JP2008207446A - Manufacturing method of optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an optical film having excellent film thickness uniformity and surface smoothness and little optical unevenness.
The present invention provides a method for producing an optical film, characterized in that a cyclic olefin resin and an antistatic agent are extruded from a die in a melt-mixed state and electrostatically pressed to a cooling roll to form a film.
[Selection figure] None

Description

  The present invention relates to a method for producing an optical film without a die line.

An optical film is required to be excellent in optical properties such as transparency, and it is important that the film is homogeneous and excellent in surface smoothness and has little optical unevenness. Therefore, when a film is formed by melt extrusion, it is called a die line by a manufacturing method (see Patent Documents 1 and 2) in which the film surface is electrostatically pressure-bonded to the cooling roll surface when the film is pressed onto the cooling roll after being extruded. A method of obtaining a film having excellent surface smoothness without streaky irregularities generated in the longitudinal direction of the film is used. However, when electrostatic pressure bonding is performed on a norbornene-based thermoplastic resin film, there is a problem that the film is difficult to be pressure-bonded unless a high voltage is applied, and the appearance of the film surface is impaired when a high voltage is applied.
JP-A-61-83017 JP 2001-192458 A

  This invention makes it a subject to provide the manufacturing method of an optical film which is excellent in film thickness uniformity and surface smoothness, and there is little optical nonuniformity.

  In the present invention, a cyclic olefin resin having a structural unit derived from a compound represented by the following formula (1) (hereinafter also referred to as “specific monomer”) and an antistatic agent are extruded from a die in a melt-mixed state. The present invention relates to a method for producing an optical film, wherein the film is formed by electrostatic pressure bonding to a cooling roll.

（式（１）中、Ｒ^１〜Ｒ^４は、水素原子、ハロゲン原子、炭素数１〜３０の炭化水素基、またはその他の１価の有機基であり、それぞれ同一または異なっていても良い。また、Ｒ^１〜Ｒ^４ のうち任意の２つが互いに結合して、単環または多環構造を形成しても良い。ｍは０または正の整数であり、ｐは０または正の整数である。）
帯電防止剤としては、アルキルベンゼンスルホン酸塩、ポリアミドオリゴマーおよびポリエチレングリコールから選ばれる少なくとも一種であることが好ましい。
本発明の製造方法においては、冷却ロールがフィルム圧着面の両端部に静電電極を有する構造であり、当該電極から２〜８ｋＶの電圧をかけて静電圧着することが好ましい。
本発明は、上記光学フィルムをさらに延伸してなる光学フィルムの製造方法であってもよい。

(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 antistatic agent is preferably at least one selected from alkylbenzene sulfonates, polyamide oligomers and polyethylene glycols.
In the manufacturing method of this invention, it is preferable that a cooling roll is a structure which has an electrostatic electrode in the both ends of a film crimping | compression-bonding surface, and the voltage of 2-8 kV is applied from the said electrode, and an electrostatic crimping is carried out.
The present invention may be a method for producing an optical film obtained by further stretching the optical film.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the optical film which is excellent in film thickness uniformity and surface smoothness, and there are few optical nonuniformities can be provided. Further, when the optical film is a stretched film, it can be suitably used as an optically uniform film having a stable retardation and optical axis.

Cyclic Olefin Resin The cyclic olefin resin used in the present invention is a resin having a structural unit derived from a specific monomer, and examples thereof include the following (co) polymers.
(1) A ring-opening (co) polymer of a specific monomer.
(2) A ring-opening copolymer of a specific monomer 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 a specific monomer and an unsaturated double bond-containing compound.
(6) Addition type (co) polymers of one or more monomers selected from specific monomers, vinyl cyclic hydrocarbon monomers and cyclopentadiene monomers, and their hydrogenated (co) weights Coalescence.
(7) An alternating copolymer of a specific monomer and an acrylate.
Of these, the hydrogenated (co) polymer of the ring-opening (co) polymer (3) which is excellent in both optical characteristics and processing characteristics is particularly preferably used.

<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 . ^{17, 10} ] -3-dodecene and the like.
These can be used alone or in combination of two or more.

Among the specific monomers, in the above formula (1), R ¹ and R ³ are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 2 carbon atoms. Each of R ² and R ⁴ is 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; An integer of 3 and 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 above formula (1), 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 preferably a methyl group. In particular, the fact that this alkyl group is bonded to the same carbon atom as that to which the specific polar group represented by the formula — (CH ₂ ) _n COOR is bonded is that of the obtained cyclic olefin-based resin. 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, more preferably 90% or more, and particularly preferably 99% 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, and when used as the wave plate of the present invention, 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 acids such as AlCl ₃ , BF ₃ , FeCl ₃ , Al ₂ O ₃ , HCl, CH ₂ 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.

Furthermore, as the vanadium compound, the 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 0.2 to 5 dl / g, more preferably 0.3 to 3 dl / g, particularly preferably 0.4 to 1.5 dl in terms of intrinsic viscosity [η] _inh. The polystyrene-reduced number average molecular weight (Mn) measured by gel permeation chromatography (GPC) after dissolving in tetrahydrofuran is 8,000 to 100,000, more preferably 10,000 to 80,000, Particularly preferred is 12,000 to 50,000, and the weight average molecular weight (Mw) is 20,000 to 300,000, more preferably 30,000 to 250,000, particularly preferably 40,000 to 200,000. A range is preferred. Moreover, molecular weight distribution (Mn / Mw) becomes like this. Preferably it is 2.0-4.0, More preferably, it is 2.5-3.7, More preferably, it is 2.8-3.5.
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, if Tg exceeds 350 ° C., the molding process becomes difficult, and it becomes necessary to increase the heating temperature during the molding process, so that there is a high possibility that the resin will deteriorate due to heat.

  The above cyclic olefin-based resins are not limited to the specific hydrocarbon-based resins described in, for example, JP-A-9-221577 and JP-A-10-287732 or publicly known, as long as the effects of the present invention are not impaired. These thermoplastic resins, thermoplastic elastomers, rubber polymers, organic fine particles, inorganic fine particles and the like may be blended.

  In addition, to the cyclic olefin resin used in the present invention, additives such as known antioxidants and ultraviolet absorbers are added for the purpose of improving the heat deterioration resistance and light resistance within a range not impairing the effects of the present invention. be able to. 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, and 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- By adding 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight, of an oxanilide compound such as ethyl-2′-ethoxyoxanilide to 100 parts by weight of the cyclic olefin resin, light resistance Can be improved.

Antistatic agent An antistatic agent is added for the purpose of preventing the deterioration of the external appearance of a film by performing electrostatic pressure bonding at a low voltage. Examples of the antistatic agent used in the present invention include a low molecular antistatic agent, a high molecular antistatic agent, a conductive filler, and the like, and the type is not particularly limited as long as it has an antistatic effect. In particular, those which are less prone to evaporation and sublimation are preferably used. These may be used alone or in combination of two or more.

Examples of the low molecular weight antistatic agent include glycerin esters such as glycerin monostearate, glycerin monobehenate, glycerin monopalmitate, and glycerin monolaurate; polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, Nonionic surfactants such as N, N-bis (2-hydroxyethyl) alkylamine, N-2-hydroxyethyl-N-2-hydroxyalkylamine, polyoxyethylene alkylamine, and fatty acid ester of polyoxyethylene alkylamine Anionic surfactants such as alkyl sulfonates, alkylbenzene sulfonates and alkyl phosphates; cationic surfactants such as tetraalkylammonium salts and tetraalkylbenzylammonium salts; Rukirubetain, amphoteric surfactants such as alkyl imidazolium betaine.
Examples of the polymer antistatic agent include polyether polymers such as polyethylene oxide, polyether ester amide, polyether amide imide, ethylene oxide / epichlorohydrin copolymer, methoxy polyethylene glycol (meth) acrylate copolymer; Examples include quaternary ammonium base-containing polymers such as quaternary ammonium salt-containing (meth) acrylate copolymers and quaternary ammonium base-containing maleimide copolymers; sulfonate-containing polymers such as polystyrene sulfonate.
Examples of the conductive filler include carbon such as carbon black and carbon nanotubes, metal particles such as nickel, copper, silver, and gold, and metal wires.

  Of these, sulfonate anionic surfactants are preferred because there is no deterioration in the appearance of the film due to the addition, and surface roughening, whitening, etc. in particular, and alkylbenzene sulfonate is particularly suitable for changes in the appearance of the film due to the addition. Is preferably used because of its small size.

Although the usage-amount of the said antistatic agent is not specifically limited, When the total amount of a resin component is 100 mass parts, Preferably it is 0.05-30 mass parts, More preferably, it is 0.1-25 mass parts, More preferably, it is 0. 0.1 to 20 parts by mass, particularly preferably 0.1 to 15 parts by mass. If the amount of the antistatic agent is less than 0.05 parts by mass, the antistatic effect is not sufficient and the charging voltage cannot be reduced, which is not preferable. If it exceeds 30 parts by mass, the appearance of the film may deteriorate due to bleeding on the surface of the film.
Such an antistatic agent may be added when pelletizing the cyclic olefin resin, or may be blended together with pellets of the cyclic olefin resin when melt-extruding.

Other Additives In the method for producing an optical film according to the present invention, an antioxidant may be added to prevent the resin from being thermally deteriorated due to the heat history during melt extrusion.
Specific examples of the antioxidant include 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 are mentioned, but the present invention is not limited to these, and these may be unsuitable depending on the Tg of the cyclic olefin resin to be melt-extruded. 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 is not preferable because there is a risk of causing die lines, fish eyes on the film, and burning.
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 Molding The optical film molding method of the present invention is characterized in that the above-mentioned cyclic olefin resin and antistatic agent are melt-mixed and extruded from a die and electrostatically pressed to a cooling roll to form a film. In particular, the cooling roll has a structure having electrostatic electrodes at both ends of the film pressure-bonding surface, and it is preferable to apply a voltage of 2 to 8 kV from the electrodes and perform electrostatic pressure-bonding.

In the melt extrusion method of the present invention, the resin is usually used for the purpose of removing moisture, gas (oxygen, etc.), residual solvent, etc. contained in the resin in advance before the resin pellets are put into the extruder. The resin is dried at an appropriate temperature not higher than Tg.
The dryer used for drying is not particularly limited. Usually, a hot air circulating dryer, a dehumidifying dryer, a vacuum dryer, an inert gas circulating dryer such as nitrogen is used, and the volatile component of the resin or In view of efficiently removing dissolved oxygen, it is particularly preferable to use an inert gas circulation dryer or a vacuum dryer. In order to suppress moisture absorption and oxygen absorption in the hopper, it is also preferable to seal the hopper with an inert gas such as nitrogen or argon, or to use a vacuum hopper that can be kept under reduced pressure. Furthermore, the extruder cylinder may be provided with a vent function to remove volatile components generated during melt extrusion and a function to seal with an inert gas such as nitrogen or argon in order to push the deterioration of the polymer due to oxygen contamination. preferable.

  It does not specifically limit as a method of obtaining a cyclic olefin resin film by a melt extrusion 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 and mixing the cyclic olefin-based resin and the antistatic agent, a method of mixing and melting the resin pellet and the antistatic agent with an extruder, a method of melting the pellet containing the resin and the antistatic agent, It is preferable to add the solution to the solution at the stage of synthesizing the resin and finish it simultaneously with the resin. After the molten mixture is quantitatively supplied by a gear pump and filtered through a metal filter or the like to remove impurities, a film shape is formed by a die. A method of extruding while forming is preferable.
As a method for cooling the film extruded from the die to form a sheet, it is preferable to use a sheet manufacturing apparatus called a single-sided belt type, particularly a sleeve type. 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. As a method for electrostatic pressure bonding, a method is used in which a charging electrode is disposed below the die discharge port so as to face the mirror roll, and electrostatic pressure bonding is applied from the charging electrode to both ends of the film. 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 film-like resin composition discharged from the discharge port is electrostatically pressure-bonded to the mirror roll by charging electrodes at both ends in the width direction, and is sandwiched between the mirror roll and the metal belt, and is applied to the mirror roll. After being transferred and cooled, it is peeled off by a peeling roll to form a film.
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. Also, the screw shape of the extruder is bent type, subflight type, tip dull mage type, full flight type, etc., with large compression ratio, small one, slow compression with long compression part length, short compression Although a compression type etc. are mentioned, the thing of the flight shape and compression type which can suppress melt | dissolution of oxygen and can suppress shear heat_generation | fever is preferable. A preferred compression ratio is 1.5 to 4.5, particularly preferably 1.8 to 3.6. 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 is formed of TiN, TiAlN, TiC, CrN, DLC (diamond-like carbon) by PVD (Physical Vapor Deposition) method, etc. Other ceramics sprayed or nitridized surfaces 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 of heating the roll is not particularly limited, but the roll temperature is preferably within the film-forming range and there is no temperature difference, and the allowable temperature difference in the width direction of the roll is preferably within 2 ° C, more preferably 1 ° C. Is within.
The charging electrode has 2 to 5 needles, and is preferably installed within 50 mm from both ends of the film and within 10 mm from the roll. If it is installed too far from both ends, the yield of the film deteriorates, which is not preferable.

  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.
The extruder cylinder is preferably sealed with an inert gas such as nitrogen or argon in order to prevent the resin composition from being oxidized and generating gel during melt extrusion.
The cyclic olefin resin and the antistatic agent melt-mixed by the extruder are 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 composition.
Thereafter, the extruded resin composition is electrostatically pressure-bonded to a mirror roll by charging electrodes at both ends or the entire surface in the width direction and cooled. And the sheet-like film is manufactured by peeling the resin composition transcribe | transferred on the mirror surface roll surface from the surface of a mirror surface roll with the roll for peeling.

  In the present invention, the processing temperature of the resin composition, that is, the set temperature of the extruder and the die is from the viewpoint that the molten resin composition with uniform fluidity can be discharged from the die and the deterioration can be suppressed. The resin is preferably Tg + 100 ° C. or higher and Tg + 200 ° C. or lower.

At this time, it is preferable to make the peripheral speed of the mirror roll and the metal belt close. 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.
Furthermore, as conditions at the time of film peeling, when setting it as peeling temperature _Tt (degreeC) and peeling stress _TF (MPa), the range of Tg-30 degreeC <= _Tt <= Tg + 5 degreeC, 0.01MPa < _TF <5MPa, respectively It is preferable that

Here, the temperature of the mirror roll which is a cooling roll is Tg-80-Tg + 10 degreeC normally, Preferably it is Tg-60-Tg-2 degreeC.
The horizontal part of the flow path of the die of the present invention hits the tip part of the outlet of the die, and this horizontal part of the tip is called a die land. The length of the die land is 10 to 50 mm, preferably 11 to 40 mm.

<Film stretching process>
The optical film of the present invention can be further stretched from the optical film obtained 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, Preferably, it 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 stretched film 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 is 10 times or more, 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 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.
The dimensional shrinkage ratio due to heating of the retardation 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, in addition to the selection of the monomers A and B which are the raw materials of the resin of the present invention, it is possible to control by the casting method and the stretching method.

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 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.

<Film characteristics>
The optical film (melt-extruded film, stretched film) of the present invention obtained as described above is characterized in that the thickness unevenness due to the die line on the film surface is small, preferably not. A die line is a flaw which the burnt resin adhering to the die exit attaches, resulting in a thickness unevenness in the longitudinal direction of the film. The optical film obtained by the present invention is characterized in that the die line height is 0.05 μm or less.
The optical film obtained by the production method of the present invention is preferably used for an optical film raw material in which optical quality is important because it has a small thickness unevenness and is easily obtained in the longitudinal direction. The range of preferable thickness unevenness is 2 μm or less per 1 m in the longitudinal direction, more preferably 1.5 μm or less, particularly preferably 1.0 μm or less, and most preferably 0.6 μm or less.

In addition, since the stretched optical film of the present invention is excellent in surface smoothness, the haze value at a thickness of 3 mm measured according to ASTM D1003 is 1% or less, preferably 0.8% or less.
Moreover, the average roughness Ra of the film obtained by the forming method is 0.010 μm or less, preferably 0.008 μm or less, and more preferably 0.007 μm or less.

≪Polarizing plate≫
The polarizing plate of the present invention is a water-based adhesive composed of an aqueous solution mainly composed of PVA resin, a polar group-containing adhesive, a photocuring agent on at least one surface of a polarizer composed of a PVA-based film. It can be manufactured by laminating using an adhesive, etc., heating or exposing as necessary, and pressing and adhering (laminating) the polarizer and the optical film.

≪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.

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, various evaluations were measured by the following methods.
[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.
[Die line and surface roughness]
The film was fixed vertically and a white screen was placed behind 500 mm. The light irradiated by the xenon lamp was transmitted through the film from a 45 ° oblique front of the film, and the position of the die line was specified from the image displayed on the screen.
About the said specific position of the film, the magnitude | size and average surface roughness of the die line of a film were calculated | required using the surface roughness meter (Kosaka Laboratory Ltd. CT-30K).
[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>
It consists of 94.8 parts of butyl acrylate, 5 parts of acrylic acid, and 0.2 part of 2-hydroxyethyl methacrylate, and has a weight average molecular weight (Mw) of 1,200,000, and a ratio of weight average molecular weight to number average molecular weight (Mn) (Mw / Mn ) Toluene was added to an ethyl acetate solution of 3.9 acrylic polymer to dilute to obtain a 13% toluene solution of the above acrylic polymer, and 2.0 parts of an isocyanate cross-linking agent [Coronate L (manufactured by Nippon Polyurethane)] was added. Then, the stirred solution was applied onto the release film and dried in two steps of 60 ° C. × 5 minutes and 100 ° C. × 5 minutes so as not to foam, and then a light release type release film was further applied to the adhesive surface. The laminate was temporarily fixed, and a non-support film having an adhesive thickness (average value) of 25 μm after drying was produced.

[Example 1]
As a resin, 100 parts by weight of a pellet of cyclic olefin resin (manufactured by JSR Corporation: trade name “ARTON D4531”, glass transition temperature 130 ° C.), 2.0 parts by weight of sodium dodecylbenzenesulfonate as an antistatic agent, oxygen concentration Leaded to an extruder (GM Engineering Co., Ltd .: GM-90) using 0.1 ppm of nitrogen 200 l / min, melted and mixed at 260 ° C., and sent in a fixed amount using a gear pump, and using a 5 μm leaf disk filter. The foreign matter was removed, and extrusion was carried out from a T die heated by an aluminum casting heater set at 250 ° C. Further, the opening of the T die at this time is 0.5 mm, the distance between the T die outlet and the pressure bonding point of the film of the cooling roll is 70 mm, and the surface of the cooling roll is 3 kV and 2.5 mA at both ends of the film. And pressure-bonded to a cooling roll of 250 mmφ. The temperature of the cooling roll was 120 ° C., a cooling roll 2 of 250 mmφ was provided on the downstream side, and a peeling roll of 250 mmφ was further provided on the downstream side. The temperature of each roll was set to 115 ° C. and 110 ° C., and a film having a film thickness of 100 μm was peeled from the peeling roll at a film surface temperature of 108 ° C. to obtain an optical film.
The height of the die line of the obtained optical film was 0.015 μm. Moreover, the surface roughness of the film was 0.004 μm. The optical film had a total light transmittance of 93% and a haze of 0.2%. Furthermore, the thickness nonuniformity in the film longitudinal direction was 0.76 μm.
[Example 2]
In Example 1 described above, an optical film was prepared in the same manner as in Example 1 except that potassium dodecylbenzenesulfonate was used in place of sodium dodecylbenzenesulfonate as the antistatic agent.
The height of the die line of the obtained optical film was 0.018 μm. Moreover, the surface roughness of the film was 0.004 μm. The optical film had a total light transmittance of 92% and a haze of 0.2%. Furthermore, the thickness nonuniformity in the film longitudinal direction was 0.68 μm.

[Comparative Example 1]
An optical film was obtained in the same manner as in Example 1 except that no antistatic agent was used.
The height of the die line of the obtained optical film was 0.055 μm. Moreover, the surface roughness of the film was 0.016 μm. The optical film had a total light transmittance of 93% and a haze of 0.5%. Furthermore, the thickness unevenness in the film longitudinal direction was 1.55 μm.
[Comparative Example 2]
An optical film was obtained in the same manner as in Example 1 except that the electrostatic pressure bonding was not performed.
The height of the die line of the obtained optical film was 0.085 μm. Moreover, the surface roughness of the film was 0.021 μm. The optical film had a total light transmittance of 93% and a haze of 0.4%. Furthermore, the thickness nonuniformity in the film longitudinal direction was 2.35 μm.

[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 1000 g of water to obtain a polarizing film. Using the pressure-sensitive adhesive obtained in Preparation Example 1 on the surface of this polarizing film, the optical film (a-1) prepared in Example 1 and the optical film (a-1) prepared in Example 2 were respectively polarizing films. The polarizing plate (a) was obtained by continuously adhering to each side. 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 from one side with a backlight having a luminance of 10000 cd, the stripe-like white color in the longitudinal direction of the film resulting from the die line is observed from the other side. There was no missing.

[Comparative Example 3]
A polarizing plate (b) was obtained in the same manner as in Example 3 except that the optical films (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. Also, when the polarizing plate (b) is placed in a two-crossed Nicol state with the optical film roll (b-2) on the inner side and is irradiated from one side with a backlight having a luminance of 10000 cd, when observed from the other side Two stripes of white discoloration in the longitudinal direction of the film due to the die line were observed.

  The optical film of the present invention has few die lines on the surface of the optical film and does not cause 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 (4)

It is characterized in that a cyclic olefin resin having a structural unit derived from the compound represented by the following formula (1) and an antistatic agent are extruded from a die in a melt-mixed state and electrostatically pressed to a cooling roll to form a film. A method for producing an optical film.

(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 method for producing an optical film according to claim 1, wherein the antistatic agent is at least one selected from alkylbenzene sulfonate, polyamide oligomer and polyethylene glycol. The method for producing an optical film according to claim 1, wherein the cooling roll has a structure having electrostatic electrodes at both ends of the film pressure-bonding surface, and is subjected to electrostatic pressure-bonding by applying a voltage of 2 to 8 kV from the electrode. . The method for producing an optical film according to claim 1, further comprising stretching.