JP2017209652A - Roll coating device, and method for manufacturing film-coated web - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict unevenness in film thickness of a coated film in a width direction without transferring a cell pattern onto the coated film, while suppressing manufacturing and maintenance costs, in applying coating to a continuously conveyed web using a coating roll.SOLUTION: A roll coating device includes: coating liquid supply means that supplies coating liquid; a coating roll that has a surface onto which the coating liquid supplied from the coating liquid supply means is adhered, and that rotates in order to transfer the coating liquid over the whole width of one surface of a web; a blade disposed toward the surface of the coating roll; and pressing means that presses the whole width of the other surface of the web at a position where the coating roll contacts the one surface of the web. The coating roll is not provided with a recessed portion for liquid accumulation on its roll surface, and the blade contacts the coating liquid adhered to the surface of the coating roll over a width that is equal to or larger than the width of the web width, without contacting the surface of the coating roll.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a roll coating apparatus for coating a web that is continuously conveyed using a coating roll, and a method for producing a web on which a coating film is formed.

  As a coating apparatus for forming a coating film on a continuously conveyed web, a roll coating apparatus using a coating roll for continuously transferring a coating liquid to the web is known, and various types Used in the field. As a system of such a roll coating apparatus, a gravure coating system and a kiss coating system are known.

  In a gravure coating type roll coating apparatus (hereinafter referred to as “gravure coater”), as shown in FIG. 6, the web 1 is continuously guided while being guided by an introduction side guide roll F1 and a lead-out side guide rail F2. After the gravure roll G, which is the coating roll A that is conveyed and rotated, is immersed in the coating liquid 2 in the coating liquid tank H, it is brought into contact with the web 1 that is continuously conveyed. On the surface of the gravure roll G, a large number of fine liquid reservoir recesses (hereinafter also referred to as “cells”) g are formed. Fill with coating solution. Further, immediately after the immersion, the doctor blade D is brought into contact with the surface of the gravure roll G, and excess coating solution is rubbed off from the roll surface so that a certain amount of coating solution remains in the cell. Further, at a point where the gravure roll G contacts the web, the web is pressed with high pressure by the pressing roller E from the back side. Thereby, the coating liquid in a cell is transferred to the web surface by capillary action and pressing force, and a coating film can be accurately formed on the web (for example, refer to Patent Document 1).

  As shown in FIG. 7, a roll coating apparatus such as a kiss coating system (hereinafter referred to as “kiss coater”) continuously guides the web 1 while being guided by an introduction side guide roll F <b> 1 and a lead-out side guide rail F <b> 2. A web that is continuously transported after the coating roll 3 that is transported and rotated, which is a coating roll 3 having no irregularities formed on the surface thereof, is immersed in the coating liquid 2 in the coating liquid tank H. The coating liquid is transferred to the web surface by being brought into contact with 1. The surface of the coating roll 3 does not have the fine liquid reservoir recesses that the surface of the gravure roll G has, and is a smooth curved surface. In the kiss coater, since the concave portion for liquid storage is not provided on the roll surface, the pressure roller used in the gravure coater is not used.

JP-A-5-317771

  In the gravure coater shown in FIG. 6, the coating liquid accurately measured by the cell g and the doctor blade D on the surface of the gravure roll G can be transferred to the web. Can be formed. For this reason, it can be widely applied to products that require a high-quality coating film. However, since many fine cells need to be formed on the surface of the gravure roll G by laser engraving, chemical etching, machining, or the like, the equipment cost tends to increase. In addition, since there is a risk of cell clogging during the operation process, frequent maintenance is required to stabilize the quality. Furthermore, since the roll is rotated while the doctor blade D is in contact with the surface of the gravure roll G, the doctor blade or the roll surface may be worn or chipped, and frequent maintenance is also required in this respect. Furthermore, since the coating liquid in the cell is transferred to the web surface, the cell pattern may be transferred to the coating film on the web.

  On the other hand, in the kiss coater shown in FIG. 7, since no cells are provided on the roll surface and no doctor blade is used, the equipment cost and the maintenance cost can be suppressed, and the problem that the cell pattern is transferred does not occur. . On the other hand, since there is no means for accurately measuring the coating liquid transferred to the web like a gravure coater, the coating film thickness varies in the width direction (direction perpendicular to the transport direction). There's a problem. This problem is particularly noticeable when the web is conveyed and coated at a high speed for the purpose of improving productivity.

  In view of the above-mentioned present situation, the present invention is advantageous in that, when coating is performed on a continuously conveyed web using a coating roll, the manufacturing cost and maintenance cost are suppressed, and the cell pattern is not transferred to the coating film. The object is to suppress variations in the thickness of the coating film in the width direction.

The present invention is a roll coating apparatus for coating a continuously conveyed web,
A coating liquid supply means for supplying the coating liquid;
The coating liquid supplied from the coating liquid supply means is attached to the surface, rotated, and brought into contact with the full width of one side of the conveyed web, thereby transferring the coating liquid to the full width of the one side of the web. A coating roll to make,
A blade disposed toward the surface of the coating roll to which the coating liquid before transferring to the web is attached;
A pressing means for pressing the entire width of the other surface of the web toward the coating roll at a position where the coating roll contacts one surface of the web;
The coating roll is one that does not have a liquid reservoir recess on the roll surface,
The blade is arranged so as not to contact the surface of the coating roll but to contact the coating liquid adhering to the surface of the coating roll over a width greater than the width of the web. And
The present invention relates to a roll coating apparatus.

  Preferably, the width of the gap between the blade and the surface of the coating roll is 5 to 100 μm.

  The present invention also relates to a method for producing a web on which a coating film is formed, wherein the roll coating apparatus is used to coat a web that is continuously conveyed.

  Preferably, the other surface of the web is pressed by the pressing means at a linear pressure of less than 200 N / m.

  Preferably, the web is conveyed at a conveyance speed of 20 m / min or more.

The roll coating apparatus according to the present invention and the method for producing a web on which a coating film is formed have the following remarkable effects.
(1) Since neither a gravure roll with many fine cells on its surface nor a doctor blade that contacts the roll surface is used, manufacturing costs and maintenance costs can be reduced, and the cell pattern is transferred to the coating film. Therefore, a flat coating film can be formed. Furthermore, since frequent maintenance is not required, continuous productivity is high, and quality stability during continuous production is high.
(2) Although it is not in contact with the surface of the coating roll, a proximity blade disposed so as to be in contact with the coating liquid film on the surface of the coating roll over the entire width is provided before the coating roll contacts the web. Therefore, before the coating liquid is transferred to the web, the thickness of the coating liquid film on the coating roll can be leveled in the width direction. As a result, the coating film thickness variation in the width direction can be reduced. Can be suppressed. In particular, even when the web is conveyed and coated at a high speed, variations in the thickness of the coating film in the width direction can be suppressed.
(3) In order to transfer the coating liquid to the web while pressing the back surface of the web with the pressing means at the position where the coating roll comes into contact with the web, the coating liquid film is applied to the continuously conveyed web. The film can be transferred uniformly in the width direction with a desired thickness.

The longitudinal cross-sectional view which shows the structure of the roll coating apparatus which concerns on one Embodiment of this invention. The longitudinal cross-sectional view which shows an example of the specific structure of the coating roll and press roll in the roll coating apparatus which concerns on one Embodiment of this invention. The longitudinal cross-sectional view which shows the structure of the roll coating apparatus which concerns on another embodiment of this invention. The longitudinal cross-sectional view which shows the structure of the roll coating apparatus which concerns on another embodiment of this invention. The figure which shows the film thickness distribution of the coating film in the width direction measured by each Example and the comparative example Conceptual diagram showing the structure of a conventional gravure coater Conceptual diagram showing the structure of a conventional kiss coater

  Hereinafter, the present invention will be described in detail.

  The roll coating apparatus of the present invention is an apparatus for continuously coating a web surface while continuously conveying a belt-shaped web, and includes at least a coating liquid supply means, a coating roll, , A blade, pressing means, and a web conveying device. Furthermore, you may have a heating means which heats the coating liquid of a web surface, and a winding means which winds up a web.

(web)
The web in the present invention is obtained by forming a flexible film or sheet-like base material having a uniform thickness into a long band shape. Although it does not specifically limit as a material which comprises the said base material, For example, resin, paper, cloth, a metal etc. are mentioned, It can select suitably according to a use. Specific examples of the resin include, for example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymers; acrylic polymers such as polymethyl methacrylate; polystyrene, acrylonitrile- Styrene polymers such as styrene copolymers; polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, olefin polymers such as ethylene-propylene copolymers; vinyl chloride polymers; nylon (aliphatic polyamide), aromatic polyamides, etc. Amide polymers; polyimide polymers; blends of these polymers, and the like.

(Coating liquid supply means)
The coating liquid supply means in the present invention is the coating liquid tank 2 that stores a required amount of the coating liquid in the case shown in FIGS. 1 to 3, or the coating liquid in the case shown in FIG. The tank 2 and the pumping roll 10. The lower part of the coating roll or the lower part of the pumping roll 10 enters the upper part of the coating liquid tank so that the lower part of the coating roll or the lower part of the pumping roll 10 can be immersed in the coating liquid in the coating liquid tank. It has an opening that can.

  The coating liquid in the present invention is a resin liquid capable of forming a coating film by drying, curing and the like after coating on a web. The resin material contained in the coating solution is not particularly limited, and examples thereof include various polymers such as polyurethane, polycycloolefin, polycarbonate, polyester, polyether ketone, polyamide, polyimide, polyamide-imide, and polyester-imide. Can do. Any one of these polymers may be used alone, or for example, a mixture of two or more kinds having different functional groups such as a mixture of polyetherketone and polyamide. Furthermore, fillers such as carbon black, metal, and ceramics may be mixed. Drying and curing conditions are not particularly limited, and may be general conditions. Moreover, when hardening these materials, the hardening process according to materials, such as drying solidification, thermosetting, and ultraviolet curing, can be selected.

  The resin liquid may contain a solvent that dissolves the resin material or a dispersion medium that disperses the resin material. Such a solvent or dispersion medium is not particularly limited, and can be appropriately selected according to the resin material and web to be used. Specifically, for example, halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, o-dichlorobenzene; phenols such as phenol and p-chlorophenol; methanol Alcohols such as ethanol; aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene; acetone, ethyl acetate, t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene Glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol, ethyl cellosolve, Use tilselsolve, 2-pyrrolidone, N-methyl-2-pyrrolidone, pyridine, triethylamine, dimethylformamide, dimethylacetamide, acetonitrile, butyronitrile, methyl isobutyl ketone, methyl ether ketone, cyclohexane, cyclopentanone, carbon disulfide, water, etc. be able to. These solvents or dispersion media can be used alone or in combination of two or more.

(Coating roll)
The coating roll in the present invention is supplied with the coating liquid from the coating liquid supply means, rotates with the coating liquid attached to the surface thereof, contacts the web, and transfers the coating liquid to the web. It is a rotating body. The coating roll in the present invention does not have the fine liquid reservoir recesses of the gravure roll on the roll surface, and the roll surface is smoothly formed. The width of the coating roll is larger than the width of the web, and the coating roll can contact the entire width of the web and transfer the coating solution to the entire width of the web.

  As shown in FIG. 1, the coating roll may be immersed in the coating liquid in the coating liquid tank 2, and the coating liquid may be supplied directly from the coating liquid tank 2 to the coating roll. As shown in, the drawing roll 10 and the coating roll immersed in the coating liquid in the coating liquid tank 2 are contacted and rotated without immersing the coating roll in the coating liquid in the coating liquid tank 2, The coating liquid may be supplied to the coating roll through the pumping roll 10.

(blade)
The tip of the blade in the present invention is arranged toward the surface of the coating roll to which the coating liquid before transferring to the web is attached. Unlike the doctor blade used in the gravure coater, the blade in the present invention is not in contact with the surface of the coating roll. However, it is disposed in the vicinity of the coating roll and is disposed with a gap between the coating roll and the coating roll so as to come into contact with the coating liquid adhering to the coating roll surface. Therefore, the blade of the present invention can also be referred to as a “proximity blade”. The proximity blade has a width of the tip portion larger than the width of the web and contacts the coating liquid on the surface of the coating roll over the width of the web or more, and the thickness of the coating liquid film on the surface of the coating roll Can be leveled.

  The proximity blade is intended to make the thickness of the coating film on the coating roll surface uniform, so the width of the gap between the proximity blade and the coating roll is set to be constant in the width direction. Has been. In addition, the proximity blade, at least in the coating liquid film of the width that the coating liquid is transferred to the web in the next stage, will equalize its thickness, but the coating liquid film over the entire width of the coating roll It is preferable to be configured so that the thickness can be equalized.

  The shape of the proximity blade is not particularly limited. For example, a doctor blade used in a gravure coater can be used as a proximity blade in the present invention. The material constituting the proximity blade is not particularly limited, and examples thereof include metal, resin, FRP, and rubber.

  The proximity blade is provided with a holding portion at either end, and the proximity blade is supported by the holding portion. The proximity blade is disposed so as to be movable using a thrust such as a feed screw or an air cylinder. Thereby, the width | variety of the clearance gap between a proximity | contact blade and a coating roll can be set arbitrarily.

  The width of the gap between the proximity blade and the coating roll is not particularly limited. The thickness of the coating liquid film on the surface of the coating roll, the viscosity of the coating liquid, and the angle of the proximity blade with respect to the rotation direction of the coating roll. Etc. can be set as appropriate. However, if the width of the gap becomes too large, it will be difficult to obtain the effect of leveling the thickness of the coating liquid film adhering to the coating roll surface. Is preferred. Specifically, the width of the gap is preferably less than 200 μm, more preferably 180 μm or less, further preferably 150 μm or less, and particularly preferably 100 μm or less. The lower limit is not particularly limited, but if the width of the gap becomes too small, the proximity blade and the coating roll may come into contact with each other, preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

(Pressing means)
In the present invention, the pressing means contacts the back surface of the web at a position where the coating roll contacts the web and presses the back surface toward the coating roll. Thereby, the coating liquid film can be uniformly transferred on the web in the width direction with a desired thickness. The pressing means presses the back surface of the web with the same pressing over the entire width of the web in order to uniformly transfer the coating liquid film in the width direction.

  The thickness of the coating liquid film transferred to the web surface is substantially determined by the pressing force by the pressing means. From the viewpoint of uniformly transferring the coating liquid film having a desired thickness in the width direction of the web by the pressing means, the pressing force can be appropriately determined in consideration of the viscosity and surface tension of the coating liquid. However, in the conventional gravure coater, since the coating liquid in the cell is transferred to the web, it is necessary to set the pressing force by the pressing means to be high, but in the present invention, the coating roll has a smooth surface. The pressing force by the pressing means does not need to be as high as that of the gravure coater. On the other hand, if the pressing force becomes too high, coating omission or reverse may occur. From this viewpoint, in the present invention, the pressing force by the pressing means is preferably set to a linear pressure of less than 200 N / m, more preferably 150 N / m or less, and even more preferably 100 N / m or less. Further, if the pressing force is too low, it becomes difficult to obtain the effect of uniforming the thickness of the coating liquid film transferred to the web. Therefore, the linear pressure is preferably set to 30 N / m or more, and 40 N / m m or more is more preferable, and 50 N / m or more is more preferable.

  The specific configuration of the pressing means is not particularly limited as long as it can press the entire width of the web toward the coating roller, and may be a contact-type pressing means such as a pressing roll or a pressing plate, Non-contact type pressing means that presses using the pressure of a gas such as air or nitrogen may be used.

  It does not specifically limit as a material which comprises a press roll, Any one types, such as a metal, resin, rubber | gum, may be sufficient, or several combinations may be sufficient. The pressing roll is preferably an elastic roll having an elastic layer on the roll surface. The elastic body forming the elastic layer is not particularly limited, and examples thereof include natural rubber, styrene butadiene rubber, nitrile rubber, chloroprene rubber, butyl rubber, ethylene propylene rubber, silicon rubber, fluorine rubber, and urethane rubber.

(Transport device)
The roll coating apparatus of the present invention further includes a transport device for continuously transporting the web. The speed at which the web is conveyed is not particularly limited, but the effect of the present invention can be obtained at a low speed or a high speed. In the conventional method, for example, when the film is conveyed at a high speed of 10 m / min or more, the problem of uneven coating film thickness in the width direction is likely to occur. According to the present invention, the coating is performed even in such a high-speed conveyance. Variations in the film thickness of the film can be suppressed. The conveyance speed in the present invention is preferably 10 m / min or more, more preferably 15 m / min or more, and further preferably 20 m / min or more.

  Moreover, the roll coating apparatus of the present invention may further have a heating means for transferring or drying the coating liquid after transferring the coating liquid to the web, and the coating film is formed. You may have further the winding-up means for winding up a web.

(Production method)
By operating the roll coating apparatus of the present invention, the web surface can be continuously coated while the belt-like web is continuously conveyed. According to the production method of the present invention, first, the coating liquid is supplied from the coating liquid supply means to the coating roll, and the coating roll rotates with the coating liquid attached to the surface. Next, the coating liquid adhering to the rotating coating roll surface comes into contact with the proximity blade, and the thickness of the coating liquid film is made uniform in the web width direction. The coating roll having a coating liquid film with a uniform thickness on the surface continues to rotate and contacts the web, but the back surface of the web at the contact position is pressed by the pressing means. By continuously performing the above steps, the coating liquid film can be continuously transferred onto the web with a uniform thickness in the width direction.

(First embodiment)
FIG. 1 is a longitudinal sectional view showing a configuration of a roll coating apparatus according to an embodiment of the present invention. Here, the web 1 is continuously conveyed from the coating roll 3 which is a coating roll A which is immersed and rotated in the coating liquid 2 in the coating liquid tank H and which does not have a liquid reservoir recess on the surface. The coating liquid is transferred to form a coating liquid film 4 on the lower surface of the web 1.

  The web 1 is guided so as to come into contact with the introduction-side guide roll F1, the coating roll 3, and the outlet-side guide rail F2 in this order. Each of the contact surface of the web 1 and the introduction side guide roll F1 and the contact surface of the web 1 and the outlet side guide rail F2 are vertically lower than the contact surface of the web 1 and the coating roll 3. Roll is placed. With this arrangement, the web 1 is guided along a route in which the contact surface with the coating roll 3 protrudes upward as shown in FIG.

  Explaining along the rotation direction of the coating roll 3, the coating roll 3 is submerged in the coating liquid 2 in the coating liquid tank H and moved in the coating liquid 2. Surface. The coating liquid adheres to the surface of the coating roll 3 that has floated. A proximity blade 11 is arranged perpendicular to the rotation direction of the coating roll 3 toward the surface of the coating roll 3 to which the coating liquid has adhered. When the proximity blade 11 comes into contact with the coating liquid adhering to the surface of the coating roll 3, the thickness of the coating liquid film on the roll surface is leveled in the width direction. Then, although the coating roll 3 surface contacts the lower surface of the web 1, the back surface (upper surface) is contacting the press roll 5 which is the press means B. FIG. The coating roll 3 and the pressing roll 5 are arranged so as to sandwich the web 1. The width of the coating roll 3 and the pressing roll 5 is larger than the width of the web 1, and the entire width of the web 1 is the coating roll 3 and the pressing roll. It is sandwiched between rolls 5. The pressing roll 5 presses the web 1 while rotating in the direction opposite to the coating roll 3. Thereby, the coating liquid on the surface of the coating roll 3 is transferred to the web.

  FIG. 2 is a longitudinal sectional view showing an example of a specific configuration of the coating roll and the pressing roll in the roll coating apparatus according to the embodiment of the present invention. Here, an adjusting means C for adjusting the pressing force by the pressing roll 5 is provided. The frame 7 as a fixing member supports the rotating shaft 3A of the coating roll 3 with a bearing (not shown). Further, the frame 7 supports a shaft support 8 that supports the rotating shaft 5A of the pressing roll 5 with a bearing (not shown) so as to be slidable in the vertical direction. The shaft support 8 can be driven in the vertical direction by an air cylinder 6 which is the adjusting means C. The pressing roll 5 is pressed toward the coating roll 3 and the web 1 by its own weight including the bearing and the shaft support 8 and the thrust of the air cylinder 6. By adjusting the thrust of the air cylinder 6, the pressing force by the pressing roll 5 can be adjusted.

  The air cylinder 6 adopts a double-acting type. For example, when it is desired to apply a pressing force that is greater than the self-weight (W), a thrust (F) is generated downward by a rod of the air cylinder 6 so that the self-weight ( A resultant force (W + F) obtained by adding a thrust (F) to W) can be applied to the web 1. Conversely, when it is desired to apply a pressing force smaller than the self-weight (W), a force obtained by subtracting the thrust (F) from the self-weight (W) by generating a thrust (F) upward by the rod of the air cylinder 6. (WF) can act on the web 1. The magnitude of the thrust (F) can be adjusted by adjusting the air pressure supplied to the air cylinder 6. Thus, by configuring the pressing force adjusting means C with the air cylinder 6, the pressing force adjusting means C can be configured simply and reliably using, for example, air equipment in a factory.

(Second embodiment)
FIG. 3 is a longitudinal sectional view showing a configuration of a roll coating apparatus according to another embodiment of the present invention. In this embodiment, a backup roll 9 that rotates in the opposite direction in contact with the pressing roll 5 is provided on the upper part of the pressing roll 5, and other than this point is the same as the embodiment shown in FIG. The backup roll 9 can prevent the pressing roll 5 from being bent. The specific configuration of the backup roll 9 is not particularly limited as long as the backup roll 9 is a roll that can apply pressure to the pressure roll 5 so as to prevent the pressure roll 5 from being bent.

(Third embodiment)
FIG. 4 is a longitudinal sectional view showing a configuration of a roll coating apparatus according to still another embodiment of the present invention. In this embodiment, a pumping roll 10 that contacts the coating roll 3 and rotates in the opposite direction is provided below the coating roll 3. Here, the coating roll 3 does not dive into the coating liquid 2 in the coating liquid tank H. Instead, the pumping roll 10 dives and then floats. The coating liquid adhering to the surface of the pumping roll 10 that has floated is transferred to the surface of the coating roll 3 by the contact between the pumping roll 10 and the coating roll 3. After that, it is the same as the embodiment shown in FIG. As the drawing roll 10, similarly to the coating roll 3, it is possible to use a roll that does not have the fine liquid reservoir concave portion of the gravure roll on the surface and has a smooth surface.

  The roll coating apparatus of the present invention and the method for producing a web on which a coating film is formed include an optical film, a magnetic recording tape, an adhesive tape, a photographic printing paper, an offset plate material, a battery electrode plate, a fuel cell catalyst layer, and the like. It can use suitably in each manufacture. An example of the optical film includes an optical film having an adhesive layer, an antireflection layer, a refractive index adjusting layer, and an antiglare layer on the web.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

  In the following Examples and Comparative Examples, the web was continuously coated with a roll coating apparatus, and the formed coating film was evaluated.

(Roll coating device)
A roll coating apparatus having the configuration shown in FIG. 1 was used. The coating roll is a carbon steel roll with hard chrome plating on the surface, and a roll with a diameter of 180 mm and a width of 400 mm is used. As a pressing roll, a rubber roll with a diameter of 60 mm and a width of 400 mm is used. did. As the proximity blade, a plate-like blade having a width of 390 mm, a tip thickness of 0.2 mm, and a material of SUS420 was used.

(web)
As the web, an acrylic film having a thickness of 40 μm and a width of 350 mm was used.

(Coating fluid)
Cross-linking agent (trade name: EPOCROSS WS700, manufactured by Nippon Shokubai Co., Ltd., solid content: 25%) with respect to 200 g of water-based urethane resin (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Superflex 210, solid content: 33%) 40 g was added and stirred to obtain a coating solution.

<Examples and Comparative Examples>
Example 1
Both are arranged so that the width of the gap between the adjacent blade and the coating roll is 5 μm over the entire width in the width direction of the web, the web conveyance speed is set to 20 m / min, and the pressing force of the pressing roll is set to a linear pressure of 100 N. The coating was continuously performed at a setting of / m. Then, it was made to dry and the web by which the coating film about 50 m in length was formed on one side was obtained.

(Example 2)
A web having a coating film formed on one side was obtained in the same manner as in Example 1 except that the width of the gap between the proximity blade and the coating roll was changed to 50 μm.

(Example 3)
A web with a coating film formed on one side was obtained in the same manner as in Example 1 except that the width of the gap between the proximity blade and the coating roll was changed to 100 μm.

(Comparative Example 1)
A web having a coating film formed on one side was obtained in the same manner as in Example 1 except that the proximity blade was not used.

<Evaluation test method>
About the web in which the coating film was formed in the single side | surface obtained in each Example and the comparative example, the film thickness distribution of the coating film in the width direction (perpendicular to a conveyance direction) was measured. The film thickness distribution of the coating film was measured by spectral interference using a F20 manufactured by Filmetrics Co., Ltd. at a point 40 m from the coating start point. The obtained results are shown in FIG.

<Evaluation test results>
In each of Examples 1 to 3, the coating film thickness is almost uniform over the entire width of the web, and the difference between the maximum film thickness and the minimum film thickness is only about 30 nm. In these examples, the proximity blade is disposed so as to be in contact with the coating liquid film on the surface of the coating roll over the entire width, so that the coating liquid adhesion amount at the center of the roll and the coating at both ends of the roll are applied. It is considered that the liquid adhesion amount was made uniform, and as a result, the coating film thickness could be made uniform.

  On the other hand, in Comparative Example 1, as compared with Examples 1 to 3, the film thickness of the coating film is increased over the entire width of the web, and obviously, the film thickness at the center of the web is at the both ends of the web. It was larger than the film thickness, and the difference between the maximum film thickness and the minimum film thickness was about 200 μm. This is because the proximity blade is not used in Comparative Example 1, so that the coating liquid adhesion amount to the coating roll is larger at the roll center than at both ends of the roll, and as a result, the coating at the web center is performed. This is thought to be because the amount of liquid transfer is greater than that at both ends of the web.

  When the web is transported at a low speed, the thickness of the coating film can be made uniform by using only the pressing roll without using the proximity blade as in Comparative Example 1. is there. However, in Comparative Example 1, since the web is conveyed at a high speed of 20 m / min, it is considered that the thickness of the coating film cannot be uniformed only by the pressing roll.

  Moreover, in Examples 1-3, although the width | variety of the clearance gap between a proximity | contact blade and a coating roll is significantly different with 5-100 micrometers, the film thickness of the coating film formed is about 300 nm and all are comparable. It can be seen that the width of the gap does not affect the final film thickness. This is because the final coating film thickness is adjusted by pressing with a pressing roll after the proximity blade.

DESCRIPTION OF SYMBOLS 1 Web 2 Coating liquid 3 Coating roll 3A whose surface is smooth Rotating shaft 4 Coating liquid film 5 Press roll 5A Rotating shaft 6 Air cylinder 7 Frame 8 Shaft support 9 Backup roll 10 Lifting roll 11 Proximity blade A Coating roll B Pressing means C Pressing force adjusting means D Doctor blade E Pressing roll F Thrust F1, F2 Guide roll G Gravure roll g Reservoir recess H Coating liquid tank W Own weight

Claims (5)

A roll coating apparatus that coats a continuously conveyed web,
A coating liquid supply means for supplying the coating liquid;
The coating liquid supplied from the coating liquid supply means is attached to the surface, rotated, and brought into contact with the full width of one side of the conveyed web, thereby transferring the coating liquid to the full width of the one side of the web. A coating roll to make,
A blade disposed toward the surface of the coating roll to which the coating liquid before transferring to the web is attached;
A pressing means for pressing the entire width of the other surface of the web toward the coating roll at a position where the coating roll contacts one surface of the web;
The coating roll is one that does not have a liquid reservoir recess on the roll surface,
The blade is arranged so as not to contact the surface of the coating roll but to contact the coating liquid adhering to the surface of the coating roll over a width greater than the width of the web. And
Roll coating equipment.   The roll coating apparatus according to claim 1, wherein a width of a gap between the blade and the surface of the coating roll is 5 to 100 μm.   A method for producing a web on which a coating film is formed, characterized in that coating is performed on a continuously conveyed web using the roll coating apparatus according to claim 1.   The manufacturing method of the web in which the coating film of Claim 3 was formed of the said press means pressing the other surface of the said web with a linear pressure of less than 200 N / m. The said web is a manufacturing method of the web in which the coating film of Claim 3 or 4 formed in the conveyance speed of 20 m / min or more was formed.

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