JP2008096925A - Olefin series laminated polarizing plate, liquid crystal display element and display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate wherein the stability of polarization degree in an obtained polarizing plate can be raised. <P>SOLUTION: On one surface of a polarizer (a), a film (b) containing a polymer having a structural unit introduced from at least one sort chosen from 4-methyl-1-pentene, 3-methyl-1-pentene and 3-methyl-1-butene is directly or indirectly laminated. On another surface of the polarizer (a), a film (c) containing a polymer having a structural unit introduced from an annular olefin is directly or indirectly laminated to form a laminated polarizing plate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, a film containing a polymer having a structural unit derived from poly-4-methyl-1-pentene or the like on one surface of a polarizer has a polymer having a structural unit derived from a cyclic olefin on the other surface. It is related with the laminated polarizing plate by which the film to include is each laminated | stacked directly or indirectly. Moreover, this invention relates to a liquid crystal display element provided with this laminated polarizing plate. Moreover, this invention relates to a display apparatus provided with the said laminated polarizing plate and / or a liquid crystal display element.

  With the recent development of various display devices such as liquid crystal display elements, the importance of various optical elements such as retardation plates and polarizing plates is increasing. A liquid crystal display element will be described as an example. The liquid crystal display element modulates the polarization state of light with a liquid crystal cell and filters the light with a polarizing film to control display brightness and display an image. Here, the light that has passed through the liquid crystal cell includes a circularly polarized component that cannot be filtered by the polarizing film, and may cause a deterioration in display contrast. Therefore, before the light that has passed through the liquid crystal cell is incident on the polarizing film, it is widely performed to correct the circularly polarized light by passing through a retardation plate and improve the contrast of the liquid crystal display element.

  Patent Document 1 discloses a polarizing film in which a protective film is laminated on both sides of a polarizing film, and at least one of the protective films has a function of a retardation film at the same time. As the protective film, it is described that a cellulose-based film such as triacetyl cellulose (TAC) is preferably used.

  Patent Document 2 discloses a polarizing plate protective film made of poly-4-methyl-1-pentene. It is disclosed that a polarizing plate protective film made of poly-4-methyl-1-pentene can reduce birefringence.

Patent Document 3 discloses a polarizing film in which a cyclic olefin resin film is laminated on one surface of a polarizing film and a protective film having a water vapor transmission rate within a certain range is laminated on the other surface.
JP-A-8-43812 JP 2000-275433 A JP 2002-221619 A

  By the way, since polyvinyl alcohol containing water is usually used as the polarizing film, if the removal of this water is insufficient in the manufacturing process of the polarizing plate, the water content in the polarizing film of the polarizing plate to be manufactured becomes large. Insufficient adhesive strength between the film and the polarizing plate protective film and a decrease in polarization degree are likely to occur.

  In particular, the polarizing plate provided with the polarizing plate protective film described in Patent Document 1 still had to be improved from the viewpoint of the stability of the polarization degree of the obtained polarizing plate. In addition, the polarizing plate protective film described in Patent Document 3 uses a material having high water vapor permeability. However, it is mentioned that the retardation of a film using this material is adjusted to act as a retardation plate. It is not done. In addition, materials listed as materials having high water vapor permeability include those having high water absorption, and there was still a point to be improved from the viewpoint of stability of polarization degree of the obtained polarizing film. Furthermore, since the polarizing plate described in Patent Document 2 has a film made of poly-4-methyl-1-pentene having high water vapor permeability on both surfaces, the polarizing film is formed by moisture, a solvent, or the like from the outside. There was a risk of being affected.

  Therefore, the present inventors form a polarizing plate protective film using a material having low water absorption and high water vapor permeability and a polarizing plate protective film using a material having high gas barrier properties, and laminating them with a polarizer. As a result, the inventors have found that the stability of the polarization degree of the obtained polarizing plate can be enhanced, and have reached the present invention.

Therefore, the present invention provides
(1) A structural unit derived from at least one selected from 4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-butene on one surface of the polarizer (a) A film (c) containing a polymer having a structural unit derived from a cyclic olefin on the other surface of the polarizer (a), wherein the film (b) containing a polymer having a polymer is directly or indirectly laminated ) Are laminated directly or indirectly.
(2) The laminated polarizing plate according to item (1), wherein the in-plane retardation R (590) of the film (c) at a wavelength of 590 nm satisfies the relationship of the following formula (1).
R (590) ≧ 10 (nm) (1)
(3) The laminated polarizing plate according to (1) or (2), wherein the polarizer (a) contains iodine and / or a dichroic dye and a polyvinyl alcohol resin.
(4) A liquid crystal display device comprising the laminated polarizing plate according to any one of items (1) to (3) and a liquid crystal cell.
(5) The liquid crystal display element according to item (4), wherein the film (c) is disposed on the liquid crystal cell side with respect to the polarizer (a).
(6) A display device comprising the laminated polarizing plate according to any one of items (1) to (3) and / or the liquid crystal display element according to (4) or (5).
I will provide a.

  ADVANTAGE OF THE INVENTION According to this invention, the polarizing plate which can improve the stability of the polarization degree of the polarizing plate obtained can be provided.

Hereinafter, embodiments of the present invention will be described.
The laminated polarizing plate of this embodiment has at least one selected from 4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-butene on one surface of the polarizer (a). The polymer (b) containing a polymer containing a structural unit derived from a seed is directly or indirectly laminated, and the polymer having a structural unit derived from a cyclic olefin on the other surface of the polarizer (a) It is a laminated polarizing plate by which the film (c) containing is laminated | stacked directly or indirectly.

(1) Polarizer (a)
The polarizer (a) used in the present embodiment is not particularly limited as long as it has a function as a polarizer.
For example, a polarizing film containing iodine and / or a dichroic dye and a polyvinyl alcohol resin, such as a polyvinyl alcohol (PVA) / iodine polarizing film, a dye-based polarizing film in which a dichroic dye is adsorbed and oriented on a PVA film In addition, the surface of a PVA film comprising a polyene polarizing film in which a polyene is formed by inducing a dehydration reaction from a PVA film or by a dehydrochlorination reaction of a polyvinyl chloride film, or a modified PVA containing a cationic group in the molecule And / or a polarizer having a polarizing film containing a dichroic dye therein.

(2) Film (b)
In this embodiment, the film (b) used as the protective film for the polarizer (a) is selected from 4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-butene. It contains a polymer having a structural unit derived from at least one kind.

  Such a film (b) uses at least one olefin selected from 4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-butene as a (co) polymerization component. The specific (co) polymer (α) obtained in this manner is contained. Here, “containing” means that when the entire film (b) is composed of the (co) polymer (α), a part of the film (b) is composed of the (co) polymer (α). If it is, it is intended to include both. Therefore, the film (b) may or may not contain components other than the (co) polymer (α). From the viewpoint of effectively realizing the effect of the present invention, the content of the (co) polymer (α) in the film (b) is 20 to 100% by weight, more preferably 50 to 100% by weight. desirable.

((Co) polymer (α))
The specific (co) polymer (α) used in the film (b) is at least one selected from 4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-butene. The olefin was obtained as a (co) polymerization component. The specific olefinic (co) polymer (α) is a homopolymer of 3-methyl-1-butene, 3-methyl-1-pentene or 4-methyl-1-pentene, or a copolymer of these. , Copolymers with other copolymerizable monomers such as styrene, acrylonitrile, vinyl chloride, vinyl acetate, acrylic acid esters, methacrylic acid esters, etc., or the above-mentioned ones or other thermoplastic resins or synthetics Examples thereof include a blend with rubber, a block copolymer, and a graft copolymer. Among the structural units of the (co) polymer (α), the structural units derived from 4-methyl-1-pentene, 3-methyl-1-pentene, or 3-methyl-1-butene are generally 20 to It is 100 mol%, preferably 50 to 100 mol%, more preferably 80 to 100 mol%. When the content of the structural unit derived from 4-methyl-1-pentene, 3-methyl-1-pentene, or 3-methyl-1-butene is within the above range, various properties such as transparency and heat resistance can be obtained. This is preferable because a resin having an excellent balance can be obtained.

  Among the (co) polymers (α), the 4-methyl-1-pentene (co) polymer is preferable because it is excellent in transparency, releasability and the like and is suitable for use in combination with an optical element. In addition, 3-methyl-1-pentene (co) polymer and 3-methyl-1-butene (co) polymer are excellent in heat resistance, from the viewpoint of the degree of freedom of process, the degree of freedom of use conditions, and the like. preferable.

(4-Methyl-1-pentene (co) polymer)
The 4-methyl-1-pentene (co) polymer preferably used as the (co) polymer (α) in the present invention is specifically a homopolymer of 4-methyl-1-pentene or 4-methyl- Copolymerization of 1-pentene with ethylene or other α-olefins having 3 to 20 carbon atoms such as propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene, 1-octadecene, etc. It is a coalescence. The 4-methyl-1-pentene (co) polymer preferably used in the present invention usually contains a structural unit derived from 4-methyl-1-pentene in an amount of 85 mol% or more, preferably 90 mol% or more. To do. There are no particular limitations on the constituents other than those derived from 4-methyl-1-pentene, which constitute the 4-methyl-1-pentene (co) polymer, and various monomers copolymerizable with 4-methyl-1-pentene. Can be used as appropriate, but ethylene or an α-olefin having 3 to 20 carbon atoms can be preferably used from the viewpoints of availability, copolymerization characteristics, and the like. Among these, α-olefins having 6 to 20 carbon atoms are preferable, and 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene are particularly preferable.

  The melt flow rate (MFR) of 4-methyl-1-pentene (co) polymer preferably used in the present invention, measured under the conditions of a load of 5 kg and a temperature of 260 ° C. according to ASTM D1238, is variously determined depending on applications. However, it is usually in the range of 1 to 50 g / 10 minutes, preferably 2 to 40 g / 10 minutes, and more preferably 5 to 30 g / 10 minutes. When the melt flow rate of the 4-methyl-1-pentene (co) polymer is in the above range, the film moldability and the appearance of the resulting film are good. The melting point is preferably in the range of 100 to 240 ° C, preferably 150 to 240 ° C.

  Moreover, there is no restriction | limiting in particular in the manufacturing method of such a 4-methyl-1- pentene (co) polymer, It can manufacture also by a conventionally well-known method, for example, it describes in Unexamined-Japanese-Patent No. 59-206418. As shown, it can be obtained by polymerizing 4-methyl-1-pentene and the above ethylene or α-olefin in the presence of a catalyst.

(3-methyl-1-pentene (co) polymer)
The preferred comonomer type, comonomer content, MFR, melting point, etc. of the 3-methyl-1-pentene (co) polymer preferably used as the (co) polymer (α) in the present invention are the above 4-methyl-1- The same as in the case of the pentene (co) polymer. There is no particular limitation on the method for producing the 3-methyl-1-pentene (co) polymer preferably used in the present invention, and it can be suitably produced by a conventionally known method. For example, JP-A-06-145248 It can be produced by the method described in the publication.

(3-methyl-1-butene (co) polymer)
The preferred comonomer type, comonomer content, MFR, melting point and the like of the 3-methyl-1-butene (co) polymer preferably used as the (co) polymer (α) in the present invention are the above 4-methyl-1- The same as in the case of the pentene (co) polymer. There is no particular limitation on the method for producing the 3-methyl-1-butene (co) polymer preferably used in the present invention, and it can be suitably produced by a conventionally known method. For example, Japanese Patent Application Laid-Open No. 06-145248. It can be produced by the method described in the publication.

(Components constituting the film (b) in addition to the (co) polymer (α))
The film (b) used in the present invention may contain various components other than the above (co) polymer (α). The components other than the (co) polymer (α) may be various resins or various rubbers other than the (co) polymer (α). As various resins, resins having excellent transparency are particularly preferable. For example, various polyolefins such as cyclic olefin (co) polymers, polycarbonates, polystyrenes, cellulose acetate resins, fluororesins, polyesters, acrylic resins, and the like are used. I can do it. As various rubbers, olefin rubber, styrene rubber, and the like can be used. The film (b) used in the present invention includes an antistatic agent, an antioxidant, a heat resistance stabilizer, a release agent, a weather resistance stabilizer, a rust inhibitor, a slip agent, a nucleating agent, a pigment, a dye, and an inorganic filler. Various compounding agents usually used by adding to polyolefin such as (silica and the like) and other special compounding agents can be added within a range not impairing the object of the present invention.

(Method for producing film (b))
There is no restriction | limiting in particular in the manufacturing method of the film (b) used in this invention, Although it can produce suitably also by a conventionally well-known method, For example, (co) polymer ((alpha)) and other components are, Method of mixing with V-blender, ribbon blender, Henschel mixer, tumbler blender, or mixing with the blender, then melt kneading with single screw extruder, double screw extruder, kneader, Banbury mixer etc. to granulate or grind Then, the film can be formed by a known method such as press molding, extrusion molding, inflation molding, or a solution casting method. In order to produce efficiently, a solution casting method, an inflation molding method, an extrusion molding method, and the like are preferable.

  In addition, by stretching the obtained film, it is possible to optically adjust physical properties such as birefringence, its angular dependence, temperature dependence, etc. to desired values, and to provide mechanical strength. It can also be. The draw ratio may be appropriately selected depending on the desired optical properties and the like, but is usually 1.5 to 10 times, preferably 2 to 5 times.

  The thickness of the film (b) may be appropriately set depending on the purpose of use, particularly the birefringence of the polarizer (a) and its wavelength dependency, and is not particularly limited, but is usually 10 to 200 μm, preferably 20 to 100 μm. is there. If it is such a range, it is excellent in productivity of a film, and since a sufficient strength is also obtained without producing a pinhole etc. at the time of film forming, it is preferable. However, the optical design is usually given priority as described above.

(3) Film (c)
In this embodiment, the film (c) used as a protective film for the polarizer (a) contains a polymer (cyclic olefin (co) polymer) having a structural unit derived from a cyclic olefin.

  That is, the film (c) contains an alicyclic structure-containing polymer. Here, “containing” means that the entire film is composed of the alicyclic structure-containing polymer, and a part of the film is composed of the alicyclic structure-containing polymer. If it is, it is intended to include both. The content of the alicyclic structure-containing polymer is not particularly limited, but is usually 50 to 100% by weight, preferably 60 to 100% by weight, and more preferably 70 to 100% from the viewpoint of optical homogeneity. % By weight. Moreover, although there is no restriction | limiting in particular in components other than the said resin, For example, an olefin-type elastomer and a styrene-type elastomer can be added from a viewpoint of an impact resistance improvement. Further, as will be described later, various other additives may be used.

  The alicyclic structure-containing polymer contains an alicyclic structure in the repeating unit of the polymer, and may have an alicyclic structure in either the main chain or the side chain. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15, and excellent heat resistance and flexibility. Film is obtained. The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use, but is usually 20% by weight or more, preferably 40% by weight or more, more preferably 60% by weight or more. If the ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is sufficient, heat resistance is excellent, which is preferable. In addition, the remainder other than the repeating unit which has an alicyclic structure in an alicyclic structure containing polymer is not specifically limited, According to the intended purpose, it selects suitably.

  Specific examples of the polymer resin containing an alicyclic structure include (1) norbornene polymer, (2) monocyclic olefin polymer, (3) cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrogenated products thereof. Among these, from the viewpoints of dimensional stability, oxygen permeability, moisture permeability, heat resistance, mechanical strength, and the like, norbornene polymers, vinyl alicyclic hydrocarbon polymers, and hydrogenated products thereof are preferable.

(1) Norbornene-based polymer The norbornene-based polymer includes a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization, and hydrogen thereof. Examples include additives, addition polymers of norbornene monomers, addition copolymers of norbornene monomers and other monomers copolymerizable therewith.

  In the hydrogenated product of a ring-opening polymer of a norbornene-based monomer and the hydrogenated product of a ring-opening copolymer of a norbornene-based monomer and another monomer capable of undergoing ring-opening copolymerization, the hydrogenation rate is 99. % Or more, it is excellent in transparency (especially low initial yellowing degree), stability (especially yellowing is difficult to occur in the long term), etc., and can often suppress the generation of gel, preferable.

  Among these, addition copolymers of norbornene monomers and other monomers copolymerizable therewith are most preferable because desired retardation can be easily obtained.

As the norbornene-based monomer, bicyclo [2.2.1] -hept-2-ene (common name: norbornene), 5-methyl-bicyclo [2.2.1] -hept-2-ene, 5,5- Dimethyl-bicyclo [2.2.1] -hept-2-ene, 5-ethyl-bicyclo [2.2.1] -hept-2-ene, 5-butyl-bicyclo [2.2.1] -hept 2-ene, 5-hexyl-bicyclo [2.2.1] -hept-2-ene, 5-octyl-bicyclo [2.2.1] -hept-2-ene, 5-octadecyl-bicyclo [2] 2.1] -hept-2-ene, 5-ethylidene-bicyclo [2.2.1] -hept-2-ene, 5-methylidene-bicyclo [2.2.1] -hept-2-ene, 5-vinyl-bicyclo [2.2.1] -hept-2-ene, 5- Lopenyl-bicyclo [2.2.1] -hept-2-ene, 5-methoxy-carbonyl-bicyclo [2.2.1] -hept-2-ene, 5-cyano-bicyclo [2.2.1] -Hept-2-ene, 5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] -hept-2-ene, 5-methoxycarbonyl-bicyclo [2.2.1] -hept-2-ene 5-ethoxycarbonyl-bicyclo [2.2.1] -hept-2-ene, 5-methyl-5-ethoxycarbonyl-bicyclo [2.2.1] -hept-2-ene, bicyclo [2.2 .1] -Hept-5-enyl-2-methylpropionate, bicyclo [2.2.1] -hept-5-enyl-2-methyloctanoate, bicyclo [2.2.1] -hept-2 -Ene-5,6-dicarboxylic acid 5-hydroxymethyl-bicyclo [2.2.1] -hept-2-ene, 5,6-di (hydroxymethyl) -bicyclo [2.2.1] -hept-2-ene, 5-hydroxy -I-propyl-bicyclo [2.2.1] -hept-2-ene, 5,6-dicarboxy-bicyclo [2.2.1] -hept-2-ene, bicyclo [2.2.1] -Hept-2-ene-5,6-dicarboxylic imide, 5-cyclopentyl-bicyclo [2.2.1] -hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1] -hept-2 -Ene, 5-cyclohexenyl-bicyclo [2.2.1] -hept-2-ene, 5-phenyl-bicyclo [2.2.1] -hept-2-ene, tricyclo [4.3.1 ^{2 , 5} . 0 ^1,6 ] -deca-3,7-diene (common name dicyclopentadiene), tricyclo [4.3.1 ^2,5 . 0 ^1,6 ] -dec-3-ene, tricyclo [4.4.1 ^2,5 . 0 ^1,6 ] -undeca-3,7-diene, tricyclo [4.4.1 ^2,5 . 0 ^1,6 ] -undeca-3,8-diene, tricyclo [4.4.1 ^2,5 . 0 ^1,6 ] -undec-3-ene, tetracyclo [7.4.1 ^10,13 . 0 ^1,9 . 0 ^2,7 ] -trideca-2,4,6-11-tetraene (also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene: common name methanotetrahydrofluorene), tetracyclo [8,4, 1 ^{11, 14,} 0 ^{1, 10,} 0 ^3,8] - tetradeca -3,5,7,12-11- tetraene (1,4-methano -1,4,4a, 5,10,10a- hexahydro Anthracene), tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene (also referred to as tetracyclododecene), 8-methyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-ethyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-methylidene-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-ethylidene-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-vinyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-propenyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-methoxycarbonyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-hydroxymethyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-carboxy-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-cyclopentyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-cyclohexyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-cyclohexenyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, 8-phenyl-tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] -dodec-3-ene, pentacyclo [6.5.1, ^1,8 . 1 ^3,6 . 0 ^2,7 . 0 ^{9, 13]} - pentadeca-3,10-diene, pentacyclo [7.4.1 ^3,6. 1 ^10,13 . 0 ^1,9 . 0 ^2,7] - pentadeca-4,11 the like dienes, but are not limited thereto. These norbornene monomers are used alone or in combination of two or more.

A ring-opening polymer of these norbornene monomers, or a ring-opening copolymer of a norbornene monomer and another monomer capable of ring-opening copolymerization is obtained by polymerizing monomer components in the presence of a ring-opening polymerization catalyst. Obtainable. As the ring-opening polymerization catalyst, for example, a catalyst comprising a metal halide such as ruthenium, rhodium, palladium, osmium, iridium, platinum, a nitrate or an acetylacetone compound, and a reducing agent, or titanium, vanadium, zirconium, tungsten A catalyst comprising a metal halide such as molybdenum or an acetylacetone compound and an organoaluminum compound can be used. The polymerization reaction is performed in a solvent or without a solvent, and is usually performed at a polymerization temperature of −50 ° C. to 100 ° C. and a polymerization pressure of 0 to 50 kg / cm ² . Examples of other monomers capable of ring-opening copolymerization with norbornene monomers include, but are not limited to, monocyclic cyclic olefin monomers such as cyclohexene, cycloheptene, and cyclooctene.

  The ring-opening polymer hydrogenated product of the norbornene-based monomer can be usually obtained by adding a hydrogenation catalyst to the polymerization solution of the ring-opening polymer and hydrogenating a carbon-carbon unsaturated bond. Although it does not specifically limit as a hydrogenation catalyst, Usually, a heterogeneous catalyst and a homogeneous catalyst are used.

Norbornene-based monomers, or addition (co) polymers of norbornene-based monomers and other monomers copolymerizable therewith, for example, monomer components in a solvent or without solvent, titanium, zirconium or vanadium compounds and organoaluminum In the presence of a catalyst comprising a compound, it can usually be obtained by (co) polymerization at a polymerization temperature of −50 ° C. to 100 ° C. and a polymerization pressure of 0 to 50 kg / cm ² .

Examples of other monomers copolymerizable with the norbornene monomer include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3- Ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, An α-olefin having 2 to 20 carbon atoms such as 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene;
Cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H -Cycloolefins such as indene;
Non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene;
However, it is not limited to these. Of these, α-olefins, particularly ethylene, are preferred.

  These other monomers copolymerizable with the norbornene-based monomer can be used alone or in combination of two or more. In the case of addition copolymerization of a norbornene monomer and another monomer copolymerizable therewith, the ratio of the structural unit derived from the norbornene monomer and the structural unit derived from the other monomer copolymerizable in the addition copolymer However, it is appropriately selected so that the weight ratio is usually 30:70 to 99: 1, preferably 50:50 to 97: 3, and more preferably 70:30 to 95: 5.

(2) Monocyclic olefin polymer
As the monocyclic olefin polymer, for example, an addition polymer of a monocyclic olefin monomer such as cyclohexene, cycloheptene, and cyclooctene can be used, but it is not limited thereto.

(3) Cyclic conjugated diene polymer As the cyclic conjugated diene polymer, for example, a polymer obtained by subjecting a cyclic conjugated diene monomer such as cyclopentadiene or cyclohexadiene to 1,2- or 1,4-addition polymerization, and Although the hydrogenated substance etc. can be used, it is not limited to these.

  The molecular weight of the norbornene-based polymer, monocyclic olefin-based polymer or cyclic conjugated diene-based polymer is appropriately selected according to the purpose of use, but is a cyclohexane solution (a toluene solution if the polymer resin does not dissolve). Polyisoprene or polystyrene-equivalent weight average molecular weight Mw measured by gel permeation chromatography, usually 5,000 to 1,000,000, preferably 8,000 to 800,000, more preferably 10,000 to When it is in the range of 500,000, the mechanical strength and molding processability of the molded body are often well-balanced and suitable.

(4) Vinyl alicyclic hydrocarbon polymer Examples of the vinyl alicyclic hydrocarbon polymer include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane, and hydrogenated products thereof; Hydrogenated products of aromatic ring portions of polymers of vinyl aromatic monomers such as styrene and α-methylstyrene can be used. In this case, a copolymer such as a random copolymer or a block copolymer of a vinyl alicyclic hydrocarbon polymer or a vinyl aromatic monomer and another monomer copolymerizable with these monomers. It may be a polymer and its hydrogenated product. Examples of the block copolymer include diblock, triblock, or more multiblock and gradient block copolymers, and are not particularly limited.

  The molecular weight of the vinyl alicyclic hydrocarbon polymer is appropriately selected according to the purpose of use, but it is determined by a gel permeation chromatographic method using a cyclohexane solution (a toluene solution when the polymer resin does not dissolve). When the weight average molecular weight Mw in terms of isoprene or polystyrene is usually in the range of 10,000 to 800,000, preferably 15,000 to 500,000, more preferably 20,000 to 300,000, In many cases, the mechanical strength and the moldability are well balanced.

  You may mix | blend various additives with a film (C) as needed. Examples of the additive include various resins having a water absorption rate exceeding 0.1%, such as various cellulose resins including triacetyl cellulose, and, for example, stabilizers such as an antioxidant, a light resistance stabilizer, and an ultraviolet absorber. An agent, an antistatic agent, etc. are mentioned, but there is no particular limitation as long as the object of the present invention is not impaired.

(Method for producing film (c))
As a method for producing the film (c), a melting method in which a resin is melted and a solution casting method in which a resin is dissolved in a solvent and cast to form a film can be used. For example, no solvent is used. A melting method capable of efficiently reducing the content of volatile components in the film is preferably used. The melting method is preferable because it is less expensive than the solution casting method and the like, has a high production rate, and does not use a solvent. Examples of the melting method include a method using a T die, a melt extrusion method such as an inflation method, a calendar method, a hot press method, and an injection molding method. Among them, a melt extrusion method using a T die that has a small thickness unevenness, can be easily processed into a film thickness of about 20 to 500 μm, and can reduce the absolute value and variation of the retardation is preferable.

  The conditions of the melt molding method are almost the same as those used for the polycarbonate resin having the same Tg. For example, in the melt extrusion method using a T-die, it is preferable to select conditions under which the resin can be gradually cooled at a resin temperature of about 240 to 300 ° C. and a take-up roll temperature of about 100 to 150 ° C. Further, in order to reduce surface defects such as die lines, it is necessary for the die to have a structure in which the staying portion is reduced as much as possible, and it is preferable to use a die that has as few scratches as possible in the die and lip. Further, the surface accuracy of the inside of the die and the lip can be further improved by polishing the surface as necessary.

  In producing the film (c), the film produced by the above-described melting method may be used without stretching, or may be stretched, for example, uniaxially stretched or biaxially stretched. By stretching, the retardation can be increased and appropriately adjusted.

By performing stretch molding in this way, in the film (c), the retardation R (590) at a wavelength of 590 nm can satisfy the relationship of the following formula (1).
R (590) ≧ 10 (nm) (1)

  When the film (c) satisfies the relationship of the formula (1), the film can function as a retardation plate, and a separate retardation plate is not necessary. In addition to the effects described above, by laminating such a film on the polarizer (a) to constitute a laminated polarizing plate, a polarizing plate having a simplified structure can be obtained by reducing the number of elements compared to the conventional case. Thus, the cost of the polarizing plate can be reduced and the light use efficiency can be improved.

  As a preferred method for obtaining such a film (c), the film may be stretched. For example, a sheet obtained by melt molding or the like can be stretched in a uniaxial direction or a biaxial direction. Retardation can be controlled by orienting molecules by stretching. The draw ratio is usually 1.3 to 10 times, preferably 1.5 to 8 times, and a predetermined retardation may be set within this range. If the draw ratio is too low, the absolute value of the retardation does not increase and may not reach a predetermined value, and if it is too high, it may break. Stretching is usually performed in a temperature range of Tg to Tg + 50 ° C., preferably Tg to Tg + 40 ° C. of the resin constituting the sheet. If the stretching temperature is too low, it will break, and if it is too high, the molecular orientation will not occur, so that the desired retardation may not be obtained.

  Patent Document 2 discloses a polarizing plate protective film made of 4-methyl-1-pentene, but does not mention that the retardation is adjusted to act as a retardation plate. Furthermore, there is no suggestion of such a device. In addition, the technique described in Patent Document 3 neither describes nor suggests that the retardation of the polarizing plate protective film is adjusted. Therefore, the techniques described in Patent Documents 2 and 3 have room for improvement from the viewpoint of reducing the number of polarizing plate elements.

  Moreover, the film (c) should just be able to function as a protective film of a polarizer (a) at least, and there is no restriction | limiting in particular in the film thickness, However, The film before extending | stretching is about 50-500 micrometers in film thickness. Is preferred. The film thickness after stretching is usually 10 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. If the film thickness is too small, it is difficult to impart sufficient mechanical strength to the film, while if it is too large, it is difficult to suppress optical loss and resin usage, and it was used for display elements. In some cases it is difficult to save space. By setting the film thickness within the above range, a protective film having an excellent balance between the two can be obtained.

  On the other hand, the thickness unevenness is preferably as small as possible, and is desirably within ± 8%, preferably within ± 6%, more preferably within ± 4% over the entire surface. When the thickness unevenness of the sheet is large, there is a possibility that the variation of the retardation of the stretched oriented film becomes large.

(4) Laminated Polarizing Plate The laminated polarizing plate of this embodiment has the above-mentioned film (b) laminated directly or indirectly on one surface of the above-described polarizer (a), and the other polarizer (a). The film (c) described above is laminated directly or indirectly on one surface.

  Here, “directly or indirectly laminated” means that the film (b) or (c) is directly laminated on the polarizer (a), and the film (b) or (c) and the polarizer (a). This includes both the case where an arbitrary layer is interposed between the two layers.

  In the polarizing film having the configuration of “cyclic olefin (co) polymer / polyvinyl alcohol / cyclic olefin (co) polymer” as described in Patent Document 1, the hygroscopicity of the cyclic olefin (co) polymer is high. Since it is remarkably low, it is difficult to sufficiently release the moisture contained in the polarizing film in the manufacturing process including bonding of each layer, a drying process, and the like. For this reason, the moisture content of the polarizing film in the obtained polarizing film becomes large, and the adhesive strength of each layer is insufficient, and the degree of polarization tends to decrease.

  In addition, in the polarizing film having the configuration of “Cyclic olefin (co) polymer / polyvinyl alcohol / triacetyl cellulose” described in Patent Document 1, first, a film made of different materials with polyvinyl alcohol interposed therebetween is used. Warpage is likely to occur in the manufacturing process. Further, triacetyl cellulose having high water absorption is used as the protective film, and the size of the triacetyl cellulose varies due to water absorption. This is also a cause of warping in the polarizing film having this configuration. Further, since triacetyl cellulose causes a change in optical properties due to a dimensional change, the degree of polarization of the polarizing film may be lowered.

  On the other hand, in this embodiment, a film made of 4-methyl-1-pentene or the like having low water absorption, high water vapor permeability, and high dimensional stability is used as a protective film for one surface of the polarizer (a). ing. For this reason, in the laminated polarizing plate using this film, drying becomes easy especially in the use of the polarizing plate protective film in which an aqueous adhesive is used. Therefore, compared with the polarizing film described in Patent Document 1, insufficient adhesive strength and warpage are unlikely to occur, and the stability of the polarization degree can be improved.

  In addition, as compared with a polarizing plate using triacetyl cellulose as one protective film, the laminated polarizing plate of the present embodiment is made of a film made of 4-methyl-1-pentene or the like, or a cyclic olefin (co) polymer. Since both films are materials with high dimensional stability, it is considered that warpage is suppressed.

  Patent Document 3 discloses a polarizing plate using a film made of a cyclic olefin (co) polymer as a protective film and a film having a water vapor transmission rate within a certain range, specifically, Triacetyl cellulose is used as a film having a water vapor permeability within a certain range. Therefore, it is difficult to solve the decrease in the degree of polarization of the polarizing film due to the dimensional variation that can occur by using triacetylcellulose.

  Patent Document 2 discloses a polarizing plate in which polarizing plate protective films made of poly-4-methyl-1-pentene having water vapor permeability, that is, high moisture permeability are laminated on both surfaces of a polarizing film. However, in such a polarizing plate, due to the high material permeability of each polarizing plate protective film, when laminating with other elements using a solvent-based adhesive or the like, the solvent from the adhesive or the like causes the polarizing plate protective film to There was a possibility that the polarizing film was transmitted and adversely affected.

  On the other hand, in this embodiment, by using a film made of a cyclic olefin (co) polymer having a high gas barrier property in combination with a film made of 4-methyl-1-pentene or the like, adverse effects on the polarizing film are reduced. Is done.

  As described above, the laminated polarizing plate of the present embodiment uses the conventional polarizing film by using a film made of 4-methyl-1-pentene and a film made of a cyclic olefin (co) polymer as a protective film. Compared to the plate, the dimensional stability is high, the adhesive strength between the protective film and the polarizer is insufficient, and the warp is hardly generated, and the stability of the polarization degree can be increased, which is useful.

  Furthermore, by using a film having a retardation adjusted within a certain range as the protective film, the protective film can also serve as a retardation plate, and the number of elements can be reduced.

  The liquid crystal display element of this embodiment has the laminated polarizing plate described above and a liquid crystal cell.

  A liquid crystal cell usually has a liquid crystal layer formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. This liquid crystal cell is further formed on a transparent electrode layer made of a transparent film containing a conductive material, a gas barrier layer provided to prevent air from passing through the liquid crystal layer, and the liquid crystal cell is imparted with kill resistance. An undercoat layer used for adhesion of the hard coat layer and the transparent electrode layer can be provided.

  As described above, in the laminated polarizing plate, the film (b) is directly or indirectly laminated on one surface of the polarizer (a), and the other surface of the polarizer (a) The film (c) is laminated directly or indirectly.

  Here, in the laminated polarizing plate, the film (c) may be disposed on the liquid crystal cell side with respect to the polarizer (a). With such a configuration, it is possible to reduce an adverse effect on the polarizer (a) that may be caused by the above-described adhesive when the film (c) and the liquid crystal cell are bonded.

  Moreover, you may make it arrange | position a film (c) on the opposite side to a liquid crystal cell on the basis of a polarizer (a). In this case, for example, a liquid crystal display element suitable for use in a humid environment can be obtained.

In addition, the display device of the present embodiment includes the above-described laminated polarizing plate and / or the above-described liquid crystal display element. That is, this embodiment includes the following aspects:
(1) A display device including the liquid crystal display element,
(2) a display device including the laminated polarizing plate and the liquid crystal display element,
(3) A display device comprising the laminated polarizing plate.

  The display device of (1) includes an optical compensation film in addition to the liquid crystal display element. The display device (2) further includes a laminated polarizing plate in addition to the display device (1). Moreover, as a display apparatus of (3), the display apparatus containing an organic EL element is mentioned.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the Example shown below in any meaning.

(Film A)
Copolymer of 4-methyl-1-pentene and a monomer having 12 and 14 carbon atoms (molar ratio is 12 carbon atoms: 14 carbon atoms = 50: 50) (molar ratio = 95: 5, MFR: 27 g) / 10 min, melting point 230 ° C., glass transition temperature 15 ° C., average refractive index 1.46, water absorption less than 0.01%), single screw extruder (diameter 40 mm), cylinder temperature 300 ° C., cast roll temperature Melt extrusion molding was performed at 30 ° C. to produce a film having a thickness of 200 μm, which was designated as film (A).

(Film B)
Random copolymer (molar ratio = 94: 6, MFR) of 4-methyl-1-pentene and a monomer having 16 and 18 carbon atoms (molar ratio is 16 carbon atoms: 18 carbon atoms = 50: 50). 22 g / 10 min, melting point 230 ° C., glass transition temperature 10 ° C., average refractive index 1.46, water absorption less than 0.01%), uniaxial extruder (diameter 40 mm), cylinder temperature 300 ° C., cast roll Melt extrusion molding was performed at a temperature of 30 ° C. to produce a film having a thickness of 200 μm, which was designated as film (B).

(Film C)
A ZEONOR film (brand: ZF14, film thickness 100 μm) manufactured by ZEON was used as the film (C).

(Film D)
A TAC film (film thickness: 80 μm) manufactured by Fuji Photo Film was used as the film (D).

(Film E)
A ZEONOR film (brand name: ZF14, film thickness: 100 μm) manufactured by Nippon Zeon was longitudinally uniaxially stretched at a temperature of 150 ° C. by a stretching machine to a film thickness of 80 μm to obtain a film (E).

(Film F)
A polycarbonate film manufactured by Teijin Chemicals (product name: Pure Ace, film thickness 100 μm) was longitudinally uniaxially stretched at a temperature of 180 ° C. with a stretching machine to a film thickness of 80 μm to obtain a film (F).

(Measurement method of retardation)
Retardation R (450) and R (590) at wavelengths of 450 nm and 590 nm of the films (A) to (F) are measured at 450 nm and 590 nm using a phase difference measuring device KOBRA of Oji Scientific Instruments Co., Ltd. It was determined by measuring the sample light incident on the sample plane at an incident angle of 0 °. For films with R (590) of 5 nm or more, the change in R (590) after standing in a constant temperature and humidity chamber of 60 ° C. × 90% relative humidity (RH) for 240 hours is less than 5% AA, % Or more was defined as CC.
The results are shown in Table 1.

(Measurement of water absorption)
The water absorption rate was measured according to JISK7209 method. First, the weight (W1) of a sample dried for 24 hours in a blower dryer set at 50 ° C. and cooled to room temperature in a desiccator was measured. Next, after immersing in pure water for 24 hours in an atmosphere at 25 ° C., the weight (W2) of the sample was carefully wiped off with a waste cloth. From these weights W1 and W2, the water absorption was determined from the following formula.
Water absorption (%) = (W2−W1) / W1 × 100
The measurement was performed at n = 3, and the arithmetic average value was defined as the water absorption rate of the resin. Table 1 shows the water absorption measurement results of the films (A) to (F).

(Measurement of adhesion)
The adhesion was measured with a universal testing machine (Strograph) manufactured by Toyo Seiki Seisakusho at a sample width of 1 cm, a pulling speed of 100 mm / min, and a pulling angle of 90 °. Table 2 shows the results of measuring the adhesion between each protective film and the polarizer film. When the adhesion is 300 g / cm or more, it is AA, and when it is less than 300 g, it is CC.

(Check for curl occurrence)
After lamination of the protective film and the polarizer film, the presence or absence of curling after the constant temperature and humidity test was checked. The results are shown in Table 2.

(Measurement of dimensional change)
The dimensional change was made by placing a 100 mm wide marked line in each of the longitudinal direction and the lateral direction of the obtained laminated polarizing plate, leaving it in a constant temperature and humidity chamber of 60 ° C. × 90% RH for 240 hours, It was determined by measuring the distance between the lines.

(Example 1)
The film (A), the iodine-containing PVA film that is a polarizer film, and the film (E) are mixed with a polyurethane-based aqueous adhesive (main agent: polyurethane resin (non-volatile content 35%), curing agent: polyisocyanate (non-volatile content 100). %) And the mixing ratio (wt%) were bonded using a main agent: curing agent = 100: 7) to form a laminated polarizing plate comprising a film (A) / polarizer film / film (E), and subsequently at 80 ° C. For 20 minutes at 60 ° C. for 3 days to produce a laminated polarizing plate.
When the adhesion of the laminated polarizing plate was measured, it was good at 590 g / cm.
Further, the laminated polarizing plate was left in a constant temperature and humidity chamber of 60 ° C. × 90% RH for 240 hours, but no noticeable curling occurred and the dimensional change was less than 0.1%.

(Example 2)
The film (B), the iodine-containing PVA film that is a polarizer film, and the film (E) are mixed with a polyurethane-based aqueous adhesive (main agent: polyurethane resin (non-volatile content 35%), curing agent: polyisocyanate (non-volatile content 100). %) And the mixing ratio (wt%) were bonded using a main agent: curing agent = 100: 7) to obtain a laminated polarizing plate comprising film (B) / polarizer film / film (E), and subsequently at 80 ° C. For 20 minutes at 60 ° C. for 3 days to produce a laminated polarizing plate.
When the adhesion of the laminated polarizing plate was measured, it was 650 g / cm, which was good.
Further, the laminated polarizing plate was left in a constant temperature and humidity chamber of 60 ° C. × 90% RH for 240 hours, but no noticeable curling occurred and the dimensional change was less than 0.1%.

(Comparative Example 1)
The film (D), the iodine-containing PVA film that is a polarizer film, and the film (E) are mixed with a polyurethane-based aqueous adhesive (main agent: polyurethane resin (non-volatile content 35%), curing agent: polyisocyanate (non-volatile content 100). %) And the mixing ratio (wt%) are laminated using a main agent: curing agent = 100: 7) to form a laminated polarizing plate comprising a film (D) / polarizer film / film (E), and subsequently at 80 ° C. For 20 minutes at 60 ° C. for 3 days to produce a laminated polarizing plate.
When the adhesion of the laminated polarizing plate was measured, it was 600 g / cm. However, when the laminated polarizing plate was left in a constant temperature and humidity chamber of 60 ° C. × 90% RH for 240 hours, curling occurred. This was thought to be because the dimensional change that was considered to be due to water absorption of the film (D) was larger than that of the film (E).

(Comparative Example 2)
The film (C), the iodine-containing PVA film as a polarizer film, and the film (E) are mixed with a polyurethane-based aqueous adhesive (main agent: polyurethane resin (non-volatile content 35%), curing agent: polyisocyanate (non-volatile content 100). %) And the mixing ratio (wt%) were bonded using a main agent: curing agent = 100: 7) to form a laminated polarizing plate comprising film (C) / polarizer film / film (E), and subsequently at 80 ° C. For 20 minutes at 60 ° C. for 3 days to produce a laminated polarizing plate.
When the adhesion of the laminated polarizing plate was measured, it was as small as less than 50 g / cm, indicating poor adhesion. The cause was that the adhesive was not sufficiently dry.

(Comparative Example 3)
The film (D), the iodine-containing PVA film that is a polarizer film, and the film (F) are mixed with a polyurethane-based aqueous adhesive (main agent: polyurethane resin (non-volatile content 35%), curing agent: polyisocyanate (non-volatile content 100). %) And the mixing ratio (wt%) are laminated using a main agent: curing agent = 100: 7) to form a laminated polarizing plate comprising film (D) / polarizer film / film (F), and subsequently at 80 ° C. For 20 minutes at 60 ° C. for 3 days to produce a laminated polarizing plate.
When the adhesion of the laminated polarizing plate was measured, it was good at 610 g / cm. However, when the laminated polarizing plate was left in a constant temperature and humidity chamber of 60 ° C. × 90% RH for 240 hours, curling occurred.

Claims (6)

  A high structure having a structural unit derived from at least one selected from 4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-butene on one surface of the polarizer (a) A film (b) containing molecules is directly or indirectly laminated, and a film (c) containing a polymer having a structural unit derived from a cyclic olefin is directly formed on the other surface of the polarizer (a). Or the laminated polarizing plate laminated | stacked indirectly. In the laminated polarizing plate of Claim 1,
A laminated polarizing plate in which in-plane retardation R (590) of the film (c) at a wavelength of 590 nm satisfies the relationship of the following formula (1).
R (590) ≧ 10 (nm) (1) In the laminated polarizing plate according to claim 1 or 2,
The laminated polarizing plate in which the polarizer (a) contains iodine and / or a dichroic dye and a polyvinyl alcohol resin.   The liquid crystal display element which has a laminated polarizing plate of any one of Claim 1 to 3, and a liquid crystal cell. The liquid crystal display element according to claim 4.
The liquid crystal display element by which the said film (c) is arrange | positioned at the said liquid crystal cell side on the basis of the said polarizer (a).   The display apparatus which has a laminated polarizing plate of any one of Claim 1 to 3, and / or the liquid crystal display element of Claim 4 or 5.