Gasket forming method, sealing method, gasket, composite body, and fuel cell

Abstract

The present invention is a gasket molding method for molding a gasket on a workpiece, the gasket molding method comprising, in the following order: an application step for applying an active energy ray-curable liquid having a structural viscosity ratio of 1.5-4.0 (inclusive) to the inside of a cavity of a molding die; a bonding step in which the molding die coated with the active energy ray-curable liquid is bonded to the workpiece; a curing step in which the applied active energy ray-curable liquid is cured by irradiation with active energy rays; and a release step for releasing the cured active energy ray-curable liquid from the molding die together with the workpiece, in which the coating step has an overlapping region of the coating trajectory. As a result, provided is a method for forming a gasket, which suppresses the mixing of air bubbles in the overlapping region of the coating trajectory.

Description

Technical Field

[0001] The invention relates to a gasket forming method, a sealing method, a gasket, a composite body and a fuel cell. Background Art

[0002] As an object for sealing two parts, a gasket is known. Such a gasket is usually formed by applying (discharging) a molding resin such as a thermoplastic resin on a substrate using a dispenser (see Patent Document 1). In addition, since the molded gasket is a closed shape such as a circle or a rectangle, the dispenser starts from the coating start point St and returns to the coating start point En (see Figure 7B ). However, in reality, in many cases, the coating end point En exists at a position beyond the coating start point St, so that the joint is not parallel to the height direction.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-015240 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the case of a gasket forming method using such a distributor, Fig. 7A As shown by the dotted line, the prescribed discharge amount is not reached from the coating start point St, but is reached in a gradually increasing manner. Moreover, as time passes, as shown in FIG. Fig. 7A As shown by the solid line, the liquid changes its coating shape due to its own viscosity, such as wetting and spreading, dripping, etc. At this time, the front end portion of the coating start point shrinks so that it has a rounded corner, thus forming a small gap between the surface of the forming mold.

[0008] Furthermore, when the dispenser returns to the original position of the closed trajectory and is about to reach the coating end point En, the dispenser rides on the preceding liquid, and the coating process ends. The gap formed between the front end portion and the forming mold is closed by the subsequent liquid riding on the preceding liquid. In addition, a gap is also formed between the preceding liquid and the subsequent liquid by riding. Therefore, these gaps remain in the gasket in the form of bubbles (refer to Figure 7B ).

[0009] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a gasket forming method, a sealing method, a gasket, a composite, and a fuel cell. The gasket forming method suppresses the mixing of bubbles into the overlapping area of ​​the coating track.

[0010] Means for solving problems

[0011] (1) One embodiment of the present invention is a gasket forming method, which forms a gasket on a workpiece, and the gasket forming method includes: a coating step, which coats an active energy ray-curable liquid having a structural viscosity ratio of 1.5 or more and 4.0 or less in a cavity of a forming mold; a bonding step, which bonds the forming mold coated with the active energy ray-curable liquid to the workpiece; a curing step, which cures the coated active energy ray-curable liquid by irradiation with active energy rays; and a demolding step, which peels the cured active energy ray-curable liquid and the workpiece from the forming mold, wherein the coating step has an overlapping area of ​​the coating track. The structural viscosity ratio is a value obtained by dividing the viscosity (Pa·s) at a shear rate of 1.0 (1 / s) by the viscosity (Pa·s) at a shear rate of 10.0 (1 / s).

[0012] (2) In the aspect of (1) above, the viscosity of the active energy ray-curable liquid at a shear rate of 1.0 (1 / s) at 25° C. may be 12 Pa·s or more and 100 Pa·s or less.

[0013] (3) In the embodiment of (1) or (2) above, the viscosity of the active energy ray-curable liquid at a shear rate of 10.0 (1 / s) at 25° C. may be 5 Pa·s or more and 70 Pa·s or less.

[0014] (4) In any one of the above aspects (1) to (3), the active energy ray-curable liquid may contain an oligomer having an acryloyl group, an acryloyl group-containing monomer, a photoradical initiator, and silica.

[0015] (5) In the aspect of (4) above, the average particle size of the silicon dioxide may be 15 nm or more and 8500 nm or less.

[0016] (6) In the aspect of (4) above, the content of the silicon dioxide may be 0.1% by mass or more and 50% by mass or less.

[0017] (7) In any one of the above aspects (1) to (6), the molding die may have a trapezoidal cavity.

[0018] (8) In any one of the above aspects (1) to (7), the coating step may be performed using a dispenser.

[0019] (9) In the aspect of (8) above, the relative moving speed of the dispenser in the coating step may be 1 mm / sec or more and 500 mm / sec or less.

[0020] (10) In any one of the above modes (1) to (9), the overlapping area of ​​the above coating tracks includes a coating start point and a coating end point.

[0021] (11) In any of the above modes (1) to (10), the overlapping area of ​​the above coating tracks may include an intersection between one track and the other track.

[0022] (12) In any one of the above modes (1) to (11), the cavity of the above-mentioned forming mold may be subjected to a water-repellent coating treatment.

[0023] (13) Another aspect of the present invention is a gasket obtained by any one of the aspects (1) to (12) above.

[0024] (14) Another aspect of the present invention is a composite body comprising a fuel cell component as a workpiece and a gasket obtained by any one of the aspects (1) to (12).

[0025] (15) Another embodiment of the present invention is a fuel cell comprising the composite of (14) above.

[0026] (16) In the fuel cell of the above-mentioned embodiment (14), the fuel cell component may be selected from a separator, an electrolyte membrane, a frame, and an electrolyte membrane / electrode assembly.

[0027] (17) Another method described in the present invention is a sealing method for sealing two workpieces against each other, the sealing method comprising: a forming step, in which a gasket is formed on a workpiece by a gasket forming method of any one of the above methods (1) to (12); and a crimping step, in which another workpiece is arranged on the gasket formed on the above workpiece, and the above workpiece is crimped onto the above workpiece.

[0028] Effects of the Invention

[0029] According to the present invention, it is possible to provide a gasket forming method that suppresses mixing of bubbles into the overlapping region of coating tracks, a sealing method, a gasket, a composite body, and a fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic plan view showing a workpiece on which a gasket is formed.

[0031] Figure 2A 1 is a flowchart showing a gasket forming method according to an embodiment of the present invention.

[0032] Figure 2B It is a working diagram showing the gasket forming method according to the embodiment of the present invention.

[0033] Figure 3 It is a schematic perspective view showing a forming mold.

[0034] Figure 4 It is a schematic cross-sectional view showing a fuel cell.

[0035] Figure 5 is a flow chart showing a sealing method for sealing two components to each other.

[0036] Fig. 6A This is a schematic diagram showing the behavior of an active energy ray-curable liquid after the start of coating in the gasket forming method according to the embodiment of the present invention.

[0037] Figure 6B This is a schematic diagram showing the state of the active energy ray-curable liquid in the overlapping region of the gasket forming method according to the embodiment of the present invention.

[0038] Fig. 7A This is a schematic diagram showing the behavior of an active energy ray-curable liquid after the start of coating in a conventional gasket forming method.

[0039] Figure 7B This is a schematic diagram showing the state of the active energy ray-curable liquid in the overlapping region in a conventional gasket forming method. DETAILED DESCRIPTION

[0040] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments of the present specification, the same components are denoted by the same reference numerals throughout.

[0041] First, before describing the gasket forming method according to the embodiment of the present invention, the workpiece 10 on which the gasket 30 is formed will be briefly described. Figure 1 It is a schematic plan view showing the workpiece 10 on which the gasket 30 is formed.

[0042] The workpiece 10 is one or the other part when two parts are assembled with each other via the gasket 30, and has a desired size and shape, and is made of metal such as iron, aluminum, stainless steel, magnesium, titanium, carbon, or resin such as polyvinyl chloride, polyethylene naphthalate, polyethylene terephthalate, polyethylene, polypropylene, and polycarbonate. It should be noted that the workpiece 10 of the present embodiment is a rectangular plate.

[0043] The workpiece 10 is formed with one or more openings 10a or one or more recesses 10b. The spacer 30 is formed around the openings 10a and recesses 10b. The workpiece 10 preferably has a flat surface on which the spacer 30 is formed, but may also have a gently inclined surface.

[0044] However, the workpiece 10 may not have the opening 10 a and the recess 10 b , but another member may have the opening 10 a and the recess 10 b .

[0045] Next, a gasket forming apparatus used in the gasket forming method according to the embodiment of the present invention will be briefly described.

[0046] The gasket forming device mainly includes a coating device, a laminating device, an XYZ axis driving device, an active energy ray irradiation device 60, a demolding device and a control device.

[0047] The coating device can apply liquid to the coating object, for example, as long as it is a device for coating methods such as a dispenser, spray, inkjet, screen printing, gravure printing, etc., wherein a dispenser, inkjet, screen printing, and a dispenser 50 are preferred. The coating device of the present embodiment is composed of a dispenser 50 that discharges liquid from a nozzle 51 to the coating object, a tank or syringe for storing liquid, and a pump for supplying liquid. It should be noted that a rotating mechanism that rotates the nozzle 51 around the Z axis can be arranged on the coating device. As the above-mentioned dispenser 50, for example, a Mohno method (single-axis eccentric screw rotation method), a volume extrusion method using a plunger, etc. can be cited, wherein, due to the small amount of bubble mixing, it is preferred to use a volume extrusion method using a plunger.

[0048] In the present invention, the shape of the discharge port of the nozzle 51 can be circular, triangular, quadrilateral, trapezoidal, etc. In addition, in the present invention, the opening diameter (passage diameter) of the discharge port of the nozzle 51 is not particularly limited as long as it is below the opening of the cavity 41, and is, for example, 0.1 to 20 mm, and more preferably 0.3 to 5 mm. It should be noted that the relative moving speed of the dispenser 50 in the coating step S1 described later is not particularly limited, and is, for example, 1 mm / sec to 500 mm / sec, preferably 10 mm / sec to 200 mm / sec, and particularly preferably 50 mm / sec to 150 mm / sec.

[0049] The laminating device may be a clamshell type laminating device composed of a fixed table holding one laminating object (forming mold 40), a movable table holding another laminating object (workpiece 10), and a flip driving unit that flips the movable table toward the fixed table and away from the fixed table. However, the structure of the laminating device is not limited to the clamshell type.

[0050] In addition, the laminating device also includes a CCD camera or other photographing device for photographing the laminating object, so that the position, tilt, etc. of the laminating object can be confirmed during laminating. Furthermore, the laminating device is also used as a demoulding device for separating the laminating object. However, the demoulding device and the laminating device can also be provided independently.

[0051] The XYZ axis driving device includes an X axis moving unit that moves the dispenser 50 in the left-right direction, a Y axis moving unit that moves the dispenser 50 in the front-back direction, and a Z axis moving unit that moves the dispenser 50 in the up-down direction. However, the XYZ axis driving device may be any combination as long as it can move the dispenser 50 relative to the coating object along the three-dimensional XYZ axis, for example, it may be composed of an XY table that holds the dispenser 50 and a Z table that holds the coating object.

[0052] The active energy ray irradiation device 60 irradiates light such as ultraviolet rays and electron beams, and is composed of a UV lamp or UV-LED as a linear light source or a planar surface light source. The active energy ray irradiation device 60 is movably or fixedly arranged relative to the coating object. However, the active energy ray irradiation device 60 can also be arranged behind the moving direction of the dispenser 50 to cure the liquid while applying the liquid.

[0053] The control device uniformly controls the coating device, the laminating device (demolding device), the XYZ-axis driving device, and the active energy ray irradiation device 60. For example, the discharge volume of the dispenser 50 is adjusted by controlling the rotation speed (rotation speed, rotation angle) of the pump, or the laminating load and the pressing amount are adjusted by controlling the rotation speed (rotation angle) of the flip driving unit, and load control or position control based on the movable table is performed, or the position control and speed control of the dispenser 50 are performed by driving each driving unit of the XYZ-axis driving device, or the irradiation output of the light source is adjusted by controlling the power supplied to the active energy ray irradiation device 60.

[0054] Next, a description will be given of a gasket forming method for forming the gasket 30 on the workpiece 10 using the active energy ray-curable liquid 20 .

[0055] FIG. 2 shows a gasket forming method according to an embodiment of the present invention. Figure 2A It is a flow chart. Figure 2B It is a working diagram.

[0056] The active energy ray-curable liquid 20 is an ultraviolet-curable resin that is cured by reaction when irradiated with active energy rays (eg, ultraviolet rays), and may be, for example, a (meth)acrylate composition that undergoes radical polymerization or an epoxy composition that undergoes cation polymerization.

[0057] It should be noted that, in the present invention, "liquid" means liquid at 25°C. In addition, the viscosity of the active energy ray-curable liquid 20 at a shear rate of 1.0 (1 / s) at 25°C is not particularly limited, for example, it is 500 Pa·s or less, preferably 0.01 Pa·s or more and 400 Pa·s or less, more preferably 0.1 Pa·s or more and 350 Pa·s or less, and particularly preferably 12 Pa·s or more and 100 Pa·s or less. In addition, the viscosity at a shear rate of 10.0 (1 / s) is, for example, 5 Pa·s or more and 70 Pa·s or less, preferably 7 Pa·s or more and 35 Pa·s or less. In addition, the structural viscosity ratio of the active energy ray-curable liquid 20 at 25°C is not particularly limited, for example, it is 1.0 or more and 10 or less, preferably 1.1 or more and 8 or less, more preferably 1.3 or more and 7 or less, and particularly preferably 1.5 or more and 4 or less. By making the above viscosity or structural viscosity ratio within the above range, it is more suitable for the gasket forming method of the present invention. The above-mentioned viscosity and structural viscosity ratio can be obtained using a rheometer. It should be noted that in this specification, viscosity refers to the complex viscosity obtained using a rheometer.

[0058] Here, the structural viscosity ratio is the value obtained by dividing the viscosity (Pa·s) at a shear rate of 1.0 (1 / s) by the viscosity (Pa·s) at a shear rate of 10.0 (1 / s). In other words, the structural viscosity ratio is the shear stress (N / m 2 ) divided by the shear stress (N / m) at a shear rate of 10.0 (1 / s) 2 ) and obtain the value.

[0059] As the above-mentioned (meth)acrylate composition for free radical polymerization, for example, there can be mentioned a composition comprising a (meth)acryloyl group-containing oligomer, a (meth)acryloyl group-containing monomer, and a photoradical initiator. It should be noted that in this specification, the (meth)acryloyl group-containing oligomer refers to an oligomer having one or more (meth)acryloyl groups and a weight average molecular weight of 1000 or more. The (meth)acryloyl group-containing oligomer is not particularly limited, and examples thereof include urethane (meth)acrylates having a polycarbonate skeleton, urethane (meth)acrylates having a polyether skeleton, urethane (meth)acrylates having a polyester skeleton, urethane (meth)acrylates having a castor oil skeleton, urethane (meth)acrylates having a polybutadiene skeleton, urethane (meth)acrylates having a hydrogenated polybutadiene skeleton, polyisobutylene (meth)acrylates, silicone (meth)acrylates, isoprene (meth)acrylates, hydrogenated isoprene (meth)acrylates, and (meth)acryloyl group-containing acrylic polymers. Among them, urethane (meth)acrylates having a polycarbonate skeleton, urethane (meth)acrylates having a polybutadiene skeleton, urethane (meth)acrylates having a hydrogenated polybutadiene skeleton, and polyisobutylene (meth)acrylates are preferred.The (meth)acryloyl group-containing monomer is not particularly limited, and examples thereof include ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl methacrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, butoxy (meth)acrylate, acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, isobornyl (meth)acrylate, and acryloyl morpholine are preferred. In addition, the above-mentioned photoradical initiator is not particularly limited, and examples thereof include acetophenone-based photoradical polymerization initiators, benzoin-based photoradical polymerization initiators, benzophenone-based photoradical polymerization initiators, thioxanthone-based photoradical polymerization initiators, acylphosphine oxide-based photoradical polymerization initiators, and titanocene-based photoradical polymerization initiators. In addition, the mixing ratio of the (meth)acrylate composition is not particularly limited, and examples thereof include a composition containing 0.1 to 1000 parts by mass of a (meth)acryloyl-containing monomer and 0.1 to 30 parts by mass of a photoradical initiator relative to 100 parts by mass of a (meth)acryloyl-containing oligomer.

[0060] As the epoxy composition for cationic polymerization, for example, a composition comprising a cationic polymerizable compound and a photocationic initiator can be cited. In addition, as the above-mentioned cationic polymerizable compound, there is no particular restriction, for example, epoxy resin, alicyclic epoxy resin, oxetane compound, vinyl ether compound, etc. can be cited. In addition, as the above-mentioned photocationic initiator, there is no particular restriction, for example, onium salts such as aromatic iodonium salts and aromatic sulfonium salts can be cited. In addition, the mixing ratio of the above-mentioned epoxy composition is not particularly limited, for example, a composition comprising 0.1 mass parts or more and 30 mass parts or less of a photocationic initiator relative to 100 mass parts of the cationic polymerizable compound can be cited.

[0061] A thixotropy-imparting agent may be contained in order to impart thixotropy to the active energy ray-curable liquid 20. The thixotropy-imparting agent is not particularly limited, and examples thereof include silica, amide wax, and hydrogenated castor oil, among which silica is preferred.

[0062] As the above-mentioned silica, hydrophilic silica, hydrophobic silica, etc. can be enumerated, preferably hydrophobic silica. As hydrophobic silica, silica treated with hydrophobicity by organochlorosilanes, silicone oil, hexamethyldisilazane, alkylsilane, etc. can be used, wherein, preferably silica treated with hydrophobicity by silicone oil, hexamethyldisilazane.

[0063] The content of silicon dioxide is not particularly limited, but is, for example, 0.1% by mass to 50% by mass, preferably 0.5% by mass to 40% by mass, and particularly preferably 1% by mass to 30% by mass.

[0064] Moreover, the average particle size of silicon dioxide is not particularly limited, for example, more than 15nm and less than 8500nm, more preferably more than 20nm and less than 8000nm, and particularly preferably more than 25nm and less than 7500nm. By making the active energy ray curable liquid 20 contain silicon dioxide as described above, the viscosity and structural viscosity ratio can be adjusted. The average particle size refers to the average particle size of primary particles measured by observation under an electron microscope.

[0065] Furthermore, the gasket forming method according to the embodiment of the present invention includes a coating step S1 , a laminating step S2 , a curing step S3 , and a demolding step S4 in sequence.

[0066] In the coating step S1, first, the active energy ray-curable liquid 20 is applied to the cavity 41 of the molding die 40 described later, for example, in a single stroke from the coating start point St to the coating end point En, while being coated into a desired gasket shape. At this time, the coating end point En may be selected so that the coating trajectory passes over the coating start point St and partially overlaps (has an overlapping area) (see Figure 6B ).

[0067] It should be noted that after the coating starts, the active energy ray-curable liquid 20 may slightly spread and move from the coating start point St to the upstream side due to its own viscosity (see Fig. 6A ), but sometimes it is attracted and moves to the downstream side, or sometimes it maintains its original position.

[0068] Here, the forming die 40 will be described. Figure 3 It is a schematic perspective view showing the forming die 40 .

[0069] The forming mold 40 is held on a fixed table of the laminating device and has a cavity 41 having a shape corresponding to the formed gasket 30. The cavity 41 is, for example, circular, elliptical, or rectangular, and the inside is formed as a platform portion 42. However, the cavity 41 may be a closed shape that does not overlap with other trajectories, such as a trajectory of a stroke, or a closed shape that overlaps with other trajectories, and any shape may be adopted.

[0070] In addition, the cavity 41 is formed in a shape whose cross section is substantially rectangular, substantially trapezoidal, substantially triangular (mountain-shaped), substantially semicircular, etc., which is the same as the desired cross-sectional shape of the gasket 30, wherein a substantially trapezoidal shape is preferred. The size of the cavity 41 is not particularly limited, and may be, for example, 1 to 20 mm in lateral width and 0.2 to 10 mm in depth. It should be noted that the cross section of the cavity 41 may be a cross section whose height is greater than its width, or vice versa, a cross section whose width is greater than its height.

[0071] The mold 40 is made of a transparent material through which light can pass, for example, one or more materials selected from polymethyl methacrylate, cycloolefin polymer, polycarbonate, and glass. The surface of the cavity 41 may be subjected to a surface treatment for improving mold release properties.

[0072] in addition, Fig. 6A 1 is a schematic diagram showing the behavior of the active energy ray-curable liquid 20 after the start of coating in the gasket forming method according to the embodiment of the present invention. Figure 6B This is a schematic diagram showing the state of the active energy ray-curable liquid 20 in the overlapping region of the gasket forming method according to the embodiment of the present invention.

[0073] return Figure 2A, continue the description of coating step S1.

[0074] In the coating step S1, the dispenser 50 may discharge an amount of 100% or more of the volume of the cavity 41, that is, a discharge amount per unit length of 100% or more of the volume per unit length, so that the active energy ray-curable liquid 20 slightly overflows from the cavity 41. It should be noted that the upper limit of the discharge amount may be approximately 110%.

[0075] In addition, at the coating start point St, the discharge amount from the distributor 50 decreases, gradually increases, and reaches a predetermined value. Therefore, just before the coating end point En, the discharge amount of the distributor 50 can be reduced so that the total discharge amount at each point in the overlapping area is equal to the discharge amount at other equilibrium points, so as to control the thickness of the gasket 30 to be uniform (refer to Figure 6B It should be noted that the coating step S1 is preferably completed within 5 to 60 seconds from the coating start point St to the coating end point En. Therefore, the discharge amount is controlled according to the moving speed of the dispenser 50, but the moving speed can also be controlled by making the discharge amount constant.

[0076] Next, in the bonding process S2, the fixed table of the bonding device holding the forming mold 40 coated with the active energy ray-curing liquid 20 and the movable table holding the workpiece 10 are flipped so that they face each other, and the forming mold 40 and the workpiece 10 are bonded via the uncured active energy ray-curing liquid 20.

[0077] At this time, the bonding is performed with a bonding load of less than 1 MPa. It should be noted that the bonding load can be performed by measuring the bonding pressure while performing pressure control, or by measuring the bonding amount (pressing amount) while performing position control. In this way, the gasket can be formed by bonding with a low load, thereby reducing the load on the workpiece.

[0078] Next, in the curing step S3, the active energy ray curing liquid 20 between the mold 40 and the workpiece 10 is cured by irradiating the active energy ray with the active energy ray irradiation device 60. The accumulated light intensity is preferably 1000 mJ / cm 2 Above and 10000mJ / cm 2 The peak illuminance of the active energy ray was set to 100 mW / cm 2 Above and 5000mW / cm 2 the following.

[0079] At this time, the active energy ray irradiation device 60 is disposed on the opposite side of the molding surface of the molding die 40 where the cavity 41 is formed, and the irradiated active energy ray passes through the transparent molding die 40 and reaches the active energy ray curable liquid 20. It should be noted that the curing shrinkage rate of the active energy ray curable liquid 20 is not particularly limited, and is preferably 10% or less, and more preferably 2% or more and 10% or less, for example.

[0080] In the demolding step S4, in the laminating device as a demolding device, the movable table is turned over so as to be separated from the fixed table, and the solidified active energy ray-curable liquid 20 (as the gasket 30) is peeled off from (the cavity 41 of) the forming mold 40 together with the workpiece 10. It should be noted that in order to facilitate the removal of the gasket 30 from the forming mold 40 after use, it is preferred to pre-coat a fluorine-based, silicone-based or other mold release agent in the cavity 41 of the forming mold 40 to perform a waterproof coating treatment.

[0081] Thereafter, the workpiece 10 is removed from the movable table, and the forming step S10 is completed, so that the workpiece 10 having the spacer 30 directly provided on the surface can be obtained.

[0082] Example

[0083] Here, experimental examples (Examples and Comparative Examples) in which the spacers 30 (design values: top 1.0 mm×bottom 2.7 mm×height 1.0 mm) were formed using active energy ray-curable liquids 20 having various viscosities and structural viscosity ratios will be described.

[0084] In the experimental example, the following six samples were used as the active energy ray-curable liquid 20 , and a mold having a trapezoidal cavity 41 was used as the molding mold 40 , and the spacer 30 was molded according to the above-mentioned molding method.

[0085] Then, the area including the coating start point St and the coating end point En of each formed gasket 30 was magnified 200 times using a multi-sensor non-contact three-dimensional measuring machine (OGP manufactured by QVI Corporation) to check whether bubbles were mixed in. The results are shown in Table 1.

[0086] <Measurement of Viscosity>

[0087] The viscosity (Pa·s) of each active energy ray-curable liquid 20 was measured at room temperature 25° C. and a shear rate of 1.0 (1 / s) using a rheometer HAAKE MARS3 manufactured by Thermo Fisher Scientific KK.

[0088] <Structural Viscosity Ratio>

[0089] The viscosity (Pa·s) of each active energy ray-curable liquid 20 was measured at 25° C. and shear rates of 1.0 (1 / s) and 10.0 (1 / s) using a rheometer HAAKE MARS3 manufactured by Thermo Fisher Scientific KK, and the structural viscosity ratio was determined based on the following formula.

[0090] Structural viscosity ratio = viscosity at 1.0 (1 / s) / viscosity at 10.0 (1 / s)

[0091] Example 1: Composition containing polyisobutylene acrylate as an oligomer having an acryloyl group, isononyl acrylate as an acryloyl group-containing monomer, a photoradical initiator, and silica (average particle size 40 nm) treated with 9% by mass of hexamethyldisilazane

[0092] Example 2: Composition containing polyisobutylene acrylate as an oligomer having an acryloyl group, isononyl acrylate as an acryloyl group-containing monomer, a photoradical initiator, and silica (average particle size 7000 nm) treated with 15% by mass of silicone oil

[0093] Example 3: Composition containing polyisobutylene acrylate as an oligomer having an acryloyl group, isononyl acrylate as an acryloyl group-containing monomer, a photoradical initiator, and silica (average particle size 30 nm) treated with 9% by mass of hexamethyldisilazane

[0094] Example 4: Composition containing polyisobutylene acrylate as an oligomer having an acryloyl group, isononyl acrylate as an acryloyl group-containing monomer, a photoradical initiator, and silica (average particle size 50 nm) treated with 9% by mass of silicone oil

[0095] Comparative Example 1: Composition containing polyisobutylene acrylate as an oligomer having an acryloyl group, isononyl acrylate as an acryloyl group-containing monomer, a photoradical initiator, and silica (average particle size 9000 nm) treated with 9% by mass of silicone oil

[0096] Comparative Example 2: Composition containing polyisobutylene acrylate as an oligomer having an acryloyl group, isononyl acrylate as an acryloyl group-containing monomer, a photoradical initiator, and silica (average particle size 12 nm) treated with 9% by mass of silicone oil

[0097] [Table 1]

[0098] Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Comparative Example 2 Viscosity 9.68 14.78 44.24 54.40 83.96 155 Structural viscosity ratio 1.0 1.8 1.7 2.8 3.7 4.3 Bubble mixing have none none none none have

[0099] As shown in Table 1, as shown in Comparative Examples 1 and 2, when the structural viscosity ratio is less than 1.5 or greater than 4, mixing of bubbles is confirmed. On the other hand, as shown in Examples 1 to 4, when the structural viscosity ratio of the active energy ray-curable liquid 20 is 1.5 or more and 4 or less, mixing of bubbles is not confirmed, which shows the usefulness of limiting the structural viscosity ratio of the active energy ray-curable liquid 20.

[0100] Finally, a description will be given of a case where the fuel cell component 101 is used as the workpiece 10 for forming the gasket 30 and the gasket forming method of the present embodiment is applied to a method for manufacturing the fuel cell 100 . Figure 4 1 is a schematic cross-sectional view showing the fuel cell 100 .

[0101] Examples of the fuel cell component 101 include a separator 101a, an electrolyte membrane 101d, a frame 101f, and an electrolyte membrane / electrode assembly 101e that constitute the fuel cell 100 (single cell) (see Figure 4 ), and gaskets 30 are formed on them.

[0102] Among them, it is preferable to form the gasket 30 on the spacer 101a made of aluminum, stainless steel, titanium, graphite, carbon, etc. Figure 4 In the figure, 101b is a fuel electrode, 101c is an air electrode, and 101g is a cooling water passage.

[0103] Moreover, the manufacturing method of the fuel cell 100 includes, in sequence: a coating step S1, which coats the active energy ray-curable liquid 20 in the cavity 41 of the forming mold 40; a bonding step S2, which bonds the forming mold 40 coated with the active energy ray-curable liquid 20 to the fuel cell component 101; a curing step S3, which cures the coated active energy ray-curable liquid 20 by irradiation with active energy rays; and a demolding step S4, which peels the cured active energy ray-curable liquid 20 together with the fuel cell component 101 from the forming mold 40.

[0104] Furthermore, a description will be given of a case where the gasket molding method of the present embodiment is applied to a sealing method for sealing between two members. Figure 5 is a flow chart showing a sealing method for sealing two components to each other.

[0105] The sealing method for sealing two components includes a forming step S10 of forming the gasket 30 on one component (for example, the workpiece 10 described above) and a crimping step S20 of crimping (press-bonding) one component to another component.

[0106] The forming step S10 is as described in the above-mentioned gasket forming method, and therefore the description thereof is omitted.

[0107] In the crimping step S20, another component is arranged on the gasket 30 formed on one component, and one component is crimped to the other component. In the crimping step S20, a crimping device such as the laminating device used in the laminating step S2 can be used, and position control and pressure control can also be performed. However, as long as the two components are fastened to each other with screws (bolts), screw fastening can be used, or the two components can be crimped to each other by riveting.

[0108] It should be noted that this sealing method can be applied not only to the above-mentioned fuel cell 100 but also to any relatively small component such as a main seal of a liquid crystal display panel.

[0109] However, in the coating process S1 of the above-mentioned embodiment, the overlapping area of ​​the coating track is formed by a closed track (seam) including the coating start point St and the coating end point En, but as a coating track that easily contains bubbles, there is also a coating track including an intersection point of a (previous) track and other (subsequent) tracks. In this case, control can be performed in the following manner: from just before the intersection with the preceding track, the discharge amount of the dispenser is gradually reduced, and it is set to a trace amount (or no discharge) at the intersection point (the middle point of the width of the track). After passing the intersection point, the discharge amount of the dispenser is gradually increased to reach a normal coating amount. When the structural viscosity ratio of the active energy ray-curable liquid 20 is greater than 1.5 and less than 4.0, the generation of bubbles can be suppressed even at such an intersection point.

[0110] As described above, the gasket forming method of the embodiment of the present invention is a gasket forming method for forming a gasket 30 on a workpiece 10, and sequentially includes: a coating step S1, which coats an active energy ray-curable liquid 20 having a structural viscosity ratio of greater than 1.5 and less than 4.0 into a cavity 41 of a forming mold 40; a bonding step S2, which bonds the forming mold 40 coated with the active energy ray-curable liquid 20 to the workpiece 10; a curing step S3, which cures the coated active energy ray-curable liquid 20 by irradiation with active energy rays; and a demolding step S4, which peels the cured active energy ray-curable liquid 20 off the forming mold 40 together with the workpiece 10, wherein the coating step S1 has an overlapping area of ​​the coating track.

[0111] Thus, the viscosity of the active energy ray-curable liquid 20 is optimized, and shape stability and compatibility with the preceding active energy ray-curable liquid 20 can be achieved. Therefore, in the overlapping area of ​​the coating track, the mixing of bubbles can be suppressed, and the thickness of the spacer 30 can be made uniform. Furthermore, the spacer 30 can be formed at a low pressure of 1 MPa or less using the active energy ray-curable liquid 20.

[0112] The active energy ray-curable liquid 20 of the embodiment has a viscosity of 12 Pa·s or more and 100 Pa·s or less at 25° C. Thus, in the molding of the spacer 30 having the overlapped region, mixing of bubbles can be further suppressed.

[0113] The molding die 40 of the embodiment has a trapezoidal cavity 41. Thus, a gasket 30 with excellent sealing properties can be molded. In particular, in the coating step S1, when the trapezoidal cavity 41 is filled with the active energy ray-curable liquid 20, a problem of bubbles being easily mixed in the molding of the gasket 30 having an overlapping area is likely to occur. In contrast, this problem can be solved by using the active energy ray-curable liquid 20 having a predetermined structural viscosity ratio as in the present embodiment.

[0114] The coating step S1 of the embodiment is performed using the dispenser 50. Thus, in the coating step S1, the discharge amount of the active energy ray-curable liquid 20 can be easily controlled. In addition, the position and speed control of the dispenser 50 can be simplified.

[0115] The overlapping area of ​​the coating tracks of the embodiment includes the coating start point St and the coating end point En. In addition, the overlapping area of ​​the coating tracks of the embodiment includes the intersection point between one track and other tracks.

[0116] When the spacer 30 having such an overlapping region is formed, mixing of air bubbles can be suppressed.

[0117] The fuel cell 100 of the embodiment includes the gasket 30 obtained by the above-mentioned gasket forming method, and the workpiece 10 is a fuel cell component 101. Furthermore, the fuel cell component 101 is selected from the group consisting of a spacer 101a, an electrolyte membrane 101d, a frame 101f, and an electrolyte membrane / electrode assembly 101e. It should be noted that the workpiece 10 including the gasket 30 can also be called a composite.

[0118] The manufacturing method of the fuel cell 100 of the embodiment includes: a coating step S1, which coats the active energy ray-curable liquid 20 in the cavity 41 of the forming mold 40; a bonding step S2, which bonds the forming mold 40 coated with the active energy ray-curable liquid 20 to the fuel cell component 101; a curing step S3, which cures the coated active energy ray-curable liquid 20 by irradiation with active energy rays; and a demolding step S4, which peels the cured active energy ray-curable liquid 20 together with the fuel cell component 101 from the forming mold 40.

[0119] Thus, the gasket forming method can also be applied to the method for manufacturing the fuel cell 100. In addition, the gasket forming method of the present invention can form the gasket 30 under low pressure and can form the gasket 30 by bonding under low load, thereby reducing the load on the fuel cell component 101.

[0120] The sealing method of the embodiment is a sealing method for sealing two workpieces 10 with each other, and includes: a forming step S10 of forming a gasket 30 on one workpiece 10 by the above-mentioned gasket forming method; and a crimping step S20 of arranging another workpiece 10 on the gasket 30 formed on one workpiece 10, and crimping one workpiece 10 to the other workpiece 10. In this way, the gasket forming method can also be applied to the sealing method.

[0121] The gasket forming device of the embodiment includes: a coating device that discharges the active energy ray curing liquid 20 onto the workpiece 10 using a dispenser 50; a bonding device that includes a transparent forming mold 40 and bonds the workpiece 10 to the forming mold 40; a driving device that moves the workpiece 10 and the dispenser 50 relative to each other; and an active energy ray irradiation device 60 that irradiates the active energy ray curing liquid 20. Thus, by discharging the active energy ray curing liquid 20 using the dispenser 50, the gasket 30 can be formed at a low pressure.

[0122] As mentioned above, although the preferred embodiment of the present invention has been described in detail, the present invention is not limited to the above-mentioned embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

[0123] Description of Reference Numerals

[0124] 10 workpiece, 10a opening, 10b recess

[0125] 20Active energy ray curing liquid

[0126] 30 gaskets

[0127] 40 forming die, 41 cavity, 42 platform part

[0128] 50 distributor, 51 nozzle

[0129] 60Active energy ray irradiation device

[0130] 100 fuel cells

[0131] 101 fuel cell component, 101a spacer, 101b fuel electrode, 101c air electrode, 101d electrolyte membrane, 101e electrolyte membrane / electrode assembly, 101f frame, 101g cooling water passage

[0132] St coating start point, En coating end point

Claims

1. A gasket forming method, which is a gasket forming method for forming a gasket on a workpiece, The gasket forming method is as follows include: A coating step of coating an active energy ray-curable liquid having a structural viscosity ratio of 1.5 or more and 4.0 or less into a cavity of a forming mold; a bonding step of bonding the forming mold coated with the active energy ray-curable liquid to the workpiece; a curing step of curing the applied active energy ray-curable liquid by irradiation with active energy rays; as well as a demolding step of peeling the solidified active energy ray-curable liquid together with the workpiece from the molding die, Wherein, the coating process has an overlapping area of ​​the coating track, The structural viscosity ratio is a value obtained by dividing the viscosity at a shear rate of 1.0 by the viscosity at a shear rate of 10.0, wherein the unit of the shear rate is 1 / s and the unit of the viscosity is Pa·s.

2. The gasket forming method according to claim 1, in, The active energy ray-curable liquid has a viscosity of 12 Pa·s or more and 100 Pa·s or less at a shear rate of 1.0 at 25° C., wherein the unit of the shear rate is 1 / s.

3. The gasket forming method according to claim 1 or 2, in, The active energy ray-curable liquid has a viscosity of 5 Pa·s or more and 70 Pa·s or less at a shear rate of 10.0 at 25° C., wherein the unit of the shear rate is 1 / s.

4. The gasket forming method according to claim 1 or 2, in, The active energy ray-curable liquid includes an oligomer having an acryl group, an acryl group-containing monomer, a photoradical initiator, and silicon dioxide.

5. The gasket forming method according to claim 4, in, The average particle size of the silicon dioxide is greater than or equal to 15 nm and less than or equal to 8500 nm.

6. The gasket forming method according to claim 4, in, The content of the silicon dioxide is 0.1 mass % or more and 50 mass % or less.

7. The gasket forming method according to claim 1 or 2, in, The forming die has a cavity in a trapezoidal shape.

8. The gasket forming method according to claim 1 or 2, in, The coating process is performed using a dispenser.

9. The gasket forming method according to claim 8, in, The relative moving speed of the dispenser in the coating step is 1 mm / sec or more and 500 mm / sec or less.

10. The gasket forming method according to claim 1 or 2, in, The overlapping area of ​​the coating track includes a coating start point and a coating end point.

11. The gasket forming method according to claim 1 or 2, in, The overlapping area of ​​the coating tracks includes the intersection of one track with the other tracks.

12. The gasket forming method according to claim 1 or 2, in, The cavity of the forming mold is treated with a waterproof coating.

13. A gasket obtained by the gasket forming method according to claim 1 or 2.

14. A composite body comprising a fuel cell component as a workpiece and a gasket obtained by the gasket forming method according to claim 1 or 2.

15. A fuel cell comprising the composite body according to claim 14.

16. The fuel cell according to claim 15, in, The fuel cell component is selected from a separator, an electrolyte membrane, a frame, and an electrolyte membrane / electrode assembly.

17. A sealing method, which is a sealing method for sealing two workpieces together. include: A forming step, wherein the gasket is formed on a workpiece by the gasket forming method according to claim 1 or 2; as well as The pressure-bonding step includes placing another workpiece on the gasket formed on the one workpiece, and pressure-bonding the one workpiece and the other workpiece.

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