JP4461795B2 - Optical laminate and method for producing optical laminate - Google Patents
Optical laminate and method for producing optical laminate Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims description 32
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 239000010410 layer Substances 0.000 claims description 71
- 229920000642 polymer Polymers 0.000 claims description 33
- 238000002834 transmittance Methods 0.000 claims description 32
- 125000002723 alicyclic group Chemical group 0.000 claims description 29
- 239000006097 ultraviolet radiation absorber Substances 0.000 claims description 25
- 239000002952 polymeric resin Substances 0.000 claims description 21
- 229920003002 synthetic resin Polymers 0.000 claims description 21
- 229920005989 resin Polymers 0.000 claims description 20
- 239000011347 resin Substances 0.000 claims description 20
- 239000002344 surface layer Substances 0.000 claims description 19
- 239000006096 absorbing agent Substances 0.000 claims description 17
- 238000001816 cooling Methods 0.000 claims description 16
- 230000001681 protective effect Effects 0.000 claims description 13
- 238000005266 casting Methods 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000000034 method Methods 0.000 description 34
- JFNLZVQOOSMTJK-KNVOCYPGSA-N norbornene Chemical compound C1[C@@H]2CC[C@H]1C=C2 JFNLZVQOOSMTJK-KNVOCYPGSA-N 0.000 description 23
- 239000004973 liquid crystal related substance Substances 0.000 description 19
- 239000000178 monomer Substances 0.000 description 12
- 238000005259 measurement Methods 0.000 description 8
- 239000003795 chemical substances by application Substances 0.000 description 7
- 230000007774 longterm Effects 0.000 description 7
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- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 238000000465 moulding Methods 0.000 description 6
- 230000009477 glass transition Effects 0.000 description 5
- -1 saturated alicyclic hydrocarbon Chemical class 0.000 description 5
- 238000004040 coloring Methods 0.000 description 4
- 238000013329 compounding Methods 0.000 description 4
- 150000001924 cycloalkanes Chemical group 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- FQUNFJULCYSSOP-UHFFFAOYSA-N bisoctrizole Chemical compound N1=C2C=CC=CC2=NN1C1=CC(C(C)(C)CC(C)(C)C)=CC(CC=2C(=C(C=C(C=2)C(C)(C)CC(C)(C)C)N2N=C3C=CC=CC3=N2)O)=C1O FQUNFJULCYSSOP-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
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- 230000006866 deterioration Effects 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
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- 150000004678 hydrides Chemical class 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
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- 239000000758 substrate Substances 0.000 description 3
- LCSLWNXVIDKVGD-KQQUZDAGSA-N (3e,7e)-deca-3,7-diene Chemical compound CC\C=C\CC\C=C\CC LCSLWNXVIDKVGD-KQQUZDAGSA-N 0.000 description 2
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 2
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
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- 229910052740 iodine Inorganic materials 0.000 description 2
- 239000011630 iodine Substances 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
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- 238000006116 polymerization reaction Methods 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 125000001424 substituent group Chemical group 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- HECLRDQVFMWTQS-RGOKHQFPSA-N 1755-01-7 Chemical compound C1[C@H]2[C@@H]3CC=C[C@@H]3[C@@H]1C=C2 HECLRDQVFMWTQS-RGOKHQFPSA-N 0.000 description 1
- UWSMKYBKUPAEJQ-UHFFFAOYSA-N 5-Chloro-2-(3,5-di-tert-butyl-2-hydroxyphenyl)-2H-benzotriazole Chemical compound CC(C)(C)C1=CC(C(C)(C)C)=CC(N2N=C3C=C(Cl)C=CC3=N2)=C1O UWSMKYBKUPAEJQ-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- 229920002284 Cellulose triacetate Polymers 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical class O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 150000001336 alkenes Chemical group 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000003373 anti-fouling effect Effects 0.000 description 1
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- RWCCWEUUXYIKHB-UHFFFAOYSA-N benzophenone Chemical compound C=1C=CC=CC=1C(=O)C1=CC=CC=C1 RWCCWEUUXYIKHB-UHFFFAOYSA-N 0.000 description 1
- 239000012965 benzophenone Substances 0.000 description 1
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 description 1
- 239000012964 benzotriazole Substances 0.000 description 1
- WXNRYSGJLQFHBR-UHFFFAOYSA-N bis(2,4-dihydroxyphenyl)methanone Chemical compound OC1=CC(O)=CC=C1C(=O)C1=CC=C(O)C=C1O WXNRYSGJLQFHBR-UHFFFAOYSA-N 0.000 description 1
- SODJJEXAWOSSON-UHFFFAOYSA-N bis(2-hydroxy-4-methoxyphenyl)methanone Chemical compound OC1=CC(OC)=CC=C1C(=O)C1=CC=C(OC)C=C1O SODJJEXAWOSSON-UHFFFAOYSA-N 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- OCWYEMOEOGEQAN-UHFFFAOYSA-N bumetrizole Chemical compound CC(C)(C)C1=CC(C)=CC(N2N=C3C=C(Cl)C=CC3=N2)=C1O OCWYEMOEOGEQAN-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
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- 210000002858 crystal cell Anatomy 0.000 description 1
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- 125000004122 cyclic group Chemical group 0.000 description 1
- 150000001925 cycloalkenes Chemical group 0.000 description 1
- GVRWIAHBVAYKIZ-UHFFFAOYSA-N dec-3-ene Chemical compound CCCCCCC=CCC GVRWIAHBVAYKIZ-UHFFFAOYSA-N 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
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- 238000009792 diffusion process Methods 0.000 description 1
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- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 239000012778 molding material Substances 0.000 description 1
- 125000002950 monocyclic group Chemical group 0.000 description 1
- 125000003518 norbornenyl group Chemical group C12(C=CC(CC1)C2)* 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
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- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
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- 239000003381 stabilizer Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- XBFJAVXCNXDMBH-UHFFFAOYSA-N tetracyclo[6.2.1.1(3,6).0(2,7)]dodec-4-ene Chemical compound C1C(C23)C=CC1C3C1CC2CC1 XBFJAVXCNXDMBH-UHFFFAOYSA-N 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
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Landscapes
- Liquid Crystal (AREA)
- Laminated Bodies (AREA)
- Polarising Elements (AREA)
Description
本発明は、液晶表示装置等に用いられる光学積層体に関し、さらに詳しくは液晶表示装置に使用したときに表示むらの小さい光学積層体に関する。 The present invention relates to an optical laminate used for a liquid crystal display device and the like, and more particularly to an optical laminate having a small display unevenness when used in a liquid crystal display device.
液晶表示装置に用いる偏光板は、偏光子の両面に偏光板保護フィルムを積層させた積層体からなり、透明電極を形成する２枚の電極基板間に液晶を封入した液晶セルの片側もしくは両側に貼付けて使用される。偏光子には、ポリビニルアルコールを溶液成膜したフィルムをホウ酸溶液中で延伸し、ヨウ素又は二色性色素を吸着させたものが使用されている。 A polarizing plate used for a liquid crystal display device is composed of a laminate in which polarizing plate protective films are laminated on both sides of a polarizer, and is disposed on one or both sides of a liquid crystal cell in which liquid crystal is sealed between two electrode substrates forming a transparent electrode. Used by pasting. As the polarizer, a film in which a film of polyvinyl alcohol is formed into a film is stretched in a boric acid solution to adsorb iodine or a dichroic dye.
偏光板保護フィルムとしては、トリアセチルセルロース（以下ＴＡＣという）が一般に広く使用されているが、耐熱性、耐湿性が十分でなく、高温もしくは高湿雰囲気下で長時間使用すると、偏光度の著しい低下、偏光子と保護フィルムとの分離、ＴＡＣの加水分解による透明性の低下等によって、偏光板の性能が低下するため、ＬＣＤに用いた場合には画質の低下が起こる。また、ＬＣＤに組み込むまでもなく、高温高湿下での耐久性試験において著しい品質低下を起こすことがあった。 As a polarizing plate protective film, triacetyl cellulose (hereinafter referred to as TAC) is generally widely used. However, heat resistance and moisture resistance are not sufficient, and when used for a long time in a high temperature or high humidity atmosphere, the degree of polarization is remarkable. The performance of the polarizing plate decreases due to the decrease, separation of the polarizer and the protective film, decrease in transparency due to hydrolysis of TAC, and the like, so that when used in an LCD, the image quality deteriorates. In addition, there is a case where the quality is significantly deteriorated in the durability test under high temperature and high humidity without being incorporated into the LCD.
これらの問題を解決するために、当出願人は、特許文献１において、ノルボルネン系樹脂からなる偏光板保護フィルムを提案している。
しかしながら、ノルボルネン系樹脂フィルムには、１）紫外線を吸収する性質がないため、液晶又は偏光膜を紫外線の劣化から保護することができない；２）紫外線吸収剤を配合して押出成形する場合は高温での成形となるため、金型から樹脂が吐出すると同時に揮発した紫外線吸収剤が冷却ロールに付着し、さらにフィルムに液状もしくは固形状で転写されるため外観不良を引き起こす；３）揮発した紫外線吸収剤が金型等の設備に付着し、固化もしくは液化した後、フィルム又は金属ロールに移行するため、フィルムの外観不良を引き起こす；等の問題がある。
In order to solve these problems, the present applicant has proposed a polarizing plate protective film made of a norbornene-based resin in Patent Document 1.
However, norbornene-based resin films have the following characteristics: 1) Since they do not absorb ultraviolet rays, the liquid crystal or polarizing film cannot be protected from deterioration of ultraviolet rays; Since the resin is discharged from the mold, the volatilized UV absorber adheres to the cooling roll and is transferred to the film in liquid or solid form, causing poor appearance; 3) Volatile UV absorption Since the agent adheres to equipment such as a mold and is solidified or liquefied, the agent moves to a film or a metal roll, thereby causing problems such as poor appearance of the film.
そこで、特許文献２において、波長３８０ｎｍ以下の紫外線透過率が４０％以下であることを特徴とするノルボルネン系樹脂フィルム（請求項１）、中間層の両側に表面層が積層された３層積層体からなり、少なくとも中間層には紫外線吸収剤が配合されており、中間層の紫外線吸収剤濃度が両表面層より高く設定されていることを特徴とする請求項１記載のノルボルネン系樹脂フィルム（請求項２）が記載されている。
そして、特許文献２によれば、ノルボルネン系樹脂に紫外線吸収性を付与することにより、液晶や偏光膜を紫外線から保護できる；一方の層または両側の表面層の紫外線吸収剤濃度を低くすることにより、押出成形時にロール汚れのない成形が可能となる；と記載されている。
Accordingly, in Patent Document 2, a norbornene-based resin film having an ultraviolet transmittance of 40% or less at a wavelength of 380 nm or less (Claim 1), a three-layer laminate in which surface layers are laminated on both sides of an intermediate layer The norbornene-based resin film according to claim 1, wherein an ultraviolet absorber is blended in at least the intermediate layer, and the concentration of the ultraviolet absorber in the intermediate layer is set higher than both surface layers. Item 2) is described.
According to Patent Document 2, it is possible to protect a liquid crystal or a polarizing film from ultraviolet rays by providing the norbornene resin with ultraviolet absorptivity; by reducing the concentration of the ultraviolet absorber in one or both surface layers. In addition, it is described that molding without roll contamination is possible during extrusion molding.
しかしながら、特許文献２に記載のフィルムを偏光板保護フィルムとして液晶表示装置に実装した場合、色調のばらつきが発生したり、実装時には表示むらがなくても長時間使用後において表示むらが発生したりする問題があり、さらなる改善が求められている。 However, when the film described in Patent Document 2 is mounted on a liquid crystal display device as a polarizing plate protective film, variations in color tone occur, or even when there is no display unevenness during mounting, display unevenness may occur after a long period of use. There is a problem, and further improvement is demanded.
従って、本発明の目的は、長期間使用においても紫外線透過率の変化が少なく、液晶表示に実装したときに表示むらや着色のない光学積層体を提供することである。 Accordingly, an object of the present invention is to provide an optical laminate that has little change in ultraviolet transmittance even after long-term use and has no display unevenness or coloring when mounted on a liquid crystal display.
かくして、前記課題を解決する手段として、
（１）中間層の両側に表面層が積層されてなる光学積層体であって、各層の樹脂成分が脂環式構造を有する重合体樹脂であり、該中間層が以下の［１］及び［２］の要件を満たし、
前記積層体の波長３８０ｎｍにおける光線透過率が３〜９％で、３７０ｎｍにおける光線透過率が２％以下で、波長４２０〜７８０ｎｍにおける光線透過率が８５％以上で、かつ波長３８５〜３９５ｎｍにおける光線透過率の変化率が４％／ｎｍ以上であり、
該中間層の厚さのばらつきが全面で±１μｍ以内であり、
該中間層の厚さが３０〜４０μｍであり、
該表面層の厚さが５〜１０μｍである光学積層体、
［１］中間層の紫外線吸収剤の含有量が０．５〜２．５重量％である、
［２］中間層における紫外線吸収剤の濃度のばらつきが全面で±０．１％以内である；
（２）偏光板保護フィルムとして用いられる請求項１記載の光学積層体；
（３）前記積層体の波長３８０ｎｍにおける光線透過率が３．２％以上である請求項１又は２に記載の光学積層体；
（４）マルチマニホールドを用いた共押出により製造された請求項１〜３のいずれか一項に記載の光学積層体；
（５）該表面層に紫外線吸収剤を含有しない請求項１〜４のいずれか一項に記載の光学積層体；
及び
（６）請求項１〜５のいずれか一項に記載の光学積層体の製造方法であって、
ダイスを有する押出機の前記ダイスから前記の脂環式構造を有する重合体樹脂を共押出し、冷却ロール上にキャストする工程を有し、
（１）前記押出機内に目開きが２０μｍ以下のポリマーフィルターが設けられ、
（２）前記押出機のギヤポンプを５ｒｐｍ以上で回転させ、
（３）前記ダイス周りに囲い手段が配置され、
（４）エアギャップが２００ｍｍ以下とされ、
（５）前記冷却ロール上にキャストする際にエッジピニングを行い、
（６）前記押出機が二軸押出機又はスクリュー形式がダブルフライト型の単軸押出機である、光学積層体の製造方法
がそれぞれ提供される。
Thus, as a means for solving the above problems,
(1) An optical laminate in which a surface layer is laminated on both sides of an intermediate layer, wherein the resin component of each layer is a polymer resin having an alicyclic structure, and the intermediate layer comprises the following [1] and [ 2]
The laminate has a light transmittance of 3 to 9% at a wavelength of 380 nm, a light transmittance of 370 nm at 2% or less, a light transmittance at a wavelength of 420 to 780 nm of 85% or more, and a light transmission at a wavelength of 385 to 395 nm. der rate of change rate of 4% / nm or more is,
The thickness variation of the intermediate layer is within ± 1 μm on the entire surface,
The thickness of the intermediate layer is 30-40 μm,
Optical stack thickness of the surface layer is Ru 5~10μm der,
[1] The content of the UV absorber in the intermediate layer is 0.5 to 2.5% by weight.
[2] Variation in the concentration of the UV absorber in the intermediate layer is within ± 0.1% over the entire surface;
(2) according to claim 1 Symbol placement of the optical stack is used as a polarizing plate protective film;
( 3 ) The optical laminate according to claim 1 or 2 , wherein the laminate has a light transmittance of 3.2% or more at a wavelength of 380 nm.
( 4 ) The optical laminate according to any one of claims 1 to 3 , which is produced by coextrusion using a multi-manifold;
( 5 ) The optical layered product according to any one of claims 1 to 4 , wherein the surface layer does not contain an ultraviolet absorber .
及 beauty <br/> (6) The method for producing an optical laminate according to any one of claims 1 to 5
The polymeric resin coextrusion city from the die of an extruder having a die having an alicyclic structure described above, have a step of casting onto a chill roll,
(1) A polymer filter having an opening of 20 μm or less is provided in the extruder,
(2) The gear pump of the extruder is rotated at 5 rpm or more,
(3) An enclosure means is disposed around the die,
(4) The air gap is 200 mm or less,
(5) Perform edge pinning when casting on the cooling roll,
(6) The manufacturing method of the optical laminated body whose said extruder is a twin screw extruder or a screw type is a double flight type single screw extruder, respectively is provided.
本発明によれば、長期間使用後の紫外線透過率の変化が面内で均一とすることができるので、本発明の光学積層体を光学部材、特に偏光板保護フィルムとして液晶表示装置に実装すると、液晶表示装置の表示むらや着色を小さくすることができる。 According to the present invention, since the change in ultraviolet transmittance after long-term use can be made uniform in the plane, when the optical laminate of the present invention is mounted on a liquid crystal display device as an optical member, particularly a polarizing plate protective film. The display unevenness and coloring of the liquid crystal display device can be reduced.
本発明に使用する脂環式構造を有する重合体樹脂は、主鎖及び／又は側鎖に脂環式構造を有するものであり、機械強度、耐熱性などの観点から、主鎖に脂環式構造を含有するものが好ましい。 The polymer resin having an alicyclic structure used in the present invention has an alicyclic structure in the main chain and / or side chain, and is alicyclic in the main chain from the viewpoint of mechanical strength, heat resistance and the like. Those containing a structure are preferred.
脂環式構造としては、飽和脂環炭化水素（シクロアルカン）構造、不飽和脂環炭化水素（シクロアルケン）構造などが挙げられるが、機械強度、耐熱性などの観点から、シクロアルカン構造やシクロアルケン構造が好ましく、中でもシクロアルカン構造が最も好ましい。脂環式構造を構成する炭素原子数には、格別な制限はないが、通常４〜３０個、好ましくは５〜２０個、より好ましくは５〜１５個の範囲であるときに、機械強度、耐熱性、及び積層体の成形性の特性が高度にバランスされ、好適である。本発明に使用される脂環式構造を有する重合体樹脂中の脂環式構造を含有してなる繰り返し単位の割合は、使用目的に応じて適宜選択すればよいが、好ましくは５０重量％以上、さらに好ましくは７０重量％以上、もっとも好ましくは９０重量％以上である。脂環式構造を有する重合体中の脂環式構造を有する繰り返し単位の割合がこの範囲にあると積層体の透明性および耐熱性の観点から好ましい。 Examples of alicyclic structures include saturated alicyclic hydrocarbon (cycloalkane) structures and unsaturated alicyclic hydrocarbon (cycloalkene) structures. From the viewpoint of mechanical strength and heat resistance, cycloalkane structures and cycloalkane structures can be used. Alkene structures are preferred, with cycloalkane structures being most preferred. 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 in the mechanical strength, The properties of heat resistance and moldability of the laminate are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the polymer resin having an alicyclic structure used in the present invention may be appropriately selected according to the purpose of use, but is preferably 50% by weight or more. More preferably, it is 70% by weight or more, and most preferably 90% by weight or more. When the ratio of the repeating unit having an alicyclic structure in the polymer having an alicyclic structure is within this range, it is preferable from the viewpoint of transparency and heat resistance of the laminate.
脂環式構造を有する重合体樹脂は、具体的には、（１）ノルボルネン系重合体、（２）単環の環状オレフィン系重合体、（３）環状共役ジエン系重合体、（４）ビニル脂環式炭化水素重合体、及びこれらの水素化物などが挙げられる。これらの中でも、透明性や成形性の観点から、ノルボルネン系重合体がより好ましい。
ノルボルネン系重合体としては、具体的にはノルボルネン系モノマーの開環重合体、ノルボルネン系モノマーと開環共重合可能なその他のモノマーとの開環共重合体、及びそれらの水素化物、ノルボルネン系モノマーの付加重合体、ノルボルネン系モノマーと共重合可能なその他のモノマーとの付加共重合体などが挙げられる。これらの中でも、透明性の観点から、ノルボルネン系モノマーの開環（共）重合体水素化物が最も好ましい。
上記の脂環式構造を有する重合体樹脂は、例えば特開２００２−３２１３０２号公報などに開示されている公知の重合体から選ばれる。
Specifically, the polymer resin having an alicyclic structure includes (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrides thereof. Among these, norbornene-based polymers are more preferable from the viewpoints of transparency and moldability.
Specific examples of the norbornene-based polymer include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, hydrides thereof, and norbornene-based monomers. And addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, from the viewpoint of transparency, a ring-opening (co) polymer hydride of a norbornene-based monomer is most preferable.
The polymer resin having the alicyclic structure is selected from known polymers disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-321302.
本発明に使用する脂環式構造を有する重合体樹脂に好適に用いられるノルボルネン系重合体の中でも、繰り返し単位として、Ｘ：ビシクロ［３．３．０］オクタン−２，４−ジイル−エチレン構造と、Ｙ：トリシクロ［４．３．０．１２，５］デカン−７，９−ジイル−エチレン構造とを有し、これらの繰り返し単位の含有量が、ノルボルネン系重合体の繰り返し単位全体に対して９０重量％以上であり、かつ、Ｘの含有割合とＹの含有割合との比が、Ｘ：Ｙの重量比で１００：０〜４０：６０であるものが好ましい。このような樹脂を用いることにより、長期的に寸法変化がなく、光学特性の安定性に優れる積層体を得ることができる。 Among norbornene polymers suitably used for the polymer resin having an alicyclic structure used in the present invention, as a repeating unit, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure And Y: tricyclo [4.3.0.1 2,5 ] decane-7,9-diyl-ethylene structure, and the content of these repeating units is in the entire repeating unit of the norbornene polymer. On the other hand, it is preferably 90% by weight or more and the ratio of the content ratio of X and the content ratio of Y is 100: 0 to 40:60 in terms of the weight ratio of X: Y. By using such a resin, it is possible to obtain a laminate having no dimensional change over a long period of time and excellent optical property stability.
ポリマーとしてＸの構造を繰り返し単位として有するモノマーとしては、ノルボルネン環に五員環が結合した構造を有するノルボルネン系単量体が挙げられ、より具体的には、トリシクロ[４．３．０．１２，５]デカ−３，７−ジエン（慣用名：ジシクロペンタジエン）及びその誘導体（環に置換基を有するもの）、７，８−ベンゾトリシクロ[４．３．０．１０，５]デカ−３−エン（慣用名：メタノテトラヒドロフルオレン）、及びその誘導体が挙げられる。
また、ポリマーとしてＹの構造を繰り返し単位として有するモノマーとしては、テトラシクロ[４．４．０．１２，５．１７，１０]デカ−３，７−ジエン（慣用名：テトラシクロドデセン）及びその誘導体（環に置換基を有するもの）が挙げられる。
Examples of the monomer having the X structure as a repeating unit as a polymer include norbornene monomers having a structure in which a 5-membered ring is bonded to a norbornene ring. More specifically, tricyclo [4.3.0.1 2,5] deca-3,7-diene (trivial name: dicyclopentadiene) and their derivatives (those having a substituent on the ring), 7,8-tricyclo [4.3.0.1 0, 5 ] Dec-3-ene (common name: methanotetrahydrofluorene) and its derivatives.
Moreover, as a monomer which has a structure of Y as a repeating unit as a polymer, tetracyclo [4.4.0.1 2,5 . 1 7,10 ] deca-3,7-diene (common name: tetracyclododecene) and derivatives thereof (those having a substituent in the ring).
このようなノルボルネン系重合体を得る手段としては、具体的にはａ）ポリマーとして前記Ｘの構造を繰り返し単位として有することができるモノマーと、ポリマーとして前記Ｙの構造を繰り返し単位として有することができるモノマーとの共重合比でコントロールして重合し、必要に応じてポリマー中の不飽和結合を水素化する方法や、ｂ）前記Ｘの構造を繰り返し単位として有するポリマーと、前記Ｙの構造を繰り返し単位として有するポリマーとのブレンド比でコントロールする方法が挙げられる。 As a means for obtaining such a norbornene polymer, specifically, a) a monomer that can have the X structure as a repeating unit as a polymer, and a Y structure that can have the repeating structure as a polymer. Polymerization by controlling the copolymerization ratio with the monomer and, if necessary, hydrogenating unsaturated bonds in the polymer, b) repeating the polymer having the X structure as a repeating unit and the Y structure The method of controlling by the blend ratio with the polymer which has as a unit is mentioned.
本発明において、使用する脂環式構造を有する重合体樹脂の分子量は、溶媒としてシクロヘキサン（重合体樹脂が溶解しない場合はトルエン）を用いたゲル・パーミエーション・クロマトグラフィー（以下、「ＧＰＣ」と略す。）で測定したポリイソプレン換算の重量平均分子量（Ｍｗ）で、通常５，０００〜１００，０００、好ましくは８，０００〜８０，０００、より好ましくは１０，０００〜５０，０００である。重量平均分子量がこのような範囲にあるときに、積層体の機械的強度及び成形加工性が高度にバランスされ好適である。 In the present invention, the molecular weight of the polymer resin having an alicyclic structure used is gel permeation chromatography (hereinafter referred to as “GPC”) using cyclohexane (toluene when the polymer resin is not dissolved) as a solvent. The weight average molecular weight (Mw) in terms of polyisoprene measured in (Abbreviated) is usually 5,000 to 100,000, preferably 8,000 to 80,000, and more preferably 10,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the laminate are highly balanced, which is preferable.
脂環式構造を有する重合体樹脂の分子量分布（重量平均分子量（Ｍｗ）／数平均分子量（Ｍｎ））は特に制限されないが、通常１．０〜１０．０、好ましくは１．０〜４．０、より好ましくは１．２〜３．５の範囲である。 The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polymer resin having an alicyclic structure is not particularly limited, but is usually 1.0 to 10.0, preferably 1.0 to 4. 0, more preferably in the range of 1.2 to 3.5.
脂環式構造を有する重合体樹脂は、その分子量２，０００以下の樹脂成分（すなわち、オリゴマー成分）の含有量が５重量％以下、好ましくは３重量％以下、より好ましくは２重量％以下である。オリゴマー成分の量が多いと積層体を製造する際に、中間層と表面層それぞれに微細な凹凸が発生したり、各層において厚さむらが生じたりして面精度が悪くなる可能性がある。 The polymer resin having an alicyclic structure has a content of a resin component having a molecular weight of 2,000 or less (that is, an oligomer component) of 5% by weight or less, preferably 3% by weight or less, more preferably 2% by weight or less. is there. When the amount of the oligomer component is large, when the laminate is produced, fine irregularities may be generated in each of the intermediate layer and the surface layer, or thickness unevenness may occur in each layer, which may deteriorate the surface accuracy.
オリゴマー成分の量を低減するためには、重合触媒や水素化触媒の選択；重合反応や水素化反応などの反応条件；樹脂を成形用材料としてペレット化する工程における温度条件；などを最適化すればよい。オリゴマーの成分量は、シクロヘキサン（重合体樹脂が溶解しない場合はトルエン）を用いたゲル・パーミエーション・クロマトグラフィーによって測定することができる。 In order to reduce the amount of oligomer components, the selection of polymerization catalyst and hydrogenation catalyst; reaction conditions such as polymerization reaction and hydrogenation reaction; temperature conditions in the process of pelletizing resin as a molding material; That's fine. The amount of the oligomer component can be measured by gel permeation chromatography using cyclohexane (toluene if the polymer resin does not dissolve).
本発明の積層体は、波長３８０ｎｍにおける光線透過率が３〜９％で、波長３７０ｎｍにおける光線透過率が２％以下で、波長４２０〜７８０ｎｍにおける光線透過率が８５％以上で、かつ波長３８５〜３９５ｎｍにおける光線透過率の変化率が４％／ｎｍ以上であり、好ましくは波長３７０ｎｍにおける光線透過率が１％以下で、波長３８０ｎｍにおける光線透過率が３．５〜６％で、波長４２０〜７８０ｎｍにおける光線透過率が８８％以上で、かつ波長３８５〜３９５ｎｍにおける光線透過率の変化率が４％／ｎｍ以上である。
本発明において、波長３８０ｎｍにおける光線透過率が３％未満であると積層体全体がかなり黄色みを帯びてしまい、液晶表示装置などの表示装置に実装したとき、特に長期間使用した場合に着色してしまう。逆に９％を超えると紫外線により偏光子が変化し偏光度が低下する。波長４２０〜７８０ｎｍにおける光線透過率が８５％未満であると液晶表示装置などの表示装置に実装したとき、特に長期間使用した場合の輝度が低下する。波長３８５〜３９５ｎｍにおける光線透過率の変化率が４％／ｎｍ未満であると積層体の着色がかなり強くなる。
上記光線透過率は、ＪＩＳ Ｋ０１１５に準拠して、分光光度計を用いて測定することができる。
The laminate of the present invention has a light transmittance at a wavelength of 380 nm of 3 to 9%, a light transmittance at a wavelength of 370 nm of 2% or less, a light transmittance at a wavelength of 420 to 780 nm of 85% or more, and a wavelength of 385 to 385 nm. The change rate of the light transmittance at 395 nm is 4% / nm or more, preferably the light transmittance at a wavelength of 370 nm is 1% or less, the light transmittance at a wavelength of 380 nm is 3.5 to 6%, and the wavelength is 420 to 780 nm. And the change rate of the light transmittance at a wavelength of 385 to 395 nm is 4% / nm or more.
In the present invention, when the light transmittance at a wavelength of 380 nm is less than 3%, the entire laminate is considerably yellowish, and when mounted on a display device such as a liquid crystal display device, it is colored particularly when used for a long time. End up. On the other hand, if it exceeds 9%, the polarizer changes due to ultraviolet rays, and the degree of polarization decreases. When the light transmittance at a wavelength of 420 to 780 nm is less than 85%, when mounted on a display device such as a liquid crystal display device, the luminance particularly when used for a long period of time decreases. When the rate of change in light transmittance at a wavelength of 385 to 395 nm is less than 4% / nm, coloring of the laminate becomes considerably strong.
The light transmittance can be measured using a spectrophotometer according to JIS K0115.
紫外線吸収剤としては、ベンゾフェノン系紫外線吸収剤、ベンゾトリアゾール系紫外線吸収剤、アクリロニトリル系紫外線吸収剤等公知のものが使用可能である。中でも、紫外線吸収剤としては、２，２´−メチレンビス（４−（１，１，３，３−テトラメチルブチル）−６−（２Ｈ−ベンゾトリアゾール−２−イル）フェノール）、２−（２´−ヒドロキシ−３´−ｔｅｒｔ−ブチル−５´−メチルフェニル）−５−クロロベンゾトリアゾール、２，４−ジ−ｔｅｒｔ−ブチル−６−（５−クロロベンゾトリアゾール−２−イル）フェノール、２，２´−ジヒドロキシ−４，４´−ジメトキシベンゾフェノン、２，２´，４，４´−テトラヒドロキシベンゾフェノン等が好適に用いられる。これらの中でも、特に２，２´−メチレンビス（４−（１，１，３，３−テトラメチルブチル）−６−（２Ｈ−ベンゾトリアゾール−２−イル）フェノール）が好ましい。 As the ultraviolet absorber, known ones such as a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and an acrylonitrile ultraviolet absorber can be used. Among them, as the ultraviolet absorber, 2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2 '-Hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) phenol, 2 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone and the like are preferably used. Among these, 2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol) is particularly preferable.
上記紫外線吸収剤を含有させる方法としては、紫外線吸収剤を予め脂環式構造を有する重合体樹脂中に配合する方法；紫外線吸収剤を高濃度に含有するマスターバッチを用いる方法；溶融押出成形時に直接供給する方法などが挙げられ、いずれの方法が採用されてもよい。 As a method of containing the ultraviolet absorber, a method of blending an ultraviolet absorber in a polymer resin having an alicyclic structure in advance; a method of using a masterbatch containing a high concentration of an ultraviolet absorber; A direct supply method and the like can be mentioned, and any method may be adopted.
本発明の積層体は、中間層の両側に表面層が積層された３層積層体からなり、該中間層には紫外線吸収剤が０．５〜２．５重量％含有されてなり、かつこの中間層における紫外線吸収剤の濃度のばらつきが全面で±０．１％以内である。
紫外線吸収剤の含有量が０．５〜２．５重量％であることにより、偏光板の色調を悪化させること無く紫外線を効率的に遮断することができ、長期使用時の偏光度の低下を防ぐことができる。
中間層の紫外線吸収剤の含有量は、０．５〜２．５重量％、好ましくは１．０〜２．５重量％である。
中間層の紫外線吸収剤の含有量が０．５重量％未満であると、波長３７０ｎｍ及び３８０ｎｍにおける光線透過率が大きくなり、偏光板保護フィルムとして使用した場合に偏光子の偏光度が低下してしまう。逆に紫外線吸収剤の含有量が２．５重量％を超えると、短波長側の光線透過率が小さくなり積層体の黄色味が強くなりすぎてしまう。
中間層における紫外線吸収剤の濃度のばらつきが全面で±０．１重量％以内であることにより初期フィルムの色調ムラがなく、また、長期使用後の紫外線による劣化が均一に起こり、液晶表示装置に実装したときの色調ムラが起こりにくくなる。
中間層における紫外線吸収剤の濃度のばらつきが全面で±０．１重量％を超えると色調のムラがはっきりと視認でき、色調不良となる。また、長期使用後には紫外線による劣化が不均一となり、色調不良がさらにひどくなる。
中間層における紫外線吸収剤の濃度のばらつきは以下の手順で測定する。まず分光光度計により積層体の紫外線透過率を測定する。次に、接触式厚み計により積層体の厚さを測定する。次いで、測定部の断面を光学顕微鏡により観察し、表面層と中間層の厚さの比を求め、中間層の厚さを求める。そして、紫外線透過率と厚さから紫外線吸収剤の濃度を下記式［１］から算出する。
式［１］：Ｃ＝−ｌｏｇ（０．０１Ｔ）／Ｋ／Ｌ
式［１］において、Ｃは紫外線吸収剤の濃度（重量％）、Ｔは光線透過率（％）、Ｋは吸光係数（−）、Ｌは積層体の厚さ（μｍ）である。以上の操作を積層体の縦方向及び横方向で一定間隔毎に行い、これらの測定値の算術平均値をとりこれを平均濃度Ｃａｖｅとする。そして、測定した濃度Ｃの内最大値をＣｍａｘ、最小値をＣｍｉｎとして以下の式から算出する。
濃度のばらつき（％）＝（Ｃｍｉｎ−Ｃａｖｅ）／Ｃａｖｅ×１００、又は（Ｃｍａｘ−Ｃａｖｅ）／Ｃａｖｅ×１００
ここで前記Ｃｍｉｎ−Ｃａｖｅ、Ｃｍａｘ−Ｃａｖｅの絶対値が異なる場合は、絶対値の大きいほうをとる。
光学積層体の中間層における紫外線吸収剤の濃度のばらつきを全面で±０．１重量％とするための手段としては、（１）乾燥させた脂環式構造を有する重合体樹脂と、紫外線吸収剤とを混合させる。次いで、その混合物を押出機に接続されたホッパーへ投入し、単軸押出機へ供給して溶融押出する；（２）乾燥機付きホッパーに脂環式構造を有する重合体樹脂を投入する。また別の投入口から紫外線吸収剤を投入する。前記脂環式構造を有する重合体樹脂及び紫外線吸収剤をそれぞれフィーダーで計量しながら二軸押出機へ供給して溶融押出する方法；が挙げられる。
The laminate of the present invention comprises a three-layer laminate in which surface layers are laminated on both sides of the intermediate layer, and the intermediate layer contains 0.5 to 2.5% by weight of an ultraviolet absorber. The variation in the concentration of the UV absorber in the intermediate layer is within ± 0.1% over the entire surface.
When the content of the ultraviolet absorber is 0.5 to 2.5% by weight, it is possible to efficiently block ultraviolet rays without deteriorating the color tone of the polarizing plate, and to reduce the degree of polarization during long-term use. Can be prevented.
The content of the UV absorber in the intermediate layer is 0.5 to 2.5% by weight, preferably 1.0 to 2.5% by weight.
When the content of the UV absorber in the intermediate layer is less than 0.5% by weight, the light transmittance at wavelengths of 370 nm and 380 nm increases, and the polarization degree of the polarizer decreases when used as a polarizing plate protective film. End up. Conversely, when the content of the ultraviolet absorber exceeds 2.5% by weight, the light transmittance on the short wavelength side becomes small, and the yellowness of the laminate becomes too strong.
The dispersion of the UV absorber concentration in the intermediate layer is within ± 0.1% by weight over the entire surface, so there is no uneven color tone of the initial film, and the deterioration due to UV after long-term use occurs uniformly. Color tone unevenness when mounted is less likely to occur.
If the variation in the concentration of the UV absorber in the intermediate layer exceeds ± 0.1% by weight over the entire surface, uneven color tone can be clearly seen, resulting in poor color tone. Further, after long-term use, the deterioration due to ultraviolet rays becomes non-uniform and the color tone is further deteriorated.
The variation in the concentration of the UV absorber in the intermediate layer is measured by the following procedure. First, the ultraviolet transmittance of the laminate is measured with a spectrophotometer. Next, the thickness of the laminate is measured with a contact-type thickness meter. Next, the cross section of the measurement part is observed with an optical microscope, the ratio of the thickness of the surface layer to the intermediate layer is determined, and the thickness of the intermediate layer is determined. And the density | concentration of a ultraviolet absorber is computed from following formula [1] from a ultraviolet-ray transmittance and thickness.
Formula [1]: C = −log (0.01T) / K / L
In the formula [1], C is the concentration (% by weight) of the ultraviolet absorber, T is the light transmittance (%), K is the extinction coefficient (−), and L is the thickness (μm) of the laminate. The above operation is performed at regular intervals in the vertical and horizontal directions of the laminate, and the arithmetic average value of these measured values is taken as the average concentration C ave . Then, the maximum value of the measured concentration C is calculated as C max and the minimum value is calculated as C min from the following formula.
Variation in concentration (%) = (C min −C ave ) / C ave × 100 or (C max −C ave ) / C ave × 100
Here, when the absolute values of C min -C ave and C max -C ave are different, the larger absolute value is taken.
Means for setting the dispersion of the concentration of the ultraviolet absorber in the intermediate layer of the optical laminate to ± 0.1% by weight are as follows: (1) a polymer resin having a dried alicyclic structure, and ultraviolet absorption Mix with the agent. Next, the mixture is put into a hopper connected to an extruder, supplied to a single screw extruder and melt-extruded; (2) A polymer resin having an alicyclic structure is put into a hopper with a dryer. In addition, an ultraviolet absorber is introduced from another inlet. And a method in which the polymer resin having an alicyclic structure and the ultraviolet absorber are supplied to a twin-screw extruder while being measured with a feeder and melt-extruded.
本発明において、中間層の厚さは１０〜４０μｍであることが好ましい。中間層の厚さが１０μｍ未満であると層間の界面が荒れてしまい面状態が悪化してしまうおそれがある。一方、中間層の厚さが４０μｍを超えると偏光板保護フィルムとして使用した場合に偏光板全体が厚くなってしまい実用が難しくなる。 In the present invention, the thickness of the intermediate layer is preferably 10 to 40 μm. If the thickness of the intermediate layer is less than 10 μm, the interface between the layers may be roughened and the surface state may be deteriorated. On the other hand, when the thickness of the intermediate layer exceeds 40 μm, when used as a polarizing plate protective film, the entire polarizing plate becomes thick and practical use becomes difficult.
本発明において、中間層の厚さのばらつきが全面で±１μｍ以内であることが好ましい。中間層の厚さのばらつきが全面で±１μｍ以内であることにより、色調のばらつきが小さくなる。また、長期使用後の色調変化も均一となるため、長期使用後の色調ムラも起こらない。
中間層の厚さは、市販の接触式厚さ計を用いて、総厚を測定し、厚さ測定部分を切断し断面を光学顕微鏡で観察して、中間層と表面層との厚さ比を求めて、その比率より中間層の厚さを計算する。以上の操作を積層体の横方向及び縦方向において一定間隔毎に行う。
中間層の厚さのばらつきは、上記で測定した測定値の算術平均値を基準厚さＴａｖｅとし、測定した厚さＴの内最大値をＴｍａｘ、最小値をＴｍｉｎとして以下の式から算出する。
厚さのばらつき（μｍ）＝Ｔｍｉｎ−Ｔａｖｅ、及びＴｍａｘ−Ｔａｖｅ
ここで前記Ｔｍｉｎ−Ｔａｖｅ、及びＴｍａｘ−Ｔａｖｅの絶対値が異なる場合は、絶対値の大きいほうをとる。
本発明において、表面層には紫外線吸収剤を含有しないことが好ましく、表面層の厚さは５〜１０μｍとすることが好ましい。
In the present invention, the thickness variation of the intermediate layer is preferably within ± 1 μm on the entire surface. When the variation in the thickness of the intermediate layer is within ± 1 μm on the entire surface, the variation in color tone is reduced. In addition, since the color tone change after long-term use is uniform, color tone unevenness after long-term use does not occur.
The thickness of the intermediate layer is determined by measuring the total thickness using a commercially available contact thickness gauge, cutting the thickness measurement part and observing the cross section with an optical microscope, and the thickness ratio between the intermediate layer and the surface layer. And the thickness of the intermediate layer is calculated from the ratio. The above operation is performed at regular intervals in the horizontal and vertical directions of the laminate.
The variation in the thickness of the intermediate layer is expressed by the following equation, where the arithmetic average value of the measured values measured above is the reference thickness T ave , the maximum value of the measured thickness T is T max , and the minimum value is T min. calculate.
Thickness variation (μm) = T min −T ave and T max −T ave
Here, when the absolute values of T min -T ave and T max -T ave are different, the larger absolute value is taken.
In the present invention, the surface layer preferably contains no UV absorber, and the thickness of the surface layer is preferably 5 to 10 μm.
本発明において、積層体全体の面内位相差Ｒｅ及び厚さ方向の位相差Ｒｔｈは１０ｎｍ以下であることが好ましく、５ｎｍ以下であることがさらに好ましい。
前記Ｒｅが１０ｎｍを超えると、積層体全体の面内の遅相軸を偏光膜の透過軸または吸収軸と一致させなければならず、一致しないと光漏れが起こるおそれがある。
面内の位相差Ｒｅは、積層体の面内の主屈折率をＮｘ、Ｎｙとし、積層体の厚さをｄ（ｎｍ）とすると、Ｒｅ＝｜Ｎｘ−Ｎｙ｜×ｄで求めることができる。
厚さ方向の位相差Ｒｔｈは、積層体全体の面内の主屈折率をＮｘ、Ｎｙ、厚さ方向の屈折率をＮｚとし、積層体の厚さをｄ（ｎｍ）とすると、Ｒｔｈ＝［{（Ｎｘ＋Ｎｙ）／２}−Ｎｚ］×ｄで求めることができる。
なお、積層体の面内位相差Ｒｅ及び厚さ方向の位相差Ｒｔｈは、市販の自動複屈折計を用いて測定することができる。
In the present invention, the in-plane retardation Re and the thickness direction retardation Rth of the entire laminate are preferably 10 nm or less, and more preferably 5 nm or less.
If Re exceeds 10 nm, the in-plane slow axis of the entire laminate must be matched with the transmission axis or absorption axis of the polarizing film, otherwise light leakage may occur.
The in-plane retardation Re can be obtained by Re = | Nx−Ny | × d where Nx and Ny are the main in-plane refractive indexes of the stacked body and d (nm) is the thickness of the stacked body. .
The retardation Rth in the thickness direction is expressed as follows: Rx = [Nx, Ny for the in-plane main refractive index of the entire laminate, Nz for the refractive index in the thickness direction, and d (nm) for the thickness of the laminate. {(Nx + Ny) / 2} −Nz] × d.
The in-plane retardation Re and the thickness direction retardation Rth of the laminate can be measured using a commercially available automatic birefringence meter.
本発明においては、積層体の表面層及び中間層のどの層にも、紫外線吸収剤以外の他の配合剤を含有させてもよい。
他の配合剤としては、格別限定はないが、無機微粒子；酸化防止剤、熱安定剤、近赤外線吸収剤等の安定剤；滑剤、可塑剤等の樹脂改質剤；染料や顔料等の着色剤；帯電防止剤等が挙げられる。これらの配合剤は、単独で、あるいは２種以上を組み合せて用いることができ、その配合量は本発明の目的を損なわない範囲で適宜選択される。
In this invention, you may contain other compounding agents other than a ultraviolet absorber in any layer of the surface layer and intermediate | middle layer of a laminated body.
Other compounding agents are not particularly limited, but inorganic fine particles; stabilizers such as antioxidants, heat stabilizers and near infrared absorbers; resin modifiers such as lubricants and plasticizers; coloring dyes and pigments Agents; antistatic agents and the like. These compounding agents can be used alone or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the object of the present invention.
本発明の積層体の厚さは、３０μｍ〜１００μｍである。 The thickness of the laminated body of this invention is 30 micrometers-100 micrometers.
本発明の積層体を得る方法としては、共押出Ｔダイ法、共押出インフレーション法、共押出ラミネーション法等の共押出による成形方法、ドライラミネーション等のフィルムラミネーション成形方法、及び中間層を構成するフィルムに対して表面層を構成する樹脂溶液をコーティングするようなコーティング成形方法などの公知の方法が適宜利用され得る。中でも、製造効率や、フィルム中に溶剤などの揮発性成分を残留させないという観点から、共押出による成形方法が好ましい。
共押出する方法の中でも、共押出Ｔダイ法が好ましい。さらに共押出Ｔダイ法にはフィードブロック方式、マルチマニホールド方式が挙げられるが、中間層の厚さのばらつきを少なくできる点でマルチマニホールド方式がさらに好ましい。
As a method for obtaining the laminate of the present invention, a coextrusion T-die method, a coextrusion inflation method, a coextrusion molding method such as a coextrusion lamination method, a film lamination molding method such as dry lamination, and a film constituting an intermediate layer A known method such as a coating molding method in which a resin solution constituting the surface layer is coated can be appropriately used. Among these, a molding method by coextrusion is preferable from the viewpoints of production efficiency and that volatile components such as a solvent do not remain in the film.
Among the coextrusion methods, the coextrusion T-die method is preferable. Further, examples of the coextrusion T-die method include a feed block method and a multi-manifold method, but the multi-manifold method is more preferable in that variation in the thickness of the intermediate layer can be reduced.
積層体を得る方法として、共押出Ｔダイ法を採用する場合、Ｔダイを有する押出機における脂環式構造を有する重合体の溶融温度は、脂環式構造を有する重合体のガラス転移温度よりも８０〜１８０℃高い温度にすることが好ましく、ガラス転移温度よりも１００〜１５０℃高い温度にすることがより好ましい。押出機での溶融温度が過度に低いと脂環式構造を有する重合体の流動性が不足するおそれがあり、逆に溶融温度が過度に高いと樹脂が劣化する可能性がある。 When the coextrusion T-die method is employed as a method for obtaining a laminate, the melting temperature of the polymer having an alicyclic structure in an extruder having a T die is higher than the glass transition temperature of the polymer having an alicyclic structure. Is preferably 80 to 180 ° C., more preferably 100 to 150 ° C. higher than the glass transition temperature. If the melting temperature in the extruder is excessively low, the fluidity of the polymer having an alicyclic structure may be insufficient. Conversely, if the melting temperature is excessively high, the resin may be deteriorated.
本発明において、中間層の厚さのばらつきを全面で±１μｍ以内とするためには、（１）押出機内に目開きが２０μｍ以下のポリマーフィルターを設ける；（２）ギヤポンプを５ｒｐｍ以上で回転させる；（３）ダイス周りに囲い手段を配置する；（４）エアギャップを２００ｍｍ以下とする；（５）フィルムを冷却ロール上にキャストする際にエッジピニングを行う；（６）押出機として二軸押出機又はスクリュー形式がダブルフライト型の単軸押出機を用いる；のすべてを行う必要がある。前記（１）〜（６）の１つでも実施しないと中間層の厚さのばらつきを全面で±１μｍ以内にすることは難しい。 In the present invention, in order to keep the thickness variation of the intermediate layer within ± 1 μm, (1) a polymer filter having an opening of 20 μm or less is provided in the extruder; (2) the gear pump is rotated at 5 rpm or more. (3) Arranging means around the die; (4) Air gap is 200 mm or less; (5) Edge pinning is performed when the film is cast on a cooling roll; (6) Twin screw as an extruder Use an extruder or a single-flight extruder with a screw type double flight type. Unless even one of the above (1) to (6) is implemented, it is difficult to make the variation in the thickness of the intermediate layer within ± 1 μm on the entire surface.
押出し温度は、使用する脂環式構造を有する重合体樹脂に応じて適宜選択すればよい。押出し機内の温度で、樹脂投入口はＴｇ〜（Ｔｇ＋１００）℃、押出し機出口は（Ｔｇ＋５０）〜（Ｔｇ＋１７０）℃、ダイス温度は（Ｔｇ＋５０）℃〜（Ｔｇ＋１７０）℃とするのが好ましい。ここでＴｇは押出す樹脂のガラス転移温度である。 The extrusion temperature may be appropriately selected according to the polymer resin having an alicyclic structure to be used. The temperature inside the extruder is preferably Tg to (Tg + 100) ° C., the outlet of the extruder is (Tg + 50) to (Tg + 170) ° C., and the die temperature is preferably (Tg + 50) ° C. to (Tg + 170) ° C. Here, Tg is the glass transition temperature of the resin to be extruded.
積層体を得る方法として溶融押出法を用いる場合には、ダイスの開口部から押出されたシート状の溶融樹脂を冷却ドラムに密着させる。溶融樹脂を冷却ドラムに密着させる方法としては、特に制限されず、例えば、エアナイフ方式、バキュームボックス方式、静電密着方式などが挙げられる。
冷却ドラムの数は特に制限されないが、通常は２本以上である。また、冷却ドラムの配置方法としては、例えば、直線型、Ｚ型、Ｌ型などが挙げられるが特に制限されない。またダイスの開口部から押出された溶融樹脂の冷却ドラムへの通し方も特に制限されない。
When the melt extrusion method is used as a method for obtaining the laminate, the sheet-like molten resin extruded from the opening of the die is brought into close contact with the cooling drum. The method for bringing the molten resin into close contact with the cooling drum is not particularly limited, and examples thereof include an air knife method, a vacuum box method, and an electrostatic contact method.
The number of cooling drums is not particularly limited, but is usually two or more. Examples of the arrangement method of the cooling drum include, but are not limited to, a linear type, a Z type, and an L type. Further, the way of passing the molten resin extruded from the opening of the die through the cooling drum is not particularly limited.
本発明においては、冷却ドラムの温度により、押出されたシート状の脂環式構造を有する重合体樹脂の冷却ドラムへの密着具合が変化する。冷却ドラムの温度を上げると密着はよくなるが、温度を上げすぎるとシート状の脂環式構造を有する重合体樹脂が冷却ドラムから剥がれずに、ドラムに巻きつく不具合が発生する恐れがある。そのため、冷却ドラム温度は、好ましくはダイスから押し出す非晶性の熱可塑性樹脂のガラス転移温度をＴｇ（℃）とすると、（Ｔｇ＋３０）℃以下、さらに好ましくは（Ｔｇ−５）℃〜（Ｔｇ−４５）℃の範囲にする。そうすることにより滑りやキズなどの不具合を防止することができる。 In the present invention, the degree of adhesion of the polymer resin having an extruded sheet-like alicyclic structure to the cooling drum varies depending on the temperature of the cooling drum. When the temperature of the cooling drum is raised, the adhesion is improved. However, when the temperature is raised too much, the polymer resin having a sheet-like alicyclic structure is not peeled off from the cooling drum, and there is a possibility that a problem of winding around the drum may occur. Therefore, the cooling drum temperature is preferably (Tg + 30) ° C. or lower, more preferably (Tg−5) ° C. to (Tg−), where Tg (° C.) is the glass transition temperature of the amorphous thermoplastic resin extruded from the die. 45) Set to a range of ° C. By doing so, problems such as slipping and scratches can be prevented.
本発明の光学積層体は、液晶表示装置などの表示装置に用いられる部材、例えば、偏光板保護フィルム、位相差フィルム、輝度向上フィルム、透明導電フィルム、タッチパネル用基板、液晶基板、光拡散シート、プリズムシートなどにも用いることができる。中でも、偏光板保護フィルムに好適である。 The optical laminate of the present invention is a member used in a display device such as a liquid crystal display device, such as a polarizing plate protective film, a retardation film, a brightness enhancement film, a transparent conductive film, a touch panel substrate, a liquid crystal substrate, a light diffusion sheet, It can also be used for prism sheets and the like. Especially, it is suitable for a polarizing plate protective film.
本発明の光学積層体を偏光板保護フィルムとして用いる場合は、偏光板の片面又は両面に、適当な接着剤を介してこれを積層する。偏光板は、ポリビニルアルコール系フィルムに、ヨウ素などをドープした後、延伸加工することにより得られる。接着層としては、アクリル系重合体、シリコーン系ポリマー、ポリエステル、ポリウレタン、ポリエーテルや合成ゴムなどの適当なポリマーをベースポリマーとする粘着剤などが用いられる。 When using the optical laminated body of this invention as a polarizing plate protective film, this is laminated | stacked through the suitable adhesive agent on the single side | surface or both surfaces of a polarizing plate. The polarizing plate can be obtained by doping a polyvinyl alcohol film with iodine or the like and then stretching it. As the adhesive layer, an adhesive having a base polymer of an appropriate polymer such as acrylic polymer, silicone polymer, polyester, polyurethane, polyether or synthetic rubber is used.
本発明の光学積層体には、他の層を積層してもよい。他の層としては、反射防止層、ハードコート層、プライマー層；アンカー層；ＳｉＯｘ（x＝１．５〜２．０）超微粒子の３次元骨格からなる高均質透明多孔体層（屈折率１．２５〜１．４６）；粘着剤層；防汚層；などが挙げられる。 Other layers may be laminated on the optical laminate of the present invention. Other layers include an antireflection layer, a hard coat layer, a primer layer; an anchor layer; a highly homogeneous transparent porous layer (refractive index of 1) composed of a three-dimensional skeleton of SiOx (x = 1.5 to 2.0) ultrafine particles. 25 to 1.46); pressure-sensitive adhesive layer; antifouling layer; and the like.
本発明を、参考例、実施例及び比較例を示しながら、さらに詳細に説明するが、本発明は以下の実施例のみに限定されるものではない。
なお部及び％は特に断りのない限り重量基準である。
本実施例における評価は、以下の方法によって行った。
（１）波長３８０ｎｍ、波長３７０ｎｍ、及び波長４２０〜７８０ｎｍにおける光線透過率、並びに波長３８５〜３９５ｎｍにおける光線透過率の変化率
ＪＩＳ Ｋ０１１５（吸光光度分析通則）に準拠して、分光光度計（日本分光社製、紫外可視近赤外分光光度計「Ｖ−５７０」）を用いて測定する。
（２）中間層の紫外線吸収剤の濃度及びそのばらつき
分光光度計により紫外線領域の光線透過率を測定し、接触式厚さ計（ミツトヨ社製、ＩＤ−Ｃ１１２ＲＢ）により積層体の厚みを測定する。次いで、測定部分の断面を光学顕微鏡を用いて観察し、表面層と中間層の厚さ比を求めて中間層の厚さを求める。そして、式［１］を用いて紫外線透過率と厚さから紫外線吸収剤の濃度を算出する。以上の操作を積層体の横方向及び縦方向で行う。測定間隔は横方向及び縦方向とも２０ｍｍ間隔とする。
式［１］：Ｃ＝−ｌｏｇ（０．０１Ｔ）／Ｋ／Ｌ
式［１］において、Ｃは紫外線吸収剤の濃度（重量％）、Ｔは光線透過率（％）、Ｋは吸光係数（−）、Ｌは積層体の厚さ（μｍ）である。なお、本実施例においてＫは、波長３７０ｎｍでは０．０６、波長３８０ｎｍでは０．０４である。以上の操作を積層体の横方向及び縦方向で行い、これらの測定値の算術平均値を平均濃度Ｃａｖｅとする。そして測定した濃度Ｃの内最大値をＣｍａｘ、最小値をＣｍｉｎとして以下の式から算出する。
濃度のばらつき（％）＝（Ｃｍｉｎ−Ｃａｖｅ）／Ｃａｖｅ×１００、又は（Ｃｍａｘ−Ｃａｖｅ）／Ｃａｖｅ×１００
ここで前記Ｃｍｉｎ−Ｃａｖｅ、Ｃｍａｘ−Ｃａｖｅの絶対値が異なる場合は、絶対値の大きいほうをとる。
（３）中間層の厚さのばらつき
接触式厚さ計（ミツトヨ社製、ＩＤ−Ｃ１１２ＲＢ）を用いて、積層体の総厚を測定し、厚さ測定部分を切断し断面を光学顕微鏡で観察して、中間層と表面層との厚さ比を求めて、その比率より中間層の厚さを計算する。
測定間隔は、横方向及び縦方向とも２０ｍｍ間隔とする。
中間層の厚さのばらつきは、上記で測定した測定値の算術平均値をとりこれを基準厚さＴａｖｅとし、測定した厚さＴの内最大値をＴｍａｘ、最小値をＴｍｉｎとして以下の式から算出する。
厚さのばらつき（μｍ）＝Ｔｍｉｎ−Ｔａｖｅ、及びＴｍａｘ−Ｔａｖｅ
ここで前記Ｔｍｉｎ−Ｔａｖｅ、及びＴｍａｘ−Ｔａｖｅの絶対値が異なる場合は、絶対値の大きいほうをとる。
（４）耐久性試験
積層体を液晶表示装置（富士通社製、液晶モニターＶＬ−１５１ＶＡＷの最表面に貼付し、モニターの表示を白表示としたときの色差を輝度計（ＴＯＰＣＯＮ社製、）を用いて測定し、画面表示に色むらがないかどうか目視で確認する。
色差の測定は、紫外線を照射する前と、ＵＶランプを用いてモニターの対面から紫外線を照射しながら、温度６０℃、８０％ＲＨ環境に保持された恒温恒湿室に一週間放置した後で行う。
色差は、モニターを２０区画に分割し、それぞれのイエローインデックス（ＹＩ）の平均値とする。以上の操作を積層体２０枚について行う。
The present invention will be described in more detail with reference to reference examples, examples and comparative examples, but the present invention is not limited to the following examples.
Parts and% are based on weight unless otherwise specified.
Evaluation in this example was performed by the following method.
(1) Light transmittance at wavelengths of 380 nm, 370 nm, and 420 to 780 nm, and change rate of light transmittance at wavelengths of 385 to 395 nm, in accordance with JIS K0115 (General Absorption Spectrophotometry), spectrophotometer (JASCO) Measured by using a UV-Vis near-infrared spectrophotometer “V-570” manufactured by the company.
(2) Concentration of UV absorber in intermediate layer and variation thereof The light transmittance in the ultraviolet region is measured with a spectrophotometer, and the thickness of the laminate is measured with a contact-type thickness meter (ID-C112RB, manufactured by Mitutoyo Corporation). . Next, the cross section of the measurement part is observed using an optical microscope, the thickness ratio of the surface layer and the intermediate layer is determined, and the thickness of the intermediate layer is determined. And the density | concentration of a ultraviolet absorber is computed from a ultraviolet-ray transmittance and thickness using Formula [1]. The above operation is performed in the horizontal direction and the vertical direction of the laminate. The measurement interval is 20 mm in both the horizontal and vertical directions.
Formula [1]: C = −log (0.01T) / K / L
In the formula [1], C is the concentration (% by weight) of the ultraviolet absorber, T is the light transmittance (%), K is the extinction coefficient (−), and L is the thickness (μm) of the laminate. In this embodiment, K is 0.06 at a wavelength of 370 nm and 0.04 at a wavelength of 380 nm. The above operation is performed in the horizontal and vertical directions of the laminate, and the arithmetic average value of these measured values is defined as the average concentration C ave . Then, the maximum value of the measured concentration C is calculated as C max and the minimum value is calculated as C min from the following formula.
Variation in concentration (%) = (C min −C ave ) / C ave × 100 or (C max −C ave ) / C ave × 100
Here, when the absolute values of C min -C ave and C max -C ave are different, the larger absolute value is taken.
(3) Variation in thickness of intermediate layer Using a contact-type thickness meter (ID-C112RB, manufactured by Mitutoyo Corporation), the total thickness of the laminate is measured, the thickness measurement part is cut, and the cross section is observed with an optical microscope. Then, the thickness ratio between the intermediate layer and the surface layer is obtained, and the thickness of the intermediate layer is calculated from the ratio.
The measurement interval is 20 mm in both the horizontal and vertical directions.
The variation in the thickness of the intermediate layer is as follows: the arithmetic average value of the measured values measured above is taken as the reference thickness T ave , the maximum value of the measured thickness T is T max , and the minimum value is T min It is calculated from the formula of
Thickness variation (μm) = T min −T ave and T max −T ave
Here, when the absolute values of T min -T ave and T max -T ave are different, the larger absolute value is taken.
(4) Durability test The laminated body is attached to the liquid crystal display device (manufactured by Fujitsu Ltd., the outermost surface of the liquid crystal monitor VL-151VAW, and the color difference when the monitor display is set to white display is a luminance meter (manufactured by TOPCON). Use it to measure and visually check if the screen display is uneven.
The color difference is measured before irradiating with ultraviolet rays and after being left for one week in a constant temperature and humidity chamber maintained at 60 ° C. and 80% RH while irradiating ultraviolet rays from the opposite side of the monitor using a UV lamp. Do.
The color difference is obtained by dividing the monitor into 20 sections and calculating the average value of the yellow indexes (YI). The above operation is performed for 20 laminates.
（実施例１）
ノルボルネン系重合体（日本ゼオン社製、ＺＥＯＮＯＲ１４３０、ガラス転移温度１４０℃）を１００℃で３時間乾燥し、これと紫外線吸収剤（旭電化社製、「ＬＡ３１」、２，２´−メチレンビス（４−（１，１，３，３−テトラメチルブチル）−６−（２Ｈ−ベンゾトリアゾール−２−イル）フェノール）、融点：１９５℃）とを、前記紫外線吸収剤の濃度が１．２重量％となるように混合して混合物１を得た。
上記混合物１を目開き１０μｍのリーフディスク形状のポリマーフィルターを設置したダブルフライト型５０ｍｍ単軸押出機（スクリュー有効長さＬとスクリュー径Ｄとの比Ｌ／Ｄ＝２８）に装填されたホッパーへ投入し、押出機出口温度２６０℃、押出機のギヤポンプの回転数１２ｒｐｍで溶融樹脂をダイスリップの表面粗さＲａが０．１μｍであるマルチマニホールドダイに供給した。一方、上記ノルボルネン系重合体を目開き１０μｍのリーフディスク形状のポリマーフィルターを設置した５０ｍｍの単軸押出機（Ｌ／Ｄ＝３０）１台に導入し、押出機出口温度２６０℃、押出機のギヤポンプの回転数６ｒｐｍで溶融樹脂をダイスリップの表面粗さＲａが０．１μｍであるマルチマニホールドダイに供給した。
そして、溶融状態のノルボルネン系重合体、混合物１、及びノルボルネン系重合体それぞれをマルチマニホールドダイから２６０℃で吐出させ、１３０℃に温度調整された冷却ロールにキャストし、その後、５０℃に温度調整された冷却ロールに通して、ノルボルネン系重合体からなる層（５μｍ）−混合物１からなる層（３０μｍ）−ノルボルネン系重合体からなる層（５μｍ）の２種３層からなる幅６００ｍｍ、厚さ４０μｍの積層体１を共押出成形により得た。
なお、ダイスから吐出する際に、ダイスの両側とダイスの裏側をアルミニウム製の囲い部材で、ダイスから囲い部材までの距離を２００ｍｍ、シート状の積層体から囲い部材までの距離を２５０〜３００ｍｍの間になるように覆った。またエアギャップ量を５０ｍｍとし、溶融状態のフィルムを冷却ロールにキャストする方法としてエッジピニングを採用した。
この積層体１の両端１００ｍｍずつをトリミングして幅４００ｍｍとした。
得られた積層体１の測定結果を表１に示す。
この積層体１の耐久性試験を行った。結果を表１に示す。紫外線照射前のＹＩ値は、平均値が０．８１、最大値が０．８５、最小値が０．７８であった。紫外線照射後のＹＩ値は、平均値が０．８２、最大値が０．８９、最小値が０．７７であった。紫外線照射前後において積層体が着色しているものは１枚も無く、画面の表示の色ムラは紫外線照射前後において観察されるものはなかった。
Example 1
A norbornene-based polymer (manufactured by Nippon Zeon Co., Ltd., ZEONOR 1430, glass transition temperature 140 ° C.) is dried at 100 ° C. for 3 hours, and this and an ultraviolet absorber (Asahi Denka Co., Ltd., “LA31”, 2,2′-methylenebis (4 -(1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), melting point: 195 ° C.), the concentration of the UV absorber is 1.2% by weight The mixture 1 was obtained by mixing.
To the hopper loaded with the mixture 1 in a double flight type 50 mm single screw extruder (ratio of effective screw length L to screw diameter D L / D = 28) provided with a leaf filter-shaped polymer filter having an opening of 10 μm The molten resin was supplied to a multi-manifold die having a die slip surface roughness Ra of 0.1 μm at an extruder outlet temperature of 260 ° C. and an extruder gear pump speed of 12 rpm. On the other hand, the norbornene-based polymer was introduced into one 50 mm single-screw extruder (L / D = 30) provided with a leaf disk-shaped polymer filter having an opening of 10 μm, and the extruder outlet temperature was 260 ° C. The molten resin was supplied to a multi-manifold die having a die slip surface roughness Ra of 0.1 μm at a gear pump speed of 6 rpm.
Then, each molten norbornene polymer, mixture 1, and norbornene polymer are discharged from the multi-manifold die at 260 ° C., cast on a cooling roll adjusted to 130 ° C., and then adjusted to 50 ° C. Through a chilled roll, a layer made of norbornene-based polymer (5 μm) −a layer made of mixture 1 (30 μm) −a layer made of norbornene-based polymer (5 μm), two kinds and three layers of width 600 mm, thickness A 40 μm laminate 1 was obtained by coextrusion molding.
In addition, when discharging from the die, both sides of the die and the back side of the die are aluminum enclosure members, the distance from the die to the enclosure member is 200 mm, and the distance from the sheet-like laminate to the enclosure member is 250 to 300 mm Covered to be in between. Also, edge pinning was adopted as a method of casting the molten film to a cooling roll with an air gap amount of 50 mm.
The laminated body 1 was trimmed 100 mm at both ends to a width of 400 mm.
Table 1 shows the measurement results of the obtained laminate 1.
The durability test of this laminate 1 was performed. The results are shown in Table 1. The average YI value before ultraviolet irradiation was 0.81, the maximum value was 0.85, and the minimum value was 0.78. As for the YI value after ultraviolet irradiation, the average value was 0.82, the maximum value was 0.89, and the minimum value was 0.77. None of the laminate was colored before and after the ultraviolet irradiation, and no color unevenness in the display on the screen was observed before and after the ultraviolet irradiation.
（比較例１）
ダイスとして、Ｔ型ダイとフィードブロックダイを用い、エアギャップ量を２５０ｍｍとし、囲い部材を設けない他は、実施例１と同様にして、積層体２を得た。得られた積層体２の測定結果を表１に示す。
実施例１と同様にこの積層体２の耐久性試験を行った。紫外線照射前のＹＩ値は、平均値が０．８０、最大値が０．９５、最小値が０．６０であった。紫外線照射後のＹＩ値は、平均値が１．０１、最大値が１．５３、最小値が０．７５であった。紫外線照射前は着色しているものは一枚もなかったが、紫外線照射後は着色しているものが積層体２０枚中６枚あった。画面の表示の色ムラは、紫外線照射後において画面全体が黄色に着色され、画面全体の３割程度の部分に黄色の斑状の着色が見られた。
(Comparative Example 1)
A laminate 2 was obtained in the same manner as in Example 1 except that a T-type die and a feed block die were used as dies, the air gap amount was 250 mm, and no enclosure member was provided. Table 1 shows the measurement results of the obtained laminate 2.
The durability test of the laminate 2 was performed in the same manner as in Example 1. The average YI value before ultraviolet irradiation was 0.80, the maximum value was 0.95, and the minimum value was 0.60. As for the YI value after ultraviolet irradiation, the average value was 1.01, the maximum value was 1.53, and the minimum value was 0.75. Although none was colored before the ultraviolet irradiation, 6 of the 20 laminates were colored after the ultraviolet irradiation. As for the color unevenness of the display on the screen, the entire screen was colored yellow after ultraviolet irradiation, and yellow spots were colored in about 30% of the entire screen.
表１の結果から以下のことがわかる。
本発明によれば、実施例に示すように積層体の中間層の紫外線吸収剤の濃度のばらつきが小さく、中間層の厚さのばらつきも小さい。そのため、液晶表示装置に実装して画面を白表示にしたときのイエローインデックス及びそのばらつきが小さく、画面表示も着色していない。さらに耐久試験後においてもイエローインデックス及びそのばらつきが小さく、画面表示も着色していない。
一方、比較例では、中間層の紫外線吸収剤の濃度のばらつきや厚さのばらつきが大きい。そのため、液晶表示装置に実装して画面を白表示にしたときのイエローインデックス及びそのばらつきはそれほど大きくないが、耐久試験を行うとイエローインデックスの最大値およびイエローインデックスのばらつきも大きくなっている。また、耐久試験後において画面表示も着色しているものが見受けられる。
From the results in Table 1, the following can be understood.
According to the present invention, as shown in the examples, the variation in the concentration of the UV absorber in the intermediate layer of the laminate is small, and the variation in the thickness of the intermediate layer is also small. Therefore, the yellow index and its variation are small when mounted on a liquid crystal display device and the screen is displayed in white, and the screen display is not colored. Further, even after the durability test, the yellow index and its variation are small, and the screen display is not colored.
On the other hand, in the comparative example, there are large variations in the concentration and thickness of the UV absorber in the intermediate layer. Therefore, the yellow index and its variation when mounted on a liquid crystal display device and displaying the screen in white are not so large, but when the durability test is performed, the maximum value of the yellow index and the variation of the yellow index are also large. In addition, the screen display is also colored after the durability test.
Claims (6)
前記積層体の波長３８０ｎｍにおける光線透過率が３〜９％で、３７０ｎｍにおける光線透過率が２％以下で、波長４２０〜７８０ｎｍにおける光線透過率が８５％以上で、かつ波長３８５〜３９５ｎｍにおける光線透過率の変化率が４％／ｎｍ以上であり、
該中間層の厚さのばらつきが全面で±１μｍ以内であり、
該中間層の厚さが３０〜４０μｍであり、
該表面層の厚さが５〜１０μｍである光学積層体。
［１］中間層の紫外線吸収剤の含有量が０．５〜２．５重量％である。
［２］中間層における紫外線吸収剤の濃度のばらつきが全面で±０．１％以内である。 An optical laminate in which surface layers are laminated on both sides of an intermediate layer, wherein the resin component of each layer is a polymer resin having an alicyclic structure, and the intermediate layer comprises the following [1] and [2] Meet the requirements,
The laminate has a light transmittance of 3 to 9% at a wavelength of 380 nm, a light transmittance of 370 nm at 2% or less, a light transmittance at a wavelength of 420 to 780 nm of 85% or more, and a light transmission at a wavelength of 385 to 395 nm. der rate of change rate of 4% / nm or more is,
The thickness variation of the intermediate layer is within ± 1 μm on the entire surface,
The thickness of the intermediate layer is 30-40 μm,
Optical stack thickness Ru 5~10μm der of the surface layer.
[1] The content of the UV absorber in the intermediate layer is 0.5 to 2.5% by weight.
[2] Variation in the concentration of the UV absorber in the intermediate layer is within ± 0.1% over the entire surface.
ダイスを有する押出機の前記ダイスから前記の脂環式構造を有する重合体樹脂を共押出し、冷却ロール上にキャストする工程を有し、
（１）前記押出機内に目開きが２０μｍ以下のポリマーフィルターが設けられ、
（２）前記押出機のギヤポンプを５ｒｐｍ以上で回転させ、
（３）前記ダイス周りに囲い手段が配置され、
（４）エアギャップが２００ｍｍ以下とされ、
（５）前記冷却ロール上にキャストする際にエッジピニングを行い、
（６）前記押出機が二軸押出機又はスクリュー形式がダブルフライト型の単軸押出機である、光学積層体の製造方法。 It is a manufacturing method of the optical layered product according to any one of claims 1 to 5 ,
The polymeric resin coextrusion city from the die of an extruder having a die having an alicyclic structure described above, have a step of casting onto a chill roll,
(1) A polymer filter having an opening of 20 μm or less is provided in the extruder,
(2) The gear pump of the extruder is rotated at 5 rpm or more,
(3) An enclosure means is disposed around the die,
(4) The air gap is 200 mm or less,
(5) Perform edge pinning when casting on the cooling roll,
(6) The method for producing an optical laminate , wherein the extruder is a twin-screw extruder or a screw type double-flight type single-screw extruder .
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20160114588A (en) | 2014-01-30 | 2016-10-05 | 니폰 제온 가부시키가이샤 | Laminate and polarizing plate |
| KR20170128266A (en) | 2015-03-16 | 2017-11-22 | 니폰 제온 가부시키가이샤 | Optical laminate, polarizing plate and liquid crystal display |
| KR20180097590A (en) | 2015-12-28 | 2018-08-31 | 니폰 제온 가부시키가이샤 | Optical laminate, polarizing plate and liquid crystal display |
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| JP2005181615A (en) | 2005-07-07 |
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