JP2008031319A - Norbornene polymer, film, polarizing plate and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a norbornene polymer film whose retardation has reverse wavelength dispersion characteristics. <P>SOLUTION: The film is comprised of a norbornene polymer containing a recurring unit represented by general formula (I). In the formula, R<SP>1</SP>and R<SP>2</SP>are each a hydrogen atom, an optionally substituted alkyl group or an optionally substituted aryl group; L and L' are each a bivalent linking group or a single bond; and A and A' are each an aromatic group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to norbornene-based polymers, films using the same (in particular, various functional films such as retardation films, viewing angle widening films, antireflection films used in plasma displays, polarizing plate protective films), polarizing plates, liquid crystal displays The apparatus relates to a norbornene polymer.

A film of a norbornene-based addition polymer (hereinafter referred to as a norbornene-based polymer) obtained by vinyl polymerization of a norbornene-based compound is characterized by high retardation (Rth) in the thickness direction, and thus can be applied to a negative C plate. (Patent Document 1). Furthermore, by stretching this, the main chain of the norbornene-based polymer is aligned in the stretching direction and expresses retardation (Re), and can be applied to a negative biaxial retardation plate. That is, a film of a norbornene polymer is promising as a retardation film having high Re and Rth. In particular, a preferable value can be taken as a retardation film of a VA (vertical alignment) liquid crystal display device.

On the other hand, a retardation film of a liquid crystal display device in recent years has characteristics in which values of Re and Rth are continuously different not only at specific Re and Rth values at a certain wavelength but also at wavelengths in the visible light region (400 nm to 700 nm) ( Chromatic dispersion) is required. For example, a retardation film of a vertical alignment (VA) liquid crystal display device is required to have reverse wavelength dispersion characteristics in which the Re value increases as the wavelength increases. For example, when Re at wavelengths of 450 nm, 590 nm, and 630 nm is Re ₄₅₀ , Re ₅₉₀ , and Re ₆₃₀ , it is required that Re ₄₅₀ <Re ₅₉₀ <Re ₆₃₀ .

In general, it is effective to introduce a component having a long absorption wavelength in order to fluctuate the chromatic dispersion. To date, Patent Document 2 describes only a polymer having a phenyl group introduced therein.

International Publication WO2004 / 049011 Pamphlet International Publication WO2004 / 007587 Pamphlet

In the study conducted by the present inventors, although the wavelength dispersibility of the above-described norbornene-based polymer film containing a phenyl group is improved, the degree is small and insufficient to improve the color appearance of the liquid crystal display device. It turned out to be. Therefore, a norbornene-based polymer film that can increase the degree of wavelength dispersion is desired.

As a result of intensive studies to solve the above problems, the present inventors have found that the wavelength dispersion characteristic of Re in the norbornene polymer film containing the norbornene unit having two aromatic groups is reverse dispersion and the degree thereof is large. I found out that Further, the aromatic group has a maximum absorption wavelength of 270 to 400 nm, and the molar absorption coefficient of the maximum absorption wavelength is 10 to 100,000 [mol ⁻¹ dm ³ cm ⁻¹ ]. In the case of a body, the present inventors have found that this dispersion characteristic is particularly large and have reached the present invention. It has been found that a high-quality polarizing plate and a liquid crystal display device can be obtained by incorporating the norbornene polymer film of the present invention.

（式中、Ｒ¹およびＲ²は、それぞれ、水素原子、置換基を有していてもよいアルキル基、または、置換基を有してもよいアリール基であり、ＬおよびＬ'は、それぞれ、二価の連結基または単結合であり、ＡおよびＡ'はそれぞれ、芳香族基である。）
（２）前記ＬおよびＬ'が、それぞれ、単結合、カルボニル基またはアセチレン基である（１）に記載のノルボルネン系重合体。
（３）前記Ａおよび／またはＡ’が、２７０ｎｍ〜４００ｎｍに極大吸収波長を有し、該極大吸収波長のモル吸光係数が１０〜１０００００[mol^-1dm³cm^-1]である芳香族化合物の１水素離脱体である（１）または（２）に記載のノルボルネン系重合体。
（４）前記芳香族化合物が、２〜４環式芳香族化合物である（３）に記載のノルボルネン系重合体。
（５）前記L-ＡおよびL'-Ａ'が、いずれもエキソ連結である（１）〜（４）のいずれか１項に記載のノルボルネン系重合体。
（６）さらに下記一般式（II）で表される繰り返し単位を少なくとも１種含む（１）〜（５）のいずれか１項に記載のノルボルネン系重合体。

（式中、Ｒ⁵、Ｒ⁶、Ｒ⁷およびＲ⁸は、それぞれ、水素原子、置換基を有していてもよいアルキル基、置換基を有してもよいアリール基、または、−Ｌ’’−Ｏ−ＣＯ−Ｒ⁹（Ｌ’’は二価の連結基または単結合であり、Ｒ⁹はアルキル基である）であり、Ｒ⁵、Ｒ⁶、Ｒ⁷およびＲ⁸の少なくとも一つは−Ｌ’’−Ｏ−ＣＯ−Ｒ⁹である。）
（７）前記Ｒ⁵、Ｒ⁶、Ｒ⁷およびＲ⁸のうち３つがそれぞれ、水素原子または置換基を有していてもよいアルキル基である（６）に記載のノルボルネン系重合体。
（８）前記Ｌ'' が単結合またはアルキレン基である（６）または（７）に記載のノルボルネン系重合体。
（９）前記Ｒ⁹が炭素数１〜５のアルキル基である（６）〜（８）のいずれか１項に記載のノルボルネン系重合体。
（１０）一般式（Ｉ）で表される繰り返し単位および一般式（II）で表される繰り返し単位のみから形成された（６）〜（９）のいずれか１項に記載のノルボルネン系重合体。
（１１）一般式（I）で表される繰り返し単位の重合組成比率が０％より多く８０％未満である（１）〜（１０）のいずれか１項に記載のノルボルネン系重合体。
（１２）（１）〜（１１）のいずれか１項に記載のノルボルネン系重合体を含む、フィルム。
（１３）波長４５０ｎｍにおける面内レターデーションＲｅ₄₅₀と波長６３０ｎｍにおける面内レターデーションＲｅ₆₃₀の差ΔＲｅ＝Ｒｅ₆₃₀−Ｒｅ₄₅₀が、１０ｎｍ≦ΔＲｅ≦１００ｎｍを満足する（１２）に記載のフィルム。
（１４）波長５９０ｎｍにおける面内レターデーションＲｅ₅₉₀が、３０ｎｍ≦Ｒｅ₅₉₀≦２００ｎｍを満足する（１２）または（１３）に記載のフィルム。
（１５）偏光膜と、（１２）〜（１４）のいずれか１項に記載のフィルムを有することを特徴とする偏光板。
（１６）（１５）に記載の偏光板を有することを特徴とする液晶表示装置。 Means for solving the above problems are as follows.
(1) A norbornene-based polymer comprising at least one repeating unit represented by the following general formula (I).

(In the formula, R ¹ and R ² are each a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and L and L ′ are each A divalent linking group or a single bond, and A and A ′ are each an aromatic group.)
(2) The norbornene polymer according to (1), wherein L and L ′ are each a single bond, a carbonyl group, or an acetylene group.
(3) Aromatic compounds in which A and / or A ′ has a maximum absorption wavelength at 270 nm to 400 nm, and the molar absorption coefficient of the maximum absorption wavelength is 10 to 100,000 [mol ⁻¹ dm ³ cm ⁻¹ ]. The norbornene-based polymer according to (1) or (2), wherein
(4) The norbornene-based polymer according to (3), wherein the aromatic compound is a 2-4 cyclic aromatic compound.
(5) The norbornene-based polymer according to any one of (1) to (4), wherein both L-A and L′-A ′ are exo-linked.
(6) The norbornene polymer according to any one of (1) to (5), further comprising at least one repeating unit represented by the following general formula (II).

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or —L ′. '-O-CO-R ⁹ (L ″ is a divalent linking group or a single bond, R ⁹ is an alkyl group), and is at least one of R ⁵ , R ⁶ , R ⁷ and R ⁸ . is -L '' - is a O-CO-R ^9).
(7) The norbornene polymer according to (6), wherein three of R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom or an alkyl group which may have a substituent.
(8) The norbornene polymer according to (6) or (7), wherein L ″ is a single bond or an alkylene group.
(9) The norbornene polymer according to any one of (6) to (8), wherein R ⁹ is an alkyl group having 1 to 5 carbon atoms.
(10) The norbornene-based polymer according to any one of (6) to (9), which is formed from only the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II). .
(11) The norbornene polymer according to any one of (1) to (10), wherein the polymerization composition ratio of the repeating unit represented by the general formula (I) is more than 0% and less than 80%.
(12) A film comprising the norbornene polymer according to any one of (1) to (11).
(13) The film according to (12), wherein the difference ΔRe = Re ₆₃₀ −Re ₄₅₀ between the in-plane retardation Re ₄₅₀ at a wavelength of ₄₅₀ nm and the in-plane retardation Re _{630 at} a wavelength of 630 nm satisfies 10 nm ≦ ΔRe ≦ 100 nm.
(14) The film according to (12) or (13), wherein the in-plane retardation Re ₅₉₀ at a wavelength of 590 nm satisfies 30 nm ≦ Re ₅₉₀ ≦ 200 nm.
(15) A polarizing plate comprising a polarizing film and the film described in any one of (12) to (14).
(16) A liquid crystal display device comprising the polarizing plate according to (15).

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Norbornene polymer]
The norbornene-based polymer of the present invention includes a repeating unit represented by the following general formula (I). The norbornene polymer in the present invention is a homopolymer or copolymer obtained by polymerizing a norbornene compound. 1 type or multiple types may be sufficient as the repeating unit represented by the following general formula (I), and other repeating units may be included so that it may mention later.

In general formula (I), R ¹ and R ² are each a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent. There is no particular limitation. R ¹ and R ² are each preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

In general formula (I), L and L ′ each represent a divalent linking group or a single bond, and may be the same or different. Examples of the divalent linking group include an alkylene group (preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. For example, a methylene group (—CH ₂ —), ethylene Group (—CH ₂ CH ₂ —), trimethylene group (—CH ₂ CH ₂ CH ₂ —) and the like, an arylene group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, Particularly preferably, it has 6 to 12 carbon atoms, and examples thereof include a phenylene group (—C ₆ H ₄ —), a naphthylene group (—C ₁₀ H ₆ —), and the like, and an oxyalkylene group (preferably 1 to 1 carbon atom). 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, for example, oxymethylene group (-OCH ₂ -), an oxyethylene group (-OCH ₂ CH ₂ -), and the like. ), Oxy ants A -lene group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as an oxyphenylene group (—OC ₆ H ₄ —), an oxynaphthylene group (—OC ₁₀ H ₆ -. where), etc.), an oxycarbonyl group (-OCO-), imino group (-CONH-), carbonyl group (-CO-), an acetylene group (-CC-), ureylene groups (-NHCONH -), A hetero atom such as a sulfur atom or an oxygen atom, and an amino group (-NR ^a- : R ^a represents ^a substituent). Two or more of these linking groups may be combined. Furthermore, these linking groups may be substituted with a substituent.
L and L ′ are preferably a single bond or a linking group having 3 or less atoms, more preferably a single bond, a carbonyl group, or an acetylene group, since the side chain as short as possible has a smaller photoelasticity and is preferable for the film. More preferably, it is a single bond.
Note that LA and L′-A ′ are preferably exo, exo or endo, endo, and more preferably exo, exo, since the same three-dimensional structure has a high stacking effect between aromatic rings.

A and A ′ each represent an aromatic group, and examples thereof include a form of a 1-hydrogen leaving body of an aromatic compound. 1 As the hydrogen-eliminating substance, benzene, pentalene, naphthalene, azulene, heptalene, biphenylene, indacene, acenaphthylene, phenanthrene, anthracene, fluoracene, acephenanthrylene, triphenylene, pyrene, chrysene, naphthacene, priadene, picene, perylene, pentaphen, Monocyclic or condensed hydrocarbon compounds such as pentacene, tetraphenylene, hexaphene, hexacene, rubicene, coronene, trinaphthylene, heptaphene, heptacene, pyracene, obalene; thiophene, thianthrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxati In, pyrrole, imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine, pyrimidin, pyridazine, Ndridine, isoindole, indole, indazole, purine, quinolidine, isoquinoline, quinoline, phthalazine, naphthyridine, quinoxaline, sinoline, pteridine, carbazole, beta carboline, phenanthridine, acridine, perimidine, phenanthrine, phenazine, phenolsazine, phenothiazine, furanazine And those having these substituents.

Further, A and A ′ are preferably at least one, more preferably both have a maximum absorption wavelength of 270 to 400 nm, and the molar absorption coefficient of the maximum absorption wavelength is 10 to 100,000 [mol ⁻¹ dm ³ cm ^{−. 1} ] A hydrogen-desorbed product of an aromatic compound is preferred. More preferably, it is a 1 hydrogen leaving body of an aromatic compound having a maximum absorption wavelength at 300 to 400 nm. It is preferable to use an aromatic compound having a hydrogen absorption of 270 nm or longer, which has a wavelength dispersion characteristic, and an absorption wavelength of 400 nm or less tends to be less yellowish.
In the present specification, the maximum absorption wavelength is an aromatic having a maximum absorption wavelength at 270 nm to 400 nm and a molar extinction coefficient at the maximum absorption wavelength of 10 to 100,000 [mol ⁻¹ dm ³ cm ⁻¹ ]. This refers to the maximum point of the absorption peak when the compound is dissolved in methylene chloride at an appropriate concentration (if insoluble, it is dissolved with hexane, heptane, etc.), and the absorption wavelength is measured at 25 ° C. with a normal UV measuring instrument. The unit of the molar extinction coefficient is [mol ⁻¹ dm ³ cm ⁻¹ ], but unless otherwise specified, the unit of the molar extinction coefficient is defined in this. The maximum absorption wavelength is not necessarily the maximum absorption wavelength. There may be multiple local maxima.
The molar extinction coefficient of the aromatic compound having a maximum absorption wavelength at 270 nm to 400 nm is preferably 100 to 100,000, more preferably 120 to 100,000, and still more preferably 130 to 100. , 000.
In addition, A and A ′ are preferably 1-hydrogen leaving bodies of 2 to 4 cyclic aromatic compounds among aromatic groups, and more preferably 1-hydrogen leaving bodies of naphthalene, anthracene, phenanthrene, and pyrene. preferable.

The norbornene-based polymer of the present invention may contain other repeating units without departing from the spirit of the present invention. When other repeating units are contained, the polymerization composition ratio of the repeating units represented by the general formula (I) is preferably more than 0% and less than 80%, more preferably more than 0% and less than 60%. More preferably, it is 5 to 40%.
In particular, the norbornene-based polymer of the present invention preferably comprises only a repeating unit represented by the general formula (I) and a repeating unit represented by the general formula (II) described later. “Only” in this case does not depart from the gist of the present invention except that it contains no components other than the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II). Other components may be included within the range. For example, reaction residues such as monomers constituting these repeating units and additives usually used in polymerization may be contained.
By making it less than 80%, the hydrophobicity of the norbornene polymer does not become too high, the solubility in a solvent tends to improve, and the moisture permeability of the film tends to decrease. On the other hand, when the content is 5% or more, the norbornene-based polymer tends to be hydrophilic and moisture permeability tends to increase. Thus, by adjusting the content of the repeating unit represented by the general formula (I), a film having appropriate solubility and moisture permeability can be produced. In particular, the above range is preferable because a water-soluble polarizer is attached as a film for a liquid crystal display device, so that it can have appropriate water permeability.

As such another repeating unit, a repeating unit derived from a norbornene compound is preferable, and a repeating unit represented by the following general formula (II) is more preferable.

（式中、Ｒ⁵、Ｒ⁶、Ｒ⁷およびＲ⁸は、それぞれ、水素原子、置換基を有していてもよいアルキル基、置換基を有してもよいアリール基、または、−Ｌ’’−Ｏ−ＣＯ−Ｒ⁹（Ｌ’’は二価の連結基または単結合であり、Ｒ⁹はアルキル基である）であり、Ｒ⁵、Ｒ⁶、Ｒ⁷およびＲ⁸の少なくとも一つは−Ｌ’’−Ｏ−ＣＯ−Ｒ⁹である。）

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or —L ′. '-O-CO-R ⁹ (L ″ is a divalent linking group or a single bond, R ⁹ is an alkyl group), and is at least one of R ⁵ , R ⁶ , R ⁷ and R ⁸ . is -L '' - is a O-CO-R ^9).

R ⁵ , R ⁶ , R ⁷ and R ⁸ other than -L ''-O-CO-R ⁹ are each preferably a hydrogen atom or an optionally substituted alkyl group, Or an alkyl group is more preferable, and a hydrogen atom is still more preferable. In particular, it is preferable that three of R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom or an alkyl group which may have a substituent.
Among R ⁵ , R ⁶ , R ⁷ and R ⁸ , the number of substituents of —L ″ —O—CO—R ⁹ is preferably 1 or 2, and more preferably 1. R ⁹ is preferably an alkyl group having 6 or less carbon atoms. The smaller the number of carbon atoms contained in R ⁹ , the better because the photoelasticity of the film tends to be small. Therefore, R ⁹ is preferably an alkyl group having 5 or less carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group is more preferable.

L ″ represents a divalent linking group or a single bond. Examples of the divalent linking group include an alkylene group (preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. For example, a methylene group (—CH ₂ —), ethylene Group (—CH ₂ CH ₂ —), trimethylene group (—CH ₂ CH ₂ CH ₂ —) and the like, an arylene group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, Particularly preferably, it has 6 to 12 carbon atoms, and examples thereof include a phenylene group (—C ₆ H ₄ —), a naphthylene group (—C ₁₀ H ₆ —), and the like, and an oxyalkylene group (preferably 1 to 1 carbon atom). 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, for example, oxymethylene group (-OCH ₂ -), an oxyethylene group (-OCH ₂ CH ₂ -), and the like. ), Oxy ants A -lene group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as an oxyphenylene group (—OC ₆ H ₄ —), an oxynaphthylene group (—OC ₁₀ H ₆ -. where), etc.), an oxycarbonyl group (-OCO-), imino group (-CONH-), carbonyl group (-CO-), an acetylene group (-CC-), ureylene groups (-NHCONH -), A hetero atom such as a sulfur atom or an oxygen atom, and an amino group (-NR ^a- : R ^a represents ^a substituent). Two or more of these linking groups may be combined. Furthermore, these linking groups may be substituted with a substituent.
L ″ is preferably a single bond or an alkylene group, more preferably a single bond or an alkylene group having 3 or less carbon atoms, and even more preferably a single bond or a methylene group.

The norbornene polymer of the present invention preferably has a polystyrene-equivalent number average molecular weight (Mn) of 10,000 to 1,000,000 as measured by gel permeation chromatogram using tetrahydrofuran as a solvent. More preferably, it is 50,000-500,000. Moreover, 15,000-1,500,000 are preferable and, as for the weight average molecular weight (Mw) of polystyrene conversion, 70,000-700,000 are more preferable.
When the number average molecular weight in terms of polystyrene is 10,000 or more and the weight average molecular weight is 15,000 or more, the fracture strength tends to be more preferable, the number average molecular weight in terms of polystyrene is 1,000,000 or less, and the weight average molecular weight. If it is 1,500,000 or less, the molding processability as a sheet tends to be improved, and the solution viscosity tends to be low when used as a cast film or the like, and tends to be handled easily. The molecular weight distribution (weight average molecular weight / number average molecular weight) is preferably 1.1 to 5.0, more preferably 1.1 to 4.0, and still more preferably 1.1 to 3.5. By setting the molecular weight distribution of the norbornene-based polymer within the above range, the norbornene-based polymer solution (dope) is likely to be uniform, and a good film can be easily produced.

The norbornene-based polymer of the present invention can be obtained by the following production method. [Pd (CH ₃ CN) ₄ ] [BF ₄ ] ₂ , di-μ-chloro-bis- (6-methoxybicyclo [2.2.1] hept-2-ene-endo-5σ, 2π) -Pd ( Hereinafter abbreviated as “I”) and methylalumoxane (MAO), I and AgBF ₄ , I and AgSbF ₆ , [(η ³ -allyl) PdCl] ₂ and AgSbF ₆ , [(η ³ -allyl) PdCl] ₂ And AgBF ₄ , [(η ³ -crotyl) Pd (cyclooctadiene)] [PF ₆ ], [(η ³ -allyl) Pd (η ⁵ -cyclopentadienyl)] ₂ , tricyclohexylphosphine and dimethylanilinium Tetrakispentafluorophenylborate or trityltetrakispentafluorophenylborate, palladium bisacetylacetonate, tricyclohexylphosphine and dimethylanilinium teto Lakispentafluorophenylborate, [(η ³ -allyl) PdCl] ₂ and tricyclohexylphosphine and tributylallyltin or allylmagnesium chloride and dimethylanilinium tetrakispentafluorophenylborate, [(η ⁵ -cyclopentadienyl) Ni ( Methyl) (triphenylphosphine)] and trispentafluorophenylborane, [(η ³ -crotyl) Ni (cyclooctadiene)] [B ((CF ₃ ) ₂ C ₆ H ₄ ) ₄ ], [NiBr (NPMe ₃ )] ₄ and MAO, Ni (Octoate) ₂ and MAO, Ni (Octoate) ₂ and B (C ₆ F ₅ ) ₃ and AlEt ₃ , Ni (Octoate) ₂ and [ph ₃ C] [B (C ₆ F ₅ ) _4] and Ali-Bu _3, Co (neodecanoate) and the periodic table group 8 of Ni MAO like, Pd Using a catalyst to form a cationic complex or cation complex such as Co, in a range of 20 to 150 ° C. in a solvent, monomers can be obtained by either alone or copolymerization. Solvents include cycloaliphatic hydrocarbon solvents such as cyclohexane, cyclopentane and methylcyclopentane; aliphatic hydrocarbon solvents such as pentane, hexane, heptane and octane; aromatic hydrocarbon solvents such as toluene, benzene and xylene; dichloromethane Halogenated hydrocarbon solvents such as 1,2-dichloroethylene and chlorobenzene; polar solvents such as ethyl acetate, butyl acetate, γ-butyrolactone, propylene glycol dimethyl ether and nitromethane. As other synthesis methods, Macromolecules, 1996, 29, 2755, Macromolecules, 2002, 35, 8969, International Patent Publication No. WO2004 / 7564 The method described in 1 is also preferably used.

The monomer constituting the repeating unit represented by the general formula (I) and / or (II) can be generally synthesized as follows. The Diels-Alder reaction (Path 1) of the corresponding olefin and cyclopentadiene (obtained by thermal decomposition of dicyclopentadiene) or a method of introducing an aryl group into norbornadiene (Synthesis 1998, 1249, Tetrahedron 1989, 45, 5263, etc. (Path 2; L = L ′ = single bond, A = A ′ = C ₆ H ₅ is exemplified) to obtain a norbornene-based compound I. A norbornene compound II is obtained by Diels-Alder reaction of the corresponding olefin and cyclopentadiene (obtained by thermally decomposing dicyclopentadiene) (Path 3). A homopolymer or a copolymer can be obtained by the above-described polymerization method. The composition ratio (x and 100-x) of the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II) can be adjusted by appropriately changing the mixing ratio. The norbornene compound I may be copolymerized with two or more other norbornene compounds.

Examples of the norbornene polymer homopolymer in the present invention are shown below, but are not limited thereto.

Examples of the norbornene-based copolymer in the present invention are shown below, but are not limited thereto. “X” and “100-X” represent copolymer composition ratios, and the range of X is preferably 0 <X <80, more preferably 0 <X <60, and 5 <X <40. Is more preferable.

[Norbornene polymer film]
The norbornene-based polymer of the present invention is useful as a film material. In particular, films prepared using the polymer include substrates of liquid crystal display devices, light guide plates, polarizing films, retardation films, liquid crystal backlights, liquid crystal panels, OHP films, transparent conductive films, and the like. Suitable for optical use film. The norbornene-based polymer represented by the general formula (I) is suitably used for optical materials such as optical discs, optical fibers, lenses, and prisms, electronic components, medical devices, containers, and the like.

[Method for producing norbornene polymer film]
The film of this invention contains the norbornene-type polymer containing the repeating unit represented by the said general formula (I), and can be produced by forming into a film from this polymer. There are two methods for film formation: hot melt film formation and solution film formation, and both are applicable, but in the present invention, a solution film formation method capable of obtaining an excellent surface film is used. preferable. The solution casting method is described below.

(Solution casting method)
(Preparation of dope)
First, a solution (dope) of the polymer used for film formation is prepared. The organic solvent used for the preparation of the dope is not particularly limited as long as it can be dissolved, cast, and formed into a film, and the purpose can be achieved. For example, chlorinated solvents such as dichloromethane and chloroform, chain hydrocarbons having 3 to 12 carbon atoms (hexane, octane, isooctane, decane, etc.), cyclic hydrocarbons (cyclopentane, cyclohexane, decalin, etc.), aromatic carbonization Hydrogen (benzene, toluene, xylene, etc.), ester (ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, pentyl acetate, etc.), ketone (acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone) , Cyclohexanone and methylcyclohexanone), ether (diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, Preferably the solvent selected from over like Le and phenetole). Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol. The preferable boiling point of the organic solvent is 35 ° C to 200 ° C. The solvent used for the preparation of the solution can be used by mixing two or more kinds of solvents in order to adjust the solution properties such as drying property and viscosity. Further, as long as the solvent is dissolved in the mixed solvent, a poor solvent is added. It is also possible.

  A preferred poor solvent can be appropriately selected. When a chlorinated organic solvent is used as the good solvent, alcohols can be preferably used. Alcohols may preferably be linear, branched or cyclic, and among them, saturated aliphatic hydrocarbons are preferred. The hydroxyl group of the alcohol may be any of primary to tertiary. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Among the poor solvents, particularly monovalent alcohols have an effect of reducing the peeling resistance and can be preferably used. Particularly preferred alcohols vary depending on the good solvent to be selected, but considering the drying load, alcohols having a boiling point of 120 ° C. or lower are preferable, monohydric alcohols having 1 to 6 carbon atoms are more preferable, and alcohols having 1 to 4 carbon atoms Can be particularly preferably used.

  A particularly preferred mixed solvent for preparing the dope is a combination in which dichloromethane is the main solvent and at least one alcohol selected from methanol, ethanol, propanol, isopropanol, or butanol is a poor solvent.

  For the preparation of the dope, a method by stirring and dissolving at room temperature, after stirring the polymer at room temperature to swell the polymer, cooling to −20 ° C. to −100 ° C., and cooling again to 20 ° C. to 100 ° C. to dissolve There are a dissolution method, a high-temperature dissolution method that dissolves at a temperature equal to or higher than the boiling point of the main solvent in a closed container, and a method that dissolves at a high temperature and high pressure up to the critical point of the solvent. The viscosity of the dope is preferably in the range of 1 to 500 Pa · s at 25 ° C., more preferably in the range of 5 to 200 Pa · s.

  Prior to casting, it is preferable to filter off foreign matters such as undissolved matter, dust, and impurities using a suitable filter medium such as a wire mesh or flannel. The viscosity immediately before film formation may be in a range that allows casting during film formation, and is preferably adjusted to a range of 5 Pa · s to 1000 Pa · s, more preferably in a range of 15 Pa · s to 500 Pa · s. The range of 30 Pa · s to 200 Pa · s is more preferable. In addition, although the temperature at this time will not be specifically limited if it is the temperature at the time of the casting, Preferably it is -5-70 degreeC, More preferably, it is -5-35 degreeC.

(Additive)
The film of the present invention may contain additives other than the polymer, and such additives may be added at any stage of the process for producing the film. Additives can be selected depending on the application, such as deterioration inhibitors, UV inhibitors, retardation (optical anisotropy) regulators, fine particles, peeling accelerators, infrared absorbers, etc. Can be mentioned. These additives may be solid or oily. In the case of film production by the solution casting method, the addition time may be added at any time during the dope preparation process, or an additive is added to the final preparation process of the dope preparation process. You may go. In the case of film production by the melting method, it may be added at the time of resin pellet production, or may be kneaded at the time of film production. The amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ.

  From the viewpoint of preventing film deterioration, a deterioration (oxidation) inhibitor is preferably used. For example, 2,6-di-tert-butyl, 4-methylphenol, 4,4′-thiobis- (6-tert-butyl-3-methylphenol), pentaerythrityl-tetrakis [3- (3,5- Phenolic or hydroquinone antioxidants such as di-tert-butyl-4-hydroxyphenyl) propionate can be added. Furthermore, phosphorus antioxidants such as tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite It is preferable to The addition amount of the antioxidant is 0.05 to 5.0 parts by mass with respect to 100 parts by mass of the polymer.

  From the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal, an ultraviolet absorber is preferably used. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Specific examples of ultraviolet absorbers preferably used in the present invention include, for example, hindered phenol compounds, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salts Compounds and the like. The addition amount of these ultraviolet light inhibitors is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the norbornene polymer.

  In order to improve the slipperiness of the film surface, fine particles (mat agent) are preferably used. By using this, unevenness is imparted to the film surface, that is, by increasing the roughness of the film surface (matization), the blocking between the films can be reduced. The presence of fine particles in the film or on at least one surface of the film significantly improves the adhesion between the polarizer and the film during polarizing plate processing. The matting agent used in the present invention is inorganic fine particles, for example, fine particles having an average particle size of 0.05 μm to 0.5 μm, preferably 0.08 μm to 0.3 μm, more preferably 0.1 μm to 0 μm. .25 μm. In the fine particles, silicon dioxide, silicone and titanium dioxide are preferable as the inorganic compound, fluorine resin, nylon, polypropylene and chlorinated polyether are preferable as the polymer compound, silicon dioxide is more preferable, and surface treatment with organic matter is performed. Silicon is more preferred.

  In order to reduce the peeling resistance of the film, a peeling accelerator is preferably used. As preferred release agents, phosphate ester surfactants, carboxylic acid or carboxylate surfactants, sulfonic acid or sulfonate surfactants, and sulfate ester surfactants are effective. A fluorine-based surfactant in which part of the hydrogen atoms bonded to the hydrocarbon chain of the surfactant is substituted with fluorine atoms is also effective. The addition amount of the release agent is preferably 0.05 to 5% by mass, more preferably 0.1 to 2% by mass, and further preferably 0.1 to 0.5% by mass with respect to the norbornene-based polymer.

(Film production)
For the method and equipment for producing the film of the present invention, the same solution casting film forming method and solution casting film forming apparatus as those used for producing a known cellulose triacetate film are preferably used. The dope prepared from the dissolving machine (kettle) is temporarily stored in a storage kettle, and the foam contained in the dope is defoamed for final preparation.

  JP 2000-301555, JP 2000-301558, JP 7-032391, JP 3-193316, JP 5-086212, JP 62-037113, JP 2-276607, The cellulose acylate film forming techniques described in JP-A-55-014201, JP-A-2-111511, and JP-A-2-208650 can be preferably used in the present invention.

(Multilayer casting)
The dope may be cast as a single layer liquid on a smooth band or drum as a metal support, or a plurality of dopes of two or more layers may be cast. In the case of multilayer casting, the inner and outer thicknesses are not particularly limited, but preferably the outer thickness is 1 to 50% of the total film thickness, and more preferably 2 to 30%.

(Casting)
As a solution casting method, a method in which the prepared dope is uniformly extruded from a pressure die onto a metal support, and a method using a doctor blade in which the dope once cast on the metal support is adjusted with a blade is used. Alternatively, there is a method using a reverse roll coater that adjusts with a reverse rotating roll, and a method using a pressure die is preferable. The temperature of the dope used for casting is preferably −10 to 55 ° C., more preferably 25 to 50 ° C. In that case, all of the steps may be the same or different at various points in the step. When they are different, it is preferable that the temperature is a desired temperature immediately before casting.

(Dry)
Drying of the dope on the metal support in the production of the film is generally accomplished by applying hot air from the surface side of the metal support (eg, drum or band), that is, the surface of the web on the metal support, drum or A method of applying hot air from the back side of the band, contacting the temperature controlled liquid from the back side opposite the dope casting surface of the band or drum, and heating the drum or band by heat transfer to control the surface temperature Although there are methods, the back surface liquid heat transfer method is preferable. The surface temperature of the metal support before casting may be any number as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the metal support, the temperature should be set to 1 to 10 ° C. lower than the boiling point of the lowest boiling solvent. Is preferred. This is not the case when the casting dope is cooled and peeled off without drying.

(Peeling)
When peeling a raw dry film from a metal support, if the peeling resistance (peeling load) is large, the film is irregularly stretched in the film forming direction, resulting in uneven optical anisotropy. In particular, when the peeling load is large, a portion stretched stepwise in the film forming direction and a portion unstretched are alternately generated, resulting in a distribution in retardation. When loaded in a liquid crystal display device, the line or strip becomes uneven. In order not to cause such a problem, it is preferable to set the peeling load of the film to 0.25 N or less per 1 cm of the film peeling width. The peeling load is more preferably 0.2 N / cm or less, further preferably 0.15 N or less, and particularly preferably 0.10 N or less. When the peeling load is 0.2 N / cm or less, even in a liquid crystal display device in which unevenness is likely to appear, no unevenness due to peeling is observed, which is particularly preferable. As a method for reducing the peeling load, there are a method of adding a release agent as described above and a method of selecting a solvent composition to be used. The preferable residual volatile content at the time of peeling is 5 to 60% by mass. 10-50 mass% is further more preferable, and 20-40 mass% is especially preferable. Peeling with a high volatile content is preferable because the drying rate can be increased and the productivity is improved. On the other hand, when the volatile content is high, the strength and elasticity of the film are small, and the film is cut or stretched against the peeling force. Further, the self-holding force after peeling is poor, and deformation, wrinkles and nicks are likely to occur. It also causes distribution in the retardation.

(Stretching)
When the film produced by the solution casting method is further stretched, it is preferably carried out in a state where the solvent still remains in the film immediately after peeling. The purpose of stretching is (1) to obtain a film having excellent flatness without wrinkles and deformation, and (2) to increase the in-plane retardation of the film. When stretching is performed for the purpose of (1), stretching is performed at a relatively high temperature, and stretching is performed at a low magnification from 1% to 10% at most. A stretch of 2-5% is particularly preferred. When stretching for the purposes of both (1) and (2) or only for the purpose of (2), the film is stretched at a relatively low temperature and a stretch ratio of 5 to 150%.

  The stretching of the film may be uniaxial stretching only in the longitudinal or lateral direction, or may be simultaneous or sequential biaxial stretching. The birefringence of the retardation film for a VA liquid crystal cell or OCB (Optically Compensatory Bend) liquid crystal cell is preferably such that the refractive index in the width direction is larger than the refractive index in the length direction. Therefore, it is preferable to stretch more in the width direction.

  The thickness of the finished film (after drying) of the present invention varies depending on the purpose of use, but is usually in the range of 20 to 500 μm, preferably in the range of 30 to 150 μm, particularly 40 to 110 μm for liquid crystal display devices. It is preferable.

[Characteristics of film]
In the film of the present invention, the difference ΔRe = Re ₆₃₀ −Re ₄₅₀ between the in-plane retardation Re ₄₅₀ at a wavelength of ₄₅₀ nm and the in-plane retardation Re _{630 at} a wavelength of 630 nm preferably satisfies 10 nm ≦ ΔRe ≦ 100 nm. ΔRe ≦ 80 nm is more preferable, and 10 nm ≦ ΔRe ≦ 60 nm is most preferable.
The preferred optical properties of the film of the present invention vary depending on the application of the film. Below, the preferable range in each use of in-plane retardation (Re) and thickness direction retardation (Rth) which converted the thickness of the film into 80 micrometers is shown.

  When used as a polarizing plate protective film: Re is preferably 0 nm ≦ Re ≦ 5 nm, more preferably 0 nm ≦ Re ≦ 3 nm. Rth is preferably 0 nm ≦ Rth ≦ 50 nm, more preferably 0 nm ≦ Rth ≦ 35 nm, and particularly preferably 0 nm ≦ Rth ≦ 10 nm.

  When used as a retardation film: The range of Re and Rth varies depending on the type of retardation film and there are various needs, but 0 nm ≦ Re ≦ 100 nm and 0 nm ≦ Rth ≦ 400 nm are preferable. In the TN mode, 0 nm ≦ Re ≦ 20 nm, 40 nm ≦ Rth ≦ 80 nm, and in the VA mode, 20 nm ≦ Re ≦ 80 nm and 80 nm ≦ Rth ≦ 400 nm are more preferable. In particular, the preferable range in the VA mode is 30 nm ≦ Re ≦ 75 nm, 120 nm ≦ Rth. ≦ 250 nm, when compensating with one retardation film, 50 nm ≦ Re ≦ 75 nm, 180 nm ≦ Rth ≦ 250 nm, when compensating with two retardation films, 30 nm ≦ Re ≦ 50 nm, 80 nm ≦ Rth ≦ 140 nm. These are preferred embodiments as a VA mode compensation film in terms of color shift at the time of black display and the viewing angle dependency of contrast.

  The film of the present invention can achieve desired optical characteristics by appropriately adjusting process conditions such as copolymerization ratio, additive type and amount, stretch ratio, residual volatile content at the time of peeling.

In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. Re (λ) is measured by making light with a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotating axis) (if there is no slow axis, any in-plane The light of wavelength λ nm is incident from each of the inclined directions in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction (with the direction of the rotation axis as the rotation axis). KOBRA 21ADH or WR calculates based on the measured retardation value, the assumed average refractive index, and the input film thickness value.

注記：
上記のＲｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値を表す。
式（１）におけるｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘおよびｎｙに直交する方向の屈折率を表す。
Ｒｔｈ＝(（ｎｘ＋ｎｙ）／２ − ｎｚ) ｘ ｄ --- 式（２）
測定されるフィルムが１軸や２軸の屈折率楕円体で表現できないもの、いわゆる光学軸（optic axis)がないフィルムの場合には、以下の方法によりＲｔｈ（λ）は算出される。
Ｒｔｈ(λ)は前記Ｒｅ(λ)を、面内の遅相軸（KOBRA 21ADHまたはWRにより判断される）を傾斜軸（回転軸）としてフィルム法線方向に対して−５０度から＋５０度まで１０度ステップで各々その傾斜した方向から波長λｎｍの光を入射させて１１点測定し、その測定されたレターデーション値と平均屈折率の仮定値および入力された膜厚値を基にKOBRA 21ADHまたはWRが算出する。
上記の測定において、平均屈折率の仮定値は、ポリマーハンドブック（JOHN WILEY＆SONS，INC）、各種光学フィルムのカタログの値を使用することができる。平均屈折率の値が既知でないものについてはアッベ屈折計で測定することができる。主な光学フィルムの平均屈折率の値を以下に例示する： セルロースアシレート（１．４８）、シクロオレフィンポリマー（１．５２）、ポリカーボネート（１．５９）、ポリメチルメタクリレート（１．４９）、ポリスチレン（１．５９）である。これら平均屈折率の仮定値と膜厚を入力することで、KOBRA 21ADHまたはWRはｎｘ、ｎｙ、ｎｚを算出する。この算出されたｎｘ、ｎｙ、ｎｚよりＮｚ＝（ｎｘ−ｎｚ）／（ｎｘ−ｎｙ）がさらに算出される。 In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing the sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (1) and (2).

Note:
The above Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction.
In formula (1), nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents the refractive index in the direction perpendicular to nx and ny. .
Rth = ((nx + ny) / 2-nz) x d --- Formula (2)
In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optic axis, Rth (λ) is calculated by the following method.
Rth (λ) is from -50 ° to + 50 ° with respect to the normal direction of the film, with Re (λ) as the slow axis (indicated by KOBRA 21ADH or WR) in the plane and the tilt axis (rotation axis). In each of the 10 degree steps, light of wavelength λ nm is incident from each inclined direction and measured at 11 points. Based on the measured retardation value, the assumed average refractive index, and the input film thickness value, KOBRA 21ADH or Calculated by WR.
In the above measurement, as the assumed value of the average refractive index, the values in the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of the main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). By inputting these assumed values of average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

In the case of using the film of the present invention as a protective film for polarizing plate, the value of the photoelastic is ^{0.5 × 10 -13 ~9.0 × 10 -13} [cm 2 / dyn], moisture permeability values However, it is preferable that the value (converted assuming the thickness of the film as 80 μm) is 180 to 435 [g / cm ² 24 h]. The value of photoelasticity is more preferably 0.5 × 10 ^{−13 to} 7.0 × 10 ⁻¹³ [cm ² / dyn], and 0.5 × 10 ^{−13 to} 5.0 × 10 ⁻¹³ [ More preferably, it is cm ² / dyn]. In addition, the value of moisture permeability (however, the value obtained by converting the film thickness to 80 μm) is more preferably 180 to 400 [g / cm ² 24h], and 180 to 350 [g / cm ² 24h]. Is more preferable. When the film of the present invention has the above-described properties, when it is used as a protective film for a polarizing plate, it is possible to reduce a decrease in performance due to the influence of humidity.

[Polarizer]
The polarizing plate of the present invention has at least the film of the present invention and a polarizer. Usually, a polarizing plate has a polarizer and two protective films disposed on both sides thereof. The film of the present invention can be used as both or one protective film. A normal cellulose acetate film or the like may be used for the other protective film. Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. The iodine polarizer and the dye polarizer are generally produced using a polyvinyl alcohol film. When the film of the present invention is used as a polarizing plate protective film, the film is subjected to a surface treatment as described later, and then the film-treated surface and a polarizer are bonded together using an adhesive. Examples of the adhesive used include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and gelatin. The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and is further constructed by laminating a protective film on one surface of the polarizing plate and a separate film on the opposite surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate. The film is preferably bonded so that the transmission axis of the polarizer and the slow axis of the film coincide with each other.

(Film surface treatment)
In the present invention, the surface of the film is preferably surface-treated in order to improve the adhesion between the polarizer and the protective film. As for the surface treatment, any method may be used as long as the adhesiveness can be improved. Preferred examples of the surface treatment include glow discharge treatment, ultraviolet irradiation treatment, corona treatment, and flame treatment. The glow discharge treatment here refers to so-called low temperature plasma that occurs under low pressure gas. In the present invention, plasma treatment under atmospheric pressure is also preferable. In addition, the details of the glow discharge treatment are described in US Pat. No. 3,462,335, US Pat. No. 3,761,299, US Pat. No. 4,072,769, and British Patent No. 891469. A method described in JP-A-59-556430 in which the discharge atmosphere gas composition is changed to only the gas species generated in the container by subjecting the polyester support itself to a discharge treatment after the start of discharge is also used. In addition, the method described in Japanese Patent Publication No. 60-16614, in which the surface temperature of the film is set to 80 ° C. to 180 ° C. when performing the vacuum glow discharge treatment, can also be applied.

  As for the degree of surface treatment, the preferred range varies depending on the type of surface treatment, but as a result of the surface treatment, the contact angle with the pure water on the surface of the protective film subjected to the surface treatment is preferably less than 50 °. . The contact angle is more preferably 25 ° or more and less than 45 °. When the contact angle with the pure water on the surface of the protective film is in the above range, the adhesive strength between the protective film and the polarizing film becomes good.

(adhesive)
When laminating a polarizer made of polyvinyl alcohol and the surface-treated film of the present invention, it is preferable to use an adhesive containing a water-soluble polymer. Water-soluble polymers preferably used for the adhesive include N-vinyl pyrrolidone, acrylic acid, methacrylic acid, maleic acid, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, vinyl alcohol, methyl vinyl ether, vinyl acetate. , Acrylamide, methacrylamide, diacetone acrylamide, vinyl imidazole, etc., homopolymers or polymers having ethylenically unsaturated monomers as constituents, polyoxyethylene, polyoxypropylene, poly-2-methyloxazoline, methylcellulose, hydroxyethylcellulose , Hydroxypropylcellulose gelatin, and the like. Of these, PVA and gelatin are preferred in the present invention. The thickness of the adhesive layer is preferably 0.01 to 5 μm after drying, and more preferably 0.05 to 3 μm.

(Antireflection layer)
It is preferable to provide a functional film such as an antireflection layer on the protective film disposed on the opposite side of the polarizing plate from the liquid crystal cell. In particular, in the present invention, at least a light scattering layer and a low refractive index layer are laminated in this order on the protective film, or an intermediate refractive index layer, a high refractive index layer, and a low refractive index layer are arranged in this order on the protective film. A laminated antireflection layer is preferably used.

(Light scattering layer)
The light scattering layer is formed for the purpose of contributing to the film light diffusibility due to surface scattering and / or internal scattering and hard coat properties for improving the scratch resistance of the film. Therefore, it is formed including a binder for imparting hard coat properties, matte particles for imparting light diffusibility, and inorganic fillers for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength as necessary. The The thickness of the light scattering layer is preferably from 1 to 10 μm, more preferably from 1.2 to 6 μm, from the viewpoint of imparting hard coat properties and from the viewpoint of curling and suppressing deterioration of brittleness.

(Other layers of antireflection layer)
Further, a hard coat layer, a forward scattering layer, a primer layer, an antistatic layer, an undercoat layer, a protective layer, and the like may be provided.

(Hard coat layer)
The hard coat layer is provided on the surface of the support in order to impart physical strength to the protective film provided with the antireflection layer. In particular, it is preferably provided between the support and the high refractive index layer. The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of a light and / or heat curable compound. As the curable functional group, a photopolymerizable functional group is preferable, and the organometallic compound containing a hydrolyzable functional group is preferably an organic alkoxysilyl compound.

(Antistatic layer)
In the case of providing an antistatic layer, it is preferable to impart conductivity with a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less. The use of hygroscopic substances, water-soluble inorganic salts, certain surfactants, cationic polymers, anionic polymers, colloidal silica, etc. can give a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ). There is a problem that dependency is large, and sufficient conductivity cannot be secured at low humidity. Therefore, a metal oxide is preferable as the conductive layer material.

[Liquid Crystal Display]
The film of the present invention, a retardation film comprising the film, and a polarizing plate using the film can be used for liquid crystal cells and liquid crystal display devices in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal, AFLC) Various display modes such as HAN (Hybrid Aligned Nematic) have been proposed. Of these, the OCB mode or the VA mode can be preferably used.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

  Among the norbornene polymer raw materials used in the present invention, 5-norbornen-2-yl acetate (bicyclo [2.2.1] hept-5-en-2-yl acetate) (NBOAc) can be purchased from Aldrich. . Other norbornene compounds were produced as in the following synthesis examples.

(Synthesis Example 1: Synthesis of exo, exo-diphenylnorbornene)
Norbornadiene (Tokyo Kasei) 53.9 g, Bromobenzene (Wako Pure Chemical) 205.3 g, Sodium tetraphenyl borate (Aldrich) 160.4 g, Anisole (Wako Pure Chemical) 400 mL, Tetrakis triphenyl 3.7 g of phosphine palladium (manufactured by Aldrich) was charged into the flask and stirred at 100 ° C. for 5 hours. The obtained mixture was filtered, and the filtrate was subjected to liquid separation extraction with ethyl acetate / water. This was evaporated to remove volatile components such as ethyl acetate, bromobenzene and anisole. The residue was subjected to column chromatography (Eluent: hexane), concentrated, and a solution dissolved in hexane was recrystallized at −30 ° C. to obtain 113 g of exo, exo-diphenylnorbornene (DiPhNB).

(Synthesis Example 2: Synthesis of exo, exo- (phenyl) (pyrenyl) norbornene)
In Synthesis Example 1, bromopyrene (manufactured by Wako Pure Chemical Industries, Ltd.) was added in an equimolar amount instead of bromobenzene, and exo, exo- (phenyl) (pyrenyl) norbornene (PhPyrNB) was obtained by the same synthesis method.

(Synthesis Example 3: Synthesis of exo, exo- (phenyl) (1-naphthyl) norbornene)
In Synthesis Example 1, 1-bromonaphthalene (manufactured by Aldrich) was charged in an equimolar amount instead of bromobenzene, and exo, exo- (phenyl) (1-naphthyl) norbornene (PhNaphNB) was obtained by the same synthesis method.

(Synthesis Example 4: Synthesis of exo, exo-dibenzoylnorbornene)
20 g of diphenyliodonium tetrafluoroborate, 10 g of norbornadiene (manufactured by Tokyo Chemical Industry Co., Ltd.), 50 mL of dimethylformamide (manufactured by Wako Pure Chemical Industries, Ltd.), 3 g of palladium acetate (manufactured by Aldrich) were charged, and carbon monoxide (manufactured by Sumitomo Seika) was bubbled. . A solution prepared by dissolving 20 g of sodium tetraphenylborate (manufactured by Aldrich) in 100 mL of dimethylformamide was added dropwise thereto. After completion of dropping, the reaction was allowed to proceed at room temperature for 2 hours. Nitrogen was bubbled to remove residual carbon monoxide. The residue was separated and extracted with ethyl acetate / water, the organic layer was dried over magnesium sulfate, and this was filtered. After concentration by evaporation, the resulting crude product was subjected to column chromatography. When this was recrystallized, exo, exo-dibenzoylnorbornene (Di (Bzy) NB) as white crystals was obtained.

(Synthesis Example 5: Synthesis of exo, exo- (phenyl) (phenylethynyl) norbornene)
20 g of diphenyliodonium tetrafluoroborate, 10 g of norbornadiene, 50 mL of dimethylformamide, and 3 g of palladium acetate were charged. A solution prepared by dissolving 5.6 g of phenylacetylene in 10 mL of dimethylformamide was added dropwise thereto. After completion of dropping, the reaction was allowed to proceed at room temperature for 2 hours. This was quenched with a saturated aqueous solution of potassium fucca, separated and extracted with ethyl acetate / water, the organic layer was dried over magnesium sulfate, and filtered. After concentration by evaporation, the resulting crude product was subjected to column chromatography. When this was recrystallized, white crystals of exo, exo- (phenyl) (phenylethynyl) norbornene (Ph (PhEthynyl) NB) were obtained.

(Synthesis Example 6: Synthesis of 5-acetoxymethyl-2-norbornene)
1094 g of dicyclopentadiene (manufactured by Wako Pure Chemical Industries, Ltd.), 1772 g of allyl acetate (manufactured by Wako Pure Chemical Industries, Ltd.) and 1 g of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.) were charged into the autoclave, and the air gap was replaced with nitrogen. The mixture was stirred for 9 hours at an internal temperature of 180 ° C. in a closed system (rotational speed = 300 rpm). The reaction mixture was filtered and the volatile components were evaporated. The residue was subjected to precision distillation (reflux ratio = 10/1, pressure = 10 mmHg, top temperature = 89 ° C.) to obtain 1550 g of colorless and transparent 5-acetoxymethyl-2-norbornene (NBCH ₂ OAc).

(Synthesis Example 7: Synthesis of 5-butyloxymethyl-2-norbornene)
In Synthesis Example 6, 5-butyloxymethyl-2-norbornene (NBCH ₂ OCOC ₃ H ₇ ) was obtained in the same manner as in Synthesis Example 6, except that allyl acetate was changed to allyl butyrate (Aldrich).

(Synthesis Example 8)
1000 mL of purified toluene and 0.5 mol of exo, exo-DiPhNB synthesized in Synthesis Example 1 were charged into a reaction vessel. Next, 0.0125 mmol of allyl palladium chloride dimer (manufactured by Tokyo Kasei Co., Ltd.) and 0.025 mmol of tricyclohexylphosphine (manufactured by Strem Co.) dissolved in 10 mL of toluene, dimethylanilinium tetrakispentafluorophenylborate (Strem) dissolved in 5 mL of methylene chloride 0.05 mmol, and 0.030 mmol of allyltributyltin (Aldrich) dissolved in 10 mL of toluene was added to the reaction vessel. Heating was started and stirred at 60 ° C. for 1 hour. During this time, toluene was added as appropriate with an increase in the viscosity of the reaction solution. 0.01 mol of 1-hexene (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise, and the mixture was further reacted for 1 hour. The obtained reaction solution was put into excess methanol to precipitate a polymer P-1. The precipitate was collected and washed with methanol. The resulting polymer was vacuum dried at 110 ° C. for 6 hours.

  The obtained polymer was dissolved in tetrahydrofuran, and the molecular weight was measured by gel permeation chromatography. The results are shown in Table 1.

(Synthesis Examples 9 to 11)
The exo, exo-DiPhNB charged in Synthesis Example 8 was synthesized from the exo, exo-PhPyrNB synthesized in Synthesis Example 2, the exo, exo-Di (Bzy) NB synthesized in Synthesis Example 4, and the exo, exo synthesized in Synthesis Example 5. Synthesis was performed in the same manner as in Synthesis Example 8 except that -Ph (PhEthynyl) NB was used, and P-2 to 4 were obtained. The results are shown in Table 1.

(Synthesis Example 12)
100 mL of purified toluene and 0.5 mol of NBCH ₂ OAc were charged into the reaction vessel. Next, 0.05 mmol of allyl palladium chloride dimer (manufactured by Tokyo Kasei Co., Ltd.) dissolved in 10 mL of toluene and 0.1 mmol of tricyclohexylphosphine (manufactured by Strem Co.), dimethylanilinium tetrakispentafluorophenylborate (Strem) dissolved in 5 mL of methylene chloride 0.2 mmol, and 0.15 mmol of allyltributyltin (Aldrich) dissolved in 10 mL of toluene was added to the reaction vessel. When heating was started and the temperature reached 90 ° C., 0.05 mol of exo, exo-DiPhNB dissolved in 20 parts by mass of toluene was added dropwise over 10 minutes. The mixture was reacted at 90-100 ° C. for 6 hours. During this time, toluene was added as appropriate with an increase in the viscosity of the reaction solution. 0.01 mol of 1-hexene (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise, and the mixture was further reacted for 1 hour. The obtained reaction solution was poured into excess methanol to precipitate a polymer P-5. The precipitate was collected and washed with methanol. The resulting polymer was vacuum dried at 110 ° C. for 6 hours.

  The obtained polymer was dissolved in tetrahydrofuran, and the molecular weight was measured by gel permeation chromatography. The results are shown in Table 1.

When dissolved in deuterated chloroform and measured by ¹ HNMR, the integrated value of the peak appearing at 3.2 to 4.8 ppm (methylene hydrogen bonded to the acetoxy group) is A, and the peak appearing at 7 to 8 ppm (hydrogen of the phenyl group) Assuming that the integral value of B is B, a relational expression of A: B = 2 (100−x): 10x holds for x in the expression of Table 1. According to this, the value of x in the formula of Table 1 was calculated. The results are shown in Table 1.

(Synthesis Example 13)
In Synthesis Example 12, P-6 having different copolymerization ratios was synthesized by increasing the amount of exo, exo-DiPhNB. The molecular weight and the value of x were determined in the same manner. The results are shown in Table 1.

(Synthesis Example 14)
In Synthesis Example 12, P-7 was synthesized using NBCH ₂ OAc as NBCH ₂ OCOC ₃ H ₇ . The molecular weight and X value were determined in the same manner. The results are shown in Table 1.

(Synthesis Example 15)
P-8 was obtained by synthesizing in the same manner as in Synthesis Example 13 except that NBCH ₂ OAc charged in Synthesis Example 13 was changed to NBOAc. The molecular weight was determined similarly. When dissolved in deuterated chloroform and measured by ¹ HNMR, the integrated value of the peak appearing at 4.3 to 5.3 ppm (hydrogen bonded to carbon bonded to the acetoxy group) is C, and the peak appearing at 7 to 8 ppm (phenyl group) Assuming that the integral value of (hydrogen) is D, the relational expression C: D = (100−x): 10x is established. According to this, the value of x was obtained. The results are shown in Table 1.

(Synthesis Examples 16 to 19)
Synthesis example except that exo, exo-DiPhNB charged in Synthesis Example 13 is changed to exo, exo-PhPyrNB, exo, exo-PhNaphNB, exo, exo-Di (Bzy) NB, exo, exo-Ph (PhEthynyl) NB In the same manner as in Example 13, P-9 to 12 were obtained. Similarly to the above, the molecular weight and the value of x were determined by the ratio of the integral value of methylene hydrogen bonded to the acetoxy group and the integral value of hydrogen of the phenyl group. The results are shown in Table 1.

(Synthesis Example 20)
674.0 g of dicyclopentadiene (manufactured by Wako Pure Chemical Industries, Ltd.), 508.0 g of styrene (manufactured by Wako Pure Chemical Industries, Ltd.) and 1 g of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.) were charged into the autoclave, and the air gap was replaced with nitrogen. The mixture was stirred for 8 hours at an internal temperature of 180 ° C. in a closed system (rotational speed = 300 rpm). The reaction mixture was flash-distilled to remove residual cyclopentadiene, styrene, and polymer, thereby obtaining a preferential PhNB. This was subjected to precision distillation to obtain colorless and transparent endorich-PhNB. The obtained colorless and transparent liquid was subjected to gas chromatography to measure the peak purity. As a result, the purity was 98.5% and the endo / exo ratio was 78/22.

(Synthesis Example 21)
In Synthesis Example 6, 5-hexyloxymethyl-2-norbornene (NBCH ₂ OCOC ₅ H ₁₁ ) was obtained in the same manner as in Synthesis Example 6 except that allyl acetate was changed to allyl hexanoate (manufactured by Wako Pure Chemical Industries, Ltd.). .

(Synthesis Example 22)
P-13 was obtained in the same manner as in Synthesis Example 16 except that NBCH ₂ OAc was changed to NBCH ₂ OCOC ₅ H ₁₁ in Synthesis Example 16. Similarly to the above, the molecular weight and the value of x were determined by the ratio between the integral value of methylene hydrogen bonded to the hexyloxy group and the integral value of hydrogen in the aromatic region. The results are shown in Table 1.

(Synthesis Example 23)
A-1 was obtained in the same manner as in Synthesis Example 16 except that PhPyrNB was changed to endorich-PhNB in Synthesis Example 16. Similarly to the above, the molecular weight and the value of x were determined by the ratio of the integral value of methylene hydrogen bonded to the acetoxy group and the integral value of hydrogen in the aromatic region. The results are shown in Table 1.

In the above norbornene polymer, a hydrogen-desorbed product of benzene, naphthalene, or pyrene is used as a long wave component. A methylene chloride solution of 10 mg / L of benzene, naphthalene and pyrene was prepared and measured with a UV measuring device UV-2550 manufactured by Shimadzu Corporation. The maximum absorption of benzene was not detected at a wavelength of 300 nm or more. On the other hand, the maximum absorption wavelength of naphthalene and pyrene was detected at 300 nm to 400 nm. A plurality of maximum absorption wavelengths were detected for pyrene. The main maximum absorption wavelength and molar extinction coefficient are shown in the table below.

[Example 1: Production of polymer film and measurement of film properties]
(Film formation)
50 g of the polymer P-1 obtained above was dissolved in 200 g of methylene chloride, and this was filtered under pressure. The obtained dope was cast on an A3 large hydrophobic glass plate using an applicator. This was dried for 5 minutes in a 25 ° C. closed system, and then dried for 10 minutes in a blast dryer at 40 ° C. The film was peeled off from the glass plate and sandwiched between stainless steel frames, which were dried in a dryer at 100 ° C. for 30 minutes and in a dryer at 133 ° C. for 30 minutes to obtain a transparent film F-1. Similarly, P-2 to 13 and A-1 were formed to obtain transparent films F-2 to 13 and FA-1.

(Stretching)
F-5 to 13 and FA-1 were cut into 5 cm length and 5 cm width. This was stretched at a temperature of 230 ° C. to 250 ° C. using an automatic biaxial stretching machine manufactured by Imoto Seisakusho to obtain stretched films F-5 ′ to 13 ′ and FA-1 ′. The stretching temperature and the stretching ratio are as shown in Table 2.

(Physical property measurement)
Re of the stretched film at a wavelength of 450 nm to 750 nm was measured as described above. The thickness of the film was measured at three points on an arbitrary portion with a digital micrometer, and the average value was taken. The converted Re with a thickness of 80 μm at wavelengths of 450 nm, 590 nm, and 650 nm was Re ₄₅₀ , Re ₅₉₀ , and Re ₆₃₀ . ΔRe = Re ₆₃₀ −Re ₄₅₀ was calculated as an index representing the wavelength dispersion characteristic of Re.

Table 2 summarizes the evaluation results of Re ₅₉₀ and ΔRe = Re ₆₃₀ −Re ₄₅₀ of the film produced above.

  As can be seen from the results in Table 2, Re of the film of the present invention has reverse wavelength dispersion characteristics. To that extent, the polymer film into which a long wave component such as naphthalene or pyrene is introduced is more highly expressed. On the other hand, the films A-1 and A-1 ′ of Comparative Examples found in Patent Document 1 are forward wavelength dispersion and the degree of wavelength dispersion is small.

[Example 2: Production and evaluation of polarizing plate]
The produced film F-6 ′ and a cellulose acylate film (Fuji Photo Film Co., Ltd., Fuji TAC) were immersed in an aqueous 1.5N sodium hydroxide solution at 60 ° C. for 2 minutes. Thereafter, it was immersed in a 0.1N sulfuric acid aqueous solution for 30 seconds, and then passed through a water washing bath to obtain saponified F-6 ′ and Fuji TAC.

  According to Example 1 of Japanese Patent Laid-Open No. 2001-141926, a peripheral speed difference is given between two pairs of nip rolls, and a 75 μm thick polyvinyl alcohol film (manufactured by Kuraray Co., Ltd., 9 × 75RS) is stretched in the longitudinal direction. A polarizing film was obtained.

  The polarizing film thus obtained and the saponified F-6 ′ were mixed with polyvinyl alcohol (PVA) (PVA-117H, 3% by weight) aqueous solution as an adhesive, and the longitudinal direction of the film was 45 °. Thus, a polarizing plate Pol-1 was prepared by laminating with a layer structure of “saponified F-6 ′ / polarizing film / saponified Fuji TAC”.

[Example 3: Production and evaluation of liquid crystal display device]
Among two pairs of polarizing plates installed with a liquid crystal layer sandwiched between 26-inch and 40-inch liquid crystal display devices (manufactured by Sharp Corporation) using VA type liquid crystal cells, a polarizing plate on one side on the viewer side is used. It peeled off and the said polarizing plate Pol-1 was affixed instead using the adhesive. A liquid crystal display device was manufactured by arranging the transmission axis of the polarizing plate on the viewer side and the transmission axis of the polarizing plate on the backlight side to be orthogonal to each other. Color unevenness of the obtained liquid crystal display device was observed. The liquid crystal display device incorporating the polarizing plate Pol-1 of the present invention had no color unevenness and was very excellent.

Claims (16)

A norbornene polymer comprising at least one repeating unit represented by the following general formula (I):

(In the formula, R ¹ and R ² are each a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and L and L ′ are each A divalent linking group or a single bond, and A and A ′ are each an aromatic group.) The norbornene-based polymer according to claim 1, wherein L and L 'are each a single bond, a carbonyl group, or an acetylene group. 1 hydrogen of an aromatic compound in which A and / or A ′ has a maximum absorption wavelength at 270 nm to 400 nm, and the molar absorption coefficient of the maximum absorption wavelength is 10 to 100,000 [mol ⁻¹ dm ³ cm ⁻¹ ] The norbornene-based polymer according to claim 1 or 2, which is a detached body. The norbornene-based polymer according to claim 3, wherein the aromatic compound is a 2-4 cyclic aromatic compound. The norbornene-based polymer according to any one of claims 1 to 4, wherein both L-A and L'-A 'are exo-linked. Furthermore, the norbornene-type polymer of any one of Claims 1-5 containing at least 1 sort (s) of the repeating unit represented by the following general formula (II).

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or —L ′. '-O-CO-R ⁹ (L ″ is a divalent linking group or a single bond, R ⁹ is an alkyl group), and is at least one of R ⁵ , R ⁶ , R ⁷ and R ⁸ . is -L '' - is a O-CO-R ^9). 7. The norbornene polymer according to claim 6, wherein three of R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom or an alkyl group which may have a substituent. The norbornene polymer according to claim 6 or 7, wherein L '' is a single bond or an alkylene group. The norbornene-based polymer according to any one of claims 6 to 8, wherein R ⁹ is an alkyl group having 1 to 5 carbon atoms. The norbornene-based polymer according to any one of claims 6 to 9, formed only from the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II). The norbornene-based polymer according to any one of claims 1 to 10, wherein a polymerization composition ratio of the repeating unit represented by the general formula (I) is more than 0% and less than 80%. The film containing the norbornene-type polymer of any one of Claims 1-11. The film according to claim 12, wherein a difference ΔRe = Re ₆₃₀ −Re ₄₅₀ between the in-plane retardation Re ₄₅₀ at a wavelength of ₄₅₀ nm and the in-plane retardation Re _{630 at} a wavelength of 630 nm satisfies 10 nm ≦ ΔRe ≦ 100 nm. 14. The film according to claim 12, wherein the in-plane retardation Re ₅₉₀ at a wavelength of 590 nm satisfies 30 nm ≦ Re ₅₉₀ ≦ 200 nm. A polarizing plate comprising a polarizing film and the film according to claim 12. A liquid crystal display device comprising the polarizing plate according to claim 15.