200813132 九、發明說明： 【發明所屬之技術領域】 本發明係關於一聚乙烯醇膜之製備方法、一由該方法 所製備之聚乙烯醇膜、以及一由該聚乙烯醇膜所製得之極 5 化板，更尤指一種可被均勻地染色以及拉伸（由於其聚乙烯 醇膜具有優秀的表面均勻性）之聚乙烯醇膜之製備方法、一 由該方法所製備之聚乙烯醇膜、以及一由該聚乙烯醇膜所 製備之極化板。 10 【先前技術】 近年來，資訊科技（information technology，IT)工業的 • 發展具有很大的進展，因此當現代工業社會中朝向高度資 訊社會發展時，資訊科技發展下的產物液晶顯示器（LCD) 已被發展成作為傳達各種資訊的媒介。 15 在平面顯示器裝置如LCD或有機電致發光器（el)中， 於基板表面通常具有一極化板，可防止外界光線反射朝向 φ 顯示圖像之螢幕，使得使用者可適當地看到螢幕。 極化板黏附於平面顯示器（如LCD或有機EL)之液晶組 立基板（cell)的兩側，因而當作液晶顯示面板的一部分。該 20 液晶顯示面板之結構為液晶組立基板的兩侧皆黏附有極化 板。圖1係為該極化板之一實施態樣之示意圖。 如圖1所示，極化板1包括一極化片6配置於其中間部 位、以及保護膜2、3經由壓感黏著層4、5而黏著於極化片6 之兩側。 200813132 該保護膜2、3係配置於極化片6之兩側，以保護極化片 6不艾損。極化片6黏著於液晶組立基板之前，該上層保護 膜2(—離形膜)會被撕下並丟棄，如此使壓感黏著層*暴露出 來，以作為極化片6與液晶組立基板黏著之中間媒介。極化 5片6黏著於液晶組立基板後，該下層保護膜3亦會被撕去並 丟棄。同時，黏附於保護膜3之壓感黏著層5(黏著於保護膜 3)亦會隨著一同被撕去。保護膜2、3可由酯類樹脂（如ρΕτ) 製備得到。 ® 極化片6(配置於其保護膜2、3之間）係包括一極化片層 1〇 1〇與保護層7、8，該保護層7、8係藉由使用黏著層9分別穿 • 插於保護層7、8與極化片層10之間而黏著於極化片層1〇之 兩側。於此，該極化片層10 一般可為一聚乙烯醇聚合體 (PVA)(碘或二鉻染料係黏著於其上），且所使用之保護層 7、8可為二醋酸纖維素（triacetyi ceiiui〇se，TAC)等。 15 一般聚合物膜之中，已將光學材料（如：極化片）之焦點 集中於該聚乙浠醇膜上，因其同時具有優異的光學性質 _ (如：透光度與極化性質）以及優異的機械特性（如：彈性係 數、抗拉強度及抗張伸展率）。傳統的極化片主要使用於手 錶、電子計算機、汽車儀錶板、小型液晶電視、小型LCD 20筆記型電腦等領域。但近來對於具有優異極化性質之極化 片的發展需求越來越增加，並可大範圍應用於發展大型筆 記型電腦、大型彩色電視等。 爲提供一具有優異極化性質並於光學上使用之聚乙烯 醇極化板，該極化板表面需為均勻。但本領域傳統方法製 6 200813132 備之極化板不具充足之表面均勻性，因於連續性溶液澆鑄 (casting)製備聚乙烯醇膜之過程中，包含一塑化劑或一 ^面 活性劑（殘留於聚乙烯醇聚合物水溶液中）之蒸氣係不^句 地滞留於鑄筒之表面，而造成斑點出現在極化板表面。若 5製備大面積之極化板，由於完全移除極化板之污點非常困 難，因此大幅提升極化板之極化度（p〇larizati〇n degree)至今 仍為一困難的問題。 _ 【發明内容】 10 β因此，本發明之目的係在於解決習知技術之問題，並 提供一種具有優異的表面均勻性之聚乙烯醇膜的製備 法。 並且，本發明之另一目的係在於提供一種經由上述方 法所製備之聚乙烯醇膜。 15 ▲並且，本發明之又一目的係在於提供一種由該聚乙烯 醇膜所製備之極化板。 _ 為達到上述目的，本發明係提供一種聚乙烯醇膜之製 備方法，包括： (a) 混合聚乙烯醇、水、一塑化劑以及一介面活性劑 20 以製備一水溶液； (b) 當T型模之排出埠連續將水溶液洗鑄於一鑄筒 (casting drum)之表面時，使用一蒸氣汲取裝置吸取由排出 層之下表面所排出之蒸氣，其中該鑄筒係置於距離該τ型模 之排出埠-預定距離，並以一預定速率旋轉，且該蒸氣汲 25取裝置係配置於⑴及⑻之間之空間，⑴係為排出層之下表 200813132 面，該下表面係面對該鑄筒，且為排出埠排出水溶液後立 即形成，且該排出層之延伸線所具有之方向為向著該排出 埠，而（ii)係為該鑄筒之表面； (c) 乾燥澆鑄至鑄筒（drum)之水溶液而形成一初級聚 5 乙烯醇膜;以及 (d) 熱處理該初級聚乙烯醇膜。· 根據本發明聚乙烯醇膜之製備方法，該蒸氣汲取裝置 之吸入口較佳係配置於距離該模之排出埠一預定距 離，並配置反方向於該T型模之排出埠排出水溶液方向，以 10 確保水溶液排出之穩定性 並且如本發明聚乙烯醇膜之製備方法，一 τ型模（包 括蒸氣没取裝置之吸入口）之尾端係較佳配置平行於該排 出層:以確保水溶液排出之穩定性以及將排出層下表面排 出之蒸氣吸入之效率。 15 亚且，本發明係提供一由上述方法所製備之聚乙烯醇 膜。 本^明更提供-由上述方法製備之聚乙烯醇膜所製備 之極化板。 20 【實施方式】 在以下將以較佳實施例詳細描述本發明。 首先’一步一步地詳述本發明聚乙烯醇膜之製備方法。 (a)水溶液之製備 IV驟係將*乙烯醇、水、—塑化劑及-介面活性劑 5混合製得-水溶液。該聚乙烯醇（係為—包含乙烯醇作為重 8 200813132 複單元之聚合物)可經由將乙烯醋聚合物(聚合乙烯醋單體 而得至，0水解製備、接著將一乙稀醋單元皂化成一乙稀醇單 疋所製仔。舉例而言，該乙烯醋單體包括如甲酸乙稀醋、 醋酸乙烯醋、丙酸乙烯酉旨、戊酸乙烯醋、月桂酸乙烯醋、 5硬月曰&乙烯酉曰、苯曱酸乙烯醋、特戊酸乙烯醋（vinyl pivaliate)、瓦沙酸乙烯s旨（咖一咖_)等。於其之中較 佳係醋酸乙烯醋。當聚合乙烯醋單體時，只要不違背本發 明之精神與範圍之下，亦可以使用其他已知單體如乙稀及 丙烯進行共聚合。 10 該聚乙烯醇（經由乙稀酯單元息化製得）較加係具有皂 化f為95%或更多’更佳為99%或更多，而最佳為99 5%或 更多。並且，考量到所製備極化板之機械性質及溶液澆鑄 的加工性，該聚乙烯醇之平均聚合度較佳係於1，7〇〇至7,⑽〇 之範圍内，更佳為2,〇〇〇至5,〇〇〇之範圍内。 15 同日守，於此步驟期間，該水溶液中聚乙烯醇之含量範 圍較佳係於10至60重量百分比，更佳範圍係於2〇至4〇重量 百分比。若該聚乙烯醇之含量少於10重量百分比，水溶液 的黏性過低會造成形成膜層效率惡化，若該聚乙烯醇之含 量多於60重量百分比，所產生之不溶物會凝膠化而降低製 20 備膜層的均勻性。 此步驟中，該加入水溶液中之塑化劑用於增進膜層形 成時之加工性（processability)，所使用之塑化劑舉例包含有 多元醇化合物如丙三醇、乙二醇、聚乙二醇、或其混合物， 但不限於此。特別地，較佳係使用可將光學差異减小（由於 9 200813132 其與聚乙烯醇有好的相容性）之丙三醇。其塑化劑之含量， 以100重量份之聚乙烯醇為基準，較佳係於5至2〇重量份之 間。若該塑化劑之含量少於5重量份，則膜層會產生高度結 晶而影響極化板形成時之染色效能（dyeing perf〇而⑽）， 5而右該塑化劑之含量多於2〇重量份，則會破壞聚乙稀醇膜 之機械性質。 當該聚乙烯醇膜由鑄筒上剝下時，添加於水溶液之介 面活性劑是用來降低聚乙烯醇膜之剝離力使其容易被剝 下。並且，在此對該介面活性劑之種類無特別任何限制， 10只要為在溶液、水中具有優異的熱穩定性以及有好的分散 性之材料，皆可作為該介面活性劑。特別地，較佳係使用 具有好的分散性之介面活性劑（係由於其微小尺寸）作為極 化板之光學使用’以防止最終產物的光散射。 該介面活性劑舉例包括有：一經聚丙烯酸修飾之化合 15物、一經聚矽氧烷修飾之化合物、一聚氧乙烯醚 (polyoxyethylene ester)化合物等，但不限於此。考量該介 面活性劑的添加對預期效應及光學特性所造成的影響，該 介面活性劑之含量，以1〇〇重量份之聚乙烯醇為基準，較佳 係為0 · 01至1重量份之間。 20 此步驟中，其水係為一用以將反應混合物溶解或分散 之媒介。並且，在此對該水並無任何限制，而較佳係使用 去離子水。且該水係較佳混合含量係為使溶液澆鑄步驟中 所製備之混合物可具有較合適之黏性，亦可使用本發明所 屬領域習知之水含量，但本發明並不受限於此。 200813132 此步驟中，該混合聚乙烯醇、水、一塑化劑與一介面 活性劑之方法包括使用一混合槽（mixing tank)之方法、使用 一擠壓器（extruder)之方法、以及使用其兩方法共同之組合 方法等，而產出之混合物可被完全地混合而使得該混合中 5 沒有殘留未溶物。以下將為該混合方法作更詳細的描述。 首先，將聚乙烯醇洗滌以除去殘留於聚乙烯醇中之不纯 物，並將清洗過後之聚乙浠醇置於一熔化槽（melting tank)，並加入一塑化劑以及一介面活性劑並於90至180〇C溶 φ 解以製得一澆鑄溶液。 10 (b)水溶液之洗鑄 本步驟係將水溶液（由上述方法所製得）進行溶液澆鑄 (solution-cast)至一轉動之鑄筒上。當其水溶液洗鑄至其鑄 筒上時，且當澆鑄至鑄筒表面上之水溶液初步乾燥時，鑄 筒表面上則形成一薄膜。200813132 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD The present invention relates to a method for preparing a polyvinyl alcohol film, a polyvinyl alcohol film prepared by the method, and a film made of the polyvinyl alcohol film. The invention relates to a method for preparing a polyvinyl alcohol film which can be uniformly dyed and stretched (due to the excellent surface uniformity of the polyvinyl alcohol film), and a polyvinyl alcohol prepared by the method. A film, and a polarizing plate prepared from the polyvinyl alcohol film. 10 [Prior Art] In recent years, the development of information technology (IT) industry has made great progress. Therefore, when the modern industrial society is developing towards a high information society, the liquid crystal display (LCD) under the development of information technology It has been developed as a medium for conveying various information. 15 In a flat panel display device such as an LCD or an organic electroluminescent device (el), there is usually a polarizing plate on the surface of the substrate to prevent external light from being reflected toward the screen of the φ display image, so that the user can properly see the screen. . The polarizing plate is adhered to both sides of a liquid crystal display unit of a flat display such as an LCD or an organic EL, and thus is considered as a part of the liquid crystal display panel. The structure of the 20 liquid crystal display panel is such that a polarizing plate is adhered to both sides of the liquid crystal group vertical substrate. Fig. 1 is a schematic view showing an embodiment of the polarizing plate. As shown in Fig. 1, the polarizing plate 1 includes a polarizing plate 6 disposed at its intermediate portion, and the protective films 2, 3 are adhered to both sides of the polarizing plate 6 via the pressure-sensitive adhesive layers 4, 5. 200813132 The protective films 2 and 3 are disposed on both sides of the polarizing plate 6 to protect the polarizing plate 6 from damage. Before the polarizing plate 6 is adhered to the liquid crystal assembly substrate, the upper protective film 2 (the release film) is torn off and discarded, so that the pressure sensitive adhesive layer* is exposed to adhere to the liquid crystal assembly substrate as the polarizing plate 6. Intermediate medium. After the polarized 5 sheets 6 are adhered to the liquid crystal assembly substrate, the lower protective film 3 is also peeled off and discarded. At the same time, the pressure-sensitive adhesive layer 5 (adhered to the protective film 3) adhered to the protective film 3 is also peeled off together. The protective films 2, 3 can be prepared from an ester resin such as ρΕτ. The polarizing plate 6 (disposed between the protective films 2 and 3) includes a polarizing layer 1〇1〇 and protective layers 7, 8 which are respectively worn by using the adhesive layer 9. • Inserted between the protective layers 7, 8 and the polarizing layer 10 and adhered to both sides of the polarizing layer 1〇. Here, the polarizing sheet layer 10 may generally be a polyvinyl alcohol polymer (PVA) to which an iodine or chrome dye is adhered, and the protective layers 7, 8 used may be cellulose diacetate ( Triacetyi ceiiui〇se, TAC), etc. 15 Among the general polymer films, the focus of optical materials (such as polarizing plates) has been concentrated on the polyethylene glycol film because of its excellent optical properties (eg, transmittance and polarization properties). ) and excellent mechanical properties (such as: modulus of elasticity, tensile strength and tensile elongation). Traditional polarizers are mainly used in watches, electronic computers, car dashboards, small LCD TVs, and small LCD 20 notebook computers. However, there has been an increasing demand for the development of polarizing sheets having excellent polarization properties, and it has been widely used for the development of large-sized notebook computers and large-scale color televisions. In order to provide a polyvinyl alcohol polarizing plate having excellent polarization properties and optically used, the surface of the polarizing plate needs to be uniform. However, the polarizing plate prepared by the conventional method in the prior art does not have sufficient surface uniformity, and contains a plasticizer or a surfactant in the process of continuous solution casting to prepare a polyvinyl alcohol film. The vapor remaining in the aqueous solution of the polyvinyl alcohol polymer is not retained on the surface of the casting tube, causing spots to appear on the surface of the polarizing plate. If 5 large-area polarized plates are prepared, it is very difficult to completely remove the stain of the polarized plates, so that it is still a difficult problem to greatly increase the polarization of the polarized plates. SUMMARY OF THE INVENTION [10] Therefore, the object of the present invention is to solve the problems of the prior art and to provide a process for producing a polyvinyl alcohol film having excellent surface uniformity. Further, another object of the present invention is to provide a polyvinyl alcohol film produced by the above method. Further, another object of the present invention is to provide a polarizing plate prepared from the polyvinyl alcohol film. In order to achieve the above object, the present invention provides a method for preparing a polyvinyl alcohol film, comprising: (a) mixing polyvinyl alcohol, water, a plasticizer, and an surfactant 20 to prepare an aqueous solution; (b) The discharge of the T-die continuously continuously washes the aqueous solution on the surface of a casting drum, and uses a vapor extraction device to suck the vapor discharged from the lower surface of the discharge layer, wherein the casting tube is placed at a distance from the τ The discharge 埠 of the mold is a predetermined distance and is rotated at a predetermined rate, and the vapor raft 25 is disposed in a space between (1) and (8), and (1) is a surface of the lower layer of the surface of the discharge layer 200813132, the lower surface surface Forming the casting tube immediately after discharging the aqueous solution for discharge, and the extension line of the discharge layer has a direction toward the discharge port, and (ii) is the surface of the casting tube; (c) dry casting to An aqueous solution of a drum forms a primary poly5 vinyl alcohol film; and (d) heat treats the primary polyvinyl alcohol film. According to the method for preparing a polyvinyl alcohol film of the present invention, the suction port of the vapor pumping device is preferably disposed at a predetermined distance from the discharge port of the mold, and is disposed in a direction opposite to the discharge port of the T-die to discharge the aqueous solution. The stability of the aqueous solution discharge is ensured by 10 and, as in the preparation method of the polyvinyl alcohol film of the present invention, the tail end of a τ-type mold (including the suction port of the vapor detaching device) is preferably arranged parallel to the discharge layer: to ensure the aqueous solution The stability of the discharge and the efficiency of inhaling the vapor discharged from the lower surface of the discharge layer. Further, the present invention provides a polyvinyl alcohol film produced by the above method. Further, a polarizing plate prepared by a polyvinyl alcohol film prepared by the above method is provided. [Embodiment] Hereinafter, the present invention will be described in detail by way of preferred embodiments. First, the preparation method of the polyvinyl alcohol film of the present invention will be described in detail step by step. (a) Preparation of an aqueous solution IV A mixture of *vinyl alcohol, water, a plasticizer and an surfactant 5 was prepared to prepare an aqueous solution. The polyvinyl alcohol (which is a polymer comprising vinyl alcohol as a compound of weight 8 200813132) can be obtained by hydrolyzing an ethylene vinegar polymer (polymerized ethylene vine monomer, 0 hydrolysis, and then saponifying a ethyl vinegar unit). For example, the vinyl vinegar monomer includes, for example, ethyl formate vinegar, vinyl acetate vinegar, vinyl propionate, vinyl valeric acid, lauric acid, vinyl vinegar, 5 hardy &vinyl hydrazine, benzoic acid vinyl vinegar, vinyl pivaliate, vinyl oxalate ethate, etc. Among them, vinyl acetate vinegar is preferred. When the vinegar monomer is used, it is also possible to carry out copolymerization using other known monomers such as ethylene and propylene as long as it does not deviate from the spirit and scope of the present invention. 10 The polyvinyl alcohol (obtained by ethylene glycol unit) The saponification f has a saponification f of 95% or more, more preferably 99% or more, and most preferably 99 5% or more. Moreover, the mechanical properties of the prepared polarized plate and the processing of solution casting are considered. The average degree of polymerization of the polyvinyl alcohol is preferably from 1,7 to 7, (10) In the range, it is more preferably 2, 〇〇〇 to 5, 〇〇〇. 15 Same day, during this step, the content of polyvinyl alcohol in the aqueous solution is preferably in the range of 10 to 60% by weight, The preferred range is from 2〇 to 4〇 by weight. If the content of the polyvinyl alcohol is less than 10% by weight, the viscosity of the aqueous solution is too low, which may cause deterioration of the formation of the film layer, if the content of the polyvinyl alcohol is more than 60% by weight. Percentage, the insoluble matter produced will gel and reduce the uniformity of the prepared film layer. In this step, the plasticizer added to the aqueous solution is used to improve the processability of the film formation, and is used. The plasticizer is exemplified by a polyhydric alcohol compound such as glycerol, ethylene glycol, polyethylene glycol, or a mixture thereof, but is not limited thereto. In particular, it is preferred to use the optical difference to be reduced (due to 9 200813132) The glycerin has good compatibility with polyvinyl alcohol, and the content of the plasticizer is preferably between 5 and 2 parts by weight based on 100 parts by weight of the polyvinyl alcohol. If the content of the plasticizer is less than 5 parts by weight, the film layer Producing a high degree of crystallization which affects the dyeing performance when the polarized plate is formed (dyeing perf〇 (10)), 5 and the right plasticizer content of more than 2 parts by weight, will destroy the mechanical properties of the polyethylene film. When the polyvinyl alcohol film is peeled off from the casting cylinder, the surfactant added to the aqueous solution is used to reduce the peeling force of the polyvinyl alcohol film to be easily peeled off. Moreover, there is no such type of the surfactant. Any particular limitation, 10 may be used as the surfactant as long as it has excellent thermal stability in a solution or water and good dispersibility. In particular, it is preferred to use a surfactant having good dispersibility. (due to its small size) as the optical use of the polarizing plate to prevent light scattering of the final product. Examples of the surfactant include, but are not limited to, a polyacrylic acid-modified compound 15, a polyoxyalkylene-modified compound, a polyoxyethylene ester compound, and the like. Considering the effect of the addition of the surfactant on the expected effect and the optical properties, the content of the surfactant is preferably from 0.01 to 1 part by weight based on 1 part by weight of the polyvinyl alcohol. between. 20 In this step, the water system is a medium for dissolving or dispersing the reaction mixture. Further, there is no limitation on the water here, and deionized water is preferably used. Further, the water system is preferably mixed in such a manner that the mixture prepared in the solution casting step can have a suitable viscosity, and a water content conventionally known in the art can be used, but the present invention is not limited thereto. 200813132 In this step, the method of mixing polyvinyl alcohol, water, a plasticizer and an surfactant comprises a method of using a mixing tank, an method using an extruder, and using the same The two methods are combined in a combination method or the like, and the produced mixture can be completely mixed so that no undissolved matter remains in the mixture. The mixing method will be described in more detail below. First, the polyvinyl alcohol is washed to remove the impurities remaining in the polyvinyl alcohol, and the washed polyethylene glycol is placed in a melting tank, and a plasticizer and an surfactant are added. And dissolved at 90 to 180 ° C to obtain a casting solution. 10 (b) Aqueous solution washing This step is a solution-casting of an aqueous solution (prepared by the above method) onto a rotating casting drum. When the aqueous solution is washed onto its casting drum, and when the aqueous solution cast onto the surface of the casting drum is initially dried, a film is formed on the surface of the casting drum.
15 下作描述澆鑄步驟之特定實施例。於溫度為60至110°C 之情形下，將步驟（a)製得之水溶液經由一 T型模（溫度為80 赢 至100°C)澆鑄於鑄筒上，而得到一層膜。同時，其丁型模與 該鑄筒之距離較佳係維持在10mm或更少，且更佳為5mm或 更少。 20 圖2係為一傳統使用於製備聚乙烯醇膜之鑄造機之示 意圖。如圖2所示，該鑄造機包括一 T型模21、一鑄筒24以 及一控制筏22(用以控制排出之水溶液的量）。該鑄筒係連續 地向著箭頭A的方向作旋轉，且該水溶液（將聚乙烯醇、一 塑化劑以及一介面活性劑溶於水中而製得）係經由該T型模 11 200813132 均勾地排放出來’而經由排出埠於寬度方向上_於禱筒 之表面以形成一排出層25，且該排出層25接著與鑄筒之表 面接觸而形成—層薄膜。同時，蒸氣（水汽，以及塑化劑盘 介面活性劑之蒸氣）係由該排出層25散發出纟（由於出、 5層25具有-_或更高之高溫），且—些蒸氣係由排出層面 對鑄筒之下表面，朝向著鑄筒（B方向）排放出來，而一此基 氣係向著相反方向（C方向）由排出層之上表面排放出來。.、、、 該向著C方向排放出來之蒸氣並不會對該聚乙稀醇膜 有特別的影響（因其蒸氣會消逝於空氣中），但向著6方 10放出來的蒸氣則會附著於鑄筒上而造成膜表面的污染。也 就是說’既然洗鑄步驟中由水溶液所形成之蒸氣無法均勾 沾濕於鑄筒之表面上，其蒸氣則不會均勻地滯留於禱筒之 表面上，而因此於排出層附著於鑄筒後，其蒸氣則會立即 對膜層表面具有反向的作用。如上所述，當膜層完全 …：燥狀況時，該膜層表面則被向著3方向排放出來的蒸‘ >可染。此污染造成極化板（由該膜層製得）具有一不均勻的極 化度。 〜為了解決上述問題，本發明透過τ型模之排放埠於聚乙 烯醇水溶液連續土也洗鑄於禱筒之表面時Μ吏用一 如裝置吸取由排出層之下表面所排出之蒸氣’其中該 取裝置係配置於⑴及（Η)之間之空間，其⑴係為排出層之下 表面，該下表面係面對該鑄筒，且為排出埠排出水溶液後 立即开/成’且該排出層之延伸線具有之方向為向著該排出 埠，而其（ii)係為該鑄筒之表面。 12 200813132 圖3係為本發明之用於製備聚乙烯醇膜之一鑄造機之 示意圖。如圖3所示，於該T型模21之排出埠之一預定距離 置放該鑄筒24，並該鑄筒24以一預定速率旋轉。該聚乙烯 醇聚合物水溶液係經由T型模21之排出崞而連續投注於該 5 鑄筒24之表面上。一蒸氣汲取裝置23則將該排出層25之下 表面的蒸氣吸排出，其中該蒸氣汲取裝置係配置於⑴及（ii) 之間之空間，其（i)係為排出層25之下表面，該下表面係面 對該鑄筒24，且為T型模21之排出埠排出水溶液後立即形 φ 成，且該排出層之延伸線26所具有之方向為向著該排出 10 埠，而其（ii)係為該鑄筒24之表面。如圖3所示，為維持水 溶液排出的穩定性，一蒸氣汲取裝置23之吸入口（inlet port) 較佳係配置於一適當距離，以及於由該T型模21之排出埠排 出水溶液方向之反方向。蒸氣汲取裝置23之吸入口與Τ型模 之排出埠之距離較佳係於30至200mm之範圍内，以維持水 15 溶液排出的穩定性以及蒸氣吸入的效率。對於排出層25之 下表面之水溶液排出的穩定性以及蒸氣吸入的效率而言， 包括吸入口之蒸氣汲取裝置2 3之尾端較佳係配置於平行排 胃 出層25之位置，如此其蒸氣汲取裝置23則依附於T型模21 之背面，如圖3等所示。為考量到水溶液排出的穩定性以及 20 蒸氣吸入的效率，該蒸氣汲取裝置23之吸力較佳係於10至 600托耳(torrs)之範圍内，且更佳係於50至500托耳之範圍 内。 (c)初級膜層之行成 此步驟係將該水溶液澆鑄於鑄筒上而形成一聚乙烯醇 13 200813132 膜，將該膜由鑄筒上撕下並乾燥。本發明中，此步驟所形 成之該聚乙烯醇膜係指一初級聚乙浠醇膜。以下，將此步 驟作更詳細之描述。 步驟（b)中，當一膜層形成於一鑄筒上時，將膜層由鑄 5筒上剝下並經由一具有70至90°C之溫度的乾燥滾筒（drying roll)將該膜層乾燥，而完成本發明之一初級聚乙烯醇膜。 為有效的提高乾燥效率之方法可於該鑄筒周圍吹熱氣。該 熱氣之溫度較佳係於60至150。(：之間，且其與鑄筒之溫差較 φ 佳係維持在50°C使均勻地將膜層乾燥。 10 本务明中，δ亥轉筒之寬度並無特別限制，但較佳係為 2,400mm或更多，使保障運作穩定性，而剝離張力強度 tension strength)較佳係於〇.〇iN/mm或更小的範圍内，以將 膜層均勻地由该鑄筒剝離。為了降低剝離抗拉強度，澆鑄 形成膜層的步驟中較佳係具有1〇至4〇重量百分比之溼度， 15 更佳係20至30重量百分比之溼度。 該由鑄筒剝下之膜層可經由乾燥筒進行二次乾燥。於 二次乾燥時，為了於膜層兩侧皆維持一均勻微小結構，該 膜層係較佳經過至少六個滾筒，且更佳係至少十個滾筒。 當該膜層由鑄筒剥下時，若該膜層具有高澄度含量，外部 $力會造成膜層表面張力提高，故該鱗筒以及該一次乾燥 同之距離較佳係為20mm或更少，且更佳係1〇馳或更少。 並且，該乾燥滾筒較佳具有5〇至9〇〇c之溫度。 (d)熱處理 訂述方法所料之減聚乙_膜進行熱處理步驟 14 200813132 以確保其機械特性。該熱處理可使用傳統製備聚乙烯醇膜 步驟中之任一方法，為考量其膜層之機械特性、染色特性 以及拉伸特性，較佳係具有100至180°C之溫度，更佳係110 至140°C之溫度。並且，該熱處理較佳係進行50至120秒。 5 舉例而言，於熱處理過程中，一張力（tension)較佳係 0.04 N/mm或更小，且更佳係0.02 N/mm。熱處理過程中， 該熱處理膜層較佳係具有溼度含量為5重量百分比或更 少，且更佳係3重量百分比。 此步驟中，熱處理方法沒有特別限制，但可使用本發 10 明所屬領域中傳統熱處理方法。例如，可使用將膜層與高 溫滾筒接觸之一熱處理膜層之方法、或以高溫空氣熱處理 之方法（例如使用具有100至160 °C以氣漂浮方式（air floating manner)之熱空氣一），爲達到均勻的熱處理，該膜 層較佳係使用氣漂浮方式進行熱處理。 15 本發明之製備方法可更包括一控制上述聚乙烯醇膜熱 處理時之溼度的步驟。本發明中，該溼度控制步驟係用以 除去乾燥及熱處理步驟時產生之熱歷程（thermal history)， 而提高其染色特性以及拉伸特性，並改善極化性質。 本發明中該溼度控制方法並無特別限制，但可使用本 20 發明所屬領域習知用以控制溼度之條件。例如，該溼度控 制步驟係較佳於溫度60至150t：、溼度50至90%，且更佳係 溫度80至120°C、溼度50至80%之條件下進行。進行溼度控 制步驟之該聚乙烯醇膜較佳係具有溼度含量係4至10重量 百分比。 15 200813132 上述之該聚乙烯醇膜可使用本發明所屬領域傳統捲繞 技術進行捲繞，但本發明對此並無特別限制。 上述之該聚乙烯醇膜可使用本發明所屬領域傳統染色 及拉伸方法做染色及拉伸以製得一極化板。該使用於製作 5 極化板之聚乙烯醇膜較佳係具有30至120μιη之厚度，且更佳 係50至80μπι。若該聚乙烯醇膜之厚度少於3〇μηι，拉伸特性 可能會不足，若該膜層之厚度多於12〇>m時，則會造成膜層 染色不足。 本發明中，對於其染色步驟並無特別限制，但可使用 10 本發明所屬領域習知廣泛使用之染色步驟。例如，將該聚 乙烯醇膜置於一包含填以及碘化鉀之水槽中進行染色，為 一有效的方法。同時，該染色步驟可使用〇〇1i4〇g/L之碘 濃度以及1至70 g/L之碘化鉀濃度，且可於溫度加至仙它下 進行染色，但本發明並不對此有所限制。經由上述方式染 15色之該聚乙烯醇膜，可藉由浸泡及交聯於硼酸鹽水溶液 中，而防止染色上去之碘被揮發。該硼酸鹽水溶液中，硼 酸鹽之濃度較佳係5至50g/L，以及溫度較佳係4〇艺或更低。 並且，於本發明中，對於製備極化板之拉伸步驟並無 特別限制，且可使用本發明所屬領域習知廣泛使用之拉伸 20步驟。例如，該聚乙烯醇膜或染色後之聚乙烯醇膜較佳係 於30至8(TC預熱30秒至5分鐘，接著於”至⑽七拉伸3至1〇 次，較佳之溫度範圍為40至6〇它。本發明中，其聚乙烯醇 膜之染色及拉伸步料Μ考量先後順序。也就是，其聚 乙烯醇膜可先被染色，接著拉伸，或先進行拉伸再染色， 200813132 =巧稀醇膜可同時被拉伸及染色。較佳地，爲達到效 二。5 %·將♦乙埽醇膜進行染色，並於—包含硼酸水溶液 之水槽中進行拉伸。 一星*色及拉伸後之聚乙烯醇膜最後再進行乾燥以製得 5 7極化板。該製得之極化板具有優秀的機械特性，表面無 污染物，並具有非常優異的極化性質。 ♦ 綜上所述，本發明聚乙烯醇膜及其製備方法、以及由 該聚乙烯醇所製備之極化板，已作詳細描述。 在以下文字中將以實施例詳細描述本發明。然而該實 10施例僅A說明，並不會對發明權力之範圍有所限制。 實施例 實施例1 將具有平均聚合度3200以及皂化度99.9莫耳百分比之 聚乙烯醇於20°C以足夠的水洗滌，同時攪拌3〇分鐘以移除 15 殘留於該聚乙浠醇之不纯物（如，醋酸納)。洗滌後，將聚乙 烯醇進行脫水以調整其可溶性濃度。於此，該聚乙烯醇（脫 水後仍保有濕氣）係結成塊狀。該結塊之濕氣含量係調整至 50重量百分比。將該結塊置於一槽體中，以1 〇〇重量份之聚 乙烤醇為基準’加入12重置份之一塑化劑、丙三醇，以及 2〇 〇·ΐ重量份之介面活性劑、聚氧乙烯醚。接著，將水加入上 述之混合物使非揮發性（non-volatile)之組成濃度達到31重 量百分比，接著該非揮發性之組成則會被溶解。將該得到 之反應溶液於150°C攪拌7小時以移除不溶物，而得到一洗 鑄溶液。 17 200813132 使用一消泡擠壓機以去除於溶解過程中產生的泡沫， 而後濃縮於消泡步驟中自擠壓機流出之蒸氣，並再次注入 擠壓機，如此則可維持溶液的濃度。該消泡步驟係於95°C 進行，並於消泡步驟製得一無泡沫之澆鑄溶液。使用一齒 5 輪泵（gear pump)以定量提供T型模洗鑄溶液。為了移除溶液 中殘留之外物，交替裝置20μιη及5μηι之瀘、器緊鄰齒輪泵以 移除細微的外物。並於Τ型模之前裝置一靜態混合器（static mixer)以避免洗鑄溶液溫度的不均勻。 使用之該T型模具有2,700mm的寬度、0.5 mm的吐出缺 10 口（lip gap)以及5 mm之空氣缺口（air gap)，並將其溫度維持 於95°C。並使用一蒸氣汲取裝置（裝置於T型模背面，如圖3 所示）移除澆鑄分界面所產生之蒸氣。同時，將該蒸氣汲取 裝置維持於500托耳之吸力。 使用之該鑄筒具有3,200 mm的寬度以及2,000 mm之直 15 徑，並將其溫度維持於90°C，而吹繞於鑄筒表面之熱空氣 溫度則維持在120°C。該鑄筒之旋轉速率維持於2 m/min， 待膜層由鑄筒剝下後，將膜層維持於20重量百分比之溼度。 將該鑄筒與第一乾燥筒之距離拉近至10mm，以維持低 的剝離張力強度。11個乾燥筒上下交替以使維持時間拉長 20 至最大，並且，為了避免該膜層於乾燥過程中被拉伸，將 滾筒之速率以一次降低5%而使膜層到達最後一個滚筒。該 乾燥筒係維持在80°C的溫度，且乾燥後該膜層中的溼度含 量為7重量百分比。 製得之膜層係使用一氣漂浮方式進行熱處理。該熱處 18 200813132 理之溫度係為130°C，且熱處理之時間係為60秒。熱處理後 該膜層中之溼度含量係為2重量百分比。熱處理後之該膜層 係，於85°C及相對65%之溼度，進行一溼·度控制步驟使達到 溼度含量為6重量百分比。製得之膜層接著切割成寬為 5 2,400mm且厚度為75μιη之帶狀，以製得一表面均勻之聚乙 烯醇膜。 將該製得之聚乙烯醇膜置於25°C水中使其膨脹，並接 著於一包含碘以及含碘鎘化物之水溶液中進行染色。同時 間，碘之濃度為0.5 g/L，且碘：碘化鉀之比例係調整至1:5。 10 接著，將該聚乙烯醇膜於50°C含有反應溶液（硼酸濃度為30 g/L)之水浴中拉伸5次，並乾燥製得一極化板。製得之該極 化板其極化度為99.9%。並且，可製得一不具有光學性污染 物之極化板。 15 實施例2 爲製備一極化板，如實施例1相同方法製備本實施例之 具有優秀表面均勻性之聚乙烯醇膜，但其蒸氣汲取裝置(配 置於T型模之背面）之吸力係為100托耳。所製得之極化板 具有99.9 %之極化度。 20 實施例3 使用一具有2,600之聚合度以及99.9 mol%之皂化度的 聚乙烯醇以製備一澆鑄溶液，調整此澆鑄溶液之非揮發性 組成至最終濃度為40重量百分比，其中該非揮發性組成係 25 包含12重量百分比之塑化劑，以及0.07重量百分比之介面 200813132 活性劑。本實施例係重複實施例1中之相同方法，除了上述 步驟製備之聚乙烯醇膜其厚度係為7 5 μπι。產出之膜層同實 施例1相同方式進行染色/拉伸步驟以製得一極化板。製得 之該極化板具有99.8 %之極化度。 比較例1 同實施例1相同方法製備本比較例之一聚乙烯醇膜，除 了溶液澆鑄步驟中不使用蒸氣汲取裝置吸取蒸氣。該製備 之聚乙烯醇膜於寬度方向上具有一條狀外觀，而一將聚乙 10 烯醇膜拉伸4.7次所製得之極化板，可能會由於極化板上的 光學性污染物而不能使用。且如此製得之膜層具有低平均 極化度為99.5 %。 效能之評估 15 極^(匕度（polarization degree) 本發明中，測量兩個重疊極化板之透光度，並根據以 下方程式1計算出極化度。測量儀器係由N&K Technology 製造之n&kl280分析儀。 方裎式1 極化度（％)=A specific embodiment of the casting step is described below. The aqueous solution obtained in the step (a) was cast on a casting mold through a T-die (temperature of 80 to 100 ° C) at a temperature of 60 to 110 ° C to obtain a film. At the same time, the distance between the butt mold and the casting cylinder is preferably maintained at 10 mm or less, and more preferably 5 mm or less. 20 Fig. 2 is a schematic view of a conventional casting machine for producing a polyvinyl alcohol film. As shown in Fig. 2, the casting machine includes a T-die 21, a casting drum 24, and a control port 22 (for controlling the amount of the discharged aqueous solution). The casting tube is continuously rotated in the direction of the arrow A, and the aqueous solution (prepared by dissolving polyvinyl alcohol, a plasticizer and an surfactant in water) is hooked through the T-die 11 200813132 The discharge layer is formed by discharging the crucible in the width direction to form a discharge layer 25, and the discharge layer 25 is then brought into contact with the surface of the casting cylinder to form a film. At the same time, the vapor (water vapor, and the vapor of the plasticizer disk interface active agent) is emitted from the discharge layer 25 (due to the 5 layers 25 having a high temperature of -_ or higher), and some vapors are discharged. The layer faces the lower surface of the casting cylinder and is discharged toward the casting cylinder (direction B), and the base gas is discharged from the upper surface of the discharge layer in the opposite direction (C direction). ., , , The vapor emitted to the C direction does not have a special effect on the polyethylene film (because its vapor will disappear in the air), but the vapor released to the 6 side 10 will adhere to The surface of the casting tube causes contamination of the surface of the membrane. That is to say, since the vapor formed by the aqueous solution in the washing step cannot be wetted on the surface of the casting drum, the vapor does not uniformly stay on the surface of the prayer cone, and thus the discharge layer adheres to the casting. Immediately after the cartridge, its vapor will have a reverse effect on the surface of the membrane. As described above, when the film layer is completely dry, the surface of the film layer is smeared by the steam discharged toward the three directions. This contamination causes the polarizing plate (made from the film layer) to have a non-uniform degree of polarization. In order to solve the above problems, the present invention is used to suck the vapor discharged from the lower surface of the discharge layer by using a device such as a discharge of a τ-type mold while the continuous aqueous solution of the aqueous solution of polyvinyl alcohol is also cast on the surface of the prayer cone. The taking device is disposed in a space between (1) and (Η), wherein (1) is a lower surface of the discharge layer, the lower surface faces the casting tube, and is immediately opened/formed after discharging the aqueous solution. The extension line of the discharge layer has a direction toward the discharge port, and (ii) is the surface of the casting tube. 12 200813132 Fig. 3 is a schematic view showing a casting machine for producing a polyvinyl alcohol film of the present invention. As shown in Fig. 3, the casting tube 24 is placed at a predetermined distance from the discharge port of the T-die 21, and the casting tube 24 is rotated at a predetermined rate. The aqueous solution of the polyvinyl alcohol polymer is continuously bet on the surface of the 5 casting tube 24 via the discharge enthalpy of the T-die 21. A vapor scavenging device 23 discharges the vapor on the lower surface of the discharge layer 25, wherein the vapor scooping device is disposed in a space between (1) and (ii), wherein (i) is the lower surface of the discharge layer 25. The lower surface faces the casting tube 24, and is immediately formed into a discharge 埠 of the T-die 21 after discharging the aqueous solution, and the extension line 26 of the discharge layer has a direction toward the discharge 10 埠, and Ii) is the surface of the casting tube 24. As shown in FIG. 3, in order to maintain the stability of the aqueous solution discharge, the inlet port of the vapor scooping device 23 is preferably disposed at an appropriate distance, and is discharged from the discharge port of the T-die 21 in the direction of the aqueous solution. The opposite direction. The distance between the suction port of the vapor scooping device 23 and the discharge port of the die is preferably in the range of 30 to 200 mm to maintain the stability of the discharge of the water 15 solution and the efficiency of vapor inhalation. For the stability of the aqueous solution discharge on the lower surface of the discharge layer 25 and the efficiency of vapor suction, the tail end of the vapor extraction device 23 including the suction port is preferably disposed at the position of the parallel discharge layer 25, such that the vapor The picking device 23 is attached to the back of the T-die 21 as shown in FIG. In order to take into account the stability of the aqueous solution discharge and the efficiency of the 20 vapor inhalation, the suction of the vapor extraction device 23 is preferably in the range of 10 to 600 tors, and more preferably in the range of 50 to 500 torr. Inside. (c) Formation of the primary film layer This step is to cast the aqueous solution onto a casting drum to form a polyvinyl alcohol 13 200813132 film which is torn off from the casting drum and dried. In the present invention, the polyvinyl alcohol film formed in this step means a primary polyethylene glycol film. This step is described in more detail below. In the step (b), when a film layer is formed on a casting cylinder, the film layer is peeled off from the casting cylinder and the film layer is passed through a drying roll having a temperature of 70 to 90 ° C. It is dried to complete a primary polyvinyl alcohol film of the present invention. In order to effectively increase the drying efficiency, hot gas can be blown around the casting drum. The temperature of the hot gas is preferably from 60 to 150. (: between, and the temperature difference from the casting cylinder is better than φ. Maintaining the temperature at 50 ° C to uniformly dry the film layer. 10 In the present invention, the width of the δ-Hale drum is not particularly limited, but is preferably It is 2,400 mm or more to ensure the stability of the operation, and the tensile strength is preferably in the range of 〇.iN/mm or less to uniformly peel the film layer from the casting can. In order to reduce the peeling tensile strength, the step of casting the film layer preferably has a humidity of from 1 to 4% by weight, more preferably from 15 to 30% by weight. The film layer peeled off from the casting can be subjected to secondary drying through a drying cylinder. In the case of secondary drying, in order to maintain a uniform microstructure on both sides of the film layer, the film layer preferably passes through at least six rolls, and more preferably at least ten rolls. When the film layer is peeled off from the casting tube, if the film layer has a high degree of sufficiency, the external force will increase the surface tension of the film layer, so the distance between the scale and the primary drying is preferably 20 mm or less. And better is 1 Coach or less. Also, the drying drum preferably has a temperature of 5 〇 to 9 〇〇c. (d) Heat treatment The heat-reduction step of the polycondensation of the film as described in the specification is carried out 14 200813132 to ensure its mechanical properties. The heat treatment may be carried out by any one of the conventional steps of preparing a polyvinyl alcohol film, in order to consider the mechanical properties, dyeing properties and tensile properties of the film layer, preferably having a temperature of 100 to 180 ° C, more preferably 110 to Temperature of 140 ° C. Also, the heat treatment is preferably carried out for 50 to 120 seconds. 5 For example, during the heat treatment, a tension is preferably 0.04 N/mm or less, and more preferably 0.02 N/mm. The heat-treated film layer preferably has a moisture content of 5 wt% or less, and more preferably 3 wt%, during the heat treatment. In this step, the heat treatment method is not particularly limited, but a conventional heat treatment method in the field to which the present invention pertains can be used. For example, a method of heat-treating a film layer by contacting the film layer with a high-temperature roller, or a method of heat-treating a high-temperature air (for example, using hot air having an air floating manner of 100 to 160 ° C) may be used. In order to achieve uniform heat treatment, the film layer is preferably heat treated using a gas floating method. The preparation method of the present invention may further comprise a step of controlling the humidity of the above polyvinyl alcohol film during heat treatment. In the present invention, the humidity control step is used to remove the thermal history generated during the drying and heat treatment steps, thereby improving the dyeing characteristics and the tensile properties, and improving the polarization properties. The humidity control method in the present invention is not particularly limited, but conditions for controlling humidity which are conventionally known in the art of the present invention can be used. For example, the humidity control step is preferably carried out at a temperature of 60 to 150 t:, a humidity of 50 to 90%, and more preferably a temperature of 80 to 120 ° C and a humidity of 50 to 80%. The polyvinyl alcohol film subjected to the humidity control step preferably has a moisture content of 4 to 10% by weight. 15 200813132 The above polyvinyl alcohol film can be wound using the conventional winding technique in the field to which the present invention pertains, but the present invention is not particularly limited thereto. The above polyvinyl alcohol film can be dyed and drawn by a conventional dyeing and stretching method in the field to which the present invention pertains to obtain a polarizing plate. The polyvinyl alcohol film used for the production of the 5-polarized plate preferably has a thickness of 30 to 120 μm, and more preferably 50 to 80 μm. If the thickness of the polyvinyl alcohol film is less than 3 〇 μη, the tensile properties may be insufficient, and if the thickness of the film layer is more than 12 Å > m, the film may be insufficiently dyed. In the present invention, the dyeing step is not particularly limited, but a dyeing step widely used in the art to which the present invention pertains can be used. For example, it is an effective method to place the polyvinyl alcohol film in a water bath containing the filling and potassium iodide. Meanwhile, the dyeing step may use an iodine concentration of 〇〇1i4 〇g/L and a potassium iodide concentration of 1 to 70 g/L, and may be dyed under temperature to the scent, but the present invention is not limited thereto. The polyvinyl alcohol film dyed in 15 colors as described above can be prevented from being volatilized by the immersion and crosslinking in the borate aqueous solution. In the aqueous borate solution, the concentration of the borate is preferably 5 to 50 g/L, and the temperature is preferably 4 or less. Further, in the present invention, the stretching step for preparing the polarizing plate is not particularly limited, and the stretching 20 step which is widely used in the art to which the present invention pertains can be used. For example, the polyvinyl alcohol film or the dyed polyvinyl alcohol film is preferably 30 to 8 (TC preheated for 30 seconds to 5 minutes, followed by stretching to 3 to 1 time at "to 10", preferably in a temperature range It is 40 to 6 。. In the present invention, the dyeing and stretching steps of the polyvinyl alcohol film are sequentially determined. That is, the polyvinyl alcohol film can be dyed first, then stretched, or stretched first. Re-dyeing, 200813132 = The film can be stretched and dyed at the same time. Preferably, in order to achieve the effect of 5%, the ketone film is dyed and stretched in a water bath containing an aqueous solution of boric acid. The one-star color and the stretched polyvinyl alcohol film are finally dried to obtain a 57-polarized plate. The obtained polarized plate has excellent mechanical properties, has no surface contamination, and has excellent properties. Polarization properties ♦ In summary, the polyvinyl alcohol film of the present invention, a preparation method thereof, and a polarizing plate prepared from the polyvinyl alcohol have been described in detail. In the following text, the embodiment will be described in detail. Invention. However, the embodiment of the real 10 is only A, and does not limit the scope of invention. Limitations. EXAMPLES Example 1 Polyvinyl alcohol having an average degree of polymerization of 3200 and a saponification degree of 99.9 moles was washed with sufficient water at 20 ° C while stirring for 3 minutes to remove 15 residues remaining in the polyethylene. An alcoholic impurity (eg, sodium acetate). After washing, the polyvinyl alcohol is dehydrated to adjust its soluble concentration. Here, the polyvinyl alcohol (which retains moisture after dehydration) is tied into a block. The moisture content was adjusted to 50% by weight. The agglomerate was placed in a tank and added to the 12-replacement portion of a plasticizer, glycerol based on 1 part by weight of the polyethylene glycol. And 2 parts by weight of the surfactant, polyoxyethylene ether. Then, water is added to the above mixture to achieve a non-volatile composition concentration of 31% by weight, followed by the non-volatile composition Then, the obtained reaction solution was stirred at 150 ° C for 7 hours to remove insoluble matter to obtain a washing solution. 17 200813132 A defoaming extruder was used to remove the foam generated during the dissolution process, Concentrated in defoaming The vapor exiting the extruder is injected into the extruder again, and the concentration of the solution is maintained. The defoaming step is carried out at 95 ° C, and a foam-free casting solution is obtained in the defoaming step. A toothed pump was used to quantitatively provide a T-die wash solution. In order to remove residual foreign matter in the solution, alternate devices of 20 μm and 5 μm were placed next to the gear pump to remove fine foreign matter. A static mixer is placed in front of the Τ mold to avoid uneven temperature of the washing solution. The T-die has a width of 2,700 mm, a gap of 0.5 mm, and a lip gap of 5 The air gap of mm was maintained at 95 °C. The vapor generated by the casting interface is removed using a vapor extraction device (on the back of the T-die, as shown in Figure 3). At the same time, the vapor extraction device was maintained at a suction of 500 Torr. The casting drum used has a width of 3,200 mm and a straight diameter of 2,000 mm, and maintains the temperature at 90 ° C, while the hot air temperature blown around the surface of the casting drum is maintained at 120 ° C. The casting speed of the casting was maintained at 2 m/min, and the film was maintained at a moisture content of 20% by weight after the film was peeled off from the casting tube. The distance between the casting cylinder and the first drying cylinder was pulled up to 10 mm to maintain a low peeling tensile strength. The 11 drying cylinders were alternately up and down to extend the holding time by 20 to the maximum, and, in order to prevent the film from being stretched during the drying process, the speed of the drum was reduced by 5% at a time to bring the film to the last drum. The drying cylinder was maintained at a temperature of 80 ° C, and the moisture content in the film layer after drying was 7 wt%. The resulting film layer was heat treated using a gas floating method. The hot spot 18 200813132 has a temperature of 130 ° C and a heat treatment time of 60 seconds. The moisture content in the film after heat treatment was 2% by weight. The film layer after the heat treatment was subjected to a humidity control step at 85 ° C and a relative humidity of 65% so as to achieve a moisture content of 6 wt%. The resulting film layer was then cut into strips having a width of 5 2,400 mm and a thickness of 75 μm to obtain a uniform surface polyvinyl alcohol film. The obtained polyvinyl alcohol film was placed in water at 25 ° C to be expanded, and then dyed in an aqueous solution containing iodine and cadmium iodide. At the same time, the concentration of iodine was 0.5 g/L, and the ratio of iodine: potassium iodide was adjusted to 1:5. 10 Next, the polyvinyl alcohol film was stretched 5 times in a water bath containing a reaction solution (boric acid concentration of 30 g/L) at 50 ° C, and dried to obtain a polarizing plate. The polarizing plate obtained had a polarization of 99.9%. Also, a polarizing plate having no optical contaminants can be obtained. 15 Example 2 To prepare a polarizing plate, a polyvinyl alcohol film having excellent surface uniformity of the present example was prepared in the same manner as in Example 1, but the suction system of the vapor extraction device (disposed on the back side of the T-die) was used. It is 100 Torr. The polarized plate produced had a degree of polarization of 99.9%. 20 Example 3 A polyvinyl alcohol having a degree of polymerization of 2,600 and a degree of saponification of 99.9 mol% was used to prepare a casting solution, and the non-volatile composition of the casting solution was adjusted to a final concentration of 40% by weight, wherein the non-volatile composition Line 25 contains 12 weight percent plasticizer and 0.07 weight percent interface 200813132 active agent. This example was repeated in the same manner as in Example 1, except that the polyvinyl alcohol film prepared in the above procedure had a thickness of 7 5 μm. The film layer produced was subjected to a dyeing/stretching step in the same manner as in Example 1 to obtain a polarizing plate. The polarized plate produced had a degree of polarization of 99.8%. Comparative Example 1 A polyvinyl alcohol film of this comparative example was prepared in the same manner as in Example 1, except that the vapor extraction device was used to extract vapor in the solution casting step. The prepared polyvinyl alcohol film has a strip-like appearance in the width direction, and a polarized plate obtained by stretching the poly(10) enol film by 4.7 times may be due to optical contaminants on the polarized plate. can not be used. The film thus obtained had a low average polarization of 99.5%. Evaluation of Efficacy 15 Polarization Degree In the present invention, the transmittance of two overlapping polarizing plates is measured, and the degree of polarization is calculated according to Equation 1. The measuring instrument is manufactured by N&K Technology. n&kl280 analyzer. Square 裎1 Polarization (%)=
HrH2H1+H2 X 100 於方程式1中，Hi代表水平重疊的極化板的透光度，而 H2代表垂直重疊的極化板的透光度。測量中所使用的光具 有400至700 nm的波長，而平均極化度係相同波長下於極化 20 20 200813132 度測量完成後計算得到。並且，對該極化板進行外觀檢查， 若膜層外觀均勻並且不具有任何污染物則以〇作標示，若 外觀不佳具有污染物則以X作標示。 實施例與比較例之結果如下表1所示。 表1HrH2H1+H2 X 100 In Equation 1, Hi represents the transmittance of the horizontally overlapping polarizing plates, and H2 represents the transmittance of the vertically overlapping polarizing plates. The light used in the measurement has a wavelength of 400 to 700 nm, and the average polarization is calculated at the same wavelength after polarization 20 20 200813132. Moreover, the polarized plate is visually inspected, and if the film layer is uniform in appearance and does not have any contaminants, it is marked with enamel, and if the appearance is poor, the contaminant is marked with X. The results of the examples and comparative examples are shown in Table 1 below. Table 1
實施例 比較例 1 2 3 1 水溶液之組 成 聚乙烯醇(重量百分比） 27.28 27.28 35.2 27.28 丙三醇(重量份） 12 12 12 12 介面活性劑（重量份） 0.1 0.1 0.07 0.1 非揮發性化合物 (重量百分比) 31 31 40 31 洗鑄 吸入裝置之吸力(托耳） 500 100 500 - 染色/拉伸 能力 碘(g/L) 0.5 0.5 0.5 0.5 碘化鉀(g/L) 2.5 2.5 2.5 2.5 拉伸能力(次數） 5.0 5.0 5.0 4.7 聚乙烯醇膜 外觀 佳 佳 佳 不佳 聚乙烯醇極 化板 極化度（％) 99.9 99.9 99.8 99.5 光學性污染物 〇 〇 〇 XEXAMPLES Comparative Example 1 Composition of 2 3 1 aqueous solution Polyvinyl alcohol (% by weight) 27.28 27.28 35.2 27.28 Glycerol (parts by weight) 12 12 12 12 Interfacial surfactant (parts by weight) 0.1 0.1 0.07 0.1 Non-volatile compound (weight Percentage) 31 31 40 31 Suction of the casting inhalation device (Torr) 500 100 500 - Dyeing/stretching ability Iodine (g/L) 0.5 0.5 0.5 0.5 Potassium iodide (g/L) 2.5 2.5 2.5 2.5 Tensile capacity (number of times) 5.0 5.0 5.0 4.7 Polyvinyl alcohol film appearance Jiajiajia poor polyvinyl alcohol polarized plate polarization (%) 99.9 99.9 99.8 99.5 Optical contaminant 〇〇〇 X
如表1所示之結果，相較於比較例1之聚乙烯醇膜（製備 過程中沒有蒸氣吸取過程），可看出實施例1至3之聚乙烯醇 膜（具有排出澆鑄裝置之背面裝置有一蒸氣汲取裝置，並以 10 一定壓吸取蒸氣）其表面外觀均勻且不具有污染物，而比較 例1之聚乙烯醇膜外觀則發現有污染物。並且，當該聚乙烯 21 200813132 醇膜被染色及拉伸以製備一極化板時，該實施例丨至3製備 之極化板具有99·8至99.9 %之極化度且無光學性污染物出 現，但比較例1製備之極化板具有99 5%之極化度（其低於實 施例1-3極化板之極化度>，並且有觀察到光學性污染物的出 5現。據估計該溶液澆鑄步驟中形成之蒸氣，會於膜層之表 面產生如齒痕之污染物。 產業利用性 如本發明之方法，當聚乙烯醇水溶液經由τ型模之排出 10埠連續澆鑄於鑄筒之表面上，該由排出層之下表面排出之 瘵氣係使用一無氣汲取裝置進行吸取，其中該蒸氣汲取裝 置係置放於⑴及（ii)之間的空間，其⑴係為排出層之下表 面，該下表面係面對該鑄筒，且為排出埠排出水溶液後立 即形成，且該排出層之延伸線所具有之方向為向著該排出 15埠，而其（!i)係為該轉筒之表面。因此，既然可避免蒸氣附 著於膜層及鑄筒表面而產生污染物，本發明聚乙烯醇膜之 製備方法便可有效增進聚乙烯醇膜表面之均勻性。同樣 地，由該聚乙烯醇膜製備之聚乙烯醇極化板（於其大表面上） 則具有優秀的極化性質。 20 本發明之實施方案其為用以闡明目的之用，已熟習技 術之士可在不違背本發明專利權之原領域範圍及其精神之 形況下進行進行各種不同修飾、增加以及取代。 【圖式簡單說明】 22 200813132 本發明較佳實施例中這些及其他特徵、態樣、及優點， 將由以上更詳細之解說並伴隨以下圖示而得到更清楚的理 解。 圖1係為一傳統極化板之實施例之部分結構圖。 5 圖2係為一傳統用於製備聚乙烯醇膜之鑄造機之示意圖。 圖3係為本發明一實施例中聚乙烯醇膜之製備方法所使用 之每造機示意圖。 【主要元件符號說明】 1 極化板 21 T型模 2, 3 保護膜 22 控制筏 4, 5 壓感黏著層 23 蒸氣没取裳置 7, 8 保護層 24 鑄筒 6 極化片 25 排出層 9 黏著層. 26 延伸線 10 極化片層 23As shown in Table 1, the polyvinyl alcohol film of Examples 1 to 3 (the back device having the discharge casting device) can be seen as compared with the polyvinyl alcohol film of Comparative Example 1 (there is no vapor suction process in the preparation process). There is a vapor scooping device and the vapor is sucked at a certain pressure of 10). The surface thereof is uniform in appearance and has no contaminants, and the appearance of the polyvinyl alcohol film of Comparative Example 1 is found to be contaminated. Moreover, when the polyethylene 21 200813132 alcohol film is dyed and stretched to prepare a polarizing plate, the polarizing plate prepared in the examples 丨 to 3 has a polarization of 99. 8 to 99.9% and no optical contamination. The object appeared, but the polarizing plate prepared in Comparative Example 1 had a degree of polarization of 99 5% (which is lower than the polarization of the polarizing plate of Examples 1-3), and an optical contaminant was observed. It is estimated that the vapor formed in the solution casting step generates contaminants such as dents on the surface of the film layer. Industrial Applicability According to the method of the present invention, when the polyvinyl alcohol aqueous solution is discharged through the τ-type mold for 10 埠 continuous Casting on the surface of the casting drum, the helium gas discharged from the lower surface of the discharge layer is sucked by an airless extraction device, wherein the vapor extraction device is placed in a space between (1) and (ii), (1) It is the lower surface of the discharge layer, the lower surface faces the casting cylinder, and is formed immediately after the discharge of the aqueous solution is discharged, and the extension line of the discharge layer has a direction toward the discharge 15 埠, and its (! i) is the surface of the drum. Therefore, since steaming can be avoided The method for preparing the polyvinyl alcohol film of the present invention can effectively improve the uniformity of the surface of the polyvinyl alcohol film by adhering to the film layer and the surface of the casting tube to generate contaminants. Similarly, the polyvinyl alcohol electrode prepared from the polyvinyl alcohol film is used. The slab (on its large surface) has excellent polarization properties. 20 Embodiments of the present invention are for illustrative purposes, and those skilled in the art may devote themselves to the scope of the original field of the patent of the present invention. Various modifications, additions and substitutions are made in the spirit of the present invention. [Simplified Description of the Drawings] 22 200813132 These and other features, aspects, and advantages of the preferred embodiments of the present invention will be explained in more detail above. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial structural view of an embodiment of a conventional polarizing plate. Figure 2 is a schematic view of a conventional casting machine for preparing a polyvinyl alcohol film. It is a schematic diagram of each machine used in the preparation method of the polyvinyl alcohol film according to an embodiment of the present invention. [Description of main components] 1 polarized plate 21 T-die 2, 3 protective film 22 controls 筏4, 5 Pressure-sensitive adhesive layer 23 Vapor does not take the skirt 7, 8 Protective layer 24 Casting 6 Polarizing plate 25 Discharge layer 9 Adhesive layer. 26 Extension line 10 Polarized layer 23