WO2007086530A2

WO2007086530A2 - Method of applying and drying liquid

Info

Publication number: WO2007086530A2
Application number: PCT/JP2007/051316
Authority: WO
Inventors: Masafumi Matsunaga; Shigenori Kitasako
Original assignee: Nordson Corporation
Priority date: 2006-01-24
Filing date: 2007-01-22
Publication date: 2007-08-02
Also published as: TW200734066A; TWI337101B; JP2007196093A; WO2007086530A3; JP4993915B2

Abstract

A method of applying and drying a liquid, by which downsizing of a device and superposed-layer application become possible, and which is high in productive efficiency. The method of applying and drying a liquid includes a placing step (S2) of placing a sheet substrate on a circulating member, an application step (S5, S7) of moving the circulating member and applying a liquid onto the substrate, and a rotation dry step (S6) of rotating the circulating member through a plurality of revolutions to dry the liquid.

Description

DESCRIPTION

METHOD OF APPLYING AND DRYING LIQUID ^■

TECHNICAL FIELD

The present invention relates to a method of applying and drying a liquid, and more particularly, to a method of applying a liquid on a sheet arranged on a circulating member and drying the liquid.

BACKGROUND ART

Up to now, there has been a method of sucking a web to a circulating member and applying a liquid on the moving web (for example, refer to Japanese Patent Application Laid-open No. H10-76220) . According to the method, the liquid is applied on a porous or air- permeability web, and a vacuum is established in the circulating member so that porous portions of the web are liable to be filled with the liquid. In recent years, a method has been attempted, in which a substrate having pores is filled with an electrolyte solution and dried by the above-mentioned method to manufacture a fuel cell electrolyte membrane with high performance . Also, in recent years, with progressive development of a fuel cell, there has been a demand for a method in which a fluid electrode ink is applied on a web-like electrolyte membrane and dried to automatically manufacture an electrolyte membrane- electrode assembly (MEA) (for example, refer to Japanese Patent Application Laid-open No. 2001-70863, Japanese Patent Application Laid-open No. 2004-351413, and Japanese Patent Application Laid-open No. 2004- 63780) . The method in which the electrode ink is directly applied on the electrolyte membrane and then dried to manufacture the MEA has been attracting attention as an ideal electrode forming method that leads to an improvement of performance as compared with another method because an interface resistance between the electrolyte membrane and an electrode layer is extremely low. However, there arises a problem in that the electrolyte membrane is deformed even by humidity, and readily swelled with a solvent of the electrode ink. As a method of solving the problem, there has been proposed a method of sucking a sheet type electrolyte membrane with a heating and sucking plate and applying an electrode ink to produce an MEA (for example, refer to Japanese Patent Application Laid-open No. H05- 507583) . The method employs a so-called batch system in which the electrolyte membrane is sucked to or detached from the sucking plate manually. Also, the method is not suited for automation manufacturing. The techniques disclosed in Japanese Patent Application Laid-open No. H10-76220, Japanese Patent Application Laid-open No. 2001-70863, and Japanese Patent Application Laid-open No. 2004-351413 employ a system in which the electrolyte membrane of a film roll (web) type is sucked by the circulating member and applied with the fluid electrode ink, and the fluid electrode ink is dried while the electrolyte membrane is being sucked. Therefore, the techniques have the feature that an anode and a cathode can be applied and dried on the same line. Although productivity is high, there is a problem in that a device is enlarged and a facility cost becomes high because the fluid electrode ink is over-applied a plurality of times for improving the performance . An MEA for a fuel cell automobile of 60 kW to 90 kW has a large area per one cell, and cells of several hundred sets are required per stack, thereby requiring a large facility with high productivity. Cogeneration is 1 kW to several kW per automobile, so a similar facility is required. However, in a mobile field intended for a direct methanol type fuel cell (DMFC) , the cogeneration is about 1 W to 20-odd W per automobile, and the electrode per sheet of MEA is an extremely small area that is several centimeters * several centimeters. However, automation has been demanded from a viewpoint of quality even with a low production speed in any market. Also, in a case where application is conducted by a slot nozzle and viscosity of the electrode ink is low, a flow rate per unit time is large, thereby making it necessary to conduct the application at a higher web speed. A plurality of numbers of applications are required, and it is necessary to increase a size of the circulating member as the number of applications increases .

DISCLOSURE OF THE INVENTION

The present invention has been made to solve the above-mentioned problem, and therefore proposes an inexpensive and space saving device which is capable of superposing and applying a liquid to even a sheet or a relatively long sheet, and drying the liquid by using a small circulating member.

An object of the present invention is to provide a method of applying a liquid to a sheet and drying the liquid. Another object of the present invention is to downsize an applying and drying device and to provide a method of applying and drying a liquid with high productive efficiency. In Japanese Patent Application Laid-open No. H05-507583 described above, in a case where a sheet like electrolyte membrane which is, for example, 300 mm in width x 900 mm in length is sucked to a heating and sucking plate, and an electrode ink is applied to the electrolyte membrane, the heating and sucking plate of 450 mm in width * 1050 mm in length has been required from a viewpoint of temperature distribution. Also, since a traverse length of a spray nozzle is required to cover the length of 900 mm, 1200 mm has been required in order to stably maintain a traverse speed of lm/sec. Also, in trying to increase the traverse speed so as to' enhance productivity, a speed limit has been 1.5 m/sec from viewpoints of stiffness and durability of the device. Also, as the speed is increased, a spray flow is fanned to scatter particles. As a result, cleaning becomes bothersome. Also, a table requires a traverse movement of pitch feed in an orthogonal direction in view of an explosion proof construction, so a table type device is enlarged accordingly and also by a weight of the table. On the other hand, in a case of using a slot nozzle, it has been impossible to maintain flatness of a large-sized metal plate by micron order when the table is heated. Still more, in a case of providing a suction configuration, it has been further difficult to maintain the flatness of the metal plate. For that reason, it has been impossible to stably obtain the applied film of about 10 μm. Still another object of the present invention is to provide a method of applying and drying a liquid, by which effective superposed layer application of with a single nozzle becomes possible. ^*

In- order to solve the above-mentioned problems, according to the present invention, there is provided a method of applying and drying a liquid as described below. For example, when the table type device is replaced with a circulating member, a roll that is 300 mm in diameter and 320 mm in face length is only necessary, and the traverse length of pitch feed may only be 320 mm. The traverse speed of the spray nozzle can be compared with a circumferential speed of the circulating member. The traverse speed is 1.57 m/sec at 100 RPM, and the traverse speed can exceed 3 m/sec, which cannot be performed by a traverse mechanism, when the circumferential speed of the circulating member is 200 RPM. Because of a rotation mechanism, the device can be downsized without any vibration. In addition, the device can be further downsized even when there is employed a spray method, since the scattered particles can be locally trapped by a mechanism shown in FIG. 1. Also, it is possible to achieve a production speed of ten times or more as a normal low-s.peed traverse speed (0.3 m/sec) even in the spray method.

On the other hand, even in the case of using the slot nozzle, a technique of controlling roundness of the roll within ±1 μm even when being heated is not difficult in this industry. Also, a viscosity range of the liquid for use is wide, but the following needs to be taken into consideration. In a case of a viscosity of 5000 mPa-s to 20000 mPa-s, it is possible to apply a wet film of 20 μm at a speed of 1 to 2 m/min. However, in a case of a low viscosity of 50 to 200 mPa*s, it is necessary to set the speed to 15 m/min or higher.

Since the electrode ink of the fuel cell is 7 to 15^' wt% in solid content and about 10 μm in thickness of a dry film, it is preferable that the coated films are superposed ten times when the wet is 10 μm, and five times while being dried when the wet is 20 μm.

According to an aspect of the present invention, there is provided a method of applying and drying a liquid as described below.

That is, there is provided a method of applying and drying a liquid, including: a placement step (S2) of placing a sheet substrate (P) on a circulating member (2); an application step (S5, S7) of applying a liquid on the substrate while rotating the circulating member; and a rotation dry step (S6, S21, S22, S23, S42, S44) of rotating the circulating member through a plurality of revolutions to dry the liquid.

Further, according to another aspect of the present invention, a method of applying and drying a liquid may be as follows.

That is, there may be provided a method of applying and drying a liquid, including: a placement step (S2) of placing a sheet substrate (P) on a circulating member (2) ; an application step (S5, S7) of moving the circulating member and applying a liquid on the substrate by at least one applying device (3) ; a dry step (S3, S9) of promoting drying of the liquid; and a multilayer coating application step (S6, S23, S44) of applying a plurality of layer coatings by repeating the application step and the dry step.

The method of applying and drying a liquid may include a dry step (S3, S9) of drying the liquid applied on the substrate by at least one of cold air, warm air, hot air, radiation heat, and heat transmission of heating means of the circulating member.

The placement step may include a suction step of sucking the substrate on the circulating member with vacuum.

The method of applying and drying a liquid may include a substrate heating step of heating the substrate before the application step. The placement step may include a step of placing an air-permeability member between the circulating member and the substrate.

The placement step may include a step of placing a masking member on the substrate. The substrate may be an electrolyte membrane.

The liquid may be an electrode ink.

The application step may include a dispensing application step of dispensing the liquid from a slot nozzle (33) to apply the liquid onto the substrate.

The application step may include a spray application step of spraying the liquid from a spray nozzle (3) to apply the liquid onto the substrate.

The multilayer coating application step may include a dispensing application step of dispensing the liquid from a slot nozzle to apply the liquid onto the substrate, and a spray application step of spraying the liquid from a spray nozzle to apply the liquid onto the substrate.

The spray application step may include a step (S31, S32, S45) of moving the spray nozzle in a traverse direction when each application in one revolution of the circulating member is ended.

The spray application step may include a step (S22) of rotating the circulating member through one or more revolutions between a spray application and a spray application. The dispensing application step may include a step of operating one slot nozzle intermittently to apply the liquid onto a plurality of application areas.

The dispensing application step may include a step of rotating the circulating member through one or more revolutions between a dispensing application and a dispensing application.

Further, a membrane electrode assembly may be formed by applying an electrode ink to an electrolyte membrane by using the method of applying and drying a liquid.

Further, one of a polyelectrolyte membrane fuel 5. cell and a direct methanol fuel cell, which uses a membrane electrode assembly formed as described above may be manufactured.

According to the present invention, the applying and drying device can be downsized, and a liquid can be 0 applied and dried on a sheet with high productive ■ efficiency.

According to the present invention, it is possible to promote the drying of the liquid.

According to the present invention, the liquid 5 can be efficiently superposed and applied onto a substrate by a single nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram showing 0 a liquid applying and drying device according to a first embodiment.

FIG. 2 is a flowchart showing the procedure of a method of applying and drying a liquid according to the first embodiment. 5 FIG. 3 is a flowchart showing the procedure of a method of applying and drying a liquid according to a second embodiment. FIG. 4 is a plan view showing a liquid applying and drying device according to a third embodiment.

FIG. 5 is a flowchart showing the procedure of a method of applying and drying a liquid according to the third embodiment.

FIG. 6 is a flowchart showing the procedure of a method of applying and drying a liquid according to a fourth embodiment .

FIGS. 7A, 7B, 7C, 7D, and 7E are schematic diagrams showing coated films that are formed through the liquid applying and drying method according to the fourth embodiment .

FIGS. 8A, 8B, and 8C are diagrams showing coated film patterns according to a fifth embodiment. ^' FIG. 9 is a schematic structural diagram showing a liquid applying and drying device according to a sixth embodiment.

FIG. 10 is a plan view showing the liquid applying and drying device according to the sixth embodiment.

FIGS. HA and HB are schematic structural diagrams showing a slot nozzle.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a description will be given of preferred embodiments of the present invention with reference to the drawings. The scope of the present invention is not limited to the dimensions, the materials, the configurations, and the relative arrangements of structural parts, which are described in the following embodiments so far as a specific description is not particularly made. (First Embodiment) (Applying and drying device)

FIG. 1 is a schematic structural view showing a liquid applying and drying device 1 according to a first embodiment.

The applying and drying device 1 is made up of a circulating member 2 that is capable of rotating in a direction indicated by an arrow A, a spray nozzle 3 , that functions as an applying device for applying a liquid, and an air blower 4 for forming an air flow in the vicinity of an applied surface.

A substrate P of a cut sheet type is disposed on the circulating member 2. The substrate P may be formed of, for example, a sheet like thin film, an air- permeability base material, a release film, a fuel cell gas diffusion substrate, a fuel cell electrolyte membrane, or an electrode formation base film of a dye sensitized solar cell. The substrate P is attached^' onto a peripheral surface of the circulating member 2 by the aid of appropriate means. The fixation of the substrate P to the circulating member may be executed by any means such as fixation with a tape, and this embodiment uses means for sucking the substrate P on the peripheral surface of the circulating member 2 with vacuum. In other words, the circulating member 2 is formed of a cylindrical drum having air-permeability, and a vacuum is created in the interior of the drum by a vacuum device (not shown) . With the above-mentioned configuration, the substrate P is sucked and fixed onto the surface of the circulating member 2.

When the circulating member 2 that sucks the substrate P is rotated, the spray nozzle 3 applies the liquid to the substrate P. The liquid that is sprayed from the spray nozzle 3 may be, for example, paint, an adhesive, fuel cell electrode ink, or an electrolyte solution. Excessive liquid spray that has not been attached to the substrate P is moved in a direction indicated by the arrow F, and then sent to an exhaust processing device through an exhaust port 5.

Liquid spray that has been applied to the substrate P is moved in a direction indicated by the arrow A, and then fed to the air blower 4. The air flow from the air blower 4 evaporates the solution from the liquid, and promotes the drying of the liquid. The solution is sent to an exhaust processing device through an exhaust port 6 with the air flow indicated by an arrow G. The air blower 4 may blow a warm air or a hot air. It is possible that an oil hole (not shown) for allowing a heat medium for heating to pass therethrough is provided in the circulating member 2 to heat the circulating member 2. The substrate P is heated by the heat transmission from the surface of the circulating member 2 to promote the drying of the liquid.

Alternatively, the drying of the liquid may be promoted by the aid of light irradiation or radiation heat. The exhaust port 5 of the excessive liquid spray and the exhaust port 6 for heat air are isolated by partition walls 7 and 8. A space 9 between the partition wall 7 and the partition wall 8 communicates with the atmosphere. As described above, the reason that the exhaust ports 5 and 6 are isolated from each other is because the excessive liquid spray is prevented from being ignited by the heated air. (Masking Sheet)

A masking sheet may be disposed on the substrate P. The masking sheet has an aperture in correspondence with the configuration of an area on which the liquid is to be applied. When the masking sheet is disposed on the substrate P, and the liquid is sprayed to the masking sheet, an application pattern of a desired configuration can be precisely applied to the substrate P.

(Underlay Sheet) An underlay sheet may be disposed between the substrate P and the circulating member 2 as an air- permeability sheet. The use of the underlay sheet makes it possible to prevent the circulating member 2 from being stained by the scattered liquid, and to stick the scattered liquid to the underlay sheet to restore the scattered liquid.

(Applying and Drying Method)

FIG. 2 is a flowchart showing the procedure of a method of applying and drying a liquid according to the first embodiment.

When a liquid applying and drying process starts (Step Sl) , the substrate P is placed on the circulating member 2. The substrate P is sucked on the surface of the circulating member 2 with a vacuum suction. The air blower 4 is driven to start blowing air (Step S3) . The circulating member 2 is rotated (Step S4), and the liquid is applied to the substrate P from the spray nozzle 3 (Step S5) . When the circulating member 2 rotates by one revolution after the application of the liquid starts, one coated film layer is formed on the substrate P. When the circulating member 2 rotates by two revolutions, another coated film layer is formed on the one coated film layer to thus form two coated film layers. In. this way, ten coated film layers are formed when the circulating member 2 rotates by ten revolutions, and twenty coated film layers are formed when the circulating member 2 rotates by twenty revolutions. In Step S6, it is determined whether a predetermined number of revolutions of the circulating member 2 have been completed, or not. In the case where the predetermined number of revolutions of the circulating member 2 have been completed, the application of the liquid stops (Step S7).. With the above operation, a desired number of coated film layers are formed on the substrate P.

The rotation of the circulating member 2 stops (Step S8), and the air blower 4 stops (Step S9) . The substrate P is removed from the circulating member 2 (Step SlO) , to complete the liquid applying and drying process (Step SlI) .

According to this embodiment, it is possible to form a plurality of coated film layers by one spray nozzle.

(Second Embodiment) (Idling)

In a second embodiment, in order to promote the drying of the liquid, an idling process of the circulating member is provided during the liquid applying process. For example, the circulating member 2 rotates by one revolution while the liquid is applied from the spray nozzle 3 to form a first coated liquid film layer, the spray nozzle 3 stops and the circulating member 2 rotates by ten revolutions (in the present specification, hereinafter referred to as "idling") . The idling makes it possible to promote the drying of the coated liquid film. Thereafter, the liquid is again applied from the spray nozzle 3, to thereby form a second coated liquid film layer.

FIG. 3 is a flowchart showing the procedure of a liquid applying and drying method according to the second embodiment. The same processes as those in the first embodiment shown in FIG. 2 are denoted by identical reference symbols, and the description will be omitted. Hereinafter, only different points will be described.

After starting to apply the liquid in Step S5, it is determined whether a first predetermined number of revolutions of the circulating member 2^' have been completed, or not (Step S21) . The first predetermined number of revolutions corresponds to the number of coated film layers, which are continuously applied. That is, in the case where idling is executed after the one liquid film layer has been applied, the first predetermined number of times is one. In the case where idling is executed after the two liquid film layers have been applied, the first predetermined number of times is two. For example, in the case where idling is conducted every time a layer of the liquid film is applied, when the circulating member 2 rotates by one revolution, the application of the liquid has been completed (Step S7) .

In Step S22, it is determined whether the circulating member 2 has performed a second predetermined number of revolutions, or not. The second predetermined number of revolutions is the number of idling of the circulating member 2. That is, in the case where five revolutions of idling are conducted, the second predetermined number of revolutions is five, and in the case where ten revolutions of idling are conducted, the second * predetermined number of revolutions is ten. When the number of revolutions of idling of the circulating member 2 reaches the second predetermined number of revolutions, the procedure is advanced to Step S23. In Step S23, it is determined whether a third predetermined number of revolutions of the circulating member 2 have been completed, or not. The third predetermined number of revolutions is provided in order to determine whether a coated film having a desired number of superposed layers has been formed, or not. In this embodiment, the third predetermined number of revolutions is obtained by multiplying a number of repetitions of Steps S5 to S23 necessary to form the coated film having the desired number of superposed layers by a sum of the first predetermined number of revolutions and the second predetermined number of revolutions. For example, in the case where five revolutions of idling are conducted every time one layer is applied, in order to apply five superposed layers, the third predetermined number of revolutions is 30, because of 5 * (1 + 5) = 30. It is needless to say that the operation may be changed so that the number of repetitions of Steps S5 to S23 is inputted to obtain a desired number of superposed layers.

When the third number of revolutions of the circulating member 2 have not yet been completed (Step S23) , the procedure is returned to Step S5, and the processes of Steps S5 to S23 are repeated. When the third predetermined number of revolutions have been completed, the procedure is advanced to Step S8, and hereinafter the liquid applying and drying process is completed in the same manner as that in the first embodiment .

According to the second embodiment, with the idling of the circulating member, it is possible to promote the drying of the liquid. (Third Embodiment) (Traverse)

FIG. 4 is a plan view showing a liquid applying and drying device according to a third embodiment. The same structural elements as those in the first embodiment shown in FIG. 1 are denoted by identical reference symbols, and the description will be omitted. The spray nozzle 3 is fitted to a support bar 22 so as to move in directions indicated by an arrow X. The directions indicated by the arrow X are along the axial direction of the circulating member 2. In the present specification, the movement of the spray nozzle 3 in the directions indicated by the arrow X is called "traverse".

Hereinafter, a description will be given of the liquid applying and drying method according to the third embodiment.

FIG. 5 is a flowchart showing the procedure of the liquid applying and drying method according to the third embodiment. The same processes as those in the first embodiment shown in FIG. 2 are denoted by identical reference symbols, and the description will be omitted. Hereinafter, only differences will be described.

After the application of the liquid starts in Step S5 or simultaneously with the application, the traverse movement of the spray nozzle 3 is started. The traverse movement of the spray nozzle 3 is favorable in a case where a spray nozzle having a narrower pattern width with respect to the substrate P having a larger width is employed to the application. After the predetermined number of revolutions of the circulating member 2 has been completed (Step S6) , the traverse movement of the spray nozzle 3 is completed (Step S32) . The procedure is advanced to Step S7, the application of the liquid is completed, and the liquid applying and drying process is completed in the same manner as that of the first embodiment. The traverse distance may be a distance between one end and the other end of the substrate P, or may correspond to a desired applied area width. Also, the liquid may be applied in only a forward route of the traverse movement of the spray nozzle 3, or the liquid may be applied in both of the forward route and the backward route.

(Fourth Embodiment)

In the third embodiment, the spray nozzle 3 is continuously subjected to a traverse movement in association with the rotation of the circulating member. On the contrary, in a fourth embodiment, the spray nozzle 3 is intermittently subjected to the traverse movement every the fourth predetermined number of revolutions . ^' Hereinafter, the liquid applying and drying method according to the fourth embodiment will be described.

FIG. 6 is a flowchart showing the procedure of a method of applying and drying a liquid according to the fourth embodiment. The same processes as those in the first embodiment shown in FIG. 2 are denoted by-- identical reference symbols, and the description will be omitted. Hereinafter, only the differences will be described.

After the application of the liquid starts in Step S5, the application of the liquid is completed at a predetermined timing (Step S41) . The predetermined timing can be arbitrarily set. In the fourth embodiment, the predetermined timing is a timing immediately before the circulating member 2 rotates by one revolution. In Step S42, it is determined whether the circulating member 2 has performed a fourth predetermined number of revolutions, or not. The fourth predetermined number of revolutions is the number of revolutions of the circulating member that rotates between the traverses of the spray nozzle 3. The fourth predetermined number of revolutions can be arbitrarily set as the occasion demands. In the case where the fourth predetermined number of revolutions is set to two or more, the procedure is returned to Step S5. In this embodiment, . since the fourth predetermined number of revolutions is set to one, the procedure is advanced to Step S43.

In Step S43, the rotation of the circulating member 2 stops. Then, in Step S44, it is determined whether the predetermined number of revolutions of the circulating member 2 has been completed, or not. The predetermined number of revolutions is set on the basis of the number of traverse, or the number of superposed layers of the coated films. In the case where the predetermined number of revolutions has not yet been completed, the spray nozzle 3 conducts the traverse movement by a predetermined distance D (Step S45) . Then, the procedure is returned to Step S4, the rotation of the circulating member 2 starts, and the processes of Steps S4 to S45 are repeated until the predetermined number of revolutions has been completed. When the predetermined number of revolutions of the circulating member 2 has been completed (Step S44), the procedure is advanced to Step S9, the air blowing stops, and subsequently the liquid applying and drying process is completed as in the first embodiment. In the fourth embodiment shown in FIG. 6, the rotation of the circulating member 2 stops once when the spray nozzle 3 conducts the traverse movement by the predetermined distance D. However, the present invention is not limited to the above-mentioned configuration, and Step S43 may be omitted. In this case, after the spray nozzle 3 has conducted the traverse movement by the predetermined distance D in Step S45, the procedure is advanced to Step S5 and the application of the liquid starts. Also, when the predetermined number of revolutions of the circulating member 2 has been completed (Step S44), the procedure is advanced to Step S9 after the rotation of the circulating member has stopped.

FIGS. 7A to 7E are schematic diagrams showing the coated films that are applied through the liquid applying and drying method according to the fourth embodiment .

FIGS. 7A and 7B schematically shows a coated film M in the case where the predetermined distance D by which the spray nozzle 3 conducts the traverse movement is substantially equal to the pattern width W of the spray nozzle 3. FIG. 7A is a plan view showing the substrate P developed for. explanation, and FIG. 7B is a side view thereof. The coated film M is evenly applied to the substrate P.

FIGS. 7C and 7D schematically show the coated film M in the case where the predetermined distance D by which the spray nozzle 3 conducts the 'traverse movement is smaller than the pattern width W of the spray nozzle 3. FIG. 7C is a plan view showing the substrate P developed for explanation, and FIG. 7D is a side view thereof. Similarly, in this case, it is understood that the coated film M is evenly applied to the substrate P.

Similarly, in the fourth embodiment, the coated films can be applied and superposed. FIG. 7E shows the coated film M2 of a second layer, which is applied to the coated film Ml of the first layer. In the case where the coated films are applied and superposed, the coated film Ml of the first layer and the coated film M2 of the second layer can be offset by the distance E. The coated films are thus applied, thereby making it possible to more evenly apply the coated films. (Fifth Embodiment)

(Intermittent Application)

The spray nozzle 3 according to the present invention can be so controlled as to conduct not only the continuous application but also the intermittent application. The liquid is intermittently applied, thereby making it possible to form an application pattern with intervals in the circumferential direction.

In addition, the above application pattern is combined with the above traverse, to thereby making it possible to obtain application patterns shown in FIGS. 8A to 8C.

The application pattern shown in FIG. 8A is obtained by the intermittent application in which the spray nozzle 3 stops for a time T and the traverse movement of the spray nozzle 3 is conducted by the predetermined distance D. The intermittent application is conducted along the rotating direction A by the spray nozzle 3 having the pattern width W. When the circulating member 2 rotates by one revolution, the spray nozzle 3 conducts the traverse movement by the predetermined distance D in the direction indicated by the arrow X. The spray nozzle 3 conducts the intermittent application along the rotating direction A. Thus, the intermittent application and the traverse movement are combined together, thereby making it possible to obtain the application pattern shown in FIG. 8A.

The application pattern shown in FIG. 8B is obtained by superposed-layer application by the traverse movements of two predetermined distances D and Dl. That is, the intermittent application in which the spray nozzle 3 stops for the time T is conducted along the rotating direction A by the spray nozzle 3 having the pattern width W. When the circulating member 2 rotates by one revolution, the spray nozzle 3 conducts the traverse movement by the predetermined distance D in the direction indicated by the arrow X. The spray nozzle 3 conducts the intermittent application along the rotating direction A. After the intermittent application and the traverse movement of the predetermined distance D are repeated by a predetermined number of times, the spray nozzle 3 conducts the traverse movement by the predetermined distance Dl in the direction indicated by the arrow X. Then, the above process is repeated, thereby making it possible to obtain the application pattern shown in FIG. 8B. The predetermined distance Dl is larger than the predetermined distance D and larger than the pattern width W. The application pattern shown in FIG. 8C is obtained by intermittently stopping the rotation of the circulating member and spraying while the spray nozzle 3 conducts the traverse movement in the direction indicated by the arrow X when the rotation is stopped, as disclosed in Japanese Patent Application Laid-open No. 2004-351413. In the traverse movement, application is conducted while an unapplied portion is provided by stopping the spray for the time Tl. After the completion of the traverse movement, the circulating member 2 is rotationally moved by a predetermined distance S by the pitch of the spray, and application is conducted while conducting the traverse movement in the same manner as that described above. Subsequently, the traverse movement is repeated by a predetermined number of times, and when the application pattern M reaches a desired length L, application is conducted while the traverse movement is again conducted after an intermittent rotation is conducted for a time T2. After the circulating member rotates by one revolution while being dried, offset is effected to repeat the applying work. The application and drying can be conducted until a desired superposed layer state is obtained. The spray can be conducted in an application width Wl in a pulse manner.

In the case where the application patterns shown in FIGS. 8A, 8B, and 8C are obtained, the masking sheet is placed on the substrate P, thereby making it possible to apply a more precise pattern. (Sixth Embodiment) (Slot Nozzle) In the first embodiment to the fifth embodiment, the spray nozzle 3 is used as a liquid applying device. However, the present invention is not limited to the spray nozzle, and is capable of using a slot nozzle. The use of the slot nozzle makes it possible to more simply form the application pattern shown in FIG. 8A.

FIG. 9 is a schematic structural diagram showing a liquid applying and drying device 31 according to a sixth embodiment. FIG. 10 is a plan view showing the liquid applying and drying device 31 according to the sixth embodiment. FIGS. HA and HB are schematic structural diagrams showing a slot nozzle 33.

In FIG. 9, the same configurations as those in the first embodiment shown in FIG. 1 are denoted by identical reference symbols, and the description will be omitted. The circulating member 2 rotates in a direction indicated, by an arrow B. The substrate P is placed on the circulating member 2. The slot nozzle 33 is in contact with the substrate P.

As shown in FIG. HA, the slot nozzle 33 is equipped with a passage 34 through which a liquid passes, a shim 35, and a transverse groove 36. As shown in FIG. HB, the shim 35 has a plurality of cutout portions 35a. The passage 34 communicates with the plurality of cutout portions 35a through the transverse groove 36. The liquid flows into the plurality of cutout portions 35a through the transverse groove 36 from the passage 34, and is discharged from the slot nozzle 33 as indicated by arrows C.

With the above-mentioned .configuration, as shown in FIG. 10, a plurality of application patterns M can be formed. When the slot nozzle 33 is intermittently operated, the application pattern shown in FIG. 8A can be readily formed.

In the case of the superposed-layer application, the circulating member 2 is rotated by a plurality of times, and the liquid is sequentially applied onto the coated film. The drying of the coated film may be promoted by conducting idling as described above.

The present invention uses a vacuum suction drum to suck the substrate P onto the circulating member 2. However, the present invention is not limited to this configuration, and the substrate P can be fixed to the circulating member 2 by means of a fastening band or a fitting claw.

According to the present invention, for example, in the flowcharts shown in FIGS. 2, 3, 5, and 6, after an air blowing starts (Step S3) , and the rotation of the circulating member starts (Step S4) , a substrate heating process for heating the substrate with a heated air from the air blower may be provided before the liquid application starts (Step S5) . With this configuration, it is possible to promote the drying of the liquid. In the above embodiment, the description is provided of only one nozzle, however, the present invention is not limited to this configuration, and is capable of using a plurality of nozzles. For example, when a plurality of spray nozzles are arranged along the rotating direction of the circulating member, the superposed-layer application can be conducted with one revolution. Also, when the plurality of spray nozzles are arranged along the axial direction of the circulating member, it is possible to reduce the number of traverse movements.

Also, it is possible to combine the slot nozzle and the spray nozzle together. In this case, the spray nozzle may be disposed downstream of the slot nozzle. This is because the spray nozzle is of a non-contact type whereas the slot nozzle is of a contact type.

According to the method of the present invention, when the electrode ink is applied to an electrolyte membrane, it is possible to form a membrane electrode assembly (MEA) for a fuel cell. The method of the present invention is particularly suitable for the formation of the MEA for a polyelectrolyte membrane fuel cell (PEFC) and a direct methanol fuel cell (DMFC) . The present invention is not limited to the above-mentioned embodiments, but can be implemented in various other configurations without deviating from the features of the invention. For that reason, the above- mentioned embodiments are merely exemplified in every respect, and should not be definitely interpreted. The scope of the present invention is shown by the claims, and is not limited by the description of the specification. In addition, all of modifications and changes which belong to the equivalent scopes of the claims fall within the scope of the present invention.

For example, the liquid application in the present invention may be the atomizing application or the liquid film application. The atomizing application may employ an airless spray, an air spray, a centrifugal atomization, an ultrasonic wave, a bubbler, an ink jet, or the combination thereof. As the spray system, there may be applied a control coat method that is disclosed in Japanese Patent Application Laid-open No. H08-501974 or Japanese Patent Application Laid-open No. HOβ-170308.

As the liquid film application, a roll coat, a screen coat, a reverse coat, a slot nozzle coat, or the combination thereof may be used. Also, the spray nozzle according to the present invention may be of the type that transforms the liquid into particles, or type that applies the liquid in the form of a film. As the type that transforms the liquid into the particles, there, may be used a so-called screen spray system in which a liquid that is once filled in pores of the through-hole type porous sheet is pressurized by a liquefied gas into fine particles, transferred to a web 7, and application is performed, as disclosed in Japanese Patent Application Laid-open No. 6-86956 filed by the present applicant, Nordson KK, which is incorporated in Japan. The slot nozzle may be of the type that discharges the liquid in a predetermined pattern in the form of a liquid film. ^'

This application claims the benefit of Japanese Patent Application No. 2006-014998, filed January 24, 2006, which is hereby incorporated by reference herein in its entirety.

Claims

1. A method of applying and drying a liquid, comprising: a placement step of placing a sheet substrate on a circulating member; an application step of moving the circulating member and applying a liquid on the substrate; and a rotation dry step of rotating the circulating member through a plurality of revolutions to dry the liquid.

2. A method of applying and drying a liquid, comprising: a placement step of placing a sheet substrate on a circulating member; an application step of moving the circulating member and applying a liquid on the substrate by at least one applying device; a dry step of promoting drying of the liquid; and a multilayer coating application step of applying a plurality of layer coatings by repeating said application step and said dry step.

3. A method of applying and drying a liquid according to Claim 1 or 2, further comprising a dry step of drying the liquid applied on the substrate by at least one of cold air, warm air, hot air, radiation heat, and heat transmission of heating means of the circulating member.

4. A method of applying and drying a liquid according to any one of Claims 1 to 3, wherein said placement step includes a suction step of sucking the substrate on the circulating member with vacuum.

5. A method of applying and drying a liquid according to any one of Claims 1 to 4, further comprising a substrate heating step of heating the substrate before said application step. '

6. A method of applying and drying a liquid according to any one of Claims 1 to 5, wherein said placement step includes a step of placing an air- permeability member between the circulating member and the substrate.

7. A method of applying and drying a liquid according to any one of Claims 1 to 6, wherein said placement step includes a step of placing a masking member on the substrate.

8. A method of applying and drying a liquid according to any one of _^Claims 1 to 7, wherein the liquid comprises an electrode ink.

9. A method of applying and drying a liquid according to any one of Claims 1 to, 8, wherein the substrate comprises an electrolyte membrane.

10. A method of applying and drying a liquid according to any one of Claims 1 to 9, wherein said application step includes a dispensing application step of dispensing the liquid from a slot nozzle to apply the liquid onto the substrate.

11. A method of applying and drying a liquid according to any one of Claims 1 to 9, wherein said application step includes a spray application step of spraying the liquid from a spray nozzle to apply the liquid onto the substrate.

12. A method of applying and drying a liquid according to Claim 2, wherein said multilayer coating application step includes a dispensing application step of dispensing the liquid from a slot nozzle to apply the liquid onto the substrate, and a spray application step of spraying the liquid from a spray nozzle to apply the liquid onto the substrate.

13. A method of applying and drying a liquid according to Claim 11 or 12, wherein said spray application step includes a step of moving the spray nozzle in a traverse direction when each application in one revolution of the circulating member is ended.

14. A method of applying and drying a liquid according to Claim 11 or 12, wherein said spray application step includes a step of rotating the circulating member through one or more revolutions between a spray application and a spray application.

15. A method of applying and drying a liquid according to Claim 10 or 12, wherein said dispensing application step includes a step of operating one slot nozzle intermittently to apply the liquid onto a plurality of application areas.

16. A method of applying and drying a liquid according to Claim 10, 12, or 15, wherein said dispensing application step includes a step of rotating the circulating member through one or more revolutions between a dispensing application and a dispensing application.

17. A method of forming a membrane electrode assembly, comprising applying an electrode ink to an electrolyte membrane by using a method of applying and drying a liquid according to any one of Claims 1 to 16 to form a membrane electrode assembly.

18. A method of manufacturing a polyelectrolyte membrane fuel cell or a direct methanol fuel cell, which uses a membrane electrode assembly formed by a method of forming a membrane electrode assembly according to Claim 17.