JP2004016877A - Method and apparatus for curtain coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for a curtain coating for stably and continuously carrying out uniform coating without coating the end part the web side. <P>SOLUTION: A coating solution is applied to a web 10 transported by a back-up roll 11 by the curtain coating. An ear folding member 20 and an ear folding auxiliary member 21 are set in the position in the range of 2 mm to 40 mm on the upstream side from the coating starting line L1 and in which the web 10 is wrapped with the back-up roll 11 and the side end part of the web 10 is folded in the opposed direction to the face to be coated. The surface of the ear folding member 20 and the ear holding auxiliary member 21 is ceramic and the gap CL1 between both members is adjusted to satisfy 0.5 mm ≤ CL1 ≤ 5.0 mm and the ear folding width W is adjusted to satisfy 2CL1 ≤ W ≤ 10CL1. The shape of the ear folding member 20 in the web transporting-in side and the shape of the ear foling auxiliary member 21 in the web supporting side are made to be curvature shapes. A uniform coat film 12c without coating the side end part can be formed and coating can continously and stably be carried out. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for curtain coating various liquid compositions on a continuously running support (web), and in particular, pressure-sensitive recording paper, thermal recording paper, inkjet recording paper photographic film, and photographic printing paper. The present invention relates to a curtain coating method and apparatus having continuous coating stability which are preferably used for the above-mentioned.
[0002]
[Prior art]
There is a curtain coating method as one of the methods of coating a coating solution on a continuously running web by single layer coating or multilayer coating. The curtain coating method is a method of forming a coating film by allowing a coating liquid to freely fall in a curtain shape and colliding with a web traveling while being supported by a backup roll or the like. Curtain coating is relatively easy to increase in coating speed compared to other coating methods, and multi-layer simultaneous coating is possible, so that its technical application is expanding.
[0003]
In curtain coating, both side edges in the width direction of the curtain to be formed are normally held by two edge guides, thereby stabilizing the curtain. However, according to the method using this edge guide, when the entire curtain is coated on the web, there has been a problem that the film thickness at both side edges of the coating film becomes thicker than the other parts.
[0004]
The thick coating phenomenon induces various harmful effects in industrial production. In particular, the thick coating part is one of the main factors that increase the production cost because the energy required for drying and the time required for drying are longer than other parts. In addition, if it is transferred to the subsequent process without being sufficiently dried, the coating solution may be transferred to the process equipment such as a transport roller and contaminated, or may be adhered by winding with a winding roll. In other words, the web may be cut during unwinding from the roll.
[0005]
Even when the above problems related to drying are solved, there is another problem. When this is wound on a take-up roll, the overlapping portion of both end portions of the web, which is a thick coating portion, becomes convex and may be cut to make long winding difficult. Moreover, since the film side edge part which is a thick coating part is cut and removed later, the energy in the drying process spent on the thick coating part can be regarded as a production loss as it is.
[0006]
Thickness of the coating film formed on the support by making the width of the curtain film larger than the width of the support to be equal to or greater than the width corresponding to the thick coating as a method of preventing thick coating on both side edges. A method for making the thickness uniform is widely known. In this case, the curtain film outside the side edge of the support falls without being applied, is collected in a container or the like installed in advance, and is reused as the application liquid. Similarly, in the case where the coating film is formed in multiple layers, a method for applying the curtain film with a wider width than that of the support is disclosed in JP-A-50-88138, JP-A-54-124039, and the like. Proposed by and generally known.
[0007]
However, according to this method, since the coating liquid is applied to the entire surface of the support, that is, the range reaching both side edges, the undried coating liquid adheres to and contaminates the roll or belt that conveys the support. The problem remains. Also, in the case of pressure-sensitive copying recording paper and thermal recording paper using paper as a support, both ends curl on the anti-coating surface by applying the coating liquid, and both ends of the coating surface are moved until the drying process is started. There is also a phenomenon that the coating liquid of the part contaminates the equipment in process. This phenomenon may also be seen in the drying process. Japanese Patent Laid-Open No. 54-25066 proposes a floater dryer that transports a support without contact and simultaneously performs drying. However, in this case as well, there remains a problem that the support is fluttered.
[0008]
The above-mentioned problem of process contamination due to the coating liquid leads to the cause of product defects. To solve this problem, the side edge of the support is folded to the anti-coating surface side by bending means, and this edge is not coated. A curtain coating method for preventing process contamination is proposed in Japanese Patent Publication No. 2-1550.
[0009]
[Problems to be solved by the invention]
However, according to the method disclosed in Japanese Patent Publication No. 2-15550, although process contamination is eliminated, another problem may occur. In other words, pressing the edge folding member against the end of the running support causes the support to float and vibrate, causing coating unevenness, or returning to the original folding of the ear at the application start position, Is applied, or the joint portion of the web is caught by the ear fold member and the web is broken. In addition, when the coating amount of the coating liquid is particularly large, both ends of the coating film are thickly coated, and as a result, when winding with the winding roll, the overlapping portion of the end becomes convex, and winding is impossible. Sometimes.
[0010]
This invention is made | formed in view of the said subject, and it aims at providing the curtain coating method and apparatus for suppressing the thick coating of a side edge part and performing a continuous coating stably.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the curtain coating method of the present invention is a method in which a coating liquid is collided by free fall on a support that is continuously supported by a backup roll, and the support is supported by a bending means. In the curtain coating method in which the both ends of the body are folded in the direction of the anti-coating surface and the coating liquid is applied, when the distance from the bending position to the coating start position is D, 2 mm ≦ D ≦ 40 mm It is structured as a feature.
[0012]
The backup roll has a width smaller than that of the support, and bending and coating are performed in a winding section of the support by the backup roll. Regarding the cross-sectional shape parallel to the support surface of the bending means, the upstream side of the backup roll facing side may be an arcuate curved shape, and further, a linear shape of 5 mm or more may be provided in the support running direction of the portion in contact with the support. preferable. As for the surface material of the bending means, it is preferable that at least a portion in contact with the support is ceramic.
[0013]
A folding auxiliary means is installed at a position close to or in contact with both end portions of the backup roll so as to face the folding means, and the bending means has a shape perpendicular to the advancing direction of the support of the folding auxiliary means. The opposite side is an arcuate curved shape or a polygonal shape. This folding assisting means is 0.5 mm ≦ CL1 ≦ 5 when the surface material of at least the part in contact with the support is ceramic, the clearance with the bending means is CL1, and the bending width of the support is W. 0.0 mm and 2CL1 ≦ W ≦ 10CL1.
[0014]
When the bending assisting means is not used, the cross-sectional shape of both end portions of the backup roll is preferably an arcuate curved surface shape or a polygonal shape, and the surface material is preferably ceramic. The side end portion of the backup roll and the bending means It is desirable to set so that 0.5 mm ≦ CL2 ≦ 5.0 mm and 2CL2 ≦ W ≦ 10CL2 where CL2 is CL2 and the bending width of the support is W.
[0015]
When the support is bonded to each other in the longitudinal direction by a bonding tape, it is preferable to temporarily stop the folding function of the bending means when the joint passes through the bending means. .
[0016]
Further, the curtain coating apparatus of the present invention is an apparatus for applying the coating liquid by colliding with a free fall onto a support that is continuously supported by a backup roll, and the both ends of the support are covered by a bending means. In a curtain coating apparatus that folds in the direction of the anti-coating surface and applies the coating liquid, where D is the distance from the folding position to the coating start position, 2 mm ≦ D ≦ 40 mm and a width smaller than that of the support. Using the backup roll, the bending and the coating are performed in the winding section of the support by the backup roll.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a curtain coating process embodying the present invention. The web 10 as a support is continuously conveyed while being supported by the backup roll 11. The coating liquid 12a applied to the web 10 is supplied from a coating liquid tank (not shown) to the manifold 14 of the coating die 13 by a liquid feeding pump (not shown) having a variable feeding amount. The manifold 14 is formed with its cross-sectional shape in the width direction of the coating die 13. The supply of the coating liquid 12 a may be performed from the center in the width direction of the manifold 14 or may be performed from one side surface of the manifold 14.
[0018]
Both ends of the curtain film 12b formed by free fall are held by edge guides (not shown), and the coating die 13 is installed so that the height of the curtain film 12b is 30 mm or more and 300 mm or less. The curtain film 12b collides with the traveling web 10 and forms the coating film 12c on the downstream side of the coating start line L1. The position of the coating die 13 is adjusted so that the coating start line L1 is within the range wrapped by the backup roll 12 of the web 10. At both ends of the web 10, an ear fold member 20 is installed as a folding means at an upstream position of the application start line L 1, and the ear fold portion 10 a is temporarily formed by bending. Due to the shape restoration characteristics of the web 10, the bending of the ear fold 10 a is gradually eliminated after the coating process, and almost no folding mark is left as indicated by L <b> 2.
[0019]
FIG. 2 is a perspective view of the coating process in the curtain coating method of the present invention. Note that the edge guide is not shown. Let D be the distance from the application start line L1 to the place where the ear fold is performed in the ear fold member 20, that is, the place where the web is away from the ear fold member 20. The installation position of the ear folding member 20 is in a range where 2 mm ≦ D ≦ 40 mm is satisfied and the web 10 is wrapped by the backup roll 11. Further, an ear folding assisting member 21 as a folding assisting unit is installed facing the ear folding member 20. The backup roll 11 has a smaller width than the web 10, the web 10 is folded to the anti-coating surface side by the ear fold member 20, and the folded ear fold 10 a is between the web support surface of the backup roll 11. It is applied while being transported on the backup roll 11 so as not to be pinched. The coating liquid 12a is naturally dropped from the coating die 13 (see FIG. 1) so as to form a curtain film 12b having a width larger than the width of the web 10, and the coating liquid 12a is applied to the end portion of the folded web ear fold 10a. Do not apply.
[0020]
3 and 4 show an ear folding process in which the present invention is implemented, and both show only the vicinity of one side of the backup roll 11. FIG. 3 is a plan view from above, with the web 10 omitted. FIG. 4 is a cross-sectional view of the web 10 as seen from the traveling direction side. The ear fold auxiliary member 21 is installed in the vicinity of the backup roll 11 by a fixing member (not shown), and the ear fold member 20 is further installed on the outside thereof. The ear fold portion 10a (see FIG. 1) bent along the ear fold line L2 travels through the gap between the ear fold member 20 and the ear fold auxiliary member 21.
[0021]
In the case where the web 10 is folded using the ear fold member, the liquid residue may solidify after the coating liquid 12a contaminates the ear fold member 20. In many cases, the web 10 is caught by this solidified material and breaks. According to the above-described method of the present invention, it is possible to prevent the occurrence of such a phenomenon and stably continue the application excluding the ear fold 10a. The curtain film 12b that protrudes from both ends of the web 10 is collected and reused as the coating liquid 12a. Further, since the ear fold is performed within the range wrapped by the backup roll 11, it is possible to prevent the web fold portion 10a from being lifted, which tends to occur during the ear fold.
[0022]
Further, the gap CL1 between the ear fold member 20 and the ear fold auxiliary member 21 is set to 0.5 mm or more and 5.0 mm or less, and the ear fold width W of the web is set to be 2 times or more and 10 times or less of the gap CL1. preferable. Even if the gap CL1 is set within the above range, if the ear fold width W is larger than 10 times the gap CL1, the thick coating of the coating film 12c tends to occur at the ear fold line L2 and its vicinity. More preferably, the gap CL1 is 0.5 mm or more and 2.0 mm or less, and the ear fold width W of the web 10 is 3 times or more and 5 times or less of the gap CL1. In addition, the ear fold member 20 may be parallel to the web folding direction with respect to the ear fold auxiliary member 21, and may be parallel to the web traveling direction side, or may be inclined when viewed from the web traveling direction side. Also good. In the case of being inclined, the gap between the web and the ear folding assisting member 21 at the position where the web is in contact with the ear folding member 20 is CL1.
[0023]
By the way, application | coating can be continuously implemented by joining the terminal part and the starting-end part of each of the web 10 wound by the different roll. As a joining method, both end portions are often overlapped and joined using a double-sided tape or the like.
[0024]
If the gap CL1 between the ear fold member 20 and the ear fold auxiliary member 21 is small, the web 10 may be caught. This is particularly a concern at the joints of the web 10. Since the hook of the web 10 on the ear fold member 20 leads to deformation and breakage of the web 10, it is necessary to consider the installation of the ear fold member 20. In the coating method and apparatus of the present invention, the ear folding member 20 can be attached at any angle. That is, when a portion where the thickness of the web is extremely thick as compared with the steady portion or a portion having a step at the end passes through the ear fold member 20 like the above-described joint portion, as shown by a wavy line in FIG. Then, the ear folding member 20 is tilted outward to stop the function as the ear folding member, and after the joint has passed, it can be returned to the original position and the ear folding can be performed again. The ear folding member 20 is not limited to this installation method, and the entire ear folding member 20 may be moved outward by an air cylinder or the like.
[0025]
In the coating method and apparatus of the present invention, as the ear fold member 20, a curved surface portion 20a is provided at the upstream portion of the surface facing the backup roll 11 and the ear fold auxiliary member 21, as shown in FIG. In this case, a portion provided with a straight portion in the web traveling direction is used as a portion where the bent web 10a contacts. When the length of the straight portion in the web running direction is L20, L20 is set to 5 mm or more.
[0026]
Further, the surface of the ear fold auxiliary member 21 that supports the web 10 is an arc that is the same as the outer peripheral surface of the backup roll 11, and a curved surface is formed at the side end portion below the ear fold line L 2 as shown in FIG. A shape portion 21a is provided. By using this ear fold auxiliary member 21, it is possible to prevent thick coating of the coating film 12c in the vicinity of the edge of the coating film after the ear folding, that is, in the vicinity of the ear folding line L2, which occurs in the case of a vertical square shape.
[0027]
FIG. 5 is a plan view of the vicinity of the ear folding member as seen from above. (A) has shown the ear fold member 2 as other embodiment of this invention, and makes the upstream part of the surface facing the ear fold auxiliary member 21 into the square shape 2a. In the case of a square shape, this may damage the web 10 and later cause breakage. On the other hand, (B) shows an ear-folded member 3 as still another embodiment of the present invention, and has a cylindrical shape with a circular cross section. In this case, the occurrence of the scratch can be suppressed, but there is a problem that the flat state is restored even when the ear folding is incomplete. In the present invention, by using the ear folding member 20 having the shape shown in FIG. 3, the ear folding portion 10 a of the web is smoothly bent by the ear folding member 20 and conveyed between the ear folding assisting member 21. Can do a full ear fold.
[0028]
FIG. 6 shows an ear fold auxiliary member 25 which is another embodiment of the present invention, and is a cross-sectional view seen from the upstream side. The curved surface shape portion at the side end portion shown in FIG. 4 is a polygonal shape portion 25a. This shape also has the effect of preventing thick coating of the coating film 12c in the vicinity of the ear fold line.
[0029]
In the present invention, as the ear fold member 20 and the ear fold auxiliary members 21 and 25, those whose surface material is ceramic are used, and wear due to long-term contact with various webs can be prevented. The ceramic may be at least a portion where the web 10 may come into contact, or the member itself may be made of ceramic. Ceramics include oxide ceramics, carbide ceramics, nitride ceramics, boride ceramics, siliconized ceramics, sulfide ceramics, etc., depending on the type, hardness, surface condition, etc. of the web 10 used. Can be selected as appropriate.
[0030]
A backup roll having the functions of the ear fold auxiliary members 21 and 25 may be used without using the ear fold auxiliary members 21 and 25. In FIG. 7, the principal part of the ear folding process as other embodiment of this invention is shown. The backup roll 30 has the functions of the backup roll 11 and the ear fold auxiliary members 21 and 25 described above. That is, the function of conveying the web 10 while supporting it, the function of forming a suitable ear fold 10a in the implementation of the ear fold by the ear fold member 20, and the function of preventing thick coating of the coating film 12c in the vicinity of the ear fold line L2. It is. As shown in FIG. 7, the cross-sectional shape of the side end portion has an arc fold member side as an arc curve 30 a, but may have a polygonal shape like the ear fold assist member in FIG. 6. In this case as well, the ear folding member 20 may be parallel to the backup roller 30 in the web running direction, and may be parallel to the web traveling direction side, or may be inclined as viewed from the web traveling direction side. May be. In the case of being inclined, the gap between the web and the backup roll 30 at the position where the web is in contact with the ear folding member 20 is CL2.
[0031]
A pressure reducing chamber (not shown) may be provided on the upstream side of the coating process to reduce the pressure. In curtain coating, there is concern about the generation of an air entrained flow as the coating speed increases, and the effect of the air entrained flow on the curtain film 12b can be reduced by the above-described decompression process. Furthermore, the effect can be further improved by providing a wind shielding device in the vicinity of or in contact with the web 10 on the most upstream side of the decompression chamber.
[0032]
As the backup roll 11, it is preferable to use a roll having a radius of curvature of 100 mm or more around the web 10. In a thin backup roll having a radius of less than 100 mm, the wrap length with respect to the web 10 is shortened, or the angle formed by the web 10 and the curtain film 12b is merely shifted slightly from the position of the coating start line L1 in the web traveling direction. This is because the stable region of application becomes narrow. It is desirable that the outer peripheral surface be as smooth as possible.
[0033]
The degree of reduced pressure during application is usually set higher as the application speed increases. In the case of coating at a relatively low speed of approximately 400 m / min or less, there is little need for depressurization. However, when the coating speed is generally regarded as high-speed coating of 500 m / min or more, it is preferable to depressurize, for example, 500 m / min. The coating speed is preferably 20 Pa or more and 500 Pa or less under a coating speed of min or more and 800 m / min or less. However, in addition to the coating speed, it is necessary to take into consideration the coating flow rate and the wet film thickness of the coating film 12c, and are not limited to the above range. By this method, it is possible to suppress the entrained air flow as described above, and to stabilize the curtain film.
[0034]
In the curtain coating method and apparatus of the present invention, various known webs can be used as the web 10. Generally, paper, various laminated papers coated with or laminated with α-polyolefins having 2 to 10 carbon atoms such as polyethylene (PE), polypropylene (PP), ethylene butene copolymer, and polyethylene terephthalate (PET) , Polyethylene-2,6-naphthalate (PEN), cellulose diacetate (DAC), cellulose triacetate (TAC), cellulose acetate propionate, polyvinyl chloride (PVC), polyvinylidene chloride, polycarbonate (PC), polyimide (PI ), Various known plastic films such as polyamide (PA), metal foils such as aluminum, copper, tin, etc., such as those obtained by forming a preliminary processing layer on the surface of a belt-like substrate, or various composite materials obtained by laminating these layers Is included. Further, the web 10 was coated with an optical compensation sheet coating solution, an antireflection film coating solution, a magnetic coating solution, a photographic photosensitive coating solution, a surface protecting, antistatic or slippery coating solution, and dried. Later, it may be cut into a desired length and width, and representative examples thereof include, but are not limited to, optical compensation sheets and antireflection films.
[0035]
In the coating method and apparatus of the present invention, the coating liquid 12a preferably has a viscosity of 10 to 300 mPa · s and a surface tension of 15 to 50 mN / m during coating. As the solvent for the coating solution 12a, various known solvents such as water, various halogenated hydrocarbons, alcohols, ethers, esters, ketones, and the like can be used alone or in combination.
[0036]
【Example】
EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited to this.
[0037]
[Example 1]
80 g / m ² A high-quality paper was used as the web 10, and a pigment coating solution was curtain-coated on this. The viscosity of the coating liquid 12a at room temperature was 120 mPa · s, and the surface tension was 40 mN / m. The coating die 13 is installed so that the height of the curtain film 12b is 150 mm, the coating start line L1 is at the top of the roll curved surface of the backup roll 11, the web ear fold width W is 10mm, and the wrap angle by the backup roll 11 is set. Was 6 °. The backup roll 11 had a radius of 180 mm, the side end portion did not have a curved surface shape, and was placed close to the ear folding assisting member. As the ear folding member, a member having a curved surface on the upstream side and having a 5 mm straight portion in the web running direction as a web contact surface (see FIG. 3) was used. The edge folding assisting member has a curved shape as shown in FIG. Further, the positions of the ear fold member 20 and the ear fold auxiliary member 21 were set at a location 10 mm upstream from the application start line L 1 and where the web 10 was wrapped by the backup roll 11. The surface material of the ear folding member and the ear folding assisting member was silicon nitride. Application amount is 50 g / m ² The coating speed was set at 600 m / min. The coating film after drying is 15 g / m ² Met. As a result of this example, coating was performed in a very stable and continuous manner, and the obtained coating film 12c was very good with both sides of the web uncoated.
[0038]
[Example 2]
The radius of the backup roll is 200 mm, the wrap angle of the web is 10 °, and the positions of the ear fold member 20 and the ear fold auxiliary member 21 are 25 mm upstream from the coating start line L1 and within the wrap range of the web 10 The other conditions were the same as in Example 1. As a result of this example, coating was performed in a very stable and continuous manner, and the obtained coating film 12c was very good with both sides of the web uncoated.
[0039]
Example 3
The positions of the ear folding member 20 and the ear folding assisting member 21 were 5 mm upstream from the coating start line L1 and within the wrapping range of the web 10, and the other conditions were the same as in Example 1. As a result of this example, coating was performed in a very stable and continuous manner, and the obtained coating film 12c was very good with both sides of the web uncoated.
[0040]
[Comparative Example 1]
The positions of the ear folding member 20 and the ear folding assisting member 21 were 50 mm upstream from the application start line L1, and other conditions were the same as in Example 1. As a result of this comparative example, the ear fold was insufficient, and the coating liquid was applied to the entire width region of the web 10.
[0041]
[Comparative Example 2]
The positions of the ear folding member 20 and the ear folding assisting member 21 were set within the lapping range of 1 mm upstream from the coating start line L1, and other conditions were performed in the same manner as in Example 1. As a result of this comparative example, the curtain film 12b and the ear fold member 20 interfered with each other, the ear fold member was contaminated, and the contaminant was solidified to form a projection. The projection was caught by the web 10 and the web 10 was cut.
[0042]
[Comparative Example 3]
The web wrap angle was set to 0 °, and the other conditions were the same as in Example 1. As a result of this comparative example, both end portions of the web 10 were lifted from the backup roll 11, and stepped unevenness of the coating film was recognized at the portion where the lift occurred.
[0043]
From the results of Examples 1 to 3 and Comparative Example 3 above, the distance D from the folding execution point to the coating start line L1 is 2 mm or more and 40 mm or less, and the bending execution point is within the web wrapping range. It turns out that it is effective for the uniform curtain application | coating which made the both ends of the web uncoated.
[0044]
[Comparative Example 4]
The same operation as in Example 1 was carried out except that an edge folding member 20 having an upstream shape with a vertical corner (see FIG. 5A) was used. As a result of this comparative example, scratches were observed at the end of the web 10, and the site where the cut occurred was also confirmed.
[0045]
[Comparative Example 5]
The same operation as in Example 1 was performed except that a cylindrical member (see FIG. 5B) was used as the ear folding member. As a result of this comparative example, the ear fold was incomplete, and the coating liquid 12a was applied to the entire width region of the web 10.
[0046]
From Example 1 and Comparative Examples 4 and 5, the shape of the ear fold member is such that the upstream side is curved as shown in FIG. 3, and the web contact surface has a straight portion of 5 mm or more in the web running direction. This is effective, and as a result, it can be seen that sufficient ear folding can be performed on the side end portion without scratching the web during the ear folding.
[0047]
Example 4
The ear folding assisting member 21 has a polygonal shape (see FIG. 6) at the side end, and the gap CL between the ear folding member 20 and the ear folding assisting member 21 is 2 mm, and the ear folding width W is 8 mm. The other conditions were the same as in Example 1. As a result of this example, the coating was carried out very stably and continuously, and the obtained coating film 12c was good with both sides of the web not applied.
[0048]
According to the fourth embodiment, as the cross-sectional shape of the side end portion of the ear fold auxiliary member 21, a polygonal shape is also effective, and the gap CL between the ear fold member 20 and the ear fold auxiliary member 21 is 0.5 mm or more and 5 mm or less. It can be seen that it is effective to set the ear fold width W such that 2CL ≦ W ≦ 10CL.
[0049]
【The invention's effect】
As described above, it can be seen that the curtain coating method and apparatus of the present invention can be carried out stably and continuously, and as a result, a good coating film can be obtained.
[Brief description of the drawings]
FIG. 1 is a side view having a partial cross section of a curtain coating process embodying the present invention.
FIG. 2 is a perspective view of the curtain coating process.
FIG. 3 is a plan view showing a positional relationship among a backup roll, an ear fold member, and an ear fold auxiliary member.
4 is a cross-sectional view taken along line IV-IV in FIG.
FIGS. 5A and 5B are plan views corresponding to FIG. 3 of an ear fold member implemented as a comparative example of the present invention.
6 is a cross-sectional view corresponding to the line IV-IV in FIG. 3 of the ear fold member and the ear fold assisting member according to another embodiment of the present invention.
7 is a cross-sectional view corresponding to the line IV-IV in FIG. 3 of a backup roll according to another embodiment of the present invention.
[Explanation of symbols]
10 Web
10a Folding part
11 Backup roll
12a Coating solution
12b Curtain membrane
12c paint film
13 Application die
20 Folding members
20a Curved shape part
L20 Straight part
21 Ear folding aids
21a Curved shape part
25 Earfold assisting member
25a Polygonal shape part
30 Backup roll
30a Curved shape part
CL1 Gap between the ear fold member and the ear fold auxiliary member
CL2 Gap between the backup roll and the folded ear member
D Distance between the ear fold and the application start point
L1 coating start line
L2 Ear fold line
W Ear fold width

Claims (12)

It is a method of applying a coating liquid by colliding with a free fall on a support that is supported by a backup roll, and the both ends of the support are bent in the direction of the anti-coating surface by a bending means. In the curtain coating method to apply,
2. A curtain coating method characterized in that 2 mm ≦ D ≦ 40 mm, where D is the distance from the bending location to the coating start location. In a cross section parallel to the support surface of the bending means,
The curtain coating method according to claim 1, wherein an upstream side of the backup roll facing side has an arcuate curved shape. In a cross section parallel to the support surface of the bending means,
The curtain coating method according to claim 1 or 2, wherein a linear shape in the direction of travel of the support of 5 mm or more is provided at a site where the support contacts. The curtain coating method according to any one of claims 1 to 3, wherein the surface material of at least a portion of the bending means that contacts the support is ceramic. A cross-sectional shape perpendicular to the advancing direction of the support body of the folding auxiliary means is installed at a position close to or in contact with both end portions of the backup roll so as to face the folding means. 5. The curtain coating method according to claim 1, wherein the side opposite to the bending means has an arcuate curved shape or a polygonal shape. 6. The curtain coating method according to claim 5, wherein a surface material of at least a portion of the bending assisting unit that contacts the support is ceramic. When the gap between the bending assisting means and the bending means is CL1, and the bending width of the support is W, 0.5 mm ≦ CL1 ≦ 5.0 mm and 2CL1 ≦ W ≦ 10CL1 The curtain coating method according to claim 5 or 6. 5. The curtain coating method according to claim 1, wherein a cross section of both end portions of the backup roll is an arcuate curved surface shape or a polygonal shape. The curtain coating method according to claim 8, wherein a surface material of both side ends of the backup roll is ceramic. When the gap between the side end portion of the backup roll and the bending means is CL2, and the bending width of the support is W, 0.5 mm ≦ CL2 ≦ 5.0 mm and 2CL2 ≦ W ≦ 10CL2. The curtain coating method according to claim 8 or 9, wherein: The support is formed by joining the supports in a longitudinal direction with a joining tape, and when the joining portion passes the previous folding means, the folding function of the folding means is temporarily stopped. The curtain coating method according to any one of claims 1 to 10. An apparatus for applying a coating solution by colliding with a free fall on a support that is supported by a backup roll, and bending the both ends of the support in the direction of the anti-coating surface by means of bending means. In curtain applicator to apply,
When the distance from the place where the bending is performed to the application start position is D, 2 mm ≦ D ≦ 40 mm, and the backup roll having a smaller width than the support is used to wind the support by the backup roll. A curtain coating apparatus characterized in that the bending and the coating are carried out in an attachment section.

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