JP6528380B2 - Optical film, method of manufacturing optical film, polarizing plate, and display device - Google Patents

Description

  The present invention relates to an optical film, a method of manufacturing an optical film, a polarizing plate, and a display. More particularly, the present invention relates to an optical film containing a cycloolefin resin, a polarizing plate provided with the optical film, and a display.

  A transparent resin film containing cellulose ester, polycarbonate, cycloolefin or the like is used as an optical film, mainly for an optical compensation film for liquid crystal display devices. Among them, cycloolefin resins are widely used because of their excellent transparency and moldability.

  2. Description of the Related Art In recent years, as the performance of display devices has been improved, there has been an increasing demand for optical properties and scratch resistance of optical films constituting display devices. In order to improve the performance of optical films, it is generally practiced to apply a hard coat layer to the surface of a transparent resin film.

  And the method of maintaining the optical visibility of an optical film and improving abrasion resistance is proposed by improving the adhesiveness of a cycloolefin resin and a hard-coat layer.

For example, in Patent Document 1, a hard coat layer containing an ultraviolet curable acrylic resin is provided on at least one surface of a cycloolefin film formed of a cycloolefin polymer, and the hard coat layer has an average particle diameter of 1.0 μm. By containing the organic particles of not less than 4.0 μm and the inorganic fine particles having an average particle diameter of not more than 50 nm, asperities with a ten-point average roughness (Rz) of not less than 0.1 μm and not more than 1.0 μm A method is disclosed in which the adhesion to a cycloolefin film is enhanced by forming a part and setting the static friction coefficient and the dynamic friction coefficient between the hard coat layer surface and the cycloolefin film to 0.9 or less.
However, with the configuration described in Patent Document 1, there has been a problem that the adhesion is insufficient, and the requirements for maintaining the optical visibility and improving the scratch resistance can not be satisfied.

JP, 2013-186236, A

  The present invention has been made in view of the above problems and circumstances, and the problem to be solved is an optical film having excellent adhesion between a transparent resin film and a hard coat layer, a method of manufacturing an optical film, a polarizing plate, and a display It is providing a device.

  As a result of intensive studies to solve the above problems, the present inventors contained 2 to 20% by mass of a compound represented by the following general formula (I) in a cycloolefin resin, and controlled the orientation of the compound to be transparent. It has been found that the above problems can be solved by forming a resin film, and the present invention has been made.

  In the present invention, the compound is contained in a transparent resin film, and by stretching the transparent resin film, the flatness of the compound is controlled so as to be vertically oriented with respect to the thickness direction of the transparent resin film, and transparency is achieved. In order to suppress precipitation of the compound contained in the resin film and enable formation of appropriate smoothness and uniform surface on the transparent resin film surface, the coatability of the coating liquid for hard coat layer formation on the transparent resin film plane It can be inferred that the optical film was improved, the decrease in adhesion between the transparent resin film and the hard coat layer was suppressed, and good transparency was obtained in the optical film.

（Ｒ１〜Ｒ３は、置換若しくは無置換のアリール基、又は複素環基である。；
Ｌ１〜Ｌ３は、単結合、又は炭素原子若しくは窒素原子を含む２価の連結基である。；
Ａ１〜Ａ６は、それぞれ独立に炭素原子、窒素原子、又は酸素原子である。）
２．前記一般式（ＩＩ）において、Ａ１〜Ａ６で表される６員環芳香族基がトリアジン環基であることを特徴とする第１項に記載の光学フィルム。
３．前記一般式（ＩＩ）において、Ｌ１〜Ｌ３の少なくとも一つが単結合であることを特徴とする第１項又は第２項に記載の光学フィルム。
４．前記一般式（ＩＩ）において、Ｒ１〜Ｒ３の少なくとも一つが置換若しくは無置換の芳香族炭化水素環基又は芳香族複素環基により置換されていることを特徴とする第１項から第３項までのいずれか一項に記載の光学フィルム。
５．前記透明樹脂フィルムの厚さが、４０μｍ以下であることを特徴とした第１項から第４項までのいずれか一項に記載の光学フィルム。
６．第１項から第５項までのいずれか一項に記載の光学フィルムを製造する光学フィルムの製造方法であって、
前記透明樹脂フィルムを溶液流涎法で成形することを特徴とする光学フィルムの製造方法。
７．前記透明樹脂フィルムの搬送方向に対して直交する幅手方向に延伸した後、当該幅手方向に対して４５°の斜め方向に延伸することを特徴とする第６項に記載の光学フィルムの製造方法。
８．前記幅手方向の延伸が、１．０３〜１．３０倍の範囲内で、かつ、
前記斜め方向の延伸が、１．５０〜２．５倍の範囲内であることを特徴とする第７項に記載の光学フィルムの製造方法。
９．第１項から第５項までのいずれか一項に記載の光学フィルムを備えたことを特徴とする偏光板。
１０．第９項に記載した偏光板を備えたことを特徴とする表示装置。 The above-described problems of the present invention can be solved by the following means.
1. In an optical film provided with a hard coat layer on at least one surface of a transparent resin film containing a cycloolefin resin as a main component,
The compound having a structure represented by the general formula ( II ) is contained in the range of 2 to 20% by mass with respect to the cycloolefin resin,
The in-plane retardation value Ro (550) of the transparent resin film measured with light of wavelength 550 nm is in the range of 120 to 160 nm,
Stretched so that the slow axis and the longitudinal direction of the transparent resin film are 45 °, and
An optical film characterized in that the planarity of the compound is controlled to be vertically oriented with respect to the thickness direction of the transparent resin film.

(R1 to R3 each represents a substituted or unsubstituted aryl group or a heterocyclic group;
L1 to L3 each represent a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. ;
A1 to A6 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. )
2 . The optical film according to claim 1 , wherein the six-membered ring aromatic group represented by A1 to A6 in the general formula (II) is a triazine ring group.
3 . In the general formula (II), optical film according to paragraph 1 or 2, wherein at least one L1~L3 is a single bond.
4 . In the formula (II), the first term which is characterized in that it is substituted by at least one is a substituted or unsubstituted aromatic hydrocarbon ring group or aromatic heterocyclic group R1~R3 to paragraph 3 The optical film according to any one of the above.
5 . The optical film according thickness of the transparent resin film, in any one of the first term which is characterized in that it is 40μm or less to the fourth term.
6 . It is a manufacturing method of the optical film which manufactures an optical film given in any 1 paragraph of paragraphs 1 to 5,
The method of manufacturing an optical optical film you characterized by forming said transparent resin film with a solution drooling method.
7. 7. The optical film according to claim 6, wherein the transparent resin film is stretched in a width direction orthogonal to the transport direction, and then stretched in an oblique direction of 45 ° with respect to the width direction. Method.
8. The stretching in the width direction is in the range of 1.03 to 1.30 times, and
8. The method for producing an optical film according to claim 7, wherein the stretching in the oblique direction is in a range of 1.50 to 2.5 times.
9. A polarizing plate comprising the optical film according to any one of the first term to the fifth term.
10. A display comprising the polarizing plate described in item 9.

  By the above means of the present invention, it is possible to provide an optical film having excellent adhesion between a transparent resin film and a hard coat layer, a method of producing an optical film, a polarizing plate, and a display device.

Schematic of optical film

  Hereinafter, the present invention will be described in detail. In the present application, “to” is used in the meaning including the numerical values described before and after that as the lower limit value and the upper limit value. Further, in the present invention, preferred embodiments may be arbitrarily modified and implemented without departing from the scope of the claims and the equivalents thereof.

  FIG. 1 is a schematic cross-sectional view of an optical film according to an embodiment of the present invention. As shown in FIG. 1, in one of the preferred embodiments of the optical film 1 of the present invention, the planarity of the compound 4 represented by the general formula (I) with respect to the thickness direction L of the transparent resin film 2 is It is characterized in that it is controlled to be vertically oriented.

«Optical film»
In the optical film of the present invention, a hard coat layer is provided on at least one surface of a transparent resin film containing a cycloolefin resin as a main component, and the cycloolefin resin is represented by the general formula (I) Containing a compound having the following structure in the range of 2 to 20% by mass, and the in-plane retardation value Ro (550) of the transparent resin film measured at a wavelength of 550 nm is in the range of 90 to 170 nm. Do.

<Transparent resin film>
The transparent resin film of the present invention is characterized by containing at least a cycloolefin resin and a compound having a structure represented by the general formula (I).

(Cycloolefin resin)

  As the cyclopolyolefin resin according to the present invention, the following (co) polymers may be mentioned.

〔式中、Ｒ^１〜Ｒ^４は、それぞれ独立に、水素原子、炭化水素基、ハロゲン原子、ヒドロキシ基、エステル基、アルコキシ基、シアノ基、アミド基、イミド基、シリル基、又は極性基（すなわち、ハロゲン原子、ヒドロキシ基、エステル基、アルコキシ基、シアノ基、アミド基、イミド基、又はシリル基）で置換された炭化水素基である。ただし、Ｒ^１〜Ｒ^４は、二つ以上が互いに結合して、不飽和結合、単環又は多環を形成していてもよく、この単環又は多環は、二重結合を有していても、芳香環を形成してもよい。Ｒ^１とＲ^２とで、又はＲ^３とＲ^４とで、アルキリデン基を形成していてもよい。ｐ、ｍは０以上の整数である。〕

[Wherein, R ^{1 to} R ⁴ each independently represent a hydrogen atom, a hydrocarbon group, a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amido group, an imide group, a silyl group, or a polar group ( That is, it is a hydrocarbon group substituted by a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amido group, an imide group, or a silyl group). Provided that two or more of R ^{1 to} R ⁴ may be bonded to each other to form an unsaturated bond, a monocyclic or polycyclic ring, and the monocyclic or polycyclic ring has a double bond Or an aromatic ring may be formed. An alkylidene group may be formed by R ¹ and R ² , or R ³ and R ⁴ . p and m are integers of 0 or more. ]

In the above general formula (1), R ¹ and R ³ are a hydrogen atom or a hydrocarbon group having 1 to 10, more preferably 1 to 4, particularly preferably 1 to 2 carbon atoms, and R ² and R ⁴ are hydrogen An atom or a monovalent organic group, wherein at least one of R ² and R ⁴ represents a hydrogen atom and a polar group having a polarity other than a hydrocarbon group, m is an integer of 0 to 3 and p is 0 to 3 And more preferably m + p = 0-4, still more preferably 0-2, particularly preferably m = 1 and p = 0. The specific monomer in which m = 1 and p = 0 is preferable in that the glass transition temperature of the obtained cyclopolyolefin resin is high and the mechanical strength is also excellent.

Examples of the polar group of the specific monomer include a carboxy group, a hydroxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amido group, a cyano group and the like, and these polar groups are linked groups such as a methylene group. It may be linked via Further, a hydrocarbon group in which a divalent organic group having polarity such as a carbonyl group, an ether group, a silyl ether group, a thioether group or an imino group is linked as a linking group is also exemplified as a polar group. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group or an allyloxy carbonyl group is preferable, and an alkoxycarbonyl group or an allyloxy carbonyl group is particularly preferable.

Furthermore, a monomer in which at least one of R ² and R ⁴ is a polar group represented by the formula — (CH ₂ ) n COOR, the obtained cyclopolyolefin resin has a high glass transition temperature and a low hygroscopicity, with various materials It is preferable in that it has excellent adhesion. In the above formula for the specific polar group, R is a hydrocarbon group having 1 to 12, more preferably 1 to 4, particularly preferably 1 to 2 carbon atoms, preferably an alkyl group.

Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and dicyclopentadiene.
The carbon number of the cycloolefin is preferably 4 to 20, and more preferably 5 to 12.

  In the present invention, cycloolefin resins can be used alone or in combination of two or more.

The preferred molecular weight of the cyclopolyolefin resin according to the present invention is an intrinsic viscosity [η] inh of 0.2 to 5 dl / g, more preferably 0.3 to 3 dl / g, particularly preferably 0.4 to 1.5 dl / g The polystyrene equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 8000 to 100000, more preferably 10000 to 80000, and particularly preferably 12000 to 50000, and the weight average molecular weight (Mw) Is preferably in the range of 20,000 to 300,000, more preferably 30,000 to 250,000, and particularly preferably 40,000 to 200,000.

  When the intrinsic viscosity [η] inh, the number average molecular weight and the weight average molecular weight are in the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties of the cyclopolyolefin resin, and molding as the cyclopolyolefin film of the present invention Processability is good.

  The glass transition temperature (Tg) of the cyclopolyolefin resin according to the present invention is usually 110 ° C. or higher, preferably 110 to 350 ° C., more preferably 120 to 250 ° C., particularly preferably 120 to 220 ° C. If the Tg is less than 110 ° C., it is not preferable because it is deformed by use under high temperature conditions or secondary processing such as coating and printing. On the other hand, when the Tg exceeds 350 ° C., molding becomes difficult, and the possibility of deterioration of the resin due to heat during molding becomes high.

  In the cyclopolyolefin resin, a specific hydrocarbon-based resin or a known thermoplastic resin described in, for example, JP-A-9-221577 and JP-A-10-287732 as long as the effects of the present invention are not impaired. Resin, thermoplastic elastomer, rubbery polymer, organic fine particles, inorganic fine particles, etc. may be compounded, specific wavelength dispersing agent, sugar ester compound, antioxidant, peeling accelerator, rubber particles, plasticizer, ultraviolet light An additive such as an absorbent may be included.

  As the cyclopolyolefin resin described above, commercially available products can be preferably used, and examples of commercially available products are commercially available from JSR Corporation under the trade names Arton G, Arton F, Arton R, and Arton RX. It is also commercially available from Nippon Zeon Co., Ltd. under the trade names Zeonor ZF14, ZF16, Zeonex 250 or Zeonex 280, and these can be used.

(Compound represented by general formula (I))
The optical film of the present invention is characterized by containing a compound represented by the following general formula (I) in order to improve the adhesion to the hard coat layer. Then, by stretching the transparent resin film, it is presumed that the planarity of the compound represented by the general formula (I) is oriented perpendicularly to the thickness direction of the optical film, and the oriented compound is an optical film. Precipitation of the compound contained is suppressed, formation of appropriate smoothness and a uniform surface is enabled in the transparent resin film surface, and excellent adhesiveness is obtained between the transparent resin film and the hard coat layer.

（Ｒ及びＲ‘は、置換又は無置換の６員環芳香族である。Ｌは、単結合、又は炭素原子若しくは窒素原子を含む２価の連結基である。ｎは、０〜２の整数である。）

(R and R ′ are substituted or unsubstituted 6-membered ring aromatic. L is a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. N is an integer of 0 to 2 Is)

  In the present invention, the planarity of a compound means a π-conjugated system on the same plane in the compound. Therefore, by extending the π conjugation on the same plane, the compound can obtain high planarity.

  In general, when a unsaturated bond is linked via a single bond or one or two linking hands, as in a compound represented by n = 0 to 2 in the general formula (I), π-conjugated The structure can be seen. In particular, a single bond has double bondability due to the interaction between unsaturated bonds. Electrons (π electrons) involved in π bonds of unsaturated bonds linked via a single bond or a bond are stable when they have a common π electron orbital. Therefore, they become coplanar, including single bonds or electrons that have come to be present on bonds.

  The unsaturated bond in this case is not limited to one formed between carbon atoms, but also includes one containing a hetero atom such as a carbonyl group. Furthermore, in a broad sense, as a compound showing a π-conjugated structure, one in which unsaturated bonds are linked by a functional group composed of an atom having an unshared electron pair such as an amino group or an ether group can also be mentioned. The present invention is applicable to structures having all π conjugated structures which have been known so far, including these examples.

  As a typical example of the π conjugated structure, an aromatic ring structure can be mentioned. The aromatic ring structure in the present invention is a chemical structure defined as a general aromatic, in which, like benzene and naphthalene, unsaturated bonds contained in the structure are cyclically linked, It includes an aromatic ring structure which is π conjugated to form a planar structure. Also, the planarity of the compound can be determined by molecular orbital calculation.

  In the compound represented by the general formula (I) according to the present invention, it is expected that a compound having high coplanar π conjugation can be obtained by R and R ′ being a fused ring, but a solvent or From the viewpoint of compatibility with the cycloolefin resin, it is preferable to have a structure represented by the general formula (II). When the compound represented by the general formula (II) has sufficient compatibility with the solvent or the binder resin, it becomes easy to control the planarity of the compound.

（Ｒ１〜Ｒ３は、置換若しくは無置換のアリール基、又は複素環基である。Ｌ１〜Ｌ３は、単結合、又は炭素原子若しくは窒素原子を含む２価の連結基である。Ａ１〜Ａ６は、それぞれ独立に炭素原子、窒素原子、又は酸素原子である。）

(R1 to R3 each represents a substituted or unsubstituted aryl group or a heterocyclic group. L1 to L3 each represent a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. A1 to A6 each represent Each independently a carbon atom, a nitrogen atom or an oxygen atom)

  The six-membered aromatic ring represented by A1 to A6 is, for example, benzene ring, pyrrole ring, pyrazole ring, imidazole ring, 1,2,3-triazole ring, 1,2,4-triazole ring, triazine ring, tetrazole Ring, furan ring, oxazole ring, isoxazole ring, oxadiazole ring, isoxadiazole ring, thiophene ring, thiazol ring, isothiazole ring, thiadiazole ring, isothiadiazole ring and the like. Among these, a benzene ring, a pyrrole ring, a pyrazole ring, an imidazole ring and a triazine ring are preferable from the viewpoint of obtaining the planarity of the compound.

  In particular, the compound represented by the general formula (II) preferably has a structure represented by the general formula (III). The steric repulsion of the C—N bond of the triazine ring generates a suitable rotational barrier at a single bond connecting a triazine ring and R 1 to R 3, a carbon atom or a nitrogen atom, and the flatness of the compound is easily obtained. From the viewpoint of the above rotation barrier, at least one of L1 to 3 represented by General Formula (III) is preferably a single bond, and at least one of R1 to 3 is a substituted or unsubstituted benzene ring or pyrrole ring It is preferably a pyrazole ring, an imidazole ring or a triazine ring.

（Ｒ１〜Ｒ３は、置換若しくは無置換のアリール基又は複素環基である。Ｌ１〜Ｌ３は、単結合、又は炭素原子若しくは窒素原子を含む２価の連結基である。）

(R1 to R3 each represents a substituted or unsubstituted aryl group or heterocyclic group. L1 to L3 each represents a single bond or a divalent linking group containing a carbon atom or a nitrogen atom.)

  From the viewpoint of the rotation barrier, at least one of L1 to L3 represented by General Formula (III) is preferably a single bond, and at least one of R1 to R3 is preferably a benzene ring.

  In R of General Formula (1), R ‘, or R1 to R3 of General Formula (II) and General Formula (III), the same aryl group or heterocyclic group may be used, and they may be different from each other.

  The aryl group is preferably phenyl or naphthyl, particularly preferably phenyl. The aryl group may have a substituent. Examples of the substituent include a halogen atom, hydroxyl, cyano, nitro, carboxyl, alkyl group, alkenyl group, aryl group, alkoxy group, alkenyloxy group, aryloxy group, acyloxy group, alkoxycarbonyl group, alkenyloxycarbonyl group, Aryloxycarbonyl group, sulfamoyl, alkyl substituted sulfamoyl group, alkenyl substituted sulfamoyl group, aryl substituted sulfamoyl group, sulfonamide group, carbamoyl, alkyl substituted carbamoyl group, alkenyl substituted carbamoyl group, aryl substituted carbamoyl group, amide group, alkylthio group, alkenyl Thio group, arylthio group and acyl group are included. The alkyl group has the same definition as the alkyl group described above. The alkoxy group, the acyloxy group, the alkoxycarbonyl group, the alkyl substituted sulfamoyl group, the sulfonamide group, the alkyl substituted carbamoyl group, the amide group, the alkyl moiety of the alkylthio group and the acyl group are also the same as the alkyl group described above.

  The above alkenyl group has the same definition as the aforementioned alkenyl group. The alkenyloxy group, the acyloxy group, the alkenyloxycarbonyl group, the alkenyl substituted sulfamoyl group, the sulfonamide group, the alkenyl substituted carbamoyl group, the amide group, the alkenylthio group and the alkenyl moiety of the acyl group are also the same as the alkenyl group described above.

  Examples of the above aryl group include phenyl, α-naphthyl, β-naphthyl, 4-methoxyphenyl, 3,4-diethoxyphenyl, 4-octyloxyphenyl and 4-dodecyloxyphenyl. Examples of the aryloxy group, the acyloxy group, the aryloxycarbonyl group, the aryl substituted sulfamoyl group, the sulfonamide group, the aryl substituted carbamoyl group, the amide group, the arylthio group and the acyl group are the same as the examples of the aryl group.

  The heterocyclic group preferably has aromaticity. The heterocycle having aromaticity is generally an unsaturated heterocycle, preferably a heterocycle having the largest number of double bonds. The heterocycle is preferably a 5-, 6- or 7-membered ring, more preferably a 5- or 6-membered ring, and most preferably a 6-membered ring. The hetero atom of the heterocyclic ring is preferably N, S or O, and particularly preferably N. As a heterocyclic ring having aromaticity, a pyridine ring (as a heterocyclic group, 2-pyridyl or 4-pyridyl) is particularly preferable. The heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group are the same as the examples of the substituent of the aryl moiety described above.

  The heterocyclic group may be a heterocyclic group having a free valence at a nitrogen atom. The heterocyclic group having a free valence at a nitrogen atom is preferably a 5-, 6- or 7-membered ring, more preferably a 5- or 6-membered ring, and a 5-membered ring Is most preferred. The heterocyclic group may have a plurality of nitrogen atoms. In addition, the heterocyclic group may have a hetero atom (eg, O, S) other than nitrogen atom. The heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group are the same as the examples of the substituent of the aryl moiety described above.

  The aryl group or the heterocyclic group may have a substituent, and when there are a plurality of substituents, they may be the same or different and may form a ring. The following can be applied as examples of the substituent.

  A halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, for example, methyl group, ethyl group, n-propyl group, isopropyl group, tert- Butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably, substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, for example, cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl A bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms), that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example. Bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octan-3-yl), alky Group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, for example, a vinyl group, an aryl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having a carbon number of 3 to 30, That is, it is a monovalent group obtained by removing one hydrogen atom of a C3-C30 cycloalkene, for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group, bicycloalkenyl group (substituted or substituted). An unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond, for example, Bicyclo [2,2,1] hept-2-en-1-yl group, bicyclo [2,2,2] oct-2-en-4-yl group), alkynyl group Preferably, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as an ethynyl group or a propargyl group, an aryl group (preferably, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as a phenyl group, p A tolyl group, a naphthyl group), a heterocyclic group (preferably a 5- or 6-membered substituted or unsubstituted, aromatic or non-aromatic heterocyclic compound with one hydrogen atom removed), More preferably, it is a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, for example, 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group), cyano group, A hydroxy group, a nitro group, a carboxy group, an alkoxy group (preferably, a substituted or unsubstituted alkoxy group having a carbon number of 1 to 30, for example, a methoxy group, an ethoxy group, an isopropoxy group, tert-Butoxy group, n-octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably, substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, for example, phenoxy group, 2-methylphenoxy group , 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group), silyloxy group (preferably, a C3-C20 silyloxy group, for example, trimethylsilyloxy group, tert-butyldimethyl) Silyloxy group), heterocyclic oxy group (preferably, substituted or unsubstituted heterocyclic oxy group having 1 to 30 carbon atoms, 1-phenyltetrazole-5-oxy group, 2-tetrahydropyranyloxy group), acyloxy group (Preferably a formyloxy group, a substituted or unsubstituted group having 2 to 30 carbon atoms A carbonyl oxy group, a substituted or unsubstituted aryl carbonyloxy group having 6 to 30 carbon atoms, such as a formyloxy group, an acetyloxy group, a pivaloyloxy group, a stearoyloxy group, a benzoyloxy group, a p-methoxyphenyl carbonyloxy group) Carbamoyloxy group (preferably, a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholino carbonyloxy group, N, N-di-n-octylamino carbonyloxy group, N-n-octyl carbamoyloxy group), alkoxy carbonyloxy group (preferably, a substituted or unsubstituted alkoxy carbonyloxy group having 2 to 30 carbon atoms, for example, methoxy carbonyloxy group , Et And a substituted or unsubstituted aryloxycarbonyloxy group, for example, phenoxycarbonyl group; preferably a substituted or unsubstituted aryloxycarbonyloxy group, for example, phenoxycarbonyl group, tert-butoxycarbonyloxy group, n-octylcarbonyloxy group), aryloxycarbonyloxy group (preferably, 7 to 30 carbon atoms) Oxy group, p-methoxyphenoxy carbonyloxy group, p-n-hexadecyloxyphenoxy carbonyloxy group), amino group (preferably, amino group, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, carbon number 6 to 30 substituted or unsubstituted anilino groups, for example, amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably, formylamino group, Substituted or unsubstituted alkyl having 1 to 30 carbon atoms A carbonylamino group, a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino), aminocarbonylamino (preferably, Substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, such as carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonylamino Group (preferably a substituted or unsubstituted alkoxycarbonylamino group having a carbon number of 2 to 30, for example, methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbo Amino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably, substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, for example, phenoxycarbonylamino group, p-chlorophenoxy A carbonylamino group, m-n-octyloxyphenoxycarbonylamino group), a sulfamoylamino group (preferably, a substituted or unsubstituted sulfamoylamino group having a carbon number of 0 to 30, for example, a sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group), alkyl and arylsulfonylamino groups (preferably having 1 to 30 carbon atoms, substituted or unsubstituted alkylsulfonylamino, having 6 to 30 carbon atoms Substituted or unsubstituted aryl sulfone Amino group, for example, methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group), mercapto group, alkylthio group (preferably, A substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, such as methylthio, ethylthio and n-hexadecylthio), an arylthio group (preferably a substituted or unsubstituted arylthio group having 6 to 30 carbons, such as a phenylthio group , P-chlorophenylthio group, m-methoxyphenylthio group), heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having a carbon number of 2 to 30, for example, 2-benzothiazolylthio group, 1- Phenyltetrazol-5-ylthio group), sulfamoyl group (preferably It is preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, for example, N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N -Acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N'phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl and arylsulfinyl group (preferably, substituted or unsubstituted with 1 to 30 carbon atoms Alkylsulfinyl group, 6 to 30 substituted or unsubstituted arylsulfinyl group, for example, methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl group (preferably having carbon number) 1 to 30 substituted or unsubstituted alkylsulfonyl 6-30 substituted or unsubstituted arylsulfonyl groups, such as methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group), acyl group (preferably formyl group, 2 to 30 carbon atoms) A substituted or unsubstituted alkylcarbonyl group, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, such as an acetyl group or a pivaloylbenzoyl group), an aryloxycarbonyl group (preferably having a carbon number of 7 to 30) A substituted or unsubstituted aryloxycarbonyl group such as, for example, phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group), alkoxycarbonyl group (preferably having 2 carbon atoms) To 30 substituted or unsubstituted alkoxy Bonyl group, for example, methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, n-octadecyloxycarbonyl group), carbamoyl group (preferably, a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, for example, carbamoyl group Group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group, aryl and heterocyclic azo groups (preferably having 6 carbon atoms) -30 substituted or unsubstituted arylazo group, substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms, for example, phenylazo group, p-chlorophenylazo group, 5-ethylthio-1,3,4-thiadiazole- 2-ylazo group), imide group (preferably, N-succinimide group, N- Phthalimide group), Phosphino group (preferably, a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, for example, dimethyl phosphino group, diphenyl phosphino group, methyl phenoxy phosphino group), phosphinyl group (preferably, carbon And 2 to 30 substituted or unsubstituted phosphinyl groups, for example, phosphinyl groups, dioctyloxyphosphinyl groups, diethoxyphosphinyl groups), phosphinyl oxy groups (preferably, substitution of 2 to 30 carbon atoms or Unsubstituted phosphinyl oxy group (eg, diphenoxy phosphinyl oxy group, dioctyloxy phosphinyl oxy group), phosphinyl amino group (preferably, substituted or unsubstituted phosphinyl having 2 to 30 carbon atoms) Amino groups such as dimethoxyphosphinylamino group, dimethylaminophosphinylamino ), A silyl group (preferably, represents a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, e.g., trimethylsilyl group, tert- butyldimethylsilyl group, a phenyldimethylsilyl group).

  Examples of functional groups of the above-mentioned substituents include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group and a benzoylaminosulfonyl group.

  The boiling point of the compound represented by formula (III) is preferably 260 ° C. or more. The boiling point can be measured using a commercially available measuring device (for example, TG / DTA 100, manufactured by SII Nano Technology Inc.).

  In the present invention, the compounds having the structures represented by the general formulas (I to III) can be used alone or in combination of two or more.

  The molecular weight of the compound having a structure represented by the general formulas (I to III) is 100 when the dry film thickness of the cyclopolyolefin film is 15 to 50 μm from the viewpoint of the compatibility of the compound with the solvent or cycloolefin resin. It is preferably in the range of-3000, and more preferably in the range of 100-800. Within the range of 100 to 800, the occurrence of precipitation and bleed out of the compound itself can be suppressed, and orientation control of the planarity of the compound becomes easy. Furthermore, the volatility is low and the compound can be uniformly dispersed in the dope.

  The method of adding the compound having the structure represented by the general formula (I to III) described above is an alcohol such as methanol, ethanol, butanol or the like, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane or a mixed solvent thereof It may be dissolved and then added to the dope or may be added directly into the dope composition. As the organic solvent, one kind of organic solvent may be used alone, or two or more kinds of organic solvents may be mixed and used at an arbitrary ratio.

  The use amount of the compound having the structure represented by the general formulas (I to III) is not particularly limited as long as the effects of the present invention are exhibited, but from the viewpoints of prevention of bleed out and precipitation, adhesion, and visibility, cyclo The inside of the range of 2-20 mass% is preferable with respect to an olefin resin, and the range of 3-10 mass% is more preferable.

(Additive)
As described above, the optical film of the present invention may contain other optional components as long as the effects of the present invention are not impaired. In the present invention, the additive also has planarity in the same manner as the compound described above, from the viewpoint that the compound having a structure represented by the general formulas (I to III) is likely to suppress precipitation of the additive and the like. preferable.

  It is preferable to contain an ultraviolet absorber as an optional component from the viewpoint of improving the light resistance. The purpose of the ultraviolet absorber is to improve light resistance by absorbing ultraviolet rays of 400 nm or less, and in particular, the transmittance at a wavelength of 370 nm is preferably in the range of 2 to 30%, more preferably 4 It is preferably in the range of -20%, more preferably in the range of 5-10%.

  The UV absorbers preferably used in the present invention are benzotriazole based UV absorbers, benzophenone based UV absorbers and triazine based UV absorbers, and particularly preferably benzotriazole based UV absorbers and benzophenone based UV absorbers.

For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and sided Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone and the like, and tinuvin 109, tinuvin 171, tinuvin 234, tinuvin 326, tinuvin 327, tinuvin 32
And tinuvins such as tinuvin 928, all of which are commercial products manufactured by BASF Japan Ltd. and can be preferably used. Among these, halogen-free ones are preferable. The ultraviolet absorber may contain a plurality of types.

  The UV absorber may be added by dissolving the UV absorber in an alcohol such as methanol, ethanol, butanol or the like, an alcohol such as methylene chloride, methyl acetate, acetone, dioxolane or a mixed solvent thereof, and then adding it to the dope Alternatively, it may be added directly into the dope composition. Moreover, what does not melt | dissolve in the organic solvent like an inorganic powder should just be added to dope, using a dissolver or a sand mill in an organic solvent and acetyl cellulose, disperse | distributing.

  Moreover, as a ultraviolet absorber, a polymeric ultraviolet absorber can also be used preferably, and a polymer type ultraviolet absorber described in JP-A-6-148430 is particularly preferably used. Moreover, it is preferable that a ultraviolet absorber does not have a halogen group.

  The amount of UV absorber used is not uniform depending on the type of UV absorber, conditions of use, etc., but when the dry film thickness of the transparent resin film is 15 to 50 μm, 0.5 to 10 with respect to the transparent resin film The range of mass% is preferable, and the range of 0.6 to 3 mass% is more preferable.

(Method of forming transparent resin film)
Examples of the method for forming a transparent resin film used as the optical film of the present invention include known methods such as a melt extrusion method, a solution cast method (solution casting method), a calendar method, and a compression molding method.

  Examples of the solvent used in the solution casting method include chlorinated solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene and mixed solvents thereof; methanol, ethanol, isopropanol, n-butanol, Alcohol solvents such as 2-butanol; methyl cellosolve, ethyl cellosolve, butyl cellosolve, dimethylformamide, dimethyl sulfoxide, dioxane, cyclohexanone, tetrahydrofuran, acetone, methyl ethyl ketone (MEK), ethyl acetate, diethyl ether, and the like. These solvents may be used alone or in combination of two or more.

  In the case of forming a transparent resin film by a solution casting method, in a dope containing a compound having a structure represented by the general formulas (I to III) and a solvent, the difference in the boiling point of the mixed solvent in the dope and the compound The compound may be localized near the surface of the transparent resin film by utilizing the solubility of the compound or the polarity of the functional group. By controlling the planarity of the localized compound, the appropriate smoothness and uniform surface of the transparent resin film surface are effectively formed, and the adhesion between the transparent resin film and the hard coat layer is effectively reduced. Is expected to be

  Hereinafter, a method of localizing the compound having a structure represented by the general formulas (I to III) in the solution casting method near the surface of the transparent resin film will be described in detail.

  In one embodiment in the case of utilizing the difference in the boiling point of the mixed solvent in the dope and the solubility with the compound, at least a cyclopolyolefin resin and a compound having a structure represented by the general formulas (I to III) are dissolved Preparing the dope, casting the dope on a belt-like or drum-like metal support, drying the cast dope as a web, peeling it from the metal support, stretching or holding the width It is characterized by having a process, a process of further drying, and a process of winding up a finished film.

  When a dope containing a compound having a structure represented by the general formula (I) is cast on a support, and dried on the support, the dope is volatilized from the side opposite to the support. Distribution occurs in the thickness direction. If the mixed solvent is volatilized from a low boiling point, a distribution of low boiling point and high boiling point occurs in the thickness direction. At this time, the solubility of the compound having the structure represented by the general formulas (I to III) causes localization of the compound in the thickness direction in the film after drying. When the compound having the structure represented by the general formulas (I to III) has a higher solubility in a low boiling point solvent than a high boiling point solvent, the compound is in the direction of volatilization (opposite to the support) Is localized near the surface because On the other hand, when the solubility is low, the compound is not localized due to the volatilization, so the localization is difficult.

  When a nonpolar solvent such as dichloromethane and a polar solvent such as ethanol are used as a mixed solvent and the compound having a structure represented by the general formula (I) has a highly polar functional group, it dissolves in the nonpolar solvent It is difficult to dissolve in polar solvents. In addition, since dichloromethane and ethanol have different boiling points, they evaporate from the low boiling point dichloromethane on the support and ethanol becomes rich on the support surface.

  Moreover, when utilizing the polarity of the functional group of the compound which has a structure represented by general formula (I-III), the compound which has a structure represented by general formula (I-III) is a highly polar functional group, for example In the case where it has an H.sub.2 O.sub.2, since it is insoluble in dichloromethane and soluble in ethanol, it is biased and localized on the support surface (ethanol-rich side).

  In the solution casting method, it is preferable that the concentration of the cyclopolyolefin resin in the dope is high because the drying load after casting on the metal support can be reduced, but if the concentration of the cyclopolyolefin resin is too high, The load on the As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%. The metal support in the casting (cast) step preferably has a mirror-finished surface, and as the metal support, a stainless steel belt or a drum having a surface plated with a casting is preferably used.

  The width of the cast can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to a temperature not higher than -50 [deg.] C. and boiling. A higher temperature is preferable because the drying speed of the web can be increased, but if it is too high, the web may foam or the flatness may be deteriorated.

  As preferable support body temperature, it determines suitably at 0-100 degreeC, and 5-30 degreeC is further more preferable. Alternatively, it is also a preferable method to gelate the web by cooling and peel it from the drum in a state of containing a large amount of residual solvent. The method of controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air and a method of contacting warm water with the back side of the metal support. Use of hot water is preferable because heat transfer is efficiently performed, so the time until the temperature of the metal support becomes constant is short.

  When using warm air, in consideration of the temperature drop of the web due to the latent heat of vaporization of the solvent, there are cases where wind of a temperature higher than the target temperature is used while preventing foaming while using warm air higher than the boiling point of the solvent .

  In particular, it is preferable to conduct drying efficiently by changing the temperature of the support and the temperature of the drying air from casting to peeling.

  The amount of residual solvent at the time of peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass, in order for the transparent resin film to exhibit good planarity. Particularly preferably, it is 20 to 30% by mass or 70 to 120% by mass.

  The amount of residual solvent is defined by the following equation.

Residual solvent amount (mass%) = {(M−N) / N} × 100
Here, M is the mass of the sample collected at any time during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  In the step of drying the transparent resin film, the web is peeled off from the metal support and dried, and the amount of residual solvent is preferably 1% by mass or less, more preferably 0.1% by mass or less. Particularly preferably, it is 0 to 0.01% by mass or less.

  In the film drying process, in general, a method of drying while conveying the web by a roller drying method (a method of passing the web alternately through a large number of rollers arranged above and below) or a tenter method is adopted.

(Stretching process)
The transparent resin film according to the present invention has a stretching step in order to control the orientation direction of the compound having a structure represented by the general formulas (I to III).

  The compound enters the free volume between the resin or bonds with the resin, whereby the resin is stretched at the same time as stretching, and at the same time the compound is aligned in the stretching direction with the compound surface oriented, stretching magnification and stretching temperature stressing on the resin The orientation of the compound can be controlled by adjusting the direction or the resin hardness.

  There is no limitation in particular in the method to extend | stretch. For example, circumferential speed difference is given to a plurality of rollers, and the method of stretching in the longitudinal direction using the circumferential speed difference of the rollers between them, both ends of the web are fixed by clips or pins, and the distance between clips or pins is extended in the traveling direction Similarly, a method of stretching in the crosswise direction and a method of stretching in the crosswise direction, or a method of simultaneously stretching in the longitudinal and transverse directions and stretching in the longitudinal and transverse directions may be mentioned. Of course, these methods may be used in combination. That is, the film may be stretched in the transverse direction, in the longitudinal direction, or in both directions with respect to the film forming direction, and in the case of stretching in both directions, sequential stretching is possible even if simultaneous stretching. It is good. In the case of the so-called tenter method, it is preferable to drive the clip portion by the linear drive method, because smooth stretching can be performed and the risk of breakage or the like can be reduced.

  In the present invention, in particular, stretching is performed in the transport direction by utilizing the peripheral speed difference of the film transport roller, or both ends of the web are clipped in the direction orthogonal to the transport direction (also referred to as width direction or TD direction) It is preferable to use a tenter method for holding at the same time, and it is also preferable to use a tenter that can independently control the holding length of the web (the distance from the start of holding to the end of holding) by the left and right holding means.

  In the present invention, the both ends of the transparent resin film were stretched at an angle within the range of -90 to 0 ° with respect to the transport direction and at a stretching ratio within the range of 50 to 100%. The in-plane retardation value Ro (550) is preferably 90 to 170 nm, more preferably 120 to 160 nm, and still more preferably 130 to 150 nm. Thereby, it is presumed that the plane of the compound represented by the general formulas (I to III) is oriented so as to be perpendicular to the thickness direction of the transparent resin film.

  In the present invention, a particularly preferred stretching method is stretching in the TD direction 1.03 to 1.30 times, preferably 1.05 to 1.20 times in the tenter, and then 1.50 to 2.5 times in the diagonal direction Stretching is preferred. By stretching in the width direction before stretching in the oblique direction, flatness and thickness deviation of the film are improved.

  The temperature at which the film is obliquely stretched is preferably in the temperature range of Tg-30 ° C. to Tg + 60 ° C., more preferably Tg-10 ° C. to Tg + 50 ° C., where Tg is the glass transition temperature of the thermoplastic resin. . The stretching ratio is usually 1.01 to 30 times, preferably 1.01 to 10 times, more preferably 1.01 to 5 times.

  The orientation angle when the film is obliquely stretched is 20 to 70 °, preferably 30 to 60 °, and more preferably 40 to 50 ° with respect to the width direction. By making such an orientation angle, the in-plane retardation (Re) of the film can be made suitable.

The thickness of the finished (after drying) transparent resin film of the present invention varies depending on the purpose of use, but is usually in the range of 5 to 500 μm, preferably in the range of 10 to 150 μm, and for liquid crystal display devices at 20 to 110 μm. It is preferable that the thickness is 40 μm or less in consideration of recent thinning.
In order to thin the transparent resin film to 40 μm or less, generally, it is necessary to increase the content of the additive to maintain the performance of the transparent resin film, and the bleeding out of the additive becomes a problem. The compound having a structure represented by the general formulas (I to III) according to the invention has an effect of suppressing the precipitation of the additive contained in the transparent resin film, and thus the adhesion improvement between the thin film transparent resin film and the hard coat layer In the above, the configuration of the present invention can be used effectively.

  The preparation of the film thickness is such as to obtain the desired thickness and thickness distribution according to the present invention, the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, etc. Adjust the The width of the transparent resin film obtained as described above is preferably in the range of 0.5 to 4 m, more preferably in the range of 0.6 to 3 m, and still more preferably 0.8 to 2.5 m. The length is preferably in the range of 100 to 10000 m per roll, more preferably in the range of 500 to 9000 m, and still more preferably in the range of 1000 to 8000 m.

  The transparent resin film according to the present invention can achieve desired optical properties by appropriately adjusting the process conditions such as the polymer structure used, the type and amount of additives, the draw ratio, and the residual volatile content at peeling. . For example, it is also possible to widely control the retardation value Rt in the thickness direction to 180 to 300 nm by adjusting the amount of residual solvent at the time of peeling within 40 to 85% by mass. In general, Rt decreases as the amount of residual solvent at the time of peeling increases, and Rt increases as the amount of residual solvent at the time of peeling decreases. For example, by shortening the drying time on a metal endless support and increasing the amount of residual solvent at the time of peeling, it is possible to relax the surface orientation and lower Rt, and adjust the process conditions. It is possible to develop different retardations depending on different applications.

In the present specification, Ro and Rt respectively represent the in-plane retardation value and the retardation value in the thickness direction at the light wavelength λ. Ro is measured by causing light of wavelength λ nm to be incident in the film normal direction in KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.). Rt is measured by making light of wavelength λ nm incident from a direction inclined by + 40 ° with respect to the film normal direction with Ro, the in-plane slow axis (as judged by KOBRA 21ADH) as the inclination axis (rotational axis) Retardation value, and a total of three retardation values measured by causing light of wavelength λ nm to be incident from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the inclination axis (rotation axis) KOBRA 21ADH is calculated based on the retardation value measured in one direction. Here, it is possible to use the values of the catalog of various optical films and the polymer handbook (JOHN WILEY & SONS, INC) as the assumed value of the average refractive index. If the value of the average refractive index is not known, it can be measured by an Abbe refractometer. KOBRA 21ADH calculates n _x , n _y and n _z and calculates a retardation value based on the following formulas (i) and (ii) by inputting the hypothetical value of the average refractive index and the film thickness.

Formula _{(i): Ro = (n} x -n y) × d (nm)
Formula (ii): Rt = {(n _x + n _y ) / 2−nz} × d (nm)
(Wherein, Ro represents the in-plane retardation value in the film, Rt represents the retardation value in the thickness direction in the film, and d represents the thickness (nm) of the optical film. N _x Represents the maximum refractive index in the plane of the film, and is also referred to as the refractive index in the slow axis direction, and n _y represents the refractive index in the direction perpendicular to the slow axis in the film plane, and nz is the thickness Represents the refractive index of the film in the direction)

  The transparent resin film according to the present invention is preferably highly transparent from the viewpoint of contrast improvement and luminance improvement. The total light transmittance measured after humidity control in an environment of 23 ° C. and 55% RH is 80% or more, preferably 85% or more, more preferably 90% or more, and particularly preferably 95% or more. The total light transmittance can be measured in accordance with JIS 7573 "Plastics-Determination of total light transmittance and total light reflectance".

  The transparent resin film according to the present invention preferably has an equilibrium water content of 3% or less at 25 ° C. and a relative humidity of 60% from the viewpoint of phase difference fluctuation and bending, and more preferably 1% or less. By setting the equilibrium water content to 3% or less, it is easy to cope with humidity changes, and optical properties and dimensions are less likely to change, which is preferable.

  The equilibrium moisture content is as follows: the sample film is left in a room conditioned at 23 ° C. and relative humidity 20% for 4 hours or more, and then left in a room conditioned at 23 ° C. 80% RH for 24 hours. Moisture is dried and vaporized at a temperature of 150 ° C. using a meter (for example, CA-20 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and then quantified by the Karl Fischer method.

<Hard coat layer>
The optical film of the present invention is characterized by containing a hard coat layer. By having the hard coat layer, the impact resistance, the ease of handling, etc. of the optical film can be improved.

  The material for forming the hard coat layer is not particularly limited as long as it exhibits a hardness of “HB” or more in a pencil hardness test defined in JIS K5700, but contains a cured product of an actinic radiation curable compound. It is preferable to use, and as the actinic radiation curable compound, a component containing a monomer having an ethylenically unsaturated double bond is preferably used. Examples of the actinic ray curable compound include an ultraviolet ray curable compound and an electron beam curable compound, but a compound which is cured by ultraviolet ray irradiation is preferable from the viewpoint of excellent mechanical film strength (abrasion resistance, pencil hardness).

  For example, organic hard coat materials such as organic silicones, melamines, epoxys, acrylates and polyfunctional (meth) acrylic compounds; inorganic hard coats such as silicon dioxide; and the like can be mentioned. Among them, from the viewpoint of good adhesion and excellent productivity, it is preferable to use a hard coat-forming material of (meth) acrylate type or polyfunctional (meth) acrylic compound. Here, (meth) acrylic indicates acrylic and methacrylic.

  (Meth) acrylates are those having one polymerizable unsaturated group in the molecule, those having two or three or more, and (meth) acrylate oligomers having three or more polymerizable unsaturated groups in the molecule. Can be mentioned. The (meth) acrylates may be used alone or in combination of two or more.

  In addition, various additives can be added to the hard coat layer according to the present invention as needed, as long as the effects of the present invention are not impaired. For example, an antioxidant, an ultraviolet light stabilizer, an ultraviolet light absorber, a surfactant, a leveling agent, an antistatic agent, etc. can be used. The hard coat layer of the present invention has particles with an average particle size of 0.2 to 10 μm. The antiglare property may be imparted by containing the above, or high refractive index fine particles may be dispersedly contained to give a refractive index.

  The leveling agent is particularly effective in reducing surface unevenness when applying a hard coat layer. For example, a dimethylpolysiloxane-polyoxyalkylene copolymer is suitable as the silicone leveling agent as the renelling agent.

  As particles having an average particle size of 0.2 to 10 μm, inorganic particles are preferable. Examples of the inorganic particles include silica, zinc oxide, ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), oxide At least one selected from the group consisting of tin, indium oxide, tungsten oxide, composite tungsten oxide and antimony oxide can be mentioned. Among them, silica fine particles are preferable because the improvement effect of the surface hardness can be made particularly high and the strength can be made particularly high. In addition, it is preferable to use ITO, ATO, tungsten oxide or composite tungsten oxide from the viewpoint of adding ultraviolet absorbing performance to the hard coat layer and suppressing deterioration of the hard coat layer with time.

  As the ultraviolet light stabilizer, for example, a hindered amine ultraviolet light stabilizer having high stability to ultraviolet light is suitably used. When the hard coat layer contains an ultraviolet light stabilizer, radicals generated by ultraviolet light, active oxygen and the like can be inactivated, and ultraviolet light stability, weather resistance, and the like can be improved.

  Examples of the UV absorber include salicylic acid UV absorber, benzophenone UV absorber, benzotriazole UV absorber, cyanoacrylate UV absorber, triazine UV absorber, benzooxazinone UV absorber and the like. It is possible to use one or more selected from these groups. Among them, triazine-based ultraviolet absorbers and benzoxazinone-based ultraviolet absorbers are preferable from the viewpoint of dispersibility. Moreover, as said ultraviolet absorber, the polymer which has an ultraviolet absorption group in a molecular chain is also used suitably. By using a polymer having an ultraviolet absorbing group in such a molecular chain, it is possible to prevent the deterioration of the ultraviolet absorbing function due to the bleeding out of the ultraviolet absorber and the like. Examples of the UV absorbing group include benzotriazole group, benzophenone group, cyanoacrylate group, triazine group, salicylate group and benzylidene malonate group. Among them, benzotriazole group, benzophenone group and triazine group are particularly preferable.

The method of forming the hard coat layer is not particularly limited, and the coating solution of the hard coat forming material may be dip, spray, slide coat, bar coat, roll coater, die coater, gravure coater, screen printing After applying an acrylic hard coat material after applying an optical film containing an alicyclic structure-containing polymer by a known method such as a method and removing it by drying under an atmosphere of air or nitrogen, etc. It is carried out by cross-linking and curing with an electron beam or the like, or by applying a silicone-based, melamine-based or epoxy-based hard coating material and thermally curing it. Since the film thickness unevenness of the coating film tends to occur at the time of drying, it is preferable to control the intake film and the exhaust gas so as not to damage the coating film appearance so that the entire coating film becomes uniform. When using a material that cures with ultraviolet light, the irradiation time for curing the hardcoat-forming material after application is generally in the range of 0.01 seconds to 10 seconds, and the irradiation dose of the energy radiation source is ultraviolet light with a wavelength of 365 nm. of accumulative exposure in a range of usually 40 mJ / cm ² of 1000 mJ / cm ^2. The irradiation of ultraviolet light may be performed, for example, in an inert gas such as nitrogen and argon, or may be performed in the air.

  The dry layer thickness of the hard coat layer is in the range of an average layer thickness of 0.01 to 20 μm, preferably in the range of 0.5 to 10 μm. More preferably, it is in the range of 0.5 to 5 μm.

«Application of optical film»
It is preferable that the optical film of this invention is a functional film used for various display apparatuses, such as a liquid crystal display, a plasma display, and an organic electroluminescent display, or a touch panel. Specifically, the optical film of the present invention is a polarizing plate protective film for liquid crystal display devices, retardation film, antireflection film, brightness enhancement film, hard coat film, antiglare film, antistatic film, viewing angle enlargement, etc. The optical compensation film of Typically, the optical film of the present invention is a polarizing plate protective film, a retardation film, an optical compensation film. The optical film of the present invention can serve both as a retardation film and a polarizing plate protective film.

  Hereinafter, the present invention will be described in more detail by way of examples. The materials used are as follows.

(Compound represented by general formula (I))
Compound 1: Tinuvin 479 (manufactured by BASF Japan Ltd.)
Compound 2: Tinuvin 460 (manufactured by BASF Japan Ltd.)
Compound 3: (Chem. 1) described in JP-A-2005-25120
Compound 4: Tinuvin 1577 (manufactured by BASF Japan Ltd.)

(Comparison compound)
Compound 5: triphenyl phosphate

Also, the SP values of the compounds are shown in Table 1 below.

The SP value in the present invention can be determined by calculation using the parameters of Fedors. The unit of the SP value is "(cm ³ / cal) ^1/2 ", which is the square root of the cohesive energy density ΔE divided by the molar volume V. The parameters of the Fedors are described in the reference: Basic science of coating by Yuji Harada 槇 bookstore (1977) p 54-57.

«Preparation of optical film 1»
Preparation of Hard Coat Layer Coating Solution 1
Hard coat layer coating solution 1 of the following composition was prepared. After mixing the ultraviolet curable resin, the surfactant and propylene glycol monomethyl ether, the mixture was stirred for 30 minutes to prepare Hard coat layer Coating solution 1.

Ultraviolet curable resin (Opster Z7527, manufactured by JSR Corporation) 100 parts by mass Surfactant (Surflon S-651, manufactured by AGC Seimicchemical) 0.1 part by mass, methyl ethyl ketone 30 parts by mass

Preparation of Hard Coat Layer Coating Solution 2
Hard coat layer coating solution 2 of the following composition was prepared in the same manner as hard coat layer coating solution 1.

Ultraviolet curable resin (Opstar Z7527 manufactured by JSR Corporation) 100 parts by mass Surfactant (Surflon S-651 manufactured by AGC Seimicical Co., Ltd.) 0.1 parts by mass 0.1 part by mass methyl ethyl ketone 20 parts by mass

Preparation of Hard Coat Layer Coating Solution 3
Hard coat layer coating solution 3 of the following composition was prepared in the same manner as hard coat layer coating solution 1.

UV curable resin (Opster Z7527, manufactured by JSR Corporation) 100 parts by weight Surfactant (Surflon S-651, manufactured by AGC Seimicical Co., Ltd. 0.1 part by weight Methyl ethyl ketone 30 parts by weight PMMA particles (Sekisui Chemical Co., Ltd. number average particle manufactured by 2.0 μm) 3 parts by mass

<Preparation of Fine Particle Dispersion>
11.3 parts by mass of fine particles (Aerosil R972V, manufactured by Nippon Aerosil Co., Ltd.) and 84 parts by mass of ethanol were mixed by stirring with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

  5 parts by weight of the fine particle dispersion was slowly added to well-stirred methylene chloride (100 parts by weight) in the dissolution tank. Furthermore, dispersion was performed with an attritor so that the particle size of the secondary particles would be a predetermined size. The resultant was filtered with FINEMET NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.

<Preparation of main dope>
The main dope of the following composition was prepared. First, dichloromethane and ethanol were added to the pressure dissolution tank. The cycloolefin resin, the compound 1, the ultraviolet light absorber, and the fine particle additive solution were charged into a pressure dissolution tank containing a mixed solution of dichloromethane and ethanol while stirring. Heat it up and dissolve completely while stirring. This is referred to as Azumi Filter Paper No. 4 manufactured by Azumi Filter Paper Co., Ltd. Filtered using 244 to prepare the main dope.

Cycloolefin resin (ARTON G7810, manufactured by JSR Corporation) 100 parts by mass Dichloromethane (SP value: 20) 200 parts by mass Ethanol (SP value: 26) 10 parts by mass Compound 1 5 parts by mass Ultraviolet absorber (Tinuvin 928, BASF Japan 4 parts by mass Fine particle added liquid 3 parts by mass

  The above components were charged into a closed vessel and dissolved with stirring to prepare a main dope. Next, the dope was uniformly cast on a stainless steel belt support at a temperature of 31 ° C. and a width of 1800 mm using an endless belt casting apparatus. The temperature of the stainless steel belt was controlled at 28 ° C.

The solvent was evaporated on a stainless steel belt support until the amount of residual solvent in the cast film was 30%. Then, it peeled from the stainless steel belt support with a peeling tension of 128 N / m. The peeled film was stretched 1.15 times in the width direction under the condition of 160 ° C. The residual solvent at the start of stretching was 5% by mass. Then, the drying was finished while being conveyed by a large number of rollers, and the end portion sandwiched by the tenter clips was slit with a laser cutter, and then wound up to obtain a raw film.
The obtained raw film was further diagonally stretched so that the slow axis and the longitudinal direction become 45 ° at a draw ratio of 1.75 times under the temperature condition of 200 ° C., to obtain a transparent resin film 1.

  The hard coat layer coating solution 1 was applied to one surface of the transparent resin film obtained above using microgravure so as to have a dry film thickness of 5 μm, and dried.

Then, using a high-pressure mercury lamp, the coating film was cured by ultraviolet irradiation with a light amount of 270 mJ / cm ² in the atmosphere to obtain an optical film 1 having a hard coat layer formed on a transparent resin film 1.

«Production of Optical Film 2 to 24»
As a structure shown in Table 2, it carried out similarly to the optical film 1, and produced.

«Evaluation of optical film»
The following evaluation was performed with respect to the produced optical films 1-24. The evaluation results are shown in Table 3.

<Surface hardness>
The optical films 1 to 24 were scratched repeatedly five times with a pencil of each hardness using a 500 g weight according to the pencil hardness evaluation method defined by JIS-K5400 using a pencil for testing defined by JIS-S6006. The hardness until one scratch was measured was measured. The higher the number, the higher the hardness.

<Adhesiveness>
After conditioning the optical films 1 to 24 in an atmosphere of 23 ° C. and 55% RH for 12 hours, a method according to JIS K 5400, 11 cuts longitudinally and laterally at intervals of 1 mm on the hard coat layer surface of the optical films 1 to 24 The pieces were inserted, 1 mm square, 100 grids were made, cellophane tape was attached, and they were quickly peeled off at a 90 degree angle. The cellophane tape was subjected to the peeling operation of the tape six times while being exchanged each time it was peeled once, and the area of the grids remaining without peeling was evaluated according to the following criteria.

:: not peeled at all ○: area ratio of peeled squares was less than 5% Δ: area ratio of peeled squares was less than 10% x: area of peeled squares The percentage was over 10%

<Evaluation of point-like defects>
The optical films 1 to 24 were incorporated into a liquid crystal display device, and the point-like or point-like locally concentrated state when black was displayed was observed visually for light and dark which appeared as a plane and evaluated according to the following criteria. In addition, if it is more than (triangle | delta), it can use for practical use.

:: There is no light leakage, and the entire dark field is uniform ○: Partial slight contrast is observed. Δ: Overall slight contrast is observed, but this is a practically acceptable level.
X: Light and dark are observed on the whole

<< Preparation of Polarizing Plates 1 to 24 >>
The polarizing plate can be produced by a general method. After alkali saponification treatment of the produced optical films 1-24,
Using a 5% aqueous solution of completely saponified polyvinyl alcohol as an adhesive, the both surfaces of the polarizer were bonded. At that time, polarizing plates 1 to 24 were produced by laminating such that the transmission axis of the polarizer and the slow axis of the λ / 4 film were 45 °, and the slow axes of the λ / 4 film coincide with each other.

<< Production of Liquid Crystal Displays 1 to 24 >>
The polarizing plate on the viewer side of the commercially available IPS type liquid crystal display device is peeled off, and the prepared polarizing plates 1 to 24 are bonded to the glass surface of the liquid crystal cell (IPS type) to obtain a liquid crystal display device. Made. At that time, the polarizing plate is made so that the absorption axis of the polarizing plate is oriented in the same direction as that of the polarizing plate previously bonded so that the produced optical films 1 to 24 are on the display surface side. I cut it out.

<< Evaluation of Liquid Crystal Display >>
The following evaluation was performed with respect to the produced liquid crystal display devices 1-24. The evaluation results are shown in Table 3.

<Evaluation of visibility when wearing sunglasses>
The image was displayed on the liquid crystal display device, visually observed by a subject wearing sunglasses, and evaluated according to the following criteria.
:: There is no difference in the appearance of the image even if you change the observation angle
○: The screen looks slightly darker depending on the angle to be observed Δ: The screen looks slightly darker or distorted depending on the angle to be observed ×: The screen clearly looks darker or distorted depending on the angle to be observed

  From the above results, it was found that the optical films 1 to 16 and 24 satisfying the requirements of the present invention have excellent adhesion between the transparent resin film and the hard coat layer.

  On the other hand, when the optical films 17 and 23 do not contain the compound having the structure represented by the general formula (I) according to the present invention, or the optical film 18 does not satisfy the requirements of the general formula (I) It was found that the adhesion was inferior when it contained.

  When the content of the compound having the structure represented by the general formula (I) does not satisfy the requirements of the present invention as in the optical films 19 and 20, it is represented by the added ultraviolet absorber or the general formula (I) It was found that the effect of the precipitation of the compound having the following structure or the compound having the structure represented by the general formula (I) can not be obtained and the adhesion and the surface hardness are inferior.

  Furthermore, when the retardation value of a transparent resin film does not satisfy | fill the requirements of this invention like the optical films 21-23, it turned out that it is inferior to adhesiveness and surface hardness. It is presumed that this is because the orientation of the compound represented by the general formula (I) is insufficient.

  From the above results, it was found that the polarizing plate and display device satisfying the requirements of the present invention have excellent visibility.

1 Optical Film 2 Transparent Resin Film 3 Hard Coat Layer 4 Examples of Compounds Having a Structure Represented by General Formula (I)

Claims (10)

In an optical film provided with a hard coat layer on at least one surface of a transparent resin film containing a cycloolefin resin as a main component,
The compound having a structure represented by the general formula ( II ) is contained in the range of 2 to 20% by mass with respect to the cycloolefin resin,
The in-plane retardation value Ro (550) of the transparent resin film measured with light of wavelength 550 nm is in the range of 120 to 160 nm,
Stretched so that the slow axis and the longitudinal direction of the transparent resin film are 45 °, and
An optical film characterized in that the planarity of the compound is controlled to be vertically oriented with respect to the thickness direction of the transparent resin film.

(R1 to R3 each represents a substituted or unsubstituted aryl group or a heterocyclic group;
L1 to L3 each represent a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. ;
A1 to A6 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. ) The optical film according to claim 1 , wherein the six-membered ring aromatic group represented by A1 to A6 in the general formula (II) is a triazine ring group. The optical film according to claim 1 or 2 , wherein in the general formula (II), at least one of L1 to L3 is a single bond. In the general formula (II), to claims 1 to 3, characterized in that it is substituted by at least one is a substituted or unsubstituted aromatic hydrocarbon ring group or an aromatic heterocyclic group R1~R3 The optical film according to any one of the above. The thickness of the said transparent resin film is 40 micrometers or less, The optical film as described in any one of Claim 1- Claim 4 characterized by the above-mentioned. It is a manufacturing method of the optical film which manufactures the optical film as described in any one of Claim 1- Claim 5, Comprising:
The method of manufacturing an optical optical film you characterized by forming said transparent resin film with a solution drooling method.   The optical film according to claim 6, wherein the transparent resin film is stretched in a width direction orthogonal to the transport direction, and then stretched in an oblique direction of 45 ° with respect to the width direction. Method.   The stretching in the width direction is in the range of 1.03 to 1.30 times, and
  The method for producing an optical film according to claim 7, wherein the stretching in the oblique direction is in a range of 1.50 to 2.5 times. A polarizing plate comprising the optical film according to any one of claims 1 to 5 .   A display device comprising the polarizing plate according to claim 9.

Images