TW201809758A - Polarizing plate and preparing method for the same - Google Patents

Abstract

The present invention relates to a polarizing plate, and a method of manufacturing the same. More specifically, a rate of moisture of the polarizing plate is 2.8-4.8%, and a thickness of an adhesive layer made of an adhesive composition comprising acetoacetyle-modified polyvinyl alcohol-based resin, glyoxal crosslinking agent, and water-soluble salt of two or more multivalent metal ions is 30-200 nm.

Description

偏光板及其製造方法Polarizing plate and manufacturing method thereof

本發明係關於顯示出優異之耐水性並且能夠防止光特性降低之偏光板及其製造方法。The present invention relates to a polarizing plate that exhibits excellent water resistance and is capable of preventing degradation of light characteristics and a method for producing the same.

偏光板可作為構成液晶顯示裝置之光學部件之一使用。偏光板通常具有在偏光器之兩面層疊了保護膜之結構，且***液晶顯示裝置中。已知亦有僅在偏光器之一面設置保護膜，但多數情況下，在另一面不是單純的保護膜，而是將具有另外功能例如光學功能之層以兼作保護膜之方式接合。 一般使用如下構成之偏光板：使用使碘在聚乙烯醇中吸附取向之碘系膜、使二色性染料在聚乙烯醇中吸附取向之染料系膜作為偏光器，至少在膜之單面經由使用聚乙烯醇系樹脂的水溶液(聚乙烯醇系黏接劑)形成之黏接層將三乙醯纖維素(TAC)等之保護膜接合，但此類構成之偏光板在濕熱下長時間使用時存在保護膜與偏光器之端面容易剝離的問題。 由此提出了如下偏光板：使用聚乙烯醇系黏接劑將偏光器(偏光膜)與保護膜接合後，藉由在80℃至100℃之溫度下加熱乾燥，從而改良耐濕熱性，但在濕熱下長時間使用之情況下，依然沒有解決保護膜與偏光器之端面容易剝離的問題。 為了解決此類問題，專利文獻1中公開了包含乙醯乙醯基改性聚乙烯醇系樹脂、聚乙烯醇系樹脂(交聯調節劑)、乙二醛系(交聯劑)及氯化鋅(交聯催化劑)的黏接劑組合物。但是，在上述組合物之情況下，存在如下問題：由於包含交聯調節劑，因此固化速度慢，從而導致由濕熱劣化引起之偏光度降低。 因此，為了即使在濕熱條件下亦防止保護膜與偏光器之短邊分離，現狀是要求開發耐水性優異、能夠防止由其導致之光特性降低之黏接劑組合物。 現有技術文獻 專利文獻 專利文獻1：日本專利公開第1995-134212號公報The polarizing plate can be used as one of optical components constituting a liquid crystal display device. A polarizing plate generally has a structure in which protective films are laminated on both sides of a polarizer, and is inserted into a liquid crystal display device. It is known that a protective film is provided only on one side of the polarizer. However, in most cases, the protective film is not a simple protective film on the other side, but a layer having another function such as an optical function is also used as a protective film. Generally, a polarizing plate having the following structure is used: an iodine-based film in which iodine is adsorbed and oriented in polyvinyl alcohol, and a dye-based film in which dichroic dye is adsorbed and oriented in polyvinyl alcohol as a polarizer, at least on one side of the film. Adhesive layer formed by using an aqueous solution of polyvinyl alcohol resin (polyvinyl alcohol adhesive) to join protective films such as triethyl cellulose (TAC), but this type of polarizing plate is used for a long time under humid heat In this case, there is a problem that the end faces of the protective film and the polarizer are easily peeled. Thus, a polarizing plate has been proposed in which a polarizer (polarizing film) and a protective film are bonded using a polyvinyl alcohol-based adhesive, and then heated and dried at a temperature of 80 ° C to 100 ° C to improve the heat and humidity resistance. In the case of long-term use under moist heat, the problem of easy peeling of the protective film and the end face of the polarizer has not been solved. In order to solve such problems, Patent Document 1 discloses an acetonitrile-modified polyvinyl alcohol-based resin, a polyvinyl alcohol-based resin (crosslinking regulator), a glyoxal (crosslinking agent), and chlorination. Adhesive composition of zinc (crosslinking catalyst). However, in the case of the above-mentioned composition, there is a problem in that the curing speed is slow because the crosslinking regulator is contained, which leads to a decrease in the degree of polarization due to the damp heat degradation. Therefore, in order to prevent the protective film from being separated from the short side of the polarizer even under humid and hot conditions, the current situation is to develop an adhesive composition that is excellent in water resistance and capable of preventing a reduction in light characteristics caused by it. Prior Art Literature Patent Literature Patent Literature 1: Japanese Patent Publication No. 1995-134212

發明要解決之課題 為了解決上述問題，本發明之目的在於提供顯示優異的耐水性並且能夠防止光特性降低之偏光板及其製造方法。用於解決課題之手段 為了實現上述目的，本發明之偏光板之特徵在於，水分率為2.8%至4.8%，由包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之水溶性鹽的黏接劑組合物形成之黏接劑層之厚度為30 nm 至200 nm。 另外，為了實現上述目的，根據本發明之偏光板之製造方法，其特徵在於，包含：(a)在偏光器之兩面塗佈包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之水溶性鹽的黏接劑組合物，生成黏接劑層之階段；(b)在上述黏接劑層上將至少一個以上之保護膜採用壓料輥接合，製作偏光板之階段；及(c)上述偏光板通過至少2個以上之乾燥通路而被乾燥之階段。發明之效果 根據本發明之偏光板，藉由調節偏光板之水分率及黏接劑層之厚度，從而在不會降低光特性之同時具有提高耐水性之效果。 另外，採用根據本發明之偏光板之製造方法製造的偏光板亦具有上述效果。 Problem to be Solved by the Invention In order to solve the above-mentioned problems, an object of the present invention is to provide a polarizing plate that exhibits excellent water resistance and can prevent degradation of light characteristics, and a method for manufacturing the same. Means for Solving the Problem In order to achieve the above-mentioned object, the polarizing plate of the present invention is characterized by having a moisture content of 2.8% to 4.8%, and containing an ethylene-acetamido-modified polyvinyl alcohol resin and a glyoxal cross-linking agent The thickness of the adhesive layer formed from the adhesive composition of the water-soluble salt of two or more kinds of polyvalent metal ions is 30 nm to 200 nm. In addition, in order to achieve the above-mentioned object, the method of manufacturing a polarizing plate according to the present invention includes: (a) coating both sides of the polarizer with an ethyl acetate-modified polyvinyl alcohol-based resin and glyoxal A cross-linking agent and an adhesive composition of two or more kinds of polyvalent metal ion water-soluble salts to form an adhesive layer; (b) applying at least one protective film on the adhesive layer A stage in which the rolls are bonded to produce a polarizing plate; and (c) a stage in which the polarizing plate is dried through at least two drying paths. Effects of the Invention According to the polarizing plate of the present invention, by adjusting the moisture content of the polarizing plate and the thickness of the adhesive layer, it has the effect of improving water resistance without reducing light characteristics. In addition, the polarizing plate manufactured by the method for manufacturing a polarizing plate according to the present invention also has the above-mentioned effects.

本發明中某部分「包含」某構成要素時，只要無特別地相反之記載，其並不排除其他構成要素，意謂能夠進一步包含其他構成要素。 以下對本發明之較佳之實施方式詳細地說明。〈偏光板〉 根據本發明之一實施方式的偏光板，藉由使水分率為2.8%至4.8%，使由包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之水溶性鹽的黏接劑組合物形成之黏接劑層之厚度成為30 nm至200 nm，從而具有如下之效果：不會相隨有光特性之降低，即使在濕熱條件下亦防止保護膜與偏光器之短邊分離，因此能夠提高耐水性。 上述偏光板之水分率意謂採用如下之重量水分率測定法測定之水分率：對結束了全部之乾燥工序而完成的偏光板在105℃下熱處理2小時前/後之重量變化進行觀察。 本發明中所謂偏光板，可以意謂本領域中所使用之偏光板，作為一例，可以是在偏光器之至少一面上將一個以上之保護膜黏接而成之產物。黏接劑層 就本發明之偏光板而言，藉由包含厚度為30 nm至200 nm、由包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之水溶性鹽的黏接劑組合物形成之黏接劑層，從而不會伴有光特性之降低，即使在濕熱條件下亦防止保護膜與偏光器之短邊分離，因此具有能夠使耐水性提高之效果，在上述黏接劑層之厚度不到30 nm之情況下，可發生外觀上之問題，在超過200 nm之情況下，發生濕熱劣化，可發生光特性降低的問題。 上述黏接劑組合物包含：包含乙醯乙醯基改性聚乙烯醇系樹脂及乙二醛交聯劑的A液以及包含乙醯乙醯基改性聚乙烯醇系樹脂及2種以上之多價金屬離子之水溶性鹽的B液，可將上述A液及B液混合而製造。 上述A液及B液各自所含有之乙醯乙醯基改性聚乙烯醇系樹脂可以與水(蒸餾水)混合而以水溶液之形態將其混合，就上述A液及B液各自所含有之乙醯乙醯基改性聚乙烯醇系樹脂的固體成分之含量而言，相對於上述乙醯乙醯基改性聚乙烯醇系樹脂水溶液100重量%，含有2.5重量%至4.5重量%，從而具有如下效果：不會伴有光特性之降低，即使在濕熱條件下亦防止保護膜與偏光器之短邊分離，因此能夠使耐水性提高。具體地，上述A液及B液各自所含有之乙醯乙醯基改性聚乙烯醇系樹脂之固體成分之含量不到2.5%的情況下，可發生耐水性效果降低的問題，超過4.5%之情況下，可發生光學特性降低之問題。乙醯乙醯基改性聚乙烯醇系樹脂 本發明之黏接劑層中所含之黏接劑組合物藉由包含乙醯乙醯基改性聚乙烯醇系樹脂，能夠使保護膜與偏光器之黏接力提高。 上述乙醯乙醯基改性聚乙烯醇系樹脂與羧基改性、羥甲基改性、氨基改性等此類之改性之聚乙烯醇樹脂相比，含有反應性高之官能團，在耐久性之提高態樣優異。 上述乙醯乙醯基改性聚乙烯醇系樹脂藉由採用公知之方法使聚乙烯醇系樹脂與二烯酮(diketene)反應而得到。具體地，採用使聚乙烯醇系樹脂在醋酸等溶劑中分散後向其中添加二烯酮之方法；使聚乙烯醇系樹脂預先溶解於二甲基甲醯胺或二噁烷等溶劑中後向其中添加二烯酮之方法；或者使聚乙烯醇系樹脂與二烯酮氣體或液體二烯酮直接接觸之方法等得到。 上述乙醯乙醯基改性聚乙烯醇系樹脂只要乙醯乙醯基改性度為0.1莫耳%以上，則並無特別限制，較佳為0.1莫耳%至40莫耳%，更佳為1莫耳%至20莫耳%，最佳為2莫耳%至7莫耳%。上述乙醯乙醯基之改性度不到0.1莫耳%之情況下，由於黏接劑層之耐水性不充分而不適合，上述乙醯乙醯基之改性度超過40莫耳%的情況下，耐水性之提高效果極低。 對上述乙醯乙醯基改性聚乙烯醇系樹脂之皂化度並無特別限制，較佳為80莫耳%以上，另外，更佳為85莫耳%以上。上述乙醯乙醯基改性聚乙烯醇系樹脂之皂化度不到上述範圍的情況下，難以顯現出充分之水溶性，因此可產生黏接性降低之問題。 上述乙醯乙醯基改性聚乙烯醇系樹脂之聚合度較佳在100至1500內。上述乙醯乙醯基改性聚乙烯醇系樹脂之聚合度為上述範圍內之情況下，具有使偏光板中之偏光器與保護膜間之黏接力提高的效果。 上述乙醯乙醯基改性聚乙烯醇系樹脂具體地可列舉出Z-100、Z-200、Z-200H、Z-210、Z-220及Z-320(日本合成化學Gohsefimer株式會社)等，但並不限定於此。乙二醛交聯劑 本發明之黏接劑層中所含之黏接劑組合物包含乙二醛交聯劑。 含有上述乙二醛系交聯劑之情況下，藉由上述乙二醛系交聯劑內之醛基不僅與上述乙醯乙醯基改性聚乙烯醇系樹脂而且與偏光器、保護膜內所含之羥基進行縮合反應，從而使黏接劑組合物之交聯度提高，具有使利用其接合之偏光器與保護膜間之黏接力及耐水性提高的效果。 就上述乙二醛系交聯劑之含量而言，相對於在上述A液中一起含有之乙醯乙醯基改性聚乙烯醇系樹脂之固體成分100重量份，能夠以30重量份至70重量份含有乙二醛系交聯劑。上述乙二醛系交聯劑之含量不到上述範圍之情況下，可發生由包含上述乙二醛系交聯劑之黏接劑組合物形成之黏接劑層之耐水性降低的問題，超過上述範圍之情況下，可產生調液穩定性降低之問題。多價金屬離子之水溶性鹽 本發明之黏接劑層中所含之黏接劑組合物藉由包含2種以上之多價金屬離子之水溶性鹽，從而不僅促進上述乙二醛系交聯劑之效果，使包含其之黏接劑組合物之交聯度提高，而且具有使利用其所黏接之偏光器與保護膜間之交聯度提高的效果。由此具有如下效果：能夠提高上述黏接劑層之黏接力及耐水性，亦能夠防止與其相伴之光學耐久性的降低。 上述多價金屬離子之水溶性鹽具體地可自氯化鋅、氯化鈷、氯化鎂、醋酸鎂、硝酸鋁、硝酸鋅及硫酸鋅中選擇，更佳自交聯催化劑之作用優異的氯化鋅、硝酸鋅及硝酸鋁中選擇。 上述多價金屬離子之水溶性鹽包含氯化鋅之情況下，就其含量而言，相對於上述B液中一起含有之乙醯乙醯基改性聚乙烯醇系樹脂之固體成分100重量份，能夠以2重量份至10重量份含有。在上述氯化鋅之含量不到上述範圍之情況下，可產生由包含上述氯化鋅之黏接劑組合物形成之黏接劑層之耐水性不充分的問題，超過上述範圍之情況下，可產生調液穩定性降低之問題。 上述多價金屬離子之水溶性鹽包含硝酸鋅或硝酸鋁之情況下，相對於上述B液中所含之乙醯乙醯基改性聚乙烯醇系樹脂的固體成分100重量份，其含量能夠為30重量份至90重量份。上述硝酸鋅或硝酸鋁之含量不到上述範圍之情況下，可發生由包含上述硝酸鋅或硝酸鋁之黏接劑組合物形成的黏接劑層之耐水性不充分之問題，超過上述範圍之情況下，可發生調液穩定性降低之問題。 本發明之黏接劑層中所含之黏接劑組合物之20℃下之黏度較佳為3 mPa・sec至25 mPa・sec範圍內。黏接劑組合物之黏度不到3mPa・sec之情況下，不能充分地顯現由上述黏接劑組合物形成之黏接劑層的耐水性，黏度超過25 mPa・sec 之情況下，存在包含上述黏接劑層之偏光板之光學特性降低的問題。 上述黏接劑組合物在不阻礙本發明之效果的範圍內，能夠進一步包含增塑劑、矽烷偶聯劑、抗靜電劑、微粒、使擴展性變得良好之醇、流平劑等添加劑。 對上述黏接劑組合物之形態並無特別限制，為了在作為被附著體之偏光器及保護膜之表面形成均一的黏接劑層，較佳為液型。作為此類之液型之黏接劑，能夠使用各種溶劑之溶液型或分散液型，若考慮基材之塗佈性態樣，較佳溶液型，如果考慮穩定性態樣，則較佳以水作為溶劑之溶液型或分散液型。偏光器 ( 偏光膜 ) 用於形成偏光器之聚乙烯醇系樹脂藉由將聚醋酸乙烯酯系樹脂皂化而得到。作為聚醋酸乙烯酯系樹脂，除了作為醋酸乙烯酯之均聚物的聚醋酸乙烯酯以外，可列舉出醋酸乙烯酯與可與其共聚之其他單體之共聚物等。作為與醋酸乙烯酯共聚之其他單體，例如可列舉出不飽和羧酸類、不飽和磺酸類、烯烴類、乙烯基醚類、具有銨基之丙烯醯胺類等。聚乙烯醇系樹脂之皂化度通常為85莫耳%至100莫耳%，較佳為98莫耳%以上。可對該聚乙烯醇系樹脂進一步改性，例如亦能夠使用用醛類改性了之聚乙烯醇聚合物、聚乙烯醇縮醛等。構成偏光器之聚乙烯醇系樹脂之平均聚合度通常為1000至10000，較佳為1500至5000。 將此類之聚乙烯醇系樹脂在膜上製膜而成之產物(聚乙烯醇系樹脂膜)用於偏光器之原版膜。對聚乙烯醇系樹脂進行製膜之方法並無特別限定，能夠採用公知之製膜方法。成為原版之聚乙烯醇系樹脂膜之膜厚並無特別限定，例如能夠為10 μm 至50 μm。 偏光器通常可採用如下方法製造，該方法包含：對此類之成為原版之聚乙烯醇系樹脂膜進行單軸拉伸之工序、用二色性色素對聚乙烯醇系樹脂膜進行染色並使該二色性色素吸附之工序、對吸附了二色性色素之聚乙烯醇系樹脂膜用硼酸水溶液進行處理的工序及在採用該硼酸水溶液之處理後進行水洗的工序。 單軸拉伸可在染色前進行，亦可與染色同時地進行，亦可在染色後進行。在染色後進行單軸拉伸之情況下，可在硼酸處理前進行單軸拉伸，亦可在硼酸處理中進行，亦可在硼酸處理後進行。當然，亦可以通過其的多個步驟進行單軸拉伸。單軸拉伸中，可在不同之輥間對原版膜進行單軸拉伸，亦可利用熱輥進行單軸拉伸。另外，可以是在大氣中進行拉伸等之乾式拉伸，亦可以是在用溶劑溶脹之狀態下進行拉伸之濕式拉伸。拉伸倍率通常為3倍至8倍。 為了用二色性色素對聚乙烯醇系樹脂膜進行染色，例如能夠將聚乙烯醇系樹脂膜浸漬於含有二色性色素之水溶液中。作為二色性色素，具體地，可使用碘或二色性染料。另外，聚乙烯醇系樹脂膜較佳在染色處理前在水中進行浸漬處理。 使用碘作為二色性色素之情況下，通常採用將聚乙烯醇系樹脂膜浸漬於含有碘及碘化鉀之水溶液中進行染色之方法。該水溶液中之碘的含量通常為每100重量份水0.01重量份至1重量份，碘化鉀之含量通常為每100重量份水0.5重量份至20重量份。染色中使用之水溶液的溫度通常為20℃至40℃，另外，在該水溶液中之浸漬時間通常為20秒至1800秒。 使用二色性染料作為二色性色素之情況下，通常採用將聚乙烯醇系樹脂膜浸漬於包含水溶性二色性染料之水溶液中進行染色之方法。就該水溶液中之二色性染料之含量而言，相對於水100重量份，通常為1×10^-4 重量份至10重量份，較佳為1×10^-3 重量份至1重量份。該水溶液亦能夠含有硫酸鈉等無機鹽作為染色輔助劑。在染色中利用之染料水溶液之溫度通常為20℃至80℃，另外，對於該水溶液之浸漬時間通常為10秒至1800秒。 採用二色性色素之染色後之硼酸處理通過將經染色之聚乙烯醇系樹脂膜浸漬於含有硼酸的水溶液中而進行。就含有硼酸之水溶液中之硼酸的量而言，相對於水100重量份，通常為2重量份至15重量份，較佳為5重量份至12重量份。使用碘作為二色性色素之情況下，該含有硼酸之水溶液較佳含有碘化鉀。就含有硼酸之水溶液中之碘化鉀之量而言，相對於水100重量份，通常為0.1重量份至15重量份，較佳為5重量份至12重量份。在含有硼酸之水溶液中之浸漬時間通常為60秒至1200秒，較佳為150秒至600秒，更較佳為200秒至400秒。含有硼酸之水溶液的溫度通常為50℃以上，較佳為50℃至85℃，更較佳為60℃至80℃。 對硼酸處理後之聚乙烯醇系樹脂膜通常進行水洗處理。水洗處理例如藉由將經硼酸處理之聚乙烯醇系樹脂膜浸漬於水中而進行。水洗處理中之水的溫度通常為5℃至40℃，浸漬時間通常為1秒至120秒。在水洗後實施乾燥處理，得到偏光器。乾燥處理通常利用熱風乾燥機、遠紅外線加熱器進行。乾燥處理之溫度通常為30℃至100℃，較佳為50℃至80℃。乾燥處理之時間通常為60秒至600秒，較佳為120秒至600秒。 如此對聚乙烯醇系樹脂膜進行單軸拉伸、採用二色性色素之染色及硼酸處理，得到偏光器。該偏光器之厚度通常為5 μm至40 μm之範圍內，較佳為10 μm至35 μm之範圍內。保護膜 上述保護膜具體地能夠使用纖維素系樹脂膜、環烯烴系樹脂膜、丙烯酸系樹脂膜、聚酯系樹脂膜等各種透明樹脂膜。 使用纖維素系樹脂膜作為上述保護膜之情況下，較佳為纖維素之至少一部分被酯化的醋酸纖維素系樹脂。例如可列舉出三乙醯纖維素、二乙醯纖維素、乙酸丙酸纖維素等。 上述環烯烴系樹脂為例如具有降冰片烯、多環降冰片烯系單體此類之環烯烴之單體單元之熱塑性的樹脂，可以是上述環烯烴之開環聚合物、利用了2種以上之環烯烴之開環共聚物的氫化物，亦可以是環烯烴與鏈狀烯烴、具有乙烯基之芳香族化合物之加成共聚物。另外，可在環烯烴系樹脂中引入了極性基團。 對利用了黏接劑組合物之偏光器與保護膜之接合方法並無特別限定，例如可列舉出如下之方法：採用流延法、繞線棒塗佈法、凹版塗佈法、模壓塗佈法、浸漬塗佈法、噴霧法等將黏接劑組合物塗佈於偏光器及/或保護膜之黏接面，使兩者重疊。上述流延法是邊使作為被塗佈物之偏光器或保護膜在大致垂直方向、大致水平方向或兩者間之傾斜方向上移動，邊將黏接劑組合物塗佈於其表面之方法。 將上述黏接劑組合物塗佈後，通過用壓料輥(nip roll)夾持偏光器與保護膜而使其接合。 另外，為了提高黏接性，亦能夠適當地對偏光器及/或保護膜之表面進行等離子體處理、電暈處理、紫外線照射處理、火焰處理、皂化處理等表面處理。作為上述皂化處理，可列舉出浸漬於氫氧化鈉、氫氧化鉀等之鹼水溶液中之方法。 將偏光器與保護膜層疊後，實施乾燥處理。乾燥處理例如藉由將熱風噴霧而進行，此時的溫度在50℃至100℃範圍中適當地選擇。乾燥時間通常為30秒至1000秒。〈偏光板之製造方法〉 本發明之另一實施方式為製造上述之偏光板的方法，其特徵在於，包含：(a)在偏光器之兩面塗佈包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之水溶性鹽的黏接劑組合物，生成黏接劑層之階段；(b)在上述黏接劑層上利用壓料輥將至少一個以上之保護膜接合，製作偏光板之階段；(c)上述偏光板通過至少2個以上之乾燥通路，進行乾燥之階段。採用此類之方法可以使偏光板之水分率成為2.8%至4.8%，將偏光板中所含之黏接劑層之厚度調節至30 nm至200 nm。因此，能夠製造具有如下效果之偏光板：不會伴有光特性之降低，即使在濕熱條件下亦防止保護膜與偏光器之短邊分離，因此能夠使耐水性提高。 對於本發明之偏光板製造方法，以下只要無另外之記載，偏光板之構成要素能夠使用上述之偏光板的構成要素。 在上述(b)階段中，壓料輥是在偏光器之至少一面上使保護膜黏接之機械，在偏光器、保護膜之上下面的方向上可分別存在至少1個以上之壓料輥，位於上述偏光器、保護膜之上下面之壓料輥藉由對通過其之間的偏光器及保護膜施加壓力，從而可將保護膜黏接於偏光器。 為了上述偏光器與保護膜間之黏接而施加之壓料輥的壓力即壓料壓力可以為0.3 MPa至0.9 MPa，上述壓料壓力不到上述範圍之情況下，偏光器與保護膜間之黏接劑層超過作為本發明之構成的200 nm，發生濕熱劣化，光特性降低，上述壓料壓力超過上述範圍之情況下，黏接劑層不到作為本發明之構成的30 nm，可發生外觀不良。 與通過壓料輥之偏光器、保護膜之上面接觸之壓料輥上的一部分面及與上述偏光器、保護膜之下面接觸之壓料輥上之一部分面之間隔即壓料間隙(nip gap)能夠為-1500 μm至-500 μm。上述壓料間隙不到上述範圍之情況下，上述黏接劑層之厚度不到作為本發明之構成的30 nm，可發生外觀不良，超過上述範圍之情況下，上述黏接劑層之厚度超過作為本發明之構成的200 nm，發生濕熱劣化，可發生光特性降低之問題。此時，為了測定上述壓料間隙所使用之位於偏光器、保護膜之上下面之壓料輥設為相互最為接近的壓料輥。 在上述(b)階段中利用壓料輥將在偏光器之至少一面上黏接了之保護膜接合而成之偏光板在上述(c)階段中可通過至少2個以上之乾燥通路而被乾燥，本發明中，為了方便起見，按偏光板通過之順序將多個乾燥通路命名為第1乾燥通路、第2乾燥通路、第3乾燥通路等。上述乾燥通路能夠使用熱風，偏光板通過至少2個以上之乾燥通路時，較佳後續階段之乾燥通路內之熱風之溫度比前一階段之乾燥通路內之熱風的溫度高。例如，第2乾燥通路內之熱風之溫度比第1乾燥通路內之熱風的溫度高。更具體地，第1乾燥通路內之熱風之溫度較佳為50℃以下，多個乾燥通路中最後的乾燥通路內之熱風之溫度較佳為80℃以上。上述第1乾燥通路內之溫度超過50℃的情況下，由於急劇之水分蒸發而發生濕熱劣化，光特性降低，最後的乾燥通路內之熱風之溫度不到80℃之情況下，偏光板之水分率升高，可發生光學特性經時地降低之問題。〈影像顯示裝置〉 本發明之另一方案為具備上述之偏光板的影像顯示裝置。 本發明之影像顯示裝置具備上述偏光板，如果舉出具體之例子，可列舉出液晶顯示器、OLED、撓性顯示器等，但並不限定於此。 以下為了有助於本發明之理解，提出較佳之實施例，以下實施例只不過是對本發明進行例示，在本發明之範疇及技術思想之範疇內可進行多種改變及修正，此對於熟習此項技術者而言是清楚的，此類之變形及修正屬於所附之專利申請專利範圍，此亦是當然的。在以下之實施例及比較例中，表示含量之“%”及“份”只要無特別說明則為重量基準。製造例 製造例 1. 偏光器之製造 將平均聚合度為2400、皂化度為99.9莫耳%以上之75 μm厚之聚乙烯醇膜以乾式單軸拉伸約5倍，在維持拉伸狀態下，在60℃之水(蒸餾水)中浸漬1分鐘後，用碘/碘化鉀/蒸餾水之重量比為0.05/5/100之28℃的水溶液浸漬了60秒。然後，在碘化鉀/硼酸/蒸餾水之重量比為8.5/8.5/100之72℃水溶液中浸漬300秒，用26℃之蒸餾水清洗20秒後，在65℃下乾燥，製造了使碘在PVA系膜吸附取向之偏光器。製造例 2. 保護膜之製造 將作為三乙醯纖維素系膜之KC8UX (柯尼卡公司、T)皂化而使用。製造例 3. 黏接劑 組合物之製造 A液組合物之製造：在水(蒸餾水)中溶解皂化度為99.2莫耳%之乙醯乙醯基改性聚乙烯醇系樹脂(ゴーセノールZ200、日本合成化學工業株式會社)，製造固體成分之含量如表1所示的水溶液。在上述水溶液中以表1中記載之含量追加了乙二醛交聯劑40%水溶液(大井化金)後，混合，製造了黏接劑A液組合物。 B液組合物之製造：在水(蒸餾水)中溶解皂化度為99.2莫耳%之乙醯乙醯基改性聚乙烯醇系樹脂(ゴーセノールZ200、日本合成化學工業株式會社)，製造了固體成分之含量如表1所示的水溶液。在上述水溶液中以表1中記載之含量追加作為多價金屬離子之水溶性鹽之氯化鋅(大井化金)及硝酸鋅(大井化金)後混合，製造了黏接劑B液組合物。 將上述製造之A液組合物及B液組合物在常溫下混合，攪拌約30分鐘，製造了黏接劑組合物。實施例 1 至實施例 8 及比較例 1 至比較例 7 ：偏光板之製造 在上述製造例1中製造之偏光器之兩面以表1中記載之含量塗佈了利用上述製造例3之方法製造之黏接劑組合物後，利用壓料輥使上述製造例2之保護膜接合。此時，工序條件(壓料壓力、壓料間隙)如表1所示那樣，利用壓料輥接合之偏光板利用乾燥通路內之熱風乾燥機乾燥。用總共5個階段進行乾燥過程，第1乾燥通路內之熱風之溫度及第5乾燥通路內之熱風之溫度如表1所示一般，此外，第2乾燥通路內之熱風之溫度為50℃，第3乾燥通路內之熱風的溫度為70℃，第4乾燥通路內之熱風之溫度為75℃，在各乾燥通路內乾燥5分鐘，最終製造了偏光板。測定如此製造之偏光板之水分率及上述偏光板中所含之黏接劑層的厚度，一起記載於表1中。 此時，上述偏光板之水分率採用對在105℃下進行了2小時之熱處理之前/後之重量變化進行觀察的重量水分率測定法測定。 [表1] 實驗例 實驗例 1. 黏 接力評價 ( 切削刀具評價 ) 將上述製造之偏光板在常溫下放置了1小時後，在偏光板之各膜間(偏光器與偏光器保護膜之間)放入切削刀具之刃，按照以下之標準評價將刃推進時之刃進入的方式，將其結果示於表2中。 ◎：切削刀具之刃未進入所有的膜間。 ○：將刃推進時，在至少任一個之膜間，刃在進入了1 mm至2 mm時停住。 △：將刃推進時，在至少任一個之膜間，刃在進入了3 mm至5 mm時停住。 ×：將刃推進時，在至少任一個之膜間，刃容易地進入。實驗例 2. 耐水性評價 對於在23℃、相對濕度55%之環境下放置了24小時之各偏光板，採用以下所述之方法進行耐溫水性實驗，評價了耐水性。 將偏光板之吸收軸作為長邊，將偏光板切斷為5 cm×2 cm之大小而製成樣品，正確地測定了其長邊方向之尺寸。此時，上述樣品由於吸附於偏光膜之碘，而全面地均一地顯示出特有之顏色。圖1為示意地表示耐水性之評價方法之圖，(A)表示溫水浸漬前之樣品1，(B)表示溫水浸漬後之樣品1。如圖1(A)中所示一般，將樣品之一短邊側用把持具5把持，將長度方向之80%左右浸漬於60℃之水槽中，維持了8小時。然後，將樣品1從水槽中取出，擦除水分。 藉由上述此類之溫水浸漬，偏光板之偏光器4收縮。藉由測定自樣品1之短邊之中央處之末端部1a (保護膜之終端)至收縮之偏光器4之端部之距離來評價上述偏光器4之收縮程度，設為收縮長度。另外，如圖1(B)中所示那樣，藉由溫水浸漬，使位於偏光板之中央之偏光器4收縮，從而在保護膜2之間碘從偏光器4之周緣部溶出，在樣品1之周緣部產生脫色之部分3。藉由測定從樣品1之短邊的中央處之收縮的偏光器4之末端部至殘留有偏光板特有之顏色之區域的距離來評價此類之脫色程度，設為碘脫色之長度。將上述收縮長度與碘脫色之長度之和設為總浸蝕長度x。總浸蝕長度x為自樣品1之短邊之中央處的樣品1之端部1a至偏光板特有之顏色殘留之區域的距離。收縮長度、碘之脫色長度及總浸蝕長度x越小，能夠判斷水之存在下之黏接性越高。根據總浸蝕長度x，用以下之4等級評價，將其結果記載於表2中。 ◎：總浸蝕長度x不到0.1 mm ○：總浸蝕長度x為0.1 mm以上且不到0.5 mm △：總浸蝕長度x為0.5 mm以上且不到2 mm ×：總浸蝕長度x為2 mm以上實驗例 3. 透射率、偏光度 (%) 將製造之偏光板切斷為4 cm×4 cm之大小，製作試驗片，使該試驗片附著於測定支架後，利用紫外可見光線分光計(V-7100、JASCO Corporation製造)測定，將其結果記載於表2中。 [表2] 參照表2，確認了在乙醯乙醯基改性聚乙烯醇系樹脂之水溶液內之固體成分的含量不到本發明之較佳範圍(2.5重量%至4.5重量%)之情況下(比較例1)，與滿足本發明之較佳之範圍的情形(實施例1至8)相比，偏光板之水分率不足，耐水性差，在超過上述範圍之情況下(比較例2)，偏光板之水分率增加，偏光板中所含之黏接劑層之厚度變厚，發生光特性降低之問題。另外確認，本發明之偏光板的工序條件(壓料壓力、壓料間隙)脫離本發明之範疇的情況下(比較例3至4)，製造脫離本發明中所要求之偏光板之水分率、偏光板中所含之黏接劑層之厚度範圍的偏光板，由此，確認了耐水性、光特性降低。在偏光板之乾燥過程中第1乾燥通路內之熱風的溫度超過本發明之溫度範圍(50℃以下)之情況下(實施例7)，能夠滿足本發明中所要求之偏光板之水分率及偏光板中所含之黏接劑層之厚度範圍，但與滿足上述溫度範圍的(實施例1至6及8)之情形相比，產生光特性略有降低之問題，對於第5乾燥通路內之熱風之溫度範圍，在脫離本發明之溫度範圍(80℃以上)之情況下(比較例5)，確認了超過本發明中所要求之偏光板的水分率，出現了耐水性及光特性之降低。另外，只使用1種多價金屬離子之水溶性鹽之情況下(比較例6及7)，確認了耐水性降低。When a certain part of the present invention “contains” a certain constituent element, as long as there is no particularly contrary description, it does not exclude other constituent elements, which means that other constituent elements can be further included. Hereinafter, preferred embodiments of the present invention will be described in detail. <Polarizing Plate> According to a polarizing plate according to an embodiment of the present invention, an acetonitrile-modified polyvinyl alcohol-based resin, a glyoxal cross-linking agent, and The thickness of the adhesive layer formed by the adhesive composition of the water-soluble salt of two or more kinds of polyvalent metal ions is 30 nm to 200 nm, so that it has the following effect: it does not follow the degradation of the light characteristics, even if The protective film is also prevented from separating from the short side of the polarizer under humid and hot conditions, so that water resistance can be improved. The moisture content of the above-mentioned polarizing plate means a moisture content measured by a weight moisture content measuring method: observing a change in weight of the polarizing plate before and after heat treatment at 105 ° C. for 2 hours after completing all drying processes. The so-called polarizing plate in the present invention may mean a polarizing plate used in the art. As an example, it may be a product obtained by bonding more than one protective film on at least one side of a polarizer. The adhesive layer of the polarizing plate of the present invention includes a thickness of 30 nm to 200 nm, a modified polyvinyl alcohol-based resin containing acetamidine, a glyoxal cross-linking agent, and two or more kinds. The adhesive layer formed by the adhesive composition of a water-soluble salt of a polyvalent metal ion is not accompanied by a reduction in light characteristics, and prevents the protective film from being separated from the short side of the polarizer even under moist heat conditions. It can improve the water resistance. When the thickness of the adhesive layer is less than 30 nm, appearance problems may occur. When it exceeds 200 nm, moisture and heat degradation may occur, and the light characteristics may decrease. . The above-mentioned adhesive composition includes: liquid A containing acetamethylene acetate modified polyvinyl alcohol resin and glyoxal cross-linking agent; acetamethylene acetate modified polyvinyl alcohol resin and two or more kinds The B liquid of a water-soluble salt of a polyvalent metal ion can be produced by mixing the A liquid and the B liquid described above. The ethyl acetoacetate-modified polyvinyl alcohol resin contained in each of the A liquid and the B liquid may be mixed with water (distilled water) and mixed in the form of an aqueous solution. The content of the solid content of the acetofluorene-modified polyvinyl alcohol-based resin is from 2.5% to 4.5% by weight based on 100% by weight of the above-mentioned acetic acid ethylenically modified polyvinyl alcohol-based resin aqueous solution. The effect is that the protective film is prevented from being separated from the short side of the polarizer even under moist heat conditions without being accompanied by a reduction in light characteristics, so that water resistance can be improved. Specifically, when the solid content of the acetoacetate-modified polyvinyl alcohol-based resin contained in each of the above-mentioned liquids A and B is less than 2.5%, the problem of lowering the water resistance effect may occur, exceeding 4.5%. In this case, a problem that the optical characteristics are reduced may occur. Acetylacetamyl-modified polyvinyl alcohol-based resin The adhesive composition contained in the adhesive layer of the present invention can contain a protective film and polarized light by including an ethylacetamyl-modified polyvinyl alcohol resin. The adhesive force of the device is improved. Compared with modified polyvinyl alcohol resins such as carboxyl-modified, methylol-modified, amino-modified, etc., the above-mentioned acetoacetate-modified polyvinyl alcohol-based resins contain highly reactive functional groups and are durable. Improved appearance is excellent. The said acetoacetic acid modified polyvinyl alcohol-type resin is obtained by making a polyvinyl alcohol-type resin and diketene react by a well-known method. Specifically, a method is used in which polyvinyl alcohol-based resin is dispersed in a solvent such as acetic acid, and dienone is added thereto; the polyvinyl alcohol-based resin is previously dissolved in a solvent such as dimethylformamide or dioxane, and then A method of adding diketene; or a method of directly contacting a polyvinyl alcohol resin with a diketene gas or a liquid diketene. The above-mentioned ethyl acetoacetate-modified polyvinyl alcohol-based resin is not particularly limited as long as the degree of modification of the ethyl acetoacetate group is 0.1 mol% or more, preferably 0.1 to 40 mol%, more preferably It is 1 to 20 mol%, preferably 2 to 7 mol%. In the case where the degree of modification of the above ethyl acetamidine group is less than 0.1 mol%, because the water resistance of the adhesive layer is insufficient, it is not suitable. The effect of improving water resistance is extremely low. There is no particular limitation on the saponification degree of the above-mentioned acetoacetic acid modified polyvinyl alcohol resin, and it is preferably 80 mol% or more, and more preferably 85 mol% or more. When the degree of saponification of the above-mentioned ethyl acetoacetate-modified polyvinyl alcohol-based resin is less than the above range, it is difficult to exhibit sufficient water solubility, and thus a problem of reduced adhesion may occur. The degree of polymerization of the above-mentioned ethyl acetoacetate-modified polyvinyl alcohol-based resin is preferably within a range of 100 to 1500. When the degree of polymerization of the ethyl acetoacetate-modified polyvinyl alcohol-based resin is within the above range, there is an effect that the adhesion between the polarizer and the protective film in the polarizing plate is improved. Specific examples of the above-mentioned acetofluorene-modified polyvinyl alcohol-based resin include Z-100, Z-200, Z-200H, Z-210, Z-220, and Z-320 (Nippon Synthetic Chemical Gohsefimer Co., Ltd.), etc. , But not limited to this. Glyoxal crosslinker The adhesive composition contained in the adhesive layer of the present invention contains a glyoxal crosslinker. When the glyoxal-based cross-linking agent is contained, the aldehyde group in the glyoxal-based cross-linking agent is used not only with the above-mentioned ethyl acetofluorene-modified polyvinyl alcohol-based resin but also in a polarizer and a protective film. The contained hydroxyl group undergoes a condensation reaction, thereby increasing the degree of cross-linking of the adhesive composition, and has the effect of improving the adhesive force and water resistance between the polarizer and the protective film bonded by the adhesive composition. The content of the glyoxal-based cross-linking agent can be 30 to 70 parts by weight based on 100 parts by weight of the solid content of the ethyl acetate-modified polyvinyl alcohol resin contained in the A solution. A part by weight contains a glyoxal-based crosslinking agent. When the content of the glyoxal-based cross-linking agent is less than the above range, a problem may occur in that the water resistance of the adhesive layer formed from the adhesive composition containing the glyoxal-based cross-linking agent is lowered. In the case of the above-mentioned range, there may arise a problem that the stability of the liquid-regulation is lowered. Water-soluble salts of polyvalent metal ions The adhesive composition contained in the adhesive layer of the present invention promotes not only the above-mentioned glyoxal-based cross-linking by including a water-soluble salt of two or more kinds of polyvalent metal ions. The effect of the agent improves the degree of cross-linking of the adhesive composition containing the same, and has the effect of increasing the degree of cross-linking between the polarizer and the protective film to which it is adhered. This has the effect that the adhesive force and water resistance of the above-mentioned adhesive layer can be improved, and a reduction in the optical durability accompanying the same can be prevented. The water-soluble salts of the above-mentioned polyvalent metal ions can be specifically selected from zinc chloride, cobalt chloride, magnesium chloride, magnesium acetate, aluminum nitrate, zinc nitrate, and zinc sulfate. Zinc chloride is more excellent in self-crosslinking catalyst. , Zinc nitrate and aluminum nitrate. In the case where the water-soluble salt of the polyvalent metal ion contains zinc chloride, the content is 100 parts by weight based on 100 parts by weight of the solid content of the ethyl acetofluorene-modified polyvinyl alcohol resin contained in the B liquid. It can be contained in an amount of 2 to 10 parts by weight. In the case where the content of the zinc chloride is less than the above range, the problem of insufficient water resistance of the adhesive layer formed from the adhesive composition containing the above zinc chloride may occur. When the content exceeds the above range, It may cause the problem of lowered liquid stability. In the case where the water-soluble salt of the polyvalent metal ion contains zinc nitrate or aluminum nitrate, the content of the water-soluble salt of the polyvalent metal ion can be 100 parts by weight based on 100 parts by weight of the solid content of the ethyl acetofluorene-modified polyvinyl alcohol resin contained in the liquid B It is 30 parts by weight to 90 parts by weight. When the content of the zinc nitrate or aluminum nitrate is less than the above range, the problem of insufficient water resistance of the adhesive layer formed from the adhesive composition containing the above zinc nitrate or aluminum nitrate may occur. In some cases, the problem of lowering the stability of liquid adjustment may occur. The viscosity at 20 ° C. of the adhesive composition contained in the adhesive layer of the present invention is preferably in a range of 3 mPa · sec to 25 mPa · sec. When the viscosity of the adhesive composition is less than 3 mPa · sec, the water resistance of the adhesive layer formed by the above-mentioned adhesive composition cannot be sufficiently developed. When the viscosity exceeds 25 mPa · sec, the above-mentioned composition may be included. The optical characteristics of the polarizing plate of the adhesive layer are reduced. The said adhesive composition can further contain additives, such as a plasticizer, a silane coupling agent, an antistatic agent, a fine particle, alcohol, a leveling agent, etc. which are good in the range which does not inhibit the effect of this invention. The form of the above-mentioned adhesive composition is not particularly limited. In order to form a uniform adhesive layer on the surface of the polarizer and the protective film as an adherend, a liquid type is preferred. As such a liquid type adhesive, a solution type or a dispersion type of various solvents can be used. If the coating property of the substrate is considered, the solution type is preferred, and if the stability state is considered, it is preferably used. Solution type or dispersion type with water as solvent. Polarizer ( Polarizing Film ) A polyvinyl alcohol-based resin used to form a polarizer is obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group. The saponification degree of the polyvinyl alcohol-based resin is usually 85 mol% to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol-based resin can be further modified. For example, a polyvinyl alcohol polymer modified with an aldehyde, a polyvinyl acetal, or the like can be used. The average degree of polymerization of the polyvinyl alcohol-based resin constituting the polarizer is usually 1,000 to 10,000, preferably 1500 to 5000. The product obtained by forming such a polyvinyl alcohol-based resin on a film (polyvinyl alcohol-based resin film) is used as an original film of a polarizer. The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, A well-known film-forming method can be used. The film thickness of the original polyvinyl alcohol-based resin film is not particularly limited, and it can be, for example, 10 μm to 50 μm. A polarizer can be generally manufactured by a method including a step of uniaxially stretching such a polyvinyl alcohol-based resin film as an original plate, dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and The step of adsorbing a dichroic dye, the step of treating a polyvinyl alcohol-based resin film having adsorbed the dichroic dye with a boric acid aqueous solution, and the step of washing with water after the treatment using the boric acid aqueous solution. Uniaxial stretching may be performed before dyeing, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, uniaxial stretching may be performed before the boric acid treatment, or it may be performed during the boric acid treatment, or it may be performed after the boric acid treatment. Of course, uniaxial stretching can also be performed through multiple steps. In uniaxial stretching, the original film can be uniaxially stretched between different rolls, and it can also be uniaxially stretched using hot rolls. In addition, dry stretching such as stretching in the air may be used, or wet stretching may be performed while swelling with a solvent. The stretching ratio is usually 3 to 8 times. In order to dye a polyvinyl alcohol-type resin film with a dichroic dye, for example, a polyvinyl alcohol-type resin film can be immersed in the aqueous solution containing a dichroic dye. As the dichroic dye, specifically, iodine or a dichroic dye can be used. The polyvinyl alcohol-based resin film is preferably subjected to a dipping treatment in water before the dyeing treatment. When iodine is used as a dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is generally adopted. The content of iodine in the aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually 20 ° C to 40 ° C, and the immersion time in the aqueous solution is usually 20 seconds to 1800 seconds. When a dichroic dye is used as the dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is generally adopted. The content of the dichroic dye in the aqueous solution is usually 1 × 10 ^-4 to 10 parts by weight, and preferably 1 × 10 ^-3 to 1 part by weight, based on 100 parts by weight of water. This aqueous solution can also contain inorganic salts, such as sodium sulfate, as a dyeing adjuvant. The temperature of the aqueous dye solution used in the dyeing is usually 20 ° C to 80 ° C, and the immersion time for the aqueous solution is usually 10 seconds to 1800 seconds. The boric acid treatment after dyeing with a dichroic pigment is performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid. The amount of boric acid in the boric acid-containing aqueous solution is usually 2 to 15 parts by weight, and preferably 5 to 12 parts by weight relative to 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by weight, and preferably 5 to 12 parts by weight relative to 100 parts by weight of water. The immersion time in an aqueous solution containing boric acid is usually 60 seconds to 1200 seconds, preferably 150 seconds to 600 seconds, and more preferably 200 seconds to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50 ° C or higher, preferably 50 ° C to 85 ° C, and more preferably 60 ° C to 80 ° C. The polyvinyl alcohol-based resin film after the boric acid treatment is usually subjected to a water washing treatment. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is usually 5 ° C to 40 ° C, and the immersion time is usually 1 second to 120 seconds. After washing with water, a drying process was performed to obtain a polarizer. The drying process is usually performed using a hot-air dryer and a far-infrared heater. The temperature of the drying treatment is usually 30 ° C to 100 ° C, preferably 50 ° C to 80 ° C. The drying time is usually 60 seconds to 600 seconds, preferably 120 seconds to 600 seconds. In this manner, the polyvinyl alcohol-based resin film was uniaxially stretched, dyed with a dichroic dye, and treated with boric acid to obtain a polarizer. The thickness of the polarizer is usually in a range of 5 μm to 40 μm, and preferably in a range of 10 μm to 35 μm. Protective film As the protective film, various transparent resin films such as a cellulose resin film, a cycloolefin resin film, an acrylic resin film, and a polyester resin film can be used. When a cellulose-based resin film is used as the protective film, a cellulose acetate-based resin in which at least a part of cellulose is esterified is preferred. For example, triethylammonium cellulose, diethylammonium cellulose, cellulose acetate propionate, and the like are mentioned. The cyclic olefin-based resin is, for example, a thermoplastic resin having a monomer unit of a cyclic olefin such as norbornene and polycyclic norbornene-based monomer. The cyclic olefin-based resin may be a ring-opening polymer of the above-mentioned cyclic olefin. The hydride of the cyclic olefin ring-opening copolymer may also be an addition copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group. In addition, a polar group may be introduced into a cycloolefin-based resin. The method of bonding the polarizer and the protective film using the adhesive composition is not particularly limited, and examples thereof include the following methods: a casting method, a wire rod coating method, a gravure coating method, and a die coating method. Method, dip coating method, spray method, etc. apply the adhesive composition to the polarizer and / or the adhesive surface of the protective film so that the two overlap. The casting method is a method of applying an adhesive composition to the surface of a polarizer or a protective film as a coating object while moving it in a substantially vertical direction, a substantially horizontal direction, or an inclined direction therebetween. . After the above-mentioned adhesive composition is applied, the polarizer and the protective film are held by a nip roll and bonded to each other. In addition, in order to improve the adhesion, the surface of the polarizer and / or the protective film may be appropriately subjected to surface treatments such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, and saponification treatment. As said saponification process, the method of immersing in the alkali aqueous solution, such as sodium hydroxide and potassium hydroxide, is mentioned. After the polarizer and the protective film are laminated, a drying process is performed. The drying treatment is performed, for example, by spraying hot air, and the temperature at this time is appropriately selected from the range of 50 ° C to 100 ° C. The drying time is usually 30 seconds to 1000 seconds. <Manufacturing method of polarizing plate> Another embodiment of the present invention is a method of manufacturing the above-mentioned polarizing plate, which is characterized by comprising: (a) coating both sides of a polarizer with acetamidine modified polyvinyl alcohol A resin composition, a glyoxal cross-linking agent, and an adhesive composition of two or more kinds of water-soluble salts of polyvalent metal ions, at the stage of forming an adhesive layer; (b) using a pressing material on the adhesive layer A stage in which at least one protective film is bonded by a roller to produce a polarizing plate; (c) a stage in which the above-mentioned polarizing plate passes through at least two drying paths for drying. With this method, the moisture content of the polarizing plate can be 2.8% to 4.8%, and the thickness of the adhesive layer contained in the polarizing plate can be adjusted to 30 nm to 200 nm. Therefore, it is possible to manufacture a polarizing plate having the effect of preventing the protective film from being separated from the short side of the polarizer even in a humid heat condition without being accompanied by a reduction in light characteristics, and thus can improve water resistance. Regarding the method for manufacturing a polarizing plate of the present invention, as long as there is no other description, the above-mentioned components of the polarizing plate can be used as the components of the polarizing plate. In the step (b) above, the nip roller is a mechanism for adhering a protective film on at least one side of the polarizer, and at least one nip roller may exist in the direction above and below the polarizer and the protective film, respectively. The pressure rollers located above and below the polarizer and the protective film can apply pressure to the polarizer and the protective film passing therebetween, so that the protective film can be adhered to the polarizer. The pressure of the pressure roller that is applied for the adhesion between the polarizer and the protective film may be 0.3 MPa to 0.9 MPa. When the pressure of the pressing roller is less than the above range, the distance between the polarizer and the protective film If the adhesive layer exceeds 200 nm, which is the structure of the present invention, wet heat degradation occurs, and the light characteristics are lowered. When the pressure of the blank exceeds the above range, the adhesive layer may be less than 30 nm, which is the structure of the present invention. bad apperance. The gap between a part of the surface of the nip roller that is in contact with the polarizer and the protective film passing through the nip roller and a part of the surface of the nip roller that is in contact with the above polarizer and the protective film is the nip gap. ) Can be -1500 μm to -500 μm. In the case where the blank gap is less than the above range, the thickness of the adhesive layer is less than 30 nm, which is the structure of the present invention, and appearance defects may occur. In the case that the thickness exceeds the above range, the thickness of the adhesive layer exceeds The 200 nm structure of the present invention suffers from the problem of deterioration in moist heat and degradation of optical characteristics. At this time, the nip rollers located above and below the polarizer and the protective film for measuring the nip interval are set to the nip rollers closest to each other. In the step (b), the polarizing plate obtained by bonding the protective film adhered to at least one side of the polarizer by using a pressure roller can be dried in at least two drying passages in the step (c). In the present invention, for the sake of convenience, the plurality of drying passages are named as the first drying passage, the second drying passage, the third drying passage, etc. in the order in which the polarizing plate passes. The above drying path can use hot air. When the polarizing plate passes through at least two drying paths, the temperature of the hot air in the drying path in the subsequent stage is preferably higher than the temperature of the hot air in the drying path in the previous stage. For example, the temperature of the hot air in the second drying passage is higher than the temperature of the hot air in the first drying passage. More specifically, the temperature of the hot air in the first drying passage is preferably 50 ° C. or lower, and the temperature of the hot air in the last drying passage in the plurality of drying passages is preferably 80 ° C. or higher. When the temperature in the first drying path exceeds 50 ° C, damp heat degradation occurs due to rapid moisture evaporation, and the light characteristics are reduced. When the temperature of the hot air in the final drying path is less than 80 ° C, the moisture content of the polarizing plate Increasing the rate may cause a problem that the optical characteristics decrease with time. <Image Display Device> Another aspect of the present invention is an image display device including the above-mentioned polarizing plate. The image display device of the present invention includes the above-mentioned polarizing plate. Specific examples include a liquid crystal display, an OLED, and a flexible display, but the invention is not limited thereto. In order to help the understanding of the present invention, a preferred embodiment is provided below. The following embodiments are merely examples of the present invention. Various changes and modifications can be made within the scope of the present invention and the technical idea. It is clear to the skilled person that such deformations and amendments belong to the scope of the attached patent application, and this is of course. In the following examples and comparative examples, "%" and "parts" indicating content are based on weight unless otherwise specified. Manufacturing Example Manufacturing Example 1. Manufacturing of Polarizer A 75 μm-thick polyvinyl alcohol film having an average degree of polymerization of 2400 and a degree of saponification of 99.9 mol% or more was subjected to dry uniaxial stretching by about 5 times, while maintaining the stretched state. After being immersed in water (distilled water) at 60 ° C for 1 minute, it was immersed in a 28 ° C aqueous solution having a weight ratio of iodine / potassium iodide / distilled water at 0.05 / 5/100 for 60 seconds. Then, it was immersed in a 72 ° C aqueous solution with a weight ratio of potassium iodide / boric acid / distilled water of 8.5 / 8.5 / 100 for 300 seconds, washed with distilled water at 26 ° C for 20 seconds, and then dried at 65 ° C to produce a film of iodine in PVA. Polarizer with adsorption orientation. Production Example 2. Production of Protective Film KC8UX (Konica, T), which is a triethyl cellulose based film, was saponified and used. Manufacture example 3. Manufacture of adhesive composition Manufacture of liquid A composition: dissolving acetamethylene modified polyvinyl alcohol-based resin (セ ノ ー セ ノ ー ル Z200, Japan) with a degree of saponification of 99.2 mol% in water (distilled water) Synthetic Chemical Industry Co., Ltd.) to produce an aqueous solution whose solid content is shown in Table 1. A 40% aqueous solution of glyoxal cross-linking agent (Oai Kagaku) was added to the above-mentioned aqueous solution at the content described in Table 1, and then mixed to produce an adhesive agent A liquid composition. Production of liquid B composition: dissolved in water (distilled water) with 99.2 mol% of acetoacetic acid modified polyvinyl alcohol resin (树脂 ー セ ノ ル 200200, Nippon Synthetic Chemical Industry Co., Ltd.), and produced a solid component The content is shown in Table 1 as an aqueous solution. To the above-mentioned aqueous solution, zinc chloride (Oi Kagaku) and zinc nitrate (Oi Kagaku), which are water-soluble salts of polyvalent metal ions, were added at the contents described in Table 1 to prepare an adhesive B liquid composition. . The A liquid composition and the B liquid composition prepared above were mixed at normal temperature and stirred for about 30 minutes to produce an adhesive composition. Example 1 to Example 8 and Comparative Example 1 to Comparative Example 7 : Manufacture of polarizing plate Both sides of the polarizer manufactured in Manufacturing Example 1 above were coated with the content described in Table 1 and manufactured by the method of Manufacturing Example 3 above After the adhesive composition, the protective film of Production Example 2 was bonded by a nip roll. At this time, the process conditions (pressing pressure, pressing gap) are as shown in Table 1, and the polarizing plates bonded by the pressing roller are dried by a hot air dryer in the drying passage. The drying process is performed in a total of 5 stages. The temperature of the hot air in the first drying passage and the temperature of the hot air in the fifth drying passage are as shown in Table 1. In addition, the temperature of the hot air in the second drying passage is 50 ° C. The temperature of the hot air in the third drying passage was 70 ° C, and the temperature of the hot air in the fourth drying passage was 75 ° C. Drying was performed in each drying passage for 5 minutes, and a polarizing plate was finally manufactured. The moisture content of the thus-produced polarizing plate and the thickness of the adhesive layer contained in the polarizing plate were measured and described in Table 1. At this time, the moisture content of the above-mentioned polarizing plate was measured by a weight moisture content measurement method observing a change in weight before / after a heat treatment at 105 ° C for 2 hours. [Table 1] 1. After the experimental examples Relay sticky Evaluation (Evaluation cutting tool) of the above-described manufacturing a polarizing plate placed at room temperature for 1 hour, in the film between the polarizing plates (polarizer and the polarizer protective film between) cutting into The cutting edge of the cutter was evaluated in accordance with the following criteria for the manner in which the cutting edge was advanced when the blade was advanced, and the results are shown in Table 2. ：: The blade of the cutting tool did not enter all the membranes. ○: When the blade is advanced, the blade stops when it enters 1 mm to 2 mm between at least one of the membranes. △: When the blade is advanced, the blade stops when it enters 3 mm to 5 mm between at least one of the membranes. ×: When the blade is advanced, the blade can easily enter between at least one of the membranes. Experimental example 2. Evaluation of water resistance About each polarizing plate which was left for 24 hours in an environment of 23 ° C. and a relative humidity of 55%, a temperature-resistant water resistance test was performed by the method described below to evaluate water resistance. The long axis of the polarizing plate was used as the long side, and the polarizing plate was cut to a size of 5 cm × 2 cm to prepare a sample, and the dimension in the long side direction was accurately measured. At this time, due to the iodine adsorbed on the polarizing film, the above-mentioned sample uniformly and uniformly exhibited a unique color. FIG. 1 is a diagram schematically showing a method for evaluating water resistance, (A) shows sample 1 before warm water immersion, and (B) shows sample 1 after warm water immersion. As shown in FIG. 1 (A), generally, one of the short sides of the sample was held with a holding tool 5 and about 80% of the length was immersed in a water bath at 60 ° C. for 8 hours. Then, the sample 1 was taken out of the water tank, and the water was wiped off. By the above-mentioned warm water immersion, the polarizer 4 of the polarizing plate contracts. The degree of shrinkage of the above-mentioned polarizer 4 was evaluated by measuring the distance from the end portion 1a (the end of the protective film) at the center of the short side of the sample 1 to the end of the contracted polarizer 4, and it was set as the contracted length. In addition, as shown in FIG. 1 (B), the polarizer 4 located at the center of the polarizing plate was shrunk by immersion in warm water, so that iodine was dissolved from the peripheral portion of the polarizer 4 between the protective films 2 and the sample Decolored part 3 is generated in the peripheral part of 1. The degree of such discoloration was evaluated by measuring the distance from the end of the polarizer 4 contracted at the center of the short side of the sample 1 to the region where the color peculiar to the polarizing plate remained, and the length was decolorized by iodine. The sum of the contraction length and the length of iodine discoloration is taken as the total etching length x. The total etching length x is the distance from the end portion 1a of the sample 1 at the center of the short side of the sample 1 to the region where the color of the polarizing plate is unique. The smaller the shrinkage length, the discoloration length of iodine, and the total erosion length x, the higher the adhesion can be determined in the presence of water. Based on the total etch length x, it was evaluated by the following four grades, and the results are shown in Table 2. ◎: Total etch length x less than 0.1 mm ○: Total etch length x is 0.1 mm or more and less than 0.5 mm △: Total etch length x is 0.5 mm or more and less than 2 mm ×: Total etch length x is 2 mm or more Experimental Example 3. Transmittance and polarization (%) The manufactured polarizing plate was cut to a size of 4 cm × 4 cm, a test piece was produced, and the test piece was attached to a measurement stand, and then a UV-visible spectrometer (V -7100, manufactured by JASCO Corporation). The results are shown in Table 2. [Table 2] With reference to Table 2, it was confirmed that the content of the solid content in the aqueous solution of the ethyl acetate-modified polyvinyl alcohol-based resin was less than the preferred range (2.5% to 4.5% by weight) of the present invention (comparative example) 1) Compared with the case that satisfies the preferred range of the present invention (Examples 1 to 8), the moisture content of the polarizing plate is insufficient and the water resistance is poor. In the case of exceeding the above range (Comparative Example 2), the moisture content of the polarizing plate As the rate increases, the thickness of the adhesive layer contained in the polarizing plate becomes thicker, which causes a problem that the light characteristics decrease. In addition, it was confirmed that when the process conditions (pressing pressure, press gap) of the polarizing plate of the present invention deviate from the scope of the present invention (Comparative Examples 3 to 4), the moisture content of the polarizing plate deviating from the requirements of the present invention, It was confirmed that the polarizing plate of the thickness range of the adhesive layer contained in the polarizing plate was reduced in water resistance and light characteristics. When the temperature of the hot air in the first drying path during the drying of the polarizing plate exceeds the temperature range of the present invention (50 ° C or lower) (Example 7), the moisture content and the moisture content of the polarizing plate required in the present invention can be satisfied. The thickness range of the adhesive layer contained in the polarizing plate, but compared with the case (Examples 1 to 6 and 8) that satisfies the above-mentioned temperature range, there is a problem that the light characteristics are slightly reduced. For the fifth drying path, When the temperature range of the hot air is out of the temperature range of the present invention (80 ° C or higher) (Comparative Example 5), it has been confirmed that the moisture content of the polarizing plate exceeding the requirements of the present invention, and the water resistance and light characteristics appear. reduce. In addition, when only one water-soluble salt of a polyvalent metal ion was used (Comparative Examples 6 and 7), it was confirmed that the water resistance was decreased.

1‧‧‧樣品
1a‧‧‧末端部
2‧‧‧保護膜
3‧‧‧脫色之部分
4‧‧‧偏光器
5‧‧‧把持具1‧‧‧ sample
1a‧‧‧ tip
2‧‧‧ protective film
3‧‧‧ discoloration
4‧‧‧ polarizer
5‧‧‧Grip

圖1是示意地表示根據實驗例之耐水性之評價試驗方法的圖。FIG. 1 is a view schematically showing a test method for evaluating water resistance according to an experimental example.

1‧‧‧樣品 1‧‧‧ sample

1a‧‧‧末端部 1a‧‧‧ tip

2‧‧‧保護膜 2‧‧‧ protective film

3‧‧‧脫色之部分 3‧‧‧ discoloration

4‧‧‧偏光器 4‧‧‧ polarizer

5‧‧‧把持具 5‧‧‧Grip

Claims (15)

一種偏光板，其包含：在一偏光器之至少一面經由一黏接劑層接合之一保護膜，其特徵在於，該偏光板之一水分率為2.8%至4.8%，該黏接劑層由包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之一水溶性鹽之一黏接劑組合物形成，該黏接劑層之一厚度為30 nm 至200 nm。A polarizing plate includes: a protective film bonded on at least one side of a polarizer via an adhesive layer, characterized in that a moisture content of one of the polarizing plates is 2.8% to 4.8%, and the adhesive layer consists of An adhesive composition comprising an acetamidine-modified polyvinyl alcohol-based resin, a glyoxal cross-linking agent, and one or more water-soluble salts of two or more polyvalent metal ions is formed. One of the adhesive layers is formed. The thickness is 30 nm to 200 nm. 如請求項1之偏光板，其中，該黏接劑組合物包含：包含乙醯乙醯基改性聚乙烯醇系樹脂水溶液及乙二醛交聯劑之一A液，以及包含乙醯乙醯基改性聚乙烯醇系樹脂水溶液及2種以上之多價金屬離子之一水溶性鹽之一B液。The polarizing plate according to claim 1, wherein the adhesive composition comprises: an A solution containing an ethyl acetate-modified polyvinyl alcohol-based resin aqueous solution and a glyoxal cross-linking agent, and an ethyl acetate containing ethyl acetate A modified aqueous solution of a polyvinyl alcohol-based resin and a liquid B which is one of the water-soluble salts of two or more kinds of polyvalent metal ions. 如請求項2之偏光板，其中，相對於乙醯乙醯基改性聚乙烯醇系樹脂水溶液100重量%，該A液及該B液各自所含有之乙醯乙醯基改性聚乙烯醇系樹脂之一固體成分之一含量為2.5重量%至4.5重量%。For example, the polarizing plate of claim 2, wherein each of the A liquid and the B liquid contains ethyl ethyl acetate modified polyvinyl alcohol with respect to 100% by weight of the ethyl ethyl acetate modified polyvinyl alcohol-based resin aqueous solution. The content of one solid component of the series resin is 2.5% to 4.5% by weight. 如請求項1之偏光板，其中，該多價金屬離子之水溶性鹽為選自氯化鋅、硝酸鋅及硝酸鋁中之2種以上。The polarizing plate according to claim 1, wherein the water-soluble salt of the polyvalent metal ion is two or more kinds selected from zinc chloride, zinc nitrate, and aluminum nitrate. 如請求項1之偏光板，其中，該乙醯乙醯基改性聚乙烯醇系樹脂之一平均聚合度為100至1500。The polarizing plate according to claim 1, wherein an average degree of polymerization of one of the acetamidine-modified polyvinyl alcohol resins is 100 to 1500. 如請求項2之偏光板，其中，相對於該A液中所含之乙醯乙醯基改性聚乙烯醇系樹脂之一固體成分總100重量份，該A液中所含之乙二醛系交聯劑之一含量為30重量份至70重量份。For example, the polarizing plate of claim 2, wherein the glyoxal contained in the A liquid is 100 parts by weight with respect to 100 parts by weight of the total solid content of one of the ethyl acetate-modified polyvinyl alcohol-based resin contained in the A liquid. The content of one of the crosslinking agents is 30 parts by weight to 70 parts by weight. 如請求項2之偏光板，其中，該多價金屬離子之水溶性鹽包含選自氯化鋅、硝酸鋅及硝酸鋁中之2種以上，相對於該B液中所含之乙醯乙醯基改性聚乙烯醇系樹脂之一固體成分總100重量份，該氯化鋅之一含量為2重量份至10重量份。The polarizing plate of claim 2, wherein the water-soluble salt of the polyvalent metal ion contains two or more kinds selected from the group consisting of zinc chloride, zinc nitrate, and aluminum nitrate, relative to the ethyl acetate contained in the liquid B. The solid content of one of the base-modified polyvinyl alcohol-based resins is 100 parts by weight in total, and the content of one of the zinc chlorides is 2 to 10 parts by weight. 如請求項2之偏光板，其中，該多價金屬離子之水溶性鹽包含選自氯化鋅、硝酸鋅及硝酸鋁中之2種以上，相對於該B液中所含之乙醯乙醯基改性聚乙烯醇系樹脂之一固體成分總100重量份，該硝酸鋅或硝酸鋁之一含量為30重量份至90重量份。The polarizing plate of claim 2, wherein the water-soluble salt of the polyvalent metal ion contains two or more kinds selected from the group consisting of zinc chloride, zinc nitrate, and aluminum nitrate, relative to the ethyl acetate contained in the liquid B. One solid component of the base-modified polyvinyl alcohol-based resin is 100 parts by weight in total, and the content of one of the zinc nitrate or aluminum nitrate is 30 to 90 parts by weight. 一種影像顯示裝置，其包含如請求項1至8中任一項所述之偏光板。An image display device includes the polarizing plate according to any one of claims 1 to 8. 一種偏光板之製造方法，是一偏光板之一水分率為2.8%至4.8%、該偏光板中所含之一黏接劑層之一厚度為30 nm至200 nm之偏光板的製造方法，其特徵在於，包含： (a)在偏光器之兩面塗佈包含乙醯乙醯基改性聚乙烯醇系樹脂、乙二醛交聯劑及2種以上之多價金屬離子之一水溶性鹽的一黏接劑組合物，生成黏接劑層之一階段； (b)在該黏接劑層上採用一壓料輥將至少一個以上之保護膜接合，製作偏光板之一階段；及 (c)該偏光板通過至少2個以上之乾燥通路而被乾燥之一階段。A manufacturing method of a polarizing plate is a manufacturing method of a polarizing plate having a moisture content of 2.8% to 4.8% of a polarizing plate and a thickness of 30 nm to 200 nm of an adhesive layer contained in the polarizing plate. It is characterized by comprising: (a) coating both sides of the polarizer with a water-soluble salt containing an ethyl acetofluorene-modified polyvinyl alcohol resin, a glyoxal cross-linking agent, and two or more kinds of polyvalent metal ions; A phase of forming an adhesive layer; (b) a stage in which at least one protective film is bonded to the adhesive layer by using a pressure roller to produce a polarizing plate; and ( c) The polarizing plate is dried in at least two stages through at least two drying paths. 如請求項10之偏光板之製造方法，其中，該(b)階段中對偏光板施加之一壓料輥之一壓料壓力為0.3 MPa 至0.9 MPa。For example, the method of manufacturing a polarizing plate according to claim 10, wherein in the step (b), a pressing pressure of a pressing roller applied to the polarizing plate is 0.3 MPa to 0.9 MPa. 如請求項10之偏光板之製造方法，其中，該(b)階段中壓料間隙為‑1500 μm至-500 μm。For example, the manufacturing method of the polarizing plate of claim 10, wherein the blank gap in the step (b) is ‑1500 μm to -500 μm. 如請求項10之偏光板之製造方法，其中，該(c)階段中，偏光板通過至少2個以上之乾燥通路時，後續階段之乾燥通路內之一熱風的一溫度比前一階段之乾燥通路內之一熱風的一溫度高。For example, the manufacturing method of the polarizing plate of claim 10, wherein, in the step (c), when the polarizing plate passes through at least two drying passages, a temperature of a hot air in the drying passage in the subsequent stage is higher than that in the previous stage. One of the hot winds in the passage has a high temperature. 如請求項13之偏光板之製造方法，其中，該至少2個以上之乾燥通路中最初存在之第1乾燥通路內之一熱風的一溫度為50℃以下。For example, the method for manufacturing a polarizing plate according to claim 13, wherein a temperature of a hot air in the first drying path existing in the at least two or more drying paths is 50 ° C or lower. 如請求項13之偏光板之製造方法，其中，該至少2個以上之乾燥通路中最終存在之乾燥通路內之一熱風之一溫度為80℃以上。For example, the method for manufacturing a polarizing plate according to claim 13, wherein a temperature of one of hot air in the drying path finally existing in the at least two or more drying paths is 80 ° C or more.