JP2005021749A - Wire bar for coating, manufacturing method for the same and wire bar coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform uniform coating hardly causing strip like or dot like coating nonuniformity even in the coating of a thin layer having ≤20 μm wet coating film thickness, furthermore in the coating of a super thin layer having ≤5 μm. <P>SOLUTION: In a wire bar 12 for coating which is provided with wire lines 42 formed by spirally winding a wire 40 around a round bar-like rod 38 and for applying a coating liquid on a travelling web 16, when the wire bar 12 for coating is expressed as a cylinder circumscribed with the apexes of the respective wire lines 42, the sphericity of the cylinder is controlled to ≤7 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５１】
使用する塗工用ワイヤバー１２は、材質がＳＵＳ３０４であり、塗工用ワイヤバー１２に使用したロッド径及びワイヤ径は図１０の通りである。塗工用ワイヤバー１２は同速で順回転させ、上記の如く調製した塗布液を塗布ヘッド１４から幅６８０ｍｍの配向膜上に塗布した。送液量は１次側マニホールド２６より１分間当たり３．０Ｌを送り、２次側マニホールド２８より１分間当たり０．６Ｌを送った。塗布された塗布膜のウエット膜厚は５μｍである。
【００５２】
ワイヤバー塗布装置１０で塗布液が塗布されたウエブ１６は、１００℃に調整された乾燥ゾーン７６及び、１３０℃に調整された加熱ゾーン７８を通過させてネマチック相を形成した後、この配向膜及び液晶性化合物相が塗布されたウエブ１６を連続搬送しながら、液晶層の表面に紫外線ランプ８０により紫外線を照射した。
【００５３】
そして、ワイヤバー塗布装置１０に設ける塗工用ワイヤバー１２の真円度を試験１から試験９まで（真円度の幅で４．５μｍから３５μｍまで）変えたときに、塗布面状がどのように変わるかを試験した。
【００５４】
塗布面状の評価は、スジ状塗布ムラのスジ本数、点状塗布ムラの点欠陥数から面状判定を行った。スジ本数は製品幅当たり何本あるかを目視でカウントすると共に、点欠陥数は顕微鏡で大きさが１００μｍ以上のものが製品ｍ２ 当たり幾つあるかをカウントした。評価基準は、スジ本数はゼロを合格とし、点欠陥数は５個以下を合格とした。
【００５５】
図１０に、実施例１での試験１〜９の塗工用ワイヤバーの真円度、及び塗工用ワイヤバーの真円度の内訳（ロッド真円度、ワイヤ真円度）、ロッド径、ワイヤ径、及び塗布膜面の評価結果を示した。
【００５６】
試験１は、塗工用ワイヤバー１２の真円度が本発明の真円度（７μｍ以下）を満足しない３５μｍの場合である。
【００５７】
試験２は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足しない１５μｍの場合である。
【００５８】
試験３は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足しない１０μｍの場合である。
【００５９】
試験４は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足する７μｍの場合である。
【００６０】
試験５は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足する６μｍの場合であり、ロッド３８の径を実施例１〜５の８ｍｍから１０ｍｍに変えた場合である。
【００６１】
試験６は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足する６μｍの場合であり、ロッド３８の径を実施例１〜５の８ｍｍから１２ｍｍに変えた場合である。
【００６２】
試験７は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足する４．５μｍの場合であり、ロッド３８の径を実施例１〜５の８ｍｍから５ｍｍに変えた場合である。
【００６３】
試験８は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足する７μｍの場合であり、ワイヤ４０の径を実施例１〜７の８０μｍから５０μｍに変えた場合である。
【００６４】
試験９は、塗工用ワイヤバー１２の真円度が本発明の真円度を満足する６μｍの場合であり、ワイヤ４０の径を実施例１〜７の８０μｍから１００μｍに変えた場合である。
【００６５】
その結果、図１０から分かるように、塗工用ワイヤバー１２の真円度が本発明の上限である７μｍを超えている試験１〜３は何れもスジ本数がゼロにならず、点欠陥数も１０以上と多く、面状判定は不合格の×であった。
【００６６】
これに対し、塗工用ワイヤバー１２の真円度が７μｍ以下の試験４〜９は、何れもスジ本数がゼロであり、点欠陥数も３個以下と少なく、面状判定は合格の○であった。試験４〜９では、ロッド径を５ｍｍ、８ｍｍ、１０ｍｍ、１２ｍｍの４種類、ワイヤ径を５０μｍ、８０μｍ、１００μｍの３種類について行ったが、塗工用ワイヤバーの真円度が７μｍ以下であれば、ロッド径やワイヤ径に関係なく面状判定は合格であった。
【００６７】
ロッド３８の真円度とスジ本数の関係でみた場合、ロッド３８の真円度が５μｍ以下にならないと、スジ本数はゼロにならないことから、塗工用ワイヤバー１２の真円度が７μｍ以下に加えてロッド３８の真円度が５μｍ以下であることが好ましい。また、ワイヤ４０の真円度と点欠陥数の関係でみた場合、ワイヤ４０の真円度が２μｍ以下にならないと、点欠陥数は３個以下にならないことから、塗工用ワイヤバー１２の真円度が７μｍ以下に加えてワイヤ４０の真円度が２μｍ以下であることが好ましい。
（実施例２）
実施例２は、塗工用ワイヤバー１２のロッド改良におけるバニッシング量と塗布ムラとの関係を、光学補償シートの製造及び反射防止膜の製造に適用して試験したものである。試験１〜７は光学補償シートに適用したもので、試験８〜１０は反射防止膜に適用した場合である。尚、光学補償シートの製造ラインのライン条件は実施例１と略同様であるが、使用する塗工用ワイヤバー１２は、材質がＳＵＳ３０４で８ｍｍのものを使用し、センタレス研磨の粗表面加工を施した後、鏡面加工処理をスギノマシン（株）製スパロール装置により、図１１に示したバニッシング量で平滑化を行なった。その後、ワイヤ４０をロッド３８に巻きつけて塗工用ワイヤバー１２を製作した。使用したワイヤ径は８０μｍ、４００μｍ、１５μｍのものを使用した。
【００６８】
試験１は、ロッド３８の鏡面加工のバニッシング量を３０μｍとした場合である。
【００６９】
試験２は、ロッド３８の鏡面加工のバニッシング量を５μｍとした以外は試験１と同様である。
【００７０】
試験３は、ロッドの鏡面加工のバニッシング量を５０μｍとした以外は、実施例１と同様である。
【００７１】
試験４は、ロッドの鏡面加工のバニッシング量を３μｍとした以外は、実施例１と同様である。
【００７２】
試験５は、ロッドの鏡面加工のバニッシング量を７０μｍとした以外は、実施例１と同様である。
【００７３】
試験６は、ロッドの鏡面加工を行わずに、ロッド３８に巻きつけるワイヤ径を４００μｍとした以外は、実施例１と同様である。
【００７４】
試験７は、ロッド３８の鏡面加工のバニッシング量を３０μｍとし、ロッド３８に巻きつけるワイヤ径を１５μｍとした以外は、実施例１と同様である。
【００７５】
試験８は、反射防止膜の場合であり、反射防止膜の製造ライン条件は以下の通りである。
【００７６】
ウエブ１６としては、厚さ８０μｍのトリアセチルセルロース（フジタック、富士写真フイルム（株）製）を使用し、ウエブ１６の表面に、紫外線硬化性ハードコート組成物（デソライトＺ−７５２６、７２重量パーセント、ＪＳＲ（株）製）２５０ｇを６２ｇのメチルエチルケトンおよび８８ｇのシクロヘキサノンに溶解した液をフイルム１ｍ２当り８．６ｍｌ塗布した。その後、１２０°Ｃで５分間乾燥させた後、１６０Ｗ／ｃｍの空冷メタルハライドランプ（アイグラフィックス（株）製）を用いて、紫外線を照射して塗布層を硬化させ厚さ２５μｍハードコート層を形成した。
【００７７】
そして、ハードコート層上に、塗布液としてはジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）９１ｇ、酸化ジルコニューム分散物含有ハードコート塗布液（デソライトＺ−７４０１、ＪＳＲ（株）製）２１８ｇを５２ｇのメチルエチルケトン／シクロヘキサノン＝４０／６０重量パーセントの混合溶媒に溶解した。得られた溶液に光重合開始剤（イルガキュア９０７、（チバガイギ一社）製）１０ｇを加えた塗布液を使用した。この塗布液を走行速度１０ｍ／分で走行するウエブ１６に塗布した。ワイヤバー塗布装置１０の塗工用ワイヤバー１２は、ワイヤ径６０μｍにした以外は実施例１と同じ塗工用ワイヤバーを使ってハードコート層上に塗布した。塗布された塗布膜のウエット膜厚は４μｍである。
【００７８】
試験９は、ロッド３８の鏡面加工のバニッシング量を７０μｍとした以外は、実施例８と同様である。
【００７９】
試験１０は、ロッド３８の鏡面加工のバニッシング量を３μｍとした以外は、実施例８と同様である。
【００８０】
実施例２の中で、試験１〜１０においてそれぞれ作成されたサンプルについて塗布ムラの評価を目視で行ない、その結果を図１１に示す。
【００８１】
塗布ムラの評価において、×は製品出荷不可品、○は製品出荷平均レベル品、◎は優良品、の３段階評価とし、○以上を合格とした。尚、試験７においては、ワイヤ径が１５μｍと細く、塗布途中でワイヤ４０が切断してしまい、サンプル作製ができなかった。
【００８２】
図１１から分かるように、塗工用ワイヤバー１２のロッド３８のバニッシング量には最適な設定値があり、バニッシング量を５〜５０μｍとすることにより、塗布ムラのない塗布膜面状を確保することができる。液晶層においてバニッシング量が３０μｍの場合に特に良い結果となった。
【００８３】
また、試験８〜１０から分かるように、本発明は、ディスコティック液晶層の塗布に限らず、反射防止層の塗布にも適用できた。このことは、本発明の塗工用ワイヤバー１２及びワイヤバー塗布装置１０は、各種の塗布に汎用することできることを意味する。
【００８４】
図１１には示さなかったが、実施例２の塗布ムラの判定結果が、塗布速度に依存するか否かを調べたところ、塗布面状に差はなく、塗布速度には依存していないことを確認した。具体的には、液晶層を塗布する際の搬送速度を１０ｍ／分から２５ｍ／分まで変えて試験を行い、塗布面状に差のないことを確認した。また、反射防止層を塗布する際の搬送速度についても５ｍ／分から１２ｍ／分まで変えて試験を行い、塗布面状に差のないことを確認している。
（実施例３）
実施例３は、塗工用ワイヤバー１２のワイヤ改良におけるステンレス鋼の不純物量及び鋼炉溶解数と塗布ムラとの関係を、光学補償シートの製造及び反射防止膜の製造に適用して試験したものである。試験１〜６は光学補償シートに適用したもので、試験７及び８は反射防止膜に適用した場合である。
【００８５】
光学補償シートの製造ラインのライン条件は実施例２と略同様であるが、塗工用ワイヤバー１２は、ロッド材質がＳＵＳ３０４であり、８ｍｍのものを使用し、センタレス研磨の粗表面加工を施した後、鏡面加工処理をスギノマシン（株）製スパロール装置により、３０μｍのバニッシング量で平滑化を行なった。その後、図１２に示す不純物量及び鋼炉溶解数のスレンレス鋼を伸線して製造したワイヤ４０をロッド３８に巻きつけて塗工用ワイヤバー１２を製作した。ワイヤ４０の線径は８０μｍと１５μｍの２種類を使用した。
【００８６】
また、反射防止膜の製造ラインのライン条件は実施例２と略同様であり、使用した塗工用ワイヤバー１２はワイヤ径を６０μｍにした以外は光学補償シートでの塗工用ワイヤバー１２と同様である。
【００８７】
試験１は、鋼炉溶解を２回行ってステンレス鋼の不純物量を本発明の不純物量（５００ｐｐｍ以下）を満足する３００ｐｐｍとし、このステンレス鋼を伸線して線径が８０μｍのワイヤ４０をロッド３８に巻回した。
【００８８】
試験２は、鋼炉溶解を１回行ってステンレス鋼の不純物量を本発明の不純物量を満足しない６００ｐｐｍとした以外は試験１と同様である。
【００８９】
試験３は、鋼炉溶解を３回行ってステンレス鋼の不純物量を本発明の不純物量を満足する１５０ｐｐｍとした以外は試験１と同様である。
【００９０】
試験４は、鋼炉溶解を２回行って不純物量を本発明の不純物量を満足する上限である５００ｐｐｍとした以外は試験１と同様である。
【００９１】
試験５は、鋼炉溶解を２回行ってステンレス鋼の不純物量を本発明の不純物量を満足する３２０ｐｐｍとし、このステンレス鋼を伸線して線径が１５μｍのワイヤ４０をロッド３８に巻回した。
【００９２】
試験６は、鋼炉溶解を２回行ってステンレス鋼の不純物量を本発明の不純物量を満足する３６０ｐｐｍとした以外は試験１と同様である。
【００９３】
試験７は、反射防止膜に適用した場合であり、鋼炉溶解を２回行ってステンレス鋼の不純物量を本発明の不純物量を満足する３００ｐｐｍとし、このステンレス鋼を伸線して線径が６０μｍのワイヤ４０をロッド３８に巻回した。
【００９４】
試験８は、鋼炉溶解を１回行って不純物量を本発明の不純物量を満足しない６３０ｐｐｍとした以外は試験７と同様である。
【００９５】
実施例３の中で、試験１〜８においてそれぞれ作成されたサンプルについて塗布ムラの評価を目視で行ない、その結果を図１２に示す。
【００９６】
塗布ムラの評価において、×は製品出荷不可品、○は製品出荷平均レベル品、◎は優良品、の３段階評価とし、○以上を合格とした。尚、試験５においては、ワイヤ径が１５μｍと細く、塗布途中でワイヤが切断してしまい、サンプル作製ができなかった。
【００９７】
その結果、図１２から分かるように、ステンレス鋼の不純物量が５００ｐｐｍを超える試験２、８は何れも塗布ムラの判定が×で不合格であるのに対し、ステンレス鋼の不純物量が５００ｐｐｍ以下の試験１、３、４、６、７は何れも塗布ムラの判定が○〜◎で合格であった。特に、ステンレス鋼の不純物量が３００ｐｐｍ以下の試験１と３は◎であり、優良品であった。また、ステンレス鋼の不純物量が５００ｐｐｍ以下を達成したものは、鋼炉溶解数が２回以上のものであり、ワイヤ４０の製造において鋼炉溶解数を２回以上にすることが必要である。
【００９８】
図１２には示さなかったが、ステンレス鋼の不純物量が５００ｐｐｍ以下のものは、ワイヤ４０表面の欠損６２や突起６４の不整部分のバラツキ最大値が０．２％以下であるのに対し、ステンレス鋼の不純物量が６００ｐｐｍ及び６３０ｐｐｍの試験２と８のバラツキ最大値は何れも０．７％と大きかった。
【００９９】
尚、不整部分のバラツキ最大値の測定は、ワイヤ表面（観察可能なワイヤの１／４周分）を入念にレーザー顕微鏡で観察し、欠損６２や突起６４の不整部分の幅と深さ（又は高さ）から不整部分の断面積を算出し、全周分の不整部分の面積を推定するために算出結果を４倍し、それをワイヤ断面積で割って１００倍することにより、ワイヤ単位断面積当たりの不整部分の比率（％）として表した。また、全幅に渡ってワイヤ４０の不整部分を観察評価し、不整部分％のバラツキ最大値とした。
【０１００】
【発明の効果】
以上説明したように、本発明の塗工用ワイヤバー及びその製作方法並びにワイヤバー塗布装置によれば、ウエット塗布膜厚が２０μｍ以下の薄層塗布、更には５μｍ以下の超薄層塗布においても、スジ状ムラや点状ムラの塗布ムラが殆どない均一塗布を行うことができる。
【図面の簡単な説明】
【図１】ワイヤバー塗布装置の全体構成を説明する断面図
【図２】塗工用ワイヤバーを説明する部分拡大断面図
【図３】塗工用ワイヤバーの真円度を説明する説明図
【図４】ワイヤ列の整列乱れの原因となるロッド表面の不整部分を説明する説明図
【図５】バニッシング装置を説明する概念図
【図６】バニッシング加工とバニッシング量の説明図
【図７】ワイヤ表面の不整部分を説明する説明図
【図８】ワイヤ製造の伸線工程及びワイヤの母材であるスレンレス鋼の製造工程を説明する工程図
【図９】光学補償フィルムの製造ラインを説明する説明図
【図１０】塗工用ワイヤバーの真円度と塗布ムラとの関係を説明する説明図
【図１１】塗工用ワイヤバーのロッドのバニッシング量と塗布ムラとの関係を説明する説明図
【図１２】塗工用ワイヤバーのワイヤの不純物量と塗布ムラとの関係を説明する説明図
【符号の説明】
１０…ワイヤバー塗布装置、１２…塗工用ワイヤバー、１４…塗布ヘッド、１６…ウエブ、１８…ガイドローラ、２０…バックアップ部材、２２，２４…コーターブロック、２６，２８…マニホールド、３０，３２…スロット、３４…１次側塗布ビード、３６…２次側塗布ビード、３８…ロッド、４０…ワイヤ、４２…ワイヤ列、４４…塗工用ワイヤバーの真円度のための仮想の円柱、４６…ロッドの欠損、４８…ロッドの突起、５０…ワイヤ列の隙間、５２…バニッシング加工装置、５４…送り側ロッド支持テーブル、５６…ローラ群、５８…受け取り側ロッド支持テーブル、６０…回転ローラ、６２…ワイヤの欠損、６４…ワイヤの突起、６６…送り出し機、６８…ガイドローラ、７０…ラビング処理装置、７２…ラビングローラ、７４…除塵機、７６…乾燥ゾーン、７８…加熱ゾーン、８０…紫外線ランプ、８２…巻取り機、Ｌ１…バニッシング量、Ｌ２…ロッド直径、Ｌ３…ローラ群の仮想内径[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating wire bar, a manufacturing method thereof, and a wire bar coating apparatus, and in particular, an improvement of a coating wire bar for coating a coating liquid on a traveling long support (hereinafter referred to as a web) in a thin layer. About.
[0002]
[Prior art]
There is a wire bar coating device as a device for coating a coating solution on the surface of a continuously running web. This wire bar coating apparatus includes a coating wire bar having a wire array formed by closely winding a wire around a round rod-like rod, and transfers and applies a coating liquid to a traveling web. It is widely used because of its device configuration and the ability to apply thin layers. For example, as an example of thin-layer coating using a coating wire bar, production of an optical functional film such as an optical compensation sheet provided for improving viewing angle characteristics and an antireflection film provided for antireflection in a liquid crystal display device There is.
[0003]
However, in wire bar coating, streaky coating unevenness and dot-shaped coating unevenness formed in the web running direction may occur on the coated film surface of the coated web, and measures by adjusting the physical properties of the coating liquid have been conventionally achieved. However, some improvements have been made to coating wire bars.
[0004]
As a countermeasure against coating unevenness by improving the coating wire bar, for example, in Patent Document 1, a coating layer coated with chrome is applied to the surface of the wire bar in order to adjust the measurement cross section, and the axial direction of the outer diameter of the bar including this coating layer It has been proposed to perform uniform coating by plating so that the variation in the thickness is 1% or less. Further, Patent Document 2 proposes that uniform coating is performed by setting the straightness of the wire bar to 0.025 mm or less per 1 m of the bar length.
[0005]
[Patent Document 1]
JP 2002-282863 A
[0006]
[Patent Document 2]
JP 2001-87697 A
[0007]
[Problems to be solved by the invention]
However, in the case of Patent Document 1, when the wire bar diameter generally used in thin-layer coating is 10 mm, the variation 1% is as large as 100 μm, and the wet coating film thickness is 20 μm or less and is leveled by drying after coating. The coating unevenness cannot be sufficiently solved in the thin layer coating region where the action cannot be expected. In particular, in the field of optical functional films such as optical compensation sheets and antireflection films where the luminance of liquid crystal display devices is increasing and the allowable range of required coating unevenness is narrow, the wet coating thickness is 5 μm or less. It is an area of ultra-thin layer coating, and the actual situation is that uneven coating cannot be prevented if the variation is 1% or less. In this case, even if an attempt is made to reduce the variation to 10 μm level, which is an order of magnitude smaller than 100 μm by the plating process of Patent Document 1, not only the thickness of the plating is uneven, but also the disorder of the alignment of the wires before the plating process becomes uneven in the coating layer. Because it reflects, it is actually difficult.
[0008]
In addition, the straightness of the coating wire bar described in Patent Document 2 mainly affects the unevenness of the coated surface and the unevenness of the thickness in the web width direction, and is insufficient as a measure for preventing streaky or dotted application unevenness. It is.
[0009]
The present invention has been made in view of such circumstances, and even in a thin layer coating having a wet coating thickness of 20 μm or less, and even in an ultrathin layer coating having a thickness of 5 μm or less, there are almost no streaky or spot-shaped coating unevenness. An object of the present invention is to provide a coating wire bar capable of performing uniform coating, a manufacturing method thereof, and a wire bar coating apparatus.
[0010]
[Means for Solving the Problems]
The present inventor has earnestly applied a wire bar for coating that can be applied with almost no coating unevenness even in the case of a thin layer coating having a wet film thickness of 20 μm or less, and further 5 μm or less, as a countermeasure against streak-like or spot-like coating unevenness. As a result of the examination, it was found that if a wire rod for coating having a roundness of 7 μm or less in a state where a wire is wound around a rod can be manufactured, coating can be performed with almost no coating unevenness. Here, the roundness of the coating wire bar in which the wire is wound around the rod is the maximum of the cylinder when the coating wire bar is expressed as a cylinder having an outer peripheral surface circumscribing the apex of each row of the wire row. It is the difference between the diameter and the minimum diameter.
[0011]
Therefore, the inventor investigated the factors that deteriorated the roundness of the wire rod for coating, and found that the variation in the diameter of the rod itself and the wire itself was sufficiently small (for example, the variation could be 1 μm or less). In addition, the inventors have found that defects (such as dents) and irregularities on protrusions (such as burrs) present on the rod surface and wire surface are the main factors that deteriorate the roundness of the coating wire bar. That is, if there is a defect or irregular part of the protrusion on the rod surface, when the wire is wound around the rod, the wire line is disturbed due to the wire climbing on the protrusion or falling into the defect. The roundness of the wire bar for coating deteriorates. Further, the disorder of the alignment of the wire row causes a stripe-shaped unevenness. The irregular surface of the rod surface can be eliminated by applying a mirror finish to the rod surface. By winding the wire after applying a mirror finish to the rod surface, the round shape of the wire rod for coating can be obtained. The degree can be improved.
[0012]
Also, if there is a defect or irregular part of the protrusion on the wire surface, especially the top position of the wire wound with the wire, the roundness of the wire bar for coating will be deteriorated, and the defect or protrusion at the top position of the wire row will be In particular, it causes spot-like unevenness. The irregular portion of the wire surface is related to the amount of impurities contained in the wire. For example, when the wire is stainless steel, the amount of impurities in the stainless steel is reduced to 500 ppm or less, thereby drawing the slenless steel. The irregular portion of the wire obtained in this way can be significantly reduced. In addition, the amount of impurities in stainless steel can be reduced to 500 ppm or less by increasing the number of times of dissolution in the steel furnace in the production process of stainless steel from the conventional one to two or more times.
[0013]
The present invention has been invented based on such knowledge.
[0014]
In order to achieve the above object, a first aspect of the present invention is a coating comprising a wire array in which a wire is spirally closely wound around a round rod-like rod, and a coating solution is applied to a traveling long support. When the wire bar for coating is represented as a columnar shape of the outer peripheral surface circumscribing the apex of each row of the wire row, the roundness of the columnar shape is 7 μm or less. As a result, even in a thin layer coating having a wet coating film thickness of 20 μm or less, and even in an ultrathin layer coating having a thickness of 5 μm or less, uniform coating with almost no stripe-like or spot-like coating unevenness can be performed. In this case, in addition to the roundness of the coating wire bar being 7 μm or less, the straightness of the coating wire bar is preferably 25 μm or less, particularly preferably 10 μm or less. In general, the straightness of the coating wire bar is set to 50 μm or less, but when applied to an ultra-thin layer coating as in the present invention, particularly an organic solvent-based coating, the straightness is 25 μm or less. Further, it is desirable that the thickness be 10 μm or less in order to obtain a high-quality coated surface.
[0015]
A second aspect is characterized in that, in the first aspect, the roundness of the rod is 5 μm or less. This is because the irregularity of the wire array caused by the roundness of the rod is related to the occurrence of streaky coating unevenness on the coating film surface, in addition to the roundness of the coating wire bar being 7 μm or less. This is because, by setting the roundness of the rod to 5 μm or less, it is possible to completely eliminate the occurrence of streaky coating unevenness.
[0016]
A third aspect is characterized in that, in the first or second aspect, the roundness of the wire is 2 μm or less. This is because the roundness of the wire, that is, the size of the irregular portion at the top position of the wire after being wound around the rod, is related to the occurrence of spot-like coating unevenness on the coating film surface, and the trueness of the coating wire bar This is because when the circularity of the wire is 2 μm or less in addition to the circularity of 7 μm or less, the occurrence of streak-like unevenness can be reduced to nearly zero.
[0017]
A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the rod diameter is in a range of 2 to 20 mm, and the wire diameter is 20 to 400 μm. The rod diameter and wire diameter are related to the thickness of the coating film, and in the thin layer coating with a rod diameter or wire diameter in such a range (wet thickness is 20 μm or less, further 5 μm or less), the leveling action after coating is exerted. This is because it cannot be expected and the accuracy of the coating wire bar itself is particularly required.
[0018]
According to a fifth aspect of the present invention, in order to achieve the above object, a coating is provided that includes a wire array in which a wire is spirally wound tightly around a round rod-like rod, and the coating liquid is applied to a traveling long support. In the wire bar manufacturing method, the wire is wound after mirror finishing is applied to the rod surface. This is an improvement in the roundness of the wire bar for coating. It is specified for the coating method by applying a mirror finish to the rod surface and then winding the wire to eliminate the alignment disorder of the wire row. The roundness of the wire bar is improved.
[0019]
A sixth aspect of the present invention according to the fifth aspect is characterized in that the mirror finishing is burnishing and the amount of burnishing is 5 to 50 μm. This is because the polishing method using a grindstone or scouring powder can be considered for mirror finishing, but this polishing method may scrape the originally flat part without irregular parts, so by pressing the roller, the entire rod This is because a burnishing process for smoothing is more preferable.
[0020]
A seventh aspect of the present invention is the method according to the fifth or sixth aspect, wherein the wire is stainless steel, and is obtained by repeatedly melting in the steelmaking furnace in the production process of the stainless steel until the total amount of impurities of the stainless steel is 500 ppm or less. The wire is wound around the rod. Thereby, since the irregular portion of the wire surface can be remarkably reduced, the roundness of the coating wire bar can be further improved.
[0021]
According to an eighth aspect of the present invention, there is provided a coating wire bar manufactured by the coating wire bar manufacturing method according to any one of the fifth to seventh aspects. This defines the characteristics of the wire bar for coating from the manufacturing method.
[0022]
According to a ninth aspect of the present invention, in order to achieve the above object, a coating liquid is applied to a traveling web using the coating wire bar according to any one of the first, second, third, fourth, and eighth aspects. And A ninth aspect of the present invention is configured as a wire bar coating apparatus provided with the coating wire bar of the present invention.
[0023]
A tenth aspect of the present invention is the method according to the ninth aspect, wherein the coating liquid coated with a liquid crystal compound as a component is a liquid crystal layer of an optical compensation sheet, or the coating liquid is coated with a reflection preventing component. The coating film is an antireflection film. This is because the wire bar coating apparatus of the present invention is particularly effective as an apparatus for manufacturing an optical compensation sheet and an antireflection film that require ultra-thin layer coating with a wet coating film thickness of 5 μm or less.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a coating wire bar, a manufacturing method thereof, and a wire bar coating apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.
[0025]
FIG. 1 is a cross-sectional view showing an example of a wire bar coating apparatus 10 according to the present invention, and FIG. 2 is an enlarged cross-sectional view of a coating wire bar 12 provided in the wire bar coating apparatus 10.
[0026]
The wire bar coating device 10 is mainly composed of a coating head 14 and a pair of guide rollers 18 and 18 for guiding the web 16 so as to travel close to the coating wire bar 12.
[0027]
The coating head 14 mainly includes a coating wire bar 12, a backup member 20 that rotatably supports the coating wire bar 12, and coater blocks 22 and 24. Manifolds 26 and 28 and slots 30 and 32 are formed between the backup member 20 and the coater blocks 22 and 24, and the coating liquid is supplied to the manifolds 26 and 28. The coating liquid supplied to the manifolds 26 and 28 is uniformly extruded in the web width direction through the narrow slots 30 and 32. As a result, a primary coating bead 34 is formed on the upstream side (hereinafter referred to as “primary side”) in the feed direction of the web 16 with respect to the coating wire bar 12, and downstream (hereinafter referred to as “secondary side”). The secondary side coated bead 36 is formed. A coating solution is applied to the web 16 that travels through the coating beads 34 and 36.
[0028]
The coating solution supplied excessively from the manifolds 26 and 28 overflows from between the coater blocks 22 and 24 and the web 16 and is collected through a side groove (not shown). The supply of the coating liquid to the manifolds 26 and 28 may be performed from the center part of the manifolds 26 and 28 or from the end part.
[0029]
As shown in FIG. 2, the coating wire bar 12 includes a wire row 42 formed by tightly winding a wire 40 around a round rod-like rod 38, and holds a coating solution in the wire row 42. As a result, the coating liquid is transferred and applied to the traveling web 16. In this case, since the wet thickness of the coating film applied to the web 16 is determined by the diameter of the rod 38 and the diameter of the wire 40, the rod diameter and the wire diameter are determined according to the target thickness of the coating film. For example, in the case of thin layer coating with a wet coating thickness of 20 μm or less, the rod diameter is in the range of 2-20 mm, preferably in the range of 5-10 mm, and the wire diameter is in the range of 20-400 μm, preferably 50-100 μm. Range. As the material of the rod 38 and the wire 40 constituting the coating wire bar 12, various metals such as stainless steel can be used as long as they are satisfactory in strength.
[0030]
In the case of the coating wire bar 12 of the present invention, as shown in FIG. 3, when the coating wire bar 12 is represented as a cylinder 44 having an outer peripheral surface circumscribing the apex of each row of the wire row 42. The circularity of the cylinder 44 is manufactured to be 7 μm or less. As a result, the coating solution is applied so that the coating film applied to the web 16 has a wet film thickness of 20 μm or less, and even an ultra-thin layer coating of 5 μm or less hardly causes streak-like or spot-like coating unevenness. It can be applied to the web 16.
[0031]
Next, the improvement point of the rod 38 and the wire 40 is demonstrated about the manufacturing method of the wire bar 12 for coating of this invention. An example of the material of the wire 40 is stainless steel.
[0032]
First, the improvement of the rod 38 will be described. In the process of manufacturing the coating wire bar 12, the surface of the rod 38 is mirror-finished, and the wire 40 is wound around the rod 38 thus obtained. As shown in FIG. 4, if there is an irregular portion of the defect 46 or the protrusion 48 on the surface of the rod 38, when the wire 40 is wound around the rod 38, This is because disorder of the alignment of the wire row 42 occurs due to the falling of the wire and the roundness of the coating wire bar 12 is deteriorated. Further, this is because the alignment disorder of the wire row 42 causes streaky irregularities.
[0033]
FIG. 4A shows that the wire 40 is forcibly attracted and wound when the wire 40 is wound due to the protrusions 48 existing on the surface of the rod 38, and the gap 50 is interposed between the rows of the wire rows 42. It is the figure which has occurred. FIG. 4B is a diagram in which the wire 40 rides on the protrusion 48 when the wire 40 is wound due to the acute protrusion 48 existing on the surface of the rod 38, and the wire 40 thus protruded protrudes from the wire row 42. It is. In FIG. 4C, due to the defect 46 (dent flaw) existing on the surface of the rod 38, the wire 40 is pinched by the dent flaw when the wire 40 is wound, and the pinched wire 40 is immersed from the wire row 42. It is a figure.
[0034]
In order to eliminate the above-described disorder of the alignment of the wire rows 42, it is important to smooth the rod 38 as a base, and it is optimal to perform a mirror finish. A polishing method using a grindstone or scouring powder is conceivable for the mirror finishing, but there is a risk that the rod 38 may be evenly flattened, so that the burnishing can be performed by the burnishing apparatus 52 shown in FIGS. Is preferred.
[0035]
FIG. 5 is a schematic diagram showing the overall configuration of the burnishing apparatus 52. The rod 38 is moved from the feed rod support table 54 to a roller group 56 (shown in FIG. 6 as an example in which five rotating rollers 60 are provided). The inserted and burnished rod 38 is received by the receiving rod support table 58. 4 is formed on the surface of the rod 38 by removing the defects 46 and the protrusions 48 shown in FIG. 4, so that the wire rows 42 are aligned when finished as the coating wire bar 12 through the wire winding in the subsequent process. The coating wire bar 12 without disturbance can be produced.
[0036]
As shown in FIG. 6, the burnishing device 52 is a method of uniformly smoothing the entire rod 38 by pressing the rod surface with a plurality of rotating rollers 60, 60... Having high hardness and smooth surfaces. It is most suitable for smoothing the rod of the coating wire bar 12. FIG. 6 is a view of the state in which the rod 38 is burnished as viewed from the feed rod support table 54 side. The burnishing amount L1 is a roller with respect to the diameter L2 of the rod 38 that passes when machining. The dimensional difference of the virtual inner diameter L3 of the group 56 is said. By this burnishing process, a mirror surface state is obtained on the surface of the rod 38, but since the elastic deformation is dominant in the burnishing process, the burnishing amount and the decrease in the rod diameter are generally not equal. In this case, if the burnishing amount is too small, the unevenness correction effect on the surface of the rod 38 is small, and if it is too large, the plastic deformation region is entered, and another unevenness due to the peeling phenomenon occurs. Accordingly, the rod 38 for manufacturing the coating wire bar 12 has an optimum burnishing amount range, specifically, the burnishing amount is preferably in the range of 5 to 50 μm, and more preferably in the range of 15 to 40 μm. A commercially available burnishing device 52 can be preferably used. The material of the rotating roller 60 may be harder than the material of the rod 38, and the material is not limited. As described above, the surface of the rod 38 obtained by the burnishing process under the optimum conditions is mirror-like and can be reduced to ± 1 μm or less when viewed from the average surface roughness (Ra). In addition, since the straightness of the rod 38 also affects the shape of the coated surface, particularly the stepped unevenness, it is preferable to prepare a straightness of 10 μm or less. In the improvement of the rod 38, it is preferable that the roundness of the rod after mirror finishing is 5 μm or less. As a result, streaky coating unevenness can be eliminated. With the current rod manufacturing technology, the variation in the diameter of the rod itself can be made sufficiently small (for example, a variation of 1 μm or less is possible), so by eliminating the defect 46 on the surface of the rod 38 and the irregular portion of the projection 48, The roundness can be 5 μm or less.
[0037]
Next, the improvement of the wire 40 will be described. In the manufacturing process of the wire bar 12 for coating, the steel in the manufacturing process of the stainless steel until the total amount of impurities of the stainless steel that is the base material of the wire 40 becomes 500 ppm or less. The melting in the furnace is repeated twice or more, and the obtained wire 40 is wound around the burnished rod 38. Thereby, since the defect | deletion 62 of the surface of the wire 40 and the irregular part of the processus | protrusion 64 can be reduced notably, the roundness of the wire bar 12 for a coating can be improved and an application | coating nonuniformity can be reduced. As shown in FIG. 7, when there is a defect 62 or an irregular portion of the protrusion 64 on the surface of the wire 40, particularly at the top position of the wire 40 after being wound around the rod 38, the roundness of the coating wire bar 12 is deteriorated. Further, the irregular portion of the top position of the wire 40, particularly in the case of thin layer coating, impairs uniform coating of the coating amount in the width direction of the web 16 and also causes partial coating defects, which are spot-shaped coating on the coating film surface. It becomes uneven. 7A shows a case where the protrusion 64 is present at the top position of the wire 40, and FIG. 7B shows a case where the defect 62 exists at the top position of the wire 40. FIG. Is a case where a defect 62 exists at a lower position of the wire 40.
[0038]
The defect 62 and the irregular portion of the protrusion 64 present on the surface of the wire 40 are often formed by the wire drawing process shown in FIG. In the wire drawing process, a rough wire is usually drawn through a stainless steel base to a diamond die, and then the final wire drawing is performed up to the target wire diameter of 40, and the wire is drawn in the process of thinning the stainless base material. A new interface of stainless steel base material appears. At that time, in a stainless steel base material having a large amount of impurities (for example, a large number of grain interfaces or a large number of void spaces mixed with gas), irregular portions of the defect 62 and the protrusion 64 are likely to be formed. Therefore, it is important to manufacture the wire 40 by drawing a stainless steel base material with a small amount of impurities, but reducing the amount of impurities by increasing the number of stainless steel melting steps for manufacturing the stainless steel base material. Can do.
[0039]
FIG. 8B shows a manufacturing process by single melting of stainless steel, in which a stainless steel base material is manufactured through an arc melting process, a casting process, and a heating / rolling process. However, in the single melting manufacturing method, it is usually impossible to reduce the total impurity amount of the stainless steel base material to 500 ppm or less, and defects 62 and irregular portions of the protrusions 64 are formed on the surface of the wire 40 in the wire drawing process described above. End up. On the other hand, the wire 40 used for the coating wire bar 12 of the present invention was manufactured by the double melting manufacturing method of FIG. 8C or the triple melting manufacturing method of FIG. 8D. As a result, in the wire drawing process, defects 62 and irregular portions of the protrusions 64 are hardly formed on the surface of the wire 40. The degree to which impurities in the stainless steel base material are reduced can be measured by the following method. That is, an impurity gas (a gas such as hydrogen, nitrogen, or oxygen contained in stainless steel) among impurities in the stainless steel base material can be measured by a heating / melting infrared absorption method, a heating / melting thermal conductivity method, or the like. Further, non-metallic inclusions among impurities can be quantified by JIS method or ASTM method. Further, the amount of grain boundaries among impurities can be quantified as the amount of grain boundaries per unit cross-sectional area by cutting the wire and directly observing the cross section with a microscope. Since non-metallic inclusions vary greatly depending on the location of the stainless steel base material, it is usually easy to grasp the amount of impure gas as a representative value of the amount of impurities.
[0040]
In the improvement of the wire 40, the roundness of the wire 40 after the improvement is preferably 2 μm or less. Thereby, especially the spot-shaped application | coating nonuniformity can be reduced notably. With the current wire manufacturing technology, the variation in the diameter of the wire itself can be sufficiently small (for example, the variation can be 1 μm or less), and therefore by eliminating the defect 62 on the surface of the wire 40 and the irregular portion of the protrusion 64, It becomes possible to make the roundness 2 μm or less. In order to manufacture the coating wire bar 12 having a roundness of 7 μm or less, both the improvement of the rod 38 and the wire 40 are not essential, and the roundness of the coating wire bar 12 is 7 μm or less. If it becomes, either one may be sufficient.
[0041]
By applying the coating liquid to the traveling web 16 with the wire bar coating apparatus 10 provided with the coating wire bar 12 thus manufactured, the wet coating film thickness is 20 μm or less, and further 5 μm or less. Even in ultra-thin layer coating, uniform coating with almost no streak-like or spot-like coating unevenness can be performed. Since the wire bar coating apparatus 10 provided with the coating wire bar 12 is particularly effective for thin layer coating, an ultra-thin layer coating with a wet coating thickness of 5 μm or less is performed. For example, the optical compensation sheet production line shown in FIG. Can be installed.
[0042]
In the optical compensation sheet production line, as shown in FIG. 9, a web 16 on which a polymer layer for forming an alignment film is previously formed is fed from a feeder 66. The web 16 is guided by a roller 68 and fed into a rubbing processing device 70, and the polymer layer is rubbed by a rubbing roller 72. Next, the dust attached to the surface of the web 16 is removed by the dust remover 74. Then, a coating liquid containing disconematic liquid crystal is applied to the web 16 by the wire bar coating device 10. Thereafter, a liquid crystal layer is formed through a drying zone 76 and a heating zone 78. Furthermore, a desired polymer is formed by irradiating the liquid crystal layer with an ultraviolet lamp 80 to crosslink the liquid crystal. The web 16 on which the polymer is formed is wound up by a winder 82. The optical compensation sheet production line needs to be maintained in an atmosphere of high cleanliness, and the entire process from feeding to winding has a cleanness of class 1000 or less, particularly in the coating process, class 100 or less, It is preferable to make it 10 or less, and class 100 or less is preferable in the drying step.
[0043]
The web 16 used in the present invention is generally polyethylene terephthalate, polyethylene-2,6 naphthalate having a width of 0.3 to 5 m, a length of 45 to 10,000 m, and a thickness of 5 to 200 μm, cellulose diacetate, cellulose triacetate, and cellulose acetate. Α-Polyolefins with 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene butene copolymer, etc. are applied to plastic films such as propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, polyamide, and paper. Or the laminated paper, metal foils, such as aluminum, copper, and tin, or what formed the preliminary process layer on the surface of a strip | belt-shaped base material is contained.
[0044]
The coating solution used in the present invention may be any coating solution for forming a coating film on the web 16 and may be any known coating solution. For example, a coating liquid containing liquid crystal or a liquid containing an antireflection component can be used as the coating liquid. The physical properties of the coating solution are low viscosity (usually about 0.5 to 20 mPa · s) in the case of an organic solvent system, but the present invention can be applied to high viscosity coating solutions up to about 100 mPa · s. It is. Further, the surface tension range of the coating liquid is not particularly limited, but is preferably about 180 to 350 μN / cm.
[0045]
In this embodiment, the coating wire bar 12 of the present invention has been described as an example applied to a wire bar coating apparatus 10 that simultaneously applies the coating liquid to the web 16 and measures the coating liquid. The present invention can also be applied to a type of wire bar coating apparatus in which the coating liquid is excessively applied to the web 16 with a precoater and then the excessive amount of the coating liquid is scraped off.
[0046]
【Example】
Next, the Example of the wire bar coating device 10 provided with the wire bar 12 for coating of this invention is described. Examples of the present invention will be described below with reference to an example applied to the production of an optical compensation sheet and / or the production of an antireflection film that require application of an ultrathin layer, but the present invention is not limited thereto.
(Example 1)
In Example 1, the relationship between the roundness of the coating wire bar 12 and coating unevenness was tested in the case of manufacturing an optical compensation sheet, and the line conditions of the optical compensation sheet manufacturing line were as follows. is there.
[0047]
For the web 16, triacetyl cellulose (Fujitack, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 100 μm was used. On the surface of the web 16, long chain alkyl-modified bobar (MP-203, manufactured by Kuraray Co., Ltd.) was used. After applying 25 ml of a 2 weight percent solution per 1 m 2 of web 16, it was dried at 60 ° C. for 1 minute to form an alignment film resin layer. While transporting the web 16 at 20 m / min, the alignment layer was formed by rubbing the surface of the resin layer. The pressing pressure of the rubbing roller 72 in the rubbing process was 10 kgf / cm 2 per cm 2 of the alignment film resin layer, and the rotational peripheral speed was 2.0 m / sec.
[0048]
And the coating liquid was apply | coated using the wire bar coating device 10 on the alignment film obtained by rubbing the resin layer for alignment films.
[0049]
In the coating liquid, a photopolymerization initiator (Irgacure 907, Nippon Ciba Geigy Co., Ltd.) was added to a 4: 1 weight ratio of R (1) and R (2) ([Chemical Formula 1]) of the discotic compound TE-8. )) Was added at 1 weight percent to the mixture. This prepared the coating liquid containing the liquid crystalline compound made into the 40 weight% methyl ethyl ketone solution of a mixture.
[0050]
[Chemical 1]

[0051]
The material used for the coating wire bar 12 is SUS304, and the rod diameter and wire diameter used in the coating wire bar 12 are as shown in FIG. The coating wire bar 12 was rotated forward at the same speed, and the coating solution prepared as described above was applied from the coating head 14 onto the alignment film having a width of 680 mm. The amount of liquid fed was 3.0 L per minute from the primary side manifold 26 and 0.6 L per minute was sent from the secondary side manifold 28. The wet film thickness of the applied coating film is 5 μm.
[0052]
The web 16 coated with the coating solution by the wire bar coating apparatus 10 passes through a drying zone 76 adjusted to 100 ° C. and a heating zone 78 adjusted to 130 ° C. to form a nematic phase, and then the alignment film and While continuously transporting the web 16 coated with the liquid crystalline compound phase, the surface of the liquid crystal layer was irradiated with ultraviolet rays by an ultraviolet lamp 80.
[0053]
Then, when the roundness of the coating wire bar 12 provided in the wire bar coating apparatus 10 is changed from Test 1 to Test 9 (from 4.5 μm to 35 μm in roundness width), how the coating surface shape is changed. We tested whether it changed.
[0054]
In the evaluation of the coated surface, the surface condition was determined from the number of streaky coating unevenness and the number of point defects of spotted coating unevenness. The number of streaks was counted visually per product width, and the number of point defects was counted as the number of point defects of 100 μm or more per m 2 of the product with a microscope. Evaluation criteria set the number of streaks to zero, and the number of point defects to five or less.
[0055]
FIG. 10 shows the roundness of the coating wire bar in Tests 1 to 9 in Example 1 and the breakdown of the roundness of the coating wire bar (rod roundness, wire roundness), rod diameter, wire The evaluation results of the diameter and the coating film surface were shown.
[0056]
Test 1 is a case where the roundness of the coating wire bar 12 is 35 μm which does not satisfy the roundness (7 μm or less) of the present invention.
[0057]
Test 2 is a case where the roundness of the coating wire bar 12 is 15 μm which does not satisfy the roundness of the present invention.
[0058]
Test 3 is a case where the roundness of the coating wire bar 12 is 10 μm which does not satisfy the roundness of the present invention.
[0059]
Test 4 is a case where the roundness of the coating wire bar 12 is 7 μm which satisfies the roundness of the present invention.
[0060]
Test 5 is a case where the roundness of the coating wire bar 12 is 6 μm which satisfies the roundness of the present invention, and the diameter of the rod 38 is changed from 8 mm in Examples 1 to 5 to 10 mm.
[0061]
Test 6 is a case where the roundness of the coating wire bar 12 is 6 μm which satisfies the roundness of the present invention, and the diameter of the rod 38 is changed from 8 mm to 12 mm in Examples 1 to 5.
[0062]
Test 7 is a case where the roundness of the coating wire bar 12 is 4.5 μm which satisfies the roundness of the present invention, and the diameter of the rod 38 is changed from 8 mm in Examples 1 to 5 to 5 mm. is there.
[0063]
Test 8 is a case where the roundness of the coating wire bar 12 is 7 μm which satisfies the roundness of the present invention, and the diameter of the wire 40 is changed from 80 μm to 50 μm in Examples 1 to 7.
[0064]
Test 9 is a case where the roundness of the coating wire bar 12 is 6 μm satisfying the roundness of the present invention, and the diameter of the wire 40 is changed from 80 μm of Examples 1 to 7 to 100 μm.
[0065]
As a result, as can be seen from FIG. 10, in Tests 1 to 3 in which the roundness of the coating wire bar 12 exceeds the upper limit of 7 μm of the present invention, the number of streaks is not zero, and the number of point defects is It was as many as 10 or more, and the sheet state determination was an unacceptable x.
[0066]
On the other hand, in the tests 4 to 9 in which the roundness of the coating wire bar 12 is 7 μm or less, the number of streaks is zero, the number of point defects is as small as 3 or less, and the surface condition determination is a pass ○. there were. In Tests 4 to 9, four types of rod diameters of 5 mm, 8 mm, 10 mm, and 12 mm and three types of wire diameters of 50 μm, 80 μm, and 100 μm were performed. If the roundness of the coating wire bar was 7 μm or less, The surface judgment was acceptable regardless of the rod diameter or wire diameter.
[0067]
In view of the relationship between the roundness of the rod 38 and the number of streaks, the roundness of the wire bar 12 for coating is 7 μm or less because the number of streaks does not become zero unless the roundness of the rod 38 is 5 μm or less. In addition, the roundness of the rod 38 is preferably 5 μm or less. Further, in view of the relationship between the roundness of the wire 40 and the number of point defects, the number of point defects does not become 3 or less unless the roundness of the wire 40 becomes 2 μm or less. In addition to the circularity of 7 μm or less, the roundness of the wire 40 is preferably 2 μm or less.
(Example 2)
In Example 2, the relationship between the burnishing amount and coating unevenness in the rod improvement of the coating wire bar 12 was applied to the manufacture of an optical compensation sheet and the manufacture of an antireflection film and tested. Tests 1 to 7 are applied to an optical compensation sheet, and tests 8 to 10 are applied to an antireflection film. The line conditions of the optical compensation sheet production line are substantially the same as in Example 1, but the coating wire bar 12 used is made of SUS304 and 8 mm, and is subjected to rough surface processing by centerless polishing. Then, the mirror surface processing was smoothed by the amount of burnishing shown in FIG. 11 using a Superoll machine manufactured by Sugino Machine Co., Ltd. Thereafter, the wire 40 was wound around the rod 38 to produce the coating wire bar 12. The wire diameters used were 80 μm, 400 μm, and 15 μm.
[0068]
Test 1 is a case where the burnishing amount of mirror finishing of the rod 38 is 30 μm.
[0069]
Test 2 is the same as Test 1 except that the burnishing amount for mirror finishing of the rod 38 is set to 5 μm.
[0070]
Test 3 is the same as Example 1 except that the burnishing amount of the mirror finish of the rod is 50 μm.
[0071]
Test 4 is the same as Example 1 except that the burnishing amount of the mirror finish of the rod is 3 μm.
[0072]
Test 5 is the same as Example 1 except that the burnishing amount for mirror finishing of the rod was set to 70 μm.
[0073]
Test 6 is the same as Example 1 except that the diameter of the wire wound around the rod 38 is set to 400 μm without performing mirror finishing of the rod.
[0074]
Test 7 is the same as Example 1 except that the burnishing amount for mirror finishing of the rod 38 is 30 μm and the wire diameter wound around the rod 38 is 15 μm.
[0075]
Test 8 is a case of an antireflection film, and the production line conditions of the antireflection film are as follows.
[0076]
As the web 16, triacetyl cellulose (Fujitack, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm was used, and an ultraviolet curable hard coat composition (Desolite Z-7526, 72 weight percent, A solution prepared by dissolving 250 g of JSR Co., Ltd. in 62 g of methyl ethyl ketone and 88 g of cyclohexanone was applied to 8.6 ml per 1 m 2 of film. Then, after drying at 120 ° C. for 5 minutes, using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.), the coating layer is cured by irradiating ultraviolet rays to form a 25 μm thick hard coat layer. Formed.
[0077]
On the hard coat layer, 91 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) as a coating solution, a hard coat coating solution containing a zirconium oxide dispersion (Desolite Z) (-7401, manufactured by JSR Corporation) was dissolved in 52 g of a mixed solvent of methyl ethyl ketone / cyclohexanone = 40/60 weight percent. A coating solution in which 10 g of a photopolymerization initiator (Irgacure 907, manufactured by (Ciba-Gaigi)) was added to the obtained solution was used. This coating solution was applied to the web 16 running at a running speed of 10 m / min. The coating wire bar 12 of the wire bar coating apparatus 10 was coated on the hard coat layer using the same coating wire bar as in Example 1 except that the wire diameter was 60 μm. The wet film thickness of the applied coating film is 4 μm.
[0078]
Test 9 is the same as Example 8 except that the burnishing amount for mirror finishing of the rod 38 is set to 70 μm.
[0079]
Test 10 is the same as Example 8 except that the burnishing amount for mirror finishing of the rod 38 is set to 3 μm.
[0080]
In Example 2, the coating unevenness was visually evaluated for the samples prepared in Tests 1 to 10, and the results are shown in FIG.
[0081]
In the evaluation of coating unevenness, x is a non-product shipment product, ○ is a product shipment average level product, ◎ is a good product, and ○ or more is a pass. In Test 7, the wire diameter was as thin as 15 μm, and the wire 40 was cut in the middle of application, so that the sample could not be prepared.
[0082]
As can be seen from FIG. 11, there is an optimum set value for the burnishing amount of the rod 38 of the wire bar 12 for coating. By setting the burnishing amount to 5 to 50 μm, it is possible to ensure a coating film surface shape with no coating unevenness. Can do. Particularly good results were obtained when the burnishing amount in the liquid crystal layer was 30 μm.
[0083]
Further, as can be seen from Tests 8 to 10, the present invention was applicable not only to the application of the discotic liquid crystal layer but also to the application of the antireflection layer. This means that the coating wire bar 12 and the wire bar coating apparatus 10 of the present invention can be used for various applications.
[0084]
Although not shown in FIG. 11, it was examined whether or not the coating unevenness determination result of Example 2 was dependent on the coating speed. As a result, there was no difference in the coating surface shape, and it did not depend on the coating speed. It was confirmed. Specifically, the test was performed by changing the transport speed when applying the liquid crystal layer from 10 m / min to 25 m / min, and it was confirmed that there was no difference in the coated surface. In addition, tests were conducted by changing the conveyance speed when applying the antireflection layer from 5 m / min to 12 m / min, and it was confirmed that there was no difference in the coated surface.
Example 3
In Example 3, the relationship between the amount of impurities of stainless steel and the number of steel furnace melts and coating unevenness in the wire improvement of the coating wire bar 12 was applied to the production of an optical compensation sheet and the production of an antireflection film. It is. Tests 1 to 6 are applied to an optical compensation sheet, and tests 7 and 8 are applied to an antireflection film.
[0085]
The line conditions of the optical compensation sheet production line were substantially the same as in Example 2, but the coating wire bar 12 was made of SUS304 rod material and 8 mm, and was subjected to rough surface processing by centerless polishing. Then, the mirror surface processing was smoothed with a 30 μm burnishing amount using a Superoll machine manufactured by Sugino Machine Co., Ltd. After that, the wire 40 manufactured by drawing the stainless steel having the impurity amount and the number of steel furnace melting shown in FIG. 12 was wound around the rod 38 to manufacture the coating wire bar 12. Two types of wire diameters of 80 μm and 15 μm were used.
[0086]
Further, the line conditions of the production line of the antireflection film are substantially the same as those in Example 2, and the coating wire bar 12 used is the same as the coating wire bar 12 in the optical compensation sheet except that the wire diameter is 60 μm. is there.
[0087]
In test 1, the steel furnace was melted twice, and the amount of impurities in the stainless steel was set to 300 ppm satisfying the amount of impurities of the present invention (500 ppm or less), and this stainless steel was drawn to wire the wire 40 having a wire diameter of 80 μm to the rod. Wound to 38.
[0088]
Test 2 is the same as Test 1 except that the steel furnace is melted once and the amount of impurities in the stainless steel is 600 ppm which does not satisfy the amount of impurities of the present invention.
[0089]
Test 3 is the same as Test 1 except that the steel furnace is melted three times and the amount of impurities in the stainless steel is 150 ppm which satisfies the amount of impurities of the present invention.
[0090]
Test 4 is the same as Test 1 except that the steel furnace is melted twice and the impurity amount is 500 ppm, which is the upper limit that satisfies the impurity amount of the present invention.
[0091]
In test 5, the steel furnace was melted twice to set the impurity amount of the stainless steel to 320 ppm that satisfies the impurity amount of the present invention, and this stainless steel was drawn and the wire 40 having a wire diameter of 15 μm was wound around the rod 38. did.
[0092]
Test 6 is the same as Test 1 except that the steel furnace was melted twice and the amount of impurities in the stainless steel was changed to 360 ppm which satisfied the amount of impurities of the present invention.
[0093]
Test 7 was applied to an antireflection film. The steel furnace was melted twice to set the amount of impurities in the stainless steel to 300 ppm satisfying the amount of impurities of the present invention. A 60 μm wire 40 was wound around the rod 38.
[0094]
Test 8 is the same as Test 7 except that the steel furnace is melted once and the impurity amount is 630 ppm which does not satisfy the impurity amount of the present invention.
[0095]
In Example 3, the coating unevenness was visually evaluated for the samples prepared in Tests 1 to 8, and the results are shown in FIG.
[0096]
In the evaluation of coating unevenness, x is a non-product shipment product, ○ is a product shipment average level product, ◎ is a good product, and ○ or more is a pass. In Test 5, the wire diameter was as thin as 15 μm, and the wire was cut in the middle of application, so that the sample could not be prepared.
[0097]
As a result, as can be seen from FIG. 12, tests 2 and 8 in which the amount of impurities in the stainless steel exceeds 500 ppm failed in the determination of uneven coating, while the amount of impurities in the stainless steel was 500 ppm or less. In each of Tests 1, 3, 4, 6, and 7, the coating unevenness was judged as ◯ to ◎ and passed. In particular, Tests 1 and 3 in which the amount of impurities in the stainless steel was 300 ppm or less were ◎ and were excellent products. In addition, when the amount of impurities in the stainless steel is 500 ppm or less, the number of melting in the steel furnace is two times or more, and in the manufacture of the wire 40, the number of melting in the steel furnace is required to be two or more.
[0098]
Although not shown in FIG. 12, when the amount of impurities in the stainless steel is 500 ppm or less, the maximum variation of the irregularities of the defects 62 and the protrusions 64 on the surface of the wire 40 is 0.2% or less. The variation maximum values of Tests 2 and 8 in which the impurity amount of steel was 600 ppm and 630 ppm were both large as 0.7%.
[0099]
Note that the measurement of the maximum variation of the irregular portion is performed by carefully observing the wire surface (one quarter of the observable wire) with a laser microscope, and the width and depth of the irregular portion of the defect 62 or the protrusion 64 (or By calculating the cross-sectional area of the irregular portion from the height), multiplying the calculated result by four to estimate the area of the irregular portion for the entire circumference, and dividing it by the cross-sectional area of the wire to multiply by 100, It was expressed as a ratio (%) of irregular portions per area. Further, the irregular portion of the wire 40 was observed and evaluated over the entire width, and the maximum variation of the irregular portion% was obtained.
[0100]
【The invention's effect】
As described above, according to the coating wire bar, the manufacturing method thereof, and the wire bar coating apparatus of the present invention, even in the thin layer coating having a wet coating thickness of 20 μm or less, and even in the ultrathin layer coating having a thickness of 5 μm or less, the streak It is possible to perform uniform coating with almost no coating unevenness or spotted unevenness.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating the overall configuration of a wire bar coating apparatus
FIG. 2 is a partially enlarged sectional view for explaining a wire bar for coating.
FIG. 3 is an explanatory diagram for explaining the roundness of a wire bar for coating.
FIG. 4 is an explanatory diagram for explaining an irregular portion of a rod surface that causes disorder in the alignment of wire rows.
FIG. 5 is a conceptual diagram illustrating a burnishing device.
FIG. 6 is an explanatory diagram of burnishing and burnishing amount
FIG. 7 is an explanatory diagram for explaining irregular portions on a wire surface.
FIG. 8 is a process diagram for explaining the wire drawing process for wire manufacture and the process for producing stainless steel, which is the base material of the wire.
FIG. 9 is an explanatory diagram for explaining a production line for an optical compensation film.
FIG. 10 is an explanatory diagram for explaining the relationship between the roundness of a coating wire bar and coating unevenness.
FIG. 11 is an explanatory diagram for explaining the relationship between the amount of burnishing of a rod of a coating wire bar and coating unevenness;
FIG. 12 is an explanatory diagram for explaining the relationship between the wire impurity amount of the coating wire bar and coating unevenness;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Wire bar coating device, 12 ... Wire bar for coating, 14 ... Coating head, 16 ... Web, 18 ... Guide roller, 20 ... Backup member, 22, 24 ... Coater block, 26, 28 ... Manifold, 30, 32 ... Slot 34 ... Primary side coated beads, 36 ... Secondary side coated beads, 38 ... Rod, 40 ... Wire, 42 ... Wire row, 44 ... Virtual cylinder for roundness of coating wire bar, 46 ... Rod 48 ... Rod protrusion, 50 ... Wire row gap, 52 ... Burnishing device, 54 ... Feeding side rod support table, 56 ... Roller group, 58 ... Receiving side rod support table, 60 ... Rotating roller, 62 ... Wire breakage, 64 ... Wire protrusion, 66 ... Feeder, 68 ... Guide roller, 70 ... Rubbing treatment device, 72 ... Rubbing roller, 74 Dust remover, 76 ... drying zone, 78 ... heating zone, 80 ... ultraviolet lamp, 82 ... winder, L1 ... burnishing amount, L2 ... rod diameter, the virtual inner diameter of L3 ... rollers

Claims (10)

In the wire bar for coating, which is provided with a wire row in which a wire is spirally closely wound around a round rod-shaped rod, and the coating liquid is applied to a long supporting body that travels,
When the wire rod for coating is represented as a cylinder having an outer peripheral surface circumscribing the apex of each row of the wire row, the roundness of the column is 7 μm or less. The wire rod for coating according to claim 1, wherein the roundness of the rod is 5 μm or less. The wire bar for coating according to claim 1 or 2, wherein the roundness of the wire is 2 µm or less. The wire rod for coating according to any one of claims 1 to 3, wherein the rod diameter is in a range of 2 to 20 mm, and the wire diameter is 20 to 400 µm. In the manufacturing method of the wire bar for coating, comprising a wire row in which a wire is spirally closely wound around a round rod-like rod, and applying a coating liquid to a long supporting body that travels,
A method of manufacturing a coating wire bar, wherein the rod surface is mirror-finished and then the wire is wound. 6. The method of manufacturing a coating wire bar according to claim 5, wherein the mirror finishing is burnishing and the amount of burnishing is 5 to 50 [mu] m. The wire is stainless steel, and the wire obtained by repeatedly melting in the steel furnace in the production process of the stainless steel is wound around the rod until the total amount of impurities of the stainless steel is 500 ppm or less. The method for producing a coating wire bar according to claim 5 or 6. A wire bar for coating produced by the method for producing a wire bar for coating according to any one of claims 5 to 7. A wire bar coating apparatus for applying a coating liquid to a running web using the wire bar for coating according to any one of claims 1, 2, 3, 4, and 8. In the coating solution, a coating film coated with a liquid crystal compound as a component is a liquid crystal layer of an optical compensation sheet, or a coating film coated with a coating solution containing an antireflection component is an antireflection film. The coating apparatus according to claim 9.

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