preferably 95: 5 to 60:40. More preferably 95: 5 to 70:30, still more preferably 95: 5 to 75:25. If the ratio of the monomer (1) is larger than the above range, the effect of improving the toughness may not be expected. On the contrary, if the ratio of the monomer (1) is smaller than the above range, the glass transition temperature is lowered, causing problems in heat resistance. have.

Moreover, in order to improve adhesiveness and adhesiveness with another raw material, the structural unit which has a polar group in the whole quantity of the structural unit (1) and the structural unit (2) is 50-95 mol% normally, Preferably it is 70-95 mol%, Furthermore, Preferably 80-95 mol% or more is included. By presence of a polar group, adhesiveness with the vinyl aromatic resin layer in a coextrusion film forming can be improved.

<Other Copolymerizable Monomers>

As another copolymerizable monomer which can be copolymerized with the monomer (1) and the monomer (2), for example, cyclobutene, cyclopentene, cycloheptene, cyclooctene, tricyclo [5.2.1.0 ^2,6 ] -3-decene and the like And cycloolefins. As carbon atom number of a cycloolefin, 4-20 are preferable, More preferably, it is 5-12. These copolymerizable monomers are useful for the modification of resin, such as retardation expression improvement, Tg adjustment, and moldability improvement.

In addition, the monomer (1) and the monomer ( 2) may be polymerized. And the copolymer obtained in this case is useful as a raw material of resin with high impact resistance.

The use ratio of the monomer (1) and the monomer (2) and the copolymerizable cyclic monomer or the unsaturated double bond-containing compound is [monomer (1) + monomer (2)]: [copolymerizable cyclic monomer or unsaturated double bond-containing compound] It is preferable that it is 100: 0-50: 50 by weight ratio, More preferably, it is 100: 0-60: 40, More preferably, it is 100: 0-70: 30.

<Opening polymerization catalyst>

The ring-opening polymerization reaction of the specific monomer is carried out in the presence of a metathesis catalyst. This metathesis catalyst comprises at least one metal compound selected from tungsten compounds, molybdenum compounds and rhenium compounds (hereinafter referred to as "(a) component"), group 1 elements of the periodic table (for example, Li, Na, K, etc.), Group 2 elements (eg Mg, Ca, etc.), Group 12 elements (eg Zn, Cd, Hg, etc.), Group 13 elements (eg B, Al, etc.), Group 4 elements (eg For example, Ti, Zr, etc.) or a compound of group 14 element (for example, Si, Sn, Pb, etc.), at least one compound selected from one or more of the above element-carbon bond or the element-hydrogen bond (Hereinafter, referred to as "(b) component"), an additive (hereinafter referred to as "(c) component") may be contained in order to enhance the catalytic activity.

Wherein (a) Specific examples of the preferred metal compounds constituting the component, WCl _6, MoCl _5, there may be mentioned metal compounds described in Japanese Unexamined Patent Publication (Kokai) No. 1-240517 Publication, such as ReOCl _3.

Specific examples of the compound constituting the component (b) include nC ₄ H ₉ Li, (C ₂ H ₅ ) ₃ Al, (C ₂ H ₅ ) ₂ AlCl, (C ₂ H ₅ ) _1.5 AlCl _1.5 , (C ₂ H ₅₎ AlCl _2, there may be mentioned compounds described in Japanese Unexamined Patent Publication (Kokai) No. 1-240517 Publication, such as methyl aluminoxane, LiH.

As the component (c), alcohols, aldehydes, ketones, amines and the like can be preferably used, but other compounds described in JP-A-240517 can be used.

As a metathesis catalyst other than the components (a), (b) and (c), a ruthenium compound known as a Grubbs catalyst may also be used.

<Hydrogenated>

The hydrogenation rate in the hydrogenated (co) polymer shown in the above <3> is usually 50% or more, preferably 70% or more, more preferably 90% or more, still more preferably 97% or more, particularly preferably 99% or more.

It is preferable that cyclic olefin resin used for this invention is _0.2-5.0 dl / g in intrinsic viscosity ((eta) h) measured in 30 _degreeC chloroform.

The average molecular weight of the cyclic olefin resin is preferably in the range of 8,000 to 100,000 and the weight average molecular weight (Mw) in the range of 20,000 to 300,000 in the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC). Do.

In addition, the glass transition temperature (TgA) of the cyclic olefin resin is preferably 100 to 250 ° C, more preferably 110 to 180 ° C, still more preferably 120 to 170 in order to ensure thermal stability and coextrusion moldability. ℃. In addition, the cyclic olefin resin film used by this invention may be formed from the resin composition containing the cyclic olefin resin as mentioned above. In addition to the cyclic olefin resin, the resin composition includes an antioxidant, a heat stabilizer, a light stabilizer, a phase difference regulator, an ultraviolet absorber, an antistatic agent, a dispersant, a processability improving agent, a chlorine trapping agent, a flame retardant, a crystallization nucleating agent, an antiblocking agent, and an antifogging agent as necessary. Known additives such as mold release agents, pigments, organic or inorganic fillers, neutralizing agents, lubricants, disintegrating agents, metal deactivators, antifouling agents, antibacterial agents or other resins, thermoplastic elastomers, etc., within the scope of not impairing the effect of the invention. can do.

vinyl Aromatic  Suzy

The vinyl aromatic resin used in the present invention preferably has a structural unit (6) represented by the following formula (6).

In formula (6), R ¹⁰ represents a hydrogen atom or a methyl group, and R ¹¹ to R ¹³ each independently represent a hydrogen atom; Halogen atom; A substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; Or polar group]

Specific examples of the monomer for inducing structural unit (6) include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, p-trifluoromethylstyrene, p-methoxystyrene, p-hydroxystyrene, p-chlorostyrene, p-nitrostyrene, p-aminostyrene, p-carboxystyrene, p-phenylstyrene, p-tert-butoxystyrene, 2,4,6-trimethylstyrene, etc. are mentioned. These monomers may be used alone or in combination of two or more. Among these monomers, styrene, α-methylstyrene, and p-hydroxystyrene are preferably used alone or in combination.

In addition, the vinyl aromatic resin preferably has a structural unit (7) represented by the following formula (7) and / or a structural unit (8) represented by the following formula (8).

In formula (7), X is an oxygen atom or a nitrogen atom which has a substituent, In formula (8), R <^15> is a hydrogen atom or a C1-C30 hydrocarbon group, As a C1-C30 hydrocarbon group, a For example, alkyl groups, such as a methyl group, an ethyl group, and a propyl group; Cycloalkyl groups such as cyclopentyl group and cyclohexyl group; Alkenyl groups, such as a vinyl group, an allyl group, and a propenyl group, etc. are mentioned, R <^14> represents a hydrogen atom or a methyl group.]

The vinyl aromatic resin may be a structure including both the structural unit (7) and the structural unit (8), or may be a structure including only one of the structural unit (7) and the structural unit (8). The acid anhydride structure or imide structure of the structural unit (7) may be hydrolyzed to form a dicarboxylic acid structure or an amic acid structure.

Specific examples of the monomer for inducing the structural unit (7) include N-substituted maleimides such as maleic anhydride, maleimide and N-phenylmaleimide, maleic acid and derivatives thereof, fumaric acid and derivatives thereof, and the like. These monomers may be used alone or in combination of two or more. Of these monomers, maleic anhydride and N-phenylmaleimide are preferably used in terms of heat resistance and adhesiveness with the cyclic olefin resin layer.

As a specific example of the monomer which guide | induces a structural unit (8), (meth) acrylic-acid alkylesters, such as (meth) acrylic acid and (meth) acrylic acid, (meth) acrylic acid amide, etc. are mentioned. These monomers may be used alone or in combination of two or more. Among these monomers, (meth) acrylic acid and methyl (meth) acrylate are preferably used in view of heat resistance and adhesiveness with a cyclic olefin resin layer.

In the present invention, the use ratio of the structural unit (6) and the structural unit (7) and / or the structural unit (8) in the vinyl aromatic resin is usually in the weight ratio of the structural unit (6): [structural unit (7) + Structural unit (8)] = 100: 0 to 50:50, preferably 98: 2 to 60:40, more preferably 95: 5 to 70:30. By the use ratio being in the said range, adjustment of glass transition temperature, adjustment of phase difference expression property, ensuring coextrusion moldability, and ensuring adhesiveness with a cyclic olefin resin layer are attained.

In addition to the structural unit (7) and the structural unit (8), other monomers such as ethylene, propylene, butene, butadiene, isoprene, (meth) acrylonitrile, α-chloroacrylonitrile, vinyl acetate, vinyl chloride and the like as necessary It may also be included as a copolymerization component.

As for the vinyl aromatic resin used for this invention, it is preferable that the logarithmic viscosity ((eta)) measured in 30 degreeC chlorobenzene solution (concentration 0.5 g / dL) is 0.1-3.0 dL / g. In addition, the weight average molecular weight Mw of polystyrene conversion measured by gel permeation chromatography (GPC) is usually 30,000 to 1,000,000, preferably 40,000 to 800,000, and more preferably 50,000 to 500,000. When molecular weight is too small, the strength of molded articles, such as a film obtained, may fall. When molecular weight is too big, solution viscosity may become high too much and productivity and workability of the resin composition used for this invention may deteriorate.

Moreover, the molecular weight distribution (Mw / Mn) of vinyl aromatic resin is 1.0-10 normally, Preferably it is 1.2-5.0, More preferably, it is 1.2-4.0.

It is preferable to manufacture the vinyl aromatic resin used for this invention by the method of polymerizing-reacting the said monomer which guides structural units (6), (7), (8) in presence of a suitable polymerization initiator. As a polymerization initiator, it is preferable to use a radical polymerization initiator, an anion polymerization catalyst, a coordination polymerization catalyst, a cationic polymerization catalyst, etc., and it is especially preferable to use a radical polymerization initiator.

As a radical initiator used for a polymerization reaction, the well-known organic peroxide which generate | occur | produces a free radical, or an azobis type radical polymerization initiator can be used. Moreover, since the linearity of the styrenic copolymer obtained may fall, the polyfunctional initiator or the initiator which is easy to cause a hydrogen release reaction is not preferable.

Examples of the organic peroxide include diacetyl peroxide, dibenzoyl peroxide, diisobutyroyl peroxide, di (2,4-dichlorobenzoyl) peroxide, di (3,5,5-trimethylhexanoyl) peroxide and diocta Diacyl peroxides such as noyl peroxide, dilauroyl peroxide, distearoyl peroxide, and bis {4- (m-toluyl) benzoyl} peroxide;

Ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide and acetylacetone peroxide;

Hydrogen peroxide, t-butylhydroperoxide, α-cumene hydroperoxide, p-mentane hydroperoxide, diisopropylbenzenehydroperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, t-hexylhydro Hydroperoxides such as loperoxide;

Di-t-butylperoxide, dicumylperoxide, dilaurylperoxide, α, α'-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-bis (t-butyl Dialkyl peroxides such as peroxy) hexane, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexine-3;

t-butylperoxy acetate, t-butylperoxy pivalate, t-hexyl peroxy pivalate, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, 2,5-dimethyl-2 , 5-bis (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy 2-ethylhexanoate, t-hexylperoxy 2-ethylhexanoate, t-butylperoxy 2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxymaleate, t-butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5 -Dimethyl-2,5-bis (m-toluoylperoxy) hexane, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxy neodecanoate, 1,1,3, 3-tetramethylbutylperoxy neodecanoate, 1-cyclohexyl-1-methylethylperoxy neodecanoate, t-hexylperoxy neodecanoate, t-butylperoxy neodecanoate, t- Butyl peroxy benzoate, t-hexyl peroxy benzo Citrate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxy m-toluoylbenzoate, 3,3 ', 4, Peroxy esters such as 4'-tetra (t-butylperoxycarbonyl) benzophenone;

1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) 3 , 3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 2,2-bis (t-butylper Peroxy ketals such as oxy) butane, n-butyl 4,4-bis (t-butylperoxy) pivalate and 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane;

t-hexyl peroxy isopropyl monocarbonate, t-butyl peroxy isopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-butyl peroxy allyl monocarbonate, etc. Peroxy monocarbonates;

Di-sec-butylperoxydicarbonate, di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2 -Ethoxyethylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-2-methoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydica Peroxydicarbonates such as carbonate;

Although t-butyl trimethylsilyl peroxide etc. are mentioned, The organic peroxide used for this invention is not limited to these exemplary compounds.

Examples of azobis radical polymerization initiators include azobisisobutyronitrile, azobisisovaleronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2'- Azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2- (carbox Barmoyl azo) isobutyronitrile, 2,2'-azobis [2-methyl-N- {1,1-bis (hydroxymethyl) -2-hydroxyethyl} propionamide], 2,2'- Azobis [2-methyl-N- {2- (1-hydroxybutyl)} propionamide], 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], 2,2'-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azo Bis (N-cyclohexyl-2-methylpropionamide), 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'- Azobis [2- (2-imidazolin-2-yl) Ropan] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 2,2'-azobis [2- (3,4, 5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- {1- (2-hydroxyethyl) -2-imidazolin-2-yl} Propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2 , 2'-azobis [N- (2-carboxyethyl) -2-methyl-propionamidine], 2,2'-azobis (2-methylpropionamidoxime), dimethyl 2,2'-azobisbutyrate And 4,4'-azobis (4-cyanopentanoic acid, 2,2'-azobis (2,4,4-trimethylpentane) and the like, but the azobis-based radical polymerization initiator used in the present invention It is not limited to these exemplary compounds.

The usage-amount of these radical initiators is 0.01-5 mol% normally, Preferably it is 0.03-3 mol%, More preferably, it is 0.05-2 mol% in 100 mol% of monomer whole quantity which induces a vinyl aromatic resin.

In addition, a catalyst may be used for the polymerization reaction of the monomer which induces the vinyl aromatic resin. This catalyst is not specifically limited, For example, a well-known anionic polymerization catalyst, a coordination polymerization catalyst, a cationic polymerization catalyst, etc. are mentioned.

The polymerization reaction of the monomers for inducing the vinyl aromatic resin may be carried out in the presence of the polymerization initiator or catalyst, such as a bulk polymerization method, a solution polymerization method, a precipitation polymerization method, an emulsion polymerization method, a suspension polymerization method or a bulk-suspension polymerization method. It is performed by copolymerizing by a conventionally well-known method.

The solvent used for the solution polymerization is not particularly limited as long as it dissolves the monomers and polymers. Examples thereof include hydrocarbon solvents such as cyclohexane, aromatic hydrocarbon solvents such as toluene, and ketone solvents such as methyl ethyl ketone. Do. It is preferable that the usage-amount of a solvent is the quantity of 0 to 3 times (weight ratio) with respect to the said monomer whole quantity.

The polymerization reaction time is usually 1 to 30 hours, preferably 3 to 20 hours, and the polymerization reaction temperature is not particularly limited because it depends on the type of radical initiator to be used, but is usually 40 to 180 ° C, preferably 50-120 degreeC.

Glass transition temperature (TgB) of vinyl aromatic resin is 110-200 degreeC, More preferably, it is 120-170 degreeC, in order to ensure thermal stability and coextrusion moldability. The vinyl aromatic resin film used by this invention may be formed from the resin composition containing vinyl aromatic resin as mentioned above. In the resin composition, in addition to the vinyl aromatic resin, an antioxidant, a heat stabilizer, an optical stabilizer, a phase difference regulator, an ultraviolet absorber, an antistatic agent, a dispersant, a processability improvement agent, a chlorine trapping agent, a flame retardant, a crystallization nucleating agent, an antiblocking agent, an antifog additive as needed. Known additives such as mold release agents, pigments, organic or inorganic fillers, neutralizing agents, lubricants, disintegrating agents, metal deactivators, antifouling agents, antibacterial agents or other resins, thermoplastic elastomers, etc., within the scope of not impairing the effect of the invention. can do.

In addition, commercially available resins such as Dyrac D332 manufactured by Nova Chemicals, Dyrac D232, Dainippon Ink & Chemicals Co., Ltd. Ryu Rex A14, Ryu Rex A15, and PN-177 manufactured by CHI MEI are also vinyl aromatic resins of the present invention. It can be used suitably as.

Process of obtaining disc film

The method of obtaining the raw film in which the cyclic olefin resin layer (A layer) and the vinyl aromatic resin layer (B layer) were laminated is a laminated film forming by coextrusion. Specifically, a coextrusion T die method, a coextrusion inflation method, a coextrusion lamination method, etc. are mentioned. In this invention, the laminated optical film which consists of two layers of A-layer / B layer, the laminated optical film which consists of three layers of A layer / B layer / A layer, and the laminated optical consisting of three layers of B layer / A layer / B layer. The film is preferably used from the standpoint of production efficiency, strength, optical characteristics, and phase difference control. A laminated optical film composed of two layers is more preferable in optical characteristics (transparency) and phase difference control, and a laminated optical film composed of three layers is more preferable in preventing bending of the film and obtaining mechanical strength.

The extrusion temperature in the coextrusion method is appropriately selected so that the resin has a melt viscosity suitable for extrusion film formation, but both A and B layers are preferably 200 to 350 ° C, more preferably 230 to 300 ° C, and more preferably. Is 240 to 280 ° C. The temperature difference between the extrusion temperature of the layer A and the extrusion temperature of the layer B is such that when both resins are in contact with each other in the T die or in the feed block, the melt viscosity is excessively changed due to temperature change, so that the moldability does not deteriorate. Preferably it is 50 degrees C or less, More preferably, it is 30 degrees C or less, More preferably, it is 20 degrees C or less. The difference in the melt viscosity of the resin constituting the A layer and the B layer is preferably within 5 times, more preferably within 3 times, even more preferably in order to secure moldability, especially the uniformity of the thickness of each layer. Within 2 times.

Since the cyclic olefin resin and vinyl aromatic resin used by this invention are excellent in mutual adhesiveness, an adhesive layer and an adhesion layer are provided between a film layer, and reverse adhesion processing, such as a corona treatment, a plasma treatment, and a primer treatment, is performed. There is no need to do it. By thermal fusion by co-extrusion, sufficient adhesive strength can be obtained in the state which A layer and B layer directly contacted. Moreover, even after extending | stretching process, the adhesiveness of A-layer and B-layer is maintained favorable.

It is preferable that the disk film obtained is uniform in both the width direction and the longitudinal direction. Thickness fluctuation causes a phase difference fluctuation of the laminated optical film obtained, and impairs the uniformity of the display when it is assembled to a liquid crystal display device. Therefore, it is preferable that the number of die lines (longitudinal stripes resulting from scratches of T die lip, etc.), cross marks (periodic thickness fluctuations in the length direction), etc., which cause thickness variations are small. . Moreover, it is preferable that there are few gels, foreign substances, etc. which cause display defects, such as a bright point and light leakage, as a point defect. These can be suppressed, for example, by the use of an extruder with a polymer filter, optimization of the residence time of the molten resin, reduction of pulsation of the gear pump, polishing or surface treatment of the T die lip, smoothing of the transfer roll, peeling roll, surface treatment and the like. Can be. The thickness distribution of each layer in the raw film is preferably within ± 10%, more preferably within ± 5%, particularly preferably within ± 2%.

Stretch  fair

The laminated optical film of this invention which has a function as retardation film can be manufactured by extending-processing the said raw film. As a method of stretching a laminated optical film, a conventionally known method can be applied, but uniaxial stretching in a direction perpendicular to the film longitudinal direction, that is, in the width direction, is preferably used. Specifically, the method of uniaxially stretching in the width direction using a tenter is preferable. By doing so, the outstanding retardation characteristic of this invention can be expressed.

In the stretching step in the production method of the present invention, the stretching temperature is preferably determined based on Tg (TgA) of the cyclic olefin resin and Tg (TgB) of the vinyl aromatic resin in adjusting the phase difference. Specifically, the range of (lower values in TgA and TgB) to 10 (° C) to (higher values in TgA and TgB) + 30 (° C), preferably (lower values in TgA and TgB) ) -5 (° C) to (the higher value in TgA and TgB) +20 (° C).

In addition, it is preferable that the relationship between TgA and TgB satisfy the following formula (iv).

<Equation iv>

| TgA-TgB | ≤20 (° C)

The value of the above formula iv is more preferably | TgA-TgB | ≤15 (° C), more preferably | TgA-TgB | ≤12 (° C), particularly preferably | TgA-TgB | ≤10 ( ℃).

By making stretching temperature, TgA, and TgB into the said range, the phase difference of each of A-layer and B-layer can be controlled simultaneously by extending | stretching, and the characteristic made into the objective of laminated optical film (Equation (i), (ii), (iii) And characteristics represented by the equation (v) can be easily obtained. Thereby, a liquid crystal display device with high contrast ratio and small color shift when the screen is viewed from the inclined direction can be realized. Furthermore, the laminated optical film which is excellent in durability at high temperature can be obtained.

In addition, it is preferable that both TgA and TgB are 110 degreeC or more, More preferably, it is 110-200 degreeC, Especially preferably, it is 120-170 degreeC, in order to ensure thermal stability and extending | stretching workability.

In the manufacturing method of this invention, a draw ratio is 1.1 to 10 times normally, Preferably it is 1.2 to 7 times, More preferably, it is 1.3 to 5 times. In particular, the film is preferably stretched 1.3 to 5 times in uniaxial stretching, which is uniaxially stretched in the straight direction with respect to the film longitudinal direction. By transverse uniaxial stretching, since the optical axis (maximum refractive index direction in surface) of a laminated optical film of this invention becomes a direct direction with respect to a film longitudinal direction, it becomes possible to adhere | attach a laminated optical film and a polarizer by roll-to-roll, and productivity improves. do. By setting the stretching ratio in the above range, the optical axis, retardation value, NZ coefficient, or distribution in the film plane of the retardation film can be preferably controlled, and the contrast ratio is high, and the color shift when the screen is viewed from the oblique direction It is possible to realize a liquid crystal display device which is small and enables uniform screen display.

[Laminated Optical Film]

In the laminated optical film of the present invention, the layer A and the layer B are in direct contact with each other and are laminated. As a method of laminating the A layer and the B layer, in addition to the co-extrusion method described above, known methods such as film lamination molding methods such as dry lamination and coating molding methods for coating a resin solution with respect to the base resin film can be suitably used. In view of manufacturing efficiency, the coextrusion method is most preferred.

The length of the longitudinal direction of a laminated optical film becomes like this. Preferably it is 50 m or more, and it is more preferable that it is 100 m or more. Such a long film is normally handled as a film roll. Further, the width of the film is preferably 1000 mm or more, more preferably 1500 mm or more, particularly preferably 2000 mm or more.

Although the laminated optical film of this invention is not specifically limited, The film thickness is 10-400 micrometers normally, Preferably it is 20-300 micrometers, Especially preferably, it is 20-200 micrometers. Normal is preferred.

The smaller the variation in the thickness is, the less the variation in the phase difference value is, and the more uniform the display quality is. The range of the thickness variation of the laminated optical film is within an average value of ± 10%, preferably within an average value of ± 5%, and more preferably within an average value of ± 2%.

In addition, the laminated optical film of the present invention may be an unstretched film or an oriented film, but it is preferably an oriented film in order to satisfy the properties described in the formulas (i) to (iii) and (v). .

As for the laminated optical film of this invention, it is especially preferable to form by the manufacturing method of the laminated optical film of this invention.

Optical Properties of Laminated Optical Films

The laminated optical film of the present invention is characterized in that the measured value of the phase difference as the laminated optical film satisfies all the characteristics of the following formulas i to iii.

Equation i

R450≤R550≤R650

<Equation ii>

1.0≤R650 / R550≤1.2

<Equation iii>

70 nm≤R550≤150 nm

[In formulas i to iii, R450, R550, and R650 represent in-plane retardation of the laminated optical film at wavelengths of 450 nm, 550 nm, and 650 nm in order.]

I and ii have shown the wavelength dispersion of retardation, and i shows that it has so-called reverse wavelength dispersion which the in-plane phase difference becomes large, so that it becomes long wavelength. This is a characteristic necessary in preventing the polarization state of the light which passed the laminated optical film from changing with wavelength, and making small the color shift amount when the screen is seen from the inclination direction. The value of ii represents the degree of reverse wavelength dispersion. In order to reduce the amount of color shift and to perform good viewing angle compensation, the larger the value is, the more preferably 1.01 to 1.18, and more preferably 1.02 to 1.18. Iii represents the amount of retardation in the film plane. As a retardation film for the liquid crystal display device of VA mode, the compensation method which combined A plate and C plate is known, and in-plane retardation which functions effectively as A plate at this time is preferably 75 nm in the range shown in iii. To 145 nm, more preferably 75 nm to 140 nm. A satisfactory contrast ratio can be obtained by satisfying the above iii, and the color shift can be further reduced by satisfying the above i and ii, which contributes to further improvement in the contrast ratio when viewed from the oblique direction.

Moreover, in order to acquire uniformity of display quality, it is preferable that the variation of the phase difference according to a place is small in both the width direction and the longitudinal direction of a film. The range of variation of R650 / R550 of ii is preferably within ± 0.04, more preferably within ± 0.03, particularly preferably within ± 0.02. The range of variation of R550 in iii is preferably within ± 7 nm, more preferably within ± 5 nm, particularly preferably within ± 3 nm.

Similarly, in order to obtain uniformity of display quality, it is preferable that the variation of the optical axis according to the place is also smaller, and based on the film width direction orthogonal to the film length direction, preferably within ± 2 °, more preferably ± Within 1 °, more preferably within ± 0.7 °, particularly preferably within ± 0.5 °.

Moreover, it is preferable that the laminated optical film of this invention satisfy | fills following formula (v).

<Equation v>

1.0≤NZ≤3.0

[Wherein, NZ is a coefficient expressed by NZ = (nx−nz) / (nx−ny) and a value at a wavelength of 550 nm, where nx is the maximum refractive index in the laminated optical film plane, ny represents the refractive index of the direction orthogonal to nx in a laminated optical film plane, nz represents the refractive index of the laminated optical film thickness direction orthogonal to nx and ny, provided that the average refractive index of a laminated optical film is N _ave , N _ave = (nx + ny + nz) / 3, where N _ave is a weighted average of the average refractive indices of the A and B layers in the laminated optical film by the thickness ratio.]

The said v is a numerical value called NZ coefficient, and is a numerical value which showed the balance of the in-plane phase difference and thickness direction phase difference of a laminated optical film. In order to calculate the NZ coefficient, the in-plane retardation of the laminated optical film and the inclination direction retardation (typically, the value when incident from the polar angle of 40 degrees at the slow axis inclination) are measured and numerically calculated using the film total thickness and the film average refractive index. , nx, ny, and nz are obtained and determined as NZ = (nx-nz) / (nx-ny) from it. However, in the case of the laminated optical film of the present invention, since the average refractive indices of the A layer and the B layer are different from each other, N _ave cannot be measured and obtained directly.

Therefore, in this invention, the average refractive index N _ave of a laminated optical film is made into the value which weighted averaged each average refractive index of A-layer and B-layer conveniently. That is, when the average refractive index of the A layer is N _ave A, the thickness is dA (μm), and the average refractive index of the B layer is N _ave B and the thickness is dB (μm), N _ave = (dA × N _ave A + dB NZ is determined by numerically calculating nx, ny, and nz as x N _ave B) / (dA + dB).

The thickness dA, dB of each layer is obtained by peeling each layer to measure the thickness of each layer with a contact micrometer, microscopic observation of the cross section of the laminated optical film, or known non-contact measuring methods such as optical interference film thickness measurement. It is measured using the device. Among them, optical coherence film thickness measurement is preferable from the viewpoint that the measurement accuracy is good, non-destructive, on-line, or off-line.

In addition, when there are two or more layers A and / or B, respectively, for example, in the case of a three-layer structure like A-layer / B-layer / A-layer, dA is the value which summed the thickness of A-layer two or more layers, dB is the sum total of the thicknesses of two or more layers B layers.

The NZ coefficient is preferable because the one closer to 1 becomes closer to the positive A plate, and the contrast ratio is improved in accordance with the compensation method combining the A plate and the C plate, which is the compensation method for the VA liquid crystal. Preferably it is 1.0-2.5, More preferably, it is 1.0-2.0. In addition, films with NZ coefficients less than 1 do not have reverse wavelength dispersion.

Optical properties of each layer (in-plane Phase difference )

A layer and B layer which comprise the laminated optical film of this invention have preferable phase difference value and phase difference wavelength dispersion property, respectively. However, in the laminated state, since the retardation of each of A and B layers alone cannot be measured, the retardation is measured separately by separating the A and B layers from the laminated optical film, or the A and B layers are formed. The retardation value of the A layer and the B layer is calculated from the retardation wavelength dispersion of the polymer and the retardation wavelength dispersion of the laminated optical film, or the film of only the A layer and the film of the B layer alone are stretched under the same conditions as the laminated optical film, and separately By measuring a phase difference, the characteristic of each layer can be confirmed. When in-plane retardation of layer A at wavelengths of 450 nm and 550 nm is set to R450A and R550A, and in-plane retardation of layer B at wavelengths of 450 nm and 550 nm is set to R450B and R550B, each layer satisfies the following conditions vi to x. Is adjusted to.

Equation vi

R450A / R550A≤1.04

[Equation vii]

200 nm≤R550A≤400 nm

[Equation viii]

1.04 <R450B / R550B

[Equation ix]

100 nm≤R550B≤300 nm

[Equation x]

R550A> R550B

By satisfying the above formulas vi to x by the A and B layers, the above formulas i to iii are satisfied as the laminated optical films, thereby reducing the color shift when the liquid crystal display device is viewed from the inclined direction, and simultaneously reducing the contrast ratio. It becomes possible to improve. In addition, since the A- and B-layers have different intrinsic birefringence negatives and positives, when the A-layer and the B-layer are simultaneously drawn as the laminated optical film, the maximum refractive index directions of the A-layer and the B-layer are perpendicular to each other. Therefore, in-plane retardation cancels each other, and in-plane retardation R550 of the laminated optical film is represented by R550A-R550B. From said formula (x), the optical axis of a laminated optical film becomes a direction orthogonal to a film longitudinal direction, roll-to-roll adhesion with a polarizer becomes possible, and productivity of a polarizing plate improves.

By using the manufacturing method of the laminated optical film of the present invention, by stretching in the film width direction at the stretching temperature and the stretching ratio described above, each layer can satisfy the above formulas vi to x by one stretching treatment, and at the same time The above formulas i to iii may be satisfied as the whole optical film. For this reason, the manufacturing method of the laminated optical film of this invention is very excellent in productivity.

Equations vi and viii represent wavelength dispersion of the phase difference of each layer. The R450A / R550A of the A layer is smaller than the R450B / R550B of the B layer, and the wavelength dispersion of the A layer is flat wavelength dispersion that does not change very much for each wavelength, or reverse wavelength dispersion in which the phase difference increases as the wavelength increases. In contrast, the wavelength dispersion of the B layer is so-called positive wavelength dispersion in which the phase difference becomes smaller as the wavelength becomes larger than that of the A layer. By satisfy | filling this characteristic by A-layer and B-layer, when a phase difference is canceled in A-layer and B-layer, a laminated optical film satisfy | fills the characteristic of said Formula (i) and (ii).

In addition, when there are two or more layers A and / or B, respectively, for example, in the case of a three-layer structure like A / B / A layers, R450A and R550A add up the phase difference between two or more A layers. The values, R450B and R550B, are the sum of the phase differences of two or more B layers.

In addition, it is preferable for the layer A and the layer B to have less variation in the phase difference depending on the place in order to obtain uniformity of display quality. The range of variation of vi and viii is preferably within ± 0.03, more preferably within ± 0.02, particularly preferably within ± 0.01. The range of variation of R550A and R550B represented by vii and ix is preferably within ± 7 nm, more preferably within ± 5 nm, particularly preferably within ± 3 nm.

In addition, it is preferable that the optical axis variation of each layer according to the place is small in order to obtain uniformity of display quality. The optical axis of the layer A is preferably within ± 2 degrees, more preferably within ± 1 degree, even more preferably within ± 0.7 degree, particularly preferably within ± 0.5 degree, based on the film width direction. The optical axis of the layer B is preferably within ± 2 degrees, more preferably within ± 1 degree, even more preferably within ± 0.7 degree, particularly preferably within ± 0.5 degree, based on the film length direction.

In addition, in order to obtain uniformity of display quality, it is preferable that the variation in the phase difference decreases in the case where the thickness variation according to the place is small in both A and B layers. The variation range of dA and dB is within an average value of ± 10%, preferably within an average value of ± 5%, and more preferably within an average value of ± 2%, as in the range of the thickness variation of the whole laminated optical film.

Although there is no restriction | limiting in particular if the thickness ratio of A-layer and B-layer is in the preferable range with the optical characteristic of each layer and the laminated optical film whole, Specifically, when controlling a phase difference, a predetermined phase difference is carried out by one horizontal stretching process specifically ,. In order to express, Preferably, the thickness ratio of A-layer is 20 to 90% of the whole laminated optical film, More preferably, it is 30 to 80%, More preferably, it is 40 to 80%. (When two or more layers A and / or B exist, respectively, the thickness of each layer is summed and represented by the thickness ratio with respect to the whole laminated optical film of all A layers.)

Similarly, in order to obtain uniformity of display quality, it is preferable that the variation of NZ according to the place is small. The variation range of NZ is within an average value of ± 0.3, preferably within an average value of ± 0.2, more preferably within an average value of ± 0.1.

In addition, in order for NZ coefficient of the laminated optical film of this invention to satisfy said Formula (v), there exists a range of preferable NZ coefficient in A layer and B layer which comprise a laminated optical film, respectively. However, in the laminated state, since the NZ coefficients of the A and B layers alone cannot be determined, the A and B layers are separated from the laminated optical film, and the phase difference is measured separately to obtain the NZ coefficient, or the film of the A layer only. And the film of only the B layer are stretched under the same conditions as the laminated optical film, and the phase difference is measured separately to obtain an approximate NZ coefficient of each layer. If the NZ coefficient of the A layer is NZA and the NZ coefficient of the B layer is NZB, the following equations xi and xii are adjusted.

[Equation xi]

1.0≤NZA≤1.7

[Equation xii]

-1.0≤NZB≤0

[In formula (xi), NZA is a coefficient represented by NZA = (nxA-nzA) / (nxA-nyA), and is a value at a wavelength of 550 nm. Where nxA represents the maximum refractive index in the plane of the A layer, nyA represents the refractive index in the direction orthogonal to nxA within the plane of the A layer, and nzA represents the refractive index in the thickness direction of the A layer orthogonal to nxA and nyA. _ave A = (nxA + nyA + nzA) / 3. In the formula (xii), NZB is a coefficient represented by NZB = (nxB-nzB) / (nxB-nyB), and is a value at a wavelength of 550 nm. Where nxB represents the maximum refractive index in the plane of the B layer, nyB represents the refractive index in the direction orthogonal to nyB within the plane of the B layer, and nzB represents the refractive index of the thickness direction of the B layer orthogonal to nxB and nyB. _ave B = (nxB + nyB + nzB) / 3

Equation (xi) corresponds to a phase difference expressed when the cyclic olefin resin layer is laterally stretched, and nxA is the stretching direction, that is, the film width direction, and nyA is perpendicular to the stretching direction, that is, the film length direction. The refractive ellipsoid is generally called a positive A plate. The above equation (xii) corresponds to a phase difference expressed when the vinyl aromatic resin layer is laterally stretched, and nxB is orthogonal to the stretching direction, that is, the film length direction and nyB is the stretching direction, that is, the film width direction. Refractive index ellipsoids are generally referred to as negative A plates. NZ of a laminated optical film cannot be obtained by simple calculation from NZA and NZB, and is related as a result of the change of the polarization state in A layer and the change of the polarization state in B layer by Poincare sphere display.

NZA and NZB have a preferred range, preferably (NZA + NZB) /2=0.1 to 0.8, more preferably (NZA + NZB) /2=0.2 to 0.8, still more preferably (NZA + NZB) /2=0.3 to 0.7. Since NZA and NZB satisfy this range, the reverse wavelength dispersion property of the laminated optical film is exhibited even when viewed from any direction, and the problem that the predetermined phase difference is not obtained due to the optical axis shift of each layer even when viewed from any direction does not occur. This leads to an improvement of panel characteristics by reducing color shift. In addition, the smaller the NZA leads to the improvement of the panel characteristics, preferably 1.0 to 1.6, more preferably 1.0 to 1.5. At the same time, the larger the NZB leads to the improvement of the panel characteristics, preferably -0.6 to 0, more preferably -0.5 to 0. By setting the NZ coefficient of each layer to the above range, it is possible to have a predetermined phase difference even when observed from the oblique direction, thereby reducing the color shift in the oblique viewing angle of the liquid crystal display device and at the same time improving the contrast ratio.

In addition, in order to obtain uniformity of display quality, it is preferable that both NZA and NZB have less variation depending on the place. The fluctuation ranges of NZA and NZB are preferably within ± 0.2, more preferably within ± 0.1, respectively.

[Polarizing Plate]

It is preferable that the polarizing plate of this invention has the laminated optical film of this invention which has a function as a retardation film in at least one surface, and is a structure which laminated | stacked the laminated optical film of the said invention on at least one surface of a polarizer (polarizing film). Do. As a polarizer which comprises the polarizing plate of this invention, dyeing by the dichroism substance containing iodine, a dichroic dye, etc. is carried out in the film containing polyvinyl alcohol (PVA), the polymer which formed a part of PVA, etc., for example. It is a film obtained by performing a process, an extending | stretching process, a crosslinking process, etc. in a suitable order or method, and when it enters natural light, it becomes linearly polarized light and is transmitted. In particular, light has a high transmittance and excellent polarization degree is preferably used.

Although the thickness of the polarizer which comprises a polarizing plate generally uses 5-80 micrometers preferably, it is not limited to this in this invention. Moreover, as a polarizer, another thing can also be used as long as it expresses the same characteristic other than the said PVA system film. For example, the film containing the cyclic olefin resin may be subjected to dyeing treatment, stretching treatment, crosslinking treatment, etc. in an appropriate order or method, or may be a coating orientated solution of a dichroic substance, or a wire grid. It may be a type polarizer.

Usually, although a polarizing plate consists of a polarizer, a retardation film, and a protective film, in this invention, as a retardation film which comprises a polarizing plate, a laminated optical film is bonded to at least one surface of a polarizer through an adhesive agent or an adhesive, and is used. The laminated optical film may be bonded to the polarizer on the A layer side, or may be bonded to the polarizer on the B layer side. Since such a polarizing plate is excellent in properties, such as heat resistance, moisture resistance, and chemical resistance, and has a sufficient function also as a protective film, the laminated optical film of this invention which has a function as a retardation film is laminated on a polarizer. The protective film may not be laminated separately on the surface. When the polarizing plate of this invention is the structure in which the laminated optical film of this invention which has a function as a retardation film was laminated | stacked only on one side of a polarizer, the other side of a polarizer is triacetyl cellulose (TAC), cyclic olefin, for example. Known protective films such as a resin film and an acrylic resin film may be laminated.

Bonding of the laminated optical film and polarizer of this invention, bonding of a protective film, and a polarizer can be manufactured suitably by bonding each layer through well-known adhesives and adhesives, such as a pressure sensitive adhesive, a thermosetting adhesive, and a photocurable adhesive. As an adhesive and an adhesive agent, what is excellent in transparency is preferable, Specifically, adhesives, such as a natural rubber, synthetic rubber, a vinyl acetate / vinyl chloride copolymer, a polyvinyl ether, polyvinyl alcohol, an acrylic resin, a modified polyolefin resin; Curable adhesive which added hardening | curing agents, such as an isocyanate group containing compound, to the said resin which has functional groups, such as a hydroxyl group and an amino group; Adhesive for dry laminates based on polyurethane; Synthetic rubber adhesives; And epoxy adhesives.

Moreover, it is preferable that the polarizing plate of this invention further has 1 or more types chosen from an antireflection layer and an antiglare layer, and it is preferable to provide it in the outer side of the protective film surface on the opposite side to a polarizer.

These layers can be formed by coating a thermosetting resin composition or a photocurable resin composition with a known coating method such as gravure coating, die coating, slot coating, and drying as necessary, followed by curing. These layers can also be provided directly on a protective film, can be provided on it using a base film, and can also be formed by bonding the said base film to a protective film. Moreover, the said layer may be formed before bonding a protective film or a base film to a polarizer, and the said layer may be formed after bonding to a polarizer.

The antireflection layer usually includes a low refractive index layer, and may have a laminated structure of a low refractive index layer and a high refractive index layer in order to increase antireflection performance, or may further have a hard coating layer to secure scratch resistance. have. The lamination order is preferably laminated in the order of the hard coating layer / high refractive index layer / low refractive index layer from the side close to the protective film. If necessary, a medium refractive index layer may be provided between the low refractive index layer and the high refractive index layer, or between the hard coating layer and the high refractive index layer. These layers may be formed by sputtering, vapor deposition, or the like, but are preferably formed by coating of the curable composition as described above.

As a composition for forming a low refractive index layer and a high refractive index layer, a well-known curable composition is mentioned. For example, the binder resin may contain at least one epoxy resin, phenol resin, melamine resin, alkyd resin, cyanate resin, acrylic resin, polyester resin, urethane resin, siloxane resin, or the like. The composition for forming the low refractive index layer contains a fluorine-containing compound, and the composition for forming the high refractive index layer includes inorganic particles having high refractive index, such as metal oxide particles such as silica, alumina, titania, zirconia, ceria, scandia, and magnesium fluoride. It contains.

The refractive index and the thickness of the low refractive index layer and the high refractive index layer are used in a known range. In order to enhance the antireflection effect, the refractive index (average refractive index at 25 ° C. and a wavelength of 589 nm) of the low refractive index layer is preferably 1.45 or less. The thickness of the low refractive index layer is preferably 50 to 300 nm. The refractive index of the high refractive index layer (average refractive index at 25 ° C. and a wavelength of 589 nm) is preferably 0.05 or more larger than the refractive index of the low refractive index layer, and preferably 50 to 10,000 nm in thickness.

As the constituent material of the hard coat layer, known materials can be used. As such a material, 1 or more types, such as a siloxane resin, an acrylic resin, a melamine resin, an epoxy resin, can be mentioned, Inorganic particle | grains, such as a metal oxide, may be contained. In addition, a hard coat layer may have an effect as an anti-glare layer mentioned later.

In addition, the thickness of the hard coat layer is not particularly limited, but is preferably 2 to 10 m.

As an anti-glare layer, the layer which expresses anti-glare property by having an unevenness | corrugation on a layer surface is used normally, and the layer whose center line average roughness of a surface is 0.1-1.0 micrometer is preferable. As the composition for forming the antiglare layer, a curable composition containing organic particles and / or inorganic particles is preferably used. As binder resin used for a curable composition, the binder resin of the curable composition used for formation of the antireflection film mentioned above can be used. As preferable anti-glare property, the haze (Haze) of the said layer is 5-65%, and the total light transmittance is 80-98%.

[Liquid crystal display device]

The liquid crystal display device of the present invention has the polarizing plate of the present invention, and preferably has the polarizing plate of the present invention. Since the liquid crystal display device of the present invention has a laminated optical film or a polarizing plate having a high contrast ratio when the screen is viewed from the inclined direction, a small amount of color shift when the screen is viewed from the inclined direction, and small optical unevenness, the display is uniform. At the same time, it has excellent durability to withstand long-term use in harsh environments and less external light.

Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. In addition, in the following Examples and comparative examples, "part" and "%" mean "weight part" and "weight%" unless there is particular notice. In addition, room temperature is 25 degreeC.

In the following Examples and Comparative Examples, various measurements and evaluations were performed as follows.

[Polymerization reaction rate]

The weighed polymerization reaction solution was put into an aluminum manufacturing container, heated with a hot plate heated at 300 ° C until constant temperature, and residual monomer and solvent were removed, and then the remaining polymer weight was measured to determine the theoretical amount of polymer produced. The reaction rate was calculated | required from ratio.

[Hydrogenation rate]

The nuclear magnetic resonance spectrometer (NMR) was used by Bruker AVANCE500, and ¹ H-NMR was measured using d-chloroform as a measuring solvent. After the composition of the monomer was calculated from the integral values of the vinylene group of 5.1 to 5.8 ppm, the methoxy group of 3.7 ppm, and the aliphatic proton of 0.6 to 2.8 ppm, the hydrogenation rate was calculated.

[Glass Transition Temperature (Tg)]

It measured on the conditions of the temperature increase rate of 20 degree-C / min according to Japanese Industrial Standard K7121 using the differential scanning calorimeter (The Seiko Instruments company make, brand name: DSC6200).

[Weight Average Molecular Weight (Mw) and Molecular Weight Distribution (Mw / Mn)]

Gel permeation chromatography (Tosoh Co., Ltd. HLC-8220GPC, column: Tosoh Co., Ltd. guard column H _XL- H, TSK gel G7000H _XL , TSK gel GMH _XL 2, TSK gel G2000H _XL sequentially connected, solvent: Tetrahydrofuran, flow rate: 1 mL / min, sample concentration: 0.7-0.8 weight%, injection | pouring quantity: 70 microliters, measurement temperature: 40 degreeC, a detector: RI (40 degreeC), a standard substance: TSK Standard made by Tosoh Corporation Polystyrene) to determine the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn). In addition, said Mn is a number average molecular weight.

Logarithmic viscosity

The logarithmic viscosity was measured at a sample concentration of 0.5 g / dL and a temperature of 30 ° C. in chlorobenzene, using a Ubbelohde viscometer.

[thickness]

The cross section of the laminated optical film was measured by observing with an optical microscope. When the cross section is unsuitable for microscopic observation, the cross section is embedded in an epoxy resin, sliced using a microtome RV-240 manufactured by Yamato Kouki Co., Ltd., and the cross section is made clear and observed with an optical microscope. It was measured by.

[Phase difference]

It measured using the automatic birefringence meter (Oji Keisukukiki Co., Ltd. make, KOBRA-21ADH). In-plane retardation R450, R550, and R650 at wavelengths of 450 nm, 550 nm, and 650 nm were obtained by regression calculations of the measured values at wavelengths of 478.8 nm, 546.0 nm, 629.3 nm, and 747.3 nm by the Kosi equation. NZ coefficient was calculated | required from the in-plane phase difference and the slow-axis inclination inclination direction phase difference, film thickness, and film average refractive index from 40 degrees of polar angles.

[Group transmittance, polarization degree]

The single transmittance and polarization degree of the polarizing plate were measured using Nippon Bunko Corporation V-7300.

[Measurement of Contrast Ratio, etc. of Liquid Crystal Display]

Using "EZ Contrast-XL88" manufactured by ELDIM Co., Ltd., the brightness, viewing angle, contrast ratio, and color shift of the liquid crystal panel were measured in a dark room having an illuminance of 11x or less.

Adhesion Between Laminated Optical Film Layers

Adhesion was confirmed by the method of sticking a laminated optical film to a glass plate with a double-sided tape, putting a cutter blade between each layer, and peeling, and evaluated on the following references | standards.

A: A cutter blade does not enter between layers, and neither peels.

B: Although a cutter blade enters between layers and can form a peeling point, it does not peel continuously.

C: A cutter blade enters between layers, and it peels continuously from the peeling location.

[Adhesion of Anti-reflection Layer and Anti-glare Layer]

Using the cellophane tape ("CT24", Nichiban Co., Ltd. product), the checkerboard peeling test was performed by the method of JIS-D0202, and the following references | standards evaluated.

A: The number of remaining masses is 100 masses among 100 masses.

B: The number of remaining masses is more than 90 masses out of 100 masses.

C: Number of remaining masses is less than 90 masses among 100 masses.

[Environmental Test (Phase Difference)]

About the laminated optical film manufactured, 500 hours at 95 degreeC as a dry heat test, 85 hours as a wet heat test, 500 hours at 85% of a relative humidity, 30 minutes at -40 degreeC and 30 minutes at 85 degreeC as a heat shock test. It carried out under three conditions of 200 cycles as one cycle, and measured the change amount (%) of in-plane phase difference before and behind, and evaluated by the following references | standards.

A: The amount of change in phase difference is within ± 2% in all three conditions, and there is no change in appearance.

B: The amount of change in phase difference is within ± 3% of all three conditions, and there is no change in appearance.

C: The amount of change in phase difference exceeds ± 3% under either condition. Or visual changes, such as deformation | transformation, whitening, a crack, and peeling between layers, are seen visually.

[Environmental test (change of coating)]

About the protective film provided with the antireflection layer and the glare-proof layer, under the said 3 conditions, the change of the external appearance of the said layer and the presence or absence of interlayer peeling were examined before and behind a test, and the following references | standards evaluated.

A: There is no change of appearance in all 3 conditions.

B: Color change, such as whitening and yellowing, is seen.

C: The apparent appearance change, such as deformation | transformation, a crack, and peeling between layers is seen visually.

[reflectivity]

The surface without the antireflection layer of the protective film (before bonding with the polarizer or peeled off from the polarizer) provided with the antireflection layer is coated with black spray, and the spectral reflectance measuring device (large sample chamber integrating sphere accessory 150-09090 is attached). The built-in spectrophotometer U-3410 and the Hitachi Seisakusho Co., Ltd.) measured and evaluated the reflectance in the range of 380-780 nm of wavelengths at the reflection prevention layer side. Specifically, the reflectance of the antireflective laminate (antireflection film) was measured in the range of 380 to 780 nm based on the reflectance in the vapor deposition film of aluminum as a reference (100%).

Haze and Total Light Transmittance

Haze and total light transmittance are measured by the method of JISK7105 using the haze meter HZ-2 (made by Suga Shikeki Co., Ltd.) about the protective film of the state which peeled from the polarizing plate before bonding with a polarizer. It was.

Synthesis Example 1 Synthesis of Cyclic Olefin-Based Resin (A1)

215 parts of 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1, ¹⁰ ] -3-dodecene, 35 parts of bicyclo [2.2.1] hept-2-ene, 18 parts of 1-hexene (molecular weight regulator) and 750 parts of toluene (solvent for ring-opening polymerization reaction) were put into the reaction container which carried out the nitrogen substitution, and this solution was heated at 60 degreeC. Next, 0.62 parts of toluene solution of triethylaluminum (1.5 mol / l) as a polymerization catalyst, and tungsten chloride (t-butanol: methanol: tungsten = 0.35 mol) modified with t-butanol and methanol were added to the solution in the reaction vessel. 3.7 parts of a toluene solution (concentration 0.05 mol / l) of 0.3 mol: 1 mol) was added, and this solution was heat-opened-polymerized by stirring at 80 degreeC for 3 hours, and the ring-opening polymer solution was obtained. The polymerization conversion rate in this polymerization reaction was 97%, and the logarithmic viscosity measured in 30 degreeC chloroform about the obtained ring-opening polymer was 0.75 dl / g.

1,000 parts of the ring-opened polymer solution thus obtained were put into an autoclave, and 0.12 parts of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening polymer solution, and the hydrogen gas pressure was 100 kg / cm 2. Under the condition of a temperature of 165 ° C, the mixture was heated and stirred for 3 hours to carry out a hydrogenation reaction. After cooling the obtained reaction solution (hydrogenated polymer solution), hydrogen gas was discharged. This reaction solution was poured into a large amount of methanol, the coagulum was separated and recovered, and dried to obtain a hydrogenated polymer (hereinafter, cyclic olefin resin (A1)).

The resin A1 thus obtained had a hydrogenation rate of 99.9%, a glass transition temperature of 125 ° C, a number average molecular weight (Mn) of 32,000, a weight average molecular weight (Mw) of 137,000, a molecular weight distribution (Mw / Mn) of 4.29, The logarithmic viscosity was 0.69 dl / g.

Synthesis Example 2 Synthesis of Cyclic Olefin-Based Resin (A2)

Tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3- dodecene and 53 parts, 8-ethylidene tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3- dodecene unit 46 And 66 parts by weight of tricyclo [4.3.0.1 ^2,5 ] -deck-3,7-diene, and the addition amount of 1-hexene (molecular weight regulator) to 22 parts, and cyclohexane instead of toluene as a solvent for the ring-opening polymerization reaction. A hydrogenated polymer (hereinafter cyclic olefin resin (A2)) was obtained in the same manner as in Synthesis example 1 except for using.

With respect to obtained resin A2, the hydrogenation rate was 99.9%, glass transition temperature (Tg) was 125 degreeC, Mn was 30,000, Mw was 122,000, molecular weight distribution (Mw / Mn) was 4.07, and logarithmic viscosity was 0.63 dl / g.

Synthesis Example 3 Synthesis of Vinyl Aromatic Resin (B1)

In a glass flask equipped with a stirrer, a condenser and a thermometer, 127.87 g (1.23 mol) of styrene, 13.33 g (0.136 mol) of maleic anhydride, 75 g of toluene as a solvent, and 1,1'-azobis (cyclohexane- as a radical initiator) 0.67 g (2.7 mmol) of 1-carbonitrile) was added, heated to 90 ° C, and reacted for 15 hours. A part of this polymerization liquid was taken out and the reaction rate was 85%. Moreover, when molecular weight was measured, it was Mw = 129,900 and Mw / Mn = 2.00.

The obtained polymerization reaction solution was diluted with tetrahydrofuran, solidified in a large amount of methanol, the polymer was recovered and purified, and dried in a vacuum dryer at 80 ° C. for 2 days. The molecular weight and logarithmic viscosity of the obtained polymer were measured, respectively. Mw = 131,910 (Mw / Mn = 1.88), logarithmic viscosity (eta) = 0.44 dL / g, and the yield were 80%. The copolymerization composition ratio determined by NMR was as input. The polymer obtained was a copolymer of styrene-maleic anhydride and a glass transition temperature of 122 ° C. Then, let the obtained vinyl aromatic copolymer (resin) be B1.

Synthesis Example 4 Synthesis of Vinyl Aromatic Resin (B4)

In a glass flask equipped with a stirrer, a condenser and a thermometer, 145.6 g (1.40 mol) of styrene, 75 g of toluene as solvent, and 0.67 g (2.7 mmol) of 1,1'-azobis (cyclohexane-1-carbonitrile) as radical initiator ) Was added, heated to 90 ° C. and reacted for 15 hours. It was 93% when a part of this polymerization liquid was taken out and the reaction rate was measured.

The obtained polymerization reaction solution was diluted with tetrahydrofuran, solidified in a large amount of methanol, the polymer was recovered and purified, and dried in a vacuum dryer at 80 ° C. for 2 days. The molecular weight and logarithmic viscosity of the obtained polymer were measured, respectively. Mw = 168,300 (Mw / Mn = 1.68), logarithmic viscosity (eta) = 0.42 dL / g, and the yield were 87%. The polymer obtained was polystyrene and the glass transition temperature was 102 ° C. Then, let the obtained vinyl aromatic copolymer (resin) be B4.

Production Example 1 Preparation of Water-Based Adhesive

250 parts of distilled water was put into a reaction container, 90 parts of butyl acrylate, 8 parts of 2-hydroxyethyl methacrylate, 2 parts of divinylbenzene, and 0.1 part of potassium oleate were added, and this was made into Teflon (registered trademark). It stirred with the stirring blade made from the) and disperse | distributed. After nitrogen-substituting the said reaction container, this system was heated up to 50 degreeC, 0.2 part of potassium persulfate was added, and superposition | polymerization was started. After 2 hours, 0.1 part of potassium persulfate was further added, the system was heated to 80 ° C, and the polymerization reaction was continued over 1 hour to obtain a polymer dispersion.

Subsequently, this polymer dispersion liquid was concentrated until the solid content concentration became 70% using the evaporator, and the water-based adhesive agent (adhesive which has a polar group) containing the aqueous dispersion of an acrylic acid ester polymer was obtained.

As for the acrylic ester polymer constituting the aqueous adhesive obtained in this way, Mn by GPC method was 69,000 and Mw was 135,000, and the logarithmic viscosity measured in 30 ° C chloroform was 1.2 dL / g.

Production Example 2 Production of Coating Solution for Hard Coating Layer

86 parts (30 parts as solid content) of methyl ethyl ketone / isopropyl alcohol dispersion liquid of the silica particle of average particle diameter 20 nm in which the surface was modified with the unsaturated group in the container which shielded the ultraviolet-ray, 65 parts of dipentaerythritol hexaacrylates, 2 5 parts of -methyl-1- [4- (methylthio) phenyl] -2-morpholino propane-1-one and 44 parts of MIBK were stirred at 50 degreeC for 2 hours, and the coating liquid for hard-coat layers of a uniform solution was obtained. After weighing 2g of this coating liquid to the aluminum dish, it dried on the hotplate at 120 hours, and weighed and calculated | required solid content, and it was 50 weight%.

Production Example 3 Preparation of Coating Solution for Low Refractive Index Layer

After fully replacing the 2 liter stainless steel autoclave with an electronic stirrer with nitrogen gas, 400 g of ethyl acetate, 53.2 g of perfluoro (propyl vinyl ether), 36.1 g of ethyl vinyl ether, and 44.0 g of hydroxyethyl vinyl ether , Lauroyl peroxide 1.00g, azo-containing polydimethylsiloxane (VPS1001 (brand name), Wako Junyaku Kogyo Co., Ltd.) 6.0 g and nonionic reactive emulsifier (NE-30 (brand name), Asahi Denka Kogyo Co., Ltd.) ) 20.0 g were added, cooled to -50 ° C. with dry ice-methanol, and oxygen in the system was removed again with nitrogen gas.

Subsequently, 120.0 g of hexafluoropropylene was added thereto, and the temperature was started. The pressure at the point where the temperature in the autoclave reached 60 ° C. was 5.3 × 10 ⁵ Pa. Thereafter, the reaction was continued under stirring at 70 ° C. for 20 hours, and the autoclave was cooled with water at the time when the pressure dropped to 1.7 × 10 ⁵ Pa to stop the reaction. After reaching room temperature, the unreacted monomer was released, the autoclave was opened, and the polymer solution of 26.4% of solid content concentration was obtained. The obtained polymer solution was thrown into methanol, and the polymer was deposited, and then washed with methanol, and dried under vacuum at 50 ° C. to obtain 220 g of hydroxyl group-containing fluorine-containing polymer.

Subsequently, in a 1-liter detachable flask equipped with an electronic stirrer, a glass cooling tube, and a thermometer, 50.0 g of the hydroxyl group-containing fluorine-containing polymer and 0.01 g of 2,6-di-t-butylmethylphenol as polymerization inhibitors And 370 g of methyl isobutyl ketones (MIBK) were thrown in, and it stirred until the hydroxyl-containing fluorine-containing polymer melt | dissolved in MIBK at 20 degreeC, and the solution became transparent and uniform.

Subsequently, 15.1 g of 2-methacryloyloxyethyl isocyanate is added to this system, and it is stirred until the solution becomes uniform, and then 0.1 g of dibutyltin dilaurate is added to initiate the reaction. The temperature was kept at 55-65 degreeC, and stirring was continued for 5 hours, and the MIBK solution of the ethylenically unsaturated group containing fluorine-containing polymer was obtained. It was 15.0 weight% when solid content of this solution was calculated | required.

5.6 g (76 g as a solid content) of the MIBK solution of the said ethylenically unsaturated group containing fluorine-containing polymer, 65.6 g (21 g as solid content) of the methyl ethyl ketone dispersion liquid of the silica particle of the average particle diameter 45 nm which modified the surface with the unsaturated group, As a photoinitiator, 3 g of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals), and 1424.4 g of MIBK are charged into a glass detachable flask with a stirrer, and at room temperature for 1 hour. It stirred and obtained the coating liquid for uniform low refractive index layers. It was 5.0 weight% when the solid content concentration of this coating liquid was calculated | required.

Production Example 4 Preparation of Coating Solution for Anti-glare Layer and Hard Coating Layer

90.0 parts of pentaerythritol triacrylate (made by Toagosei Co., Ltd., brand name "Aronix M-305" (specific gravity 1.179)), silica particle (Tosoh Silica Co., Ltd. make, brand name "nipsil E" -200 "(specific gravity 2.150)) 10.0 mass parts and 5.0 parts of photoinitiators 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals Co., Ltd. make, brand name" Irgacure 184 "), Propylene glycol mono In addition to the methyl ether, the mixture was mixed to prepare a coating liquid having a solid concentration of 30% by weight.

Production Example 1 Preparation of Polarizer

The film of roll-shaped polyvinyl alcohol (henceforth "PVA") of 120 micrometers of film thickness is continuous by the dye bath of 30 degreeC aqueous solution whose iodine concentration is 0.03 weight%, and potassium iodide concentration is 0.5 weight%. After uniaxially stretching (full stretching) in the longitudinal direction at a draw ratio of 3 times, the boric acid concentration was 5% by weight, and the potassium iodide concentration was 8% by weight in a 55 ° C crosslinking bath in an aqueous solution, and further at a draw ratio 2 times in the longitudinal direction. It uniaxially stretched (post-stretched), dried and obtained the winding-shaped polarizer.

Production Example 2 Preparation of Optical Film (Negative C Plate) and Polarizing Plate

The film roll (150 micrometers) of cyclic olefin resin (A1) obtained by the synthesis example 1 was longitudinally stretched by extending | stretching temperature of 133 degreeC, and draw ratio 1.6 times, then tenter transversely stretched by extending | stretching temperature 135 degreeC, draw ratio 2.4 times, and thickness A 68 탆 stretched film was obtained. In-plane retardation R550 = 0-2 nm of the obtained stretched film, and average Rth = 190 nm. (Rth is one of the indices indicating the thickness direction retardation, and is represented by {(nx + ny) / 2-nz} × d, where nx is the maximum in-plane refractive index at the optical film measuring point, and ny is orthogonal to nx in the plane. Refractive index in the direction of the direction, nz represents the refractive index of the stretched film thickness direction orthogonal to nx and ny, d is the film thickness (nm) at the measurement point)

This film was made to align a roll-shaped film to one side of the polarizer obtained in Production Example 1, and the two were continuously bonded using the water-based adhesive obtained in Production Example 1, and 80 µm of saponification treatment was applied to the other side of the polarizer. The film made from triacetyl cellulose (henceforth "TAC") of thickness was adhere | attached using the adhesive agent containing the PVA aqueous solution of 5% of density | concentration, and the polarizing plate (P0) was obtained. The single transmittance of the obtained polarizing plate was 42.1%, and the polarization degree was 99.9%.

Example 1

<Manufacture of laminated optical film F1>

The cyclic olefin resin (A1) pellet and the vinyl aromatic resin (B1) pellet were each dried at 100 ° C. for 5 hours using a hot air dryer for blowing dry air. These pellets were co-extruded under conditions of a melt resin temperature of 260 ° C. and a T-die opening width of 600 mm using a two-series melt extrusion molding machine having a 65 mmφ screw and a 50 mmφ screw to form an A1 layer (150 μm). The unstretched laminated optical film roll of the structure of / B1 layer (140 micrometers) was obtained.

This laminated optical film roll was tenter transversely stretched by extending | stretching temperature 128 degreeC, and draw ratio 2.0 times, and the laminated optical film (F1) of thickness 148 micrometers was obtained. The in-plane retardation of the obtained laminated optical film was R450 = 79 nm, R 550 = 90 nm, R 650 = 96 nm, and NZ was 1.65. When the adhesiveness of this laminated optical film was confirmed, adhesiveness was favorable without peeling. In addition, as a result of the environmental tests, the amount of change in phase difference was within ± 2% in all three conditions, and no change in appearance was observed.

<Production of Polarizing Plate P1 and Evaluation of Liquid Crystal Display Device>

The obtained laminated optical film (F1) is made to align the roll-shaped film with one surface of the polarizer obtained in Production Example 1 (the stretching direction of the absorption axis of the polarizer and the stretching direction of the laminated optical film are orthogonal), and vinyl aromatic The system resin layer was faced to the polarizer side, and both were continuously bonded using the water-based adhesive obtained in Production Example 1, and on the other side of the polarizer, a saponified 80 μm-thick TAC film was used as a protective film. It adhere | attached using the adhesive agent containing 5% of PVA aqueous solution, and obtained polarizing plate (P1). When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.1% and 99.9%, respectively.

In order to evaluate the characteristic of this polarizing plate, the polarizing plate and retardation film which were affixed on the front and back of the observer side of the liquid crystal panel of Samsung Electronics Co., Ltd. liquid crystal television (model number LN40R81BD) are peeled off, and it manufactures in this peeled place. The negative C plate polarizing plate P0 obtained in Example 2 was bonded to the back side, and the polarizing plate P1 was attached to the front side in the same manner as the transmission axis of the polarizing plate originally bonded, respectively, using an acrylic transparent adhesive film. At this time, both the back and front surfaces were bonded so that the retardation film (lamination optical film) of a polarizing plate might be a liquid crystal cell side.

When the contrast ratio of the liquid crystal television which has this polarizing plate was measured, it was a numerical value as high as the maximum value: 5260, the minimum value: 110 in the range of the total orientation, polar angle 0-80 degree, and the nonuniformity was not observed visually. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, it was (DELTA) u'v '= 0.03.

Example 2

<Production of Laminated Optical Film (F2)>

Except for using Dyrac D332 (styrene-maleic anhydride copolymer (maleic anhydride content 15%), Tg: 128 ° C) manufactured by Nova Chemicals as cyclic olefin resin (A1) and vinyl aromatic resin (B2). In the same manner as in Example 1, an unstretched laminated optical film roll having a configuration of an A1 layer (150 μm) / B2 layer (120 μm) was obtained. This laminated optical film roll was tenter transversely stretched by extending | stretching temperature 130 degreeC, and draw ratio 2.0 time, and the laminated optical film (F2) of thickness 136 micrometers was obtained. In-plane retardation of the obtained laminated optical film R450 = 82 nm, R550 = 92 nm, R650 = 98 nm, NZ was 1.72. When the adhesiveness of this laminated optical film was confirmed, adhesiveness was favorable without peeling. In addition, as a result of the environmental tests, the amount of change in phase difference was within ± 2% in all three conditions, and no change in appearance was observed.

<Production of Polarizing Plate P2 and Evaluation of Liquid Crystal Display Device>

Polarizing plate P2 was obtained like Example 1 except having used laminated optical film F2 instead of laminated optical film F1. When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.0% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P2 was used instead of the polarizing plate P1. The maximum orientation was 5110 and the minimum was 100 in the range between 0 and 80 degrees of polar angle. It was a high value, and no visual nonuniformity was observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.04.

<Production of Polarizing Plate P2 'and Evaluation of Liquid Crystal Display Device>

When joining a polarizer and a laminated optical film with an aqueous adhesive, it carried out similarly to the said polarizing plate P2 except having made the cyclic olefin resin layer face the polarizer side, and obtained the polarizing plate P2 '. When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.0% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P2 'was used instead of the polarizing plate P1, and the maximum orientation was 5080 and the minimum was 100 in the range between 0 and 80 degrees of polar angle. This is a high value, and no unevenness was observed with the naked eye. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.04.

Example 3

<Manufacture of laminated optical film F3>

In the same manner as in Example 1, except that DIC Corporation Lurex A14 (styrene-methacrylic acid copolymer, Tg: 129 ° C) was used as the cyclic olefin resin (A1) and the vinyl aromatic resin (B3). The unstretched laminated optical film roll of the structure of A1 layer (150 micrometers) / B3 layer (110 micrometers) was obtained. This laminated optical film roll was tenter transversely stretched by extending | stretching temperature 130 degreeC, and draw ratio 2.0 times, and the laminated optical film (F3) of thickness 130micrometer was obtained. The in-plane retardation of the obtained laminated optical film was R450 = 81 nm, R550 = 91 nm, R650 = 96 nm, and NZ was 1.74. When the adhesiveness of this laminated optical film was confirmed, adhesiveness was favorable without peeling. In addition, as a result of the environmental tests, the amount of change in phase difference was within ± 2% in all three conditions, and no change in appearance was observed.

<Production of Polarizing Plate P3 and Evaluation of Liquid Crystal Display Device>

Polarizing plate P3 was obtained like Example 1 except having used laminated optical film (F3) instead of laminated optical film (F1). When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.0% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P3 was used instead of the polarizing plate P1, and the maximum orientation was 5050 and the minimum value was 100 in the range of 0 to 80 degrees in the total orientation. It was a high value, and no visual nonuniformity was observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.04.

Example 4

<Production of Laminated Optical Film (F4)>

A non-stretched laminated optical film roll was obtained in the same manner as in Example 3 except that the laminated structure had a three-layer structure of A1 layer (75 μm) / B3 layer (110 μm) / A1 layer (75 μm). This laminated optical film roll was tenter transversely stretched by extending | stretching temperature 130 degreeC, and draw ratio 2.0 times, and the laminated optical film (F4) of thickness 130micrometer was obtained. The in-plane retardation of the obtained laminated optical film was R450 = 84 nm, R 550 = 93 nm, R 650 = 99 nm, and NZ was 1.82. When the adhesiveness of this laminated optical film was confirmed, adhesiveness was favorable without peeling. In addition, as a result of the environmental tests, the amount of change in phase difference was within ± 2% in all three conditions, and no change in appearance was observed.

<Production of Polarizing Plate P4 and Evaluation of Liquid Crystal Display Device>

Using laminated optical film F4 instead of laminated optical film F1, the polarizing plate was carried out similarly to Example 1 except the side which faces a polarizer turns into a cyclic olefin resin layer (essentially for 3-layer lamination). (P4) was obtained. When the single transmittance and polarization degree of the obtained polarizing plate were examined, they were 41.9% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P4 was used instead of the polarizing plate P1, and the maximum value was 4890 and the minimum value was 90 in the total azimuth and polar angle range of 0 to 80 degrees. It was a high value, and no visual nonuniformity was observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, it was (DELTA) u'v '= 0.05.

Example 5

<Production of Laminated Optical Film (F5)>

The structure of A2 layer (150 micrometers) / B2 layer (130 micrometers) similarly to Example 1 except having used Nova Chemicals Dirac D332 as cyclic olefin resin (A2) and vinyl aromatic resin (B2). The unstretched laminated optical film roll of was obtained. This laminated optical film roll was tenter transversely stretched by extending | stretching temperature 130 degreeC, and draw ratio 2.0 times, and the laminated optical film (F5) of thickness 133 micrometers was obtained. The in-plane retardation of the obtained laminated optical film was R450 = 82 nm, R550 = 91 nm, R650 = 96 nm, and NZ was 1.72. When the adhesiveness of this laminated optical film was confirmed, a part of layers peeled, but the material was destroyed in the middle of peeling. Moreover, as a result of the environmental tests, the amount of change in phase difference was less than ± 2% in all three conditions, and no change in appearance was observed.

<Production of Polarizing Plate P5 and Evaluation of Liquid Crystal Display Device>

Polarizing plate P5 was obtained like Example 1 except having used laminated optical film F5 instead of laminated optical film F1. When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.0% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P5 was used instead of the polarizing plate P1, and the maximum orientation was 4970 and the minimum was 100 in the range between 0 and 80 degrees of polar angle. It was a high value, and no visual nonuniformity was observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.04.

Comparative Example 1

<Production of Optical Film F6>

The film roll (150 micrometers) of A1 was obtained by extrusion molding cyclic olefin resin (A1) independently. The film roll of A1 was tenter transversely stretched by extending | stretching temperature 140 degreeC, and draw ratio 3.0 times, and the optical film (F6) of thickness 55micrometer was obtained. In-plane phase difference R450 = 121 nm, R550 = 120 nm, R650 = 119 nm of this optical film, and NZ = 1.33. In addition, as a result of the environmental tests, the amount of change in phase difference was within ± 2% in all three conditions, and no change in appearance was observed.

<Production of Polarizing Plate P6 and Evaluation of Liquid Crystal Display Device>

Polarizing plate P6 was obtained like Example 1 except having used optical film F6 instead of laminated optical film F1. When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 41.8% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P6 was used instead of the polarizing plate P1. The maximum orientation was 5160 and the minimum was 85 in the range between 0 and 80 degrees of polar angle. It was a numerical value, and no visual nonuniformity was observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.11. Since the optical film F6 does not have reverse wavelength dispersion, the value of Δu'v 'is slightly increased, and the color shift is not improved.

Comparative Example 2

<Manufacture of laminated optical film F7>

Except for using cyclic olefin resin (A2) and vinyl aromatic resin (B4), it carried out similarly to Example 1, and the unstretched laminated optical film roll of the structure of A2 layer (130 micrometers) / B4 layer (130 micrometers) Got it. This laminated optical film roll was tenter transversely stretched by extending | stretching temperature 130 degreeC, and draw ratio 2.0 times, and the laminated optical film (F7) of thickness 133 micrometers was obtained. In-plane retardation R450 = 258 nm, R550 = 255 nm, R650 = 252 nm, and NZ = 1.45 of the obtained laminated optical film. When the adhesiveness of this laminated optical film was confirmed, between layers peeled easily. Moreover, as a result of the environmental test, the amount of change of the phase difference in the dry heat test exceeded 5%, and the interlayer peeled off by the wet heat test and the heat shock test.

<Production of Polarizing Plate P7 and Evaluation of Liquid Crystal Display Device>

Polarizing plate P7 was obtained like Example 1 except having used laminated optical film F7 instead of laminated optical film F1. When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.0% and 99.9%, respectively. The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 except that the polarizing plate P7 was used instead of the polarizing plate P1, and the maximum value was 5320 and the minimum value was 5320 in the total azimuth and polar angle range of 0 to 80 degrees. It became. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, it was (DELTA) u'v '= 0.22. Since the glass transition temperature of vinyl aromatic resin (B4) used for laminated optical film (F7) was low, and when extending | stretching, a predetermined phase difference does not appear in B4 layer, and since laminated optical film does not have a preferable phase difference, front contrast The ratio is not a problem, but the contrast ratio in the oblique direction is bad, and there are many color shifts.

Comparative Example 3

<Production of Laminated Optical Film (F8)>

The film roll (150 micrometers) of A1 was obtained by extrusion molding cyclic olefin resin (A1) independently. The film roll of A1 was tenter transversely stretched by extending | stretching temperature 130 degreeC, and draw ratio 2.0 times, and the optical film of 77 micrometers in thickness was obtained. In-plane retardation R450 = 263 nm, R550 = 260 nm, R650 = 257 nm, and NZ = 1.38 of the optical film.

Subsequently, the polyimide solution for alignment films was apply | coated on the PET film with the wire bar, and it dried for 1 minute by 80 degreeC warm air, and 2 minutes by 100 degreeC warm air, and the surface of this polyimide alignment film was rubbed. The polymerizable nematic liquid crystal solution was applied onto the alignment film with a wire bar, dried at 100 ° C. for 2 minutes, and then irradiated with UV at 700 mJ / cm 2 using a high pressure mercury lamp to polymerize the polymerizable nematic liquid crystal compound. When this liquid crystal cured film was peeled from PET film and phase difference was measured, R450 = 174 nm, R550 = 165 nm, R650 = 159 nm, NZ = 1.02 and thickness were 2 micrometers.

The obtained liquid crystal cured film was bonded together on the said optical film using the acryl-type transparent adhesive film so that the optical-axis direction (maximum refractive index direction in surface) may mutually cross, and laminated optical film (F8) was obtained. The in-plane retardation of the obtained laminated optical film was R450 = 89 nm, R550 = 95 nm, R650 = 98 nm, and NZ was 3.80. Moreover, as a result of an environmental test, the amount of change of phase difference in 3 conditions was 2.3% at maximum, and the change of an external appearance was not seen.

<Production of Polarizing Plate P8 and Evaluation of Liquid Crystal Display Device>

The polarizing plate P8 was obtained like Example 1 except having made the liquid crystal hardening layer face the polarizer side using laminated optical film F8 instead of laminated optical film F1. When the single transmittance and polarization degree of the obtained polarizing plate were examined, they were 41.9% and 99.9%, respectively. When the contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 using the polarizing plate P8 instead of the polarizing plate P1, the maximum value was 4900 and the minimum value was 15 in the range between 0 and 80 degrees of polar angle. No irregularities were observed with the naked eye. Moreover, when the color shift in polar angle 0-60 degree was measured at the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.15. In F8 which laminated | stacked a liquid crystal cured film, in-plane phase difference R450, R550, and R650 become reverse wavelength dispersion, but there is no problem, but NZ coefficient is not in a preferable range by phase difference or more of a diagonal direction. Therefore, the front contrast ratio is not a problem, but the contrast ratio in the oblique direction is bad, and there are many color shifts.

[Reference Example]

The retardation film previously bonded to the liquid crystal television was peeled off from the polarizing plate, and an environmental test was carried out by the above method as a reference. As a result, the amount of change in retardation under three conditions was 5% at maximum, and the test sample was curled.

Among the above results, the evaluation results of the laminated optical film are shown in Table 1 below, and the panel characteristics before peeling off the polarizing plate in the liquid crystal television as the evaluation results of the polarizing plate and the liquid crystal display device are shown in Table 2 below.

Example 6

<Production of the antireflection layer part polarizing plate (P1-1) and evaluation of the liquid crystal display device>

On one side of the same TAC film as the protective film used in Example 1, the hard coating layer coating solution prepared in Production Example 2 was applied with a wire bar, dried at 80 ° C. for 2 minutes, and then 600 mJ / UV irradiation at 2 cm 2 was carried out to polymerize to prepare a cured film having a thickness of 4 µm. The coating solution for low refractive index layer prepared in Preparation Example 3 was further applied to the surface on which the hard coating layer was formed, dried at 80 ° C. for 2 minutes, and then polymerized by UV irradiation at 600 mJ / cm 2 using a high pressure mercury lamp. And a cured film with a thickness of 100 nm were formed to obtain an antireflection layer portion protective film. When the reflectance of the obtained protective film was measured, it confirmed that it was 2.4% or less at 380-780 nm, and there was an antireflective effect. Moreover, haze was 0.5% and the total light transmittance was 94.2%. Moreover, the adhesiveness of the antireflection layer was excellent, and as a result of the environmental tests, no change in appearance and peeling of the layer due to the antireflection layer were observed in all three conditions.

In Example 1, polarizing plate (P1-1) was obtained like Example 1 except having used the said anti-reflection layer part protective film as a protective film. Using the obtained polarizing plate (P1-1), the contrast ratio of the liquid crystal television was measured in the same manner as in Example 1, and the maximum value was 5210 and the minimum value was 105 in the total azimuth and polar angle range from 0 to 80 degrees. Was not observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, (DELTA) u'v '= 0.04. In addition, there was less reflection of external light during black display.

Example 7

<Manufacture of Polarizing Plate with Anti-glare Layer (P1-2) and Evaluation of Liquid Crystal Display Device>

The antiglare layer and the hard coat layer coating solution prepared in Production Example 4 were applied to one side of the same TAC film as the protective film used in Example 1 with a wire bar, dried at 80 ° C. for 2 minutes, and then 600 using a high pressure mercury lamp. UV irradiation was carried out at mJ / cm 2 to polymerize, a cured film having a thickness of 4 µm was formed to obtain a protective film with an antiglare layer. The haze of the obtained protective film was 25%, the total light transmittance was 93.0%, and the surface which provided the glare-proof layer had the blurring of external light (fluorescent lamp) being suppressed. In addition, the adhesion of the antiglare layer was excellent, and as a result of the environmental test, no change in appearance and peeling of the layer due to the antiglare layer were observed in all three conditions.

In Example 1, the polarizing plate (P1-2) was obtained like Example 1 except having used the said protective film with an anti-glare layer as a protective film. Using the obtained polarizing plate (P1-2), the contrast ratio of the liquid crystal television was measured in the same manner as in Example 1, and the maximum value was 5200 and the minimum value 105 in the total azimuth and polar angle range of 0 to 80 degrees. Was not observed. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, it was (DELTA) u'v '= 0.03. In addition, there was less shimmering and blurring of external light during black display.

Example 8

<Manufacture of Polarizing Plate with Anti-glare Layer (P1-4) and Evaluation of Liquid Crystal Display Device>

The laminated optical film F1 obtained in Example 1 was arranged so that a roll-shaped film was aligned with one surface of the polarizer obtained in Production Example 1 (the stretching direction, which is the absorption axis of the polarizer, and the stretching direction of the laminated optical film were orthogonal to each other). ) And the vinyl aromatic resin layer was faced to the polarizer side, and both were continuously bonded using the water-based adhesive obtained in Production Example 1. In addition, on the other side of the polarizer, the film roll (60 µm thickness) of the cyclic olefin resin (A1) obtained in Synthesis Example 1 was continuously bonded to each other using the water-based adhesive obtained in Production Example 1, and the polarizing plate (P1). -3) was obtained. When the single transmittance and polarization degree of the obtained polarizing plate were examined, it was 42.3% and 99.9%, respectively.

After coating the anti-glare layer and hard-coat layer coating liquid manufactured by the manufacture example 4 to the cyclic olefin resin film surface which is a polarizer protective film of this polarizing plate with a wire bar, and drying at 80 degreeC for 2 minutes, it uses 600 mJ using a high pressure mercury lamp. UV irradiation at / cm 2 to polymerize, a cured film having a thickness of 5 µm was prepared, to obtain a polarizing plate (P1-4) with an antiglare layer. On the surface on which the antiglare layer was formed, blurring of external light (fluorescent lamp) was suppressed. When the protective film was peeled off from the polarizing plate and evaluated as an anti-glare layer and a hard-coat layer part protective film, haze was 30% and the total light transmittance was 93.3%. Moreover, as a result of the environmental test, in all three conditions, the change of the external appearance resulting from an anti-glare layer, and peeling of a layer were not seen.

The contrast ratio of the liquid crystal television was measured in the same manner as in Example 1 using the polarizing plate P1-4 instead of the polarizing plate P1, and the maximum value was 5230 and the minimum value was 105 in the range between 0 and 80 degrees of polar angle. And no nonuniformity was observed visually. Moreover, when the color shift in polar angle 0-60 degree was measured in the azimuth angle 45 degree in black display state, it was (DELTA) u'v '= 0.03. In addition, there was less shimmering and blurring of external light during black display.

About the anti-glare layer on the surface of the polarizing plate previously bonded to a liquid crystal television, when peeled with the protective film which is a base material, and the environmental test was performed, the yellowing of the coating film was seen slightly.

The evaluation result of Examples 6-8 and the evaluation result of the polarizing plate previously bonded to the said liquid crystal television are shown in Table 3 below.

The laminated optical film and polarizing plate which concern on this invention can be used for various optical components. For example, various liquid crystal display devices such as liquid crystal televisions, liquid crystal monitors, mobile phones, car navigation systems, portable game machines, and digital information terminals, liquid crystal projectors, electroluminescent display elements, or transparent conductive films such as ITO can be installed and used for touch panels. have. Moreover, it is useful also as a near-infrared cut film used for optical systems, such as a wavelength plate and a camera, which are used for the optical system of the recording / reproducing apparatus of an optical disk.

Claims (15)

Laminating and forming a cyclic olefin resin and a vinyl aromatic resin by coextrusion to obtain a raw film in which the cyclic olefin resin layer and the vinyl aromatic resin layer are laminated; It has a process of uniaxially stretching the obtained raw film to a straight direction with respect to a film longitudinal direction, The laminated optical film which fully satisfy | fills the characteristic represented by following formula (i) -iii is obtained, The manufacturing method of the laminated optical film characterized by the above-mentioned. Equation i R450≤R550≤R650 <Equation ii> 1.0≤R650 / R550≤1.2 <Equation iii> 70 nm≤R550≤150 nm [In formulas i-iii, R450, R550, and R650 sequentially represent the in-plane retardation of the laminated optical film at wavelengths of 450 nm, 550 nm, and 650 nm.] The method for producing a laminated optical film according to claim 1, wherein the cyclic olefin resin comprises a copolymer having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2). <Formula 1>

[In formula 1, m is an integer of 1 or more, p is an integer of 0 or more, X is independently a group represented by the formula -CH = CH- or a group represented by the formula -CH ₂ CH _2- , R ¹ to R ⁴ are each independently (a) a hydrogen atom, (b) a halogen atom, (c) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, including a linking group comprising an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom, (d) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, (e) represents a polar group; (f) R ¹ and R ² , or R ³ and R ⁴ represent an alkylidene group formed by bonding to each other, R ¹ to R ^{4 which} is not involved in the bond are independently selected from (a) to (e) Being, or (g) R ¹ and R ² , R ³ and R ⁴ , or R ² and R ³ represent an aromatic or non-aromatic monocyclic or polycyclic hydrocarbon ring or heterocyclic ring formed by bonding with each other, and are not involved in the bond. R ¹ to R ⁴ are independently selected from each other (a) to (e). <Formula 2>

In Formula 2, Y is a group represented by the formula -CH = CH- or a group represented by the formula -CH ₂ CH _2- , R ⁵ to R ⁸ are each independently (a) a hydrogen atom, (b) a halogen atom, (c) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, including a linking group comprising an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom, (d) a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, (e) represents a polar group; (f) R ⁵ and R ⁶ , or R ⁷ and R ⁸ represent an alkylidene group formed by bonding to each other, and R ⁵ to R ^{8 which} are not involved in the bond are independently selected from (a) to (e) Being, or (g) R ⁵ and R ⁶ , R ⁷ and R ⁸ , or R ⁶ and R ⁷ represent an aromatic ring or a non-aromatic monocyclic or polycyclic hydrocarbon ring or heterocyclic ring formed by bonding with each other and are not involved in the above bond; R ⁵ to R ⁸ are independently selected from each other selected from the above (a) to (e)] The method for producing a laminated optical film according to claim 1, wherein the vinyl aromatic resin is a styrene- (meth) acrylic acid copolymer. The method for producing a laminated optical film according to claim 1, wherein the vinyl aromatic resin is a styrene-maleic anhydride copolymer. The method for producing a laminated optical film according to claim 1, wherein the cyclic olefin resin layer and the vinyl aromatic resin layer are in direct contact with each other. The manufacturing method of the laminated optical film of Claim 1 in which the cyclic olefin resin and vinyl aromatic resin satisfy | fill the relationship which satisfy | fills following formula (iv). <Equation iv> TgA (° C) -TgB (° C) | ≤20 (° C) [In formula, TgA represents the glass transition temperature of cyclic olefin resin, TgB represents the glass transition temperature of vinyl aromatic resin.] The manufacturing method of the laminated optical film of Claim 1 whose glass transition temperature (TgA) of cyclic olefin resin and the glass transition temperature (TgB) of vinyl aromatic resin are both 110 degreeC or more. A cyclic olefin resin layer and a vinyl aromatic resin layer directly contact and are laminated, and satisfy | fill all the characteristics of following formula (i)-iii, The laminated optical film characterized by the above-mentioned. Equation i R450≤R550≤R650 <Equation ii> 1.0≤R650 / R550≤1.2 <Equation iii> 70 nm≤R550≤150 nm [In formulas i-iii, R450, R550, and R650 sequentially represent the in-plane retardation of the laminated optical film at wavelengths of 450 nm, 550 nm, and 650 nm.] The laminated optical film according to claim 8, wherein the following expression v is satisfied. <Equation v> 1.0≤NZ≤3.0 [Wherein, NZ is a coefficient represented by NZ = (nx−nz) / (nx−ny) and a value at a wavelength of 550 nm, where nx is the maximum refractive index in the laminated optical film plane, ny is the refractive index of the direction orthogonal to nx in a laminated optical film plane, nz represents the refractive index of the laminated optical film thickness direction orthogonal to nx and ny, provided that the average refractive index of a laminated optical film is N _ave , N _ave = (nx + ny + nz) / 3, and N _ave is a weighted average of the average refractive indices of each of the cyclic olefin resin layer and the vinyl aromatic resin layer in the thickness of the laminated optical film. The laminated optical film of Claim 8 whose glass transition temperature of cyclic olefin resin and the glass transition temperature of vinyl aromatic resin are both 110 degreeC or more. It is obtained by the method of Claim 1, The laminated optical film characterized by the above-mentioned. The laminated optical film of any one of Claims 8-11 is laminated | stacked on at least one surface of a polarizer through an adhesive agent or an adhesive, The polarizing plate characterized by the above-mentioned. The polarizing plate according to claim 12, further comprising at least one layer selected from an antireflection layer and an antiglare layer. It has a polarizing plate of Claim 12, The liquid crystal display device characterized by the above-mentioned. It has a polarizing plate of Claim 13, The liquid crystal display device characterized by the above-mentioned.