JP2016074776A - Optical film, optical film manufacturing method, polarizing plate, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film having excellent adhesiveness between a transparent resin film and a hard coat layer, an optical film manufacturing method, a polarizing plate, and a display device.SOLUTION: In an optical film of the present invention where a hard coat layer is formed on at least one surface of a transparent resin film containing a cycloolefin resin as a main component, a compound represented by general formula (I) is contained in a range of 2-20 mass% based on the cycloolefin resin, and a retardation value Ro (550) in a plane of the transparent resin film measured with light having a wavelength of 550 nm is in a range of 90-170 nm.SELECTED DRAWING: Figure 1

Description

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

  Transparent resin films containing cellulose ester, polycarbonate, cycloolefin and the like are used for optical films, mainly for optical compensation films for liquid crystal display devices. Among them, cycloolefin resins are widely used because of their excellent transparency and moldability.

  In recent years, the performance of display devices has increased, and along with this, there has been an increasing demand for improvement in optical characteristics and scratch resistance in optical films constituting display devices. In order to improve the performance of an optical film, it is generally performed to provide a hard coat layer on the surface of a transparent resin film.

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

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 size of 1.0 μm. Containing irregularities with 10-point average roughness (Rz) of 0.1 μm or more and 1.0 μm or less on the surface of the hard coat layer by containing organic particles of 4.0 μm or less and inorganic fine particles having an average particle diameter of 50 nm or less. A method is disclosed in which the adhesiveness with the cycloolefin film is improved by forming a portion and setting the static friction coefficient and the dynamic friction coefficient to 0.9 or less between the hard coat layer surface and the cycloolefin film.
However, the configuration described in Patent Document 1 has a problem in that the adhesion is insufficient, and the requirements for maintaining optical visibility and improving scratch resistance cannot be satisfied.

JP 2013-186236 A

  The present invention has been made in view of the above-described problems and situations, and the problem to be solved is an optical film having excellent adhesion between the transparent resin film and the hard coat layer, a method for producing the optical film, a polarizing plate, and a display. Is to provide a device.

  As a result of intensive studies to solve the above problems, the inventors of the present invention contain a compound represented by the following general formula (I) in a cycloolefin resin in an amount of 2 to 20% by mass and control the orientation of the compound to be transparent. The present inventors have found that the above problems can be solved by forming a resin film, and have reached the present invention.

  In the present invention, the compound is contained in a transparent resin film, and the transparent resin film is stretched to control the flatness of the compound so that it is oriented perpendicularly to the thickness direction of the transparent resin film. Applicability of the coating solution for forming a hard coat layer on the transparent resin film plane in order to suppress the precipitation of the compound contained in the resin film and enable the formation of an appropriate smoothness and uniform surface on the transparent resin film surface. It is presumed 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.

（Ｒ及びＲ‘は、置換又は無置換の６員環芳香族基である。；
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。）
２．前記一般式（Ｉ）で表される構造を有する化合物が、一般式（ＩＩ）で表される構造を有する化合物であることを特徴とする第１項に記載の光学フィルム。

（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。）
３．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さらに２項に記載の光学フィルム。
４．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２項又は第３項に記載の光学フィルム。
５．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２項〜第４項のいずれか一項に記載の光学フィルム。
６．前記透明樹脂フィルムが、紫外線吸収剤を含有していることを特徴とする第１項〜第５項のいずれか一項に記載の光学フィルム。
７．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〜第６項のいずれか一項に記載の光学フィルム。
８．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第１項〜第７項のいずれか一項の光学フィルムの製造方法。
９．前記透明樹脂フィルムの両端が搬送方向に対して−９０〜０°の範囲内の角度で、かつ５０〜１００％の範囲内の延伸率で、延伸することを特徴とする第８項に記載の光学フィルムの製造方法。
１０．第１項〜第７項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。
１１．第１０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,
Containing a compound having a structure represented by the general formula (I) with respect to the cycloolefin resin within a range of 2 to 20% by mass;
An in-plane retardation value Ro (550) measured with light having a wavelength of 550 nm of the transparent resin film is in the range of 90 to 170 nm.

(R and R ′ are substituted or unsubstituted 6-membered aromatic groups;
L is a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. ;
n is an integer of 0-2. )
2. 2. The optical film according to item 1, wherein the compound having the structure represented by the general formula (I) is a compound having a structure represented by the general formula (II).

(R1 to R3 are a substituted or unsubstituted aryl group or a heterocyclic group;
L1 to L3 are a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. ;
A1 to A6 are each independently a carbon atom, a nitrogen atom, or an oxygen atom. )
3. The optical film according to Item 2, wherein in the general formula (II), the 6-membered aromatic group represented by A1 to A6 is a triazine ring group.
4). In the general formula (II), at least one of L1 to L3 is a single bond, The optical film as described in the second or third item.
5. In the general formula (II), at least one of R1 to R3 is substituted with a substituted or unsubstituted aromatic hydrocarbon ring group or aromatic heterocyclic group. The optical film as described in any one.
6). The said transparent resin film contains the ultraviolet absorber, The optical film as described in any one of Claims 1-5 characterized by the above-mentioned.
7). The thickness of the said transparent resin film is 40 micrometers or less, The optical film as described in any one of Claims 1-6 characterized by the above-mentioned.
8). 8. The method for producing an optical film according to any one of items 1 to 7, wherein the transparent resin film is formed by a solution fluent method.
9. The both ends of the transparent resin film are stretched at an angle in the range of -90 to 0 ° with respect to the transport direction and at a stretch rate in the range of 50 to 100%. Manufacturing method of optical film.
10. A polarizing plate comprising the optical film according to any one of Items 1 to 7.
11 A display device comprising the polarizing plate described in item 10.

  By the said means of this invention, the optical film which has the outstanding adhesiveness between a transparent resin film and a hard-coat layer, the manufacturing method of an optical film, a polarizing plate, and a display apparatus can be provided.

Schematic diagram of optical film

  Hereinafter, the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit. Moreover, in this invention, unless it deviates from a claim and its equivalent range, a preferable aspect can be changed arbitrarily and implemented.

  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 preferred embodiment 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 by being controlled to be vertically oriented.

≪Optical film≫
The optical film of the present invention is provided with a hard coat layer on at least one surface of a transparent resin film containing a cycloolefin resin as a main component, and is represented by the general formula (I) with respect to the cycloolefin resin. And the in-plane retardation value Ro (550) measured at a wavelength of 550 nm of the transparent resin film is in the range of 90 to 170 nm. To 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)

  Examples of the cyclopolyolefin resin according to the present invention include the following (co) polymers.

〔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 represents a hydrogen atom, a hydrocarbon group, a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amide group, an imide group, a silyl group, or a polar group ( That is, it is a hydrocarbon group substituted with a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amide group, an imide group, or a silyl group. However, two or more of R ^{1 to} R ⁴ may be bonded to each other to form an unsaturated bond, a monocycle or a polycycle, and this monocycle or polycycle has a double bond. Alternatively, an aromatic ring may be formed. R ¹ and R ² , or R ³ and R ⁴ may form an alkylidene group. p and m are integers of 0 or more. ]

In the 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, 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 polar group having a polarity other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, and p is 0 to 3 More preferably, m + p = 0-4, more preferably 0-2, particularly preferably m = 1, p = 0. The specific monomer with m = 1 and p = 0 is preferred in that the resulting cyclopolyolefin resin has a high glass transition temperature and excellent mechanical strength.

Examples of the polar group of the specific monomer include a carboxy group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, and a cyano group. These polar groups have a linking group such as a methylene group. It may be bonded via. In addition, a hydrocarbon group in which a divalent organic group having a polarity such as a carbonyl group, an ether group, a silyl ether group, a thioether group, or an imino group is bonded as a linking group can also be exemplified. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or an allyloxycarbonyl 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 ) nCOOR is obtained by using a cyclopolyolefin resin having a high glass transition temperature, a low hygroscopic property, and various materials. It is preferable at the point which has the outstanding adhesiveness. In the formula relating to the specific polar group, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4, particularly preferably 1 to 2, and preferably an alkyl group.

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

  In this invention, cycloolefin resin can be used individually by 1 type or in combination of 2 or more types.

The preferred molecular weight of the cyclopolyolefin resin according to the present invention is 0.2 to 5 dl / g, more preferably 0.3 to 3 dl / g, particularly preferably 0.4 to 1.5 dl / g in terms of intrinsic viscosity [η] inh. The number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 8000 to 100,000, more preferably 10,000 to 80,000, particularly preferably 12,000 to 50,000, and the weight average molecular weight (Mw). Is preferably in the range of 20000 to 300,000, more preferably 30000 to 250,000, particularly preferably 40000 to 200000.

  Inherent viscosity [η] inh, number average molecular weight, and weight average molecular weight are within the above ranges, so that the heat resistance, water resistance, chemical resistance, mechanical properties of the cyclopolyolefin resin and molding as the cyclopolyolefin film of the present invention are as follows. Workability is improved.

  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., and particularly preferably 120 to 220 ° C. When Tg is less than 110 ° C., it is not preferable because it is deformed by use under a high temperature condition or by secondary processing such as coating or printing. On the other hand, when Tg exceeds 350 ° C., the molding process becomes difficult, and the possibility that the resin deteriorates due to heat during the molding process increases.

  For the cyclopolyolefin resin, a specific hydrocarbon resin or a known thermoplastic resin described in, for example, Japanese Patent Application Laid-Open No. 9-221777, Japanese Patent Application Laid-Open No. 10-287732, or the like, as long as the effects of the present invention are not impaired. Resins, thermoplastic elastomers, rubbery polymers, organic fine particles, inorganic fine particles, etc. may be blended, specific wavelength dispersing agents, sugar ester compounds, antioxidants, release accelerators, rubber particles, plasticizers, ultraviolet rays An additive such as an absorbent may be included.

  Commercially available products can be preferably used as the cyclopolyolefin resin described above. Examples of commercially available products are released under the trade names of Arton G, Arton F, Arton R, and Arton RX by JSR Corporation. These are commercially available from ZEON Corporation under the trade names of Zeonor ZF14, ZF16, Zeonex 250 or ZEONEX 280, and these can be used.

(Compound represented by 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. And by extending | stretching a transparent resin film, it is estimated that the planarity of the compound represented by general formula (I) orientates perpendicularly | vertically with respect to the thickness direction of an optical film, and the said oriented compound is an optical film. Precipitation of the contained compound is suppressed, moderate smoothness and formation of a uniform surface are enabled on the transparent resin film surface, and excellent adhesion between the transparent resin film and the hard coat layer is obtained.

（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 aromatics. L is a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. N is an integer of 0-2. .)

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

  In general, when the unsaturated bond is connected through a single bond or one or two linkages as in the compound represented by n = 0 to 2 in the general formula (I), π conjugate The structure can be seen. In particular, a single bond has a double bond property due to an interaction between unsaturated bonds. An electron (π electron) involved in a π bond of an unsaturated bond connected through a single bond or a bond is stable when it has a common π electron orbit. For this reason, even the electrons that have come to exist on a single bond or a bond are present in the same plane.

  The unsaturated bond in this case is not limited to those formed between carbon atoms, and includes those containing heteroatoms such as a carbonyl group. Furthermore, in a broad sense, examples showing a π-conjugated structure include those in which an unsaturated bond is connected by a functional group composed of an atom having an unshared electron pair such as an amino group or an ether group. The present invention is applicable to all structures having a π-conjugated structure known so far including these examples.

  A typical example of the π-conjugated structure is an aromatic ring structure. The aromatic ring structure in the present invention is a chemical structure defined as a general aromatic, in which unsaturated bonds contained in the structure are cyclically linked, such as benzene and naphthalene, Includes aromatic cyclic structures that are π-conjugated and planar structures. 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 a high coplanar π conjugation property can be obtained when R and R ′ are condensed rings. 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 orientation of 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 are a substituted or unsubstituted aryl group, or a heterocyclic group. L1 to L3 are a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. Each independently represents a carbon atom, a nitrogen atom, or an oxygen atom.)

  The 6-membered aromatics represented by A1 to A6 are, for example, benzene ring, pyrrole ring, pyrazole ring, imidazole ring, 1,2,3-triazole ring, 1,2,4-triazole ring, triazine ring, tetrazole And a ring, a furan ring, an oxazole ring, an isoxazole ring, an oxadiazole ring, an isoxadiazole ring, a thiophene ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, and an isothiadiazole ring. Among these, a benzene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, and a triazine ring are preferable from the viewpoint that the planarity of the compound can be obtained.

  In particular, the compound represented by the general formula (II) preferably has a structure represented by the general formula (III). Due to the steric repulsion of the CN bond of the triazine ring, an appropriate rotation barrier is generated in the single bond, carbon atom or nitrogen atom connecting the triazine ring and R1 to R3, and the planarity of the compound is easily obtained. From the viewpoint of the rotation barrier, at least one of L1 to L3 represented by the general formula (III) is preferably a single bond, and at least one of R1 to R3 is a substituted or unsubstituted benzene ring or pyrrole ring. , Pyrazole ring, imidazole ring, and triazine ring are preferable.

（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 are substituted or unsubstituted aryl groups or heterocyclic groups. L1 to L3 are 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 the general formula (III) is preferably a single bond, and at least one of R1 to R3 is preferably a benzene ring.

  R and R ′ in the general formula (1), or R1 to R3 in the general formula (II) and the general formula (III) may be the same aryl group or heterocyclic group, or may be different from each other.

  The aryl group is preferably phenyl or naphthyl, and 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, sulfonamido group, carbamoyl, alkyl-substituted carbamoyl group, alkenyl-substituted carbamoyl group, aryl-substituted carbamoyl group, amide group, alkylthio group, alkenyl A thio group, an arylthio group and an acyl group are included. The alkyl group has the same definition as the alkyl group described above. The alkyl part of 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 alkylthio group and the acyl group is the same as the alkyl group described above.

  The alkenyl group has the same definition as the alkenyl group described above. The alkenyl part of the alkenyloxy group, acyloxy group, alkenyloxycarbonyl group, alkenyl-substituted sulfamoyl group, sulfonamide group, alkenyl-substituted carbamoyl group, amide group, alkenylthio group and acyl group is the same as the alkenyl group described above.

  Examples of the aryl group include phenyl, α-naphthyl, β-naphthyl, 4-methoxyphenyl, 3,4-diethoxyphenyl, 4-octyloxyphenyl and 4-dodecyloxyphenyl. Examples of the aryloxy group, acyloxy group, aryloxycarbonyl group, aryl-substituted sulfamoyl group, sulfonamido group, aryl-substituted carbamoyl group, amide group, arylthio group, and acyl group are the same as the above 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 heterocyclic ring is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 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 the heterocyclic ring having aromaticity, a pyridine ring (2-pyridyl or 4-pyridyl as the heterocyclic group) 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.

  The heterocyclic group may be a heterocyclic group having a free valence on the nitrogen atom. The heterocyclic group having a free valence on the nitrogen atom is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring 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 other than the nitrogen atom (eg, O, S). 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.

  The aryl group or heterocyclic group may have a substituent, and when there are plural groups, 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 (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a tert- Butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl) Group), 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. , Bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3-yl), alke Group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group or an aryl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, That is, it is a monovalent group in which one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms has been removed, such as a 2-cyclopenten-1-yl or 2-cyclohexen-1-yl group, a 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 in which one hydrogen atom of a bicycloalkene having one double bond is removed. Bicyclo [2,2,1] hept-2-en-1-yl group, bicyclo [2,2,2] oct-2-en-4-yl group), alkynyl group Preferably, it is a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as an ethynyl group or a propargyl group, and an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms such as a phenyl group, p -Tolyl group, naphthyl group), a heterocyclic group (preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound, More preferably, it is a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as 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 1 to 30 carbon atoms, such as a methoxy group, an ethoxy group, an isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably a 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 silyloxy group having 3 to 20 carbon atoms, such as trimethylsilyloxy group, tert-butyldimethyl group) Silyloxy group), heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 1 to 30 carbon atoms, 1-phenyltetrazol-5-oxy group, 2-tetrahydropyranyloxy group), acyloxy group (Preferably a formyloxy group, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms. Killcarbonyloxy group, substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group) A carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms such as N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, for example, methoxycarbonyloxy group , Et Cicarbonyloxy group, tert-butoxycarbonyloxy group, n-octylcarbonyloxy group), aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxycarbonyl Oxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group), amino group (preferably amino group, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, carbon number 6-30 substituted or unsubstituted anilino groups such as amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably formylamino group, C1-C30 substituted or unsubstituted alkyl A carbonylamino group, a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group), aminocarbonylamino group (preferably, C1-C30 substituted or unsubstituted aminocarbonylamino group, for example, carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonylamino A group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as a methoxycarbonylamino group, an ethoxycarbonylamino group, a tert-butoxycarbonylamino group, an n-octadecyloxycarbo group; Ruamino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, such as phenoxycarbonylamino group, p-chlorophenoxy A carbonylamino group, an mn-octyloxyphenoxycarbonylamino group), a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as a sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, 6 to 30 carbon atoms) Substituted or unsubstituted arylsulfoni An amino group, such as a methylsulfonylamino group, a butylsulfonylamino group, a phenylsulfonylamino group, a 2,3,5-trichlorophenylsulfonylamino group, a p-methylphenylsulfonylamino group, a mercapto group, an alkylthio group (preferably, C1-C30 substituted or unsubstituted alkylthio group, for example, methylthio group, ethylthio group, n-hexadecylthio group), arylthio group (preferably C6-C30 substituted or unsubstituted arylthio group, for example, phenylthio group , P-chlorophenylthio group, m-methoxyphenylthio group), heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio group, 1- Phenyltetrazol-5-ylthio group), sulfamoyl group (preferably Preferably, the substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as 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 having 1 to 30 carbon atoms) An alkylsulfinyl group, a 6-30 substituted or unsubstituted arylsulfinyl group such as a methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably having a carbon number) 1-30 substituted or unsubstituted alkylsulfonyl , 6-30 substituted or unsubstituted arylsulfonyl groups such as methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group), acyl groups (preferably formyl group, C2-30 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 and a pivaloylbenzoyl group, and an aryloxycarbonyl group (preferably having 7 to 30 carbon atoms) A substituted or unsubstituted aryloxycarbonyl group such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group), alkoxycarbonyl group (preferably having 2 carbon atoms) ~ 30 substituted or unsubstituted alkoxy Bonyl group such as methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, n-octadecyloxycarbonyl group), carbamoyl group (preferably substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms such as carbamoyl Group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group), aryl and heterocyclic azo group (preferably having 6 carbon atoms) To 30 substituted or unsubstituted arylazo group, substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms, such as 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, such as dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group), phosphinyl group (preferably carbon A substituted or unsubstituted phosphinyl group having a number of 2 to 30, for example, a phosphinyl group, a dioctyloxyphosphinyl group, a diethoxyphosphinyl group, a phosphinyloxy group (preferably a substituted or substituted group having 2 to 30 carbon atoms) Unsubstituted phosphinyloxy group, for example, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, phosphinylamino group (preferably a substituted or unsubstituted phosphini group having 2 to 30 carbon atoms) Ruamino group, for example, 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 the functional group of the above substituent 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 the general formula (III) is preferably 260 ° C. or higher. The boiling point can be measured using a commercially available measuring device (for example, TG / DTA100, manufactured by SII Nano Technology).

  Moreover, in this invention, the compound which has a structure represented by general formula (I-III) can be used individually by 1 type, or can use 2 or more types together.

  The molecular weight of the compound having the structure represented by the general formula (I to III) is 100 from the viewpoint of compatibility between the compound and the solvent or cycloolefin resin, when the dry film thickness of the cyclopolyolefin film is 15 to 50 μm. It is preferable that it exists in the range of -3000, More preferably, it exists in the range of 100-800. Within the range of 100 to 800, precipitation of the compound itself and generation of bleed out can be suppressed, and the planar orientation control of the compound becomes easy. Furthermore, it has low volatility and can uniformly disperse the compound within the dope.

  The compound having the structure represented by the above general formulas (I to III) can be added to alcohols such as methanol, ethanol and butanol, organic solvents such as methylene chloride, methyl acetate, acetone and dioxolane, or a mixed solvent thereof. You may melt | dissolve and add to dope, or you may add directly in 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 in an arbitrary ratio.

  The amount of the compound having a structure represented by the general formulas (I to III) is not particularly limited as long as the effects of the present invention are achieved. From the viewpoints of prevention of bleeding out and precipitation, adhesion, and visibility, The range of 2 to 20% by mass is preferable with respect to the olefin resin, and the range of 3 to 10% by mass is more preferable.

(Additive)
As described above, the optical film of the present invention can 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 as in the case of the above compound, from the viewpoint that the compound having a structure represented by the general formulas (I to III) can easily suppress precipitation of the additive. preferable.

  As an arbitrary component, it is preferable from a viewpoint of improving light resistance to contain a ultraviolet absorber. The ultraviolet absorber is intended 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 in the range of -20%, more preferably in the range of 5-10%.

  The ultraviolet absorber preferably used in the present invention is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, or a triazine ultraviolet absorber, and particularly preferably a benzotriazole ultraviolet absorber or a benzophenone ultraviolet absorber.

For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and side Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc., and tinuvin 109, tinuvin 171, tinuvin 234, tinuvin 326, tinuvin 327, tinuvin 32
8, Tinuvins such as Tinuvin 928 and the like, which are all commercially available products manufactured by BASF Japan Ltd. and can be preferably used. Of these, halogen-free ones are preferred. You may contain multiple types of ultraviolet absorbers.

  The method of adding the UV absorber can be added to the dope after dissolving the UV absorber in an alcohol such as methanol, ethanol, butanol, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof. Or you may add directly in dope composition. Moreover, what does not melt | dissolve in an organic solvent like an inorganic powder should just add to a dope, after using a dissolver and a sand mill in an organic solvent and acetylcellulose, disperse | distributing.

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

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

(Transparent resin film molding method)
Examples of the method for forming the transparent resin film used as the optical film of the present invention include known methods such as a melt extrusion method, a solution casting 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, Examples include 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, and diethyl ether. These solvents may be used alone or in combination of two or more.

  When 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 boiling point of the mixed solvent in the dope and the compound The compound can be localized in the vicinity of the surface of the transparent resin film by utilizing the solubility of the functional group or the polarity of the functional group. By controlling the orientation of the planarity of the localized compound, moderate smoothness and uniform surface of the transparent resin film surface are effectively formed, and the effect of reducing the adhesion between the transparent resin film and the hard coat layer is effective. Is expected to be suppressed.

  Below, the method of localizing the compound which has a structure represented by general formula (I-III) in the solution casting method near the surface of a transparent resin film is demonstrated in detail.

  In one embodiment of utilizing the difference in 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 from the metal support, stretching or holding the width It has the process, the process of drying further, and the process of winding up the 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 surface opposite to the support to cause A distribution occurs in the thickness direction. In the case of a mixed solvent, since it volatilizes from a low boiling point, a distribution of a low boiling point and a high boiling point occurs in the thickness direction. At this time, localization of the compound occurs in the thickness direction in the film after drying due to the solubility of the compound having the structure represented by the general formula (I to III). When the compound having the structure represented by the general formulas (I to III) has higher solubility in a low-boiling solvent than the high-boiling solvent, the compound is in the direction of volatilization (surface opposite to the support). Since it is biased, it is localized near the surface. On the other hand, when the solubility is low, the compound is not biased with volatilization, so that it is difficult to localize.

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

  Moreover, when utilizing the polarity of the functional group of the compound having the structure represented by the general formula (I to III), for example, the compound having the structure represented by the general formula (I to III) is a functional group having a high polarity. When it has, it is hard to melt | dissolve in a dichloromethane and is easy to melt | dissolve in ethanol, Therefore It localizes biased to a support body 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. The load increases, and the filtration accuracy deteriorates. The concentration for achieving both of these is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass. The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.

  The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to a temperature below -50 ° C. to the point where it does not boil and foam. Higher temperatures are preferable because the web can be dried faster, but if the temperature is too high, the web may foam or flatness may deteriorate.

  A preferable support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for 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 hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using hot air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, hot air above the boiling point of the solvent may be used, and air at a temperature higher than the target temperature may be used while preventing foaming. .

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

  In order for the transparent resin film to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150 mass%, more preferably 20 to 40 mass% or 60 to 130 mass%. Especially preferably, it is 20-30 mass% or 70-120 mass%.

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

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

  Further, in the drying step of the transparent resin film, the web is peeled from the metal support, and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, Especially preferably, it is 0-0.01 mass% or less.

  In the film drying process, a roller drying method (a method in which webs are alternately passed through a plurality of rollers arranged above and below) and a method of drying while transporting the web by a tenter method are 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).

  When the compound enters the free volume between the resins or bonds with the resin, the resin is pulled during stretching, and at the same time, the compound is oriented in the stretching direction, with the compound surface aligned, and the stress is applied to the resin depending on the stretching ratio and stretching temperature. The orientation of the compound can be controlled by adjusting the direction and the resin hardness.

  There is no particular limitation on the stretching method. For example, a method in which a difference in peripheral speed is applied to a plurality of rollers, and the rollers are stretched in the longitudinal direction using the difference in peripheral speed between the rollers, and both ends of the web are fixed with clips and pins, and the interval between the clips and pins is widened in the traveling direction. And a method of stretching in the vertical direction, a method of stretching in the horizontal direction and stretching in the horizontal direction, a method of stretching in the vertical and horizontal directions and stretching in both the vertical and horizontal directions, and the like. Of course, these methods may be used in combination. That is, the film may be stretched in the transverse direction, in the longitudinal direction, in both directions, or may be stretched in both directions. May be. In the case of the so-called tenter method, driving the clip portion by the linear drive method is preferable because smooth stretching can be performed and the risk of breakage and the like can be reduced.

  In the present invention, in particular, stretching is performed in the transport direction using the peripheral speed difference of the film transport rollers, or both ends of the web are clipped in a direction orthogonal to the transport direction (also referred to as the width direction or the TD direction). It is preferable to use a tenter system in which the web is gripped by a left and right gripping means, and it is also preferable to use a tenter that can independently control the web gripping length (distance from the start of gripping to the end of gripping) left and right.

  In the present invention, both ends of the transparent resin film are stretched at an angle in the range of −90 to 0 ° with respect to the transport direction and at a stretch ratio in the range of 50 to 100%, and measured with light having a wavelength of 550 nm. 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 estimated that it is orientating so that the plane of the compound represented by general formula (I-III) may become perpendicular | vertical with respect to the thickness direction of a transparent resin film.

  In the present invention, a particularly preferred stretching method is that the tenter is stretched 1.03 to 1.30 times, preferably 1.05 to 1.20 times in the TD direction, and then 1.50 to 2.5 times obliquely. It is preferable to stretch. Before stretching in the oblique direction, the planarity and film thickness deviation of the film are improved by stretching in the width direction once.

  The temperature at which the film is obliquely stretched is preferably a 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. . Moreover, a draw ratio is 1.01-30 times normally, Preferably it is 1.01-10 times, More preferably, it is 1.01-5 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 setting such an orientation angle, in-plane retardation (Re) of the film can be made suitable.

The thickness of the transparent resin film after completion of the present invention (after drying) 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 20 to 110 μm for liquid crystal display devices. It is preferable that the thickness is 40 μm or less in view of recent thinning.
In order to reduce the thickness of the transparent resin film to 40 μm or less, it is generally necessary to increase the content of the additive in order to maintain the performance of the transparent resin film, and the bleeding out of the additive becomes a problem. Since the compound having the 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, the adhesion between the thin transparent resin film and the hard coat layer is improved. However, the structure of the present invention can be used effectively.

  The thickness of the film is adjusted so that the desired thickness and thickness distribution in the present invention are obtained, 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. You can adjust. 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 in the range of 0.8 to 2.5 m. The length is preferably wound 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 characteristics by appropriately adjusting the process conditions such as the polymer structure to be used, the type and amount of additives, the draw ratio, and the residual volatile content during peeling. . For example, the retardation value Rt in the thickness direction can be widely controlled to 180 to 300 nm by adjusting the residual solvent amount at the time of peeling within 40 to 85% by mass. In general, the larger the amount of residual solvent at the time of peeling, the smaller Rt, and the smaller the amount of residual solvent at the time of peeling, the larger Rt. For example, by shortening the drying time on a metal endless support and increasing the amount of residual solvent at the time of peeling, the surface orientation can be relaxed and Rt can be freely lowered, and by adjusting the process conditions It is possible to express various retardations according to various uses.

In the present specification, Ro and Rt each represent an in-plane retardation value and a retardation value in the thickness direction at the light wavelength λ. Ro is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rt is measured by making light having a wavelength of λ nm incident from a direction inclined + 40 ° with respect to the normal direction of the film, using the Ro, in-plane slow axis (determined by KOBRA 21ADH) as an inclination axis (rotation axis). Of the retardation value measured and the retardation value measured by injecting light of wavelength λ nm from the direction inclined −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis) KOBRA 21ADH is calculated based on the retardation values measured in two directions. Here, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. By inputting the assumed average refractive index values and thicknesses, KOBRA 21ADH calculates the retardation value on the basis of the following equation to calculate the _{n x, n y, n z} (i) and (ii).

Formula _{(i): Ro = (n} x -n y) × d (nm)
Formula _{(ii): Rt = {(} n x + n y) / 2-nz} × d (nm)
(Wherein, Ro represents a plane retardation value of the film, Rt represents the thickness direction of the retardation value in the film. Further, d, .n _x representing a thickness of the optical film (nm) represents the maximum refractive index in the plane of the film, slow .n _y, also referred to as the refractive index of the phase axis direction, .nz representing a direction perpendicular refractive index to the slow axis in the film plane, 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 improving contrast and improving luminance. The total light transmittance measured after humidity adjustment 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 according to JIS7573 “Plastics—How to obtain total light transmittance and total light reflectance”.

  In the transparent resin film according to the present invention, the equilibrium water content at 25 ° C. and relative humidity 60% is preferably 3% or less, and more preferably 1% or less from the viewpoint of phase difference fluctuation and bending. By setting the equilibrium moisture content to 3% or less, it is preferable to easily cope with a change in humidity and to hardly change the optical characteristics and dimensions.

  Equilibrium moisture content is determined by leaving the sample film in a room conditioned at 23 ° C. and 20% relative humidity for 4 hours or more and then leaving it in a room conditioned at 23 ° C. and 80% RH for 24 hours. Using a meter (for example, CA-20 model manufactured by Mitsubishi Chemical Analytech Co., Ltd.), moisture is dried and vaporized at a temperature of 150 ° C., 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 a hard coat layer, the impact resistance and ease of handling of the optical film can be improved.

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

  Examples thereof include organic hard coat materials such as organic silicone, melamine, epoxy, acrylate, and polyfunctional (meth) acrylic compounds; inorganic hard coat materials such as silicon dioxide; and the like. Among these, from the viewpoint of good adhesion and excellent productivity, it is preferable to use a hard coat forming material of a (meth) acrylate-based or polyfunctional (meth) acrylic-based compound. Here, (meth) acryl means acryl and methacryl.

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

  Moreover, in the hard-coat layer which concerns on this invention, various additives can be further mix | blended as needed in the range which does not impair the effect of this invention. For example, an antioxidant, an ultraviolet stabilizer, an ultraviolet absorber, a surfactant, a leveling agent, an antistatic agent and the like can be used. The hard coat layer of the present invention is a particle having an average particle size of 0.2 to 10 μm. The antiglare property may be imparted by containing a high refractive index fine particle in a dispersed manner, and the refractive index may be imparted.

  The leveling agent is particularly effective in reducing surface irregularities when a hard coat layer is applied. As the leveling agent, for example, a dimethylpolysiloxane-polyoxyalkylene copolymer is suitable as a silicone leveling agent.

  As the 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), and oxidation. Examples thereof include at least one selected from the group consisting of tin, indium oxide, tungsten oxide, composite tungsten oxide, and antimony oxide. Among these, silica fine particles are preferred because the effect of improving the surface hardness can be particularly increased and the strength can be particularly increased. In addition, from the viewpoint of adding ultraviolet absorption performance to the hard coat layer and suppressing deterioration with time of the hard coat layer, it is preferable to use ITO, ATO, tungsten oxide, or composite tungsten oxide.

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

  Examples of the UV absorber include salicylic acid UV absorbers, benzophenone UV absorbers, benzotriazole UV absorbers, cyanoacrylate UV absorbers, triazine UV absorbers, and benzoxazinone UV absorbers. 1 type or 2 types or more selected from these groups can be used. Among these, from the viewpoint of dispersibility, triazine-based UV absorbers and benzoxazinone-based UV absorbers are preferable. Moreover, as the ultraviolet absorber, a polymer having an ultraviolet absorbing group in the molecular chain is also preferably used. By using a polymer having an ultraviolet absorbing group in such a molecular chain, it is possible to prevent deterioration of the ultraviolet absorbing function due to bleeding out of the ultraviolet absorbent. Examples of the ultraviolet absorbing group include a benzotriazole group, a benzophenone group, a cyanoacrylate group, a triazine group, a salicylate group, and a benzylidene malonate group. Among these, a benzotriazole group, a benzophenone group, and a triazine group are particularly preferable.

The method of forming the hard coat layer is not particularly limited, and the coating liquid of the hard coat forming material is a dipping method, a spray method, a slide coat method, a bar coat method, a roll coater method, a die coater method, a gravure coater method, screen printing. After coating on an optical film containing an alicyclic structure-containing polymer by a known method such as the method, and drying under an atmosphere such as air or nitrogen, an acrylic hard coat material is applied and ultraviolet rays are applied. It is carried out by crosslinking and curing with an electron beam or the like, or by applying a silicone-based, melamine-based, or epoxy-based hard coat material and thermally curing. Since unevenness of the coating film thickness is likely to occur during drying, it is preferable to control the intake and exhaust air so as not to impair the appearance of the coating film so that the entire coating film surface is uniform. In the case of using a material that is cured by ultraviolet rays, the irradiation time for curing the hard coat forming material after coating by ultraviolet irradiation is usually in the range of 0.01 to 10 seconds, and the irradiation amount of the energy beam source is an ultraviolet wavelength of 365 nm. of accumulative exposure in a range of usually 40 mJ / cm ² of 1000 mJ / cm ^2. Further, the irradiation of ultraviolet rays may be performed in an inert gas such as nitrogen and argon, or may be performed in the air.

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

≪Application of optical film≫
The optical film of the present invention is preferably a functional film used for various display devices such as liquid crystal displays, plasma displays, organic EL displays, and touch panels. Specifically, the optical film of the present invention is a polarizing plate protective film for liquid crystal display devices, a retardation film, an antireflection film, a brightness enhancement film, a hard coat film, an antiglare film, an antistatic film, an enlarged viewing angle, etc. Or an optical compensation film. Typically, the optical film of the present invention is a polarizing plate protective film, a retardation film, or an optical compensation film. The optical film of the present invention can serve as both a retardation film and a polarizing plate protective film.

  Hereinafter, the present invention will be described in more detail with reference to examples. The materials used are as follows.

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

(Comparative compound)
Compound 5: Triphenyl phosphate

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

The SP value in the present invention can be obtained by calculation using the Fedors parameter. The unit of SP value is the square root of the value obtained by dividing the cohesive energy density ΔE by the molar volume V, and “(cm ³ / cal) ^1/2 ” can be used. The parameters of Fedors are described in References: Basic Science of Coatings by Yuji Harada, Kashiwa Shoten (1977), p54-57.

<< Production of optical film 1 >>
<Preparation of hard coat layer coating solution 1>
A hard coat layer coating solution 1 having the following composition was prepared. After mixing an ultraviolet curable resin, a surfactant, and propylene glycol monomethyl ether, the mixed solution was stirred for 30 minutes to prepare a hard coat layer coating solution 1.

UV curable resin (OPSTAR Z7527, manufactured by JSR) 100 parts by mass Surfactant (Surflon S-651, manufactured by AGC Seimichemical Co., Ltd.) 0.1 parts by mass Methyl ethyl ketone 30 parts by mass

<Preparation of hard coat layer coating solution 2>
A hard coat layer coating solution 2 having the following composition was prepared in the same manner as the hard coat layer coating solution 1.

UV curable resin (Opster Z7527 manufactured by JSR) 100 parts by mass Surfactant (Surflon S-651 manufactured by AGC Seimichemical Co.) 0.1 part by mass Methyl ethyl ketone 20 parts by mass

<Preparation of hard coat layer coating solution 3>
A hard coat layer coating solution 3 having the following composition was prepared in the same manner as the hard coat layer coating solution 1.

UV curable resin (OPSTAR Z7527, manufactured by JSR Corporation) 100 parts by weight Surfactant (Surflon S-651, manufactured by AGC Seimichemical Co., Ltd. 0.1 parts by weight Methyl ethyl ketone 30 parts by weight PMMA particles (manufactured by Sekisui Plastics Co., Ltd.) 2.0μm) 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 stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

  To a well-stirred methylene chloride (100 parts by mass) in a dissolution tank, 5 parts by mass of the fine particle dispersion was slowly added. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.

<Preparation of main dope>
A main dope having the following composition was prepared. First, dichloromethane and ethanol were added to the pressure dissolution tank. The cycloolefin resin, the compound 1, the ultraviolet absorber, and the fine particle addition liquid were added to a pressure dissolution tank containing a mixed solution of dichloromethane and ethanol with stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope was prepared by filtration using 244.

Cycloolefin resin (ARTON G7810, manufactured by JSR Co., Ltd.) 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 Particulate additive solution 3 parts by mass

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

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

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

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

<< Production of optical films 2-24 >>
The structure shown in Table 2 was produced in the same manner as the optical film 1.

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

<Surface hardness>
Using the test pencils specified in JIS-S6006, optical films 1 to 24 are repeatedly scratched 5 times with a pencil of each hardness using a 500 g weight according to the pencil hardness evaluation method specified in JIS-K5400. The hardness until one scratch was made was measured. The higher the number, the higher the hardness.

<Adhesion>
After conditioning the optical films 1 to 24 in an atmosphere of 23 ° C. and 55% RH for 12 hours, eleven slits are formed vertically and horizontally at 1 mm intervals on the hard coat layer surface of the optical films 1 to 24 by a method according to JISK5400. A 100 mm grid was prepared with 1 mm square, and a cellophane tape was affixed and peeled off quickly at an angle of 90 degrees. The cellophane tape was evaluated according to the following criteria from the area of the grids remaining without peeling after performing the tape peeling operation 6 times while changing the tape every time it was peeled.

A: Not peeled at all O: Area ratio of peeled grids was less than 5% Δ: Area ratio of peeled grids was less than 10% ×: Area of peeled grids The ratio was 10% or more

<Evaluation of point defects>
The optical films 1 to 24 were incorporated into a liquid crystal display device, and the black and white dots or spots that were concentrated locally were observed visually and evaluated according to the following criteria. In addition, if it is more than (triangle | delta), it can use for practical use.

◎: No light omission and uniform dark field on the whole ○: Partially very light and dark △: Overall, slightly bright and dark, but practically no problem.
×: Brightness and darkness are recognized throughout

<< Production of Polarizing Plates 1-24 >>
The polarizing plate can be produced by a general method. After the produced optical films 1 to 24 are subjected to alkali saponification treatment,
A fully saponified polyvinyl alcohol 5% aqueous solution was used as an adhesive and was bonded to both sides of the polarizer. At that time, the polarizing plates 1 to 24 were produced by bonding them so 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 were coincident with each other.

<< Production of liquid crystal display devices 1 to 24 >>
The polarizing plate on the viewing side, which was previously bonded to a commercially available IPS liquid crystal display device, was peeled off, and the above-prepared polarizing plates 1 to 24 were bonded to the glass surface of the liquid crystal cell (IPS type). Produced. At that time, the polarizing plate is placed so that the produced optical films 1 to 24 are on the display surface side, and the polarizing plate is bonded in the same direction as the polarizing plate that has been bonded in advance. Cut out.

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

<Evaluation of visibility when wearing sunglasses>
An image was displayed on a liquid crystal display device, visually observed by a subject wearing sunglasses, and evaluated according to the following criteria.
A: Even if the observation angle is changed, there is no difference in how the image looks.
○: The screen slightly darkens depending on the viewing angle. Δ: The screen looks slightly dark or distorted depending on the viewing angle. X: The screen appears darker or distorted depending on the viewing angle.

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

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

  Moreover, when content of the compound which has a structure represented by general formula (I) like the optical films 19 and 20 does not satisfy the requirements of this invention, it is represented by the added ultraviolet absorber or general formula (I). It was found that precipitation of the compound having the structure shown above or the effect of the compound having the structure represented by the general formula (I) could not be sufficiently achieved, and the adhesion and surface hardness were poor.

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

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

DESCRIPTION OF SYMBOLS 1 Optical film 2 Transparent resin film 3 Hard-coat layer 4 Example of compound which has a structure represented by general formula (I)

Claims (11)

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,
Containing a compound having a structure represented by the general formula (I) with respect to the cycloolefin resin within a range of 2 to 20% by mass;
An in-plane retardation value Ro (550) measured with light having a wavelength of 550 nm of the transparent resin film is in the range of 90 to 170 nm.

(R and R ′ are substituted or unsubstituted 6-membered aromatic groups;
L is a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. ;
n is an integer of 0-2. ) The optical film according to claim 1, wherein the compound having a structure represented by the general formula (I) is a compound having a structure represented by the general formula (II).

(R1 to R3 are a substituted or unsubstituted aryl group or a heterocyclic group;
L1 to L3 are a single bond or a divalent linking group containing a carbon atom or a nitrogen atom. ;
A1 to A6 are each independently a carbon atom, a nitrogen atom, or an oxygen atom. )   The optical film according to claim 2, wherein in the general formula (II), the 6-membered aromatic group represented by A1 to A6 is a triazine ring group.   In the said general formula (II), at least one of L1-L3 is a single bond, The optical film of Claim 2 or 3 characterized by the above-mentioned.   In the general formula (II), at least one of R1 to R3 is substituted with a substituted or unsubstituted aromatic hydrocarbon ring group or aromatic heterocyclic group. The optical film according to one item.   The said transparent resin film contains the ultraviolet absorber, The optical film as described in any one of Claims 1-5 characterized by the above-mentioned.   The thickness of the said transparent resin film is 40 micrometers or less, The optical film as described in any one of Claims 1-6 characterized by the above-mentioned.   The method for producing an optical film according to any one of claims 1 to 7, wherein the transparent resin film is formed by a solution pouring method.   The both ends of the said transparent resin film are extended | stretched by the angle within the range of -90-0 degree with respect to a conveyance direction, and the draw ratio within the range of 50-100%. Manufacturing method of optical film.   A polarizing plate comprising the optical film according to claim 1.   A display device comprising the polarizing plate according to claim 10.

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