JP3941857B2 - Application method and apparatus - Google Patents

Description

【００３５】
〔実施例２〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B を２００μｍとしたほかは実施例１と同様に実施した。この結果、本実施例２では、減圧度の変動幅は６０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は良好であった。
【００３６】
〔実施例３〕
減圧チャンバー３０のサイドプレート３０ｂとウェブ１２との隙間Ｇ_S1を３００μｍとした他は実施例１と同様に実施した。この結果、本実施例３では、減圧度の変動幅は５０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は非常に良好であった。
【００３７】
〔実施例４〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B 、サイドプレート３０ｂとウェブ１２との隙間Ｇ_S1をともに３００μｍとした他は実施例１と同様に実施した。この結果、本実施例４では、減圧度の変動幅は１０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は良好であった。
【００３８】
〔実施例５〕
減圧チャンバー３０の両側に位置するサイドプレート３０ｂの間の距離がウェブ１２の幅より大きく、サイドプレート３０ｂがバックアップロール１１に対向している場合について実施した。サイドプレート３０ｂとバックアップロール１１との隙間Ｇ_S2は１００μｍに設定した。その他の条件については実施例１と同様に実施した。この結果、減圧度の変動幅は８０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は良好であった。
【００３９】
〔比較例１〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B 、及びサイドプレート３０ｂとウェブ１２との隙間Ｇ_S1をともに５０μｍとした他は実施例１と同様に実施した。この結果、本比較例１では、減圧度の変動幅が１００Ｐａで、塗布１４ｂには段状ムラがあった。
【００４０】
〔比較例２〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B 、サイドプレート３０ｂとウェブ１２との隙間Ｇ_S1をともに９００μｍとした他は実施例１と同様に実施した。この結果、本比較例では、減圧度を１６００Ｐａに設定することができず、塗布が不可能であった。
【００４１】
以上実施例１〜５及び比較例１、２の結果より、バックプレートとウェブとの隙間を先端リップとウェブとの隙間よりも大きく設定することに加え、サイドプレートとウェブあるいはバックアップロールとの隙間をバックプレートとウェブとの隙間以上の大きさにすることが、減圧度の変動幅を抑え、塗膜の段状ムラを抑制するのに効果があることがわかる。さらにバックプレートとウェブとの隙間は、ビード形成に不利でない範囲で、１００μｍ以上に設定することが重要であることがわかる。
【００４２】
〔実施例６〕
ウェブ１２として、膜厚８０μｍのセルローストリアセテート（商品名；フジタック、富士写真フイルム（株）製）を使用し、塗布液を塗布する前に、ウェブ１２の表面に、紫外線硬化性ハードコート組成物（商品名；デソライトＺ−７５２６、７２重量％、ＪＳＲ（株）製）２５０ｇをメチルエチルケトン６２ｇ及びシクロヘキサン８８ｇの混合溶媒に溶解した液を８．６ｍｌ／ｍ² で塗布した。これを１２０℃で５分間乾燥させ、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することにより前記紫外線硬化性組成物を硬化させ、ウェブ１２の表面に厚さ２５μｍのハードコート層を形成した。
【００４３】
塗布液１４として、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と酸化ジルコニウ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、メチルエチルケトンとシクロヘキサンの重量比率が４：６である混合溶液５２ｇに溶解し、この溶液に光重合開始剤（イルガキュア９０７、日本チバガイギー（株）製）１０ｇを加えたものを使用して、走行速度３０ｍ／分で走行させるハードコート層を形成したウェブ１２の上に４．２ｍｌ／ｍ² で塗布した。用いたスロットダイ１３、先端リップ１７とウェブ１２との隙間Ｇ_L 、バックプレート３０ａとウェブ１２との隙間Ｇ_B 及びサイドプレート３０ｂとウェブ１２間の隙間Ｇ_S1については実施例１と同様に実施した。減圧度は１６００Ｐａに設定し、デジタルマノメーターでその変動幅を測定した。この結果、本実施例５では、減圧度の変動幅は８０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は良好であった。
【００４４】
〔実施例７〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B を２００μｍとしたほかは実施例５と同様に実施した。この結果、本実施例では、減圧度の変動幅が６０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は良好であった。
【００４５】
〔実施例８〕
減圧チャンバー３０のサイドプレート３０ｂとウェブ１２との隙間Ｇ_S1を３００μｍとした他は実施例５と同様に実施した。この結果、本実施例では、減圧度の変動幅が５０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は非常に良好であった。
【００４６】
〔実施例９〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B 、サイドプレート３０ｂとウェブ１２との隙間Ｇ_S1をともに３００μｍとした他は実施例５と同様に実施した。この結果、本実施例では、減圧度の変動幅が１０Ｐａで、塗膜１４ｂに段状ムラは認められず、塗膜状態は良好であった。
【００４７】
〔比較例３〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B 、サイドプレート３０ｂとウェブ１２との隙間Ｇ_S1をともに５０μｍとした他は実施例５と同様に実施した。この結果、本比較例では、減圧度の変動幅が１００Ｐａで、塗布１４ｂには段状ムラがあった。
【００４８】
〔比較例４〕
減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間Ｇ_B 、サイドプレート３０ｂとウェブ１２との隙間Ｇ_S1をともに９００μｍとした他は実施例５と同様に実施した。この結果、本比較例では、減圧度を１６００Ｐａに設定することができず、塗布が不可能であった。
【００４９】
以上実施例６〜９及び比較例３、４の結果から、他の塗布系に対しても、バックプレートとウェブとの隙間を、先端リップとウェブとの隙間よりも大きく設定することに加え、サイドプレートとウェブとの隙間をバックプレートとウェブとの隙間以上の大きさにすることで、減圧度の変動幅を抑え、塗膜の段状ムラを抑制する効果を発揮することがわかる。さらにバックプレートとウェブとの隙間は、ビード形成に不利でない減圧度を保持しながら、１００μｍ以上に設定することが重要であることがわかる。
【００５０】
〔実施例１０〕
図４に示すような開放口４０をサイドプレート３０ｂにひとつ設けた。減圧度を１６００Ｐａ、開放口の隙間面積は６０ｍｍ² に設定し、開放口における空気の流入速度は１２０００ｍｍ³ ／秒であった。用いたスロットダイ１３及びウェブ１２、スロットダ１３の設置位置、減圧チャンバー３０のバックプレート３０ａとウェブ１２との隙間、サイドプレートと３０ｂウェブ１２との隙間等、その他の条件については実施例１と同様に実施した。なお、先端リップ１７とウェブ１２、バックプレート３０ａとウェブ１２、サイドプレート３０ｂとウェブ１２の隙間の面積の和は５５ｍｍ² であった。減圧度の変動幅は５０Ｐａであり、得られた塗膜１４ｂには段状のムラが認められず、良好であった。
【００５１】
実施例１０より、先端リップとウェブ、バックプレートとウェブ、サイドプレートとウェブの間にそれぞれ存在する隙間の面積の和よりも大きな面積をもつ隙間を新たに設けることによって、減圧度を安定させることができる。その結果、段状ムラのない塗膜を得ることができることがわかる。
【００５２】
【発明の効果】
以上のように、本発明の塗布装置及び方法により、様々な塗布系で塗膜に段状ムラが発生することなく、塗布を連続的に行うことができる。
【図面の簡単な説明】
【図１】本発明を実施したスロットダイコーターの断面図である。
【図２】本発明を実施したスロットダイ及び周辺装置の斜視図である。
【図３】（Ａ），（Ｂ）ともに、本発明を実施した塗布装置のウェブ及び減圧チャンバーの断面図である。
【図４】本発明のほかの実施形態であるスロットダイ及び周辺装置の斜視図である。
【符号の説明】
１１ バックアップロール
１２ ウェブ
１３ スロットダイ
１７ 先端リップ
３０ 減圧チャンバー
３０ａ バックプレート
３０ｂ サイドプレート
４０ 開放口
Ｇ_B バックプレートとウェブとの隙間
Ｇ_L 先端リップとウェブとの隙間
Ｇ_S1 サイドプレートとウェブとの隙間
Ｇ_S2 サイドプレートとバックアップロールとの隙間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating method and apparatus using a die, and in particular, a photographic photosensitive emulsifier, a magnetic liquid, a liquid imparting antireflection and antiglare properties, a liquid imparting a viewing angle widening effect, and a color filter pigment liquid. A coating method and apparatus for producing a highly functional laminated film by coating a coating liquid such as a surface protection liquid on a flexible support (hereinafter referred to as web) such as a plastic film, paper, or metal foil About.
[0002]
[Prior art]
The high-functional laminated film is manufactured by applying and laminating a coating solution on a web using a slot die coater or a slide bead coater. In recent years, in the production of a highly functional laminated film, there is an increasing demand for a high-precision film thickness control coating technique for each layer constituting the laminated film in order to express a desired function. In application, various disturbances cause a non-uniform coating film thickness phenomenon, generally called stepwise unevenness, and this phenomenon is generally a serious problem as the required film thickness accuracy becomes stricter. It is easy to become.
[0003]
The above step-like unevenness is caused by the pulsation of the coating liquid feeding pump and other liquid feeding systems, resulting in uneven coating liquid supply to the die, uneven web transport speed by the backup roll, It is already known that this is caused by a periodic change in the gap between the tip end portion of the die on the web traveling direction side and the backup roll due to eccentricity. Here, the eccentricity of the backup roll is caused by the fact that the core of the backup roll is not formed and that the backup roll is not strictly a perfect circle.
[0004]
[Problems to be solved by the invention]
By the way, a vacuum chamber is provided between the die and the backup roll in order to stably form a bead. The eccentricity of the backup roll leads to a periodic change in the gap between the vacuum chamber web or the backup roll. Due to the change in the gap, the amount of air leakage around the gap changes periodically, the degree of decompression is not constant, the bead vibrates, and as a result, stepped unevenness of the coating film appears.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a coating method and apparatus for continuously coating on a web, particularly for forming a coating film without stepped unevenness.
[0006]
[Means for Solving the Problems]
The pump pulsation and web conveyance speed unevenness, which are the cause of the above-mentioned stepped unevenness, are problems related to the basic design of the coating equipment, and there is a limit to solve this only by setting the coating conditions in the coating process. There is. Therefore, the present inventors paid attention to the pressure fluctuation due to the eccentricity of the backup roll in order to obtain a uniform film thickness only by the coating process.
[0007]
  In order to achieve the above object, the coating method of the present invention comprises:
(1) A bead is formed from the tip lip of a die of a slot die coater or a slide bead coater close to the web to the web, and the vicinity of the bead is decompressed by a decompression chamber having a back plate, and the above-mentioned on the backup roll In the method of applying the coating liquid to the web, the vacuum chamber has a gap G between the web and the side plate facing the web._S1Is the gap G between the back plate and the web_BInstalled as described above, the back plate is displaced, and the gap G between the web and the back plate_BThe gap G between the tip lip and the web_LLarger than 30μm ≦ G_LWhen ≦ 100 μm, 100 μm ≦ G_B≦ 500μm and 100μm ≦ G_S1≦ 800 μm,100μm <G _L When ≦ 500μm, 200μm ≦ G_B≦ 800μm and 200μm ≦ G_S1≦ 1000μmThe air inside the decompression chamber is continuously sucked and external air is introduced into the decompression chamber from the opening provided in the decompression chamber, and the opening has a clearance area between the web and the tip lip, the web and the back. Having an area larger than the sum of the area of the gap between the plate and the area of the gap between the web or backup roll and the side plate,
(2) A bead is formed from the tip lip of the die of the slot die coater or slide bead coater close to the web to the web, and the vicinity of the bead is depressurized by a decompression chamber having a back plate to form a web on the backup roll. In the method of applying the coating liquid, the decompression chamber has a gap G between the backup roll and the side plate facing the backup roll._S2Is the gap G between the back plate and the web_BInstalled as described above, the back plate is displaced, and the gap G between the web and the back plate_BThe gap G between the tip lip and the web_LLarger than 30μm ≦ G_LWhen ≦ 100 μm, 100 μm ≦ G_B≦ 500μm and 100μm ≦ G_S2≦ 800 μm,100μm ≦ G _L When ≦ 500μm, 200μm ≦ G_B≦ 800μm and 200μm ≦ G_S2≦ 1000μmThe air inside the decompression chamber is continuously sucked and external air is introduced into the decompression chamber from the opening provided in the decompression chamber, and the opening has a clearance area between the web and the tip lip, the web and the back. Having an area larger than the sum of the area of the gap between the plate and the area of the gap between the web or backup roll and the side plate,
Are each configured as a feature.
[0009]
  In addition, this departureMing is on the webA bead is formed from the tip lip of the die of the adjacent slot die coater or slide bead coater to the web, and the vicinity of the bead is decompressed by a decompression equipment having a decompression chamber having a back plate and a side plate. In the coating apparatus that coats the coating liquid, the decompression chamber is provided with an opening through which air outside the decompression chamber flows into the interior during decompression, and this opening is formed between the tip lip and the web. The opening has an area larger than the sum of the area of the gap, the area of the gap between the side plate and the web or the backup roll, and the area of the gap between the back plate and the web, and the opening is an opening of the opening. Having movable plates that change the degree,Features as a configurationHas been.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the coating method of the present invention, coating solutions using various known solvents can be used. For example, water, various halogenated hydrocarbons, alcohols, ethers, esters, ketones and the like can be used alone or in combination.
[0011]
Various known webs can be used as the flexible support. In general, various known plastic films such as polyethylene terephthalate, polyethylene-2,6-naphthalate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, polyamide, paper The surface of the belt-shaped substrate such as various laminated papers coated with α-polyolefins having 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene butene copolymer, etc. on paper, metal foils such as aluminum, copper, and tin In which a preliminary processed layer is formed, or various composite materials in which these are laminated. Further, the optical compensation sheet coating solution, antireflection film coating solution, magnetic coating solution, photographic photosensitive coating solution, surface protection, antistatic or slippery coating solution, etc. are coated on the surface of the web and dried. After that, it may be cut into a desired length and width, and representative examples thereof include, but are not limited to, an optical compensation sheet and an antireflection film.
[0012]
The coating solution preferably has a viscosity of 0.5 to 100 mPa · s and a surface tension of 20 to 70 mN / m at the temperature at the time of coating. The coating speed can be applied in an area of approximately 500 m / min or less.
[0013]
First, the details of the present invention will be described by taking a slot die coater as an example, but the following description also applies to a slide bead coater. FIG. 1 is a sectional view of a coater using a slot die embodying the present invention. The coater 10 is applied to the web 12 supported by the backup roll 11 and continuously applied from the slot die 13 with the coating liquid 14 as a bead 14 a, thereby forming a coating film 14 b on the web 12.
[0014]
Inside the slot die 13, a pocket 15 and a slot 16 are formed. The pocket 15 has a curved section and a straight section, and may be, for example, a substantially circular shape as shown in FIG. 1 or a semicircular shape. The pocket 15 is a liquid storage space for the coating liquid extended in the width direction of the slot die 13 with its cross-sectional shape, and the length of the effective extension is generally equal to or slightly longer than the coating width. The supply of the coating liquid 14 to the pocket 15 is performed from the side surface of the slot die 13 or from the center of the surface opposite to the slot opening 16a. Further, stoppers are provided at both ends of the pocket 15 to prevent the coating liquid 14 from leaking out.
[0015]
The slot 16 is a flow path of the coating liquid 14 from the pocket 15 to the web 12, and has a cross-sectional shape in the width direction of the slot die 13 like the pocket 15, and the opening 16a located on the web side is generally Using a width regulating plate (not shown), the width is adjusted to be approximately the same as the coating width. The angle between the tip of the slot 16 and the tangent in the web traveling direction of the backup roll 11 is preferably 30 ° or more and 90 ° or less.
[0016]
The tip lip 17 of the slot die 13 where the opening 16a of the slot 16 is located is tapered, and the tip is a flat portion 18 called a land. In the land 18, the upstream side in the traveling direction of the web 12 with respect to the slot 16 is referred to as an upstream lip land 18 a and the downstream side is referred to as a downstream lip land 18 b.
[0017]
A decompression chamber having a back plate and a side plate is provided below the tip lip. FIG. 2 is a perspective view showing a slot die and its periphery in a coating process in which the present invention is implemented. The decompression chamber 30 is installed on the side opposite to the traveling direction side of the web 12 at a position where the decompression chamber 30 is not in contact with the bead 14a (see FIG. 1) so that sufficient decompression adjustment can be performed. The decompression chamber 30 includes a back plate 30a and a side plate 30b for maintaining its operating efficiency, and there are gaps between the back plate 30a and the web 12, and between the side plate 30b and the web 12, respectively.
[0018]
The decompression chamber 30 is connected to the blower 32 by a metal pipe 31 or a flexible hose, and decompression is performed by continuously sucking air inside the decompression chamber 30. A valve 33 that adjusts the degree of decompression may be installed between the decompression chamber 30 and the blower 32, or the degree of decompression may be adjusted by controlling the rotational speed of the blower 32. Further, a buffer 34 may be provided between the decompression chamber 30 and the blower 32 to reduce the influence of pressure fluctuation. The degree of pressure reduction can be adjusted by providing a valve (not shown) in the buffer 34. In any case, the effect of the present invention is uniquely determined by the gap around the decompression chamber 30, and the effect is not affected by the decompression equipment for realizing the degree of decompression.
[0019]
3A and 3B are cross-sectional views showing the decompression chamber 30 and the web 12 that are close to each other. The back plate 30a may be integrated with the chamber main body as shown in (A), or may have a structure fastened to the chamber with screws 30c so that the gap can be changed as appropriate as shown in (B). . In any structure, the gap G between the back plate 30a and the web 12_BIt is defined as That is, when the decompression chamber 30 is installed below the web 12 and the slot die 13 as shown in FIG. 2, the gap from the uppermost end of the back plate 30a to the web 12 is shown.
[0020]
Further, the side plate 30b may be integrated with the decompression chamber body as shown in FIGS. 3A and 3B, or may be screwed to the decompression chamber body to provide a gap G between the web and the backup roll._S1, G_S2May be adjustable. When the distance between the side plates on the both ends is smaller than the width of the web, the side plate 30b faces the web 12, and therefore the portion that is actually opened between the side plate 30b and the web 12 is a gap G._S1And Further, when the distance between the side plates on both side ends is larger than the width of the web 12, the side plate 30 b faces the backup roll 11 instead of the web 12, and in this case, between the side plate 30 b and the backup roll 11. Gap G_S2It is defined as
[0021]
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BIs the gap G between the tip lip 17 and the web 12_LIt is preferable to set it to be larger. Since these two gaps respond directly to the eccentricity of the backup roll 11, it is preferable that the fluctuation width of the gap due to the eccentricity is smaller than the total area of the gap. However, since the position of the tip lip 17 is the largest factor for the formation of the bead 14a, the distance from the web 12 is limited. Therefore, in order to adjust the size of the gap, it is preferable to use the back plate 30a, which does not directly affect the coating property, and the gap between the back plate 30a and the web 12 is preferable. G_BIs the gap G between the tip lip 17 and the web 12_LIt is effective as a countermeasure against the eccentricity of the backup roll 11. However, the gap G between the back plate 30 and the web 12_BIf the pressure is widened too much, the pressure reducing capacity of the pressure reducing chamber 30 is lowered, so that there is a limit to naturally widen. The size of each gap is the gap G between the tip lip 17 and the web 12._LIs 30 μm or more and 100 μm or less, the gap G between the back plate 30a and the web 12_BIs preferably 100 μm or more and 500 μm or less, and the gap G between the tip lip 17 and the web 12 is_LIs 100 μm or more and 500 μm or less, the gap G between the back plate 30a and the web 12_BIs preferably 200 μm or more and 800 μm or less.
[0022]
On the other hand, since the side plate 30b of the decompression chamber 30 has an arc shape along the outer peripheral surface of the backup roll 11, a gap G between the side plate 30b and the web on the backup roll 11 is obtained._S1The fluctuation range of the gap G between the back plate 30a and the web 12 is the eccentricity of the backup roll 11._BOr the gap G between the tip lip 17 and the web 12_LNot as direct a response. Therefore, the gap G between the side plate 30 b and the web 12._S1However, the gap G between the side plate 30b and the web 12 is made larger than the gap existing in other parts._S1This is effective because it can increase the influence of the pressure on the degree of pressure reduction. Here, the gap existing in other parts is the gap G between the back plate 30a and the web 12._B, Gap G between tip lip 17 and web 12_LSay.
[0023]
Gap G between back plate 30a and web 12_BIs 100 μm or more and 500 μm or less, and the gap G between the tip lip 17 and the web 12 is_LIs 30 μm or more and 100 μm or less, the gap G between the side plate 30b and the web 12_S1Is preferably 100 μm or more and 800 μm or less, and the gap G between the back plate 30 a and the web 12._BIs 200 μm or more and 800 μm or less, and the gap G between the tip lip 17 and the web 12 is_LIs 100 μm or more and 500 μm or less, the gap G between the side plate 30b and the web 12_S1Is preferably 200 μm or more and 1000 μm or less.
[0024]
Furthermore, this method can be applied even when the position of the side plate 30 b is opposed to the backup roll 11 instead of the web 12. That is, the gap G between the side plate 30b and the backup roll 11_S2In order to increase the influence on the fluctuation of the degree of decompression, the gap should be made larger than the gap existing in the other part.
[0025]
Gap G between back plate 30a and web 12_BIs 100 μm or more and 500 μm or less, and the gap G between the tip lip 17 and the web 12 is_LIs 30 μm or more and 100 μm or less, the gap G between the side plate 30b and the backup roll 11_S2Is preferably 100 μm or more and 800 μm or less, and the gap G between the back plate 30 a and the web 12._BIs 200 μm or more and 800 μm or less, and the gap G between the tip lip 17 and the web 12 is_LIs 100 μm or more and 500 μm or less, the gap G between the side plate 30b and the backup roll 11_S2Is preferably 200 μm or more and 1000 μm or less.
[0026]
Regarding the back plate 30a, it is necessary to install the back plate 30a in a range that does not hinder the proper conveyance of the web 12, that is, in a position where the web 12 is not caught, so that the distance from the web 12 is necessarily limited to some extent. The Within this restriction, the degree of pressure reduction is set in consideration of the viscosity and surface tension of the coating liquid 14, the conveyance speed of the web 12, the wetting of the coating liquid 14 with respect to the web 12, and the like. Therefore, the gap G between the back plate 30a and the web 12 depends on the degree of pressure reduction in the coating system._BNeed to be set. A practical set value in industrial production is preferably 100 μm or more and 1 mm or less. In the case of 1 mm or more, in order to realize a certain degree of decompression, it is necessary to increase the ability of the blower 32 used for decompression. Therefore, it is not realistic in industrial production, and by sucking such a large amount of air around the slot die 13, the air around the coating part is more disturbed to generate wind, which adversely affects the coated surface shape. It is not appropriate from the effect.
[0027]
Another method for suppressing fluctuations in the degree of decompression due to the eccentricity of the backup roll 11 will be described with reference to FIG. Gap G between tip lip 17 and web 12_L, The gap G between the back plate 30a and the web 12_BThe gap G between the side plate 30b and the web 12_S1An opening 40 is provided at a place other than the above. A movable plate 40a is provided so that the size of the opening 40 can be freely set. The movable plate 40a may be fixed with screws 40b as shown in the figure, but is not limited to this as long as the degree of decompression at the opening 40 can be satisfactorily adjusted. The gap G between the side plate 30b and the backup roll 11 when the position of the side plate 30b faces the backup roll 11 instead of the web 12._S2The same applies to the case of.
[0028]
As shown in the figure, when the number of newly provided opening ports 40 is one, the area thereof is made larger, and when plural openings 40 are provided, the sum of the areas is made larger than the total opening area of the three gaps. However, the area must be set within a range in which the degree of decompression that does not affect bead formation can be maintained. That is, the area of the opening 40 and the amount of air flowing in from the gap are considered to be proportional. Although not shown, the amount of air flowing in through the air gap may be obtained by measuring the air inflow speed by installing an anemometer in the vicinity of the opening and calculating the product of the value and the area of the opening 40. In addition, installing the opening 40 near the slot die 13 causes unnecessary wind around the slot die 13 and should be avoided as much as possible. Therefore, the opening 40 may be installed in the pipe 31 between the blower 32 and the decompression chamber 30, and when a buffer 34 is installed between the blower 32 and the decompression chamber 30, it is installed in the buffer 34. May be.
[0029]
The above method is effective for all coating methods in which coating is performed under reduced pressure, except for a coating method using a slot die coater, and is particularly effective for coating by a slide bead coater.
[0030]
【Example】
[Example 1]
The coating apparatus and coating method of the present invention were incorporated into an existing optical compensation sheet manufacturing process. In the optical compensation sheet manufacturing process, the web is fed by a feeder and passes through a rubbing treatment roll while being supported by a guide roll. Thereafter, the coating process of the present invention is incorporated. After that, the basic process is to pass through a drying zone, a heating zone, and an ultraviolet lamp and wind up by a winder.
[0031]
A slot die 13 having an upstream lip land length of 1 mm, a downstream lip land length of 50 μm, an opening of the slot 16 in the web running direction of 150 μm, and a slot 16 length of 50 mm is used. did. Gap G between tip lip 17 and web 12_LWas set to 50 μm. Further, the gap G between the back plate 30 a of the decompression chamber 30 and the web 12_B, And the gap G between the side plate 30b and the web 12_S1Both were set to 100 μm.
[0032]
For the web 12, a cellulose triacetate base material (trade name; Fujitac, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 100 μm was used, and before application of the coating solution, long-chain alkyl-modified polyvinyl alcohol (trade name; Poval MP-203). 2% by weight solution of Kuraray Co., Ltd.)²And dried at 60 ° C. for 1 minute to form an alignment film resin layer. The web 12 on which the alignment layer resin layer was formed in advance was fed, and the surface of the alignment layer resin layer was rubbed to form an alignment layer, which was transported to the coating process as it was for coating. In addition, the rotational peripheral speed of the rubbing roller in the rubbing process is 5.0 m / second, and the pressing pressure against the web 12 is 9.8 × 10.^-3Pa was set.
[0033]
In the coating solution 14, a photopolymerization initiator (trade name; Irgacure 907, manufactured by Ciba Geigy Japan) is added to a mixture of a discotic compound TE- (1) and TE- (2) in a weight ratio of 4: 1. Using a solution containing a liquid crystal compound, which was a 40 wt% methyl ethyl ketone solution added by wt%, the solution was applied to the web 12 conveyed at 50 m / min so as to have a wet film thickness of 5 μm. The degree of vacuum was set to 1600 Pa, and the fluctuation range was measured with a digital manometer. The web 12 coated with the coating solution 14 is passed through a drying zone set at 100 ° C. and a heating zone set at 130 ° C., and an ultraviolet lamp (160 W air-cooled metal halide lamp, Eye Graphics Co., Ltd.) is formed on the liquid crystal layer on the surface. Were used for irradiation with ultraviolet rays. After winding, the stepped unevenness of the coating film 14b was visually inspected. As a result, in this example, the fluctuation range of the degree of reduced pressure was 80 Pa, no stepped unevenness was observed in the coating film 14b, and the coating film state was good.
[0034]
[Chemical 1]

[0035]
[Example 2]
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BWas carried out in the same manner as in Example 1 except that the thickness was set to 200 μm. As a result, in Example 2, the variation range of the degree of reduced pressure was 60 Pa, no stepped unevenness was observed in the coating film 14b, and the coating film state was good.
[0036]
Example 3
Gap G between side plate 30b of decompression chamber 30 and web 12_S1Was carried out in the same manner as in Example 1 except that the thickness was set to 300 μm. As a result, in Example 3, the fluctuation range of the degree of reduced pressure was 50 Pa, no stepped unevenness was observed in the coating film 14b, and the coating film state was very good.
[0037]
Example 4
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BThe gap G between the side plate 30b and the web 12_S1Were carried out in the same manner as in Example 1 except that both were set to 300 μm. As a result, in Example 4, the fluctuation range of the degree of reduced pressure was 10 Pa, the stepped unevenness was not recognized in the coating film 14b, and the coating film state was good.
[0038]
Example 5
This was carried out in the case where the distance between the side plates 30b located on both sides of the decompression chamber 30 was larger than the width of the web 12 and the side plates 30b were opposed to the backup roll 11. Gap G between the side plate 30b and the backup roll 11_S2Was set to 100 μm. Other conditions were the same as in Example 1. As a result, the fluctuation range of the degree of reduced pressure was 80 Pa, stepped unevenness was not recognized in the coating film 14b, and the coating film state was good.
[0039]
[Comparative Example 1]
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_B, And the gap G between the side plate 30b and the web 12_S1Were performed in the same manner as in Example 1 except that both were set to 50 μm. As a result, in Comparative Example 1, the variation range of the degree of reduced pressure was 100 Pa, and the coating 14b had stepped unevenness.
[0040]
[Comparative Example 2]
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BThe gap G between the side plate 30b and the web 12_S1Were performed in the same manner as in Example 1 except that both were set to 900 μm. As a result, in this comparative example, the degree of reduced pressure could not be set to 1600 Pa, and application was impossible.
[0041]
From the results of Examples 1 to 5 and Comparative Examples 1 and 2 above, in addition to setting the gap between the back plate and the web larger than the gap between the tip lip and the web, the gap between the side plate and the web or the backup roll It can be seen that making the size larger than the gap between the back plate and the web is effective in suppressing the fluctuation range of the degree of reduced pressure and suppressing unevenness of the coating film. Furthermore, it can be seen that it is important to set the gap between the back plate and the web to 100 μm or more within a range not disadvantageous for bead formation.
[0042]
Example 6
As the web 12, cellulose triacetate (trade name; Fujitac, manufactured by Fuji Photo Film Co., Ltd.) having a film thickness of 80 μm is used. Trade name: Desolite Z-7526, 72% by weight, manufactured by JSR Corporation) 250 g in a mixed solvent of 62 g of methyl ethyl ketone and 88 g of cyclohexane 8.6 ml / m²It was applied with. This was dried at 120 ° C. for 5 minutes, and the ultraviolet curable composition was cured by irradiating with ultraviolet rays using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.). A hard coat layer having a thickness of 25 μm was formed.
[0043]
As coating solution 14, 91 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) and zirconium oxide dispersion-containing hard coat coating solution (Desolite Z-7401, JSR Corp.) 218 g) was dissolved in 52 g of a mixed solution having a weight ratio of methyl ethyl ketone and cyclohexane of 4: 6, and a solution obtained by adding 10 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Japan) to this solution was used. 4.2 ml / m on the web 12 on which the hard coat layer is to be run at a running speed of 30 m / min.²It was applied with. Slot die 13 used, gap G between tip lip 17 and web 12_L, The gap G between the back plate 30a and the web 12_BAnd the gap G between the side plate 30b and the web 12_S1Was carried out in the same manner as in Example 1. The degree of vacuum was set to 1600 Pa, and the fluctuation range was measured with a digital manometer. As a result, in Example 5, the fluctuation range of the degree of reduced pressure was 80 Pa, the stepped unevenness was not recognized in the coating film 14b, and the coating film state was good.
[0044]
Example 7
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BWas carried out in the same manner as in Example 5 except that the thickness was changed to 200 μm. As a result, in this example, the variation range of the degree of reduced pressure was 60 Pa, no stepped unevenness was observed in the coating film 14b, and the coating film state was good.
[0045]
Example 8
Gap G between side plate 30b of decompression chamber 30 and web 12_S1Was carried out in the same manner as in Example 5 except that the thickness was changed to 300 μm. As a result, in this example, the variation range of the degree of reduced pressure was 50 Pa, no stepped unevenness was observed in the coating film 14b, and the coating film state was very good.
[0046]
Example 9
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BThe gap G between the side plate 30b and the web 12_S1Were carried out in the same manner as in Example 5 except that both were set to 300 μm. As a result, in this example, the fluctuation range of the degree of reduced pressure was 10 Pa, no stepped unevenness was observed in the coating film 14b, and the coating film state was good.
[0047]
[Comparative Example 3]
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BThe gap G between the side plate 30b and the web 12_S1Example 5 was carried out in the same manner as in Example 5 except that both were set to 50 μm. As a result, in this comparative example, the fluctuation range of the degree of reduced pressure was 100 Pa, and the coating 14b had stepped unevenness.
[0048]
[Comparative Example 4]
Gap G between the back plate 30a of the decompression chamber 30 and the web 12_BThe gap G between the side plate 30b and the web 12_S1Were carried out in the same manner as in Example 5 except that both were set to 900 μm. As a result, in this comparative example, the degree of reduced pressure could not be set to 1600 Pa, and application was impossible.
[0049]
From the results of Examples 6 to 9 and Comparative Examples 3 and 4 above, in addition to setting the gap between the back plate and the web larger than the gap between the tip lip and the web for other coating systems, It can be seen that by setting the gap between the side plate and the web to be larger than the gap between the back plate and the web, the fluctuation range of the degree of reduced pressure is suppressed, and the effect of suppressing unevenness of the coating film is exhibited. Furthermore, it can be seen that it is important to set the gap between the back plate and the web to 100 μm or more while maintaining a reduced pressure that is not disadvantageous for bead formation.
[0050]
Example 10
One opening 40 as shown in FIG. 4 is provided in the side plate 30b. Decompression degree is 1600 Pa, open area is 60 mm²The air inflow speed at the opening is 12000mm^Three/ Sec. Other conditions such as the slot die 13 and the web 12 used, the installation position of the slotter 13, the gap between the back plate 30a and the web 12 of the decompression chamber 30, the gap between the side plate and the 30b web 12, and the like are the same as in the first embodiment. Implemented. The sum of the areas of the gaps between the tip lip 17 and the web 12, the back plate 30a and the web 12, and the side plate 30b and the web 12 is 55 mm.²Met. The fluctuation range of the degree of reduced pressure was 50 Pa, and the obtained coating film 14b was good with no step-like unevenness observed.
[0051]
From Example 10, the degree of decompression is stabilized by newly providing a gap having a larger area than the sum of the gap areas existing between the tip lip and the web, the back plate and the web, and the side plate and the web. Can do. As a result, it can be seen that a coating film having no stepped unevenness can be obtained.
[0052]
【The invention's effect】
As described above, by the coating apparatus and method of the present invention, coating can be continuously performed without causing unevenness in the coating film in various coating systems.
[Brief description of the drawings]
FIG. 1 is a sectional view of a slot die coater embodying the present invention.
FIG. 2 is a perspective view of a slot die and peripheral device embodying the present invention.
FIGS. 3A and 3B are cross-sectional views of a web and a vacuum chamber of a coating apparatus embodying the present invention.
FIG. 4 is a perspective view of a slot die and a peripheral device according to another embodiment of the present invention.
[Explanation of symbols]
11 Backup roll
12 Web
13 Slot die
17 Tip lip
30 Vacuum chamber
30a back plate
30b Side plate
40 Open mouth
G_B    Gap between back plate and web
G_L    Clearance between tip lip and web
G_S1    Gap between side plate and web
G_S2    Gap between side plate and backup roll

Claims (3)

A bead is formed from the tip lip of the die of a slot die coater or slide bead coater close to the web to the web, and the vicinity of the bead is depressurized by a decompression chamber having a back plate and applied to the web on a backup roll. In the method of applying the liquid,
The decompression chamber, the gap G _S1 between the side plate opposite to the said web the web is placed so as to be above the gap G _B between the back plate and the web,
The back plate is displaced, and the gap G _B between the web and the back plate, larger than the gap G _L between the said end lip web,
When 30 μm ≦ G _L ≦ 100 μm, 100 μm ≦ G _B ≦ 500 μm and 100 μm ≦ G _S1 ≦ 800 μm, and when 100 μm <G _L ≦ 500 μm, 200 μm ≦ G _B ≦ 800 μm and 200 μm ≦ G _S1 ≦ 1000 μm ,
While continuously sucking the air inside the decompression chamber, external air flows into the decompression chamber from an opening provided in the decompression chamber,
The opening is more than the sum of the area of the gap between the web and the tip lip, the area of the gap between the web and the back plate, and the area of the gap between the web or the backup roll and the side plate. A coating method characterized by having a large area. A bead is formed from the tip lip of the die of a slot die coater or slide bead coater close to the web to the web, and the vicinity of the bead is depressurized by a decompression chamber having a back plate and applied to the web on a backup roll. In the method of applying the liquid,
The decompression chamber is disposed so that a gap G _S2 between the side plates facing the backup roll and the backup roll is equal to or larger than the gap G _B between the back plate and the web,
The back plate is displaced, and the gap G _B between the web and the back plate, larger than the gap G _L between the said end lip web,
When 30 μm ≦ G _L ≦ 100 μm, 100 μm ≦ G _B ≦ 500 μm and 100 μm ≦ G _S2 ≦ 800 μm, and when 100 μm <G _L ≦ 500 μm, 200 μm ≦ G _B ≦ 800 μm and 200 μm ≦ G _S2 ≦ 1000 μm ,
While continuously sucking the air inside the decompression chamber, external air flows into the decompression chamber from an opening provided in the decompression chamber,
The opening is more than the sum of the area of the gap between the web and the tip lip, the area of the gap between the web and the back plate, and the area of the gap between the web or the backup roll and the side plate. A coating method characterized by having a large area. A bead is formed from the tip lip of the die of the slot die coater or slide bead coater close to the web to the web, and the vicinity of the bead is decompressed by a decompression equipment having a decompression chamber having a back plate and a side plate, and is backed up. In an apparatus for applying a coating liquid to the web on a roll,
The decompression chamber is provided with an opening through which air outside the decompression chamber flows into the interior during the decompression,
This opening is more than the sum of the area of the gap between the tip lip and the web, the area of the gap between the side plate and the web or the backup roll, and the area of the gap between the back plate and the web. A coating apparatus having a large area, wherein the opening includes a movable plate that changes an opening degree of the opening.

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