Gasket molding method, gasket, member for fuel cell, fuel cell, method for manufacturing fuel cell, sealing method, and gasket molding device

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: a coating step (S1) of coating an active energy ray-curable liquid inside a cavity of a molding die; a bonding step (S2) in which the molding die coated with the active energy ray-curable liquid is bonded to a workpiece; a temporary curing step (S3) in which active energy rays having a cumulative light amount with a reaction rate of 20-85% are irradiated; a release step (S4) in which the temporarily cured active energy ray-curable liquid is released from the molding mold together with the workpiece; and a main curing step (S5) in which active energy rays having a reaction rate of more than 85% but 100% or less of an accumulated light amount are irradiated. As a result, provided is a gasket molding method capable of improving productivity even when a molding die is used.

Description

Technical Field

[0001] The invention relates to a sealing gasket forming method, a sealing gasket, a fuel cell component, a fuel cell, a fuel cell manufacturing method, a sealing method and a sealing gasket forming device. Background Art

[0002] As a member for sealing between two members, a gasket is known. Such a gasket is generally molded by injection molding in which a mold having a cavity having a desired shape is filled with a molding resin such as a thermoplastic resin.

[0003] On the other hand, as another gasket molding method, for example, Patent Document 1 describes directly applying an ultraviolet curing resin on a workpiece and curing it by irradiating it with ultraviolet rays, thereby molding the gasket on the workpiece.

[0004] The above-mentioned Patent Document 1 describes that the connection between the coating starting point and the coating end point is pressed with a light-transmitting member while being cured. However, since the coating is directly applied to the workpiece, the viscosity and quality of the ultraviolet curing resin will cause sagging before curing, and the shape stability (especially the height dimension) is poor.

[0005] Therefore, a molding method has been studied in which an ultraviolet curable resin is applied to a molding die having a cavity and then cured while the molding die and the workpiece are bonded together.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-159287 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, in the case of this molding method, as shown in FIG8 , it is confirmed that exhaust 21' (left figure of FIG8 ) such as volatile components contained in the ultraviolet curing resin 20' is generated along with curing, which adheres to the cavity 41' of the molding mold 40' and accumulates (accumulates) as the number of times the molding mold is used increases (right figure of FIG8 ). In addition, if the accumulation 22' accumulates in the cavity 41' of the molding mold 40', the dimensional accuracy of the gasket after molding deteriorates. In addition, sometimes damage occurs due to the transfer marks of the accumulation, which reduces the sealing performance. Therefore, it is necessary to perform cleaning operations such as cleaning, sweeping, and wiping of the molding mold every certain number of uses, resulting in a deterioration in productivity.

[0011] Therefore, the present invention is completed in view of the above problems, and its purpose is to provide a gasket molding method, a gasket, a fuel cell component, a fuel cell, a fuel cell manufacturing method, a sealing method and a gasket molding device that can improve productivity even when a molding mold is used.

[0012] Methods for solving problems

[0013] (1) One embodiment of the present invention is a gasket molding method for molding a gasket on a workpiece, comprising: a coating step of coating an active energy ray-curable liquid in a mold cavity of a transparent molding mold; a bonding step of bonding the molding mold coated with the active energy ray-curable liquid to the workpiece; a temporary curing step of irradiating the coated active energy ray-curable liquid with active energy rays having a reaction rate calculated from an IR spectrum of not less than 20% and not more than 85% of the accumulated light amount; a demolding step of peeling the temporarily cured active energy ray-curable liquid from the molding mold together with the workpiece; and a full curing step of irradiating the temporarily cured active energy ray-curable liquid with active energy rays having a reaction rate calculated from an IR spectrum of not less than 85% and not more than 100%.

[0014] (2) In the above-mentioned aspect (1), the temporary curing step may be performed by irradiating with a wavelength of 320 nm to 450 nm and a power of 500 mW / cm 2 Above and 5000mW / cm 2 Active energy rays with peak illuminance below.

[0015] (3) In the above-mentioned method (1) or (2), the temporary curing step may be performed by irradiating 100 mJ / cm 2 Above and 500mJ / cm 2 The applied active energy ray curable liquid is temporarily cured by irradiating the active energy ray with a low accumulated light amount of 1000 mJ / cm 2 Above and 10000mJ / cm 2 The active energy ray having a high cumulative light amount is then used to fully cure the temporarily cured active energy ray-curable liquid.

[0016] (4) In any one of the aspects (1) to (3) above, the coating step may be performed using a dispenser.

[0017] (5) In any one of the aspects (1) to (4) above, the molding die may be formed of one or more materials selected from the group consisting of polymethyl methacrylate, cycloolefin polymer, polycarbonate, and glass.

[0018] (6) In any one of the aspects (1) to (5) above, the workpiece may be a fuel cell component.

[0019] (7) Another aspect of the present invention is a gasket obtained by the gasket molding method according to any one of (1) to (5) above.

[0020] (8) Another aspect of the present invention is a fuel cell component comprising a gasket obtained by the gasket molding method according to any one of (1) to (6) above.

[0021] (9) Another aspect of the present invention is a fuel cell comprising a gasket obtained by the gasket molding method according to any one of (1) to (6) above.

[0022] (10) The method for manufacturing a fuel cell using the above-mentioned aspect (6), wherein the fuel cell component is selected from the group consisting of a separator, an electrolyte membrane, a frame, and an electrolyte membrane / electrode assembly.

[0023] (11) Another embodiment of the present invention is a sealing method for sealing two components together, comprising: a molding step of molding a sealing gasket on one component by a sealing gasket molding method according to any one of the above-mentioned methods (1) to (6); and a crimping step of arranging another component on the sealing gasket molded on the one component and crimping the one component to the other component.

[0024] (12) Another embodiment of the present invention comprises: a coating device for discharging an active energy ray-curable liquid onto a molding die by means of a dispenser; a driving device for moving the molding die and the dispenser relative to each other; a bonding device comprising the molding die having transparency and bonding the workpiece to the molding die; and an active energy ray irradiation device for irradiating the active energy ray-curable liquid with active energy rays, wherein the active energy ray irradiation device irradiates the applied active energy ray-curable liquid with active energy rays having a reaction rate calculated from an IR spectrum of not less than 20% and not more than 85% through the molding die, and irradiates the temporarily cured active energy ray-curable liquid peeled off from the molding die together with the workpiece with active energy rays having a reaction rate calculated from an IR spectrum of not less than 85% and not more than 100%.

[0025] Effects of the Invention

[0026] According to the present invention, a gasket molding method, a gasket, a fuel cell component, a fuel cell, a method for manufacturing a fuel cell, a sealing method, and a gasket molding device that can improve productivity even when a molding die is used can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic plan view showing a workpiece on which a gasket is molded.

[0028] FIG. 2A is a flowchart showing a gasket molding method according to an embodiment of the present invention.

[0029] FIG. 2B is an operation diagram showing the gasket molding method according to the embodiment of the present invention.

[0030] FIG. 3 is a schematic perspective view showing a molding die.

[0031] FIG. 4 is a schematic cross-sectional view showing a fuel cell.

[0032] FIG. 5 is a flow chart showing a sealing method for sealing two components together.

[0033] FIG. 6 is a graph showing the durability performance of a molding die in the gasket molding method according to the embodiment.

[0034] FIG. 7 is a graph showing the durability performance of a molding die according to a conventional gasket molding method.

[0035] FIG. 8 is a schematic diagram showing a state in which exhaust gas components are deposited in a molding die in a conventional gasket molding method. DETAILED DESCRIPTION

[0036] Hereinafter, 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 reference numerals are used throughout to denote the same components.

[0037] First, before describing the gasket molding method according to the embodiment of the present invention, a workpiece 10 on which a gasket 30 is molded will be briefly described. Fig. 1 is a schematic plan view showing the workpiece 10 on which a gasket 30 is molded.

[0038] 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, polyvinyl chloride, polyethylene naphthalate, polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, and the like. It should be noted that the workpiece 10 of the present embodiment is a rectangular plate.

[0039] The workpiece 10 is formed with one or more openings 10a or one or more recesses 10b. A sealing gasket 30 is formed around the openings 10a and recesses 10b. The workpiece 10 preferably has a flat surface on which the sealing gasket 30 is formed, but may also have a gently inclined surface.

[0040] 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 .

[0041] Next, a gasket molding apparatus used in the gasket molding method according to the embodiment of the present invention will be briefly described.

[0042] The gasket molding device mainly includes a coating device, a laminating device, an XYZ axis driving device, a first active energy ray irradiation device 60, a demolding device, a second active energy ray irradiation device 70, and a control device.

[0043] The coating device can apply the liquid to the coating object, and it can be a coating device used in a coating method such as a dispenser, a sprayer, an inkjet, screen printing, gravure printing, etc., wherein a dispenser is preferred. The coating device of this embodiment is composed of a dispenser 50 that discharges the liquid from the nozzle toward the coating object, a tank or a barrel that stores the liquid, and a pump that supplies the liquid. It should be noted that a rotating mechanism that rotates the nozzle around the Z axis can also be provided.

[0044] The laminating device may be a clamshell type laminating device, which includes a fixed table holding one laminating object (molding 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.

[0045] In addition, the laminating device also includes a CCD camera or other photographing device for photographing the laminating object, which can be used to confirm the position and inclination of the laminating object 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.

[0046] 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 can 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 can also be composed of an XY table that holds the dispenser 50 and a Z table that holds the coating object.

[0047] The first active energy ray irradiation device 60 irradiates ultraviolet rays, electron beams, etc. having a wavelength of about 320nm to 450nm, and is configured as a linear light source or a planar light source by a UV lamp or UV-LED. The active energy ray irradiation device 60 is movably or fixedly arranged relative to the coating object.

[0048] In addition, if the first active energy ray irradiation device 60 can irradiate with 500 mW / cm 2 Above and 5000mW / cm 2 Below, preferably 1500mW / cm 2 Above and 5000mW / cm 2 Active energy rays with a peak illuminance of 0.5 or less are preferred because they can suppress the curing shrinkage of the active energy ray-curable liquid 20 and improve the dimensional stability. Furthermore, the accumulated light amount can be adjusted by setting the irradiation time.

[0049] On the other hand, the second active energy ray irradiation device 70 also irradiates ultraviolet rays, electron beams, and other light with a wavelength of more than 320nm and less than 450nm, and is formed into a linear light source or a planar light source by a UV lamp or UV-LED. The active energy ray irradiation device 70 is movable or fixed relative to the irradiation object. It should be noted that the active energy ray irradiation device 70 is preferably capable of irradiating a 500mW / cm 2 Above and 5000mW / cm 2 It is preferable that the irradiation time of the active energy ray with the following peak illuminance be adjustable.

[0050] The control device comprehensively controls the coating device, the laminating device (demolding device), the XYZ-axis driving device, the first and second active energy ray irradiation devices 60 and 70, for example, by controlling the rotation speed (rotation speed, rotation angle) of the pump to adjust the discharge volume of the dispenser 50, or by controlling the rotation speed (rotation angle) of the flip driving unit to adjust the laminating load and the pressing amount, and perform load control or position control based on the movable table, or by driving each driving unit of the XYZ-axis driving device to perform position control and speed control of the dispenser 50, or control the supply power of the first and second active energy ray irradiation devices 60 and 70 to adjust the irradiation output of the light source.

[0051] Next, a gasket molding method for molding the gasket 30 on the workpiece 10 using the active energy ray-curable liquid 20 will be described.

[0052] FIG. 2 shows a gasket molding method according to an embodiment of the present invention, FIG. 2A is a flow chart, and FIG. 2B is an operation diagram.

[0053] The active energy ray-curable liquid 20 is an ultraviolet-curable resin that reacts and cures by irradiating active energy rays (e.g., ultraviolet rays), and may be, for example, a (meth)acrylate composition that undergoes free radical polymerization or an epoxy composition that undergoes cation polymerization. For example, ThreeBond 3178 (manufactured by ThreeBond Co., Ltd.) may be cited.

[0054] 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 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 1 Pa·s or more and 300 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 2.0 or more and 6 or less. By making these viscosities or structural viscosity ratios within the above range, it is more suitable for the sealing gasket molding method of the embodiment of the present invention. It should be noted that the viscosity and structural viscosity ratio can be obtained using a rheometer.

[0055] Examples of the (meth)acrylate composition for free radical polymerization include compositions containing (meth)acryloyl-containing oligomers, (meth)acryloyl-containing reactive diluents, and photoradical initiators. The (meth)acryloyl-containing oligomers are not particularly limited, and examples thereof include polycarbonate-based urethane (meth)acrylates, polyether-based urethane (meth)acrylates, polyester-based urethane (meth)acrylates, castor oil-based urethane (meth)acrylates, polybutadiene-based urethane (meth)acrylates, hydrogenated polybutadiene-based urethane (meth)acrylates, polyisobutylene-based (meth)acrylates, silicone-based (meth)acrylates, isoprene-based (meth)acrylates, hydrogenated isoprene-based (meth)acrylates, (meth)acryloyl-containing acrylic polymers, and the like. Among these, polyisobutylene-based (meth)acrylates are preferred. The reactive diluent containing a (meth)acryloyl group 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, 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, and dimethoxybenzene (meth)acrylate. Cyclopentenyloxyester, isobornyl (meth)acrylate, adamantyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, acryloylmorpholine, morpholinylethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, and the like. 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.

[0056] As the epoxy composition for the above-mentioned cationic polymerization, for example, a composition containing a cationic polymerizable compound and a photocationic initiator can be cited. In addition, as the above-mentioned cationic polymerizable compound, there is no particular limitation, and for example, epoxy resins, alicyclic epoxy resins, oxetane compounds, vinyl ether compounds, etc. can be cited. In addition, as the above-mentioned photocationic initiator, there is no particular limitation, and for example, onium salts such as aromatic iodonium salts and aromatic sulfonium salts can be cited.

[0057] 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.

[0058] Examples of the silica include hydrophilic silica, hydrophobic silica, etc. As the hydrophobic silica, silica treated with hydrophobicity using organochlorosilanes, polyorganosiloxane, hexamethyldisilazane, etc. can be used.

[0059] The gasket molding method according to the embodiment of the present invention includes a coating step S1 , a laminating step S2 , a temporary curing step S3 , a mold releasing step S4 , and a main curing step S5 in this order.

[0060] In the coating step S1 , first, the active energy ray-curable liquid 20 is applied into a desired gasket shape while being moved in a cavity 41 of a molding die 40 described later, for example, in a stroke trajectory, by a dispenser 50 .

[0061] Here, the molding die 40 will be described. FIG. 3 is a schematic perspective view showing the molding die 40. As shown in FIG.

[0062] The molding die 40 is held on a fixed table of the laminating device and has a cavity 41 having a shape corresponding to the gasket 30 to be molded. The cavity 41 is, for example, circular, elliptical, or rectangular, and the inner side thereof is formed as a land portion 42. However, the cavity 41 may be in any shape, such as 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.

[0063] In addition, the cavity 41 is formed so that its cross section is substantially rectangular, substantially trapezoidal, substantially triangular (mountain-shaped), substantially semicircular, or the like, which is the same as the desired cross-sectional shape of the gasket 30. 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.

[0064] The molding die 40 is formed of a transparent material through which light can pass, for example, one or more materials selected from the group consisting of polymethyl methacrylate, cycloolefin polymer, polycarbonate and glass. The surface of the cavity 41 may be subjected to a surface treatment to improve mold release properties.

[0065] Returning to FIG. 2A , the description of the coating step S1 will be continued.

[0066] In the coating step S1, the dispenser 50 preferably discharges an amount of at least 100% of the volume per unit length of the cavity 41, i.e., a discharge amount per unit length, in such a manner 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%.

[0067] Next, in the bonding process S2, the fixed table of the bonding device holding the molding mold 40 coated with the active energy ray-curing liquid 20 and the movable table holding the workpiece 10 are flipped toward each other to bond the molding mold 40 and the workpiece 10 via the uncured active energy ray-curing liquid 20.

[0068] At this time, the lamination is performed with a lamination load of low pressure (e.g., less than 1 MPa). It should be noted that the lamination load can be performed while measuring the lamination pressure and controlling the pressure, or while measuring the lamination amount (pressing amount) and controlling the position. In this way, the sealing gasket 30 can be formed by lamination with a low load, thereby reducing the load on the workpiece 10.

[0069] Next, in the temporary curing step S3 , the active energy ray curing liquid 20 interposed between the molding die 40 and the workpiece 10 is temporarily cured by irradiating the active energy ray with the active energy ray irradiation device 60 .

[0070] At this time, the active energy ray irradiation device 60 is disposed on the side opposite to 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 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.

[0071] Here, when the active energy ray-curable liquid 20 is irradiated with active energy rays and cured, the acryloyl group (CH2=CH-C-) or methacryloyl group (CH2=C(CH3)-) contained in the active energy ray-curable liquid 20 is reduced. Therefore, the reaction rate of the active energy ray-curable liquid 20, that is, the degree of curing, can be calculated based on the reduction rate of the acryloyl group or methacryloyl group before and after the irradiation.

[0072] The reduction rate of the acryloyl group or methacryloyl group was determined by measuring the IR spectrum using FT-IR (Perkin Elmer, Spectrum 100). Specifically, the FT-IR spectrum of the active energy ray-curable liquid 20 before irradiation was measured at 1635 cm from the base line. -1 The absorption peak height P1 of the active energy ray-curable liquid 20 after irradiation (absorption peak of CH2=CH2- group) and the 1635 cm from the baseline in the FT-IR measurement chart are -1 The absorption peak height P2 is substituted into the following mathematical formula (1) and calculated.

[0073] Reduction rate (reaction rate, curing degree) (%) = ((P1-P2) / P1) × 100···(1)

[0074] Therefore, the relationship between the reaction rate and the irradiation amount (accumulated light amount) of the active energy ray can be determined in advance by experiments. In the temporary curing step S3, the accumulated light amount of the active energy ray is preferably adjusted and irradiated so that the reaction rate of the active energy ray curable liquid 20 is 20% or more and 85% or less. By making the accumulated light amount within the above range, the generation of exhaust gas accompanying curing can be suppressed. Therefore, even if the molding die 40 is repeatedly used, no accumulation will be accumulated in the molding die 40, and the sealing performance of the gasket 30 after molding can be maintained.

[0075] For example, when an active energy ray-curable liquid containing polyisobutylene (meth)acrylate having a viscosity of 45 Pa·s at 25° C. and a structural viscosity ratio of 1.9 (manufactured by ThreeBond Co., Ltd.) is used as the active energy ray-curable liquid 20 to mold the gasket 30, the active energy ray-curable liquid 20 applied to a thickness of 1000 μm is subjected to four types of cumulative light intensity of 20 mJ / cm 2 、300mJ / cm 2 、500mJ / cm 2 、4000mJ / cm 2 Irradiation wavelength 405nm, illumination 1500mw / cm 2 When exposed to active energy rays, the reaction rates were 68%, 77%, 85% and 91% respectively.

[0076] Therefore, the cumulative light intensity in the temporary curing step S3 can be 100 mJ / cm 2 Above and 500mJ / cm 2 Below, preferably 100 mJ / cm 2 Above and 400mJ / cm 2The peak illuminance of the active energy ray is 500mW / cm 2 Above and 5000mW / cm 2 By irradiating the active energy ray having such a high peak illuminance to the active energy ray curable liquid 20, curing starts instantly from the outer layer side, thereby reducing the curing shrinkage rate of the active energy ray curable liquid 20 relative to the cavity 41 of the molding die 40. In addition, the generation of exhaust gas accompanying curing can also be suppressed, so even if the molding die 40 is repeatedly used, no accumulation will be accumulated in the molding die 40, and the sealing performance of the gasket 30 after molding can be maintained.

[0077] Next, in the demolding step S4 , the movable table is turned over so as to be away from the fixed table in the bonding device as a demolding device, and the temporarily cured active energy ray-curable liquid 20 (as the gasket 30 ) is peeled off from (the cavity 41 of) the molding die 40 together with the workpiece 10 .

[0078] Then, in the final main curing step S5 , the temporarily cured active energy ray-curable liquid 20 transferred to the workpiece 10 is irradiated with active energy rays by the second active energy ray irradiation device 70 , thereby mainly curing the temporarily cured active energy ray-curable liquid 20 .

[0079] In the main curing step S5 , the active energy ray-curable liquid 20 that has been temporarily cured at a reaction rate of 20% to 85% is irradiated with an accumulated amount of active energy rays adjusted so that the reaction rate is greater than 85% and less than 100%.

[0080] For example, the accumulated light intensity in the main curing step S5 is preferably 1000 mJ / cm 2 Above and 10000mJ / cm 2 The following high cumulative light quantity. It should be noted that the active energy ray irradiation device 70 is provided on the molding surface side of the gasket 30 of the workpiece 10 .

[0081] After that, the workpiece 10 is removed from the movable table to complete the molding step S10, and the workpiece 10 having the sealing gasket 30 directly provided on the surface can be obtained. It should be noted that the removal of the workpiece 10 from the movable table may be performed before the main curing step S5.

[0082] Next, a case where the gasket molding method of this embodiment is applied to a method for manufacturing a fuel cell 100 using a fuel cell component 101 as a workpiece 10 for molding a gasket 30 will be described. FIG4 is a schematic cross-sectional view showing a fuel cell 100.

[0083] Examples of the fuel cell component 101 include a separator 101 a , an electrolyte membrane 101 d , a frame 101 f , and an electrolyte membrane / electrode assembly 101 e (see FIG. 4 ) constituting the fuel cell 100 (single cell), and the gasket 30 is molded thereon.

[0084] Among them, it is preferable to mold the gasket 30 on the separator 101a made of aluminum, stainless steel, titanium, graphite, carbon, etc. In Fig. 4, 101b is a fuel electrode, 101c is an air electrode, and 101g is a cooling water passage.

[0085] Moreover, the manufacturing method of the fuel cell 100 includes, in sequence: a coating step S1, coating the active energy ray-curable liquid 20 in the cavity 41 of the molding mold 40; a bonding step S2, bonding the molding mold 40 coated with the active energy ray-curable liquid 20 to the fuel cell component 101; a temporary curing step S3, temporarily curing the coated active energy ray-curable liquid 20 by irradiating active energy rays; a demolding step S4, peeling the cured active energy ray-curable liquid 20 together with the fuel cell component 101 from the molding mold 40; and a formal curing step S5, formally curing the temporarily cured active energy ray-curable liquid 20.

[0086] Furthermore, a case where the gasket molding method of the present embodiment is applied to a sealing method for sealing between two members will be described. Fig. 5 is a flow chart showing the sealing method for sealing between two members.

[0087] The sealing method for sealing two components includes: a molding step S10 of molding a sealing gasket 30 on one component (for example, the workpiece 10 described above); and a crimping step S20 of crimping one component to another component.

[0088] The molding step S10 is the same as the above-mentioned gasket molding method, and therefore the description thereof is omitted.

[0089] The crimping step S20 is a step of placing another component on the gasket 30 formed on one component to crimp one component 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, if the two components are fastened to each other by screws (bolts), they can also be fastened by screws, or the two components can be crimped to each other by caulking.

[0090] 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.

[0091] Finally, an experiment was conducted on the leakage performance of the gasket 30 formed by the gasket forming method of the present embodiment.

[0092] (Molding conditions)

[0093] An active energy ray-curable liquid (manufactured by ThreeBond Co., Ltd.) containing polyisobutylene (meth)acrylate having a viscosity of 45 Pa·s at 25° C. and a structural viscosity ratio of 1.9 was used as the active energy ray-curable liquid 20, and a molding die having a transparent polymethyl methacrylate and a cavity 41 for the sealing gasket 30 having a width of 1.2 mm and a height of 1.0 mm was used as the molding die 40.

[0094] In addition, a flange plate of 90 mm×90 mm made of aluminum was used as the workpiece 10 .

[0095] The curing conditions were the temporary curing step S3 and the main curing step S5 of Example 1 described below. In addition, for comparison, a member cured by a single curing step was used as Comparative Example 1.

[0096] Then, a total of 3000 gaskets 30 were molded using the same molding die 40 , and the 3000th gasket 30 was molded onto the workpiece 10 , and the following leakage test was performed.

[0097] (Leakage test)

[0098] A flange plate having a gasket 30 formed thereon was fastened to a pressure vessel having a quadrilateral pressure-resistant flange with a flange opening of 80 mm×80 mm and a flange width of 10 mm, and the flange was immersed in water.

[0099] The flange plate was tightened with such a force that the compression rate (collapse amount) of the gasket 30 became 15%.

[0100] Dry air at 25° C. was injected into the pressure vessel immersed in water under the condition of increasing pressure at 50 kPa / 30 seconds until the pressure reached 800 kPa.

[0101] (Leakage determination)

[0102] If there is an air leak of 15 ml (15 cc) or more within 1 second, it is determined to be a leak, and the pressure immediately before the leak is taken as the leak resistance pressure.

[0103] (Example 1)

[0104] In the temporary curing step S3, the first active energy ray irradiation device 60 is used to irradiate the surface of the substrate with a cumulative light intensity of 77% (specifically, 300 mJ / cm 2 )Irradiation wavelength 405nm, illumination 1500mw / cm2 of active energy rays.

[0105] In the main curing step S5, the second active energy ray irradiation device 70 is used to irradiate the solidified ... 2 )Irradiation wavelength 405nm, illumination 1500mw / cm 2 of active energy rays.

[0106] (Comparative Example 1)

[0107] In the single curing step, the active energy ray irradiation device was used with a cumulative light dose (specifically, 4000 mJ / cm 2 )Continuous irradiation wavelength 405nm, illumination 1500mw / cm 2 of active energy rays.

[0108] As a result of the leakage test, the leakage resistance pressure of Comparative Example 1 was 700 kPa. On the other hand, the leakage resistance pressure of Example 1 was 800 kPa, and it was found that the gasket 30 molded by the gasket molding method of the present embodiment was excellent in performance.

[0109] Furthermore, an experiment was conducted to examine the durability of the molding die 40 when the gasket molding method of the present embodiment was used.

[0110] Fig. 6 is a graph showing the durability of the molding die 40 according to the gasket molding method of the embodiment. Fig. 7 is a graph showing the durability of the molding die 40 according to the conventional gasket molding method. It should be noted that in Figs. 6 and 7, the dotted line indicates the target value (550 kPa) of the leakage performance.

[0111] (Durability test)

[0112] The gasket 30 was continuously molded using the same molding die 40, and the above leakage test was performed every predetermined number of times (number of pieces). It should be noted that the leakage test was performed three times for each of the three crushing amounts (10%, 15%, and 20%).

[0113] When the conventional gasket molding method is used, as shown in Fig. 7, the leakage performance of the molded gasket 30 begins to deteriorate when the molding die 40 is used more than 2,600 times, and the sealing pressure resistance reaches about 70% of the target value, i.e., 550 kPa, at 3,700 times. Therefore, the molding die 40 needs to be cleaned, swept, wiped, etc. every time the molding die 40 is used more than 2,000 times, and the productivity (yield) cannot be said to be good.

[0114] On the other hand, when the gasket molding method of the present embodiment is used, as shown in FIG. 6 (the points of each crushing amount are substantially all overlapped), even if the molding die 40 is used more than 10,000 times, the leakage performance of the molded gasket 30 does not change, and a gasket 30 showing a stable sealing pressure resistance can be molded under any fastening conditions. Therefore, the molding die 40 only needs to be cleaned, swept, or wiped every time the molding die 40 is used more than 10,000 times, which can greatly improve productivity.

[0115] As described above, the sealing gasket molding method of the embodiment of the present invention is a sealing gasket molding method for molding a sealing gasket 30 on a workpiece 10, which sequentially includes a coating step S1, a bonding step S2, a temporary curing step S3, a demolding step S4 and a formal curing step S5. In the coating step S1, an active energy ray-curable liquid 20 is coated in a mold cavity 41 of a transparent molding mold 40; in the bonding step S2, the molding mold 40 coated with the active energy ray-curable liquid 20 is bonded to the workpiece 10; and in the temporary curing step S3, a demolding step S4 and a formal curing step S5 are performed. In step S3, the applied active energy ray curable liquid 20 is irradiated with active energy rays with a cumulative light amount of more than 20% and less than 85% of the reaction rate calculated by IR spectrum; in the demolding step S4, the temporarily cured active energy ray curable liquid 20 is peeled off from the molding die 40 together with the workpiece 10; in the formal curing step S5, the temporarily cured active energy ray curable liquid 20 is irradiated with active energy rays with a cumulative light amount of more than 85% and less than 100% of the reaction rate calculated by IR spectrum. Thus, even if the molding die 40 is used more times, accumulation will not accumulate in the molding die 40, and cleaning work can be reduced. In addition, the active energy ray curable liquid 20 can be used to mold the sealing gasket 30 at low pressure.

[0116] In the temporary curing step S3 of the embodiment, the irradiation is performed at a wavelength of 320 nm to 450 nm and 500 mW / cm 2 Above and 5000mW / cm 2 Active energy rays with a peak illuminance of 0.17° or less are used. This can suppress the curing shrinkage of the active energy ray-curable liquid 20, thereby improving the dimensional stability and providing excellent sealing properties for the gasket 30 after molding.

[0117] In the temporary curing step S3 of the embodiment, 100 mJ / cm 2 Above 500mJ / cm 2 The applied active energy ray-curable liquid 20 is temporarily cured by irradiating with active energy rays of a low cumulative light amount of 1000 mJ / cm 2 Above 10000mJ / cm2 The active energy rays with a high accumulated light amount below fully cure the temporarily cured active energy ray-curable liquid 20. Thus, the temporarily cured and fully cured states of the active energy ray-curable liquid 20 can be estimated based on the intensity and time of the active energy rays.

[0118] The coating step S1 of the embodiment is performed using the dispenser 50. Thus, in the coating step S1, it is possible to easily control the discharge amount of the liquid. In this case, for example, when the dispenser 50 is operated in a trajectory of a single stroke, no overlapping portion of the coating trajectory is generated, so the position and speed control of the dispenser 50 can be simplified.

[0119] The molding die 40 of the embodiment is formed of one or more materials selected from the group consisting of polymethyl methacrylate, cycloolefin polymer, polycarbonate and glass. Thus, a transparent molding die 40 can be obtained. In addition, in the temporary curing step S3, active energy rays can be irradiated from the side opposite to the molding surface of the cavity 41.

[0120] The fuel cell 100 of the embodiment includes the gasket 30 obtained by the above-mentioned gasket molding method, and the workpiece 10 is a fuel cell component 101. The fuel cell component 101 is selected from the group consisting of a separator 101a, an electrolyte membrane 101d, a frame 101f, and an electrolyte membrane / electrode assembly 101e.

[0121] The manufacturing method of the fuel cell 100 of the embodiment includes a coating step S1, a bonding step S2, a curing step S3 and a demolding step S4. In the coating step S1, an active energy ray-curable liquid 20 is coated on the cavity 41 of the molding mold 40; in the bonding step S2, the molding mold 40 coated with the active energy ray-curable liquid 20 is bonded to the fuel cell component 101; in the curing step S3, the coated active energy ray-curable liquid 20 is cured by irradiating active energy rays; in the demolding step S4, the cured active energy ray-curable liquid 20 and the fuel cell component 101 are peeled off from the molding mold 40 together.

[0122] Thus, the gasket molding method can also be applied to the method for manufacturing the fuel cell 100. In addition, the gasket molding method of the present invention can be molded at low pressure and can form the gasket 30 by laminating at low load, thereby reducing the load on the fuel cell component 101.

[0123] The sealing method of the embodiment is a sealing method for sealing two components, and includes a molding step S10, in which a sealing gasket 30 is molded on one component by the above-mentioned sealing gasket molding method; and a crimping step S20, in which another component is arranged on the sealing gasket 30 molded on one component, and one component is crimped to the other component. In this way, the sealing gasket molding method can also be applied to the sealing method.

[0124] The gasket forming device of the embodiment includes a coating device, a driving device, a laminating device, and first and second active energy ray irradiation devices 60 and 70. The coating device uses a dispenser 50 to discharge an active energy ray curable liquid 20 onto a molding die 40. The driving device relatively moves the molding die 40 and the dispenser 50. The laminating device includes a transparent molding die 40 and laminates a workpiece 10 to the molding die 40. The first and second active energy ray irradiation devices 60 and 70 irradiate active energy rays to the active energy ray curable liquid 20. Thus, by using the dispenser 50 to discharge the active energy ray curable liquid 20, the gasket 30 can be formed at a low pressure.

[0125] 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.

[0126] (Variation)

[0127] In the above embodiment, the first active energy ray irradiation device 60 used in the temporary curing step S3 is different from the second active energy ray irradiation device 70 used in the formal curing step S5, but for example, they can also be used by one irradiation device. In this case, it is preferable to be able to change the irradiation energy (peak illuminance).

[0128] Description of Reference Numerals

[0129] 10: workpiece, 10a: opening, 10b: recess, 20: active energy ray-curable liquid, 30: sealing gasket, 40: molding die, 41: cavity, 42: land portion, 50: distributor, 60: first active energy ray irradiation device, 70: second active energy ray irradiation device, 100: fuel cell, 101: component for fuel cell, 101a: separator, 101b: fuel electrode, 101c: air electrode, 101d: electrolyte membrane, 101e: electrolyte membrane / electrode assembly, 101f: frame, 101g: cooling water passage.

Claims

1. A sealing gasket forming method, which is a sealing gasket forming method for forming a sealing gasket on a workpiece, comprising: In the coating step, the active energy ray curable liquid is coated in the cavity of the transparent molding die. a laminating step of laminating the molding die coated with the active energy ray-curable liquid to the workpiece, a temporary curing step of irradiating the applied active energy ray-curable liquid with active energy rays having a cumulative light amount of 20% or more and 85% or less of a reaction rate calculated from an IR spectrum; a demolding step of peeling the temporarily cured active energy ray-curable liquid together with the workpiece from the molding die; and In the main curing step, the temporarily cured active energy ray-curable liquid is irradiated with active energy rays having a cumulative light amount that allows a reaction rate calculated from an IR spectrum to be greater than 85% and less than 100%.

2. The sealing gasket forming method according to claim 1, wherein: The temporary curing step irradiates with a wavelength of 320 nm to 450 nm and 500 mW / cm 2 Above and 5000mW / cm 2 Active energy rays with peak illuminance below.

3. The sealing gasket forming method according to claim 1 or 2, wherein: The temporary curing process is performed by irradiating 100mJ / cm 2 Above and 500mJ / cm 2 The applied active energy ray-curable liquid is temporarily cured by active energy rays having a low cumulative light amount as follows, The main curing process is irradiated with 1000mJ / cm 2 Above and 10000mJ / cm 2 The active energy ray having a high cumulative light amount is then used to fully cure the temporarily cured active energy ray-curable liquid.

4. The sealing gasket forming method according to claim 1 or 2, wherein: The coating process is performed using a dispenser.

5. The sealing gasket forming method according to claim 1 or 2, wherein: The molding die is formed of one or more materials selected from the group consisting of polymethyl methacrylate, cycloolefin polymer, polycarbonate, and glass.

6. The sealing gasket forming method according to claim 1 or 2, wherein: The workpiece is a component for a fuel cell.

7. A sealing gasket obtained by the sealing gasket forming method according to claim 1 or 2. 8 . A fuel cell component comprising a gasket obtained by the gasket molding method according to claim 1 or 2 . 9 . A fuel cell comprising a gasket obtained by the gasket molding method according to claim 1 or 2 .

10. A method for manufacturing a fuel cell, which is a method for manufacturing a fuel cell using the gasket molding method according to claim 6, wherein the fuel cell component is selected from the group consisting of a separator, an electrolyte membrane, a frame, and an electrolyte membrane / electrode assembly.

11. A sealing method for sealing two components together, comprising: a molding step, forming the sealing gasket on a component by the sealing gasket molding method according to claim 1 or 2, and The pressure-bonding step includes placing another component on the gasket formed on the one component, and pressure-bonding the one component and the other component.

12. A sealing gasket forming device, comprising: A coating device that discharges an active energy ray-curable liquid onto a molding die using a dispenser, a driving device for moving the molding die and the dispenser relative to each other, A laminating device comprising the transparent molding die and laminating the workpiece to the molding die, and an active energy ray irradiation device for irradiating the active energy ray to the active energy ray-curable liquid; The active energy ray irradiation device irradiates the applied active energy ray-curable liquid through the molding die with active energy rays having a cumulative light amount of more than 20% and less than 85% as calculated by an IR spectrum, and irradiates the temporarily cured active energy ray-curable liquid peeled off from the molding die together with the workpiece with active energy rays having a cumulative light amount of more than 85% and less than 100% as calculated by an IR spectrum.

Images