JPH07104126A - Polarizing film manufacturing method - Google Patents
Polarizing film manufacturing methodInfo
- Publication number
- JPH07104126A JPH07104126A JP5249344A JP24934493A JPH07104126A JP H07104126 A JPH07104126 A JP H07104126A JP 5249344 A JP5249344 A JP 5249344A JP 24934493 A JP24934493 A JP 24934493A JP H07104126 A JPH07104126 A JP H07104126A
- Authority
- JP
- Japan
- Prior art keywords
- film
- polarizing film
- solvent
- iodide
- polyvinyl alcohol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Polarising Elements (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は耐湿熱性に優れた高性能
の偏光フィルムの製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-performance polarizing film having excellent wet heat resistance.
【０００２】[0002]
【従来の技術】液晶表示装置はワードプロセッサー、パ
ーソナルコンピューター、カラー液晶テレビ等に多用さ
れている。近年、液晶表示装置は車載用や野外用として
高温多湿の条件下で使用されることが多くなって来てい
る。液晶表示装置の高温多湿雰囲気下における信頼性を
向上させるために、耐湿熱性の高い偏光フィルムが強く
要望されている。また最近では液晶表示素子の白黒表示
あるいはカラー表示が一般的になりつつある。このよう
な表示に対応するために、耐湿熱性に優れると同時に透
過率および偏光度の高い偏光フィルムが要望されてい
る。従来、偏光フィルムは、延伸配向した偏光膜基材フ
ィルムにヨウ素または二色性染料を吸着させて作製され
ている。偏光フィルムには両面に光学的に透明で異方性
の無いフィルムを保護膜として使用するのが一般的であ
る。保護膜としてはトリアセテートフィルム（トリアセ
チルセルロースフィルム）が用いられている。偏光子の
基材フィルムとしてはポリビニルアルコール系重合体が
一般的に使用されている。ヨウ素系偏光フィルムの一般
的な作り方は延伸したポリビニルアルコール系フィルム
にヨウ素を吸着させ、ホウ酸を含む固定水溶液で処理し
た後、偏光子の両面にトリアセテートフィルムからなる
保護フィルムを張り合せるという手法が一般的である。
染料系偏光フィルムの一般的な製法としては一軸延伸フ
ィルムに二色性染料を吸着させる方法が使用されてい
る。この場合に使用される高分子フィルムとしてはポリ
ビニルアルコール系フィルムが好適に用いられている。
特にポリビニルアルコール系フィルムにヨウ素を吸着さ
せた偏光フィルムが透過率および偏光度の点で最も優れ
ており、偏光フィルムとして最も一般的に使用されてい
る。2. Description of the Related Art Liquid crystal display devices are widely used in word processors, personal computers, color liquid crystal televisions and the like. 2. Description of the Related Art In recent years, liquid crystal display devices have been increasingly used under high temperature and high humidity conditions for in-vehicle use and outdoor use. In order to improve the reliability of a liquid crystal display device in a high temperature and high humidity atmosphere, a polarizing film having high resistance to moist heat is strongly desired. In recent years, monochrome display or color display of liquid crystal display elements has become common. In order to cope with such a display, a polarizing film having excellent resistance to moisture and heat and high transmittance and polarization degree is demanded. Conventionally, a polarizing film is produced by adsorbing iodine or a dichroic dye on a stretched and oriented polarizing film substrate film. For the polarizing film, it is general to use a film which is optically transparent on both sides and has no anisotropy as a protective film. A triacetate film (triacetyl cellulose film) is used as the protective film. A polyvinyl alcohol-based polymer is generally used as a base film of a polarizer. A common method for making iodine-based polarizing film is to adsorb iodine on a stretched polyvinyl alcohol-based film, treat it with a fixed aqueous solution containing boric acid, and then attach a protective film consisting of a triacetate film to both sides of the polarizer. It is common.
As a general method for producing a dye-based polarizing film, a method of adsorbing a dichroic dye on a uniaxially stretched film is used. A polyvinyl alcohol-based film is preferably used as the polymer film used in this case.
In particular, a polarizing film prepared by adsorbing iodine on a polyvinyl alcohol film is most excellent in terms of transmittance and degree of polarization, and is most commonly used as a polarizing film.
【０００３】[0003]
【発明が解決しようとする課題】ポリビニルアルコール
系偏光フィルムは耐湿熱性が悪いという問題点がある。
例えば、８０℃、９０％相対湿度（ＲＨ）の雰囲気下に
おける耐湿熱性をヨウ素を吸着させた偏光フィルムで試
験した場合（偏光子の両面をトリアセテートフィルムで
保護したもの）、偏光フィルムをクロスニコルの状態に
設置し（偏光度９９．９％）上記の条件で観察を行なっ
たところ、１００時間で偏光度が７５％まで低下し、さ
らに２５０時間で偏光度が０．８％まで低下した。上記
の結果において示されるように従来の偏光フィルムの耐
湿熱性は極めて乏しかった。偏光フィルムの耐湿熱性を
向上させるために、種々の方法が提案されている。ポリ
エステルやポリメチルメタクリレート系樹脂等の水分透
過率の低い保護層をトリアセテートフィルムの上に設置
する方法があるが、光線透過率が低下したり、干渉縞が
発生する等の実用上の問題点があった。本発明はこのよ
うな問題点を解決し、偏光特性および耐湿熱性に優れた
偏光フィルムを提供することを目的とする。The polyvinyl alcohol-based polarizing film has a problem that it has poor resistance to moisture and heat.
For example, when the resistance to moist heat in an atmosphere of 80 ° C. and 90% relative humidity (RH) was tested on a polarizing film having iodine adsorbed (both sides of the polarizer were protected by triacetate film), the polarizing film was crossed When it was placed in the state (polarization degree 99.9%) and observed under the above conditions, the polarization degree decreased to 75% in 100 hours, and further decreased to 0.8% in 250 hours. As shown in the above results, the conventional polarizing film has extremely poor resistance to moisture and heat. Various methods have been proposed to improve the wet heat resistance of the polarizing film. There is a method of installing a protective layer with low water permeability such as polyester or polymethylmethacrylate resin on the triacetate film, but there are practical problems such as reduction of light transmittance and occurrence of interference fringes. there were. An object of the present invention is to solve such problems and provide a polarizing film having excellent polarization characteristics and wet heat resistance.
【０００４】[0004]
【課題を解決するための手段】本発明者は上記の問題を
解決するために鋭意検討した結果、ポリビニルアルコー
ル系樹脂よりなるフィルムをアルカリ金属のヨウ化物を
含有させた酸化剤を含む酸化浴中で酸化処理することを
特徴とする偏光度９５％以上のヨウ素系偏光フィルムの
製造方法を見出し本発明に到達した。Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventor has found that a film made of a polyvinyl alcohol-based resin is used in an oxidizing bath containing an oxidizing agent containing an alkali metal iodide. The present invention has been accomplished by finding a method for producing an iodine-based polarizing film having a polarization degree of 95% or more, which is characterized by performing an oxidation treatment with.
【０００５】以下において、本発明の偏光フィルムの製
造方法をより具体的に示す。ポリビニルアルコール系樹
脂の平均重合度は１５００〜４０００が好ましく、ケン
化度は８５モル％以上が好ましく、９５モル％以上がよ
り好ましい。次にポリビニルアルコール系樹脂とアルカ
リ金属のヨウ化物をともに同じ溶媒に溶解させる。この
場合に使用される溶媒としては、水、有機溶媒あるいは
水と有機溶媒との混合溶媒を用いるのが良い。有機溶媒
としてはジメチルスルホキシド、グリセリン、エチレン
グリコール、プロピレングリコール等を使用することが
できる。ポリビニルアルコールの濃度は溶媒に対して１
〜５０重量％、好ましくは３〜３０重量％とするのが良
い。溶解させるアルカリ金属の濃度はポリビニルアルコ
ールに対して０．５〜２０重量％、好ましくは１〜１５
重量％とするのが良い。本発明におけるポリビニルアル
コール系樹脂としては例えばポリビニルアルコール、ポ
リビニルホルマール、ポリビニルアセタール、ポリビニ
ルブチラール、エチレン−酢酸ビニル共重合体ケン化物
等である。特に好ましく用いられるのはポリビニルアル
コールである。The method for producing the polarizing film of the present invention will be described in more detail below. The average degree of polymerization of the polyvinyl alcohol resin is preferably 1500 to 4000, and the degree of saponification is preferably 85 mol% or more, more preferably 95 mol% or more. Next, the polyvinyl alcohol resin and the alkali metal iodide are both dissolved in the same solvent. The solvent used in this case is preferably water, an organic solvent, or a mixed solvent of water and an organic solvent. As the organic solvent, dimethyl sulfoxide, glycerin, ethylene glycol, propylene glycol or the like can be used. The concentration of polyvinyl alcohol is 1 with respect to the solvent
˜50% by weight, preferably 3 to 30% by weight. The concentration of the alkali metal to be dissolved is 0.5 to 20% by weight with respect to polyvinyl alcohol, preferably 1 to 15
It is good to set it as a weight%. Examples of the polyvinyl alcohol resin in the present invention include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, and saponified ethylene-vinyl acetate copolymer. Polyvinyl alcohol is particularly preferably used.
【０００６】本発明において用いられるアルカリ金属の
ヨウ化物としてはヨウ化カリウム、ヨウ化ナトリウム、
ヨウ化リチウム等が用いられる。本発明においてはポリ
ビニルアルコール系樹脂とアルカリ金属のヨウ化物を同
じ溶媒に溶解させた後にキャスト製膜を行なうことによ
りアルカリ金属のヨウ化物を溶解させたポリビニルアル
コールのフィルムを得る。得られたフィルムを過酸化水
素等の酸化剤を含む酸化浴中に浸漬することにより、酸
化処理されて、Ｉ3 -、Ｉ5 -等のヨウ素をポリビニルアル
コールのフィルム中に生成させる。本発明においては酸
化条件の選定が最も重要である。すなわち酸化浴中に硫
酸あるいは塩酸等の強酸を添加し、強酸性とした場合に
は酸化速度が制御できない程度に早くなる結果、得られ
るヨウ素で染色された状態のポリビニルアルコールフィ
ルムの光線透過率が著しく低下し、偏光フィルムとして
利用可能なフィルムが得られない傾向にある。本発明に
おける酸化浴中の水素イオン濃度指数（ＰＨ）は３〜９
に制御することが偏光フィルムの偏光度が向上するので
好ましい。ＰＨが３より低いと酸化速度の制御が困難と
なり性能の良い偏光フィルムは得られないことが多い。
ＰＨが９より高い場合には酸化速度が著しく遅くなり偏
光フィルムの偏光性能が低下する傾向がある。Alkali metal iodides used in the present invention include potassium iodide, sodium iodide,
Lithium iodide or the like is used. In the present invention, a polyvinyl alcohol film in which the alkali metal iodide is dissolved is obtained by dissolving the polyvinyl alcohol resin and the alkali metal iodide in the same solvent and then performing cast film formation. The obtained film is subjected to an oxidation treatment by immersing it in an oxidizing bath containing an oxidizing agent such as hydrogen peroxide to generate iodine such as I 3 − and I 5 − in the polyvinyl alcohol film. In the present invention, selection of oxidation conditions is the most important. That is, when a strong acid such as sulfuric acid or hydrochloric acid is added to the oxidation bath to make it strongly acidic, the oxidation rate becomes uncontrollably fast, resulting in a light transmittance of the obtained polyvinyl alcohol film dyed with iodine. It is remarkably reduced, and there is a tendency that a film usable as a polarizing film cannot be obtained. The hydrogen ion concentration index (PH) in the oxidation bath in the present invention is 3 to 9
It is preferable to control the ratio so that the polarization degree of the polarizing film is improved. When the pH is lower than 3, it is difficult to control the oxidation rate and a polarizing film with good performance cannot be obtained in many cases.
If the pH is higher than 9, the oxidation rate will be remarkably slowed and the polarizing performance of the polarizing film tends to be deteriorated.
【０００７】また酸化浴の温度は２５℃以下、好ましく
は１５℃以下であることが好ましい。酸化浴の温度を下
げることによって、偏光フィルムの単体透過率および偏
光度を上げることができるので良い。温度を下げること
により偏光フィルムの性能が上がる理由は正確には解ら
ないが、より温和な条件で反応させる事により偏光フィ
ルムに適するヨウ素分子を生成させることができるので
良いと思われる。酸化剤としては過酸化水素のように温
和な酸化剤が最適である。The temperature of the oxidizing bath is preferably 25 ° C. or lower, more preferably 15 ° C. or lower. By lowering the temperature of the oxidation bath, it is possible to increase the single transmittance and the degree of polarization of the polarizing film. Although the reason why the performance of the polarizing film is improved by lowering the temperature is not exactly understood, it is considered that it is possible to generate iodine molecules suitable for the polarizing film by reacting under a milder condition. A mild oxidizing agent such as hydrogen peroxide is most suitable as the oxidizing agent.
【０００８】このようにして得られたヨウ素で染色され
たポリビニルアルコールの原反フィルムを水中あるいは
空気中において、２〜６倍、好ましくは３〜５倍に延伸
する。延伸を行なった後に緊張状態を保持したまま架橋
剤を含む溶液中で処理を行なうのが良い。この場合に使
用する架橋剤としては、ほう酸、ほう砂、チタン化合
物、ジルコニウム化合物等が用いられる。架橋剤により
架橋処理温度は２０〜１１０℃の温度で行なうのが良
い。得られた偏光フィルムの片面あるいは両面に保護層
を形成して偏光フィルムを得る。保護フィルムとしては
トリアセチルセルロースフィルム等の透明フィルムを用
いることができる。酸化処理時間については、温度が１
５〜２５℃の場合には、３０秒間以下が好ましく、温度
が０〜１０℃の場合には、１分間以上が好ましく、２分
間以上がより好ましい。The thus obtained iodine-dyed raw film of polyvinyl alcohol is stretched in water or in air to 2 to 6 times, preferably 3 to 5 times. After stretching, the treatment is preferably carried out in a solution containing a cross-linking agent while maintaining the tension. As the cross-linking agent used in this case, boric acid, borax, titanium compound, zirconium compound or the like is used. The crosslinking treatment temperature is preferably 20 to 110 ° C. depending on the crosslinking agent. A protective layer is formed on one side or both sides of the obtained polarizing film to obtain a polarizing film. A transparent film such as a triacetyl cellulose film can be used as the protective film. Regarding the oxidation treatment time, the temperature is 1
In the case of 5 to 25 ° C, 30 seconds or less is preferable, and in the case of temperature of 0 to 10 ° C, 1 minute or more is preferable, and 2 minutes or more is more preferable.
【０００９】[0009]
【実施例】以下実施例において本発明をさらに詳細に説
明する。The present invention will be described in more detail in the following examples.
【００１０】実施例１ 重合度１７００、ケン化度９９．７モル％のポリビニル
アルコールを水に対して５重量％の割合で溶解させた。
溶解は８０℃の条件で行なった。温度を室温まで冷却し
た後、ポリビニルアルコールに対して１０重量％の割合
でヨウ化リチウムを添加し溶解させた。この溶液をポリ
エチレンテレフタレートのフィルムの上にキャストし、
厚さが７０μｍのヨウ化リチウムを含むポリビニルアル
コールのフィルムを得た。このフィルムを１２０℃で１
０分間熱処理を行なった。このフィルムを０℃の温度に
おいて、１０重量％の過酸化水素水溶液（ＰＨ６．４）
中に３分間浸漬して酸化処理をした。この後、０℃の水
で、このフィルムを洗浄した。続いて５０℃、５重量％
のほう酸水溶液中に３０秒間浸漬した後、水中において
４倍延伸を行った。このフィルムを緊張状態に保持した
まま、ほう酸１０重量％を含む５０℃の水溶液に４分間
浸漬した。この後４０℃で５分間乾燥することにより、
偏光フィルムを得た。この偏光フィルムの両面に厚さ８
０μｍのトリアセチルセルロースフィルムをポリビニル
アルコール系接着剤を用いて接着することにより、偏光
フィルムを得た。この偏光フィルムの透過率と偏光度を
測定した。単体透過率は４０％、偏光度は９９．９％で
あった（クロスニコルの状態に設置した場合垂直方向に
おける透過率は０．０５％以下であった。透過率は日本
電子工業界規格（ＬＤ−２０１）に準じて測定した（４
００ｎｍ〜７００ｎｍの波長域において１０ｎｍ毎に測
定した分光透過率から算出した）。偏光度は下記の式よ
り求めた値である。 偏光度（％）＝（Ｈ1−Ｈ2）／（Ｈ1＋Ｈ2）×１００ Ｈ1：平行透過率（２枚の偏光フィルムの配向方向が同
一方向になるようにした場合の透過率） Ｈ2：垂直透過率（２枚の偏光フィルムの配向方向が直
行した場合の透過率） この偏光フィルム（両面にトリアセテートフィルムを接
着した状態において）の耐湿熱性を８０℃、９０％ＲＨ
の雰囲気において測定した。その結果を図１に示す。従
来の偏光フィルムと比較し本発明の偏光フィルムは耐湿
熱性が大幅に向上していた。Example 1 Polyvinyl alcohol having a degree of polymerization of 1700 and a degree of saponification of 99.7 mol% was dissolved in water at a ratio of 5% by weight.
The dissolution was performed at 80 ° C. After cooling to room temperature, lithium iodide was added and dissolved at a ratio of 10% by weight with respect to polyvinyl alcohol. Cast this solution on a film of polyethylene terephthalate,
A film of polyvinyl alcohol containing lithium iodide having a thickness of 70 μm was obtained. This film at 120 ℃ 1
Heat treatment was performed for 0 minutes. This film was treated with a 10% by weight aqueous hydrogen peroxide solution (PH6.4) at a temperature of 0 ° C.
It was immersed in the inside for 3 minutes for oxidation treatment. After this, the film was washed with water at 0 ° C. Then 50 ° C, 5% by weight
After being immersed in the aqueous boric acid solution for 30 seconds, it was stretched 4 times in water. While keeping this film in a tensioned state, it was dipped in an aqueous solution containing 10% by weight of boric acid at 50 ° C. for 4 minutes. After that, by drying at 40 ° C for 5 minutes,
A polarizing film was obtained. Thickness 8 on both sides of this polarizing film
A 0 μm triacetyl cellulose film was adhered with a polyvinyl alcohol-based adhesive to obtain a polarizing film. The transmittance and the degree of polarization of this polarizing film were measured. The single substance transmittance was 40%, and the polarization degree was 99.9% (when installed in the crossed Nicols state, the vertical transmittance was 0.05% or less. It measured according to LD-201) (4
It was calculated from the spectral transmittance measured every 10 nm in the wavelength range of 00 nm to 700 nm). The degree of polarization is a value obtained from the following formula. Polarization degree (%) = (H 1 −H 2 ) / (H 1 + H 2 ) × 100 H 1 : Parallel transmittance (transmittance when the two polarizing films are oriented in the same direction) H 2: (transmittance in the case where the alignment direction of the two polarizing films were orthogonal) perpendicular transmittance the 80 ° C. wet heat resistance of the polarizing film (in a state where the adhesive triacetate film on both sides), 90% RH
Was measured in the atmosphere. The result is shown in FIG. Compared with the conventional polarizing film, the polarizing film of the present invention had significantly improved wet heat resistance.
【００１１】比較例１ 重合度１７００、ケン化度９９．７モル％のポリビニル
アルコール１０部を水９０部に溶解し、ポリビニルアル
コール濃度が１０重量％の溶液を得た。この溶液をポリ
エチレンテレフタレートフィルムに流延後乾燥し、膜厚
が７０μｍのポリビニルアルコールの原反フィルムを得
た。この原反フィルムを水中に浸漬し４倍延伸を行なっ
た。さらにこのフィルムを緊張状態に保持したまま、ヨ
ウ素０．５重量％、ヨウ化カリウム５重量％からなる水
溶液に浸漬しヨウ素を吸着させた。さらに、ほう酸１０
重量％、ヨウ化カリウム１０重量％からなる５０℃の水
溶液で５分間架橋処理を行なった。この架橋処理は緊張
状態で行なった。この後４０℃で５分間乾燥した。この
偏光フィルムの両面に実施例１と同様にしてポリビニル
アルコール系接着剤を用いてトリアセチルセルロースフ
ィルム（富士写真フィルム製、フジタック）を接着し
た。このようにして偏光フィルムを得た。この偏光フィ
ルムの単体透過率は４１％、偏光度は９９．９％であっ
た。この偏光フィルムの耐湿熱性を８０℃、９０％ＲＨ
の雰囲気において測定した。その結果を図１に示す。Comparative Example 1 10 parts of polyvinyl alcohol having a degree of polymerization of 1700 and a saponification degree of 99.7 mol% was dissolved in 90 parts of water to obtain a solution having a polyvinyl alcohol concentration of 10% by weight. This solution was cast on a polyethylene terephthalate film and then dried to obtain a polyvinyl alcohol original film having a thickness of 70 μm. This raw film was immersed in water and stretched 4 times. Further, while keeping this film in a tension state, it was immersed in an aqueous solution containing 0.5% by weight of iodine and 5% by weight of potassium iodide to adsorb iodine. Furthermore, boric acid 10
The crosslinking treatment was performed for 5 minutes with an aqueous solution of 50% by weight and potassium iodide at 10% by weight at 50 ° C. This cross-linking treatment was carried out under tension. After that, it was dried at 40 ° C. for 5 minutes. A triacetyl cellulose film (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) was adhered to both surfaces of this polarizing film using a polyvinyl alcohol-based adhesive in the same manner as in Example 1. Thus, a polarizing film was obtained. The single transmittance of this polarizing film was 41%, and the polarization degree was 99.9%. Wet heat resistance of this polarizing film is 80 ℃, 90% RH
Was measured in the atmosphere. The result is shown in FIG.
【００１２】実施例２ 重合度１７００、ケン化度９９．７モル％のポリビニル
アルコールを水に対して５重量％の割合で溶解させた。
溶解は８０℃の条件で行なった。温度を室温まで冷却し
た後にポリビニルアルコールに対して１０重量％の割合
でヨウ化カリウムを添加し、溶解させた。この溶液をポ
リエチレンテレフタレートのフィルム上にキャストし、
厚さが７０μｍのヨウ化カリウムを含むポリビニルアル
コールのフィルムを得た。このフィルムを１２０℃で１
０分間熱処理を行なった。このフィルムを０℃の温度に
おいて、１０重量％の過酸化水素水溶液（ＰＨ６．０）
中に一定時間（図２に示す）浸漬して酸化処理した。こ
の後、０℃の水で、このフィルムを洗浄した。続いて５
０℃、５重量％のほう酸水溶液中に３０秒間浸漬した
後、水中において４倍延伸を行なった。この膜を緊張状
態に保持したまま、ほう酸１０重量％を含む５０℃の水
溶液に４分間浸漬した。この後４０℃で５分間乾燥する
ことにより、偏光フィルムを得た。この偏光フィルムの
両面に厚さ８０μｍのトリアセチルセルロースフィルム
をポリビニルアルコール系接着剤を用いて接着すること
によって偏光フィルムを得た。この偏光フィルムの偏光
度と酸化時間との関係を図２に示す。酸化時間を３０秒
以上にすることによって高い偏光度を有する偏光フィル
ムを得ることができた。Example 2 Polyvinyl alcohol having a polymerization degree of 1700 and a saponification degree of 99.7 mol% was dissolved in water at a ratio of 5% by weight.
The dissolution was performed at 80 ° C. After cooling to room temperature, potassium iodide was added at a ratio of 10% by weight to polyvinyl alcohol and dissolved. Cast this solution on a film of polyethylene terephthalate,
A film of polyvinyl alcohol containing potassium iodide having a thickness of 70 μm was obtained. This film at 120 ℃ 1
Heat treatment was performed for 0 minutes. This film was treated with a 10% by weight aqueous hydrogen peroxide solution (PH 6.0) at a temperature of 0 ° C.
It was immersed for a certain period of time (shown in FIG. 2) in it and subjected to an oxidation treatment. After this, the film was washed with water at 0 ° C. Then 5
After being immersed in a 5% by weight boric acid aqueous solution at 0 ° C. for 30 seconds, it was stretched 4 times in water. While keeping the membrane in a tensioned state, it was immersed in an aqueous solution containing 10% by weight of boric acid at 50 ° C. for 4 minutes. Then, a polarizing film was obtained by drying at 40 ° C. for 5 minutes. A 80 μm thick triacetyl cellulose film was adhered to both sides of this polarizing film using a polyvinyl alcohol-based adhesive to obtain a polarizing film. The relationship between the degree of polarization and the oxidation time of this polarizing film is shown in FIG. By setting the oxidation time to 30 seconds or more, a polarizing film having a high degree of polarization could be obtained.
【００１３】実施例３ 酸化する温度を２５℃としたこと以外は、実施例２と同
様にして実験を行なった。その結果を図２に示す。酸化
温度を２５℃にした場合には酸化時間が増大するにつれ
て偏光度が大きく低下した。偏光度が大きく低下した理
由は偏光フィルムが大きく着色することに起因してい
た。酸化温度を上げた場合には良好な偏光フィルムを得
るために、酸化時間を短時間に制御する必要があった。Example 3 An experiment was conducted in the same manner as in Example 2 except that the oxidizing temperature was 25 ° C. The result is shown in FIG. When the oxidation temperature was set to 25 ° C., the degree of polarization greatly decreased as the oxidation time increased. The reason why the degree of polarization was greatly decreased was that the polarizing film was greatly colored. When the oxidation temperature was raised, it was necessary to control the oxidation time to a short time in order to obtain a good polarizing film.
【００１４】[0014]
【発明の効果】本発明によると、耐湿熱性に優れた偏光
フィルムが提供される。According to the present invention, a polarizing film having excellent wet heat resistance is provided.
【図１】実施例１（□）および比較例１（○）ついての
耐湿熱性を示す。FIG. 1 shows the resistance to moist heat of Example 1 (□) and Comparative Example 1 (◯).
【図２】実施例２（○）および実施例３（△）について
の酸化時間と偏光度の関係を示す。FIG. 2 shows the relationship between the oxidation time and the polarization degree for Example 2 (◯) and Example 3 (Δ).
Claims (1)
ィルムをアルカリ金属のヨウ化物を含有させた酸化剤を
含む酸化浴中で酸化処理することを特徴とする偏光度９
５％以上のヨウ素系偏光フィルムの製造方法。1. A polarization degree of 9, wherein a film made of a polyvinyl alcohol resin is subjected to an oxidation treatment in an oxidizing bath containing an oxidizing agent containing an alkali metal iodide.
5% or more of the manufacturing method of an iodine type polarizing film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24934493A JP3410523B2 (en) | 1993-10-05 | 1993-10-05 | Manufacturing method of polarizing film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24934493A JP3410523B2 (en) | 1993-10-05 | 1993-10-05 | Manufacturing method of polarizing film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07104126A true JPH07104126A (en) | 1995-04-21 |
| JP3410523B2 JP3410523B2 (en) | 2003-05-26 |
Family
ID=17191633
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24934493A Expired - Fee Related JP3410523B2 (en) | 1993-10-05 | 1993-10-05 | Manufacturing method of polarizing film |
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| Country | Link |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005010576A1 (en) * | 2003-07-24 | 2005-02-03 | Nitto Denko Corporation | Method for producing poly(vinyl alcohol) based film dyed with iodine, polarizer, polarizing plate, optical film and image display device |
| JP2005054171A (en) * | 2003-07-24 | 2005-03-03 | Nitto Denko Corp | Method for producing iodine-stained polyvinyl alcohol film, method for producing polarizer, polarizer, polarizing plate, optical film, and image display device |
| US7289266B1 (en) | 2002-10-08 | 2007-10-30 | Nitto Denko Corporation | Polarizer, optical film, and image display |
| WO2013154139A1 (en) * | 2012-04-13 | 2013-10-17 | 日本化薬株式会社 | Polarizing element, and polarizer |
| KR20160129063A (en) * | 2014-03-14 | 2016-11-08 | 닛토덴코 가부시키가이샤 | Laminate, stretched laminate, method for manufacturing stretched laminate, method for manufacturing polarizing-film-containing optical-film laminate using same, and polarizing film |
| US9488756B2 (en) | 2011-05-26 | 2016-11-08 | Nitto Denko Corporation | Pressure-sensitive adhesive layer-attached polarizing film and image display |
| WO2018186243A1 (en) * | 2017-04-03 | 2018-10-11 | 日東電工株式会社 | Polarizer production method |
| WO2018186244A1 (en) * | 2017-04-03 | 2018-10-11 | 日東電工株式会社 | Polarizer and polarizing plate |
| KR20200010204A (en) | 2017-05-19 | 2020-01-30 | 닛뽄 가야쿠 가부시키가이샤 | Polarizing element, and polarizing plate and liquid crystal display device using the same |
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|---|---|---|---|---|
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| JP2005054171A (en) * | 2003-07-24 | 2005-03-03 | Nitto Denko Corp | Method for producing iodine-stained polyvinyl alcohol film, method for producing polarizer, polarizer, polarizing plate, optical film, and image display device |
| WO2005010576A1 (en) * | 2003-07-24 | 2005-02-03 | Nitto Denko Corporation | Method for producing poly(vinyl alcohol) based film dyed with iodine, polarizer, polarizing plate, optical film and image display device |
| US9488756B2 (en) | 2011-05-26 | 2016-11-08 | Nitto Denko Corporation | Pressure-sensitive adhesive layer-attached polarizing film and image display |
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| US9557450B2 (en) | 2011-05-26 | 2017-01-31 | Nitto Denko Corporation | Pressure-sensitive adhesive layer-attached polarizing film and image display |
| WO2013154139A1 (en) * | 2012-04-13 | 2013-10-17 | 日本化薬株式会社 | Polarizing element, and polarizer |
| JPWO2013154139A1 (en) * | 2012-04-13 | 2015-12-17 | 日本化薬株式会社 | Polarizing element and polarizing plate |
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| US10101514B2 (en) | 2014-03-14 | 2018-10-16 | Nitto Denko Corporation | Laminate, stretched laminate, manufacturing method of stretched laminate, manufacturing method of optical film laminate having polarizing film using the same, and polarizing film |
| WO2018186243A1 (en) * | 2017-04-03 | 2018-10-11 | 日東電工株式会社 | Polarizer production method |
| WO2018186244A1 (en) * | 2017-04-03 | 2018-10-11 | 日東電工株式会社 | Polarizer and polarizing plate |
| CN110462467A (en) * | 2017-04-03 | 2019-11-15 | 日东电工株式会社 | Manufacturing method of polarizer |
| JPWO2018186244A1 (en) * | 2017-04-03 | 2019-11-21 | 日東電工株式会社 | Polarizer and polarizing plate |
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| KR20190132995A (en) * | 2017-04-03 | 2019-11-29 | 닛토덴코 가부시키가이샤 | Manufacturing method of polarizer |
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