JP2016212146A - Optical film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film having a high surface hardness, excellent scratch resistance and a low haze, and a method for manufacturing the optical film.SOLUTION: The optical film is an optical film 1 having a hard coat layer 3 on a resin layer 2 comprising a cycloolefin resin. The resin layer 2 contains a low molecular weight compound having a weight average molecular weight Mw ranging from 100 to 10000 within a range from 0.1 to 5.0 mass% with respect to the cycloolefin resin; and the hard coat layer 3 comprises a UV curing resin and silica particles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical film having high surface hardness, excellent scratch resistance and low haze, and a method for producing the same.

  In recent years, there has been a strong demand for display devices that are large in size, thinned, flexible, and the like.

  A polarizing plate to be combined with an image display device equipped with an organic electroluminescence element (hereinafter also referred to as an organic EL element) generally has a configuration in which a polarizer is disposed between two protective films, and is reflected by the polarizing plate. In order to add a prevention function, a protective film provided with a phase difference on the organic EL element side is used. A liquid crystal display (LCD) includes a liquid crystal cell and a pair of polarizing plates that sandwich the liquid crystal cell. Among the polarizing plates used in these display devices, in particular, the polarizing plate on the viewing side is required to have high scratch resistance in order to prevent the surface from being scratched.

  Conventionally, a cellulose acetate film has been widely used as a base film. However, this film has a drawback of having hygroscopicity and moisture permeability. Cycloolefin-based resins are notable for these disadvantages and have good water resistance, heat resistance, transparency, dimensional stability, and the like, and thus are attracting attention as excellent thermoplastic resins for protective films. However, when a cycloolefin resin is used as an optical film, there is a problem that the surface hardness is not sufficient and the surface is easily scratched.

  As a countermeasure, it has been studied to increase the surface hardness of the optical film used for the polarizing plate on the viewing side. In order to increase the surface hardness of the optical film, as a technique for laminating a hard coat layer on a base film, for example, in Patent Document 1, a hard coat layer on a cycloolefin film is allowed to contain fine particles, whereby Techniques for improving blocking properties and scratch resistance are disclosed. Patent Document 2 discloses a production method for producing a cycloolefin polymer film through a contact process with a solvent that satisfies a specific condition before application of a hard coat layer.

  However, these techniques have not been sufficient for increasing the surface hardness and improving the scratch resistance of an optical film in which a hard coat layer is provided on a substrate made of a cycloolefin resin.

JP 2013-186236 A JP 2014-70211 A

  The present invention has been made in view of the above-described problems and circumstances, and a problem to be solved is to provide an optical film having high surface hardness, excellent scratch resistance, and low haze. Moreover, it is providing the manufacturing method.

In order to solve the above-mentioned problems, the inventor made the hard coat layer contain an ultraviolet curable resin and silica particles in the course of examining the cause of the above-mentioned problem, and further specified the cycloolefin resin of the base film. It has been found that the inclusion of an amount of a low molecular weight compound can increase the surface hardness of the optical film and greatly improve the scratch resistance, leading to the present invention.

  That is, the said subject which concerns on this invention is solved by the following means.

  1. An optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer is a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. On the other hand, the optical film is contained within a range of 0.1 to 5.0% by mass, and the hard coat layer contains an ultraviolet curable resin and silica particles.

  2. 2. The optical film as set forth in claim 1, wherein the low molecular weight compound contained in the resin layer is an ultraviolet absorber.

3. The mass ratio of the silica particles to the ultraviolet curable resin (silica particles / ultraviolet curable resin) contained in the hard coat layer is in the range of 10/90 to 50/50. Item 3. The optical film according to Item 1 or Item 2.
4). The average primary particle size of the silica particles is 200 nm or less, The optical film according to any one of items 1 to 3, wherein

  5. The thickness of the said hard-coat layer exists in the range of 2-15 micrometers, The optical film as described in any one of Claim 1 to 4 characterized by the above-mentioned.

In the environment of 6.23 ° C. and 55% RH, the retardation value (Ro (550)) in the in-plane direction at a light wavelength of 550 nm satisfies the following formula (1): The optical film as described in any one of the above.
Formula (1): 100 nm ≦ Ro (550) ≦ 170 nm
7). A production method for producing an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer contains a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. It contains in the range of 0.1-5.0 mass% with respect to cycloolefin type resin, the said hard-coat layer contains a ultraviolet curable resin and a silica particle, and the said ultraviolet curable resin and the said silica particle are included. Production of an optical film characterized by forming a hard coat layer through a step of applying a coating solution prepared using at least two solvents of alcohol, ester, ether or ketone as a solvent for the coating solution to be contained Method.

  8). A production method for producing an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer contains a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. Resin which contains in the range of 0.1-5.0 mass% with respect to cycloolefin type resin, the said hard-coat layer contains ultraviolet curing resin and a silica particle, and contains the said cycloolefin type resin A method for producing an optical film, wherein the resin layer is formed by casting a solution in which the solution is dissolved on a substrate to form a film.

  9. 9. The method for producing an optical film according to item 8, wherein the resin layer is formed through a step of unwinding the original film wound after the film formation and stretching it in an oblique direction.

  By the above means of the present invention, an optical film having high surface hardness, excellent scratch resistance and low haze can be provided. Moreover, the manufacturing method can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  The surface hardness can be greatly increased by adding a specific amount of a low molecular weight compound to the cycloolefin resin of the base film. By adding a low molecular weight compound to the cycloolefin resin, the free volume of the cycloolefin resin can be increased. This is because this additive can be filled with good compatibility and the density of the resin layer increases. Furthermore, it is presumed that an optical film having high surface hardness and excellent scratch resistance can be realized by containing an ultraviolet curable resin and silica particles in the hard coat layer.

Example of optical film configuration An example of a tenter that can be stretched diagonally Example of configuration of liquid crystal display device

  The optical film of the present invention is an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, and the resin layer has a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. In the range of 0.1 to 5.0% by mass with respect to the cycloolefin-based resin, and the hard coat layer contains an ultraviolet curable resin and silica particles. This feature is a technical feature common to the inventions according to claims 1 to 9.

  As an embodiment of the present invention, it is preferable that the low molecular weight compound contained in the resin layer is an ultraviolet absorber from the viewpoint of manifesting the effects of the present invention. Moreover, it is high surface that the value (silica particle / ultraviolet curable resin) of the mass ratio of the said silica particle with respect to the said ultraviolet curable resin contained in a hard-coat layer exists in the range of 10 / 90-50 / 50. This is preferable for achieving both hardness and low haze. In addition, the average primary particle size of the silica particles is preferably 200 nm or less from the viewpoint of achieving both haze and scratch resistance.

  Furthermore, it is preferable that the thickness of the hard coat layer is in the range of 2 to 15 μm because the polarizing plate tends to be thinned.

  In addition, in an environment of 23 ° C. and 55% RH, the in-plane retardation value (Ro (550)) at an optical wavelength of 550 nm satisfies the above formula (1) for antireflection applications of organic electroluminescence elements. It is preferable for use as a protective film.

  Furthermore, as a method for producing an optical film for producing the optical film of the present invention, a method for producing an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer is A low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000 is contained in a range of 0.1 to 5.0% by mass with respect to the cycloolefin resin, and the hard coat layer is an ultraviolet curable resin and silica. And a step of applying a coating solution prepared using at least two solvents of alcohol, ester, ether or ketone as a solvent for the coating solution containing particles and the ultraviolet curable resin and the silica particles. It is preferable to form a hard coat layer through this.

  Moreover, it is preferable that it is a manufacturing method which forms the said resin layer by forming into a film through the process of casting the solution which melt | dissolved resin containing cycloolefin type resin on a base | substrate. Furthermore, it is preferable that it is a manufacturing method which forms the resin layer through the process of unwinding the film raw material wound up after film forming, and extending | stretching in the diagonal direction.

  Hereinafter, the present invention, its components, and modes and modes for carrying out 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.

<Outline of optical film>
The optical film of the present invention is an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, and the resin layer has a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. In the range of 0.1 to 5.0% by mass with respect to the cycloolefin-based resin, and the hard coat layer contains an ultraviolet curable resin and silica particles.

  FIG. 1 is an example of the optical film of the present invention. The optical film 1 of the present invention has a hard coat layer 3 on the resin layer 2 using the resin layer 2 as a base film.

  The thickness of the optical film 1 is preferably in the range of 10 to 100 μm. More preferably, it exists in the range of 15-50 micrometers. Moreover, it is preferable that the thickness of a hard-coat layer exists in the range of 2-15 micrometers, and it is more preferable that it exists in the range of 2-8 micrometers.

  The present inventor has found a phenomenon that the surface hardness of the cycloolefin film is increased by incorporating a low molecular weight compound into the cycloolefin resin. Such a phenomenon is not observed in the cellulose ester resin and is a characteristic of the cycloolefin resin. Thus, although the phenomenon that the surface hardness increases is not clear, it is presumed that the density of the base material is increased by filling the free volume of the resin with these additives with good compatibility. For this reason, it is guessed that the scratch resistance of the optical film of the present invention having a hard coat layer is improved.

<Low molecular weight compound>
The optical film of the present invention is an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, and the resin layer has a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. In the range of 0.1 to 5.0% by mass with respect to the cycloolefin-based resin.

  When the weight average molecular weight Mw of the low molecular weight compound added to the cycloolefin-based resin is less than 100, the surface hardness cannot be increased. Moreover, when it exceeds the weight average molecular weight Mw10000, haze will become high. Preferably, the weight average molecular weight Mw of the low molecular weight compound is in the range of 300-2500. In the present invention, when the low molecular weight compound is not a polymer, the weight average molecular weight represents the molecular weight of the low molecular weight compound.

  By adding 0.1% by mass or more of these low molecular weight compounds to the cycloolefin resin, the surface hardness of the cycloolefin resin can be increased. Even if the addition amount exceeds 5.0% by mass, the surface hardness decreases and haze also increases, which is not preferable. Preferably, the low molecular weight compound is added within a range of 0.5 to 3% by mass with respect to the cycloolefin-based resin.

  Although there is no restriction | limiting in particular in the low molecular weight compound in the range whose weight average molecular weight Mw is 100-10000, It is preferable to be chosen from the group of the compound which has a ultraviolet absorber, a polyester-type compound, and a furanose structure or a pyranose structure. Preferably, the low molecular weight compound is an ultraviolet absorber.

<Ultraviolet absorber>
Specific examples of ultraviolet absorbers preferably used in the present invention include, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, and the like. However, it is not particularly limited to these, and other ultraviolet absorbers are also used. Of these, benzotriazole compounds are preferred.

  As the benzotriazole ultraviolet absorber, a compound represented by the following general formula (1) can be used.

In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, and are a hydrogen atom, halogen atom, nitro group, hydroxy group, alkyl group, alkenyl group, aryl group, alkoxy group, acyloxy. Represents a group, aryloxy group, alkylthio group, arylthio group, mono- or dialkylamino group, acylamino group or 5- to 6-membered heterocyclic group, and R ₄ and R ₅ are closed to form a 5- to 6-membered carbocyclic ring May be.

  Although the specific example of the ultraviolet absorber of the benzotriazole type compound represented by General formula (1) below is given, this invention is not limited to these.

  2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3) '-Tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy -3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethyl) Butyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl)- - chlorobenzotriazole, in commercially available products, BASF Japan Ltd. TINUVIN 928, TINUVIN 109 and TINUVIN 171, and the like.

  Moreover, as a benzophenone type ultraviolet absorber which is one of the ultraviolet absorbers concerning this invention, the compound represented by following General formula (2) can be used.

In the formula, Y represents a hydrogen atom, a halogen atom or an alkyl group, an alkenyl group, an alkoxy group, and a phenyl group, and these alkyl group, alkenyl group, and phenyl group may have a substituent. A represents a hydrogen atom, an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an alkylcarbonyl group, an alkylsulfonyl group or a —CO (NH) _n−1 -D group, and D represents an alkyl group, an alkenyl group or a substituent. Represents a phenyl group which may have m and n represent 1 or 2.

  In the above, the alkyl group represents, for example, a linear or branched aliphatic group having up to 24 carbon atoms, the alkoxy group has, for example, an alkoxy group having up to 18 carbon atoms, and the alkenyl group has, for example, up to 16 carbon atoms. Represents an allyl group, a 2-butenyl group, or the like. In addition, as substituents for alkyl groups, alkenyl groups, and phenyl groups, halogen atoms such as chloro, bromo, fluorine atoms, hydroxy groups, phenyl groups (this phenyl group is substituted with alkyl groups or halogen atoms, etc.). May be included).

  Specific examples of the benzophenone-based compound represented by the general formula (2) are shown below, but the present invention is not limited thereto.

2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane)
In the present invention, an ultraviolet absorber having three or more aromatic rings (for example, benzene ring) or cycloalkyl rings (for example, cyclohexane ring) in the molecule is particularly preferable.

  Although it does not restrict | limit especially as a triazine type ultraviolet absorber, For example, 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4- Diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphene) ) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2- Hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, [2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol] (tinuvin 1577FF, manufactured by BASF Japan Ltd.), [2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol] (CYASORB UV -1164, manufactured by Cytec Industries), Tinuvin 405 (manufactured by BASF Japan), and the like.

<Polyester compound>
The polyester compound used in the present invention is preferably a polyester compound obtained by condensation polymerization with at least one benzene monocarboxylic acid and at least one alkylene glycol having 2 to 12 carbon atoms. More preferably, it is a polyester compound obtained by condensation polymerization of phthalic acid, adipic acid, at least one benzene monocarboxylic acid and at least one alkylene glycol having 2 to 12 carbon atoms. Examples of the acid component include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid, and the like. Each of these can be used as one kind or a mixture of two or more kinds. Most preferred is benzoic acid.

  Examples of the alkylene glycol component having 2 to 12 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, trimethylolethane, 1,2-butanediol, 1,3-butanediol, 1,2 -Propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2 -Diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3propanediol (3,3-dimethylolheptane), 3-methyl-1, 5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl There are 1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Used as a mixture of two or more. 1,2-propylene glycol is particularly preferable.

  These polyester compounds preferably have an adipic acid residue and a phthalic acid residue as the final compound structure. When manufacturing such a polyester-type compound, you may make it react as an acid anhydride or esterified substance of dicarboxylic acid. Such polyester compounds can be synthesized with reference to JP-A-2008-69225, JP-A-2008-88292, JP-A-2008-115221, and the like.

<Compound having furanose structure or pyranose structure>
The compound having a furanose structure or pyranose structure according to the present invention has at least one furanose structure or pyranose structure, and all or part of the hydroxy groups in the compound having 1 to 12 furanose structures or pyranose structures bonded thereto. A sugar ester obtained by esterification of A sugar ester obtained by esterifying all of the hydroxy groups is preferable.

  Examples of preferable “compounds having at least one furanose structure or pyranose structure and having 1 to 12 furanose structures or pyranose structures bonded to each other” include the following, for example. It is not limited to these.

  Glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, cellobiose, cellotriose, maltotriose, raffinose and the like can be mentioned, and those having both a furanose structure and a pyranose structure are particularly preferable. An example is sucrose.

《Cycloolefin resin》
The optical film of the present invention has a resin layer containing a cycloolefin resin. Examples of the cycloolefin resin according to the present invention include (co) polymers having the following structure.

(In the formula, R ^{1 to} R ⁴ are each independently 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, provided that two or more of R ^{1 to} R ⁴ are They may be bonded to each other to form an unsaturated bond, a monocycle or a polycycle, and this monocycle or polycycle may have a double bond or an aromatic ring. ¹ and R ² , or R ³ and R ⁴ may form an alkylidene group, and p and m are integers of 0 or more.)
In the general formula (3), R ¹ and R ³ represent a hydrogen atom or a hydrocarbon group having 1 to 10, more preferably 1 to 4, and particularly preferably 1 to 2 carbon atoms. R ² and R ⁴ are a hydrogen atom or a monovalent organic group, and 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, p is an integer of 0 to 3, more preferably m + p = 0 to 4, more preferably 0 to 2, particularly preferably m = 1 and p = 0. The specific monomer with m = 1 and p = 0 is preferable in that the cycloolefin resin obtained 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, the monomer in which at least one of R ² and R ⁴ is a polar group represented by the formula — (CH ₂ ) _n COOR is a cycloolefin-based resin that has a high glass transition temperature, low hygroscopicity, and various materials. It is preferable at the point from which it 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, dicyclopentadiene and norbornene.

  The number of carbon atoms of the cycloolefin is preferably 4-20, and more preferably 5-12.

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

The preferred molecular weight of the cycloolefin 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 20000 to 300000, more preferably 30000 to 250,000, and 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 heat resistance, water resistance, chemical resistance, mechanical properties of cycloolefin resin, and molding processability as cycloolefin film Becomes better.

  The glass transition temperature (Tg) of the cycloolefin 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.

  The optical film has a resin layer containing a cycloolefin-based resin as a base film. It is preferable that 50 mass% or more in a resin layer is a cycloolefin type resin, More preferably, it exists in the range of 80-99 mass%.

  For the cycloolefin resin, a specific hydrocarbon resin described in, for example, Japanese Patent Application Laid-Open Nos. 9-221777 and 10-287732, or a known heat can be used as long as the effects of the present invention are not impaired. An additive such as a plastic resin, a thermoplastic elastomer, a rubbery polymer, or rubber particles may be included.

  Commercially available products can be preferably used as the cycloolefin resin described above. Examples of commercially available products are commercially available from JSR Corporation under the trade names Arton G, Arton F, Arton R, and Arton RX. 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.

<Fine particles>
In order to impart surface slipperiness and the like to the resin layer that is the base film, fine particles (mat agent) can be contained within a range that does not impair the effects of the present invention. The fine particles may be composed of an inorganic compound or a resin.

  Examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, etc. Is mentioned.

  Examples of the resin include a silicone resin, a fluororesin, and an acrylic resin. Among them, silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120 and 240 (manufactured by Toshiba Silicone Co., Ltd.) What is marketed with a brand name is mentioned.

  Among these, fine particles of silicon dioxide are preferable in that the turbidity of the film can be lowered. Examples of fine particles of silicon dioxide include Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) and friction while keeping the film haze low. Aerosil 200V and Aerosil R972V are preferred because the effect of lowering the coefficient is great.

《Hard coat layer》
The optical film of the present invention has a hard coat layer on a resin layer containing a cycloolefin-based resin, and the hard coat layer contains an ultraviolet curable resin and silica particles. By having a hard coat layer on a resin layer having a high surface hardness, it is possible to improve the impact resistance and ease of handling of the optical film.

<UV curable resin>
As the ultraviolet curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used. By irradiating with ultraviolet rays, a hard coat layer having excellent mechanical film strength (abrasion resistance, pencil hardness) can be formed.

  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 adhesive force and excellent productivity, it is preferable to use a hard coat forming material of (meth) acrylate-based and polyfunctional (meth) acrylic-based compounds. 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. For example, pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, dipentaerythritol polyfunctional methacrylate, or the like can be used as the polyfunctional acrylate. (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 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 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.

<Silica particles>
In the optical film of the present invention, the hard coat layer contains silica particles. The mass ratio of the silica particles to the ultraviolet curable resin (silica particles / ultraviolet curable resin) contained in the hard coat layer is preferably in the range of 10/90 to 50/50. A value of this ratio is preferably 10/90 or more from the viewpoint of increasing the hardness of the hard coat layer, and is preferably 50/50 or less from the viewpoint that haze and scratch resistance are not deteriorated.

  The silica particles preferably have an average primary particle size of 200 nm or less in order to achieve both haze and surface hardness. Preferably it is 5-100 nm, More preferably, it exists in the range of 10-50 nm.

  Silica particles also have an increased surface hardness even when the particle surface is untreated, but the surface is coated with an organic component and a reactive polymerizable unsaturated group introduced by the organic component on the surface. It is preferable that it is the silica particle which has.

(Reactive silica particles coated with a polymerizable unsaturated group-containing compound)
As silica particles having an average primary particle size of 5 to 200 nm preferably used in the present embodiment, at least a part of the surface is coated with an organic component, and a reactive polymerizable unsaturated group introduced by the organic component is formed on the surface. The silica particle which has is mentioned.

  Known silica particles that are not surface-modified can be used. The shape may be spherical or indefinite, and is not limited to normal colloidal silica, and may be hollow particles, porous particles, core / shell particles, or the like, but colloidal silica is preferred.

  The dispersion medium of silica particles is preferably water or an organic solvent. Examples of organic solvents include alcohols such as methanol, isopropyl alcohol, ethylene glycol, butanol and ethylene glycol monopropyl ether; ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; dimethylformamide and dimethyl Examples include amides such as acetamide and N-methylpyrrolidone; esters such as ethyl acetate, butyl acetate and γ-butyrolactone; and organic solvents such as ethers such as tetrahydrofuran and 1,4-dioxane. Alcohols and ketones are preferred. These organic solvents can be used alone or in combination as a dispersion medium.

  Examples of commercially available products include, for example, IPA-ST, IPA-ST-L, IPA-ST-ZL, MEK-ST-L, MEK-ST-MS manufactured by Nissan Chemical Industries, Ltd., as colloidal silica. it can.

  Reactive silica particles are obtained by surface-treating colloidal silica as described above with an organic compound having a reactive polymerizable unsaturated group. That is, here, the organic component covering the surface of the silica particles refers to an organic component derived from an organic compound having a reactive polymerizable unsaturated group used for the surface treatment.

  The organic compound used for the surface treatment to coat the surface of the silica particles with an organic component is an organic compound having a polymerizable unsaturated group. The polymerizable unsaturated group is preferably at least two of hydroxy group, carboxy group, amino group, epoxy group, isocyanate group, (meth) acryloyl, and vinyl group, hydroxy group, carboxy group, and isocyanate group. Particularly preferred are any group and a (meth) acryloyl group.

  In the present invention, (meth) acrylate means methacrylate or acrylate.

  Further, specific examples of the organic compound having a polymerizable unsaturated group include, for example, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldiethoxysilane, and 3-methacryloxy. Coupling agents such as propyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane; methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, acrylic Acrylic acid esters such as butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, and phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate , Methacrylic acid esters such as ethoxymethyl methacrylate, phenyl methacrylate, lauryl methacrylate, 2- (N, N-diethylamino) ethyl acrylate, 2- (N, N-dimethylamino) ethyl methacrylate, acrylic 2-amino acid esters of unsaturated substituted acids such as 2- (N, N-dibenzylamino) methyl acrylate and 2- (N, N-diethylamino) propyl acrylate; unsaturated carboxylic acids such as acrylamide and methacrylamide Acid amides; ethylene glycol diacrylate, propylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6 hexanediol diacrylate, triethylene glycol diacrylate, etc .; dipropylene glycol Polyfunctional compounds such as diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, and diethylene glycol dimethacrylate; and / or polythiol compounds having two or more thiol groups in the branch (for example, trimethylolpropane trithioglycolate) , Trimethylolpropane trithiopropylate, pentaerythritol tetrathioglycol, etc.).

  By using reactive silica particles having a polymerizable unsaturated group in this way, the binder resin and the silica particles are cross-linked, and the silica particles are cross-linked, thereby improving the hardness and preventing the particles from falling off. It is done. In addition, chemical resistance can be improved by using modified silica particles.

The organic component covers almost the entire particle surface from the viewpoint of suppressing aggregation of the silica particles and improving the hardness of the hard coat layer by introducing many reactive functional groups to the surface of the silica particles. preferable. From such a viewpoint, the organic component covering the silica particles is preferably contained in the reactive silica particles at 1.00 × 10 ⁻³ g / m ² or more.

  The ratio of the organic component that is coated is usually a constant value of mass reduction when the dry powder is completely burned in air, for example, by thermal mass analysis from room temperature to usually 800 ° C. in air. Can be sought. The amount of organic compound per unit area can be determined by the following method. First, the value (organic component mass / inorganic component mass) obtained by dividing the organic component mass by the inorganic component mass is measured by differential thermal mass spectrometry (DTG). Next, the volume of the whole inorganic component is calculated from the mass of the inorganic component and the specific gravity of the silica used. Further, assuming that the silica particles before coating are spherical, the volume per silica before coating and the surface area are calculated from the average particle size of the silica particles before coating. Next, the number of reactive silica particles is determined by dividing the volume of the entire inorganic component by the volume per silica particle before coating. Furthermore, the amount of organic components per reactive silica particle is determined by dividing the mass of the organic component by the number of reactive silica particles. Finally, the amount of organic component per unit area can be determined by dividing the mass of the organic component per reactive silica particle by the surface area per silica particle before coating.

  As a method for preparing reactive silica particles having at least a part of the surface coated with an organic component and having a polymerizable unsaturated group introduced by the organic component on the surface, there is a polymerizable unsaturated group to be introduced into the silica particle. A conventionally known method can be appropriately used depending on the type of the above. Specifically, for example, reactive silica particles can be prepared by the method described in Examples described later.

  The reactive silica particles may be in the form of a powder that does not contain a dispersion medium. However, it is preferable to use particles in which fine particles are used as a solvent-dispersed sol because the dispersion step can be omitted and productivity is high.

  As a commercial item of the said reactive silica particle, Nissan Chemical Industries Ltd. make: MIBK-SD, MIBK-SDMS, MIBK-SDL, IPA-ST, IPA-SDMS etc. can be mentioned.

The average primary particle size can be measured by a laser diffraction / scattering method or the like. For example, it is possible to use a _{d 55} by using a particle size distribution meter Microtrac (manufactured by Nikkiso Co., Ltd.). When the silica particles are surface-modified, the particle size of the particles including the surface modification is the particle size in the present invention.

<Method for producing resin layer>
As the base film, the resin layer can be produced by any method, but it is easy to form a resin having a relatively large molecular weight, and it is easy to uniformly add the additive into the resin layer. It is preferable to form the resin layer by forming a film through a step of casting a solution containing a resin-containing resin on a substrate. That is, it is preferably produced by a solution casting method.

  Moreover, in order to use as a protective film for the anti-reflection use of an organic electroluminescent element, forming the said resin layer through the process which unwinds the film raw material wound up after the said film forming, and extends | stretches it diagonally. Is preferable.

  The resin layer includes 1) a step of preparing the dope solution by dissolving the above-described components in a solvent, 2) a step of casting the dope solution on an endless substrate, and 3) drying the cast dope and then peeling it off. And a film-like product (raw material) is obtained, and 4) a film-like product is dried and stretched.

  In the following description, a film having only a resin layer according to the present invention is also referred to as a resin film.

  Examples of the solvent used in the step 1) include, for example, 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, ethylene glycol monomethyl ether, dimethylformamide, dimethyl sulfoxide, dioxane, cyclohexanone, tetrahydrofuran, acetone, methyl ethyl ketone (MEK), ethyl acetate, diethyl ether; It is done.

  In the solution casting method, it is preferable that the concentration of the cycloolefin resin in the dope is higher because the drying load after casting on the substrate can be reduced. The load increases, and the filtration accuracy deteriorates. The concentration that makes these compatible is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass. The substrate 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.

  The width of the cast can be in the range of 1-4 m. The surface temperature of the substrate in the casting step is set from −50 ° C. to a temperature at which the solvent does not boil and foam. Higher temperatures are preferred because the web can be dried faster. Moreover, there is no concern that the web is foamed or the flatness is deteriorated within this temperature range.

  A preferable substrate temperature is appropriately determined within a range of 0 to 100 ° C, and more preferably within a range of 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 substrate is not particularly limited, and there are a method of blowing warm air or cold air, and a method of bringing hot water into contact with the back side of the substrate. It is preferable to use hot water because heat is efficiently transmitted, and the time until the temperature of the substrate 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 substrate and the temperature of the drying air during the period from casting to peeling.

  In order for the resin film to exhibit good flatness, the amount of residual solvent when peeling the web from the substrate is preferably in the range of 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. And particularly preferably within the range of 20 to 30% by mass or 70 to 120% by 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 resin film drying step, the web is peeled off from the substrate, and further dried, so that the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably. It is in the range of 0 to 0.01% by mass.

  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.

  In the stretching step, the stretching ratio in the maximum stretching direction (direction in which the stretching ratio becomes maximum) can be preferably in the range of 5 to 80%, more preferably 12 to 60%. For example, when extending | stretching to the biaxial direction orthogonal to each other, it can be set to 0 to 60% in a conveyance direction (MD direction) and 5 to 70% in a width direction (TD direction). The stretch ratio (%) is defined by the following formula.

Stretching rate (%) = {((stretching direction) length of stretched film− (stretching direction) length of stretched film) / (stretching direction) length of stretched film)} × 100
The stretching temperature can be in the range of 120 to 180 ° C, preferably 140 to 180 ° C, more preferably 145 to 165 ° C.

  From the viewpoint of suppressing an increase in haze, the residual solvent of the film-like product (also referred to as a film original fabric) at the start of stretching is preferably less than 5% by mass, more preferably 4% by mass or less, and further preferably 2% by mass. It can be as follows. In order to keep the residual solvent at the start of stretching at less than 5% by mass, it is preferable to provide the drying step in the process of peeling the cast dope from the substrate and transporting it to evaporate the solvent.

  The method of stretching the film-like material is not particularly limited, and a method of stretching a difference in peripheral speed between a plurality of rolls and using the difference in the peripheral speed of the roll between them in the MD direction; It may be a method of fixing with a clip or a pin and extending the gap between the clip or the pin in the TD direction. Among them, the stretching in the TD direction is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

  Moreover, the film raw film wound up after film forming can be unwound, and the resin layer can also be formed through the process of extending | stretching diagonally using the tenter which can be extended diagonally.

  An obliquely stretchable tenter is a device that widens a long original film in an oblique direction with respect to its traveling direction (moving direction of the middle point in the film width direction) in an oven heating environment. The tenter includes an oven, a pair of rails on the left and right on which a gripping tool for transporting the film travels, and a number of gripping tools that travel on the rails. Both ends of the film fed out from the film roll and sequentially supplied to the entrance portion of the tenter are gripped by a gripping tool, the film is guided into the oven, and the film is released from the gripping tool at the exit portion of the tenter. The film released from the gripping tool is wound around the core. Each of the pair of rails has an endless continuous track, and the gripping tool which has released the grip of the film at the exit portion of the tenter travels outside and is sequentially returned to the entrance portion.

FIG. 2 is an example of a tenter that can be stretched obliquely. As shown in FIG. 2 (A), the raw film 4 whose direction is controlled by the guide roll 12-1 on the drawing apparatus entrance side is an outer film holding start point 8-1 and an inner film holding start point. It is gripped by the gripping tool at the position 8-2.
The pair of left and right grippers are transported and stretched at an equal speed with each other in the oblique direction indicated by the outer film gripper track 7-1 and the inner film gripper track 7-2 by the oblique stretching device 6. The gripping is released by the film gripping end point 9-1 and the inner film gripping end point 9-2, and the conveyance is controlled by the guide roll 12-2 on the stretching device outlet side, whereby the obliquely stretched film 5 is formed. The same range as described above can be adopted for the heating temperature of the film during stretching, the traveling speed of the gripping tool, and the total stretching ratio. In the figure, the original film is stretched obliquely at an angle 14 (feeding angle θi) in the film stretching direction 14-2 with respect to the film feeding direction 14-1.

  In the obliquely stretched tenter used in the manufacturing method according to the embodiment of the present invention, especially in the inside of the tenter as shown in FIGS. A rate is required. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws an arc at the bent portion.

  In the oblique stretching tenter shown in FIG. 2A, the traveling direction 14-1 at the tenter entrance of the long film original is different from the traveling direction at the tenter exit side of the stretched film. The feeding angle θi is an angle formed between the traveling direction 14-1 at the tenter inlet and the stretching direction 14-2 of the stretched film.

  In the obliquely stretched tenter shown in FIG. 2B, the traveling direction 14-1 at the tenter entrance of the long film original is different from the traveling direction at the feeding angle θi in the tenter. Converted and transported. Thereafter, the transport direction is further changed, and finally, a trajectory that matches the traveling direction on the tenter exit side of the stretched film is taken. In the present invention, in order to produce a film having an orientation angle θ of preferably 10 to 80 ° as described above, the feeding angle θi is 10 ° <θi <60 °, preferably 15 ° <θi <50 °. Is set. By setting the feeding angle θi in the above range, the variation in the optical characteristics in the width direction of the obtained film becomes good (smaller).

  Other steps may be the same as those of a known solution casting method; for example, paragraphs 0109 to 0140 of JP2012-48214A.

<Method for producing optical film having hard coat layer>
The optical film having a hard coat layer is dried after 1) preparing the above-mentioned resin film and 2) applying a hard coat coating solution (active energy ray cured product coating solution) on the resin film. And a step of curing to obtain a hard coat layer which is an active energy ray cured product layer.

  The step of preparing the resin film of 1) is as described above. In the step 2), a coating solution prepared by using at least two solvents of alcohol, ester, ether or ketone as the solvent of the coating solution containing the ultraviolet curable resin and the silica particles may be applied. It is preferable in reducing drying unevenness.

  Examples of the solvent used in the step 2) include, for example, chlorinated solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene, and mixed solvents thereof; methanol, ethanol, isopropanol (IPA), n -Alcohol solvents such as butanol and 2-butanol; methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME), dimethylformamide, dimethyl sulfoxide, dioxane, cyclohexanone, tetrahydrofuran, acetone, methyl ethyl ketone (MEK) ), Ethyl acetate, diethyl ether; and the like.

  When casting a solution dissolved using at least two solvents of alcohol, ester, ether or ketone onto a substrate, one type is preferably a ketone, and among the ketones, methyl ethyl ketone (MEK) is preferred. It is preferable from the viewpoint of solubility of the UV curable resin. The other type is preferably an ether, and among the ethers, propylene glycol monomethyl ether (PGME) is preferable from the viewpoint of a high boiling point, slow drying, and unevenness suppressing effect.

  The application of the coating solution for the active energy ray cured layer of 2) can be performed by any means such as a dipping method, a die coater method, a wire bar method, and a spray method. Drying after coating can be performed by a known method.

Curing of the coating film of the coating solution for active energy ray cured layer of 2) can be performed by irradiating active energy rays. Examples of the light source that irradiates active energy rays (preferably ultraviolet rays) include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, and a xenon lamp. Irradiation light amount is sufficient if degree 20~10000mJ / cm ^2, preferably 50~2000mJ / cm ^2. The irradiation time is preferably 0.5 seconds to 5 minutes, and more preferably 3 seconds to 2 minutes from the viewpoint of work efficiency.

  The dry thickness of the hard coat layer is preferably in the range of 2 to 15 μm, more preferably in the range of 3 to 8 μm.

<Polarizer>
A polarizer is an element that passes only light having a plane of polarization in a certain direction, and a typical polarizer known at present is a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film includes those obtained by dyeing iodine on a polyvinyl alcohol film and those obtained by dyeing a dichroic dye.

  The polyvinyl alcohol polarizing film may be a film (preferably a film further subjected to durability treatment with a boron compound) dyed with iodine or a dichroic dye after uniaxially stretching the polyvinyl alcohol film; After the alcohol film is dyed with iodine or a dichroic dye, it may be a uniaxially stretched film (preferably a film further subjected to a durability treatment with a boron compound). The absorption axis of the polarizer is parallel to the stretching direction of the film.

  For example, the content of ethylene units described in JP-A-2003-248123, JP-A-2003-342322, etc. is 1 to 4 mol%, the degree of polymerization is 2000 to 4000, and the degree of saponification is 99.0 to 99.99 mol%. Ethylene-modified polyvinyl alcohol or the like is used. Among these, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C. is preferably used.

  The thickness of the polarizer is preferably 5 to 30 μm, and more preferably 10 to 20 μm in order to reduce the thickness of the polarizing plate.

<Polarizer>
In the present invention, the optical film of the present invention can be used as a protective film and can be used by being bonded to another base film through a polarizer, but the polarized light having a retardation film bonded through a polarizer. It is preferable to use it as a plate. Furthermore, it is also preferable to make a polarizing plate by giving a retardation to the optical film of the present invention and pasting it with a polarizer.

  The polarizing plate according to the present invention can be preferably applied to an organic EL display device and a liquid crystal display device. In the optical film of the present invention, the retardation value (Ro (550)) in the in-plane direction at a light wavelength of 550 nm preferably satisfies the following formula (1) in an environment of 23 ° C. and 55% RH.

Formula (1): 100 nm ≦ Ro (550) ≦ 170 nm
When Ro (550) satisfies the formula (1), the retardation film functions as a λ / 4 retardation film. By using a circularly polarizing plate in which the angle formed by the absorption axis of the polarizer and the slow axis of the λ / 4 retardation film is 45 °, a function of suppressing reflection of external light can be imparted. By using this for an organic electroluminescence display device, reflected light from the electrodes is prevented, and an excellent organic EL display device can be manufactured.

  Preferably, the in-plane retardation value Ro (550) measured at a wavelength of 550 nm is in the range of 120 to 160 nm, and Ro (550) is more preferably 130 to 150 nm.

  Moreover, when using for a liquid crystal display device, it is preferable to use the polarizing plate which used the optical film of this invention as a polarizing plate protective film, and bonded this with the other retardation film through the polarizer. The retardation of the retardation film depends on the type of the liquid crystal cell to be combined. For example, the retardation Ro (550) in the in-plane direction measured at a wavelength of 550 nm under the conditions of 23 ° C. and 55% RH is 20 to 100 nm. It is preferable that the retardation Rth (550) in the thickness direction is 70 to 300 nm. When the retardation is in the above range, it is suitable as a retardation film such as a VA liquid crystal cell.

  The retardation value Ro in the in-plane direction and the retardation value Rth in the thickness direction are defined by the following equations, respectively.

Formula _{(I): Ro = (n} x -n y) × d (nm)
Formula (II): Rth = {(n _x + n _y ) / 2−n _z } × d (nm)
(In the formulas (I) and (II),
n _x represents a refractive index in the slow axis direction x in which the refractive index is maximized in the plane direction of the film;
n _y represents a refractive index in a direction y orthogonal to the slow axis direction x in the in-plane direction of the film;
_nz represents the refractive index in the thickness direction z of the film;
d (nm) represents the thickness of the film)
The retardation values Ro and Rth can be obtained, for example, by the following method.

  1) Condition the optical film at 23 ° C. and 55% RH. The average refractive index of the optical film after humidity adjustment is measured with an Abbe refractometer or the like.

  2) Ro is measured with KOBRA-21DH, Oji Scientific Instruments Co., Ltd., when light having a measurement wavelength of 550 nm is incident on the optical film after humidity adjustment in parallel to the normal line of the film surface.

  3) With KOBRA-21ADH, the slow axis in the plane of the optical film is set as the tilt axis (rotation axis), and the measurement wavelength is 550 nm from the angle θ (incident angle (θ)) with respect to the normal of the film surface. The retardation value R (θ) when light is incident is measured. The retardation value R (θ) can be measured at 6 points every 10 ° in the range of 0 to 50 °. The in-plane slow axis refers to an axis having the maximum refractive index in the film plane, and can be confirmed by KOBRA-21ADH.

4) the measured Ro and R (theta), calculated from the average refractive index and film thickness of the above, the _KOBRA-21ADH, n x, calculates the _{n y} and _{n z,} and Rth at a measurement wavelength of 550nm To do. The retardation can be measured under conditions of 23 ° C. and 55% RH.

  The retardation value can be adjusted by changing the draw ratio.

  The polarizing plate can be obtained through a step of bonding the polarizer and the optical film of the present invention through an adhesive; and a step of cutting the bonded laminate into a predetermined size. The adhesive used for the bonding may be a completely saponified polyvinyl alcohol aqueous solution (water glue) or an active energy ray-curable adhesive. When water paste is used, it is preferable to corona-treat the cycloolefin film using a corona discharge treatment apparatus in order to improve the adhesiveness.

<Liquid crystal display device>
The liquid crystal display device includes a liquid crystal cell and a pair of polarizing plates that sandwich the liquid crystal cell.

  FIG. 3 is a schematic diagram illustrating an example of a basic configuration of the liquid crystal display device. As shown in FIG. 3, the liquid crystal display device 100 includes a liquid crystal cell 30, a first polarizing plate 50 and a second polarizing plate 70 that sandwich the liquid crystal cell 30, and a backlight 90.

  The display mode of the liquid crystal cell 30 may be various display modes such as STN, TN, OCB, HAN, VA (MVA, PVA), and IPS. For obtaining high contrast, the VA (MVA, PVA) mode is used. It is preferable that

  The first polarizing plate 50 includes a first polarizer 51, an optical film 53 (F 1) disposed on the surface opposite to the liquid crystal cell of the first polarizer 51, and the first polarizer 51. And an optical film 55 (F2) disposed on the surface on the liquid crystal cell side.

  The second polarizing plate 70 includes a second polarizer 71, an optical film 73 (F3) disposed on the surface of the second polarizer 71 on the liquid crystal cell side, and a liquid crystal cell of the second polarizer 71. Includes an optical film 75 (F4) disposed on the opposite surface. One of the optical films 55 (F2) and 73 (F3) may be omitted as necessary.

  And at least one of the optical films 53 (F1) and 75 (F4); preferably the optical film 53 (F1) may be the optical film of the present invention. The optical film 53 (F1) has a base film 53A and an active energy ray cured product layer 53B as a hard coat layer, and the base film 53A is in contact with the first polarizer 51. Since the liquid crystal display device in which the optical film 53 (F1) is the optical film of the present invention has high surface scratch resistance, the display screen can be hardly damaged.

《Organic electroluminescence display device》
An organic electroluminescence display device can include the optical film of the present invention.

  For the outline of the organic EL element applicable to the organic electroluminescence display device, for example, JP2013-157634A, JP2013-168552A, JP2013-177361A, JP2013-187221A. JP, 2013-191644, JP, 2013-191804, JP, 2013-225678, JP, 2013-235994, JP, 2013-243234, JP, 2013-243236, special JP 2013-242366, JP 2013-243371, JP 2013-245179, JP 2014-003249, JP 2014-003299, JP 2014-013910, JP 2014. -014933, Special It can be exemplified configuration described in 2014-017494 Patent Publication.

  The optical film of the present invention can be preferably used not only as a liquid crystal display device or an organic EL display device but also as a protective film for an image display device provided with a touch panel, an image display device such as a plasma display.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

樹脂（シクロオレフィン樹脂）
ＣＯＰ１：シクロオレフィン樹脂（ＡＲＴＯＮ Ｇ７８１０、ＪＳＲ（株）製）
ＣＯＰ２：シクロオレフィン樹脂（ＡＲＴＯＮ ＲＸ４５００、ＪＳＲ（株）製）
ＣＯＰ３：シクロオレフィン樹脂（ＡＲＴＯＮ Ｒ５０００、ＪＳＲ（株）製）
シリカ粒子
Ａ：下記製造例Ａで調製した反応性無機微粒子Ａ（平均一次粒径１３ｎｍのシリカ粒子）
Ｂ：下記製造例Ｂで調製した反応性無機微粒子Ｂ（平均一次粒径４６ｎｍのシリカ粒子）
Ｃ：下記製造例Ｃで調製した反応性無機微粒子Ｃ（平均一次粒径８７ｎｍのシリカ粒子）
Ｄ：平均粒径１２ｎｍのシリカ粒子（日産化学工業(株)製、スノーテックＮ）
〔シリカ粒子の調製〕
（反応性無機微粒子Ａの調製）
（１）表面吸着イオン除去
水分散コロイダルシリカ（日産化学工業(株)製、スノーテックＮ、平均粒径１２ｎｍ、ｐＨ９．０〜１０．０）を、陽イオン交換樹脂（三菱化学(株)製、ダイヤイオンＳＫ１Ｂ）５００ｇを用いて３時間イオン交換を行った。次に、陰イオン交換樹脂（三菱化学(株)製、ＳＡ２０Ａ）３００ｇを用いて３時間イオン交換を行った。その後、イオン交換水を用いて洗浄することで、固形分濃度２０質量％のシリカ微粒子水分散体を得た。Ｎａ２Ｏ含有量は、５ｐｐｍであった。 [Example 1]
The compounds used in the following examples are shown with their abbreviations.
Low molecular weight compound L1: 4-hydroxystyrene UV1: Tinuvin 928 (manufactured by BASF Japan Ltd.)
L3: Compound of n = 10 and m = 1 of PE1 below L4: Compound of n = 45 of PE2 below L5: Ethylene glycol L6: Copolymer ultraviolet absorber of methyl methacrylate / acryloyl morpholine (molar ratio 8/2) UV1: Tinuvin 928 (manufactured by BASF Japan Ltd.)
UV2: Tinuvin 109 (manufactured by BASF Japan Ltd.)
UV3: Tinuvin 171 (manufactured by BASF Japan Ltd.)
UV4: Tinuvin 405 (manufactured by BASF Japan Ltd.)
Compound having furanose structure or pyranose structure FP1: Sucrose benzoate FP2: Acetyl sucrose FP3: Sucrose diacetate (hexabutyrate)
Note that FP1 to FP3 are sugar esters obtained by esterifying all hydroxy groups.
Polyester compound

Resin (cycloolefin resin)
COP1: cycloolefin resin (ARTON G7810, manufactured by JSR Corporation)
COP2: cycloolefin resin (ARTON RX4500, manufactured by JSR Corporation)
COP3: cycloolefin resin (ARTON R5000, manufactured by JSR Corporation)
Silica particles A: Reactive inorganic fine particles A prepared in Production Example A below (silica particles having an average primary particle size of 13 nm)
B: Reactive inorganic fine particles B prepared in the following Production Example B (silica particles having an average primary particle size of 46 nm)
C: Reactive inorganic fine particles C prepared in the following Production Example C (silica particles having an average primary particle size of 87 nm)
D: Silica particles with an average particle size of 12 nm (Nissan Chemical Industry Co., Ltd., Snowtech N)
(Preparation of silica particles)
(Preparation of reactive inorganic fine particles A)
(1) Surface adsorbed ion removal Water-dispersed colloidal silica (manufactured by Nissan Chemical Industries, Ltd., Snowtech N, average particle size 12 nm, pH 9.0-10.0) was converted to cation exchange resin (manufactured by Mitsubishi Chemical Corporation). Ion exchange was performed using 500 g of Diaion SK1B) for 3 hours. Next, ion exchange was performed for 3 hours using 300 g of an anion exchange resin (SA20A, manufactured by Mitsubishi Chemical Corporation). Then, the silica fine particle water dispersion with a solid content concentration of 20 mass% was obtained by washing with ion exchange water. The Na2O content was 5 ppm.

(2) Surface treatment (introduction of monomer)
300 ml of isopropanol, 4.0 g of 3,6,9-trioxadecanoic acid, and 4.0 g of methacrylic acid are added to 20 g of the aqueous dispersion of inorganic fine particles subjected to the treatment of (1) above and stirred for 1 hour. did. The obtained mixed liquid was stirred while heating at 60 ° C. for 6 hours to obtain an inorganic fine particle dispersion in which methacryloyl groups were introduced into the inorganic fine particles. Distilled water, isopropanol and methacrylic acid are distilled off from the resulting inorganic fine particle dispersion using a rotary evaporator, methyl ethyl ketone is added so as not to dry, and the same amount as methacrylic acid used in the surface treatment (100%) Was added to obtain a silica-dispersed methyl ethyl ketone solution having a solid content of 50% by mass. Residual water and isopropanol were made 0.1 mass% or less. The obtained reactive inorganic fine particles A were measured with a particle size analyzer (Microtrac manufactured by Nikkiso Co., Ltd.), and the average primary particle size was d ₅₅ = 13 nm.

(Preparation of reactive inorganic fine particles B)
(1) Surface adsorbed ion removal Surface adsorbed in the same manner as in Production Example 1 using water-dispersed colloidal silica (Nissan Chemical Industry Co., Ltd., Snowtech OL, average primary particle size 44 nm, pH 2.0 to 4.0). An aqueous dispersion of inorganic fine particles from which ions were removed was obtained.

(2) Surface treatment (introduction of monomer)
In Production Example 1, methacrylic acid was changed to dipentaerythritol pentaacrylate (manufactured by Sartomer Co., Ltd., SR399), and surface treatment was performed in the same manner as in Production Example 1. Post-added dipentaerythritol pentaacrylate was 50%.

As a result of measuring the obtained reactive inorganic fine particle B with the particle size analyzer, the average primary particle size of d ₅₅ = 46 nm was obtained.

(Preparation of reactive inorganic fine particles C)
Water-dispersed colloidal silica (manufactured by Nissan Chemical Industries, Ltd., Snow Tech ZL, average particle size 85 nm, pH 9.0-10.0) was subjected to solvent substitution from water to methyl isobutyl ketone using a rotary evaporator to obtain silica fine particles 20 A mass% dispersion was obtained. 20 parts by mass of 3-methacryloxypropylmethyldimethoxysilane was added to 100 parts by mass of this methyl isobutyl ketone dispersion, followed by heat treatment at 50 ° C. for 1 hour. Methyl isobutyl ketone and 3-methacryloxypropylmethyldimethoxysilane are distilled off by using an evaporator, and methyl ethyl ketone is distilled off so as not to dry, so that a surface-treated methyl isobutyl ketone dispersion C having a solid content of 150% by mass is obtained. Obtained.

The obtained reactive inorganic fine particles C were measured by the particle size analyzer and found to have an average primary particle size of d ₅₅ = 87 nm.

[Hard coat layer coating solution]
(Preparation of hard coat layer coating solution 1 (HC1))
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 (A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd.) 60 parts by mass Surfactant (Surflon S-651, manufactured by AGC Seimi Chemical Co., Ltd.) 0.1 part by mass Silica particles A (40% methyl ethyl ketone dispersion) 100 parts by mass 40 parts by mass of propylene glycol monomethyl ether (PGME) << Preparation of optical film 1 >>
[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 was 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.

(Main dope)
COP1 100 parts by mass Dichloromethane 200 parts by mass Ethanol 10 parts by mass The above components were put into a sealed container and dissolved while stirring to prepare a main dope. Next, using an endless belt casting apparatus, the dope was uniformly cast on a stainless steel belt substrate 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 substrate, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 30%. Subsequently, it peeled from the stainless steel belt base | substrate with peeling tension 128N / m. The residual film at the start of stretching of the peeled film original was 5% by mass. Next, drying was completed while transporting the drying zone with a large number of rollers, the ends sandwiched between tenter clips were slit with a laser cutter, and then wound up to prepare a resin film 1 having a thickness of 30 μm.

  The hard coat layer coating solution 1 was applied to one side of the resin film 1 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 produce an optical film 1 in which a hard coat layer was formed on the resin film 1.

<< Preparation of optical film 2 >>
A resin film 2 and an optical film 2 were produced in the same manner as in the production of the optical film 1 except that the main dope was changed as follows in the production of the optical film 1.

(Main dope)
COP1 100 parts by mass Dichloromethane 200 parts by mass L1 5 parts by mass Ethanol 10 parts by mass The resin film 2 and the optical film 2 were produced in the same manner as in the production of the optical film 1.

<< Preparation of optical films 3-40 >>
In the production of the optical film 2, the type of cycloolefin resin (abbreviated as “resin” in Tables 1 and 2) contained in the main dope, the type and amount of additives, and silica particles in the hard coat layer and UV curing The ratio of the resin (UV resin), the type of silica particles, the solvent used in the hard coat layer coating solution, and the thickness of the hard coat layer were changed as shown in Tables 1 and 2, and the same as the production of the optical film 2 Resin films 3 to 40 and optical films 3 to 40 were produced. The solvent used for the hard coat layer coating solution was prepared to be 100 parts by mass.

<< Evaluation of optical film >>
The produced optical films 1 to 40 were evaluated for pencil hardness, scratch resistance, haze, and drying unevenness.

<Pencil hardness>
It was carried out according to the standard of JIS K 5600 (scratch hardness (pencil method)). A scratch test was performed on the surface of each hard coat film sample with a pencil of 45 degrees and a load of 750 g. If it is “H” or more, it can be put to practical use.

<Scratch resistance>
The scratch resistance was evaluated by conducting a rubbing test under the following conditions. The surface of the hard coat layer in an environment of 23 ° C. and 55% RH was reciprocated 10 times with steel wool applied with a load of 500 g / cm ² (# 0000, manufactured by Nippon Steel Wool Co., Ltd.), and the presence or absence of scratches was visually observed. The following ranking was performed and evaluated. O If it is more than, it can use for practical use.
◎: Less than 1 scratch ○: 2 or more and less than 4 scratches △: 5 or more and less than 8 scratches ×: 8 or more scratches <Haze>
It carried out according to JIS K 7165. Samples were measured with a haze meter (trade name NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) using a D65 light source, and the following ranking was performed for evaluation. O If it is more than, it can use for practical use.
A: Less than 0.2% B: 0.2% or more and less than 0.5% Δ: 0.5% or more and less than 1.0% x: 1.0% or more <Drying unevenness>
The surface of the optical film was observed and unevenness was evaluated as follows. A black PET film with an adhesive was attached to the back surface of the optical film and evaluated by visual evaluation under a fluorescent lamp. The results were ranked and evaluated as follows.
A: Unevenness is not seen even when viewed carefully. O: Unevenness is partially recognized when carefully viewed. Δ: There is weak unevenness. X: Unevenness is observed Tables 1 and 2 show the above results.

  In the table, IPA represents isopropanol and ethyl acetate represents ethyl acetate. The column of molecular weight represents the weight average molecular weight of the low molecular weight compound, and when the low molecular weight compound is not a polymer, the molecular weight of the compound is described.

  Tables 1 and 2 show that the optical film of the present invention has high surface hardness, excellent scratch resistance, and low haze. Moreover, when a hard-coat layer is formed through the process of apply | coating the coating liquid prepared using 2 types of solvents, it turns out that drying unevenness is good.

[Example 2]
<< Production of Optical Film 101 >>
In production of the optical film film 12, after peeling off the film original fabric, the peeled film original fabric was uniaxially stretched 40% in the width direction at 160 ° C. Otherwise, the resin film 101 and the optical film 101 were produced in the same manner as the production of the polarizing plate protective film 12.

<< Production of Optical Film 102 >>
In the production of the optical film 12, after peeling the film original fabric, the peeled film original fabric is stretched at a temperature of 160 ° C. using the tenter shown in FIG. The film was obliquely stretched 60% in the direction of the degree. Otherwise, the resin film 102 and the optical film 102 were produced in the same manner as the production of the polarizing plate protective film 11.

<< Evaluation of optical films 12, 101, 102 >>
(Measurement of retardation)
About the produced optical films 101 and 102 and the optical film 12 produced in Example 1, using an ellipsometer (M-150, manufactured by JASCO Corporation), the retardation value Ro in the in-plane direction at a wavelength of 550 nm, respectively. The retardation value Rth in the thickness direction was measured. Each measurement was performed at 10 points in the width direction, and an average value was obtained.

Also, the optical films 101, 102, and 12 produced in the same manner as in Example 1 were evaluated for pencil hardness, scratch resistance, haze, and drying unevenness using the same method and the same evaluation criteria as in Example 1. .
The results are shown in Table 3.

  From Table 3, it can be seen that the optical film of the present invention has high surface hardness, excellent scratch resistance, and low haze. Moreover, it turns out that the optical films 101 and 102 are useful for a liquid crystal display device and an organic EL display device as a retardation film.

DESCRIPTION OF SYMBOLS 1 Optical film 2 Resin layer 3 Hard coat layer 4 Long film original fabric 5 Stretched film 6 Diagonal stretch tenter 7-1 Trajectory of outer film gripping means 7-2 Trajectory of inner film gripping means 8-1 Outer film gripping Start point 8-2 Inner film grip start point 9-1 Outer film grip end point 9-2 Inner film grip end point 10-1 Outer oblique stretching start point 10-2 Inner oblique stretching start point 11-1 Outer oblique Stretching end point 11-2 Inner diagonal stretching end point 11-3 Outer lateral stretching zone end point 12-1 Guide roll on the tenter inlet side 12-2 Guide roll on the tenter outlet side 13 Film stretching direction 14-1 Film before diagonal stretching 14-2 Conveying direction of film after oblique stretching 15 Portion where conveyance speeds of left and right gripping tools are different W0 Before oblique stretching Irumu the width length W film width hands after oblique stretching length 30 liquid crystal cell 50 first polarizer 51 first polarizer 53 protective film (F1)
55 Protective film (F2)
70 Second polarizing plate 71 Second polarizer 73 Protective film (F3)
75 Protective film (F4)
90 Backlight 100 Liquid crystal display device

Claims (9)

  An optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer is a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. On the other hand, the optical film is contained within a range of 0.1 to 5.0% by mass, and the hard coat layer contains an ultraviolet curable resin and silica particles.   The optical film according to claim 1, wherein the low molecular weight compound contained in the resin layer is an ultraviolet absorber.   The mass ratio value of the silica particles to the ultraviolet curable resin (silica particles / ultraviolet curable resin) contained in the hard coat layer is in the range of 10/90 to 50/50. Item 3. The optical film according to Item 1 or Item 2.   The average primary particle diameter of the silica particles is 200 nm or less, and the optical film according to any one of claims 1 to 3.   The thickness of the said hard-coat layer exists in the range of 2-15 micrometers, The optical film as described in any one of Claim 1- Claim 4 characterized by the above-mentioned. The retardation value (Ro (550)) in the in-plane direction at an optical wavelength of 550 nm in an environment of 23 ° C. and 55% RH satisfies the following formula (1): The optical film as described in any one.
Formula (1): 100 nm ≦ Ro (550) ≦ 170 nm   A production method for producing an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer contains a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. It contains in the range of 0.1-5.0 mass% with respect to cycloolefin type resin, the said hard-coat layer contains a ultraviolet curable resin and a silica particle, and the said ultraviolet curable resin and the said silica particle are included. Production of an optical film characterized by forming a hard coat layer through a step of applying a coating solution prepared using at least two solvents of alcohol, ester, ether or ketone as a solvent for the coating solution to be contained Method.   A production method for producing an optical film having a hard coat layer on a resin layer containing a cycloolefin resin, wherein the resin layer contains a low molecular weight compound having a weight average molecular weight Mw in the range of 100 to 10,000. Resin which contains in the range of 0.1-5.0 mass% with respect to cycloolefin type resin, the said hard-coat layer contains ultraviolet curing resin and a silica particle, and contains the said cycloolefin type resin A method for producing an optical film, wherein the resin layer is formed by casting a solution in which the solution is dissolved on a substrate to form a film.   The method for producing an optical film according to claim 8, wherein the resin layer is formed through a step of unwinding the original film wound after the film formation and stretching the film in an oblique direction.

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