TWI684032B - Method for manufacturing polarizing film and polarizing film - Google Patents

Abstract

本發明提供一種偏光膜之製造方法、偏光膜及包含偏光膜之偏光板，該製造方法包含：染色步驟，其利用二色性色素將聚乙烯醇系樹脂膜染色；交聯步驟，其利用交聯劑處理染色步驟後之膜；及高溫高濕處理步驟，其將作為交聯步驟後之膜且處於濕潤狀態之膜置於溫度40~100℃、絕對濕度40g/m³以上之環境下；該偏光膜係使二色性色素吸附配向於聚乙烯醇系樹脂膜而成者，且具有特定配向度(%)。 The present invention provides a method for manufacturing a polarizing film, a polarizing film, and a polarizing plate including the polarizing film. The manufacturing method includes: a dyeing step that uses a dichroic dye to dye the polyvinyl alcohol-based resin film; a cross-linking step that uses cross-linking The film after the dyeing step is treated by the linking agent; and the high-temperature and high-humidity treatment step, which places the film which is the film after the cross-linking step and is in a wet state under an environment with a temperature of 40 to 100°C and an absolute humidity of 40 g/m ³ or more; This polarizing film is made by aligning a dichroic dye to a polyvinyl alcohol-based resin film, and has a specific degree of alignment (%).

Description

偏光膜之製造方法及偏光膜 Method for manufacturing polarizing film and polarizing film

本發明係關於一種可用作偏光板之構成構件之偏光膜之製造方法。又，本發明係關於一種偏光膜及包含其之偏光板。 The present invention relates to a method for manufacturing a polarizing film that can be used as a constituent member of a polarizing plate. In addition, the present invention relates to a polarizing film and a polarizing plate including the same.

關於偏光膜，先前使用使碘或二色性染料般之二色性色素吸附配向於經單軸延伸之聚乙烯醇系樹脂膜而成者。通常而言，偏光膜係藉由依序實施利用二色性色素將聚乙烯醇系樹脂膜染色之染色處理、利用交聯劑進行處理之交聯處理，且於製造步驟之間實施單軸延伸處理而製造[例如日本專利特開平7-325218號公報(專利文獻1)]。 Regarding the polarizing film, a polyvinyl alcohol-based resin film that uniaxially stretches a dichroic dye such as iodine or a dichroic dye is adsorbed and aligned. In general, the polarizing film is sequentially dyed with a dichroic dye to dye a polyvinyl alcohol-based resin film, and cross-linked with a cross-linking agent, and uniaxially stretched between manufacturing steps And manufacture [for example, Japanese Patent Laid-Open No. 7-325218 (Patent Document 1)].

[先前技術文獻] [Prior Technical Literature] [專利文獻] [Patent Literature]

[專利文獻1]日本專利特開平7-325218號公報 [Patent Document 1] Japanese Patent Laid-Open No. 7-325218

偏光膜被用於液晶顯示裝置所代表之圖像顯示裝置。關於偏光膜，通常將保護膜貼合於其單面或雙面，製成偏光板，組裝入圖像顯示裝置。例如液晶顯示裝置搭載將偏光板貼合於作為圖像顯示元件之液晶單元之雙面而成之液晶面板。 The polarizing film is used for an image display device represented by a liquid crystal display device. Regarding the polarizing film, the protective film is usually attached to one or both sides of the polarizing film to form a polarizing plate, which is incorporated into an image display device. For example, a liquid crystal display device is equipped with a liquid crystal panel formed by bonding a polarizing plate to both sides of a liquid crystal cell as an image display element.

近年來，逐漸要求偏光板之薄型化，於偏光板為薄型之情形時，尤其容易於高溫環境下及高濕環境下產生翹曲(彎曲)。若將產生翹曲之偏光板貼合於液晶單元，構建液晶面板，則視情形亦於液晶面 板產生翹曲。有液晶面板之翹曲對液晶顯示裝置之視認性造成壞影響之虞。 In recent years, the thinning of the polarizing plate is gradually required. When the polarizing plate is thin, it is particularly easy to warp (bend) in a high-temperature environment and a high-humidity environment. If the polarizing plate with warpage is attached to the liquid crystal cell to construct a liquid crystal panel, it will also be on the liquid crystal surface depending on the situation The board is warped. The warpage of the liquid crystal panel may adversely affect the visibility of the liquid crystal display device.

為了抑制偏光板之翹曲、甚至液晶面板之翹曲，較有效為降低用於偏光板之偏光膜之吸收軸方向上之收縮力(以下亦稱為「MD收縮力」)。作為降低MD收縮力之方法，可列舉降低偏光膜製造時之延伸倍率，然而於該方法之情形時，偏光膜之光學特性(例如偏光度)變得不充分。 In order to suppress the warping of the polarizing plate and even the warping of the liquid crystal panel, it is more effective to reduce the shrinkage force in the direction of the absorption axis of the polarizing film used for the polarizing plate (hereinafter also referred to as "MD shrinkage force"). As a method of reducing the MD shrinkage force, a reduction in the stretching magnification of the polarizing film at the time of manufacture can be cited. However, in the case of this method, the optical characteristics (eg, degree of polarization) of the polarizing film become insufficient.

本發明之目的在於提供一種用以製造具有良好光學特性但MD收縮力較小之偏光膜之方法。又，本發明之另一目的在於提供一種具有良好光學特性但MD收縮力較小之偏光膜、及包含其之偏光板。 An object of the present invention is to provide a method for manufacturing a polarizing film having good optical properties but a low MD shrinkage force. In addition, another object of the present invention is to provide a polarizing film having good optical properties but a small MD shrinkage force, and a polarizing plate including the same.

本發明提供以下所示之偏光膜之製造方法、偏光膜及偏光板。 The present invention provides a method of manufacturing a polarizing film, a polarizing film and a polarizing plate shown below.

[1]一種偏光膜之製造方法，其包含：染色步驟，其利用二色性色素將聚乙烯醇系樹脂膜染色；交聯步驟，其利用交聯劑處理染色步驟後之膜；及高溫高濕處理步驟，其將作為交聯步驟後之膜且處於濕潤狀態之膜置於溫度40~100℃、絕對濕度40g/m³以上之環境下。 [1] A method of manufacturing a polarizing film, comprising: a dyeing step that dyes a polyvinyl alcohol-based resin film using a dichroic pigment; a crosslinking step that uses a crosslinking agent to treat the film after the dyeing step; and high temperature In the wet processing step, the film which is the film after the cross-linking step and is in a wet state is placed in an environment with a temperature of 40 to 100° C. and an absolute humidity of 40 g/m ³ or more.

[2]如[1]之製造方法，其進而包含使用含有水之清洗液清洗上述交聯步驟後之膜之清洗步驟，且上述高溫高濕處理步驟係對作為上述清洗步驟後之膜且處於濕潤狀態之膜實施。 [2] The manufacturing method according to [1], which further includes a cleaning step of cleaning the film after the cross-linking step with a cleaning solution containing water, and the high-temperature and high-humidity treatment step is used as the film after the cleaning step and is in Wet film implementation.

[3]如[1]或[2]之製造方法，其中上述高溫高濕處理步驟之處理時間為5秒~60分鐘。 [3] The manufacturing method according to [1] or [2], wherein the processing time of the high temperature and high humidity processing step is 5 seconds to 60 minutes.

[4]如[1]至[3]中任一項之製造方法，其藉由上述高溫高濕處理步驟降低膜之水分率。 [4] The production method according to any one of [1] to [3], which reduces the moisture content of the film through the above-mentioned high-temperature and high-humidity treatment step.

[5]如[4]之製造方法，其中上述高溫高濕處理步驟前後之膜之水 分率差未達15重量%。 [5] The manufacturing method according to [4], wherein the water of the film before and after the high temperature and high humidity treatment step The difference in fractions does not reach 15% by weight.

[6]一種偏光膜，其係使二色性色素吸附配向於聚乙烯醇系樹脂膜而成者，且基於由廣角X射線繞射測定所獲得之方位角分佈曲線，依照下述式：配向度(%)=(360-W)/360 [6] A polarizing film obtained by adsorbing and aligning a dichroic dye to a polyvinyl alcohol-based resin film, and based on the azimuth distribution curve obtained by wide-angle X-ray diffraction measurement, according to the following formula: alignment Degree (%)=(360-W)/360

[式中，W為於將上述方位角分佈曲線之峰總體之積分值設為100%時，對所有峰求出積分值成為50%之峰全寬時之該等之和]求出之配向度於上述偏光膜之厚度為20μm以上時為71%以下，於上述偏光膜之厚度為10μm以上且未達20μm時為74.0%以下。 [In the formula, W is the sum of the total width of the peaks when the integral value of the peaks of the above azimuth distribution curve is set to 100%, and the integral value becomes the peak width of 50% for all peaks.] The degree is 71% or less when the thickness of the polarizing film is 20 μm or more, and 74.0% or less when the thickness of the polarizing film is 10 μm or more and less than 20 μm.

[7]一種偏光板，其包含如[6]之偏光膜、及積層於其至少一面上之保護膜。 [7] A polarizing plate comprising the polarizing film as described in [6], and a protective film laminated on at least one side thereof.

根據本發明，能夠提供一種具有良好光學特性但MD收縮力較小之偏光膜及其製造方法。使用本發明之偏光膜之偏光板及液晶面板於高溫環境下或高濕環境下難以產生翹曲。 According to the present invention, it is possible to provide a polarizing film having good optical properties but a small MD shrinkage force and a method of manufacturing the same. The polarizing plate and the liquid crystal panel using the polarizing film of the present invention are difficult to warp in a high-temperature environment or a high-humidity environment.

圖1係表示本發明之偏光膜之製造方法之一例之流程圖。 FIG. 1 is a flowchart showing an example of a method of manufacturing a polarizing film of the present invention.

圖2係表示基底修正後之方位角分佈曲線之一例之圖。 FIG. 2 is a diagram showing an example of the azimuth distribution curve after base correction.

<偏光膜之製造方法> <Manufacturing method of polarizing film>

參照圖1，本發明之偏光膜之製造方法包含以下步驟：染色步驟S20，其利用二色性色素將聚乙烯醇系樹脂膜染色；交聯步驟S30，其利用交聯劑處理染色步驟後之膜；及高溫高濕處理步驟S50，其將作為交聯步驟後之膜且處於濕潤狀態之膜置於溫度40~100℃、絕對濕度40g/m³以上之環境下。 1, the method for manufacturing a polarizing film of the present invention includes the following steps: a dyeing step S20, which uses a dichroic dye to dye the polyvinyl alcohol-based resin film; a crosslinking step S30, which uses a crosslinking agent to process the dyeing step Membrane; and high temperature and high humidity treatment step S50, which places the membrane in the wet state as the membrane after the cross-linking step in an environment with a temperature of 40 to 100°C and an absolute humidity of 40 g/m ³ or more.

本發明之偏光膜之製造方法可進而包含上述以外之其他步驟，其具體例如圖1所示，為於染色步驟S20之前進行之膨潤步驟S10、及於交聯步驟S30之後進行之清洗步驟S40。又，聚乙烯醇系樹脂膜於偏光膜製造步驟之任意1個以上階段，更具體而言，於自膨潤步驟S10之前至交聯步驟S30之任意1個以上階段進行單軸延伸處理(延伸步驟)。 The method for manufacturing a polarizing film of the present invention may further include other steps than the above. For example, as shown in FIG. 1, it is a swelling step S10 performed before the dyeing step S20 and a cleaning step S40 performed after the crosslinking step S30. In addition, the polyvinyl alcohol-based resin film is uniaxially stretched at any one or more stages of the polarizing film manufacturing step, more specifically, at any one or more stages from the swelling step S10 to the crosslinking step S30 (stretching step) .

本發明之製造方法所含之各種處理步驟可藉由沿著偏光膜製造裝置之膜搬送路徑連續地搬送作為坯膜之聚乙烯醇系樹脂膜而連續地實施。膜搬送路徑以該等實施順序具備用以實施上述各種處理步驟之設備(處理浴或爐等)。所謂處理浴，意指如膨潤浴、染色浴、交聯浴、清洗浴般之收容對聚乙烯醇系樹脂膜實施處理之處理液之浴。 The various processing steps included in the manufacturing method of the present invention can be continuously performed by continuously transporting the polyvinyl alcohol-based resin film as a raw film along the film transport path of the polarizing film manufacturing apparatus. The film conveying path is equipped with equipment (processing bath, furnace, etc.) for implementing the above-mentioned various processing steps in these execution orders. The so-called treatment bath means a bath containing a treatment liquid for treating the polyvinyl alcohol-based resin film like a swelling bath, a dyeing bath, a cross-linking bath, and a cleaning bath.

膜搬送路徑可藉由除上述設備以外亦將導輥或夾輥等配置於適當位置而構建。例如，導輥可配置於各處理浴之前後或處理浴中，藉此能夠進行膜向處理浴之導入、浸漬及自處理浴之抽出。更具體而言，藉由於各處理浴中設置2根以上導輥，沿著該等導輥搬送膜，能夠使膜浸漬於各處理浴。 The film conveying path can be constructed by arranging guide rollers, nip rollers, and the like at appropriate positions in addition to the above-mentioned equipment. For example, the guide roller can be arranged before or after each treatment bath or in the treatment bath, whereby the introduction of the film into the treatment bath, dipping, and extraction from the treatment bath can be performed. More specifically, by providing two or more guide rollers in each processing bath and transporting the film along the guide rollers, the film can be immersed in each processing bath.

作為構成坯膜即聚乙烯醇系樹脂膜之聚乙烯醇系樹脂，可使用將聚乙酸乙烯酯系樹脂皂化而成者。作為聚乙酸乙烯酯系樹脂，除作為乙酸乙烯酯之均聚物之聚乙酸乙烯酯以外，例示乙酸乙烯酯與可與其共聚之其他單體之共聚物。作為可與乙酸乙烯酯共聚之其他單體，例如可列舉：不飽和羧酸類、烯徑類、乙烯醚類、不飽和磺酸類、具有銨基之(甲基)丙烯醯胺類等。聚乙烯醇系樹脂之皂化度通常為約85莫耳%以上，較佳為約90莫耳%以上，更佳為約99莫耳%以上。本說明書中，所謂「(甲基)丙烯酸」，意指選自丙烯酸及甲基丙烯酸之至少一者。關於「(甲基)丙烯醯基」，亦為相同。 As the polyvinyl alcohol-based resin that constitutes the polyvinyl alcohol-based resin film that is a green film, a saponified polyvinyl acetate-based resin can be used. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable therewith is exemplified. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, vinylene compounds, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group. The saponification degree of the polyvinyl alcohol-based resin is usually about 85 mol% or more, preferably about 90 mol% or more, and more preferably about 99 mol% or more. In this specification, "(meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. The same applies to "(meth)acryloyl".

聚乙烯醇系樹脂亦可經改性，例如亦可使用經醛類改性之聚乙烯醇縮甲醛、聚乙烯醇縮乙醛、聚乙烯醇縮丁醛等。 The polyvinyl alcohol-based resin may be modified. For example, polyvinyl acetal modified with aldehydes, polyvinyl acetal, polyvinyl butyral, etc. may be used.

聚乙烯醇系樹脂之平均聚合度較佳為100~10000，更佳為1500~8000，進而較佳為2000~5000。聚乙烯醇系樹脂之平均聚合度可依據JIS K 6726(1994)求出。若平均聚合度未達100，則難以獲得較佳偏光性能，若超過10000，則有時膜加工性較差。 The average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10,000, more preferably 1500 to 8000, and further preferably 2000 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726 (1994). If the average degree of polymerization is less than 100, it is difficult to obtain better polarizing performance, and if it exceeds 10,000, the film processability may be poor.

聚乙烯醇系樹脂膜之厚度例如為10~150μm左右，就偏光膜之薄型化之觀點而言，較佳為100μm以下，更佳為70μm以下，進而較佳為50μm以下，進一步較佳為40μm以下。 The thickness of the polyvinyl alcohol-based resin film is, for example, about 10 to 150 μm. From the viewpoint of thinning the polarizing film, it is preferably 100 μm or less, more preferably 70 μm or less, still more preferably 50 μm or less, and still more preferably 40 μm. the following.

作為坯膜之聚乙烯醇系樹脂膜例如可以長條之未延伸聚乙烯醇系樹脂膜之輥狀物(捲繞品)之形式準備。於該情形時，偏光膜亦以長條物之形式獲得。以下，就各步驟詳細地說明。 The polyvinyl alcohol-based resin film as the raw film can be prepared, for example, in the form of a long roll of unstretched polyvinyl alcohol-based resin film (wound product). In this case, the polarizing film is also obtained in the form of a long object. Hereinafter, each step will be described in detail.

(1)膨潤步驟S10 (1) Swell step S10

本步驟之膨潤處理係以作為坯膜之聚乙烯醇系樹脂膜之異物去除、塑化劑去除、易染色性之賦予、膜之塑化等為目的而視需要實施之處理，具體而言，可為將聚乙烯醇系樹脂膜浸漬於含有水之膨潤浴中之處理。該膜可浸漬於一膨潤浴中，亦可依序浸漬於兩個以上膨潤浴中。亦可於膨潤處理前、膨潤處理時、或膨潤處理前及膨潤處理時，對膜進行單軸延伸處理。 The swelling treatment in this step is a treatment to be carried out as necessary for the purpose of removing foreign matter from the polyvinyl alcohol resin film as a green film, removing the plasticizer, imparting easy dyeability, plasticizing the film, etc., specifically, The polyvinyl alcohol resin film may be immersed in a swelling bath containing water. The membrane can be immersed in a swelling bath or can be immersed in two or more swelling baths in sequence. The film may be uniaxially stretched before swelling treatment, during swelling treatment, or before swelling treatment and during swelling treatment.

膨潤浴可為水(例如純水)，另外，亦可為添加有醇類般之水溶性有機溶劑之水溶液。 The swelling bath may be water (for example, pure water), or it may be an aqueous solution to which an alcohol-like water-soluble organic solvent is added.

浸漬膜時之膨潤浴之溫度通常為10~70℃左右，較佳為15~50℃左右，膜之浸漬時間通常為10~600秒左右，較佳為20~300秒左右。 The temperature of the swelling bath when immersing the film is usually about 10 to 70°C, preferably about 15 to 50°C, and the immersion time of the film is usually about 10 to 600 seconds, preferably about 20 to 300 seconds.

(2)染色步驟S20 (2) Dyeing step S20

本步驟之染色處理係以使二色性色素吸附配向於聚乙烯醇系樹脂膜為目的而進行之處理，具體而言，可為使聚乙烯醇系樹脂膜浸漬於含有二色性色素之染色浴之處理。該膜可浸漬於一染色浴中，亦可 依序浸漬於兩個以上染色浴。為了提高二色性色素之染色性，供於染色步驟之膜亦可實施至少某程度之單軸延伸處理。亦可於染色處理時進行單軸延伸處理代替染色處理前之單軸延伸處理，或者除染色處理前之單軸延伸處理以外，於染色處理時亦進行單軸延伸處理。 The dyeing treatment in this step is a treatment for the purpose of absorbing and aligning the dichroic dye to the polyvinyl alcohol-based resin film. Specifically, it may be a dyeing process in which the polyvinyl alcohol-based resin film is immersed in the dichroic pigment Bath treatment. The membrane can be immersed in a dyeing bath, or Sequentially immerse in more than two dyeing baths. In order to improve the dyeability of the dichroic pigment, the film provided for the dyeing step may also be subjected to at least a certain degree of uniaxial stretching treatment. Uniaxial stretching treatment may be performed during dyeing instead of uniaxial stretching treatment before dyeing, or in addition to uniaxial stretching treatment before dyeing, uniaxial stretching treatment may also be performed during dyeing.

二色性色素可為碘或二色性有機染料。二色性有機染料之具體例含有紅BR、紅LR、紅R、粉紅LB、深紅BL、棗紅GS、天藍LG、檸檬黃、藍BR、藍2R、藏青RY、綠LG、紫LB、紫B、黑H、黑B、黑GSP、黃3G、黃R、橙LR、橙3R、猩紅GL、猩紅KGL、剛果紅、亮紫BK、超級藍G、超級藍GL、超級橙GL、直接天藍、直接耐曬橙S、耐曬黑。二色性色素可僅單獨使用1種，亦可併用2種以上。 The dichroic pigment may be iodine or a dichroic organic dye. Specific examples of dichroic organic dyes include red BR, red LR, red R, pink LB, deep red BL, maroon GS, sky blue LG, lemon yellow, blue BR, blue 2R, navy blue RY, green LG, purple LB, purple B , Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Bright Violet BK, Super Blue G, Super Blue GL, Super Orange GL, Direct Sky Blue, Direct light fast orange S, light fast black. Only one kind of dichroic pigment may be used alone, or two or more kinds may be used in combination.

於將碘用作二色性色素之情形時，染色浴可使用含有碘及碘化鉀之水溶液。可使用碘化鋅等其他碘化物取代碘化鉀，亦可將碘化鉀與其他碘化物併用。又，亦可使碘化物以外之化合物，例如硼酸、氯化鋅、氯化鈷等共存。於添加硼酸之情形時，就含有碘之方面與下述交聯處理區分。關於上述水溶液中之碘之含量，通常水每100重量份中為0.01~1重量份左右。又，關於碘化鉀等碘化物之含量，通常水每100重量份中為0.5~20重量份左右。 When iodine is used as a dichroic pigment, an aqueous solution containing iodine and potassium iodide can be used for the dyeing bath. Other iodides such as zinc iodide can be used instead of potassium iodide, or potassium iodide can be used in combination with other iodides. In addition, compounds other than iodide, such as boric acid, zinc chloride, cobalt chloride, etc., may coexist. When boric acid is added, it is distinguished from the following cross-linking treatment in terms of containing iodine. Regarding the content of iodine in the above-mentioned aqueous solution, it is usually about 0.01 to 1 part by weight per 100 parts by weight of water. The content of iodide such as potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water.

浸漬膜時之染色浴之溫度通常為10~45℃左右，較佳為10~40℃左右，更佳為20~35℃左右，膜之浸漬時間通常為30~600秒左右，較佳為60~300秒左右。 The temperature of the dyeing bath when dipping the film is usually about 10 to 45°C, preferably about 10 to 40°C, more preferably about 20 to 35°C, and the dipping time of the film is usually about 30 to 600 seconds, preferably 60 ~300 seconds or so.

於將二色性有機染料用作二色性色素之情形時，染色浴可使用含有二色性有機染料之水溶液。關於該水溶液中之二色性有機染料之含量，通常水每100重量份中為1×10^-4~10重量份左右，較佳為1×10^-3~1重量份左右。該染色浴中亦可使染色助劑等共存，例如亦可含有硫酸鈉等無機鹽或界面活性劑等。二色性有機染料可僅單獨使用1種，亦可併用2種以上。浸漬膜時之染色浴之溫度例如為20~80℃左 右，較佳為30~70℃左右，膜之浸漬時間通常為30~600秒左右，較佳為60~300秒左右。 When a dichroic organic dye is used as a dichroic dye, an aqueous solution containing a dichroic organic dye can be used for the dyeing bath. Regarding the content of the dichroic organic dye in the aqueous solution, it is usually about 1×10 ⁻⁴ to 10 parts by weight per 100 parts by weight of water, preferably about 1×10 ⁻³ to 1 part by weight. Dyeing aids and the like may coexist in the dyeing bath, and for example, inorganic salts such as sodium sulfate or surfactants may be contained. Only one type of dichroic organic dye may be used alone, or two or more types may be used in combination. The temperature of the dyeing bath when immersing the film is, for example, about 20 to 80°C, preferably about 30 to 70°C, and the immersion time of the film is usually about 30 to 600 seconds, preferably about 60 to 300 seconds.

(3)交聯步驟S30 (3) Crosslinking step S30

利用交聯劑處理染色步驟後之聚乙烯醇系樹脂膜之交聯處理係以基於交聯之耐水化或色相調整等為目的而進行之處理，具體而言，可為使染色步驟後之膜浸漬於含有交聯劑之交聯浴之處理。該膜可浸漬於一交聯浴中，亦可依序浸漬於兩個以上交聯浴。亦可於交聯處理時進行單軸延伸處理。 The cross-linking treatment of the polyvinyl alcohol-based resin film after the dyeing step with a cross-linking agent is performed for the purpose of water resistance or hue adjustment based on the cross-linking, specifically, the film after the dyeing step Immersed in a cross-linking bath containing a cross-linking agent. The membrane can be immersed in a cross-linking bath or can be immersed in more than two cross-linking baths in sequence. Uniaxial extension treatment can also be performed during the cross-linking treatment.

作為交聯劑，可列舉硼酸、乙二醛、戊二醛等，較佳地使用硼酸。亦可併用2種以上交聯劑。關於交聯浴中之硼酸之含量，通常水每100重量份為0.1~15重量份左右，較佳為1~10重量份左右。於二色性色素為碘之情形時，較佳為交聯浴除硼酸以外亦含有碘化物。關於交聯浴中之碘化物之含量，通常水每100重量份為0.1~15重量份左右，較佳為5~12重量份左右。作為碘化物，可列舉碘化鉀、碘化鋅等。又，亦可使碘化物以外之化合物，例如氯化鋅、氯化鈷、氯化鋯、硫代硫酸鈉、亞硫酸鉀、硫酸鈉等共存於交聯浴。 Examples of the crosslinking agent include boric acid, glyoxal, glutaraldehyde, etc., and boric acid is preferably used. Two or more crosslinking agents can also be used together. Regarding the content of boric acid in the cross-linking bath, the water is usually about 0.1 to 15 parts by weight per 100 parts by weight, preferably about 1 to 10 parts by weight. When the dichroic pigment is iodine, it is preferred that the cross-linking bath contains iodide in addition to boric acid. Regarding the content of iodide in the cross-linking bath, water is usually about 0.1 to 15 parts by weight per 100 parts by weight, preferably about 5 to 12 parts by weight. Examples of the iodide include potassium iodide and zinc iodide. In addition, compounds other than iodide, such as zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate, etc., may be coexisted in the crosslinking bath.

浸漬膜時之交聯浴之溫度通常為50~85℃左右，較佳為50~70℃左右，膜之浸漬時間通常為10~600秒左右，較佳為20~300秒左右。 The temperature of the crosslinking bath when immersing the film is usually about 50 to 85°C, preferably about 50 to 70°C, and the immersion time of the film is usually about 10 to 600 seconds, preferably about 20 to 300 seconds.

如上述般，於偏光膜之製造時，聚乙烯醇系樹脂膜於自膨潤步驟S10之前至交聯步驟S30之任意一或兩個以上階段進行單軸延伸處理(延伸步驟、圖1)。就提高二色性色素之染色性之觀點而言，供與染色步驟之膜較佳為實施過至少某程度之單軸延伸處理之膜，或較佳為代替染色處理前之單軸延伸處理，或是除染色處理前之單軸延伸處理以外，於染色處理時進行單軸延伸處理。 As described above, in the production of the polarizing film, the polyvinyl alcohol-based resin film is subjected to uniaxial stretching treatment at any one or two stages from the swelling step S10 to the crosslinking step S30 (stretching step, FIG. 1 ). From the viewpoint of improving the dyeability of the dichroic pigment, the film supplied to the dyeing step is preferably a film that has been subjected to at least a certain degree of uniaxial stretching treatment, or preferably replaces the uniaxial stretching treatment before dyeing treatment, Or in addition to the uniaxial stretching process before the dyeing process, the uniaxial stretching process is performed during the dyeing process.

單軸延伸處理可為於空中進行延伸之乾式延伸、於浴中進行延 伸之濕式延伸之任一者，亦可進行該等兩者。單軸延伸處理可為於2個夾輥間賦予周速差進行縱單軸延伸之輥間延伸、熱輥延伸、拉幅延伸等，較佳為包含輥間延伸。將坯膜作為基準之延伸倍率(於以兩個以上階段進行延伸處理之情形時，該等之累積延伸倍率)為3~8倍左右。為了賦予良好之偏光特性，延伸倍率較佳為設為4倍以上，更佳為設為5倍以上。 Uniaxial stretching process can be dry stretching in the air, stretching in the bath Either one of the wet extensions can be carried out. The uniaxial stretching process may be an inter-roll stretching, a hot-roll stretching, a tenter stretching, etc., which provides a difference in circumferential speed between two nip rolls to perform longitudinal uniaxial stretching, and preferably includes an inter-roll stretching. The stretch ratio based on the green film (when stretch processing is performed in two or more stages, the cumulative stretch ratio of these) is about 3 to 8 times. In order to impart good polarization characteristics, the extension magnification is preferably set to 4 times or more, and more preferably 5 times or more.

(4)清洗步驟S40 (4) Cleaning step S40

本步驟之清洗處理係以去除附著於聚乙烯醇系樹脂膜之多餘之交聯劑或二色性色素等藥劑為目的而視需要實施之處理，且為使用含有水之清洗液清洗交聯步驟後之聚乙烯醇系樹脂膜之處理。具體而言，可為使交聯步驟後之聚乙烯醇系樹脂膜浸漬於清洗浴(清洗液)之處理。該膜可浸漬於一清洗浴中，亦可依序浸漬於兩個以上清洗浴。或者，清洗處理可為將清洗液以淋浴(shower)之形式對交聯步驟後之聚乙烯醇系樹脂膜進行噴霧之處理，亦可為上述浸漬與噴霧之組合。 The cleaning treatment in this step is a treatment that is performed as necessary for the purpose of removing excess cross-linking agents or dichroic pigments attached to the polyvinyl alcohol-based resin film, and is a cleaning cross-linking step using a cleaning solution containing water After the treatment of polyvinyl alcohol resin film. Specifically, it may be a process of immersing the polyvinyl alcohol-based resin film after the crosslinking step in a cleaning bath (cleaning solution). The membrane can be immersed in one cleaning bath or can be immersed in more than two cleaning baths in sequence. Alternatively, the cleaning treatment may be a treatment in which the cleaning solution is sprayed on the polyvinyl alcohol-based resin film after the cross-linking step in the form of a shower, or a combination of the above-mentioned dipping and spraying.

清洗液可為水(例如純水)，另外，亦可為添加有醇類般之水溶性有機溶劑之水溶液。清洗液之溫度例如可為5~40℃左右。 The cleaning liquid may be water (for example, pure water), or it may be an aqueous solution added with a water-soluble organic solvent like alcohol. The temperature of the cleaning liquid may be, for example, about 5-40°C.

清洗步驟S40為任意之步驟，可省略，亦可如下述般，於高溫高濕處理步驟S50中進行清洗處理(高溫高濕處理亦可兼作清洗處理)。較佳為對進行清洗步驟S40後之膜進行高溫高濕處理步驟S50。 The cleaning step S40 is an arbitrary step and can be omitted, or the cleaning process can be performed in the high-temperature and high-humidity processing step S50 as follows (the high-temperature and high-humidity process can also be used as the cleaning process). Preferably, the film after the cleaning step S40 is subjected to a high temperature and high humidity treatment step S50.

(5)高溫高濕處理步驟S50 (5) High temperature and high humidity processing step S50

本步驟之高溫高濕處理係將交聯步驟S30後或清洗步驟S40後之膜置於溫度40~100℃、絕對濕度40g/m³以上之環境下之處理。藉由實施高溫高濕處理，能夠抑制偏光膜之光學特性之劣化，且與進行絕對濕度未達40g/m³之高溫處理(乾燥處理)代替高溫高濕處理之情形相比，能夠縮小其MD收縮力。可認為其原因在於，不打亂二色性色素之配向性，而降低構成偏光膜之聚乙烯醇系樹脂之分子鏈之配向性。 The high-temperature and high-humidity treatment in this step is the treatment of placing the film after the cross-linking step S30 or after the cleaning step S40 in an environment with a temperature of 40 to 100°C and an absolute humidity of 40 g/m ³ or more. By implementing high-temperature and high-humidity treatment, the deterioration of the optical properties of the polarizing film can be suppressed, and the MD can be reduced compared to the case where high-temperature treatment (drying treatment) with an absolute humidity of less than 40 g/m ³ is performed instead of high-temperature and high-humidity treatment. Contractility. It is considered that the reason is that the alignment of the molecular chain of the polyvinyl alcohol-based resin constituting the polarizing film is not disturbed without disturbing the alignment of the dichroic dye.

與此相對，如上述專利文獻1中具體記載之方法般，於在清洗步驟後如先前般實施先前通常進行之絕對濕度未達40g/m³之高溫處理(乾燥處理)，其後實施高溫高濕處理之情形時，令人意外的是MD收縮力不僅不降低，甚至上升。 On the other hand, as in the method specifically described in the above-mentioned Patent Document 1, after the washing step, a high-temperature treatment (drying treatment) with an absolute humidity of less than 40 g/m ^{3 that} is usually performed before is performed as before, and then a high temperature and high In the case of wet treatment, it is surprising that the MD contraction force not only does not decrease, but even increases.

高溫高濕處理係對處於濕潤狀態之交聯步驟S30後或清洗步驟S40後之膜實施。所謂「處於濕潤狀態」，意指將交聯步驟S30後或清洗步驟S40後之高水分率之膜(不進行先前之絕對濕度未達40g/m³之高溫處理(乾燥處理))直接供於高溫高濕處理，更具體而言，意指膜之水分率為13重量%以上(較佳為15重量%以上)。膜之水分率係依照下述實施例之項所記載之方法測定。 The high temperature and high humidity treatment is performed on the film after the cross-linking step S30 or after the cleaning step S40 in the wet state. The so-called "wet state" means that the high moisture content film after the cross-linking step S30 or after the cleaning step S40 (without the previous high-temperature treatment (drying treatment) whose absolute humidity is less than 40g/m ³ ) is directly supplied to The high temperature and high humidity treatment, more specifically, means that the moisture content of the film is 13% by weight or more (preferably 15% by weight or more). The moisture content of the film is measured according to the method described in the following examples.

高溫高濕處理可為將交聯步驟S30後或清洗步驟S40後之膜導入至可調整溫度及濕度之爐(加熱爐)或棚或者室內之處理。除導入至爐(加熱爐)或棚或者室內之處理以外，亦可併用遠紅外線加熱器或熱輥等加熱機構。高溫高濕處理較佳為於清洗步驟S40之後實施，亦可同時進行高溫高濕處理及清洗處理，例如於特定之高溫高濕環境下將清洗液進行噴霧，又，高溫高濕處理亦可兼作清洗處理，例如有藉由置於高溫高濕環境下而實質上進行膜之清洗之情形。 The high-temperature and high-humidity treatment may be a treatment in which the film after the cross-linking step S30 or the cleaning step S40 is introduced into an oven (heating furnace) or shed or room where the temperature and humidity can be adjusted. In addition to the treatment introduced into the furnace (heating furnace), shed or room, a heating mechanism such as a far-infrared heater or a hot roller may be used in combination. The high-temperature and high-humidity treatment is preferably performed after the cleaning step S40, and the high-temperature and high-humidity treatment and the cleaning treatment can also be performed at the same time, for example, spraying the cleaning solution under a specific high-temperature and high-humidity environment, and the high-temperature and high-humidity treatment can also be used In the cleaning process, for example, the film is substantially cleaned by being placed in a high-temperature and high-humidity environment.

高溫高濕處理之溫度如上所述為40℃以上，就更有效地降低MD收縮力之觀點而言，較佳為55℃以上，更佳為60℃以上。又，高溫高濕處理之溫度如上所述為100℃以下，就更有效地抑制光學特性之劣化之觀點而言，較佳為90℃以下。 The temperature of the high-temperature and high-humidity treatment is 40°C or higher as described above, and from the viewpoint of more effectively reducing the MD shrinkage force, it is preferably 55°C or higher, and more preferably 60°C or higher. In addition, the temperature of the high-temperature and high-humidity treatment is 100° C. or lower as described above. From the viewpoint of more effectively suppressing the deterioration of optical characteristics, it is preferably 90° C. or lower.

高溫高濕處理之絕對濕度如上所述為40g/m³以上，就更有效地降低MD收縮力之觀點而言，較佳為75g/m³以上，更佳為85g/m³以上，進而較佳為100g/m³以上。另一方面，若絕對濕度過高，則擔心處理區域內之冷凝之產生、或冷凝水所導致之膜之污染，故絕對濕度較佳為550g/m³以下，更佳為400g/m³以下，進而較佳為300g/m³以 下，尤佳為160g/m³以下。 The absolute humidity of the high-temperature and high-humidity treatment is 40 g/m ³ or more as described above. From the viewpoint of more effectively reducing the MD shrinkage force, it is preferably 75 g/m ³ or more, more preferably 85 g/m ³ or more, and further It is preferably 100 g/m ³ or more. On the other hand, if the absolute humidity is too high, there is a concern about the occurrence of condensation in the treatment area or membrane contamination caused by condensation water, so the absolute humidity is preferably 550 g/m ³ or less, more preferably 400 g/m ³ or less It is further preferably 300 g/m ³ or less, and particularly preferably 160 g/m ³ or less.

關於高溫高濕處理之時間，就更有效地降低MD收縮力之觀點而言，較佳為5秒以上，更佳為10秒以上。又，該時間亦取決於溫度，若過長，則擔心光學特性之劣化，故較佳為60分鐘以下，更佳為30分鐘以下，進而較佳為10分鐘以下，尤佳為5分鐘以下。 Regarding the time of the high-temperature and high-humidity treatment, from the viewpoint of more effectively reducing the MD shrinkage force, it is preferably 5 seconds or more, and more preferably 10 seconds or more. In addition, the time depends on the temperature. If it is too long, the optical characteristics may be deteriorated. Therefore, it is preferably 60 minutes or less, more preferably 30 minutes or less, further preferably 10 minutes or less, and particularly preferably 5 minutes or less.

高溫高濕處理可為沿著膜搬送路徑搬送長條之聚乙烯醇系樹脂膜，連續地導入至上述爐等使其通過之處理，關於此種高溫高濕處理中之膜之張力，就更有效地降低MD收縮力之觀點而言，較佳為50~5000N/m。就抑制膜之皺褶產生之觀點而言，膜張力更佳為300N/m以上。 The high-temperature and high-humidity treatment may be a process in which a long polyvinyl alcohol-based resin film is transported along the film transport path and continuously introduced into the above-mentioned furnace and the like, and the film tension in such high-temperature and high-humidity processing is even more From the viewpoint of effectively reducing the MD shrinkage force, it is preferably 50 to 5000 N/m. From the viewpoint of suppressing the generation of wrinkles of the film, the film tension is more preferably 300 N/m or more.

高溫高濕處理亦可兼作將聚乙烯醇系樹脂膜乾燥之處理、即降低其水分率之處理，只要不採用極端之高溫高濕條件，則通常同時進行乾燥處理。藉此，變得未必需要於高溫高濕處理之後另外實施乾燥處理，故與於絕對濕度未達40g/m³之高溫處理(乾燥處理)之後實施高溫高濕處理之先前之方法相比，於製造製程之簡略化及效率化之方面而言變得有利。 The high-temperature and high-humidity treatment can also be used as a treatment for drying the polyvinyl alcohol-based resin film, that is, a treatment for reducing the moisture content. As long as the extreme high-temperature and high-humidity conditions are not adopted, the drying treatment is usually performed simultaneously. As a result, it becomes unnecessary to perform a drying process after the high-temperature and high-humidity process, so compared with the previous method of performing the high-temperature and high-humidity process after the high-temperature process (drying process) with an absolute humidity of less than 40 g/m ³ , compared to It becomes advantageous in terms of simplification and efficiency of the manufacturing process.

供於高溫高濕處理之膜、即交聯步驟S30後或清洗步驟S40後之處於濕潤狀態之膜之水分率取決於膜之厚度，通常為13~50重量%左右。藉由高溫高濕處理獲得之水分率之降低程度，即高溫高濕處理前之水分率與高溫高濕處理後之水分率之差(水分率差ΔS)亦取決於膜之厚度，例如為5~45重量%，較佳為8~35重量%。例如於坯膜之厚度為40μm左右以下之情形時，水分率差ΔS可未達15重量%。 The moisture content of the film subjected to high temperature and high humidity treatment, that is, the film in the wet state after the cross-linking step S30 or after the cleaning step S40 depends on the thickness of the film, and is usually about 13 to 50% by weight. The degree of reduction of the moisture content obtained by the high-temperature and high-humidity treatment, that is, the difference between the moisture rate before the high-temperature and high-humidity treatment and the moisture rate after the high-temperature and high-humidity treatment (moisture rate difference ΔS) also depends on the thickness of the film, for example, 5 ~45 wt%, preferably 8~35 wt%. For example, when the thickness of the green film is about 40 μm or less, the difference in moisture content ΔS may not reach 15% by weight.

高溫高濕處理後之膜(於高溫高濕處理為最終步驟之情形時為偏光膜)之水分率亦取決於膜之厚度，通常為5~30重量%，就其後之膜之搬送性之觀點而言，較佳為6~15重量%。若水分率過低，則膜於搬送中容易破裂，又，若水分率過高，則由於放濕而容易於膜端部產 生捲縮。 The moisture content of the film after high-temperature and high-humidity treatment (the polarizing film when high-temperature and high-humidity treatment is the final step) also depends on the thickness of the film, usually 5 to 30% by weight, depending on the transportability of the subsequent film From a viewpoint, it is preferably 6 to 15% by weight. If the moisture content is too low, the film is likely to break during transportation, and if the moisture content is too high, it is easy to produce at the end of the film due to moisture release Raw curls.

總而言之，膜越薄，則水分越容易散逸，因此坯膜越薄，則高溫高濕處理前及高溫高濕處理中之水分率越容易降低。若水分率過低，則膜之搬送性容易降低。因此，於坯膜之厚度為40μm左右以下之情形時，將高溫高濕處理之溫度設定為較低，較佳為設為40~70℃。 In short, the thinner the film, the easier the water is to escape. Therefore, the thinner the green film, the easier it is to reduce the moisture content before and during the high-temperature and high-humidity treatment. If the moisture content is too low, the transportability of the film is likely to decrease. Therefore, when the thickness of the raw film is about 40 μm or less, the temperature of the high-temperature and high-humidity treatment is set to be low, preferably 40 to 70°C.

經歷以上步驟，能夠獲得使二色性色素吸附配向於經單軸延伸之聚乙烯醇系樹脂膜而成之偏光膜。偏光膜之厚度通常為5~40μm，較佳為30μm以下。根據藉由本發明獲得之偏光膜，即便於厚度較薄為30μm以下，進而25μm以下之情形時，由於MD收縮力較小，故亦能夠有效地抑制製成偏光板或液晶面板時之翹曲。 Through the above steps, a polarizing film obtained by aligning a dichroic dye with a polyvinyl alcohol resin film uniaxially stretched can be obtained. The thickness of the polarizing film is usually 5 to 40 μm, preferably 30 μm or less. According to the polarizing film obtained by the present invention, even when the thickness is as thin as 30 μm or less and further 25 μm or less, since the MD shrinkage force is small, it is possible to effectively suppress the warpage of the polarizing plate or the liquid crystal panel.

例如為了調整水分率，亦可於高溫高濕處理步驟S50之後實施乾燥處理(絕對濕度未達40g/m³時之高溫處理)。然而，由於可藉由高溫高濕處理步驟S50進行水分率之調整，故該乾燥處理為視需要進行者。 For example, in order to adjust the moisture content, drying treatment (high temperature treatment when the absolute humidity is less than 40 g/m ³ ) may be performed after the high temperature and high humidity treatment step S50. However, since the moisture content can be adjusted by the high-temperature and high-humidity treatment step S50, the drying treatment is performed as necessary.

所獲得之偏光膜例如亦可直接搬送至接下來之偏光板製作步驟(於偏光膜之單面或雙面貼合保護膜之步驟)。 For example, the obtained polarizing film can also be directly transferred to the next polarizing plate manufacturing step (a step of attaching a protective film on one side or both sides of the polarizing film).

一實施形態中，本發明之偏光膜係使二色性色素吸附配向於經單軸延伸之聚乙烯醇系樹脂膜而成之膜，可為藉由廣角X射線繞射(WAXD：Wide Angle X-ray Diffraction)之通過法測定的表示構成偏光膜之聚乙烯醇系樹脂於MD上之配向性之配向度(%)具有特徵者。藉由具有該特徵，推定本實施形態之偏光膜能夠表現如下特性、效果，即具有良好之光學特性但MD收縮力較小。 In one embodiment, the polarizing film of the present invention is a film formed by aligning a dichroic pigment with a polyvinyl alcohol resin film that is uniaxially stretched, and can be diffracted by wide-angle X-rays (WAXD: Wide Angle X -ray Diffraction) which is characterized by the degree of alignment (%) indicating the alignment of the polyvinyl alcohol-based resin constituting the polarizing film on the MD by the method. With this feature, it is presumed that the polarizing film of this embodiment can exhibit the following characteristics and effects, that is, it has good optical characteristics but has a small MD shrinkage force.

具體而言，關於本實施形態之偏光膜，於其厚度為20μm以上時，上述配向度較佳為71%以下，更佳為70%以下，進而較佳為67%以下。關於偏光膜之配向度，於其厚度為20μm以上時，通常為60% 以上，較佳為65%以上。厚度為20μm以上之偏光膜之厚度通常為30μm以下，較佳為25μm以下，又，較佳為22μm以上。 Specifically, regarding the polarizing film of the present embodiment, when the thickness is 20 μm or more, the alignment degree is preferably 71% or less, more preferably 70% or less, and further preferably 67% or less. The orientation of the polarizing film is usually 60% when its thickness is 20 μm or more The above is preferably 65% or more. The thickness of the polarizing film having a thickness of 20 μm or more is usually 30 μm or less, preferably 25 μm or less, and more preferably 22 μm or more.

關於本實施形態之偏光膜，於其厚度為10μm以上且未達20μm時，上述配向度較佳為74.0%以下，更佳為73%以下，進而較佳為72%以下。關於偏光膜之配向度，於其厚度為10μm以上且未達20μm時，通常為65%以上，較佳為70%以上。厚度為10μm以上且未達20μm之偏光膜之厚度較佳為15μm以下，更佳為13μm以下，又，較佳為11μm以上，更佳為12μm以上。 Regarding the polarizing film of the present embodiment, when the thickness is 10 μm or more and less than 20 μm, the alignment degree is preferably 74.0% or less, more preferably 73% or less, and still more preferably 72% or less. Regarding the degree of alignment of the polarizing film, when the thickness is 10 μm or more and less than 20 μm, it is usually 65% or more, preferably 70% or more. The thickness of the polarizing film having a thickness of 10 μm or more and less than 20 μm is preferably 15 μm or less, more preferably 13 μm or less, and further preferably 11 μm or more, more preferably 12 μm or more.

關於本實施形態之偏光膜，於其厚度未達10μm時，上述配向度較佳為75%以下，更佳為74%以下。關於偏光膜之配向度，於其厚度未達10μm時，通常為70%以上。厚度未達10μm之偏光膜之厚度通常為3μm以上，較佳為7μm以上，又，較佳為9μm以下。 Regarding the polarizing film of the present embodiment, when the thickness is less than 10 μm, the above-mentioned alignment degree is preferably 75% or less, and more preferably 74% or less. Regarding the degree of alignment of the polarizing film, when the thickness is less than 10 μm, it is usually 70% or more. The thickness of the polarizing film having a thickness of less than 10 μm is usually 3 μm or more, preferably 7 μm or more, and more preferably 9 μm or less.

顯示上述般之配向度之偏光膜可藉由上述本發明之偏光膜之製造方法而較佳地製造。此處所述之配向度係依照下述實施例之項所記載之方法測定。 The polarizing film exhibiting the above-mentioned alignment degree can be preferably produced by the above-mentioned method of manufacturing the polarizing film of the present invention. The degree of alignment described here is measured according to the method described in the following examples.

又，另一實施形態中，本發明之偏光膜係使二色性色素吸附配向於經單軸延伸之聚乙烯醇系樹脂膜而成之膜，可為表示偏光膜之基於交聯劑之交聯狀態的波數775cm^-1下之吸收軸方向之拉曼散射光強度與透射軸方向之拉曼散射光強度之比(以下亦稱為「拉曼散射光強度比」)具有特徵者。藉由具有該特徵，推定本實施形態之偏光膜能夠表現如下特性、效果，即具有良好之光學特性但MD收縮力較小。 Furthermore, in another embodiment, the polarizing film of the present invention is a film formed by aligning a dichroic dye with a uniaxially stretched polyvinyl alcohol-based resin film, which may be a cross-linking agent-based cross-section of the polarizing film. The ratio of the intensity of Raman scattered light in the absorption axis direction to the intensity of Raman scattered light in the transmission axis direction (hereinafter also referred to as "Raman scattered light intensity ratio") at a wave number of 775 cm ^{-1 in the} coupled state (hereinafter also referred to as "Raman scattered light intensity ratio") is characteristic. With this feature, it is presumed that the polarizing film of this embodiment can exhibit the following characteristics and effects, that is, it has good optical characteristics but has a small MD shrinkage force.

具體而言，關於本實施形態之偏光膜，上述拉曼散射光強度比較佳為0.86以上，更佳為0.89以上。拉曼散射光強度比通常為1.00以下，較佳為0.95以下。 Specifically, regarding the polarizing film of the present embodiment, the intensity of the Raman scattered light is relatively preferably 0.86 or more, and more preferably 0.89 or more. The Raman scattered light intensity ratio is usually 1.00 or less, preferably 0.95 or less.

顯示上述般之拉曼散射光強度比之偏光膜可藉由上述本發明之偏光膜之製造方法而較佳地製造。此處所述之拉曼散射光強度比係依 照下述實施例之項所記載之方法而測定。 The polarizing film showing the above-mentioned Raman scattered light intensity ratio can be preferably manufactured by the above-mentioned method of manufacturing the polarizing film of the present invention. The Raman scattered light intensity ratio described here depends on It was measured according to the method described in the following examples.

進而又一實施形態中，本發明之偏光膜係使二色性色素吸附配向於經單軸延伸之聚乙烯醇系樹脂膜而成之膜，顯示上述範圍內之配向度，且顯示上述範圍內之拉曼散射光強度比。於具有良好光學特性且減小MD收縮力之方面而言，較有利為顯示上述範圍內之配向度，且顯示上述範圍內之拉曼散射光強度比。 In still another embodiment, the polarizing film of the present invention is a film formed by aligning a dichroic dye with a uniaxially stretched polyvinyl alcohol-based resin film, showing the degree of alignment within the above range, and showing within the above range Raman scattered light intensity ratio. In terms of having good optical properties and reducing the MD shrinkage force, it is more advantageous to show the degree of alignment in the above range and also show the intensity ratio of Raman scattered light in the above range.

<偏光板> <polarizer>

可藉由將保護膜經由接著劑貼合(積層)於如以上般製造之、或顯示上述配向度及上述拉曼散射光強度比之至少一者之偏光膜之至少單面上而獲得偏光板。作為保護膜，可為包含熱塑性樹脂之透明樹脂膜，該熱塑性樹脂例如有：鏈狀聚烯烴系樹脂(聚丙烯系樹脂等)、環狀聚烯烴系樹脂(降

烯系樹脂等)般之聚烯烴系樹脂；三乙醯纖維素或二乙醯纖維素般之纖維素酯系樹脂；聚對苯二甲酸乙二酯、聚萘二甲酸乙二酯、聚對苯二甲酸丁二酯般之聚酯系樹脂；聚碳酸酯系樹脂；聚甲基丙烯酸甲酯系樹脂般之(甲基)丙烯酸系樹脂；或該等之混合物、共聚物等。 A polarizing plate can be obtained by attaching (laminating) a protective film via an adhesive to at least one side of a polarizing film manufactured as described above or showing at least one of the above-mentioned alignment degree and the above-mentioned Raman scattered light intensity ratio . As the protective film, it may be a transparent resin film containing a thermoplastic resin, and examples of the thermoplastic resin include: chain polyolefin resin (polypropylene resin, etc.), and cyclic polyolefin resin (downgrade

Vinyl resins, etc.) polyolefin resins; triacetyl cellulose or diethyl cellulose cellulose ester resins; polyethylene terephthalate, polyethylene naphthalate, polyethylene Polyester resins like butylene phthalate; polycarbonate resins; (meth)acrylic resins like polymethyl methacrylate resins; or mixtures and copolymers of these.

保護膜亦可為相位差膜、亮度提高膜般之一併具有光學功能之保護膜。例如，可藉由將包含上述材料之透明樹脂膜延伸(單軸延伸或雙軸延伸等)，或於該膜上形成液晶層等，而製成被賦予任意相位差值之相位差膜。 The protective film may also be one of retardation film, brightness enhancement film and the like with optical functions. For example, by extending a transparent resin film (uniaxial extension or biaxial extension, etc.) containing the above-mentioned materials, or forming a liquid crystal layer on the film, a retardation film having an arbitrary retardation value can be produced.

於保護膜之與偏光膜為相反側之表面上，亦可形成硬塗層、防眩層、抗反射層、抗靜電層、防污層般之表面處理層(塗佈層)。 A surface treatment layer (coating layer) like a hard coat layer, an anti-glare layer, an anti-reflection layer, an antistatic layer, and an anti-fouling layer can also be formed on the surface of the protective film opposite to the polarizing film.

就偏光板之薄型化之觀點而言，保護膜之厚度較佳為較薄，但若過薄，則強度降低，加工性較差，故較佳為5~150μm，更佳為5~100μm，進而較佳為10~50μm。 From the viewpoint of thinning the polarizing plate, the thickness of the protective film is preferably thin, but if it is too thin, the strength decreases and the workability is poor, so it is preferably 5 to 150 μm, more preferably 5 to 100 μm, and It is preferably 10 to 50 μm.

作為用於偏光膜與保護膜之貼合之接著劑，可列舉：紫外線硬 化性接著劑般之活性能量線硬化性接著劑、或聚乙烯醇系樹脂之水溶液、或者對其調配交聯劑而成之水溶液、胺基甲酸酯系乳液接著劑般之水系接著劑。於在偏光膜之雙面貼合保護膜之情形時，形成兩個接著劑層之接著劑可為相同種類，亦可為不同種類。例如，於在雙面貼合保護膜之情形時，亦可單面使用水系接著劑貼合，另一單面使用活性能量線硬化性接著劑貼合。紫外線硬化型接著劑可為自由基聚合性之(甲基)丙烯酸系化合物與光自由基聚合起始劑之混合物、或陽離子聚合性之環氧化合物與光陽離子聚合起始劑之混合物等。又，亦可併用陽離子聚合性之環氧化合物及自由基聚合性之(甲基)丙烯酸系化合物，且併用光陽離子聚合起始劑及光自由基聚合起始劑作為起始劑。 As an adhesive used for bonding the polarizing film and the protective film, ultraviolet hard It is an active energy ray-curable adhesive like a chemical adhesive, or an aqueous solution of a polyvinyl alcohol-based resin, or an aqueous solution prepared by blending a crosslinking agent thereto, and an aqueous adhesive like an urethane-based emulsion adhesive. In the case where the protective film is laminated on both sides of the polarizing film, the adhesives forming the two adhesive layers may be of the same type or different types. For example, in the case where the protective film is bonded on both sides, the water-based adhesive may be used for bonding on one side, and the active energy ray-curable adhesive may be used for bonding on the other side. The ultraviolet curing adhesive may be a mixture of a radically polymerizable (meth)acrylic compound and a photoradical polymerization initiator, or a mixture of a cationically polymerizable epoxy compound and a photocationic polymerization initiator. In addition, a cationic polymerizable epoxy compound and a radical polymerizable (meth)acrylic compound may be used in combination, and a photocationic polymerization initiator and a photoradical polymerization initiator may be used together as an initiator.

於使用活性能量線硬化性接著劑之情形時，藉由於貼合後照射活性能量線而使接著劑硬化。活性能量線之光源並無特別限定，較佳為於波長400nm以下具有發光分佈之活性能量線(紫外線)，具體而言，較佳地使用低壓水銀燈、中壓水銀燈、高壓水銀燈、超高壓水銀燈、化學燈、黑光燈、微波激發水銀燈、金屬鹵素燈等。 In the case of using an active energy ray-curable adhesive, the adhesive is hardened by irradiating the active energy ray after bonding. The light source of the active energy ray is not particularly limited, and it is preferably an active energy ray (ultraviolet) having a luminous distribution below 400 nm. Specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, Chemical lamp, black light lamp, microwave excited mercury lamp, metal halogen lamp, etc.

為了提高偏光膜與保護膜之接著性，亦可於偏光膜與保護膜之貼合前，對偏光膜及/或保護膜之貼合面實施電暈處理、火焰處理、電漿處理、紫外線照射處理、底塗劑塗佈處理、皂化處理等表面處理。 In order to improve the adhesion between the polarizing film and the protective film, the laminating surface of the polarizing film and/or the protective film may be subjected to corona treatment, flame treatment, plasma treatment, and ultraviolet irradiation before the polarizing film and the protective film are bonded Surface treatment such as treatment, primer coating treatment, saponification treatment, etc.

如上所述，本發明之偏光板亦可藉由於作為單層膜之偏光膜上貼合保護膜而製作，但並不限定於該方法，例如亦可藉由日本專利特開2009-98653號公報所記載之利用基材膜之方法製作。後者之方法對獲得具有薄膜之偏光膜(偏光元件層)之偏光板有利，例如可包含如下步驟。 As described above, the polarizing plate of the present invention can be produced by attaching a protective film to the polarizing film as a single-layer film, but it is not limited to this method, for example, Japanese Patent Laid-Open No. 2009-98653 It is produced by the method described using the base film. The latter method is advantageous for obtaining a polarizing plate having a thin-film polarizing film (polarizing element layer), and may include the following steps, for example.

樹脂層形成步驟，其於基材膜之至少一面上塗佈含有聚乙烯醇系樹脂之塗佈液後，進行乾燥，藉此形成聚乙烯醇系樹脂層而獲得積 層膜；延伸步驟，其使積層膜延伸而獲得延伸膜；染色步驟，其利用二色性色素將延伸膜之聚乙烯醇系樹脂層染色，形成偏光元件層(相當於偏光膜)，藉此獲得偏光性積層膜；第1貼合步驟，其使用接著劑將保護膜貼合於偏光性積層膜之偏光元件層上，獲得貼合膜；及剝離步驟，其將基材膜自貼合膜剝離去除，獲得附有單面保護膜之偏光板。 In the resin layer forming step, a coating solution containing a polyvinyl alcohol-based resin is applied to at least one side of the base film and then dried to form a polyvinyl alcohol-based resin layer to obtain a product A lamination film; an extension step, which extends the laminate film to obtain an extension film; a dyeing step, which uses a dichroic dye to dye the polyvinyl alcohol-based resin layer of the extension film to form a polarizing element layer (equivalent to a polarizing film), thereby Obtaining a polarizing laminate film; the first laminating step, which uses an adhesive to attach a protective film to the polarizing element layer of the polarizing laminate film to obtain a laminating film; and a peeling step, which is to attach the base film to the laminating film After peeling and removing, a polarizing plate with a single-sided protective film is obtained.

於在偏光元件層(偏光膜)之雙面積層保護膜之情形時，進而包含第2貼合步驟，其使用接著劑將保護膜貼合於附有單面保護膜之偏光板之偏光元件面。 In the case of the double-area protective film of the polarizing element layer (polarizing film), it further includes a second bonding step, which uses an adhesive to bond the protective film to the polarizing element surface of the polarizing plate with a single-sided protective film .

關於使用基材膜之上述方法，可於獲得偏光性積層膜之染色步驟(例如，獲得偏光性積層膜之染色步驟中之交聯步驟後或清洗步驟後)中包含高溫高濕處理步驟。上述偏光性積層膜、附有單面保護膜之偏光板、及經過第2貼合步驟而獲得之附有雙面保護膜之偏光板所含之偏光膜或自該等單離之偏光膜亦為屬於本發明之偏光膜，較佳為顯示上述範圍內之配向度及上述範圍內之拉曼散射光強度比之至少一者。 Regarding the above method using the base film, the high-temperature and high-humidity treatment step may be included in the dyeing step of obtaining the polarizing laminate film (for example, after the cross-linking step or after the washing step in the dyeing step of obtaining the polarizing laminate film). The polarizing film included in the above polarizing laminate film, the polarizing plate with a single-sided protective film, and the polarizing plate with a double-sided protective film obtained through the second laminating step or polarized films from these single-separated polarizing films are also The polarizing film belonging to the present invention preferably shows at least one of the degree of alignment in the above range and the intensity ratio of Raman scattered light in the above range.

[實施例] [Example]

以下，例示實施例進一步具體地說明本發明，但本發明並不受該等例之限定。 The following examples illustrate the present invention in further detail, but the present invention is not limited to these examples.

<實施例1> <Example 1>

將厚度60μm之長條之聚乙烯醇(PVA)坯膜[可樂麗股份有限公司製造之商品名「可樂麗聚乙烯醇膜VF-PE#6000」、平均聚合度2400、皂化度99.9莫耳%以上]一面自輥捲出一面連續地搬送，以滯留時間81秒浸漬於包含30℃之純水之膨潤浴(膨潤步驟)。其後，將自膨潤浴抽 出之膜以滯留時間143秒浸漬於碘化鉀/水為2/100(重量比)之含有碘之30℃之染色浴(染色步驟)。其次，將自染色浴抽出之膜以滯留時間67秒浸漬於碘化鉀/硼酸/水為12/4.1/100(重量比)之56℃之交聯浴，繼而，以滯留時間11秒浸漬於碘化鉀/硼酸/水為9/2.9/100(重量比)之40℃之交聯浴(交聯步驟)。於染色步驟及交聯步驟中，藉由浴中之輥間延伸進行縱單軸延伸。以坯膜為基準之總延伸倍率設為5.7倍。 A long strip of polyvinyl alcohol (PVA) blank film with a thickness of 60 μm [trade name "Kuraray Polyvinyl Alcohol Film VF-PE#6000" manufactured by Kuraray Co., Ltd.), average polymerization degree 2400, saponification degree 99.9 mole% The above] is continuously conveyed while being rolled out from the roll, and immersed in a swelling bath containing pure water at 30°C for a residence time of 81 seconds (swelling step). Thereafter, the self-swelling bath is pumped The resulting film was immersed in a dyeing bath containing iodine at 30°C containing potassium iodide/water of 2/100 (weight ratio) with a residence time of 143 seconds (dyeing step). Next, the film extracted from the dyeing bath was immersed in a crosslinking bath of 56° C. with potassium iodide/boric acid/water of 12/4.1/100 (weight ratio) at a residence time of 67 seconds, and then immersed in potassium iodide/ at a residence time of 11 seconds. Boric acid/water is 9/2.9/100 (weight ratio) at 40°C crosslinking bath (crosslinking step). In the dyeing step and the cross-linking step, longitudinal uniaxial stretching is performed by stretching between the rollers in the bath. The total stretch ratio based on the green film was set to 5.7 times.

其次，將自交聯浴抽出之膜以滯留時間3秒浸漬於包含5℃之純水之清洗浴後(清洗步驟)，繼而，導入至可調節濕度之第1加熱爐，藉此以滯留時間161秒進行高溫高濕處理(高溫高濕處理步驟)，獲得厚度22.9μm、寬度207mm之偏光膜。第1加熱爐內之溫度、絕對濕度分別設為80℃、88g/m³，高溫高濕處理時之膜張力設為565N/m。即將進行第1加熱爐導入(高溫高濕處理)之前、剛進行第1加熱爐導入(高溫高濕處理)後之膜之水分率分別為33.3重量%、7.9重量%，水分率差ΔS為25.4重量%。 Next, the film drawn from the crosslinking bath was dipped in a clean bath containing pure water at 5°C for a residence time of 3 seconds (washing step), and then introduced into the first heating furnace with adjustable humidity, whereby the residence time was 161 A high-temperature and high-humidity treatment (high-temperature and high-humidity treatment step) was performed in seconds to obtain a polarizing film having a thickness of 22.9 μm and a width of 207 mm. The temperature and absolute humidity in the first heating furnace were set at 80°C and 88 g/m ³ , respectively, and the film tension during the high-temperature and high-humidity treatment was set at 565 N/m. The moisture content of the film immediately before the introduction of the first heating furnace (high temperature and high humidity treatment) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment) were 33.3% by weight and 7.9% by weight, respectively, and the water content difference ΔS was 25.4 weight%.

<實施例2> <Example 2>

將第1加熱爐內之溫度及絕對濕度、以及藉由第1加熱爐之處理時之膜張力變更為如表1所示，除此以外，以與實施例1相同之方式製作厚度23.7μm、寬度200mm之偏光膜。 The temperature and the absolute humidity in the first heating furnace and the film tension during the processing in the first heating furnace were changed to those shown in Table 1, except that the thickness was 23.7 μm in the same manner as in Example 1. Polarizing film with a width of 200mm.

<比較例1> <Comparative Example 1>

將第1加熱爐內之溫度及絕對濕度、以及藉由第1加熱爐進行處理時之膜張力變更為如表1所示，除此以外，以與實施例1相同之方式製作厚度23.2μm、寬度206mm之偏光膜。第1加熱爐內之溫度、絕對濕度分別為76℃、8g/m³，於第1加熱爐中不進行高溫高濕處理，而僅進行加熱(乾燥)處理。 The temperature and the absolute humidity in the first heating furnace, and the film tension when processed by the first heating furnace were changed to those shown in Table 1, except that the thickness was 23.2 μm in the same manner as in Example 1. Polarizing film with a width of 206mm. The temperature and absolute humidity in the first heating furnace were 76° C. and 8 g/m ³ , respectively, and the high-temperature and high-humidity treatment was not performed in the first heating furnace, but only the heating (drying) treatment.

<比較例2> <Comparative Example 2>

利用溫度、絕對濕度分別為76℃、8g/m³之第1加熱爐進行加熱 (乾燥)處理後，進而導入至另一可調節濕度之第2加熱爐，藉此以滯留時間161秒進行高溫高濕處理，除此以外，以與比較例1相同之方式製作厚度23.4μm、寬度208mm之偏光膜。第2加熱爐內之溫度、絕對濕度分別設為80℃、88g/m³，利用第2加熱爐進行高溫高濕處理時之膜張力設為2N/m。 After heating (drying) the first heating furnace with a temperature and absolute humidity of 76°C and 8g/m ³ , respectively, it is then introduced into another second heating furnace with adjustable humidity, thereby allowing high temperature with a residence time of 161 seconds Except for the high humidity treatment, a polarizing film having a thickness of 23.4 μm and a width of 208 mm was produced in the same manner as in Comparative Example 1. The temperature and the absolute humidity in the second heating furnace were set to 80°C and 88 g/m ³ , respectively, and the film tension during the high-temperature and high-humidity treatment by the second heating furnace was set to 2 N/m.

<比較例3> <Comparative Example 3>

將第2加熱爐內之溫度及絕對濕度變更為如表1所示，除此以外，以與比較例2相同之方式製作厚度23.3μm、寬度207mm之偏光膜。 A polarizing film having a thickness of 23.3 μm and a width of 207 mm was prepared in the same manner as in Comparative Example 2 except that the temperature and absolute humidity in the second heating furnace were changed as shown in Table 1.

<實施例3> <Example 3>

將厚度30μm之長條之聚乙烯醇(PVA)坯膜[可樂麗股份有限公司製造之商品名「可樂麗聚乙烯醇膜VF-PE#3000」、平均聚合度2400、皂化度99.9莫耳%以上]一面自輥捲出一面連續地搬送，以滯留時間31秒浸漬於包含20℃之純水之膨潤浴中(膨潤步驟)。其後，將自膨潤浴抽出之膜以滯留時間122秒浸漬於碘化鉀/水為2/100(重量比)之含有碘之30℃之染色浴(染色步驟)。其次，將自染色浴抽出之膜以滯留時間70秒浸漬於碘化鉀/硼酸/水為12/4.1/100(重量比)之56℃之交聯浴，繼而，以滯留時間13秒浸漬於碘化鉀/硼酸/水為9/2.9/100(重量比)之40℃之交聯浴(交聯步驟)。於染色步驟及交聯步驟中，藉由浴中之輥間延伸進行縱單軸延伸。以坯膜為基準之總延伸倍率設為5.4倍。 A long strip of polyvinyl alcohol (PVA) blank film with a thickness of 30 μm [trade name "Kuraray Polyvinyl Alcohol Film VF-PE#3000" manufactured by Kuraray Co., Ltd.), average polymerization degree 2400, saponification degree 99.9 mole% Above] Continuously conveyed while being rolled out from the roll, and immersed in a swelling bath containing pure water at 20°C for a residence time of 31 seconds (swelling step). Thereafter, the film drawn from the swelling bath was immersed in a dye bath of 30° C. containing iodine with a potassium iodide/water ratio of 2/100 (weight ratio) at a residence time of 122 seconds (dyeing step). Next, the film drawn from the dyeing bath was immersed in a 56°C cross-linking bath of potassium iodide/boric acid/water of 12/4.1/100 (weight ratio) at a residence time of 70 seconds, and then immersed in potassium iodide/ at a residence time of 13 seconds Boric acid/water is 9/2.9/100 (weight ratio) at 40°C crosslinking bath (crosslinking step). In the dyeing step and the cross-linking step, longitudinal uniaxial stretching is performed by stretching between the rollers in the bath. The total stretch ratio based on the green film was set to 5.4 times.

其次，將自交聯浴抽出之膜以滯留時間3秒浸漬於包含5℃之純水之清洗浴後(清洗步驟)，繼而，導入至可調節濕度之第1加熱爐，藉此以滯留時間190秒進行高溫高濕處理(高溫高濕處理步驟)，獲得厚度12.1μm、寬度208mm之偏光膜。第1加熱爐內之溫度、絕對濕度分別設為73℃、89g/m³，高溫高濕處理時之膜張力設為601N/m。即將進行第1加熱爐導入(高溫高濕處理)之前、剛進行第1加熱爐導入(高 溫高濕處理)後之膜之水分率分別為19.4重量%、8.0重量%，水分率差ΔS為11.4重量%。 Next, the film drawn from the crosslinking bath was immersed in a clean bath containing pure water at 5°C for a residence time of 3 seconds (washing step), and then introduced into the first heating furnace with adjustable humidity, whereby the residence time was 190 A high-temperature and high-humidity treatment (high-temperature and high-humidity treatment step) was performed in seconds to obtain a polarizing film with a thickness of 12.1 μm and a width of 208 mm. The temperature and the absolute humidity in the first heating furnace were set to 73°C and 89g/m ³ , respectively, and the film tension during the high-temperature and high-humidity treatment was set to 601N/m. The moisture content of the film immediately before the introduction of the first heating furnace (high temperature and high humidity treatment) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment) were 19.4% by weight and 8.0% by weight, respectively, and the water content difference ΔS was 11.4 weight%.

<實施例4~8> <Examples 4-8>

將第1加熱爐內之溫度及絕對濕度、以及藉由第1加熱爐進行高溫高濕處理時之膜張力變更為如表1所示，除此以外，以與實施例3相同之方式製作偏光膜。 Polarized light was produced in the same manner as in Example 3 except that the temperature and absolute humidity in the first heating furnace and the film tension during the high temperature and high humidity treatment in the first heating furnace were changed as shown in Table 1. membrane.

<比較例4> <Comparative Example 4>

將第1加熱爐內之溫度及絕對濕度、以及藉由第1加熱爐進行處理時之膜張力變更為如表1所示，除此以外，以與實施例3相同之方式製作厚度12.5μm、寬度203mm之偏光膜。第1加熱爐內之溫度、絕對濕度分別為60℃、12g/m³，於第1加熱爐中不進行高溫高濕處理，僅進行加熱(乾燥)處理。 The temperature and the absolute humidity in the first heating furnace, and the film tension when processed in the first heating furnace were changed to those shown in Table 1, except that the thickness was 12.5 μm in the same manner as in Example 3. Polarizing film with a width of 203mm. The temperature and absolute humidity in the first heating furnace were 60° C. and 12 g/m ³ , respectively. The first heating furnace was not subjected to high-temperature and high-humidity treatment, but only heating (drying) treatment.

<比較例5> <Comparative Example 5>

利用溫度、絕對濕度分別為59℃、10g/m³之第1加熱爐進行加熱(乾燥)處理後，進而導入至另一可調節濕度之第2加熱爐，藉此以滯留時間161秒進行高溫高濕處理，及將藉由第1加熱爐進行處理時之膜張力變更為如表1所示，除此以外，以與比較例4相同之方式製作厚度12.9μm、寬度204mm之偏光膜。第2加熱爐內之溫度、絕對濕度分別設為73℃、89g/m³，利用第2加熱爐進行高溫高濕處理時之膜張力設為1N/m。 After heating (drying) the first heating furnace with a temperature and absolute humidity of 59°C and 10g/m ³ , respectively, it is then introduced into another second heating furnace with adjustable humidity, where the residence time is 161 seconds for high temperature The high-humidity treatment and the film tension in the first heating furnace were changed to those shown in Table 1, except that a polarizing film having a thickness of 12.9 μm and a width of 204 mm was produced in the same manner as in Comparative Example 4. The temperature and absolute humidity in the second heating furnace were set to 73° C. and 89 g/m ³ , respectively, and the film tension during the high-temperature and high-humidity treatment by the second heating furnace was set to 1 N/m.

將各實施例及比較例之偏光膜之製造條件、即將進行第1加熱爐導入(高溫高濕處理)之前及剛進行第1加熱爐導入(高溫高濕處理)後之膜之水分率、以及作為該等之差之水分率差ΔS彙總於表1。 The manufacturing conditions of the polarizing films of each example and comparative example, the moisture content of the film immediately before the introduction of the first heating furnace (high temperature and high humidity treatment) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment), and The water content difference ΔS as these differences is summarized in Table 1.

再者，加熱爐內之絕對濕度係根據爐內溫度及相對濕度之測定值算出。所獲得之偏光膜之厚度係使用Nikon股份有限公司製造之數位式測微計「MH-15M」測定。又，膜(偏光膜)之水分率係藉由如下 方法求出。 In addition, the absolute humidity in the heating furnace is calculated based on the measured values of the temperature and relative humidity in the furnace. The thickness of the obtained polarizing film was measured using a digital micrometer "MH-15M" manufactured by Nikon Corporation. Also, the moisture content of the film (polarizing film) is as follows Method.

預先使用水分率不同之複數個偏光膜試樣，將表示利用乾燥重量法獲得之水分率與紅外線吸收式之水分計(Fujiwork股份有限公司製造之「IM 3SCV MODEL-1900L」)之測定值之相關之校準曲線(換算式)如下式：使用厚度60μm之PVA原片之偏光膜之情形：利用乾燥重量法獲得之水分率(重量%)=0.0600×(水分計測定值)-50.0252 A plurality of polarizing film samples with different moisture rates are used in advance, and the correlation between the moisture rate obtained by the dry weight method and the measured value of an infrared absorption type moisture meter ("IM 3SCV MODEL-1900L" manufactured by Fujiwork Co., Ltd.) is shown. The calibration curve (conversion formula) is as follows: When the polarizing film of the PVA original film with a thickness of 60 μm is used: Moisture rate (weight %) obtained by dry weight method = 0.0600 × (measured value of moisture meter)-50.0252

使用厚度30μm之PVA原片之偏光膜之情形：利用乾燥重量法獲得之水分率(重量%)=0.0495×(水分計測定值)-38.8379求出。此時，關於藉由乾燥重量法獲得之水分率，於將以105℃乾燥2小時之時之偏光膜之重量設為W1、將乾燥前之偏光膜之重量設為W0時，依照下式：藉由乾燥重量法獲得之水分率(重量%)={(W0-W1)÷W0}×100求出。表1所記載之水分率為使用上述水分計獲得測定值，將其代入上述校準曲線(換算式)中，換算為利用乾燥重量法獲得之水分率(重量%)而得者。藉由自即將導入至第1加熱爐前之水分率減去剛導入後之水分率，算出水分率差ΔS。 When using the polarizing film of the PVA original film with a thickness of 30 μm: the moisture content (weight %) obtained by the dry gravimetric method = 0.0495 × (measured value by moisture meter)-38.8379. At this time, regarding the moisture content obtained by the dry weight method, when the weight of the polarizing film when dried at 105°C for 2 hours is set to W1, and the weight of the polarizing film before drying is set to W0, the following formula is used: The moisture content (weight %) obtained by the dry weight method = {(W0-W1) ÷ W0} × 100 is obtained. The moisture content described in Table 1 was obtained by using the moisture meter to obtain the measured value, and substituting it into the calibration curve (conversion formula) to obtain the moisture content (weight %) obtained by the dry weight method. The moisture rate difference ΔS is calculated by subtracting the moisture rate immediately after introduction from the moisture rate immediately before introduction into the first heating furnace.

[偏光膜之評價] [Evaluation of polarizing film]

關於下述項目，測定由各實施例及比較例所獲得之偏光膜之特性。將結果示於表1。 Regarding the following items, the characteristics of the polarizing films obtained in the examples and comparative examples were measured. The results are shown in Table 1.

(1)可見度修正單體透過率(Ty)及可見度修正偏光度(Py) (1) Visibility correction monomer transmittance (Ty) and visibility correction polarization (Py)

就所獲得之偏光膜，使用附有積分球之分光光度計[日本分光股份有限公司製造之「V7100」]測定波長380~780nm之範圍之MD透過率及TD透過率，基於下述式：單體透過率(%)=(MD+TD)/2 For the obtained polarizing film, use a spectrophotometer with an integrating sphere ["V7100" manufactured by Japan Spectroscopy Co., Ltd.] to measure the MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm based on the following formula: single Body transmittance (%)=(MD+TD)/2

偏光度(%)={(MD-TD)/(MD+TD)}×100算出各波長下之單體透過率及偏光度。 Polarization (%)={(MD-TD)/(MD+TD)}×100 Calculate the monomer transmittance and polarization at each wavelength.

所謂「MD透過率」，係使自葛蘭-湯普生稜鏡射出之偏光之朝向與偏光膜試樣之透射軸平行時之透過率，上述式中表示為「MD」。又，所謂「TD透過率」，係使自葛蘭-湯普生稜鏡射出之偏光之朝向與偏光膜試樣之透射軸正交時之透過率，上述式中表示為「TD」。關於所獲得之單體透過率及偏光度，係根據JIS Z 8701：1999「色之表示方法-XYZ表色系及X₁₀Y₁₀Z₁₀表色系」之2度視野(C光源)進行可見度修正，求出可見度修正單體透過率(Ty)及可見度修正偏光度(Py)。 The so-called "MD transmittance" refers to the transmittance when the direction of polarized light emitted from Gülen-Thompson Arachis is parallel to the transmission axis of the polarizing film sample, and is expressed as "MD" in the above formula. In addition, the "TD transmittance" is the transmittance when the direction of the polarized light emitted from Gülen-Thompson Arachis is orthogonal to the transmission axis of the polarizing film sample, and is expressed as "TD" in the above formula. The transmittance and polarized degree of the obtained monomer are based on JIS Z 8701: 1999 "Color representation method-XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ system color system" 2 degree field of view (C light source) for visibility For correction, the visibility correction monomer transmittance (Ty) and the visibility correction polarization (Py) are obtained.

(2)MD收縮力 (2) MD contraction force

自所獲得之偏光膜切出將吸收軸方向(MD、延伸方向)作為長邊之寬2mm、長10mm之測定用試樣。將該試樣設置於SII NanoTechnology股份有限公司製造之熱機械分析裝置(TMA)「EXSTAR-6000」，將尺寸保持為一定不變，測定於80℃下保持4小時之時產生之長邊方向(吸收軸方向、MD)之收縮力(MD收縮力)。 From the obtained polarizing film, a measurement sample having a width of 2 mm and a length of 10 mm with the absorption axis direction (MD, extension direction) as the long side was cut out. The sample was installed in the thermal mechanical analysis device (TMA) "EXSTAR-6000" manufactured by SII NanoTechnology Co., Ltd., the dimensions were kept constant, and the long-side direction generated when kept at 80°C for 4 hours was measured ( Absorb the contraction force (MD contraction force) of the axis direction, MD).

(3)配向度 (3) Alignment

由廣角X射線繞射(WAXD：Wide Angle X-ray Diffraction)之通過法求出表示構成偏光膜之聚乙烯醇系樹脂於MD上之配向性之「配向度」。首先，自所獲得之偏光膜切出複數片將吸收軸方向(MD、延伸方向)作為長邊之長方形之膜。將切出之膜以該等之MD(長邊)成為平行之方式重疊複數片並固定，將其作為測定用試樣。測定用試樣之厚度設為0.1mm左右。使用下述X射線繞射裝置，自相對於測定用試樣之表面垂直之方向，以下述X射線輸出條件將X射線照射至測定用試樣之一表面，拍攝利用透過法之繞射像。 The "alignment degree" indicating the alignment of the polyvinyl alcohol-based resin constituting the polarizing film on the MD is obtained by the wide angle X-ray diffraction (WAXD: Wide Angle X-ray Diffraction) pass method. First, a plurality of rectangular films were cut out from the obtained polarizing film with the absorption axis direction (MD, extension direction) as the long side. The cut film was superposed and fixed so that the MD (long side) became parallel, and this was used as a measurement sample. The thickness of the sample for measurement is set to about 0.1 mm. Using the following X-ray diffraction device, X-rays were irradiated to the surface of one of the measurement samples under the following X-ray output conditions from a direction perpendicular to the surface of the measurement sample, and a diffraction image by the transmission method was taken.

X射線繞射裝置：Rigaku股份有限公司製造之「NANO-Viewer」、 X射線輸出條件：Cu靶、40kV、20mA。 X-ray diffraction device: "NANO-Viewer" manufactured by Rigaku Corporation, X-ray output conditions: Cu target, 40kV, 20mA.

根據所獲得之繞射像，關於繞射角度2θ=20°附近之峰，藉由將2θ=19.5~20.5°之範圍進行圓環積分，首先算出未修正方位角分佈曲線(方位角度(β角度)-強度分佈曲線)。所謂未修正方位角分佈曲線，意指實施基底修正(background correction)前之方位角分佈曲線。其次，自X射線之光軸上取下測定用試樣，除此以外，以相同條件進行測定，算出方位角分佈曲線之基底。進行透過率修正後，自上述未修正方位角分佈曲線去除基底，獲得基底修正後之方位角分佈曲線(以下亦簡稱為「方位角分佈曲線」)。圖2係表示基底修正後之方位角分佈曲線之一例之圖。該方位角分佈曲線之峰為配向性峰，本測定中，將測定用試樣之MD設置為鉛垂方向，將出現於水平方向上之配向性峰之最大強度下之β角度設為0°。配向性峰之最大強度下之β角度(0°及180°)源自配向於偏光膜之MD之成分。根據所獲得之方位角分佈曲線，依照下述式：配向度(%)=(360-W)/360求出配向度。W為於將方位角分佈曲線之峰總體之積分值設為100%時，對所有配向性峰求出積分值成為50%之峰全寬時之該等之和。上述峰全寬之中心位置(°)與峰顯示最大強度之β角度(°)一致。 According to the obtained diffraction image, about the peak around the diffraction angle 2θ=20°, by integrating the range of 2θ=19.5~20.5°, the uncorrected azimuth distribution curve (azimuth angle (β angle )-Intensity distribution curve). The so-called uncorrected azimuth distribution curve means the azimuth distribution curve before background correction. Next, the measurement sample was removed from the X-ray optical axis, and the measurement was performed under the same conditions to calculate the base of the azimuth distribution curve. After the transmittance correction is performed, the base is removed from the above uncorrected azimuth distribution curve to obtain the base-corrected azimuth distribution curve (hereinafter also simply referred to as "azimuth distribution curve"). FIG. 2 is a diagram showing an example of the azimuth distribution curve after base correction. The peak of the azimuth distribution curve is an alignment peak. In this measurement, the MD of the measurement sample is set in the vertical direction, and the β angle at the maximum intensity of the alignment peak appearing in the horizontal direction is set to 0°. The β angle (0° and 180°) at the maximum intensity of the alignment peak is derived from the component of the MD aligned to the polarizing film. According to the obtained azimuth distribution curve, according to the following formula: Alignment degree (%)=(360-W)/360 Calculate the alignment degree. W is the sum of the total width of the peak when the integral value of the peak of the azimuth distribution curve is set to 100% for all the directional peaks, and the integral value becomes 50% of the full width of the peak. The center position (°) of the full width of the above peak coincides with the β angle (°) of the peak showing the maximum intensity.

(4)拉曼散射光強度比 (4) Raman scattered light intensity ratio

為了求出所獲得之偏光膜之拉曼散射光強度比，染色浴不含碘，除此以外，以與各實施例及各比較例相同之方式製作分析用膜。確認所獲得之偏光膜之拉曼散射光強度比與該分析用膜之拉曼散射光強度比相同。 In order to obtain the Raman scattered light intensity ratio of the obtained polarizing film, the dyeing bath did not contain iodine, and the analysis film was prepared in the same manner as in each example and each comparative example except that the dyeing bath did not contain iodine. It was confirmed that the intensity ratio of Raman scattered light of the obtained polarizing film was the same as the intensity ratio of Raman scattered light of the film for analysis.

關於所獲得之分析用膜，使用日本分光股份有限公司製造之雷射拉曼分光光度計「NRS-5100」，依照下述式：拉曼散射光強度比=(波數775cm^-1下之分析用膜之延伸方向之拉 曼散射光強度)/(波數775cm^-1下之分析用膜之與延伸方向正交之方向之拉曼散射光強度)求出波數775cm^-1下之吸收軸方向之拉曼散射光強度與透射軸方向之拉曼散射光強度之比(拉曼散射光強度比)，將其作為所獲得之偏光膜之拉曼散射光強度比。 Regarding the obtained analysis film, a laser Raman spectrophotometer "NRS-5100" manufactured by Japan Spectroscopy Co., Ltd. was used, according to the following formula: Raman scattered light intensity ratio = (analysis at wave number 775cm ^-1 Raman scattered light intensity of Raman scattered light intensity) / (wave number of 775cm extending direction of the film orthogonal to the direction of analysis of the film under the extending direction of ^-1) to obtain a wavenumber of 775cm ^-1 absorption axis The ratio of the intensity of the Raman scattered light in the direction to the intensity of the Raman scattered light in the transmission axis direction (Raman scattered light intensity ratio) was used as the ratio of the intensity of the Raman scattered light of the obtained polarizing film.

此處，波數775cm^-1下之分析用膜之延伸方向之拉曼散射光強度係使雷射光以雷射光之偏光面與分析用膜之延伸方向成為平行之方式自分析用膜表面垂直地入射，使析光片之偏光面與雷射光之偏光面成為平行而測定。同樣地，波數775cm^-1下之分析用膜之與延伸方向正交之方向之拉曼散射光強度係使雷射光以雷射光之偏光面與分析用膜之延伸方向正交之方式自分析用膜表面垂直地入射，使析光片之偏光面與雷射光之偏光面成為平行而測定。 Here, the Raman scattered light intensity of the extension direction of the analysis film at a wave number of 775 cm ^-1 is such that the laser light is perpendicular to the surface of the analysis film so that the polarization plane of the laser light and the extension direction of the analysis film become parallel Incidentally, the polarizing surface of the light analysis sheet and the polarizing surface of the laser light are parallel and measured. Similarly, the intensity of Raman scattered light in the direction orthogonal to the extension direction of the analysis film at a wave number of 775 cm ^-1 is such that the laser light is self-analyzed in such a way that the polarization plane of the laser light is orthogonal to the extension direction of the analysis film The film surface is perpendicularly incident so that the polarizing surface of the light-separating sheet and the polarizing surface of the laser light are parallel and measured.

用於上述拉曼分光測定之條件如以下所述。 The conditions for the above-mentioned Raman spectrometry are as follows.

‧激發波長：532nm、‧光柵：600l/mm、‧狹縫寬：100×1000μm、‧孔徑：

40μm、‧物鏡：100倍。 ‧Excitation wavelength: 532nm, ‧Grating: 600l/mm, ‧Slit width: 100×1000μm, ‧Aperture:

40μm, ‧objective lens: 100 times.

<實施例9> <Example 9>

將厚度20μm之長條之聚乙烯醇(PVA)坯膜[可樂麗股份有限公司製造之商品名「可樂麗聚乙烯醇膜VF-PE#2000」、平均聚合度2400、皂化度99.9莫耳%以上]一面自輥捲出一面連續地搬送，以乾式單軸延伸為4.1倍，進而保持為拉伸狀態不變，以滯留時間50秒浸漬於包含30℃之純水之膨潤浴中(膨潤步驟)。其後，將自膨潤浴抽出之膜以滯留時間88秒浸漬於碘化鉀/水為5/100(重量比)之含有碘之30℃之染色浴(染色步驟)。其次，將自染色浴抽出之膜以滯留時間115秒浸漬於碘化鉀/硼酸/水為18/5.6/100(重量比)之65℃之交聯浴(交聯步驟)。於染色步驟及交聯步驟中，藉由浴中之輥間延伸進一步進行縱單軸延伸。以坯膜為基準之總延伸倍率設為4.3倍。 A long strip of polyvinyl alcohol (PVA) blank film with a thickness of 20 μm [trade name "Kuraray Polyvinyl Alcohol Film VF-PE#2000" manufactured by Kuraray Co., Ltd.), average polymerization degree 2400, saponification degree 99.9 mole% Above] Continuously conveyed while being rolled out from the roll, stretched 4.1 times in a dry uniaxial direction, and then maintained in a stretched state, immersed in a swelling bath containing pure water at 30°C for a residence time of 50 seconds (swelling step ). Thereafter, the film drawn from the swelling bath was immersed in a dyeing bath containing potassium iodide/water of 5/100 (weight ratio) at 30° C. containing iodine at a residence time of 88 seconds (dyeing step). Next, the film drawn from the dyeing bath was immersed in a crosslinking bath of 65° C. with a potassium iodide/boric acid/water ratio of 18/5.6/100 (weight ratio) at a residence time of 115 seconds (crosslinking step). In the dyeing step and the cross-linking step, longitudinal uniaxial stretching is further performed by stretching between rolls in the bath. The total stretch ratio based on the green film was set to 4.3 times.

其次，將自交聯浴抽出之膜以滯留時間7秒浸漬於包含4℃之純水之清洗浴後(清洗步驟)，繼而，藉由導入至可調節濕度之第1加熱爐，以滯留時間97秒進行高溫高濕處理(高溫高濕處理步驟)，獲得厚度8.1μm、寬度216mm之偏光膜。第1加熱爐內之溫度、絕對濕度分別設為71℃、135g/m³，高溫高濕處理時之膜張力設為208N/m。即將進行第1加熱爐導入(高溫高濕處理步驟)之前、剛進行第1加熱爐導入(高溫高濕處理步驟)後之膜之水分率分別為15.5重量%、9.7重量%，水分率差ΔS為5.8重量%。 Next, after immersing the film drawn from the crosslinking bath in a clean bath containing pure water at 4°C for a residence time of 7 seconds (washing step), then, by introducing it into the first heating furnace with adjustable humidity, the residence time is 97 A high-temperature and high-humidity treatment (high-temperature and high-humidity treatment step) was performed in seconds to obtain a polarizing film with a thickness of 8.1 μm and a width of 216 mm. The temperature and absolute humidity in the first heating furnace were set to 71°C and 135g/m ³ , respectively, and the film tension during the high-temperature and high-humidity treatment was set to 208N/m. The moisture content of the film immediately before the introduction of the first heating furnace (high temperature and high humidity treatment step) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment step) were 15.5% by weight and 9.7% by weight, respectively, and the water content difference was ΔS It is 5.8% by weight.

<比較例6> <Comparative Example 6>

將第1加熱爐內之溫度及絕對濕度、以及藉由第1加熱爐進行高溫高濕處理時之膜張力變更為如表2所示，除此以外，以與實施例9相同之方式製作偏光膜。 Polarized light was produced in the same manner as in Example 9 except that the temperature and absolute humidity in the first heating furnace and the film tension during the high-temperature and high-humidity treatment in the first heating furnace were changed as shown in Table 2. membrane.

將實施例9及比較例6之偏光膜之製造條件、即將進行第1加熱爐導入(高溫高濕處理)之前及剛進行第1加熱爐導入(高溫高濕處理)後之膜之水分率、以及作為該等之差之水分率差ΔS彙總於表2。又，就上 述項目測定實施例9及比較例6之偏光膜之特性。將結果示於表2。 The manufacturing conditions of the polarizing films of Example 9 and Comparative Example 6, that is, the moisture content of the film immediately before the introduction of the first heating furnace (high temperature and high humidity treatment) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment), The water content difference ΔS, which is the difference, is summarized in Table 2. Again, just go The items described above measured the characteristics of the polarizing films of Example 9 and Comparative Example 6. The results are shown in Table 2.

<實施例10> <Example 10>

(1)基材膜之製作 (1) Fabrication of substrate film

藉由使用多層擠出成形機之共擠出成形製作於包含含有乙烯單元約5重量%之丙烯/乙烯之無規共聚物(住友化學股份有限公司製造之商品名「住友Noblen W151」、熔點Tm=138℃)之樹脂層之兩側配置有包含作為丙烯之均聚物之均聚丙烯(住友化學股份有限公司製造之商品名「住友Noblen FLX80E4」、熔點Tm=163℃)之樹脂層之3層構造之基材膜。所獲得之基材膜之合計之厚度為100μm，各層之厚度比 (FLX80E4/W151/FLX80E4)為3/4/3。 By co-extrusion molding using a multi-layer extrusion molding machine, a random copolymer containing propylene/ethylene containing about 5 wt% of ethylene units (trade name "Sumitomo Noblen W151" manufactured by Sumitomo Chemical Co., Ltd., melting point Tm) = 138°C) on both sides of the resin layer, 3 of the resin layer containing homopolypropylene as a homopolymer of propylene (trade name "Sumitomo Noblen FLX80E4" manufactured by Sumitomo Chemical Co., Ltd., melting point Tm=163°C) The base film of the layer structure. The total thickness of the obtained base film is 100 μm, and the thickness ratio of each layer (FLX80E4/W151/FLX80E4) is 3/4/3.

(2)底塗層形成用塗佈液之製備 (2) Preparation of coating liquid for forming undercoat layer

將聚乙烯醇粉末(日本合成化學工業股份有限公司製造之商品名「Z-200」、平均聚合度1100、皂化度99.5莫耳%)溶解於95℃之熱水，製備濃度3重量%之聚乙烯醇水溶液。將交聯劑(田岡化學工業股份有限公司製造之商品名「Sumirez Resin 650」)以相對於聚乙烯醇粉末2重量份為1重量份之比率混合於所獲得之水溶液，獲得底塗層形成用塗佈液。 Polyvinyl alcohol powder (trade name "Z-200" manufactured by Japan Synthetic Chemical Industry Co., Ltd., average degree of polymerization 1100, degree of saponification 99.5 mol%) was dissolved in hot water at 95°C to prepare a polymer with a concentration of 3% by weight Vinyl alcohol aqueous solution. A crosslinking agent (trade name "Sumirez Resin 650" manufactured by Taoka Chemical Industry Co., Ltd.) was mixed with the obtained aqueous solution at a ratio of 1 part by weight with respect to 2 parts by weight of the polyvinyl alcohol powder to obtain an undercoat layer. Coating liquid.

(3)聚乙烯醇系樹脂層形成用塗佈液之製備 (3) Preparation of coating solution for forming polyvinyl alcohol-based resin layer

將聚乙烯醇粉末(可樂麗股份有限公司製造之商品名「PVA124」、平均聚合度2400、平均皂化度98.0~99.0莫耳%)溶解於95℃之熱水，製備濃度8重量%之聚乙烯醇水溶液，將其製成聚乙烯醇系樹脂層形成用塗佈液。 Polyvinyl alcohol powder (trade name "PVA124" manufactured by Kuraray Co., Ltd., average degree of polymerization 2400, average degree of saponification 98.0-99.0 mol%) was dissolved in hot water at 95°C to prepare polyethylene with a concentration of 8% by weight The aqueous alcohol solution is used as a coating liquid for forming a polyvinyl alcohol-based resin layer.

(4)聚乙烯醇系樹脂層之形成 (4) Formation of polyvinyl alcohol-based resin layer

一面連續地搬送上述(1)中製作之基材膜，一面對其一個面實施電暈處理，繼而，使用小徑凹版塗佈機對經電暈處理之面連續地塗佈上述(2)中製備之底塗層形成用塗佈液，以60℃進行3分鐘乾燥，藉此形成厚度0.2μm之底塗層。繼而，一面搬送膜，一面使用卡馬塗佈機於底塗層上連續地塗佈上述(3)中製備之聚乙烯醇系樹脂層形成用塗佈液，以90℃進行4分鐘乾燥，藉此於底塗層上形成厚度9.5μm之聚乙烯醇系樹脂層(以下稱為「第一PVA層」)。 The substrate film produced in the above (1) was continuously transported on one side, corona treatment was carried out on one side thereof, and then the corona-treated surface was continuously coated with the above (2) using a small-diameter gravure coater The coating liquid for forming an undercoat layer prepared in the above was dried at 60° C. for 3 minutes, thereby forming an undercoat layer with a thickness of 0.2 μm. Then, while transporting the film, the coating solution for forming the polyvinyl alcohol-based resin layer prepared in (3) above was continuously coated on the undercoat layer using a kama coater, and dried at 90° C. for 4 minutes. This formed a 9.5 μm thick polyvinyl alcohol-based resin layer (hereinafter referred to as “first PVA layer”) on the undercoat layer.

繼而，於基材膜之與形成有第一PVA層之面為相反側之面上，以與上述相同之方式形成厚度0.2μm之底塗層，於底塗層上塗佈聚乙烯醇系樹脂層形成用塗佈液，以90℃進行4分鐘乾燥，藉此於底塗層上形成厚度9.4μm之聚乙烯醇系樹脂層(以下稱為「第二PVA層」)，獲得於雙面具有PVA層之積層膜。 Then, on the surface of the base film opposite to the surface on which the first PVA layer is formed, an undercoat layer with a thickness of 0.2 μm is formed in the same manner as above, and a polyvinyl alcohol-based resin is coated on the undercoat layer The coating solution for layer formation was dried at 90° C. for 4 minutes, thereby forming a polyvinyl alcohol-based resin layer (hereinafter referred to as “second PVA layer”) with a thickness of 9.4 μm on the undercoat layer. Laminated film of PVA layer.

(5)延伸膜之製作 (5) Production of stretch film

一面連續地搬送上述(4)中製作之積層膜，一面藉由夾輥間之延伸方法，於延伸溫度160℃下以5.3倍之倍率於縱方向(膜搬送方向)上進行單軸延伸，獲得延伸膜。關於延伸膜，第一PVA層之厚度成為5.0μm，第二PVA層之厚度成為4.9μm。 While continuously transporting the laminated film produced in (4) above, on the other hand, by the stretching method between the nip rolls, uniaxial stretching in the longitudinal direction (film transport direction) at a stretching temperature of 160° C. at a magnification of 5.3 times was performed to obtain Stretch film. Regarding the stretched film, the thickness of the first PVA layer became 5.0 μm, and the thickness of the second PVA layer became 4.9 μm.

(6)包含偏光膜(偏光元件層)之偏光性積層膜之製作 (6) Production of polarizing laminate film including polarizing film (polarizing element layer)

將上述(5)中製作之延伸膜以滯留時間230秒浸漬於碘化鉀/水為7.5/100(重量比)之含有碘之30℃之染色浴中(染色步驟)。其次，將自染色浴抽出之膜以滯留時間240秒浸漬於碘化鉀/硼酸/水為10/9.5/100(重量比)之78℃之交聯浴中，繼而，以滯留時間77秒浸漬於碘化鉀/硼酸/水為4.5/5.0/100(重量比)之70℃之交聯浴中(交聯步驟)。 The stretched film prepared in (5) above was immersed in a dyeing bath containing potassium iodide/water of 7.5/100 (weight ratio) at 30°C containing iodine at a residence time of 230 seconds (dyeing step). Next, the film extracted from the dyeing bath was immersed in a cross-linking bath of 78° C. with potassium iodide/boric acid/water of 10/9.5/100 (weight ratio) at a residence time of 240 seconds, and then immersed in potassium iodide at a residence time of 77 seconds /Boric acid/water is 4.5/5.0/100 (weight ratio) in a crosslinking bath at 70°C (crosslinking step).

其次，將自交聯浴抽出之膜以滯留時間22秒浸漬於包含4℃之純水之清洗浴中後(清洗步驟)，繼而，藉由導入至可調節濕度之第1加熱爐中，以滯留時間276秒進行高溫高濕處理(高溫高濕處理步驟)，獲得包含由上述第二PVA層所形成之厚度5.3μm、寬度210mm之偏光膜(偏光元件層)之偏光性積層膜。將第1加熱爐內之溫度、絕對濕度分別設為80℃、117g/m³，高溫高濕處理時之膜張力設為1290N/m。即將進行第1加熱爐導入(高溫高濕處理)之前、剛進行第1加熱爐導入(高溫高濕處理)後之膜之水分率分別為18.2重量%、10.7重量%，水分率差ΔS為7.5重量%。 Next, after immersing the film drawn from the cross-linking bath in a clean bath containing pure water at 4°C for a residence time of 22 seconds (washing step), then, by introducing into the first heating furnace with adjustable humidity, A high-temperature and high-humidity treatment (high-temperature and high-humidity treatment step) was performed for a residence time of 276 seconds to obtain a polarizing laminate film including a polarizing film (polarizing element layer) having a thickness of 5.3 μm and a width of 210 mm formed from the second PVA layer. The temperature and absolute humidity in the first heating furnace were set at 80°C and 117 g/m ³ , respectively, and the film tension during the high-temperature and high-humidity treatment was set at 1290 N/m. The moisture content of the film immediately before the introduction of the first heating furnace (high temperature and high humidity treatment) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment) were 18.2% by weight and 10.7% by weight, respectively, and the water content difference ΔS was 7.5 weight%.

<比較例7> <Comparative Example 7>

將第1加熱爐內之溫度及絕對濕度、以及藉由第1加熱爐進行處理時之膜張力變更為如表3所示，除此以外，以與實施例10相同之方式製作包含厚度5.3μm、寬度210mm之偏光膜(偏光元件層)之偏光性積層膜。第1加熱爐內之溫度、絕對濕度分別為65℃、8g/m³，於第1加熱爐中不進行高溫高濕處理，而僅進行加熱(乾燥)處理。 The temperature and the absolute humidity in the first heating furnace, and the film tension when processed in the first heating furnace were changed to those shown in Table 3, except that the thickness was 5.3 μm in the same manner as in Example 10. , Polarizing laminated film of 210mm wide polarizing film (polarizing element layer). The temperature and absolute humidity in the first heating furnace were 65° C. and 8 g/m ³ , respectively, and the high-temperature and high-humidity treatment was not performed in the first heating furnace, but only the heating (drying) treatment.

將實施例10及比較例7之偏光性積層膜之製造條件、即將進行第1加熱爐導入(高溫高濕處理)之前及剛進行第1加熱爐導入(高溫高濕處理)後之偏光膜之水分率、以及作為該等之差之水分率差ΔS彙總於表3。又，關於上述項目(除去配向度)，測定實施例10及比較例7之偏光膜之特性。將結果示於表3。再者，於使用附有積分球之分光光度計[日本分光股份有限公司製造之「V7100」]之Ty及Py之測定中，將自所獲得之偏光性積層膜剝離去除由第一PVA層形成之偏光膜之積層膜用作測定樣品。此時，自偏光膜(由第二PVA層形成之偏光膜)側入射光進行測定。又，MD收縮力係自所獲得之偏光性積層膜僅取出由第二PVA層形成之偏光膜，將其作為測定樣品。 The manufacturing conditions of the polarizing laminate film of Example 10 and Comparative Example 7 immediately before the introduction of the first heating furnace (high temperature and high humidity treatment) and immediately after the introduction of the first heating furnace (high temperature and high humidity treatment) Table 3 summarizes the water content and the water content difference ΔS which is the difference. In addition, regarding the above items (excluding the degree of alignment), the characteristics of the polarizing films of Example 10 and Comparative Example 7 were measured. The results are shown in Table 3. Furthermore, in the measurement of Ty and Py using a spectrophotometer ["V7100" manufactured by Japan Spectroscopy Co., Ltd.] with an integrating sphere, the polarizing laminate film obtained was peeled off and formed from the first PVA layer. The laminated film of the polarizing film is used as a measurement sample. At this time, light incident from the side of the polarizing film (the polarizing film formed by the second PVA layer) was measured. In addition, the MD shrinkage force is to take out only the polarizing film formed of the second PVA layer from the obtained polarizing laminate film, and use it as a measurement sample.

Claims (5)

一種偏光膜之製造方法，其包含：染色步驟，其利用二色性色素將聚乙烯醇系樹脂膜染色；交聯步驟，其利用交聯劑處理染色步驟後之膜；及高溫高濕處理步驟，其將作為交聯步驟後之膜且處於濕潤狀態之膜置於溫度40~100℃、絕對濕度40g/m³以上之環境下；該製造方法係藉由上述高溫高濕處理步驟降低膜之水分率，且上述高溫高濕處理步驟前後之膜之水分率差未達15重量%。 A method for manufacturing polarizing film, comprising: a dyeing step, which uses a dichroic pigment to dye the polyvinyl alcohol-based resin film; a crosslinking step, which uses a crosslinking agent to treat the film after the dyeing step; and a high temperature and high humidity treatment step , Which places the film in the wet state as the film after the cross-linking step in an environment with a temperature of 40 to 100° C. and an absolute humidity of 40 g/m ³ or more; the manufacturing method reduces the film by the above high-temperature and high-humidity treatment steps Moisture content, and the difference between the moisture content of the film before and after the high temperature and high humidity treatment step is less than 15% by weight. 如請求項1之製造方法，其進而包含使用含有水之清洗液清洗上述交聯步驟後之膜之清洗步驟，且上述高溫高濕處理步驟係對作為上述清洗步驟後之膜且處於濕潤狀態之膜實施。 The manufacturing method according to claim 1, which further includes a cleaning step of cleaning the film after the cross-linking step with a cleaning solution containing water, and the high-temperature and high-humidity treatment step is for the film after the cleaning step and in a wet state Membrane implementation. 如請求項1或2之製造方法，其中上述高溫高濕處理步驟之處理時間為5秒~60分鐘。 The manufacturing method according to claim 1 or 2, wherein the processing time of the high temperature and high humidity processing step is 5 seconds to 60 minutes. 一種偏光膜，其係使二色性色素吸附配向於聚乙烯醇系樹脂膜而成者，且基於由廣角X射線繞射測定所獲得之方位角分佈曲線，依照下述式：配向度(%)=(360-W)/360[式中，W為於將上述方位角分佈曲線之峰總體之積分值設為100%時，對所有峰求出積分值成為50%之峰全寬時之該等之和]求出之配向度於上述偏光膜之厚度為20μm以上時為71%以下，於上述偏光膜之厚度為10μm以上且未達20μm時為74.0%以下。 A polarizing film made by aligning a dichroic pigment to a polyvinyl alcohol resin film, and based on the azimuth distribution curve obtained by wide-angle X-ray diffraction measurement, according to the following formula: Alignment degree (% )=(360-W)/360[Where, W is when the integrated value of the total peaks of the above azimuth distribution curve is set to 100%, and the integrated value of all peaks is calculated as 50% of the full width of the peak The sum of these] is calculated to be 71% or less when the thickness of the polarizing film is 20 μm or more, and 74.0% or less when the thickness of the polarizing film is 10 μm or more and less than 20 μm. 一種偏光板，其包含如請求項4之偏光膜、及積層於其至少一面上之保護膜。 A polarizing plate comprising the polarizing film according to claim 4, and a protective film laminated on at least one side thereof.

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