Proprietary curing module and method for impregnating graphite

Abstract

An apparatus and method for curing a solvent impregnated (or impregnated) graphite component includes a curing module in which a graphite component impregnated with a sealant is positioned. The water is then placed in a curing module until the graphite part is immersed in the water. The curing module is then pressurized to between 1 bar and 20 bar or more, and the temperature of the water is maintained at any temperature of 90 DEG C to 225 DEG C or more.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 405,421, filed on September 10, 2022, entitled Proprietary Curing Module and Method for Impregnated Graphite, the contents of which are not inconsistent with this application and are incorporated herein by reference. Background Art

[0003] Impregnated graphite plates are used in fuel cells. In order to obtain graphite plates with the right properties, the graphite plates must be impregnated (or saturated) with a sealant and then cured to produce the final plate (or "finished plate"). Other graphite parts (or "components") are also impregnated and cured. Depending on the thickness, shape, size, and type of graphite, the process currently takes about forty-five minutes to six hours, so production facilities must include a considerable number of machines (or curing stations) to achieve a high output of finished graphite plates.

[0004] "Graphite part" or "graphite component" means any component formed from new graphite, including but not limited to sheets, gears, plates, bushings, circuits, or others. As used herein, cross-linking, cross-polymerization, and curing are used interchangeably to mean curing a liquid sealant into a solid. As used herein, "sealant," "resin," and "polymer" are used interchangeably. Summary of the invention

[0005] An apparatus (or system) and method are disclosed that reduce the curing time to produce a finished graphite part from about forty-five minutes to six hours to less than 45 minutes and as low as about ten minutes or even less. The apparatus and method of the present disclosure utilize a four-module machine to perform graphite impregnation and curing, wherein each module is preferably loaded from the front rather than from the top or side. The apparatus preferably has four modules: (1) a vacuum impregnation module, in which the graphite part is impregnated with a solvent; (2) a rinse module, in which the impregnated graphite part is rinsed with water to remove excess solvent from the outer surface of the part; (3) a wash module, in which the graphite part is washed, such as with water and a surfactant, to further remove excess solvent from the outer surface of the part; and (4) a curing module, in which a sealant on the interior of the graphite part is cured. In the curing module, the uncured impregnated graphite part is placed inside a first chamber, which in the disclosed embodiment is the upper chamber. A heating medium (such as oil), another suitable liquid, or most preferably water, is then moved into the first chamber so that the graphite part is completely immersed. The water is preferably introduced at a temperature of about 85°C-95°C, or 90°C-95°C, or 95°C-100°C, but it may be introduced at any suitable temperature.

[0006] In this embodiment, water is moved out of the second chamber (also referred to as the lower chamber) by pressurizing the second chamber, which causes the water to move from the second chamber through a pipe or other conduit into the first chamber, where the impregnated graphite part is located. The graphite part is then immersed in the water. The first chamber is then pressurized so the water temperature can be raised to or above its boiling temperature of 100°C at atmospheric pressure (1 bar).

[0007] Aspects of the present disclosure include maintaining the pressure in the first chamber at any amount from 1.0 bar to 20 bar or more while increasing / maintaining the temperature of the water to any amount from 90° C. to 225° C. or more in order to cure the sealant in the graphite part. As a non-limiting example, the pressure may be increased by any amount from 1.1 bar to 20 bar or more, and the temperature of the water may be increased by any amount from 100° C. to 225° C. or more.

[0008] The sealant is preferably a methacrylate-based monomer that is thermally cured. Preferably, but not necessarily, the sealant has a viscosity of 12 centipoise and contains no acid. The sealant may include a trifunctional monomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a front view of a device according to the present disclosure.

[0010] Figure 2 is a top view of an apparatus according to the present disclosure.

[0011] Figure 3 is a front perspective view of an apparatus according to the present disclosure.

[0012] Figure 4 is a front view of a curing module according to the present disclosure.

[0013] Figure 5 is a curing module according to the present disclosure Figure 4 A side cross-sectional view taken along line AA. DETAILED DESCRIPTION

[0014] Turning to the drawings, the purpose is to describe preferred embodiments of the present disclosure without limiting the scope of the claims.

[0015] Figure 1-3An apparatus / system 10 according to aspects of the present disclosure is shown. The apparatus shown includes four modules: (1) an impregnation module 20; (2) a rinse module 30; a cleaning module 40; and a curing module 50. Each of the modules 20, 30, 40, and 50 is preferably front loaded using a respective door 20A, 30A, 40A, and 58. A transfer platform 100 is preferably positioned in front of each of the modules 20, 30, 40, and 50 so that containers (also referred to as "baskets" or "racks" herein) of graphite components (also referred to as parts) such as graphite plates for fuel cells are moved into and out of each of the modules 20, 30, 40, 50 through the doors in the front of each module and moved from one module to another along the transfer platform 100.

[0016] The functions and operating conditions of the vacuum impregnation module 20, the rinsing module 30, and the cleaning module 40 are described herein and are generally known in the art. It is not necessary to utilize one of the rinsing module 30 and the cleaning module 40. The original (before being impregnated) graphite component is first loaded into the module 20 through the door 20A, and the door 20A is closed and sealed so that it is waterproof during the process described herein. Then, the graphite component is immersed in the sealant by moving the sealant from a separate vessel of the module 20 (which may be a lower vessel) to the portion of the module 20 in which the graphite component is positioned (which may be an upper vessel). First, a vacuum is drawn on the original graphite component to remove air from its pores. Then, the liquid sealant is moved into the module 20 by vacuum, the vacuum draws the sealant into the portion of the module 20 in which the graphite component is located, and the vacuum draws the sealant into the graphite component. The graphite part is immersed in a liquid sealant, and the chamber containing the graphite part and the sealant is then overpressurized to 1 bar or more to help saturate or impregnate the graphite part with the liquid sealant. The liquid sealant preferably has two components, which are a monomer and an activator that crosslinks (also called cures) the monomer.

[0017] When the graphite parts are sufficiently impregnated with the sealant, the overpressure is removed, the pressure is thus returned to atmospheric pressure, the excess sealant is collected, and the container with the graphite parts is moved out of the vacuum impregnation module 20. The container is then moved along the transfer platform 100 and positioned into the rinsing module 30 through the door 30A at the front of the module 30. The door of the rinsing module 30 is then closed, and water is used to rinse the excess sealant off the surface of the graphite parts.

[0018] After rinsing, the graphite parts are moved along the transfer platform 100 to the cleaning module 40 and loaded into the module 40 through the door 40A in front of the module 40. The cleaning module 40 uses water and surfactants to further remove excess sealant from the outer surface of the graphite parts. The positions of the cleaning module 40 and the rinsing module 30 can be reversed so that the graphite parts are first placed in the cleaning module and then placed in the rinsing module. Moreover, the cleaning and rinsing of the graphite parts can be performed in a single module. Alternatively, one of the rinsing module 30 and the cleaning module 40 can be potentially eliminated.

[0019] After cleaning, the front door of the module 40 is opened, and the container of graphite parts is moved along the transfer platform 100 to the front of the curing module 50 and loaded into the top portion 52 of the module 50 through the front door 58. The front door is then closed and preferably sealed with an inflatable seal. The lower (or bottom) portion 52 of the module 50 contains water that can be preheated to, for example, 90° C. The lower portion 52 has a heating element 60, and the top portion 54 has a heating element 62.

[0020] Pressure is applied to the bottom portion 52, preferably by pumping air into the bottom portion 52. This causes the water in the bottom portion 52 to move upward through the conduit 56 and into the upper chamber 54 and preferably submerge the graphite component in the water. Preferably, no pump is used to move the water from the lower portion 52 to the upper portion 54. Furthermore, water may be added to the upper portion 54 in any suitable manner and from any suitable source, such as from a water tank beside or above the upper portion 54.

[0021] When the graphite component in the upper portion 54 is submerged in the water, the upper portion is pressurized by any amount from 1 bar to 20 bar or more, and preferably by an amount in excess of 1 bar. The temperature of the water in the upper portion 54 is also preferably raised / maintained above its boiling point at 1 bar, such as by any amount from 100° C. to 225° C. or more, but the temperature may also be any amount from 90° C. to 100° C. By raising the temperature of the water, the sealant cures faster. The amount of pressure and temperature of each graphite product that is cured may vary depending on the type of graphite and / or the thickness, shape, and size of the component.

[0022] Examples include changing the overpressure during the curing step or utilizing superheated water instead of the normally used water (90° C.) specified.

[0023] Vacuum Impregnation Module 20 Features :

[0024] Graphite plates (or "plates", "components" or "parts") are placed into a holding bracket (or "basket" or "container"). The bracket is minimized to prevent damage to the plates and to aid uniformity of sealant coverage. The sealant should preferably seal only the pores inside the plates and recyclate. Recyclate is a term used to describe the part that is sealed with a sealant. Too porous graphite castings or graphite plates cannot be used, so the part is "recyclable" for use in manufacturing. The graphite plates are processed through module 20, where the plates are subjected to a vacuum of approximately 6.5 mbar (pure vacuum) to 27 mbar. This is achieved using, for example, a 10-12HP vacuum pump that is evacuated on module 20. Via a ball valve, as an example, the sealant is introduced into the upper chamber of the module 20 where the graphite parts (here, they are plates) are positioned via vacuum transfer. A vacuum is drawn on the upper chamber, and the vacuum siphons the liquid sealant from the lower reservoir to the upper chamber. After siphoning the sealant into the upper chamber, the part is immersed in the liquid sealant and the vacuum is adjusted to approximately 6.5 mbar. NOTE: The siphon effect causes the vacuum to drift up to ~100 mbar, so the vacuum is pulled back to approximately 6.5 mbar. A vacuum of 6.5 mbar or 0-27 mbar is drawn on the graphite plate while it is submerged in the liquid sealant. Prior to siphoning the sealant, a vacuum is first drawn on the dry (or original) part in order to draw the air out of the graphite part, and the plate is then subjected to an overpressure of approximately 5.5 bar. 3.0 bar to 8.5 bar is a typical range. The hydraulic effect of the overpressure helps push the sealant into the pores of the plate.

[0025] Rinse module 30 function :

[0026] The next step is to subject the plates to a rinse module, where the plates are subjected to a flood rinse. Ideally, the rinsing process removes all excess sealant from the surface of the graphite plates. The goal is to use the shearing action of the water to remove excess sealant from the surface of the graphite parts.

[0027] There is a shuttle drain at the bottom of the processing modules 20, 30, 40 and 50. As shown, the rinse (and cure) modules 30 and 50 have a lower water reservoir and an upper processing chamber above the water reservoir. A high capacity water pump is used to move water from the lower water reservoir to the upper processing chamber to a predefined level (usually above the container (or "basket") holding the graphite plates so that the plates are submerged in the water).

[0028] Once this level is achieved, the shuttle opens and drains approximately 60% of the water from the upper chamber of the module 30 to create a shearing / peeling effect of the water on the surface of the graphite plate to strip the sealant from the outer surface. The water fills from the bottom of the module followed by a pre-programmed series of draining sequences to strip the sealant. The number of fills and drains depends on the number of plates processed between the water and the sealant used.

[0029] A surfactant may be used, preferably a non-ionic surfactant mixed with the rinse or wash water at a concentration of 10%-15%. This is introduced into the module 30 or 40 via a dosing unit which involves adjusting the level of the chemical included in the batch or process stream to maintain a set concentration. This is preferably achieved by monitoring the process using an online instrument which automatically controls the chemical dosing to maintain the appropriate level without overdosing or underdosing to aid in rinsing of the board. Rinsing is successful when there is no sealant or surfactant residue visible on the exterior of the component.

[0030] Cleaning module 40 function :

[0031] The graphite plates are then subjected to a cleaning module 40 where a flood cleaning process is utilized where process water is preferably filled from the bottom of the module 40. Uncured graphite plates are fragile and overhead pumping of process water (water coming from the top) may damage the plates, so the module 40 is preferably filled gradually from the bottom. The container holding the plates is also rotated 60 degrees at 4 RPM in either direction (clockwise or counterclockwise) to help move the plates in the carrier to ensure good cleaning, followed by a series of drain sequences. A preferred number of cleaning steps is 5, however, the number of cleaning steps depends on the component. The drain sequence in the module 40 uses a shearing action to strip residual excess sealant and surfactant from the outer surface of the graphite plates. Cleaning is successful when there is no sealant or surfactant residue visible on the exterior of the component.

[0032] Curing module 50 function :

[0033] The curing module in the preferred embodiment comprises a dual chamber unit, wherein the lower chamber 52 module water is heated to an amount from 87°C to 95°C and most preferably about 90°C, and the lower chamber 52 is maintained at a pressure of any amount from 1 bar to 14 bar. Heat is maintained in the lower chamber 52 until the water is transferred from the lower module 52 to the upper module 54. Once the transfer of water from the lower chamber 52 to the upper chamber 54 is completed, the secondary heater 58 maintains the process temperature (e.g., superheated water) in the upper chamber 54. The temperature in the upper chamber 54 may be from 90°C-225°C or higher or from 90°C to 135°C or from 100°C to 225°C or higher. At the same time, the upper chamber 54 is pressurized to any amount from 1 bar to 20 bar or more, or preferably above atmospheric pressure to any amount from 1.1 bar to 20 bar or more. Before the cycle begins, a graphite plate is added to the upper chamber.

[0034] Systematic sequence of operations for preparing finished graphite sheets:

[0035] Vacuum Impregnation Module 20 Process Sequence :

[0036] (1) The operator or robot (if equipped) pushes the carrier into the vessel.

[0037] (2) The operator activates the start switch.

[0038] (3) The vacuum pump is turned on.

[0039] (4) The door closes to seal the module 20 with the panels inside.

[0040] (5) The seal on the module 20 door is inflated to a set point controlled by a programmable logic controller (PLC). The door seal pressure is preferably 10 PSI above the module 20 pressure set point. Example: If the module 20 pressure set point is 5.5 bar, the door seal set point is 6.2 bar.

[0041] (6) The reservoir and module 20 exhaust valves are closed, and the sealant transfer valve is closed.

[0042] (7) Reservoir vacuum valve opens. Pulling a vacuum on the reservoir conditions the sealant and makes the transfer less turbulent. If no vacuum is present, the sealant may bubble as the transfer to the upper chamber occurs due to the pressure differential from atmospheric pressure to the near-pure vacuum pressure in the upper chamber where the plate is positioned. Pulling a vacuum helps remove air that has entered the sealant during transfer from the lower module to the upper module and back again.

[0043] (8) Vessel Vacuum Valve. The vessel vacuum is connected to the reservoir via a 4" butterfly valve. The lower reservoir holds, maintains and cools the sealant to 22°C between cycles. The upper module is an ASME certified process chamber.

[0044] (9) When the vacuum reaches the PLC controlled set point, the reservoir vacuum valve closes. The vacuum set point is variable, but typically it is 6.5 mbar.

[0045] (10) When the vacuum in the upper chamber reaches the set point controlled by the human machine interface (HMI), the vessel vacuum valve closes. The vacuum set point is variable, but typically it is 6.5 mbar.

[0046] (11) The vessel vacuum is maintained in the upper chamber for the dry vacuum set time. This time depends on the part, for example, if the porosity of the part is less than a few microns, the hold time is longer, but typically this is only a hold time of 1 second. A longer hold time gives air more time to escape the pores.

[0047] (12) The transfer valve opens.

[0048] (13) The recovery valve opens for a time controlled by the HMI to recover sealant from the vessel door drip pan. Reservoir vacuum is used to recover sealant from the front drip pan. The set time is 2 seconds.

[0049] (14) The reservoir vent valve opens after a delay controlled by a programmable logic controller (PLC) to allow air to enter the reservoir so the sealant can be properly transferred. This allows the air to occupy the volume space occupied by the sealant to facilitate transfer.

[0050] (15) When the sealant reaches the proper level in the upper chamber, the vessel sealant level sensor turns “ON”.

[0051] (16) The transfer valve and reservoir exhaust valve are closed.

[0052] (17) A wet vacuum of approximately 6.5 mbar is applied to the upper chamber, where the components are preferably covered (submerged) in the sealant. A vacuum is drawn on the plate for a time controlled by the HMI. The vacuum hold time is defined by the operator in the HMI. Typically, the time is 1 second, but can be any suitable time.

[0053] (18)The vacuum valve is closed.

[0054] (19) The pressure valve opens.

[0055] (20) When the pressure reaches a set point (such as 5.5 bar) and is determined via a pressure transducer (sensor), the pressure valve closes.

[0056] (21) Maintaining pressure in the upper chamber for a pressure hold time allows the overpressure to drive the sealant into the pores of the plate for a longer period of time. The hold time is any period of time appropriate for the type, size, shape, and thickness of the component.

[0057] (22) The vessel exhaust valve is open.

[0058] (23) The transfer valve opens at a pressure level controlled by the PLC. This is a safety circuit that requires atmospheric pressure readings from both the pressure transducer and the zero pressure switch.

[0059] (24) The reservoir exhaust valve is opened.

[0060] (25) Once the sealant transfer to the lower reservoir is complete, the carrier (also referred to herein as a "container" or "basket") welded steel construction is rotated for a controlled time set operator set point, which can be any suitable time, but is typically 60CW (clockwise motion) - 60CCW (counterclockwise motion) from the HMI. The centrifuge carrier rotates first clockwise, and then counterclockwise. This is a step to help recover the sealant.

[0061] (26) The carriage stops at the home position. The home position is preferably the top dead center, which is determined by an incremental encoder.

[0062] (27) Deflate the vessel door seal.

[0063] (28) The door is opened manually. The operator grabs the basket via the handle and slides the basket to the rinse module. All subsequent transfers are performed in this way.

[0064] Rinse Module 30 Process Sequence :

[0065] (1) An operator or robot (if equipped) transfers the carrier from the vacuum impregnation module to the rinse module.

[0066] (2) The operator turns on the start switch on the rinse module.

[0067] (3) The rinse module door is closed with the tray inside.

[0068] (4) Start the pump.

[0069] (5) The carriage rotates for a controlled time based on the operator set point from the HMI. For parts with complex geometries, longer centrifugation times are generally required. The carriage rotates first clockwise and then counterclockwise. The number of rotations is tailored to the customer application and part type.

[0070] (6) The upper chamber is filled with water from the lower chamber. The amount of water used for filling is typically between 56-75 gallons, depending on the equipment.

[0071] (7) When the water reaches the upper liquid level sensor, the drain shuttle opens.

[0072] (8) After a PLC controlled delay (which may be 3 seconds), the drain shuttle closes.

[0073] (9) The drain shuttle opens and closes, repeating the sequence until the HMI-controlled rinse time is over. The time is typically 20-500 seconds, and then the drain shuttle remains open. An open drain valve is a safe state.

[0074] (10) The dosing unit provides a mixture of surfactants into the lower chamber to maintain several hundred gallons in the lower chamber to aid in the board rinsing process.

[0075] (11) The bracket stops at the original position.

[0076] (12) The rinse door is open.

[0077] (13) The drain shuttle is closed.

[0078] (14) If the water level drops below the upper level switch, the make-up valve opens between cycles and then closes once the level switch is turned on.

[0079] Cleaning module 40 process sequence :

[0080] (1) The operator or robot (if equipped) transfers the rack from the rinse module to the wash module.

[0081] (2) The operator activates the start switch.

[0082] (3) The cleaning module door is closed.

[0083] (4) The cleaning module pump starts.

[0084] (5) The carriage rotates for a controlled time operator set point; first clockwise, and then counterclockwise. This sequence of steps is tailored to the customer application. The components should be clean of surfactant dosed in the rinse module.

[0085] (6) The upper chamber is filled with water from the lower chamber.

[0086] (7) When the water reaches the upper liquid level sensor in the upper chamber, the drain shuttle opens.

[0087] (8) The drain shuttle closes after a PLC controlled delay, which can be 1-6 seconds and is triggered by the upper process level sensor approximately halfway up the chamber.

[0088] (9) The drain shuttle opens and closes in a repeating sequence until the HMI controlled rinse time, set based on component volume and component cleanliness, is over, and then the drain shuttle remains open.

[0089] (10) The dosing unit provides a mixture of surfactants into the tank to aid the board cleaning process.

[0090] (11) The bracket stops at the original position.

[0091] (12)The door opens.

[0092] (13) The cleaning module drain shuttle is closed.

[0093] (14) If the water level drops below the upper level switch, the make-up valve opens between cycles and then closes once the level switch is turned on.

[0094] Curing Module 50 Process Sequence :

[0095] (1) An operator or a robot (if the system is equipped with a robot) transfers the rack from the rinse module to the curing module.

[0096] (2) The operator activates the start switch.

[0097] (3) The curing module 50 door is closed with the tray inside.

[0098] (4) The lower water tank 52 begins to be pressurized.

[0099] (5) The transfer valve opens and water begins to transfer to the upper chamber 54.

[0100] (6) When the water reaches the upper liquid level sensor in the upper chamber, the transfer valve closes.

[0101] (7) The water reservoir vent valve opens, thereby returning the lower water tank 52 below the upper (processing) chamber 4 to atmospheric pressure.

[0102] (8) Water is retained in the upper chamber 54. Due to the low conductivity of graphite, when pressurization of the upper chamber 54 of 1 bar to 20 bar or more or 1.1 bar to 20 bar or more occurs, it takes time to transfer enough energy to raise the core temperature of the graphite member.

[0103] (9) Upper chamber 54 heating elements are used to maintain the process temperature at a preferred minimum of any amount from below: 90°C to 135°C or 90°C to 100°C or 100°C to 225°C or higher.

[0104] (10) Once the HMI controlled curing time has elapsed (this time can be determined through laboratory testing), the transfer valve is opened to drain the water from the upper chamber so that the parts can be removed.

[0105] (11) Once the water level is confirmed in the lower reservoir 52 via the level sensor, the module 50 door is opened and the bracket with the cured graphite components is removed.

[0106] (12) If the water level drops below the upper level switch, the make-up valve opens between cycles and then closes once the level switch is switched on.

[0107] Existing technology curing module :

[0108] Figures 6 and 7 depict a prior art curing module 1. The curing module 1 is a vessel having an upper chamber 2 and a lower chamber 3. Water is placed in the lower chamber 3 and is heated and maintained at approximately 90°C. The parts that have been impregnated with sealant and then rinsed and cleaned are positioned in the upper chamber 2 through the door 4. The door 4 is closed, and water from the lower chamber 3 is pumped (using a pump) into the upper chamber 2 to immerse the graphite parts in 90°C water. The heat from the water cures the sealant. The water is then drained from the upper chamber 2 and the graphite parts with the cured sealant are removed. The prior art process takes approximately 45 minutes to 6 hours to cure the sealant in the graphite parts.

[0109] Exemplary parameters for the process performed by the apparatus of the present disclosure are as follows:

[0110]

[0111]

[0112] The device features sensors to check temperature and pressure.

[0113] Exemplary Graphite Part Properties

[0114] The preselection stage is the chloroform extraction test. The process (or method or protocol) of the standard mode is described as follows: equilibrate at 35°C, isothermal for 1 minute, ramp to 190°C at 10°C / min.

[0115] Viscosity of liquid sealant

[0116] The Zahn viscosity cup method is used to measure the viscosity of the sealant. The Zahn cup is completely lowered below the surface of the sealant in the beaker. The viscosity cup is removed from the sealant and a timer is started. The timer stops when the sealant is completely discharged from the viscosity cup. Current viscosity specifications are between 20 and 30 seconds. Since viscosity affects sealant absorption and void filling, higher viscosity resins may not work properly. The viscosity of the sealant is important, as dictated by Poiseuille's law or equation.

[0117] Although viscosity can be measured using a Zahn cup, it is not the most accurate. The preferred method is to use a Brookfield viscometer, which will provide a viscosity measurement in centipoise (cps). When measured on a 00 spindle, the sealant is 5cps-15cps@25°C.

[0118] Curing curve, DSC

[0119] The cure profile of the sealant is measured by a Q20 TA Instruments Differential Scanning Calorimetry (DSC) tool or equivalent. This measurement is performed on the sealant sample to determine the exothermic reaction from the cure. The tool measures the heat flow of the sealant sample, producing results including the enthalpy change (ΔH). DSC can quantify the heat released during the reaction, thus providing information about the cure mechanism.

[0120] The sealant sample should be operated under a nitrogen stream of 50 mL / min. The mass of the sealant added to the dish should be between 10 and 15 mg. In order to minimize the sealant on the side of the wicking sample dish, an embossed graphite plate or a flat blank (a sample of a die-punched 4 mm diameter) can be placed at the bottom of the dish to absorb the sealant to allow more contact with the dish and the furnace. The sealant sample should be sealed inside the DSC dish (preferably an airtight cover) and then loaded into the DSC chamber.

[0121] One exothermic peak indicates that only the desired reaction is taking place. This is generally preferred because the cross-linking reaction is completed in one step.

[0122] An exotherm with one or more shoulders or with a small peak results in a Need for Further Investigation (NFI). A small exotherm may indicate residual monomer that has not reacted, which means ineffective initial cure or thermal degradation. Two or more distinguishable exotherms may require further evaluation. It may involve adjusting the cure temperature or activator concentration to help ensure that the sealant is fully cured at the specified temperature.

[0123] Exotherm temperatures that deviate significantly from current production sealant temperatures will cause failure. Higher temperatures (greater than 100°C) will not be achievable in current water cure systems.

[0124] Gel time

[0125] The gel time test is used to estimate whether the liquid sealant is curing within the expected curing curve. If the result exceeds the specification target, the concentration of the activator will be adjusted. A metal wire, a culture test tube, a hot water bath, and a timer are required to perform the gel test. The metal wire is placed in the culture tube so that a portion remains outside the tube and is long enough to hold. The culture tube is then filled with sealant. The hot water bath is preferably about 90°C ± 1°C, and the tube with the sealant is placed in the hot water bath. The water level in the bath should be higher than or equal to the sealant liquid level in the tube so as to thoroughly heat the sealant. After about 90 seconds, lift the wire. If the entire tube is lifted with the wire, the sealant has been cured. If the tube is not lifted, the sealant has not yet been cured, and the wire is placed back in the tube. Then, the operator can check every 3 seconds (by lifting the wire) until the sealant has been cured, and note the time it takes for the sealant to cure. The current specification target for the gel time of the sealant is 1.6 to 2.4 minutes, but it can be any suitable time.

[0126] Bipolar Plate

[0127] (1) Glass transition temperature (Tg), DMA .

[0128] The glass transition temperature (Tg) is the temperature at which the liquid sealant polymer structure changes from a glassy state to a rubbery state. This temperature is evaluated to ensure the mechanical stability of the sealant-impregnated graphite under FC operating conditions. A three-point bending test on a dynamic mechanical analyzer (DMA) is performed to determine the Tg of the impregnated graphite sample. The procedure is based on ASTM D7028 and ISO 6721 guidelines, but any suitable procedure may be utilized.

[0129] A strain controlled block was used with a heating rate of 2°C / min to increase the temperature from 25°C to 210°C. The Tan delta peak is defined as Tg in the presented results according to ASTM D7028. The target to ensure the material is stable under FC operating conditions is Tg>120°C.

[0130] (2) Degree of curing by DSC .

[0131] The degree of liquid sealant of the resin can be measured by a Q20 TA instrument differential scanning calorimetry (DSC) tool or other suitable method. The purpose of this test is to ensure that the sealant inside the graphite plate is fully cured using this procedure. A 4 mm diameter sample of the graphite plate with sealant is die-stamped from the graphite plate and weighed. Typically, the sample mass range for DSC experiments is between 5 and 20 mg, but can be any suitable mass. The sample should be sealed inside the DSC pan and then loaded into the DSC chamber.

[0132] Protocol: equilibrate at 35°C, isothermal for 1 min, ramp to 190°C at 10°C / min.

[0133] Because different sealants exhibit unique cure characteristics, DSC evaluations are usually performed for information only. When testing uncured sealants, one should note the following trends and behaviors:

[0134] One exothermic peak indicates that only the desired reaction is taking place. This is generally preferred because the cross-linking reaction is completed in one step.

[0135] Exotherms with one or more shoulders or with small peaks raise a need for further investigation (NFI). A small exotherm may indicate residual monomer that has not reacted, which means ineffective initial cure or thermal degradation.

[0136] Two or more distinguishable exothermic peaks may warrant further evaluation. This may involve adjusting the cure temperature or activator concentration to help ensure that the sealant is fully cured at the specified temperature.

[0137] Exotherm temperatures that deviate significantly from current production sealant temperatures will cause failure. Higher temperatures (greater than 100°C) may not be achievable in current water cure systems.

[0138] (3) Example Method Pattern: Standard .

[0139] Protocol: equilibrate at 35°C, isothermal for 1 min, ramp to 210°C at 5°C / min.

[0140] The presence of an exothermic peak would indicate that the sealant is not fully cured and that the sealant is undergoing additional curing. A heat flow-temperature plot for a fully cured sealant should be a flat line with no peaks. Avoid temperatures exceeding the sealant degradation temperature.

[0141] (4) Extractables on cured graphite sheets .

[0142] Refer to ISO 1407:2011 for additional guidance. It is recommended to break the graphite sheets into small pieces to increase the surface area for solvent penetration. Chloroform or solvent may be used to determine the integrity of the sealant cure. If uncured monomer is present, it may affect the performance of the fuel cell through permeability, heat transfer or other properties.

[0143] Extractables are measured by mass loss of solvent and GC-MS or GC-FID. First, the sealant is cured into thin sheets by cross-polymerization. Thin sheets of graphite (thickness can vary and can range from 0.2mm-0.8mm or any suitable thickness) are first vacuum impregnated with the sealant. The impregnated sheets are then thermally cured at a specified time and temperature. Once cured, the graphite sheet is allowed to cool to room temperature before being immersed in the solvent. The immersion time can vary and can be any suitable time. At the completion of the immersion, the solvent is analyzed for any uncured monomers. Because, after the sheet is fully cured, thicker samples may be more difficult to extract using solvents. This is customer specific. An appropriate solvent (such as DCM / MeOH (90:10)) should be used to soak the fully cured graphite sheet impregnated with the resin. The graphite sealant sheet soaks for approximately 2 hours at room temperature. After soaking, the graphite sealant sheet is dried and the final mass of each sheet is measured. The percentage of extractables can be calculated from the mass difference. Subsequently, GC-MS or GC-FID can be performed on the remaining solvent to determine the leachable monomers and contaminants. – The goal is to detect any uncured monomers in the graphite sheet as these will be extracted in the solvent.

[0144] (5) Void filling rate calculation .

[0145] The void fill percentage of the impregnated graphite plate should be calculated using the following formula: % void fill = (post weight - pre weight) / resin density + plate volume - (pre weight / graphite density).

[0146] Pre-weight = weight of plate before impregnation. Post-weight = weight of graphite plate after impregnation. Plate volume is measured by water displacement method. The impregnated plate is submerged in a deionized water tank and the volume of water displaced is measured using a graduated cylinder. However, any suitable method may be used.

[0147] Example properties, test methods and target values ​​of finished (cured) graphite sheets and test methods used to determine the same Down :

[0148]

[0149] Typical material targets for finished graphite sheets made according to the methods of the present disclosure :

[0150]

[0151]

[0152] Some non-limiting examples of the present disclosure are as follows:

[0153] Example 1: A sealant configured to penetrate and seal for use in hydrogen (H 2) A graphite plate for use in a fuel cell wherein the seal is a mixture of ethoxylated monomers.

[0154] Example 2: The sealant of Example 1, which is configured to cure in 10 minutes or less or less than 45 minutes after being impregnated in a graphite sheet and the graphite sheet is pressurized and heated.

[0155] Example 3: The sealant of any of Examples 1-2, wherein the cure time is determined by a chloroform extraction test.

[0156] Example 4: The sealant of any of Examples 1-3, wherein the extractables in the cured graphite plate impregnated with the sealant are <10% by weight.

[0157] Example 5: The sealant of any of Examples 1-3, wherein the viscosity at 25°C is 2-30 centipoise (cP).

[0158] Example 6: The sealant of any of Examples 1-4, having a cure profile of <100 minutes at a temperature <100°C.

[0159] Example 7: The sealant of Example 6, wherein the cure curve is calculated at atmospheric pressure.

[0160] Example 8: The sealant of any of Examples 1-7, having a gel time in a 90° C. water bath of from 1.5 minutes to 3 minutes.

[0161] Example 9: The sealant of any of Examples 1-8 having a reactive resin stability without curling at 40°C for up to 1 week.

[0162] Example 10: The sealant of any of Examples 1-9, providing a flexural strength of the impregnated graphite plate at 95°C that is <30% reduced from the RT strength.

[0163] Example 11: The sealant of any of Examples 1-10, providing a through-plane voltage of <20 millivolts (mV) to a cured graphite plate impregnated with the sealant.

[0164] Example 12: The sealant of any one of Examples 1-11, wherein the sealant is a methacrylate-based monomer.

[0165] Example 13: The sealant of any of Examples 1-12, having a viscosity of 12 centipoise.

[0166] Example 14: The sealant of any of Examples 1-13, which does not contain an acid.

[0167] Example 15: The sealant of any of Examples 1-14, comprising a trifunctional monomer.

[0168] Some further non-limiting examples of the present disclosure are as follows:

[0169] Example 1: A method of making a graphite plate impregnated with a sealant, comprising the steps of increasing the curing temperature and increasing the curing pressure.

[0170] Example 2: The method of Example 1, further comprising the step of measuring extractables by mass loss of solvent.

[0171] Example 3: The method of Example 2, wherein the extractables are further measured by one or both of GC-MS and GC-FID of the solvent.

[0172] Example 4: The method of any of Examples 1-3, further comprising the step of curing the graphite sheet after impregnation with the sealant.

[0173] Example 5: The method of any one of Examples 1-4, wherein a solvent is used, and the solvent is DCM / MeOH.

[0174] Example 6: The method of Example 5, wherein the solvent is 90% DCM and 10% MeOH.

[0175] Example 7: The method of any of Examples 1-6, further comprising the step of soaking the graphite sheet in a sealant.

[0176] Example 8: The method of Example 7, wherein the graphite sheet is completely immersed in the sealant during the soaking step.

[0177] Example 9: The method of any of Examples 7-8, wherein the soaking step lasts for about 2 hours.

[0178] Example 10: The method of any of Examples 7-9, wherein the soaking step is performed at room temperature of 65°F-80°F.

[0179] Example 11: The method of any of Examples 9-10, further comprising the step of rinsing the graphite sheet.

[0180] Example 12: The method of Example 11, further comprising the step of drying the graphite sheet after it has been removed from the sealant bath.

[0181] Example 13: The method of any of Examples 7-12, further comprising the step of cleaning the graphite sheet.

[0182] Example 14: The method of any of Examples 7-16, further comprising the step of measuring the mass of each graphite sheet.

[0183] Example 15: The method of any one of Examples 7 - 14, further comprising the step of calculating the mass percentage of the extractable matter of each graphite sheet.

[0184] Example 16: The method of Example 15, wherein the mass percentage of the extractable matter is calculated by subtracting the weight of the graphite sheet after drying from the weight of the graphite sheet before drying.

[0185] Example 17: The method of any one of Examples 7 - 16, wherein the step of performing GC - MS or GC - FID on the remaining solvent is carried out to determine the leachable monomers and / or contaminants in the remaining solvent.

[0186] Example 18: The method of any one of Examples 1 - 17, wherein the viscosity of the sealant is measured using a Zahn viscosity cup.

[0187] Example 19: The method of Example 18, wherein the viscosity is measured at atmospheric pressure and a temperature of 65°F - 80°F.

[0188] Example 20: The method of any one of Examples 1 - 22, further comprising the step of mixing a monomer with an activator to obtain a liquid sealant.

[0189] Example 21: The method of Example 20, wherein the mixing step comprises mixing 80% - 92% monomer by weight with 8% - 20% activator.

[0190] Example 22: The method of any one of Examples 20 - 21, wherein the sealant cures in the graphite sheet at a pressure greater than atmospheric pressure.

[0191] Example 23: The method of any one of Examples 20 - 22, wherein the sealant cures in the graphite sheet at a temperature of 100°C - 225°C or higher.

[0192] Example 24: The method of Example 23, wherein the sealant cures at 90°C - 100°C.

[0193] Some further non - limiting examples of the present disclosure are as follows:

[0194] Example 1: A method for forming an impregnated graphite sheet configured for use in a hydrogen (H 2 ) fuel cell, the method comprising the following steps:

[0195] (a) impregnating a graphite sheet with a sealant;

[0196] (b) heating the graphite sheet to cure the sealant;

[0197] (c) adding a solvent to the added thin graphite sheet; and

[0198] (d) Determine the final mass in the solvent sheet.

[0199] Example 2: The method of Example 1, wherein the solvent is DCM / MeOH.

[0200] Example 3: The method of Example 2, wherein the solvent is DCM / MeOH in a weight percentage of 90:10.

[0201] Example 4: The method of any of Examples 1-3, wherein the graphite sheet is immersed in the sealant during the dipping.

[0202] Example 5: The method of Example 4, wherein the graphite sheet is immersed in the sealant for 1.5-2.5 hours.

[0203] Example 6: The method of Example 4, wherein the graphite sheet is immersed in the solvent for 2 hours.

[0204] Example 7: The method of any of Examples 1-6, further comprising the step of measuring the percentage of solvent extractables in the graphite sheet.

[0205] Example 8: The method of Example 7, wherein the step of measuring the percentage of extractables includes the step of measuring a mass difference between a mass of the graphite flakes after removal of the graphite flakes from the solvent and a mass of the graphite flakes after drying.

[0206] Example 9: The method of any of Examples 1-8, wherein the amount of extractables is determined by GC-MS or GC-FID of the remaining solvent.

[0207] Example 10: The method of any of Examples 1-9, further comprising measuring a viscosity of the sealant.

[0208] Example 11: The method of Example 10, wherein the viscosity is measured using a Zahn viscosity cup.

[0209] Example 12: The method of Example 11, further comprising the step of placing the sealant in a beaker, wherein the sealant in the beaker has a top surface.

[0210] Example 13: The method of Example 12, wherein the Zahn viscosity cup is positioned below the top surface in the beaker.

[0211] Example 14: The method of any of Examples 12-13, further comprising removing the Zahn viscosity cup from the beaker and draining the sealant from the Zahn viscosity cup.

[0212] Example 15: The method of any of Examples 13-14, wherein the resin is discharged within 20-30 seconds.

[0213] Example 16: The method of any of Examples 1-15, wherein the sealant comprises a cure profile.

[0214] Example 17: The method of Example 16, wherein the cure profile of the sealant is measured by a differential scanning calorimetry (DSC) tool.

[0215] Example 18: The method of any of Examples 15-17, wherein a cure curve is used to determine an exothermic reaction from the cure.

[0216] Example 19: The method of Example 17, wherein the DSC tool measures the heat released during the curing reaction.

[0217] Example 20: The method of any of Examples 1-19, wherein the sealant sample is run under a nitrogen flow of 50 mL / min.

[0218] Example 21: The method of any of Examples 1-20, further comprising the step of adding a sealant to the pan.

[0219] Example 22: The method of Example 21, wherein 1-15 mg of sealant is added to the disc.

[0220] Example 23: The method of any of Examples 21-22, further comprising the step of placing a graphite plate in the bottom of the tray.

[0221] Example 24: The method of Example 23, wherein the graphite sheet is embossed or is a flat blank.

[0222] Example 25: The method of Example 24, wherein the graphite plate comprises openings.

[0223] Example 26: The method of any of Examples 21-26, further comprising the step of curing the sealant on the interior of the tray.

[0224] Example 27: The method of Example 26, further comprising the step of loading the disc into the DSC chamber.

[0225] Example 28: The method of Example 27, wherein the temperature of the interior of the DSC chamber is maintained at 35°C.

[0226] Example 29: The method of Example 28, wherein the temperature of the interior of the DSC chamber is maintained at 35°C for 1 minute.

[0227] Example 30: The method of Example 29, wherein after 1 minute, the temperature of the interior of the DSC chamber is increased to 190°C.

[0228] Example 31: The method of Example 30, wherein the temperature is increased at a rate of 10°C / min.

[0229] Example 32: The method of any of Examples 1-31, further comprising the step of performing a gel time test configured to determine whether the resin cures within the proper time.

[0230] Example 33: The method of Example 32, wherein if the gel time is too long, the method is adjusted to add more activator to the resin.

[0231] Example 34: The method of Example 33, wherein the step of conducting a gel time test comprises the steps of: (a) placing a metal wire inside a culture tube, (b) placing a resin inside a culture tube; and (c) placing the culture tube in a water bath, wherein the water bath is maintained at 90°C + / - 1°C and wherein the resin liquid level in the tube is below the surface of the water bath.

[0232] Example 35: The method of Example 34, further comprising the step of maintaining the culture tube in a water bath for 90 seconds.

[0233] Example 36: The method of Example 36, further comprising the step of an operator grasping and lifting the metal wire.

[0234] Example 37: The method of Example 36, wherein if lifting the wire lifts the culture tube, the resin is cured, and if lifting the wire does not lift the culture tube, the resin is uncured.

[0235] Example 38: The method of Example 37, wherein if the resin is not cured, the wire is placed back into the resin in the culture tube.

[0236] Example 39: The method of any of Examples 37-38, further comprising the step of lifting the wire until the culture tube is lifted when the wire is lifted.

[0237] Example 40: The method of any of Examples 34-39, further comprising the step of measuring the time it takes for the resin to cure.

[0238] Example 41: The method of any of Examples 34-40, wherein the target cure time is from 1.6 to 2.4 minutes.

[0239] Some further non-limiting examples of the present disclosure are as follows:

[0240] Example 1: A method for producing a 2 ) An impregnated graphite plate for use in a fuel cell, wherein the impregnated graphite plate comprises graphite impregnated with a cured sealant, and the impregnated graphite plate has a glass transition temperature (Tg) greater than 120°C.

[0241] Example 2: The impregnated graphite plate of Example 1, wherein the glass transition temperature is determined by using a three-point bending test according to ASTM D7028 and ISO6721.

[0242] Example 3: The impregnated graphite plate of Example 2, with the temperature increased from 25°C to 210°C using a strain controlled module with a heating rate of 2°C / min.

[0243] Example 4: The impregnated graphite plate of any of Examples 1-3, wherein the degree of cure of the sealant inside the plate is determined.

[0244] Example 5: The impregnated graphite plate of Example 4, wherein the curing was determined by removing a 4 mm diameter sample from the graphite plate and weighing it.

[0245] Example 6: The impregnated graphite plate of Example 5, wherein the sample mass is from 5 to 20 milligrams (mg).

[0246] Example 7: The impregnated graphite plate of any of Examples 1-6, further comprising the step of calculating a void filling fraction.

[0247] Example 8: The impregnated graphite plate of Example 7, wherein the void filling fraction is calculated by: (a) obtaining the weight of the graphite plate before impregnation with the polymer; (b) obtaining the weight of the graphite plate after impregnation; (c) obtaining the volume of the plate.

[0248] Example 9: The impregnated graphite plate of any of Examples 1-8, wherein the void filling ratio is ≥ 95%.

[0249] Example 10: The impregnated graphite plate of any of Examples 1-9, wherein the flexural strength is >20 mPa.

[0250] Example 11: The impregnated graphite plate of any of Examples 1-9, wherein the flexural strength is >20-30 mPa.

[0251] Example 12: The impregnated graphite plate of any of Examples 1-11, wherein the conductivity is <20 mV.

[0252] Example 13: The impregnated graphite plate of any of Examples 1-12, wherein the hydrophilicity is <105°C.

[0253] Example 14: The impregnated graphite plate of any of Examples 1-13, wherein the impregnated graphite plate has extractables < 3% by weight.

[0254] Example 15: The impregnated graphite plate of any of Examples 1-14, wherein the degree of cure of the resin on the impregnated graphite plate is such that there is no exotherm below 200°C.

[0255] Example 16: The impregnated graphite plate of any of Examples 1-15, wherein the impregnated graphite plate has leak-free air tightness.

[0256] Some further non-limiting examples of the present disclosure are as follows:

[0257] Example 1: A curing module for curing a graphite sheet impregnated with a sealant, wherein the curing module includes: a first chamber and a second chamber, wherein the first chamber includes heated water, and the second module includes a graphite plate impregnated with the sealant, a transfer valve is positioned between the first chamber and the second chamber, wherein the transfer valve is configured to allow water to pass between the first chamber and the second chamber when the valve is open; a pressure source, which is in communication with the first chamber and is configured to pressurize the first chamber; and a heating source, which is in communication with the second chamber and is configured to heat the second chamber.

[0258] Example 2: The curing module of Example 1, wherein the first chamber is below the second chamber.

[0259] Example 3: The curing module of any of Examples 1-2, further comprising a second heater in communication with the first chamber and configured to heat water.

[0260] Example 4: The curing module of any of Examples 1-3, wherein the pressure source is configured to pressurize the water in the first chamber sufficiently to move at least some of the water into the second chamber when the transfer valve is opened.

[0261] Example 5: The curing module of any of Examples 1-4, wherein the second chamber is maintained at atmospheric pressure.

[0262] Example 6: The curing module of any of Examples 1-5, wherein the first heater is configured to maintain the water at a temperature of 90°C + / - 1°C.

[0263] Example 7: The curing module of any of Examples 1-6, wherein the second heater is configured to maintain the water at a temperature of 90°C + / - 1°C.

[0264] Example 8: The curing module of any of Examples 1-7, wherein the second chamber is configured to retain water for 10 minutes or less after the water is transferred from the first module.

[0265] Example 9: The curing module of any of Examples 1-8, wherein the valve is moved to its closed position after water has been transferred from the first module to the second module.

[0266] Example 10: The curing module of any of Examples 1-9, wherein the valve moves to its open position to allow water to move from the second chamber to the first chamber.

[0267] Example 11: An apparatus for impregnating a graphite sheet with a sealant, wherein the apparatus comprises:

[0268] (a) Vacuum impregnation module;

[0269] (b) rinsing module;

[0270] (c) a cleaning module; and

[0271] (d) Curing module of Example 1.

[0272] Example 12: The curing module of any of Examples 1-10, wherein the first chamber has a volume of 600 liters.

[0273] Example 13: The curing module of any of Examples 1-10 or 12, wherein the second chamber has a volume of 600 liters.

[0274] Some further non-limiting examples of the present disclosure are as follows:

[0275] Example 1: A method for impregnating a graphite sheet with a sealant, wherein a curing module having a first chamber and a second chamber is used, the method comprising the following steps:

[0276] (a) adding one or more graphite sheets to a first chamber of a curing module;

[0277] (b) adding heated water to the first chamber;

[0278] (c) maintaining the heated water in the first chamber for 10 minutes or less;

[0279] (d) removing water from the first chamber; and

[0280] (e) removing the one or more impregnated graphite plates from the first chamber.

[0281] Example 2: The method of Example 1, wherein an operator activates a start switch.

[0282] Example 3: The method of any of Examples 1-2, further comprising the step of closing the curing module door after the one or more impregnated graphite sheets are positioned in the first chamber.

[0283] Example 4: The method of any of Examples 1-3, wherein the heated water is in the second chamber before being added to the first chamber.

[0284] Example 5: The method of any of Examples 1-4, wherein the second chamber is below the first chamber.

[0285] Example 6: The method of any of Examples 1-5, further comprising the step of pressurizing the water in the second chamber to move it into the first chamber.

[0286] Example 7: The method of Example 6, wherein a transfer valve is present between the first chamber and the second chamber, and the transfer valve is opened and the heated water is transferred to the first chamber.

[0287] (a) When water reaches the upper level sensor, the transfer valve closes.

[0288] (b) The water reservoir vent valve opens, thereby returning the reservoir in the lower chamber to atmospheric pressure.

[0289] (c) When pressurization of the upper chamber occurs (1 bar to 20 bar), water is retained in the upper chamber.

[0290] (d) Upper chamber heating element is used to maintain process temperature.

[0291] (e) Once the HMI controlled cure time set by the operator (determined by when the sealant cures) has elapsed, the transfer valve opens.

[0292] (f) Once the water level is confirmed in the lower reservoir via the liquid level sensor, the module door opens.

[0293] (g) If the water level drops below the upper level switch, the make-up valve opens between cycles and then closes once the level switch is switched on.

[0294] Example 8: The process of any of Examples 1-7, wherein a vacuum impregnation module is utilized, the process further comprising the step of impregnating the graphite sheet with a sealant.

[0295] Example 9: The process of any of Examples 1-8, wherein, using a rinse module, the process further comprises the step of rinsing the graphite sheet.

[0296] Example 10: The process of any of Examples 1-9, wherein, using a cleaning module, the process further comprises the step of cleaning the graphite sheet.

[0297] Some further non-limiting examples of the present disclosure are as follows:

[0298] Example 1: A method for curing a sealant in a graphite component, wherein the method includes: (a) placing the graphite component impregnated with the sealant into a curing module, (b) closing the curing module with the impregnated graphite component inside, (c) adding a heating medium to the curing module to at least partially immerse the graphite component in the heating medium, (d) increasing the pressure in the curing module to above 1 bar; and (e) maintaining the temperature of the curing module at any temperature of 90°C-225°C or higher.

[0299] Example 2: The method of Example 1, wherein the graphite component is a plate.

[0300] Example 3: The method of Example 1 or Example 2, wherein the sealant is a mixture of ethoxylated monomers.

[0301] Example 4: The method of any of Examples 1-2, wherein the sealant is a methacrylate-based monomer.

[0302] Example 5: The method of any of Examples 1-4, wherein the sealant has a viscosity of 12 centipoise.

[0303] Example 6: The method of any of Examples 1-5, wherein the sealant does not contain an acid.

[0304] Example 7: The method of any of Examples 1-6, wherein the sealant includes a trifunctional monomer.

[0305] Example 8: The method of any of Examples 1-7, wherein the pressure is increased to any amount from 1.1 bar to 20 bar or more.

[0306] Example 9: The method of any of Examples 1-8, wherein the heating medium is water.

[0307] Example 10: The method of any of Examples 1-9, wherein the graphite component is completely immersed in the heating medium.

[0308] Example 11: The method of any of Examples 1-10, configured to cure the sealant in less than 45 minutes.

[0309] Example 12: The method of any of Examples 1-11, configured to cure the sealant in 10 minutes or less.

[0310] Example 13: The method of any of Examples 1-11, configured to cure the sealant in any time from 10 minutes to 40 minutes.

[0311] Example 14: The method of any of Examples 1-13, wherein the curing module comprises an upper chamber and a lower chamber.

[0312] Example 15: The method of Example 14, wherein the graphite component is positioned in the upper chamber.

[0313] Example 16: The method of Example 14 or Example 15, further comprising the step of pressurizing the lower chamber to move at least some of the heating medium from the lower chamber into the upper chamber.

[0314] Example 17: The method of any of Examples 1-16, wherein after the sealant is cured, the graphite component has a void filling fraction of 95% or greater.

[0315] Example 18: The method of any of Examples 1-17, wherein after the sealant is cured, the graphite component has a gas porosity of zero.

[0316] Example 19: The method of Example 16, wherein the lower chamber is not pressurized after at least some of the heating medium moves to the upper chamber.

[0317] Example 20: The method of Example 16 or Example 19, further comprising the step of moving at least some of the heating medium back to the lower chamber after the sealant cures.

[0318] Example 21: The method of any of Examples 1-20, further comprising the step of saturating the graphite component with a liquid sealant prior to curing the sealant.

[0319] Example 22: The method of Example 21, further comprising the step of rinsing excess liquid sealant from the graphite component after saturating the graphite component.

[0320] Example 23: The method of Example 21 or Example 22, further comprising the step of washing excess liquid sealant from the graphite component after saturating the graphite component.

[0321] Thus having described some embodiments of the invention, other variations and embodiments will become apparent to those skilled in the art without departing from the spirit of the invention. Unless explicitly stated in the written description or claims, the steps of any method recited in the claims may be performed in any order that produces the desired results.

Claims

1. A method for curing one or more graphite sheets impregnated with a sealant using a curing module having a first chamber and a second chamber, the method The following steps are involved: (a) adding one or more graphite sheets to the first chamber of the curing module; (b) adding heated water from the second chamber to the first chamber; (c) maintaining the heated water at a temperature of 90° C. to 225° C. in the first chamber for 10 to 45 minutes; (d) removing the heated water from the first chamber; and (e) removing one or more impregnated graphite plates from the first chamber.

2. The method according to claim 1, further comprising the step of pressurizing the water in the first chamber from 1.1 to 20 bar.

3. The method of claim 1 or claim 2, further comprising the step of closing a curing module door after the one or more impregnated graphite sheets are positioned in the first chamber.

4. The method according to any one of claims 1 to 3, in, The heated water in the second chamber is at atmospheric pressure prior to being added to the first chamber.

5. The method according to any one of claims 1 to 4, in, The second chamber is below the first chamber.

6. The method of any one of claims 1-5, further comprising the step of pressurizing the water in the second chamber to move it into the first chamber.

7. The process according to any one of claims 1 to 6, in, Using a vacuum impregnation module, the process further includes the step of impregnating the one or more graphite sheets with a liquid sealant prior to curing the graphite sheets.

8. The process according to any one of claims 1 to 7, in, Using the rinsing module, the process further includes the step of rinsing the one or more graphite sheets after the one or more graphite sheets have been impregnated with the liquid sealant and before curing the one or more graphite sheets.

9. The process according to any one of claims 1 to 8, in, Using the cleaning module, the process further includes the step of cleaning the one or more graphite sheets after the one or more graphite sheets have been impregnated with the liquid sealant and before curing the one or more graphite sheets.

10. A method of curing a liquid sealant in one or more graphite parts, in, The method comprises: (a) placing the one or more graphite parts impregnated with the liquid sealant into a curing module; (b) closing the curing module with the impregnated graphite parts inside; (c) adding a heating medium into the curing module to immerse the impregnated graphite parts in the heating medium; (d) increasing the pressure in the curing module to above 1 bar; and (e) increasing the temperature of the heating medium in the curing module to any temperature from 90°C to 225°C or higher.

11. The method according to claim 10, in, The one or more graphite components are one or more graphite plates for a hydrogen fuel cell.

12. The method according to claim 10 or claim 11, in, The liquid sealant includes a mixture of ethoxylated monomers.

13. The method according to any one of claims 10 to 12, in, The liquid sealant includes a methacrylate-based monomer.

14. The method according to any one of claims 10 to 13, in, The liquid sealant had a viscosity of 12 centipoise at 25°C.

15. The method according to any one of claims 10 to 14, in, The liquid sealant does not contain an acid.

16. The method according to any one of claims 10 to 15, in, The liquid sealant includes a trifunctional monomer.

17. The method according to any one of claims 10 to 16, in, The pressure in the curing module is raised to anywhere from 1.1 bar to 20 bar or more.

18. The method according to any one of claims 10 to 17, in, The heating medium is water.

19. The method of any one of claims 10-18, configured to cure the liquid sealant in the impregnated graphite component in less than 45 minutes.

20. The method of any one of claims 10-19, configured to cure the liquid sealant in the impregnated graphite component in 10 minutes or less.

21. The method of any one of claims 10-20, configured to cure the liquid sealant in the impregnated graphite component in any time from 10 minutes to 45 minutes.

22. The method according to any one of claims 10 to 21, in, After the liquid sealant is cured, the one or more graphite components have a void filling rate of 95% or greater.

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