JP5644179B2 - Injection molding apparatus and injection molding method - Google Patents

Description

  The present invention relates to an injection molding apparatus and an injection molding method, and in particular, an injection molding apparatus for molding a molded body by heating and melting a resin or the like and injecting the resin into a resin flow part (cavity) of a molding die. The present invention relates to an injection molding method.

  Fuel cell vehicles and natural gas vehicles are equipped with a high-pressure tank for storing hydrogen gas, natural gas, or the like as fuel gas. As a high-pressure tank, a high-pressure tank is known in which a carbon fiber reinforced plastic material (CFRP material) having a very high strength per unit density is wound around the outer surface of a resin tank (liner: inner container) and reinforced. When manufacturing such a high-pressure tank, the fiber layer is wound around the outer surface of a resin tank (resin liner) in a state in which a fiber bundle such as carbon fiber is impregnated with a resin solution such as epoxy resin as in the filament winding method. There is a method of forming a reinforcing layer by curing the resin after forming the film.

  The resin liner is molded by, for example, injection molding in which a molding material resin is heated and melted and injected into a cavity of a molding die. For example, a resin is poured into a molding die, two molded bodies that are substantially semi-cylindrical bodies having a rib shape at the terminal portion are formed, and they are fitted to each other at the terminal portion having the rib shape. Are welded by a laser or the like to form a substantially cylindrical resin liner.

  If the resin flow length in the molding die is long and the resin flow terminal portion is a thin shape such as a rib shape, as in the molding of such a resin liner for high-pressure tanks, the resin during injection molding However, when flowing in the molding die, resin filling failure, burning, etc. may occur, or oxidatively deteriorated resin may remain at the end of the molded body. In addition, when laser welding is performed in such a state, defective welding such as burning or non-welding may occur during laser welding due to reasons such as laser not transmitting.

  In Patent Document 1, when an FRP reinforcing tank serving as a pressure vessel is molded, the time required for the molding process is shortened, and in order to allow resin impregnation to the inside of the molded product without generating voids, the core body is formed. A separable mold for sealing a wound body in which a reinforcing fiber layer is wound around a liner; a resin injector for injecting resin into the mold; a resin trap for receiving resin leaking from the mold; An apparatus for forming an FRP reinforced tank having a vacuum pump communicating with a resin trap, wherein a resin injection port is provided at one end of the mold, the resin injector is connected, and a vacuum is drawn at the other end. The resin trap is connected by providing a mouth, and a compressor is disposed in the resin injector so that a resin mixed with a predetermined curing agent is injected under pressure into the mold. Heating means for curing Molding apparatus of the FRP reinforcement tank provided in the mold is described.

  However, in the technique of Patent Document 1, it is not possible to suppress the resin filling failure in the resin flow terminal portion of the molded body, the occurrence of burning or the like, the residual of the oxidatively deteriorated resin, and the like, and the stable quality cannot be ensured.

JP 2007-125844 A

  The present invention is an injection molding apparatus and an injection molding method capable of ensuring stable quality of a molded body by injection molding.

The present invention is an injection molding apparatus for molding a heat-melted resin, a molding die having a resin flow part, and an inert gas supply means for supplying an inert gas to the resin flow part, A thermal processing member for thermally processing the resin in the resin flow terminal portion after injecting the heated and melted resin into the resin flow portion supplied with the inert gas into a predetermined shape in the molding die; Is an injection molding apparatus.

The present invention also relates to an injection molding method for molding a heat-melted resin, an inert gas supply step for supplying an inert gas to a resin flow part of a molding die, and the heat-melted resin as described above. An injection step of injecting into the resin flow part supplied with the inert gas, and using a heat heating member, the resin at the resin flow terminal part after injection into the resin flow part has a predetermined shape in the molding die. An injection molding method including a heat processing step for heat processing.

  In the present invention, by using the heat heating member, the resin in the resin flow terminal portion after being injected into the resin flow portion of the molding die is thermally processed into a predetermined shape in the molding die, thereby performing injection molding. An injection molding apparatus and an injection molding method capable of ensuring stable quality of a molded body are provided.

It is the schematic which shows the whole structure of an example of the injection molding apparatus which concerns on embodiment of this invention. (A)-(d) It is the schematic for demonstrating an example of the injection molding method which concerns on embodiment of this invention. It is the schematic which shows an example of the resin liner molded object for manufacturing a high-pressure tank. It is AA sectional drawing in FIG. It is the schematic which shows an example of the heat processing of the resin flow end part by the heat heating member in the injection molding method which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  An outline of an exemplary configuration of an injection molding apparatus according to an embodiment of the present invention is shown in FIG.

  As shown in FIG. 1, an injection molding apparatus 1 is an injection molding apparatus that molds a heat-melted resin, and a molding die 16 having a resin fluidizing portion 18 and an inert gas in the resin fluidizing portion 18. An inert gas supply flow path 24 serving as an inert gas supply means for supplying, and the resin at the resin flow terminal portion after injecting the heated and melted resin into the resin flow portion 18 are predetermined in the molding die 16. And a thermal blade 20 as a thermal processing member for thermal processing into the shape. The injection molding apparatus 1 may include a shielding member 22 as a movable shielding means for shielding the resin flow terminal portion when the heat-melted resin is injected into the resin flow portion 18. The injection molding apparatus 1 includes a heating cylinder 10 for heating and melting the resin, an injection screw 12 for injecting the heated and melted resin in the heating cylinder 10, and a heating cylinder 10. You may provide the resin supply apparatus 14 as a resin supply means for supplying the resin 26 for shaping | molding in the heating cylinder 10. FIG.

  In the injection molding apparatus 1, for example, a heating heater (not shown) or the like as a heating unit for heating the heating cylinder 10 is disposed around the cylinder portion of the heating cylinder 10. It comes to heat.

  The injection screw 12 has a shaft portion and a groove portion that is formed in a spiral shape around the shaft portion and for injecting the resin that is heated and melted in the heating cylinder 10. The shaft portion of the injection screw 12 is connected to a rotation driving means such as a motor (not shown).

  The resin supply device 14 is connected to the opening of the supply receiving portion of the heating cylinder 10 through a resin supply passage or the like. A valve or the like for opening and closing the resin supply passage may be installed in the middle of the resin supply passage.

  The heating cylinder 10 of the injection molding apparatus 1 is connected to the opening of the supply receiving portion of the molding die 16 via an injection nozzle or the like. The molding die 16 constitutes a resin flow part (cavity) 18 for molding a molded body such as a high-pressure tank resin liner.

  The molding die 16 is provided with an inert gas supply channel 24 leading to the resin flow part 18, and an inert gas is supplied to the resin flow part 18 from an inert gas supply device (not shown) through the inert gas supply channel 24. It is configured to be.

  In the molding die 16, when the heat-melted resin is injected into the resin flow portion 18, the resin flow terminal portion is shielded by the movable shielding member 22, and the resin is injected into the resin flow portion 18. When the resin in the resin flow terminal portion after the heat treatment is thermally processed into a predetermined shape by the hot blade 20, the shielding member 22 is moved to open the resin flow terminal portion.

  The operation of the injection molding method and the injection molding apparatus 1 according to the present embodiment will be described with reference to FIGS.

  First, the molding die 16 is closed, and the resin flow terminal portion of the resin flow portion 18 is shielded by the shielding member 22. When the mold clamping of the molding die 16 is completed, the inert gas is supplied into the resin flow portion 18 of the molding die 16 through the inert gas supply flow path 24 in performing the injection molding ( FIG. 2A, inert gas supply step). As a result, it is possible to prevent oxidation during the melting operation of the resin by heating or the like inside the molding die 16. Prior to the inert gas supply step, the resin flow part 18 of the molding die 16 may be deaerated under reduced pressure by a depressurization means such as a vacuum pump (not shown) to form a vacuum state (depressurization deaeration step).

  Resin is supplied from a resin supply source to the resin supply device 14 in FIG. 1, and a predetermined amount of the resin supplied to the resin supply device 14 is supplied from the opening into the heating cylinder 10 by an opening / closing operation of a valve or the like. The heating cylinder 10 is heated by a heater or the like, and the temperature in the heating cylinder 10 is controlled to be within a predetermined heating temperature range by a temperature sensor, a control unit, or the like. The resin in the heating cylinder 10 is heated and melted by the heating of the heating cylinder 10.

  The injection screw 12 is controlled by a rotation operation by a rotation driving means or the like and a linear movement operation in the axial direction, and the molten resin is injected from the heating cylinder 10 into the resin flow portion 18 of the molding die 16 (see FIG. 2 (b), injection process). After the injection is completed, the molten resin is cooled or allowed to cool in the molding die 16 as necessary to be in a semi-cured state (semi-curing step). Thereafter, the shielding member 22 is moved to open the resin flow terminal portion, and the heated blade 20 having a predetermined shape and heated is pressed to thermally process the resin of the resin flow terminal portion into a predetermined shape ( FIG. 2C, thermal processing step). When the cooling of the molded body is completed after the thermal processing step (cooling step), after the mold is opened, the molded body 30 is extruded from the molding die 16 and taken out to be a finished product (FIG. 2 (d), taken out) Process). In the case of continuous molding, the above cycle may be repeated.

  In the present specification, the “semi-cured state” refers to a state before the resin is completely cured.

  Examples of the inert gas include nitrogen gas, argon gas, helium gas, and the like.

  The thermal processing member such as the thermal blade 20 is heated by a heating means (not shown), and the surface temperature of the thermal blade 20 is not particularly limited as long as it is higher than the curing temperature of the resin used for molding. The curing temperature of the resin used may be in the range of + 50 ° C. to + 180 ° C.

  The thermally processed member is, for example, a hot blade made of metal such as iron or stainless steel. The shape of the heat-processed member is set based on the shape required for the resin flow terminal according to the use of the molded body to be molded, the post-processing step of the molded body, and the like. If necessary, the resin flow terminal portion may be formed to be thicker than other portions and heat-processed with a heat-processed member. For example, when the molded body is a resin liner for a high-pressure tank as shown in FIGS. 3 and 4, the resin flow terminal portion of the molded body 30 is molded into a thick wall as shown in FIG. 5 and a hot blade 20 having a wedge shape is formed. Thus, the shape of the welding rib 32 may be obtained.

  In this embodiment, the use of a temperature-controlled heated inert gas has an effect of improving the activity. What is necessary is just to set it as 100 degreeC-150 degreeC as temperature of a heating inert gas, for example.

  As described above, the inside of the molding die 16 is once evacuated as necessary before injection of the resin, and then filled with an inert gas, and then injected and filled with the resin, and then the resin flow end portion. The shape of the resin can be processed with the hot blade 20 at a high temperature in the molding die 16 so that a favorable shape of the resin flow end portion can be processed. In particular, as in molding of a resin liner for a high-pressure tank for fuel cells or the like, molding in which the resin flow length in the molding die 16 is long and the resin flow terminal portion is a thin shape such as a rib shape It is especially effective for the body. Even in such a molded body, when the resin flows in the molding die 16 at the time of injection molding, resin filling failure, burning or the like occurs, or oxidation-degraded resin is present at the terminal portion of the molded body. It can suppress remaining, and can ensure stable quality.

  When the weld rib shape is post-processed in a post-process after molding the molded body, the resin is almost completely solidified, and processing is usually difficult and requires a long time. Further, when heat processing is performed at a high temperature, thermal deterioration (oxidation deterioration) may occur. By heat-processing the resin flow end portion in the molding die 16 with a high-temperature hot blade 20 as in the present embodiment, it is possible to prevent poor resin filling, burning, and oxidative degradation of the resin in the resin flow end portion. At the same time, by filling the inside of the molding die 16 with a heated inert gas, it is possible to prevent oxidative degradation of the resin due to the thermal processing with the high-temperature hot blade 20. Moreover, since it can heat-process in the middle of shaping | molding in the metal mold | die 16 for shaping | molding, the malfunction of a resin flow terminal part can be prevented and stable quality can be ensured, without reducing productivity.

  The injection molding apparatus and the injection molding method according to the present embodiment can be used for manufacturing various molded products such as a resin liner, a bumper, and an intake manifold for a high-pressure tank. In particular, it can be suitably used for the production of a resin liner for a high-pressure tank that requires high quality such as pressure resistance.

  The high-pressure tank is a tank that stores hydrogen gas, natural gas, or the like as fuel gas, which is mounted on a fuel cell vehicle or a natural gas vehicle. As a high-pressure tank, a high-pressure tank reinforced with a reinforcing layer (outer layer) in which a carbon fiber reinforced plastic material (CFRP material) with extremely high strength per unit density is wrapped around the outer surface of a resin tank (liner: inner container) is known. It has been. When manufacturing such a high-pressure tank, a fiber layer is formed by wrapping around a resin liner with a matrix resin such as an uncured epoxy resin impregnated in a fiber bundle such as carbon fiber as in the filament winding method. Then, there is a method of forming a reinforcing layer by curing the matrix resin.

  A liner composed of a resin material is formed by, for example, injection molding of the resin. For example, by pouring a resin such as a polyamide resin into a molding die, two molded bodies 30 that are substantially semi-cylindrical bodies having rib-shaped welding ribs 32 at the terminal portions as shown in FIGS. The end portions having a rib shape are fitted with each other, and the fitting portions are welded by a laser or the like, thereby forming a substantially cylindrical resin liner. By this injection molding, a resin liner having a substantially uniform thickness is formed.

  When the molded body 30 for a resin liner for a high-pressure tank as shown in FIG. 3 is injection-molded as the molded body, the resin flow terminal portion has the shape of a welding rib 32 as shown in FIGS. The deteriorated resin is likely to remain on the welding rib 32, and if laser welding is performed in this state, the laser is not easily transmitted, and welding defects such as burning and non-welding may occur during laser welding. With the molding method and molding apparatus according to the present embodiment, the resin that has been oxidized and deteriorated during molding enters the molding die and enters the molding body with respect to the molded body that is laser-welded, such as a resin liner for high-pressure tanks. Therefore, it is possible to prevent the occurrence of defective welding and the like, and to ensure stable molding and welding quality.

  The resin liner is formed in a substantially cylindrical shape or the like, for example, for accommodating a medium such as high-pressure hydrogen gas therein, and is a layer in direct contact with a gas such as hydrogen gas. The shape, size, and thickness of the resin liner can be arbitrarily selected according to the purpose of use and specifications. The thickness of the resin liner is, for example, in the range of 2 mm to 4 mm.

  Examples of the resin material constituting the liner include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinyl chloride, ABS resin, polystyrene, polyamide, polycarbonate, polyimide, and fluorine resin. Examples of the thermosetting resin include epoxy resin and polyurethane. The thickness of the liner and the type of material constituting the liner can be appropriately selected according to the strength, hermeticity, moldability, etc. required for the liner. Of these, polyamide resins such as nylon are preferable from the viewpoint of strength and gas permeability resistance.

  The reinforcing layer is a layer that is provided so as to cover the outer side of the liner and reinforces the liner, and includes, for example, a fiber and a matrix resin. Examples of the fibers constituting the reinforcing layer include glass fibers, carbon fibers, aramid fibers, and metal fibers.

  Moreover, as a matrix resin which comprises a reinforcement layer, a thermoplastic resin, a thermosetting resin, etc. are mentioned. Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinyl chloride, ABS resin, polystyrene, polyamide, polycarbonate, polyimide, and fluorine resin. Examples of the thermosetting resin include epoxy resin and polyurethane. Among these, an epoxy resin is preferable from the viewpoint of strength and adhesiveness.

  The reinforcing layer can be formed by, for example, winding the fiber bundle of fibers around the outer surface of the liner in a state where the matrix resin solution is impregnated, and then curing the resin. The thickness of the reinforcing layer can be adjusted by the number of layers of the fiber bundle to be wound.

  The high-pressure tank using the molded body obtained by the molding method and molding apparatus according to the present embodiment is, for example, a high-pressure tank that is mounted on a moving body and stores high-pressure gas therein. The high-pressure tank may be a stationary high-pressure tank.

  Here, examples of the moving body include two-wheeled vehicles, automobiles having four or more wheels such as buses and passenger cars, trains, ships, airplanes, robots, and the like, and particularly fuel cell vehicles. Examples of the high pressure gas include hydrogen gas and compressed natural gas.

  DESCRIPTION OF SYMBOLS 1 Injection molding apparatus, 10 Heating cylinder, 12 Injection screw, 14 Resin supply apparatus, 16 Mold for molding, 18 Resin flow part, 20 Hot blade, 22 Shield member, 24 Inert gas supply flow path, 26 Resin, 30 Molding Body, 32 welding ribs.

Claims (2)

An injection molding device for molding a heat-melted resin,
A molding die having a resin flow part;
An inert gas supply means for supplying an inert gas to the resin flow part;
A thermal processing member for thermally processing the resin in the resin flow terminal portion after injecting the heated and melted resin into the resin flow portion supplied with the inert gas into a predetermined shape in the molding die;
An injection molding apparatus comprising: An injection molding method for molding a heat-melted resin,
An inert gas supply step of supplying an inert gas to the resin flow part of the molding die;
An injection step of injecting the heated and melted resin into the resin flow part supplied with the inert gas ;
A thermal processing step of heat-processing the resin of the resin flow terminal portion after being injected into the resin flow portion into a predetermined shape in the molding die using a heat heating member,
An injection molding method comprising:

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