JP2020051605A - Manufacturing method of high-pressure tank - Google Patents

Abstract

To provide a manufacturing method of a high-pressure tank which is suppressed in variation of Vf and the lowering of tank rigidity.SOLUTION: This invention relates to a manufacturing method of a high-pressure tank which includes: a first process for adjusting a primary intermediate product tank by winding a resin-impregnated fiber around an external periphery of a hollow liner being a tank vessel; and a second process for adjusting the high-pressure tank by hardening the resin-impregnated fiber in the primary intermediate product tank which is adjusted in the first process, by applying heat treatment by electromagnetic induction heating. The second process has: a step for adjusting a secondary intermediate product tank by applying a resin hardener to an external periphery of the primary intermediate product tank when the heat treatment is in a low-viscosity state at a temperature lower than a temperature at which the resin-impregnated fiber starts to be hardened; and a step for adjusting the high-pressure tank by hardening the resin-impregnated fiber by applying a hardening reaction accelerator to an external periphery of the secondary intermediate product tank after the temperature of the heat treatment is raised to the temperature or higher at which the resin-impregnated fiber starts to be hardened.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a high-pressure tank, and particularly to a method for manufacturing a high-pressure tank used for a fuel cell vehicle.

  A high-pressure tank for storing hydrogen gas, natural gas, or the like as a fuel gas is mounted on a fuel cell vehicle, a natural gas vehicle, and the like. As a high-pressure tank, a fiber-reinforced plastic material (FRP material) having a very high strength per unit density, such as a carbon fiber-reinforced plastic material (CFRP material), is provided around the outer periphery of a resin or metal tank (liner: inner container). BACKGROUND ART A high-pressure tank reinforced by winding is known. When manufacturing such a high-pressure tank, for example, a filament winding method is used. In the filament winding method, a carbon fiber or the like is wound around a resin tank in a state where the fiber bundle is impregnated with a matrix resin such as an uncured epoxy resin to form a fiber layer, and then the matrix resin is cured. A reinforcing layer is formed.

  For example, Patent Literature 1 is an apparatus for manufacturing a high-pressure tank for manufacturing a high-pressure tank having a liner and a reinforcing layer configured to include a fiber layer in which fibers are wound around the outer surface of the liner. A device for manufacturing a high-pressure tank, characterized by having a resin applying means for applying a resin to the fiber bundle when the impregnated fiber bundle is wound around the outer surface of the liner, and means for heating the resin As IH heating (electromagnetic induction heating).

  Patent Document 2 discloses a process of winding an uncured state of a first thermosetting resin-impregnated fiber around a hollow liner to form an inner layer, and impregnating an uncured state of a second thermosetting resin. Forming the outer layer by winding the formed fiber around the inner layer; and heating and curing the outer layer from the outer layer side. A method for molding a high-pressure tank, characterized in that the resin has a curing property of being cured before the viscosity of the resin decreases, is disclosed.

  Patent Document 3 discloses a method for manufacturing a high-pressure gas tank, which is a tank intermediate product having a fiber-reinforced resin layer formed by winding fibers impregnated with a thermosetting resin around the outer periphery of a hollow liner serving as a tank container. (A) preparing the tank intermediate product using an induction heating coil that induces high-frequency induction heating while rotating the tank intermediate product around a tank axis while placing the intermediate product in a pressurized environment; And (b) thermally curing the fiber-reinforced resin layer by induction heating.

JP 2011-245740 A JP 2011-230321 A JP 2013-103395 A

  In a high-pressure tank used in a fuel cell vehicle, a fiber layer is formed by winding fibers (also referred to as “resin-impregnated fibers”) such as carbon fibers impregnated with a resin such as an epoxy resin using a device used in a filament winding method. When forming and then curing the fiber layer in a curing furnace, when a thick product such as a tank is heated by indirect heating, the side facing the outside air in the thickness direction of the fiber layer (also referred to as the “outer layer side”) It takes a very long time for only the surface layer of (1) to rise in temperature and to transfer heat to the liner side (also referred to as “inner layer side”) in the thickness direction of the fiber layer.

  On the other hand, IH heating (electromagnetic induction heating) of the direct heating method is useful because a rapid temperature rise can be expected even for a thick product such as a tank. However, in the IH heating, the temperature on the inner layer side becomes too high, the viscosity of the resin on the inner layer decreases, and the resin on the inner layer seeps out to the outside such as the outer layer side. The ratio of fiber to resin per unit volume (Vf: fiber volume content, fiber volume content (fiber / CFRP)) increases, causing variations in Vf and reduction in tank strength.

  Furthermore, when the temperature on the inner layer side is increased, air is easily generated inside the fiber layer, and if air is hardly removed during curing, voids and the like are generated, resulting in poor appearance and reduced performance.

  Therefore, an object of the present invention is to provide a method for manufacturing a high-pressure tank in which variation in Vf and reduction in tank strength are prevented.

  The present inventor has set a resin curing agent (also simply referred to as a “curing agent”) for increasing the resin density and the crosslinking density on the outer layer side during resin curing to prevent the resin from seeping out from the outermost layer. By applying a curing reaction accelerator (also simply referred to as “accelerator”) to the outer periphery of the tank in a curing furnace according to the curing reaction state of the resin, to prevent variations in Vf and a reduction in tank strength. The present invention was completed.

That is, the gist of the present invention is as follows.
(1) a first step of winding a resin impregnated fiber around the outer periphery of a hollow liner serving as a tank container to prepare a primary intermediate production tank;
The second step of preparing the high-pressure tank by curing the resin-impregnated fibers in the primary intermediate production tank prepared in the first step by heat treatment by electromagnetic induction heating,
Heat treatment
Preparing a secondary intermediate production tank by applying a resin curing agent to the outer periphery of the primary intermediate production tank in a low-viscosity state lower than the temperature at which the resin-impregnated fibers start to cure; and A second step having a step of applying a curing reaction accelerator to the outer periphery of the secondary intermediate production tank after preparing and curing the resin-impregnated fiber to prepare a high-pressure tank,
Method for producing a high-pressure tank including

  According to the present invention, there is provided a method for manufacturing a high-pressure tank in which variation in Vf and reduction in tank strength are prevented.

The schematic diagram of an example of an IH heating hardening furnace is shown. FIG. 3 is a schematic view of an example of a mechanism for applying a curing agent and an accelerator in an IH heating curing furnace to the outer periphery of a tank according to a curing reaction state of a resin. FIG. 4 is a diagram illustrating an example of a heat treatment temperature profile (relation between time and work temperature) in a heat treatment step of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In this specification, features of the present invention will be described with reference to the drawings as appropriate. In the drawings, the size and shape of each part are exaggerated for clarity, and the actual size and shape are not accurately depicted. Therefore, the technical scope of the present invention is not limited to the size and shape of each part shown in these drawings. In addition, the manufacturing method of the high-pressure tank of the present invention is not limited to the following embodiment, and may be modified or improved by a person skilled in the art in various forms without departing from the gist of the present invention. Can be implemented.

  The present invention provides (1) a first step of preparing a primary intermediate production tank by winding resin-impregnated fibers around the outer periphery of a hollow liner serving as a tank container, and (2) a primary intermediate production tank prepared in the first step. The second step of preparing the high-pressure tank by curing the resin-impregnated fiber in the tank by heat treatment by electromagnetic induction heating, wherein the heat treatment is performed by (i) a primary intermediate in a low-viscosity state lower than the temperature at which the resin-impregnated fiber starts to cure. Preparing a secondary intermediate production tank by applying a curing agent for resin to the outer periphery of the production tank, and (ii) accelerating the curing reaction on the outer periphery of the secondary intermediate production tank after the temperature is equal to or higher than the temperature at which the resin-impregnated fibers start curing. A step of preparing a high-pressure tank by applying an agent and curing the resin-impregnated fibers, and a second step of manufacturing the high-pressure tank.

(1) First step of winding resin-impregnated fibers around the outer periphery of a hollow liner serving as a tank container In the first step of the present invention, the resin-impregnated fibers are wound around the outer periphery of a hollow liner serving as a tank container. Prepare the primary intermediate production tank.

  As a material of the liner, a container having a gas barrier property against hydrogen gas conventionally known in the technical field can be used. Examples of the material of the liner include, but are not limited to, metals such as aluminum, and hard resins such as polyethylene resin, polypropylene resin, and nylon resin. As a material of the liner, engineering plastics such as nylon resin are preferable because high strength and impact resistance are required.

  As the fibers in the resin-impregnated fibers, those conventionally known in the art can be used. Examples of the fiber include, but are not limited to, metal fiber, glass fiber, carbon fiber, inorganic fiber such as alumina fiber, synthetic organic fiber such as aramid fiber, and natural organic fiber such as cotton. These fibers may be used alone or in combination (as a mixed fiber). As the fiber, carbon fiber is preferable because of its light weight and high strength.

  As the resin in the resin-impregnated fiber, a resin that is thermally cured by a reaction with a resin curing agent conventionally known in the art can be used. Examples of the resin include, but are not limited to, phenol resin, urea resin, unsaturated polyester resin, vinyl ester resin, polyimide resin, bismaleimide resin, polyurethane resin, diallyl phthalate resin, and epoxy resin. As the resin, an epoxy resin is preferable since the adhesiveness of the fibers is required.

  As the epoxy resin, those conventionally known in the art can be used. Examples of the epoxy resin include, but are not limited to, bisphenol A type epoxy resin, bisphenol AD type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, glycidyl ester type epoxy resin and the like. . The epoxy resin may be linear or branched.

  Resin-impregnated fibers can be prepared by methods conventionally known in the art. The resin-impregnated fiber is not limited, but can be prepared, for example, by prepreg molding in which carbon fiber is impregnated with a liquid resin.

  The method of winding the resin-impregnated fiber around the outer periphery of the liner in the present invention can be performed by a conventionally known method. The method of winding the resin-impregnated fiber around the outer periphery of the liner in the present invention is not limited, and examples thereof include the following method.

  First, as a liner, for example, a resin container having gas barrier properties against hydrogen gas is prepared. The liner has a substantially cylindrical cylinder portion having a uniform radius, and a convex curved dome portion provided at both ends of the cylinder portion. The dome portion is constituted by a curved surface having an equal tension, and has a base at a vertex for connection to an external pipe or the like.

  Next, resin-impregnated fibers are wound around the outer periphery of the liner. For winding the resin-impregnated fiber, a conventionally known filament winding device can be used. The filament winding device can repeatedly wind resin-impregnated fibers around the outer periphery of the liner, and forms a fiber layer of resin-impregnated fibers around the outer periphery of the liner. When an epoxy resin is used as the resin and a carbon fiber is used as the fiber, a carbon fiber layer impregnated with the epoxy resin is formed as a fiber layer on the outer periphery of the liner. Thereby, a primary intermediate production tank having a fiber layer before resin curing on the outer periphery of the liner is obtained.

  The number of windings is not limited, but the resin-impregnated fibers are wound until the thickness of the fiber layer formed on the outer periphery of the liner is usually 10 mm to 30 mm.

(2) Second step of curing the resin-impregnated fiber in the primary intermediate production tank prepared in the first step by heat treatment by electromagnetic induction heating In the second step of the present invention, the primary intermediate produced in the first step is prepared. The resin-impregnated fibers in the tank are cured by heat treatment using electromagnetic induction heating to prepare a high-pressure tank.

  By the heat treatment by electromagnetic induction heating, the temperature of the primary intermediate production tank can be rapidly raised, and the resin-impregnated fibers can be uniformly and efficiently cured.

  In the second step, the heat treatment includes: (i) preparing a secondary intermediate production tank by applying a resin curing agent to the outer periphery of the primary intermediate production tank in a low-viscosity state lower than the temperature at which the resin-impregnated fibers start to cure. And (ii) preparing a high-pressure tank by applying a curing reaction accelerator to the outer periphery of the secondary intermediate production tank after setting the temperature at which the resin-impregnated fibers start to cure or higher, and curing the resin-impregnated fibers.

(I) A step of applying a resin curing agent to the outer periphery of the primary intermediate production tank in a low-viscosity state lower than the temperature at which the resin-impregnated fiber starts to cure. In the step (i), the low-temperature lower than the temperature at which the resin-impregnated fiber starts to cure. In the viscosity state, a curing agent for resin is applied to the outer periphery of the primary intermediate production tank to prepare a secondary intermediate production tank.

  The curing agent is not limited as long as a thermosetting resin conventionally known in the technical field can be obtained by a reaction. Examples of the curing agent include primary amines such as aliphatic amines, aromatic amines, and modified amines, secondary amines, and tertiary amines. Specifically, piperidine, N, N-dimethylpiperazine, Amine-based curing agents such as triethylenediamine, 2,4,6-tris (dimethylaminomethyl) phenol, benzyldimethylamine and 2- (dimethylaminomethyl) phenol; acid anhydride-based curing agents such as tetrahydrophthalic anhydride; mercaptan And a thiol-based curing agent such as triazine thiol. As the curing agent, an aromatic amine-based curing agent and an acid anhydride-based curing agent are preferable for shortening the curing time.

  In the step (i), a mechanism for applying the curing agent to the outer periphery of the tank is preferably present in the curing furnace so that the curing agent can be applied to the outer periphery of the primary intermediate production tank in the heat treatment. .

  In the step (i), the temperature lower than the temperature at which the resin-impregnated fiber starts to harden varies depending on the resin to be impregnated into the fiber. The range below the temperature at which the resin-impregnated fibers start to cure is preferably lower than the glass transition temperature, and more preferably the resin is in a low viscosity state. For example, when using an epoxy resin as the resin, since the curing temperature of the resin is 140 to 150 ° C, the temperature lower than the temperature at which the resin-impregnated fiber starts to cure is usually 80 ° C to 120 ° C, preferably 90 ° C to 100 ° C. .

  In the step (i), during the application of the curing agent, the temperature may be constant or may be increased as long as the temperature is lower than the temperature at which the resin-impregnated fibers start to cure.

  In the step (i), the resin in the resin-impregnated fiber has a low viscosity by applying a curing agent to the outer periphery of the primary intermediate production tank at a temperature lower than the temperature at which the resin-impregnated fiber starts to cure to prepare the secondary intermediate production tank. In this state, the crosslink density of the surface of the secondary intermediate production tank is increased, and while the air generated inside the fiber layer is taken out, the exudation of the resin on the inner layer side is suppressed.

(Ii) A step of applying a curing reaction accelerator to the outer periphery of the secondary intermediate production tank after setting the temperature at which the resin-impregnated fiber starts to be cured or higher, and curing the resin-impregnated fiber. After the temperature is set to be equal to or higher than the temperature at which curing starts, a curing reaction accelerator is applied to the outer periphery of the secondary intermediate production tank, and the resin-impregnated fibers are cured to prepare a high-pressure tank.

  The accelerator is not limited as long as it can promote a thermosetting reaction conventionally known in the art. Examples of the accelerator include capsule-type amines.

  In the step (ii), a mechanism for applying the accelerator to the outer periphery of the tank may be present in the curing furnace so that the accelerator can be applied to the outer periphery of the secondary intermediate production tank in the heat treatment. preferable.

  In the step (ii), the temperature at which the resin-impregnated fiber starts to harden varies depending on the resin to be impregnated into the fiber. The range above the temperature at which the resin-impregnated fiber starts to cure is preferably higher than the temperature, more preferably 20 ° C or higher.

  In the step (ii), the accelerator is preferably applied after the air generated inside the fiber layer of the secondary intermediate production tank is released.

  In the step (ii), during the application of the accelerator, the temperature may be constant or may increase as long as the temperature is equal to or higher than the temperature at which the resin-impregnated fiber starts to cure.

  In the step (ii), after the temperature is set to be equal to or higher than the temperature at which the resin-impregnated fiber starts to harden, an accelerator is applied to the outer periphery of the secondary intermediate production tank, and the resin-impregnated fiber is hardened to prepare a high-pressure tank. While suppressing the generation of air inside the fiber layer and near the fiber layer surface of the next intermediate production tank, the curing of the tank surface is promoted, and the resin on the inner layer side is prevented from seeping out.

  In the heat treatment, in order to efficiently perform the steps (i) and (ii), a mechanism for applying a curing agent and an accelerator to the outer periphery of the tank according to the curing reaction state of the resin is provided in the curing furnace. Preferably it is present.

  By the heat treatment according to the present invention, the resin density and the crosslink density on the outer layer side at the time of curing the resin are increased, and the exudation of the resin from the outermost layer can be prevented.

  FIG. 1 shows a schematic diagram of an example of the IH heating / curing furnace 1, and FIG. 2 shows a case where the curing agent and the accelerator in the IH heating / curing furnace 1 are applied to the outer periphery of the tank 3 according to the curing reaction state of the resin. FIG. 2 shows a schematic view of an example of the mechanism of FIG.

  In FIGS. 1 and 2, the IH heating / curing furnace 1 is configured as a high-frequency induction heating furnace, rotatably supports the tank 3 on a gantry via tank supporting shafts at both ends of the tank 3, and Thus, the tank 3 can be rotated during the heating process.

  Further, the IH heating curing furnace 1 has an induction heating coil 4. The induction heating coil 4 is provided so as to spirally surround the tank 3 that is pivotally supported along the tank longitudinal direction along the tank longitudinal direction. The induction heating coil 4 is connected to a high-frequency current generation power supply, receives control of the high-frequency current generation power supply by a control device, receives a high-frequency current, forms a magnetic flux, and induces a fiber layer using the resin-impregnated fiber of the tank 3 as a conductor. Heat.

  Also, at the upper part of the IH heating and curing furnace 1, a curing agent application nozzle 5 and a promoter that can move along the longitudinal direction of the tank so that the curing agent and the accelerator can be uniformly applied to the outer periphery of the tank. An application device 2 having an application nozzle 6 is provided. FIG. 2 illustrates a state in which the accelerator is applied to the tank 3 from the accelerator application nozzle 6.

  In the heat treatment using the IH heating / curing furnace 1, a tank shaft is mounted on the primary intermediate producing tank 3 before the primary intermediate producing tank 3 having the fiber layer formed thereon is carried into the IH heating / curing furnace 1. The tank supporting shaft is inserted into the bases at both ends of the intermediate production tank 3, and horizontally supports the primary intermediate production tank 3 via a gantry with the shafts protruding from both ends of the tank. After supporting the primary intermediate production tank 3 in this way, the IH heating and curing furnace 1 subjects the primary intermediate production tank 3 to heat treatment. In this heat treatment, the primary intermediate production tank 3 set on the gantry is rotated at a constant speed by the tank rotation mechanism 7 together with the tank support shaft, and the rotation is maintained during the heat treatment. Simultaneously with the rotation of the tank or at a constant speed, the IH heating / curing furnace 1 controls the induction heating coil 4 to supply a high-frequency current from a high-frequency current generating power supply to the induction heating coil 4 to induction-heat the fiber layer. In the IH heating and curing furnace 1, at a temperature lower than the temperature at which the resin-impregnated fiber starts to cure, the curing agent is uniformly applied to the outer periphery of the primary intermediate production tank 3 by the curing agent application nozzle 5 provided in the application device 2. During the application of the curing agent, the temperature may be constant or may increase as long as the temperature is lower than the temperature at which the resin-impregnated fibers start to cure. Further, the application of the curing agent to the primary intermediate production tank 3 may be performed immediately after the induction heating because it is sufficient that the temperature is lower than the temperature at which the resin-impregnated fibers start to cure. The application of the curing agent to the primary intermediate production tank 3 is completed to prepare the secondary intermediate production tank 3, and in the IH heating / curing furnace 1, when the temperature becomes equal to or higher than the temperature at which the resin-impregnated fibers start to cure, the secondary The above-mentioned accelerator is uniformly applied to the outer periphery of the intermediate production tank 3 by an accelerator application nozzle 6 provided in the application device 2. The application of the accelerator is preferably performed after the air generated inside the fiber layer of the secondary intermediate production tank is released. During the application of the accelerator, the temperature may be constant or may increase as long as the temperature is equal to or higher than the temperature at which the resin-impregnated fiber starts to cure. When the application of the accelerator to the secondary intermediate production tank is completed and the thermosetting of the thermosetting resin used for forming the fiber layer is completed, the heating is stopped and the cooling is started.

  For example, FIG. 3 shows an example of a heat treatment temperature profile using the mechanism in the heat treatment step of the present invention.

  In the heat treatment temperature profile of FIG. 3, in the IH heating / curing furnace 1, resin-impregnated fibers (fiber layers) of the primary intermediate production tank 3 rotated at a constant speed by the tank rotating mechanism 7, for example, carbon fibers impregnated with epoxy resin, are used. Then, a high-frequency current is supplied to the induction heating coil 4 from the high-frequency current generating power supply by the control device, and the induction heating is performed at a heating rate of about 2 ° C./min from room temperature of about 20 ° C. At about 100 ° C., which is lower than the temperature at which the resin-impregnated fiber starts to harden, in the IH heating and curing furnace 1, the above-mentioned curing agent, for example, an aromatic amine-based curing agent is provided on the outer periphery of the primary intermediate production tank 3 in the coating device 2. The hardener coating nozzle 5 is applied uniformly. During the application of the curing agent, the temperature is kept at about 100 ° C. At this temperature, the resin in the resin-impregnated fibers, for example, the epoxy resin, is in a low-viscosity state, and the application of the curing agent increases the crosslink density on the outer layer side of the fiber layer. After the application of the curing agent to the primary intermediate production tank 3 is completed and the secondary intermediate production tank 3 is prepared, in the IH heating / curing furnace 1, heating is resumed at a rate of about 3 ° C./min. When the temperature of the resin-impregnated fiber reaches about 120 ° C., which is equal to or higher than the temperature at which the resin-impregnated fiber starts to cure, the above-mentioned accelerator, for example, a capsule type amine, is coated on the outer periphery of the secondary intermediate production tank 3 with an accelerator coating nozzle provided in the coating device 2. 6. Apply evenly. During application of the accelerator, the temperature is increased at a rate of about 3 ° C / min. After the application of the accelerator to the secondary intermediate production tank 3 is completed, heating is performed at about 160 ° C., which is a temperature at which thermosetting of the thermosetting resin used for forming the fiber layer is sufficiently generated, and the heating is performed for about 40 minutes. Maintain 160 ° C. After curing is completed, heating is stopped and quenched to produce a high-pressure tank for a fuel cell.

1. 1. IH heating curing furnace; Coating device, 3. 3. Tanks (primary intermediate production tank, secondary intermediate production tank, high-pressure tank); 4. induction heating coil; 5. hardener application nozzle; 6. Accelerator application nozzle; Tank rotation mechanism

Claims (1)

A first step of winding a resin-impregnated fiber around the outer periphery of a hollow liner serving as a tank container to prepare a primary intermediate production tank,
The second step of preparing the high-pressure tank by curing the resin-impregnated fibers in the primary intermediate production tank prepared in the first step by heat treatment by electromagnetic induction heating,
Heat treatment
Preparing a secondary intermediate production tank by applying a resin curing agent to the outer periphery of the primary intermediate production tank in a low-viscosity state lower than the temperature at which the resin-impregnated fibers start to cure; and A second step having a step of applying a curing reaction accelerator to the outer periphery of the secondary intermediate production tank after preparing the resin-impregnated fiber to prepare a high-pressure tank,
A method for manufacturing a high-pressure tank including:

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