JP2023033807A - Manufacturing method of gasket - Google Patents

Abstract

To provide a manufacturing method of a gasket which can equalize a thickness of the gasket.SOLUTION: A manufacturing method of a gasket has: a first process for forming a first thin-thickness layer 211 on a base material by screen-printing by using a first screen plate 510; a second process for progressing bridging by heating the first thin-thickness layer 211 after the first process; and a third process for forming a second thin-thickness layer 212 so as to cover the first thin-thickness layer 211 on the base material by the screen-printing by using a second screen plate 520 after the second process. A thickness of a second support part 522 of the second screen plate 520 is equal to or thinner than a thickness of a region at which a thickness at the vicinity of both sides of the first thin-thickness layer 211 in a width direction is the thickest, and a width W2 of the second support part 522 between opposing faces is equal to or wider than a width of the first thin-thickness layer 211.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method of manufacturing a gasket.

BACKGROUND ART Conventionally, there has been known a method of manufacturing a gasket having a flat surface by screen printing on a base material such as a separator provided in a fuel cell. In screen printing, it is known that a phenomenon (called a saddle phenomenon) occurs in which the thickness in the center in the width direction is thin and the thickness in the vicinity of both sides in the width direction is thick. If such a phenomenon occurs, there is a risk that the sealing performance will deteriorate.

JP-A-6-349663 JP-A-8-264374 JP 2020-138514 A Japanese Patent Application Laid-Open No. 2021-32372

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a gasket that can uniformize the thickness of the gasket.

The present invention employs the following means to solve the above problems.

That is, the method for manufacturing the gasket of the present invention includes:
Using a first screen plate having a first support portion that is in contact with the surface of the base material and provided along both sides of the region where the gasket is to be formed, and a first screen that is supported on the first support portion , a first step of forming a first thin film layer on the substrate by screen printing;
After the first step, a second step of heating the first thin film layer to promote cross-linking;
After the second step, a second supporting portion arranged along both sides of the first thin film layer and in contact with the substrate surface, and a second screen supported on the second supporting portion. a third step of forming a second thin film layer on the substrate by screen printing using a two-screen plate so as to cover the first thin film layer;
The thickness of the second supporting portion is equal to or less than the thickness of the thickest portions near both sides in the width direction of the first thin film layer, and the width between the facing surfaces of the second supporting portions provided on both sides of the first thin film layer is It is characterized by being equal to or larger than the width of the first thin film layer.

According to the present invention, in the first thin film layer, a phenomenon occurs in which the thickness in the center in the width direction is thin and the thickness in the vicinity of both sides in the width direction is thick. However, after the shape of the first thin film layer is stabilized by the second step, the second thin film layer is formed by the third step so as to cover the first thin film layer using the second screen plate configured as described above. be done. As a result, both sides of the thin central portion in the width direction of the first thin film layer and the thick portions near both sides in the width direction of the first thin film layer are covered with the second thin film layer.

In the second step, the cross-linking of the first thin film layer is preferably allowed to progress to such an extent that the first thin film layer is not completely cured and the shape of the first thin film layer is not deformed.

The thickness of the second supporting portion is preferably set to be 0.01 mm or more thinner than the thickest portions near both sides in the width direction of the first thin film layer.

Also, the width between the facing surfaces of the second supporting portions provided on both sides of the first thin film layer is preferably set to be wider than the width of the first thin film layer by 0.05 mm or more.

In addition, each of the above configurations can be employed in combination as much as possible.

As explained above, according to the present invention, the thickness of the gasket can be made uniform.

FIG. 1 is a cross-sectional view of a sealing structure according to an embodiment of the invention. FIG. 2 is a plan view of a gasket according to an embodiment of the invention. FIG. 3 is a manufacturing process diagram of a method for manufacturing a gasket according to an embodiment of the present invention. FIG. 4 is a manufacturing process diagram of a method for manufacturing a gasket according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION A mode for carrying out the present invention will be exemplarily described in detail below based on an embodiment with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to them, unless otherwise specified. .

(Example)
A method of manufacturing a gasket according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. In this embodiment, a case where a gasket is provided on a separator as a base material in a fuel cell will be described.

<Sealed structure>
A sealing structure according to this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view of a sealing structure according to an embodiment of the present invention, and more specifically, shows a part of a cross-sectional view of a fuel cell. The fuel cell 10 is constructed as a cell stack consisting of a plurality of single cells. A single cell is composed of an MEA (Membrane Electrode Assembly) 100 and a pair of separators 200 provided on both sides of the MEA 100, respectively. The MEA 100 comprises an electrolyte membrane 110 and a pair of gas diffusion layers 120 provided on both sides of the electrolyte membrane 110 . Also, the separator 200 as a base material is a plate-shaped member made of metal, carbon material, or the like. The separator 200 is formed with a channel 201 through which a fuel gas, an oxidant gas, or the like flows.

Each unit cell is provided with a gasket 210 made of a rubber-like elastic material to prevent leakage of fuel gas, oxidant gas, and the like to the outside. Preferred examples of materials for the gasket 210 include silicone rubber (VMQ), fluororubber (FKM), EPDM, and butyl rubber. This gasket 210 seals the gap between the separator 200 and the electrolyte membrane 110 .

<Gasket>
Gasket 210 will be described in more detail with reference to FIGS. FIG. 2 is a plan view of a gasket 210 provided on a separator 200 according to an embodiment of the invention. A sectional view of the separator 200 and the gasket 210 in FIG. 1 corresponds to the AA sectional view in FIG.

The separator 200 is provided with a channel 201 formed on the surface of the separator 200 and a plurality of manifolds 202 . A manifold 202 is provided to distribute fuel gas, oxidant gas, coolant, etc. to each cell.

Gaskets 210 are formed integrally with the separator 200 around the area where the flow path 201 is formed and around the manifold 202 to prevent the fuel gas from leaking to the outside. is provided. That is, the gasket 210 is provided integrally with the separator 200 so as to surround the areas to be sealed (the area in which the flow path 201 is formed and the area in which the manifold 202 is provided). In addition, in FIG. 2, the portion where the gasket 210 is provided is indicated by a thick line. In this embodiment, gaskets 210 are provided on both sides of the separator 200, respectively.

<Manufacturing method of gasket>
Particularly, with reference to FIGS. 3 and 4, a method of manufacturing the gasket 210 according to this embodiment will be described. 3 and 4 are manufacturing process diagrams of a method for manufacturing a gasket according to an embodiment of the present invention, showing respective members in cross-sectional views.

The gasket 210 according to this embodiment is formed on the surface of the separator 200 by screen printing. Further, in the manufacturing method according to the present embodiment, a printing step (first step) by first screen printing, a heating step (second step), and a printing step (third step) by second screen printing. have The order of steps will be described below.

<<First step>>
FIG. 3 is an explanatory diagram of the first step. In the first step, screen printing is performed using the first screen plate 510 . The first screen plate 510 includes a first supporting portion (mask) 512 disposed so as to be in contact with the surface of the separator 200 which is a base material, and a mesh-like first screen 511 supported on the first supporting portion 512. It has The first support portions 512 are provided along both sides of the area where the gasket 210 is to be formed, which is indicated by a thick line in FIG. 2 . Also, the first support portion 512 is made of emulsion (hardened emulsion).

Using the first screen plate 510 configured as described above, the first thin film layer 211 is formed on the surface of the separator 200 by screen printing. In screen printing, first, the first screen plate 510 is arranged on the separator 200 so that the first supporting portion 512 is in contact with the surface of the separator 200 . In this state, the gasket material 250 is supplied to the surface side of the first screen plate 510 (the surface side of the first screen 511) (see FIG. 3(a)). Then, the squeegee 600 moves so as to slide on the surface of the first screen 511 while being pressed toward the separator 200 (moves rightward in the drawing).

As a result, part of the gasket material 250 pushed by the squeegee 600 passes through the mesh-like first screen 511 and is pushed out onto the surface of the separator 200 (see FIG. 3B). By moving the tip of the squeegee 600 from one side to the other side of the first support portions 512 provided on both sides of the region where the gasket 210 is to be formed, the first support portions 512 on one side and the first support portions 512 on the other side move. The gasket material 250 is embedded in the entire region between the facing surfaces of the support portion 512 . After that, the first screen plate 510 is removed to form the first thin film layer 211 on the surface of the separator 200 (see FIG. 3(c)).

Due to the so-called saddle phenomenon, the first thin film layer 211 formed as described above is thin in the center in the lateral direction (width direction) and thick in the vicinity of both sides in the width direction. For convenience, the thickness of the thickest portion near both sides in the width direction of the first thin film layer 211 is assumed to be H11, and the thickness of the central flat portion of the first thin film layer 211 is assumed to be H12. W1 is the maximum width of the first thin film layer 211 (the width of the portion in contact with the surface of the separator 200).

<<Second step>>
After the first thin film layer 211 is formed by the first step, the first thin film layer 211 is heated. Various known techniques can be applied to the heating method. This heating causes the first thin film layer 211 to crosslink. However, in this heating step, it is desirable that the first thin film layer 211 is cross-linked to such an extent that the shape of the first thin film layer does not collapse, rather than completely curing the first thin film layer 211 . This stabilizes the shape of the first thin film layer 211 .

<<Third step>>
FIG. 4 is an explanatory diagram of the third step. In the third step, screen printing is performed using the second screen plate 520 . The second screen plate 520 is supported on second supports (masks) 522 arranged along both sides of the first thin film layer 211 and in contact with the surface of the separator 200 , and on the second supports 522 . and a mesh-like second screen 521 . The second support portion 522 is also provided along both sides of the area where the gasket 210 is to be formed, which is indicated by the thick line in FIG. 2 . The second support portion 522 is also made of emulsion (hardened emulsion).

Using the second screen plate 520 configured in this way, the second thin film layer 212 is formed on the surface of the separator 200 by screen printing so as to cover the first thin film layer 211 . In the screen printing, first, the second screen plate 520 is arranged on the separator 200 so that the second supporting portions 522 are in contact with the surface of the separator 200 on both sides of the first thin film layer 211 . In this state, the gasket material 250 is supplied to the surface side of the second screen plate 520 (the surface side of the second screen 521) (see FIG. 4(a)). Then, the squeegee 600 slides on the surface of the second screen 521 while being pressed toward the separator 200 (moves rightward in the drawing).

As a result, part of the gasket material 250 pushed by the squeegee 600 passes through the mesh-like second screen 521 and is pushed out toward the surface of the first thin film layer 211 (see FIG. 4B). By moving the tip of the squeegee 600 from one side to the other side of the second supporting portions 522 provided on both sides of the first thin film layer 211, the second supporting portions 522 on one side and the second supporting portions 522 on the other side are moved. The gasket material 250 is embedded in the area between the facing surfaces of the portion 522 excluding the first thin film layer 211 . After that, by removing the second screen plate 520, the second thin film layer 212 is formed so as to cover the first thin film layer 211 (see FIG. 4(c)).

Here, the thickness H20 of the second supporting portion 522 of the second screen plate 520 is set to be equal to or less than the thickness H11 in the vicinity of both sides of the first thin film layer 211 in the width direction. In addition, the width W2 between the facing surfaces of the second support portions 522 provided on both sides of the first thin film layer 211 is set to be equal to or greater than the width W1 of the first thin film layer 211. As shown in FIG.

The second thin film layer 212 is formed so as to cover the first thin film layer 211 using the second screen plate 520 configured as described above. As a result, the second thin film layer 212 covers both the thin central portion in the width direction of the first thin film layer 211 and the thick portions near both sides in the width direction of the first thin film layer 211 .

After the second thin film layer 212 is formed by the third step, the first thin film layer 211 and the second thin film layer 212 are heated. Various known techniques can be applied to the heating method. This heating cures the first thin film layer 211 and the second thin film layer 212 by cross-linking. In this heating step, the heating time is longer than the heating time in the second step so that the cross-linking of the first thin film layer 211 and the second thin film layer 212 progresses and the second thin film layer 212 is completely cured.

<Excellent points of the method for manufacturing a gasket according to the present embodiment>
According to the manufacturing method of the gasket 210 according to the present embodiment, the first thin film layer 211 is thin in the center in the width direction and thick in the vicinity of both sides in the width direction. However, after the shape of the first thin film layer 211 is stabilized by the second step, the second thin film layer 212 is formed so as to cover the first thin film layer 211 using the second screen plate 520 by the third step. The thickness H20 of the second supporting portion 522 of the second screen plate 520 is set to be equal to or less than the thickness H11 near both sides of the first thin film layer 211 in the width direction. In addition, the width W2 between the facing surfaces of the second support portions 522 provided on both sides of the first thin film layer 211 is set to be equal to or greater than the width W1 of the first thin film layer 211. As shown in FIG.

Therefore, the second thin film layer 212 is provided so as to cover the thin central portion of the first thin film layer 211 in the lateral direction. More specifically, the second thin film layer 212 is provided so as to fill a region between a pair of thick portions near both sides in the width direction of the first thin film layer 211 . As described above, in order to satisfy H20≦H11, the tip of the thick portion near both sides in the width direction of the first thin film layer 211 enters the mesh-like second screen 521 during screen printing. As a result, the amount of gasket material 250 supplied to this vicinity is small, and the amount of gasket material 250 supplied to the vicinity of the center is large.

Moreover, by satisfying W2≧W1, both sides of the thick portions near both sides in the width direction of the first thin film layer 211 are covered with the second thin film layer 212 . As described above, since H20≦H11 is satisfied, it is possible to prevent the thickness H31 near both sides in the width direction of the second thin film layer 212 from becoming thicker than H11.

As described above, the thickness of the gasket 210 composed of the first thin film layer 211 and the second thin film layer 212 can be made uniform. As shown in FIG. 4C, the thickness of the thickest portion near both sides in the width direction of the gasket 210 is H31, and the thickness of the central flat portion of the gasket 210 is H32.

Here, a case where a gasket with a width of 5 mm and a thickness of 0.1 mm is manufactured using silicone rubber (VMQ) using one screen printing as in the conventional case, and two screen printings as in the present embodiment The result of comparison with the case of manufacturing using printing will be described. In the comparative test, the thickness H20 of the second support portion 522 in the second screen plate 520 used for the second screen printing was set to be 0.01 mm thinner than the thickest portions near both ends of the first thin film layer 211. bottom. That is, it was set to H20=H11-0.01 mm. Also, the width W2 between the facing surfaces of the pair of second support portions 522 is set wider than the width W11 of the first thin film layer 211 by 0.2 mm. That is, it was set to W2=W1+0.2 mm.

As a result, the thickness difference between the thickest part and the center in the width direction (corresponding to (H11-H12) in FIG. 3(c)) in the gasket manufactured by the conventional manufacturing method, The thickness difference (corresponding to (H31-H32) in FIG. 4(c)) of the gasket 210 obtained by this manufacturing method could be reduced to about 20%. In the above comparative test, the case where H20=H11-0.01 mm and W2=W1+0.2 mm is shown. However, in the present invention, the dimension setting of H20 and W2 is not particularly limited. For example, it is preferable to set H20 to be 0.01 mm or more thinner than H11, and it is preferable to set W2 to be 0.05 mm or more wider than W1.

(others)
In the above embodiment, the case where the gasket is provided on the separator of the fuel cell has been described as an example. However, gaskets according to the present invention are not limited to such uses. For example, in metal gaskets, the present invention can be applied to the case where a rubber-like elastic gasket is provided on the surface of the metal gasket main body.

10 fuel cell 100 MEA
110 electrolyte membrane 120 gas diffusion layer 200 separator 201 channel 202 manifold 210 gasket 250 gasket material 510 first screen plate 511 first screen 512 first support 520 second screen plate 521 second screen 522 second support 600 squeegee

Claims (4)

Using a first screen plate having a first support portion that is in contact with the surface of the base material and provided along both sides of the region where the gasket is to be formed, and a first screen that is supported on the first support portion , a first step of forming a first thin film layer on the substrate by screen printing;
After the first step, a second step of heating the first thin film layer to promote cross-linking;
After the second step, a second supporting portion arranged along both sides of the first thin film layer and in contact with the substrate surface, and a second screen supported on the second supporting portion. a third step of forming a second thin film layer on the substrate by screen printing using a two-screen plate so as to cover the first thin film layer;
The thickness of the second supporting portion is equal to or less than the thickness of the thickest portions near both sides in the width direction of the first thin film layer, and the width between the facing surfaces of the second supporting portions provided on both sides of the first thin film layer is A method of manufacturing a gasket, wherein the width of the gasket is greater than or equal to that of the first thin film layer. 2. The method according to claim 1, wherein in the second step, the first thin film layer is crosslinked to such an extent that the first thin film layer is not completely cured and the shape of the first thin film layer is not deformed. Method for manufacturing gaskets. 3. The manufacturing of the gasket according to claim 1, wherein the thickness of the second supporting portion is set to be 0.01 mm or more thinner than the thickest portions near both sides in the width direction of the first thin film layer. Method. 4. The method according to claim 1, 2 or 3, wherein the width between the facing surfaces of the second supporting portions provided on both sides of the first thin film layer is set to be 0.05 mm or more wider than the width of the first thin film layer. A method for manufacturing the described gasket.

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