JP2008055691A - Optical film roll and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which is homogeneous and uniform optically by minimizing foreign substances incorporated in a protective film in an optical film roll keeping the optical film overlaid/wound with the protective film. <P>SOLUTION: In the optical film roll making the optical film made of a cyclic olefin resin overlaid/wound with the protective film, the number of fish eyes with the diameters of at least 30 μm in the protective film is 5/m<SP>2</SP>or below. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical film roll formed by laminating and winding an optical film made of a cyclic olefin-based resin and a protective film. The optical film roll formed by laminating and winding the protective film of the present invention is cut out and used as various optical films such as a polarizing plate and a retardation plate, the protective film is used for surface protection, Such a protective film is applied to the surface of a liquid crystal display panel to protect various image display devices such as a liquid crystal display device and other organic EL display devices and PDPs.

  In general surface protection films, an adhesive layer is provided on a base film such as polyethylene terephthalate or polyethylene. The said surface protection film is bonded together to a to-be-protected body through an adhesive layer, and a damage | wound, contamination, etc. are prevented with respect to a to-be-protected body. For example, examples of the optical protection target include optical films such as a polarizing plate and a retardation plate.

  One side of these optical films is protected by a surface protective film in various production processes. On the other hand, an adhesive layer is provided on the opposite surface of the optical film. Further, a release liner (separator) is coated on the adhesive layer. The optical film with the surface protective film thus manufactured is stored in a roll-up state, or is cut according to the size of the liquid crystal cell, and is superposed on each other in a sheet form. Or keep it. These steps are usually performed in a clean room, but it is difficult to completely remove fine foreign matters such as dust generated by workers and inspectors, punching waste during punching, and dust during transportation.

  By the way, when minute foreign matter is mixed between the layers of the rolls or the overlapped films, a trace of the foreign matter is generated. If the optical film itself has a mark, it cannot be used in appearance. In addition, the pressure-sensitive adhesive layer has a lower elastic modulus than the optical film, and tends to have a mark. If the pressure-sensitive adhesive layer is imprinted, when the optical film is bonded to the LCD panel via the pressure-sensitive adhesive layer, air may be trapped in the indented portion and display may be poor.

In order to solve this problem, Patent Document 1 proposes a surface protective film in which a foreign material absorbing layer is provided on one side of a base film.
However, the foreign matter absorbing layer itself can be separately received in addition to the protective film and the base film, and providing this layer itself increases the number of steps, which complicates the steps when producing an optical film. Not only does this increase costs, but it is not economical.
JP 2005-125659 A

  An object of the present invention is to provide an optical film that is homogeneous and free from optical unevenness by suppressing foreign matter in the protective film as much as possible.

The present invention is an optical film roll formed by laminating and winding an optical film made of a cyclic olefin resin and a protective film, and the number of fish eyes having a diameter of 30 μm or more in the protective film is 5 / m ² or less. The present invention relates to an optical film roll.
Here, the cyclic olefin-based resin is preferably a (co) polymer of a compound represented by the following general formula (1).

(In Formula (1), R < ¹ > -R < ⁴ > is a hydrogen atom, a halogen atom, a C1-C30 hydrocarbon group, or another monovalent organic group, and may be the same or different. Further, any two of R ^{1 to} R ⁴ may be bonded to each other to form a monocyclic or polycyclic structure, m is 0 or a positive integer, and p is 0 or a positive integer. .)
Moreover, it is preferable that the centerline average roughness Ra of the said protective film is 0.005-0.05 micrometer.
Further, the protective film is preferably made of a polyolefin resin.
Next, the present invention is characterized in that an optical film made of a cyclic olefin-based resin and a protective film having a diameter of 30 μm or more and a number of fish eyes of 5 / m ² or less are overlapped and wound. The present invention relates to a method for producing an optical film roll.

  According to the present invention, in the conventional optical film roll, when the protective film having a fish eye that is laminated and wound is pressed against the surface of the optical film for a long time, it leads to minute unevenness of the surface, optical unevenness, When the protective film with less fish eyes of the present invention is used, a homogeneous optical film without optical unevenness can be obtained.

≪Optical film≫
The optical film of the present invention is an optical film made of a cyclic olefin resin.

<Cyclic olefin resin>
Examples of the cyclic olefin resin used in the optical film of the present invention include the following (co) polymers.
(1) A ring-opening polymer of a specific monomer represented by the general formula (I).
(2) A ring-opening copolymer of the specific monomer represented by the general formula (I) and a copolymerizable monomer.
(3) A hydrogenated (co) polymer of the ring-opening (co) polymer of (1) or (2) above.
(4) A (co) polymer obtained by cyclizing the ring-opening (co) polymer of (1) or (2) above by a Friedel-Craft reaction and then hydrogenating it.
(5) A saturated copolymer of the specific monomer represented by the general formula (I) and an unsaturated double bond-containing compound.
(6) Addition type (co) of one or more monomers selected from the specific monomer represented by the above general formula (I), vinyl cyclic hydrocarbon monomer and cyclopentadiene monomer Polymers and their hydrogenated (co) polymers.
(7) An alternating copolymer of the specific monomer represented by the general formula (I) and an acrylate.

<Specific monomer>
Specific examples of the specific monomer include the following compounds, but the present invention is not limited to these specific examples.
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
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,
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-phenyltetracyclo [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,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene.
These can be used alone or in combination of two or more.

Among the specific monomers, in general formula (I), R ¹ and R ³ are each 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, and m is 0 An integer of ˜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 in which m = 1 and p = 0 is preferable in that the cyclic olefin resin obtained has a high glass transition temperature and excellent mechanical strength.
Examples of the polar group of the specific monomer include a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, and a cyano group. These polar groups are connected via a linking group such as a methylene group. May be combined. 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 carboxyl group, a hydroxyl 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 material in which the obtained cyclic olefin-based resin has a high glass transition temperature, a low hygroscopic property, 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. In addition, n is usually 0 to 5, but the smaller the value of n, the higher the glass transition temperature of the resulting cyclic olefin resin, which is preferable, and the specific monomer having n of 0 is It is preferable in that the synthesis is easy.

In the general formula (I), R ¹ or R ³ is preferably an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms, particularly a methyl group. In particular, it is preferable that the alkyl group is bonded to the same carbon atom as the carbon atom to which the specific polar group represented by the above formula — (CH ₂ ) _n COOR is bonded. This is preferable in that the hygroscopicity can be lowered.

<Copolymerizable monomer>
Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.
The number of carbon atoms of the cycloolefin is preferably 4-20, and more preferably 5-12. These can be used alone or in combination of two or more.
A preferred use range of the specific monomer / copolymerizable monomer is 100/0 to 50/50, more preferably 100/0 to 60/40, in weight ratio.

<Ring-opening polymerization catalyst>
In the present invention, (1) a ring-opening polymer of a specific monomer, and (2) a ring-opening polymerization reaction for obtaining a ring-opening copolymer of a specific monomer and a copolymerizable monomer are metathesis It is carried out in the presence of a catalyst.
This metathesis catalyst comprises (a) at least one selected from W, Mo and Re compounds, (b) Deming periodic table group IA elements (for example, Li, Na, K, etc.), IIA group elements (for example, , Mg, Ca, etc.), Group IIB elements (eg, Zn, Cd, Hg, etc.), Group IIIA elements (eg, B, Al, etc.), Group IVA elements (eg, Si, Sn, Pb, etc.), or Group IVB A catalyst comprising a combination of at least one element selected from compounds having elements (for example, Ti, Zr, etc.) and having at least one element-carbon bond or the element-hydrogen bond. In this case, in order to increase the activity of the catalyst, an additive (c) described later may be added.

As typical examples of W, Mo or Re compounds suitable as the component (a), WCl ₆ , MoCl ₆ , ReOCl _{3 and the} like are disclosed in JP-A-1-132626, page 8, lower left column, line 6 to page 8, upper right. The compounds described in column 17th line can be mentioned.
(B) Specific examples of the _{component, n-C 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 , methylalumoxane, LiH and the like, the compounds described in JP-A-1-132626, page 8, upper right column, line 18 to page 8, lower right column, line 3 can be exemplified.
As typical examples of the component (c) which is an additive, alcohols, aldehydes, ketones, amines and the like can be suitably used, but further, JP-A-1-132626, page 8, lower right column, The compounds shown in line 16 to page 9, upper left column, line 17 can be used.

The amount of the metathesis catalyst used is a range in which “(a) component: specific monomer” is usually 1: 500 to 1: 50,000 in terms of the molar ratio of the component (a) to the specific monomer. The range is preferably 1: 1,000 to 1: 10,000.
The ratio of the component (a) to the component (b) is such that (a) :( b) is 1: 1 to 1:50, preferably 1: 2 to 1:30 in terms of metal atomic ratio.
The ratio of the component (a) to the component (c) is such that the molar ratio (c) :( a) is in the range of 0.005: 1 to 15: 1, preferably 0.05: 1 to 7: 1. The

<Solvent for polymerization reaction>
Examples of the solvent used in the ring-opening polymerization reaction (solvent constituting the molecular weight modifier solution, solvent for the specific monomer and / or metathesis catalyst) include alkanes such as pentane, hexane, heptane, octane, nonane, decane, Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, chlorobutane, bromohexane, methylene chloride, dichloroethane, hexamethylene dibromide, chlorobenzene, Compounds such as halogenated alkanes and aryl halides such as chloroform and tetrachloroethylene, saturated carbohydrates such as ethyl acetate, n-butyl acetate, iso-butyl acetate, methyl propionate, and dimethoxyethane Esters, dibutyl ether, tetrahydrofuran, and the like can be illustrated ethers such as dimethoxyethane, it can be used singly or in combination. Of these, aromatic hydrocarbons are preferred.
As the amount of the solvent used, “solvent: specific monomer (weight ratio)” is usually in an amount of 1: 1 to 10: 1, preferably in an amount of 1: 1 to 5: 1. The

<Molecular weight regulator>
The molecular weight of the resulting ring-opening (co) polymer can be adjusted by the polymerization temperature, the type of catalyst, and the type of solvent. In the present invention, the molecular weight is adjusted by allowing the molecular weight regulator to coexist in the reaction system. To do.
Here, suitable molecular weight regulators include, for example, α-olefins such as ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and the like. Styrene can be mentioned, and among these, 1-butene and 1-hexene are particularly preferable.
These molecular weight regulators can be used alone or in admixture of two or more.
The amount of the molecular weight regulator used is 0.005 to 0.6 mol, preferably 0.02 to 0.5 mol, per 1 mol of the specific monomer subjected to the ring-opening polymerization reaction.

  (2) In order to obtain a ring-opening copolymer, a specific monomer and a copolymerizable monomer may be subjected to ring-opening copolymerization in the ring-opening polymerization step, and further, polybutadiene, polyisoprene, etc. In the presence of unsaturated hydrocarbon polymers such as conjugated diene compounds, styrene-butadiene copolymers, ethylene-nonconjugated diene copolymers, polynorbornene and the like containing two or more carbon-carbon double bonds in the main chain. The specific monomer may be subjected to ring-opening polymerization.

Although the ring-opening (co) polymer obtained as described above can be used as it is, (3) the hydrogenated (co) polymer obtained by further hydrogenation is a resin having high impact resistance. It is useful as a raw material.
<Hydrogenation catalyst>
In the hydrogenation reaction, a hydrogenation catalyst is added to a usual method, that is, a solution of a ring-opening polymer, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm, is added thereto at 0 to 200 ° C., preferably 20 It is carried out by operating at ~ 180 ° C.
As a hydrogenation catalyst, what is used for the hydrogenation reaction of a normal olefinic compound can be used. Examples of the hydrogenation catalyst include a heterogeneous catalyst and a homogeneous catalyst.

  Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst material such as palladium, platinum, nickel, rhodium, and ruthenium is supported on a carrier such as carbon, silica, alumina, and titania. In addition, homogeneous catalysts include nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride, rhodium acetate, chlorotris (triphenylphosphine) rhodium. Dichlorotris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorocarbonyltris (triphenylphosphine) ruthenium, and the like. The form of the catalyst may be powder or granular.

These hydrogenation catalysts are used in such a ratio that the ring-opening (co) polymer: hydrogenation catalyst (weight ratio) is 1: 1 × 10 ⁻⁶ to 1: 2.
As described above, the hydrogenated (co) polymer obtained by hydrogenation has excellent thermal stability, and its characteristics deteriorate due to heating during molding and use as a product. There is no. Here, the hydrogenation rate is usually 50% or more, preferably 70% or more, and more preferably 90% or more.

The hydrogenation rate of the hydrogenated (co) polymer is 50% or more, preferably 90% or more, more preferably 98% or more, most preferably 99% or more, as measured by 500 MHz and ¹ H-NMR. is there. The higher the hydrogenation rate, the better the stability to heat and light. When the optical film of the present invention is used as a wave plate, stable characteristics can be obtained over a long period of time.
The hydrogenated (co) polymer used as the cyclic olefin resin of the present invention preferably has a gel content contained in the hydrogenated (co) polymer of 5% by weight or less. It is particularly preferable that the amount is not more than% by weight.

In addition, as the cyclic olefin-based resin of the present invention, (4) a (co) polymer obtained by cyclizing the ring-opened (co) polymer of the above (1) or (2) by a Friedel-Craft reaction and then hydrogenating it. Can be used.
<Cyclization by Friedel-Craft reaction>
The method for cyclizing the ring-opened (co) polymer of (1) or (2) by Friedel-Craft reaction is not particularly limited, but the acidic compound described in JP-A-50-154399 is used. Any known method can be employed. Specifically, Lewis acid such as AlCl ₃ , BF ₃ , FeCl ₃ , Al ₂ O ₃ , HCl, CH ₃ ClCOOH, zeolite, activated clay, and Bronsted acid are used as the acidic compound.
The cyclized ring-opening (co) polymer can be hydrogenated in the same manner as the ring-opening (co) polymer (1) or (2).

Furthermore, as the cyclic olefin resin of the present invention, (5) a saturated copolymer of the specific monomer and an unsaturated double bond-containing compound can also be used.
<Unsaturated double bond-containing compound>
As an unsaturated double bond containing compound, ethylene, propylene, butene etc., Preferably it is C2-C12, More preferably, C2-C8 olefin type compound can be mentioned.
The preferred use range of the specific monomer / unsaturated double bond-containing compound is 90/10 to 40/60, more preferably 85/15 to 50/50, in weight ratio.

In the present invention, in order to obtain a saturated copolymer of (5) a specific monomer and an unsaturated double bond-containing compound, a usual addition polymerization method can be used.
<Addition polymerization catalyst>
As the catalyst for synthesizing the (5) saturated copolymer, at least one selected from a titanium compound, a zirconium compound and a vanadium compound and an organoaluminum compound as a promoter are used.
Here, examples of the titanium compound include titanium tetrachloride and titanium trichloride, and examples of the zirconium compound include bis (cyclopentadienyl) zirconium chloride and bis (cyclopentadienyl) zirconium dichloride.

Moreover, as the vanadium compound, the general formula VO _(OR) a _{X b} or V _(OR) c _{X d,}
[Wherein R is a hydrocarbon group, X is a halogen atom, and 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ (a + b) ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 3, ≦ (c + d) ≦ 4. ]
Or an electron-donating adduct of these compounds.
Examples of the electron donor include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic acids or inorganic acids, ethers, acid amides, acid anhydrides, oxygen-containing electron donors such as alkoxysilanes, ammonia, amines, Examples thereof include nitrogen-containing electron donors such as nitrile and isocyanate.

Furthermore, as the organoaluminum compound as the promoter, at least one selected from those having at least one aluminum-carbon bond or aluminum-hydrogen bond is used.
In the above, for example, when the vanadium compound is used, the ratio of the vanadium compound to the organoaluminum compound is such that the ratio of aluminum atom to vanadium atom (Al / V) is 2 or more, preferably 2 to 50, particularly preferably 3 to 20. Range.

  As the solvent for the polymerization reaction used for the addition polymerization, the same solvent as that used for the ring-opening polymerization reaction can be used. Moreover, adjustment of the molecular weight of the (5) saturated copolymer obtained is normally performed using hydrogen.

Furthermore, as the cyclic olefin resin of the present invention, (6) an addition type of one or more monomers selected from the above specific monomer and a vinyl cyclic hydrocarbon monomer or a cyclopentadiene monomer Copolymers and their hydrogenated copolymers can also be used.
<Vinyl cyclic hydrocarbon monomer>
Examples of the vinyl cyclic hydrocarbon monomer include vinyl cyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene, 4-vinylcyclopentane, 4-isopropenylcyclopentane and the like. Vinylated 5-membered hydrocarbon monomers such as vinylcyclopentane monomers, 4-vinylcyclohexene, 4-isopropenylcyclohexene, 1-methyl-4-isopropenylcyclohexene, 2-methyl-4-vinyl Vinylcyclohexene monomers such as cyclohexene and 2-methyl-4-isopropenylcyclohexene, vinylcyclohexane monomers such as 4-vinylcyclohexane and 2-methyl-4-isopropenylcyclohexane, styrene, α-methylstyrene, 2-methylstyrene, 3- Styrenic monomers such as styrene styrene, 4-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-phenylstyrene, p-methoxystyrene, d-terpene, 1-terpene, diterpene, d-limonene, 1- Terpene monomers such as limonene and dipentene, vinylcycloheptene monomers such as 4-vinylcycloheptene and 4-isopropenylcycloheptene, 4-vinylcycloheptane, 4-isopropenylcycloheptane, etc. And vinyl cycloheptane monomers. Styrene and α-methylstyrene are preferable. These can be used alone or in combination of two or more.

<Cyclopentadiene monomer>
Examples of the cyclopentadiene monomer used as the monomer of the addition copolymer (6) of the present invention include, for example, cyclopentadiene, 1-methylcyclopentadiene, 2-methylcyclopentadiene, 2-ethylcyclopentadiene, Examples include 5-methylcyclopentadiene and 5,5-methylcyclopentadiene. Cyclopentadiene is preferred. These can be used alone or in combination of two or more.

The addition type (co) polymer of at least one monomer selected from the above specific monomer, vinyl cyclic hydrocarbon monomer and cyclopentadiene monomer is the above (5) specific monomer. It can be obtained by the same addition polymerization method as the saturated copolymer of the unsaturated double bond-containing compound.
The hydrogenated (co) polymer of the addition type (co) polymer can be obtained by the same hydrogenation method as the hydrogenated (co) polymer of the above (3) ring-opening (co) polymer. .

Furthermore, as the cyclic olefin resin of the present invention, (7) an alternating copolymer of the specific monomer and acrylate can also be used.
<Acrylate>
Examples of the acrylate used in the production of the (7) alternating copolymer of the specific monomer and acrylate of the present invention include straight chain having 1 to 20 carbon atoms such as methyl acrylate, 2-ethylhexyl acrylate and cyclohexyl acrylate. C2-C20 heterocyclic group-containing acrylates such as chain, branched or cyclic alkyl acrylates, glycidyl acrylates, 2-tetrahydrofurfuryl acrylates, and aromatic ring groups containing 6-20 carbons such as benzyl acrylates Examples thereof include acrylates having a polycyclic structure having 7 to 30 carbon atoms such as acrylate, isobornyl acrylate, and dicyclopentanyl acrylate.

In the present invention, (7) In order to obtain an alternating copolymer of the specific monomer and acrylate, when the total of the specific monomer and acrylate is 100 mol in the presence of Lewis acid, The specific monomer is 30 to 70 mol, the acrylate is 70 to 30 mol, preferably the specific monomer is 40 to 60 mol, and the acrylate is 60 to 40 mol, particularly preferably the specific monomer. The body undergoes radical polymerization at a rate of 45 to 55 mol and acrylate at a rate of 55 to 45 mol.
(7) The amount of Lewis acid used to obtain the alternating copolymer of the specific monomer and acrylate is 0.001 to 1 mol per 100 mol of acrylate. Also, known organic peroxides or azobis radical polymerization initiators that generate free radicals can be used, and the polymerization reaction temperature is usually -20 ° C to 80 ° C, preferably 5 ° C to 60 ° C. . Moreover, the same solvent as used for the ring-opening polymerization reaction can be used as the solvent for the polymerization reaction.
The “alternate copolymer” as used herein refers to a structure in which the structural unit derived from the specific monomer is not adjacent, that is, the structural unit derived from the acrylate is always adjacent to the structural unit derived from the specific monomer. It means a copolymer having a structure as a unit, and does not deny a structure in which structural units derived from acrylate are adjacent to each other.

The preferred molecular weight of the cyclic olefin resin used in the present invention is intrinsic viscosity [η] _inh (measured in chloroform at 30 ° C.), preferably 0.2 to 5 dl / g, more preferably 0.3 to 1. The number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 8,000 to 100,000, more preferably 5 dl / g, particularly preferably 0.35 to 0.8 dl / g. Is from 10,000 to 80,000, particularly preferably from 12,000 to 50,000, and the weight average molecular weight (Mw) is from 20,000 to 300,000, more preferably from 30,000 to 250,000, particularly preferably. Is preferably in the range of 40,000 to 200,000.
Inherent viscosity [η] _inh , number average molecular weight and weight average molecular weight are in the above ranges, so that heat resistance, water resistance, chemical resistance, mechanical properties of cyclic olefin resin and molding as an optical film of the present invention Workability is improved.

  As glass transition temperature (Tg) of cyclic olefin resin used for this invention, it is 110 degreeC or more normally, Preferably it is 110-350 degreeC, More preferably, it is 120-250 degreeC, Most preferably, it is 120-200 degreeC. When Tg is less than 110 ° C., it is not preferable because it is deformed by use under a high temperature condition or by secondary processing such as coating or printing. On the other hand, when Tg exceeds 350 ° C., the molding process becomes difficult, and the possibility that the resin deteriorates due to heat during the molding process increases.

  For the cyclic olefin-based resin, a specific hydrocarbon-based resin described in, for example, Japanese Patent Application Laid-Open Nos. 9-221577 and 10-287732, or a known heat can be used without departing from the effect of the present invention. Plastic resins, thermoplastic elastomers, rubber polymers, organic fine particles, inorganic fine particles and the like may be blended.

  In addition, to the cyclic olefin-based resin of the present invention, additives such as known antioxidants and ultraviolet absorbers may be added in order to improve heat resistance and light resistance within the range not impairing the effects of the present invention. Can do. For example, at least one compound selected from the group consisting of the following phenol compounds, thiol compounds, sulfide compounds, disulfide compounds, and phosphorus compounds is added in an amount of 0.001 part by weight based on 100 parts by weight of the cyclic olefin resin of the present invention. By adding 01 to 10 parts by weight, the heat deterioration resistance can be improved.

Phenolic compounds:
Examples of phenolic compounds include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) proonate], 1,6-hexanediol-bis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -3,5-triazine, penta Erythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N-hexamethylenebis 3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) ) Benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5- Methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, and the like. Preferably, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], particularly preferably octadecyl-3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate] and the like.

Thiol compounds:
Examples of thiol compounds include alkyl mercaptans such as t-dodecyl mercaptan and hexyl mercaptan, 2-mercaptobenzimidazole, 2-mercapto-6-methylbenzimidazole, 1-methyl-2- (methylmercapto) benzimidazole, 2-mercapto. -1-methylbenzimidazole, 2-mercapto-4-methylbenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-5,6-dimethylbenzimidazole, 2- (methylmercapto) benzimidazole, 1- Examples thereof include methyl-2- (methylmercapto) benzimidazole, 2-mercapto-1,3-dimethylbenzimidazole, mercaptoacetic acid and the like.

Sulfide compounds:
Examples of sulfide compounds include 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thiobis (4-methyl-6-t- Butylphenol), 2,4-bis (n-octylthiomethyl) -6-methylphenol, dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'- Examples thereof include thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), and ditridecyl 3,3′-thiodipropionate.

Disulfide compounds:
Disulfide compounds include bis (4-chlorophenyl) disulfide, bis (2-chlorophenyl) disulfide, bis (2,5-dichlorophenyl) disulfide, bis (2,4,6-trichlorophenyl) disulfide, bis (2-nitro Phenyl) disulfide, ethyl 2,2′-dithiodibenzoate, bis (4-acetylphenyl) disulfide, bis (4-carbamoylphenyl) disulfide, 1,1′-dinaphthyl disulfide, 2,2′-dinaphthyl disulfide, 1,2′-dinaphthyl disulfide, 2,2′-bis (1-chlorodinaphthyl) disulfide, 1,1′-bis (2-chloronaphthyl) disulfide, 2,2′-bis (1-cyanonaphthyl) Disulfide, 2,2′-bis (1-acetylnaphthyl) disulfide, Lauryl-3,3'-thiodipropionate and the like.

Phosphorus compounds:
Examples of phosphorus compounds include tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,6 -Di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, and the like.

  Further, benzophenone compounds such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone, benzotriazole compounds such as N- (benzyloxycarbonyloxy) benzotriazole, or 2-ethyloxanilide, 2- An oxanilide compound such as ethyl-2′-ethoxyoxanilide is added in an amount of 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight, with respect to 100 parts by weight of the cyclic olefin resin of the present invention. Thus, light resistance can be improved.

  In addition, when the cyclic olefin-based resin according to the present invention is formed into a film or the like by melt extrusion, an antioxidant added to prevent the resin from being thermally deteriorated due to a heat history at the time of melt extrusion. The choice is an important technical element. That is, when a film obtained by melt extrusion is stretched, the glass transition temperature (Tg) of the cyclic olefin resin to be melt-extruded so as not to decrease the retardation or to minimize the degree of decrease. It is preferable to use a hindered phenol compound having a melting point in the temperature range of + 20 ° C. to Tg + 130 ° C., preferably Tg + 30 ° C. to Tg + 130 ° C. as the antioxidant.

  If the melting point is less than + 20 ° C. than the Tg of the cyclic olefin resin to be melt-extruded, even if a hindered phenol-based compound is used, if the addition amount increases, the phase difference may be greatly reduced. . On the other hand, when the melting point exceeds + 130 ° C. higher than the Tg of the cyclic olefin resin to be melt-extruded, the antioxidant may not be dissolved during processing, which may cause film defects such as fish eyes and foreign matters. Further, even when the melting point is Tg + 20 ° C. to Tg + 130 ° C. of the cyclic olefin-based resin, when a compound other than the hindered phenol-based compound is used as an antioxidant, a reduction in retardation may be observed.

  Specific examples of the antioxidant preferably used when the cyclic olefin resin of the present invention is formed by melt extrusion include, for example, 1,3,5-trimethyl-2,4,6-tris (3,5- Di-t-butyl-4-hydroxybenzyl) benzene, N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide), tris- (3,5-di-t- Butyl-4-hydroxybenzyl) -isocyanate, tris (2,4-di-t-butylphenyl) phosphite, and the like, but the present invention is not limited thereto. Depending on the Tg of the cyclic olefin resin to be extruded, it may be unsuitable. In addition, as long as the effect of this invention is not impaired, these may be used in combination and may be used independently.

  The addition amount of these antioxidants is usually 0.01 to 5 parts by weight, preferably 0.05 to 4 parts by weight, and more preferably 0.1 to 1 part per 100 parts by weight of the cyclic olefin resin. .5 parts by weight. When the addition amount of the antioxidant is less than 0.01 parts by weight, a gel is likely to be generated in the resin during the extrusion process, and as a result, it may be recognized as a defect on the obtained film. There is not preferable. On the other hand, if the amount of the additive exceeds 5 parts by weight, it may cause the formation of eyes and the like during processing, and this eye and eyes may cause die lines, fish eyes on the film, and burns, which is not preferable.

Such antioxidant may be added when the cyclic olefin resin is produced, or may be blended together with the pellets of the cyclic olefin resin when melt-extruding.
In addition, when the cyclic olefin-based resin of the present invention is molded by melt extrusion, additives other than the above-mentioned antioxidants such as a lubricant, an ultraviolet absorber, a dye or a pigment are used within a range not impairing the effects of the present invention. be able to. Of course, even in this case, in the case of an additive having a melting point, the melting point is preferably in the range of the melting point of the essential antioxidant of the present invention.

<Film forming>
Examples of the method for forming the cyclic olefin resin film include a solvent casting method (solution casting method) and a melt extrusion method. The solvent cast method is preferable in terms of good film thickness uniformity and surface smoothness, and the melt extrusion method is preferable in terms of production cost.

[Solvent casting method]
It does not specifically limit as a method of obtaining a cyclic olefin resin film by a solvent cast method, What is necessary is just to apply a well-known method. For example, a method of dissolving or dispersing the cyclic olefin resin in a solvent to obtain a liquid having an appropriate concentration, pouring or coating on a suitable base material, drying it, and then peeling it from the base material. .
Below, although various conditions of the method of obtaining a cyclic olefin resin film by a solvent cast method are shown, this invention is not limited to these conditions.

When the cyclic olefin-based resin is dissolved or dispersed 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. . If the concentration of the resin is lower than the above range, it is difficult to ensure the thickness of the film, and the surface smoothness of the film tends to be difficult to obtain due to foaming accompanying solvent evaporation. On the other hand, when the concentration exceeds the above range, the viscosity and the surface of the cyclic olefin resin film obtained by excessively increasing the solution viscosity tend to be difficult to be uniform.
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 50,000 mPa · s, and particularly preferably 1, 000 to 40,000 mPa · s.

Examples of the solvent 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, cyclohexanone, methyl ethyl ketone, and 4-methyl. Ketone solvents such as 2-pentanone; ester solvents such as methyl lactate and ethyl lactate; cycloolefin solvents such as cyclohexane, ethylcyclohexane and 1,2-dimethylcyclohexane; 2,2,3,3-tetrafluoro- Examples include halogen-containing solvents such as 1-propanol, methylene chloride, and chloroform; ether solvents such as tetrahydrofuran and dioxane; alcohol solvents such as 1-pentanol and 1-butanol.
In addition to the above, the SP value (solubility parameter) is 10 to 30 (MPa ^1/2 ), preferably 10 to 25 (MPa ^1/2 ), more preferably 15 to 25 (MPa ^1/2 ), particularly preferably. If a solvent in the range of 15 to 20 (MPa ^1/2 ) is used, a cyclic olefin resin film having good surface uniformity and optical properties can be obtained.
The said solvent may be used individually by 1 type, or 2 or more types may be mixed and used for it. In the case of a mixed system, the SP value range when the mixed system is used is preferably within the above range. At this time, the value of the SP value in the mixed system can be predicted by a weight ratio. For example, in the case of mixing two kinds, if the respective weight fractions are W1 and W2, and the SP values are SP1 and SP2, The SP value is the following formula:
SP value = W1 · SP1 + W2 · SP2
It can ask for.

As a method for applying the solution onto the substrate, for example, a spray method, a brush coating method, a roll coating method, a spin coating method, a dipping method, and the like can be employed in addition to a method using a die or a coater. In addition, you may control thickness, surface smoothness, etc. by apply | coating repeatedly.
Examples of the substrate include metal drums, steel belts, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and polytetrafluoroethylene (trade name; Teflon (registered trademark)) belts. .
There is no restriction | limiting in particular about the drying process of the said solvent cast method, It can implement by the method generally used, for example, the method of passing through a drying furnace through many rollers. However, if bubbles are generated as the solvent evaporates during the drying process, the characteristics of the film will be significantly reduced. To avoid this, the drying process is divided into two or more stages, and the temperature and air volume in each process are controlled. It is preferable to do. In particular, the drying process until peeling from the substrate is a plurality of steps of two or more steps, the temperature in the first drying step is 0 to 50 ° C., preferably 10 to 40 ° C., and the drying step in the second and subsequent steps. When the temperature is 50 to 200 ° C., preferably 70 to 180 ° C., the value of Rth (550) of the obtained film can be adjusted to a preferable range (30 to 300 nm), which is very preferable.
Furthermore, in order to set the retardation R0 (550) in the film plane to 0 to 300 nm, the stress T _F (MPa) during film peeling is preferably in the range of 0.01 MPa ≦ T _F ≦ 5 MPa. If _TF is less than 0.01 MPa, the film cannot be peeled well. On the other hand, if the film is peeled from the roll exceeding 5 MPa, R0 (550)> 300 nm, which is not preferable.
Here, the maximum refractive index in the film plane at a light wavelength of 550 nm is nx, the refractive index in the direction orthogonal to nx in the film plane is ny, the refractive index in the film thickness direction is nz, and the film thickness is d [nm]. And when
In-plane retardation R0 (550) [nm] = (nx−ny) × d
Thickness direction retardation Rth (550) [nm] = {(nx + ny) / 2−nz} × d
It is represented by
If the in-plane retardation R0 (550) exceeds 300 nm, light leakage is likely to occur, and the contrast ratio may be reduced.
In addition, when the value of retardation Rth (550) in the film thickness direction is within the above range, when the optical film is used for viewing angle compensation, the obtained liquid crystal panel has a large contrast ratio and a color shift. The viewing angle characteristics become very good as the size becomes smaller.

[Melt extrusion method]
It does not specifically limit as a method of obtaining a cyclic olefin resin film by a solvent cast method, What is necessary is just to apply a well-known method. For example, a method of extruding a molten cyclic olefin-based resin from a die attached to an extruder, press-bonding the resin to the surface of a mirror surface roll, and then cooling and peeling off to form a sheet can be mentioned.

As a method of melting the cyclic olefin-based resin, a method of melting the resin by an extruder is preferable, and the molten resin is quantitatively supplied by a gear pump, and this is filtered through a metal filter or the like to remove impurities, and then is die-cast. A method of extruding while forming into a film shape is preferable.
Examples of the method for cooling the film extruded from the die to form a sheet include a nip roll method, an electrostatic application method, an air knife method, a calendar method, a single-sided belt method, a double-sided belt method, and a three-roll method. In order to manufacture a sheet with less distortion, a single-sided belt type, in particular, a sheet manufacturing apparatus called a sleeve type, an electrostatic application method, or the like is preferably used. For example, there is a film manufacturing apparatus in which a mirror roll and a metal belt are arranged below the discharge port of the die, and a peeling roll is arranged in parallel with the mirror roll. The metal belt is held in a state where tension is applied by two holding rolls provided so as to be in contact with the inner surface thereof. The resin discharged from the discharge port is sandwiched between the mirror roll and the metal belt, is transferred to the mirror roll and cooled, and is then peeled off by the peeling roll to form a film. In addition, by placing the film on the mirror roll side from the charging electrode, placed at the both ends of the discharged film so as to face the mirror roll below the die outlet, without causing optical distortion. A method for improving the surface property of the film is also a preferable method.
As the extruder, any of a single screw, a twin screw, a planetary type, a kneader and the like may be used, but a single screw extruder is preferably used. Further, examples of the screw shape of the extruder include a vent type, a tip dull mage type, a full flight type, and the like, and a full flight type is preferable. The gear pump used for measuring the resin may be either an internal lubrication type or an external lubrication type, but the external lubrication type is preferred.

  Examples of the filter used for filtering foreign substances include a leaf disc type, a candle filter type, a leaf type, and a screen mesh. Among them, the leaf disk type is most preferable for the purpose of reducing the residence time distribution of the resin, and the nominal opening means the opening of the filter is 20 μm or less, preferably 10 μm or less, more preferably 5 μm or less. It is. Most preferably, it is 3 μm or less. When the nominal opening is larger than 20 μm, it is difficult to remove gels and the like in addition to visible foreign substances, so that it is not preferable as a filter for making an optical film.

  As a die, it is essential to make the resin flow inside the die uniform, and in order to keep the film thickness uniform, it is essential that the pressure distribution inside the die near the die exit is constant in the width direction. It is. Manifold dies, fishtail dies, coat hanger dies, and the like can be used to satisfy such conditions, and among these, coat hanger dies are preferable. A bending lip type is preferable for adjusting the flow rate of the die. A die having a function of adjusting thickness by automatic control by a heat bolt method is particularly preferable. Installing a choke bar to adjust the flow rate or attaching a lip block to adjust the thickness creates a step in the mounting part, or traps air or the like in the gap of the mounting part. This is not preferable because it may cause generation or die line. The discharge port of the die is preferably coated with a carbide coating such as tungsten carbide. Examples of the material of the die include SCM steel and stainless steel such as SUS, but are not limited thereto. In addition, the surface is plated with chromium, nickel, titanium, etc., and the film such as TiN, TiAlN, TiC, CrN, DLC (diamond-like carbon) is formed by PVD (Physical Vapor Deposition) method, etc. Further, a ceramic sprayed one, a surface nitrided one, etc. can be used. Since such a die has high surface hardness and low friction with the resin, it is possible to prevent burnt dust and the like from being mixed into the transparent resin sheet obtained and to prevent the occurrence of die lines. It is preferable at the point which can do.

The mirror roll preferably has a heating means and a cooling means inside, and its surface roughness is preferably 0.5 μm or less, particularly preferably 0.3 μm or less. As the mirror roll, it is preferable to use a metal roll plated, and a chromium roll or electroless nickel plated is particularly preferred.
As a method for heating the mirror surface roll, a jacket type oil temperature control method, a dielectric heating method, or the like is preferably used. The method for heating the roll is not particularly limited, but the roll temperature is preferably within the film-forming range, and there is preferably no temperature difference, and the allowable roll temperature difference is preferably within 2 ° C, more preferably within 1 ° C. .

  As a metal belt used for a single-sided belt type device or a sleeve type take-up device, it is preferable to use a seamless endless belt. As a material constituting the metal belt, stainless steel, nickel, or the like can be used. Moreover, it is preferable that the surface of the holding roll for holding the metal belt is coated with silicone rubber or other heat-resistant elastomer. The thickness of the metal belt is preferably 0.1 to 0.4 mm, and if it is less than 0.1 mm, the deflection is large and the belt may be damaged immediately, which is not preferable. On the other hand, if it is thicker than 0.4 mm, it is not preferable because it does not deform following the film during processing.

With the above apparatus, for example, a film is produced as follows.
Usually, before introducing a cyclic olefin resin into an extruder, the glass transition temperature (Tg) of the resin is removed for the purpose of removing moisture, gas (oxygen, etc.), residual solvent, etc. contained in the resin in advance. ) Dry the resin at the appropriate temperature below.
As the dryer used for drying, an inert gas circulation dryer or a vacuum dryer is preferably used. It is also preferable to use a vacuum hopper that can absorb moisture in the hopper or seal the hopper with an inert gas such as nitrogen or argon, or can be kept in a reduced pressure state in order to suppress oxygen absorption.
The extruder cylinder is preferably sealed with an inert gas such as nitrogen or argon in order to prevent the resin from being oxidized during the melt extrusion and generating a gel or the like.
The cyclic olefin-based resin melted by the extruder is extruded in a sheet shape from the die discharge port toward the lower side which is the vertical direction. The temperature distribution at the die outlet is preferably controlled to ± 1 ° C. or less in order to reduce the difference in melt viscosity of the resin.
Thereafter, the extruded resin is clamped and cooled by a mirror roll and a metal belt. And the resin transcribe | transferred by the mirror surface roll surface peels from the surface of a mirror surface roll with the roll for peeling, and a sheet-like film is manufactured.

In the present invention, the processing temperature of the resin, that is, the set temperature of the extruder and the die is such that the molten resin having a uniform fluidity can be discharged from the die and the resin can be prevented from being deteriorated. Tg + 100 ° C. or higher and Tg + 200 ° C. or lower is preferable.
In addition, when the resin is sandwiched between the mirror roll and the metal belt, that is, when the resin is transferred to the mirror roll, the pressure is preferably 0.01 to 0.8 MPa, particularly preferably 0.1 to 0. .6 MPa. Particularly preferred is 0.15 to 0.45 MPa. The above pressure is very preferable because the Rth (550) value of the obtained film can be adjusted to an appropriate range.

At this time, in order to set the angle θ formed by the optical axis in the film thickness direction and the normal to the film surface to 0 to 3 °, it is preferable to make the peripheral speed of the mirror roll and the metal belt close to each other. As a preferable range, when the peripheral speed of the mirror roll is 1.00, the peripheral speed of the metal belt is 0.95 to 1.05, particularly preferably 0.99 to 1.01. Within such a peripheral speed range, an angle θ formed by the optical axis in the film thickness direction and the normal to the film surface can be produced at 0 to 3 °. If θ exceeds 3 °, the color shift and contrast ratio differ depending on the orientation in which the liquid crystal panel is observed, and are not preferable because they are asymmetric with respect to the transmission axis of the polarizing plate.
Furthermore, in order to set the retardation R0 (550) in the film plane to 0 to 300 nm, when the peeling temperature T _t (° C.) and the peeling stress T _F (MPa) are used as the conditions at the time of film peeling, Tg− It is preferable that the ranges are 30 ° C. ≦ T _t ≦ Tg + 5 ° C. and 0.01 MPa ≦ T _F ≦ 5 MPa. When the film is peeled from the roll beyond this range, R0 (550)> 300 nm is not preferable.

<Film stretching process>
The optical film of the present invention can be further stretched from the optical film obtained by the casting method or the melt extrusion method as described above. Specific examples of the stretching method in this case include a known uniaxial stretching method or biaxial stretching method. That is, the horizontal uniaxial stretching method by the tenter method, the inter-roll compression stretching method, the longitudinal uniaxial stretching method using two sets of rolls with different circumferences, or the biaxial stretching method combining the horizontal uniaxial and the longitudinal uniaxial, inflation method The stretching method by, for example, can be used.
In the case of the uniaxial stretching method, the stretching speed is usually 1 to 5,000% / minute, preferably 50 to 1,000% / minute, more preferably 100 to 1,000% / minute, Particularly preferred is 100 to 500% / min.
In the case of the biaxial stretching method, stretching may be performed in two directions at the same time, or the stretching may be performed in a direction different from the first stretching direction after uniaxial stretching. At this time, the intersecting angle of the two stretching axes for controlling the shape of the refractive index ellipsoid of the film after stretching is not particularly limited because it is determined by desired characteristics, but is usually in the range of 120 to 60 degrees. It is. The stretching speed may be the same or different in each stretching direction, and is usually 1 to 5,000% / min, preferably 50 to 1,000% / min, more preferably Is from 100 to 1,000% / min, particularly preferably from 100 to 500% / min.

The stretching temperature is not particularly limited, but is usually Tg ± 30 ° C., preferably Tg ± 15 ° C., more preferably Tg−5 ° C. to Tg + 15 based on the glass transition temperature Tg of the resin of the present invention. It is in the range of ° C. Within the above range, it is possible to suppress the occurrence of phase difference unevenness, and it is preferable because the control of the refractive index ellipsoid becomes easy.
The draw ratio is not particularly limited because it is determined by desired properties, but is usually 1.01 to 10 times, preferably 1.03 to 5 times, and more preferably 1.03 to 3 times. When the draw ratio exceeds 10 times, it may be difficult to control the phase difference.

  Although the stretched film may be cooled as it is, it is heat set by holding it in a temperature atmosphere of Tg-20 ° C. to Tg for at least 10 seconds, preferably 30 seconds to 60 minutes, more preferably 1 minute to 60 minutes. It is preferable to do. As a result, a stable retardation film can be obtained with little change over time in the retardation of transmitted light.

The dimensional shrinkage ratio due to heating of the optical film of the present invention when not subjected to stretching is usually 5% or less, preferably 3% or less, more preferably 1% or less when heating at 100 ° C. for 500 hours. Especially preferably, it is 0.5% or less.
Further, the dimensional shrinkage ratio due to heating of the optical film of the present invention is usually 10% or less, preferably 5% or less, more preferably 3% or less, particularly preferably 1 when heating at 100 ° C. for 500 hours. % Or less.
In order to make the dimensional shrinkage rate within the above range, it is possible to control by a casting method and a stretching method in addition to selection of a specific monomer or copolymerizable monomer that is a raw material of the resin of the present invention. .

  In the film stretched as described above, molecules are oriented by stretching and a phase difference is given to transmitted light. This phase difference can be controlled by a stretching ratio, a stretching temperature, a film thickness, or the like. . For example, when the thickness of the film before stretching is the same, the larger the stretching ratio, the larger the absolute value of the retardation of transmitted light tends to increase. Therefore, the desired retardation can be transmitted by changing the stretching ratio. A retardation film applied to light can be obtained. On the other hand, when the stretch ratio is the same, the greater the thickness of the film before stretching, the greater the absolute value of the retardation of transmitted light tends to increase. Therefore, by changing the thickness of the film before stretching, the desired value can be obtained. A retardation film that imparts retardation to transmitted light can be obtained. Further, in the above stretching processing temperature range, the lower the stretching temperature, the larger the absolute value of the retardation of the transmitted light tends to increase. Therefore, the retardation film gives the desired retardation to the transmitted light by changing the stretching temperature. Can be obtained.

  The thickness of the optical film (retardation film) obtained by stretching as described above is usually 100 μm or less, preferably 100 to 20 μm, and more preferably 80 to 20 μm. By reducing the thickness, it is possible to greatly meet the demands for miniaturization and thinning required for products in the field where retardation films are used. Here, the thickness of the retardation film can be controlled by controlling the thickness of the optical film before stretching or by controlling the stretching ratio. For example, the thickness of the retardation film can be further reduced by thinning the optical film before stretching or by relatively increasing the stretching ratio.

  The amount of residual solvent in the film used for the optical film of the present invention is usually 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably 0.5% by weight or less. is there. Here, if the amount of residual solvent exceeds the above range, the dimensional change with time tends to increase when actually used, and the residual solvent may lower Tg and reduce heat resistance.

The thickness distribution of the film is usually within ± 10%, preferably within ± 5%, more preferably within ± 1%, and particularly preferably within ± 0.5% with respect to the average value. The thickness variation per 1 cm is usually 1% or less, preferably 0.1% or less, more preferably 0.01% or less, and particularly preferably 0.005% or less. By controlling the thickness distribution of the optical film within the above range, it is possible to prevent the occurrence of uneven retardation and uneven alignment of the optical axis when the stretching process is performed in some cases.
Here, the thickness distribution is a value measured at an interval of 1 mm by a film thickness measuring device “Profiler 140E” manufactured by MOCON.

≪Protective film≫
The protective film of the present invention is for protecting the surface of an optical film made of a cyclic olefin resin, and the optical film and the protective film are laminated and wound to constitute the optical film roll of the present invention.

  Here, the protective film of the present invention may have an adhesive layer on one side of the protective film, or may have an adhesive layer on one side of the protective film and a conductive layer on the other side. May be.

  As the material of the protective film used in the present invention, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, and the like is preferable. For example, a polyester-based polymer such as polyethylene terephthalate or polyethylene naphthalate, Cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), polycarbonate polymers, polyethylene, polypropylene, cyclo or Olefin resin having norbornene structure, EP (D) M such as ethylene / propylene copolymer, vinyl chloride polymer, amide polymer such as nylon and aromatic polyamide, imide polymer -, Sulfone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy Or a blend of the above polymers. Preferably, from the viewpoint of preventing the optical film from being damaged by the protective film, an olefin resin such as polyethylene and polypropylene is preferable.

  Various additives, such as a light stabilizer, a ultraviolet absorber, antioxidant, a filler, can be mix | blended with a protective film as needed. Further, a known surface modification treatment such as corona treatment can be performed.

  It is preferable that the film thickness of a protective film is 5-50 micrometers, More preferably, it is 5-30 micrometers. If it is thinner than 5 μm, it tends to be difficult to produce, whereas if it is thicker than 50 μm, it tends to be expensive.

Protective film used in the present invention, it is necessary that a diameter contained in the film (phi) is equal to or more than the fish eyes 30μm five / m ² or less. Preferably, it is 1 piece / m ² or less. Here, the fish eye refers to a material in which a material to be a protective film is melted by heat and kneaded, extruded, or a film is produced by an extrusion stretching method or a casting method, in which undissolved and deteriorated materials are taken into the film. .
In addition, although the magnitude | size of the diameter of a fish eye changes with materials, it is about 10 micrometers-1 mm, and the height from the film surface is about 1-50 micrometers.
Here, the measurement method of the size of the fish eye can be measured by, for example, an optical microscope, a contact surface roughness meter, or a scanning electron microscope. The diameter (φ) of the fish eye means the maximum diameter.
In the protective film of the present invention, when the number of fish eyes having a diameter of 30 μm or more exceeds 5 / m ² , when the optical film and the protective film are laminated and wound as an optical film roll, the protective film having fish eyes can be used for a long time. When pressed against the surface of the optical film, minute irregularities are formed on the surface of the optical film, leading to optical unevenness.

  In addition, as surface roughness of a protective film, it is preferable that centerline average roughness Ra is 0.005-0.05 micrometer, and it is more preferable that it is 0.01-0.03 micrometer. The surface roughness can be measured using a contact-type surface roughness meter.

As described above, the protective film suitably used in the present invention having a good fish eye level is, for example, when manufacturing a film, using a polymer filter having a fine opening of 10 μm or less after heat melting the raw material resin, foreign matter, gel, etc. The film can be produced by changing the film production method, such as filtration.
As commercially available polyolefin protective films, PP-type PT manufactured by Shin-Etsu Film Co., Ltd., Torayfan BO-2400 and YR12 type manufactured by Toray Industries, Toraytec # 7332 manufactured by Toray Film Co., Ltd., and Alphan E200 manufactured by Oji Paper Co., Ltd. In addition to the series, 6221SC-30 manufactured by Sekisui Chemical Co., Ltd., PAC-3 manufactured by Sanei Kaken Co., Ltd., and the like are exemplified, but the present invention is not limited thereto.

  In addition, as an adhesive which comprises the adhesive layer which may be formed in the single side | surface of a protective film, the re-peeling adhesive (acrylic type, rubber type, synthetic rubber type etc.) normally used can be especially used without a restriction | limiting. . Among these, an acrylic pressure-sensitive adhesive that is excellent in adhesiveness, processability, durability, and the like, and whose adhesive force can be easily controlled by the composition is preferable. The pressure-sensitive adhesive layer is preferably crosslinked with a crosslinking agent.

  Furthermore, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like can be appropriately used for the pressure-sensitive adhesive as necessary.

The method for forming the pressure-sensitive adhesive layer is not particularly limited. The pressure-sensitive adhesive layer is applied to a silicone-treated polyester film, dried and then transferred to a protective film (transfer method), and the pressure-sensitive adhesive composition is directly applied to the protective film. And a drying method (direct copying method) and a co-extrusion method.
Although the thickness in particular of an adhesion layer is not restrict | limited, About 3-100 micrometers is preferable and about 5-40 micrometers is more preferable.

In addition, it is preferable to form a conductive layer on the surface opposite to the surface on which the adhesive layer of the protective film is formed.
The conductive layer is formed by blending an antistatic agent such as a surfactant, conductive carbon, and metal powder with a commonly used polymer such as polyester, and molding it on a transparent substrate film. It can be formed by a method in which an agent or a conductive resin is applied and dried, and a method in which a conductive material such as a metal or a conductive metal oxide is applied, evaporated or plated on the protective film.

  The thickness of the conductive layer is not particularly limited, but is preferably about 0.01 to 1 μm, and particularly preferably about 0.03 to 0.8 μm. If the thickness of the conductive layer is less than 0.01 μm, the antistatic effect and the effect of removing static electricity will be poor, and if it is thicker than 1 μm, the light transmittance will be unfavorable.

≪Optical film roll≫
The optical film roll of the present invention is formed by laminating and winding an optical film made of the above cyclic olefin-based resin and a protective film.
Here, in order to laminate and wind the optical film and the protective film, the optical film and the protective film are sandwiched between a mirror roll whose rotational speed is controlled so as to have a constant tension and a rubber roll that is moved up and down by air. A method of combining them is preferably used.
In order to prevent winding deviation, it is a preferable method as a winding method using an edge position control system (EPC) or the like while preventing deviation at both ends of the film.

≪Polarizing plate≫
The polarizing plate of the present invention comprises an optical film of the present invention, which is a viewing angle compensation film, on at least one surface of a polarizer made of a PVA-based film, an aqueous adhesive composed of an aqueous solution mainly composed of PVA resin, and a polar group-containing viscosity. It is manufactured by laminating using an adhesive, a photo-curable adhesive, etc., heating or exposing as necessary, and pressing and bonding (laminating) the polarizer and the viewing angle compensation film. be able to.

≪LCD panel≫
In the liquid crystal panel of the present invention, the polarizing plate of the present invention is bonded to at least one surface of a liquid crystal display element in which liquid crystal is sandwiched between two glass substrates, and the liquid crystal display element and the polarizing plate are bonded (laminated). Can be manufactured. At this time, polarizing plates are used on both surfaces of the glass substrate.

Specific examples of the present invention will be described below, but the present invention is not limited to these examples.
In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.
Further, in the following examples, the glass transition temperature, the saturated water absorption, the dotted defects of the protective film, the total light transmittance, the haze, the in-plane retardation of the transmitted light, the transmittance of the polarizing plate and the degree of polarization are as follows: Measured by the method.

[Glass transition temperature (Tg)]
Using a differential scanning calorimeter (DSC) manufactured by Seiko Instruments Inc., the glass transition temperature was measured in a nitrogen atmosphere under a temperature rising rate of 20 ° C./min.
[Saturated water absorption]
In accordance with ASTM D570, the sample was immersed in water at 23 ° C. for 1 week, the change in the weight of the sample before and after immersion was measured, and the saturated water absorption was determined from the value.
[Fisheye / Point-like defect measurement]
A protective film or an optical film was rolled up 10 m ² and placed on black paper, and the fluctuation of reflected light was confirmed under a 100 w fluorescent lamp. The portion where the reflected light fluctuated was regarded as a point defect of the fish-eye / optical film of the protective film, and the portion was counted. Thereafter, the film was observed with a microscope at a magnification of 50 times to count the number of fish eyes or point defects of 30 μm or more.
The observation of point defects on the roll-shaped optical film was performed in the same manner.
[Total light transmittance, haze]
Using a haze meter “HM-150 type” manufactured by Murakami Color Research Laboratory, total light transmittance and haze were measured.
[In-plane retardation of transmitted light (R0)]
Using “KOBRA-21ADH” manufactured by Oji Scientific Instruments, the in-plane retardation (R0) when light was incident on the film perpendicularly was measured at a wavelength of 550 nm.
[Transmissivity and degree of polarization of polarizing plate]
Using “RETS” manufactured by Otsuka Electronics Co., Ltd., the transmittance and polarization degree of the polarizing plate were measured. The measurement wavelength was 550 nm.
[Film thickness distribution]
It measured in the film longitudinal direction using the film thickness distribution measuring apparatus (MOCON).

<Preparation Example 1>
The reaction vessel was charged with 250 parts of distilled water, and after adding 90 parts of butyl acrylate, 8 parts of 2-hydroxyethyl methacrylate, 2 parts of divinylbenzene, and 0.1 part of potassium oleate, The system was dispersed by stirring with a stirring blade made of polytetrafluoroethylene (Teflon: registered trademark). Thereafter, the inside of the reaction vessel was purged with nitrogen, and then the temperature of the system was raised to 50 ° C., and 0.2 part of potassium persulfate was added to initiate polymerization. After 2 hours from the start of the polymerization, 0.1 parts of potassium persulfate was further added to the polymerization reaction system, and then the system was heated to 80 ° C. and the polymerization reaction was continued for 1 hour to obtain a polymer dispersion. Got.
Then, using an evaporator, the aqueous dispersion (adhesive having a polar group) composed of an aqueous dispersion of an acrylate-based polymer is concentrated by concentrating the polymer dispersion until the solid content becomes 70%. Obtained.
The acrylic ester polymer constituting the aqueous adhesive (hereinafter referred to as “aqueous adhesive A”) thus obtained is subjected to gel permeation chromatography (GPC, solvent: tetrahydrofuran) and converted into polystyrene. When the average molecular weight (Mn) and the weight average molecular weight (Mw) were measured, the number average molecular weight (Mn) was 69,000, and the weight average molecular weight (Mw) was 135,000.
Moreover, when the intrinsic viscosity ((eta) _inh ) was measured about 30 degreeC chloroform about the water-based adhesive A, it was 1.2 dl / g.

[Example 1]
A norbornene resin (manufactured by JSR Corporation: trade name “ARTON D4531”, glass transition temperature 130 ° C.) was used as the cyclic olefin resin. This raw material is dehumidified and dried under nitrogen at a drying temperature of 100 ° C., led to an extruder (GM Engineering Co., Ltd .: GM-65), melted at 260 ° C., and fed in a fixed amount using a gear pump, and a 5 μm leaf disk. Foreign matters were removed using a filter, and extrusion was performed from a T die heated by an aluminum casting heater set at 250 ° C. At this time, the opening of the T die was 0.5 mm, and the distance between the T die outlet and the pressure bonding point of the film of the cooling roll was set to 65 mm, and was pressed to the cooling roll of 250 mmφ. The temperature of the cooling roll was 120 ° C., the cooling roll 2 of 250 mmφ was provided on the downstream side, and the peeling roll of 250 mmφ was further provided on the downstream side. The temperature of each roll was 115 degreeC and 110 degreeC, and the film of 100 micrometer thickness was peeled from the peeling roll at the film surface temperature of 108 degreeC, and the norbornene-type resin film was obtained.
The norbornene-based resin film was bonded to a protective film while being pulled with a tension of 4 kgf to obtain an optical film roll having a length of 2000 m (hereinafter also referred to as “optical film roll (a-1)”). The bonding was performed by passing a transparent film and a protective film between a masking roll made of a mirror roll having a surface roughness of 0.1S and a rubber roll coated with 10 mm of a pair of urethane rubbers.
The protective film used at this time was a 30 μm-thick protective film (Tretech # 7332) manufactured by Toray Film, and the number of fish eyes in the protective film at this time was 0.5 / m ² . .
Further, the center line surface roughness of the protective film at this time was 0.0006 μm.
Protective film was 0.3 pieces / m ² was confirmed point defect number of the optical film after peeling.
The optical film roll (a-1) had a total light transmittance of 93% and a haze of 0.2%.

[Comparative Example 1]
In the same manner as in Example 1, the resin was melted to obtain a norbornene-based resin film, and then the protective film was bonded to the length of 2,000 m using the same mirror masking roll and rubber roll as in Example 1. An optical film roll (b-1) was obtained. The commercially available protective film used was a polyethylene film having a thickness of 30 μm, and the number of fish eyes was 6.5 / m ² . At this time, the center line surface roughness of the protective film was 0.008 μm.
When the number of point-like defects in the optical film after the protective film was peeled off was confirmed, it was 5.5 / m ² .
In addition, the optical film roll (b-1) had a total light transmittance of 93% and a haze of 0.3%.

[Comparative Example 2]
The resin was melted in the same manner as in Example 1 to obtain a norbornene-based resin film, and then a protective film was bonded in the same manner as in Example 1, while an optical film roll having a length of 2,000 m ( c-1) was obtained. The protective film used at this time was a commercially available polyethylene protective film having a thickness of 30 μm, and although the number of point-like defects was 5 / m ² , the surface was scratched. The surface roughness was 0.025 μm.
It was 4.5 pieces / m < ² > when the number of point-like defects of the optical film after peeling off the protective film was confirmed.
Further, the optical film roll (c-1) had a total light transmittance of 93% and a haze of 0.3%.
The results are shown in Table 1.

[Example 2]
Using the optical film roll (a-1) obtained in Example 1, after stretching 1.2 times using a roll nip type uniaxial stretching machine at 130 ° C., using a tenter type transverse stretching machine at 130 ° C. The optical film roll (a-2) stretched 1.4 times and having a thickness of 70 μm was obtained. Regarding the retardation of the optical film roll (a-2), the retardation (R0) in the film plane was 60 nm. The optical film roll (a-2) had a total light transmittance of 93% and a haze of 0.1%.
Further, when confirming the point-like defect number of the optical film roll (a-2), it was 0.1 pieces / ^{m 2.}

[Comparative Example 3]
Except having used an optical film roll (b-1), it carried out similarly to Example 2, and obtained the stretched optical film roll (b-2). As for the retardation of this film, the in-plane retardation (R0) was 63 nm. The total light transmittance was 93% and haze was 0.2%.
Furthermore, it was 3.5 piece / m < ² > when the number of the point-like defects of the said optical film roll (b-2) was confirmed.

[Example 3]
A polyvinyl alcohol film having a thickness of 50 μm was uniaxially stretched up to 4 times in about 5 minutes while being immersed in a 40 ° C. bath composed of 5 g of iodine, 250 g of potassium iodide, 10 g of boric acid, and 1,000 g of water to obtain a polarizing film. . The optical film roll (a-1) produced in Example 1 and the optical film roll (a-1) produced in Example 2 were used for the surface of this polarizing film using the water-based adhesive obtained in Adjustment Example 1. A polarizing plate (a) was obtained by continuously adhering one side of each to the polarizing film. The transmittance and polarization degree of this polarizing plate (a) were measured and found to be 43% and 99.99%, respectively. In addition, when the polarizing plate (a) is in a crossed Nicols state and irradiated with a backlight having a luminance of 10,000 cd from one side, light leakage due to point defects is completely confirmed even when observed from the other side. Was not.

[Comparative Example 4]
A polarizing plate (b) was obtained in the same manner as in Example 3 except that the optical film rolls (b-2) and (c-1) were used. The transmittance and polarization degree of this polarizing plate (b) were measured and found to be 42% and 99.87%, respectively. In addition, when the polarizing plate (b) is in a crossed Nicols state with the optical film roll (b-2) on the inner side and irradiated from one side with a backlight having a luminance of 10,000 cd, the other side is observed. As a result, 3.0 pieces / m ^{2 of} light leakage due to point defects were confirmed.

Even if the optical film roll formed by laminating and winding the optical film and the protective film of the present invention has a small amount of fish eyes in the protective film even when stored for a long period of time, minute irregularities may occur on the surface of the optical film. There is no optical unevenness. Therefore, the optical film obtained from the optical film roll of the present invention is, for example, a mobile phone, a digital information terminal, a pager, navigation, an in-vehicle liquid crystal display, a liquid crystal monitor, a liquid crystal television, a light control panel, a display for OA equipment, an AV equipment. It can be used for various liquid crystal display elements such as displays for display, electroluminescence display elements or touch panels. It is also useful as a wave plate used in an optical disk recording / reproducing apparatus such as a CD, CD-R, MD, MO, and DVD.

Claims (5)

An optical film roll obtained by laminating and winding an optical film made of a cyclic olefin resin and a protective film, wherein the number of fish eyes having a diameter of 30 μm or more in the protective film is 5 / m ² or less. The optical film roll according to claim 1, wherein the cyclic olefin-based resin is a (co) polymer of a compound represented by the following general formula (1).

(In Formula (1), R < ¹ > -R < ⁴ > is a hydrogen atom, a halogen atom, a C1-C30 hydrocarbon group, or another monovalent organic group, and may be the same or different. Further, any two of R ^{1 to} R ⁴ may be bonded to each other to form a monocyclic or polycyclic structure, m is 0 or a positive integer, and p is 0 or a positive integer. .)   The optical film roll according to claim 1 or 2, wherein the protective film has a center line average roughness Ra of 0.005 to 0.05 µm.   The optical film roll according to claim 1, wherein the protective film is made of a polyolefin-based resin. A method for producing an optical film roll, comprising: stacking and winding an optical film made of a cyclic olefin-based resin film and a protective film having a number of fish eyes having a diameter of 30 μm or more of 5 / m ² or less. .