KR20080072565A - Process for producing an optical film, optical film, retardation film and polarizing plate - Google Patents

Abstract

A method for producing an optical film is provided to produce the optical film which has no gel-like defects, shows good durability and excellent workability, and does not leave any sticky matter behind when the film is made. A method for producing an optical film includes a step of melt-extruding a composition comprising (a) 100 parts by weight of polymer having a structural unit represented by the following formula 1, (b) 0.1-4 parts by weight of an alkyl group-substituted phenol-based compound having a melting point in the range of a glass transition point(Tg) of the polymer-35 °C to Tg+75 °C, and (c) 0.1-4 parts by weight of a benzotriazole-based compound having a melting point in the range of the glass transition point of the polymer-35 °C to Tg+75 °C.

Description

Manufacturing method of optical film, optical film, retardation film and polarizing plate {PROCESS FOR PRODUCING AN OPTICAL FILM, OPTICAL FILM, RETARDATION FILM AND POLARIZING PLATE}

The present invention relates to a method for producing an optical film and an optical film for melt extrusion of a composition having excellent heat resistance by combining a specific antioxidant and a ultraviolet absorber in combination with a specific cyclic olefin polymer.

Conventionally, polymethyl methacrylate, polycarbonate, polystyrene, 3-methylpentene resin, etc. are known as transparent resin. These resins are industrially produced in large quantities, and are used in large quantities in various fields utilizing their good transparency. However, these resins are not necessarily sufficient in heat resistance, for example, even in the case of polycarbonate considered to be the most heat resistant resin among these resins, the glass transition temperature, which is an index of heat resistance, is about 150 ° C., which has higher heat resistance. Development is desired.

As a resin having excellent transparency and higher heat resistance, a ring-opening polymer of a norbornene derivative having a polar substituent has been proposed. However, since the ring-opening polymer of the norbornene derivative has a carbon-carbon double bond in its main chain, oxidation deterioration under high temperature is severe, and although it has a high glass transition temperature, it has not been put into practical use as a heat resistant polymer. For this reason, the attempt to improve the oxidative deterioration property by hydrogenating the said ring-opening polymer was proposed. The improvement of the oxidation deterioration property by hydrogenation can greatly improve the oxidation deterioration resistance compared with the conventional hydrogen-free polymer, but in the case of the high heat resistant resin having a high glass transition temperature, it is inevitably high There is a need for this, and deterioration at the time of processing, especially yellowing coloring, is still a problem.

For this reason, the following cyclic olefin thermoplastic resin composition which mix | blended the ultraviolet absorber and antioxidant with the cyclic olefin thermoplastic resin is proposed by following patent document 1 (WO99 / 38918). However, the optical film using a cyclic olefin thermoplastic resin needs to further improve weather resistance in order to prevent surface defects etc. by the deterioration of resin called a point defect to a high level. Therefore, in some cases, it is necessary to increase the ultraviolet absorber or the antioxidant, but if these additives are simply increased, the additive may sublimate or decompose in the film forming process and adhere to the film surface or the molding machine, or the additive in the film may bleed out. A problem arises in which a change over time occurs. Film surface adhesion or bleed out of the additives causes point defects derived from deposits or causes optical properties of the film to be degraded.

[Patent Document 1] WO99 / 38918

The present invention melt-extrudes a composition having excellent heat resistance by combining a specific cyclic olefin-based polymer with a combination of a specific antioxidant and an ultraviolet absorber, thereby freeing point defects, having good durability, and generating no deposit when forming a film. It is an object to provide an optical film having excellent properties.

The present invention is based on 100 parts by weight of a polymer having a structural unit represented by the following formula (1) (hereinafter also referred to as "polymer (1)" or "resin (1)"),

(2) 0.1 to 4 parts by weight of an alkyl group-substituted phenol compound (hereinafter also referred to as "Compound (2)") having a melting point in the range of the glass transition temperature (Tg) -35 ° C to Tg + 75 ° C of the polymer, and

(3) Melt-extruding a composition having a melting point of 0.1 to 4 parts by weight of a benzotriazole compound (hereinafter also referred to as "Compound (3)") in the range of the glass transition temperature (Tg) -35 ° C to Tg + 75 ° C of the polymer. It is related with the manufacturing method of the optical film characterized by the above-mentioned.

(In the formula 1, R ¹ to R ⁴ is a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or monovalent other organic group, and each may be the same or different, and any of R ¹ to R ⁴ Two of may combine with each other to form a monocyclic or polycyclic structure, m is 0 or a positive integer, p is 0 or a positive integer)

Here, it is preferable that the said compound (2) and the compound (3) are 20 weight% or less respectively in the thermal weight loss rate when hold | maintaining at 280 degreeC for 1 hour.

Moreover, in the manufacturing method of the optical film of this invention, it is preferable to carry out film-transferring on both sides of the melt of the said composition to a transfer roll.

Next, this invention relates to the optical film obtained by the manufacturing method of the said optical film.

Here, when the said optical film performs uniaxial stretching of the draw ratio 1.3-2.7 times at the temperature of Tg + 5 degreeC or more of the said polymer (1), the phase difference (Re) provided to the transmitted light of the stretched film obtained by following formula (1) It is desirable to satisfy.

[(Re / film thickness) / drawing ratio] ＞ 3.0 × 10 ^-3

(Re: retardation value expressed in nm, film thickness: nm)

Next, the present invention relates to a retardation film containing the optical film.

Next, this invention relates to the polarizing plate which used the said optical film as a protective film on at least one surface.

According to the present invention, by melt-extruding a composition having excellent heat resistance, which is a combination of a specific antioxidant and a ultraviolet absorber in combination with a specific cyclic olefin polymer, there is no point defect, good durability, and no deposits at the time of film formation. The optical film excellent in workability is obtained.

Polymer (1)

As a polymer (1) used for the optical film of this invention, the following (co) polymer is mentioned.

(A) The (co) polymer which hydrogenated the ring-opening (co) polymer of the specific monomer represented by following General formula (2).

(B) The copolymer which hydrogenated the ring-opening copolymer of the specific monomer represented by following formula (2) and a copolymerizable monomer.

(In Formula 2, R ^{1 To} R ⁴ , m, p are the same as in Formula 1)

<Specific monomer>

Although the following compounds are mentioned as a specific example of the said specific monomer, This 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 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-phenyl-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3- dodecene,

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4. 4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene,

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

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

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

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

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

Etc. can be mentioned.

These can be used individually by 1 type or in combination of 2 or more types.

Among the specific monomers, R ¹ and R ^{3 in} the general formula (2) are hydrogen atoms or hydrocarbon groups having 1 to 10 carbon atoms, more preferably 1 to 4, particularly preferably 1 to 2, and R ² and R ⁴ are A hydrogen atom or a monovalent organic group, at least one of R ² and R ⁴ represents a polar group having a polarity other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, p is an integer of 0 to 3, and Preferably it is m + p = 0-4, More preferably, it is 0-2, Especially preferably, m = 1, p = 0. The specific monomer of m = 1 and p = 0 is preferable at the point which is excellent in mechanical strength, while the glass transition temperature of the polymer (1) obtained is high.

As a polar group of the said specific monomer, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, a cyano group, etc. are mentioned, These polar groups can be couple | bonded through coupling groups, such as a methylene group. Moreover, the hydrocarbon group etc. which the bivalent organic group which has polarity, such as a carbonyl group, an ether group, a silyl ether group, a thioether group, and an imino group, couple | bond and couple | bond are mentioned as a polar group. In these, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or allyloxycarbonyl group is especially preferable.

In addition, R ² and R one or more of the ^4, the formula - (CH ₂₎ a polar group of monomers represented by _n COOR is, the obtained polymer (1) which has excellent adhesion to the high glass transition temperature and low moisture absorption, a variety of materials It is preferable at the point. In the formula according 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 carbon atoms, preferably an alkyl group. In addition, n is usually 0 to 5, but the smaller the value of n, the lower the glass transition temperature of the obtained polymer (1) is preferable in terms of heat resistance, and the specific monomer having n of 0 is easy to synthesize. It is preferable at one point.

In Formula 2, R ¹ or R ³ is preferably an alkyl group, preferably an alkyl group of 1 to 4 carbon atoms, more preferably an alkyl group of 1 to 2, particularly a methyl group, and particularly, the alkyl group is the formula - (CH ₂₎ that there is a specific polar group represented by COOR _n is bound to the same carbon atom and the binding carbon atom, is preferred in that it is possible to lower the hygroscopicity of the resulting polymer (1).

<Copolymerizable monomer>

Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and dicyclopentadiene.

As carbon number of cycloolefin, 4-20 are preferable and 5-12 are more preferable. These can be used individually by 1 type or in combination of 2 or more types.

The preferred use range of the specific monomer / copolymerizable monomer is 100/0 to 50/50 by weight, more preferably 100/0 to 60/40.

<Opening polymerization catalyst>

In the present invention, the ring-opening polymerization reaction for obtaining the ring-opening (co) polymer of the (A) specific monomer and the ring-opening copolymer of the (B) specific monomer and the copolymerizable monomer is carried out in the presence of a metathesis catalyst.

This metathesis catalyst comprises (a) at least one selected from W, Mo, and Re, (b) Deming's periodic table of Group IA elements (e.g., Li, Na, K, etc.), Group IIA elements (e.g., , Mg, Ca, etc.), group IIB elements (e.g., Zn, Cd, Hg, etc.), group IIIA elements (e.g., B, Al, etc.), group IVA elements (e.g., Si, Sn, Pb Etc.), or a compound of a group IVB element (e.g., Ti, Zr, etc.), and a catalyst including a combination with one or more selected from those having one or more of the above element-carbon bonds or the above element-hydrogen bonds. In this case, in order to increase the activity of the catalyst, the (c) additive described later may be added.

As a representative example of a compound of W, Mo, or Re suitable as the component (a), Japanese Patent Laid-Open No. 1-32626 such as WCl ₆ , MoCl ₆ , ReOCl _3, etc. The compound described in the 17th line of upper right column is mentioned.

Specific examples of the component (b) include nC ₄ H ₉ Li, (C ₂ H ₅ ) ₃ Al, (C ₂ H ₅ ) ₂ AlCl, (C ₂ H ₅ ) _1.5 AlCl _1.5 , (C ₂ H ₅ ) AlCl ₂ And the compound described in Japanese Patent Laid-Open Publication No. Hei 1 32626, page 8, upper right column 18th to page 8, lower right column 3, such as methylalumoxane and LiH.

As representative examples of the component (c), which is an additive, alcohols, aldehydes, ketones, amines, and the like can be preferably used. The left top column can use the compounds disclosed in line 17.

As the usage-amount of a metathesis catalyst, the "(a) component: specific monomer" is a range which is usually 1: 500-1: 50,000 in the molar ratio of the said (a) component and a specific monomer, Preferably it becomes 1: 1,000-1: 10,000. Range.

The ratio of the component (a) and the component (b) is in the range of 1: 1 to 1:50, preferably 1: 2 to 1:30, in terms of metal atomic ratio.

The ratio of the component (a) and the component (c) is in the molar ratio of (c) :( a) in the range of 0.005: 1 to 15: 1, preferably 0.05: 1 to 7: 1.

<Solvent for Polymerization Reaction>

As a solvent (solvent constituting a molecular weight regulator solution, a solvent of a specific monomer and / or metathesis catalyst) used in the ring-opening polymerization reaction, for example, alkanes such as pentane, hexane, heptane, octane, nonane, decane, cyclohexane, Cycloalkanes such as cycloheptane, cyclooctane, decalin, norbornane, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, chlorobutane, bromohexane, methylene chloride, dichloroethane, hexamethylenedibromide, Halogenated alkanes such as chlorobenzene, chloroform and tetrachloroethylene, compounds such as aryl halide, saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, iso-butyl acetate and methyl propionate, dibutyl ether and tetrahydrofuran And ethers such as dimethoxyethane and the like, and these may be used alone or in combination. Of these, aromatic hydrocarbons are preferred.

As a usage-amount of a solvent, "a solvent: specific monomer (weight ratio)" is the quantity which is usually 1: 1-10: 1, Preferably it is the quantity which becomes 1: 1-5: 1.

<Molecular weight regulator>

Although molecular weight control of the ring-opening (co) polymer obtained can be performed also according to polymerization temperature, the kind of catalyst, and the kind of solvent, in this invention, it adjusts by coexisting a molecular weight modifier in a reaction system.

Here, as a preferable molecular weight modifier, alpha olefins and styrene, such as ethylene, a propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, etc. Among these, 1-butene and 1-hexene are especially preferable.

These molecular weight modifiers can be used individually or in mixture of 2 or more types.

As a usage-amount of a molecular weight modifier, it becomes 0.005 to 0.6 mol, Preferably it is 0.02 to 0.5 mol with respect to 1 mol of specific monomers provided for a ring-opening polymerization reaction.

(B) In order to obtain a ring-opening copolymer, although a specific monomer and a copolymerizable monomer can be ring-opened-copolymerized in a ring-opening polymerization process, conjugated diene compounds, such as polybutadiene and polyisoprene, styrene-butadiene copolymer, and ethylene-non-porous A specific monomer may also be ring-opened polymerized in the presence of an unsaturated hydrocarbon-based polymer including two or more carbon-carbon double bonds in a main chain such as a liquid diene copolymer or polynorbornene.

The ring-opening (co) polymer obtained as mentioned above is further hydrogenated, and the polymer (1) suitable for the optical use used for this invention is obtained.

<Hydrogenated Catalyst>

The hydrogenation reaction is a conventional method, i.e., a hydrogenation catalyst is added to a solution of a ring-opening (co) polymer, and hydrogen gas at atmospheric pressure to 300 atm, preferably 3 to 200 atm is preferably 0 to 200 캜, preferably It is performed by acting at 20-180 degreeC.

As a hydrogenation catalyst, what is used for the hydrogenation reaction of a normal olefinic compound can be used. As this hydrogenation catalyst, a heterogeneous catalyst and a homogeneous catalyst are mentioned.

As a heterogeneous catalyst, the solid catalyst which carried noble metal catalyst substances, such as palladium, platinum, nickel, rhodium, ruthenium, on support | carriers, such as carbon, a silica, alumina, titania, is mentioned. As the homogeneous catalyst, nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octate / 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 hydrogenated catalysts are used in a ratio such that the ring-opening (co) polymer: hydrogenated catalyst (weight ratio) is 1: 1 × 10 ⁻⁶ to 1: 2.

Thus, the polymer (1) obtained by hydrogenation has the outstanding thermal stability, and does not deteriorate the characteristic also by the heating at the time of shaping | molding process or the use as a product. Here, hydrogenation rate is 50% or more normally, Preferably it is 70% or more, More preferably, it is 90% or more.

In addition, the hydrogenation rate of the polymer (1) is 50% or more, preferably 90% or more, more preferably 98% or more, particularly preferably 99% or more, as measured by 500 MHz and ¹ H-NMR. Preferably it is 99.5% or more. The higher the hydrogenation rate, the better the stability against heat and light.

On the other hand, it is preferable that the gel content contained in the said polymer (1) is 5 weight% or less, and, as for the polymer (1) used for this invention, it is especially preferable that it is 1 weight% or less.

The glass transition temperature (Tg) of the polymer (1) thus obtained is usually 100 ° C to 250 ° C, preferably 110 ° C to 200 ° C, more preferably 120 ° C to 180 ° C. When Tg is less than 100 ° C, heat deformation resistance may be insufficient. On the other hand, when Tg exceeds 250 ° C, it is necessary to melt-extrude at very high temperatures, and under such conditions, the resin is thermally deteriorated during melt extrusion, and mechanical The property may be degraded, or foreign substances such as discoloration, gel, etc. may be generated on the surface or inside thereof, resulting in a decrease in surface uniformity or coloring, making it difficult to manufacture a high quality film.

On the other hand, the glass transition temperature of the polymer (1) can be easily adjusted by the method of copolymerizing with a copolymerizable monomer and using the specific monomer which differs in structure.

In addition, the intrinsic viscosity (η _inh ) at 30 ° C. measured by a Ubbelohde viscometer using a chloroform solution of the polymer (1) is usually 0.35 to 2.0 dl / g, preferably 0.4 to 1.5 dl / g, more Preferably it is 0.45-1.0 dl / g.

In addition, the polystyrene reduced number average molecular weight (Mn) measured by gel permeation chromatography (GPC: tetrahydrofuran solvent) is usually 1,000 to 500,000, preferably 2,000 to 300,000, and more preferably 5,000 to 300,000. The weight average molecular weight (Mw) is usually 5,000 to 2 million, preferably 10,000 to 1 million, more preferably 30,000 to 500,000.

When the intrinsic viscosity (η _inh ) is less than 0.35 dl / g, when the number average molecular weight (Mn) is less than 1,000 or when the weight average molecular weight (Mw) is less than 5,000, the polymer (1) has a significantly low strength. Can be. On the other hand, when the intrinsic viscosity (η _inh ) exceeds 2.0 dl / g, when the number average molecular weight (Mn) exceeds 500,000 or when the weight average molecular weight (Mw) exceeds 2 million, the polymer (1 ), The melt viscosity becomes too high, making it difficult to remove foreign substances by the polymer filter, or it is difficult to obtain a high quality film suitable for optics due to deterioration of the resin due to shear heat generation, thermal deterioration due to high temperature processing, and the like. Can be done.

Alkyl-substituted phenolic compounds (2006.01)

Next, the alkyl-substituted phenol compound (2) used in the present invention is a stable form of the active species by reacting with an active radical which is caused by the prevention of deterioration of the polymer (1), heat or ultraviolet rays, and the deterioration of the polymer. To prevent degradation of the polymer.

Melting | fusing point of an alkyl substituted phenol type compound (2) is glass transition temperature (Tg) -35 degreeC-Tg + 75 degreeC of polymer (1), Preferably it is Tg-30 degreeC-Tg + 70 degreeC. If the temperature is lower than Tg-35 占 폚, the vapor pressure of the compound is increased to increase the volatility, so that the compound itself, decomposition products due to heat and oxygen during manufacture and processing are generated, and adhere to a cooling (casting) roll or a film. There is. On the other hand, when it is higher than Tg + 75 ° C, the compound having increased fluidity due to high heat during manufacture and processing is bleeded to the surface of the resin composition, and because of its high melting point in the molding cooling process, it cannot be used because of its high melting point. there is a problem.

On the other hand, the alkyl-substituted phenolic compound (2) has a thermal weight reduction rate when the compound is maintained at 280 ° C for 1 hour, preferably 20% by weight or less, more preferably 10% by weight or less. If it exceeds 20% by weight, the amount of volatiles at the time of heat treatment and the side products which may be generated by thermal decomposition may increase, such as in the production of the film of the present invention. It is not preferable because there is a risk of attachment.

The above alkyl group-substituted phenolic compound (2) is represented by, for example, the following formula (3).

In formula (3), R ⁵ represents an avalent organic group having one or more ester bonds, amide bonds or ether bonds, R ⁶ and R ⁷ each independently represent an alkyl group, and a plurality of R ⁶ and R ⁷ are each May be the same or different and a represents an integer from 2 to 4)

In said Formula (3), as an organic group of R <^5> , Preferably, group represented by following formula (3a) is mentioned.

(In formula (3a), R <^8> represents the hydrocarbon group remove | excluding a hydrogen atom from a hydrocarbon; or the heterocyclic containing organic group remove | excluding a hydrogen atom from a heterocyclic containing compound, A is -COO-, -OCO-, -O -, At least one bonding group selected from -CONH- and -NHCO-, R ⁹ represents a monovalent hydrocarbon group or a heterocyclic containing organic group)

In formula (3a), as R ⁸

Alkanes having 1 to 10 carbon atoms such as methane, ethane, propane, i-propane, n-butane, i-butane, t-butane, n-heptane and n-hexane;

Cycloalkanes having 3 to 10 carbon atoms such as cyclopentane, cyclohexane, and cyclooctane;

Aromatic hydrocarbons having 6 to 20 carbon atoms, such as benzene, naphthalene, bisphenol, anthracene and toluene;

A hydrocarbon group obtained by removing a hydrogen atom from a hydrocarbon compound such as

Heterocyclic-containing organic groups having a hydrogen atom removed from heterocyclic-containing compounds such as pyrrolidine, piperidine, imidazolidine, piperazine, morpholine, pyrrole, imidazole, pyridine, pyrazine and pyrimidine Can be.

Further examples of the formula (3a), R ⁹ Examples of the hydrocarbon group in which one hydrogen atom has been removed from the hydrocarbon compound or heterocyclic ring-containing compound containing an organic group or a hetero ring.

Specific examples of the alkyl-substituted phenolic compound (2) include pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1- [2- [3 -3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] 2,2,6,6-tetramethylpiperidine, 3,9-bis [2- {3 (3-t-butyl-4-hydroxy5-methylphenyl) propionyloxy} -1,1-dimethylethyl ] -2,4,8,10-tetraoxaspiro [5.5] undecane, bis- [3,3-bis- (4'-hydroxy-3'-t-butylphenyl) butanoic acid] glycol esters and the like Among these, the compound which has melting | fusing point of glass transition temperature (Tg) -35 degreeC-Tg + 75 degreeC of the polymer (1) used among these is selected and used.

These alkyl group substituted phenol type compounds (2) can be used individually by 1 type or in combination of 2 or more types.

The amount of the alkyl group-substituted phenol compound (2) added is 0.1 to 4 parts by weight, preferably 0.2 to 3 parts by weight based on 100 parts by weight of the polymer (1). If the amount is less than 0.1 part by weight, there is a problem that the quality of the processed product is deteriorated, such as being colored at the time of manufacturing the composition or during processing such as film forming, or generating a large number of point defects in the film by gelation. On the other hand, when it exceeds 4 weight part, there exists a problem that the color of a film deteriorates under the influence of the coloring by the quinone which resulted from deterioration of a compound, or the compound itself and a decomposition product adhere easily by bleed from a composition.

Benzotriazole  Compound (3)

The benzotriazole-based compound (3) suppresses the generation of active radical species that cause deterioration of the polymer (1) by absorbing ultraviolet rays. The benzotriazole-based compound (3) exhibits an effect mainly when using an optical film formed into a film and is colored due to deterioration. It also acts to prevent degradation of transparency.

Melting | fusing point of a benzotriazole type compound (3) is the glass transition temperature (Tg) -35 degreeC-Tg + 75 degreeC of polymer (1) similarly to compound (2), Preferably it is Tg-30 degreeC-Tg + 70 degreeC. If the temperature is lower than Tg-35 占 폚, the vapor pressure of the compound increases and the volatility increases, causing decomposition of the compound itself, heat and oxygen during manufacture and processing, and sticking to a cooling (casting) roll or a film. have. On the other hand, if it is higher than Tg + 75 ° C., the compound that has increased fluidity due to high heat during manufacture and processing is bleeded to the surface of the composition, and because of its high melting point in the molding cooling process, it cannot be used because of its high melting point. There is.

On the other hand, the benzotriazole compound (3) has a thermal weight reduction rate when the compound is held at 280 ° C. for 1 hour, like the alkyl group-substituted phenol compound (2), preferably 20% by weight or less, more preferably It is 10 weight% or less. When it exceeds 20% by weight, there is a fear that the amount of volatiles and the by-products that may be generated by thermal decomposition may increase when the film is processed according to the present invention. It is not preferable because there is a risk of attachment.

Specific examples of the benzotriazole-based compound (3) include 2,2'-methylenebis [4- [1,1,3,3-tetramethylbutyl] -6- (2H-benzotriazol-2-yl) phenol] , 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- [2'-hydroxy-3 ', 5'-bis- (α, α-dimethylbenzyl) phenyl ] -2H-benzotriazole, 2- [2'-hydroxy-3 '-(1-methyl-1-phenylethyl) -5'-(1,1,3,3-tetramethylbutyl) -benzotria A sol etc. are mentioned, These can be used individually by 1 type or in combination of 2 or more types.

The amount of the benzotriazole compound (3) added is 0.1 to 4 parts by weight, preferably 0.2 to 3 parts by weight based on 100 parts by weight of the polymer (1). If the amount is less than 0.1 part by weight, there is a problem that the addition effect may not be observed. On the other hand, if the amount is more than 4 parts by weight, the influence of the absorption wavelength of the light of the compound is increased, which is indispensable in the quality of the optical film formed. There is also a problem of lowering the light transmittance.

OTHER ADDITIVES

On the other hand, in this invention, additives other than the said essential (2)-(3) components, such as a lubricant, another ultraviolet absorber, dye, or a pigment, can be used in the range which does not impair the effect of this invention. Of course, also in this case, in the case of the additive which has a melting point, it is preferable that the melting point exists in the melting | fusing point range of the essential (2)-(3) component of this invention.

Manufacturing method of optical film

Hereinafter, although the specific example is given and demonstrated about equipment, such as an extruder used by this invention, this invention is not limited to these specific examples.

In the melt-extrusion method in the present invention, before the polymer (1) (and the components (2) to (3)) is introduced into the extruder, water, gas (oxygen, etc.) and residual solvent contained in the polymer are usually contained. The resin is dried at an appropriate temperature of Tg or less for the purpose of removing the back in advance.

Although the dryer used for drying is not specifically limited, Usually, inert gas circulation dryers, such as a hot air circulation dryer, a dehumidification dryer, a vacuum dryer, and nitrogen, are used, and the volatile component or dissolved oxygen of the polymer (1) can be efficiently omitted. In particular, it is preferable to use an inert gas circulation type dryer or a vacuum dryer. Moreover, in order to suppress moisture absorption and oxygen absorption in a hopper, it is also preferable to use the vacuum hopper which can seal a hopper with inert gas, such as nitrogen and argon, or can keep it at reduced pressure. Moreover, it is preferable to provide the extruder cylinder with the function of sealing with inert gas, such as nitrogen and argon, in order to remove the volatile component generate | occur | produced during melt-extrusion, and to suppress deterioration of a polymer by a vent function or oxygen mixing.

In the extrusion molding method, the resin is melted by an extruder, quantitatively supplied by a gear pump, the impurities are removed by filtration by a metal filter, shaped into a film by a die, and the film is cooled by using a take-off machine, The winding method using a winder is generally used.

As an extruder used for extrusion molding, all of a single screw, a twin screw, a planetary type, a co-kneader, a Benbury mixer type, etc. can be used, Preferably, a single screw extruder is used.

As the screw shape of the extruder, there are a vent type, a tip less-magnet type, a double flight type, a full flight type, and the like, and the compression type is a slow compression type, a rapid compression type, etc., but a full flight type slow compression type is preferable. .

Regarding the gear pump used for metering, there are an internal lubrication method in which the resin returned from the downstream side between the gears enters the system and an external lubrication method discharged to the outside, but an external lubrication method that is hardly subject to heat history is preferable. The cutting direction of the gear value of the gear pump is more preferable in terms of stabilization of metering than in the direction parallel to the axis.

Regarding the filter used for the filtration of foreign matter, a leaf disc type, a candle filter type, a leaf type, a screen mesh, etc. may be mentioned, but a leaf disc type having a relatively small residence time distribution and capable of increasing the filtration area is preferable. . Examples of the filter element include metal fiber sintering type, metal powder sintering type, metal fiber / powder lamination type and the like.

Examples of the center pole shape of the filter include an outflow type, a hexagonal column inner flow type, a circumferential inner flow type, and the like, but any shape may be selected as long as the retention portion is small, but is preferably an outflow type.

The molten polymer (1) (and (2) to (3) components) is discharged from the die, solidified in tight contact with a cooling drum, and formed into a desired film. Regarding the die shape, it is necessary to make the resin flow inside the die uniform, and in order to maintain film uniformity in the die, it is essential that the pressure distribution inside the die near the die outlet is constant in the width direction. In addition, the flow rate of resin in the width direction is substantially constant, and it is essential in order to obtain thickness uniformity that it is constant in the range which can adjust the fine adjustment of the flow volume in a die exit by a lip opening degree. In order to satisfy the above conditions, the manifold shape is preferably a coat hanger type, and the straight manifold, fish tail type and the like are not preferable because a flow rate distribution in the width direction tends to occur.

In addition, in order to make the thickness distribution of the film uniform, it is important to make the temperature distribution at the die outlet constant in the width direction, and the temperature distribution is preferably ± 1 ° C or less, more preferably ± 0.5 ° C or less. . When temperature nonuniformity arises in the width direction exceeding +/- 1 degreeC, melt viscosity difference of resin arises, thickness nonuniformity, stress distribution nonuniformity, etc. generate | occur | produce, and phase difference nonuniformity arises easily in the process of extending | stretching operation, and is unpreferable. .

In addition, the lip opening amount (hereinafter referred to as "lip gap") of the die outlet is usually 0.05 to 1 mm, preferably 0.3 to 0.8 mm, more preferably 0.35 to 0.7 mm. If the lip gap is less than 0.05 mm, it is not preferable because the resin pressure inside the die becomes too high and the resin tends to cause resin leakage from places other than the lip of the die. On the other hand, when a lip gap exceeds 1 mm, since the resin pressure of a die becomes difficult to rise, the thickness uniformity of the width direction of a film worsens and it is unpreferable.

Examples of the method for tightly solidifying the film extruded from the die include a nip roll method, an electrostatic application method, an air knife method, a vacuum chamber method, a calendar method, and the like, and an appropriate method is selected according to the thickness of the film and the application.

It is preferable that various surface treatments are performed also on the cooling roll surface for solidifying the film extruded from the die like the extruder cylinder, the inner surface of the die, and the like. These surface treatments prevent the adhesion of the extruded film to the roll surface to prevent film thickness irregularities, increase the surface precision of the cooling roll, and have high surface hardness, thus making it difficult to cause scratches and the like. Even if it does, it is preferable at the point which can manufacture the film without thickness nonuniformity, maintaining the film surface precision stably.

On the other hand, when solidifying the melt melt-extruded from the die, if the film is double-sided transfer and film forming, such as by using a double-side transfer type device called a sleeve touch type, a cooling belt capable of elastic deformation on the opposite side of the first cooling roll with respect to the melt. In addition, it has the effect of improving the surface smoothness of the film and at the same time, because the film is in contact with the surface, the molecular orientation during take-up is reduced, which can produce a film with less die line or optical deformation which is considered a problem in the melt-extruded film. It is preferable at the point. In addition, in manufacture of the film of the resin composition which mix | blended the said component (2), (3) and the other additive as needed, since the temperature change of the film surface is gentle, volatiles etc. of an additive are ubiquitous, and it is hard to solidify cooling, It is also preferable at the point which deposits to a dyna roll or a film are suppressed.

Examples of the material of the extruder (cylinder screw, etc.) and the die include stainless steel such as SCM-based steel and SUS, but are not limited thereto. In addition, the extruder cylinder, the inner surface of the die, and the extruder screw surface are plated with chromium, nickel, titanium, etc., and TiN, TiAlN, TiCN, CrN, DLC (diamond-like carbon) by PVD (Physical Vapor Deposition) method, etc. It is preferable to use a film having a film formed thereon, a tungsten-based material such as WC, or a ceramic such as a summit sprayed, or a nitrided surface thereof. Since such a surface treatment has a small friction coefficient with resin, it is preferable at the point from which the molten state of uniform resin is obtained.

Resin temperature (extruder cylinder temperature) at the time of manufacturing the optical film of this invention is 200-350 degreeC normally, Preferably it is 220-320 degreeC. If the resin temperature is less than 200 ° C, the resin cannot be melted uniformly, while if it exceeds 350 ° C, the resin is thermally deteriorated at the time of melting, making it difficult to manufacture a high quality film having excellent surface properties. Moreover, it is especially preferable to exist in the said temperature range and to be the temperature within the range of Tg + 120 degreeC-Tg + 160 degreeC with respect to the glass transition temperature (Tg) of resin. For example, when Tg of resin is 130 degreeC, especially preferable temperature range is 250 degreeC-290 degreeC in film manufacture.

The shear rate during melt extrusion is usually 1 to 500 (1 / sec), preferably 2 to 350 (1 / sec), more preferably 5 to 200 (1 / sec). If the shear rate at the time of extrusion is less than 1 (1 / sec), the resin composition cannot be melted uniformly, so that an extruded film with a small thickness nonuniformity cannot be obtained, while if it exceeds 500 (1 / sec), the shear force is too high. It may become large, decompose | disassemble and deteriorate a resin composition and an additive, and defects, such as foaming, a die line, and a deposit, may arise on the surface of an extruded film.

The thickness of the optical film of this invention is 10-800 micrometers normally, Preferably it is 20-500 micrometers, More preferably, it is 40-500 micrometers. In the case of thickness less than 10 μm, there may be difficulty in post-processing such as stretching due to lack of mechanical strength or the like, while in the case of thickness exceeding 800 μm, a film having a uniform thickness or surface property may be produced. Not only is it difficult, it can become difficult to wind up the obtained film.

The thickness distribution of the optical film of the present invention is usually within ± 5%, preferably within ± 3%, and more preferably within ± 1% with respect to the average value. When thickness distribution exceeds +/- 5%, retardation nonuniformity may become easy to occur when extending | stretching process is used as retardation film.

Moreover, it is preferable that the thermal weight reduction rate at the time of heating at 260 degreeC for 1 hour in the optical film of this invention is 2 weight% or less, Preferably it is 1 weight% or less. If the said thermal weight loss rate is 2 weight% or less, it is preferable at the point that there is little volatile matter, there is no generation | occurrence | production of a deposit at the time of film forming, and it is excellent in weatherability.

Phase difference  film

The processing conditions for obtaining the retardation film of this invention are shown below.

The stretching temperature is usually Tg ± 20 ° C, preferably Tg ± 15 ° C, and more preferably Tg + 5 to Tg + 15 ° C based on the Tg of the polymer (1) contained in the melt-extruded film of the present invention.

The stretching ratio is appropriately selected according to the desired phase difference value, and depends on whether it is uniaxial stretching or biaxial stretching, but in the case of uniaxial stretching, it is usually 1.01 to 5 times, preferably 1.1 to 3 times, more preferably 1.3 To 2.7 times.

In addition, when the fusion extrusion film of this invention is uniaxially stretched on condition that extending | stretching temperature becomes Tg + 5 degreeC or more, for example, Tg + 10 degreeC and draw ratio of 1.3-2.7 times of the polymer (1) contained in the said melt extrusion film, It is preferable to satisfy the relationship represented by the following formula (1).

<Equation 1>

[(Re / film thickness) / drawing ratio] ＞ 3.0 × 10 ^-3

(Re: retardation value expressed in nm, film thickness: nm)

Here, Tg is the value of Tig (external glass transition start temperature) calculated | required by DSC (differential scanning calorimetry) at the temperature increase rate of 10 degree-C / min according to JISK7121.

In addition, the above-mentioned uniaxial stretching method for checking the phase difference expression property at the time of stretching processing of a melt-extruded film is 400% / min in the strain rate at the time of extending | stretching, and is film both ends substantially in the direction perpendicular | vertical to a extending | stretching direction. Indicates the case where it is not fixed.

When the melt-extruded film satisfies the relationship represented by the above formula, it is easy to obtain a retardation film having a desired retardation in high yield by stretching. On the other hand, when the relationship expressed by the above equation is not satisfied, it may be difficult to obtain a desired phase difference, and the film surface may be whitened, resulting in a problem that the in-plane deviation of the phase difference becomes large.

In the case of a film obtained by melt extrusion of the polymer (1) without using the essential components (the above (2) to (3) components) of the present invention, the above relationship is often not satisfied, and the melt extrusion film is stretched. In order to obtain a desired retardation value, in particular, a retardation value of 250 nm or more, in a thickness of 20 to 100 µm, strict stretching conditions are often required and often difficult.

On the other hand, in the case of the melt-extruded film obtained by using the components (2) to (3) which are essential components of the present invention, the above relationship is often satisfied, and when the melt-extruded film satisfying the above relationship is used, it is 250 nm to A phase difference film having a thickness of 20 to 100 µm having a phase difference value of 500 nm can be easily obtained.

On the other hand, λ / 2 at 550 nm which is generally used as a reference wavelength in the technology related to liquid crystal displays is 275 nm, and it is well known that a retardation film having such a phase difference is very useful as a so-called "λ / 2" plate.

Polarizer

The polarizing plate of this invention is the water-based adhesive agent, polar group containing adhesive agent, and light which contain the aqueous solution which mainly made PVA resin the optical film of this invention obtained by the above on at least one surface of the polarizer containing a PVA system film etc. It can be manufactured by bonding using a curable adhesive, etc., heating or exposing this as needed, and crimping | bonding and bonding (laminating) a polarizer and an optical film.

<Example>

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded. In addition, "part" and "%" are basis of weights unless there is particular notice below.

<Glass transition temperature: Tg>

The temperature increase rate was 20 degreeC per minute using the DSC6200 by Seiko Instruments, Ltd., and it measured under nitrogen stream.

<Weight average molecular weight and molecular weight distribution>

The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of polystyrene conversion were measured using tetrahydrofuran (THF) solvent using HLC-8020 gel permeation chromatography (GPC) manufactured by Tosoh Corporation. It was. In addition, Mn shows the number average molecular weight of polystyrene conversion.

<Intrinsic viscosity ([η] _inh )

Chloroform solvent was used as a solvent, and it measured by the Ubbelohde viscometer under the conditions of 30 degreeC by the polymer concentration of 0.5 g / dl.

<Heat weight reduction>

The thermal weight reduction of the compound and the film was measured under nitrogen flow (200 ml / min) using a differential thermal thermogravimetry device TG / DTA320 manufactured by Seiko Denshi Kogyo Co., Ltd. It heated up at 40 degree-C / min by predetermined | prescribed temperature, and evaluated the reduction amount 60 minutes after reaching | attaining temperature.

<Light transmittance, haze>

The total light transmittance and haze of the film were measured using the Haze meter HM-150 type by the Murakami Color Research Institute.

<Color (YI)>

The color (YI) of the film was measured using X-rite 8200 manufactured by Murakami Color Research Institute.

<Phase Difference of Transmitted Light>

Phase difference measurement of the sample was performed using KOBRA-21DH by Oji Keisoku Kiki. The measurement was performed about the sample which cut out arbitrary ten points from the film of full width x 1m, and made the average value into the phase difference value.

<Roll attachment>

In order to examine the presence or absence of deposits (additives and decomposition products thereof) during film formation, the presence or absence of the deposits on the casting rolls was visually checked, and ○: no deposits, ×: deposits were present.

<Number of point defects>

In order to examine the presence or absence of a point defect (change in fluidity, solubility, etc. due to deterioration of the resin (gel, gel)), five samples of 500 mm ² are cut out from the film center and the sample is dark. The number of point defects on the film identified by the reflected light was counted for the range of 500 mm ² or 200 mm ^2. The average value of the 5 samples was converted to the number per 1 m ² and displayed.

Durability Assessment

The test was done on 63 degreeC no rain conditions using the Sunshine Weathermeter by the company Suga Shikiki Co., Ltd., and the surface state, color (YI), and haze after 500 hours were observed. The surface condition was visually observed and evaluated by the following criteria.

○: no change

(Triangle | delta): Less than 10 micro cracks generate | occur | produced in the 100 mm x 100 mm visual field.

X: A remarkable crack generate | occur | produced.

<Synthesis of raw resin>

Synthesis Example-1 <Resin A>

227.5 parts of 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene and 22.5 parts of bicyclo [2.2.1] hept-2-ene, 1- 18 parts of hexene (molecular weight regulator) and 750 parts of toluene (solvent for ring-opening polymerization reaction) were put into the reaction container which carried out the nitrogen substitution, and this solution was heated at 60 degreeC. Next, 0.62 parts of toluene solution of triethylaluminum (1.5 mol / l) and tungsten chloride (t-butanol: methanol: tungsten = 0.35 mol: 0.3 mol: 1) modified with t-butanol / methanol were added to the solution in the reaction vessel. 3.7 parts of toluene solution (concentration 0.05 mol / l) of the mole) was added, and the ring-opening polymerization reaction was performed by heating and stirring this system at 80 degreeC for 3 hours, and the ring-opening copolymer solution was obtained. The polymerization conversion rate in this polymerization reaction was 97%.

4,000 parts of the ring-opening copolymer solution thus obtained were charged into an autoclave, 0.48 parts of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening copolymer solution, and the hydrogen gas pressure was 100 kg / cm ^2. The mixture was heated and stirred for 3 hours under conditions of a reaction temperature of 160 ° C. to perform a hydrogenation reaction.

After cooling the obtained reaction solution (hydrogenated polymer solution), hydrogen gas was discharged. The reaction solution was poured into a large amount of methanol, the coagulum was separated and recovered, and dried to obtain a hydrogenated cyclic olefin resin A. Tg of resin A was 140 degreeC. In addition, the one in terms of polystyrene measured by GPC method Mn, Mw, Mw / Mn was 24,000, 67,000, was 2.8, and the inherent viscosity (η _inh) is 0.49 dl / g, respectively.

Synthesis Example-2 <Resin B>

185.5 parts of 8-methoxycarbonyl-8-methyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] -3-dodecene, 62.5 parts of dicyclopentadiene (DCP), and bicyclo [2.2.1 ] The ring-opening copolymer was obtained like Example 1 except having heated at 100 degreeC using 2 parts of] hept-2-ene and 15 parts of 1-hexene (molecular weight regulator). The reaction rate was 96%. Moreover, hydrogenation reaction was performed similarly and the hydrogenated resin B was obtained. The glass transition temperature (Tg) of resin B was 145.0 degreeC.

The number average molecular weight (Mn) was 22,000, the weight average molecular weight (Mw) was 66,000, the molecular weight distribution (Mw / Mn) was 3.0, and the intrinsic viscosity (η _inh ) was 0.52.

<Filmmaking>

Example 1 (Film A-1)

I) (pentaerytrityl tetrakis-3- (3,5-di-t-butyl-4-hydride) as essential alkyl group-substituted phenolic compound (2) with respect to 100 parts of resin A using a twin screw extruder Oxyphenyl) propionate: melting point 115 ° C.) 0.3 part, as benzotriazole compound (3) v) (2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6 -(2H-benzotriazol-2-yl) phenol]: melting point 199 ° C.) Melt kneaded at 270 ° C. at a compounding ratio of 1.5 parts, extruded onto strand, and passed through a feeder luder after water cooling to obtain pellets. The obtained pellets were circulated, dehumidified and dried under nitrogen at 100 ° C. for 3 hours, then sent to a hopper and melted at a resin temperature of 270 ° C. using a single screw extruder having a screw diameter of 75 mmφ.

This molten resin was led to a 700 mm wide coat hanger die through a polymer filter (mesh 5 mu m) warmed to 280 ° C. at a rate of 30 kg / hr by a biaxially discharged gear pump. The pressure difference between the inlet and outlet of the filter was 3 MPa. Moreover, as a heater of a die, it set to 250 degreeC using the aluminum casting heater, The lip heater was additionally installed in the front lip part, and die lip temperature was controlled to 250 +/- 0.4 degreeC.

The lip opening degree was set to 0.5 mm in the width direction, and fine adjustment was performed by measuring thickness nonuniformity with the on-line thickness meter provided in the melt extrusion downstream side. The resin from the die was dropped in the vertical tangential direction of a 250 mmφ casting roll (surface roughness: 0.1 μ), pressed, and then pressed in sequence with two cooling rolls installed horizontally with respect to the casting roll shaft, and then peeled off. Taken under control by tension. The circumferential speed of the casting roll at this time was 7.6 m / min, and the space | interval from the die to the film crimping point of the casting roll was 65 mm. The obtained 100-micrometer-thick film was made into film A-1. Although the adhesion state of resin etc. of the die lip exit after manufacture was visually confirmed, the deposit was not seen.

Example 2 (Film A-2)

Compound (2) was ii) 1- [2- {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- [3- (3,5-di Except having changed into 0.3 parts of -t- butyl- 4-hydroxyphenyl) propionyloxy] -2,2,6,6- tetramethyl piperidine, operation similar to Example 1 was performed and film A-2 was obtained.

Example 3 (Film B-1)

Except having changed resin A into resin B and changing die temperature to 260 degreeC, operation was performed like Example 1 and film B-1 was obtained.

Example 4 (Film A-3)

I) pentaerythritol tetrakis-3- (3,5-di-t-butyl-4-hydroxyphenyl) propio as an essential compound (2) with respect to 100 parts of resin A using a twin screw extruder Vate 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol as 0.5 part of compound, as compound (3) ] Was operated in the same manner as in Example 1 at a compounding ratio of 2.5 to obtain a pellet. The obtained pellets were melted in the same manner as in Example 1, extruded from a 700 mm coat hanger die, and pressed into a 250 mmφ casting roll from the vertical tangential direction, and the surface was mirror-finished (surface roughness) from the opposite side of the casting roll to the melt. : 0.1 μ) of Chiba Kikai Kogyo Co., Ltd. sleeve type roll (incorporating two retaining rolls inside and a pipe-shaped metal thin film of 300 μ thickness) rated torque against the main speed of the casting roll. It was made to drive in the range of%, and was elastically deformed and crimped | bonded by the casting roll, and the both surfaces of the film were crimped | bonded by the surface. The films were pressed in turn with the second and third cooling rolls, and were pulled out at a tension of 4 kgf. At this time, the circumferential speed of the casting roll was 7.6 m / min, and the space | interval from the die to the film point of the casting roll was 65 mm. The 100-micrometer-thick film obtained was wound up as film A-3.

Comparative Examples 1 to 7

Hereinafter, it carried out similarly to Example 1, and obtained each film (A-4-10) from Comparative Examples 1-7. Each film composition and physical property values shown in the examples are shown in Table 1 below. In addition, it shows in Table 2 about the physical-property value of the compound used as compound (2) and (3).

<Stretching of film>

Example 5 (Film A-21)

The film A-1 was heated to 143 ° C. in a tenter, stretched 1.5 times at a stretching rate of 400% / min, cooled in this state for about 2 minutes in an atmosphere of 110 ° C., and then further cooled to room temperature. It took out and slit both ends, and obtained the stretched film A-21 of 300 mm width. The light transmittance of the obtained film was 92%, the haze was 0.2%, and the phase difference expression property calculated by [phase difference (nm) / film thickness (nm)] / draw ratio was 3.21x10 <^-3> . The stretching conditions and characteristic evaluation results of A-21 are shown in Table 3 below.

Examples 6-9, Comparative Examples 8-14

First, each of the stretched films (A-21 to 31, B-21) was obtained in the same manner as in Example 5 above using the extruded films exemplified in Examples and Comparative Examples, under the predetermined temperatures shown in Table 3. Drawing conditions and the evaluation results of the characteristics are shown in Table 3.

Comparing Examples 1 to 4 and Comparative Example 1, Comparative Example 1 is poor in thermal stability because there are few components (2) essential in the present invention, and many of the point defects of the extruded film are present. In Comparative Examples 2 and 7, on the contrary, since there are too many (2) or (3) components, adherence to a casting roll occurs under the influence of decomposition products, and the point defects of a film also increase. In Comparative Examples 3 and 4, since the melting point of the compound (2) is too low or too high relative to the polymer (1), deposits increase due to volatilization or decomposition of the compound. In Comparative Examples 5 and 6, since only one of the essential compounds (2) and (3) is included, the increase in the number of point defects and the durability of the film (Comparative Example 8) in which the copper film was stretched deteriorate. Moreover, in the comparative example 12, it turns out that the phase difference expression property of the film which extended | stretched the film whose melting | fusing point of compound (2) was too low worsened, and the effect of this invention was not acquired.

The optical film obtained by this invention is various, for example, a mobile telephone, a digital information terminal, a pager, navigation, a vehicle-mounted liquid crystal display, a liquid crystal monitor, a liquid crystal television, a light control panel, a display for OA equipment, a display for AV equipment, etc. It can be used for phase difference films, such as a liquid crystal display element, an electroluminescent display element, or a touch panel, a polarizing plate protective film, a viewing angle compensation film, a light diffusion plate, a display board, etc. It is also useful as a wave plate used for recording / reproducing apparatus of optical discs such as CD, CD-R, MD, MO, DVD.

Claims (7)

(1) To 100 parts by weight of a polymer having a structural unit represented by the following formula (1), (2) 0.1 to 4 parts by weight of an alkyl group-substituted phenolic compound having a melting point in the range of glass transition temperature (Tg) -35 ° C to Tg + 75 ° C of the polymer, and (3) 0.1 to 4 parts by weight of a benzotriazole compound having a melting point in the range of the glass transition temperature (Tg) -35 ° C to Tg + 75 ° C of the polymer. Melt-extrusion of the composition which has a thing, The manufacturing method of the optical film characterized by the above-mentioned. <Formula 1>

(Of the general formula (1) of, R ¹ to R ⁴ is a group of a hydrogen atom, a halogen atom, a C 1 -C 30 hydrocarbon group, or is the monovalent other organic group, and each may be the same or different, and the R ¹ to R ⁴ Any two may combine with each other to form a monocyclic or polycyclic structure, m is zero or a positive integer, and p is zero or a positive integer) The manufacturing method of the optical film of Claim 1 whose heat weight reduction rates, when the said (2) phenol type compound and (3) benzotriazole type compound hold | maintain at 280 degreeC for 1 hour are respectively 20 weight% or less. The manufacturing method of the optical film of Claim 1 or 2 which melt-transfers the molten body of the said composition on both sides of a transfer roll, and forms into a film. The optical film obtained by the manufacturing method of the optical film of any one of Claims 1-3. The phase difference (Re) to provide to the transmitted light of the stretched film obtained when the uniaxial stretching of draw ratio 1.3-2.7 times is performed at the temperature of Tg + 5 degreeC or more of the polymer (1), The following formula (1) Satisfying optical film. <Equation 1> [(Re / film thickness) / drawing ratio] ＞ 3.0 × 10 ^-3 (Re: retardation value expressed in nm, film thickness: nm) Retardation film containing the optical film of Claim 4 or 5. The optical film of Claim 4 or 5 was used as a protective film on at least one surface, The polarizing plate characterized by the above-mentioned.