JPH0490871A - Bar coating method - Google Patents

Abstract

PURPOSE:To improve the coated thick film parts generated at both end parts in a lateral direction in a relatively easy manner and to maintain the improving effect for a long time by making the diameter of each of both end parts of a bar smaller than that of the central part thereof and providing uncoated part to both side parts of a support and blowing air to the contact part of the bar and the support in a coated part. CONSTITUTION:A bar support member 6 is surrounded by weir members 5, 5' and the coating solution 3 supplied from the liquid supply port 4 provided to a part of the weir member 5 forms the liquid storage part 8 between the bar support member 6 and the weir member 5. A substrate 1 to be coated is horizontally fed in the rotary direction of a bar 2 by a pass roll 14 and a press roll 15 so that the under surface of the substrate 1 comes into contact with the top part of the bar 2. In order to perform uniform coating, the air blown out of a nozzle 21 bringing the substrate 1 and the bar 2 to a close contact state over the entire width of the substrate 1 is sprayed to the contact part of the bar and the support at the end surface parts of the bar. By this method, a coated web or substrate can be prepared in an extremely efficient manner.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to photographic materials such as photographic film and photographic paper, photolithographic materials, magnetic recording materials such as magnetic recording tape, pressure-sensitive recording paper, and heat-sensitive recording paper. It is an improved method for applying a liquid coating composition to a continuously running long flexible support (hereinafter referred to as a web) and discontinuous substrates such as semiconductor wafers, printed circuit boards, glass substrates, etc. in the production of recording materials. The present invention relates to a bar coating method.

[Conventional technology]

A bar coating method in which a coating liquid is supplied so that a liquid pool is formed just before a contact portion of a support that is traveling while being in contact with a rotating bar, and the coating liquid is applied to the support by the bar, Sometimes it is necessary to make the coating width narrower than the support width. For example, in a web-like support, it prevents the applied liquid from spreading from the side of the web and contaminating the pass roll that is touched after application, and in the case of a discontinuous substrate, it holds a part of the substrate in the substrate imaging section after application. It is a contract to do so. For this purpose, the bar diameter at both ends of the bar is made narrower than that in the middle (called a stepped bar), so that the bar contacts the support only on the inside of the support width. It is possible to provide uncoated portions on both sides.

However, when coating is carried out by such a method, there are problems in that thick coating parts occur at both ends of the coated surface in the width direction, resulting in delayed drying and a narrowing of the effective width of the product.

As a method to improve this problem, Japanese Patent Laid-Open No. 60-225669
No. 63-63158 and Japanese Utility Model Publication No. 63-63158 disclose the provision of blades for scraping the coating liquid adhering to both sides of the coating roll. Although these methods all showed a certain effect in improving the thick coating at both ends of the coating width, they were not necessarily sufficient. On the other hand, JP-A-62-7467 discloses a second method in which a means for sucking excess liquid is provided along the end surface of the coating bar, and this method is superior to the first two in terms of preventing thick coating. However, since the suction port is not effective unless it is located very close to the end face of the bar, installation may be difficult, and depending on the nature of the liquid, the suction port may become clogged with dried coating liquid when used for a long time. The problem was that it was easy.

[Problem to be solved by the invention]

The purpose of the present invention is to provide a bar coating method in which uncoated areas are provided on both sides of a support, in which it is relatively easy to improve thick coated areas that occur at both ends in the width direction, and the effect lasts for a long time. do.

[Means to solve the problem]

As a result of analyzing the reason for the occurrence of the above problem, it was found that a part of the liquid in the liquid pool formed just before the contact part between the bar and the support body (-next side) overflowed from the one end of the bar, and the liquid pooled against the one end surface of the bar. It was found that the cause was bypassing to the secondary side by crossing the corner formed on the support surface. It has been found that this problem can be solved by blowing air toward the contact area between the bar and the support at one end or end face of the bar. The present invention has been made based on the above findings.

That is, in the present invention, a rotating bar supplies a coating liquid so that a liquid pool is formed just before the contact portion of a supporting body that is traveling while in contact with the rotating bar, and the coating liquid is applied to the supporting body by the bar. In the bar coating method, by making the bar diameter at both ends of the bar smaller than that at the center, uncoated parts are provided on both sides of the support, and the contact area between the bar and the support in the application area is reduced. To provide a bar coating method characterized by blowing wind at the end.

Next, embodiments of the present invention will be described using the drawings.

FIG. 1 is a schematic diagram showing the bar coating method of the present invention,
FIG. 2 is an enlarged cross-sectional view of the bar coating device of FIG. 1; FIG.

The bar 2 has a bar support member 6 over its entire length or a part thereof.
The bar 2 is horizontally and rotatably supported by the bar 2, and a rotation drive means (not shown) is connected to one end of the bar 2.

The bar support member 6 is surrounded by weir members 5 and 5';
The coating liquid 3 supplied from the liquid supply port 4 provided in a part of the weir member 5 forms a liquid storage portion 8 between the bar support member 6 and the weir member 5. Further, an air blowing nozzle 21 is provided for blowing air toward the end of the contact portion between the bar and the support in the application section. From here, air, nitrogen, etc. are blown out to create a wind.

The substrate 1 to be coated is conveyed horizontally by a bath roll 14 and a suppression roll 15 in the direction of rotation of the bar 2 so that the lower surface of the substrate 1 contacts the top of the bar 2.

In FIG. 2, a rotating bar 2 draws up a coating liquid 3 from a liquid reservoir 8 and transfers the coating liquid 3 to the lower surface of the substrate 1 through a liquid pool 9 formed at the point of contact with the lower surface of the substrate 1. , shows how a coating film 7 of a predetermined thickness is formed by simultaneously performing measured scraping (by the action of the bar 2).

In the present invention, in order to uniformly apply the coating, it is important to bring the substrate 1 and the bar 2 into close contact over the entire width. In the case of the method shown in FIG. 1, a system is shown in which the substrate 1 is transported by a bath roll 14 and a pressure roll 15. In this method, it is desirable to use an edge roll as the bus roll 14 so as to avoid contact with the lower surface of the substrate 1 as much as possible. It is preferable to use a pressure roll 15 having an elastic material such as rubber on its surface in order to bring the substrate 1 into close contact with the step/<-16 over the entire width.

In the present invention, as shown in FIG. 3, a bar is used in which the bar diameter at both ends of the bar is smaller than that at the center. By doing this, the width of the coated surface of the coater is narrower than the width of the support. In the present invention, as long as uncoated parts are formed at both ends of the bar, the difference in bar diameter between both ends of the bar and the center can be made arbitrary.1.
It is preferable to make it thinner than 5 mm.

In the present invention, such a coating bar is used and an air blowing nozzle is used to improve the coating thick film portions formed at both widthwise ends of the support.

This aspect will be explained in detail with reference to FIG.

In FIG. 4, the wind blown from the nozzle 21 is blown toward the contact portion between the bar and the support at the end face of the bar.

The air blowing action in the present invention is: (1) suppressing the liquid in the primary side liquid pool from spreading to one end of the bar, (2) holding back the liquid that overflows from the one end of the primary side, and (2) suppressing the liquid that has overflowed from the one end of the primary side. There are three ways to do so: not bypass it to the next side, and let it escape toward one end of the bar. The effect of the embodiment shown in Fig. 4 is ■■. In particular, in order to enhance the effect of It is also better to tilt it somewhat from the secondary side towards the primary side. The angle of inclination is preferably 0 to 60 degrees, preferably 15 to 45 degrees. Also, the smaller the blowing nozzle, the better, with an inner diameter of 2 mm or less, preferably 1 mm.
It is better to be within The tip of the nozzle should be as close to the end surface of the bar as possible without the coating liquid adhering to the nozzle, and in practice it should be 1.5 to 20 mm, preferably 2 to 10 mm. These (small inner diameter and nozzle position) are preferable because they effectively bring out the effect of the wind with a small air volume and do not spread the wind and cause liquid scattering or disturbance of the coated surface. Although the wind speed needs to be appropriately adjusted depending on the coating conditions (coating liquid viscosity, coating speed, etc.), it is preferably in the range of 5 to 30 m/sec. It is of course possible to use a pipe as the blowhole nozzle in the present invention, but in order to improve operability and position setting reproducibility, a block 22 with an air hole bored inside as shown in FIG. It is desirable to be able to set it at a predetermined position with good reproducibility. In order to enhance the effects of the present invention, it is desirable that the end face of the bar has a substantially concentric depression. This is to make it easier for the liquid blown by the wind to escape to the end face of the bar (that is, to enhance the effect of action (2)). With this method, there is no need for the nozzle to become clogged (because no liquid passes through the nozzle), and there is no need for the air outlet to be in close contact with the end surface of the bar, giving you greater flexibility in installing the nozzle. There is.

FIG. 6 shows another embodiment of the invention. In the figure, the end of the bar is provided with a blade 23 that contacts the entire surface of the bar as disclosed in Japanese Patent Application Laid-Open No. 60-225669. 15
The groove of the wire is flattened over a length of mm). This increases the effect of scraping liquid off the bar surface with the blade,
It works to suppress the formation of liquid pools on the primary side of the bar.

Methods of crushing the wire groove include filling the groove with solder, making the rod diameter of a predetermined part twice the wire diameter larger than the rod diameter of the wire-wrapped part, and using a wire bar instead. Plowing can be done using a known method, such as using a grooving bar and not cutting the grooving in a predetermined portion.

In the embodiment according to the invention shown in FIG. 6, a nozzle 21 is further installed at the end of the bar to blow air towards the contact between the bar and the support. In this figure, when there is no wind blowing, the part where the blade is installed at one end of the bar has no primary liquid pool immediately after the coating of the support starts, and becomes very thin or no coating is applied at all, but after a while, the central part of the bar 1 The coating liquid from the liquid pool on the next side pushes up to one end of the bar due to capillary action, and eventually the liquid wraps around the one end of the bar, causing thick coating. The effect of the wind in this figure is the effect of preventing the liquid in the primary liquid pool in the center of the bar from spreading to one end of the bar, and corresponds to the effect (2) described above. In order to increase the effect of the wind in this method, it is thought that it is better for the wind to blow from the outside to the inside, but in reality, blowing in that direction disturbs the liquid in the primary liquid pool. It was found that this tends to cause disturbances on the coated surface. Therefore, it is preferable for the wind direction to be slightly outward rather than perpendicular to the bar. Specifically 10° to 70°, more specifically 30°
°~60° is desirable. Further, as in FIG. 4, the blowing nozzle is preferably thinner, with an inner diameter of 2 mm or less, preferably 1 mm or less. Similarly, the position of the tip of the nozzle should be as close as possible to the end surface of the bar without the coating liquid adhering to the nozzle; in practice, it should be 1 to 10 mm, preferably 1.5 to 5 m.
m is good.

As in FIG. 4, the wind speed also needs to be appropriately adjusted depending on the coating conditions, but is preferably in the range of 5 to 30 m/sec.

The material of the bar 2 used in the present invention is often preferably metal (particularly stainless steel 8) in terms of strength and chemical resistance, but is not limited thereto, and may be a wire bar wrapped with plastic fiber such as nylon, Grooved bars made of rubber or plastic are also used.

As the wire bar, it is also possible to use a lapping bar in which the outer circumferential surface of a wound wire is polished flat to increase the contact area with the substrate processing.

The diameter of the bar 2 is preferably in the range of 6.0 to 30.0 mm, more preferably 6.0 to 20.0 mm; if it is larger than this, it is likely to cause vertical streak-like unevenness in the coating film, and if it is smaller than this, it will be difficult to make it. becomes difficult.

When the bar 2 is a wire bar, in order to obtain a good coated surface, the wire diameter preferably ranges from 0 to C15.
The thickness is preferably 1.0 mm, more preferably in the range of 0.05 to 0.7 mm.

By selecting the bar shape based on these findings, the wet coating volume can be reduced from a thin layer coating of 4 cc/m' to approximately 70 cc/m'.
Stable coating is possible up to a thickness of about m2.

The web or substrate coated in the present invention is not particularly limited, and examples thereof include paper, plastic film, resin coated paper, metal plate, glass plate, etc., and the thickness is also not limited, but is about 0.1 to 10 mm. are preferably used.

The size of the substrate 1 in the present invention is not particularly limited. Generally, in the case of glass substrates, the surface flatness tends to deteriorate as the size increases, but by using a pressure roll 15 with an elastic material on the surface shown in FIG. ) It has been confirmed that the coating can be applied sufficiently evenly to a rectangular glass plate. Note that the substrate 1 can be well coated with either a rectangular or circular shape, and the shape is not particularly limited.

The method of the present invention allows a variety of liquids to be applied to continuous or discontinuous substrates. Although the composition and physical properties of the coating liquid are not particularly limited, those with a viscosity of 100 cpJU or less, particularly 50 cp or less, are suitably applied.

Color filters can be suitably manufactured by the method of the present invention. Normally, when handling color images in an imaging device or display device, the wavelength of visible light is usually divided and extracted, photoelectrically converted, and the electrical energy is converted into light through the steps of amplification, transportation, and amplification. A method of returning to colored light and assembling and displaying colored light is being used. In general, each pixel, which is the smallest unit representing image density, is colored B (blue).
The wavelengths are divided into three wavelengths: , G (edge), and R (red). Imaging devices that do not emit light themselves and display devices such as LCD TVs require filters for this purpose, and these are called color filters. There is.

Pigment-colored photosensitive compositions used in the production of color filters are disclosed in U.S. Pat. No. 3,549.36.
A photopolymerizable photosensitive composition comprising an addition-polymerizable unsaturated monomer, a photopolymerization initiator, and a binder, and a polymer having an unsaturated double bond residue in the main chain or side chain disclosed in Specification No. 7 etc. Photocrosslinkable photopolymers are useful.

Addition polymerizable unsaturated polymer in the photopolymerizable photosensitive composition
is a compound having at least one addition-polymerizable ethylenically unsaturated group and a boiling point of 100° C. or higher at normal pressure.

For example, monofunctional acrylates and methacrylates such as polyethylene glycol mono (meth)acrylate, polypropylene glycol mono (meth)acrylate, phenoxyethyl (meth)acrylate; polyprolene glycol di(meth)acrylate, trimethylolethane tri(meth)acrylate, etc. ) acrylate, neobentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, hexanediol(meth)acrylate, melimethylolpropane tri( Acryloyloxypropyl) ether, tri(acryloyloxyethyl)in cyanurate, polyfunctional alcohols such as glycerin and trimethylolethane added with ethylene oxide or propylene oxide and then converted into (meth)acrylates, Japanese Patent Publication No. 4841708 ,
Urethane acrylates as described in Japanese Patent Publication No. 50-6034 and Japanese Patent Application Laid-Open No. 51-37193,
Polyester acrylates, epoxy acrylates which are reaction products of epoxy resin and (meth)acrylic acid, etc., which are described in JP-A No. 48-64183, JP-B No. 49-43191, and JP-B No. 5230490, etc. Functional acrylates and methacrylates can be mentioned. Furthermore, Japan Adhesive Association Journal Vow, 20, Nn
7. Those introduced as photocurable monomers and oligomers on pages 300 to 308 can also be used. The amount used is
5 to 50 wt% (hereinafter abbreviated as %), preferably 10
~40%.

As a photopolymerization initiator, U.S. Patent No. 2.367, 660
Vicinal polyketaldonyl compounds disclosed in U.S. Pat.
．． 367.670, the acilloin ethers disclosed in U.S. Pat. No. 2,448.828, U.S. Pat. No. 2,72
α-hydrocarbon substituted aromatic acyloin compounds disclosed in US Pat. No. 2.512, U.S. Patent No. 3.04
6.127 and 2.951.758, U.S. Pat. No. 3.549
．． Combination of triallylimidazole dimer/p-aminophenyl ketone disclosed in No. 367, benzothiazole compound/trihalomethyl-S-triazine compound disclosed in Japanese Patent Publication No. 51-48516, patent application Photosensitive 5-)IJ azine compound described in Publication No. 186238/1986, U.S. Patent No. 4,
Trihalomethyl=S-)riazine compounds disclosed in US Pat. No. 239,850, US Pat. No. 4,212.
Examples include the oxadiazole compounds described in No. 976. The amount used is approximately 0.2 to 20 in solid content ratio.
%, preferably 0.5-15%.

The binder is preferably a linear organic polymer that is compatible with the monomer, is soluble in an organic solvent, and can be developed with a weak alkaline aqueous solution. Examples of such linear organic polymers include polymers having carboxylic acid in the side chain, such as JP-A-59-44615 and JP-B-Sho 54-3.
No. 4327, Special Publication No. 12577, Special Publication No. 1977-
No. 25957, JP-A No. 59-53836, JP-A-Sho 5
Methacrylic acid copolymers, acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid as described in No. 9-71048 There are copolymers, etc., and similarly there are acidic cellulose derivatives having carboxylic acid in the side chain. In addition, polymers having hydroxyl groups to which acid anhydrides are added are also useful. Among these, benzyl (meth)acrylate/(meth)acrylic acid copolymers, benzyl (meth)acrylate/(meth)acrylic acid/and multicomponent copolymers with other polymers are particularly preferred.

Other useful water-soluble polymers include polyvinyl pyrrolidone, polyethylene oxide, and polyvinyl alcohol. Alcohol-soluble nylon and polyether of 2,2-bis-(4-hydroxyphenyl)-furopane and epichlorohydrin are also useful in order to increase the strength of the cured film. These polymers can be mixed in any amount, but if it exceeds 90%, it will not give favorable results in terms of the strength of the image formed.

Preferably it is 30-85%.

In addition to the above, it is preferable to further add a thermal polymerization inhibitor, such as hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzogynon, .4'
-thiobis(3-methyl 6-t-butylphenol),
2.2'-methylenebis(4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, and the like are useful.

A suitable amount of thermal polymerization inhibitor is usually added to the commercially available Sentsumar.

As a photocrosslinkable photopolymer, for example, JP-A-51
- the polyester compound disclosed in No. 96696,
British Patent No. 1.112.277, British Patent No. 1.313.3
No. 90, No. 1.341.004, No. 1,377.
They include polyvinyl cinnamate-based photosensitive polymers described in specifications such as No. 747 and JP-A No. 55-23941.

Useful organic solvents for the photosensitive composition include glycol ether-based methyl cellosolve, ethyl cellosolve, propyl cellosolve, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether and their acetates, i.e., methyl cellosolve acetate; Ethyl cellosolve acetate, propyl cellosolve acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol probyl ether acetate are useful. Acetate esters include amyl acetate, butyl acetate, propyl acetate, and ethyl acetate, and ketones include methyl isobutyl ketone, methyl ethyl ketone,
Acetone, cyclohexanone, dimethylformamide, dimethylsulfoxide, methylpyrrolidone, T-butyrolactone, ethyl lactate, and the like are useful, and each alkyl group may be a linear or branched isomer.

The solution concentration can range from 3% to 70%, with a more preferred range being 15% to 50%.

The coloring materials include, for example, azo, anthraquinone, xanthine, quinacridone, indigo, dioxazine, indanthrone, isoindolinone, phthalocyanine, triphenylmethane, nitroso, perylene, Isoindoline pigments are useful, e.g.
Phthalocyanine blue (C, I, pigment blue 15
:6 or C, I, Pigment Blue 15:3: For example, Lionor Blue ES manufactured by Toyo Ink Manufacturing ■, Chromo Blue A3R manufactured by Ciba Geigy Co., Ltd.), Phthalocyanine Green (C, I. Pigment Green 7.36, or [ , 1. Pigment Green 37: For example, Lionol Green 2YS manufactured by Toyo Ink Manufacturing ■), perylene pigment (c, 1. Pigment Red 155, anthraquinone U material (C, I, Pigment Red 177: for example,
Lionogen Red GD (manufactured by Toyo Ink Mfg. ■, Chromophthal Red BRN (manufactured by Ciba Geigy)) are useful, and C1I and Pigment Yellow 83 are also useful for color correction.
, C61, Pigment Ero-154: For example, Glue Onogen Yellow 30SC, 1, manufactured by Toyo Ink Manufacturing ■, Pigment Violet 23: For example, Glue Onogen Violet) RL, manufactured by Toyo Ink Manufacturing ■, etc. are particularly preferred. The coloring material is dispersed in the photocurable photosensitive composition to produce a colored photosensitive composition.

The proportion of the pigment in the photosensitive layer is 5 to 90 in terms of solid content.
%, more preferably 10 to 60%.

〔Effect of the invention〕

According to the coating method of the present invention, it is possible to reduce the thickness of the thick coated film portions that occur at both ends in the width direction of the support, and to make the thickness of the coated film uniform. Therefore, according to the method of the present invention, coated webs or substrates can be produced very efficiently.

Therefore, the present invention can efficiently produce photosensitive materials such as photographic film and photographic paper, photolithographic materials, magnetic recording materials such as magnetic recording tape, pressure-sensitive recording paper, heat-sensitive recording paper, and the like. In addition, when coating semiconductor wafers or photoresists for photomasks used in their manufacturing, solder resist coating for printed circuit boards, glass substrate coating, etc., it is possible to uniformly coat large-sized substrates or substrates of arbitrary shapes. Furthermore, an economically superior coating method with less loss of coating liquid is provided.

Further, when the method of the present invention is applied to a method for manufacturing a color filter, a solution of a colored photosensitive composition can be evenly applied over a large area.

Therefore, by the method of the present invention, liquid crystal color displays, liquid crystal color televisions, color image pickup tubes, color image sensors, etc. can be manufactured easily and at low cost.

Next, the present invention will be explained with reference to Examples.

〔Example〕

Example 1 Using the bar coating device shown in FIG.
A photoresist solution was applied onto a glass substrate of 45 cm and a thickness of 1.1 mm. The bar 2 was made of 12I [1I11 diameter stainless steel wire wrapped with 0.175 mm diameter stainless steel wire, and the end face was provided with concentric depressions at an angle of 45° as shown in FIG. In addition, the height of the steps was set to 2. The conveyance speed of the substrate and the rotation speed of the wire bar were both 3 m/min.

At this time, as shown in FIG. 4, air was blown from a nozzle toward the contact area between the bar and the glass plate at one end surface of the bar.

The blowing nozzle was a pipe with an inner diameter of 0.9 m, the blowing direction was inclined at 45° from the secondary side toward the primary side, and the tip of the nozzle was set to be approximately 5 l apart from the end surface of the bar. The air volume was set so that the wind speed was 15 m/sec at the nozzle exit. Thick coating occurred at both widthwise ends of the coated surface as shown in Figure 8, but the maximum film thickness at the coating edge was about 3 times the average film thickness a at the center, and within 5% of the average film thickness. The distance n1 to enter the ball has been improved to about 10 fights.

Example 2 Using a bar with a wire groove crushed with solder to the width of the edge part 5, as shown in Figure 6, while touching the blade over 10 parts of the edge part, the bar and the glass plate were connected at the end of the bar. Air was blown from a nozzle toward the contact area. The blowing nozzle was a vibrator with an inner diameter of 0.9 mm, the blowing direction was 45° outward, and the tip of the nozzle was set to be approximately 2.5 mm away from the bar surface. The air volume was set so that the wind speed was 15 m/sec at the nozzle exit. Note that the other conditions are the same as in Example 1. As a result of coating in this manner, thick coating as shown in Fig. 8 occurred at both ends of the coated surface in the width direction, but the maximum film thickness at the coating edge portion was approximately equal to the average film thickness a at the center. twice,
The distance 1 to be within 5% of the average film thickness is approximately 5m+n
and improved.

Comparative Example 1 As shown in Figure 7, coating was carried out in the same manner as in Example 1, except that no measures were taken at the edges. Thick coating as shown occurred, and the maximum film thickness at the coating edge portion was about 5 times the average film thickness a at the center, and the distance 1 required to be within 5% of the average film thickness was about 25 mm.

Comparative Example 2 Using a bar with a wire groove crushed with solder with a width of 5 mm at the edge part, as shown in Fig. 9, the bar edge part was 10 m wide.
Coating was carried out in the same manner as in Example 1, except that the blade was brought into contact with the blade over a distance of approximately 30 mm. Due to the effect of the blade to scrape off liquid on the bar surface, there was a thick layer on both ends of the coated surface in the width direction from the tip of the substrate for approximately 30 mm. No coating occurs, but after that, a thick coating gradually occurs until 50m from the tip of the board.
After m, the maximum film thickness at the coating edge portion was about 4 times the center average film thickness a, and the distance 1 required to be within 5% of the average film thickness was about 15 mm.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the bar coating method of the present invention, and Fig. 2 is a schematic diagram of the bar coating method of the present invention.
FIG. 3 is a perspective view of the stepped bar, and No. 4 rl! J is a sectional view of another form of stepped bar, FIGS. 5 and 6 are schematic diagrams showing the coating method of the present invention,
7 and 9 are diagrams showing comparative coating methods, and FIG. 8 is a diagram showing the film thickness distribution formed by coating. 1... Board, 2... Bar 3...
Coating liquid, 4...Liquid supply hole, 5...Weir member, 6...Bar support member, 7...Coating film, 8...Liquid storage part, 9... -Liquid pool, 10...Bar coating device, 14...Bath roll, 15...Press roll, 16...Stepped bar 21...Wind blowing nozzle, 22...・Wind blow block, 23...Blade. Figure 4 Figure 6 Figure 7 Figure 9 Figure 5 (A) (B) Figure 8 (A) Procedural amendment (method) 3. Person making the amendment Relationship to the case Applicant name Fuji Photo Film Co., Ltd. Company 4, Agent 5, Date of amendment order: October 30, 1990

Claims (3)

[Claims] (1) Bar coating in which a coating liquid is supplied so that a liquid pool is formed just before the contact part of a support that is traveling while being in contact with a rotating bar, and the coating liquid is applied to the support using the bar. In the method, by making the bar diameter at both ends of the bar smaller than that at the center part, uncoated parts are provided on both sides of the support, and at the ends of the contact part between the bar and the support in the application part. A bar application method characterized by blowing with wind. (2) At both ends of the effective application width of the application bar, a blade is provided that contacts a part of the surface of the bar, so that the amount of liquid accumulated just before the contact area between the bar and the support at both ends is lower than that at the center. The bar coating method according to claim 1, characterized in that the bar coating method comprises: (3) The bar coating method according to claim 1, wherein both end surfaces of the coating bar have substantially concentric depressions.