KR20070106442A - Method for making optical film, optical film, and method for making stretched film - Google Patents

Abstract

A method for producing an optical film is provided to obtain a cyclic olefin-based optical film having an optional phase difference, high optical uniformity and a large length, and to obtain a high-quality disk for an oriented film useful for producing LCD devices. A method for producing an optical film comprises the steps of: extruding a molten cyclic olefin resin from a die; compressing the extruded resin against a substrate to provide a film; removing the film from the substrate; and winding the film in the shape of a roll, wherein a stress of 1-30 kgf/cm^2 is applied at a temperature ranging from Tg(glass transition temperature of the cyclic olefin resin) - 30 deg.C to Tg + 20 deg.C during any one step from the step of removing the film to the step of winding the film in the shape of a roll.

Description

Method for Making Optical Film, Method for Making Optical Film, and Stretched Film {Method For Making Optical Film, Optical Film, and Method For Making Stretched Film}

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2005-254812

[Patent Document 2] Japanese Patent Application Laid-Open No. 1-240517

This invention relates to the manufacturing method of the optical film from which the optical film which has arbitrary phase difference is obtained by a simple method, the optical film suitable as a raw film of a stretched film, and the manufacturing method of the stretched film using the said optical film.

Since cyclic olefin is excellent in transparency, heat resistance, moisture resistance, etc., it is used preferably for the use of an optical film. Usually, the film containing cyclic olefin resin is formed into a film by the solution casting method (solution casting method), the melt-extrusion method, etc., and is produced by extending | stretching etc. as needed.

The optical film is required to be excellent in optical properties such as transparency, and at the same time, it is important that the film is homogeneous and the optical nonuniformity is small. As optical nonuniformity which arises at the time of manufacture of an optical film, the retardation nonuniformity which arises at the time of extending | stretching is mentioned. Examples of the stretching method without phase difference unevenness include a method of adjusting clip intervals and temperature conditions in the tenter stretching method, but a method for producing a film with less optical nonuniformity is required by a simpler method.

The present invention provides a method for producing a cyclic olefin optical film having an arbitrary retardation, a small optical nonuniformity, and a long length by a simple method, an optical film useful as a raw material of the stretched film, and a method of producing a stretched film using the optical film. It is a subject to offer.

The method for producing an optical film of the present invention (hereinafter also referred to as "manufacturing method 1") is obtained by extruding a molten cyclic olefin resin from a die, compressing the film to a substrate, and peeling the film from the substrate to take up a roll. In the manufacturing process of an optical film, in any one process until peeling a film from a base material and winding up in roll shape, it is 1-30 kgf / cm <2> of the said cyclic olefin resin at the temperature of Tg-30 degreeC-Tg + 20 degreeC. It is characterized by having a step of applying a stress (wherein, Tg represents the glass transition temperature. The same applies hereinafter).

In the manufacturing method 1, when peeling a film from a base material, it is preferable to peel from a base material with a stress of 1-30 kgf / cm <2> under the temperature of Tg-30 degreeC-Tg + 20 degreeC of cyclic olefin resin.

The method for producing the optical film of the present invention (hereinafter also referred to as "manufacturing method 2") is soluble on a substrate by dissolving or dispersing a cyclic olefin resin in an organic solvent, and removing a part of the organic solvent to form a film composition. In the manufacturing process of the optical film which peels a film composition from the said base material, and removes an organic solvent further and winds up in roll shape, in any one process until peeling a film composition from a base material and winding up in a roll shape. WHEREIN: It has a process of applying the stress of 1-30 kgf / cm <2> at the temperature of the apparent Tg-30 degreeC-Tg + 20 degreeC of the said film composition (However, the apparent Tg of a film composition is a said film composition. The Tg measured by the DSC curve measured on the conditions of temperature rising of 20 degree-C / min.

In the manufacturing method 2, when peeling a film composition from a base material, it is preferable to peel from a base material with a stress of 1-30 kgf / cm <2> under the temperature of apparent Tg-30 degreeC-Tg + 20 degreeC of the said film composition.

The optical film of this invention contains cyclic olefin resin, nx the refractive index of the direction which shows the largest refractive index in the film plane at the light wavelength of 550 nm, ny the refractive index of the direction orthogonal to nx in a film plane, and When d [nm], phase difference R0 (550) [nm] = (nx-ny) xd in the film plane is 20 nm or more and 300 nm or less, while the variation in R0 is within ± 10%, while the maximum refractive index in the film plane is It is characterized in that the maximum value of the angle formed by the direction and the film longitudinal direction to represent 0 ° to 10 °.

As cyclic olefin resin, resin obtained by superposing | polymerizing or copolymerizing 1 or more types of compounds represented by following General formula (1) is preferable.

In formula, R <^1> -R <^4> is a hydrogen atom, a halogen atom, a C1-C30 hydrocarbon group, or other monovalent organic group, respectively, may be same or different, and also any 2 of R <^1> -R <^4> . The dogs may combine with each other to form a monocyclic or polycyclic structure, m is zero or a positive integer, and p is zero or a positive integer.

The manufacturing method of the stretched film of this invention is characterized by extending | stretching the optical film of this invention to a film width direction or a film longitudinal direction.

The manufacturing method of the stretched film of this invention is characterized by extending | stretching the obtained optical film to a film width direction following manufacture method 1 or 2.

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

Cyclic olefin resin

The optical film which concerns on this invention contains cyclic olefin resin. As cyclic olefin resin, addition (co) using the cyclic olefin compound which has the norbornene frame | skeleton represented by the said Formula (1) alone or in combination of 2 or more types, or copolymerization monomers other than a cyclic olefin type compound as a polymerization or copolymerization monomer Polymers, ring-opening (co) polymers, or (co) polymers obtained by hydrogenating a double bond in the main chain after ring-opening (co) polymerization are all used.

As cyclic olefin resin which comprises the optical film which concerns on this invention, it is preferable to use the (co) polymer obtained from the monomer represented by the said Formula (1) (Hereinafter, it is also called a "specific monomer."). Specifically, (a) The polymer or copolymer shown to (e) (henceforth an "(co) polymer") can be used preferably.

(a) ring-opening polymers of certain monomers (hereinafter also referred to as "specific ring-opening polymers")

(b) ring-opening copolymers of specific monomers and cyclic monomers copolymerizable therewith (excluding specific monomers, hereinafter also referred to as "copolymerizable cyclic monomers") (hereinafter also referred to as "specific ring-opening copolymers")

(c) saturated copolymers of specific monomers and unsaturated double bond-containing compounds (hereinafter also referred to as "specific saturated copolymers")

(d) hydrogenated (co) polymers of certain ring-opening polymers or of certain ring-opening copolymers (hereinafter also referred to as "specific ring-opening (co) polymers")

(e) Hydrogenated (co) polymer obtained by cyclizing a specific ring-opening (co) polymer by Friedel Craft reaction and then hydrogenating

Among them, the hydrogenated (co) polymer of (d) or (e) is preferably used because it has higher transparency, and more preferably has a structural unit represented by the following general formula (1a) corresponding to (d) ( Co) polymers, and particularly preferably (co) polymers having a structural unit represented by the following formula (2).

In the formula, the definitions of R ¹ to R ⁴ , p, m are the same as in the general formula (1).

In formula, the definition of R <^1> -R <^4> is the same as that of the said General formula (1).

[Specific monomer]

As a preferable specific monomer, in said Formula (1), R <^1> and R <^3> is a hydrogen atom or a C1-C10 hydrocarbon group, R <^2> and R <^4> is a hydrogen atom or a monovalent organic group, R <^2> and R <^4> At least one represents a polar group 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, and a value of m + p is 0 to 4, more preferably 0 to 2, particularly Preferably, 1 is mentioned.

Moreover, the specific monomer in which R <^2> and R <^4> has a polar group represented by following formula (3) has a high glass transition temperature (henceforth "Tg"), and the low hygroscopic cyclic olefin thermoplastic resin is obtained. Preferred at

-(CH ₂ ) _n COOR ⁵

In formula, R <^5> represents a C1-C12 hydrocarbon group and n is an integer of 0-5.

In Formula 3, R ⁵ is preferably an alkyl group. Moreover, since the value of n is small, since Tg of cyclic olefin resin obtained becomes high, it is preferable, and especially the specific monomer which n is 0 is preferable at the point which the synthesis | combination is easy.

In Formula 1, R ¹ or R ³ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably an alkyl group having 1 to 2 carbon atoms, and particularly preferably a methyl group. . Moreover, it is preferable that this alkyl group is couple | bonded with the same carbon atom as the carbon atom which the polar group represented by the said Formula (3) couple | bonded.

Moreover, in the said General formula (1), the specific monomer whose m is 1 is preferable at the point from which the thermoplastic resin composition with a higher Tg is obtained.

As a specific example of the specific monomer represented by the said General formula (1),

Bicyclo [2.2.1] hept-2-ene,

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Dimethanooctahydronaphthalene,

Ethyl tetracyclododecene,

6-ethylidene-2-tetracyclododecene,

Trimetaoctaoctahydronaphthalene,

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

Heptacyclo [8.4.0.1 ^3,6 .1 ^10,17 .1 ^12,15 .0 ^2,7 .1 ^11,16 ] -4-eicosene,

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

(Ethoxycarbonyl 2,2,2-trifluoroethyl) 8-methyl-8 and the like can be mentioned tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3- dodecene.

Among these specific monomers, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene, 8-ethylidene tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene, pentacyclo [7.4.0.1 ^2,5 .1 ^9,12 . 0 ^8,13 ] -3- ^pentadecene is preferable at the point from which the cyclic olefin resin which has the outstanding heat resistance is obtained.

[Copolymerizable Cyclic Monomer]

As a copolymerizable cyclic monomer for obtaining a specific ring-opening copolymer, it is preferable to use a cycloolefin having 4 to 20 carbon atoms, particularly 5 to 12 carbon atoms. Specific examples thereof include cyclobutene, cyclopentene, cycloheptene, cyclooctene and tricyclo [ 5.2.1.0 ^2,6 ] -3-decene, 5-ethylidene-2-norbornene, dicyclopentadiene, etc. are mentioned.

[Unsaturated double bond containing compound]

The unsaturated double bond-containing compound for obtaining a specific saturated copolymer includes a carbon-carbon double bond in the main chain such as polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-nonconjugated diene copolymer, and polynorbornene. Unsaturated hydrocarbon polymers can be used.

The use ratio of the specific monomer and the copolymerizable cyclic monomer or the unsaturated double bond-containing compound is preferably 100: 0 to 50:50 by weight of the specific monomer: copolymerizable cyclic monomer or the unsaturated double bond-containing compound, more preferably 100 : 0 to 60:40.

When the use ratio of a copolymerizable cyclic monomer or an unsaturated double bond containing compound is excessive, since Tg of the copolymer obtained falls and as a result, the heat resistance of resin falls, it becomes difficult to obtain a film with high heat resistance.

[Opening polymerization catalyst]

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

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

Specific examples of the compound constituting the component _{(b), nC 4 H 9 Li, (} C 2 H 5) 3 Al, (C 2 H 5) 2 AlCl, (C 2 H 5) 1.5 AlCl 1 .5, ( C ₂ H ₅₎ AlCl _2, there may be mentioned compounds described in Japanese Unexamined Patent Publication (Kokai) No. 1-240517 Publication, such as methyl alumoxane, LiH.

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

[Hydrogenation]

As cyclic olefin resin used for this invention, in addition to the said specific ring-opening (co) polymer and a specific saturated copolymer, the hydrogenated (co) polymer obtained by hydrogenating to a specific ring-opening (co) polymer, and the specific ring-opening (co) polymer After cyclization by Friedel Craft reaction, the hydrogenated (co) polymer obtained by hydrogenation can be used here.

Since these hydrogenated (co) polymers have excellent thermal stability, it is possible to prevent their properties from deteriorating by heating when performing molding processing or when using them as products.

The hydrogenation rate in a hydrogenated (co) polymer here is 50% or more normally, Preferably it is 70% or more, More preferably, it is 90% or more, More preferably, it is 95% or more, Especially preferably, it is 97% or more.

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

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

Moreover, it is preferable that the Vicat softening point of cyclic olefin resin is 110 degreeC or more.

Moreover, the cyclic olefin resin film used by this invention can be formed from the resin composition containing cyclic olefin resin as mentioned above. In addition to cyclic olefin resin, the resin composition can mix | blend the various additives which can be mix | blended with resin, such as resin components other than cyclic olefin resin, a stabilizer, a workability improving agent.

Manufacturing method of optical film

The optical film according to the present invention is a film obtained by forming the above-mentioned cyclic olefin resin into a film, and is a film obtained by winding a film having a length of 50 m or more in a lengthwise direction, preferably in a lengthwise direction. In the form of a roll.

Although it does not specifically limit as a method of forming a cyclic olefin resin into a film form, Melt-molding methods, such as the melt-extrusion method, or the solution casting method (solvent casting method) are mentioned preferably. In any case, in the process up to winding the film into a roll shape, the film (film composition comprising a cyclic olefin resin itself in the case of the melt extrusion method and a cyclic olefin resin and an organic solvent in the case of the solution casting method) It has a process of applying a stress of 1-30 kgf / cm <2> under the temperature of Tg-30 degreeC-Tg + 20 degreeC. By having the said process, the angle which the retardation in the film surface in the light wavelength of 550 nm is 20 nm or more and 300 nm or less, and the direction which shows the maximum refractive index in a film surface and the film length direction, while the variation of R0 is within ± 10%. It becomes possible to easily obtain the optical film with little optical nonuniformity whose maximum value of is 0 degrees-10 degrees.

Melt Extrusion Method

It does not specifically limit as a melt-extrusion method, For example, the cyclic olefin resin which is shaping | molding resin material is melt | dissolved using the well-known single-screw extruder or twin screw extruder as a melt extruder (Hereinafter, , Which is also referred to as "melt resin", can be quantitatively measured by a gear pump, and a method of extrusion into a film form from a die having a slit outlet can be used.

Moreover, it is preferable that the extruder is equipped with the polymer filter for removing the foreign material in the molding resin material quantified by the gear pump, and the contaminants, such as the soot and gel produced during melt-extruding process.

It is preferable that L / D is 28-40 here as an extruder, and although the screw diameter changes with extrusion amount, it is 30-125 mm normally. If the screw diameter is less than 30 mm, the metering stability and film productivity may be lowered. On the other hand, if the screw diameter is larger than 125 mm, the measured molten resin may stay, which may cause thermal deterioration.

As a gear pump, since a molten resin can be discharged smoothly, an external lubrication type is used preferably. As the die, a T die is usually used. A coat hanger die, a fish tail die, etc. are mentioned as T die, Among these, a coat hanger die is preferable. Moreover, there is no restriction | limiting in particular as a manifold, The thing which has a structure in which retention does not occur easily is used from a viewpoint of suppressing the thermal deterioration of molded resin material.

As a polymer filter, the leaf disc type thing is used preferably from the point which can suppress that molten resin stays. In addition, the filtration precision of a polymer filter is 20 micrometers or less normally, Preferably it is 10 micrometers or less. When filtration precision exceeds 20 micrometers, a contaminant will pass through a polymer filter, and there exists a possibility that a defective appearance, such as a black defect, may arise in the specific laminated body obtained.

The film-like resin extruded from the die is usually filmed by cooling the pressing onto the substrate. As a base material, the roll-type base material which surface-coated the metal roll or belt type base material, and ceramics, such as aluminum oxide and chromium oxide, is used preferably. Examples of the film forming method include a nip roll method, an electrostatic application method, an air knife method, a calendar method, a single belt method, a double-sided belt method, a three roll method, and the like. An open roll system or a single sided belt type is preferably used. In single-sided belt type, the film manufacturing apparatus called a sleeve type is especially used preferably. For example, the film manufacturing apparatus in which the mirror surface roll and a metal belt are arrange | positioned under the discharge port of a die | dye, and the peeling roll is arrange | positioned so that it may be arranged in parallel with the said mirror surface roll is mentioned. The metal belt is held in a tensioned state by two retaining rolls provided to contact the inner surface thereof. The resin discharged from the discharge port is pinched by passing between the mirror surface roll and the metal belt, transferred to the mirror surface roll, cooled, and then peeled by a peeling roll to form a film.

In the manufacturing method 1 of this invention, in any one process from peeling a film from a base material by the melt-extrusion method to winding up in roll shape, it is 1-30 kgf / under the temperature of Tg-30 degreeC-Tg + 20 degreeC of cyclic olefin resin. It is characterized by having a process of applying a stress of cm 2. Preferably, when peeling a film from a base material, it peels from a base material with a stress of 1-30 kgf / cm <2> under the temperature of Tg-30 degreeC-Tg + 20 degreeC of cyclic olefin resin. The temperature condition is preferably Tg-20 占 폚 to Tg + 10 占 폚, more preferably Tg-10 占 폚 to Tg + 5 占 폚, and the stress is preferably 5 to 30 kgf / cm2, more preferably 10 to 20 kgf / cm2. to be.

[Solution softening method]

As the solution casting method (solvent casting method), for example, a cyclic olefin resin is dissolved or dispersed in an organic solvent to form a liquid having a suitable concentration, poured or applied onto a suitable substrate (carrier), and dried from the substrate. The method of peeling is mentioned.

When dissolving or dispersing cyclic olefin resin in a solvent, the concentration of the resin is usually 0.1 to 90% by weight, preferably 1 to 50% by weight, more preferably 10 to 35% by weight. When the density | concentration of the said resin is less than the said range, it becomes difficult to ensure the thickness of a film. In addition, problems such as difficulty in obtaining surface smoothness of the film due to foaming due to evaporation of the solvent occur. On the other hand, when the concentration exceeds the above range, the solution viscosity becomes too high, so that the thickness and the surface of the optical film obtained become difficult to be uniform.

In addition, the viscosity of the solution at room temperature is usually 1 to 1,000,000 (mPa · s), preferably 10 to 100,000 (mPa · s), more preferably 100 to 100,000 (mPa · s), particularly preferably Is 1,000 to 10,000 (mPa · s).

Examples of the solvent used herein include aromatic solvents such as benzene, toluene, and xylene, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and 1-methoxy-2-propanol, diacetone alcohol, acetone, and cyclohexa. Ketone solvents such as rice paddy, methyl ethyl ketone, 4-methyl-2-pentanone, cyclohexanone, ethylcyclohexanone and 1,2-dimethylcyclohexane, ester solvents such as methyl lactate and ethyl lactate, 2, Halogen-containing solvents such as 2,3,3-tetrafluoro-1-propanol, methylene chloride and chloroform, ether solvents such as tetrahydrofuran and dioxane, alcohols such as 1-pentanol and 1-butanol And solvents.

Further, in addition to the SP value (solubility parameter) is typically 10 to 30 (MPa ^1/2), preferably from 10 to 25 (MPa ^1/2), more preferably from 15 to 25 (MPa ^1/2), in particular, preferably, when using a solvent of 15 to 20 (MPa ^1/2) range, surface uniformity and optical characteristics can be obtained a good film.

The said solvent can be used individually or in combination of 2 or more types. When using 2 or more types of solvents together, SP value as a mixture can be calculated | required from the weight ratio, For example, in the case of 2 types of mixtures, the weight fraction of each solvent makes W1, W2, and SP values SP1 and SP2. The SP value of a mixed solvent can be calculated | required as the value computed by following formula (1).

SP value = W1, SP1 + W2, SP2

In the preparation of the cyclic olefin resin solution, the temperature in the case of dissolving the cyclic olefin resin in a solvent may be room temperature or high temperature. A uniform solution is obtained by stirring sufficiently. On the other hand, when coloring as needed, you may add suitably the coloring agent of dye and a pigment to a solution.

In addition, a leveling agent may be added to improve the surface smoothness of the film. As long as it is a general leveling agent, all can be used, For example, a fluorine-type nonionic surfactant, a special acrylic resin leveling agent, a silicone leveling agent, etc. can be used.

As a method for producing the film used in the present invention by the solution casting method, a belt such as a metal drum (cast drum), a steel belt, a belt made of polytetrafluoroethylene, a polyethylene terephthalate ( The method of apply | coating on base materials, such as polyester films (base films), such as PET) and polyethylene naphthalate (PEN), drying and removing a solvent after that, and generally peeling off from a base material is mentioned. In the present invention, it is preferable that the film-like composition containing the resin and the solvent is peeled from the substrate, further dried to remove the solvent, and the optical film is removed without removing all of the solvent before peeling from the substrate. It is preferable that the said film-form composition peels from a base material in the state containing 5-30 weight% of solvents, Preferably 5-20 weight%. Moreover, it can also manufacture by apply | coating a resin solution to a base material using means, such as spraying, a brush, roll spin coating, and immersion, drying and removing a solvent and peeling from a base material after that. On the other hand, thickness, surface smoothness, etc. can be controlled by repetition of application | coating.

In addition, when using base films, such as a polyester film, as a base material, the surface-treated film can be used. As a surface treatment method, the hydrophilization treatment method currently performed, for example, the method of laminating | stacking acrylic resin and sulfonic acid base containing resin with a coating or a laminate, or the method of improving the hydrophilicity of a film surface by corona discharge treatment etc. are mentioned. Can be. In the present invention, a cast drum, a belt or a base film is preferably used as the substrate.

There is no restriction | limiting in particular about the drying (solvent removal) process of the film-form composition after peeling on a base material or a base material, It can carry out by the method generally used, for example, the method of passing through an inside of a drying furnace through many rollers. However, when bubbles are generated due to evaporation of the solvent in the drying step, the properties of the film are significantly reduced. Therefore, in order to avoid this, it is preferable to use the drying step in two or more steps, and to control the temperature or air volume in each step. .

The amount of residual solvent in the finally obtained optical film is 10 weight% or less normally, Preferably it is 5 weight% or less, More preferably, it is 1 weight% or less, Especially preferably, it is 0.5 weight% or less. Here, when the amount of residual solvent is more than 10 weight%, when the said film is actually used, the dimensional change with time becomes large and it is unpreferable. Moreover, since Tg becomes low and heat resistance also falls by residual solvent, it is unpreferable. On the other hand, the film peeled and dried from a base material is usually wound up in roll shape.

On the other hand, in order to perform the extending process mentioned later preferably, it is necessary to adjust the said residual solvent amount suitably within the said range. Specifically, the amount of residual solvent is usually 10 to 0.1% by weight, preferably 5 to 0.1% by weight, more preferably 1 to 0.1% by weight in order to stably and uniformly express the phase difference in the stretching orientation. Can be. By remaining a trace amount of the solvent, the stretching processing may be easy or the control of the phase difference may be easy.

In the manufacturing method 2 of this invention, a cyclic olefin resin is melt | dissolved or disperse | distributed in an organic solvent, it is cast on a base material, a part of said organic solvent is removed, it is set as a film composition, the film composition is peeled off from the said base material, and further In the manufacturing process of the optical film which removes an organic solvent and winds up in roll shape, in any process until peeling a film composition from a base material and winding up in roll shape, it is apparent Tg-30 degreeC-Tg + 20 of the said film composition. It is characterized by having a step of applying a stress of 1 to 30 kgf / cm 2 at a temperature of ℃. The apparent Tg of the film-like composition here is Tg measured by the DSC curve which measured the said film-like composition on the temperature rising condition of 20 degree-C / min, specifically, the temperature in the polarization point of the DSC curve measured by the said conditions Say. On the other hand, in the manufacturing method 2, when peeling a film composition from a base material preferably, it peels from a base material with a stress of 1-30 kgf / cm <2> under the temperature of apparent Tg-30 degreeC-Tg + 20 degreeC of a film form composition. The temperature condition is preferably Tg-20 占 폚 to Tg + 10 占 폚, more preferably Tg-10 占 폚 to Tg + 5 占 폚, and the stress is preferably 5 to 30 kgf / cm2, more preferably 10 to 20 kgf / cm2. to be.

Optical film

The optical film of this invention contains the above-mentioned cyclic olefin resin, nx, and the refractive index of the direction orthogonal to nx in a film surface ny, the refractive index of the direction which shows the largest refractive index in the film surface at a light wavelength of 550 nm, When the thickness is d [nm], the phase difference R0 (550) [nm] = (nx-ny) xd in the film plane is 20 nm or more and 270 nm or less, while the variation in R0 is within ± 10%. The maximum value of the angle between the direction indicating the maximum refractive index and the film length direction (hereinafter also referred to as "θ ₁ ") is 0 ° to 10 °.

The phase difference R0 (550) in the film plane at the light wavelength of 550 nm is 20 nm or more and 300 nm or less, Preferably it is 50 nm or more and 280 nm or less, Especially preferably, it is 100 nm or more and 280 nm or less. If the retardation in the film plane is less than 20 nm, the characteristics as the retardation film are insufficient, and if it exceeds 300 nm, there is a problem that performance cannot be exhibited when the retardation film is used. In addition, the variation in R0 is within ± 10%, preferably within ± 5%, particularly preferably within ± 3%.

Further, θ ₁ is 0 ° to 10 °, preferably 0 ° to 5 °, particularly preferably 0 ° to 1 °. When (theta) ₁ exceeds 10 degrees, when the said optical film is assembled to display elements, such as a liquid crystal panel, using a polarizing plate etc., a problem arises that the change of contrast ratio changes with the orientation which observes the said display element.

In the optical film of the present invention, the value of the phase difference Rth (550) = {(nx + ny) / 2-nz} × d in the film thickness direction (where nz is the refractive index in the film thickness direction) is 30 nm to 200 nm. It is preferable, and it is more preferable that they are 50 nm-200 nm. Moreover, it is preferable that the maximum value of the angle (hereinafter also called "(theta) ₂ ") which the direction which shows the refractive index of a film thickness direction and the normal with respect to a film surface makes is 0 degrees-5 degrees, More preferably, it is 0 degrees-1 degree. Do.

The optical film of this invention can be obtained preferably by the manufacturing method 1 or the manufacturing method 2 mentioned above. The obtained optical film may be used as the stretched film as it is mentioned later as it is, or it may be wound up in roll shape once, and may be made into a film roll.

The thickness of the optical film used by this invention is 1-500 micrometers normally, Preferably it is 1-300 micrometers, More preferably, it is 2-200 micrometers. In the case of thickness less than 2 micrometers, handling becomes difficult substantially. On the other hand, when it is 500 micrometers or more, when a film is wound up in roll shape, a "wound trace" may arise and handling in post processing etc. may become difficult.

The thickness distribution of the optical film used in the present invention is usually within ± 20%, preferably within ± 10%, more preferably within ± 5%, particularly preferably within ± 1% of the average value. In addition, the variation in thickness per cm is usually 10% or less, preferably 5% or less, more preferably 1% or less, particularly preferably 0.5% or less. By performing thickness control in this way, an optical film with a smaller distribution of in-plane retardation and uniform optical characteristics and a stretched film obtained therefrom can be obtained.

Since the optical film of this invention is excellent in characteristics, such as transparency, heat resistance, water resistance, and chemical resistance, and excellent optical uniformity, it can be used as it is for optical films, such as a protective film, and also extends | stretches which expresses retardation further. By carrying out, it can use suitably for the use which manufactures retardation film with high uniformity.

Stretch  Method of Making Film

The manufacturing method of the stretched film of this invention is further characterized by extending | stretching the optical film of this invention to a film width direction or a film longitudinal direction. On the other hand, by adjusting the phase difference in the film surface in the optical film of this invention to arbitrary values, it becomes possible to obtain by extending | stretching the stretched film obtained by performing biaxial stretching of a longitudinal direction and the width direction normally only in the width direction. In addition, the optical film of the present invention can be further stretched in the longitudinal direction to further express the in-plane retardation.

As stretching conditions, it is maintained at the temperature of Tg-10 degreeC-Tg + 20 degreeC, Preferably Tg-5 degreeC-Tg + 15 degreeC of cyclic olefin resin which comprises an optical film, It is 1.1-5.0 times in the width direction or the longitudinal direction, Preferably Produces an optically uniform film by stretching in the range of 1.5 to 2.5 times.

Although it is preferable to use a tenter type transverse stretching machine as an apparatus used when extending | stretching a film in this invention, a simultaneous biaxial stretching machine can also be used.

The speed | rate at the time of extending | stretching a film is 1 to 5,000% / min normally, Preferably it is 50 to 1,000% / min, More preferably, it is 100 to 1,000% / min, Especially preferably, it is 100 to 500% / min.

The elongated film may be cooled as it is, but it is preferable to maintain and heat fix at least 10 seconds or more, preferably 30 seconds to 60 minutes, more preferably 1 minute to 60 minutes, under a temperature atmosphere of Tg-20 ° C to Tg. Do. Thereby, there exists little change of the phase difference of transmitted light with time, and a stable stretched film is obtained.

The stretched film which concerns on this invention is used suitably as retardation film, For example, it can laminate | stack on at least one surface of a polarizing film (polarizer), and can form a polarizing plate. The stretched film and the polarizing plate according to the present invention can be used for various optical components. For example, various liquid crystal displays and electroluminescent displays according to the present invention, such as mobile phones, digital information terminals, pagers, navigation, in-vehicle liquid crystal displays, liquid crystal monitors, dimming panels, displays for OA equipment, displays for AV equipment, and the like. It can be used for an element or a touch panel. It is also useful as a wave plate used for recording / reproducing apparatus of optical discs such as CD, CD-R, MD, MO, DVD.

<Example>

Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. In addition, below, "part" and "%" mean "weight part" and "weight%" unless there is particular notice.

In addition, in the following Examples, glass transition temperature, saturation absorption, total light transmittance, in-plane retardation of transmitted light, optical axis inclination angle of film thickness direction, transmittance and polarization degree of polarizing plate, reflectance, number of bright spots and scratch resistance are Was measured.

[Glass Transition Temperature (Tg)]

Using a differential scanning calorimeter (DSC) manufactured by Seiko Instruments Co., Ltd., the glass transition temperature was measured under a condition that the temperature increase rate was 20 ° C / min in a nitrogen atmosphere.

[Saturated Absorption Rate]

Based on ASTMD570, the sample was immersed in 23 degreeC water for 1 week, the weight change of the sample before and after immersion was measured, and the saturated water absorption was calculated | required from the value.

[Light transmittance]

The total light transmittance was measured using a haze meter "HM-150 type" manufactured by Murakami Color Research Institute.

[Optical Characteristics (R0, Rth, θ ₁ , θ ₂ )]

It measured at the wavelength of 550 nm using "KOBRA-21ADH" of Oji Keisoku Kiki Co., Ltd. product.

[Transmittance and Polarization Degree of Polarizing Plate]

The transmittance and polarization degree of the polarizing plate were measured using "KOBRA-21ADH" manufactured by Oji Keisoku Kiki Co., Ltd. The measurement wavelength was 550 nm.

Synthesis Example 1

225 parts of 8-methyl-8-carboxymethyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene as a specific monomer in a nitrogen-substituted reaction vessel, bicyclo [2.2.1] as a specific monomer 25 parts of hept-2-ene, 1 part of 1-hexene as a molecular weight regulator, and 750 parts of toluene as a solvent were put, and this solution was heated to 60 degreeC. Next, 0.62 parts of toluene solution containing 1.5 mol / l of triethylaluminum as a polymerization catalyst was added to the solution in the reaction vessel, and tungsten chloride (t-butanol: methanol: tungsten = 0.35 mol: 0.3) modified with t-butanol and methanol. 3.7 parts of toluene solution with a concentration of 0.05 mol / l containing 1 mol) were added, and this system was heated and stirred at 80 degreeC for 3 hours, and the ring-opening copolymer solution was obtained.

1,000 parts of the ring-opening polymer solution thus obtained were put in an autoclave, and 0.12 parts of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening polymer solution, and the hydrogen gas pressure was 100 kg / cm 2, and the reaction temperature was 165. The mixture was heated and stirred for 3 hours under the condition of ° C. to carry out a hydrogenation reaction, and after cooling the reaction solution (hydrogenated polymer solution) obtained, hydrogen gas was discharged. The reaction solution was placed in a desolvent apparatus, and the solvent was removed so as to be 500 ppm or less to obtain a pellet-shaped hydrogenated polymer (hereinafter referred to as "resin A1"). The hydrogenation rate measured using <^1> H-NMR of the said resin A1 was 99.9%.

The number average molecular weight (Mn) and weight average molecular weight (Mw) of polystyrene conversion were measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran) with respect to resin A1, and the number average molecular weight (Mn) was 20,800, weight The average molecular weight (Mw) was 62,000 and the molecular weight distribution (Mw / Mn) was 3.00. In addition, the glass transition temperature (Tg) of resin A1 was 130 degreeC, and the saturated water absorption at 23 degreeC was 0.3%. Moreover, it was 0.51 dl / g when the intrinsic viscosity ((eta) h) was measured in chloroform at 30 _degreeC .

<Manufacture example 1>

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

Subsequently, the polymer dispersion liquid was concentrated using an evaporator until the solid content concentration became 70%, thereby obtaining an aqueous pressure-sensitive adhesive (pressure-sensitive adhesive having a polar group) containing an aqueous dispersion of an acrylic acid ester polymer.

The number average molecular weight (Mn) in terms of polystyrene was determined by gel permeation chromatography (GPC, solvent: tetrahydrofuran) on the acrylic ester polymer constituting the aqueous adhesive (hereinafter referred to as "water-based adhesive A"). And as a result of measuring the weight average molecular weight (Mw), the number average molecular weight (Mn) was 69,000 and the weight average molecular weight (Mw) was 135,000.

Moreover, it was 1.2 dl / g as a result of measuring intrinsic viscosity ((eta) h) in 30 _degreeC chloroform with respect to the aqueous adhesive A.

Example 1

Resin A1 was extruded downstream with a gear pump using a twin screw extruder (manufactured by Toshiba Kikai Co., Ltd .; TEM-48), and a metal fiber sintered filter manufactured by Nihon Seisen Co., Ltd. having a nominal mesh of 10 μm was used. Melt filtration was carried out, and a coat hanger type T die (650 mm width) was used to extrude the membrane at 280 ° C. with a gap of 0.5 mm at the exit of the T die.

The extruded film was sandwiched between a cooling roll having a maximum value Rmax (µm) of surface roughness Rs coated with aluminum oxide and a metal belt having a thickness of 0.3 mm, and the surface of the film was transferred to a glossy surface.

Then, it peeled using the peeling roll whose maximum value Rmax (micrometer) of surface roughness Rs which surface-coated aluminum oxide was 0.1. At this time, the rotation speed of both rolls was adjusted so that the stress at the time of peeling might be 23 kgf / cm <2>, confirming with a temperature sensor so that the temperature of resin might be Tg + 3 degreeC by adjustment of roll temperature.

Then, the resin film peeled from the mirror surface roll was bonded with the polyethylene protective film of 50 micrometers in thickness, and the resin film (henceforth "resin film (a-1)") of 100 micrometers in thickness and 2000 m in length was obtained. . Table 1 shows the results of various evaluations of the resin film (a-1). In addition, the total light transmittance of the obtained resin film (a-1) was 93%.

Example 2

Using the resin film (a-1) obtained in Example 1, it extended | stretched by 1.5 times using the tenter-type transverse stretching machine at Tg + 10 degreeC, and obtained the resin film (a-2). Various evaluation results are summarized in Table 1. The total light transmittance of the said resin film (a-2) was 93%.

Example 3

A 50-micrometer-thick polyvinyl alcohol film was uniaxially stretched by 4 times for about 5 minutes while immersing in a 40 degreeC bath containing 5 g of iodine, 250 g of potassium iodide, 10 g of boric acid, and 1000 g of water to obtain a polarizing film. On the surface of this polarizing film, the resin film (a-2) manufactured in Example 2 was used for the resin film (a-1) manufactured in Example 1 to the one surface of a polarizing film using the water-based adhesive obtained by manufacture example 1. It bonded to the other side of the polarizing film, respectively, and obtained the polarizing plate 1 of 40% of transmittance | permeability and 99.9% of polarization degree. The polarization plate 1 was subjected to a durability test for 500 hours under conditions of 80 ° C. and 90% relative humidity, and the appearance change was visually observed. As a result, no abnormality in appearance such as whitening or swelling was observed. Also, the polarization degree was maintained at 95% or more with respect to the initial value, and it was confirmed that it had good durability. Moreover, when the said polarizing plate 1 was made into two cross nicol states, it bonded up and down to the cell of VA type liquid crystal television, and confirmed visibility, and was able to confirm favorable viewing angle compensation effect without a nonuniformity.

Comparative Example 1

In Example 1, the resin film (b-1) was obtained like Example 1 except having performed without adjusting the rotation speed of a cooling roll and a peeling roll. Various evaluation results of the resin film (b-1) are summarized in Table 1. In addition, the total light transmittance of the resin film (b-1) was 92%.

Comparative Example 2

Except having used the resin film (b-1), it extended | stretched like Example 2 and obtained the resin film (b-2). Various evaluation results of the resin film (b-2) are summarized in Table 1. The total light transmittance of the said resin film (b-2) was 92%.

Comparative Example 3

40% transmittance in the same manner as in Example 3 except that the resin film (b-1) was used instead of the resin film (a-1) and the resin film (b-2) was used instead of the resin film (a-2). The polarizing plate 2 of 99.9% of polarization degree was obtained. The endurance test of 500 hours was performed on this polarizing plate 2 on the conditions of 80 degreeC and 90% relative humidity, and when the external appearance change was observed visually, the external abnormality, such as whitening and expansion, was not seen at all, and also about polarization degree It was confirmed that 95% or more of polarization degree was maintained with respect to an initial value, and it has favorable durability. However, as a result of adhering to the VA type liquid crystal television with two polarizing plates 2 in the state of cross nicol, the visibility was confirmed, the light leakage was confirmed as a whole and a partial strong light leakage was seen, and the viewing angle compensation effect was insufficient.

According to the present invention, a cyclic olefin optical film having an arbitrary retardation, a small optical nonuniformity, and a long length can be produced by a simple method. Moreover, since optical nonuniformity is small, the optical film useful also as a raw material of a stretched film is obtained. Since the optical film and the stretched film according to the present invention have very little thickness fluctuation and little optical unevenness, a large liquid crystal display using the same can achieve high performance without deformation or unevenness over the whole surface.

Claims (9)

In the manufacturing process of the optical film which melt | dissolves cyclic olefin resin melted from die | dye, crimps | bonds to a base material, and peels a film from the said base material, and winds up in roll shape, until peeling a film from a base material and winding up in roll shape In any one process, it has a process of applying the stress of 1-30 kgf / cm <2> under the temperature of Tg-30 degreeC-Tg + 20 degreeC of the said cyclic olefin resin, The manufacturing method of the optical film characterized by the above-mentioned. The method for producing an optical film according to claim 1, wherein the film is peeled from the substrate at a stress of 1 to 30 kgf / cm 2 at a temperature of Tg-30 ° C to Tg + 20 ° C of the cyclic olefin resin when peeling the film from the substrate. . The cyclic olefin resin is dissolved or dispersed in an organic solvent to be flexible on the substrate, and a part of the organic solvent is removed to form a film composition. The film composition is peeled off from the substrate and the organic solvent is further removed to form a roll. In the manufacturing process of the optical film to wind up, in any one process until peeling a film composition from a base material and winding up in roll shape, it is 1-30 at the temperature of the apparent Tg-30 degreeC-Tg + 20 degreeC of the said film composition. Method of producing an optical film characterized by having a step of applying a stress of kgf / cm 2 (However, the apparent Tg of the film composition is measured by a DSC curve measured the temperature of the film composition at 20 ℃ / min temperature conditions Tg). When peeling a film composition from a base material, it peels from a base material with a stress of 1-30 kgf / cm <2> at the temperature of apparent Tg-30 degreeC-Tg + 20 degreeC of the said film-like composition, The optical film of Claim 3 characterized by the above-mentioned. (However, the apparent Tg of a film-like composition refers to Tg measured by the DSC curve which measured the said film-like composition on the temperature rising condition of 20 degree-C / min.). The refractive index of the direction which contains cyclic olefin resin, and shows the largest refractive index in the film plane at the light wavelength of 550 nm is set to nx, and the refractive index of the direction orthogonal to nx in a film plane is ny, and the film thickness is made d [nm]. When the phase difference R0 (550) [nm] = (nx-ny) xd in the film plane is 20 nm or more and 300 nm or less, and the variation of R0 is within ± 10%, the direction and film length indicating the maximum refractive index in the film plane The maximum value of the angle which a direction makes is 0 degrees-10 degrees, The optical film characterized by the above-mentioned. The cyclic olefin resin is a resin obtained by polymerizing or copolymerizing at least one compound represented by the following formula (1). <Formula 1>

In formula, R <^1> -R <^4> is a hydrogen atom, a halogen atom, a C1-C30 hydrocarbon group, or other monovalent organic group, respectively, may be same or different, and also any 2 of R <^1> -R <^4> . The dogs may combine with each other to form a monocyclic or polycyclic structure, m is zero or a positive integer, and p is zero or a positive integer. The optical film of Claim 5 or 6 is extended | stretched in the film width direction, The manufacturing method of the stretched film characterized by the above-mentioned. The optical film of Claim 5 or 6 is extended | stretched to a film longitudinal direction, The manufacturing method of the stretched film characterized by the above-mentioned. Subsequent to the method according to any one of claims 1 to 4, the obtained optical film is stretched in the film width direction, characterized in that the method for producing a stretched film.