JP4323280B2 - Manufacturing method of polarizing film, manufacturing method of polarizing plate, and manufacturing method of optical laminate - Google Patents
Manufacturing method of polarizing film, manufacturing method of polarizing plate, and manufacturing method of optical laminate Download PDFInfo
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- JP4323280B2 JP4323280B2 JP2003348465A JP2003348465A JP4323280B2 JP 4323280 B2 JP4323280 B2 JP 4323280B2 JP 2003348465 A JP2003348465 A JP 2003348465A JP 2003348465 A JP2003348465 A JP 2003348465A JP 4323280 B2 JP4323280 B2 JP 4323280B2
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
- B29K2995/0034—Polarising
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Description
本発明は、色ムラの少ない偏光フィルムの製造方法、この偏光フィルムの少なくとも片面に保護フィルムを積層した偏光板の製造方法、さらに位相差フィルム、輝度向上フィルム、視野角改良フィルムおよび半透過反射フィルムのいずれかが単独または複数貼合されてなる光学積層体の製造方法に関する。 The present invention relates to a method for producing a polarizing film with little color unevenness, a method for producing a polarizing plate in which a protective film is laminated on at least one surface of the polarizing film, a retardation film, a brightness enhancement film, a viewing angle improvement film, and a transflective film. It is related with the manufacturing method of the optical laminated body in which any of these is individual or multiple bonded.
偏光フィルムとしては、従来から、ポリビニルアルコール系フィルムに二色性色素を吸着配向させたものが用いられている。すなわち、ヨウ素を二色性色素とするヨウ素系偏光フィルムや、二色性染料を二色性色素とする染料系偏光フィルムなどが知られている。これらの偏光フィルムは、通常、その少なくとも片面、好ましきは両面にポリビニルアルコール系樹脂の水溶液からなる接着剤を介してトリアセチルセルロース等の保護フィルムを貼合して、偏光板とされる。 Conventionally, a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol film has been used. That is, an iodine polarizing film using iodine as a dichroic dye, a dye polarizing film using a dichroic dye as a dichroic dye, and the like are known. These polarizing films are usually formed into a polarizing plate by bonding a protective film such as triacetyl cellulose on at least one side, preferably both sides, with an adhesive made of an aqueous solution of a polyvinyl alcohol resin.
偏光フィルムの製造方法として、例えば特許文献1には、ポリビニルアルコール系フィルムを水に浸漬して膨潤させた後、前記二色性色素で染色し、これを延伸し、ついでヨウ素をフィルムに定着させるためにポリビニルアルコール系フィルムをホウ酸処理(すなわち架橋による耐水化処理)し、水洗した後、乾燥する方法が記載されている。膨潤は、染色に先立ってフィルムを均一に膨潤させ、染色時間の短縮、染色ムラの改善などを目的として行われる。このとき、染色ムラなどの観点から、特許文献1では、膨潤処理浴にホウ酸を含有させている。そして、特許文献1では、染色後にホウ酸を含む浴液にフィルムを浸漬して延伸を行なっている。 As a method for producing a polarizing film, for example, in Patent Document 1, after a polyvinyl alcohol film is immersed in water and swollen, it is dyed with the dichroic dye, stretched, and then fixed with iodine to the film. For this purpose, a method is described in which a polyvinyl alcohol film is treated with boric acid (that is, water-resistant by crosslinking), washed with water, and then dried. Swelling is performed for the purpose of uniformly swelling the film prior to dyeing, shortening the dyeing time, and improving dyeing unevenness. At this time, from the viewpoint of uneven dyeing and the like, in Patent Document 1, boric acid is contained in the swelling treatment bath. And in patent document 1, it is extending | stretching by immersing a film in the bath liquid containing a boric acid after dyeing | staining.
また、特許文献2では、フィルムを十分に膨潤させるために、膨潤処理浴に塩化リチウム、塩化亜鉛などの塩化物を添加している。 Moreover, in patent document 2, in order to fully swell a film, chlorides, such as lithium chloride and zinc chloride, are added to the swelling treatment bath.
上記特許文献1および2では、フィルムから溶出した可塑剤(グリセリン等)の蓄積で膨潤処理浴に不具合があった時、膨潤処理浴の液を捨てる際にホウ酸や塩化物などの薬品も一緒に捨てることになるので、経済面、環境面で問題がある。また、特許文献1および2のように、膨潤処理浴にホウ酸や塩化物などの薬品を添加する方法は、染色ムラの改善に対して十分とは言えなかった。
In the above Patent Documents 1 and 2, when there is a problem with swelling treatment bath accumulation of the eluted plasticizer from the film (glycerin), also chemicals such as boric acid or chloride when discarding the liquid swelling bath Because they are thrown away together, there are problems in terms of economy and environment. Further, as in Patent Documents 1 and 2, a method of adding chemicals such as boric acid and chloride in the swelling bath was not sufficient relative to the improvement of uneven dyeing.
一方、特許文献3の実施例2には、ポリビニルアルコール系フィルムを水に浸漬して膨潤させた後、ホウ酸を含有する延伸浴中で延伸、ついで染色処理することが記載されている。しかし、特許文献3の延伸倍率は3倍以上と大きく、実施例2では5.5倍に延伸しているため、染色ムラの改善には十分でなかった。 On the other hand, Example 2 of Patent Document 3 describes that a polyvinyl alcohol film is immersed in water to swell, then stretched in a stretching bath containing boric acid, and then dyed. However, since the stretching ratio of Patent Document 3 is as large as 3 times or more and in Example 2 it is stretched by 5.5 times, it was not sufficient for improving the dyeing unevenness.
特許文献4には、染色ムラを少なくするために、ポリビニルアルコール系フィルムを水浴中に浸漬して膨潤させ、かつ延伸処理することが記載されている。しかし、膨潤と同時に延伸処理する特許文献4の方法でも、染色ムラの改善に十分でなかった。 Patent Document 4 describes that a polyvinyl alcohol film is immersed in a water bath to swell and stretched in order to reduce dyeing unevenness. However, even the method of Patent Document 4 in which the stretching process is performed simultaneously with the swelling is not sufficient for improving the uneven dyeing.
特許文献5には、水中に浸漬後、水中で一軸延伸し、そして染色することが記載されている。この方法で色ムラは改善されるものの、未だ十分なものでなかった。 Patent Document 5 describes that after being immersed in water, it is uniaxially stretched and dyed in water. Although this method improves color unevenness, it is still not sufficient.
本発明は、色ムラの少ない偏光フィルムの製造方法、偏光板の製造方法および光学積層体の製造方法を提供することを課題とする。 This invention makes it a subject to provide the manufacturing method of a polarizing film with little color nonuniformity, the manufacturing method of a polarizing plate, and the manufacturing method of an optical laminated body.
本発明者らは、上記の課題を解決すべく鋭意検討を重ねた結果、ポリビニルアルコール系フィルムを膨潤処理、染色処理およびホウ酸処理の順に処理して偏光フィルムを製造する工程において、膨潤処理と染色処理との間に、フィルム状態を均一化するために湿式延伸工程を設けて、所定濃度のホウ酸含有水溶液中で所定の延伸倍率で一軸延伸する場合には、色ムラの少ない偏光フィルムが得られるという新たな事実を見出し、本発明を完成するに至った。 As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention manufactured a polarizing film by treating a polyvinyl alcohol film in the order of swelling treatment, dyeing treatment and boric acid treatment. In order to make the film state uniform during the dyeing process, when a uniaxial stretching is performed at a predetermined stretching ratio in a predetermined concentration boric acid-containing aqueous solution, a polarizing film with less color unevenness is obtained. The present inventors have found a new fact that it can be obtained and have completed the present invention.
本発明にかかる偏光フィルムの製造方法は、ポリビニルアルコール系フィルムを、膨潤処理、染色処理、ホウ酸処理の順に浴中で連続的に処理し、かつこれらの処理工程のうち少なくとも一の工程で一軸延伸して偏光フィルムを得る偏光フィルムの製造方法であって、膨潤処理後で染色処理の前に少なくとも1工程の湿式延伸工程を設け、該延伸工程において前記フィルムを水100重量部に対し、ホウ酸0.01〜2.0重量部を含む水溶液中で1.1倍以上3倍未満の延伸倍率で一軸延伸することを特徴とする。 In the method for producing a polarizing film according to the present invention, a polyvinyl alcohol film is continuously treated in a bath in the order of swelling treatment, dyeing treatment, and boric acid treatment, and at least one of these treatment steps is uniaxial. A polarizing film manufacturing method for obtaining a polarizing film by stretching, wherein at least one wet stretching process is provided after the swelling process and before the dyeing process, and in the stretching process, the film is added to 100 parts by weight of water. It is characterized by uniaxially stretching in an aqueous solution containing 0.01 to 2.0 parts by weight of an acid at a draw ratio of 1.1 to 3 times.
前記湿式延伸工程で使用される浴液の温度は10℃〜40℃であるのが好ましい。 The temperature of the bath liquid used in the wet stretching process is preferably 10 ° C to 40 ° C.
また、本発明にかかる偏光板の製造方法は、前記偏光フィルムの少なくとも片面に保護フィルムを貼合することを特徴とする。この保護フィルムは、位相差フィルム、輝度向上フィルム、視野角改良フィルムおよび半透過反射フィルムのいずれかの機能を備えているのがよい。あるいは、少なくとも片面に保護フィルムを貼合した前記偏光板に、位相差板、輝度向上フィルム、視野角改良フィルムおよび半透過反射板から選ばれる少なくとも1種を貼合して、光学積層体を製造することができる。 Moreover, the manufacturing method of the polarizing plate concerning this invention bonds a protective film to the at least single side | surface of the said polarizing film, It is characterized by the above-mentioned. This protective film may have any of the functions of a retardation film, a brightness enhancement film, a viewing angle improvement film, and a transflective film. Or at least 1 sort (s) chosen from a phase difference plate, a brightness improvement film, a viewing angle improvement film, and a transflective board is pasted on the polarizing plate which pasted a protective film on at least one side, and manufactures an optical layered product. can do.
本発明によれば、ポリビニルアルコール系フィルムを、膨潤処理後で染色処理の前に、水100重量部に対し、ホウ酸0.01〜2.0重量部を含む水溶液中で1.1倍以上3倍未満の延伸倍率で一軸延伸することにより、染色処理に先立ってフィルムの状態が均一化されるため、ムラのない染色が可能となり、色ムラの少ない偏光フィルムが得られるという効果がある。 According to the present invention, the polyvinyl alcohol-based film is 1.1 times or more in an aqueous solution containing 0.01 to 2.0 parts by weight of boric acid with respect to 100 parts by weight of water after the swelling process and before the dyeing process. By uniaxially stretching at a draw ratio of less than 3 times, the state of the film is made uniform prior to the dyeing process, so that there is an effect that uniform dyeing is possible and a polarizing film with little color unevenness is obtained.
本発明におけるポリビニルアルコール系フィルムを形成するポリビニルアルコール系樹脂は、通常、ポリ酢酸ビニル系樹脂をケン化したものが例示される。ケン化度としては、85モル%以上、好ましくは90モル%以上、より好ましくは99モル%〜100モル%である。ポリ酢酸ビニル系樹脂としては、酢酸ビニルの単独重合体であるポリ酢酸ビニルのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体、例えば、エチレン−酢酸ビニル共重合体などが挙げられる。共重合可能な他の単量体としては、例えば不飽和カルボン酸類、オレフィン類、ビニルエーテル類、不飽和スルホン酸類などが挙げられる。ポリビニルアルコール系樹脂の重合度としては、1000〜10000、好ましくは1500〜5000程度である。 Examples of the polyvinyl alcohol-based resin that forms the polyvinyl alcohol-based film in the present invention include those obtained by saponifying a polyvinyl acetate-based resin. As a saponification degree, it is 85 mol% or more, Preferably it is 90 mol% or more, More preferably, it is 99 mol%-100 mol%. Polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith, such as ethylene-vinyl acetate copolymer. Examples include coalescence. Examples of other copolymerizable monomers include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The degree of polymerization of the polyvinyl alcohol-based resin is about 1000 to 10,000, preferably about 1500 to 5,000.
これらのポリビニルアルコール系樹脂は変性されていてもよく、例えば、アルデヒド類で変性された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なども使用しうる。通常、偏光フィルム製造の開始材料としては、厚さが20μm〜100μm、好ましくは30μm〜80μmのポリビニルアルコール系樹脂フィルムの未延伸フィルムを用いる。工業的には、フィルムの幅は1500mm〜4000mmが実用的である。
この未延伸フィルムを、膨潤処理、延伸処理、染色処理、ホウ酸処理、水洗処理し、最後に乾燥して得られるポリビニルアルコール系偏光フィルムの厚みは、例えば約5〜50μm程度である。
These polyvinyl alcohol resins may be modified. For example, polyvinyl formal modified with aldehydes, polyvinyl acetal, polyvinyl butyral, and the like may be used. Usually, as a starting material for producing a polarizing film, an unstretched film of a polyvinyl alcohol-based resin film having a thickness of 20 μm to 100 μm, preferably 30 μm to 80 μm is used. Industrially, the width of the film is practically 1500 mm to 4000 mm.
The thickness of the polyvinyl alcohol polarizing film obtained by subjecting this unstretched film to swelling treatment, stretching treatment, dyeing treatment, boric acid treatment, water washing treatment, and finally drying is about 5 to 50 μm, for example.
膨潤工程は、フィルム表面の異物除去、フィルム中の可塑剤除去、次工程での易染色性の付与、フィルムの可塑化などの目的で行われる。処理条件はこれらの目的が達成できる範囲で、かつ基材フィルムの極端な溶解、失透などの不具合が生じない範囲で決定される。未延伸の原反フィルムを、例えば10℃〜50℃、好ましくは20℃〜40℃の水溶液にフィルムを浸漬して行われる。フィルムの浸漬時間は、30秒〜300秒、更に好ましくは60秒〜240秒程度である。 The swelling step is performed for the purpose of removing foreign matter from the film surface, removing the plasticizer in the film, imparting easy dyeability in the next step, and plasticizing the film. The treatment conditions are determined within a range in which these objects can be achieved and within a range in which problems such as extreme dissolution and devitrification of the base film do not occur. For example, the unstretched raw film is immersed in an aqueous solution at 10 ° C to 50 ° C, preferably 20 ° C to 40 ° C. The immersion time of the film is about 30 seconds to 300 seconds, more preferably about 60 seconds to 240 seconds.
膨潤処理工程では、フィルムが幅方向に膨潤してフィルムにシワが入るなどの問題が生じやすいので、エキスパンダーロール、スパイラルロール、クラウンロール、クロスガイダー、ベンドバー、テンタークリップなど公知の拡幅装置でフィルムのシワを取りつつフィルムを搬送することが好ましい。浴中のフィルム搬送を安定化させる目的で、膨潤浴中での水流を水中シャワーで制御したり、EPC装置(Edge Position Control装置:フィルムの端部を検出し、フィルムの蛇行を防止する装置)などを併用したりすることも有用である。本工程では、フィルムの走行方向にもフィルムが膨潤拡大するので、搬送方向のフィルムのたるみを無くすために、例えば処理槽前後の搬送ロールの速度をコントロールするなどの手段を講ずることが好ましい。また、使用する膨潤処理浴は、純水の他、ホウ酸(特開平10−153709号公報に記載)、塩化物(特開平06−281816号公報に記載)、無機酸、無機塩、水溶性有機溶媒、アルコール類などを0.01重量%〜10重量%の範囲で添加した水溶液も使用可能であるが、先に述べた理由により水が好ましい。 In the swelling process, problems such as the film swelling in the width direction and wrinkling into the film are likely to occur. It is preferable to transport the film while removing wrinkles. In order to stabilize the film transport in the bath, the water flow in the swelling bath is controlled with an underwater shower, or an EPC device (Edge Position Control device: a device that detects the edge of the film and prevents meandering of the film) It is also useful to use these together. In this step, since the film swells and expands in the running direction of the film, it is preferable to take measures such as controlling the speed of the transport roll before and after the treatment tank in order to eliminate the slack of the film in the transport direction. In addition to pure water, the swelling treatment bath used is boric acid (described in JP-A-10-153709), chloride (described in JP-A-06-281816), inorganic acid, inorganic salt, water-soluble An aqueous solution to which an organic solvent, alcohol or the like is added in an amount of 0.01 wt% to 10 wt% can be used, but water is preferable for the reason described above.
膨潤処理後、ポリビニルアルコール系フィルムを湿式延伸処理する。この延伸処理では、水100重量部に対し、ホウ酸0.01〜2.0重量部を含む水溶液中でフィルムを1.1倍以上3倍未満の延伸倍率で一軸延伸する。この湿式延伸工程での延伸倍率が上記範囲を外れる場合は染色ムラを低減できなかったり、最終の偏光フィルムの光学特性が十分でなくなったりする。また、湿式延伸工程は1つの浴液で行うだけでなく、複数の浴液を用いた複数工程で連続的に行ってもよいが、その場合でも積算延伸倍率1.1倍以上3倍未満の範囲であるようにする。 After the swelling treatment, the polyvinyl alcohol film is wet-stretched. In this stretching treatment, the film is uniaxially stretched at a draw ratio of 1.1 times or more and less than 3 times in an aqueous solution containing 0.01 to 2.0 parts by weight of boric acid with respect to 100 parts by weight of water. When the draw ratio in the wet drawing step is out of the above range, uneven dyeing cannot be reduced, or the optical properties of the final polarizing film are not sufficient. In addition, the wet stretching step may be performed not only in one bath solution but also continuously in a plurality of steps using a plurality of bath solutions, but even in that case, the cumulative stretching ratio is 1.1 times or more and less than 3 times. Make it a range.
延伸方法としては、例えば浸漬浴の前後に設けたニップロールの周速に差をつけてフィルムを延伸するロール間延伸法が好適に採用されるが、これに限定されるものではなく、従来から知られている各種延伸法が採用可能である。 As the stretching method, for example, an inter-roll stretching method in which the film is stretched by making a difference in the peripheral speed of the nip roll provided before and after the immersion bath is suitably employed, but the present invention is not limited to this and is conventionally known. Various stretching methods can be employed.
この湿式延伸工程で使用される浴液は、水100重量部に対しホウ酸0.01〜2.0重量部を含む水溶液であるが、このようなホウ酸水溶液を使用することにより、シワが入りにくいという利点もある。また、湿式延伸工程で使用される浴液の温度は10℃〜40℃であるのが好ましい。浴液の温度が10℃を下回ると温度制御に大規模な冷却設備が必要となり不経済であり、逆に40℃を超えると原反フィルムが溶解するおそれがある。 The bath liquid used in this wet stretching step is an aqueous solution containing 0.01 to 2.0 parts by weight of boric acid with respect to 100 parts by weight of water. There is also an advantage that it is difficult to enter. Moreover, it is preferable that the temperature of the bath liquid used at a wet extending process is 10 to 40 degreeC. If the temperature of the bath liquid is less than 10 ° C, a large-scale cooling facility is required for temperature control, which is uneconomical. Conversely, if it exceeds 40 ° C, the raw film may be dissolved.
延伸処理後、フィルムの染色が行われる。通常の二色性色素による染色工程は、フィルムに二色性色素を吸着、配向させるなどの目的で行われる。処理条件はこれらの目的が達成できる範囲で、かつ基材フィルムの極端な溶解、失透などの不具合が生じない範囲で決定される。二色性色素としてヨウ素を用いる場合、例えば、10℃〜45℃、好ましくは20℃〜35℃の温度で、かつ重量比でヨウ素/KI/水=0.003〜0.2/0.1〜10/100の濃度で30秒〜600秒、好ましくは60秒〜300秒浸漬処理を行う。ヨウ化カリウムに代えて、他のヨウ化物、例えばヨウ化亜鉛などを用いてもよい。また、他のヨウ化物をヨウ化カリウムと併用しても良い。また、ヨウ化物以外の化合物、例えばホウ酸、塩化亜鉛、塩化コバルトなどを共存させてもよい。ホウ酸を添加する場合、ヨウ素を含む点で下記のホウ酸処理と区別される。水100重量部に対し、ヨウ素を0.003重量部以上含んでいるものであれば染色槽と見なせる。 After the stretching treatment, the film is dyed. The usual dyeing process with a dichroic dye is performed for the purpose of adsorbing and orienting the dichroic dye on the film. The treatment conditions are determined within a range in which these objects can be achieved and within a range in which problems such as extreme dissolution and devitrification of the base film do not occur. When iodine is used as the dichroic dye, for example, iodine / KI / water = 0.003 to 0.2 / 0.1 at a temperature of 10 to 45 ° C., preferably 20 to 35 ° C. and in a weight ratio. The immersion treatment is performed at a concentration of 10/100 for 30 seconds to 600 seconds, preferably 60 seconds to 300 seconds. Instead of potassium iodide, other iodides such as zinc iodide may be used. Other iodides may be used in combination with potassium iodide. Further, 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 boric acid treatment in that it contains iodine. Any dye containing 0.003 parts by weight or more of iodine with respect to 100 parts by weight of water can be regarded as a dyeing tank.
二色性色素として水溶性二色性染料を用いる場合、例えば20℃〜80℃、好ましくは30℃〜70℃の温度で、かつ重量比で二色性染料/水=0.001〜0.1/100の濃度で30秒〜600秒、好ましくは60秒〜300秒浸漬処理を行う。使用する二色性染料の水溶液は、染色助剤などを有していてもよく、例えば硫酸ナトリウムなどの無機塩、界面活性剤などを含有していてもよい。二色性染料は単独でもよいし、2種類以上の二色性染料を同時に用いることもできる。 When a water-soluble dichroic dye is used as the dichroic dye, for example, a temperature of 20 ° C. to 80 ° C., preferably 30 ° C. to 70 ° C., and a weight ratio of dichroic dye / water = 0.001 to 0.001. An immersion treatment is performed at a concentration of 1/100 for 30 seconds to 600 seconds, preferably 60 seconds to 300 seconds. The aqueous solution of the dichroic dye to be used may have a dyeing assistant or the like, and may contain, for example, an inorganic salt such as sodium sulfate, a surfactant or the like. The dichroic dye may be used alone, or two or more dichroic dyes may be used at the same time.
また、膨潤工程と同様に、エキスパンダーロール、スパイラルロール、クラウンロール、クロスガイダー、ベンドバーなどを、染色浴中および/または浴出入り口に設置することもできる。 Similarly to the swelling step, an expander roll, a spiral roll, a crown roll, a cross guider, a bend bar, and the like can be installed in the dyeing bath and / or at the bath entrance / exit.
染色後のホウ酸処理は、水100重量部に対してホウ酸を約1〜10重量部、含有する水溶液に、二色性色素で染色したポリビニルアルコール系フィルムを浸漬することにより行われる。二色性色素がヨウ素の場合、ヨウ化物を約1〜30重量部含有させることが好ましい。
ヨウ化物としてはヨウ化カリウム、ヨウ化亜鉛などが挙げられる。また、ヨウ化物以外の化合物、例えば塩化亜鉛、塩化コバルト、塩化ジルコニウム、チオ硫酸ナトリウム、亜硫酸カリウム、硫酸ナトリウムなどを共存させても良い。
このホウ酸処理は、架橋による耐水化や色相調整(青味がかるのを防止する等)等のために実施される。架橋による耐水化のための場合には、必要に応じて、ホウ酸以外に、またはホウ酸と共に、グリオキザール、グルタルアルデヒドなどの架橋剤も使用することができる。
なお、耐水化のためのホウ酸処理を、耐水化処理、架橋処理、固定化処理などの名称で呼称する場合もある。また、色相調整のためのホウ酸処理を、補色処理、調色処理などの名称で呼称する場合もある。
The boric acid treatment after dyeing is performed by immersing a polyvinyl alcohol film dyed with a dichroic dye in an aqueous solution containing about 1 to 10 parts by weight of boric acid with respect to 100 parts by weight of water. When the dichroic dye is iodine, it is preferable to contain about 1 to 30 parts by weight of iodide.
Examples of iodide include potassium iodide and zinc iodide. Further, compounds other than iodide, such as zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate, etc. may coexist.
This boric acid treatment is carried out for water resistance, hue adjustment (preventing bluishness, etc.) by crosslinking, and the like. In the case of water resistance by cross-linking, a cross-linking agent such as glyoxal or glutaraldehyde can be used in addition to or together with boric acid, if necessary.
In addition, the boric acid treatment for water resistance may be referred to by names such as water resistance treatment, crosslinking treatment, and immobilization treatment. In addition, boric acid treatment for hue adjustment may be referred to by a name such as complementary color processing or toning processing.
このホウ酸処理は、その目的によって、ホウ酸およびヨウ化物の濃度、処理浴の温度を適宜変更して行なわれる。
耐水化のためのホウ酸処理、色相調整のためのホウ酸処理は特に区別されるものではないが、下記の条件で実施される。
原反フィルムを膨潤、染色、ホウ酸処理をする場合で、ホウ酸処理が架橋による耐水化を目的としている時は、水100重量部に対してホウ酸を約3〜10重量部、ヨウ化物を約1〜20重量部含有するホウ酸処理浴を使用し、通常、50℃〜70℃、好ましくは55℃〜65℃の温度で行われる。浸漬時間は、通常、30〜600秒程度、好ましくは60〜420秒、より好ましくは90〜300秒である。
This boric acid treatment is performed by appropriately changing the concentrations of boric acid and iodide and the temperature of the treatment bath according to the purpose.
The boric acid treatment for water resistance and the boric acid treatment for hue adjustment are not particularly distinguished, but are carried out under the following conditions.
When the raw film is swollen, dyed or treated with boric acid, and the boric acid treatment is aimed at water resistance by crosslinking, about 3 to 10 parts by weight of boric acid and 100% by weight of iodide, iodide Is carried out at a temperature of usually 50 ° C to 70 ° C, preferably 55 ° C to 65 ° C. The immersion time is usually about 30 to 600 seconds, preferably 60 to 420 seconds, and more preferably 90 to 300 seconds.
耐水化のためのホウ酸処理後、色相調整のためのホウ酸処理を行っても良い。例えば二色性色素がヨウ素の場合、この目的のためには、水100重量部に対してホウ酸を約1〜5重量部、ヨウ化物を約3〜30重量部含有するホウ酸処理浴を使用し、通常、10℃〜45℃の温度で行われる。浸漬時間は、通常、3〜300秒程度、好ましくは10〜240秒である。
色相調整のためのホウ酸処理は、耐水化のためのホウ酸処理に比べて、通常、低いホウ酸濃度、高いヨウ化物濃度、低い温度で行なわれる。
After boric acid treatment for water resistance, boric acid treatment for hue adjustment may be performed. For example, when the dichroic dye is iodine, for this purpose, a boric acid treatment bath containing about 1 to 5 parts by weight of boric acid and about 3 to 30 parts by weight of iodide for 100 parts by weight of water is used. It is usually used at a temperature of 10 ° C to 45 ° C. The immersion time is usually about 3 to 300 seconds, preferably 10 to 240 seconds.
The boric acid treatment for adjusting the hue is usually performed at a lower boric acid concentration, a higher iodide concentration, and a lower temperature than the boric acid treatment for water resistance.
これらのホウ酸処理は複数の工程で行っても良く、通常、2〜5の工程で行われることが多い。この場合、使用する各ホウ酸処理槽の水溶液組成、温度は上記の範囲内で同じであっても、異なっていてもよい。上記耐水化のためのホウ酸処理、色相調整のためのホウ酸処理をそれぞれ複数の工程で行っても良い。
ホウ酸処理工程においても、染色工程と同様にフィルムの延伸を行ってもよい。最終的な積算延伸倍率は、約4.5〜7.0倍、好ましくは5.0〜6.5倍である。
These boric acid treatments may be performed in a plurality of steps and are usually performed in 2 to 5 steps. In this case, the aqueous solution composition and temperature of each boric acid treatment tank to be used may be the same or different within the above range. The boric acid treatment for water resistance and the boric acid treatment for hue adjustment may be performed in a plurality of steps, respectively.
In the boric acid treatment process, the film may be stretched in the same manner as in the dyeing process. The final cumulative draw ratio is about 4.5 to 7.0 times, preferably 5.0 to 6.5 times.
ホウ酸処理後、水洗処理される。水洗処理は、例えば、耐水化および/または色調調整のためにホウ酸処理したポリビニルアルコール系フィルムを水に浸漬、水をシャワーとして噴霧、あるいは浸漬と噴霧を併用することによって行われる。水洗処理における水の温度は、通常2〜40℃程度であり、浸漬時間は2〜120秒程度であるのがよい。水洗後の乾燥は、乾燥炉中で約40〜100℃の温度で約60〜600秒行われる。 After boric acid treatment, it is washed with water. The water washing treatment is performed, for example, by immersing a polyvinyl alcohol film treated with boric acid for water resistance and / or color tone adjustment in water, spraying water as a shower, or combining immersion and spraying. The temperature of the water in the washing treatment is usually about 2 to 40 ° C., and the immersion time is preferably about 2 to 120 seconds. Drying after washing with water is performed in a drying furnace at a temperature of about 40 to 100 ° C. for about 60 to 600 seconds.
本発明では、上記の膨潤処理後で染色処理前の湿式延伸工程での一軸延伸に加えて、膨潤工程からホウ酸処理工程の間での少なくとも一の工程において一軸延伸を行う。この一軸延伸は、1つの工程で行ってもよいし、2つ以上の工程で行っても良いが、複数の工程で行うことが好ましい。
なお、前記のとおり最終的な積算延伸倍率を約4.5〜7.0倍、好ましくは5.0〜6.5倍とする。
In the present invention, uniaxial stretching is performed in at least one step between the swelling step and the boric acid treatment step in addition to the uniaxial stretching in the wet stretching step after the swelling treatment and before the dyeing treatment. This uniaxial stretching may be performed in one step or may be performed in two or more steps, but is preferably performed in a plurality of steps.
As described above, the final integrated draw ratio is about 4.5 to 7.0 times, preferably 5.0 to 6.5 times.
このようにして製造された偏光フィルムの少なくとも片面に保護フィルムを接着剤で貼合して偏光板が得られる。
保護フィルムとしては、例えば、トリアセチルセルロースやジアセチルセルロースのようなアセチルセルロース系樹脂からなるフィルム、ポリエチレンテレフタレートやポリエチレンナフタレート、ポリブチレンテレフタレートのようなポリエステル系樹脂からなるフィルム、ポリカーボネート系樹脂からなるフィルム、シクロオレフィン系樹脂からなるフィルムが挙げられる。市販の熱可塑性シクロオレフィン系樹脂としては、例えばドイツのティコナ(Ticona)社から販売されている「トパス」(Topas)(商標登録)、ジェイエスアール(株)から販売されている「アートン」(商標登録)、日本ゼオン(株)から販売されている「ゼオノア」や「ゼオネックス」(いずれも商標登録)、三井化学(株)から販売されている「アペル」(商標登録)などがある。このようなシクロオレフィン系樹脂を製膜したものを保護フィルムとすることになるが、製膜には、溶剤キャスト法、溶融押出法など、公知の方法が適宜用いられる。製膜されたシクロオレフィン系樹脂フィルムも市販されており、例えば、積水化学工業(株)から販売されている「エスシーナ」や「SCA40」などがある。
A polarizing plate is obtained by bonding a protective film with an adhesive on at least one side of the polarizing film thus produced.
As the protective film, for example, a film made of an acetyl cellulose resin such as triacetyl cellulose or diacetyl cellulose, a film made of a polyester resin such as polyethylene terephthalate, polyethylene naphthalate or polybutylene terephthalate, or a film made of a polycarbonate resin And a film made of a cycloolefin resin. Examples of commercially available thermoplastic cycloolefin resins include “Topas” (registered trademark) sold by Ticona of Germany and “Arton” (trademark) sold by JSR Co., Ltd. Registered), “ZEONOR” and “ZEONEX” (both registered trademarks) sold by Nippon Zeon Co., Ltd., and “APEL” (trademark registered) sold by Mitsui Chemicals, Inc. A film formed of such a cycloolefin-based resin is used as a protective film. For the film formation, a known method such as a solvent casting method or a melt extrusion method is appropriately used. Formed cycloolefin resin films are also commercially available, such as “Essina” and “SCA40” sold by Sekisui Chemical Co., Ltd.
保護フィルムの厚みは薄いものが好ましいが、薄すぎると、強度が低下し、加工性に劣るものとなり、一方、厚すぎると、透明性が低下したり、積層後に必要な養生時間が長くなったりするなどの問題が生じる。従って、保護フィルムの適当な厚みは、例えば5〜200μm程度であり、好ましくは10〜150μm、より好ましくは20〜100μmである。 The thickness of the protective film is preferably thin. However, if it is too thin, the strength is lowered and the processability is inferior. On the other hand, if it is too thick, the transparency is lowered and the curing time required after lamination is increased. Problems occur. Therefore, the suitable thickness of a protective film is about 5-200 micrometers, for example, Preferably it is 10-150 micrometers, More preferably, it is 20-100 micrometers.
接着剤と偏光フィルム及び/又は保護フィルムとの接着性を向上させるために、偏光フィルム及び/又は保護フィルムに、コロナ処理、火炎処理、プラズマ処理、紫外線照射、プライマー塗布処理、ケン化処理などの表面処理を施してもよい。 In order to improve the adhesiveness between the adhesive and the polarizing film and / or protective film, the polarizing film and / or protective film may be subjected to corona treatment, flame treatment, plasma treatment, ultraviolet irradiation, primer coating treatment, saponification treatment, etc. A surface treatment may be applied.
保護フィルムには、アンチグレア処理、アンチリフレクション処理、ハードコート処理、帯電防止処理、防汚処理などの表面処理が単独或いは組み合わせて施されていても良い。また、保護フィルムおよび/又は保護フィルム表面保護層はベンゾフェノン系化合物、ベンゾトリアゾール系化合物などの紫外線吸収剤や、フェニルホスフェート系化合物、フタル酸エステル化合物などの可塑剤を有していても良い。
かかる保護フィルムは、偏光フィルムの片面に貼合されてもよいし、両面に貼合されてもよい。
The protective film may be subjected to surface treatment such as anti-glare treatment, anti-reflection treatment, hard coat treatment, antistatic treatment, and antifouling treatment alone or in combination. The protective film and / or the protective film surface protective layer may have a UV absorber such as a benzophenone compound or a benzotriazole compound, or a plasticizer such as a phenyl phosphate compound or a phthalate compound.
Such a protective film may be bonded to one side of the polarizing film or may be bonded to both sides.
偏光フィルムと保護フィルムとは、水溶媒系接着剤、有機溶媒系接着剤、ホットメルト系接着剤、無溶剤系接着剤などの接着剤を用いて積層される。水溶媒系接着剤としては例えばポリビニルアルコール系樹脂水溶液、水系二液型ウレタン系エマルジョン接着剤などが、有機溶媒系接着剤としては例えば二液型ウレタン系接着剤などが、無溶剤系接着剤としては例えば一液型ウレタン系接着剤などがそれぞれ挙げられる。偏光フィルムとの接着面をケン化処理などで親水化処理されたアセチルセルロース系フィルムを保護フィルムとして用いる場合、ポリビニルアルコール系樹脂水溶液が接着剤として好適に用いられる。接着剤として用いるポリビニルアルコール系樹脂には、酢酸ビニルの単独重合体であるポリ酢酸ビニルをケン化処理して得られるビニルアルコールホモポリマーのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体をケン化処理して得られるビニルアルコール系共重合体、さらにはそれらの水酸基を部分的に変性した変性ポリビニルアルコール系重合体などがある。この接着剤には、多価アルデヒド、水溶性エポキシ化合物、メラミン系化合物などを添加剤として用いても良い。 The polarizing film and the protective film are laminated using an adhesive such as a water solvent adhesive, an organic solvent adhesive, a hot melt adhesive, or a solventless adhesive. Examples of aqueous solvent adhesives include aqueous polyvinyl alcohol resins and aqueous two-component urethane emulsion adhesives, and examples of organic solvent adhesives include two-component urethane adhesives as solvent-free adhesives. For example, a one-pack type urethane adhesive may be used. When an acetylcellulose-based film whose surface to be bonded to the polarizing film is hydrophilized by saponification or the like is used as a protective film, a polyvinyl alcohol-based resin aqueous solution is suitably used as an adhesive. Polyvinyl alcohol resins used as adhesives include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as other single quantities copolymerizable with vinyl acetate. And vinyl alcohol copolymers obtained by saponifying the copolymer with the polymer, and modified polyvinyl alcohol polymers obtained by partially modifying the hydroxyl groups. For this adhesive, a polyvalent aldehyde, a water-soluble epoxy compound, a melamine compound or the like may be used as an additive.
偏光フィルムと保護フィルムとを貼合する方法は特に限定されるものではなく、例えば偏光フィルム又は保護フィルムの表面に接着剤を均一に塗布し、塗布面にもう一方のフィルムを重ねてロール等により貼合し、乾燥する方法などが挙げられる。 The method for laminating the polarizing film and the protective film is not particularly limited. For example, an adhesive is uniformly applied to the surface of the polarizing film or the protective film, and the other film is stacked on the coated surface by a roll or the like. The method of pasting and drying is mentioned.
通常、接着剤は、調製後、15〜40℃の温度下で塗布され、貼合温度は、通常15〜30℃程度の範囲である。貼合後は乾燥処理を行って、接着剤中に含まれる水などの溶剤を除去するが、この際の乾燥温度は、通常30〜85℃、好ましくは40〜80℃の範囲である。その後、15〜85℃、好ましくは20〜50℃、より好ましくは35〜45℃の温度環境下で、通常1〜90日間程度養生して接着剤を硬化させてもよい。この養生期間が長いと生産性が悪くなるため、養生期間は、1〜30日間程度、好ましくは1〜7日間である。
かくして、接着剤層を介して偏光フィルムの片面又は両面に保護フィルムが貼合された偏光板が得られる。
Usually, an adhesive agent is apply | coated at the temperature of 15-40 degreeC after preparation, and the bonding temperature is the range of about 15-30 degreeC normally. After pasting, a drying treatment is performed to remove a solvent such as water contained in the adhesive, and the drying temperature at this time is usually in the range of 30 to 85 ° C, preferably 40 to 80 ° C. Thereafter, the adhesive may be cured by curing for about 1 to 90 days under a temperature environment of 15 to 85 ° C, preferably 20 to 50 ° C, more preferably 35 to 45 ° C. When this curing period is long, productivity is deteriorated, so the curing period is about 1 to 30 days, preferably 1 to 7 days.
Thus, a polarizing plate in which the protective film is bonded to one side or both sides of the polarizing film through the adhesive layer is obtained.
本発明においては、保護フィルムに、位相差フィルムとしての機能、輝度向上フィルムとしての機能、反射フィルムとしての機能、半透過反射フィルムとしての機能、拡散フィルムとしての機能、光学補償フィルムとしての機能など、光学的機能を持たせることもできる。この場合、例えば保護フィルムの表面に、位相差フィルム、輝度向上フィルム、反射フィルム、半透過反射フィルム、拡散フィルム、光学補償フィルムなどの光学機能性フィルムを積層することにより、このような機能を持たせることができるほか、保護フィルム自体にこのような機能を付与することもできる。また、輝度向上フィルムの機能を持った拡散フィルムなどのように複数の機能を保護フィルム自体に持たせてもよい。 In the present invention, the protective film has a function as a retardation film, a function as a brightness enhancement film, a function as a reflection film, a function as a transflective film, a function as a diffusion film, a function as an optical compensation film, etc. It can also have an optical function. In this case, for example, by laminating an optical functional film such as a retardation film, a brightness enhancement film, a reflection film, a transflective film, a diffusion film, an optical compensation film on the surface of the protective film, it has such a function. In addition, the protective film itself can be provided with such a function. Further, the protective film itself may have a plurality of functions such as a diffusion film having the function of a brightness enhancement film.
例えば、上記の保護フィルムに、特許第2841377号公報、特許第3094113号公報などに記載の延伸処理を施したり、特許第3168850号公報などに記載された処理を施したりすることにより、位相差フィルムとしての機能を付与することができる。また、上記の保護フィルムに、特開 2002-169025号公報や特開 2003-29030 号公報に記載されるような方法で微細孔を形成することにより、また選択反射の中心波長が異なる2層以上のコレステリック液晶層を重畳することにより、輝度向上フィルムとしての機能を付与することができる。上記の保護フィルムに蒸着やスパッタリングなどで金属薄膜を形成することにより、反射フィルム又は半透過反射フィルムとしての機能を付与することができる。上記の保護フィルムに微粒子を含む樹脂溶液をコーティングすることにより、拡散フィルムとしての機能を付与することができる。また、上記の保護フィルムにディスコティック液晶性化合物などの液晶性化合物をコーティングして配向させることにより、光学補償フィルムとしての機能を付与することができる。また、適当な接着剤を用いて、商品名:DBEF(スリーエム(株)製)などの輝度向上フィルム、商品名:WVフィルム(富士写真フィルム(株)製)などの視野角改良フィルム、商品名:スミカライト(商標登録)(住友化学工業(株))などの位相差フィルム、などの市販の光学機能性フィルムを偏光フィルムに直接貼合しても良い。 For example, the above protective film is subjected to a stretching process described in Japanese Patent No. 2841377, Japanese Patent No. 3094113, etc., or a process described in Japanese Patent No. 3168850, etc. The function as can be provided. In addition, by forming micropores in the above protective film by a method as described in JP 2002-169025 A or JP 2003-29030 A, two or more layers having different central wavelengths of selective reflection are formed. By superimposing these cholesteric liquid crystal layers, a function as a brightness enhancement film can be imparted. By forming a metal thin film on the above protective film by vapor deposition or sputtering, a function as a reflective film or a transflective film can be imparted. By coating the protective film with a resin solution containing fine particles, a function as a diffusion film can be imparted. Moreover, the function as an optical compensation film can be provided by coating and aligning liquid crystalline compounds, such as a discotic liquid crystalline compound, on said protective film. In addition, using an appropriate adhesive, a brightness enhancement film such as a product name: DBEF (manufactured by 3M Co., Ltd.), a product name: a viewing angle improving film such as a WV film (manufactured by Fuji Photo Film Co., Ltd.), a product name : Commercially available optical functional films such as retardation films such as Sumikalite (registered trademark) (Sumitomo Chemical Co., Ltd.) may be directly bonded to the polarizing film.
以下、実施例を示して本発明をさらに具体的に説明するが、本発明はこれらの例によって限定されるものではない。
下記実施例、比較例は、ポリビニルアルコールの長尺フィルムを、ニップロールとフリーロールを組み合わせた連続搬送装置で搬送しながら各種処理を行ったものである。延伸は、処理槽前後の駆動ニップロールに周速差をつけて行った。
EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.
In the following Examples and Comparative Examples, various treatments are performed while a long film of polyvinyl alcohol is transported by a continuous transport device that combines a nip roll and a free roll. Stretching was performed with a difference in peripheral speed between the driving nip rolls before and after the treatment tank.
厚さ75μm のポリビニルアルコールフィルム(クラレビニロンVF−PS#7500、重合度2,400 、ケン化度99.9モル%以上 )を30℃の純水に、フィルムが弛まないように緊張状態を保ったまま約130秒間浸漬しフィルムを十分に膨潤させた。ニップロールで水切りを行った後、ホウ酸/水を重量比で0.1/100 の割合で含む30℃の水溶液を入れた浸漬槽に約120秒間浸漬しつつ、この槽中で1.2倍の一軸延伸を行った。次に、ヨウ素/ヨウ化カリウム/水が重量比で0.02/1.5/100 の水溶液に浸漬しつつ、一軸延伸を行った。その後、ヨウ化カリウム/ホウ酸/水が重量比で10/5/100 の水溶液に60℃で約180秒間浸漬、耐水化処理しつつ原反からの積算延伸倍率が5.9倍になるまで一軸延伸を行った。最後に10℃の純水で約10秒間洗浄した後、60℃で2分乾燥して、ヨウ素系偏光フィルムを得た。この偏光フィルムの両面にトリアセチルセルロース(以下、TACという)を貼合して、偏光板とした。 A 75 μm-thick polyvinyl alcohol film (Kurarevinylon VF-PS # 7500, polymerization degree 2,400, saponification degree 99.9 mol% or more) is kept in 30 ° C. pure water so that the film does not loosen. The film was immersed for about 130 seconds to fully swell the film. After draining with a nip roll, it was immersed in an immersion bath containing a 30 ° C. aqueous solution containing boric acid / water at a weight ratio of 0.1 / 100 for about 120 seconds, and 1.2 times in this bath. Was uniaxially stretched. Next, uniaxial stretching was performed while dipping in an aqueous solution of iodine / potassium iodide / water at a weight ratio of 0.02 / 1.5 / 100. After that, it is immersed in an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 10/5/100 at 60 ° C. for about 180 seconds until the cumulative draw ratio from the original fabric reaches 5.9 times while performing water resistance treatment. Uniaxial stretching was performed. Finally, it was washed with pure water at 10 ° C. for about 10 seconds and then dried at 60 ° C. for 2 minutes to obtain an iodine polarizing film. Triacetyl cellulose (hereinafter referred to as TAC) was bonded to both surfaces of this polarizing film to obtain a polarizing plate.
厚さ75μm のポリビニルアルコールフィルム(クラレビニロンVF−PS#7500、重合度2,400 、ケン化度99.9モル%以上 )を30℃の純水に、フィルムが弛まないように緊張状態を保ったまま約130秒間浸漬しフィルムを十分に膨潤させた。ニップロールで水切りを行った後、ホウ酸/水を重量比で0.1/100 の割合で含む30℃の水溶液を入れた浸漬槽に約120秒間浸漬しつつ、この槽中で2.0倍の一軸延伸を行った。次に、ヨウ素/ヨウ化カリウム/水が重量比で0.02/1.5/100 の水溶液に浸漬しつつ、一軸延伸を行った。その後、ヨウ化カリウム/ホウ酸/水が重量比で10/5/100 の水溶液に60℃で約180秒間浸漬、耐水化処理しつつ原反からの積算延伸倍率が5.9倍になるまで一軸延伸を行った。最後に10℃の純水で約10秒間洗浄した後、60℃で2分乾燥して、ヨウ素系偏光フィルムを得た。ついで、実施例1と同様にTACを貼合して偏光板とした。 A 75 μm-thick polyvinyl alcohol film (Kurarevinylon VF-PS # 7500, polymerization degree 2,400, saponification degree 99.9 mol% or more) is kept in 30 ° C. pure water so that the film does not loosen. The film was immersed for about 130 seconds to fully swell the film. After draining with a nip roll, it was immersed in an immersion bath containing a 30 ° C. aqueous solution containing boric acid / water at a weight ratio of 0.1 / 100 for about 120 seconds, and 2.0 times in this bath. Was uniaxially stretched. Next, uniaxial stretching was performed while dipping in an aqueous solution of iodine / potassium iodide / water at a weight ratio of 0.02 / 1.5 / 100. After that, it is immersed in an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 10/5/100 at 60 ° C. for about 180 seconds until the cumulative draw ratio from the original fabric reaches 5.9 times while performing water resistance treatment. Uniaxial stretching was performed. Finally, it was washed with pure water at 10 ° C. for about 10 seconds and then dried at 60 ° C. for 2 minutes to obtain an iodine polarizing film. Next, as in Example 1, TAC was bonded to obtain a polarizing plate.
[比較例1]
厚さ75μm のポリビニルアルコールフィルム(クラレビニロンVF−PS#7500、重合度2,400 、ケン化度99.9モル%以上 )を30℃の純水に、フィルムが弛まないように緊張状態を保ったまま約130秒間浸漬しフィルムを十分に膨潤させた。ニップロールで水切りを行った後、次に、30℃の純水槽に約120秒間浸漬しつつ、この槽中で1.2倍一軸延伸を行った。次に、ヨウ素/ヨウ化カリウム/水が重量比で0.02/1.5/100 の水溶液に浸漬しつつ、一軸延伸を行った。その後、ヨウ化カリウム/ホウ酸/水が重量比で10/5/100 の水溶液に60℃で約180秒間浸漬、耐水化処理しつつ原反からの積算延伸倍率が5.9倍になるまで一軸延伸を行った。最後に10℃の純水で約10秒間洗浄した後、60℃で2分乾燥して、ヨウ素系偏光フィルムを得た。ついで、実施例1と同様にTACを貼合して偏光板とした。
[Comparative Example 1]
A 75 μm-thick polyvinyl alcohol film (Kurarevinylon VF-PS # 7500, polymerization degree 2,400, saponification degree 99.9 mol% or more) is kept in pure water at 30 ° C. so that the film does not loosen. The film was immersed for about 130 seconds to fully swell the film. After draining with a nip roll, the film was then uniaxially stretched 1.2 times in this tank while being immersed in a 30 ° C. pure water tank for about 120 seconds. Next, uniaxial stretching was performed while dipping in an aqueous solution of iodine / potassium iodide / water at a weight ratio of 0.02 / 1.5 / 100. After that, it is immersed in an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 10/5/100 at 60 ° C. for about 180 seconds until the cumulative draw ratio from the original fabric reaches 5.9 times while performing water resistance treatment. Uniaxial stretching was performed. Finally, it was washed with pure water at 10 ° C. for about 10 seconds and then dried at 60 ° C. for 2 minutes to obtain an iodine polarizing film. Next, as in Example 1, TAC was bonded to obtain a polarizing plate.
[比較例2]
厚さ75μm のポリビニルアルコールフィルム(クラレビニロンVF−PS#7500、重合度2,400 、ケン化度99.9モル%以上 )を30℃の純水に、フィルムが弛まないように緊張状態を保ったまま約130秒間浸漬しフィルムを十分に膨潤させた。ニップロールで水切りを行った後、次に、ヨウ素/ヨウ化カリウム/水が重量比で0.02/1.5/100 の水溶液に浸漬しつつ、一軸延伸を行った。その後、ヨウ化カリウム/ホウ酸/水が重量比で10/5/100 の水溶液に60℃で約180秒間浸漬し、耐水化処理しつつ原反からの積算延伸倍率が5.9倍になるまで一軸延伸を行った。最後に10℃の純水で約10秒間洗浄した後、60℃で2分乾燥して、ヨウ素系偏光フィルムを得た。ついで、実施例1と同様にTACを貼合して偏光板とした。
[Comparative Example 2]
A 75 μm-thick polyvinyl alcohol film (Kurarevinylon VF-PS # 7500, polymerization degree 2,400, saponification degree 99.9 mol% or more) is kept in pure water at 30 ° C. so that the film does not loosen. The film was immersed for about 130 seconds to fully swell the film. After draining with a nip roll, the film was then uniaxially stretched while being immersed in an aqueous solution of iodine / potassium iodide / water at a weight ratio of 0.02 / 1.5 / 100. Thereafter, the film is immersed in an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 10/5/100 at 60 ° C. for about 180 seconds, and the integrated draw ratio from the original fabric becomes 5.9 times while water-resistant. Until uniaxial stretching. Finally, it was washed with pure water at 10 ° C. for about 10 seconds and then dried at 60 ° C. for 2 minutes to obtain an iodine polarizing film. Next, as in Example 1, TAC was bonded to obtain a polarizing plate.
[比較例3]
厚さ75μm のポリビニルアルコールフィルム(クラレビニロンVF−PS#7500、重合度2,400 、ケン化度99.9モル%以上 )を30℃の純水に、フィルムが弛まないように緊張状態を保ったまま約130秒間浸漬しフィルムを十分に膨潤させた。次に、30℃のホウ酸/水が重量比で0.1/100 の水溶液を含む浸漬槽処理に約120秒間浸漬しつつ、この槽中で4.0倍一軸延伸を行った。ニップロールで水切りを行った後ヨウ素/ヨウ化カリウム/水が重量比で0.02/1.5/100 の水溶液に浸漬しつつ、一軸延伸を行った。その後、ヨウ化カリウム/ホウ酸/水が重量比で10/5/100 の水溶液に60℃で約180秒間浸漬し、耐水化処理しつつ原反からの積算延伸倍率が5.9倍になるまで一軸延伸を行った。最後に10℃の純水で約10秒間洗浄した後、60℃で2分乾燥して、ヨウ素系偏光フィルムを得た。ついで、実施例1と同様にTACを貼合して偏光板とした。
[Comparative Example 3]
A 75 μm-thick polyvinyl alcohol film (Kurarevinylon VF-PS # 7500, polymerization degree 2,400, saponification degree 99.9 mol% or more) is kept in pure water at 30 ° C. so that the film does not loosen. The film was immersed for about 130 seconds to fully swell the film. Next, 4.0-fold uniaxial stretching was performed in this bath while being immersed in an immersion bath treatment containing an aqueous solution of boric acid / water at 30 ° C. containing 0.1 / 100 by weight for about 120 seconds. After draining with a nip roll, uniaxial stretching was performed while immersing in an aqueous solution of iodine / potassium iodide / water in a weight ratio of 0.02 / 1.5 / 100. Thereafter, the film is immersed in an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 10/5/100 at 60 ° C. for about 180 seconds, and the integrated draw ratio from the original fabric becomes 5.9 times while water-resistant. Until uniaxial stretching. Finally, it was washed with pure water at 10 ° C. for about 10 seconds and then dried at 60 ° C. for 2 minutes to obtain an iodine polarizing film. Next, as in Example 1, TAC was bonded to obtain a polarizing plate.
実施例1、2、比較例1〜3で得られた偏光板の色ムラを暗室で観察した。すなわち、得られた偏光板をクロスニコルに暗室内に配置後、6000cd/m2のバックライト上で色ムラを目視観察した。そして、目視による官能検査で色ムラの大小を1,2,3,4、5の5段階で判定した。評価1は最もムラが少ないことを示しており、評価5は最もムラが多いことを示している。その結果を表1に示す。 Color unevenness of the polarizing plates obtained in Examples 1 and 2 and Comparative Examples 1 to 3 was observed in a dark room. That is, after the obtained polarizing plate was placed in a dark room in crossed Nicol, color unevenness was visually observed on a 6000 cd / m 2 backlight. Then, the degree of color unevenness was determined in five stages of 1, 2, 3, 4, and 5 by visual sensory inspection. Evaluation 1 indicates that there is the least unevenness, and Evaluation 5 indicates that there is the most unevenness. The results are shown in Table 1.
Claims (2)
前記膨潤処理は、前記ポリビニルアルコール系フィルムを水に浸漬することにより行い、
該膨潤処理後で染色処理の前に少なくとも1工程の湿式延伸工程を設け、該延伸工程は、水100重量部に対してホウ酸0.01〜2.0重量部を含む水溶液を用い、前記ポリビニルアルコール系フィルムを該水溶液中で1.1倍以上3倍未満の延伸倍率で一軸延伸することにより行い、
かつ偏光フィルムを得るまでの積算延伸倍率を4.5〜7.0倍の範囲とすることを特徴とする偏光フィルムの製造方法。 A polyvinyl alcohol film is continuously treated in a bath in the order of swelling treatment, dyeing treatment, and boric acid treatment, and at least a dyeing treatment and a boric acid treatment among these treatment steps are uniaxially stretched to obtain a polarizing film. A method for producing a polarizing film, comprising:
The swelling treatment is performed by immersing the polyvinyl alcohol film in water,
Providing at least one step of wet stretching step prior to the dyeing process after the swelling treatment, the stretched process, using an aqueous solution containing 0.01 to 2.0 parts by weight of boric acid relative to 100 parts by weight of water, wherein The polyvinyl alcohol film is uniaxially stretched in the aqueous solution at a draw ratio of 1.1 to 3 times ,
And the manufacturing method of the polarizing film characterized by making the integrated draw ratio until obtaining a polarizing film into the range of 4.5 to 7.0 times .
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JP4697964B2 (en) * | 2006-02-24 | 2011-06-08 | 日東電工株式会社 | Polarizer manufacturing method and cleaning apparatus |
JP5034600B2 (en) * | 2007-03-29 | 2012-09-26 | 住友化学株式会社 | Manufacturing method of polarizing film |
JP4888853B2 (en) | 2009-11-12 | 2012-02-29 | 学校法人慶應義塾 | Method for improving visibility of liquid crystal display device, and liquid crystal display device using the same |
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US10175494B2 (en) | 2011-05-18 | 2019-01-08 | Toyobo Co., Ltd. | Polarizing plate suitable for liquid crystal display device capable of displaying three-dimensional images, and liquid crystal display device |
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