JP7447055B2 - Polyvinyl alcohol film and optical film using it - Google Patents
Polyvinyl alcohol film and optical film using it Download PDFInfo
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- 239000010408 film Substances 0.000 title claims description 139
- 229920002451 polyvinyl alcohol Polymers 0.000 title claims description 131
- 239000004372 Polyvinyl alcohol Substances 0.000 title claims description 130
- 239000012788 optical film Substances 0.000 title claims description 16
- 239000013078 crystal Substances 0.000 claims description 8
- 230000010287 polarization Effects 0.000 claims description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims 1
- 229920002554 vinyl polymer Polymers 0.000 claims 1
- 238000005266 casting Methods 0.000 description 27
- 239000000243 solution Substances 0.000 description 22
- 238000004519 manufacturing process Methods 0.000 description 20
- 229920005989 resin Polymers 0.000 description 17
- 239000011347 resin Substances 0.000 description 17
- 238000001035 drying Methods 0.000 description 12
- 238000000034 method Methods 0.000 description 12
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 9
- 238000009826 distribution Methods 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 6
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 5
- 239000004327 boric acid Substances 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000004043 dyeing Methods 0.000 description 5
- 239000004014 plasticizer Substances 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 229920001567 vinyl ester resin Polymers 0.000 description 4
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 3
- 238000007667 floating Methods 0.000 description 3
- 239000000499 gel Substances 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- -1 olefin compound Chemical class 0.000 description 3
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- 239000006057 Non-nutritive feed additive Substances 0.000 description 2
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000007127 saponification reaction Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- MEGHWIAOTJPCHQ-UHFFFAOYSA-N ethenyl butanoate Chemical compound CCCC(=O)OC=C MEGHWIAOTJPCHQ-UHFFFAOYSA-N 0.000 description 1
- GFJVXXWOPWLRNU-UHFFFAOYSA-N ethenyl formate Chemical compound C=COC=O GFJVXXWOPWLRNU-UHFFFAOYSA-N 0.000 description 1
- QBDADGJLZNIRFQ-UHFFFAOYSA-N ethenyl octanoate Chemical compound CCCCCCCC(=O)OC=C QBDADGJLZNIRFQ-UHFFFAOYSA-N 0.000 description 1
- BLZSRIYYOIZLJL-UHFFFAOYSA-N ethenyl pentanoate Chemical compound CCCCC(=O)OC=C BLZSRIYYOIZLJL-UHFFFAOYSA-N 0.000 description 1
- UIWXSTHGICQLQT-UHFFFAOYSA-N ethenyl propanoate Chemical compound CCC(=O)OC=C UIWXSTHGICQLQT-UHFFFAOYSA-N 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 229920001477 hydrophilic polymer Polymers 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 239000011630 iodine Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229920001290 polyvinyl ester Polymers 0.000 description 1
- LYBIZMNPXTXVMV-UHFFFAOYSA-N propan-2-yl prop-2-enoate Chemical compound CC(C)OC(=O)C=C LYBIZMNPXTXVMV-UHFFFAOYSA-N 0.000 description 1
- PNXMTCDJUBJHQJ-UHFFFAOYSA-N propyl prop-2-enoate Chemical compound CCCOC(=O)C=C PNXMTCDJUBJHQJ-UHFFFAOYSA-N 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- UWHCKJMYHZGTIT-UHFFFAOYSA-N tetraethylene glycol Chemical compound OCCOCCOCCOCCO UWHCKJMYHZGTIT-UHFFFAOYSA-N 0.000 description 1
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 description 1
- 229910021642 ultra pure water Inorganic materials 0.000 description 1
- 239000012498 ultrapure water Substances 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2329/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
- C08J2329/02—Homopolymers or copolymers of unsaturated alcohols
- C08J2329/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
Landscapes
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Polarising Elements (AREA)
Description
本発明は、光学フィルムとして、特に偏光フィルムとして用いることができ、様々な分野に応用され、特にディスプレイ装置に応用される、ポリビニルアルコール（ｐｏｌｙｖｉｎｙｌ ａｌｃｏｈｏｌ，ＰＶＡ）フィルムに関するものである。 The present invention relates to a polyvinyl alcohol (PVA) film that can be used as an optical film, especially as a polarizing film, and is applied in various fields, especially in display devices.
ポリビニルアルコール（ｐｏｌｙｖｉｎｙｌ ａｌｃｏｈｏｌ，ＰＶＡ）フィルムは一種の親水性ポリマーであり、透明性、機械的強度、水溶性、良好な加工性などの性能を有し、包装材料又は電子製品の光学フィルムにおいて、特に偏光フィルムにおいて広く用いられている。 Polyvinyl alcohol (PVA) film is a kind of hydrophilic polymer, which has properties such as transparency, mechanical strength, water solubility, and good processability, and is especially used in packaging materials or optical films for electronic products. Widely used in polarizing films.
ＰＶＡフィルムで光学フィルムを調製する製造工程では、必要とする性能に従い選択的に官能基修飾を使用することができ、その後で延伸が行われる。製造方法は乾式と湿式に大別することができ、乾式は、一定の温湿度下において、不活性ガス雰囲気下でＰＶＡフィルムの延伸を行ってから、染色などの工程を行うものである。湿式は、ＰＶＡフィルムの染色を行ってから、溶液中で延伸を行うものである。乾式で調製されたＰＶＡフィルムは、表面に平坦性がないか又は染色が不均一になるという問題がしばしば起こるが、湿式で製造されたＰＶＡフィルムは良好な性能（例えば色が均一）を具備するため、現在では一般的に湿式法を用いてＰＶＡフィルムを製造することが多い。 In the manufacturing process for preparing optical films with PVA films, functional group modifications can be selectively used according to the required performance, followed by stretching. Manufacturing methods can be roughly divided into dry and wet methods. The dry method involves stretching the PVA film in an inert gas atmosphere at a constant temperature and humidity, and then performing steps such as dyeing. The wet method involves dyeing the PVA film and then stretching it in a solution. Dry-prepared PVA films often have problems with uneven surfaces or uneven dyeing, whereas wet-processed PVA films have good performance (e.g., uniform color). Therefore, at present, PVA films are generally manufactured using a wet method.
偏光フィルムを製造する場合には、延伸倍率が高くなるほど、得られる光学性能も高くなるため、延伸時にはＰＶＡフィルムが断裂に近づく臨界近傍まで可能な限り延伸し、光学特性に優れたＰＶＡフィルムを得る。 When producing a polarizing film, the higher the stretching ratio, the higher the optical performance obtained. Therefore, during stretching, the PVA film is stretched as much as possible to near the critical point where it approaches rupture to obtain a PVA film with excellent optical properties. .
しかし、修飾又は染色を行うと、ＰＶＡフィルムの延伸性及び耐え得る引張強度が変化し、ＰＶＡフィルムの延伸が不均一な場合にはフィルム切れが発生してしまう。そのため、如何に均一な延伸が可能なＰＶＡフィルムを製造し、フィルム切れ現象を低減させるかが、現在のＰＶＡフィルムにおいて開発を要する目標の１つとなっている。 However, modification or dyeing changes the stretchability and tensile strength of the PVA film, and when the PVA film is stretched unevenly, film breakage occurs. Therefore, one of the goals that needs to be developed in current PVA films is how to produce a PVA film that can be stretched uniformly and how to reduce the phenomenon of film breakage.
本発明は、有する遅延量（retardation）の標準偏差が＜３ｎｍであり、且つ遅延量のフィッティングパラメータが│Ａｓｙｍ５０－１│＊１０8＜１０である、ＰＶＡフィルムを提供することを目的としている。 The present invention aims to provide a PVA film having a standard deviation of retardation of <3 nm and a fitting parameter of the retardation of |Asym50-1|*10 8 <10.
好ましい実施例中、ＰＶＡフィルムが有する最大遅延量は＜５６ｎｍである。 In a preferred embodiment, the maximum amount of retardation that the PVA film has is <56 nm.
好ましい実施例中、ＰＶＡフィルムのＭＤ方向の破断伸び率は＞４００％である。 In a preferred embodiment, the elongation at break of the PVA film in the MD direction is >400%.
好ましい実施例中、ＰＶＡフィルムの含水率は＞２．０ｗｔ％である。 In a preferred embodiment, the moisture content of the PVA film is >2.0 wt%.
好ましい実施例中、ＰＶＡフィルムのｐＨ値５．５～８．５の間である。 In a preferred embodiment, the pH value of the PVA film is between 5.5 and 8.5.
好ましい実施例中、ＰＶＡフィルムの結晶面の粒子サイズは４～６ｎｍである。 In a preferred embodiment, the grain size of the crystal plane of the PVA film is 4-6 nm.
本発明の別の目的は、光学フィルムを提供することであり、それは本発明のＰＶＡフィルムで製造されたものである。 Another object of the present invention is to provide an optical film, which is made with the PVA film of the present invention.
好ましい実施例中、光学フィルムは偏光フィルムである。 In preferred embodiments, the optical film is a polarizing film.
好ましい実施例中、偏光フィルムが有する偏光度は＞９９．８である。 In a preferred embodiment, the polarizing film has a degree of polarization >99.8.
公知技術と比べて、本発明のＰＶＡフィルムは均一で対称な遅延量を有しており、後の光学フィルム調製に用いた場合、均一に延伸することができてフィルム切れが発生しにくく、偏光フィルムを製造する際の欠点が効果的に改善され、製造での歩留まり率が向上する。 Compared with the known technology, the PVA film of the present invention has a uniform and symmetrical retardation amount, and when used for later optical film preparation, it can be stretched uniformly, less likely to break the film, and is less likely to cause polarized light. The defects in film production are effectively improved, and the yield rate in production is improved.
以下の実施形態は、本発明を過度に限定するものではない。本発明が属する技術分野の当業者は、本発明の精神又は範囲から逸脱せずに本明細書中で検討する実施例に対して修正や変更を行うことができ、いずれも本発明の範囲に即する。 The following embodiments are not intended to unduly limit the invention. Those skilled in the art to which this invention pertains will be able to make modifications and changes to the embodiments discussed herein without departing from the spirit or scope of the invention; Immediately.
本明細書中の「１」及び「一種」という用語は、本明細書において文法の対象が１つ以上（即ち少なくとも１つ）存在することを指す。 The terms "1" and "kind" as used herein refer to the presence of one or more (ie, at least one) grammatical object.
本発明のポリビニルアルコール（ｐｏｌｙｖｉｎｙｌ ａｌｃｏｈｏｌ，ＰＶＡ）フィルムは、有する遅延量の標準偏差が＜３ｎｍであり、且つ遅延量のフィッティングパラメータは│Ａｓｙｍ５０－１│＊１０8＜１０である。本発明のＰＶＡフィルムの製造方法は、ポリビニルアルコール鋳造溶液を調製した後、ポリビニルアルコール鋳造溶液を鋳造ドラムに鋳込み、乾燥を経てポリビニルアルコール系ポリマーフィルムを形成する、という工程を含む。 The polyvinyl alcohol (PVA) film of the present invention has a standard deviation of retardation of <3 nm, and a fitting parameter of retardation of |Asym50-1|*10 8 <10. The method for producing a PVA film of the present invention includes the steps of preparing a polyvinyl alcohol casting solution, then casting the polyvinyl alcohol casting solution into a casting drum, and forming a polyvinyl alcohol polymer film through drying.
具体的に、ＰＶＡフィルムの製造方法は以下の工程を含む。溶解タンク中、ポリビニルアルコール樹脂を溶液（例えば水）中に溶解してポリビニルアルコール鋳造溶液を形成する。選択的にフィルタでポリビニルアルコール鋳造溶液を濾過してもよい。その後、歯車ポンプ（ｇｅａｒ ｐｕｍｐ）及びコーティング機（例えばＴ型ダイコーター）を用いてポリビニルアルコール鋳造溶液を鋳造ドラムに鋳込む。最後に、ドラムに成膜されたＰＶＡフィルムを剥離した後、一連の加熱ローラ及び／又は乾燥の熱処理を経てＰＶＡフィルムを得る。 Specifically, the method for manufacturing a PVA film includes the following steps. In a dissolution tank, polyvinyl alcohol resin is dissolved in a solution (eg, water) to form a polyvinyl alcohol casting solution. The polyvinyl alcohol casting solution may optionally be filtered with a filter. The polyvinyl alcohol casting solution is then cast into the casting drum using a gear pump and a coating machine (eg, a T-die coater). Finally, after peeling off the PVA film formed on the drum, a PVA film is obtained through a series of heating roller and/or drying heat treatments.
ポリビニルアルコール鋳造溶液の調製では、ポリビニルアルコール樹脂を溶解タンク中で溶解するが、溶解タンク中の溶解温度は＞１００℃であり、好適には＞１１０℃、より好適には＞１２０℃であり、具体的には、例えば１０５℃、１１０℃、１１５℃、１２０℃、１２５℃、１３０℃、１３５℃又は１４０℃であるが、本発明はこれらに限定されない。溶解タンクは毎時４～２０℃の速度で昇温するのが好ましく、好適には５～１５℃、より好適には６～９℃であり、具体的には、例えば４．０℃／ｈｒ、５．０℃／ｈｒ、６．０℃／ｈｒ、７．０℃／ｈｒ、８．０℃／ｈｒ、９．０℃／ｈｒ、１０℃／ｈｒ、１１℃／ｈｒ、１２℃／ｈｒ、１３℃／ｈｒ、１４℃／ｈｒ、１５℃／ｈｒ、１６℃／ｈｒ、１７℃／ｈｒ、１８℃／ｈｒ、１９℃／ｈｒ又は２０℃／ｈｒなどであり、昇温速度が速すぎると、ポリビニルアルコール樹脂にケーキングが発生しやすくなり、溶解が不完全になってしまう。所望の溶解温度まで昇温させた後、ポリビニルアルコール鋳造溶液を２～４時間攪拌し続けるが、好適には３時間であり、且つ１時間に少なくとも２回攪拌方向を変えるが、好適には３回であり、例えば時計回りに２０分間回転させた後、反時計回りに２０分間回転させる。上述の攪拌過程における方向の反転は溶解効果を高め、ポリビニルアルコール鋳造溶液中にクラスター（ｃｌｕｓｔｅｒ）が残ってしまうのを防ぐことができる。 In preparing the polyvinyl alcohol casting solution, the polyvinyl alcohol resin is melted in a melting tank, the melting temperature in the melting tank being >100°C, preferably >110°C, more preferably >120°C; Specifically, the temperature is, for example, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C, but the present invention is not limited thereto. The temperature of the dissolution tank is preferably increased at a rate of 4 to 20°C per hour, preferably 5 to 15°C, more preferably 6 to 9°C, and specifically, for example, 4.0°C/hr. 5.0°C/hr, 6.0°C/hr, 7.0°C/hr, 8.0°C/hr, 9.0°C/hr, 10°C/hr, 11°C/hr, 12°C/hr, 13°C/hr, 14°C/hr, 15°C/hr, 16°C/hr, 17°C/hr, 18°C/hr, 19°C/hr or 20°C/hr, etc. If the temperature increase rate is too fast , caking tends to occur in the polyvinyl alcohol resin, resulting in incomplete dissolution. After heating to the desired melting temperature, the polyvinyl alcohol casting solution is continued to be stirred for 2 to 4 hours, preferably 3 hours, and the stirring direction is changed at least twice per hour, but preferably 3 hours. For example, after rotating clockwise for 20 minutes, it is rotated counterclockwise for 20 minutes. The above-mentioned reversal of direction during the stirring process can enhance the dissolution effect and prevent clusters from remaining in the polyvinyl alcohol casting solution.
ポリビニルアルコール鋳造溶液の調製では、ポリビニルアルコール樹脂の含有量は１０～６０ｗｔ％であり、好適には１５～４０ｗｔ％、より好適には２０～３０ｗｔ％であり、具体的には、例えば１０、１５、２０、２５、３０、３５、４０、４５、５０、５５、６０ｗｔ％などである。ポリビニルアルコール樹脂の含有量が不足すると、ポリビニルアルコール鋳造溶液の粘度が低くなりすぎて、乾燥負荷が過度に大きくなり、ＰＶＡフィルム調製における成膜効率が悪くなってしまう。反対に、ポリビニルアルコール樹脂の含有量が高すぎると、ポリビニルアルコール樹脂が溶解しにくくなって、クラスターが残りやすくなり、ＰＶＡフィルムの位相差の均一性が劣化し、後続の製造プロセスにおけるフィルムの延伸均一性に影響を及ぼし、さらには延伸時に切れる可能性にも影響が及んでしまう。 In preparing the polyvinyl alcohol casting solution, the content of polyvinyl alcohol resin is 10 to 60 wt%, preferably 15 to 40 wt%, more preferably 20 to 30 wt%, specifically, for example 10, 15 wt%. , 20, 25, 30, 35, 40, 45, 50, 55, 60 wt%, etc. If the content of the polyvinyl alcohol resin is insufficient, the viscosity of the polyvinyl alcohol casting solution will become too low, the drying load will become excessively large, and the film forming efficiency in PVA film preparation will deteriorate. On the other hand, if the content of polyvinyl alcohol resin is too high, the polyvinyl alcohol resin will be difficult to dissolve and clusters will remain easily, which will deteriorate the uniformity of the retardation of the PVA film and reduce the stretching of the film in the subsequent manufacturing process. This affects the uniformity and even the possibility of breaking during stretching.
上述のポリビニルアルコール樹脂は、ビニルエステル系樹脂単量体の重合によりポリビニルエステル系樹脂を形成した後、鹸化反応を行って得たものである。そのうち、ビニルエステル系樹脂単量体は、ギ酸ビニル、酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、ペンタン酸ビニル、オクタン酸ビニルなどのビニルエステル類を含むが、本発明はこれらに限定されず、好適には酢酸ビニルである。また、オレフィン類化合物又はアクリレート誘導体と上述のビニルエステル系樹脂単量体との共重合体も使用可能である。オレフィン類化合物は、エチレン、プロピレン又はブチレンなどを含むが、本発明はこれらに限定されない。アクリレート誘導体はアクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ－プロピル、アクリル酸イソプロピル又はアクリル酸ｎ－ブチルなどを含むが、本発明はこれらに限定されない。 The above-mentioned polyvinyl alcohol resin is obtained by forming a polyvinyl ester resin by polymerizing vinyl ester resin monomers and then performing a saponification reaction. Among them, vinyl ester resin monomers include vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pentanoate, and vinyl octanoate, but the present invention is not limited to these and is suitable. is vinyl acetate. Moreover, a copolymer of an olefin compound or an acrylate derivative and the above-mentioned vinyl ester resin monomer can also be used. The olefin compounds include ethylene, propylene, butylene, etc., but the present invention is not limited thereto. Acrylate derivatives include, but are not limited to, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, or n-butyl acrylate.
ポリビニルアルコール樹脂の鹸化度は９０％以上であり、好適には９９％以上であり、これにより良好な光学特性が得られるが、具体的には、例えば９０、９１、９２、９３、９４、９５、９６、９７、９８、９９、９９．１、９９．２、９９．３、９９．４、９９．５、９９．６、９９．７、９９．８、９９．９％などである。ポリビニルアルコールの重合度は８００～１００００の間であり、好適には２２００～１００００の間であり、具体的には、例えば８００、９００、１０００、２０００、３０００、４０００、５０００、６０００、７０００、８０００、９０００、１００００などであり、重合度が８００を上回ると良好な加工特性を具備するが、重合度が１００００を上回ると溶解するのに都合が悪くなる。 The degree of saponification of the polyvinyl alcohol resin is 90% or more, preferably 99% or more, which provides good optical properties. Specifically, for example, 90, 91, 92, 93, 94, 95 , 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9%, etc. The degree of polymerization of polyvinyl alcohol is between 800 and 10,000, preferably between 2,200 and 10,000, specifically, for example, 800, 900, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000. .
鋳造溶液中には、ポリビニルアルコール系樹脂のほかに、可塑剤を含めて成膜の加工性を増強することもでき、使用可能な可塑剤には、例えばエチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、プロピレングリコール又はグリセロールなどの多価アルコールが含まれるが、本発明はこれらに限定されず、好適にはエチレングリコール及びグリセロールである。可塑剤の添加量は通常、ポリビニルアルコール樹脂１００重量部に対して３～３０重量部の間であり、好適には７～２０重量部の間であり、具体的には、例えば３、４、５、６、７、８、９、１０、１１、１２、１３、１４、１５、１６、１７、１８、１９、２０、２１、２２、２３、２４、２５、２６、２７、２８、２９、３０重量部などである。可塑剤の含有量が不足すると、形成されるＰＶＡフィルムに結晶が生じやすくなり、後続の加工における染色効果に影響を及ぼしてしまう。反対に、可塑剤の含有量が高すぎると、ＰＶＡフィルムの機械的性質が損なわれてしまう。 In addition to the polyvinyl alcohol resin, the casting solution can also contain a plasticizer to enhance the processability of film formation. Examples of plasticizers that can be used include ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol. Polyhydric alcohols include, but are not limited to, ethylene glycol, propylene glycol or glycerol, with ethylene glycol and glycerol being preferred. The amount of plasticizer added is usually between 3 and 30 parts by weight, preferably between 7 and 20 parts by weight, based on 100 parts by weight of the polyvinyl alcohol resin. 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, For example, 30 parts by weight. If the content of plasticizer is insufficient, crystals are likely to form in the formed PVA film, which will affect the dyeing effect in subsequent processing. On the contrary, if the content of plasticizer is too high, the mechanical properties of the PVA film will be impaired.
ＰＶＡフィルムの製造方法において使用する設備には、溶解タンク、フィルタ、コーティング機及び溶解タンクからコーティング機の前まで接続される輸送配管が含まれ、好ましい状態としては、それら設備に保温装置が被覆されており、保温装置は金属発熱体（電熱線）、又は内部に油や水などの液体が入れられたジャケットでよく、金属ワイヤ又はジャケット内の液体を加熱し、それら設備（特に設備と配管の表面）を均一に加熱して保温状態を維持させることで、設備又は配管の表面温度が失われてポリビニルアルコール鋳造溶液中のポリビニルアルコールにゲルやクラスターが形成されるのを防止する。また、保温温度は過度に高くしてはならず、さもないとポリビニルアルコール鋳造溶液の一部が脱水又はゲル化し、キツネ色又は黒色のゲルが形成され、後工程における塗布成膜後のＰＶＡフィルムの表面品質や均一性に影響を及ぼしてしまう。塗布成形におけるポリビニルアルコール鋳造溶液の保温温度は８０～１２０℃であり、好適には９０～１１０℃、より好適には９０～１００℃であり、具体的には、例えば８０、８５、９０、９５、１００、１０５、１１０、１１５、１２０℃などである。 The equipment used in the PVA film manufacturing method includes a dissolution tank, a filter, a coating machine, and a transport pipe connected from the dissolution tank to the front of the coating machine, and preferably these facilities are covered with a heat insulating device. The heat insulating device may be a metal heating element (heating wire) or a jacket containing a liquid such as oil or water. By uniformly heating the surface (surface) and maintaining a warm state, it is possible to prevent the surface temperature of the equipment or piping from being lost and forming gels or clusters in the polyvinyl alcohol in the polyvinyl alcohol casting solution. In addition, the insulating temperature should not be too high, otherwise a part of the polyvinyl alcohol casting solution will dehydrate or gel, forming a golden brown or black gel, and the PVA film after coating in the subsequent process. surface quality and uniformity. The heat retention temperature of the polyvinyl alcohol casting solution in coating molding is 80 to 120°C, preferably 90 to 110°C, more preferably 90 to 100°C, and specifically, for example, 80, 85, 90, 95 , 100, 105, 110, 115, 120°C, etc.
ポリビニルアルコール鋳造溶液を鋳造ドラムに鋳込むとき、鋳造ドラムの回転速度は約３～７ｍ／ｍｉｎであり、好適には４～６ｍ／ｍｉｎである。ドラムの速度が遅すぎると、鋳造溶液が過度に乾燥し、位相差、融点分布が不均一になる傾向がある。反対に、ドラムの速度が速すぎると、鋳造溶液の乾燥が不十分となり、剥離性が低下してしまう。また、好ましい実施形態中、ドラムの温度は８５～９０℃に設定し、具体的には、例えば８５、８６、８８、８７、８８、８９、９０℃などであり、ドラムの温度が高すぎると、ドラム上の鋳造溶液に起泡現象が生じやすくなる。 When casting the polyvinyl alcohol casting solution into the casting drum, the rotational speed of the casting drum is about 3-7 m/min, preferably 4-6 m/min. If the drum speed is too slow, the casting solution tends to be excessively dry, resulting in uneven phase difference and melting point distribution. On the other hand, if the speed of the drum is too high, the casting solution will not be sufficiently dried and the releasability will be reduced. In a preferred embodiment, the temperature of the drum is set at 85 to 90°C, specifically, for example, 85, 86, 88, 87, 88, 89, 90°C, etc., and if the drum temperature is too high, , the casting solution on the drum is likely to cause foaming phenomenon.
鋳造ドラム上で最初に成膜したＰＶＡフィルムをドラムから剥離した後、乾燥を経てＰＶＡフィルムが形成されるが、乾燥過程は、加熱ローラ上で行うか、又はフローティングドライヤー上で行うか、選択することができる。加熱ローラ及びフローティングドライヤーの数は特に限定されず、必要に応じて調整できる。但し、好ましい実施例中、乾燥室（即ち乾燥器）の温度比は最高／最低が２．０～２．４である。乾燥室の温度比が大きすぎると、結晶化度が不均一になりやすく、ＰＶＡフィルムを光学フィルムの製造に使用する際にホウ酸との反応が不均一になってしまう。また、隣接する乾燥室の温度差は６５℃以下であるのが好ましく、より好適には６０℃以下であり、最適なのは５０℃であり、隣接する乾燥室の温度差が大きすぎると、位相差の分布が不均一になりやすくなる。また、フローティングドライヤー内で幅方向（即ち機械方向に垂直）に沿って成形されたＰＶＡフィルムが受ける空気流量は特に限定されないが、最大／最小の空気流量比は３．０以下に制御しなければならず、具体的には、例えば０、０．５、１．０、１．５、２．０、２．５又は３．０である。風量が多い場所は水分が奪われやすいため、乾燥度が高くなるが、この空気流量比範囲であれば、ＰＶＡフィルムの各位置が触れる風量を同一に制御して均一に乾燥させることが可能である。また、空気流量比が大きすぎると、ＰＶＡフィルムを光学フィルムの製造に使用する際に、ホウ酸との反応が不均一になったり位相差が不均一になったりする問題が生じてしまう。 After the PVA film that is first formed on the casting drum is peeled off from the drum, it is dried to form a PVA film.The drying process can be performed on a heated roller or on a floating dryer. be able to. The number of heating rollers and floating dryers is not particularly limited and can be adjusted as necessary. However, in a preferred embodiment, the maximum/minimum temperature ratio of the drying chamber (ie, dryer) is 2.0 to 2.4. If the temperature ratio of the drying chamber is too large, the degree of crystallinity tends to become non-uniform, and the reaction with boric acid becomes non-uniform when the PVA film is used to produce an optical film. In addition, the temperature difference between adjacent drying chambers is preferably 65°C or less, more preferably 60°C or less, and optimally 50°C. If the temperature difference between adjacent drying chambers is too large, the phase difference distribution tends to become uneven. Furthermore, the air flow rate that the PVA film that is formed along the width direction (i.e., perpendicular to the machine direction) receives in the floating dryer is not particularly limited, but the maximum/minimum air flow ratio must be controlled to 3.0 or less. Specifically, it is, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0. Areas with a large amount of airflow tend to absorb moisture, resulting in higher dryness, but within this airflow ratio range, it is possible to control the amount of air that touches each position of the PVA film at the same rate and dry it evenly. be. Furthermore, if the air flow rate ratio is too large, problems such as non-uniform reaction with boric acid and non-uniform retardation occur when the PVA film is used for manufacturing optical films.
本発明中、ＭＤは機械方向（Ｍａｃｈｉｎｅ Ｄｉｒｅｃｔｉｏｎ）、即ちＰＶＡフィルムの縦方向であり、ＴＤは幅方向（Ｔｒａｎｓｖｅｒｓｅ Ｄｉｒｅｃｔｉｏｎ）、即ちＰＶＡフィルムの横方向である。 In the present invention, MD is the machine direction, that is, the longitudinal direction of the PVA film, and TD is the transverse direction, that is, the transverse direction of the PVA film.
本発明中、遅延量（Ｒｅｔａｒｄａｔｉｏｎ）とは、光がフィルムを通過するときの入射偏光の位相変化量であり、即ち位相が遅延した量のことをいい、単位はｎｍである。遅延量数値の均一性は分子の配向均一性及び厚み均一性に関わり、後続の光学フィルムの製造工程に大きく影響する。図１に示す通り、遅延量の測定では、ホウ酸処理後のＰＶＡフィルムのうちのＭＤ位置を、ＴＤ方向で端部から４０ｃｍ以内の範囲内とし、ＴＤ方向に沿って左、中、右で１０ｃｍ＊１０ｃｍの面積の試験片を３枚切り出して測定を行い、範囲内の全てのポイントにおける遅延量数値及び統計データ（最大値、標準偏差など）を得ることができる。 In the present invention, the amount of retardation (Retardation) refers to the amount of phase change of incident polarized light when light passes through a film, that is, the amount by which the phase is delayed, and the unit is nm. The uniformity of the delay amount value is related to the uniformity of molecular orientation and uniformity of thickness, and greatly affects the subsequent manufacturing process of the optical film. As shown in Figure 1, in the measurement of the amount of delay, the MD position of the PVA film after boric acid treatment was within 40 cm from the end in the TD direction, and the MD position was set at the left, middle, and right along the TD direction. Three test pieces with an area of 10 cm * 10 cm are cut out and measured, and the delay amount values and statistical data (maximum value, standard deviation, etc.) at all points within the range can be obtained.
本発明中、上述の遅延量のフィッティングパラメータ│Ａｓｙｍ５０－１│＊１０8は、ＰＶＡフィルムで測定された遅延量の数値をフィッティングして得たパラメータである。フィッティングは遅延量の数値を分布図で表すものであり、表１に示す通り、遅延量の数値区間における中央値はＸ軸データ、曲線下面積（ａｒｅａ）はＹ軸として作図し、その分布図は対称分布に近くなる。ガウス－ローレンツ（Ｇａｕｓｓｉａｎ－Ｌｏｒｅｎｔｚｉａｎ Ｓｕｍ）対称関数を用いてフィッティングを行い、且つソフトウェアのＰｅａｋＦｉｔを用いてデータのフィッティングを行う。フィッティングの範囲には主要分布区間を選択し、２つの端点Ｙ値が０のデータを含め、それ以外のデータは除去し、フィッティング時にはピーク幅と形状が自由に変動できるようにして、最良のフィッティング結果を得る。高速フィッティング（Ｆａｓｔ Ｐｅａｋ Ｆｉｔ ｗｉｔｈ Ｎｕｍｅｒｉｃａｌ Ｕｐｄａｔｅ）を行い、反復値（Ｉｔｅｒａｔｉｏｎ ｖａｌｕｅ）が変化しなくなるまで繰り返し、Ａｓｙｍ５０の数値を記録する。フィッティング後の対称分布図は図２に示す通りであり、黒い点は遅延量の分布、曲線はガウス－ローレンツ（Ｇａｕｓｓｉａｎ－Ｌｏｒｅｎｔｚｉａｎ Ｓｕｍ）対称関数のフィッティングデータである。 In the present invention, the above-mentioned delay amount fitting parameter |Asym50-1|*10 8 is a parameter obtained by fitting the delay amount values measured with the PVA film. Fitting is to represent the numerical value of the delay amount in a distribution diagram.As shown in Table 1, the median value in the numerical interval of the delay amount is plotted as the X-axis data, the area under the curve (area) is plotted as the Y-axis, and the distribution diagram is plotted. is close to a symmetric distribution. Fitting is performed using a Gaussian-Lorentzian Sum symmetry function and data fitting is performed using the software PeakFit. Select the main distribution interval for the fitting range, include data with two endpoint Y values of 0, remove other data, and allow the peak width and shape to vary freely during fitting to obtain the best fit. Get results. Perform fast fitting (Fast Peak Fit with Numerical Update), repeat until the iteration value does not change, and record the numerical value of Asym50. The symmetric distribution diagram after fitting is as shown in FIG. 2, where the black dots are the delay amount distribution and the curves are the fitting data of the Gaussian-Lorentzian Sum symmetric function.
本発明のＰＶＡフィルムは有する遅延量の標準偏差が＜３ｎｍであり、且つ遅延量のフィッティングパラメータは│Ａｓｙｍ５０－１│＊１０8＜１０である。具体的には、遅延量の標準偏差は例えば０．５ｎｍ、１ｎｍ、１．５ｎｍ、２ｎｍ、２．５ｎｍ又は２．９ｎｍであるが、本発明はこれらに限定されない。遅延量のフィッティングパラメータ│Ａｓｙｍ５０－１│＊１０8は例えば０、１、２、３、４、５、６、７、８又は９であるが、本発明はこれらに限定されず、好適には０である。遅延量の標準偏差が＜３ｎｍ且つフィッティングパラメータが│Ａｓｙｍ５０－１│＊１０8＜１０である場合、ＰＶＡフィルムは均一な遅延量を有し、後の光学フィルム調製での延伸時において良好な均一性を有し、フィルムが断裂しにくくなる。これは、ＰＶＡフィルムの遅延量が複屈折値及びフィルム厚さの影響を受けることが原因であり、複屈折値はポリビニルアルコールの分子配向が大きくなるほど数値も大きくなり、フィルム厚さが厚いほど光路が長くなり、測定される遅延量も大きくなる。 The PVA film of the present invention has a standard deviation of the amount of retardation of <3 nm, and a fitting parameter of the amount of retardation is |Asym50-1|*10 8 <10. Specifically, the standard deviation of the delay amount is, for example, 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, or 2.9 nm, but the present invention is not limited thereto. The delay amount fitting parameter |Asym50-1|* 108 is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9, but the present invention is not limited thereto, and preferably It is 0. When the standard deviation of the retardation amount is <3 nm and the fitting parameter is |Asym50-1|*10 8 <10, the PVA film has a uniform retardation amount and has good uniformity during stretching in the subsequent optical film preparation. properties, making the film less likely to tear. This is because the retardation amount of the PVA film is affected by the birefringence value and the film thickness; the birefringence value increases as the molecular orientation of polyvinyl alcohol increases, and the thicker the film, the more the optical path becomes longer, and the measured delay amount also becomes larger.
本発明のＰＶＡフィルムが有する最大遅延量は＜５５ｎｍであり、具体的には、例えば１ｎｍ、５ｎｍ、１０ｎｍ、１５ｎｍ、２０ｎｍ、２５ｎｍ、３０ｎｍ、３５ｎｍ、４０ｎｍ、４５ｎｍ、５０ｎｍ又は５４ｎｍであるが、本発明はこれらに限定されない。 The maximum retardation amount of the PVA film of the present invention is <55 nm, specifically, for example, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm or 54 nm, but the present invention The invention is not limited to these.
ＰＶＡフィルムの含水率が低すぎると、フィルム切れ現象が生じやすくなるため好ましくない。本発明のＰＶＡフィルムの含水率は＞２．０ｗｔ％であり、具体的には、例えば２．０ｗｔ％、２．５ｗｔ％、３．０ｗｔ％、３．５ｗｔ％、４．０ｗｔ％、４．５ｗｔ％、５．０ｗｔ％、５．５ｗｔ％、６．０ｗｔ％、６．５ｗｔ％、７．０ｗｔ％、７．５ｗｔ％、８．０ｗｔ％、８．５ｗｔ％、９．０ｗｔ％、９．５ｗｔ％又は１０．０ｗｔ％であるが、本発明はこれらに限定されない。しかしながら、含水率は高すぎるのも好ましくなく、含水率が高すぎると結晶化度が低くなりすぎて、ＰＶＡフィルムを水に浸漬後、過度に軟らかくなってしまい、フィルム切れ持生じやすくなる傾向がある。 If the water content of the PVA film is too low, it is not preferable because the film tends to break. The moisture content of the PVA film of the present invention is >2.0 wt%, specifically, for example, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4. 5wt%, 5.0wt%, 5.5wt%, 6.0wt%, 6.5wt%, 7.0wt%, 7.5wt%, 8.0wt%, 8.5wt%, 9.0wt%, 9. 5 wt% or 10.0 wt%, but the present invention is not limited thereto. However, it is also undesirable for the water content to be too high; if the water content is too high, the degree of crystallinity will be too low, and the PVA film will become excessively soft after being immersed in water, making it more likely that the film will break. be.
本発明中、上述の含水率測定方法の工程には、図１に示す通り、ＰＶＡフィルムのうちのＭＤ位置を、ＴＤ方向で端部から４０ｃｍ以内の範囲内とし、ＴＤ方向に沿って左、中、右で１０ｃｍ＊１０ｃｍの面積の試験片を３枚切り出すことが含まれる。次に、各試験片の初期重量Ｓ（ｇ）をそれぞれ秤量した。試験片を８３℃の乾燥器中に入れ、２０分間乾燥してから、取り出して乾燥皿に入れ、５分間冷却した後、乾燥後の重量Ｗ（ｇ）をそれぞれ秤量した。最後に、（（Ｓ－Ｗ）／Ｓ）×１００％という公式により含水率を計算した。 In the present invention, in the step of the above-mentioned moisture content measuring method, as shown in FIG. 1, the MD position of the PVA film is within 40 cm from the end in the TD direction, and the left, This includes cutting out three test pieces with an area of 10cm*10cm on the center and right sides. Next, the initial weight S (g) of each test piece was weighed. The test pieces were placed in a dryer at 83° C. and dried for 20 minutes, then taken out and placed in a drying dish, cooled for 5 minutes, and then the weight W (g) after drying was weighed. Finally, the water content was calculated using the formula ((SW)/S)×100%.
ＰＶＡフィルムの製造又は加工ではおそらく加工助剤が添加されるが、添加する加工助剤の種類、濃度及び添加量はＰＶＡフィルムの最終的なｐＨ値に影響を与え、ｐＨ値はさらにフィルム切れの可能性に間接的な影響を与える。本発明のＰＶＡフィルムのｐＨは５．５～８．５の間であり、具体的には、例えば５．５、６．０、６．５、７．０、７．５、８．０又は８．５であるが、本発明はこれらに限定されない。 Processing aids are probably added during the production or processing of PVA films, and the type, concentration and amount of processing aids added will affect the final pH value of the PVA film, which in turn will affect the film breakage. Indirectly affects the likelihood. The pH of the PVA film of the present invention is between 5.5 and 8.5, specifically for example 5.5, 6.0, 6.5, 7.0, 7.5, 8.0 or 8.5, but the present invention is not limited thereto.
本発明中、上述のｐＨ値測定方法の工程には、ＰＶＡフィルム約５ｇを１０５℃の乾燥器中に入れ、３時間乾燥してから、取り出して乾燥皿に入れて冷却し、乾燥後のＰＶＡフィルム４ｇを精秤することが含まれる。その後、ＰＶＡフィルムを切砕してから９６ｇの超純水を加え、蒸気を利用して加熱溶解した。冷却した後、ｐＨ測定計を用いてｐＨ値を測定した。 In the present invention, in the process of the above-mentioned pH value measurement method, approximately 5 g of PVA film is placed in a drying oven at 105°C, dried for 3 hours, and then taken out and placed in a drying dish to cool. This includes accurately weighing 4 g of film. Thereafter, the PVA film was cut into pieces, 96 g of ultrapure water was added, and the mixture was heated and dissolved using steam. After cooling, the pH value was measured using a pH meter.
本発明におけるＰＶＡフィルムの結晶面の粒子サイズは４～６ｎｍであり、具体的には、例えば４ｎｍ、４．５ｎｍ、５ｎｍ、５．５ｎｍ又は６ｎｍであるが、本発明はこれらに限定されない。 The particle size of the crystal plane of the PVA film in the present invention is 4 to 6 nm, specifically, for example, 4 nm, 4.5 nm, 5 nm, 5.5 nm or 6 nm, but the present invention is not limited thereto.
本発明における結晶面の粒子サイズ測定方法の工程には、ＰＶＡフィルムを必要な面積にカットした後、Ｘ線回折装置（ＸＲＤ）による分析を行うことが含まれ（Ｘ－ｒａｙ源：Ｃｕターゲット（ＣｕＫα，λ＝０．１５４０６０ｎｍ）；２θ測定範囲：８～３５o）、得られたデータは機会に組込まれたソフトウェアで分析を行うことに限定されず、その他のソフトウェア（例えばＰｅａｋＦｉｔ）を用いて分析を行ってもよい。 The steps of the method for measuring the particle size of crystal planes in the present invention include cutting a PVA film into a required area and then analyzing it with an X-ray diffraction device (XRD) (X-ray source: Cu target ( CuKα, λ = 0.154060 nm); 2θ measurement range: 8-35 o ), the data obtained is not limited to analysis with the built-in software, but can be analyzed using other software (e.g. PeakFit). Analysis may be performed.
本発明におけるＰＶＡフィルムのＭＤ方向の破断伸び率は＞４００％であり、具体的には、例えば４０１％、４３０％、４５０％、４８０％、５００％、５３０％、５５０％、５８０％、６００％、６５０％、６８０％、７００％、７３０％、７５０％、７８０％、８００％、８３０％、８５０％、８８０％、９００％、９３０％、９５０％、９８０％又は１０００％であるが、本発明はこれらに限定されない。 The elongation at break in the MD direction of the PVA film in the present invention is >400%, and specifically, for example, 401%, 430%, 450%, 480%, 500%, 530%, 550%, 580%, 600%. %, 650%, 680%, 700%, 730%, 750%, 780%, 800%, 830%, 850%, 880%, 900%, 930%, 950%, 980% or 1000%, The present invention is not limited thereto.
本発明中、上述のＭＤ方向の破断伸び率及び引張強さ測定方法は以下の通りである。Ａ４紙サイズのＰＶＡフィルムを準備し、２０℃、６５％ＲＨの恒温恒湿器に６時間入れた。ＭＤ及びＴＤ方向がそれぞれ１５０ｍｍ＊１５ｍｍサイズの試験片にカットした。試験片の厚さを測定した後、試験片を引張試験機に挟み、引張試験機のオペレーションプロセスを実行し、引張速度は１０００ｍｍ／ｍｉｎとし、試験片の厚さ、長さ、幅及び名称を入力し、引張試験を実行開始して、破断伸び率及び引張強さを記録した。 In the present invention, the method for measuring the elongation at break and tensile strength in the MD direction is as follows. A PVA film of A4 paper size was prepared and placed in a constant temperature and humidity chamber at 20° C. and 65% RH for 6 hours. It was cut into test pieces each having a size of 150 mm*15 mm in the MD and TD directions. After measuring the thickness of the test piece, put the test piece in the tensile tester, run the operation process of the tensile tester, and set the tensile speed to 1000mm/min, and record the thickness, length, width and name of the test piece. The tensile test was started and the elongation at break and tensile strength were recorded.
本発明のＰＶＡフィルムは、例えば偏光フィルム、ブルーライトカットフィルム、フィルターレンズなどの光学フィルムとすることができ、本発明はこれらに限定されない。好適には、本発明のＰＶＡフィルムは偏光フィルムとされ、偏光フィルムが有する偏光度は＞９９．８である。 The PVA film of the present invention can be used as an optical film such as a polarizing film, a blue light cutting film, or a filter lens, but the present invention is not limited thereto. Preferably, the PVA film of the present invention is a polarizing film, and the polarizing film has a degree of polarization of >99.8.
以下では、実施例と合わせて本発明についてより詳しく説明する。但し、それらの実施例は本発明をより容易に理解できるよう助けるためのものであり、本発明の範囲を限定するものではないことを理解されたい。 The present invention will be explained in more detail below along with examples. However, it should be understood that these examples are provided to help the invention be more easily understood and are not intended to limit the scope of the invention.
実施例１～４ Examples 1 to 4
ＰＶＡフィルムの製作：融点（Ｔｍ）がそれぞれ２３３．２１℃、２３３．２４℃、２３３．０１℃及び２３３．０８℃のポリビニルアルコール樹脂をポリビニルアルコール鋳造溶液の主要成分とし、本発明のＰＶＡフィルムの製造方法を用いて実施例１～４のＰＶＡフィルムを製作した。製造方法の操作条件は表２に示す通りである。 Production of PVA film: Polyvinyl alcohol resins with melting points (Tm) of 233.21°C, 233.24°C, 233.01°C and 233.08°C, respectively, are used as the main components of the polyvinyl alcohol casting solution to produce the PVA film of the present invention. PVA films of Examples 1 to 4 were manufactured using the manufacturing method. The operating conditions of the manufacturing method are as shown in Table 2.
比較例１～３ Comparative examples 1 to 3
ＰＶＡフィルムの製作：融点（Ｔｍ）がそれぞれ２３３．１５℃及び２３３．１７℃のポリビニルアルコール樹脂をポリビニルアルコール鋳造溶液の主要成分とし、本発明のＰＶＡフィルムと同じ製造方法で異なる操作条件を用いて比較例１～３のＰＶＡフィルムを製作した。製造方法の操作条件は表２に示す通りである。 Fabrication of PVA film: Polyvinyl alcohol resins with melting points (Tm) of 233.15°C and 233.17°C, respectively, were the main components of the polyvinyl alcohol casting solution, using the same manufacturing method as the PVA film of the present invention but using different operating conditions. PVA films of Comparative Examples 1 to 3 were produced. The operating conditions of the manufacturing method are as shown in Table 2.
実験例 Experimental example
ＰＶＡフィルムの特性分析：実施例１～４及び比較例１～３のＰＶＡフィルムにおける遅延量の標準偏差、最大遅延量、遅延量のフィッティングパラメータ、含水率及び結晶面の粒子サイズ、ＭＤ方向破断伸び率及びＭＤ方向引張強さをそれぞれ測定した。測定結果は表３に示す通りである。 Characteristic analysis of PVA film: Standard deviation of delay amount, maximum delay amount, fitting parameter of delay amount, moisture content and particle size of crystal plane, MD direction elongation at break in PVA films of Examples 1 to 4 and Comparative Examples 1 to 3 The tensile strength and MD direction tensile strength were measured. The measurement results are shown in Table 3.
偏光フィルムの製作：実施例１～４及び比較例１～３における各ＰＶＡフィルムを約３０℃の水中に浸漬し、それらを膨潤させた後、１回目の一軸延伸を行い、ＭＤ方向に向かって延伸して、延伸後の長さをＰＶＡフィルムの元の長さの２．０倍にした。次に、１回目の延伸後のＰＶＡフィルムを０．０３質量パーセントのヨウ素及び３質量パーセントのヨウ化カリウムが含まれた３０℃の水溶液中に浸漬し、２回目の一軸延伸を行い、ＭＤ方向に向かって延伸して、延伸後の長さをＰＶＡフィルムの元の長さの３．３倍にした。次に、２回目の延伸後のＰＶＡフィルムを３質量パーセントのヨウ化カリウム及び３質量パーセントのホウ酸が含まれた３０℃の水溶液中に浸漬し、３回目の一軸延伸を行い、ＭＤ方向に向かって延伸して、延伸後の長さをＰＶＡフィルムの元の長さの３．６倍にした。次に、３回目の延伸後のＰＶＡフィルムを５質量パーセントのヨウ化カリウム及び４質量パーセントのホウ酸が含まれた６０℃の水溶液中に浸漬し、４回目の一軸延伸を行い、ＭＤ方向に向かって延伸して、延伸後の長さをＰＶＡフィルムの元の長さの６．０倍にした。最後に、４回目の延伸後のＰＶＡフィルムを３質量パーセントのヨウ化カリウムが含まれた水溶液中に１５秒間浸漬した後、６０℃で４分間乾燥して、偏光フィルムを得た。次に、実施例１～４及び比較例１～３の偏光フィルムのフィルム切れ発現性を測定した。各測定結果は表３に示す通りである。 Production of polarizing film: Each PVA film in Examples 1 to 4 and Comparative Examples 1 to 3 was immersed in water at about 30°C to swell, and then uniaxially stretched for the first time in the MD direction. The stretched length was 2.0 times the original length of the PVA film. Next, the PVA film after the first stretching was immersed in an aqueous solution at 30°C containing 0.03% by mass of iodine and 3% by mass of potassium iodide, and a second uniaxial stretching was carried out in the MD direction. The length after stretching was 3.3 times the original length of the PVA film. Next, the PVA film after the second stretching was immersed in an aqueous solution at 30°C containing 3% by mass of potassium iodide and 3% by mass of boric acid, and a third uniaxial stretching was carried out in the MD direction. The length after stretching was made 3.6 times the original length of the PVA film. Next, the PVA film after the third stretching was immersed in an aqueous solution at 60°C containing 5% by mass of potassium iodide and 4% by mass of boric acid, and the fourth uniaxial stretching was carried out in the MD direction. The length after stretching was 6.0 times the original length of the PVA film. Finally, the PVA film after the fourth stretching was immersed for 15 seconds in an aqueous solution containing 3% by mass of potassium iodide, and then dried at 60° C. for 4 minutes to obtain a polarizing film. Next, the film breakage properties of the polarizing films of Examples 1 to 4 and Comparative Examples 1 to 3 were measured. The measurement results are shown in Table 3.
表３に示す通り、実施例１～４におけるＰＶＡフィルムの遅延量の標準偏差はいずれも＜３ｎｍであり、遅延量のフィッティングパラメータ│Ａｓｙｍ５０－１│＊１０8はいずれも＜１０であり、それらの偏光フィルムのフィルム切れ発現性は良好であった（５０００ｍでフィルム切れの発生なし）。これと比べて、比較例１～３のＰＶＡフィルムは、それぞれが遅延量の標準偏差が３ｎｍを上回っているか、遅延量のフィッティングパラメータ│Ａｓｙｍ５０－１│＊１０8が１０を上回っており、それらの偏光フィルムはフィルム切れ発現性が好ましくなく（５０００ｍでフィルム切れが１回、５０００ｍでフィルム切れが２回以上）、特に比較例２及び３は含水量が２％超、結晶面の粒子サイズが６ｎｍ超、及びｐＨ値が５．５未満と８．５超であり、結晶面の粒子サイズが大きすぎると、延伸時に大きな応力が生じ、延性が悪くなり、フィルム切れが生じる傾向にある。それらの偏光フィルムのフィルム切れ発現性は明らかに悪かった（５０００ｍでフィルム切れが２回以上）。本発明におけるＰＶＡフィルムの遅延量の標準偏差は＜３ｎｍであり、遅延量のフィッティングパラメータ│Ａｓｙｍ５０－１│＊１０8はいずれも＜１０であり、均一な遅延量を有し、延伸時において均一性を持った延伸が可能であり、フィルム切れの問題が生じにくかった。 As shown in Table 3, the standard deviation of the delay amount of the PVA films in Examples 1 to 4 is all <3 nm, and the fitting parameter of the delay amount |Asym50-1|* 108 is all <10; The polarizing film exhibited good film breakage (no film breakage occurred at 5000 m). In comparison, the PVA films of Comparative Examples 1 to 3 each have a standard deviation of the delay amount exceeding 3 nm, or a fitting parameter of the delay amount |Asym50-1|* 108 exceeds 10. The polarizing film has an unfavorable tendency to break (the film broke once at 5000 m, and the film broke twice or more at 5000 m). In particular, Comparative Examples 2 and 3 had a water content of more than 2% and a grain size of the crystal plane. If the grain size of the crystal plane is too large, such as a particle size of more than 6 nm and a pH value of less than 5.5 or more than 8.5, large stress will be generated during stretching, resulting in poor ductility and a tendency to break the film. These polarizing films had clearly poor film breakage (film breakage occurred two or more times at 5000 m). The standard deviation of the retardation amount of the PVA film in the present invention is <3 nm, and the fitting parameter |Asym50-1|* 108 of the retardation amount is all <10, so it has a uniform retardation amount and is uniform during stretching. It was possible to stretch the film with good properties, and the problem of film breakage was less likely to occur.
要約すると、本発明のＰＶＡフィルムは均一で対称な遅延量を有しており、後の光学フィルム調製に用いた場合、均一に延伸することができてフィルム切れが発生しにくく、偏光フィルムを製造する際の欠点が効果的に改善され、製造での歩留まり率が向上する。 In summary, the PVA film of the present invention has a uniform and symmetrical retardation amount, and when used for later optical film preparation, it can be stretched uniformly and film breakage is less likely to occur, making it easy to manufacture polarizing films. This effectively improves the manufacturing yield rate.
以上で本発明について詳細に説明したが、上述は本発明の好ましい実施例に過ぎず、本発明の実施範囲を限定するものではない。本発明の特許請求の範囲に基づく同等変化や修飾はいずれも本発明の特許請求の範囲に属するものである。 Although the present invention has been described in detail above, the above description is only a preferred embodiment of the present invention, and does not limit the scope of implementation of the present invention. All equivalent changes and modifications based on the scope of the claims of the present invention are included within the scope of the claims of the present invention.
Claims (9)
The optical film according to claim 8, wherein the polarizing film has a degree of polarization of >99.8.
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