TWI501009B - TN (Twist Nematic) mode liquid crystal display element, a method of manufacturing the same, and a retardation film for TN mode liquid crystal display element - Google Patents

Description

TN (Twist Nematic) mode liquid crystal display element, manufacturing method thereof, and retardation film for TN mode liquid crystal display element

The present invention relates to a TN mode liquid crystal display device having a retardation film made of a thermoplastic resin, a method for producing the liquid crystal display device, and a retardation film for a TN mode liquid crystal display device.

In recent years, liquid crystal display elements have been sought to be larger, and at the same time, uniform and high-contrast display performance has been sought for liquid crystal display elements. Further, as the size of the screen increases, display performance with a wider range of viewing angles is sought. In order to obtain such a wide viewing angle, the polarizing plate having the retardation film and the polarizer is generally disposed on the outer side of the liquid crystal cell, and the viewing angle compensation function is provided.

In the TN mode liquid crystal display device, a generally usable method is a method of compensating for a viewing angle by using a polarizing plate which uses an optical film coated with a discotic liquid crystal as a retardation film.

However, in the above-mentioned polarizing plate, the retardation film is coated with liquid crystal, and the optical axis tends to be uneven. Further, there is a problem in that the unevenness of the coating or the incorporation of foreign matter may cause defects in the surface of the film. The inhomogeneity or in-plane heterogeneity of such a film optical axis is related to the inhomogeneity of display characteristics, and particularly the occurrence of defects.

The inventors of the present invention have found that by using a phase difference film having a specific optical characteristic that highly controls the optical axis by the stretching step, defects are not generated due to foreign matter mixing, and therefore, no bright spots are generated in the surface of the liquid crystal display element. Achieve a wide range of perspective compensation. SUMMARY OF THE INVENTION An object of the present invention is to provide a TN mode liquid crystal display element which has no bright spots and has a wide range of viewing angle characteristics.

The TN (Twist Nematic) mode liquid crystal display device of the present invention (hereinafter also referred to simply as "liquid crystal display device") is characterized in that two kinds of polarizing plates each having a retardation film made of a thermoplastic resin and a polarizer are used to hold the liquid crystal. Any one of the retardation films constituting the respective polarizing plates is arranged to satisfy the following formulas (i) and (ii).

(i) 20nm≦R0≦150nm

(ii) 1.1≦NZ≦4.3

(here, R0 represents the phase difference in the plane of the film, NZ represents the NZ coefficient, and the maximum refractive index in the film plane at a light wavelength of 550 nm is nx, and the refractive index in the direction perpendicular to nx in the plane of the film is ny. The refractive index in the thickness direction of the film is nz, and when the thickness is d (nm), the value obtained by R0 = (nx - ny) × d and the formula NZ = (nx - nz) / (nx - ny).

In the liquid crystal display device of the present invention, two polarizing plates are placed on the viewer side and the back side of the liquid crystal display element, and the retardation film constituting each of the polarizing plates satisfies the following formula (iii).

(iii) 200 nm ≦R0f×NZf+R0r×NZr≦260nm

(here, R0f and NZf respectively represent R0 and NZ of the optical film on the observer side of the liquid crystal display element, and R0r and NZr respectively represent R0 and NZ of the optical film on the back side of the liquid crystal display element).

Any one of the liquid crystal display elements of the present invention, which is a retardation film, preferably satisfies the following formulas (iv) and (v).

(iv) 70nm≦R0≦150nm

(v) 1.1≦NZ≦1.5

In the liquid crystal display device of the present invention, the thermoplastic resin constituting the retardation film is a cyclic olefin resin having a repeating unit represented by the following formula (I).

[In the formula (I), m is an integer of 1 or more, p is an integer of 0 or more, D is a group represented by -CH=CH- or -CH ₂ CH ₂ -, and R ¹ to R ⁴ are each independently Is a group selected from a hydrogen atom; a halogen atom; a linking group containing an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; a group of polar groups or Further, R ¹ and R ² may be integrated to form a divalent hydrocarbon group, and R ³ and R ⁴ may be integrated to form a divalent hydrocarbon group; and R ¹ and R ² may be bonded to each other to form a carbocyclic or heterocyclic group. The ring, R ³ and R ⁴ may be bonded to each other to form a carbocyclic or heterocyclic ring, and the carbocyclic or heterocyclic ring may be a monocyclic ring or a polycyclic ring].

Further, the liquid crystal display element of the present invention preferably has a protective film made of a polarizing plate.

A method for producing a liquid crystal display device of the present invention, comprising the steps of: stretching a raw material film made of a thermoplastic resin to form a retardation film satisfying the above formulas (i) and (ii); a step of forming a polarizing plate by overlapping the difference film and the polarizer; and overlapping the obtained polarizing plate with the liquid crystal cell.

The retardation film for a TN mode liquid crystal display device of the present invention (hereinafter also referred to simply as "phase difference film") is obtained by extending a material film composed of a thermoplastic resin and satisfying the above formula (i) and (ii).

[Results of the invention]

According to the present invention, it is possible to provide a TN mode liquid crystal display element which can achieve no bright spot occurrence, has a wide range of viewing angle characteristics, has no display unevenness, and displays stable display characteristics, and a manufacturing method thereof, and can be used for the liquid crystal display. A retardation film for a TN mode liquid crystal display element in which an element is highly controlled in optical properties.

[Best form for implementing the invention]

Hereinafter, the present invention will be specifically described.

<thermoplastic resin>

The thermoplastic resin constituting the retardation film of the present invention preferably has transparency and heat resistance, and preferably has a glass transition temperature of 120 ° C or more and a linear expansion coefficient of 7.0 × 10 ^-5 / ° C or less. Specific examples thereof include a cyclic olefin resin, a cellulose resin, a polycarbonate (PC), a polyarylate (PAR), a polyfluorene (PSF), a polyether oxime (PES), and a polyparaphenylene (PPP). ), polyarylene ether phosphorus oxide (PEPO), polyimine (PPI), polyether quinone imine (PEI), polyamidimide (PAI), and the like. Among these, a cyclic olefin resin and a cellulose resin are preferable, and a cyclic olefin resin is more preferable.

The cyclic olefin resin is not particularly limited, and examples thereof include a ring-opening (co)polymer of a cyclic olefin monomer having a norbornene skeleton, a hydrogenated product of a ring-opening (co)polymer, and addition (co) A copolymer of a polymer or a cyclic olefin monomer and another monomer having copolymerization property, a hydrogenated product thereof, or the like.

Specifically, for example, a ring-opened (co)polymer of a cyclic olefin monomer represented by the following formula (I') and formula (II'), a hydrogenated product of the ring-opened (co)polymer, An addition (co)polymer, an addition copolymer of a cyclic olefin monomer and an α-olefin, and the like. Among these, a hydrogenated product of a ring-opening (co)polymer is preferable, and a copolymer having a repeating unit represented by the above formula (I) is particularly preferable. The polymer may be a single polymer having a repeating unit represented by the above formula (I), or a copolymer having a repeating unit represented by the formula (I) and the following formula (II).

[Chemical 2]

[In the formula (II), E is a group independently represented by -CH=CH- or -CH ₂ CH ₂ -, and R ⁵ to R ⁸ each independently represent a hydrogen atom; a halogen atom; an oxygen atom, a sulfur atom; a linking group of a nitrogen atom or a halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; and a polar group, R ⁵ and R ⁶ may be integrated to form a divalent hydrocarbon group, and R ⁷ and R ^{8 are} also It may be integrated to form a divalent hydrocarbon group; R ⁵ or R ⁶ and R ⁷ or R ⁸ may be bonded to each other to form a carbocyclic or heterocyclic ring, and the carbocyclic or heterocyclic ring may be a monocyclic structure or a polycyclic ring. structure].

The glass transition temperature of the cyclic olefin resin is applied to the region of the film processing, and the birefringence control property is ensured at the same time. Therefore, m in the above formula (I) is preferably 1 to 5, more preferably 1 to 3, most preferably 1~2, p should be 0~4, more preferably 0~2, most preferably 0~1. Further, the number of carbon atoms of R ¹ to R ⁴ is preferably from 1 to 25, more preferably from 1 to 20, most preferably from 1 to 10. Further, the number of carbon atoms of R ⁵ to R ⁸ in the above formula (II) is preferably from 1 to 25, more preferably from 1 to 20.

Method for producing cyclic olefin resin

The cyclic olefin resin of the present invention has a repeating unit represented by the above formula (I) and a repeating unit represented by the above formula (II) as needed.

The repeating unit represented by the above formula (I) is subjected to ring (co)polymerization and is derived from a cyclic olefin monomer represented by the following formula (I').

[Chemical 3]

(In the formula (I'), m and R ¹ to R ⁴ are the same as the above formula (I)).

In the formula (I) or the formula (I'), the polar group may, for example, be a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a carbonyloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a cyano group or a decylamino group. An anthracene, a triorganomethoxy group, a triorganomylalkyl group, an amine group, a decyl group, an alkoxycarbenyl group, a sulfonyl group, a carboxyl group, and the like. More specifically, the alkoxy group may, for example, be a methoxy group or an ethoxy group; and the carbonyloxy group may, for example, be an alkylcarbonyloxy group such as an ethylene oxide or a propyloxy group, or a benzamidineoxy group or the like. The arylcarbonyloxy group; the alkoxycarbonyl group may, for example, be a methoxycarbonyl group or an ethoxycarbonyl group; and the aryloxycarbonyl group may, for example, be a phenoxycarbonyl group, a naphthyloxycarbonyl group, a decyloxycarbonyl group or a biphenyloxy group. The carbonyl group and the like; the triorganomethoxy group may, for example, be a trimethyl decyloxy group or a triethyl decyloxy group; and the triorganomethyl sulfonyl group may, for example, be a trimethylmethyl decyl group or a triethyl methoxyalkyl group; The amine group may, for example, be a first-order amine group, and the alkoxycarbenyl group may, for example, be a trimethoxycarbenyl group or a triethoxycarbenyl group.

The halogen atom may, for example, be a fluorine atom, a chlorine atom or a bromine atom.

Examples of the hydrocarbon group having 1 to 10 carbon atoms include an alkyl group such as a methyl group, an ethyl group or a propyl group; a cycloalkyl group such as a cyclopentyl group or a cyclohexyl group; an alkenyl group such as a vinyl group, an allyl group or a propylene group; .

Further, the substituted or unsubstituted hydrocarbon group may be directly bonded to the ring structure or may be bonded via a linker. Examples of the linking group include a divalent hydrocarbon group having 1 to 10 carbon atoms (for example, -(CH ₂ ) _m - (wherein m is an integer represented by an integer of 1 to 10); and oxygen, nitrogen, and a linking group of sulfur or hydrazine (for example, a carbonyl group (-CO-), an oxycarbonyl group (-O(CO)-), a sulfo group (-SO ₂ -), an ether bond (-O-), a thioether bond ( -S-), imine (-NH-), guanamine bond (-NHCO-, -CONH-), decane bond (-OSi(R ₂ )- (wherein R is methyl, ethyl The alkyl group or the like may also be a linking group containing a plurality of these.

The cyclic olefin-based monomer (I') is specifically exemplified by the following compounds.

Tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, pentacyclic [6.5.1.1 ^3,6 .0 ^2,7 .0 ^9,13 ]-4-pentadecene , 8-methyltetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-ethyltetracycline [4.4.0.1 ^2,5 .1 ^7,10 ]-3- Dodecene, 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-isopropoxycarbonyl Tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-n-butoxycarbonyltetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-12 Carbene, 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-butyl Oxycarbonyl tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-cyanotetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-12 Carbene, 8-cyano-8-methyltetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]- 3-dodecene, 8-ethylenetetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-phenyltetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-fluorotetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-fluoromethyltetracycline [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-trifluoromethyl Tetracyclic [4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-pentafluoroethyltetracycline [4.4.0.1 ^2,5 .1 ^7,10 ]-3-12 Carbene, 8,8-difluorotetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8,9-difluorotetracycline [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-double (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- trifluoro-tetracyclo [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) Base) tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8,8,9-trifluoro-9-trifluoromethyltetracycline [4.4.0.1 ^2,5 . 1 ^7,10] -3-dodecene, 9-trifluoromethyl-methoxy-8,8,9- trifluoro-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] -3- dodecene Alkene, 8,8,9-trifluoro-9-pentafluoropropoxytetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-fluoro-8-pentafluoro Base-9,9-bis(trifluoromethyl)tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8,9-difluoro-8-heptafluoroisopropyl -9-trifluoromethyltetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene, 8-chloro-8,9,9-trifluoromethyltetracyclo[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-a -8-(2,2,2-trifluoroethoxycarbonyl)tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene

These may be used alone or in combination of two or more.

In the present invention, it is preferred that the repeating unit represented by the above formula (I) has a polar group, and the polar group is preferably a group represented by the following formula (III). That is, at least one of the repeating unit represented by the above formula (I) or the cyclic olefin system represented by the above formula (I'), preferably R ¹ to R ⁴ , is represented by the following formula (III) The basis.

-(CH ₂ ) _P COOR'...(III)

(In the formula (III), p is an integer of 0 or 1 to 5, and R' is a hydrocarbon group having 1 to 15 carbon atoms).

In the above formula (III), the smaller the value of p, the smaller the carbon number of R', and the higher the glass transition temperature of the obtained copolymer, the better the heat resistance, which is preferable. That is, p is generally an integer of 0 or 1 to 5, preferably 0 or 1, and R is generally a hydrocarbon group having 1 to 15 carbon atoms, but is preferably an alkyl group having 1 to 3 carbon atoms.

Further, in the above formula (I) or (I'), when the carbon atom bonded by the polar group represented by the above formula (III) is further alkyl-bonded, the heat resistance and water absorption of the obtained copolymer are sought ( The balance of wetness is good. Further, the number of carbon atoms of the alkyl group is preferably from 1 to 5, more preferably from 1 to 2, particularly preferably 1.

The repeating unit represented by the above formula (II) is derived from the cyclic olefin monomer (II) represented by the following formula (II') by ring-opening copolymerization.

[Chemical 4]

(In the formula (II'), R ⁵ to R ⁸ are the same as the above formula (II)).

Specific examples of such a cyclic olefin-based monomer include the following compounds.

Tricyclo[4.3.0.1 ^2,5 ]癸-3,7-diene (dicyclopentadiene), bicyclo[2.2.1]hept-2-ene (norbornene), bicyclo[2.2.1]g -2,5-diene, 5-methylbicyclo[2.2.1]hept-2-ene, 5-ethylbicyclo[2.2.1]hept-2-ene, 5-propylbicyclo[2.2.1] Hept-2-ene, 5-butylbicyclo[2.2.1]hept-2-ene, 5-pentylbicyclo[2.2.1]hept-2-ene, 5-hexylbicyclo[2.2.1]hept-2 - alkene, 5-heptylbicyclo[2.2.1]hept-2-ene, 5-octylbicyclo[2.2.1]hept-2-ene, 5-nonylbicyclo[2.2.1]hept-2-ene , 5-mercaptobicyclo[2.2.1]hept-2-ene, 5-undecylbicyclo[2.2.1]hept-2-ene, 5-dodecylbicyclo[2.2.1]hept-2 - alkene, 5-tridecacarbylbicyclo[2.2.1]hept-2-ene, 5-tetradecylbicyclo[2.2.1]hept-2-ene, 5-pentadecylbicyclo[2.2.1 Hept-2-ene, 5-hexadecylbicyclo[2.2.1]hept-2-ene, 5-heptadecenylbicyclo[2.2.1]hept-2-ene, 5-octadecylbicyclo [2.2.1] Hept-2-ene, 5-nonadenobicyclo[2.2.1]hept-2-ene, 5-epicocarbylbicyclo[2.2.1]hept-2-ene, 5-benzene Bicyclo[2.2.1]hept-2-ene, 5-cyanobicyclo[2.2.1]hept-2-ene, 5-methoxycarbonylbicyclo[2.2.1]hept-2-ene, 5-B Oxycarbonylbicyclo[2.2.1]hept-2-ene, 5-a Carbocarbonyl-5-methylbicyclo[2.2.1]hept-2-ene, 5-ethoxycarbonyl-5-methylbicyclo[2.2.1]hept-2-ene, 5-cyano-5- Bicyclo[2.2.1]hept-2-ene, 5-ethylenebicyclo[2.2.1]hept-2-ene spiro[芴-9,8'-tricyclo[4.3.0.1 ^2,5 ][3 ] Terpene].

These may be used alone or in combination of two or more. In the present invention, tricyclo[4.3.0.1 ^2,5 ]indole-3,7-diene and bicyclo[2.2.1]hept-2-ene are preferably used.

The cyclic olefin resin of the present invention can be produced by subjecting one or more kinds of the cyclic olefin monomer (I') and the cyclic olefin monomer (II') to ring-opening copolymerization. The cyclic olefin resin of the present invention is preferably one or more selected from the group consisting of 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ]-3-dodecene. And a copolymer composed of tricyclo[4.3.0.1 ^2,5 ]癸-3,7-diene and bicyclo[2.2.1]hept-2-ene.

In the present invention, the copolymerization ratio of the cyclic olefin monomer (the compound represented by the formula (I')) and the cyclic olefin monomer (the compound represented by the formula (II')) is such When the total amount is 100 parts by weight, the cyclic olefin monomer (II') is usually from 0 to 40 parts by weight, preferably from 3 to 30 parts by weight. When the copolymerization ratio of the cyclic olefin monomer (II') exceeds 30 parts by weight, the glass transition temperature may be lowered to lower the heat resistance stability of each of the properties of the film such as a phase difference or a size. Moreover, the slidability and phase difference developability of the molded article, film or sheet obtained when the amount is less than 3 parts by weight are lowered.

In the present invention, in addition to the cyclic olefin monomers (I') and (II'), a small amount of other cyclic olefin monomers may be used in the range which does not impair the object of the present invention. The other monomer to be polymerized is a copolymerization raw material monomer, and the cyclic olefin resin of the present invention may contain a repeating unit other than the repeating unit represented by the above formulas (I) and (II). Such a repeating unit is, for example, a cycloolefin monomer such as cyclobutene, cyclopentene, cycloheptene or cyclooctene, which is ring-opened together with the above cyclic olefin monomers (I') and (II'). Aggregate to form. Further, the main chain of polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-nonconjugated diene copolymer, polynorbornene or the like may also have olefinic unsaturation. In the presence of a bond-unsaturated hydrocarbon-based polymer or the like, the cyclic olefin-based monomers (I') and (II') are formed by ring-opening copolymerization, and when such a repeating unit is present, the present invention can be improved. The tendency of the copolymer to withstand impact.

However, in the present invention, it is preferred to carry out copolymerization using only the cyclic olefin monomers (I') and (II'). That is, the cyclic olefin resin of the present invention may be other than the repeating unit represented by the above formulas (I) and (II), and may have other repeating units in the range which does not impair the object of the present invention, but preferably does not have Repeating units other than the repeating units represented by the above formulas (I) and (II).

The ring-opening copolymer in which only the cyclic olefin monomer is ring-opened and copolymerized has an olefinic unsaturated bond in its molecule, and since it has a problem of heat-resistant coloring or the like, it is preferable to add such an olefinic unsaturated bond. Hydrogen, but such a hydrogenation reaction can also be applied to a known method.

For example, a catalyst, a solvent, a temperature condition, etc. described in the Unexamined-Japanese-Patent No. No. Nos. The ring-opening polymerization reaction and the hydrogenation reaction are carried out.

The hydrogenation rate of the olefinic unsaturated bond is generally 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 99 mol% or more. In the hydrogenation reaction of the present invention, when the cyclic olefin resin of the present invention has an aromatic group in the case of an olefinic unsaturated bond in the molecule, such an aromatic group is also in optical properties such as refractive index or heat resistance. Sexuality can advantageously work and therefore does not have to be hydrogenated.

The molecular weight of the cyclic olefin resin of the present invention is usually 3 × 10 ³ to 5 × 10 ⁵ , preferably ⁵ , in terms of polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC). ×10 ³ to 3 × 10 ⁵ , more preferably 1 × 10 ⁴ to 2 × 10 ⁵ , and the weight average molecular weight (Mw) in terms of polystyrene is generally 5 × 10 ³ to 1 × 10 ⁶ , preferably 1 ×10 ⁴ to 5 × 10 ⁵ , more preferably in the range of 2 × 10 ⁴ to 4 × 10 ⁵ .

When the molecular weight is too small, the strength of the obtained film may be low, or the phase difference developability during elongation processing may be lowered. Further, when the molecular weight is too large, the solution viscosity or the melt viscosity may become too high and the productivity or workability of the copolymer of the present invention may deteriorate.

Further, the molecular weight distribution (Mw/Mn) of the cyclic olefin resin of the present invention is generally from 1.5 to 10, preferably from 2 to 7, more preferably from 2 to 5.

The saturated water absorption of the cyclic olefin resin of the present invention at 23 ° C is usually 0.05 to 1% by weight, preferably 0.07 to 0.8% by weight, more preferably 0.1 to 0.7% by weight. When the saturated water absorption ratio of the cyclic olefin resin of the present invention is within the above range, the optical properties, transparency, phase difference, and phase difference uniformity or dimensional accuracy of the obtained film are excellent even in high temperature and high humidity conditions. It can also be stably maintained, and because it has excellent adhesion and adhesion to other materials, it does not cause peeling during use, and compatibility with additives such as antioxidants is also good, so the types of additives And the degree of freedom in the selection of the added amount becomes large.

When the saturated water absorption ratio is less than 0.05% by weight, the obtained film has a low adhesion or adhesion to other materials, and is likely to be peeled off during use, and the amount of additives such as an antioxidant is limited. Further, when the saturated water absorption ratio exceeds 1% by weight, changes in optical characteristics or dimensional changes are likely to occur due to water absorption.

Here, the saturated water absorption rate is determined in accordance with ASTM D570 by measuring the weight increase by immersing in water at 23 ° C for one week.

The glass transition temperature (Tg) of the cyclic olefin resin of the present invention is generally 70 to 250 ° C, preferably 90 to 200 ° C, more preferably 100 to 180 ° C, and has excellent heat resistance when the Tg is 120 ° C or higher. , so good. When the Tg is less than 90 ° C, the heat distortion temperature is lowered, so that there is a problem in heat resistance, and a problem arises in that the change in optical characteristics due to the temperature in the obtained film becomes large. Further, when the Tg exceeds 200 ° C, the processing temperature during the stretching process becomes too high, and the copolymer of the present invention may be thermally deteriorated, or the productivity or workability may be deteriorated.

In the present specification, the Tg of a thermoplastic resin (for example, a cyclic olefin resin) is a maximum differential heat curve obtained by using a differential scanning calorimeter (DSC) at a temperature increase rate of 20 ° C /min and a nitrogen atmosphere. The peak temperature (point A) and the maximum peak temperature to -20 °C (point B) are plotted on the differential scanning heat curve, the tangent on the baseline with point B as the starting point and the tangent with point A as the starting point. Find it by intersection.

Polymerization catalyst

For the catalyst used in the production of the cyclic olefin resin of the present invention, for example, a catalyst described in Olefin Metathesis and Metathesis Polymerization (K. J. IVIN, J. C. MOL, Academic Press 1997) is preferably used. Such a catalyst may, for example, be (i) (a) at least one compound selected from the group consisting of W, Mo, Re, V and Ti; (b) an alkali metal element (for example, Li, Na, R), an alkaline earth metal element (for example) a compound of Mg, Ca), a Group 12 element (for example, Zn, Cd, Hg), a Group 13 element (for example, B, Al), a Group 14 element (for example, Si, Sn, Pd), and the like, and is selected from at least A metathesis catalyst composed of a combination of at least one of the element-carbon bond or the element-hydrogen bond. In order to increase the activity of the catalyst, it may be added to the (c) additive described later.

Specific examples of the component (a) it may be as _{WCl 6, MoCl 5, ReOCl 3} , VOCl 3, TiCl _4, etc. Compound Laid-Open No. 1-240517 Publication describes the example. These may be used alone or in combination of two or more.

Specific examples of the component (b) include, for example, 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 A compound described in JP-A No. 1-240517, such as AlCl ₂ , methylaluminoxane or LiH. These may be used alone or in combination of two or more.

For the additive of the component (c), for example, an alcohol, an aldehyde, a ketone, an amine or the like can be suitably used. Further, a compound described in JP-A No. 1-240517 can be used. These may be used alone or in combination of two or more.

The amount of the metathesis catalyst in which the component (a) or the like is combined is such that the molar ratio of the component (a) and the wholly monomer "(a) component: all monomer" is generally 1:500 to 1: The range of 500000 should be in the range of 1:1000~1:100000. Further, the ratio of the component (a) to the component (b) is "(a): (b)", and the metal atom (mol) ratio is generally 1:1 to 1:50, preferably 1:2 to 1: 30 range. When the above (c) additive is added to the metathesis catalyst, the ratio of the component (a) to the component (c) is generally "0.00:1 to 15:1", and the molar ratio of "(c):(a)" is preferably 0.005:1 to 15:1. It is in the range of 0.05:1 to 7:1.

Further, in the case of other catalysts, (ii) a transition metal-carbene complex or a metallocyclobutane complex according to Group 4 to Group 8 of the periodic table may be used. Metathesis catalyst.

Specific examples of the catalyst (ii) include, for example, W(=N-2,6-C ₆ H ₃ ⁱ Pr ₂ )(=CH ^tert Bu)(O ^tert Bu) ₂ , Mo(=N-2,6 -C ₆ H ₃ ⁱ Pr ₂ )(=CH ^tert Bu)(O ^tert Bu) ₂ , Ru(=CHCH=CPh ₂ )(PPh ₃ ) ₂ Cl ₂ , Ru(=CHPh ₂ )[P(C ₆ H ₁₁ ) ₃ ] ₂ Cl ₂ , Ru(=CHPh)[P(C ₆ H ₁₁ ) ₃ ] ₂ Cl ₂ and the like. These may be used alone or in combination of two or more.

The amount of the catalyst (ii) used is "catalyst (ii): all monomer", and the molar ratio is generally in the range of 1:500 to 1:50000, preferably in the range of 1:100 to 1:10000.

Further, it may be used even if the above-described catalysts (i) and (ii) are combined.

The adjustment of the molecular weight of the copolymer used in the present invention may be carried out by adjusting the polymerization temperature, the type of the catalyst, the kind of the solvent, etc., but it is preferable to coexist the molecular weight modifier in the reaction system of ring-opening copolymerization. To make adjustments. The molecular weight modifier is preferably, for example, an α-olefin such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene or 1-decene. And styrene, among these, 1-butene and 1-hexene are particularly preferable. These molecular weight modifiers may be used alone or in combination of two or more. The molecular weight regulator is used in an amount of from 0.005 to 0.6 mol, preferably from 0.02 to 0.5 mol, per monomer.

The solvent used in the ring-opening copolymerization reaction (that is, the monomer, the ring-opening polymerization catalyst, and the catalyst for dissolving the molecular weight modifier) may, for example, be pentane, hexane, heptane, octane or hydrazine. Alkane such as alkane or decane; cycloalkane such as cyclohexane, cycloheptane, cyclooctane, decahydronaphthalene or norbornane; benzene, toluene, xylene, ethylbenzene, cumene, etc. Aromatic hydrocarbon; a compound such as chlorobutane, bromohexane, dichloromethane, dichloroethane, hexamethylene dibromide, chlorobenzene, chloroform, tetrachloroethylene or the like; a halogenated alkane; A saturated carboxylic acid ester such as ethyl ester, n-butyl acetate, isobutyl acetate or methyl propionate; or an ether such as dibutyl ether, tetrahydrofuran or dimethoxyethane. Among these, aromatic hydrocarbons are preferred. These may be used alone or in combination of two or more. The solvent used in the ring-opening polymerization reaction is usually in a ratio of 1:1 to 10:1 by weight of the solvent: all monomer. It is preferably 1:1 to 5:1.

The temperature of the monomer solution when the catalyst is added is preferably 30 to 200 ° C, more preferably 50 ° C to 180 ° C. When the temperature is less than 30 ° C, the yield of the polymer may be lowered, and when it exceeds 200 ° C, it may be difficult to control the molecular weight.

The reaction time in the ring-opening copolymerization reaction is usually 0.1 to 10 hours, but it is preferably 0.1 to 9 hours, more preferably 0.1 to 8 hours.

The ring-opening copolymer in which only the cyclic olefin monomer is ring-opened and copolymerized has an olefinic unsaturated bond in its molecule, and since it has a problem of heat-resistant coloring or the like, it is preferable to add such an olefinic unsaturated bond. hydrogen. The method of adding hydrogen, preferably the hydrogenation rate is as described above.

<additive>

The thermoplastic resin of the present invention can be formulated with various additives as needed. For example, in order to improve oxidation stability and prevent coloration and deterioration, an antioxidant selected from the group consisting of a phenolic antioxidant, a lactone antioxidant, a phosphorus antioxidant, and a sulfur antioxidant may be formulated.

The antioxidant is formulated in a ratio of 0.001 to 5 parts by weight per 100 parts by weight of the polymer. Specific examples of the antioxidant include, for example,

1) 2,6-di-third-based 4-methylphenol, 4,4'-thiobis-(6-t-butyl-3-methyl-phenyl), 1,1-bis(4- Hydroxyphenyl)cyclohexane, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), tetra[methylene-3-(3,5-di-t-butyl) 4-hydroxyphenyl)propionate]methane, 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid stearate, 2,5-di-t-butylhydroquinone And a phenolic antioxidant or a hydroquinone antioxidant such as pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)]propionate.

2) bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite, tetra (2,4) -di-tert-butyl-5-methylphenyl) 4,4'-biphenylene diphosphinate, 3,5-di-t-butyl-4-hydroxyphenylmethylphosphonic acid-diethyl Base ester, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tris(4-methoxy-3,5-diphenyl)phosphite and tris(nonylphenyl) Phosphorus-based secondary antioxidant such as phosphate ester, and 3) sulfur-based secondary antioxidant such as dilauryl-3,3'-thiodipropionate or 2-hydrothiobenzimidazole.

Further, a flame retardant may be formulated in the thermoplastic resin of the present invention. As the flame retardant, a known one may be used, and examples thereof include a halogen-based flame retardant, a rhodium-based flame retardant, a phosphate-based flame retardant, and a metal hydroxide. Among them, a small amount of the matching effect can be exhibited, and the phosphate ester-based flame retardant can be deteriorated to the minimum of water absorption, low dielectric property and transparency, and more preferably 1,3-bis(phenylphosphoryl)benzene. 1,3-bis(diphenylphosphoryl)benzene, 1,3-bis[di(alkylphenyl)phosphate]benzene, 1,3-bis[bis(2',6'-dimethylbenzene) Phosphate]phenyl, 1,3-bis[bis(2',6'-diethylphenyl)phosphate]benzene, 1,3-bis[bis(2',6'-diisopropyl) Phenyl)phosphoryl]benzene, 1,3-bis[bis(2',6'-dibutylphenyl)phosphate]benzene, 1,3-bis[di(2'-tert-butylphenyl) Phosphate]benzene, 1,3-bis[bis(2'-isopropylphenyl)phosphate]benzene, 1,3-bis[bis(2'-methylphenyl)phosphate]benzene, 1 , 4-bis(diphenylphosphoryl)benzene, 1,4-bis[bis(2',6'-dimethylphenyl)phosphate]benzene, 1,4-bis[2(2',6 '-Diethylphenyl)phosphoryl]benzene, 1,4-bis[bis(2',6'-diisopropylphenyl)phosphate]benzene, 1,4-bis[2(2'- Tert-butylphenyl)phosphoryl]benzene, 1,4-bis[bis(2'-isopropylphenyl)phosphate]benzene, 1,4-bis[bis(2'-methylphenyl) Phosphate]benzene and 4,4'-bis[di(2",6"-dimethylphenyl) A condensed phosphate ester such as phosphate phenyl]dimethylmethane is a flame retardant. The blending amount is determined depending on the selected flame retardant and the required flame resistance, but it is preferably 0.5 to 40 parts by weight, more preferably 2 to 30 parts by weight, based on 100 parts by weight of the cyclic olefin polymer. It should be 4 to 20 parts by weight. When the amount of the flame retardant is less than 0.5 part by weight, the effect is insufficient. When the amount is more than 40 parts by weight, the transparency is deteriorated, the electrical properties such as the dielectric property are deteriorated, and the water absorption rate is increased. deterioration.

The thermoplastic resin of the present invention may contain an antioxidant, a thermal stabilizer, a photo-stabilizer, a phase difference adjuster, an ultraviolet absorber, an antistatic agent, a dispersant, a processability enhancer, etc., as needed within the scope of the effect of the invention. Chlorine trapping agent, flame retardant, crystallization nucleating agent, anti-pressure adhesive, anti-fogging agent, release agent, pigment, organic or inorganic filler, neutralizer, slip agent, decomposer, metal inerting agent, anti-proof A well-known additive such as a pollutant material, an antibacterial agent or other resin, a thermoplastic elastomer or the like.

<Original film>

The raw material film used for the production of the retardation film of the present invention can be obtained by dissolving a thermoplastic resin, preferably the above-mentioned cyclic olefin-based resin, in a suitable solvent, casting it, and forming a film and a sheet. Further, it can also be obtained by film formation by a known method such as a melt extrusion method.

The obtained raw material film is composed of a cyclic olefin resin, and is excellent in balance of optical properties such as transparency, chemical resistance, heat resistance, water resistance, and moisture resistance.

The film thickness of the original film is 100-250 pm and is 120-200 μm, and the difference between the maximum thickness and the minimum thickness of the film is 3 μm or less, preferably within 2 μm.

Further, it is preferable to use a film in which the in-plane phase difference of the light wavelength of 550 nm is 20 nm or less, preferably 0 to 15 nm, more preferably 0 to 10 nm. Further, the direction of the maximum refractive index in the plane of the film is preferably in the range of 0 ± 30 degrees with respect to the longitudinal direction of the film, and more preferably in the range of 0 ± 20 degrees.

<phase difference film>

The retardation film of the present invention comprises a film of a polarizing plate of a liquid crystal display device of the present invention, which is composed of a thermoplastic resin, and has a phase difference R0 of 20 to 150 nm, preferably 30 to 140 nm, particularly preferably 30 to 130 nm. The NZ coefficient NZ is 1.1 to 4.3, preferably 1.1 to 3.9, and particularly preferably 1.2 to 3.0. If R0 is less than 20 nm. There is a problem that the optical axis becomes non-uniform and the uniformity in the plane of the liquid crystal display element deteriorates, and if it exceeds 150 nm, the viewing angle becomes narrow. Further, if NZ is less than 1.1, there is a problem that the viewing angle is narrowed. If it exceeds 4.3, the optical axis becomes non-uniform, and the uniformity in the plane of the liquid crystal display element deteriorates.

In the present invention, the in-plane phase difference R0 and the NZ coefficient NZ of the film respectively make the maximum refractive index in the plane of the film at a light wavelength of 550 nm nx, and the refractive index in the direction perpendicular to nx in the plane of the film is ny, The refractive index in the film thickness direction is nz, and when the film thickness is d (nm), the value obtained by the formula R0 = (nx - ny) xd and the formula NZ = (nx - nz) / (nx - ny).

In the retardation film of the present invention, the direction of the maximum refractive index may be the direction of either the long direction or the wide direction of the film, but it is preferably the width direction.

Further, the polarizing plate having the retardation film of the present invention is arranged such that the liquid crystal cell is disposed on the viewer side (front side) and the back side of the liquid crystal display element, but R0 of the retardation film disposed on the observer side is R0f, When NZ is NZf, when R0 of the retardation film disposed on the back side is R0r and NZ is NZr, R0f × NZf + R0r × NZr is preferably 200 nm to 260 nm, and particularly preferably 220 nm to 240 nm. When the above value is in this range, it is possible to obtain an effect that the viewing angle in the vertical direction is 110 degrees or more and the viewing angle in the left and right direction is 150 degrees or more.

The retardation film is preferably a film roll having a width of 1,300 mm or more, more preferably 1,500 mm or more, and most preferably 2000 mm or more. Such a retardation film is continuously laminated by a roll to a roll of a film roll of a polarizer and, if necessary, an adhesive, to obtain a laminated film. Such a laminated film is further laminated with a protective film as needed, and can be suitably used as a polarizing plate.

Further, a film roll using a retardation film, a film roll with a polarizer, a film which can be used as a protective film, a film of a preferred cyclic olefin resin film (raw material film) or a film of a triacetyl cellulose film can be used. The rolls are laminated as needed by an adhesive, and the polarizing plate can be continuously produced. According to such a method, the manufacturing efficiency is good, and a polarizing plate can be manufactured.

The retardation film of the present invention is generally produced by stretching a film of a raw material of a thermoplastic resin as described later, and the optical characteristics can be controlled at a high level in the film. Specifically, the unevenness of the film in-plane retardation film R0 is preferably 2 nm or less, more preferably 1.5 nm or less, and particularly preferably 1.0 nm or less. Further, when the angle of the maximum refractive index in the plane of the film and the angle in the width direction of the film are α angles, α indicating the deviation of the optical axis is 30 or less, more preferably 25 or less, and particularly preferably 20 or less. Thus, by highly controlling the optical characteristics, a liquid crystal display element in which unevenness is not displayed and no bright spots are obtained can be obtained.

Method for manufacturing retardation film

The retardation film of the present invention may be such that the raw material film (1) is uniaxially stretched under heating in the film length direction, and then biaxially stretched in a uniaxial direction toward the film width direction, or 2) toward the film. The uniaxial extension is performed in the width direction, and is suitably manufactured.

When the raw material film is stretched, the heating temperature at the time of extension is precisely controlled in the entire extension portion of the film. For example, in the method of the above (1), the uniaxial extension in the longitudinal direction, that is, the longitudinal uniaxial extension is preferably controlled so that the temperature distribution is controlled within a set temperature of ±0.6 ° C, preferably within a set temperature of ± 0.4 ° C, preferably. It is implemented in an oven set to a temperature within ±0.2 °C.

Here, the set temperature may be an equal temperature in the entire area of the oven, or the temperature of the distribution may be set in a stepwise or gradient manner, and the actual temperature distribution in the oven and the set temperature are set when the temperature of the temperature setting distribution is set. The distribution is within ±0.6 ° C, preferably within ± 0.4 ° C, and more preferably within ± 0.2 ° C.

The setting temperature of the uniaxial stretching in the long direction is not particularly limited as long as it depends on the type of the thermoplastic resin constituting the film, the stretching ratio and the stretching speed, the thickness of the film, the desired phase difference of the stretched film, and the like, but is not particularly limited. The glass transition temperature (Tg) of the thermoplastic resin constituting the raw material film is generally in the range of (Tg - 10 ° C) to (Tg + 70 ° C), preferably (Tg ± 0 ° C) ~ (Tg + 50 ° C). The scope. In such a temperature range, no thermal deterioration of the film occurs, and no film breakage can be performed, which is preferable.

When the retardation film of the present invention is produced, the stretching ratio in the long-axis uniaxial stretching is, for example, 1.1 to 2.5 times, preferably 1.1 to 2.0 times, and particularly preferably 1.2 to 1.5 times.

The elongation speed of the uniaxial stretching in the longitudinal direction when producing the retardation film of the present invention is, for example, 2 to 100 m/min, preferably 5 to 50 m/min.

When the retardation film is produced by the above method (1), the film-based film in-plane retardation film R0 which is uniaxially elongated in the longitudinal direction is generally in the range of 100 to 400 nm, preferably 150 to 300 nm.

The unevenness of the in-plane retardation R0 in the film extending uniaxially in the longitudinal direction is generally within ±3 nm, preferably within ±2 nm, and more preferably within ±1 nm. Further, the direction of the maximum refractive index in the film surface of the film which is uniaxially stretched in the longitudinal direction is generally in the range of 0 ± 3 degrees with respect to the film length direction, preferably in the range of 0 ± 2 degrees, more preferably 0 ± 1 The range of degrees.

When the retardation film is produced by the above method (1), the film of the original material is uniaxially stretched in the longitudinal direction as described above, and then uniaxially stretched in the width direction. Further, when the retardation film is produced by the method of the above (2), the raw material film is uniaxially stretched in the width direction. By making the uniaxial extension in the width direction, that is, the horizontal uniaxial extension, the uniaxial extension in the longer direction is further performed under precise temperature control, a phase difference film which is fully homogeneous can be suitably obtained. For example, the temperature distribution of the uniaxial extension in the width direction is controlled within a set temperature of ±0.5 ° C, preferably within a set temperature of ± 0.3 ° C, and more preferably within an oven of a set temperature of ± 0.2 ° C.

Here, the set temperature of the uniaxial extension in the width direction is the same as the case of the uniaxial extension in the long direction, and may be an equal temperature in the entire area of the oven, or may be set to a temperature in a stepwise or gradient manner. When the temperature of the temperature setting distribution is set, the actual temperature distribution in the oven and the set temperature distribution are within ±0.5 ° C, preferably within ±0.3 ° C, and more preferably within ± 0.2 ° C. The set temperature of the uniaxial extension in the lateral direction may be the same as or different from the set temperature in the step of extending the uniaxial direction in the longitudinal direction.

The set temperature of the uniaxial stretching in the lateral direction is not particularly limited as long as the uniaxial stretching in the longitudinal direction, but the glass transition temperature (Tg) of the cyclic olefin resin is generally (Tg - 10 ° C) - ( The range of Tg + 70 ° C) is preferably in the range of (Tg ± 0 ° C) ~ (Tg + 50 ° C).

The stretching ratio of the uniaxial stretching in the width direction may be determined according to the desired characteristics of the optical film to be produced, but in the case of the method of the above (1), for example, it is 1.2 to 2.5 times, preferably 1.3 to 2.0 times. It is particularly preferably in the range of 1.4 to 1.7 times, and in the case of the method of the above (2), for example, 1.5 to 4 times, preferably 1.7 to 3.7 times, and particularly preferably 2 to 3.5 times.

The stretching ratio of the uniaxial stretching in the width direction is, for example, 2 to 100 m/min, preferably 5 to 50 m/min.

When the retardation film is produced by the method of the above (1), the phase difference film obtained is, for example, 1.3 to 6.0 times, preferably 1.7 to 3.0 times the stretching ratio of the raw material film. This stretching ratio is a product of the stretching ratio of the uniaxial stretching in the longitudinal direction and the stretching ratio of the uniaxial stretching in the lateral direction.

In the method for producing a retardation film, the type of the thermoplastic resin constituting the film, that is, the selection of the resin such as the polymer species, the copolymerization ratio, the molecular weight distribution, the glass transition temperature, and the like, and the long direction of the film are considered. The characteristics of the obtained retardation film can be controlled by selecting the set temperature in the oven in the steps of the shaft extension and the uniaxial stretching in the width direction, the selection of the stretching ratio and the stretching speed.

<Polarizing plate>

The polarizing plate of the present invention has the above-described retardation film and polarizer. Further, a protective film for protecting the polarizer is further provided as needed.

Polarizer

The polarizer constituting the polarizing plate of the present invention is not limited, and a film having a function as a polarizer can be used. However, it is generally used for a polarizer in which a polymer film is adsorbed to form an iodine or a dichroic dye. The polarizer constituting the polarizing plate of the present invention is preferably composed of a polyvinyl alcohol (PVA) film.

The polarizer composed of the PVA-based film is not particularly limited as long as it has a function as a polarizer, and for example, PVA obtained by uniaxially stretching in a boric acid bath after iodine is adsorbed on the PVA film is exemplified. /Iodine-based polarizing film; PVA/dye-based polarizing film obtained by uniaxial stretching after diffusion and adsorption of a direct dye of high dichroism on a PVA film; PVA/polyethylene which is formed by adsorbing iodine on a PVA film and extending to form a polyethylene structure a polarizing film; a PVA/metal polarizing film for adsorbing metals such as gold, silver, mercury, iron, etc. on a PVA film; a near-ultraviolet polarizing film for treating a PVA film with a boric acid solution containing potassium iodide and sodium thiosulfate; A surface of a PVA-based film composed of a cationically modified PVA and/or a polarizing film having a dichroic dye therein.

The method for producing a polarizer comprising a PVA-based film is not particularly limited, and examples thereof include a method of adsorbing a PVA-based film to adsorb iodide ions, and a method of stretching a PVA-based film by a dichroic dye; A method in which a PVA-based film is dyed by a dichroic dye, a method in which a dichroic dye is printed on a PVA-based film, and a method of stretching, and a method in which a PVA-based film is stretched, and a dichroic dye is printed. More specifically, iodine is dissolved in a potassium iodide solution to prepare a high-order iodide ion, and the iodide ion is adsorbed on the PVA film to be stretched, and then immersed in a 1-4% boric acid aqueous solution at a bath temperature of 30 to 40 ° C. In the method of polarizing the film, the PVA film is similarly subjected to boric acid treatment, and is extended in the uniaxial direction by about 3 to 7 times, and immersed in a 0.05 to 5% dichroic dye aqueous solution at a bath temperature of 30 to 40 ° C to adsorb the dye. A method of drying at 80 to 100 ° C for heat setting to produce a polarizing film, and the like.

Any of the polarizers of the present invention preferably has an absorption axis in the longitudinal direction (longitudinal direction). A polarizer having an absorption axis in the longitudinal direction is produced by extending a polymer film by longitudinal uniaxial stretching.

Protective film

The polarizing plate of the present invention maintains the durability or mechanical properties of the polarizer, and may also have a protective film as needed. The protective film is not particularly limited as long as it is excellent in transparency, water resistance, and low moisture absorption. For example, triethyl fluorenyl cellulose (TAC), cyclic olefin resin, and polyparaic acid can be suitably used. A film composed of an ethylene glycol resin, a polycarbonate resin, an acrylic resin, an acrylic/styrene copolymer resin, a polyolefin resin or the like. In the present invention, a film of triethylenesulfonyl cellulose (TAC) or a cyclic olefin resin is suitably used. Moreover, when a cyclic olefin type resin film is used as a protective film, it is preferable to use it without extending the said raw material film.

The polarizing plate of the present invention is preferably formed by laminating a phase difference film, a polarizer, and a protective film in sequence.

Adhesive/adhesive

In the present invention, when the retardation film and the polarizer are further protected as needed, and then the polarizing plate is produced, an adhesive or an adhesive may be used as needed. Adhesive or adhesive is adhered or subsequently, and any one of the optical properties of the obtained polarizing plate is not inhibited.

The adhesive or the adhesive agent can be suitably used as a water-based adhesive which dissolves polyvinyl alcohol (PVA) in water. Further, it is preferable to use an adhesive having a polar group or an adhesive having a polar group (hereinafter also referred to as "adhesive containing a polar group").

Examples of the polar group having a polar group-containing adhesive include an ester group such as a halogen atom and a halogen atom-containing group, a carboxyl group, a carbonyl group, a hydroxyl group, an alkyl ester group or an aromatic ester group, and an amine group or a guanamine. A group, a cyano group, an ether group, a decyl group, a carboxyalkyl ether group, a thioether group or the like. Among these, a carboxyl group, a carbonyl group, a hydroxyl group, and an ester group are preferable. Further, the adhesive containing a polar group is preferably a water-based adhesive or a water-based adhesive. The adhesive agent containing a polar group suitably used for sticking a specific resin film is an aqueous dispersion of an acrylate type polymer, for example.

The acrylate-based polymer constituting the polar group-containing adhesive can be obtained by subjecting a monomer composition containing an acrylate and a polar group-containing monomer to polymerization treatment. Here, examples of the acrylate include ethyl acrylate, propyl acrylate, cyclohexyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. Further, the polar group having a polar group may, for example, be an ester group, an amine group or an anthracene such as a halogen atom and a halogen atom-containing group, a carboxyl group, a carbonyl group, a hydroxyl group, an alkyl ester group or an aromatic ester group. An amine group, a cyano group, an ether group, a decyl group, a carboxyalkyl ether group, a thioether group or the like. Among these, a carboxyl group, a carbonyl group, a hydroxyl group, and an ester group are preferable, and a hydroxyl group and a carboxyl group are particularly preferable. Specific examples of the preferred polar group-containing monomer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylic acid, methacrylic acid, and the like. The ratio of the acrylate to be synthesized to the acrylate monomer to the monomer having a polar group is preferably from about 0.5 to 15 parts by weight based on 100 parts by weight of the acrylate polymer.

Further, a diene monomer such as divinylbenzene is preferably used as the monomer to be synthesized for the synthesis of the acrylate polymer. The acrylate-based polymer obtained by subjecting a composition containing an acrylate, a polar group-containing monomer, and a diene monomer to a polymerization treatment can form a high-strength adhesive layer. Here, the amount of the diene monomer used is preferably from 0 to 10 parts by weight based on 100 parts by weight of the acrylate polymer. If the amount of the diene monomer used exceeds 10 parts by weight, the adhesive layer or the adhesive layer may become hard.

Examples of the polymerization method for obtaining the acrylate-based polymer include an emulsion polymerization method, a state turbid polymerization method, and a solution polymerization method. In addition, when a nonpolar solvent such as toluene or xylene is used as the polymerization solvent, when the obtained adhesive is used, it is liable to cause a deviation between the polarizer and the optical film of the adherend, which is not preferable.

The molecular weight of the acrylate-based polymer constituting the polar group-containing adhesive is preferably 5,000 to 500,000, more preferably 10,000 to 200,000, and more preferably 10,000 to 200,000 in terms of polystyrene-equivalent number average molecular weight (Mn) measured by GPC analysis. (Mw) should be 15000~1000000, most preferably 20,000~500000, and its molecular weight distribution (Mw/Mn) should be 1.2~5, more preferably 1.4~3.6.

A crosslinking agent such as isocyanate or butylated melamine, an ultraviolet absorber or the like may be added to the binder containing a polar group used in the present invention. Among them, the crosslinking agent added to the binder containing a polar group is generally carried out before the application of the polar group-containing adhesive.

Method for manufacturing polarizing plate

The polarizing plate of the present invention is preferably one surface of a polarizer composed of a PVA-based film or the like, which is bonded to a retardation film by using an adhesive or an adhesive, and then heated and pressure-bonded. More preferably, the phase difference is formed on one surface of the polarizer, and the protective film is bonded to each other on the opposite side of the polarizer by using an adhesive or an adhesive, and then heated and pressure-bonded.

In the production of the polarizing plate, the two are bonded to each other such that the direction of the maximum refractive index in the film surface of the retardation film is perpendicular to the absorption axis of the polarizer.

<Liquid crystal display element>

The liquid crystal display element of the present invention has the above-described polarizing plate, and generally has a TN mode liquid crystal display element having a structure in which two liquid crystal cells are sandwiched by a polarizing plate. The TN mode liquid crystal display element has a display element using a liquid crystal cell of a TN type liquid crystal.

For example, when the liquid crystal display device of the present invention has two sequential retardation films, a polarizer, and a polarizing plate for protecting the film, it is preferable to adopt a structure in which the two sides of the liquid crystal cell are respectively opposite to the phase difference film side surface of the polarizing plate. . As the adhesion between the liquid crystal cell and each of the polarizing plates, the above-mentioned adhesive or adhesive which can be used for the production of the polarizing plate can be used. Further, an adhesive layer is further provided in advance on the surface of the liquid crystal cell of each of the polarizing plates, whereby the polarizing plate and the liquid crystal cell can be connected.

The liquid crystal display element of the present invention controls optical performance highly on the entire surface, and is uniform even in a wide panel. Therefore, it can be suitably used for a TN mode liquid crystal monitor or the like having a large display.

The liquid crystal display device of the present invention has the above-described polarizing plate and has excellent display performance, and the viewing angle is preferably 110° or more from the top, bottom, left and right, and more preferably 120° or more.

[Examples]

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the examples. Further, each trait is measured or evaluated as follows.

(1) Method for measuring R0 and maximum refractive index direction

"KOBRA-21ADH" manufactured by Oji Scientific Instruments Co., Ltd. was used to measure the phase differences R0 and NZ in the film surface of the optical film.

(2) NZ coefficient

The NZ coefficient of the optical film (phase difference film) is measured by "KOBRA-21ADH" manufactured by Oji Scientific Instruments Co., Ltd., and the refractive index nx in the X-axis direction of the optical film, the refractive index y in the Y-axis direction, and the Z-axis. The refractive index nz of the direction is obtained by the following formula.

NZ=(nx-nz)/(nx-ny)

(2) Polarization of polarizing plate

The polarizing degree of the polarizing plate was measured by incident on the adhesive side of the optical film using V-7300 manufactured by JASCO Corporation.

(3) Determination of contrast of liquid crystal display elements

Using "EZ contrast-XL88" manufactured by ELDIM Co., Ltd., the brightness, viewing angle, and contrast of the liquid crystal display element were measured in a dark room having an illuminance of 11 x or less.

(4) Glass transition temperature (Tg)

Using a DSC 6200 manufactured by Seiko Instruments, the temperature increase rate was measured at 20 ° C per minute under a nitrogen stream. The Tg system plots the maximum peak temperature of the differential scanning heat (point A) and the maximum peak temperature to -20 °C (point B) on the differential scanning heat curve, using the point B as the starting point and the tangent on the baseline. It is obtained by the intersection of the tangent of the point A as the starting point.

(5) Hydrogenation rate

For the nuclear magnetic resonance spectrometer (NMR), AVANCE 500 manufactured by Bruker Co., Ltd. was used, and the solvent was measured to determine ¹ H-NMR using d-chloroform. The hydrogenation ratio was calculated by calculating the composition of the monomer from the integrated values of the vinyl groups of 5.1 to 5.8 ppm, the methoxy group of 3.7 ppm, and the aliphatic protons of 0.6 to 2.8 ppm.

(6) Weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn)

Gel permeation chromatography (HLC-8220 GPC manufactured by Tosoh Co., Ltd., Guard Colume H _XL -H, TSK gel G7000 H _XL , TSK gel GMH _XL 2, TSK gel G2000 H, manufactured by Tosoh Co., Ltd.) _XL , sequentially connected, solvent: tetrahydrofuran, flow rate: 1 ml/min, sample concentration: 0.7 to 0.8% by weight, injection amount: 70 μL, measurement temperature: 40 ° C, detector: RI (40 ° C), standard substance: Tosoh The TSK standard polystyrene (manufactured by (Stock)) was measured for a weight average molecular weight (Mw) and a molecular weight distribution (Mw/Mn). Further, the Mn is a number average molecular weight.

(7) Amount of residual solvent

The sample was dissolved in dichloromethane, and the obtained solution was analyzed using the obtained solution (GC-7A manufactured by Shimadzu Corporation).

(8) logarithmic viscosity

The measurement was carried out using a Ubellode type viscometer in chloroform (sample concentration: 0.5 g/dl) at 30 °C.

(9) Saturated water absorption rate

The sample was immersed in water at 23 ° C for one week in accordance with ASTM D570, and the change in weight before and after immersion was measured.

(10) Total light transmittance, haze

It was measured using a haze meter (HGM-2DP type) manufactured by Suga Test Machine Co., Ltd.

<11><Damp heat test>

After the polarizing plate having the adhesive layer was bonded to the glass for LCD, it was stored in an environment of a temperature of 85 ° C and a relative humidity of 85% for 500 hours, and then the degree of polarization was measured. The value of the degree of change in the degree of polarization of the degree of polarization before and after the endurance test shown by the following formula was evaluated by the following criteria.

<12><dry heat test>

After the polarizing plate having the adhesive layer was bonded to the glass for LCD, it was stored in an environment of a temperature of 95 ° C for 500 hours, and then the degree of polarization was measured. The value of the degree of change in the degree of polarization of the degree of polarization before and after the endurance test shown by the following formula was evaluated by the following criteria.

Benchmark

◎: The amount of change in the degree of polarization is less than 0.5%.

○: The amount of change in the degree of polarization is 0.5% or more, which is less than 2.0%.

×: The amount of change in the degree of polarization is 2.0% or more

[Amount of change in polarization degree] = (1 - [Polarization degree after test] / [Initial polarization degree] × 100 (%)

[Synthesis Example 1] (Manufacture of cyclic olefin resin A)

Using 8-methyl-8-methoxycarbonyltetracyclo[4.4.0.1 ^2.5 .1 ^7.10 ]-3-dodecene (DNM) 225 parts with bicyclo [2.2.1] hept-2-ene (NB) 25 parts of the monomer, 27 parts of 1-hexene (molecular weight modifier) and 750 parts of toluene (solvent for ring-opening polymerization) were fed together in a nitrogen-substituted reaction vessel, and the solution was heated to 60 °C. Then, 0.62 parts of a toluene solution (1.5 mol/liter) of triethylaluminum was added to the solution in the reaction vessel, and tungsten hexachloride modified with a third butanol and methanol (third butanol: methanol: tungsten) was added. = 0.35 mol: 0.3 mol: 1 mol) Toluene solution (concentration: 0.05 mol/liter) 3.7 parts was used as a polymerization catalyst, and the solution was heated and stirred at 80 ° C for 3 hours to carry out ring-opening polymerization to obtain a ring-opening polymer solution. The polymerization conversion ratio in this polymerization reaction was 97%.

1000 parts of the ring-opening polymer solution obtained in this way was fed into an autoclave, and 0.12 parts of RuHCl(CO)[P(C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening polymer solution, and the pressure was 100 kg of hydrogen. /cm ² , and the reaction temperature was 165 ° C under heating and stirring for 3 hours to carry out a hydrogenation reaction.

After cooling the obtained reaction solution (hydrogenated polymer solution), the hydrogen pressure was released. This reaction solution was poured into a large amount of methanol to separate and recover the coagulum, and dried to obtain a hydrogenated polymer (hereinafter referred to as "resin A").

The hydrogenation rate measured by ¹ H-NMR of the resin A obtained in this manner was 99.9%, and the Tg measured by the DSC method was 130 ° C, and the Mn in terms of polystyrene measured by the GPC method was 20,800, and the Mw was 62,000. And Mw/Mn was 3.00, the saturated water absorption at 23 ° C was 0.21%, and the logarithmic viscosity in chloroform at 30 ° C was 0.51 dl / g.

[Synthesis Example 2] (Production of cyclic olefin resin B)

71 parts of DNM, 15 parts of dicyclopentanyl (DCP) and 1 part of NB were used as monomers, and 18 parts of 1-hexene of the molecular weight modifier and 200 parts of toluene were fed together in a nitrogen-substituted reaction vessel and heated to 100 ° C.

Further, 0.005 parts of triethylaluminum and 0.005 parts of methanol-modified WCl ₆ (anhydrous methanol: PhPOCl ₂ :WCl ₆ =103:630:427 by weight) were added, and the reaction was carried out for 1 minute, and then 10 parts of DCP and 3 parts of NB were added. Further addition was carried out for 5 minutes, and further, the reaction was carried out for 45 minutes to obtain a copolymer of DNM/DCP/NB = 69.77/26.01/4.23 (wt%).

Then, the solution of the obtained copolymer was placed in an autoclave, and further, 200 parts of toluene was added. Next, 1 part of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate as a reaction modifier was added to the hydrogenation catalyst RuHCl(CO)[P(C) ₆ H ₅ )] ₃ 0.006, after superheating to 155 ° C, hydrogen was introduced into the reactor to a pressure of 10 MPa. Thereafter, the pressure was maintained at 10 MPa, and the reaction was carried out at 165 ° C for 3 hours. After the completion of the reaction, 100 parts by weight of toluene, 3 parts by weight of distilled water, 0.72 parts by weight of lactic acid, and 0.00214 parts by weight of hydrogen peroxide were added, and the mixture was heated at 60 ° C for 30 minutes. Thereafter, 200 parts by weight of methanol was added, and the mixture was heated at 60 ° C for 30 minutes, and further cooled to 25 ° C to separate into two layers. 500 parts by weight of the supernatant was removed, 350 parts by weight of toluene and 3 parts by weight of water were added, and the mixture was heated at 60 ° C for 30 minutes. Thereafter, 240 parts by weight of methanol was added, and the mixture was heated at 60 ° C for 30 minutes, and then cooled to 25 ° C to separate. In 2 layers. 500 parts by weight of the supernatant was removed, 350 parts by weight of toluene and 3 parts by weight of water were added, and the mixture was heated at 60 ° C for 30 minutes. Thereafter, 240 parts by weight of methanol was added, and the mixture was heated at 60 ° C for 30 minutes, and then cooled to 25 ° C to separate. In 2 layers. Finally, 500 parts by weight of the supernatant liquid was removed, and 500 parts by weight of the supernatant liquid was removed, and the remaining polymer solution was filtered using respective filters of 2.0 μm, 1.0 μm, and 0.2 μm. Thereafter, the solid content of the polymer was concentrated to 55%, and the solvent was removed at 250 ° C, 4 torr, and residence time for 1 hour, and passed through a polymer filter of 10 μm to obtain a copolymer (hereinafter referred to as "resin B"). .

The hydrogenation rate measured by ¹ H-NMR of the resin B obtained in this manner was 99.9%, and the Tg measured by the DSC method was 131 ° C, and the Mn in terms of polystyrene measured by the GPC method was 16,000, and the Mw was 61,000. And Mw/Mn was 3.81, the saturated water absorption at 23 ° C was 0.18%, and the logarithmic viscosity in chloroform at 30 ° C was 0.52 dl / g.

[Synthesis Example 3] (Production of cyclic olefin resin C)

In the synthesis example 1, a hydrogenated polymer was obtained in the same manner as in Synthesis Example 1 except that the amount of DNM was changed to 250 parts and the amount of 1-hexene added was 18 parts (hereinafter referred to as "resin C". ).

The hydrogenation rate measured by ¹ H-NMR of the resin C obtained in this manner was 99.9%, and the Tg measured by the DSC method was 165 ° C, and the Mn in terms of polystyrene measured by the GPC method was 32,000, and the Mw was 137,000. And Mw/Mn was 4.29, the saturated water absorption at 23 ° C was 0.3%, and the logarithmic viscosity in chloroform at 30 ° C was 0.78 dl / g.

[Preparation example] (modulation of water-based adhesive)

250 parts of distilled water was fed into the reaction vessel, and 90 parts of butyl acrylate, 8 parts of 2-hydroxyethyl methacrylate, 2 parts of divinylbenzene, and 0.1 parts of potassium oleate were added to the reaction vessel, and then iron was borrowed. The stirring blade made of fluorocarbon (registered trademark) was stirred and dispersed.

After the nitrogen substitution in the reaction vessel, the system was heated to 50 ° C, and 0.2 parts of potassium persulfate was added to initiate polymerization. After 2 hours, 0.1 part of potassium persulfate was further added, and the temperature was raised to 80 ° C, and the polymerization reaction was continued for 1 hour to obtain a polymer dispersion.

Then, the polymer dispersion was concentrated to a solid concentration of 70% using a distiller, and a water-based adhesive (adhesive having a polarity) composed of an aqueous dispersion of an acrylate-based polymer was obtained.

The acrylate-based polymer constituting the water-based adhesive obtained by the above method has a number average molecular weight (Mn) and a weight average molecular weight (Mw) in terms of polystyrene by a GPC method (solvent: tetrahydrofuran), and Mn is 69,000. The Mw was 135,000 and the logarithmic viscosity measured in chloroform at 30 ° C was 1.2 dl / g.

[Manufacturing Example 1] (Production of Raw Material Film A)

The resin A obtained in Synthesis Example 1 was dissolved in toluene to have a concentration of 30% (solution viscosity at room temperature was 30,000 mPa ‧ s), and pentaerythritol 4 [3-(3,5-di) was added to 100 parts by weight of the resin. Tributyl-4-hydroxyphenyl)propionate] 0.1 parts by weight as an antioxidant, a metal fiber sintered filter having a pore size of 5 μm manufactured by Japan Ball, and a flow rate of 0.4 MPa or less Filtered on one side.

The resin solution produced by the above-mentioned method is a biaxial extruder (TEM-48, manufactured by Toshiba Machine Co., Ltd.), and the toluene is degassed by three stages of exhaust gas, and is pumped downward by a gear pump to make it flow downward. The resin flowing out of the strand is cooled in a cooling water tank, sent to a strand cutter, and cut into rice grains to obtain a granulated resin.

The granulated resin was dried at 100 ° C for 4 hours in a nitrogen atmosphere, and then sent to a uniaxial extruder (90 mm Φ), and melted at 260 ° C while being metered by gear pumping, using a nominal mesh of 10 μm. A metal fiber sintered filter made by Nippon Seisen Co., Ltd. was subjected to melt filtration, and a cooling frame type die (1700 mm wide) was used, and a gap of 0.5 mm at the exit of the cooling frame die was taken out at 260 ° C to form a film. The length of the strand of the die used at this time (the length of the parallel portion of the die exit) was 20 mm. The distance from the die exit to the roll contact point is 65 mm, so that the extruded film is transferred between the mirror roll having a surface roughness of 0.1 S and 250 mmφ and the metal transfer belt of 0.3 mm thick to transfer the surface of the film. To the shiny side. A metal conveyor belt (width: 1650 mm) is a rubber-coated roller (the diameter of the roller to be held is 150 mmφ), and is held by a cooling roller (roller diameter: 150 mm), and a commercially available sleeve type transfer roller (manufactured by Chiba Machinery Co., Ltd.) is used. , transfer. The roller interval at the time of transfer was 0.35 mm, and the transfer pressure was 0.35 MPa.

At this time, the peripheral speed of the outer circumference of the mirror roll was 10 m/min. The temperature of the mirror roll at this time was set to 125 ° C using an oil temperature adjuster, and the temperature of the rubber coating roll was set to 115 ° C.

A cooling roll of 250 mmφ was placed on the flow side under the mirror roll, and the film peeled off from the mirror roll was cooled by pressing the chill roll set at 115 ° C for 2.1 seconds. Then, the film was peeled off at a peeling force of 0.4 MPa ‧ cm, and the mask film was bonded to one side, and wound up by a winder to obtain a resin film having a thickness of 130 μm (hereinafter referred to as "raw material film A"). The obtained film had a residual solvent amount of 0.1%, a total light transmittance of 93%, and a glass transition temperature (Tg) of 130 °C.

[Manufacturing Example 2] (Manufacture of Raw Material Film B)

In the production example 1, except that the resin B obtained in the synthesis example 2 was used instead of the resin A, a resin film having a thickness of 130 μm (hereinafter referred to as "raw material film B") was obtained in the same manner as in Production Example 1. The obtained film had a residual solvent amount of 0.1%, a total light transmittance of 93%, and a glass transition temperature (Tg) of 131 °C.

[Manufacturing Example 3] (Manufacture of Raw Material Film C)

The resin C obtained in Synthesis Example 3 was dissolved in toluene to have a concentration of 30% (solution viscosity at room temperature was 30,000 mPa ‧ s), and pentaerythritol 4 (3-(3, 5-) was added to 100 parts by weight of the polymer. 0.1 parts by weight of di-tert-butyl-4-hydroxyphenyl)propionate] As an antioxidant, a metal fiber sintered filter having a pore size of 5 μm manufactured by Japan Ball was used, and the solution was controlled while the pressure difference was within 0.4 MPa. The flow rate was filtered while using a INVEX Labocoater manufactured by Inoue Metal Industries Co., Ltd., which is installed in a clean room of class 1000, and the obtained polymer solution was treated with an acrylic hydrophilic (adhesive) surface-treated PET having a thickness of 100 μm. The film (manufactured by Toray Co., Ltd., Luminer U94) was applied so as to have a film thickness of 130 μm after drying, and once dried at 50 ° C, and then peeled off from the PET film and secondarily dried at 90 ° C to obtain a resin. The film (hereinafter referred to as "film C") had a residual solvent amount of 0.1%, a total light transmittance of 93%, and a glass transition temperature (Tg) of 165 °C.

[Manufacturing Example 4] [Manufacture of Protective Film]

Using a biaxial extruder, 0.3 parts of (pentaerythritol tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)propionate: melting point 115 ° C) with respect to 100 parts of the resin A, (2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl) as a benzotriazole compound Phenol]: Melting point 199 ° C) 1.5 parts of the blending ratio was melt-kneaded at 270 ° C, and then extruded out of the strands, and after water cooling, the pellets were obtained by Feeder-Ruder. The obtained pellets were dehumidified and dried by circulating at 100 ° C for 3 hours under nitrogen, and then sent to a hopper, and melted at a resin temperature of 270 ° C using a uniaxial extruder having a screw diameter of 75 mm Φ.

The molten resin was pumped by a biaxial discharge type gear at a rate of 30 kg/hr, and introduced into a 700 mm wide cooling rack type die through a polymer filter (mesh 5 μm) heated to 280 °C. The pressure difference between the inlet and the outlet of the filter is 3 MPa. Further, the heater of the die was set at 250 ° C using an aluminum casting heater, and a lip heater was attached to the front lip to control the lip temperature of the die to 250 ± 0.4 °C.

The lip opening degree was set to 0.5 mm in the width direction, and the fine adjustment system measured thickness unevenness on a line thickness gauge disposed on the downstream side of the melt extrusion. The resin extruded from the die is dropped toward the vertical tangential direction of a 250 mm Φ casting roll (surface roughness: 0.1 μ), and is pressed against the casting roll shaft, and the two cooling rolls are horizontally pressed and then peeled off. The tension was controlled by 4 kgf to obtain a protective film α having a thickness of 80 μm.

[Manufacturing Example 5] (Manufacture of polarizer)

A 120 μm roll-shaped polyvinyl alcohol (hereinafter, also referred to as "PVA") film was continuously dyed at a stretching ratio of 30 ° C aqueous solution having an iodine concentration of 0.03% by weight and a potassium iodide concentration of 0.5% by weight. After uniaxial stretching (front extension) in the longitudinal direction, a 55° C. cross-linking bath having a boric acid concentration of 5% by weight and an aqueous solution having a potassium iodide concentration of 8% by weight is further carried out in a long direction at a stretching ratio of 2 times. After the shaft was extended (post-stretched), it was dried and wound up to obtain a 27 μm roll-shaped polarizer.

[Example 1]

The raw material film A obtained in Production Example 1 was stretched at a stretching speed of 5 m/min in a groove at a temperature of 136 ° C in an extension furnace at a stretching ratio of 1.4 times, and the uniaxial stretching in the film length direction in the film width direction was not fixed. In a groove having a temperature of 150 ° C in the furnace of the stretching machine, the stretching speed was 5.0 m/min and the stretching ratio was 1.7 times, and the tensile stretching machine was laterally stretched to obtain a roll-shaped retardation film A having a thickness of 69 μm. The in-plane phase difference R0 of the obtained retardation film A was 40.1 nm, and the NZ coefficient was 2.9.

The phase difference film A obtained was subjected to the state of the one-side aligned roll-shaped film of the polarizer obtained in Production Example 5 (the direction in which the absorption axis of the polarizer was extended and the direction of the maximum refractive index of the retardation film A were orthogonal to each other) And using the water-based adhesive obtained by the preparation example, the two were continuously adhered, and the surface of the polarizer was used for the water-based adhesive obtained by the preparation example, and it adhered to the manufacturing example 4. The film α was protected to obtain a polarizing plate A-1. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 42.1% and 99.9%, respectively. Further, after the wet heat test and the dry heat test were performed on the obtained polarizing plate A-1, both were ◎. The results are shown in Table 1.

The polarizer of the viewer side and the back side of the TN mode liquid crystal display element of the LCD TV (model model: LS 20 BRDBBV/XSJ) manufactured by Samsung Electronics Co., Ltd. is peeled off, and the polarizing plate A-1 is doubled at the place where it is peeled off. The surface is adhered to the same manner as the transmission axis of the polarizing plate which is adhered to the original surface, and the film surface of the polarizing plate is adhered to the liquid crystal cell side.

After confirming the omnidirectional viewing angle (region having a contrast ratio of 10 or more) of the obtained TN mode liquid crystal display element, it was confirmed that the upper and lower sides were about 160 degrees and 160 degrees. Further, after confirming the presence or absence of a bright spot at the time of black display, the panel has one overall. The results are shown in Table 1.

[Embodiment 2]

The raw material film A obtained in Production Example 1 was stretched at a stretching speed of 5 m/min and a stretching ratio of 3.0 times in a bath at a temperature of 145 ° C in an extension furnace to obtain a roll-like phase of a thickness of 43 μm. Poor film B. The in-plane phase difference R0 of the obtained retardation film B was 90.2 nm, and the NZ coefficient was 1.3.

In the first embodiment, the polarizing plate B-1 was obtained in the same manner as in the first embodiment except that the retardation film B was used instead of the retardation film A. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 42.0% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and both were ◎.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was 160 degrees above and below 123 degrees, and the presence or absence of the bright spot was confirmed. The results are shown together in Table 1.

[Example 3]

The raw material film B obtained in Production Example 2 was stretched at a stretching speed of 5 m/min in a groove at a temperature of 138 ° C in an extension furnace at a stretching ratio of 1.4 times, and the uniaxial stretching in the film length direction in the film width direction was not fixed. In a groove having a temperature of 152 ° C in the furnace of the stretching machine, the stretching speed was 5.0 m/min and the stretching ratio was 1.7 times, and the tensile stretching machine was laterally stretched to obtain a roll-shaped retardation film C having a thickness of 72 μm. The in-plane phase difference R0 of the obtained retardation film C was 40.0 nm, and the NZ coefficient was 2.9.

In the first embodiment, the polarizing plate C-1 was obtained in the same manner as in the first embodiment except that the retardation film C was used instead of the retardation film A. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 42.0% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and both were ◎.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was about 158 degrees above and below 123 degrees, and the presence or absence of the bright spot was confirmed, and the panel was completely zero. The results are shown together in Table 1.

[Example 4]

The raw material film C obtained in Production Example 3 was stretched at a stretching speed of 5 m/min in a groove at a temperature of 169 ° C in an extension furnace at a stretching ratio of 1.4 times, and the uniaxial stretching in the film length direction in the film width direction was not fixed. In a groove having a temperature of 183 ° C in the furnace of the stretching machine, the stretching speed was 5 m/min and the stretching ratio was 1.7 times, and the tensile stretching machine was horizontally stretched to obtain a roll-shaped retardation film D having a thickness of 73 μm. The in-plane phase difference R0 of the obtained retardation film D was 40.4 nm, and the NZ coefficient was 2.9.

In the first embodiment, the polarizing plate D-1 was obtained in the same manner as in Example 1 except that the retardation film D was used instead of the retardation film A. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 42.1% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and both were ◎.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was 153 degrees from the upper and lower sides of the angle of 122 degrees. After confirming the presence or absence of the bright spot, the panel was comprehensive. The results are shown together in Table 1.

[Example 5]

In the first embodiment, a polarizing plate A-2 was obtained in the same manner as in Example 1 except that a film made of triethylenesulfonyl cellulose (hereinafter also referred to as "TAC") was used to change to the protective film α. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 41.6% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and were ◎ and ○, respectively.

In the same manner as in the first embodiment, after the TN mode liquid crystal display device was obtained and evaluated, the viewing angle was 119 degrees up and down at 119 degrees, and the presence or absence of the bright spot was confirmed. The results are shown together in Table 1.

[Embodiment 6]

In the second embodiment, a polarizing plate B-2 was obtained in the same manner as in Example 2 except that the film made of TAC was changed to the protective film α. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 41.7% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and were ◎ and ○, respectively.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was 129 degrees from about 118 degrees to the upper and lower sides, and the presence or absence of the bright spot was confirmed. The results are shown together in Table 1.

[Embodiment 7]

In the third embodiment, a polarizing plate C-2 was obtained in the same manner as in Example 3 except that the film made of TAC was changed to the protective film α. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 41.5% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and were ◎ and ○, respectively.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was 155 degrees up and down at about 116 degrees, and the presence or absence of the bright spot was confirmed, and the panel was completely zero. The results are shown together in Table 1.

[Embodiment 8]

In Example 4, a polarizing plate D-2 was obtained in the same manner as in Example 4 except that the film formed by TAC was changed to the protective film α. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 41.4% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and were ◎ and ○, respectively.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was about 154 degrees above and below 114 degrees, and after confirming the presence or absence of the bright spot, the panel was comprehensively three. The results are shown together in Table 1.

[Embodiment 9]

A cellulose-based resin unstretched film having a ratio of substitution ratio of ethyl thiol group to degree of substitution of propyl fluorenyl group of 70/30, in an extruder at a temperature of 138 ° C in the furnace, at an extension speed of 5 m / min, and a stretching ratio of 1.6 times After the uniaxial stretching in the longitudinal direction of the film in the width direction of the film is not fixed, the stretching speed is 5 m/min and the stretching ratio is 1.9 times in the groove of the extruder temperature of 152 ° C, and the transverse stretching of the tensile machine is performed to obtain a thickness of 52 μm. Roll-shaped retardation film E. The in-plane phase difference R0 of the obtained retardation film E was 40.5 nm, and the NZ coefficient was 2.9.

In the first embodiment, the polarizing plate E-1 was obtained in the same manner as in the first embodiment except that the retardation film E was changed to the retardation film A. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 41.3% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and were ◎ and ○, respectively.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was about 152 degrees from 113 degrees to about 135 degrees. After confirming the presence or absence of the bright spot, the panel was comprehensively four. The results are shown together in Table 1.

[Comparative Example 1]

The raw material film A obtained in Production Example 1 was stretched at a stretching speed of 5 m/min and a stretching ratio of 2.3 times in a groove of an elongation furnace at a temperature of 135 ° C to obtain a roll-like phase of 65 μm thick. Poor film F. The in-plane phase difference R0 of the obtained retardation film F was 180.4 nm, and the NZ coefficient was 1.4.

In the first embodiment, the polarizing plate F-1 was obtained in the same manner as in the first embodiment except that the retardation film F was changed to the retardation film A. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 42.1% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 1, and were respectively ◎.

In the same manner as in the first embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was 159 degrees up and down by about 40 degrees, and the vertical direction was The perspective is very narrow. After confirming the presence or absence of a bright spot, the panel is fully integrated. The results are shown together in Table 1.

[Comparative Example 2]

The raw material film A obtained in Production Example 1 was stretched at a stretching speed of 5 m/min in a groove at a temperature of 133 ° C in an extension furnace at a stretching ratio of 1.6 times, and the uniaxial stretching in the film length direction in the film width direction was not fixed. In a groove having a temperature of 146 ° C in the furnace of the stretching machine, the stretching speed was 5.0 m/min and the stretching ratio was 1.9 times, and the tensile stretching machine was horizontally stretched to obtain a roll-shaped retardation film G having a thickness of 56 μm. The in-plane phase difference R0 of the obtained retardation film G was 40.1 nm, and the NZ coefficient was 5.3.

In the same manner as in Example 5 except that the retardation film G was changed to the retardation film A, the polarizing plate G-2 was obtained. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 41.9% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 5, and were ◎ and ○, respectively.

In the same manner as in the fifth embodiment, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was about 143 degrees from about 43 degrees to the top and bottom, and the viewing angle in the vertical direction was very narrow. After confirming the presence or absence of a bright spot, the panel is comprehensively three. The results are shown together in Table 1.

[Comparative Example 3]

An alignment film is formed on a triacetonitrile-based cellulose film having a thickness of 80 μm, and the alignment film is modified by a vinyl-based repeating unit having a linking group in a side chain. The composition of the PVA is formed by applying a composition of a discotic liquid crystal compound having a polymerizable group bond and a photopolymerization initiator to the alignment film, and then irradiating the ultraviolet ray to obtain a retardation film H. The in-plane phase difference R0 of the obtained retardation film H was 40.5 nm, and the NZ coefficient was 456. In the same manner as in Example 5 except that the retardation film H was changed to the retardation film A, the polarizing plate H-2 was obtained. The monomer transmittance and polarization degree of the polarizing plate obtained by the institute were 40.9% and 99.9%, respectively. Further, the damp heat test and the dry heat test were carried out in the same manner as in Example 5, and were ◎ and ×, respectively.

In the same manner as in Example 5, after the TN mode liquid crystal display element was obtained and evaluated, the viewing angle was about 146 degrees above and below 120 degrees. After confirming the presence or absence of the overall highlight of the panel, the panel has a total of 15 panels. The results are shown together in Table 1.

Claims (6)

A TN (Twist Nematic) mode liquid crystal display device in which a retardation film made of a thermoplastic resin and two polarizing plates of a polarizer are sandwiched between liquid crystal cells and disposed on the viewer side and the back side of the liquid crystal display element. And the retardation films constituting the respective polarizing plates satisfy the following formulas (i), (ii) and (iii), and the respective polarizing plates are such that the maximum refractive index direction in the film plane of the retardation film is The absorption axis of the polarizer is perpendicular and the two are bonded together; (i) 20 nm ≦ R0 ≦ 150 nm (ii) 1.1 ≦ NZ ≦ 4.3 (iii) 200 nm ≦ R0f × NZf + R0r × NZr ≦ 260 nm here, R0 represents the phase difference in the plane of the film, NZ represents the NZ coefficient, and the maximum refractive index in the plane of the film at a wavelength of 550 nm is nx, and the refractive index in the direction perpendicular to nx in the plane of the film is ny, the film The refractive index in the thickness direction is nz, and the thickness is d (nm), the value obtained by the formula R0 = (nx - ny) × d and the formula NZ = (nx - nz) / (nx - ny); R0f and NZf represents R0 and NZ of the optical film on the observer side of the liquid crystal display element, and R0r and NZr respectively represent R0 and NZ of the optical film on the back side of the liquid crystal display element. For example, in the TN mode liquid crystal display device of claim 1, wherein any one of the phase difference films satisfies the following formulas (iv) and (v) (iv) 70 nm ≦ R0 ≦ 150 nm (v) 1.1 ≦ NZ ≦ 1.5. The TN mode liquid crystal display device of claim 2, wherein the thermoplastic resin constituting the retardation film is a cyclic olefin resin having a repeating unit represented by the following formula (I); In the formula (I), m is an integer of 1 or more, p is an integer of 0 or more, D is a group represented by -CH=CH- or -CH ₂ CH ₂ -, and R ¹ to R ⁴ are each independently And a substituent selected from the group consisting of a hydrogen atom; a halogen atom; an oxygen atom, a sulfur atom, a nitrogen atom or a ruthenium atom; a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; and a group of polar groups; R ¹ and R ² may be integrated to form a divalent hydrocarbon group, and R ³ and R ⁴ may be integrated to form a divalent hydrocarbon group; and R ¹ and R ² may be bonded to each other to form a carbocyclic or heterocyclic ring. R ³ and R ⁴ may be bonded to each other to form a carbocyclic or heterocyclic ring, and the carbocyclic or heterocyclic ring may be monocyclic or polycyclic. The TN mode liquid crystal display device according to any one of claims 1 to 3, wherein the polarizing plate further has a protective film. The TN mode liquid crystal display element according to any one of claims 1 to 3, which is obtained by a manufacturing method having the following steps; a step of stretching a raw material film made of a thermoplastic resin to form a retardation film satisfying the above formulas (i) and (ii); and disposing the retardation film and the polarizer to form a polarizing plate; The step of overlapping the polarizing plate with the liquid crystal cell. The TN mode liquid crystal display device according to any one of claims 1 to 3, wherein the retardation film constituting the polarizing plate is obtained by extending a material film composed of a thermoplastic resin.